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1

Peak oil: The four stages of a new idea  

Science Journals Connector (OSTI)

The present paper reviews the reactions and the path of acceptance of the theory known as “peak oil”. The theory was proposed for the first time by M.K. Hubbert in the 1950s as a way to describe the production pattern of crude oil. According to Hubbert, the production curve is “bell shaped” and approximately symmetric. Hubbert's theory was verified with good approximation for the case of oil production in the United States that peaked in 1971, and is now being applied to the worldwide oil production. It is generally believed that the global peak of oil production (“peak oil”) will take place during the first decade of the 21st century, and some analysts believe that it has already occurred in 2005 or 2006. The theory and its consequences have unpleasant social and economical implications. The present paper is not aimed at assessing the peak date but offers a discussion on the factors that affect the acceptance and the diffusion of the concept of “peak oil” with experts and with the general public. The discussion is based on a subdivision of “four stages of acceptance”, loosely patterned after a sentence by Thomas Huxley.

Ugo Bardi

2009-01-01T23:59:59.000Z

2

E-Print Network 3.0 - addressing cancer clusters Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

addressing cancer clusters Search Powered by Explorit Topic List Advanced Search Sample search results for: addressing cancer clusters Page: << < 1 2 3 4 5 > >> 1 THE PUBLIC HEALTH...

3

Reverse osmosis concentrate treatment by a PAC countercurrent four-stage adsorption/MF hybrid process  

Science Journals Connector (OSTI)

Abstract In this study, in order to reduce the impact of reverse osmosis concentrate (ROC) on the receiving body of water and/or improve the recovery rate of reverse osmosis (RO) system by reusing the treated ROC as a feeding, a powdered activated carbon (PAC) countercurrent four-stage adsorption/MF hybrid process was developed for organic removal from ROC. The process could achieve good organic removal at lower PAC consumption. For dissolved organic carbon (DOC) removal efficiency of 70.0%, the PAC dose was 21.6% less than that in countercurrent two-stage adsorption and 50.9% less than that in single-stage adsorption. The calculation method for correlating removal efficiency and PAC dose was deduced and validated. The validation result showed that the relative error between the average experimental DOC removal efficiency and the calculated one was less than 5% throughout the experiment, exhibiting good accuracy for the calculation method. Compared with countercurrent two-stage adsorption, the membrane fouling in the new process could be mitigated to a certain extent. The total number of sub-cycles in a cycle (n) influenced the hydraulic retention time (HRT) and the total volume of the reactors. Results showed that the HRT increased as n increased.

Xiaozhu Wei; Ping Gu; Guanghui Zhang

2014-01-01T23:59:59.000Z

4

Chemical Enrichment RGS cluster sample (CHEERS): Constraints on turbulence  

E-Print Network [OSTI]

Feedback from AGN, galactic mergers, and sloshing are thought to give rise to turbulence, which may prevent cooling in clusters. We aim to measure the turbulence in clusters of galaxies and compare the measurements to some of their structural and evolutionary properties. It is possible to measure the turbulence of the hot gas in clusters by estimating the velocity widths of their X-ray emission lines. The RGS Spectrometers aboard XMM-Newton are currently the only instruments provided with sufficient effective area and spectral resolution in this energy domain. We benefited from excellent 1.6Ms new data provided by the CHEERS project. The new observations improve the quality of the archival data and allow us to place constraints for some clusters, which were not accessible in previous work. One-half of the sample shows upper limits on turbulence less than 500km/s. For several sources, our data are consistent with relatively strong turbulence with upper limits on the velocity widths that are larger than 1000km/...

Pinto, Ciro; Werner, Norbert; de Plaa, Jelle; Fabian, Andrew C; Zhang, Yu-Ying; Kaastra, Jelle S; Finoguenov, Alexis; Ahoranta, Jussi

2015-01-01T23:59:59.000Z

5

Sampling Within k-Means Algorithm to Cluster Large Datasets  

SciTech Connect (OSTI)

Due to current data collection technology, our ability to gather data has surpassed our ability to analyze it. In particular, k-means, one of the simplest and fastest clustering algorithms, is ill-equipped to handle extremely large datasets on even the most powerful machines. Our new algorithm uses a sample from a dataset to decrease runtime by reducing the amount of data analyzed. We perform a simulation study to compare our sampling based k-means to the standard k-means algorithm by analyzing both the speed and accuracy of the two methods. Results show that our algorithm is significantly more efficient than the existing algorithm with comparable accuracy. Further work on this project might include a more comprehensive study both on more varied test datasets as well as on real weather datasets. This is especially important considering that this preliminary study was performed on rather tame datasets. Also, these datasets should analyze the performance of the algorithm on varied values of k. Lastly, this paper showed that the algorithm was accurate for relatively low sample sizes. We would like to analyze this further to see how accurate the algorithm is for even lower sample sizes. We could find the lowest sample sizes, by manipulating width and confidence level, for which the algorithm would be acceptably accurate. In order for our algorithm to be a success, it needs to meet two benchmarks: match the accuracy of the standard k-means algorithm and significantly reduce runtime. Both goals are accomplished for all six datasets analyzed. However, on datasets of three and four dimension, as the data becomes more difficult to cluster, both algorithms fail to obtain the correct classifications on some trials. Nevertheless, our algorithm consistently matches the performance of the standard algorithm while becoming remarkably more efficient with time. Therefore, we conclude that analysts can use our algorithm, expecting accurate results in considerably less time.

Bejarano, Jeremy [Brigham Young University; Bose, Koushiki [Brown University; Brannan, Tyler [North Carolina State University; Thomas, Anita [Illinois Institute of Technology; Adragni, Kofi [University of Maryland; Neerchal, Nagaraj [University of Maryland; Ostrouchov, George [ORNL

2011-08-01T23:59:59.000Z

6

A statistically-selected Chandra sample of 20 galaxy clusters -- I. Temperature and cooling time profiles  

E-Print Network [OSTI]

We present an analysis of 20 galaxy clusters observed with the Chandra X-ray satellite, focussing on the temperature structure of the intracluster medium and the cooling time of the gas. Our sample is drawn from a flux-limited catalogue but excludes the Fornax, Coma and Centaurus clusters, owing to their large angular size compared to the Chandra field-of-view. We describe a quantitative measure of the impact of central cooling, and find that the sample comprises 9 clusters possessing cool cores and 11 without. The properties of these two types differ markedly, but there is a high degree of uniformity amongst the cool core clusters, which obey a nearly universal radial scaling in temperature of the form T \\propto r^~0.4, within the core. This uniformity persists in the gas cooling time, which varies more strongly with radius in cool core clusters (t_cool \\propto r^~1.3), reaching t_cool <1Gyr in all cases, although surprisingly low central cooling times (<5Gyr) are found in many of the non-cool core systems. The scatter between the cooling time profiles of all the clusters is found to be remarkably small, implying a universal form for the cooling time of gas at a given physical radius in virialized systems, in agreement with recent previous work. Our results favour cluster merging as the primary factor in preventing the formation of cool cores.

Alastair J. R. Sanderson; Trevor J. Ponman; Ewan O'Sullivan

2006-08-21T23:59:59.000Z

7

The Bologna Open Cluster Chemical Evolution (BOCCE) Project: midterm results from the photometric sample  

E-Print Network [OSTI]

We describe a long term project aimed at deriving information on the chemical evolution of the Galactic disk from a large sample of open clusters. The main property of this project is that all clusters are analyzed in a homogeneous way, to guarantee the robustness of the ranking in age, distance and metallicity. Special emphasis is devoted to the evolution of the earliest phases of the Galactic disk evolution, where clusters have superior reliability with respect to other types of evolution indicators. The project is twofold: on the one hand we derive age, distance and reddening (and indicative metallicity) interpreting deep and accurate photometric data with stellar evolution models, and, on the other hand, we derive the chemical abundances from high-resolution spectroscopy. Here we describe our overall goals and approaches, and report on the mid-term project status of the photometric part, with 16 clusters already studied, covering an age interval from 0.1 to 6 Gyr and Galactocentric distances from 6.6 to 21 kpc. The importance of quantifying the theoretical uncertainties by deriving the cluster parameters with various sets of stellar models is emphasized. Stellar evolution models assuming overshooting from convective regions appear to better reproduce the photometric properties of the cluster stars. The examined clusters show a clear metallicity dependence on the Galactocentric distance and no dependence on age. The tight relation between cluster age and magnitude difference between the main sequence turn off and the red clump is confirmed.

Angela Bragaglia; Monica Tosi

2005-11-01T23:59:59.000Z

8

Chronology-Sensitive Hierarchical Clustering of Pyrosequenced DNA Samples of E. coli: A Case Study  

E-Print Network [OSTI]

; pyro- gram; I. INTRODUCTION Escherichia coli (E. coli) are commensal inhabitants of the human gut[1 to investigate the variation in E. coli. Characterizing E. coli populations and their variation in humansChronology-Sensitive Hierarchical Clustering of Pyrosequenced DNA Samples of E. coli: A Case Study

Dekhtyar, Alexander

9

Using Dynamic Quantum Clustering to Analyze Hierarchically Heterogeneous Samples on the Nanoscale  

SciTech Connect (OSTI)

Dynamic Quantum Clustering (DQC) is an unsupervised, high visual data mining technique. DQC was tested as an analysis method for X-ray Absorption Near Edge Structure (XANES) data from the Transmission X-ray Microscopy (TXM) group. The TXM group images hierarchically heterogeneous materials with nanoscale resolution and large field of view. XANES data consists of energy spectra for each pixel of an image. It was determined that DQC successfully identifies structure in data of this type without prior knowledge of the components in the sample. Clusters and sub-clusters clearly reflected features of the spectra that identified chemical component, chemical environment, and density in the image. DQC can also be used in conjunction with the established data analysis technique, which does require knowledge of components present.

Hume, Allison; /Princeton U. /SLAC

2012-09-07T23:59:59.000Z

10

INFRARED AND ULTRAVIOLET STAR FORMATION IN BRIGHTEST CLUSTER GALAXIES IN THE ACCEPT SAMPLE  

SciTech Connect (OSTI)

We present infrared (IR) and ultraviolet (UV) photometry for a sample of brightest cluster galaxies (BCGs). The BCGs are from a heterogeneous but uniformly characterized sample, the Archive of Chandra Cluster Entropy Profile Tables (ACCEPT), of X-ray galaxy clusters from the Chandra X-ray telescope archive with published gas temperature, density, and entropy profiles. We use archival Galaxy Evolution Explorer (GALEX), Spitzer Space Telescope, and Two Micron All Sky Survey (2MASS) observations to assemble spectral energy distributions (SEDs) and colors for BCGs. We find that while the SEDs of some BCGs follow the expectation of red, dust-free old stellar populations, many exhibit signatures of recent star formation in the form of excess UV or mid-IR emission, or both. We establish a mean near-UV (NUV) to 2MASS K color of 6.59 {+-} 0.34 for quiescent BCGs. We use this mean color to quantify the UV excess associated with star formation in the active BCGs. We use both fits to a template of an evolved stellar population and library of starburst models and mid-IR star formation relations to estimate the obscured star formation rates (SFRs). We show that many of the BCGs in X-ray clusters with low central gas entropy exhibit enhanced UV (38%) and mid-IR emission (43%) from 8 to 160 {mu}m, above that expected from an old stellar population. These excesses are consistent with ongoing star formation activity in the BCG, star formation that appears to be enabled by the presence of high-density, X-ray-emitting intergalactic gas in the core of the cluster of galaxies. This hot, X-ray-emitting gas may provide the enhanced ambient pressure and some of the fuel to trigger star formation. This result is consistent with previous works that showed that BCGs in clusters with low central gas entropies host H{alpha} emission-line nebulae and radio sources, while clusters with high central gas entropy exhibit none of these features. GALEX UV and Spitzer mid-IR measurements combined provide a complete picture of unobscured and obscured star formation occurring in these systems. We present IR and UV photometry and estimated equivalent continuous SFRs for a sample of BCGs.

Hoffer, Aaron S.; Donahue, Megan; Hicks, Amalia [Physics and Astronomy Department, Michigan State University, East Lansing, MI 48824-2320 (United States); Barthelemy, R. S., E-mail: hofferaa@msu.edu, E-mail: donahue@pa.msu.edu, E-mail: hicksam@msu.edu, E-mail: ramon.s.barthelemy@wmich.edu [Physics Department, Western Michigan University, Kalamazoo, MI 49008-5252 (United States)

2012-03-01T23:59:59.000Z

11

E-Print Network 3.0 - association studies clustering Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

of Three Document Clustering Algorithms: TreeCluster, Summary: with the TreeCluster algorithm. Usability studies will also shed light on what methods cater to user preferences......

12

E-Print Network 3.0 - approximate coupled cluster Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

ducted to show the efficiency of the proposed... . If a cluster Vk con- tains Nk coupled processes with mutual connectivity , then the cluster strength... of the clustering...

13

E-Print Network 3.0 - atomic clusters Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Brenner potential, the clustering process starting from 500 isolated carbon atoms in gas phase... clustering process with addition of 1 % of metal atoms was compared with the...

14

E-Print Network 3.0 - atomic clusters rb12 Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Brenner potential, the clustering process starting from 500 isolated carbon atoms in gas phase... clustering process with addition of 1 % of metal atoms was compared with the...

15

Galaxy Clustering Evolution in the CNOC2 High-Luminosity Sample  

E-Print Network [OSTI]

The redshift evolution of the galaxy two-point correlation function is a fundamental cosmological statistic. To identify similar galaxy populations at different redshifts, we select a strict volume-limited sample culled from the 6100 cataloged CNOC2 galaxies. Our high-luminosity subsample selects galaxies having k-corrected and evolution-compensated R luminosities, M_R^{k,e}, above -20 mag (H_0=100 km/s/Mpc) where M_ast^{k,e}(R)simeq -20.3 mag. This subsample contains about 2300 galaxies distributed between redshifts 0.1 and 0.65 spread over a total of 1.55 square degrees of sky. A similarly defined low-redshift sample is drawn from the Las Campanas Redshift Survey. We find that the co-moving two-point correlation function can be described as xi(r|z) = (r_00/r)^gamma (1+z)^{-(3+epsilon-gamma)} with r_{00}=5.03+/-0.08/h Mpc, epsilon=-0.17+/- 0.18 and gamma=1.87+/-0.07 over the z=0.03 to 0.65 redshift range, for Omega_M=0.2, Lambda=0. The measured clustering amplitude and its evolution are dependent on the adopted cosmology. The measured evolution rates for Omega_M=1 and flat Omega_M=0.2 background cosmologies are epsilon=0.80+/-0.22 and epsilon=-0.81+/-0.19, respectively, with r_{00} of 5.30+/-0.1/h Mpc and 4.85+/-0.1/h Mpc, respectively. The sensitivity of the derived correlations to the evolution corrections and details of the measurements is presented. The analytic prediction of biased clustering evolution for only the low density, LambdaCDM cosmology is readily consistent with the observations, with biased clustering in an open cosmology somewhat marginally excluded and a biased Omega_M=1 model predicting clustering evolution that is more than 6 standard deviations from the measured value.

R. G. Carlberg; H. K. C. Yee; S. L. Morris; H. Lin; P. B. Hall; D. Patton; M. Sawicki; C. W. Shepherd

1999-10-14T23:59:59.000Z

16

Cosmological Implications and Physical Properties of an X-Ray Flux-Limited Sample of Galaxy Clusters  

E-Print Network [OSTI]

The original abstract significantly exceeds the space available here, so here's a brief summary. The abstract is similar to the abstract of astro-ph/0111285 (ApJ, 567, 716) which describes the X-ray galaxy cluster sample HIFLUGCS, the X-ray luminosity--gravitational mass relation, the cluster mass function, and the derived cosmological constraints. Additionally, the fraction of the total gravitating mass in the universe which is contained in intracluster gas is quantified. Furthermore, physical properties of the cluster sample have been studied and analyses of relations between different cluster parameters (including the gas mass fraction, gas temperature, X-ray luminosity, gas mass, gravitational mass, beta, and core radius) are discussed. Also, results from an analysis of XMM-Newton performance verification phase data of Abell 1835 are described.

Thomas H. Reiprich

2003-08-08T23:59:59.000Z

17

E-Print Network 3.0 - american history cluster Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

about people's age, gender, education, job history... , spending patterns, debts, medical history, etc. Clustering could be applied to the database to find groups... Meta...

18

E-Print Network 3.0 - applying cluster enrichment Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Information Sciences 4 Discovery and Annotation of Functional Chromatin Signatures in the Human Genome Summary: direction. We therefore apply an unbiased clustering and alignment...

19

E-Print Network 3.0 - alter salt-induced clusterization Sample...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

A Late Fusion Approach Using Latent Models Eric Bruno Viper group, Computer... .Marchand-Maillet@unige.ch ABSTRACT Multi-view clustering is an important problem in informa-...

20

E-Print Network 3.0 - aluminium cluster al4h6 Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

An advanced diffusion model to identify emergent research issues: the case of optoelectronic devices Summary: is a diachronic cluster analysis. With the diffusion model we...

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

E-Print Network 3.0 - ar cluster impact Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

clustering four complex proces- sor structures, (1... observed by instructions in the pipeline. The additional latencies ... Source: Wang, Deli - Department of Electrical and...

22

E-Print Network 3.0 - alkali clusters formed Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

In recent years there have been a number of studies of gas-phase alkali halide cluster ions... reports which found only ions of the ... Source: Lineberger, W. Carl - JILA &...

23

A Systematic Search for High Surface Brightness Giant Arcs in a Sloan Digital Sky Survey Cluster Sample  

E-Print Network [OSTI]

We present the results of a search for gravitationally-lensed giant arcs conducted on a sample of 825 SDSS galaxy clusters. Both a visual inspection of the images and an automated search were performed and no arcs were found. This result is used to set an upper limit on the arc probability per cluster. We present selection functions for our survey, in the form of arc detection efficiency curves plotted as functions of arc parameters, both for the visual inspection and the automated search. The selection function is such that we are sensitive only to long, high surface brightness arcs with g-band surface brightness mu_g 10. Our upper limits on the arc probability are compatible with previous arc searches. Lastly, we report on a serendipitous discovery of a giant arc in the SDSS data, known inside the SDSS Collaboration as Hall's arc.

J. Estrada; J. Annis; H. T. Diehl; P. B. Hall; T. Las; H. Lin; M. Makler; K. W. Merritt; V. Scarpine; S. Allam; D. Tucker

2007-01-12T23:59:59.000Z

24

SUNYAEV-ZEL'DOVICH-MEASURED PRESSURE PROFILES FROM THE BOLOCAM X-RAY/SZ GALAXY CLUSTER SAMPLE  

SciTech Connect (OSTI)

We describe Sunyaev-Zel'dovich (SZ) effect measurements and analysis of the intracluster medium (ICM) pressure profiles of a set of 45 massive galaxy clusters imaged using Bolocam at the Caltech Submillimeter Observatory. We deproject the average pressure profile of our sample into 13 logarithmically spaced radial bins between 0.07R{sub 500} and 3.5R{sub 500}, and we find that a generalized Navarro, Frenk, and White (gNFW) profile describes our data with sufficient goodness-of-fit and best-fit parameters (C{sub 500}, {alpha}, {beta}, {gamma}, P{sub 0} = 1.18, 0.86, 3.67, 0.67, 4.29). We use X-ray data to define cool-core and disturbed subsamples of clusters, and we constrain the average pressure profiles of each of these subsamples. We find that, given the precision of our data, the average pressure profiles of disturbed and cool-core clusters are consistent with one another at R {approx}> 0.15R{sub 500}, with cool-core systems showing indications of higher pressure at R {approx}< 0.15R{sub 500}. In addition, for the first time, we place simultaneous constraints on the mass scaling of cluster pressure profiles, their ensemble mean profile, and their radius-dependent intrinsic scatter between 0.1R{sub 500} and 2.0R{sub 500}. The scatter among profiles is minimized at radii between {approx_equal} 0.2R{sub 500} and {approx_equal} 0.5R{sub 500}, with a value of {approx_equal} 20%. These results for the intrinsic scatter are largely consistent with previous analyses, most of which have relied heavily on X-ray derived pressures of clusters at significantly lower masses and redshifts compared to our sample. Therefore, our data provide further evidence that cluster pressure profiles are largely universal with scatter of {approx_equal} 20%-40% about the universal profile over a wide range of masses and redshifts.

Sayers, J.; Czakon, N. G.; Golwala, S. R.; Downes, T. P.; Mroczkowski, T.; Siegel, S. [Division of Physics, Math, and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Mantz, A. [Kavli Institute for Cosmological Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Ameglio, S.; Pierpaoli, E.; Shitanishi, J. A. [University of Southern California, Los Angeles, CA 90089 (United States); Koch, P. M.; Lin, K.-Y.; Umetsu, K. [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China); Maughan, B. J.; Van der Pyl, N. [H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol Bs8 ITL (United Kingdom); Molnar, S. M. [LeCosPA Center, National Taiwan University, Taipei 10617, Taiwan (China); Moustakas, L., E-mail: jack@caltech.edu [Jet Propulsion Laboratory, Pasadena, CA 91109 (United States)

2013-05-10T23:59:59.000Z

25

Evolution of the Intracluster Medium Between 0.2 < z < 1.3 in a Chandra Sample of 70 Galaxy Clusters  

E-Print Network [OSTI]

We study the evolution of the ICM with a sample of 70 galaxy clusters spanning 0.18 < z < 1.24. We find that X-ray luminosity and ICM mass at a fixed temperature evolve with redshift in a manner inconsistent with the standard self-similar model of cluster formation. Both luminosity and ICM mass evolve more slowly toward high redshift than the self-similar prediction. We find that evolution in these two observables can be modeled by a simple evolution in the cluster gas mass fraction. Excluding cluster cores from measurements results in evolution more consistent with the self-similar model than when the entire cluster is used, indicating that the fraction of clusters with cool cores increases with time, or that cool cores become more developed over time in those clusters that have them; this is supported by direct study of the redshift dependence of central surface brightness, which increases in scatter and magnitude at low redshift. We find that isophotal size-temperature relations evolve differently according to which isophote is used, indicating that the central and outer regions of cluster ICM evolve differently. We show that constraints on the evolution of the gas fraction and isophotal size-temperature relations constraints can be combined to measure cluster distances, and thus to constrain cosmological parameters. There are indications that scaling relation scatter decreases at higher redshift, suggesting that merging is not the dominant source of cluster structural variation. Our results provide constraints for simulations attempting to model cluster physics, indicate some difficulties for cosmological studies that assume constant cluster gas fractions, and point toward other potentially more robust uses of clusters for cosmological applications. (Abridged)

T. B. O'Hara; J. J. Mohr; A. J. R. Sanderson

2007-10-31T23:59:59.000Z

26

Small-sample brain mapping: sparse recovery on spatially correlated designs with randomization and clustering  

E-Print Network [OSTI]

Small-sample brain mapping: sparse recovery on spatially correlated designs with randomization Abstract Functional neuroimaging can measure the brain's response to an external stimulus. It is used to perform brain mapping: identi- fying from these observations the brain re- gions involved. This problem

Kaski, Samuel

27

RHAPSODY. I. STRUCTURAL PROPERTIES AND FORMATION HISTORY FROM A STATISTICAL SAMPLE OF RE-SIMULATED CLUSTER-SIZE HALOS  

SciTech Connect (OSTI)

We present the first results from the RHAPSODY cluster re-simulation project: a sample of 96 'zoom-in' simulations of dark matter halos of 10{sup 14.8{+-}0.05} h {sup -1} M {sub Sun }, selected from a 1 h {sup -3} Gpc{sup 3} volume. This simulation suite is the first to resolve this many halos with {approx}5 Multiplication-Sign 10{sup 6} particles per halo in the cluster mass regime, allowing us to statistically characterize the distribution of and correlation between halo properties at fixed mass. We focus on the properties of the main halos and how they are affected by formation history, which we track back to z = 12, over five decades in mass. We give particular attention to the impact of the formation history on the density profiles of the halos. We find that the deviations from the Navarro-Frenk-White (NFW) model and the Einasto model depend on formation time. Late-forming halos tend to have considerable deviations from both models, partly due to the presence of massive subhalos, while early-forming halos deviate less but still significantly from the NFW model and are better described by the Einasto model. We find that the halo shapes depend only moderately on formation time. Departure from spherical symmetry impacts the density profiles through the anisotropic distribution of massive subhalos. Further evidence of the impact of subhalos is provided by analyzing the phase-space structure. A detailed analysis of the properties of the subhalo population in RHAPSODY is presented in a companion paper.

Wu, Hao-Yi; Hahn, Oliver; Wechsler, Risa H.; Mao, Yao-Yuan; Behroozi, Peter S., E-mail: hywu@umich.edu [Kavli Institute for Particle Astrophysics and Cosmology, Physics Department, Stanford University, Stanford, CA 94305 (United States)

2013-02-15T23:59:59.000Z

28

The XMM-LSS survey: the Class 1 cluster sample over the extended 11 deg2 and its spatial distribution  

Science Journals Connector (OSTI)

......knowledge of the gas temperature only for converting...luminosity and temperature in the intracluster...equilibrium and a gas distribution following a...luminosity-mass relation (Sun 2012). Clusters...see text). Temperatures are measured...1999), S12 (Sun 2012) and M12...the data point distribution in Fig.-7......

N. Clerc; C. Adami; M. Lieu; B. Maughan; F. Pacaud; M. Pierre; T. Sadibekova; G. P. Smith; P. Valageas; B. Altieri; C. Benoist; S. Maurogordato; J. P. Willis

2014-01-01T23:59:59.000Z

29

The Hubble Space Telescope Cluster Supernova Survey. V. Improving the Dark-energy Constraints above z > 1 and Building an Early-type-hosted Supernova Sample  

Science Journals Connector (OSTI)

We present Advanced Camera for Surveys, NICMOS, and Keck adaptive-optics-assisted photometry of 20 Type Ia supernovae (SNe Ia) from the Hubble Space Telescope (HST) Cluster Supernova Survey. The SNe Ia were discovered over the redshift interval 0.623 z z = 1, thereby nearly doubling the statistical weight of HST-discovered SNe Ia beyond this redshift. Our detailed analysis corrects for the recently identified correlation between SN Ia luminosity and host galaxy mass and corrects the NICMOS zero point at the count rates appropriate for very distant SNe Ia. Adding these SNe improves the best combined constraint on dark-energy density, ?DE(z), at redshifts 1.0 z ? = 0.729 ± 0.014 (68% confidence level (CL) including systematic errors). For a flat wCDM model, we measure a constant dark-energy equation-of-state parameter w = –1.013+0.068 –0.073 (68% CL). Curvature is constrained to ?0.7% in the owCDM model and to ?2% in a model in which dark energy is allowed to vary with parameters w 0 and wa . Further tightening the constraints on the time evolution of dark energy will require several improvements, including high-quality multi-passband photometry of a sample of several dozen z > 1 SNe Ia. We describe how such a sample could be efficiently obtained by targeting cluster fields with WFC3 on board HST. The updated supernova Union2.1 compilation of 580 SNe is available at http://supernova.lbl.gov/Union.

N. Suzuki; D. Rubin; C. Lidman; G. Aldering; R. Amanullah; K. Barbary; L. F. Barrientos; J. Botyanszki; M. Brodwin; N. Connolly; K. S. Dawson; A. Dey; M. Doi; M. Donahue; S. Deustua; P. Eisenhardt; E. Ellingson; L. Faccioli; V. Fadeyev; H. K. Fakhouri; A. S. Fruchter; D. G. Gilbank; M. D. Gladders; G. Goldhaber; A. H. Gonzalez; A. Goobar; A. Gude; T. Hattori; H. Hoekstra; E. Hsiao; X. Huang; Y. Ihara; M. J. Jee; D. Johnston; N. Kashikawa; B. Koester; K. Konishi; M. Kowalski; E. V. Linder; L. Lubin; J. Melbourne; J. Meyers; T. Morokuma; F. Munshi; C. Mullis; T. Oda; N. Panagia; S. Perlmutter; M. Postman; T. Pritchard; J. Rhodes; P. Ripoche; P. Rosati; D. J. Schlegel; A. Spadafora; S. A. Stanford; V. Stanishev; D. Stern; M. Strovink; N. Takanashi; K. Tokita; M. Wagner; L. Wang; N. Yasuda; H. K. C. Yee; The Supernova Cosmology Project

2012-01-01T23:59:59.000Z

30

THE HUBBLE SPACE TELESCOPE CLUSTER SUPERNOVA SURVEY. V. IMPROVING THE DARK-ENERGY CONSTRAINTS ABOVE z > 1 AND BUILDING AN EARLY-TYPE-HOSTED SUPERNOVA SAMPLE  

SciTech Connect (OSTI)

We present Advanced Camera for Surveys, NICMOS, and Keck adaptive-optics-assisted photometry of 20 Type Ia supernovae (SNe Ia) from the Hubble Space Telescope (HST) Cluster Supernova Survey. The SNe Ia were discovered over the redshift interval 0.623 < z < 1.415. Of these SNe Ia, 14 pass our strict selection cuts and are used in combination with the world's sample of SNe Ia to derive the best current constraints on dark energy. Of our new SNe Ia, 10 are beyond redshift z = 1, thereby nearly doubling the statistical weight of HST-discovered SNe Ia beyond this redshift. Our detailed analysis corrects for the recently identified correlation between SN Ia luminosity and host galaxy mass and corrects the NICMOS zero point at the count rates appropriate for very distant SNe Ia. Adding these SNe improves the best combined constraint on dark-energy density, {rho}{sub DE}(z), at redshifts 1.0 < z < 1.6 by 18% (including systematic errors). For a flat {Lambda}CDM universe, we find {Omega}{sub {Lambda}} = 0.729 {+-} 0.014 (68% confidence level (CL) including systematic errors). For a flat wCDM model, we measure a constant dark-energy equation-of-state parameter w = -1.013{sup +0.068}{sub -0.073} (68% CL). Curvature is constrained to {approx}0.7% in the owCDM model and to {approx}2% in a model in which dark energy is allowed to vary with parameters w{sub 0} and w{sub a} . Further tightening the constraints on the time evolution of dark energy will require several improvements, including high-quality multi-passband photometry of a sample of several dozen z > 1 SNe Ia. We describe how such a sample could be efficiently obtained by targeting cluster fields with WFC3 on board HST. The updated supernova Union2.1 compilation of 580 SNe is available at http://supernova.lbl.gov/Union.

Suzuki, N.; Rubin, D.; Aldering, G.; Barbary, K.; Faccioli, L.; Fakhouri, H. K. [E.O. Lawrence Berkeley National Lab, Berkeley, CA 94720 (United States); Lidman, C. [Australian Astronomical Observatory, Epping, NSW 1710 (Australia); Amanullah, R.; Botyanszki, J. [Department of Physics, University of California Berkeley, Berkeley, CA 94720 (United States); Barrientos, L. F. [Departamento de Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile, Santiago (Chile); Brodwin, M. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Connolly, N. [Department of Physics, Hamilton College, Clinton, NY 13323 (United States); Dawson, K. S. [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Dey, A. [National Optical Astronomy Observatory, Tucson, AZ 85726-6732 (United States); Doi, M. [Institute of Astronomy, Graduate School of Science, University of Tokyo 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan); Donahue, M. [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Deustua, S. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Eisenhardt, P. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Ellingson, E. [Center for Astrophysics and Space Astronomy, 389 UCB, University of Colorado, Boulder, CO 80309 (United States); Fadeyev, V., E-mail: nsuzuki@lbl.gov, E-mail: rubind@berkeley.edu, E-mail: clidman@aao.gov.au [Santa Cruz Institute for Particle Physics, University of California Santa Cruz, Santa Cruz, CA 94064 (United States); Collaboration: Supernova Cosmology Project; and others

2012-02-10T23:59:59.000Z

31

A volume-limited sample of X-ray galaxy groups and clusters - II. X-ray cavity dynamics  

E-Print Network [OSTI]

We present the results of our study of a volume-limited sample (z cooling time of less than3 Gyr. New X-ray cavities are detected in three sources. We focus on the subset of sources that have a central cooling time of less than 3 Gyr, whose active galactic nucleus (AGN) duty cycle is approximately 61 percent (30/49). This rises to over 80 percent for a central cooling time of less than 0.5 Gyr. When projection effects and central radio source detection rates are considered, the actual duty cycle is probably much higher. In addition, we show that data quality strongly affects the detection rates of X-ray cavities. After calculating the cooling luminosity and cavity powers of each source with cavities, it is evident that the bubbling process induced by the central AGN has to be, on average, continuo...

Panagoulia, E K; Sanders, J S; Hlavacek-Larrondo, J

2014-01-01T23:59:59.000Z

32

Hierarchical Clustering Hierarchical Clustering  

E-Print Network [OSTI]

Distance/Proximity Matrix #12;After Merging · "How do we update the distance matrix?" C1 C4 C2 U C5 C3 ? ? ? ? ? ? ? C2 U C5C1 C1 C3 C4 C2 U C5 C3 C4 #12;Distance between two clusters · Each cluster is a set of points

Terzi, Evimaria

33

Radial Alignment of Cluster Galaxies  

E-Print Network [OSTI]

We report the discovery of a statistically significant radial alignment of cluster galaxies in a sample of 85 X-ray selected clusters observed in the Sloan Digital Sky Survey. The tendency for alignment is a robust feature of our sample and does not vary significantly with individual cluster or galaxy properties. We use dynamical arguments to show that a significant fraction of cluster galaxies should be undergoing a parametric tidal resonance that can cause their long axes to orient themselves towards the center of the cluster potential, and therefore tentatively ascribe the observed radial alignment to this dynamical effect.

M. J. Pereira; J. R. Kuhn

2005-05-25T23:59:59.000Z

34

CLUSTER CHEMISTRY  

SciTech Connect (OSTI)

Metal cluster chemistry is one of the most rapidly developing areas of inorganic and organometallic chemistry. Prior to 1960 only a few metal clusters were well characterized. However, shortly after the early development of boron cluster chemistry, the field of metal cluster chemistry began to grow at a very rapid rate and a structural and a qualitative theoretical understanding of clusters came quickly. Analyzed here is the chemistry and the general significance of clusters with particular emphasis on the cluster research within my group. The importance of coordinately unsaturated, very reactive metal clusters is the major subject of discussion.

Muetterties, Earl L.

1980-05-01T23:59:59.000Z

35

Clustering II Hierarchical Clustering  

E-Print Network [OSTI]

#12;After Merging · "How do we update the distance matrix?" C1 C4 C2 U C5 C3 ? ? ? ? ? ? ? C2 U C5C1 C1 C3 C4 C2 U C5 C3 C4 ... p1 p2 p3 p4 p9 p10 p11 p12 #12;Distance between two clusters · Each

Terzi, Evimaria

36

CLUSTER CHEMISTRY  

E-Print Network [OSTI]

atoms [9]. react. , metal carbide clusters had inguished athat we have sought is a carbide metal cluster in which theof metal atoms because reaction at the carbide site must be

Muetterties, Earl L.

2013-01-01T23:59:59.000Z

37

M/L{sub B} AND COLOR EVOLUTION FOR A DEEP SAMPLE OF M* CLUSTER GALAXIES AT z {approx} 1: THE FORMATION EPOCH AND THE TILT OF THE FUNDAMENTAL PLANE , ,  

SciTech Connect (OSTI)

We have measured velocity dispersions ({sigma}) for a sample of 36 galaxies with J < 21.2 or M{sub r} < -20.6 mag in MS 1054-03, a massive cluster of galaxies at z = 0.83. Our data are of uniformly high quality down to our selection limit, our 16 hr exposures typically yielding errors of only {delta}({sigma}) {approx} 10% for L* and fainter galaxies. By combining our measurements with data from the literature, we have 53 cluster galaxies with measured dispersions, and HST/ACS-derived sizes, colors and surface brightness. This sample is complete for the typical L* galaxy at z {approx} 1, unlike most previous z {approx} 1 cluster samples which are complete only for the massive cluster members (>10{sup 11} M{sub sun}). We find no evidence for a change in the tilt of the fundamental plane (FP). Nor do we find evidence for evolution in the slope of the color-{sigma} relation and M/L{sub B} -{sigma} relations; measuring evolution at a fixed {sigma} should minimize the impact of structural evolution found in other work. The M/L{sub B} at fixed {sigma} evolves by {Delta}log{sub 10} M/L{sub B} = -0.50 {+-} 0.03 between z = 0.83 and z = 0.02 or dlog{sub 10} M/L{sub B} = -0.60 {+-} 0.04 dz, and we find {Delta}(U - V){sub z} = -0.24 {+-} 0.02 mag at fixed {sigma} in the rest frame, matching the expected evolution in M/L{sub B} within 2.25 standard deviations. The implied formation redshift from both the color and M/L{sub B} evolution is z{sub *} = 2.0 {+-} 0.2 {+-} 0.3(sys), during the epoch in which the cosmic star formation activity peaked, with the systematic uncertainty showing the dependence of z{sub *} on the assumptions we make about the stellar populations. The lack of evolution in either the tilt of the FP or in the M/L-{sigma} and color-{sigma} relations imply that the formation epoch depends weakly on mass, ranging from z{sub *} = 2.3{sup +1.3}{sub -0.3} at {sigma} = 300 km s{sup -1} to z{sub *} = 1.7{sup +0.3}{sub -0.2} at {sigma} = 160 km s{sup -1} and implies that the initial mass function similarly varies slowly with galaxy mass.

Holden, B. P.; Illingworth, G. D. [UCO/Lick Observatories, University of California, Santa Cruz, CA 95065 (United States); Van der Wel, A. [Max-Planck Institute for Astronomy, Koenigstuhl 17, D-69117, Heidelberg (Germany); Kelson, D. D. [Observatories of the Carnegie Institution of Washington, Pasadena, CA 91101 (United States); Franx, M., E-mail: holden@ucolick.or, E-mail: gdi@ucolick.or, E-mail: vdwel@mpia.d, E-mail: kelson@obs.carnegiescience.ed, E-mail: franx@strw.leidenuniv.n [Sterrewacht Leiden, P.O. Box 9513, 2300 RA, Leiden (Netherlands)

2010-11-20T23:59:59.000Z

38

The Clustering of the SDSS DR7 Main Galaxy Sample I: A 4 per cent Distance Measure at z=0.15  

E-Print Network [OSTI]

We create a sample of spectroscopically identified galaxies with $z Survey (SDSS) Data Release 7, covering 6813 deg$^2$. Galaxies are chosen to sample the highest mass haloes, with an effective bias of 1.5, allowing us to construct 1000 mock galaxy catalogs (described in Paper II), which we use to estimate statistical errors and test our methods. We use an estimate of the gravitational potential to "reconstruct" the linear density fluctuations, enhancing the Baryon Acoustic Oscillation (BAO) signal in the measured correlation function and power spectrum. Fitting to these measurements, we determine $D_{V}(z_{\\rm eff}=0.15) = (664\\pm25)(r_d/r_{d,{\\rm fid}})$ Mpc; this is a better than 4 per cent distance measurement. This "fills the gap" in BAO distance ladder between previously measured local and higher redshift measurements, and affords significant improvement in constraining the properties of dark energy. Combining our measurement with other BAO measurements from BOSS and...

Ross, Ashley J; Howlett, Cullan; Percival, Will J; Burden, Angela; Manera, Marc

2014-01-01T23:59:59.000Z

39

CLUSTER CHEMISTRY  

E-Print Network [OSTI]

Advanced Inorganic Chemistry, 11 Wiley Huetterties and C. M.Submitted to the Journal of Organometallic ChemistryCLUSTER CHEMISTRY Earl L. Muetterties TWO-WEEK LOAN COPY May

Muetterties, Earl L.

2013-01-01T23:59:59.000Z

40

Cooling and Clusters: When Is Heating Needed?  

E-Print Network [OSTI]

There are (at least) two unsolved problems concerning the current state of the thermal gas in clusters of galaxies. The first is identifying the source of the heating which offsets cooling in the centers of clusters with short cooling times (the ``cooling flow'' problem). The second is understanding the mechanism which boosts the entropy in cluster and group gas. Since both of these problems involve an unknown source of heating it is tempting to identify them with the same process, particular since AGN heating is observed to be operating at some level in a sample of well-observed ``cooling flow'' clusters. Here we show, using numerical simulations of cluster formation, that much of the gas ending up in clusters cools at high redshift and so the heating is also needed at high-redshift, well before the cluster forms. This indicates that the same process operating to solve the cooling flow problem may not also resolve the cluster entropy problem.

Greg L. Bryan; G. Mark Voit

2005-02-22T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

The fundamental plane of clusters of galaxies: a quest for understanding cluster dynamics and morphology  

E-Print Network [OSTI]

We discuss implications of the fundamental plane parameters of clusters of galaxies derived from combined optical and X-ray data of a sample of 78 nearby clusters. In particular, we investigate the dependence of these parameters on the dynamical state of the cluster. We introduce a new concept of allocation of the fundamental plane of clusters derived from their intrinsic morphological properties, and put some theoretical implications of the existence of a fundamental plane into perspective.

Christoph Fritsch; Thomas Buchert

1999-03-10T23:59:59.000Z

42

Clusters and Superclusters in the Sloan Digital Sky Survey  

E-Print Network [OSTI]

Two-dimensional high-resolution density field of galaxies of the Early Data Release of the Sloan Digital Sky Survey with a smoothing lengths 0.8 h^{-1} Mpc is applied to extract clusters of galaxies, and a low-resolution field with smoothing lengths 10^{-1} Mpc to extract superclusters of galaxies. We compare properties of density field clusters and superclusters with Abell clusters, and superclusters found on the basis of Abell clusters. We found that clusters in high-density environment have a luminosity a factor of about 5 higher than in low-density environment. There exists a large anisotropy between the SDSS Northern and Southern sample in the properties of clusters and superclusters: most luminous clusters and superclusters in the Northern sample are a factor of 2 more luminous than the respective systems in the Southern sample.

J. Einasto; G. H"utsi; M. Einasto; E. Saar; D. L. Tucker; V. M"uller; P. Hein"am"aki; S. S. Allam

2002-12-13T23:59:59.000Z

43

Cluster-impact fusion  

Science Journals Connector (OSTI)

We present a model for the cluster-impact-fusion experiments of Buehler, Friedlander, and Friedman, Calculated fusion rates as a function of bombarding energy for constant cluster size agree well with experiment. The dependence of the fusion rate on cluster size at fixed bombarding energy is explained qualitatively. The role of correlated, coherent collisions in enhanced energy loss by clusters is emphasized.

P. M. Echenique; J. R. Manson; R. H. Ritchie

1990-03-19T23:59:59.000Z

44

Which young clusters/associations are we missing today?  

E-Print Network [OSTI]

Currently clusters/associations of stars are mainly detected as surface density enhancements relative to the background field. While clusters form, their surface density increases. It likely decreases again at the end of the star formation process when the system expands as a consequence of gas expulsion. Therefore the surface density of a single cluster can change considerably in young clusters/associations during the first 20 Myr of their development. We investigate the effect of the gas expulsion on the detectability of clusters/associations typical for the solar neighborhood, where the star formation efficiency is 4 Myr only the most massive clusters are identified, while systems with initially M_c < 3 000 M(sun) are missing. The temporal development of stellar properties is usually determined by observing clusters of different ages. The potentially strong inhomogeneity of the cluster sample makes this methods highly questionable. However, GAIA could provide the means to rectify this situation as it w...

Pfalzner, Susanne; Xiang, Mai

2015-01-01T23:59:59.000Z

45

THE STRUCTURE OF 2MASS GALAXY CLUSTERS  

SciTech Connect (OSTI)

We use a sample of galaxies from the Two Micron All Sky Survey Extended Source Catalog to refine a matched filter method of finding galaxy clusters that takes into account each galaxy's position, magnitude, and redshift if available. The matched filter postulates a radial density profile, luminosity function, and line-of-sight velocity distribution for cluster galaxies. We use this method to search for clusters in the galaxy catalog, which is complete to an extinction-corrected K-band magnitude of 13.25 and has spectroscopic redshifts for roughly 40% of the galaxies, including nearly all brighter than K = 11.25. We then use a stacking analysis to determine the average luminosity function, radial distribution, and velocity distribution of cluster galaxies in several richness classes, and use the results to update the parameters of the matched filter before repeating the cluster search. We also investigate the correlations between a cluster's richness and its velocity dispersion and core radius using these relations to refine priors that are applied during the cluster search process. After the second cluster search iteration, we repeat the stacking analysis. We find a cluster galaxy luminosity function that fits a Schechter form, with parameters M{sub K*} - 5log h = -23.64 {+-} 0.04 and {alpha} = -1.07 {+-} 0.03. We can achieve a slightly better fit to our luminosity function by adding a Gaussian component on the bright end to represent the brightest cluster galaxy population. The radial number density profile of galaxies closely matches a projected Navarro-Frenk-White profile at intermediate radii, with deviations at small radii due to well-known cluster centering issues and outside the virial radius due to correlated structure. The velocity distributions are Gaussian in shape, with velocity dispersions that correlate strongly with richness.

Blackburne, Jeffrey A.; Kochanek, Christopher S. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States)

2012-01-01T23:59:59.000Z

46

Identifying Customer Profiles in Power Load Time Series Using Spectral Clustering  

Science Journals Connector (OSTI)

An application of multiway spectral clustering with out-of-sample extensions towards clustering time series is presented. The data correspond to power load time series acquired from substations in the ... eigenve...

Carlos Alzate; Marcelo Espinoza; Bart De Moor…

2009-01-01T23:59:59.000Z

47

Correspondence Clustering: An Approach to Cluster Multiple Related Spatial Datasets  

E-Print Network [OSTI]

Correspondence Clustering: An Approach to Cluster Multiple Related Spatial Datasets Vadeerat spatial datasets. This capability is important for change analysis and contrast mining. In this paper spatial datasets by maximizing cluster interestingness and correspondence between clusters derived from

Eick, Christoph F.

48

The richness dependence of galaxy cluster correlations: Results from a redshift survey of rich APM clusters  

E-Print Network [OSTI]

We analyse the spatial clustering properties of a new catalogue of very rich galaxy clusters selected from the APM Galaxy Survey. These clusters are of comparable richness and space density to Abell Richness Class $\\geq 1$ clusters, but selected using an objective algorithm from a catalogue demonstrably free of artificial inhomogeneities. Evaluation of the two-point correlation function $\\xi_{cc}(r)$ for the full sample and for richer subsamples reveals that the correlation amplitude is consistent with that measured for lower richness APM clusters and X-ray selected clusters. We apply a maxmimum likelihood estimator to find the best fitting slope and amplitude of a power law fit to $\\xi_{cc}(r)$, and to estimate the correlation length $r_{0}$ (the value of $r$ at which $\\xi_{cc}(r)$ is equal to unity). For clusters with a mean space density of $1.6\\times 10^{-6}\\hmpccc$ (equivalent to the space density of Abell Richness $\\geq 2$ clusters), we find $r_{0}=21.3^{+11.1}_{-9.3} \\hmpc$ (95% confidence limits). This is consistent with the weak richness dependence of $\\xi_{cc}(r)$ expected in Gaussian models of structure formation. In particular, the amplitude of $\\xi_{cc}(r)$ at all richnesses matches that of $\\xi_{cc}(r)$ for clusters selected in N-Body simulations of a low density Cold Dark Matter model.

Rupert A. C. Croft; Gavin B. Dalton; George Efstathiou; Will Sutherland; Steve Maddox

1997-01-09T23:59:59.000Z

49

Intergalactic Globular Clusters  

E-Print Network [OSTI]

We confirm and extend our previous detection of a population of intergalactic globular clusters in Abell 1185, and report the first discovery of an intergalactic globular cluster in the nearby Virgo cluster of galaxies. The numbers, colors and luminosities of these objects can place constraints on their origin, which in turn may yield new insights to the evolution of galaxies in dense environments.

Michael J. West; Patrick Cote; Henry C. Ferguson; Michael D. Gregg; Andres Jordan; Ronald O. Marzke; Nial R. Tanvir; Ted von Hippel

2003-09-23T23:59:59.000Z

50

NREL: Process Development and Integration Laboratory - Silicon Cluster Tool  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Silicon Cluster Tool Capabilities Silicon Cluster Tool Capabilities Photo of a cylindrical metal chamber surrounded by numerous other smaller cylindrical or rectangular chambers. Each tool has several flanges and is typically held within a metal frame or rack. A computer is on a table in front of a cabinet of electronic equipment. Silicon cluster tool in the Process Development and Integration Laboratory. The Silicon cluster tool within the Process Development and Integration Laboratory is a 10-port cluster tool designed by the National Renewable Energy Laboratory (NREL) and manufactured by MVSystems. It handles standard 157-mm x 157-mm samples introduced into the central 10-6 torr vacuum chamber via a load lock. From there, a robotic arm moves samples from one chamber to another within the cluster tool. Contact Qi Wang for more

51

ChaMP Serendipitous Galaxy Cluster Survey  

SciTech Connect (OSTI)

We present a survey of serendipitous extended X-ray sources and optical cluster candidates from the Chandra Multi-wavelength Project (ChaMP). Our main goal is to make an unbiased comparison of X-ray and optical cluster detection methods. In 130 archival Chandra pointings covering 13 square degrees, we use a wavelet decomposition technique to detect 55 extended sources, of which 6 are nearby single galaxies. Our X-ray cluster catalog reaches a typical flux limit of about {approx} 10{sup -14} erg s{sup -1} cm{sup -2}, with a median cluster core radius of 21''. For 56 of the 130 X-ray fields, we use the ChaMP's deep NOAO/4m MOSAIC g', r', and i' imaging to independently detect cluster candidates using a Voronoi tessellation and percolation (VTP) method. Red-sequence filtering decreases the galaxy fore/background contamination and provides photometric redshifts to z {approx} 0.7. From the overlapping 6.1 square degree X-ray/optical imaging, we find 115 optical clusters (of which 11% are in the X-ray catalog) and 28 X-ray clusters (of which 46% are in the optical VTP catalog). The median redshift of the 13 X-ray/optical clusters is 0.41, and their median X-ray luminosity (0.5-2 keV) is L{sub X} = (2.65 {+-} 0.19) x 10{sup 43} ergs s{sup -1}. The clusters in our sample that are only detected in our optical data are poorer on average ({approx} 4{sigma}) than the X-ray/optically matched clusters, which may partially explain the difference in the detection fractions.

Barkhouse, Wayne A.; Green, P.J.; Vikhlinin, A.; Kim, D.-W.; Perley, D.; Cameron, R.; Silverman, J.; Mossman, A.; Burenin, R.; Jannuzi, B.T.; Kim, M.; Smith, M.G.; Smith,; Tananbaum, H.; Wilkes, B.J.; /Harvard-Smithsonian Ctr. Astrophys. /UC, Berkeley, Astron. Dept. /SLAC /Garching, Max Planck Inst., MPE /Moscow, Space Res. Inst. /NOAO, Tucson

2006-04-03T23:59:59.000Z

52

New Candidate Massive Clusters from 2MASS  

E-Print Network [OSTI]

Massive stars are important for the evolution of the interstellar medium. The detailed study of their properties (such as mass loss, rotation, magnetic fields) is enormously facilitated by samples of these objects in young massive galactic star clusters. Using 2MASS we have searched for so far unknown candidates of red supergiant clusters along the Galactic Plane. Utilising deep high resolution UKIDSS GPS and VISTA VVV data to study colour-magnitude diagrams, we uncover six new massive cluster candidates in the inner Galaxy. If spectroscopically confirmed as real clusters, two of them could be part of the Scutum-Complex. One cluster candidate has a number of potential red supergiant members comparable to RSGC1 and 3. Our investigation of UKIDSS data reveals for the first time the main sequence of the massive cluster RSGC2. The stars of the sequence show an increased projected density at the same position as the known red supergiants in the cluster and have E(J-K)=1.6mag. This either indicates an unusual extin...

Froebrich, D

2013-01-01T23:59:59.000Z

53

Cluster probes of dark energy clustering  

Science Journals Connector (OSTI)

Cluster abundances are oddly insensitive to canonical early dark energy. Early dark energy with sound speed equal to the speed of light cannot be distinguished from a quintessence model with the equivalent expansion history for zdark energy density, despite the different early growth rate. However, cold early dark energy, with a sound speed much smaller than the speed of light, can give a detectable signature. Combining cluster abundances with cosmic microwave background (CMB) power spectra can determine the early dark energy fraction to 0.3% and distinguish a true sound speed of 0.1 from 1 at 99% confidence. We project constraints on early dark energy from the Euclid cluster survey, as well as the Dark Energy Survey, using both current and projected Planck CMB data, and assess the impact of cluster mass systematics. We also quantify the importance of dark energy perturbations, and the role of sound speed during a crossing of w=-1.

Stephen A. Appleby; Eric V. Linder; Jochen Weller

2013-08-29T23:59:59.000Z

54

The Apm Galaxy Survey IV: Redshifts of Rich Clusters of Galaxies  

E-Print Network [OSTI]

We present redshifts for a sample of 229 clusters selected from the APM Galaxy Survey, 189 of which are new redshift determinations. Non-cluster galaxy redshifts have been rejected from this sample using a likelihood ratio test based on the projected and apparent magnitude distributions of the cluster fields. We test this technique using cluster fields in which redshifts have been measured for more than 10 galaxies. Our redshift sample is nearly complete and has been used in previous papers to study the three dimensional distribution of rich clusters of galaxies. 157 of the clusters in our sample are listed in the Abell catalogue or supplement, and the remainder are new cluster identifications.

G. B. Dalton; G. Efstathiou; S. J. Maddox; W. J. Sutherland

1993-11-16T23:59:59.000Z

55

Cluster-impact fusion  

Science Journals Connector (OSTI)

Deuteron-deuteron fusion, detected via the 3-MeV protons produced, is shown to occur when singly charged clusters of 25 to 1300 D2O molecules, accelerated to 200 to 325 keV, impinge on TiD targets. The energy and cluster-size dependence of the fusion rate are discussed. The fusion events are shown to originate from the cluster-ion impacts rather than from D+ or D2O+ ions in the beam. The observed rates may be correlated with the compressions and high energy densities created in collision spikes by cluster-ion impacts.

R. J. Beuhler; G. Friedlander; L. Friedman

1989-09-18T23:59:59.000Z

56

Accelerated Fuzzy Clustering.  

E-Print Network [OSTI]

??Clustering algorithms are a primary tool in data analysis, facilitating the discovery of groups and structure in unlabeled data. They are used in a wide… (more)

Parker, Jonathon Karl

2013-01-01T23:59:59.000Z

57

Heating Rate Profiles in Galaxy Clusters  

E-Print Network [OSTI]

In recent years evidence has accumulated suggesting that the gas in galaxy clusters is heated by non-gravitational processes. Here we calculate the heating rates required to maintain a physically motived mass flow rate, in a sample of seven galaxy clusters. We employ the spectroscopic mass deposition rates as an observational input along with temperature and density data for each cluster. On energetic grounds we find that thermal conduction could provide the necessary heating for A2199, Perseus, A1795 and A478. However, the suppression factor, of the clasical Spitzer value, is a different function of radius for each cluster. Based on the observations of plasma bubbles we also calculate the duty cycles for each AGN, in the absence of thermal conduction, which can provide the required energy input. With the exception of Hydra-A it appears that each of the other AGNs in our sample require duty cycles of roughly $10^{6}-10^{7}$ yrs to provide their steady-state heating requirements. If these duty cycles are unrealistic, this may imply that many galaxy clusters must be heated by very powerful Hydra-A type events interspersed between more frequent smaller-scale outbursts. The suppression factors for the thermal conductivity required for combined heating by AGN and thermal conduction are generally acceptable. However, these suppression factors still require `fine-tuning` of the thermal conductivity as a function of radius. As a consequence of this work we present the AGN duty cycle as a cooling flow diagnostic.

Edward C. D. Pope; Georgi Pavlovski; Christian R. Kaiser; Hans Fangohr

2006-01-05T23:59:59.000Z

58

Vectorized Cluster Search  

E-Print Network [OSTI]

Contrary to conventional wisdom, the construction of clusters on a lattice can easily be vectorized, namely over each ``generation'' in a breadth first search. This applies directly to, e.g., the {\\it single cluster} variant of the Swendsen-Wang algorithm. On a Cray Y-MP, total CPU time was reduced by a factor 3.5 -- 7 in actual applications.

Hans Gerd Evertz

1992-04-08T23:59:59.000Z

59

SciCloneSciClone A Cluster of Clusters forA Cluster of Clusters for  

E-Print Network [OSTI]

Enable cross-disciplinary graduate programs ·· Provide research facility for scientific computingProvide research facility for scientific computing ­­ ""SciCloneSciClone ClusterCluster"" (Science (LAM, ATLAS, NAMD, etc.)Tool development (LAM, ATLAS, NAMD, etc.) ·· Instruction (classes, graduate

Lewis, Robert Michael

60

Symmetry and cluster magnetism  

Science Journals Connector (OSTI)

Three possible isomers of 13-atom iron clusters are studied using local-density-functional methods that allow the spin of the cluster to be determined self-consistently. The ground state is the icosahedral structure. It has the greatest magnetic moment because of increased symmetry-required orbital degeneracy for electrons of different spins.

Brett I. Dunlap

1990-05-15T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Energy Landscapes of Planar Colloidal Clusters  

E-Print Network [OSTI]

Energy Landscapes of Planar Colloidal Clusters John W. R. Morgan,a and David J. Wales?b Received Xth XXXXXXXXXX 20XX, Accepted Xth XXXXXXXXX 20XX First published on the web Xth XXXXXXXXXX 20XX DOI: 10.1039/b000000x A short-ranged pairwise Morse... potential is used to model colloidal clusters with planar morphologies. Potential and free energy global minima as well as rearrangement paths, obtained by basin-hopping global optimisation and discrete path sampling, are characterised. The potential...

Morgan, John W. R.; Wales, David J.

2014-07-24T23:59:59.000Z

62

Best Clustering Configuration Metrics: Towards Multiagent Based Clustering  

E-Print Network [OSTI]

with algorithms to conduct clustering operations or to validate the output from clus- tering algorithms, some

Atkinson, Katie

63

Ram Pressure Stripping in Clusters and Groups  

E-Print Network [OSTI]

Ram pressure stripping is an important process in the evolution of both dwarf galaxies and large spirals. Large spirals are severely stripped in rich clusters and may be mildly stripped in groups. Dwarf galaxies can be severely stripped in both clusters and groups. A model is developed that describes the stripping of a satellite galaxy's outer H \\textsc{i} disk and hot galactic halo. The model can be applied to a wide range of environments and satellite galaxy masses. Whether ram pressure stripping of the outer disk or hot galactic halo occurs is found to depend primarily on the ratio of the satellite galaxy mass to the mass of the host group or cluster. How the effectiveness of ram pressure stripping depends on the density of the inter-group gas, the dark matter halo concentrations, and the scale lengths and masses of the satellite components is explored. The predictions of the model are shown to be well matched to H \\textsc{i} observations of spirals in a sample of nearby clusters. The model is used to predict the range of H \\textsc{i} gas fractions a satellite of mass $M_{v,sat}$ can lose orbiting in a cluster of mass $M_{v,gr}$.

J. A. Hester

2006-10-03T23:59:59.000Z

64

CMB-Cluster Lensing  

E-Print Network [OSTI]

Clusters of galaxies are powerful cosmological probes, particularly if their masses can be determined. One possibility for mass determination is to study the cosmic microwave background (CMB) on small angular scales and observe deviations from a pure gradient due to lensing of massive clusters. I show that, neglecting contamination, this technique has the power to determine cluster masses very accurately, in agreement with estimates by Seljak and Zaldarriaga (1999). However, the intrinsic small scale structure of the CMB significantly degrades this power. The resulting mass constraints are useless unless one imposes a prior on the concentration parameter c. With even a modest prior on c, an ambitious CMB experiment (0.5' resolution and 1 microK per pixel) could determine masses of high redshift (z>0.5) clusters with ~ 30% accuracy.

Scott Dodelson

2004-02-12T23:59:59.000Z

65

Magnetism of carbon clusters  

Science Journals Connector (OSTI)

The ?-electron ring current magnetic susceptibilities and endohedral chemical shifts of the fullerenes are calculated with the London theory. The diamagnetism calculated for the fullerenes that have been characterized to date does not show a monotonic increase toward the graphite value. By carrying out calculations on high-symmetry giant fullerenes (Cn) in the size regime 100magnetic susceptibility of graphite on a per carbon basis. Endohedral chemical shifts are predicted to be invariant to cluster size, but subject to the quantum size effects seen in smaller fullerenes and metallic clusters. The fullerenes are different from the metallic clusters because the finite band gap in conjugated carbon compounds allows the diamagnetic term to dominate at large cluster size. The experimentally observed decrease in nanotube material diamagnetism with temperature is attributed to the increased importance of the Van Vleck term due to finite-temperature effects.

R. C. Haddon and Alfredo Pasquarello

1994-12-01T23:59:59.000Z

66

Small Community Wastewater Cluster Systems  

E-Print Network [OSTI]

Small Community Wastewater Cluster Systems Don Jones, Jacqui Bauer, Richard Wise, and Alan Dunn* ID-265 #12;Small Community Wastewater Cluster Systems ID-265 2 It is the policy of the Purdue University Community Wastewater Cluster Systems ID-265 3 Small Community Wastewater Cluster Systems Table of Contents

Holland, Jeffrey

67

The 2dF Galaxy Redshift Survey: The clustering of galaxy groups  

E-Print Network [OSTI]

We measure the clustering of galaxy groups in the 2dFGRS Percolation-Inferred Galaxy Group (2PIGG) catalogue. The 2PIGG sample has 29,000 groups with at least two members. The clustering amplitude of the full 2PIGG catalogue is weaker than that of 2dFGRS galaxies, in agreement with theoretical predictions. We have subdivided the 2PIGG catalogue into samples that span a factor of 25 in median total luminosity. Our correlation function measurements span an unprecedented range of clustering strengths, connecting the regimes probed by groups fainter than L* galaxies and rich clusters. There is a steady increase in clustering strength with group luminosity; the most luminous groups are ten times more strongly clustered than the full 2PIGG catalogue. We demonstrate that the 2PIGG results are in very good agreement with the clustering of groups expected in the LCDM model.

Nelson D. Padilla; C. M. Baugh; V. R. Eke; P. Norberg; S. Cole; C. S. Frenk; D. J. Croton; I. K. Baldry; J. Bland-Hawthorn; T. Bridges; R. Cannon; M. Colless; C. Collins; W. Couch; G. Dalton; R. De Propris; S. P. Driver; G. Efstathiou; R. S. Ellis; K. Glazebrook; C. Jackson; O. Lahav; I. Lewis; S. Lumsden; S. Maddox; D. Madgwick; J. A. Peacock; B. A. Peterson; W. Sutherland; K. Taylor.

2004-07-12T23:59:59.000Z

68

Star Cluster Ecology: VII The evolution of young dense star clusters containing primordial binaries  

E-Print Network [OSTI]

We study the first 100Myr of the evolution of isolated star clusters initially containing 144179 stars, including 13107 (10%) primordial hard binaries. Our calculations include the effects of both stellar and binary evolution. Gravitational interactions among the stars are computed by direct N-body integration using high precision GRAPE-6 hardware. The evolution of the core radii and central concentrations of our simulated clusters are compared with the observed sample of young (about 100Myr) star clusters in the large Magellanic cloud. Even though our simulations start with a rich population of primordial binaries, core collapse during the early phase of the cluster evolution is not prevented. Throughout the simulations, the fraction of binaries remains roughly constant (about 10%). Due to the effects of mass segregation the mass function of intermediate-mass main-sequence stars becomes as flat as $\\alpha=-1.8$ in the central part of the cluster (where the initial Salpeter mass function had $\\alpha=-2.35$). About 6--12% of the neutron stars were retained in our simulations; the fraction of retained black holes is 40--70%. In each simulation about three neutron stars become members of close binaries with a main-sequence companion. Such a binary will eventually become an x-ray binary, when the main-sequence star starts to fill its Roche lobe. Black holes are found more frequently in binaries; in each simulated cluster we find about 11 potential x-ray binaries containing a black hole. Abstract abbreviated....

Simon Portegies Zwart; Steve McMillan; Jun Makino

2006-09-27T23:59:59.000Z

69

The orbital motion of the Quintuplet cluster - a common origin for the Arches and Quintuplet clusters?  

E-Print Network [OSTI]

We investigate the orbital motion of the Quintuplet cluster near the Galactic center with the aim of constraining formation scenarios of young, massive star clusters in nuclear environments. Three epochs of adaptive optics high-angular resolution imaging with Keck/NIRC2 and VLT/NACO were obtained over a time baseline of 5.8 years, delivering an astrometric accuracy of 0.5-1 mas/yr. Proper motions were derived in the cluster reference frame and were used to distinguish cluster members from the majority of field stars. Fitting the cluster and field proper motion distributions with 2D gaussian models, we derive the orbital motion of the cluster for the first time. The Quintuplet is moving with a 2D velocity of 132 +/- 15 km/s with respect to the field along the Galactic plane, which yields a 3D orbital velocity of 167 +/- 15 km/s when combined with the previously known radial velocity. From a sample of 119 stars measured in three epochs, we derive an upper limit to the velocity dispersion in the core of the Quin...

Stolte, Andrea; Morris, Mark R; Ghez, Andrea M; Brandner, Wolfgang; Lu, Jessica R; Clarkson, William I; Habibi, Maryam; Matthews, Keith

2014-01-01T23:59:59.000Z

70

Anthrax Sampling  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Anthrax Anthrax Sampling and Decontamination: Technology Trade-Offs Phillip N. Price, Kristina Hamachi, Jennifer McWilliams, and Michael D. Sohn Environmental Energy Technologies Division Lawrence Berkeley National Laboratory Berkeley CA 94720 September 12, 2008 This work was supported by the Office of Science, Office of High Energy Physics, Homeland Security under the U.S. Department of Energy under Contract No. DE-AC02-05CH1123. Contents 1 Executive Summary 3 1.1 How much sampling is needed to decide if a building is safe? . . . . . . . 3 1.1.1 Sampling Nomogram . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.2 How many characterization samples should be taken? . . . . . . . . . . . 7 1.3 What decontamination method should be used? . . . . . . . . . . . . . . . 7 1.4 Post-decontamination sampling . . . . . . . . . . . . . . . . . . . . . . . . 8 1.5 What are rules of thumb for cost and effort? . . . . . . . . . . . .

71

E-Print Network 3.0 - advanced cervix cancer Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

cancer Search Powered by Explorit Topic List Advanced Search Sample search results for: advanced cervix cancer Page: << < 1 2 3 4 5 > >> 1 Tissue Classification using Cluster...

72

E-Print Network 3.0 - advanced cancer cervix Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Powered by Explorit Topic List Advanced Search Sample search results for: advanced cancer cervix Page: << < 1 2 3 4 5 > >> 1 Tissue Classification using Cluster Features for...

73

The structure of nickel clusters  

SciTech Connect (OSTI)

The reactions of nickel clusters with ammonia and with water are used to probe cluster geometrical structure. Ammonia uptake experiments allow the determination of the number of preferred binding sites on cluster surfaces. This number shows pronounced minima in the 50- to 116- atom size range for many of the cluster sizes that appear as magic numbers in mass spectra of rare gas clusters. Since these magic numbers arise from closings of shells and subshells of the Mackay icosahedra, the correlation suggests that ammoniated nickel clusters in this size region also have icosahedral structure. Similar structure is found for ammoniated clusters smaller than {similar to}30 atoms, but is not seen for room temperature clusters in the vicinity of the third shell closing at 147 atoms. Icosahedral features do appear for the larger clusters at elevated temperatures. For many clusters above 50 atoms, prolonged exposure to ammonia causes a conversion from the icosahedral structure to some other structure that binds more ammonia molecules, and often the two structures are seen together. The equilibrium reaction of a single water molecule with the bare clusters probes the strength of the cluster--water bond. Enhanced water adsorption is often seen for clusters one atom larger than those showing minima in ammonia uptake, suggesting that these bare clusters likewise have icosahedral structure. The reasons for minima in ammonia uptake and maxima in water binding are discussed.

Parks, E.K.; Winter, B.J.; Klots, T.D.; Riley, S.J. (Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439 (US))

1991-02-01T23:59:59.000Z

74

SED, Metallicity and Age of Halo Globular Clusters in M33  

E-Print Network [OSTI]

In this paper we study the properties of ten halo globular clusters in the nearby spiral galaxy M33. CCD images of M33 were obtained as a part of the BATC Colour Survey of the sky in 13 intermediate-band filters from 3800 to 10000{\\AA}. By aperture photometry, we obtain the spectral energy distributions (SEDs) of these globular clusters. We estimate the ages of our sample clusters by comparing the photometry of each object with theoretical stellar population synthesis models for different values of metallicity. Our results suggest that eight of the ten sample halo globular clusters have ``intermediate'' ages, i.e. between 1 and 8 Gyrs.

Ma, J; Chen, J; Wu, H; Jiang, Z; Xue, S; Zhu, J; Ma, Jun; Zhou, Xu; Chen, Jiansheng; Wu, Hong; Jiang, Zhaoji; Xue, Suijian; Zhu, Jin

2002-01-01T23:59:59.000Z

75

Thermodynamics of clusterized matter  

E-Print Network [OSTI]

Thermodynamics of clusterized matter is studied in the framework of statistical models with non-interacting cluster degrees of freedom. At variance with the analytical Fisher model, exact Metropolis simulation results indicate that the transition from homogeneous to clusterized matter lies along the $\\rho=\\rho_0$ axis at all temperatures and the limiting point of the phase diagram is not a critical point even if the surface energy vanishes at this point. Sensitivity of the inferred phase diagram to the employed statistical framework in the case of finite systems is discussed by considering the grand-canonical and constant-pressure canonical ensembles. A Wigner-Seitz formalism in which the fragment charge is neutralized by an uniform electron distribution allows to build the phase diagram of neutron star matter.

Ad. R. Raduta; F. Gulminelli

2009-02-28T23:59:59.000Z

76

Optical and X-ray clusters as tracers of the supercluster-void network. III Distribution of Abell and APM clusters  

E-Print Network [OSTI]

We present a comparison of Abell and APM clusters of galaxies as tracers of the large scale structure of the Universe. We investigate selection functions of both cluster catalogs. We show that the supercluster-void network can be traced with both cluster samples; the network has a well-defined period of ~120 h^{-1} Mpc. We calculate the correlation function and the power spectrum for Abell and APM cluster samples. The APM cluster sample with measured redshifts covers a small volume which contains only a few very rich superclusters that surround one void and have exceptionally large mutual separations. Due to this property the maximum of the power spectrum of APM clusters with measured velocities is shifted to larger scales than the corresponding feature in the power spectrum of Abell clusters. We conclude that the APM sample is not representative for the large-scale structure as a whole due to the small space coverage. We present a catalog of superclusters of galaxies, based on APM clusters up to a redshift z_{lim}=0.13.

M. Einasto; J. Einasto; E. Tago; H. Andernach; G. B. Dalton; V. M"uller

2000-12-29T23:59:59.000Z

77

Sampling apparatus  

DOE Patents [OSTI]

A sampling apparatus is provided for sampling substances from solid surfaces. The apparatus includes first and second elongated tubular bodies which telescopically and sealingly join relative to one another. An absorbent pad is mounted to the end of a rod which is slidably received through a passageway in the end of one of the joined bodies. The rod is preferably slidably and rotatably received through the passageway, yet provides a selective fluid tight seal relative thereto. A recess is formed in the rod. When the recess and passageway are positioned to be coincident, fluid is permitted to flow through the passageway and around the rod. The pad is preferably laterally orientable relative to the rod and foldably retractable to within one of the bodies. A solvent is provided for wetting of the pad and solubilizing or suspending the material being sampled from a particular surface. 15 figs.

Gordon, N.R.; King, L.L.; Jackson, P.O.; Zulich, A.W.

1989-07-18T23:59:59.000Z

78

Sampling apparatus  

DOE Patents [OSTI]

A sampling apparatus is provided for sampling substances from solid surfaces. The apparatus includes first and second elongated tubular bodies which telescopically and sealingly join relative to one another. An absorbent pad is mounted to the end of a rod which is slidably received through a passageway in the end of one of the joined bodies. The rod is preferably slidably and rotatably received through the passageway, yet provides a selective fluid tight seal relative thereto. A recess is formed in the rod. When the recess and passageway are positioned to be coincident, fluid is permitted to flow through the passageway and around the rod. The pad is preferably laterally orientable relative to the rod and foldably retractable to within one of the bodies. A solvent is provided for wetting of the pad and solubilizing or suspending the material being sampled from a particular surface.

Gordon, Norman R. (Kennewick, WA); King, Lloyd L. (Benton, WA); Jackson, Peter O. (Richland, WA); Zulich, Alan W. (Bel Air, MD)

1989-01-01T23:59:59.000Z

79

REVISITING SCALING RELATIONS FOR GIANT RADIO HALOS IN GALAXY CLUSTERS  

SciTech Connect (OSTI)

Many galaxy clusters host megaparsec-scale radio halos, generated by ultrarelativistic electrons in the magnetized intracluster medium. Correlations between the synchrotron power of radio halos and the thermal properties of the hosting clusters were established in the last decade, including the connection between the presence of a halo and cluster mergers. The X-ray luminosity and redshift-limited Extended GMRT Radio Halo Survey provides a rich and unique dataset for statistical studies of the halos. We uniformly analyze the radio and X-ray data for the GMRT cluster sample, and use the new Planck Sunyaev-Zel'dovich (SZ) catalog to revisit the correlations between the power of radio halos and the thermal properties of galaxy clusters. We find that the radio power at 1.4 GHz scales with the cluster X-ray (0.1-2.4 keV) luminosity computed within R{sub 500} as P{sub 1.4}?L{sup 2.1±0.2}{sub 500}. Our bigger and more homogenous sample confirms that the X-ray luminous (L{sub 500} > 5 × 10{sup 44} erg s{sup –1}) clusters branch into two populations—radio halos lie on the correlation, while clusters without radio halos have their radio upper limits well below that correlation. This bimodality remains if we excise cool cores from the X-ray luminosities. We also find that P{sub 1.4} scales with the cluster integrated SZ signal within R{sub 500}, measured by Planck, as P{sub 1.4}?Y{sup 2.05±0.28}{sub 500}, in line with previous findings. However, contrary to previous studies that were limited by incompleteness and small sample size, we find that 'SZ-luminous' Y{sub 500} > 6 × 10{sup –5} Mpc{sup 2} clusters show a bimodal behavior for the presence of radio halos, similar to that in the radio-X-ray diagram. Bimodality of both correlations can be traced to clusters dynamics, with radio halos found exclusively in merging clusters. These results confirm the key role of mergers for the origin of giant radio halos, suggesting that they trigger the relativistic particle acceleration.

Cassano, R.; Brunetti, G.; Venturi, T.; Kale, R. [INAF/IRA, via Gobetti 101, I-40129 Bologna (Italy); Ettori, S. [INAF/Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna (Italy); Giacintucci, S. [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Pratt, G. W. [Laboratoire AIM, IRFU/Service dAstrophysique-CEA/DSM-CNRS-Université Paris Diderot, Bât. 709, CEA-Saclay, F-91191 Gif-sur-Yvette Cedex (France); Dolag, K. [University Observatory Munich, Scheinerstr. 1, D-81679 Munich (Germany); Markevitch, M. [Astrophysics Science Division, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

2013-11-10T23:59:59.000Z

80

Velocity distributions in clusters of galaxies  

E-Print Network [OSTI]

We employ a high-resolution dissipationless N-body simulation of a galaxy cluster to investigate the impact of subhalo selection on the resulting velocity distributions. Applying a lower limit on the present bound mass of subhalos leads to high subhalo velocity dispersions compared to the diffuse dark matter (positive velocity bias) and to a considerable deviation from a Gaussian velocity distribution (kurtosis -0.6). However, if subhalos are required to exceed a minimal mass before accretion onto the host, the velocity bias becomes negligible and the velocity distribution is close to Gaussian (kurtosis -0.15). Recently it has been shown that the latter criterion results in subhalo samples that agree well with the observed number-density profiles of galaxies in clusters. Therefore we argue that the velocity distributions of galaxies in clusters are essentially un-biased. The comparison of the galaxy velocity distribution and the sound speed, derived from scaling relations of X-ray observations, results in an average Mach number of 1.24. Altogether 65% of the galaxies move supersonically and 8% have Mach numbers larger than 2 with respect to the intra cluster gas.

A. Faltenbacher; J. Diemand

2006-02-08T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Logistics clusters : prevalence and impact  

E-Print Network [OSTI]

Governments around the world are investing significant resources in the development and expansion of logistics clusters. This dissertation analyzes the cluster phenomenon focusing on four topics. First, it develops a ...

Rivera Virgüez, Myriam Liliana

2014-01-01T23:59:59.000Z

82

Galactic Open Clusters  

E-Print Network [OSTI]

The study of open clusters has a classic feel to it since the subject predates anyone alive today. Despite the age of this topic, I show via an ADS search that its relevance and importance in astronomy has grown faster in the last few decades than astronomy in general. This is surely due to both technical reasons and the interconnection of the field of stellar evolution to many branches of astronomy. In this review, I outline what we know today about open clusters and what they have taught us about a range of topics from stellar evolution to Galactic structure to stellar disk dissipation timescales. I argue that the most important astrophysics we have learned from open clusters is stellar evolution and that its most important product has been reasonably precise stellar ages. I discuss where open cluster research is likely to go in the next few years, as well as in the era of 20m telescopes, SIM, and GAIA. Age will continue to be of wide relevance in astronomy, from cosmology to planet formation timescales, and with distance errors soon no longer a problem, improved ages will be critically important to many of the most fascinating astrophysical questions.

Ted von Hippel

2005-09-06T23:59:59.000Z

83

Connecting Remote Clusters with ATM  

SciTech Connect (OSTI)

Sandia's entry into utilizing clusters of networked workstations is called Computational Plant or CPlant for short. The design of CPlant uses Ethernet to boot the individual nodes, Myrinet to communicate within a node cluster, and ATM to connect between remote clusters. This SAND document covers the work done to enable the use of ATM on the CPlant nodes in the Fall of 1997.

Hu, T.C.; Wyckoff, P.S.

1998-10-01T23:59:59.000Z

84

Derivatized gold clusters and antibody-gold cluster conjugates  

DOE Patents [OSTI]

Antibody- or antibody fragment-gold cluster conjugates are shown wherein the conjugate size can be as small as 5.0 nm. Methods and reagents are disclosed in which antibodies, Fab' or F(ab').sub.2 fragments thereof are covalently bound to a stable cluster of gold atoms. The gold clusters may contain 6, 8, 9, 11, 13, 55 or 67 gold atoms in their inner core. The clusters may also contain radioactive gold. The antibody-cluster conjugates are useful in electron microscopy applications as well as in clinical applications that include imaging, diagnosis and therapy.

Hainfeld, James F. (Shoreham, NY); Furuya, Frederic R. (Williston Park, NY)

1994-11-01T23:59:59.000Z

85

Spectral Energy Distributions and Age Estimates of 78 Star Clusters in M33  

E-Print Network [OSTI]

In this third paper of our series, we present CCD spectrophotometry of 78 star clusters that were detected by Chandar, Bianchi, & Ford in the nearby spiral galaxy M33. CCD images of M33 were obtained as a part of the BATC Color Survey of the sky in 13 intermediate-band filters from 3800 to 10000{\\AA}. By aperture photometry, we obtain the spectral energy distributions of these 78 star clusters. As Chandar, Bianchi, & Ford did, we estimate the ages of our sample clusters by comparing the photometry of each object with theoretical stellar population synthesis models for different values of metallicity. We find that the sample clusters formed continuously in M33 from $\\sim 3\\times10^6$ -- $10^{10}$ years. This conclusion is consistent with Chandar, Bianchi, & Ford. The results also show that, there are two peaks in cluster formation, at $\\sim 8\\times10^6$ and $\\sim 10^9$ years in these clusters.

Ma, J; Chen, J; Wu, H; Jiang, Z; Xue, S; Zhu, J; Ma, Jun; Zhou, Xu; Chen, Jiansheng; Wu, Hong; Jiang, Zhaoji; Xue, Suijian; Zhu, Jin

2002-01-01T23:59:59.000Z

86

Raman scattering from sp2 carbon clusters  

Science Journals Connector (OSTI)

Raman spectra of B ion-implanted glassy carbon (GC) and hydrogenated amorphous carbon (a-C:H) films have been measured as a function of polarization direction of the scattered light and excitation wavelength. Raman bands of GC implanted heavily with a fluence of more than 5×1015 B ions/cm2 and a-C:H films show a frequency-independent depolarization ratio, suggesting the existence of sp2 carbon clusters in these samples. It was found that Raman spectra of GC implanted heavily with a fluence of more than 5×1015 B ions/cm2 varied with the excitation wavelength. From a comparative study of the heavily implanted GC and a-C:H films, the variation of the Raman spectra with the excitation wavelength observed for the heavily implanted GC is interpreted in terms of ?-?* resonant Raman scattering from sp2 carbon clusters having various sizes.

M. Yoshikawa; N. Nagai; M. Matsuki; H. Fukuda; G. Katagiri; H. Ishida; A. Ishitani; I. Nagai

1992-09-15T23:59:59.000Z

87

The Era of Star Formation in Galaxy Clusters  

E-Print Network [OSTI]

We analyze the star formation properties of 16 infrared-selected, spectroscopically confirmed galaxy clusters at $1 1.35$. Using infrared luminosities measured with deep Spitzer/MIPS observations at 24 $\\mu$m, along with robust optical+IRAC photometric redshifts and SED-fitted stellar masses, we present the dust-obscured star-forming fractions, star formation rates and specific star formation rates in these clusters as functions of redshift and projected clustercentric radius. We find that $z\\sim 1.4$ represents a transition redshift for the ISCS sample, with clear evidence of an unquenched era of cluster star formation at earlier times. Beyond this redshift the fraction of star-forming cluster members increases monotonically toward the cluster centers. Indeed, the specific star formation rate in the cores of these distant clusters is consistent with field values at similar redshifts, indicating that at $z>1.4$ environment-dependent quenching had not yet been established in ISCS clusters. Combining these obse...

Brodwin, M; Gonzalez, Anthony H; Zeimann, G R; Snyder, G F; Mancone, C L; Pope, A; Eisenhardt, P R; Stern, D; Alberts, S; Ashby, M L N; Brown, M J I; Chary, R -R; Dey, Arjun; Galametz, A; Gettings, D P; Jannuzi, B T; Miller, E D; Moustakas, J; Moustakas, L A

2013-01-01T23:59:59.000Z

88

White Dwarfs in Globular Clusters  

E-Print Network [OSTI]

We review empirical and theoretical findings concerning white dwarfs in Galactic globular clusters. Since their detection is a critical issue we describe in detail the various efforts to find white dwarfs in globular clusters. We then outline the advantages of using cluster white dwarfs to investigate the formation and evolution of white dwarfs and concentrate on evolutionary channels that appear to be unique to globular clusters. We also discuss the usefulness of globular cluster white dwarfs to provide independent information on the distances and ages of globular clusters, information that is very important far beyond the immediate field of white dwarf research. Finally, we mention possible future avenues concerning globular cluster white dwarfs, like the study of strange quark matter or plasma neutrinos.

S. Moehler; G. Bono

2011-06-30T23:59:59.000Z

89

ON THE CLUSTERING OF SUBMILLIMETER GALAXIES  

SciTech Connect (OSTI)

We measure the angular two-point correlation function of submillimeter galaxies (SMGs) from 1.1 mm imaging of the COSMOS field with the AzTEC camera and ASTE 10 m telescope. These data yield one of the largest contiguous samples of SMGs to date, covering an area of 0.72 deg{sup 2} down to a 1.26 mJy beam{sup -1} (1{sigma}) limit, including 189 (328) sources with S/N {>=}3.5 (3). We can only set upper limits to the correlation length r{sub 0}, modeling the correlation function as a power law with pre-assigned slope. Assuming existing redshift distributions, we derive 68.3% confidence level upper limits of r{sub 0} {approx}< 6-8h{sup -1} Mpc at 3.7 mJy and r{sub 0} {approx}< 11-12 h{sup -1} Mpc at 4.2 mJy. Although consistent with most previous estimates, these upper limits imply that the real r{sub 0} is likely smaller. This casts doubts on the robustness of claims that SMGs are characterized by significantly stronger spatial clustering (and thus larger mass) than differently selected galaxies at high redshift. Using Monte Carlo simulations we show that even strongly clustered distributions of galaxies can appear unclustered when sampled with limited sensitivity and coarse angular resolution common to current submillimeter surveys. The simulations, however, also show that unclustered distributions can appear strongly clustered under these circumstances. From the simulations, we predict that at our survey depth, a mapped area of 2 deg{sup 2} is needed to reconstruct the correlation function, assuming smaller beam sizes of future surveys (e.g., the Large Millimeter Telescope's 6'' beam size). At present, robust measures of the clustering strength of bright SMGs appear to be below the reach of most observations.

Williams, Christina C.; Giavalisco, Mauro; Yun, Min S.; Pope, Alexandra; Wilson, Grant W.; Cybulski, Ryan; Schloerb, F. Peter [Astronomy Department, University of Massachusetts, 710 North Pleasant Street, Amherst, MA 01003 (United States); Porciani, Cristiano [Argelander-Institut fuer Astronomie der Universitaet Bonn, Auf dem Huegel 71, D-53121 Bonn (Germany); Scott, Kimberly S. [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Austermann, Jason E. [Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, CO 80309 (United States); Aretxaga, Itziar; Hughes, David H. [Instituto Nacional de Astrofisica, Optica y Electronica (INAOE), Aptdo. Postal 51 y 216, 72000 Puebla, Pue. (Mexico); Hatsukade, Bunyo; Kawabe, Ryo [Nobeyama Radio Observatory, Minamimaki, Minamisaku, Nagano 384-1805 (Japan); Lee, Kyoung-Soo [Yale Center for Astronomy and Astrophysics, Department of Physics, Yale University, New Haven, CT 06520 (United States); Kohno, Kotaro [Institute of Astronomy, the University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan); Perera, Thushara, E-mail: ccwillia@astro.umass.edu [Department of Physics, Illinois Wesleyan University, Bloomington, IL 61701 (United States)

2011-06-01T23:59:59.000Z

90

CLUSTER LENSING PROFILES DERIVED FROM A REDSHIFT ENHANCEMENT OF MAGNIFIED BOSS-SURVEY GALAXIES  

SciTech Connect (OSTI)

We report the first detection of a redshift-depth enhancement of background galaxies magnified by foreground clusters. Using 300,000 BOSS survey galaxies with accurate spectroscopic redshifts, we measure their mean redshift depth behind four large samples of optically selected clusters from the Sloan Digital Sky Survey (SDSS) surveys, totaling 5000-15,000 clusters. A clear trend of increasing mean redshift toward the cluster centers is found, averaged over each of the four cluster samples. In addition, we find similar but noisier behavior for an independent X-ray sample of 158 clusters lying in the foreground of the current BOSS sky area. By adopting the mass-richness relationships appropriate for each survey, we compare our results with theoretical predictions for each of the four SDSS cluster catalogs. The radial form of this redshift enhancement is well fitted by a richness-to-mass weighted composite Navarro-Frenk-White profile with an effective mass ranging between M{sub 200} {approx} 1.4-1.8 Multiplication-Sign 10{sup 14} M{sub Sun} for the optically detected cluster samples, and M{sub 200} {approx} 5.0 Multiplication-Sign 10{sup 14} M{sub Sun} for the X-ray sample. This lensing detection helps to establish the credibility of these SDSS cluster surveys, and provides a normalization for their respective mass-richness relations. In the context of the upcoming bigBOSS, Subaru Prime Focus Spectrograph, and EUCLID-NISP spectroscopic surveys, this method represents an independent means of deriving the masses of cluster samples for examining the cosmological evolution, and provides a relatively clean consistency check of weak-lensing measurements, free from the systematic limitations of shear calibration.

Coupon, Jean; Umetsu, Keiichi [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China); Broadhurst, Tom, E-mail: coupon@asiaa.sinica.edu.tw [Department of Theoretical Physics, University of Basque Country UPV/EHU, P.O. Box 644, E-48080 Bilbao (Spain)

2013-07-20T23:59:59.000Z

91

LoCuSS: Connecting the Dominance and Shape of Brightest Cluster Galaxies with the Assembly History of Massive Clusters  

E-Print Network [OSTI]

We study the luminosity gap, dm12, between the first and second ranked galaxies in a sample of 59 massive galaxy clusters, using data from the Hale Telescope, HST, Chandra, and Spitzer. We find that the dm12 distribution, p(dm12), is a declining function of dm12, to which we fitted a straight line: p(dm12) propto -(0.13+/-0.02)dm12. The fraction of clusters with "large" luminosity gaps is p(dm12>=1)=0.37+/-0.08, which represents a 3sigma excess over that obtained from Monte Carlo simulations of a Schechter function that matches the mean cluster galaxy luminosity function. We also identify four clusters with "extreme" luminosity gaps, dm12>=2, giving a fraction of p(dm12>=2)=0.07+0.05-0.03. More generally, large luminosity gap clusters are relatively homogeneous, with elliptical/disky brightest cluster galaxies (BCGs), cuspy gas density profiles (i.e. strong cool cores), high concentrations, and low substructure fractions. In contrast, small luminosity gap clusters are heterogeneous, spanning the full range of...

Smith, Graham P; Dariush, A; Sanderson, A J R; Ponman, T J; Stott, J P; Haines, C P; Egami, E; Stark, D P

2010-01-01T23:59:59.000Z

92

FT-ICR Study of Precursor Clusters of Single Wall Carbon Nanotubes (SWNTs)  

E-Print Network [OSTI]

gas was injected to the nozzle. In the atmosphere of helium gas, vaporized atoms condensed to clusters vaporization of Ni/Co and Ni/Y doped graphite samples used for the macroscopic laser-oven production of SWNTs was drastically different. The chemical reaction of these clusters with NO gas was used as the probe

Maruyama, Shigeo

93

iVIBRATE: Interactive Visualization Based Framework for Clustering Large Datasets  

E-Print Network [OSTI]

iVIBRATE: Interactive Visualization Based Framework for Clustering Large Datasets Keke Chen Ling of large datasets continues to be one of the most important problems in large- scale data analysis. A commonly used methodology for cluster analysis on large datasets is the three-phase framework of "sampling

94

EVOLUTION OF SHOCKS AND TURBULENCE IN MAJOR CLUSTER MERGERS  

SciTech Connect (OSTI)

We performed a set of cosmological simulations of major mergers in galaxy clusters, in order to study the evolution of merger shocks and the subsequent injection of turbulence in the post-shock region and in the intra-cluster medium (ICM). The computations have been performed with the grid-based, adaptive mesh refinement hydrodynamical code Enzo, using a refinement criterion especially designed for refining turbulent flows in the vicinity of shocks. When a major merger event occurs, a substantial amount of turbulence energy is injected in the ICM of the newly formed cluster. Our simulations show that the shock launched after a major merger develops an ellipsoidal shape and gets broken by the interaction with the filamentary cosmic web around the merging cluster. The size of the post-shock region along the direction of shock propagation is of the order of 300 kpc h{sup -1}, and the turbulent velocity dispersion in this region is larger than 100 km s{sup -1}. We performed a scaling analysis of the turbulence energy within our cluster sample. The best fit for the scaling of the turbulence energy with the cluster mass is consistent with M{sup 5/3}, which is also the scaling law for the thermal energy in the self-similar cluster model. This clearly indicates the close relation between virialization and injection of turbulence in the cluster evolution. As for the turbulence in the cluster core, we found that within 2 Gyr after the major merger (the timescale for the shock propagation in the ICM), the ratio of the turbulent to total pressure is larger than 10%, and after about 4 Gyr it is still larger than 5%, a typical value for nearly relaxed clusters. Turbulence at the cluster center is thus sustained for several gigayears, which is substantially longer than typically assumed in the turbulent re-acceleration models, invoked to explain the statistics of observed radio halos. Striking similarities in the morphology and other physical parameters between our simulations and the 'symmetrical radio relics' found at the periphery of the merging cluster A3376 are finally discussed. In particular, the interaction between the merger shock and the filaments surrounding the cluster could explain the presence of 'notch-like' features at the edges of the double relics.

Paul, S.; Mannheim, K. [Institut fuer Theoretische Physik und Astrophysik, Universitaet Wuerzburg, Am Hubland, D-97074 Wuerzburg (Germany); Iapichino, L. [Zentrum fuer Astronomie der Universitaet Heidelberg, Institut fuer Theoretische Astrophysik, Albert-Ueberle-Strasse 2, D-69120 Heidelberg (Germany); Miniati, F. [Physics Department, Wolfgang-Pauli-Strasse 27, ETH-Zuerich, CH-8093 Zuerich (Switzerland); Bagchi, J. [Inter-University Center for Astronomy and Astrophysics, Pune University Campus, Pune 411 007 (India)

2011-01-01T23:59:59.000Z

95

Detecting Sunyaev–Zel'dovich clusters with Planck– III. Properties of the expected SZ cluster sample  

Science Journals Connector (OSTI)

......frequency of nu= 408 MHz, which has been adopted...parametrized with the plasma temperature and describes...conduction to the planet's atmosphere and the back-scattering on to the surface by the atmosphere. From the orbital elements...Recombination to Garching. Print Partners Ipskamp, Enschede......

Björn Malte Schäfer; Matthias Bartelmann

2007-05-01T23:59:59.000Z

96

Physical component analysis of galaxy cluster weak gravitational lensing data  

Science Journals Connector (OSTI)

......Optimization schemes for locating the best-fitting point...by weak-lensing data sets: we find the evidence...sample corresponds to a set of haloes that provide...a consequence of the domination of clusters by a single...methods: the natural basis set of elliptical NFW-profile......

Phil Marshall

2006-11-01T23:59:59.000Z

97

Globular Clusters in Dwarf Galaxies  

E-Print Network [OSTI]

Recent work on globular cluster systems in dwarf galaxies outside the Local Group is reviewed. Recent large imaging surveys with the Hubble Space Telescope and follow-up spectroscopy with 8-m class telescopes now allow us to compare the properties of massive star clusters in a wide range of galaxy types and environments. This body of work provides important constraints for theories of galaxy and star cluster formation and evolution.

Bryan W. Miller

2006-06-02T23:59:59.000Z

98

WMAP constraints on the Intra-Cluster Medium  

E-Print Network [OSTI]

We devise a Monte-Carlo based, optimized filter match method to extract the thermal Sunyaev-Zel'dovich (SZ) signature of a catalog of 116 low-redshift X-ray clusters from the first year data release of the Wilkinson Microwave Anisotropy Probe (WMAP). We detect an over-all amplitude for the SZ signal at the ~ 8-sigma level, yielding a combined constraint of f_{gas}h = 0.08 +/- 0.01 (ran) +/- 0.01 (sys) on the gas mass fraction of the Intra-Cluster Medium. We also compile X-ray estimated gas fractions from the literature for our sample, and find that they are consistent with the SZ estimates at the 2-sigma level, while both show an increasing trend with X-ray temperature. Nevertheless, our SZ estimated gas fraction is 30-40% smaller than the concordance LCDM cosmic average. We also express our observations in terms of the SZ flux-temperature relation, and compare it with other observations, as well as numerical studies. Based on its spectral and spatial signature, we can also extract the microwave point source signal of the clusters at the 3-sigma level, which puts the average microwave luminosity (at ~ 41 GHz) of bright cluster members (M_K 5 kev. Our work serves as an example for how correlation of SZ surveys with cluster surveys in other frequencies can significantly increase our physical understanding of the intra-cluster medium.

Niayesh Afshordi; Yen-Ting Lin; Alastair J. R. Sanderson

2004-08-30T23:59:59.000Z

99

Heating and cooling in the Perseus cluster core  

E-Print Network [OSTI]

It is well known that the radiative cooling time of the hot X-ray emitting gas in the cores of most clusters of galaxies is less than 10^10 yr. In many clusters the gas temperature also drops towards the centre. If we draw a causal connection between these two properties then we infer the presence of a cooling flow onto the central galaxy. High spectral resolution XMM-Newton data and high spatial resolution Chandra data, show however a lack of X-ray emitting gas below about one third of the cluster virial temperature. The explanation is that some form of heating balances cooling. The smoothness and similarity of the cooling time profiles and the flatness of the required heating profiles all indicate that we must seek a relatively gentle, quasi-continuous (on timescales heat source. The likely such source is the central black hole and its powerful jets which create bubble-like cavities in the inner hot gas. We briefly review the general heating and cooling statistics in an X-ray bright sample of cluster before we discuss the detailed situation in the Perseus cluster, the X-ray brightest cluster in the Sky.

A. C. Fabian; J. S. Sanders

2006-12-15T23:59:59.000Z

100

Winds from clu\\sters with non-uniform stellar distributions  

E-Print Network [OSTI]

We present analytic and numerical models of the `cluster wind' resulting from the multiple interactions of the winds ejected by the stars of a dense cluster of massive stars. We consider the case in which the distribution of stars (i.e., the number of stars per unit volume) within the cluster is spherically symmetric, has a power-law radial dependence, and drops discontinuously to zero at the outer radius of the cluster. We carry out comparisons between an analytic model (in which the stars are considered in terms of a spatially continuous injection of mass and energy) and 3D gasdynamic simulations (in which we include 100 stars with identical winds, located in 3D space by statistically sampling the stellar distribution function). From the analytic model, we find that for stellar distributions with steep enough radial dependencies the cluster wind flow develops a very high central density and a non-zero central velocity, and for steeper dependencies it becomes fully supersonic throughout the volume of the cluster (these properties are partially reproduced by the 3D numerical simulations). Therefore, the wind solutions obtained for stratified clusters can differ dramatically from the case of a homogeneous stellar distribution (which produces a cluster wind with zero central velocity, and a fully subsonic flow within the cluster radius). Finally, from our numerical simulations we compute predictions of X-ray emission maps and luminosities, which can be directly compared with observations of cluster wind flows.

Ary Rodríguez-González; J. Cantó; A. Esquivel; A. C. Raga; P. F. Velazquez

2007-08-09T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Substructure Analysis of Selected Low Richness 2dFGRS Clusters of Galaxies  

E-Print Network [OSTI]

Complementary one-, two-, and three-dimensional tests for detecting the presence of substructure in clusters of galaxies are applied to recently obtained data from the 2dF Galaxy Redshift Survey. The sample of 25 clusters used in this study includes 16 clusters not previously investigated for substructure. Substructure is detected at or greater than the 99% CL level in at least one test for 21 of the 25 clusters studied here. From the results, it appears that low richness clusters commonly contain subclusters participating in mergers. About half of the clusters have two or more components within 0.5 h^{-1} Mpc of the cluster centroid, and at least three clusters (Abell 1139, Abell 1663, and Abell S333) exhibit velocity-position characteristics consistent with the presence of possible cluster rotation, shear, or infall dynamics. The geometry of certain features is consistent with influence by the host supercluster environments. In general, our results support the hypothesis that low richness clusters relax to structureless equilibrium states on very long dynamical time scales (if at all).

William S. Burgett; Michael M. Vick; David S. Davis; Matthew Colless; Roberto De Propris; Ivan Baldry; Carlton Baugh; Joss Bland-Hawthorn; Terry Bridges; Russell Cannon; Shaun Cole; Chris Collins; Warrick Couch; Nicholas Cross; Gavin Dalton; Simon Driver; George Efstathiou; Richard Ellis; Carlos Frenk; Karl Glazebrook; Edward Hawkins; Carole Jackson; Ofer Lahav; Ian Lewis; Stuart Lumsden; Steve Maddox; Darren Madgwick; Peder Norberg; John A. Peacock; Will Percival; Bruce Peterson; Will Sutherland; Keith Taylor

2004-05-03T23:59:59.000Z

102

Antibody-gold cluster conjugates  

DOE Patents [OSTI]

Antibody- or antibody fragment-gold cluster conjugates are shown wherein the conjugate size can be about 5.0 nm. Methods and reagents are disclosed in which antibodies or Fab' fragments thereof are covalently bound to a stable cluster of gold atoms. 2 figs.

Hainfeld, J.F.

1988-06-28T23:59:59.000Z

103

Clustering of floaters by waves  

E-Print Network [OSTI]

We study experimentally how waves affect distribution of particles that float on a water surface. We show that clustering of small particles in a standing wave is a nonlinear effect with the clustering time decreasing as the square of the wave amplitude. In a set of random waves, we show that small floaters concentrate on a multi-fractal set.

P. Denissenko; G. Falkovich; S. Lukaschuk

2005-11-22T23:59:59.000Z

104

Architectural support for enhancing security in clusters  

E-Print Network [OSTI]

to security, numerous security loopholes in cluster servers come to the forefront. Clusters usually rely on Żrewalls for their security, but the Żrewalls cannot prevent all security attacks; therefore, cluster systems should be designed to be robust...

Lee, Man Hee

2009-05-15T23:59:59.000Z

105

E-Print Network 3.0 - adaptive cluster sampling Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

and Information Sciences 68 Proceedings of the 2010 Conference on Empirical Methods in Natural Language Processing, pages 346355, MIT, Massachusetts, USA, 9-11 October 2010. c...

106

Completion Report for Well Cluster ER-6-1  

SciTech Connect (OSTI)

Well Cluster ER-6-1 was constructed for the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office in support of the Nevada Environmental Restoration Division at the Nevada Test Site, Nye County, Nevada. This work was initiated as part of the Groundwater Characterization Project, now known as the Underground Test Area Project. The well cluster is located in southeastern Yucca Flat. Detailed lithologic descriptions with stratigraphic assignments for Well Cluster ER-6-1 are included in this report. These are based on composite drill cuttings collected every 3 meters and conventional core samples taken below 639 meters, supplemented by geophysical log data. Detailed petrographic, chemical, and mineralogical studies of rock samples were conducted on 11 samples to resolve complex interrelationships between several of the Tertiary tuff units. Additionally, paleontological analyses by the U.S. Geological Survey confirmed the stratigraphic assignments below 539 meters within the Paleozoic sedimentary section. All three wells in the Well ER-6-1 cluster were drilled within the Quaternary and Tertiary alluvium section, the Tertiary volcanic section, and into the Paleozoic sedimentary section.

Bechtel Nevada

2004-10-01T23:59:59.000Z

107

The evolution of star clusters: The resolved-star approach  

E-Print Network [OSTI]

We present the first results of a new technique to detect, locate, and characterize young dissolving star clusters. Using HST/ACS archival images of the nearby galaxy IC2574, we performed stellar PSF photometry and selected the most massive stars as our first test sample. We used a group-finding algorithm on the selected massive stars to find cluster candidates. We then plot the color-magnitude diagrams for each group, and use stellar evolutionary models to estimate their age. So far, we found 79 groups with ages of up to about 100 Myr, displaying various sizes and densities.

Anne Pellerin; Martin J. Meyer; Jason Harris; Daniela Calzetti

2008-02-29T23:59:59.000Z

108

Relative Ages of Globular Clusters  

E-Print Network [OSTI]

Ages of extragalactic globular clusters can provide valuable insights into the formation and evolution of galaxies. In this contribution the photometric methods of age dating old globular cluster systems are summarised. The spectroscopic approach is reviewed with an emphasis of the right choice of age diagnostics. We present a new method of quantifying the relatively best age-sensitive spectroscopic index given the quality of a data set and a certain theoretical stellar synthesis model. The relatively best diagnostic plot is constructed from the set of Lick indices and used to age date globular clusters in several early-type galaxies which are part of a large spectroscopic survey of extragalactic globular cluster systems. We find that, independently of host galaxy, metal-poor ([Fe/H] 8 Gyr) and coeval. Metal-rich clusters show a wide range of ages from ~15 down to a few Gyr.

Thomas H. Puzia

2002-10-18T23:59:59.000Z

109

Atomically precise (catalytic) particles synthesized by a novel cluster deposition instrument  

SciTech Connect (OSTI)

We report a new high vacuum instrument which is dedicated to the preparation of well-defined clusters supported on model and technologically relevant supports for catalytic and materials investigations. The instrument is based on deposition of size selected metallic cluster ions that are produced by a high flux magnetron cluster source. The throughput of the apparatus is maximized by collecting and focusing ions utilizing a conical octupole ion guide and a linear ion guide. The size selection is achieved by a quadrupole mass filter. The new design of the sample holder provides for the preparation of multiple samples on supports of various sizes and shapes in one session. After cluster deposition onto the support of interest, samples will be taken out of the chamber for a variety of testing and characterization.

Yin, C.; Tyo, E. [Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States)] [Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); Kuchta, K. [Extrel CMS, LLC, 575 Epsilon Dr. Suite 2, Pittsburgh, Pennsylvania 15238-2838 (United States)] [Extrel CMS, LLC, 575 Epsilon Dr. Suite 2, Pittsburgh, Pennsylvania 15238-2838 (United States); Issendorff, B. von [Physikalisches Institut, Universität Freiburg, Stefan-Meier Str. 21, D-79104 Freiburg (Germany)] [Physikalisches Institut, Universität Freiburg, Stefan-Meier Str. 21, D-79104 Freiburg (Germany); Vajda, S., E-mail: vajda@anl.gov [Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); Nanoscience and Technology Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); Institute for Molecular Engineering, The University of Chicago, 5747 South Ellis Avenue, Chicago, Illinois 60637 (United States); Department of Chemical and Environmental Engineering, School of Engineering and Applied Science, Yale University, 9 Hillhouse Avenue, New Haven, Connecticut 06520 (United States)

2014-05-07T23:59:59.000Z

110

BAG: a graph theoretic sequence clustering algorithm  

Science Journals Connector (OSTI)

In this paper, we first discuss issues in clustering biological sequences with graph properties, which inspired the design of our sequence clustering algorithm BAG. BAG recursively utilises several graph properties: biconnectedness, articulation points, pquasi-completeness, and domain knowledge specific to biological sequence clustering. To reduce the fragmentation issue, we have developed a new metric called cluster utility to guide cluster splitting. Clusters are then merged back with less stringent constraints. Experiments with the entire COG database and other sequence databases show that BAG can cluster a large number of sequences accurately while keeping the number of fragmented clusters significantly low.

Sun Kim; Jason Lee

2006-01-01T23:59:59.000Z

111

The CNOC Cluster Survey: Omega, sigma_8, Phi(L,z) Results, and Prospects for Lambda Measurement  

E-Print Network [OSTI]

Rich galaxy clusters are powerful probes of both cosmological and galaxy evolution parameters. The CNOC cluster survey was primarily designed to distinguish between Omega=1 and Omega~0.2 cosmologies. Projected foreground and background galaxies provide a field sample of comparable size. The results strongly support a low-density universe. The luminous cluster galaxies are about 10-30% fainter, depending on color, than the comparable field galaxies, but otherwise they show a slow and nearly parallel evolution. On the average, there is no excess star formation when galaxies fall into clusters. These data provide the basis for a simple Lambda measurement using the survey's clusters and the field data. The errors in Omega_M, Lambda, sigma_8 and galaxy evolution parameters could be reduced to a few percent with a sample of a few hundred clusters spread over the 0

R. G. Carlberg; H. K. C. Yee; H. Lin; C. W. Shepherd; P. Gravel; E. Ellingson; S. L. Morris; D. Schade; J. E. Hesser; J. B. Hutchings; J. B. Oke; R. Abraham; M. Balogh; G. Wirth; F. D. A. Hartwick; C. J. Pritchet; T. Smecker-Hane

1997-04-07T23:59:59.000Z

112

Cluster scaling and its redshift evolution from XMM-Newton  

E-Print Network [OSTI]

We put together the results of XMM-Newton observations of a number of representative group and cluster samples at low and high redshifts. These results confirm the entropy ramp as an explanation of the observed scaling relations. We observe a mild evolution in the entropy of clusters. The observed degree of evolution is consistent with expectations of the shock heating at a fixed overdensity (500) with respect to the critical density in LCDM. The study of the evolution in the pressure scaling imposes strong requirements in the definition of the average temperature of the cluster. The scaling temperature should be consistent to better than the 10% level. Once such a consistency is achieved, no additional evolution in the pressure has been detected in addition to the prediction of the shock heating in the LCDM Universe.

A. Finoguenov; H. Boehringer; J. P. F. Osmond; T. J. Ponman; A. J. R. Sanderson; Y. -Y. Zhang; M. Zimer

2005-05-19T23:59:59.000Z

113

Weak-strong clustering transition in renewing compressible flows  

E-Print Network [OSTI]

We investigate the statistical properties of Lagrangian tracers transported by a time-correlated compressible renewing flow. We show that the preferential sampling of the phase space performed by tracers yields significant differences between the Lagrangian statistics and its Eulerian counterpart. In particular, the effective compressibility experienced by tracers has a non-trivial dependence on the time correlation of the flow. We examine the consequence of this phenomenon on the clustering of tracers, focusing on the transition from the weak- to the strong-clustering regime. We find that the critical compressibility at which the transition occurs is minimum when the time correlation of the flow is of the order of the typical eddy turnover time. Further, we demonstrate that the clustering properties in time-correlated compressible flows are non-universal and are strongly influenced by the spatio-temporal structure of the velocity field.

Ajinkya Dhanagare; Stefano Musacchio; Dario Vincenzi

2014-11-01T23:59:59.000Z

114

PHAT Stellar Cluster Survey. II. Andromeda Project Cluster Catalog  

E-Print Network [OSTI]

We construct a stellar cluster catalog for the Panchromatic Hubble Andromeda Treasury (PHAT) survey using image classifications collected from the Andromeda Project citizen science website. We identify 2,753 clusters and 2,270 background galaxies within ~0.5 deg$^2$ of PHAT imaging searched, or ~400 kpc$^2$ in deprojected area at the distance of the Andromeda galaxy (M31). These identifications result from 1.82 million classifications of ~20,000 individual images (totaling ~7 gigapixels) by tens of thousands of volunteers. We show that our crowd-sourced approach, which collects >80 classifications per image, provides a robust, repeatable method of cluster identification. The high spatial resolution Hubble Space Telescope images resolve individual stars in each cluster and are instrumental in the factor of ~6 increase in the number of clusters known within the survey footprint. We measure integrated photometry in six filter passbands, ranging from the near-UV to the near-IR. PHAT clusters span a range of ~8 ma...

Johnson, L Clifton; Dalcanton, Julianne J; Wallace, Matthew L; Simpson, Robert J; Lintott, Chris J; Kapadia, Amit; Skillman, Evan D; Caldwell, Nelson; Fouesneau, Morgan; Weisz, Daniel R; Williams, Benjamin F; Beerman, Lori C; Gouliermis, Dimitrios A; Sarajedini, Ata

2015-01-01T23:59:59.000Z

115

SPATIAL ANISOTROPY OF GALAXY KINEMATICS IN SLOAN DIGITAL SKY SURVEY GALAXY CLUSTERS  

SciTech Connect (OSTI)

Measurements of galaxy cluster kinematics are important in understanding the dynamical state and evolution of clusters of galaxies, as well as constraining cosmological models. While it is well established that clusters exhibit non-spherical geometries, evident in the distribution of galaxies on the sky, azimuthal variations of galaxy kinematics within clusters have yet to be observed. Here we measure the azimuthal dependence of the line-of-sight velocity dispersion profile in a stacked sample of 1743 galaxy clusters from the Sloan Digital Sky Survey (SDSS). The clusters are drawn from the SDSS DR8 redMaPPer catalog. We find that the line-of-sight velocity dispersion of galaxies lying along the major axis of the central galaxy is larger than those that lie along the minor axis. This is the first observational detection of anisotropic kinematics of galaxies in clusters. We show that the result is consistent with predictions from numerical simulations. Furthermore, we find that the degree of projected anisotropy is strongly dependent on the line-of-sight orientation of the galaxy cluster, opening new possibilities for assessing systematics in optical cluster finding.

Skielboe, Andreas; Wojtak, Radoslaw; Pedersen, Kristian [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen (Denmark); Rozo, Eduardo [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States); Rykoff, Eli S. [SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States)

2012-10-10T23:59:59.000Z

116

Adhesive Gravitational Clustering  

E-Print Network [OSTI]

The notion of `adhesion' has been advanced for the phenomenon of stabilization of large-scale structure emerging from gravitational instability of a cold medium. Recently, the physical origin of adhesion has been identified: a systematic derivation of the equations of motion for the density and the velocity fields leads naturally to the key equation of the `adhesion approximation' - however, under a set of strongly simplifying assumptions. In this work, we provide an evaluation of the current status of adhesive gravitational clustering and a clear explanation of the assumptions involved. Furthermore, we propose systematic generalizations with the aim to relax some of the simplifying assumptions. We start from the general Newtonian evolution equations for self-gravitating particles on an expanding Friedmann background and recover the popular `dust model' (pressureless fluid), which breaks down after the formation of density singularities; then we investigate, in a unified framework, two other models which, under the restrictions referred to above, lead to the `adhesion approximation'. We apply the Eulerian and Lagrangian perturbative expansions to these new models and, finally, we discuss some non-perturbative results that may serve as starting points for workable approximations of non-linear structure formation in the multi-stream regime. In particular, we propose a new approximation that includes, in limiting cases, the standard `adhesion model' and the Eulerian as well as Lagrangian first-order approximations.

Thomas Buchert; Alvaro Dominguez

2005-06-21T23:59:59.000Z

117

The spatial evaluation of neighborhood clusters of birth defects  

SciTech Connect (OSTI)

Spatial statistics have recently been applied in epidemiology to evaluate clusters of cancer and birth defects. Their use requires a comparison population, drawn from the population at risk for disease, that may not always be readily available. In this dissertation the plausibility of using data on all birth defects, available from birth defects registries, as a surrogate for the spatial distribution of all live births in the analysis of clusters is assessed. Three spatial statistics that have been applied in epidemiologic investigations of clusters, nearest neighbor distance, average interpoint distance, and average distance to a fixed point, were evaluated by computer simulation for their properties in a unit square, and in a zip code region. Comparison of spatial distributions of live births and birth defects was performed by drawing samples of live births and birth defects from Santa Clara County, determining the street address at birth, geocoding this address and evaluating the resultant maps using various statistical techniques. The proposed method was then demonstrated on a previously confirmed cluster of oral cleft cases. All live births for the neighborhood were geocoded, as were all birth defects. Evaluation of this cluster using the nearest neighbor and average interpoint distance statistics was performed using randomization techniques with both the live births population and the birth defect population as comparison groups. 113 refs., 36 figs., 16 tabs.

Frisch, J.D.

1990-04-16T23:59:59.000Z

118

Infrared spectroscopy of ionic clusters  

SciTech Connect (OSTI)

This thesis describes new experiments wherein the infrared vibrational predissociation spectra of a number of mass-selected ionic cluster systems have been obtained and analyzed in the 2600 to 4000 cm{sup {minus}1} region. The species studied include: the hydrated hydronium ions, H{sub 3}O{sup +} (H{sub 2}O){sub 3 {minus}10}, ammoniated ammonium ions, NH{sub 4}{sup +}(NH{sub 3}){sub 1 {minus}10} and cluster ions involving both water and ammonia around an ammonium ion core, (mixed clusters) NH{sub 4}{sup +}(NH{sub 3}){sub n}(H{sub 2}O){sub m} (n+m=4). In each case, the spectra reveal well resolved structures that can be assigned to transitions arising from the vibrational motions of both the ion core of the clusters and the surrounding neutral solvent molecules. 154 refs., 19 figs., 8 tabs.

Price, J.M. (California Univ., Berkeley, CA (USA). Dept. of Chemistry Lawrence Berkeley Lab., CA (USA))

1990-11-01T23:59:59.000Z

119

Magnetism in small vanadium clusters  

Science Journals Connector (OSTI)

Using the self-consistent-field molecular-orbital theory and the density-functional approximation, we show that vanadium could become magnetic if its size and dimension were constrained. This is illustrated for vanadium forming clusters with body-centered-cubic (bcc) geometry as well as for linear chains. The magnetic moment of the bcc clusters is found to vanish abruptly as the size increases, while the clusters always retain their moment in the linear-chain configurations. The moments are also found to be finite for large interatomic spacings irrespective of the cluster topology, and tend to vanish when the interatomic distances are reduced. The results are explained by using a simple Stoner criterion.

Feng Liu; S. N. Khanna; P. Jena

1991-04-01T23:59:59.000Z

120

X-RAY PROPERTIES OF PREMAIN-SEQUENCE STARS IN THE ORION NEBULA CLUSTER WITH KNOWN ROTATION PERIODS  

E-Print Network [OSTI]

X-RAY PROPERTIES OF PRE­MAIN-SEQUENCE STARS IN THE ORION NEBULA CLUSTER WITH KNOWN ROTATION PERIODS Nebula Cluster (ONC) to study the X-ray properties of a large sample of pre­main-sequence (PMS) stars with optically determined rotation periods. Our goal is to elucidate the origins of X-rays in PMS stars

Barsony, Mary

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Cluster Dynamics of Planetary Waves  

E-Print Network [OSTI]

The dynamics of nonlinear atmospheric planetary waves is determined by a small number of independent wave clusters consisting of a few connected resonant triads. We classified the different types of connections between neighboring triads that determine the general dynamics of a cluster. Each connection type corresponds to substantially different scenarios of energy flux among the modes. The general approach can be applied directly to various mesoscopic systems with 3-mode interactions, encountered in hydrodynamics, astronomy, plasma physics, chemistry, medicine, etc.

Elena Kartashova; Victor S. L'vov

2008-11-05T23:59:59.000Z

122

Incremental Cluster-Based Retrieval using Compressed Cluster-Skipping Inverted Files  

E-Print Network [OSTI]

Incremental Cluster-Based Retrieval using Compressed Cluster-Skipping Inverted Files ISMAIL SENGOR ________________________________________________________________________ We propose a unique cluster-based retrieval (CBR) strategy using a new cluster-skipping inverted file for improving query processing efficiency. The new inverted file incorporates cluster membership and centroid

Can, Fazli

123

Incremental Cluster-Based Retrieval Using Compressed Cluster-Skipping Inverted Files  

E-Print Network [OSTI]

15 Incremental Cluster-Based Retrieval Using Compressed Cluster-Skipping Inverted Files ISMAIL cluster-based retrieval (CBR) strategy using a new cluster-skipping inverted file for improving query processing efficiency. The new inverted file incorporates cluster member- ship and centroid information along

Ulusoy, Ă?zgĂĽr

124

uvbyCaHbeta CCD Photometry of Clusters. V. The Metal-Deficient Open Cluster NGC 2243  

E-Print Network [OSTI]

CCD photometry on the intermediate-band uvbyCaHbeta system is presented for the metal-deficient open cluster, NGC 2243. Restricting the data to probable single members of the cluster using the CMD and the photometric indices alone generates a sample of 100 stars at the cluster turnoff. The average E(b-y) = 0.039 (0.003 s.e.m.) or E(B-V) = 0.055 (0.004 s.e.m.), where the errors refer to internal errors alone. With this reddening, [Fe/H] is derived from both m_1 and hk, using b-y and Hbeta as the temperature index. The agreement among the four approaches is excellent, leading to a final weighted average of [Fe/H] = -0.57 (0.03 s.e.m.) for the cluster, on a scale where the Hyades has [Fe/H] = +0.12. Using a combination of photometric and spectroscopic data, 27 probable cluster members are identified and used to delineate the red giant branch and a well-defined clump at V = 13.70, while eliminating the so-called second clump at V = 14.1. Interpolation between isochrones of appropriate [Fe/H] leads to an apparent ...

Anthony-Twarog, B J; Twarog, B A

2004-01-01T23:59:59.000Z

125

vbyCaHbeta CCD Photometry of Clusters. VI. The Metal-Deficient Open Cluster NGC 2420  

E-Print Network [OSTI]

CCD photometry on the intermediate-band vbyCaHbeta system is presented for the metal-deficient open cluster, NGC 2420. Restricting the data to probable single members of the cluster using the CMD and the photometric indices alone generates a sample of 106 stars at the cluster turnoff. The average E(b-y) = 0.03 +/- 0.003 (s.e.m.) or E(B-V) = 0.050 +/- 0.004 (s.e.m.), where the errors refer to internal errors alone. With this reddening, [Fe/H] is derived from both m1 and hk, using b-y and Hbeta as the temperature index. The agreement among the four approaches is reasonable, leading to a final weighted average of [Fe/H] = -0.37 +/- 0.05 (s.e.m.) for the cluster, on a scale where the Hyades has [Fe/H] = +0.12. When combined with the abundances from DDO photometry and from recalibrated low-resolution spectroscopy, the mean metallicity becomes [Fe/H] = -0.32 +/- 0.03. It is also demonstrated that the average cluster abundances based upon either DDO data or low-resolution spectroscopy are consistently reliable to 0....

Anthony-Twarog, B J; Cracraft, M; Twarog, B A; Anthony-Twarog, Barbara J.; Tanner, Delora; Cracraft, Misty; Twarog, Bruce A.

2005-01-01T23:59:59.000Z

126

uvbyCaHbeta CCD Photometry of Clusters. III. The Most Metal-Rich Open Cluster, NGC 6253  

E-Print Network [OSTI]

CCD photometry on the intermediate-band uvbyCaH-beta system is presented for the old open cluster, NGC 6253. Despite a high level of field star contamination due to its location toward the galactic center, combination of the data from the multiple color indices with the core cluster sample derived from radial star counts leads to the identification of a set of highly probable, single cluster members. Photometric analysis of a select sample of 71 turnoff stars produces a reddening value of E(b-y) = 0.190 +/-0.002 (s.e.m.) or E(B-V) = 0.260 +/- 0.003 (s.e.m.) from 71 stars. The metallicity indices, delta-m1 and delta-hk, both identify this cluster as the most metal-rich object studied on either system to date. Simple extrapolation of the available metallicity calibrations leads to [Fe/H] ranging from +0.7 to +0.9. Metal-rich isochrones with overshoot imply an age between 2.5 and 3.5 Gyr, with an apparent distance modulus between (m-M)= 11.6 and 12.2, depending upon the isochrones used. The improvement in the fi...

Twarog, B A; De Lee, N

2003-01-01T23:59:59.000Z

127

CN ANOMALIES IN THE HALO SYSTEM AND THE ORIGIN OF GLOBULAR CLUSTERS IN THE MILKY WAY  

SciTech Connect (OSTI)

We explore the kinematics and orbital properties of a sample of red giants in the halo system of the Milky Way that are thought to have formed in globular clusters based on their anomalously strong UV/blue CN bands. The orbital parameters of the CN-strong halo stars are compared to those of the inner- and outer-halo populations as described by Carollo et al., and to the orbital parameters of globular clusters with well-studied Galactic orbits. The CN-strong field stars and the globular clusters both exhibit kinematics and orbital properties similar to the inner-halo population, indicating that stripped or destroyed globular clusters could be a significant source of inner-halo field stars, and suggesting that both the CN-strong stars and the majority of globular clusters are primarily associated with this population.

Carollo, Daniela [Department of Physics and Astronomy-Astronomy, Astrophysics and Astrophotonic Research Center Macquarie University-North Ryde, 2109 NSW (Australia); Martell, Sarah L. [Australian Astronomical Observatory, North Ryde, 2109 NSW (Australia); Beers, Timothy C. [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Freeman, Ken C., E-mail: daniela.carollo@mq.edu.au, E-mail: smartell@aao.gov.au, E-mail: beers@noao.edu, E-mail: kcf@mso.anu.edu.au [Research School of Astronomy and Astrophysics, Australian National University and Mount Stromlo Observatory, Cotter Road, Weston, ACT 2611 (Australia)

2013-06-01T23:59:59.000Z

128

A neural network clustering algorithm for the ATLAS silicon pixel detector  

E-Print Network [OSTI]

A novel technique to identify and split clusters created by multiple charged particles in the ATLAS pixel detector using a set of artificial neural networks is presented. Such merged clusters are a common feature of tracks originating from highly energetic objects, such as jets. Neural networks are trained using Monte Carlo samples produced with a detailed detector simulation. This technique replaces the former clustering approach based on a connected component analysis and charge interpolation. The performance of the neural network splitting technique is quantified using data from proton--proton collisions at the LHC collected by the ATLAS detector in 2011 and from Monte Carlo simulations. This technique reduces the number of clusters shared between tracks in highly energetic jets by up to a factor of three. It also provides more precise position and error estimates of the clusters in both the transverse and longitudinal impact parameter resolution.

ATLAS collaboration

2014-06-30T23:59:59.000Z

129

The Two-Point Correlation Function of Rich Clusters of Galaxies: Results from an Extended APM Cluster Redshift Survey  

E-Print Network [OSTI]

We present new estimates of the spatial two-point correlation function of rich clusters of galaxies selected from the APM Galaxy Survey. We have measured redshifts for a sample of $364$ clusters out to a depth of $\\sim 450\\hmpc$. The clusters have a mean space density of $\\bar{n} = 3.4\\times 10^{-5}\\hmpccc$. The two-point correlation function, $\\xi_{cc}$, for this sample is equal to unity at a pair-separation of $r_0 = 14.3\\pm1.75\\hmpc$ (2$\\sigma$ errors), consistent with our earlier results from a smaller sample. The new observations provide an accurate determination of the shape of $\\xi_{cc}$ to pair-separations of about $50\\hmpc$. Our results show that $\\xi_{cc}$ has a higher amplitude than expected according to the standard $\\Omega=1$ cold dark matter (CDM) model on spatial scales $2\\simlt s \\simlt 50\\hmpc$, but are in good agreement with scale-invariant fluctuations in either a low density CDM model or a critical density universe made up of a mixture of hot and cold dark matter. Our results provide strong constraints on so called `co-operative' models of galaxy formation in which the galaxy formation process introduces large-scale structure in the galaxy distribution.

G. B. Dalton; R. A. C. Croft; G. Efstathiou; W. J. Sutherland; S. J. Maddox; M. Davis

1994-07-25T23:59:59.000Z

130

Quantum Monte Carlo methods and lithium cluster properties  

SciTech Connect (OSTI)

Properties of small lithium clusters with sizes ranging from n = 1 to 5 atoms were investigated using quantum Monte Carlo (QMC) methods. Cluster geometries were found from complete active space self consistent field (CASSCF) calculations. A detailed development of the QMC method leading to the variational QMC (V-QMC) and diffusion QMC (D-QMC) methods is shown. The many-body aspect of electron correlation is introduced into the QMC importance sampling electron-electron correlation functions by using density dependent parameters, and are shown to increase the amount of correlation energy obtained in V-QMC calculations. A detailed analysis of D-QMC time-step bias is made and is found to be at least linear with respect to the time-step. The D-QMC calculations determined the lithium cluster ionization potentials to be 0.1982(14) [0.1981], 0.1895(9) [0.1874(4)], 0.1530(34) [0.1599(73)], 0.1664(37) [0.1724(110)], 0.1613(43) [0.1675(110)] Hartrees for lithium clusters n = 1 through 5, respectively; in good agreement with experimental results shown in the brackets. Also, the binding energies per atom was computed to be 0.0177(8) [0.0203(12)], 0.0188(10) [0.0220(21)], 0.0247(8) [0.0310(12)], 0.0253(8) [0.0351(8)] Hartrees for lithium clusters n = 2 through 5, respectively. The lithium cluster one-electron density is shown to have charge concentrations corresponding to nonnuclear attractors. The overall shape of the electronic charge density also bears a remarkable similarity with the anisotropic harmonic oscillator model shape for the given number of valence electrons.

Owen, R.K.

1990-12-01T23:59:59.000Z

131

Big Fish in Small Ponds: Massive Stars in the Low Mass Clusters of M83  

E-Print Network [OSTI]

We have used multi-wavelength Hubble Space Telescope WFC3 data of the starbursting spiral galaxy M83 in order to measure variations in the upper end of the stellar initial mass function (uIMF) using the production rate of ionizing photons in unresolved clusters with ages $\\leq$ 8 Myr. As in earlier papers on M51 and NGC 4214, the upper end of the stellar IMF in M83 is consistent with an universal IMF, and stochastic sampling of the stellar populations in the $\\lessapprox$ 10$^{3}$ Msun clusters are responsible for any deviations in this universality. The ensemble cluster population, as well as individual clusters, also imply that the most massive star in a cluster does not depend on the cluster mass. In fact, we have found that these small clusters seem to have an over-abundance of ionizing photons when compared to an expected universal or truncated IMF. This also suggests that the presence of massive stars in these clusters does not affect the star formation in a destructive way.

Andrews, J E; Chandar, R; Elmegreen, B G; Kennicutt, R C; Kim, Hwihyun; Krumholz, Mark R; Lee, J C; McElwee, Sean; O'Connell, R W; Whitmore, B

2014-01-01T23:59:59.000Z

132

Spontaneous emission of heavy clusters  

Science Journals Connector (OSTI)

The lifetimes of some heavy nuclei relative to the spontaneous emission of various clusters heavier than the alpha particle are estimated with a model extended from the fission theory of alpha decay, showing that this phenomenon is a new manifestation of the nuclear shell structure. A greater probability is obtained for parent-heavy-cluster combinations leading to a magic or almost magic daughter nucleus. The analytical formula obtained allows one to handle a large number of cases to search for new kinds of radioactivities.

D N Poenaru; M Ivascu; A Sandulescu; W Greiner

1984-01-01T23:59:59.000Z

133

The Herschel Virgo Cluster Survey – XVI. A cluster inventory  

Science Journals Connector (OSTI)

......University of Manchester, Oxford Road, Manchester M13 9PL, UK 5...using the same data reduction pipeline as the Virgo data, with the...have a mean value of zero (by design), the subtraction conserves...sigmav = 616s1, the cluster crossing time is of the order of 3-yr......

J. I. Davies; S. Bianchi; M. Baes; G. J. Bendo; M. Clemens; I. De Looze; S. di Serego Alighieri; J. Fritz; C. Fuller; C. Pappalardo; T. M. Hughes; S. Madden; M. W. L. Smith; J. Verstappen; C. Vlahakis

2014-01-01T23:59:59.000Z

134

sediment samples | EMSL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

sediment samples sediment samples Leads No leads are available at this time. Diffusional Motion of Redox Centers in Carbonate Electrolytes . Abstract: Ferrocene (Fc) and...

135

Water and Sediment Sampling  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

analytical laboratory limit below which any level present cannot be determined) Note: Sediment sample locations are co-located with off-site surface water sample locations. Surface...

136

Environmental Business Cluster EBC | Open Energy Information  

Open Energy Info (EERE)

Cluster EBC Cluster EBC Jump to: navigation, search Name Environmental Business Cluster (EBC) Place San Jose, California Zip CA 95113 Product The Environmental Business Cluster is a not-for-profit incubator sponsored by major financial groups such as Citibank, and San Jose University. It has facilitated funding for 50 eco-related start-up businesses. References Environmental Business Cluster (EBC)[1] LinkedIn Connections CrunchBase Profile No CrunchBase profile. Create one now! This article is a stub. You can help OpenEI by expanding it. Environmental Business Cluster (EBC) is a company located in San Jose, California . References ↑ "Environmental Business Cluster (EBC)" Retrieved from "http://en.openei.org/w/index.php?title=Environmental_Business_Cluster_EBC&oldid=345024

137

Perspectives for logistics clusters development in Russia  

E-Print Network [OSTI]

This thesis is a normative work aimed at identifying locations in Russia with high, medium and unclear potentials for logistics cluster development. As a framework this work uses four different models of logistics clusters: ...

Tantsuyev, Andriy

2012-01-01T23:59:59.000Z

138

Carbon Fiber Cluster Strategy | ornl.gov  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Economic Development | Carbon Fiber Cluster Strategy SHARE Carbon Fiber Cluster Strategy ORNL has a 40-year history in R&D on fiber-reinforced composite materials, and has been...

139

Electronic-structure calculations of cobalt clusters  

Science Journals Connector (OSTI)

The electric structure and magnetic properties of small cobalt clusters (4?n?19) have been studied using the spin-polarized discrete variational method within the local-density-functional theory. The results show that the magnetic moment of the Co13 cluster converges to that of the bulk, the average moment of the cluster is in agreement with the experiment. The Co13 cluster with icosahedral symmetry has the highest magnetic moment among the 13-atom isomers. The atomic magnetic moments of cobalt clusters have been discussed, in particular, with reference to changing cluster size and interatomic distances. The cluster symmetry is an important factor for determining the magnetic moments of the clusters.

Zhi-qiang Li and Bing-lin Gu

1993-05-15T23:59:59.000Z

140

Studying Dark Energy with Galaxy Clusters  

Science Journals Connector (OSTI)

Large yield cluster surveys, having well understood the cluster redshift distribution ... calibration’ techniques. With ‘self–calibration’ future surveys (for example, the SPT survey) having tens of thousands of ...

S. Majumdar

2007-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Lecture outline Densitybased clustering (DBScan)  

E-Print Network [OSTI]

point if for distance Eps : ­ |NEps(p)={q | dist(p,q) points: Not a core or a border point #12;Core, border and noise points Eps Eps Eps #12;Core, Border and Noise points Original Points Point types: core, border and noise Eps = 10, MinPts = 4 #12;Clusters

Terzi, Evimaria

142

Star clusters as diaries of galaxies  

E-Print Network [OSTI]

Most if not all stars form in star clusters. Thus the distribution of star clusters preserves the information on the star formation history of a galaxy. Massive clusters form only during episodes of high star formation activity whereas periods of low star formation activity cannot produce them. We present here the method of Maschberger & Kroupa (2007) to derive the star formation history of a galaxy from its star-cluster content.

Th. Maschberger; P. Kroupa

2007-06-11T23:59:59.000Z

143

Flexi-Cluster: A Simulator for a Single Compute Cluster Flexi-Cluster is a flexible, discrete-event simulation model for a single compute cluster,  

E-Print Network [OSTI]

-event simulation model for a single compute cluster, such as might be deployed within a compute grid. The model

144

Spectral Clustering of Synchronous Spike Trains 1 Spectral Clustering of Synchronous  

E-Print Network [OSTI]

Spectral Clustering of Synchronous Spike Trains 1 Spectral Clustering of Synchronous Spike Trains, University of Florida #12;Spectral Clustering of Synchronous Spike Trains 2 Outline Introduction Distance between two spike trains Clustering algorithm Results António Paiva, Sudhir Rao, Il Park and José Príncipe

Paiva, AntĂłnio R. C.

145

First Results On Shear-Selected Clusters From the Deep Lens Survey: Optical Imaging, Spectroscopy, and X-ray Followup  

E-Print Network [OSTI]

We present the first sample of galaxy clusters selected on the basis of their weak gravitational lensing shear. The shear induced by a cluster is a function of its mass profile and its redshift relative to the background galaxies being sheared; in contrast to more traditional methods of selecting clusters, shear selection does not depend on the cluster's star formation history, baryon content, or dynamical state. Because mass is the property of clusters which provides constraints on cosmological parameters, the dependence on these other parameters could induce potentially important biases in traditionally-selected samples. Comparison of a shear-selected sample with optically and X-ray selected samples is therefore of great importance. Here we present the first step toward a new shear-selected sample: the selection of cluster candidates from the first 8.6 deg$^2$ of the 20 deg$^2$ Deep Lens Survey (DLS), and tabulation of their basic properties such as redshifts and optical and X-ray counterparts.

Wittman, D; Hughes, J P; Margoniner, V E; Tyson, J A; Cohen, J G; Norman, D

2006-01-01T23:59:59.000Z

146

First Results On Shear-Selected Clusters From the Deep Lens Survey: Optical Imaging, Spectroscopy, and X-ray Followup  

E-Print Network [OSTI]

We present the first sample of galaxy clusters selected on the basis of their weak gravitational lensing shear. The shear induced by a cluster is a function of its mass profile and its redshift relative to the background galaxies being sheared; in contrast to more traditional methods of selecting clusters, shear selection does not depend on the cluster's star formation history, baryon content, or dynamical state. Because mass is the property of clusters which provides constraints on cosmological parameters, the dependence on these other parameters could induce potentially important biases in traditionally-selected samples. Comparison of a shear-selected sample with optically and X-ray selected samples is therefore of great importance. Here we present the first step toward a new shear-selected sample: the selection of cluster candidates from the first 8.6 deg$^2$ of the 20 deg$^2$ Deep Lens Survey (DLS), and tabulation of their basic properties such as redshifts and optical and X-ray counterparts.

D. Wittman; I. P. Dell'Antonio; J. P. Hughes; V. E. Margoniner; J. A. Tyson; J. G. Cohen; D. Norman

2005-07-26T23:59:59.000Z

147

uvbyCa H beta CCD Photometry of Clusters. VII. The Intermediate-Age Anticenter Cluster Melotte 71  

E-Print Network [OSTI]

CCD photometry on the intermediate-band uvbyCa H beta system is presented for the anticenter, intermediate-age open cluster, Melotte 71. Restricting the data to probable single members of the cluster using the color-magnitude diagram and the photometric indices alone generates a sample of 48 F dwarfs on the unevolved main sequence. The average E(b-y) = 0.148 +/- 0.003 (s.e.m.) or E(B-V) = 0.202 +/- 0.004 (s.e.m.), where the errors refer to internal errors alone. With this reddening, [Fe/H] is derived from both m1 and hk, using H beta and b-y as the temperature index, with excellent agreement among the four approaches and a final weighted average of [Fe/H] = -0.17 +/- 0.02 (s.e.m.) for the cluster, on a scale where the Hyades has [Fe/H] = +0.12. When adjusted for the higher reddening estimate, the previous metallicity estimates from Washington photometry and from spectroscopy are now in agreement with the intermediate-band result. From comparisons to isochrones of appropriate metallicity, the cluster age and d...

Twarog, B A; Corder, S

2006-01-01T23:59:59.000Z

148

Rural Knowledge Clusters: Implications for Minnesota State  

E-Print Network [OSTI]

Rural Knowledge Clusters: Implications for Minnesota State Colleges and Universities Prepared for. The Institute does not itself take positions on issues of public policy. #12;Rural Knowledge Clusters 3 Rural Knowledge Clusters: Model of Rural Innovation 5 Approach and Research Design 8 Case Studies

Levinson, David M.

149

Incremental Hierarchical Clustering of Text Documents  

E-Print Network [OSTI]

in incremental clustering of text documents as a part of Topic Detection and Tracking initiative ([1], [19], [10Incremental Hierarchical Clustering of Text Documents by Nachiketa Sahoo Adviser: Jamie Callan May 5, 2006 Abstract Incremental hierarchical text document clustering algorithms are important

Gordon, Geoffrey J.

150

Small Clusters Hit the Big Time  

Science Journals Connector (OSTI)

...In the next section, we focus on small water clusters, for which splittings resulting...experiment. Dynamics-Tunneling in Small Water Clusters The application of far-infrared...tunneling spectroscopy (34) to small water clusters (35-37) has recently led to...

1996-02-16T23:59:59.000Z

151

ESPC IDIQ Contract Sample  

Broader source: Energy.gov [DOE]

Document displays a sample indefinite delivery, indefinite quantity (IDIQ) energy savings performance contract (ESPC).

152

September 2004 Water Sampling  

Office of Legacy Management (LM)

Sampling at the Sampling at the Shirley Basin South, Wyoming, Disposal Site September 2013 LMS/SBS/S00613 This page intentionally left blank U.S. Department of Energy DVP-June 2013, Shirley Basin South, Wyoming September 2013 RIN 13065426 Page i Contents Sampling Event Summary ...............................................................................................................1 Shirley Basin South, Wyoming, Disposal Site Sample Location Map ............................................3 Data Assessment Summary ..............................................................................................................5 Water Sampling Field Activities Verification Checklist .............................................................7

153

Cluster radioactivities from an island of cluster emitters  

SciTech Connect (OSTI)

We have recently developed a realistic model for studying cluster radioactivities from actinide nuclei. This model uses a cubic potential in the overlapping region connected by a Yukawa-plus-exponential potential in the post-scission region. In the present work we use this model to study {sup 4}He, {sup 12}C, {sup 16}O, and {sup 28}Si radioactivities in the region of nuclides with proton and neutron number in the range {ital Z}=56--64 and {ital N}=58--72, which has been recently identified by Poenaru {ital et} {ital al}. as a new island of such cluster emitters. It is found that charge equilibration is not needed in the study of these radioactivities and the half-lives obtained for these decays lie very close to those reported by Poenaru {ital et} {ital al}. using their analytical super asymmetric fission model.

Shanmugam, G.; Carmel Vigila Bai, G.M. [Department of Physics, Manonmaniam Sundaranar University, Tirunelveli 627 002 (India)] [Department of Physics, Manonmaniam Sundaranar University, Tirunelveli 627 002 (India); Kamalaharan, B. [Department of Physics, Presidency College, Madras 600 005 (India)] [Department of Physics, Presidency College, Madras 600 005 (India)

1995-05-01T23:59:59.000Z

154

Combining cosmological constraints from cluster counts and galaxy clustering  

E-Print Network [OSTI]

Present and future large scale surveys offer promising probes of cosmology. For example the Dark Energy Survey (DES) is forecast to detect ~300 millions galaxies and thousands clusters up to redshift ~1.3. I here show ongoing work to combine two probes of large scale structure : cluster number counts and galaxy 2-point function (in real or harmonic space). The halo model (coupled to a Halo Occupation Distribution) can be used to model the cross-covariance between these probes, and I introduce a diagrammatic method to compute easily the different terms involved. Furthermore, I compute the joint non-Gaussian likelihood, using the Gram-Charlier series. Then I show how to extend the methods of Bayesian hyperparameters to Poissonian distributions, in a first step to include them in this joint likelihood.

Lacasa, Fabien

2014-01-01T23:59:59.000Z

155

Effervescent heating: constraints from nearby cooling flow clusters observed with XMM-Newton  

E-Print Network [OSTI]

We have used deprojected radial density and temperature profiles of a sample of 16 nearby CF clusters observed with XMM-Newton to test whether the effervescent heating model can satisfactorily explain the dynamics of CF clusters. For each cluster we derived the required extra heating as a function of cluster-centric distance for various values of the unknown parameters $\\dot M$ (mass deposition rate) and $f_c$ (conduction efficiency). We fitted the extra heating curve using the AGN effervescent heating function and derived the AGN parameters $L$ (the time-averaged luminosity) and $r_0$ (the scale radius where the bubbles start rising in the ICM). While we do not find any solution with the effervescent heating model for only one object, we do show that AGN and conduction heating are not cooperating effectively for half of the objects in our sample. For most of the clusters we find that, when a comparison is possible, the derived AGN scale radius $r_0$ and the observed AGN jet extension have the same order of magnitude. The AGN luminosities required to balance radiative losses are substantially lowered if the fact that the AGN deposits energy within a finite volume is taken into account. For the Virgo cluster, we find that the AGN power derived from the effervescent heating model is in good agreement with the observed jet power.

Rocco Piffaretti; Jelle Kaastra

2006-02-16T23:59:59.000Z

156

The Herschel Virgo Cluster Survey. XVIII. Star-forming dwarfs in a cluster environment  

E-Print Network [OSTI]

To assess the effects of the cluster environment on the different components of the interstellar medium, we analyse the FIR-submm properties of a sample of star-forming dwarf (SFD) galaxies detected by the Herschel Virgo Cluster Survey (HeViCS). We determine dust masses and dust temperatures by fitting a modified black body (MBB) function to the spectral energy distributions (SEDs). Stellar and gas masses, star formation rates (SFRs), and metallicities are obtained from the analysis of a set of ancillary data. Dust is detected in 49 out of 140 optically identified dwarfs covered by the HeViCS field; considering only dwarfs brighter than $m_B$ = 18 mag, this gives a detection rate of 43%. After evaluating different emissivity indices, we find that the FIR-submm SEDs are best-fit by $\\beta$=1.5, with a median dust temperature $T_d$ = 22.4 K. Assuming $\\beta$=1.5, 67% of the 23 galaxies detected in all five Herschel bands show emission at 500 $\\mu$m in excess of the MBB model. The excess is inversely correlated ...

Grossi, M; Madden, S C; Hughes, T M; Auld, R; Baes, M; Bendo, G J; Bianchi, S; Bizzocchi, L; Boquien, M; Boselli, A; Clemens, M; Corbelli, E; Cortese, L; Davies, J; De Looze, I; Alighieri, S di Serego; Fritz, J; Pappalardo, C; Pierini, D; Rémy-Ruyer, A; Smith, M W L; Verstappen, J; Viaene, S; Vlahakis, C

2014-01-01T23:59:59.000Z

157

The structure of star clusters in the outer halo of M31  

E-Print Network [OSTI]

We present a structural analysis of halo star clusters in M31 based on deep Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) imaging. The clusters in our sample span a range in galactocentric projected distance from 13 to 100 kpc and thus reside in rather remote environments. Ten of the clusters are classical globulars, while four are from the Huxor et al. (2005, 2008) population of extended, old clusters. For most clusters, contamination by M31 halo stars is slight, and so the profiles can be mapped reliably to large radial distances from their centres. We find that the extended clusters are well fit by analytic King (1962) profiles with ~20 parsec core radii and ~100 parsec photometric tidal radii, or by Sersic profiles of index ~1 (i.e. approximately exponential). Most of the classical globulars also have large photometric tidal radii in the range 50-100 parsec, however the King profile is a less good fit in some cases, particularly at small radii. We find 60 of the classical globular cluster...

Tanvir, N R; Ferguson, A M N; Huxor, A; Read, J I; Lewis, G F; Irwin, M J; Chapman, S; Ibata, R; Wilkinson, M I; McConnachie, A W; Martin, N F; Davies, M B; Bridges, T J

2012-01-01T23:59:59.000Z

158

Arc Statistics in Clusters: Galaxy Contribution  

E-Print Network [OSTI]

The frequency with which background galaxies appear as long arcs as a result of gravitational lensing by foreground clusters of galaxies has recently been found to be a very sensitive probe of cosmological models by Bartelmann et al. (1998). They have found that such arcs would be expected far less frequently than observed (by an order of magnitude) in the currently favored model for the universe, with a large cosmological constant $\\Omega_\\Lambda \\sim 0.7$. Here we analyze whether including the effect of cluster galaxies on the likelihood of clusters to generate long-arc images of background galaxies can change the statistics. Taking into account a variety of constraints on the properties of cluster galaxies, we find that there are not enough sufficiently massive galaxies in a cluster for them to significantly enhance the cross section of clusters to generate long arcs. We find that cluster galaxies typically enhance the cross section by only $\\lesssim 15%$.

R. A. Flores; A. H. Maller; J. R. Primack

1999-09-23T23:59:59.000Z

159

Submillimetre sources in rich cluster fields - source counts, redshift estimates, and cooling flow limits  

E-Print Network [OSTI]

Recent submillimetre surveys have revealed a population of dusty, high redshift sources of great cosmological significance for understanding dust-enshrouded star formation in distant galaxies, and for determining the origin of the far-IR background. In this paper, we analyze nine rich cluster fields mapped at 850 and 450 microns with the SCUBA array on the James Clerk Maxwell telescope. Lensing models of the clusters are developed in order to derive accurate source counts for our sample. VLA maps of the same clusters are used to help constrain the redshift distribution of our SCUBA detections. Implications for high redshift galaxies and for the far-IR background are discussed. We also provide limits on distributed dust produced by cooling flows in these clusters.

Scott C. Chapman; Douglas Scott; Colin Borys; Gregory G. Fahlman

2000-09-05T23:59:59.000Z

160

Volatility clustering in land markets  

E-Print Network [OSTI]

analysis. Applying a Lagrange Multiplier (LM) test for AutoRegressive Conditional Heteroskedasticity (ARCH) effects in the Canadian land markets, we find that clustering in land price returns exists in Alberta, Ontario, Quebec, and British Columbia... by even higher volatility and vice versa. III. Data and Descriptive Statistics The monthly land price index for each individual province is obtained from Statistics Canada, covering all of the Canadian provinces (Alberta, Ontario, Quebec...

Bao, Helen X. H.; Huang, Hui; Huang, Yu-Lieh; Lin, Pin-te

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

The Kinematics and Dynamics of the Globular Clusters and the Planetary Nebulae of NGC 5128  

E-Print Network [OSTI]

A new kinematic and dynamic study of the halo of the giant elliptical galaxy, NGC 5128, is presented. From a spectroscopically confirmed sample of 340 globular clusters and 780 planetary nebulae, the rotation amplitude, rotation axis, velocity dispersion, and the total dynamical mass are determined for the halo of NGC 5128. The globular cluster kinematics were searched for both radial dependence and metallicity dependence by subdividing the globular cluster sample into 158 metal-rich ([Fe/H] > -1.0) and 178 metal-poor ([Fe/H] < -1.0) globular clusters. Our results show the kinematics of the metal-rich and metal-poor subpopulations are quite similar. The kinematics are compared to the planetary nebula population where differences are apparent in the outer regions of the halo. The total mass of NGC 5128 is found using the Tracer Mass estimator (Evans et al. 2003), to determine the mass supported by internal random motions, and the spherical component of the Jeans equation to determine the mass supported by rotation. We find a total mass of (1.0+/-0.2) x 10^(12) Msun from the planetary nebulae data out to a projected radius of 90 kpc and (1.3+/-0.5) x 10^(12) Msun from the globular clusters out to a projected radius of 50 kpc. Lastly, we present a new and homogeneous catalog of known globular clusters in NGC 5128. This catalog combines all previous definitive cluster identifications from radial velocity studies and HST imaging studies, as well as 80 new globular clusters from a study of M.A. Beasley et al. (2007, in preparation).

Kristin A. Woodley; William E. Harris; Michael A. Beasley; Eric W. Peng; Terry J. Bridges; Duncan A. Forbes; Gretchen L. H. Harris

2007-04-10T23:59:59.000Z

162

Gas Sampling Considerations  

Science Journals Connector (OSTI)

Gas sampling is carried out to measure the quality of a gas. Gas samples are sometimes acquired by in situ observation within the main gas body by using remote or visual observation for specific properties. A mor...

Alvin Lieberman

1992-01-01T23:59:59.000Z

163

September 2004 Water Sampling  

Office of Legacy Management (LM)

event. Sampling Protocol Wells USGS-4 and USGS-8 were sampled using dedicated bladder pumps. Data from these wells are qualified with an "F" flag in the database indicating the...

164

September 2004 Water Sampling  

Office of Legacy Management (LM)

Old and New Rifle, Old and New Rifle, Colorado, Processing Sites August 2013 LMS/RFN/RFO/S00613 This page intentionally left blank U.S. Department of Energy DVP-June 2013, Rifle, Colorado August 2013 RIN 13065380 Page i Contents Sampling Event Summary ...............................................................................................................1 Sample Location Map, New Rifle, Colorado, Processing Site ........................................................5 Sample Location Map, Old Rifle, Colorado, Processing Site ..........................................................6 Data Assessment Summary ..............................................................................................................7 Water Sampling Field Activities Verification Checklist .............................................................9

165

September 2004 Water Sampling  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

3 3 Groundwater and Surface Water Sampling at the Tuba City, Arizona, Disposal Site November 2013 LMS/TUB/S00813 This page intentionally left blank U.S. Department of Energy DVP-August 2013, Tuba City, Arizona November 2013 RIN 13085553 Page i Contents Sampling Event Summary ...............................................................................................................1 Tuba City, Arizona, Disposal Site, Sample Location Map ..............................................................7 Data Assessment Summary ..............................................................................................................9 Water Sampling Field Activities Verification Checklist ...........................................................11

166

September 2004 Water Sampling  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

and October 2013 and October 2013 Groundwater Sampling at the Bluewater, New Mexico, Disposal Site December 2013 LMS/BLU/S00813 This page intentionally left blank U.S. Department of Energy DVP-August and October 2013, Bluewater, New Mexico December 2013 RIN 13085537 and 13095651 Page i Contents Sampling Event Summary ...............................................................................................................1 Private Wells Sampled August 2013 and October 2013, Bluewater, NM, Disposal Site ................3 Data Assessment Summary ..............................................................................................................5 Water Sampling Field Activities Verification Checklist .............................................................7

167

September 2004 Water Sampling  

Office of Legacy Management (LM)

3 3 Groundwater and Surface Water Sampling at the Slick Rock East and West, Colorado, Processing Sites November 2013 LMS/SRE/SRW/S0913 This page intentionally left blank U.S. Department of Energy DVP-September 2013, Slick Rock, Colorado November 2013 RIN 13095593 Page i Contents Sampling Event Summary ...............................................................................................................1 Slick Rock East and West, Colorado, Processing Sites, Sample Location Map .............................5 Data Assessment Summary ..............................................................................................................7 Water Sampling Field Activities Verification Checklist .............................................................9

168

September 2004 Water Sampling  

Office of Legacy Management (LM)

Riverton, Wyoming, Riverton, Wyoming, Processing Site September 2013 LMS/RVT/S00613 This page intentionally left blank U.S. Department of Energy DVP-June 2013, Riverton, Wyoming September 2013 RIN 13065379 Page i Contents Sampling Event Summary ...............................................................................................................1 Riverton, Wyoming, Processing Site, Sample Location Map .........................................................5 Data Assessment Summary ..............................................................................................................7 Water Sampling Field Activities Verification Checklist .............................................................9 Laboratory Performance Assessment ........................................................................................11

169

Constraining white-dwarf kicks in globular clusters : III. Cluster Heating  

E-Print Network [OSTI]

Recent observations of white dwarfs in globular clusters indicate that these stars may get a velocity kick during their time as giants. This velocity kick could originate naturally if the mass loss while on the asymptotic giant branch is slightly asymmetric. The kicks may be large enough to dramatically change the radial distribution of young white dwarfs, giving them larger energies than other stars in the cluster. As these energetic white dwarfs travel through the cluster they can impart their excess energy on the other stars in the cluster. This new heat source for globular clusters is expected to be largest during the clusters' youth.

Jeremy S. Heyl

2009-03-31T23:59:59.000Z

170

CANDELS OBSERVATIONS OF THE STRUCTURAL PROPERTIES OF CLUSTER GALAXIES AT z = 1.62  

SciTech Connect (OSTI)

We discuss the structural and morphological properties of galaxies in a z = 1.62 proto-cluster using near-IR imaging data from Hubble Space Telescope Wide Field Camera 3 data of the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS). The cluster galaxies exhibit a clear color-morphology relation: galaxies with colors of quiescent stellar populations generally have morphologies consistent with spheroids, and galaxies with colors consistent with ongoing star formation have disk-like and irregular morphologies. The size distribution of the quiescent cluster galaxies shows a deficit of compact ({approx}< 1 kpc), massive galaxies compared to CANDELS field galaxies at z = 1.6. As a result, the cluster quiescent galaxies have larger average effective sizes compared to field galaxies at fixed mass at greater than 90% significance. Combined with data from the literature, the size evolution of quiescent cluster galaxies is relatively slow from z {approx_equal} 1.6 to the present, growing as (1 + z){sup -0.6{+-}0.1}. If this result is generalizable, then it implies that physical processes associated with the denser cluster region seem to have caused accelerated size growth in quiescent galaxies prior to z = 1.6 and slower subsequent growth at z < 1.6 compared to galaxies in the lower density field. The quiescent cluster galaxies at z = 1.6 have higher ellipticities compared to lower redshift samples at fixed mass, and their surface-brightness profiles suggest that they contain extended stellar disks. We argue that the cluster galaxies require dissipationless (i.e., gas-poor or 'dry') mergers to reorganize the disk material and to match the relations for ellipticity, stellar mass, size, and color of early-type galaxies in z < 1 clusters.

Papovich, C.; Bassett, R.; Tran, K.-V; Finkelstein, S. L.; Finkelstein, K. D. [George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, and Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843-4242 (United States); Lotz, J. M.; Ferguson, H. C.; Koekemoer, A. M. [Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218 (United States); Van der Wel, A. [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117, Heidelberg (Germany); Bell, E. F. [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Conselice, C. J.; Haeussler, B. [School of Physics and Astronomy, University of Nottingham, Nottingham (United Kingdom); Dekel, A. [Racah Institute of Physics, The Hebrew University, Jerusalem 91904 (Israel); Dunlop, J. S. [Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh (United Kingdom); Guo, Yicheng [Astronomy Department, University of Massachusetts, Amherst, MA 01003 (United States); Faber, S. M.; Kocevski, D. D.; Koo, D. C.; McGrath, E. J. [UCO/Lick Observatory, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Farrah, D., E-mail: papovich@physics.tamu.edu [Astronomy Centre, University of Sussex, Falmer, Brighton (United Kingdom); and others

2012-05-10T23:59:59.000Z

171

Environmental Effects on Real-Space and Redshift-Space Galaxy Clustering  

E-Print Network [OSTI]

Galaxy formation inside dark matter halos, as well as the halo formation itself, can be affected by large-scale environments. Evaluating the imprints of environmental effects on galaxy clustering is crucial for precise cosmological constraints with data from galaxy redshift surveys. We investigate such an environmental impact on both real-space and redshift-space galaxy clustering statistics using a semi-analytic model derived from the Millennium Simulation. We compare clustering statistics from original SAM galaxy samples and shuffled ones with environmental influence on galaxy properties eliminated. Among the luminosity-threshold samples examined, the one with the lowest threshold luminosity (~0.2L_*) is affected by environmental effects the most, which has a ~10% decrease in the real-space two-point correlation function (2PCF) after shuffling. By decomposing the 2PCF into five different components based on the source of pairs, we show that the change in the 2PCF can be explained by the age and richness dependence of halo clustering. The 2PCFs in redshift space are found to change in a similar manner after shuffling. If the environmental effects are neglected, halo occupation distribution modeling of the real-space and redshift-space clustering may have a less than 6.5% systematic uncertainty in constraining beta from the most affected SAM sample and have substantially smaller uncertainties from the other, more luminous samples. We argue that the effect could be even smaller in reality. In the Appendix, we present a method to decompose the 2PCF, which can be applied to measure the two-point auto-correlation functions of galaxy sub-samples in a volume-limited galaxy sample and their two-point cross-correlation functions in a single run utilizing only one random catalog.

Ying Zu; Zheng Zheng; G. T. Zhu; Y. P. Jing

2007-12-20T23:59:59.000Z

172

DEXA'11, Toulouse, France, 31.08.2011 Sampling National Deep Web  

E-Print Network [OSTI]

DEXA'11, Toulouse, France, 31.08.2011 Sampling National Deep Web Denis Shestakov, fname-IP cluster random sampling Results Conclusions #12;Background Deep Web: web content behind search, the science and practice of deep web crawling is in its infancy" (in 'Web crawling', Olston&Najork, 2010) #12

Hammerton, James

173

Clusters in Hyper-Cubic Multi-Channel Satellite Imagery K.A. Hawick  

E-Print Network [OSTI]

satellites. Weather prediction it- self remains a challenging problem, not least due to the chaotic, but previously very successful GMS5 Japanese weather satellite[6]. Regularly sampled full-disk Earth image dataClusters in Hyper-Cubic Multi-Channel Satellite Imagery K.A. Hawick Computer Science, Massey

Hawick, Ken

174

Host-IP Clustering Technique for Deep Web Characterization Denis Shestakov  

E-Print Network [OSTI]

Host-IP Clustering Technique for Deep Web Characterization Denis Shestakov Department of Media databases. This part of the Web, known as the deep Web, is to date relatively unexplored and even major are aimed at more accurate estimation of main parameters of the deep Web by sampling one national web domain

Hammerton, James

175

Sample Proficiency Test exercise  

SciTech Connect (OSTI)

The current format of the OPCW proficiency tests has multiple sets of 2 samples sent to an analysis laboratory. In each sample set, one is identified as a sample, the other as a blank. This method of conducting proficiency tests differs from how an OPCW designated laboratory would receive authentic samples (a set of three containers, each not identified, consisting of the authentic sample, a control sample, and a blank sample). This exercise was designed to test the reporting if the proficiency tests were to be conducted. As such, this is not an official OPCW proficiency test, and the attached report is one method by which LLNL might report their analyses under a more realistic testing scheme. Therefore, the title on the report ''Report of the Umpteenth Official OPCW Proficiency Test'' is meaningless, and provides a bit of whimsy for the analyses and readers of the report.

Alcaraz, A; Gregg, H; Koester, C

2006-02-05T23:59:59.000Z

176

Reactive cluster model of metallic glasses  

SciTech Connect (OSTI)

Though discovered more than a half century ago metallic glasses remain a scientific enigma. Unlike crystalline metals, characterized by short, medium, and long-range order, in metallic glasses short and medium-range order persist, though long-range order is absent. This fact has prompted research to develop structural descriptions of metallic glasses. Among these are cluster-based models that attribute amorphous structure to the existence of clusters that are incommensurate with crystalline periodicity. Not addressed, however, are the chemical factors stabilizing these clusters and promoting their interconnections. We have found that glass formers are characterized by a rich cluster chemistry that above the glass transformation temperature promotes exchange as well as static and vibronic sharing of atoms between clusters. The vibronic mechanism induces correlated motions between neighboring clusters and we hypothesize that the distance over which these motions are correlated mediates metallic glass stability and influences critical cooling rates.

Jones, Travis E. [Molecular Theory Group, Colorado School of Mines, Golden, Colorado 80401 (United States) [Molecular Theory Group, Colorado School of Mines, Golden, Colorado 80401 (United States); School of Physics, The University of Sydney, Sydney, New South Wales 2006 (Australia); Miorelli, Jonathan; Eberhart, Mark E. [Molecular Theory Group, Colorado School of Mines, Golden, Colorado 80401 (United States)] [Molecular Theory Group, Colorado School of Mines, Golden, Colorado 80401 (United States)

2014-02-28T23:59:59.000Z

177

Massive Stellar Clusters in Interacting Galaxies  

E-Print Network [OSTI]

Massive clusters are now seen to form easily in interacting and merging galaxies, making these excellent environments for studying the properties of young clusters. New observations of the Antennae (NGC 4038/39) show that the most luminous young clusters do not have a measurable tidal radius. Most observations suggest that the luminosity function (LF) and mass functions of young clusters are single power laws. However, there are many uncertainties at the faint end of the LF. For example, contamination from massive stars may be important. The shape and evolution of the LF, and more fundamentally, the mass function, of massive clusters had implications for our understanding of both the formation and the destruction of massive stellar clusters.

B. W. Miller

1999-12-21T23:59:59.000Z

178

Toward Understanding Environmental Effects in SDSS Clusters  

E-Print Network [OSTI]

We find clusters and superclusters of galaxies using the Data Release 1 of the Sloan Digital Sky Survey. We determine the luminosity function of clusters and find that clusters in a high-density environment have a luminosity a factor of ~5 higher than in a low-density environment. We also study clusters and superclusters in numerical simulations. Simulated clusters in a high-density environment are also more massive than those in a low-density environment. Comparison of the density distribution at various epochs in simulations shows that in large low-density regions (voids) dynamical evolution is very slow and stops at an early epoch. In contrast, in large regions of higher density (superclusters) dynamical evolution starts early and continues until the present; here particles cluster early, and by merging of smaller groups very rich systems of galaxies form.

J. Einasto; E. Tago; M. Einasto; E. Saar; I. Suhhonenko; P. Hein"am"aki; G. Huetsi; D. L. Tucker

2004-11-09T23:59:59.000Z

179

X-ray spectroscopy of manganese clusters  

SciTech Connect (OSTI)

Much of this thesis represents the groundwork necessary in order to probe Mn clusters more productively than with conventional Mn K-edge XAS and is presented in Part 1. Part 2 contains the application of x-ray techniques to Mn metalloproteins and includes a prognosis at the end of each chapter. Individual Mn oxidation states are more readily distinguishable in Mn L-edge spectra. An empirical mixed valence simulation routine for determining the average Mn oxidation state has been developed. The first Mn L-edge spectra of a metalloprotein were measured and interpreted. The energy of Mn K{beta} emission is strongly correlated with average Mn oxidation state. K{beta} results support oxidation states of Mn(III){sub 2}(IV){sub 2} for the S{sub 1} state of Photosystem II chemical chemically reduced preparations contain predominantly Mn(II). A strength and limitation of XAS is that it probes all of the species of a particular element in a sample. It would often be advantageous to selectively probe different forms of the same element. The first demonstration that chemical shifts in x-ray fluorescence energies can be used to obtain oxidation state-selective x-ray absorption spectra is presented. Spin-dependent spectra can also be used to obtain a more simplified picture of local structure. The first spin-polarized extended x-ray absorption fine structure using Mn K{beta} fluorescence detection is shown.

Grush, M.M. [Univ. of California, Davis, CA (United States). Dept. of Applied Science; [Lawrence Berkeley National Lab., CA (United States). Energy and Environment Div.

1996-06-01T23:59:59.000Z

180

Seismic constraints on open clusters  

E-Print Network [OSTI]

We derive knowledge on the global and structural parameters of low-mass stars using asteroseismology and taking advantage of the stellar collective behavior within open clusters. We build stellar models and compute the seismic signal expected from main sequence objects in the 0.8-1.6 Msun range. We first evaluate apparent magnitudes and oscillations-induced luminosity fluctuations expected in the Hyades, the Pleiades and the alpha Persei clusters. The closest cluster presents a feasible challenge to observational asteroseismology in the present and near future. We combine seismological and classical computations to address three questions: what can be inferred about 1) mass, 2) composition and 3) extension of outer convection zones of solar analogs in the Hyades. The first issue relies on the strong sensitivity of the large separation to mass. Then large separations and second differences are used to respectively constrain metal and helium fractions in the Hyades.When plotted for several masses, the relation of effective temperature vs large separation is found to be strongly dependent on the metal content. Besides this the second difference main modulation is related to the second ionization of helium.The second difference modulations are also partly due to the discontinuity in stellar stratification at the convective envelope / radiative core transition. They permit direct insight in the stellar structure. We compute acoustic radii of the convective bases for different values of the mixing length theoryparameter alpha_MLT in convection modelling, i.e. different convective efficiency in the superadiabatic layers. For a given effectivetemperature we show that the acoustic radius changes with convection efficiency.

L. Piau; J. Ballot; S. Turck-Chieze

2005-03-07T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Systematic sampling with errors in sample locations  

Science Journals Connector (OSTI)

......truncation points 0 and 2 and standard deviation = 0 05 (middle...distributed with density h. Standard renewal theory yields...systematic sampling: a review of Matheron's transitive...Trans. Inst. Econ. Mining 59, 147. GUAL-ARNAU...methods. J. Statist. Plan. Infer. 77, 263279......

Johanna Ziegel; Adrian Baddeley; Karl-Anton Dorph-Petersen; Eva B. Vedel Jensen

2010-03-01T23:59:59.000Z

182

STAR CLUSTER COMPLEXES AND THE HOST GALAXY IN THREE H II GALAXIES: Mrk 36, UM 408, AND UM 461  

SciTech Connect (OSTI)

We present a stellar population study of three H II galaxies (Mrk 36, UM 408, and UM 461) based on the analysis of new ground-based high-resolution near-infrared J, H, and K{sub p} broadband and Br{gamma} narrowband images obtained with Gemini/NIRI. We identify and determine the relative ages and masses of the elementary star clusters and/or star cluster complexes of the starburst regions in each of these galaxies by comparing the colors with evolutionary synthesis models that include the contribution of stellar continuum, nebular continuum, and emission lines. We found that the current star cluster formation efficiency in our sample of low-luminosity H II galaxies is {approx}10%. Therefore, most of the recent star formation is not in massive clusters. Our findings seem to indicate that the star formation mode in our sample of galaxies is clumpy, and that these complexes are formed by a few massive star clusters with masses {approx}>10{sup 4} M{sub Sun }. The age distribution of these star cluster complexes shows that the current burst started recently and likely simultaneously over short timescales in their host galaxies, triggered by some internal mechanism. Finally, the fraction of the total cluster mass with respect to the low surface brightness (or host galaxy) mass, considering our complete range in ages, is less than 1%.

Lagos, P. [Centro de Astrofisica da Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal); Telles, E. [Observatorio Nacional, Rua Jose Cristino, 77, Rio de Janeiro 20921-400 (Brazil); Nigoche-Netro, A. [Instituto de Astrofisica de Andalucia (IAA), Glorieta de la Astronomia s/n, 18008 Granada (Spain); Carrasco, E. R., E-mail: plagos@astro.up.pt, E-mail: etelles@on.br, E-mail: nigoche@iaa.es, E-mail: rcarrasco@gemini.edu [Gemini Observatory/AURA, Southern Operations Center, Casilla 603, La Serena (Chile)

2011-11-15T23:59:59.000Z

183

Completion report for Well Cluster ER-20-5  

SciTech Connect (OSTI)

The Well Cluster ER-20-5 drilling and completion project was conducted for the US Department of Energy, Nevada Operations Office (DOE/NV), in support of the Nevada Environmental Restoration Project at the Nevada Test Site (NTS) in Nye County, Nevada. Its primary tasks include collecting geological, geophysical, hydrological, and water chemistry data from new and existing wells to define groundwater quality in addition to pathways and rates of groundwater migration. A program of drilling wells near the sites of selected underground nuclear tests (near-field drilling) was implemented to obtain site-specific data about the nature and extent of migration of radionuclides that might have been produced by an underground nuclear explosion. Well Cluster ER-20-5 is the first near-field drilling project initiated at the NTS. This document presents construction data and summarizes the scientific data gathered during the drilling and well-installation phases for all three holes drilled at Well Cluster ER-20-5. Some of this information is preliminary and unprocessed, but was released so that drilling, geotechnical, well design, and completion data could be rapidly disseminated. Additional information about water levels, aquifer testing, and groundwater sampling will be reported after any of this work is performed. Any additional geologic and/or geophysical investigations conducted for this project is described in one or more analysis and interpretation reports. The lithologic and stratigraphic logs, however, are provided in final form.

NONE

1997-03-01T23:59:59.000Z

184

Deriving the mass distribution of M87 from globular clusters  

E-Print Network [OSTI]

We describe a maximum-likelihood method for determining the mass distribution in spherical stellar systems from the radial velocities of a population of discrete test particles. The method assumes a parametric form for the mass distribution and a non-parametric two-integral distribution function. We apply the method to a sample of 161 globular clusters in M87. We find that the mass within 32 kpc is $(2.4\\pm0.6)\\times 10^{12} $M${_\\odot}$, and the exponent of the density profile $\\rho\\propto r^{-\\alpha}$ in the range 10-100 kpc is $\\alpha=1.6\\pm0.4$.The energy distribution suggests a few kinematically distinct groups of globular clusters. The anisotropy of the globular-cluster velocity distribution cannot be determined reliably with the present data. Models fitted to an NFW potential yield similar mass estimates but cannot constrain the concentration radius $r_c$ in the range 10-500 kpc.

Xiaoan Wu; Scott Tremaine

2006-01-23T23:59:59.000Z

185

The Open Cluster Distance Scale: A New Empirical Approach  

E-Print Network [OSTI]

We present new BVRI photometry for a sample of 54 local G and K stars with accurate Hipparcos parallaxes in the metallicity range -0.4 solar abundance determined from spectroscopy, we find significant disagreement at a level similar to that found by other MS-fitting studies. However, the colour-colour relationship for both these clusters suggests that their metallicity is significantly subsolar. Since the MS-fitting method relies on matching the cluster colours to a template MS, we argue that, when applying this method, the appropriate metallicity to adopt is the photometric subsolar one, not the solar abundance indicated by spectroscopy. Adopting photometric metallicities for all 4 clusters, we find complete agreement with the Hipparcos results and hence we conclude that the mismatch between the spectroscopic and photometric abundances for the Pleiades and NGC 2516 is responsible for the discrepancies in distance estimates found by previous studies. The origin of this mismatch in abundance scales remains an unsolved problem and some possible causes are discussed.

Susan M. Percival; Maurizio Salaris; David Kilkenny

2003-01-13T23:59:59.000Z

186

Relational Sequence Clustering for Aggregating Similar Agents  

E-Print Network [OSTI]

Relational Sequence Clustering for Aggregating Similar Agents Grazia Bombini, Nicola Di Mauro;2 Grazia Bombini, Nicola Di Mauro, Stefano Ferilli, and Floriana Esposito image segmentation and pattern

Di Mauro, Nicola

187

Wide field imaging of distant clusters  

E-Print Network [OSTI]

Wide field imaging is key to understanding the build-up of distant clusters and their galaxy population. By focusing on the so far unexplored outskirts of clusters, where infalling galaxies first hit the cluster potential and the hot intracluster medium, we can help separate cosmological field galaxy evolution from that driven by environment. I present a selection of recent advancements in this area, with particular emphasis on Hubble Space Telescope wide field imaging, for its superior capability to deliver galaxy morphologies and precise shear maps of distant clusters.

T. Treu

2004-08-05T23:59:59.000Z

188

Multiphoton ionization of large water clusters  

SciTech Connect (OSTI)

Water clusters are multimers of water molecules held together by hydrogen bonds. In the present work, multiphoton ionization in the UV range coupled with time of flight mass spectrometry has been applied to water clusters with up to 160 molecules in order to obtain information on the electronic states of clusters of different sizes up to dimensions that can approximate the bulk phase. The dependence of ion intensities of water clusters and their metastable fragments produced by laser ionization at 355 nm on laser power density indicates a (3+1)-photon resonance-enhanced multiphoton ionization process. It also explains the large increase of ionization efficiency at 355 nm compared to that at 266 nm. Indeed, it was found, by applying both nanosecond and picosecond laser ionization with the two different UV wavelengths, that no water cluster sequences after n = 9 could be observed at 266 nm, whereas water clusters up to m/z 2000 Th in reflectron mode and m/z 3000 Th in linear mode were detected at 355 nm. The agreement between our findings on clusters of water, especially true in the range with n > 10, and reported data for liquid water supports the hypothesis that clusters above a critical dimension can approximate the liquid phase. It should thus be possible to study clusters just above 10 water molecules, for getting information on the bulk phase structure.

Apicella, B., E-mail: apicella@irc.cnr.it [Combustion Research Institute, IRC–C.N.R., P.le Tecchio 80, 80125 Napoli (Italy); Li, X. [Key Laboratory of Power Machinery and Engineering, Ministry of Education, Shanghai Jiao Tong University, Shanghai 200240 (China); Passaro, M. [CNISM and Chemical Engineering, Materials and Industrial Production Department, University of Naples “Federico II,” P.le Tecchio 80, 80125 Napoli (Italy); Spinelli, N. [CNISM and Physics Department, University of Naples “Federico II,” Via Cintia, 80124 Napoli (Italy); Wang, X. [SPIN–C.N.R., Via Cintia, 80124 Napoli (Italy)

2014-05-28T23:59:59.000Z

189

Magnetic Fields in Clusters of Galaxies  

E-Print Network [OSTI]

A brief overview about our knowledge on galaxy cluster magnetic fields is provided. Emphasize is given to the mutual dependence of our knowledge on relativistic particles in galaxy clusters and the magnetic field strength. Furthermore, we describe efforts to measure magnetic field strengths, characteristic length-scales, and power-spectra with reliable accuracy. An interpretation of these results in terms of non-helical dynamo theory is given. If this interpretation turns out to be correct, the understanding of cluster magnetic fields is directly connected to our understanding of intra-cluster turbulence.

Torsten A. Ensslin; Corina Vogt; Christoph Pfrommer

2005-01-17T23:59:59.000Z

190

Stable Oxide Nanoparticle Clusters Obtained by Complexation  

E-Print Network [OSTI]

We report on the electrostatic complexation between polyelectrolyte-neutral copolymers and oppositely charged 6 nm-crystalline nanoparticles. For two different dispersions of oxide nanoparticles, the electrostatic complexation gives rise to the formation of stable nanoparticle clusters in the range 20 - 100 nm. It is found that inside the clusters, the particles are pasted together by the polyelectrolyte blocks adsorbed on their surface. Cryo-transmission electronic microscopy allows to visualize the clusters and to determine the probability distributions functions in size and in aggregation number. The comparison between light scattering and cryo-microscopy results suggests the existence of a polymer brush around the clusters.

J. -F. Berret; A. Sehgal; M. Morvan; O. Sandre; A. Vacher; M. Airiau

2006-08-08T23:59:59.000Z

191

Optimization of synchronization in gradient clustered networks  

E-Print Network [OSTI]

We consider complex clustered networks with a gradient structure, where sizes of the clusters are distributed unevenly. Such networks describe more closely actual networks in biophysical systems and in technological applications than previous models. Theoretical analysis predicts that the network synchronizability can be optimized by the strength of the gradient field but only when the gradient field points from large to small clusters. A remarkable finding is that, if the gradient field is sufficiently strong, synchronizability of the network is mainly determined by the properties of the subnetworks in the two largest clusters. These results are verified by numerical eigenvalue analysis and by direct simulation of synchronization dynamics on coupled-oscillator networks.

Xingang Wang; Liang Huang; Ying-Cheng Lai; Choy Heng Lai

2007-11-23T23:59:59.000Z

192

Fragmentation Energetics of Clusters Relevant to Atmospheric...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

are also important. However, few laboratory experiments address the kinetics or thermodynamics of acid and base incorporation into small clusters. This work utilizes a Fourier...

193

Cluster Observations with the South Pole Telescope  

E-Print Network [OSTI]

Cluster Survey Studies of the Dark Energy. 2004. A.J.C. dadark energy equation of state, and demonstrates the utility of a redshift-independent survey

Plagge, Thomas Jeffrey

2009-01-01T23:59:59.000Z

194

A Survey of Open Clusters in the u'g'r'i'z' Filter System. 3. Results for the Cluster NGC 188  

SciTech Connect (OSTI)

The authors continue the series of papers describing the results of a photometric survey of open star clusters, primarily in the southern hemisphere, taken in the u'g'r'i'z' filter system. The entire observed sample covered more than 100 clusters, but here they present data only on NGC 188, which is one of the oldest open clusters known in the Milky Way. They fit the Padova theoretical isochrones to the data. Assuming a solar metallicity for NGC 188, they find a distance of 1700 {+-} 100 pc, an age of 7.5 {+-} 0.7 Gyr, and a reddening E(B-V) of 0.025 {+-} 0.005. This yields a distance modulus of 11.23 {+-} 0.14.

Fornal, Bartosz; Tucker, Douglas L.; Smith, J.Allyn; Allam, Sahar S.; Rider, Cristin J.; Sung, Hwankyung; /Jagiellonian U. /Fermilab /Austin Peay State U. /Wyoming U. /Johns Hopkins U. /Sejong U.

2006-11-01T23:59:59.000Z

195

A Survey of Open Clusters in the u'g'r'i'z' Filter System: III. Results for the Cluster NGC 188  

E-Print Network [OSTI]

We continue our series of papers describing the results of a photometric survey of open star clusters, primarily in the southern hemisphere, taken in the u'g'r'i'z' filter system. The entire observed sample covered more than 100 clusters, but here we present data only on NGC 188, which is one of the oldest open clusters known in the Milky Way. We fit the Padova theoretical isochrones to our data. Assuming a solar metallicity for NGC 188, we find a distance of 1700+/-100 pc, an age of 7.5+/-0.7 Gyr, and a reddening E(B-V) of 0.025+/-0.005. This yields a distance modulus of 11.23+/-0.14.

Bartosz Fornal; Douglas L. Tucker; J. Allyn Smith; Sahar S. Allam; Cristin J. Rider; Hwankyung Sung

2006-11-29T23:59:59.000Z

196

Assessing respondent-driven sampling  

Science Journals Connector (OSTI)

...convenience sampling through the internet versus respondent driven sampling...in Social Networks, Drug Abuse, and HIV Transmission , eds...5) MSM Tallinn, Estonia Internet convenience sampling...convenience sampling through the internet versus respondent driven sampling...

Sharad Goel; Matthew J. Salganik

2010-01-01T23:59:59.000Z

197

Reactions of cobalt clusters with water and ammonia: Implications for cluster structure  

SciTech Connect (OSTI)

Reactions of cobalt clusters in the 6 to 150 atom size range with water and ammonia are used to probe cluster geometrical structure. Clusters saturated with ammonia are found in several isomeric forms in much of this size region, including a structure based on icosahedral packing for clusters having 50 to 120 atoms. The variations with cluster size of the binding energy for a single water molecule provide evidence for icosahedral structure of the bare cobalt clusters in the same size range seen for the ammoniated clusters. However, both probes suggest that in many cases the bare clusters also have multiple isomers. The evidence for icosahedral structure in the bare and ammoniated clusters disappears above [similar to]120 atoms and is clearly not seen at the third icosahedral shell closing at 147 atoms. Comparison with earlier studies of hydrogenated cobalt clusters and with bare and hydrogenated nickel clusters is made. Reasons for the failure to form the closed-shell 147 atom icosahedral cluster are discussed.

Parks, E.K.; Klots, T.D.; Winter, B.J.; Riley, S.J. (Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States))

1993-10-15T23:59:59.000Z

198

KEYWORDS: geospatial clustering, web service, Web GIS, spatial data mining, clustering 1 INTRODUCTION  

E-Print Network [OSTI]

1 KEYWORDS: geospatial clustering, web service, Web GIS, spatial data mining, clustering 1-poor. Unprecedented amounts of spatial data are gathered quickly and easily through various methods, such as sensorsClustering offers an API and follows the OGC standard data format for spatial data exchange. #12;2 connectivity

199

An Investigation of Linguistic Features and Clustering Algorithms for Topical Document Clustering  

E-Print Network [OSTI]

An Investigation of Linguistic Features and Clustering Algorithms for Topical Document Clustering of document clustering. A sta­ tistical model for combining similarity information from mul­ tiple sources is described and applied to DARPA's Topic De­ tection and Tracking phase 2 (TDT2) data. This model, based

Gravano, Luis

200

An Investigation of Linguistic Features and Clustering Algorithms for Topical Document Clustering  

E-Print Network [OSTI]

An Investigation of Linguistic Features and Clustering Algorithms for Topical Document Clustering of document clustering. A sta- tistical model for combining similarity information from mul- tiple sources is described and applied to DARPA's Topic De- tection and Tracking phase 2 (TDT2) data. This model, based

Gravano, Luis

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

The Birmingham-CfA cluster scaling project - III: entropy and similarity in galaxy systems  

E-Print Network [OSTI]

We examine profiles and scaling properties of the entropy of the intergalactic gas in a sample of 66 virialized systems, ranging in mass from single elliptical galaxies to rich clusters, for which we have resolved X-ray temperature profiles. Some of the properties we derive appear to be inconsistent with any of the models put forward to explain the breaking of self-similarity in the baryon content of clusters. In particular, the entropy profiles, scaled to the virial radius, are broadly similar in form across the sample, apart from a normalization factor which differs from the simple self-similar scaling with temperature. Low mass systems do not show the large isentropic cores predicted by preheating models, and the high entropy excesses reported at large radii in groups by Finoguenov et al (2002) are confirmed, and found to extend even to moderately rich clusters. We discuss the implications of these results for the evolutionary history of the hot gas in clusters, and suggest that preheating may affect the entropy of intracluster gas primarily by reducing the density of material accreting into groups and clusters along cosmic filaments.

T. J. Ponman; A. J. R. Sanderson; A. Finoguenov

2003-04-02T23:59:59.000Z

202

Near-infrared evolution of brightest cluster galaxies in the most X-ray luminous clusters since z=1  

E-Print Network [OSTI]

We investigate the near infrared evolution of brightest cluster galaxies (BCGs) from a sample of rich galaxy clusters since z=1. By employing an X-ray selection of Lx>1e44 erg s-1 we limit environmental effects by selecting BCGs in comparably high density regions. We find a positive relationship between X-ray and near-infrared luminosity for BCGs in clusters with Lx>5e44 erg s-1. Applying a correction for this relation we reduce the scatter in the BCG absolute magnitude by a factor of 30%. The near-infrared J-K colour evolution demonstrates that the stellar population in BCGs has been in place since at least z=2 and that we expect a shorter period of star formation than that predicted by current hierarchical merger models. We also confirm that there is a relationship between `blue' J-K colour and the presence of BCG emission lines associated with star formation in cooling flows.

J. P. Stott; A. C. Edge; G. P. Smith; A. M. Swinbank; H. Ebeling

2007-12-04T23:59:59.000Z

203

September 2004 Water Sampling  

Office of Legacy Management (LM)

Green River, Utah, Disposal Site Green River, Utah, Disposal Site August 2013 LMS/GRN/S00613 This page intentionally left blank U.S. Department of Energy DVP-June 2013, Green River, Utah August 2013 RIN 13065402 Page i Contents Sampling Event Summary ...............................................................................................................1 Data Assessment Summary ..............................................................................................................7 Water Sampling Field Activities Verification Checklist .............................................................9 Laboratory Performance Assessment ........................................................................................11 Sampling Quality Control Assessment ......................................................................................18

204

Sampled data lattice filters  

E-Print Network [OSTI]

SAMPLED DATA LATTICE FILTERS A Thesis by WILLIAM TERRY THRIFT III Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE December 1979 Major Subfect...: Electrical Engineering SAMPLED DATA LATTICE FILTERS A Thesis by WILLIAM TERRY THRIFT III Approved as to style and content by: (Chair an of Committee) (Hea f Department) (Member) (Member) (Member) (Member) December 1979 ABSTRACT Sampled Data...

Thrift, William Terry

2012-06-07T23:59:59.000Z

205

September 2004 Water Sampling  

Office of Legacy Management (LM)

sample recovery not within control limits. Organic: Tentatively identified compound (TIC). P > 25% difference in detected pesticide or Aroclor concentrations between 2 columns....

206

EMSL - sediment samples  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

sediment-samples en Diffusional Motion of Redox Centers in Carbonate Electrolytes . http:www.emsl.pnl.govemslwebpublicationsdiffusional-motion-redox-centers-carbonate-electrol...

207

September 2004 Water Sampling  

Office of Legacy Management (LM)

conducted in accordance with the Sampling and Analysis Plan for the U. S. Department of Energy Office of Legacy Management Sites (LMSPROS04351, continually updated). Monitoring...

208

September 2004 Water Sampling  

Office of Legacy Management (LM)

4 Groundwater and Surface Water Sampling at the Gunnison, Colorado, Processing Site September 2014 LMSGUPS00414 This page intentionally left blank U.S. Department of Energy...

209

September 2004 Water Sampling  

Office of Legacy Management (LM)

4 Groundwater and Surface Water Sampling at the Slick Rock, Colorado, Processing Sites December 2014 LMSSRWSRES00914 This page intentionally left blank U.S. Department of Energy...

210

uvby-Hbeta CCD photometry and membership segregation of the open cluster NGC 2548; Gaps in the Main Sequence of open clusters  

E-Print Network [OSTI]

Deep CCD photometry in the uvby-Hbeta intermediate-band system is presented for the cluster NGC 2548 (M 48). A complete membership analysis based on astrometric and photometric criteria is applied. The photometric analysis of a selected sample of stars yields a reddening value of E(b-y)=0.06\\pm0.03, a distance modulus of V_0-M_V=9.3\\pm0.5 (725 pc) and a metallicity of [Fe/H]= -0.24\\pm0.27. Through isochrone fitting we find an age of log t = 8.6\\pm0.1 (400 Myr). Our optical photometry and JHK from 2MASS are combined to derive effective temperatures of cluster member stars. The effective temperature distribution along the main sequence of the cluster shows several gaps. A test to study the significance of these gaps in the main sequence of the HR diagram has been applied. The method is also applied to several other open clusters (Pleiades, Hyades, NGC 1817 and M 67) to construct a sequence of metallicities and ages. The comparison of the results of each cluster gives four gaps with high significance (one of the...

Balaguer-Nuńez, L; Galadi-Enriquez, D

2004-01-01T23:59:59.000Z

211

THE HST/ACS COMA CLUSTER SURVEY. VIII. BARRED DISK GALAXIES IN THE CORE OF THE COMA CLUSTER  

SciTech Connect (OSTI)

We use high-resolution ({approx}0.''1) F814W Advanced Camera for Surveys (ACS) images from the Hubble Space Telescope ACS Treasury survey of the Coma cluster at z {approx} 0.02 to study bars in massive disk galaxies (S0s), as well as low-mass dwarf galaxies in the core of the Coma cluster, the densest environment in the nearby universe. Our study helps to constrain the evolution of bars and disks in dense environments and provides a comparison point for studies in lower density environments and at higher redshifts. Our results are: (1) we characterize the fraction and properties of bars in a sample of 32 bright (M{sub V} {approx}< -18, M{sub *} > 10{sup 9.5} M{sub Sun }) S0 galaxies, which dominate the population of massive disk galaxies in the Coma core. We find that the measurement of a bar fraction among S0 galaxies must be handled with special care due to the difficulty in separating unbarred S0s from ellipticals, and the potential dilution of the bar signature by light from a relatively large, bright bulge. The results depend sensitively on the method used: the bar fraction for bright S0s in the Coma core is 50% {+-} 11%, 65% {+-} 11%, and 60% {+-} 11% based on three methods of bar detection, namely, strict ellipse fit criteria, relaxed ellipse fit criteria, and visual classification. (2) We compare the S0 bar fraction across different environments (the Coma core, A901/902, and Virgo) adopting the critical step of using matched samples and matched methods in order to ensure robust comparisons. We find that the bar fraction among bright S0 galaxies does not show a statistically significant variation (within the error bars of {+-}11%) across environments which span two orders of magnitude in galaxy number density (n {approx} 300-10,000 galaxies Mpc{sup -3}) and include rich and poor clusters, such as the core of Coma, the A901/902 cluster, and Virgo. We speculate that the bar fraction among S0s is not significantly enhanced in rich clusters compared to low-density environments for two reasons. First, S0s in rich clusters are less prone to bar instabilities as they are dynamically heated by harassment and are gas poor as a result of ram pressure stripping and accelerated star formation. Second, high-speed encounters in rich clusters may be less effective than slow, strong encounters in inducing bars. (3) We also take advantage of the high resolution of the ACS ({approx}50 pc) to analyze a sample of 333 faint (M{sub V} > -18) dwarf galaxies in the Coma core. Using visual inspection of unsharp-masked images, we find only 13 galaxies with bar and/or spiral structure. An additional eight galaxies show evidence for an inclined disk. The paucity of disk structures in Coma dwarfs suggests that either disks are not common in these galaxies or that any disks present are too hot to develop instabilities.

Marinova, Irina; Jogee, Shardha; Weinzirl, Tim [Department of Astronomy, University of Texas at Austin, Austin, TX (United States); Erwin, Peter [Max-Planck-Insitut fuer extraterrestrische Physik, Giessenbachstrasse, 85748 Garching (Germany); Trentham, Neil [Institute of Astronomy, Madingley Road, Cambridge, CB3 0HA (United Kingdom); Ferguson, Henry C.; Goudfrooij, Paul [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Hammer, Derek [Department of Physics and Astronomy, Johns Hopkins, Baltimore, MD 21218 (United States); Den Brok, Mark; Peletier, Reynier F.; Kleijn, Gijs V. [Kapteyn Astronomical Institute, University of Groningen, Groningen (Netherlands); Graham, Alister W. [Centre for Astrophysics and Supercomputing, Swinburne University, Hawthorn (Australia); Carter, David; Mouhcine, Mustapha [Astrophysics Research Institute, Liverpool John Moores University, Birkenhead (United Kingdom); Balcells, Marc [Instituto de Astrofisica de Canarias, 38200 La Laguna, Tenerife (Spain); Guzman, Rafael; Hoyos, Carlos [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States); Mobasher, Bahram [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); Peng, Eric W., E-mail: marinova@astro.as.utexas.edu, E-mail: sj@astro.as.utexas.edu [Department of Astronomy, Peking University, Beijing 100871 (China)

2012-02-20T23:59:59.000Z

212

THE DENSITY PROFILES OF MASSIVE, RELAXED GALAXY CLUSTERS. II. SEPARATING LUMINOUS AND DARK MATTER IN CLUSTER CORES  

SciTech Connect (OSTI)

We present stellar and dark matter (DM) density profiles for a sample of seven massive, relaxed galaxy clusters derived from strong and weak gravitational lensing and resolved stellar kinematic observations within the centrally located brightest cluster galaxies (BCGs). In Paper I of the series, we demonstrated that the total density profile derived from these data, which span three decades in radius, is consistent with numerical DM-only simulations at radii {approx}> 5-10 kpc, despite the significant contribution of stellar material in the core. Here, we decompose the inner mass profiles of these clusters into stellar and dark components. Parameterizing the DM density profile as a power law {rho}{sub DM}{proportional_to}r {sup -{beta}} on small scales, we find a mean slope ({beta}) = 0.50 {+-} 0.10(random){sup +0.14} {sub -0.13}(systematic). Alternatively, cored Navarro-Frenk-White (NFW) profiles with (log r {sub core}/kpc) = 1.14 {+-} 0.13{sup +0.14} {sub -0.22} provide an equally good description. These density profiles are significantly shallower than canonical NFW models at radii {approx}< 30 kpc, comparable to the effective radii of the BCGs. The inner DM profile is correlated with the distribution of stars in the BCG, suggesting a connection between the inner halo and the assembly of stars in the central galaxy. The stellar mass-to-light ratio inferred from lensing and stellar dynamics is consistent with that inferred using stellar population synthesis models if a Salpeter initial mass function is adopted. We compare these results to theories describing the interaction between baryons and DM in cluster cores, including adiabatic contraction models and the possible effects of galaxy mergers and active galactic nucleus feedback, and evaluate possible signatures of alternative DM candidates.

Newman, Andrew B.; Ellis, Richard S. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, MS 249-17, Pasadena, CA 91125 (United States)] [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, MS 249-17, Pasadena, CA 91125 (United States); Treu, Tommaso; Sand, David J., E-mail: anewman@astro.caltech.edu [Department of Physics, University of California, Santa Barbara, CA 93106 (United States)

2013-03-01T23:59:59.000Z

213

THE APM CLUSTER SURVEY: CLUSTER DETECTION AND LARGE-SCALE STRUCTURE  

E-Print Network [OSTI]

The APM Cluster Survey was based on a modification of Abell's original classification scheme for galaxy clusters. Here we discuss the results of an investigation of the stability of the statistical properties of the cluster catalogue to changes in the selection parameters. For a poor choice of selection parameters we find clear indications of line-of-sight clusters, but there is a wide range of input parameters for which the statistical properties of the catalogue are stable. We conclude that clusters selected in this way are indeed useful as tracers of large-scale structure.

G. B. Dalton

1995-05-17T23:59:59.000Z

214

Query log driven web search results clustering  

Science Journals Connector (OSTI)

Different important studies in Web search results clustering have recently shown increasing performances motivated by the use of external resources. Following this trend, we present a new algorithm called Dual C-Means, which provides a theoretical background ... Keywords: automatic labeling, dual c-means, evaluation, web search results clustering

Jose G. Moreno; Gaël Dias; Guillaume Cleuziou

2014-07-01T23:59:59.000Z

215

Data Clustering: A Review Michigan State University  

E-Print Network [OSTI]

Data Clustering: A Review A.K. JAIN Michigan State University M.N. MURTY Indian Institute, East Lansing, MI 48824; M. Murty, Department of Computer Science and Automation, Indian Institute as a vector of measure- ments, or a point in a multidimensional space) into clusters based on similarity

Fiat, Amos

216

Functional Clustering in Nested Designs Abel Rodriguez  

E-Print Network [OSTI]

Functional Clustering in Nested Designs Abel Rodriguez University of California, Santa Cruz) and oceanography (Rodriguez et al., 2008a). Because functional data are inherently complex, functional clustering the principal points of random functions; James & Sugar (2003), who develop methods for sparsely sam- pled

West, Mike

217

Luminosity function of clusters of galaxies  

E-Print Network [OSTI]

The composite galaxy luminosity function (hereafter LF) of 39 Abell clusters of galaxies is derived by computing the statistical excess of galaxy counts in the cluster direction with respect to control fields. Due to the wide field coverage of the digitised POSS-II plates, we can measure field counts around each cluster in a fully homogeneous way. Furthermore, the availability of virtually unlimited sky coverage allows us to directly compute the LF errors without having to rely on the estimated variance of the background. The wide field coverage also allows us to derive the LF of the whole cluster, including galaxies located in the cluster outskirts. The global composite LF has a slope alpha ~ -1.1+/-0.2 with minor variations from blue to red filters, and M* ~ -21.7,-22.2,-22.4 mag (H_0=50 km/s/Mpc) in g, r and i filters, respectively. These results are in quite good agreement with several previous determinations and in particular with the LF determined for the inner region of a largely overlapping set of clusters, but derived making use of a completely different method for background subtraction. The similarity of the two LFs suggests the existence of minor differences between the LF in the cluster outskirts and in the central region, or a negligible contribution of galaxies in the cluster outskirts to the global LF.

M. Paolillo; S. Andreon; G. Longo; E. Puddu; R. R. Gal; R. Scaramella; S. G. Djorgovski; R. de Carvalho

2000-12-11T23:59:59.000Z

218

Cluster Parallel Loops Part I. Preliminaries  

E-Print Network [OSTI]

;14­2 BIG CPU, BIG DATA he massively parallel Bitcoin mining program in Chapter 13 still doesn't take full advantage of the cluster's parallel processing capabilities. Each Bitcoin mining task uses all the cores on just one node. So on the 10-node tardis cluster, I have to mine 10 or more Bitcoins to fully utilize

Kaminsky, Alan

219

Cool Gas in the Virgo Cluster?  

Science Journals Connector (OSTI)

...ASTROPHYSICS 32 , 277 ( 1994 ). • LIEU R , Discovery of 0.5 MK gas in the center of the Virgo Cluster , ASTROPHYSICAL JOURNAL...1) using data on the Virgo cluster taken with the Extreme Ultra-violet Explorer (EUVE). They found that the very soft x-ray...

Andrew C. Fabian

1996-03-01T23:59:59.000Z

220

Energy Accounting and Control on HPC clusters  

E-Print Network [OSTI]

Energy Accounting and Control on HPC clusters Yiannis Georgiou R&D Software Engineer #12;Objectives Issues that we wanted to deal with: Measure power and energy consumption on HPC clusters Attribute power and energy data to HPC components Calculate the energy consumption of jobs in the system Extract power

Lefèvre, Laurent

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Cluster Survey Studies of the Dark Energy  

E-Print Network [OSTI]

Galaxy cluster surveys are power tools for studying the dark energy. In principle, the equation of state parameter w of the dark energy and its time evolution can be extracted from large solid angle, high yield surveys that deliver tens of thousands of clusters. Robust constraints require accurate knowledge of the survey selection, and crude cluster redshift estimates must be available. A simple survey observable like the cluster flux is connected to the underlying cluster halo mass through a so--called mass--observable relation. The calibration of this mass--observable relation and its redshift evolution is a key challenge in extracting precise cosmological constraints. Cluster survey self--calibration is a technique for meeting this challenge, and it can be applied to large solid angle surveys. In essence, the cluster redshift distribution, the cluster power spectrum, and a limited number of mass measurements can be brought together to calibrate the survey and study the dark energy simultaneously. Additional survey information like the shape of the mass function and its evolution with redshift can then be used to test the robustness of the dark energy constraints.

Joseph J Mohr

2004-08-25T23:59:59.000Z

222

Sampling system and method  

DOE Patents [OSTI]

The present disclosure provides an apparatus and method for coupling conduit segments together. A first pump obtains a sample and transmits it through a first conduit to a reservoir accessible by a second pump. The second pump further conducts the sample from the reservoir through a second conduit.

Decker, David L.; Lyles, Brad F.; Purcell, Richard G.; Hershey, Ronald Lee

2013-04-16T23:59:59.000Z

223

Fundamental clusters in spatial 2×2 games  

Science Journals Connector (OSTI)

...holds but equation (17) does not, does the central site protect...apply: 764 Ch. Hauert Fundamental clusters in spatial 2...note that the reverse does not necessarily hold...powerful approximations to fundamental clusters. 3. CLUSTER...

2001-01-01T23:59:59.000Z

224

Biases on cosmological parameter estimators from galaxy cluster number counts  

E-Print Network [OSTI]

Sunyaev-Zel'dovich (SZ) surveys are promising probes of cosmology - in particular for Dark Energy (DE) -, given their ability to find distant clusters and provide estimates for their mass. However, current SZ catalogs contain tens to hundreds of objects and maximum likelihood estimators may present biases for such sample sizes. In this work we use the Monte Carlo approach to determine the presence of bias on cosmological parameter estimators from cluster abundance as a function of the area and depth of the survey, and the number of cosmological parameters fitted. Assuming perfect knowledge of mass and redshift some estimators have non-negligible biases. For example, the bias of $\\sigma_8$ corresponds to about $40%$ of its statistical error bar when fitted together with $\\Omega_c$ and $w_0$. Including a SZ mass-observable relation decreases the relevance of the bias, for the typical sizes of current surveys. The biases become negligible when combining the SZ data with other cosmological probes. However, we show that the biases from SZ estimators do not go away with increasing sample sizes and they may become the dominant source of error for an all sky survey at the South Pole Telescope (SPT) sensitivity. The results of this work validate the use of the current maximum likelihood methods for present SZ surveys, but highlight the need for further studies for upcoming experiments. [abridged

M. Penna-Lima; M. Makler; C. A. Wuensche

2013-12-16T23:59:59.000Z

225

2003 CBECS Sample Design  

U.S. Energy Information Administration (EIA) Indexed Site

Technical Information > Sample Design Technical Information > Sample Design How the Survey Was Conducted 2003 Commercial Buildings Energy Consumption Survey: Sample Design Introduction The Commercial Buildings Energy Consumption Survey (CBECS) is conducted quadrennially by the Energy Information Administration (EIA) to provide basic statistical information about energy consumption and expenditures in U.S. commercial buildings and information about energy-related characteristics of these buildings. The survey is based upon a sample of commercial buildings selected according to the sample design requirements described below. A “building,” as opposed to an “establishment,” is the basic unit of analysis for the CBECS because the building is the energy-consuming unit. The 2003 CBECS was the eighth survey conducted since 1979

226

Sample Changes and Issues  

U.S. Energy Information Administration (EIA) Indexed Site

Sample and Model Issues Sample and Model Issues Summary Our comprehensive review of the EIA 914 has confirmed that discrepancies can arise between estimates for December of one year and January of the next. These are most evident for Texas estimates between December 2008 and January 2009. Reports now available from HPDI show that production for all the companies we sampled in both 2008 and 2009 rose by about 60 million cubic feet per day (MMcf/d) in January and that total production in Texas rose by a similar amount. Our estimate was a decrease of 360 MMcf/d. Why the difference? Computationally, EIA-914 estimates depend on two factors: * Reports from the companies in the survey sample * An expansion factor to estimate total production from the sample's reported

227

On Spectral Clustering: Analysis and an algorithm  

E-Print Network [OSTI]

Despite many empirical successes of spectral clustering methods -- algorithms that cluster points using eigenvectors of matrices derived from the distances between the points -- there are several unresolved issues. First, there is a wide variety of algorithms that use the eigenvectors in slightly different ways. Second, many of these algorithms have no proof that they will actually compute a reasonable clustering. In this paper, we present a simple spectral clustering algorithm that can be implemented using a few lines of Matlab. Using tools from matrix perturbation theory, we analyze the algorithm, and give conditions under which it can be expected to do well. We also show surprisingly good experimental results on a number of challenging clustering problems.

Andrew Y. Ng; Michael I. Jordan; Yair Weiss

2001-01-01T23:59:59.000Z

228

Web document clustering using hyperlink structures  

SciTech Connect (OSTI)

With the exponential growth of information on the World Wide Web there is great demand for developing efficient and effective methods for organizing and retrieving the information available. Document clustering plays an important role in information retrieval and taxonomy management for the World Wide Web and remains an interesting and challenging problem in the field of web computing. In this paper we consider document clustering methods exploring textual information hyperlink structure and co-citation relations. In particular we apply the normalized cut clustering method developed in computer vision to the task of hyperdocument clustering. We also explore some theoretical connections of the normalized-cut method to K-means method. We then experiment with normalized-cut method in the context of clustering query result sets for web search engines.

He, Xiaofeng; Zha, Hongyuan; Ding, Chris H.Q; Simon, Horst D.

2001-05-07T23:59:59.000Z

229

Bipartite graph partitioning and data clustering  

SciTech Connect (OSTI)

Many data types arising from data mining applications can be modeled as bipartite graphs, examples include terms and documents in a text corpus, customers and purchasing items in market basket analysis and reviewers and movies in a movie recommender system. In this paper, the authors propose a new data clustering method based on partitioning the underlying biopartite graph. The partition is constructed by minimizing a normalized sum of edge weights between unmatched pairs of vertices of the bipartite graph. They show that an approximate solution to the minimization problem can be obtained by computing a partial singular value decomposition (SVD) of the associated edge weight matrix of the bipartite graph. They point out the connection of their clustering algorithm to correspondence analysis used in multivariate analysis. They also briefly discuss the issue of assigning data objects to multiple clusters. In the experimental results, they apply their clustering algorithm to the problem of document clustering to illustrate its effectiveness and efficiency.

Zha, Hongyuan; He, Xiaofeng; Ding, Chris; Gu, Ming; Simon, Horst D.

2001-05-07T23:59:59.000Z

230

Studying Dark Energy with Galaxy Cluster Surveys  

E-Print Network [OSTI]

Galaxy cluster surveys provide a powerful means of studying the density and nature of the dark energy. The redshift distribution of detected clusters in a deep, large solid angle SZE or X-ray survey is highly sensitive to the dark energy equation of state. Accurate constraints at the 5% level on the dark energy equation of state require that systematic biases in the mass estimators must be controlled at better than the ~10% level. Observed regularity in the cluster population and the availability of multiple, independent mass estimators suggests these precise measurements are possible. Using hydrodynamical simulations that include preheating, we show that the level of preheating required to explain local galaxy cluster structure has a dramatic effect on X-ray cluster surveys, but only a mild effect on SZE surveys. This suggests that SZE surveys may be optimal for cosmology while X-ray surveys are well suited for studies of the thermal history of the intracluster medium.

Joseph J. Mohr; Brian OShea; August E. Evrard; John Bialek; Zoltan Haiman

2002-08-05T23:59:59.000Z

231

PDSF, NERSC's Physics Computing Cluster  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

PDSF PDSF PDSF PDSF is a networked distributed computing cluster designed primarily to meet the detector simulation and data analysis requirements of physics, astrophysics and nuclear science collaborations. For more details see About PDSF. Click on the graphs below to see larger versions and longer term graphs. Running Jobs Pending Jobs 24 hour rolling usage graph Rolling 24 Pending Jobs by Group About Find out more about PDSF, including a general overview, and information about research groups and staff... Read More » PDSF Login Node Status Getting Started Guidance on obtaining a new user account, access, passwords, and setup files... Read More » Hardware Configuration Provides guidance on hardware configurations, including: login, compute, grid and transfer nodes, and working with particular file systems.

232

Growth mechanism of hydrogen clusters  

SciTech Connect (OSTI)

It is demonstrated that the exposure of polycrystalline silicon (poly-Si) to monatomic hydrogen results in the formation of H clusters. These H stabilized platelets appear in the near-surface region (100 nm) and are predominantly oriented along {l_brace}111{r_brace} crystallographic planes. Platelet concentrations of {approx}5 x 10{sup 15}, 1.5 x 10{sup 16} -cm{sup {minus}3}, and 2.4 x 10{sup 17} cm{sup {minus}3} were observed in nominally undoped poly-Si, phosphorous doped poly-Si (P = 10{sup 17} cm{sup {minus}3}), and phosphorous doped single crystal silicon (P > 3 x 10{sup 18} cm{sup {minus}3}), respectively. Results obtained on doped c-Si demonstrate that platelet generation occurs only at Fermi-level positions of E{sub C} - E{sub F} < 0.4 eV.

Nickel, N.H.; Anderson, G.B.; Johnson, N.M.; Walker, J.

1997-07-01T23:59:59.000Z

233

High performance computing: Clusters, constellations, MPPs, and future directions  

E-Print Network [OSTI]

and Jim Gray, “High Performance Computing: Crays, Clusters,The Marketplace of High-Performance Computing”, ParallelHigh Performance Computing Clusters, Constellations, MPPs,

Dongarra, Jack; Sterling, Thomas; Simon, Horst; Strohmaier, Erich

2003-01-01T23:59:59.000Z

234

Irradiation-induced defect clustering and amorphization in silicon...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Irradiation-induced defect clustering and amorphization in silicon carbide. Irradiation-induced defect clustering and amorphization in silicon carbide. Abstract: Previous computer...

235

Cryogenic CO2 Formation on Oxidized Gold Clusters Synthesized...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Cryogenic CO2 Formation on Oxidized Gold Clusters Synthesized via Reactive Layer Assisted Deposition. Cryogenic CO2 Formation on Oxidized Gold Clusters Synthesized via Reactive...

236

Three-dimensional Modeling of Fracture Clusters in Geothermal...  

Broader source: Energy.gov (indexed) [DOE]

Three-dimensional Modeling of Fracture Clusters in Geothermal Reservoirs; 2010 Geothermal Technology Program Peer Review Report Three-dimensional Modeling of Fracture Clusters in...

237

Optimization of the Coupled Cluster Implementation in NWChem...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Optimization of the Coupled Cluster Implementation in NWChem on Petascale Parallel Architectures. Optimization of the Coupled Cluster Implementation in NWChem on Petascale Parallel...

238

Are Cluster Ion Analysis Beams Good Choices for Hydrogen Depth...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Cluster Ion Analysis Beams Good Choices for Hydrogen Depth Profiling Using Time-of-Flight Secondary Ion Mass Spectrometry? Are Cluster Ion Analysis Beams Good Choices for Hydrogen...

239

First Results on Shear-selected Clusters from the Deep Lens Survey: Optical Imaging, Spectroscopy, and X-Ray Follow-up  

Science Journals Connector (OSTI)

We present the first sample of galaxy clusters selected on the basis of their weak gravitational lensing shear. The shear induced by a cluster is a function of its mass profile and its redshift relative to the background galaxies being sheared; in contrast to more traditional methods of selecting clusters, shear selection does not depend on the cluster's star formation history, baryon content, or dynamical state. Because mass is the property of clusters that provides constraints on cosmological parameters, the dependence on these other parameters could induce potentially important biases in traditionally selected samples. Comparison of a shear-selected sample with optically and X-ray-selected samples is therefore of great importance. Here we present the first step toward a new shear-selected sample: the selection of cluster candidates from the first 8.6 deg2 of the 20 deg2 Deep Lens Survey (DLS), and tabulation of their basic properties such as redshifts and optical and X-ray counterparts.

D. Wittman; I. P. Dell'Antonio; J. P. Hughes; V. E. Margoniner; J. A. Tyson; J. G. Cohen; D. Norman

2006-01-01T23:59:59.000Z

240

The Group Evolution Multiwavelength Study (GEMS): the Sample and Datasets  

E-Print Network [OSTI]

Galaxy groups have been under-studied relative to their richer counterparts -- clusters. The Group Evolution Multiwavelength Study (GEMS) aims to redress some the balance. Here we describe the GEMS sample selection and resulting sample of 60 nearby (distance dataset of X-ray, optical and HI imaging. ROSAT X-ray images of each group are presented. GEMS also utilizes near-infrared imaging from the 2MASS survey and optical spectra from the 6dFGS. These observational data are complemented by mock group catalogues generated from the latest LCDM simulations with gas physics included. Existing GEMS publications are briefly highlighted as are future publication plans.

Duncan A. Forbes; Trevor Ponman; Frazer Pearce; John Osmond; Virginia Kilborn; Sarah Brough; Somak Raychaudhury; Carole Mundell; Trevor Miles; Katie Kern

2006-02-09T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

September 2004 Water Sampling  

Office of Legacy Management (LM)

3-Sampling and Analysis Work Orders Attachment 4-Trip Reports DVP-June and September 2013, Durango, Colorado U.S. Department of Energy RIN 13055370 and 13085577 March 2014 Page...

242

September 2004 Water Sampling  

Office of Legacy Management (LM)

agency thereof or its contractors or subcontractors. U.S. Department of Energy DVP-May 2013, Rulison, Colorado October 2013 RIN 13055300 Page i Contents Sampling Event Summary...

243

September 2004 Water Sampling  

Office of Legacy Management (LM)

analyses were conducted as specified in the 2004 Monticello Mill Tailings Site Operable Unit III Post-Record of Decision Monitoring Plan, Draft Final and Sampling and Analysis Plan...

244

September 2004 Water Sampling  

Office of Legacy Management (LM)

2014 Groundwater, Surface Water, Produced Water, and Natural Gas Sampling at the Gasbuggy, New Mexico, Site October 2014 LMSGSBS00614 Available for sale to the public from: U.S....

245

September 2004 Water Sampling  

Office of Legacy Management (LM)

Site August 2014 LMSGRNS00614 This page intentionally left blank U.S. Department of Energy DVP-June 2014, Green River, Utah August 2014 RIN 14066228 Page i Contents Sampling...

246

Climatic data, sample of  

Science Journals Connector (OSTI)

The representative sample data given below is derived from Climates of the World (Environmental Data Service, 1972). To facilitate conversion from degrees Fahrenheit, inches of precipitation, and elevation in fee...

John E. Oliver

1987-01-01T23:59:59.000Z

247

Characterization of clusters in rapid granular flows  

Science Journals Connector (OSTI)

The clustering phenomenon within two-dimensional, rapid granular, simple shear flows is investigated. Two characterizations are developed and implemented for monodisperse systems, revealing physically meaningful insight. First, a new feature of the radial distribution function is identified for these dissipative granular systems, which is not present in molecular (nondissipative) systems. Namely, a long-scale minimum occurs at a distance representing the average distance between the center of a cluster and the center of a dilute region. Results indicate that center-to-center distances are least (i.e., clusters are most tightly packed) for systems of moderate particle concentrations and low restitution coefficients. In addition, concentration and temperature measurements of clustered and dilute regions are also obtained using a Gaussian filter that is based on this center-to-center distance and, thus, provides a means of appropriately defining local concentrations. These results confirm previous findings that cluster prevalence increases with decreasing dissipation and that clustered regions have lower temperatures than their dilute counterparts. Surprisingly, however, the results indicate that cluster prevalence, defined by normalized concentration differences between the two regions, decrease monotonically with an increase in overall particle concentration.

R. Brent Rice and Christine M. Hrenya

2009-02-11T23:59:59.000Z

248

Effects of $?$-cluster breaking on 3$?$ cluster structures in $^{12}$C  

E-Print Network [OSTI]

To clarify the effects of $\\alpha$-cluster breaking on 3$\\alpha$ cluster structures in $^{12}$C, we investigate $^{12}$C using a hybrid model that combines the Brink-Bloch cluster model with the $p_{3/2}$ subshell closure wave function. We have found that $\\alpha$-cluster breaking caused by spin-orbit force significantly changes cluster structures of excited $0^{+}$ states through orthogonality to lower states. Spatially developed cluster components of the $0^{+}_{2}$ state are reduced. The $0^{+}_{3}$ state changes from a vibration mode in the bending motion of three $\\alpha$ clusters to a chain-like 3$\\alpha$ structure having an open triangle configuration. As a result of these structure changes of $0^{+}$ states, the band assignment for the $2^{+}_{2}$ state is changed by the $\\alpha$-cluster breaking effect. Namely, in model calculations without the $\\alpha$-cluster breaking effect, the $0^{+}_{2}$ state is assigned to be the band-head of the $2^{+}_{2}$ state. However, when we incorporate $\\alpha$-cluster breaking caused by the spin-orbit force, the $0^{+}_{3}$ state is regarded as the band-head of the $2^{+}_{2}$ state.

Tadahiro Suhara; Yoshiko Kanada-En'yo

2014-11-05T23:59:59.000Z

249

Dissolution actuated sample container  

DOE Patents [OSTI]

A sample collection vial and process of using a vial is provided. The sample collection vial has an opening secured by a dissolvable plug. When dissolved, liquids may enter into the interior of the collection vial passing along one or more edges of a dissolvable blocking member. As the blocking member is dissolved, a spring actuated closure is directed towards the opening of the vial which, when engaged, secures the vial contents against loss or contamination.

Nance, Thomas A.; McCoy, Frank T.

2013-03-26T23:59:59.000Z

250

IceCube search for dark matter annihilation in nearby galaxies and galaxy clusters  

Science Journals Connector (OSTI)

We present the results of a first search for self-annihilating dark matter in nearby galaxies and galaxy clusters using a sample of high-energy neutrinos acquired in 339.8 days of live time during 2009/10 with the IceCube neutrino observatory in its 59-string configuration. The targets of interest include the Virgo and Coma galaxy clusters, the Andromeda galaxy, and several dwarf galaxies. We obtain upper limits on the cross section as a function of the weakly interacting massive particle mass between 300 GeV and 100 TeV for the annihilation into bbŻ, W+W-, ?+?-, ?+?-, and ??Ż. A limit derived for the Virgo cluster, when assuming a large effect from subhalos, challenges the weakly interacting massive particle interpretation of a recently observed GeV positron excess in cosmic rays.

M. G. Aartsen et al. (IceCube Collaboration)

2013-12-06T23:59:59.000Z

251

Liquid sampling system  

DOE Patents [OSTI]

A conduit extends from a reservoir through a sampling station and back to the reservoir in a closed loop. A jet ejector in the conduit establishes suction for withdrawing liquid from the reservoir. The conduit has a self-healing septum therein upstream of the jet ejector for receiving one end of a double-ended cannula, the other end of which is received in a serum bottle for sample collection. Gas is introduced into the conduit at a gas bleed between the sample collection bottle and the reservoir. The jet ejector evacuates gas from the conduit and the bottle and aspirates a column of liquid from the reservoir at a high rate. When the withdrawn liquid reaches the jet ejector the rate of flow therethrough reduces substantially and the gas bleed increases the pressure in the conduit for driving liquid into the sample bottle, the gas bleed forming a column of gas behind the withdrawn liquid column and interrupting the withdrawal of liquid from the reservoir. In the case of hazardous and toxic liquids, the sample bottle and the jet ejector may be isolated from the reservoir and may be further isolated from a control station containing remote manipulation means for the sample bottle and control valves for the jet ejector and gas bleed. 5 figs.

Larson, L.L.

1984-09-17T23:59:59.000Z

252

Liquid sampling system  

DOE Patents [OSTI]

A conduit extends from a reservoir through a sampling station and back to the reservoir in a closed loop. A jet ejector in the conduit establishes suction for withdrawing liquid from the reservoir. The conduit has a self-healing septum therein upstream of the jet ejector for receiving one end of a double-ended cannula, the other end of which is received in a serum bottle for sample collection. Gas is introduced into the conduit at a gas bleed between the sample collection bottle and the reservoir. The jet ejector evacuates gas from the conduit and the bottle and aspirates a column of liquid from the reservoir at a high rate. When the withdrawn liquid reaches the jet ejector the rate of flow therethrough reduces substantially and the gas bleed increases the pressure in the conduit for driving liquid into the sample bottle, the gas bleed forming a column of gas behind the withdrawn liquid column and interrupting the withdrawal of liquid from the reservoir. In the case of hazardous and toxic liquids, the sample bottle and the jet ejector may be isolated from the reservoir and may be further isolated from a control station containing remote manipulation means for the sample bottle and control valves for the jet ejector and gas bleed.

Larson, Loren L. (Idaho Falls, ID)

1987-01-01T23:59:59.000Z

253

The 2dF Galaxy Redshift Survey: The dependence of galaxy clustering on luminosity and spectral type  

E-Print Network [OSTI]

We investigate the dependence of galaxy clustering on luminosity and spectral type using the 2dF Galaxy Redshift Survey (2dFGRS). Spectral types are assigned using the principal component analysis of Madgwick et al. We divide the sample into two broad spectral classes: galaxies with strong emission lines (`late-types'), and more quiescent galaxies (`early-types'). We measure the clustering in real space, free from any distortion of the clustering pattern due to peculiar velocities, for a series of volume-limited samples. The projected correlation functions of both spectral types are well described by a power law for transverse separations in the range 2 < (sigma/Mpc/h) < 15, with a marginally steeper slope for early-types than late-types. Both early and late types have approximately the same dependence of clustering strength on luminosity, with the clustering amplitude increasing by a factor of ~2.5 between L* and 4 L*. At all luminosities, however, the correlation function amplitude for the early-types is ~50% higher than that of the late-types. These results support the view that luminosity, and not type, is the dominant factor in determining how the clustering strength of the whole galaxy population varies with luminosity.

P. Norberg; C. M. Baugh; E. Hawkins; S. Maddox; D. Madgwick; O. Lahav; S. Cole; C. S. Frenk; I. Baldry; J. Bland-Hawthorn; T. Bridges; R. Cannon; M. Colless; C. Collins; W. Couch; G. Dalton; S. P. Driver; G. Efstathiou; R. S. Ellis; K. Glazebrook; C. Jackson; I. Lewis; S. Lumsden; J. A. Peacock; B. A. Peterson; W. Sutherland; K. Taylor; the 2dFGRS Team

2002-01-24T23:59:59.000Z

254

X-ray Spectroscopy of Cooling Cluster  

SciTech Connect (OSTI)

We review the X-ray spectra of the cores of clusters of galaxies. Recent high resolution X-ray spectroscopic observations have demonstrated a severe deficit of emission at the lowest X-ray temperatures as compared to that expected from simple radiative cooling models. The same observations have provided compelling evidence that the gas in the cores is cooling below half the maximum temperature. We review these results, discuss physical models of cooling clusters, and describe the X-ray instrumentation and analysis techniques used to make these observations. We discuss several viable mechanisms designed to cancel or distort the expected process of X-ray cluster cooling.

Peterson, J.R.; /SLAC; Fabian, A.C.; /Cambridge U., Inst. of Astron.

2006-01-17T23:59:59.000Z

255

Online Spectral Clustering on Network Streams  

E-Print Network [OSTI]

.3.1 First Order Approximation (FOA) Approach . . . . . . . . . . . . . 109 7.3.2 Eigen Perturbation Theory Based Approaches . . . . . . . . . . . . . 111 7.3.2.1 General Eigen Perturbation Theory (GEPT) Approach . . . 111 7.3.2.2 Enhanced Eigen Perturbation... of an evolving graph with two snapshots . . . . . . . . . . . . . 109 7.2 The clustering results of the evolving graph in Figure 7.1 by using SC-FOA . 110 xi 7.3 The clustering results of the evolving graph in Figure 7.1 by using FOA . . . 111 7.4 The clustering...

Jia, Yi

2012-12-31T23:59:59.000Z

256

X-ray Spectroscopy of Cooling Clusters  

E-Print Network [OSTI]

We review the X-ray spectra of the cores of clusters of galaxies. Recent high resolution X-ray spectroscopic observations have demonstrated a severe deficit of emission at the lowest X-ray temperatures as compared to that expected from simple radiative cooling models. The same observations have provided compelling evidence that the gas in the cores is cooling below half the maximum temperature. We review these results, discuss physical models of cooling clusters, and describe the X-ray instrumentation and analysis techniques used to make these observations. We discuss several viable mechanisms designed to cancel or distort the expected process of X-ray cluster cooling.

J. R. Peterson; A. C. Fabian

2005-12-21T23:59:59.000Z

257

The 2dF Galaxy Redshift Survey: Luminosity dependence of galaxy clustering  

E-Print Network [OSTI]

We investigate the dependence of the strength of galaxy clustering on intrinsic luminosity using the Anglo-Australian two degree field galaxy redshift survey (2dFGRS). The 2dFGRS is over an order of magnitude larger than previous redshift surveys used to address this issue. We measure the projected two-point correlation function of galaxies in a series of volume-limited samples. The projected correlation function is free from any distortion of the clustering pattern induced by peculiar motions and is well described by a power-law in pair separation over the range 0.1 < r /h Mpc < 10. The clustering of L* galaxies in real space is well fit by a correlation length r0 = 4.9 +/- 0.3 /h Mpc and power-law slope gamma = 1.71 +/- 0.06. The clustering amplitude increases slowly with absolute magnitude for galaxies fainter than M*, but rises more strongly at higher luminosities. At low luminosities, our results agree with measurements from the SSRS2 by Benoist et al. However, we find a weaker dependence of clustering strength on luminosity at the highest luminosities. The correlation function amplitude increases by a factor of 4.0 between $M_{b_{J}} -5\\log_{10}h = -18$ and -22.5, and the most luminous galaxies are 3.0 times more strongly clustered than L* galaxies. The power-law slope of the correlation function shows remarkably little variation for samples spanning a factor of 20 in luminosity. Our measurements are in very good agreement with the predictions of the hierarchical galaxy formation models of Benson et al.

P. Norberg; C. M. Baugh; E. Hawkins; S. Maddox; J. A. Peacock; S. Cole; C. S. Frenk; J. Bland-Hawthorn; T. Bridges; R. Cannon; M. Colless; C. Collins; W. Couch; G. Dalton; S. P. Driver; G. Efstathiou; R. S. Ellis; K. Glazebrook; C. Jackson; O. Lahav; I. Lewis; S. Lumsden; B. A. Peterson; W. Sutherland; K. Taylor; the 2dFGRS Team

2001-10-19T23:59:59.000Z

258

The 2dF Galaxy Redshift Survey: correlation with the ROSAT-ESO Flux Limited X-ray (REFLEX) galaxy cluster survey  

E-Print Network [OSTI]

The ROSAT-ESO Flux Limited X-ray (REFLEX) galaxy cluster survey and the 2dF Galaxy Redshift Survey (2dFGRS) respectively comprise the largest, homogeneous X-ray selected cluster catalogue and completed galaxy redshift survey. In this work we combine these two outstanding datasets in order to study the effect of the large-scale cluster environment, as traced by X-ray luminosity, on the properties of the cluster member galaxies. We measure the LX-sigma relation from the correlated dataset and find it to be consistent with recent results found in the literature. Using a sample of 19 clusters with LX>=0.36*10^44 erg s^-1 in the (0.1-2.4 keV) band, and 49 clusters with lower X-ray luminosity, we find that the fraction of early spectral type (eta<=-1.4), passively-evolving galaxies is significantly higher in the high-LX sample within R200. We extend the investigation to include composite bJ cluster luminosity functions, and find that the characteristic magnitude of the Schechter-function fit to the early-type luminosity function is fainter for the high-LX sample compared to the low-LX sample (Delta M*=0.58+/-0.14). This seems to be driven by a deficit of such galaxies with M_bJ ~ -21. In contrast, we find no significant differences between the luminosity functions of star-forming, late-type galaxies. We believe these results are consistent with a scenario in which the high-LX clusters are more dynamically evolved systems than the low-LX clusters.

Matt Hilton; Chris Collins; Roberto De Propris; Ivan K. Baldry; Carlton M. Baugh; Joss Bland-Hawthorn; Terry Bridges; Russell Cannon; Shaun Cole; Matthew Colless; Warrick J. Couch; Gavin B. Dalton; Simon P. Driver; George Efstathiou; Richard S. Ellis; Carlos S. Frenk; Karl Glazebrook; Carole A. Jackson; Ofer Lahav; Ian Lewis; Stuart Lumsden; Steve J. Maddox; Darren Madgwick; Peder Norberg; John A. Peacock; Bruce A. Peterson; Will Sutherland; Keith Taylor

2005-08-09T23:59:59.000Z

259

Molecular-like Ag clusters sensitized near-infrared down-conversion luminescence in oxyfluoride glasses for broadband spectral modification  

SciTech Connect (OSTI)

Molecular-like Ag clusters sized at 1–4 nm have been stabilized in Pb/Cd-free oxyfluoride glasses, showing broadband excitation/emission characteristics and unique wavelength-dependent luminescent performance with a maximal quantum yield of 26.9%. It was experimentally demonstrated that an energy transfer route of Ag clusters ? Tb{sup 3+} ? Yb{sup 3+} occurs in Ag{sup +}/Tb{sup 3+}/Yb{sup 3+} tri-doped sample, wherein Ag clusters act as sensitizers for near-infrared down-conversion spectral modification. Hopefully, the proposed strategy that noble metal clusters being applied for harvesting solar radiation may potentially solve the sticky problems of the narrow excitation bandwidth and the low excitation efficiency in rare earth ions doped down-conversion materials.

Lin, Hang; Chen, Daqin; Yu, Yunlong; Zhang, Rui; Wang, Yuansheng [State Key Lab of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China)] [State Key Lab of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China)

2013-08-26T23:59:59.000Z

260

Constraining globular cluster formation through studies of young massive clusters - V. ALMA observations of clusters in the Antennae  

E-Print Network [OSTI]

Some formation scenarios that have been put forward to explain multiple populations within Globular Clusters (GCs) require that the young massive cluster have large reservoirs of cold gas within them, which is necessary to form future generations of stars. In this paper we use deep observations taken with Atacama Large Millimeter/sub-millimeter Array (ALMA) to assess the amount of molecular gas within 3 young (50-200 Myr) massive (~10^6 Msun) clusters in the Antennae galaxies. No significant CO(3--2) emission was found associated with any of the three clusters. We place upper limits for the molecular gas within these clusters of ~1x10^5 Msun (or <9 % of the current stellar mass). We briefly review different scenarios that propose multiple episodes of star formation and discuss some of their assumptions and implications. Our results are in tension with the predictions of GC formation scenarios that expect large reservoirs of cool gas within young massive clusters at these ages.

Cabrera-Ziri, I; Longmore, S N; Brogan, C; Hollyhead, K; Larsen, S S; Whitmore, B; Johnson, K; Chandar, R; Henshaw, J D; Davies, B; Hibbard, J E

2015-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Cluster size effects on sintering, CO adsorption, and implantation in Ir/SiO{sub 2}  

SciTech Connect (OSTI)

A series of planar model catalysts have been prepared via deposition of Ir{sub n}{sup +} on thermally grown amorphous SiO{sub 2}/Si(100) and ion scattering spectroscopy was used to probe surface structure as a function of cluster size, impact energy, and surface temperature. Deposition of Ir{sub 2} or Ir{sub 10} at low energies and room temperature results in stable clusters forming one- or two-dimensional single layer islands on the oxide surface. Heating the samples to 750 K leads to agglomeration, forming multilayer structures on the surface. Ir{sub 1} deposited under similar conditions sinters into large clusters at room temperature. Deposition at 110 K at least partially stabilizes the Ir atoms with respect to diffusion and sintering. At higher deposition energies, partial implantation into the surface is observed, but this appears to be insufficient to stabilize the clusters against sintering at elevated temperature. At low temperatures, substrate-mediated adsorption of CO is found to be highly efficient, leading to near saturation coverages of CO bound atop the Ir{sub n} clusters. The CO can be removed by careful He{sup +} sputtering. The deposition/binding behavior of Ir{sub n} on SiO{sub 2} is quite different from Ir{sub n}/TiO{sub 2}(110), for which the clusters bind in three-dimensional morphology, starting at Ir{sub 5}. That system also shows substrate-mediated adsorption of CO, but the CO preferentially binds at the periphery of the clusters rather than on top.

Kaden, W. E.; Kunkel, W. A.; Anderson, Scott L. [Department of Chemistry, University of Utah, 315 S. 1400 E. RM 2020, Salt Lake City, Utah 84112-0850 (United States)

2009-09-21T23:59:59.000Z

262

The Globular Cluster Systems in the Coma Ellipticals. IV: WFPC2 Photometry for Five Giant Ellipticals  

E-Print Network [OSTI]

We analyze photometric data in V and I for the globular cluster (GC) systems in five of the giant ellipticals in the Coma Cluster: NGC 4874, 4881, 4889, 4926, and IC 4051. We find that the GC luminosity functions are quite similar to one another, with a turnover derived from a composite sample of more than 9,000 GCs at V = 27.71 +- 0.07 (M_V = -7.3). Both a simple Gaussian curve and an evolved Schechter function fit the bright half of the GCLF equally well, though the Coma GCLF is broader and has a higher ``cutoff mass'' (M_c ~ 3 x 10^6 M_Sun) than in any of the Virgo giants. These five Coma members exhibit a huge range in GC specific frequency, from a low of S_N = 0.7 for NGC 4881 up to 12 for IC 4051 and NGC 4874. No single formation scenario appears able to account for these differences in otherwise-similar galaxies. The supergiant NGC 4874 has the richest globular cluster system known, probably holding more than 30,000 clusters; its true extent is not yet determined and may extend well out into the Coma potential well. For the three biggest GC systems (NGC 4874, 4889, IC 4051), all three populations are dominated by red, metal-rich clusters. Their metallicity distributions also may all have the normal bimodal form, with the two sequences at the expected mean colors (blue) = 0.98 and (red) = 1.15. However, the color distributions and relative numbers of metal-rich clusters show intriguing counterexamples to a trend established by Peng et al. 2008 (ApJ 681, 197) for the Virgo galaxies. At the very highest-density and most massive regimes represented by the Coma supergiants, formation of metal-rich clusters seems to have been especially favored.

W. E. Harris; J. J. Kavelaars; D. A. Hanes; C. J. Pritchet; W. A. Baum

2008-11-10T23:59:59.000Z

263

The APM cluster-galaxy cross-correlation function : Constraints on Omega and galaxy bias  

E-Print Network [OSTI]

(abridged) We estimate the cluster-galaxy cross-correlation function (Xi_cg), from the APM galaxy and galaxy cluster surveys, both in real space from the inversion of projected statistics and in redshift space using the galaxy and cluster redshift samples. The amplitude of Xi_cg is found to be almost independent of cluster richness. At large separations, r >~5 h^-1 Mpc, Xi_cg has a similar shape to the galaxy-galaxy and cluster-cluster autocorrelation functions. Xi_cg in redshift space can be related to the real space Xi_cg by convolution with an appropriate velocity field model. Here we apply a spherical collapse model, which we have tested against N-body simulations, finding that it provides a surprisingly accurate description of the averaged infall velocity of matter into galaxy clusters. We use this model to estimate beta (Omega^{0.6}/b) and find that it tends to overestimate the true result in simulations by only ~10-30%. Application to the APM results yields beta=0.43 with beta < 0.87 at 95% confidence. We also compare the APM Xi_cg and galaxy autocorrelations to results from popular cosmological models and derive two independent estimates of the galaxy biasing expected as a function of scale. Both low and critical density CDM models require anti-biasing by a factor ~2 on scales r <~ 2 h^-1Mpc and an MDM model is consistent with a constant biasing factor on all scales. We use the velocity fields predicted from the different models to distort the APM real space cross-correlation function. Comparison with the APM redshift space Xi_cg yields an estimate of the value of Omega^0.6 needed in each model. Only the low Omega model is fully consistent with observations, with MDM marginally excluded at the ~2 sigma level.

Rupert Croft; Gavin Dalton; George Efstathiou

1998-01-27T23:59:59.000Z

264

Fluid sampling system  

DOE Patents [OSTI]

An fluid sampling system allows sampling of radioactive liquid without spillage. A feed tank is connected to a liquid transfer jet powered by a pumping chamber pressurized by compressed air. The liquid is pumped upwardly into a sampling jet of a venturi design having a lumen with an inlet, an outlet, a constricted middle portion, and a port located above the constricted middle portion. The liquid is passed under pressure through the constricted portion causing its velocity to increase and its pressure to be decreased, thereby preventing liquid from escaping. A septum sealing the port can be pierced by a two pointed hollow needle leading into a sample bottle also sealed by a pierceable septum affixed to one end. The bottle is evacuated by flow through the sample jet, cyclic variation in the sampler jet pressure periodically leaves the evacuated bottle with lower pressure than that of the port, thus causing solution to pass into the bottle. The remaining solution in the system is returned to the feed tank via a holding tank. 4 figs.

Houck, E.D.

1994-10-11T23:59:59.000Z

265

Radial Alignment in Simulated Clusters  

E-Print Network [OSTI]

Observational evidence for the radial alignment of satellites with their dark matter host has been accumulating steadily in the past few years. The effect is seen over a wide range of scales, from massive clusters of galaxies down to galaxy-sized systems, yet the underlying physical mechanism has still not been established. To this end, we have carried out a detailed analysis of the shapes and orientations of dark matter substructures in high-resolution N-body cosmological simulations. We find a strong tendency for radial alignment of the substructure with its host halo: the distribution of halo major axes is very anisotropic, with the majority pointing towards the center of mass of the host. The alignment peaks once the sub-halo has passed the virial radius of the host for the first time, but is not subsequently diluted, even after the halos have gone through as many as four pericentric passages. This evidence points to the existence of a very rapid dynamical mechanism acting on these systems and we argue that tidal torquing throughout their orbits is the most likely candidate.

Maria J. Pereira; Greg L. Bryan; Stuart P. D. Gill

2008-01-23T23:59:59.000Z

266

Spectral Energy Distributions and Masses of 304 M31 Old Star Clusters  

E-Print Network [OSTI]

This paper presents CCD multicolor photometry for 304 old star clusters in the nearby spiral galaxy M31. Of which photometry of 55 star clusters is first obtained. The observations were carried out as a part of the Beijing--Arizona--Taiwan--Connecticut (BATC) Multicolor Sky Survey from 1995 February to 2008 March, using 15 intermediate-band filters covering 3000--10000 \\AA. Detailed comparisons show that our photometry is in agreement with previous measurements. Based on the ages and metallicities from Caldwell et al. and the photometric measurements here, we estimated the clusters' masses by comparing their multicolor photometry with stellar population synthesis models. The results show that the sample clusters have masses between $\\sim 3\\times10^4 M_\\odot$ and $\\sim 10^7 M_\\odot$ with the peak of $\\sim 4\\times10^5 M_\\odot$. The masses here are in good agreement with those in previous studies. Combined with the masses of young star clusters of M31 from Wang et al., we find that the peak of mass of old cluste...

Ma, Jun; Wu, Zhenyu; Zhang, Tianmeng; Zou, Hu; Nie, Jundan; Zhou, Zhiming; Zhou, Xu; Wu, Jianghua; Du, Cuihua; Yuan, Qirong

2014-01-01T23:59:59.000Z

267

Variance, Skewness & Kurtosis: results from the APM Cluster Redshift Survey and model predictions  

E-Print Network [OSTI]

We estimate the variance $\\xibar_2$, the skewness $\\xibar_3$ and the kurtosis $\\xibar_4$ in the distribution of density fluctuations in a complete sample from the APM Cluster Redshift Survey with 339 clusters and a mean depth $ \\sim 250\\Mpc$. We are able to measure the statistics of fluctuations in spheres of radius $R \\simeq 5-80 \\Mpc$, with reasonable errorbars. The statistics in the cluster distribution follow the hierarchical pattern $\\xibar_J=S_J~\\xibar_2^{J-1}$ with $S_J$ roughly constant, $S_3 \\simeq 2$ and $S_4 \\sim 8$. We analyse the distribution of clusters taken from N-body simulations of different dark matter models. The results are compared with an alternative method of simulating clusters which uses the truncated Zel'dovich approximation. We argue that this alternative method is not reliable enough for making quantitative predictions of $\\xibar$. The N-body simulation results follow similar hierarchical relations to the observations, with $S_J$ almost unaffected by redshift distortions from peculiar motions. The standard $\\Omega=1$ Cold Dark Matter (CDM) model is inconsistent with either the second, third or fourth order statistics at all scales. However both a hybrid Mixed Dark Matter model and a low density CDM variant agree with the $\\xibar_J$ observations.

Enrique Gaztańaga; Rupert Croft; Gavin Dalton

1995-01-31T23:59:59.000Z

268

Environmental Business Cluster | Open Energy Information  

Open Energy Info (EERE)

Business Cluster Business Cluster Jump to: navigation, search Logo: Environmental Business Cluster Name Environmental Business Cluster Address 2 North First Street, Third Floor Place San Jose, California Zip 95112 Region Bay Area Coordinates 37.3456227°, -121.8847222° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":37.3456227,"lon":-121.8847222,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

269

Spectral Synthesis of Massive Stars in Clusters  

E-Print Network [OSTI]

Stellar clusters are thought to be the simplest stellar systems and the closest observational counterparts to theoretical models for single stellar populations. Progress in our understanding of the atmospheres and evolution of massive stars has led to generally reliable synthesis models. The future release of new evolution models with rotation, however, will require non-trivial updates to previously published synthesis models, in particular for all Wolf-Rayet and red supergiant related quantities. Cluster synthesis work is currently progressing from a purely stellar approach to a more comprehensive stellar+cluster perspective. The photometric evolution of stars and the dynamical evolution of clusters are delicately interwoven. Recent work attempts to combine these seemingly related fields.

Claus Leitherer

2006-08-31T23:59:59.000Z

270

1 Globular Cluster Systems William E. Harris  

E-Print Network [OSTI]

1 Globular Cluster Systems William E. Harris Department of Physics & Astronomy, McMaster University; 2 W. E. Harris 7. The GCLF is evaluated as a standard candle for distance determination. For giant E

Harris, William E.

271

UCD Candidates in the Hydra Cluster  

E-Print Network [OSTI]

NGC 3311, the giant cD galaxy in the Hydra cluster (A1060), has one of the largest globular cluster systems known. We describe new Gemini GMOS (g',i') photometry of the NGC 3311 field which reveals that the red, metal-rich side of its globular cluster population extends smoothly upward into the mass range associated with the new class of Ultra-Compact Dwarfs (UCDs). We identify 29 UCD candidates with estimated masses > 6x10^6 solar masses and discuss their characteristics. This UCD-like sequence is the most well defined one yet seen, and reinforces current ideas that the high-mass end of the globular cluster sequence merges continuously into the UCD sequence, which connects in turn to the E galaxy structural sequence.

Elizabeth Wehner; William Harris

2007-08-10T23:59:59.000Z

272

Flagship Cluster Hiring Initiative Computational Science  

E-Print Network [OSTI]

Flagship Cluster Hiring Initiative Computational Science: Advancing Research, Society and the Economy Gabrielle Allen (PI) Thomas Sterling (Presenter/co-PI) Department of Computer Science Center for Computation & Technology #12;Computational Science: Advancing Research, Society and the Economy, External

Allen, Gabrielle

273

JLab Cluster Tops 100 Teraflops | Jefferson Lab  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

JLab Cluster Tops 100 Teraflops NEWPORT NEWS, VA, Oct. 14 - The fastest computer system in Hampton Roads has booted up with more than 100 Teraflops of processing power. Located at...

274

Diffusion stability of bubbles in a cluster  

Science Journals Connector (OSTI)

The diffusion stability of gas bubbles in one-fraction and two-fraction clusters ... gas concentrations in the liquid at which the bubble tends to one of two equilibrium states because of diffusion processes betw...

É. Sh. Nasibullaeva; I. Sh. Akhatov

2007-07-01T23:59:59.000Z

275

Gravitational clustering in Static and Expanding Backgrounds  

E-Print Network [OSTI]

A brief summary of several topics in the study of gravitational many body problem is given. The discussion covers both static backgrounds (applicable to astrophysical systems) as well as clustering in an expanding background (relevant for cosmology)

T. Padmanabhan

2003-08-28T23:59:59.000Z

276

Nonthermal emission from clusters of galaxies  

Science Journals Connector (OSTI)

We show that the spectral and radial distribution of the nonthermal emission of massive, M  1014.5M?, galaxy clusters may be approximately described by simple analytic expressions, which depend on the cluster thermal X-ray properties and on two model parameter, ?core and ?e. ?core is the ratio of the cosmic-ray (CR) energy density (within a logarithmic CR energy interval) and the thermal energy density at the cluster core, and ?e(p) is the fraction of the thermal energy generated in strong collisionless shocks, which is deposited in CR electrons (protons). Using a simple analytic model for the evolution of intra-cluster medium CRs, which are produced by accretion shocks, we find that ?core ?p/200, nearly independent of cluster mass and with a scatter ?ln ?core 1 between clusters of given mass. We show that the hard X-ray (HXR) and ?-ray luminosities produced by inverse Compton scattering of CMB photons by electrons accelerated in accretion shocks (primary electrons) exceed the luminosities produced by secondary particles (generated in hadronic interactions within the cluster) by factors 500(?e/?p)(T/10 keV)?1/2 and 150(?e/?p)(T/10 keV)?1/2 respectively, where T is the cluster temperature. Secondary particle emission may dominate at the radio and very high energy ( 1 TeV) ?-ray bands. Our model predicts, in contrast with some earlier work, that the HXR and ?-ray emission from clusters of galaxies are extended, since the emission is dominated at these energies by primary (rather than by secondary) electrons. Our predictions are consistent with the observed nonthermal emission of the Coma cluster for ?p ~ ?e ~ 0.1. The implications of our predictions to future HXR observations (e.g. by NuStar, Simbol-X) and to (space/ground based) ?-ray observations (e.g. by Fermi, HESS, MAGIC, VERITAS) are discussed. In particular, we identify the clusters which are the best candidates for detection in ?-rays. Finally, we show that our model's results agree with results of detailed numerical calculations, and that discrepancies between the results of various numerical simulations (and between such results and our model) are due to inaccuracies in the numerical calculations.

Doron Kushnir; Eli Waxman

2009-01-01T23:59:59.000Z

277

Nonthermal emission from clusters of galaxies  

SciTech Connect (OSTI)

We show that the spectral and radial distribution of the nonthermal emission of massive, M ?> 10{sup 14.5}M{sub ?}, galaxy clusters may be approximately described by simple analytic expressions, which depend on the cluster thermal X-ray properties and on two model parameter, ?{sub core} and ?{sub e}. ?{sub core} is the ratio of the cosmic-ray (CR) energy density (within a logarithmic CR energy interval) and the thermal energy density at the cluster core, and ?{sub e(p)} is the fraction of the thermal energy generated in strong collisionless shocks, which is deposited in CR electrons (protons). Using a simple analytic model for the evolution of intra-cluster medium CRs, which are produced by accretion shocks, we find that ?{sub core} ? ?{sub p}/200, nearly independent of cluster mass and with a scatter ?ln ?{sub core} ? 1 between clusters of given mass. We show that the hard X-ray (HXR) and ?-ray luminosities produced by inverse Compton scattering of CMB photons by electrons accelerated in accretion shocks (primary electrons) exceed the luminosities produced by secondary particles (generated in hadronic interactions within the cluster) by factors ? 500(?{sub e}/?{sub p})(T/10 keV){sup ?1/2} and ? 150(?{sub e}/?{sub p})(T/10 keV){sup ?1/2} respectively, where T is the cluster temperature. Secondary particle emission may dominate at the radio and very high energy (?> 1 TeV) ?-ray bands. Our model predicts, in contrast with some earlier work, that the HXR and ?-ray emission from clusters of galaxies are extended, since the emission is dominated at these energies by primary (rather than by secondary) electrons. Our predictions are consistent with the observed nonthermal emission of the Coma cluster for ?{sub p} ? ?{sub e} ? 0.1. The implications of our predictions to future HXR observations (e.g. by NuStar, Simbol-X) and to (space/ground based) ?-ray observations (e.g. by Fermi, HESS, MAGIC, VERITAS) are discussed. In particular, we identify the clusters which are the best candidates for detection in ?-rays. Finally, we show that our model's results agree with results of detailed numerical calculations, and that discrepancies between the results of various numerical simulations (and between such results and our model) are due to inaccuracies in the numerical calculations.

Kushnir, Doron; Waxman, Eli, E-mail: doron.kushnir@weizmann.ac.il, E-mail: eli.waxman@weizmann.ac.il [Physics Faculty, Weizmann Institute of Science, PO Box 26, Rehovot (Israel)

2009-08-01T23:59:59.000Z

278

Theory for optical absorption in small clusters: Dependence on atomic surface structure and cluster size  

Science Journals Connector (OSTI)

We present a theory which permits for the first time a detailed analysis of the dependence of the absorption spectrum on atomic structure and cluster size. Thus, we determine the development of the collective excitations in small clusters and show that their broadening depends sensitively on the atomic structure, in particular at the surface. Results for Hgn+ clusters show that the plasmon energy is close to its jellium value in the case of spherical-like structures, but is in general between ?p/ ?3 and ?p/ ?2 for compact clusters. A particular success of our theory is the identification of the excitations contributing to the absorption peaks.

S. Grabowski, M. E. Garcia, and K. H. Bennemann

1994-06-20T23:59:59.000Z

279

Viscous sludge sample collector  

DOE Patents [OSTI]

A vertical core sample collection system for viscous sludge. A sample tube's upper end has a flange and is attached to a piston. The tube and piston are located in the upper end of a bore in a housing. The bore's lower end leads outside the housing and has an inwardly extending rim. Compressed gas, from a storage cylinder, is quickly introduced into the bore's upper end to rapidly accelerate the piston and tube down the bore. The lower end of the tube has a high sludge entering velocity to obtain a full-length sludge sample without disturbing strata detail. The tube's downward motion is stopped when its upper end flange impacts against the bore's lower end inwardly extending rim.

Beitel, George A [Richland, WA

1983-01-01T23:59:59.000Z

280

Clustering and Inconsistent Information: A Kernelization Approach  

E-Print Network [OSTI]

CLUSTERING AND INCONSISTENT INFORMATION: A KERNELIZATION APPROACH A Dissertation by YIXIN CAO Submitted to the O ce of Graduate Studies of Texas A&M University in partial ful llment of the requirements for the degree of DOCTOR OF PHILOSOPHY... May 2012 Major Subject: Computer Science CLUSTERING AND INCONSISTENT INFORMATION: A KERNELIZATION APPROACH A Dissertation by YIXIN CAO Submitted to the O ce of Graduate Studies of Texas A&M University in partial ful llment of the requirements...

Cao, Yixin

2012-07-16T23:59:59.000Z

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they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Neutrinos and Gamma Rays from Galaxy Clusters  

E-Print Network [OSTI]

The next generation of neutrino and gamma-ray detectors should provide new insights into the creation and propagation of high-energy protons within galaxy clusters, probing both the particle physics of cosmic rays interacting with the background medium and the mechanisms for high-energy particle production within the cluster. In this paper we examine the possible detection of gamma-rays (via the GLAST satellite) and neutrinos (via the ICECUBE and Auger experiments) from the Coma cluster of galaxies, as well as for the gamma-ray bright clusters Abell 85, 1758, and 1914. These three were selected from their possible association with unidentified EGRET sources, so it is not yet entirely certain that their gamma-rays are indeed produced diffusively within the intracluster medium, as opposed to AGNs. It is not obvious why these inconspicuous Abell-clusters should be the first to be seen in gamma-rays, but a possible reason is that all of them show direct evidence of recent or ongoing mergers. Their identification with the EGRET gamma-ray sources is also supported by the close correlation between their radio and (purported) gamma-ray fluxes. Under favorable conditions (including a proton spectral index of 2.5 in the case of Abell 85, and sim 2.3 for Coma, and Abell 1758 and 1914), we expect ICECUBE to make as many as 0.3 neutrino detections per year from the Coma cluster of galaxies, and as many as a few per year from the Abell clusters 85, 1758, and 1914. Also, Auger may detect as many as 2 events per decade at ~ EeV energies from these gamma-ray bright clusters.

Brandon Wolfe; Fulvio Melia; Roland M. Crocker; Raymond R. Volkas

2008-07-04T23:59:59.000Z

282

Contribution of White Dwarfs to Cluster Masses  

E-Print Network [OSTI]

I present a literature search through 31 July 1997 of white dwarfs (WDs) in open and globular clusters. There are 36 single WDs and 5 WDs in binaries known among 13 open clusters, and 340 single WDs and 11 WDs in binaries known among 11 globular clusters. From these data I have calculated WD mass fractions for four open clusters (the Pleiades, NGC 2168, NGC 3532, and the Hyades) and one globular cluster (NGC 6121). I develop a simple model of cluster evolution that incorporates stellar evolution but not dynamical evolution to interpret the WD mass fractions. I augment the results of my simple model with N-body simulations incorporating stellar evolution (Terlevich 1987; de la Feunte Marcos 1996; Vesperini & Heggie 1997). I find that even though these clusters undergo moderate to strong kinematical evolution the WD mass fraction is relatively insensitive to kinematical evolution. By comparing the cluster mass functions to that of the Galactic disk, and incorporating plausibility arguments for the mass function of the Galactic halo, I estimate the WD mass fraction in these two populations. I assume the Galactic disk is ~10 Gyrs old (Winget et al. 1987; Liebert, Dahn, & Monet 1988; Oswalt et al. 1996) and that the Galactic halo is ~12 Gyrs old (Reid 1997b; Gratton et al. 1997; Chaboyer et al. 1998), although the WD mass fraction is insensitive to age in this range. I find that the Galactic halo should contain 8 to 9% (alpha = -2.35) or perhaps as much as 15 to 17% (alpha = -2.0) of its stellar mass in the form of WDs. The Galactic disk WD mass fraction should be 6 to 7% (alpha = -2.35), consistent with the empirical estimates of 3 to 7% (Liebert, Dahn, & Monet 1988; Oswalt et al. 1996). (abridged)

Ted von Hippel

1998-02-14T23:59:59.000Z

283

Accelerating semantic graph databases on commodity clusters  

SciTech Connect (OSTI)

We are developing a full software system for accelerating semantic graph databases on commodity cluster that scales to hundreds of nodes while maintaining constant query throughput. Our framework comprises a SPARQL to C++ compiler, a library of parallel graph methods and a custom multithreaded runtime layer, which provides a Partitioned Global Address Space (PGAS) programming model with fork/join parallelism and automatic load balancing over a commodity clusters. We present preliminary results for the compiler and for the runtime.

Morari, Alessandro; Castellana, Vito G.; Haglin, David J.; Feo, John T.; Weaver, Jesse R.; Tumeo, Antonino; Villa, Oreste

2013-10-06T23:59:59.000Z

284

Diffusive shielding stabilizes bulk nanobubble clusters  

E-Print Network [OSTI]

Using molecular dynamics, we study the nucleation and stability of bulk nanobubble clusters. We study the formation, growth, and final size of bulk nanobubbles. We find that, as long as the bubble-bubble interspacing is small enough, bulk nanobubbles are stable against dissolution. Simple diffusion calculations provide an excellent match with the simulation results, giving insight into the reason for the stability: nanobubbles in a cluster of bulk nanobubbles "protect" each other from diffusion by a shielding effect.

Weijs, Joost H; Lohse, D

2011-01-01T23:59:59.000Z

285

Nested Cluster Algorithm for Frustrated Quantum Antiferromagnets  

E-Print Network [OSTI]

Simulations of frustrated quantum antiferromagnets suffer from a severe sign problem. We solve the ergodicity problem of the loop-cluster algorithm in a natural way and apply a powerful strategy to address the sign problem. For the spin 1/2 Heisenberg antiferromagnet on a kagome and on a frustrated square lattice, a nested cluster algorithm eliminates the sign problem for large systems. The method is applicable to general lattice geometries but limited to moderate temperatures.

M. Nyfeler; F. -J. Jiang; F. Kämpfer; U. -J. Wiese

2008-03-25T23:59:59.000Z

286

Variation of lattice constant and cluster formation in GaAsBi  

SciTech Connect (OSTI)

We investigate the structural properties of GaAsBi layers grown by molecular beam epitaxy on GaAs at substrate temperatures between 220–315 °C. Irrespective of the growth temperature, the structures exhibited similar Bi compositions, and good overall crystal quality as deduced from X-Ray diffraction measurements. After thermal annealing at temperatures as low as 500 °C, the GaAsBi layers grown at the lowest temperatures exhibited a significant reduction of the lattice constant. The lattice variation was significantly larger for Bi-containing samples than for Bi-free low-temperature GaAs samples grown as a reference. Rutherford backscattering spectrometry gave no evidence of Bi diffusing out of the layer during annealing. However, dark-field and Z-contrast transmission electron microscopy analyses revealed the formation of GaAsBi clusters with a Bi content higher than in the surrounding matrix, as well as the presence of metallic As clusters. The apparent reduction of the lattice constant can be explained by a two-fold process: the diffusion of the excess As incorporated within As{sub Ga} antisites to As clusters, and the reduction of the Bi content in the GaAs matrix due to diffusion of Bi to GaAsBi clusters. Diffusion of both As and Bi are believed to be assisted by the native point defects, which are present in the low-temperature as-grown material.

Puustinen, J.; Schramm, A.; Guina, M. [Optoelectronics Research Centre, Tampere University of Technology, P.O. Box 692, FI-33101 Tampere (Finland)] [Optoelectronics Research Centre, Tampere University of Technology, P.O. Box 692, FI-33101 Tampere (Finland); Wu, M.; Luna, E. [Paul-Drude Institut für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin (Germany)] [Paul-Drude Institut für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin (Germany); Laukkanen, P. [Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland)] [Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland); Laitinen, M.; Sajavaara, T. [Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä (Finland)] [Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä (Finland)

2013-12-28T23:59:59.000Z

287

DISENTANGLING THE ROLE OF ENVIRONMENTAL PROCESSES IN GALAXY CLUSTERS  

SciTech Connect (OSTI)

In this work, we present the results of a novel approach devoted to disentangling the role of the environmental processes affecting galaxies in clusters. This is based on the analysis of the near-UV (NUV) - r' distributions of a large sample of star-forming galaxies in clusters spanning more than four absolute magnitudes. The galaxies inhabit three distinct environmental regions: virial regions, cluster infall regions, and field environment. We have applied rigorous statistical tests to analyze both the complete NUV - r' distributions and their averages for three different bins of the r'-band galaxy luminosity down to M{sub r{sup '}}{approx}-18, throughout the three environmental regions considered. We have identified the environmental processes that significantly affect the star-forming galaxies in a given luminosity bin by using criteria based on the characteristics of these processes: their typical timescales, the regions where they operate, and the galaxy luminosity range for which their effects are more intense. We have found that the high-luminosity (M{sub r{sup '}}{<=}-20) star-forming galaxies do not show significant signs in their star formation activity of being affected by: (1) the environment in the last {approx}10{sup 8} yr, or (2) a sudden quenching in the last 1.5 Gyr. The intermediate-luminosity (-20< M{sub r{sup '}}{<=}-19) star-forming galaxies appear to be affected by starvation in the virial regions and by the harassment in the virial and infall regions. Low-luminosity (-19

Hernandez-Fernandez, Jonathan D.; Vilchez, J. M.; Iglesias-Paramo, J., E-mail: jonatan@iaa.es [Instituto de Astrofisica de Andalucia, Glorieta de la Astronomia s/n, 18008 Granada (Spain)

2012-05-20T23:59:59.000Z

288

(Electronic structure and reactivities of transition metal clusters)  

SciTech Connect (OSTI)

The following are reported: theoretical calculations (configuration interaction, relativistic effective core potentials, polyatomics, CASSCF); proposed theoretical studies (clusters of Cu, Ag, Au, Ni, Pt, Pd, Rh, Ir, Os, Ru; transition metal cluster ions; transition metal carbide clusters; bimetallic mixed transition metal clusters); reactivity studies on transition metal clusters (reactivity with H{sub 2}, C{sub 2}H{sub 4}, hydrocarbons; NO and CO chemisorption on surfaces). Computer facilities and codes to be used, are described. 192 refs, 13 figs.

Not Available

1992-01-01T23:59:59.000Z

289

Calcium EXAFS establishes the Mn-Ca cluster in the oxygen-evolving complex of Photosystem II  

SciTech Connect (OSTI)

The proximity of Ca to the Mn cluster of the photosynthetic water-oxidation complex is demonstrated by X-ray absorption spectroscopy. We have collected EXAFS data at the Ca K-edge using active PS II membrane samples that contain approximately 2 Ca per 4 Mn. These samples are much less perturbed than previously investigated Sr-substituted samples, which were prepared subsequent to Ca depletion. The new Ca EXAFS clearly shows backscattering from Mn at 3.4 angstroms, a distance that agrees with that surmised from previously recorded Mn EXAFS. This result is also consistent with earlier related experiments at the Sr K-edge, using samples that contained functional Sr, that show Mn is {approx}; 3.5 angstroms distant from Sr. The totality of the evidence clearly advances the notion that the catalytic center of oxygen evolution is a Mn-Ca heteronuclear cluster.

Cinco, Roehl M.; McFarlane Holman, Karen L.; Robblee, John H.; Yano, Junko; Pizarro, Shelly A.; Bellacchio, Emanuele; Sauer, Kenneth; Yachandra, Vittal K.

2002-08-02T23:59:59.000Z

290

Testing the Distance–Duality Relation with Galaxy Clusters and Type Ia Supernovae  

Science Journals Connector (OSTI)

In this Letter, we propose a new and model-independent cosmological test for the distance-duality (DD) relation, ? = DL (z)(1 + z)–2/DA (z) = 1, where DL and DA are, respectively, the luminosity and angular diameter distances. For DL we consider two sub-samples of Type Ia supernovae (SNe Ia) taken from Constitution data whereas DA distances are provided by two samples of galaxy clusters compiled by De Filippis et al. and Bonamente et al. by combining Sunyaev-Zeldovich effect and X-ray surface brightness. The SNe Ia redshifts of each sub-sample were carefully chosen to coincide with the ones of the associated galaxy cluster sample (?z DA (z) ? DL (z), we have tested the DD relation by assuming that ? is a function of the redshift parameterized by two different expressions: ?(z) = 1 + ?0 z and ?(z) = 1 + ?0 z/(1 + z), where ?0 is a constant parameter quantifying a possible departure from the strict validity of the reciprocity relation (?0 = 0). In the best scenario (linear parameterization), we obtain ?0 = –0.28+0.44 –0.44 (2?, statistical + systematic errors) for the De Filippis et al. sample (elliptical geometry), a result only marginally compatible with the DD relation. However, for the Bonamente et al. sample (spherical geometry) the constraint is ?0 = –0.42+0.34 –0.34 (3?, statistical + systematic errors), which is clearly incompatible with the duality-distance relation.

R. F. L. Holanda; J. A. S. Lima; M. B. Ribeiro

2010-01-01T23:59:59.000Z

291

NifS-directed assembly of a transient [2Fe-2S] cluster within the NifU protein  

Science Journals Connector (OSTI)

...cluster formation. We have recently found that NifU is a modular protein with two distinct types of iron-binding sites (see...of an Air Products Displex model CSA-202E closed-cycle refrigerator. The sample temperature was maintained at 18 K during scanning...

Pramvadee Yuvaniyama; Jeffrey N. Agar; Valerie L. Cash; Michael K. Johnson; Dennis R. Dean

2000-01-01T23:59:59.000Z

292

Decoupled Sampling for Graphics Pipelines  

E-Print Network [OSTI]

We propose a generalized approach to decoupling shading from visibility sampling in graphics pipelines, which we call decoupled sampling. Decoupled sampling enables stochastic supersampling of motion and defocus blur at ...

Ragan-Kelley, Jonathan Millar

293

Fluid sampling apparatus and method  

DOE Patents [OSTI]

Incorporation of a bellows in a sampling syringe eliminates ingress of contaminants, permits replication of amounts and compression of multiple sample injections, and enables remote sampling for off-site analysis. 3 figs.

Yeamans, D.R.

1998-02-03T23:59:59.000Z

294

FT-ICR ,,,Carbon Clusters and Metal/Carbon Binary Clusters  

E-Print Network [OSTI]

60 70 80 720 760 800 Ion Mass [amu] ScC60 + C64 + Number of Carbon Atoms Intensity(arb.units) ScC60FT-ICR ,�,æ,éCarbon Clusters and Metal/Carbon Binary Clusters ·>Í­ì·³"¹1 ·C Masamichi Kohno1 , Tetsuya

Maruyama, Shigeo

295

Soil sampling kit and a method of sampling therewith  

DOE Patents [OSTI]

A soil sampling device and a sample containment device for containing a soil sample is disclosed. In addition, a method for taking a soil sample using the soil sampling device and soil sample containment device to minimize the loss of any volatile organic compounds contained in the soil sample prior to analysis is disclosed. The soil sampling device comprises two close fitting, longitudinal tubular members of suitable length, the inner tube having the outward end closed. With the inner closed tube withdrawn a selected distance, the outer tube can be inserted into the ground or other similar soft material to withdraw a sample of material for examination. The inner closed end tube controls the volume of the sample taken and also serves to eject the sample. The soil sample containment device has a sealing member which is adapted to attach to an analytical apparatus which analyzes the volatile organic compounds contained in the sample. The soil sampling device in combination with the soil sample containment device allows an operator to obtain a soil sample containing volatile organic compounds and minimizing the loss of the volatile organic compounds prior to analysis of the soil sample for the volatile organic compounds. 11 figures.

Thompson, C.V.

1991-02-05T23:59:59.000Z

296

Groundwater Sampling | Open Energy Information  

Open Energy Info (EERE)

Groundwater Sampling Groundwater Sampling Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Groundwater Sampling Details Activities (3) Areas (2) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Field Techniques Exploration Sub Group: Field Sampling Parent Exploration Technique: Water Sampling Information Provided by Technique Lithology: Stratigraphic/Structural: Hydrological: Water composition and source of fluids. Determination of mixing ratios between different fluid end-members. Determination of fluid recharge rates and residence times. Thermal: Water temperature. Dictionary.png Groundwater Sampling: Groundwater sampling is done to characterize the chemical, thermal, or hydrological properties of subsurface aqueous systems. Groundwater sampling

297

Water Sampling | Open Energy Information  

Open Energy Info (EERE)

Water Sampling Water Sampling Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Water Sampling Details Activities (51) Areas (45) Regions (5) NEPA(2) Exploration Technique Information Exploration Group: Field Techniques Exploration Sub Group: Field Sampling Parent Exploration Technique: Field Sampling Information Provided by Technique Lithology: Stratigraphic/Structural: Hydrological: Water composition and source of fluids Thermal: Water temperature Dictionary.png Water Sampling: Water sampling is done to characterize the chemical, thermal, or hydrological properties of a surface or subsurface aqueous system. Other definitions:Wikipedia Reegle Introduction Water sampling is done to characterize the geothermal system under investigation. A geothermal water typically has a unique chemical signature

298

Near-Infrared Observations of Globular Clusters in NGC 4472, NGC 4594, NGC 3585 and NGC 5813 and Implications for their Ages and Metallicities  

E-Print Network [OSTI]

We present near-infrared photometry of the globular cluster systems of the early-type galaxies NGC 4472, NGC 4594, NGC 3585, and NGC 5813. We combine these near-infrared data, obtained with PANIC at the Magellan Baade 6.5m telescope, with archival optical HST and FORS/VLT data, and use the optical to near-infrared colors to constrain the ages and metallicities of the globular clusters around the target galaxies. For NGC 4472 we have the most extensive near-infrared and optical photometric dataset. These colors show that the NGC 4472 globular cluster system has a broad metallicity distribution and that the clusters are predominantly old (i.e. ages of about 10 Gyr or more). This result agrees well with earlier spectroscopic work on NGC 4472, and is evidence that the combination of optical to near-infrared colors can identify predominantly old systems and distinguish these from systems with a substantial intermediate age component. Based on the smaller sample of combined optical and near-infrared data NGC 4594 and NGC 3585 appear to have predominantly old globular cluster systems, while that of NGC 5813 may have a more significant age spread. We also match our sample of globular clusters with near-infrared and optical photometry to Chandra X-ray source detections in these galaxies, and discuss how the probability that a globular cluster hosts a low-mass X-ray binary depends on metallicity and age.

Maren Hempel; Steve Zepf; Arunav Kundu; Doug Geisler; Thomas J. Maccarone

2007-02-19T23:59:59.000Z

299

Galaxy-cluster gas-density distributions of the Representative XMM-Newton Cluster Structure Survey (REXCESS)  

E-Print Network [OSTI]

We present a study of the structural and scaling properties of the gas distributions in the intracluster medium (ICM) of 31 nearby (z 3 keV scale self-similarly, with no temperature dependence of gas-density normalisation. We find some evidence of a correlation between dynamical state and outer gas density slope, and between dynamical state and both central gas normalisation and cooling time. We find no evidence of a significant bimodality in the distributions of central density, density gradient, or cooling time. Finally, we present the gas mass-temperature relation for the REXCESS sample, which is consistent with the expectation of self-similar scaling modified by the presence of an entropy excess in the inner regions of the cluster, and has a logarithmic intrinsic scatter of ~10%.

J. H. Croston; G. W. Pratt; H. Boehringer; M. Arnaud; E. Pointecouteau; T. J. Ponman; A. J. R. Sanderson; R. F. Temple; R. G. Bower; M. Donahue

2008-01-22T23:59:59.000Z

300

The Structure of Nuclear Star Clusters in Nearby Late-type Spiral Galaxies from Hubble Space Telescope Wide Field Camera 3 Imaging  

E-Print Network [OSTI]

We obtained Hubble Space Telescope/Wide Field Camera 3 imaging of a sample of ten of the nearest and brightest nuclear clusters residing in late-type spiral galaxies, in seven bands that span the near-ultraviolet to the near-infrared. Structural properties of the clusters were measured by fitting two-dimensional surface brightness profiles to the images using GALFIT. The clusters exhibit a wide range of structural properties. For six of the ten clusters in our sample, we find changes in the effective radius with wavelength, suggesting radially varying stellar populations. In four of the objects, the effective radius increases with wavelength, indicating the presence of a younger population which is more concentrated than the bulk of the stars in the cluster. However, we find a general decrease in effective radius with wavelength in two of the objects in our sample, which may indicate extended, circumnuclear star formation. We also find a general trend of increasing roundness of the clusters at longer waveleng...

Carson, Daniel J; Seth, Anil C; Brok, Mark den; Cappelari, Michele; Greene, Jenny E; Ho, Luis C; Neumayer, Nadine

2015-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Galaxy Clusters in the Swift/Burst Alert Telescope Era: Hard X-rays in the Intracluster Medium  

Science Journals Connector (OSTI)

We report the detection of 10 clusters of galaxies in the ongoing Swift/Burst Alert Telescope (BAT) all-sky survey. This sample, which mostly comprises merging clusters, was serendipitously detected in the 15-55 keV band. We use the BAT sample to investigate the presence of excess hard X-rays above the thermal emission. The BAT clusters do not show significant (e.g., ?2?) nonthermal hard X-ray emission. The only exception is represented by Perseus whose high-energy emission is likely due to NGC 1275. Using XMM-Newton, Swift/XRT, Chandra and BAT data, we are able to produce upper limits of the inverse Compton (IC) emission mechanism which are in disagreement with most of the previously-claimed hard X-ray excesses. The coupling of the X-ray upper limits of the IC mechanism to radio data shows that, in some clusters, the magnetic field might be larger than 0.5 ?G. We also derive the first log N-log S and luminosity function distributions of galaxy clusters above 15 keV.

M. Ajello; P. Rebusco; N. Cappelluti; O. Reimer; H. Böhringer; J. Greiner; N. Gehrels; J. Tueller; A. Moretti

2009-01-01T23:59:59.000Z

302

E-Print Network 3.0 - acs virgo cluster Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Block Schedule 202.05 The Low Mass X-ray ... Source: Sarazin, Craig - Department of Astronomy, University of Virginia Collection: Physics 2 INSTITUTE OF PHYSICS PUBLISHING...

303

E-Print Network 3.0 - advanced cluster analysis Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Data ... Source: Ravindran, Balaraman - Department of Computer Science and Engineering, Indian Institute of Technology Madras Collection: Computer Technologies and Information...

304

The duty cycle of radio-mode feedback in complete samples of clusters  

Science Journals Connector (OSTI)

......Waterloo, Waterloo, ON, N2L 2G1, Canada 4 Perimeter Institute for Theoretical Physics, Waterloo, ON, N2L 2Y5, Canada 5 Netherlands Institute for Radio Astronomy...632. ZuHoneJ. A., MarkevitchM., LeeD., 2011b, ApJ, 743, 16....

L. Bîrzan; D. A. Rafferty; P. E. J. Nulsen; B. R. McNamara; H. J. A. Röttgering; M. W. Wise; R. Mittal

2012-12-21T23:59:59.000Z

305

E-Print Network 3.0 - ant colony clustering Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Artificial Ants... - mization technique known as ant ... Source: Birattari, Mauro - Computer and Decision Engineering Department, Universit Libre de Bruxelles...

306

E-Print Network 3.0 - acpa automated cluster Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

an ASK system, a type of video-based organizational memory. The Air Campaign Planning Advisor (ACPA) uses... Advisor ACPA is composed of a Web-based ASK system linked to a...

307

E-Print Network 3.0 - atomic clusters irradiated Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

nanotubes encapsulating cobalt crystals Summary: to the shrinkage of the irradiated nanotubes due to atom sputtering 22 and defect migration 23... by a different mechanism...

308

E-Print Network 3.0 - aqueous clusters evaluated Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

|J. Phys. Chem. Lett. 2011, 2, 25152520 Summary: )2SO4, and Na2CO3 Relative to CaCl2 and NaCl at the AirAqueous Interface Revealed by Heterodyne... Information Water...

309

E-Print Network 3.0 - aluminum hydrogen cluster Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Collection: Energy Storage, Conversion and Utilization ; Renewable Energy 63 www.praxair.com Copyright 2003, Praxair Technology, Inc. All rights reserved. Summary:...

310

E-Print Network 3.0 - availability cluster system Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

for Moose Michael Meer Summary: extract subsystems and guide their exploration of the software system. There are many available properties... which properties matter most for his...

311

E-Print Network 3.0 - asthma patients clustering Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

and emergency room... visits to see if the patients live near known sources of air pollution. Under a CDC tracking grant... , and Drexel University of Philadel phia to...

312

E-Print Network 3.0 - anisotropic dynamic clustering Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

editor) Spatial analysis of dynamic movements of V... Velo'v Dynamic network Spatial data. 1 Introduction Community shared bicycle programs have been... , such...

313

E-Print Network 3.0 - alpha-cluster pickup reactions Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Prentiss, Mara - Department of Physics, Harvard University Collection: Physics 20 -Gator Lift scheduling requests must be submitted by 2 PM the day before you need...

314

E-Print Network 3.0 - aromatic hydrocarbon clusters Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

aliphatic chains as key intermediates for the nucleation Summary: to macromolecular building blocks (nanoparticles) that eventually turn into soot. Polycyclic aromatic...

315

Propensity to export and effects on cluster development: a comparative study of the Cyprus and Greek solar thermal clusters  

Science Journals Connector (OSTI)

Access to sophisticated demand is critical for cluster upgrading in developing countries. Despite this, the role of exports in cluster development has not been adequately researched. This study tries to answer two questions; what are the factors that increase the propensity of a cluster to successfully engage in exports and how exports affect cluster upgrading. In order to isolate the effect of exports, two clusters are studied, the Cyprus and the Greek solar thermal clusters. Despite the fact that these two clusters emerged in similar environments, today they present some distinct differences which could be explained by the different levels of success in exporting. Our findings suggest that the export vision shared among cluster participants, and the collaboration to achieve the vision are of critical importance in penetrating sophisticated export markets. This study highlights the positive influence of exports on cluster development and provides managers and policy makers with an indication of which factors contribute to successful exporting.

Andreas Petrou; Christos Maxoulis; Harris Haralambous

2008-01-01T23:59:59.000Z

316

Tetrahydrothiophene derivatives of metal carbonyl clusters  

Science Journals Connector (OSTI)

The cyclic thiother ligand tetrahydrothiophene, SC4H8, reacts with transition metal carbonyl clusters HRuCo3(CO)12, HRuRh3(CO)12, H4Ru4(CO)12 and Ru3(CO)12 to give HRuCo3(CO)11(SC4H8) (1), [HRuRh3(CO)9]2[SC4H8]3 (2), H2Ru4(CO)12(SC4H8) (3) and Ru4(CO)13(SC4H8) (4), respectively. The crystal structures of the products fall into three different structural types. In 1 the tetrahydrotriophene displaces a terminal carbonyl ligand at cobalt; whereas in 2 it acts as a bridging four-electron donor to give a dimerized cluster. Both Ru-clusters have butterfly structures with tetrahydrothiophene ligand coordinated between the wingtips.

Tiina Teppana; Sirpa Jääskeläinen; Markku Ahlgrén; Jouni Pursiainen; Tapani A. Pakkanen

1995-01-01T23:59:59.000Z

317

CO adsorption on neutral iridium clusters  

E-Print Network [OSTI]

The adsorption of carbon monoxide on neutral iridium clusters in the size range of n = 3 to 21 atoms is investigated with infrared multiple photon dissociation spectroscopy. For each cluster size only a single v(CO) band is present with frequencies in the range between 1962 cm-1 (n = 8) and 1985 cm-1 (n = 18) which can be attributed to an atop binding geometry. This behaviour is compared to the CO binding geometries on clusters of other group 9 and 10 transition metals as well as to that on extended surfaces. The preference of Ir for atop binding is rationalized by relativistic effects on the electronic structure of the later 5d metals.

Kerpal, Christian; Meijer, Gerard; Fielicke, André

2010-01-01T23:59:59.000Z

318

The Broadband Spectrum of Galaxy Clusters  

E-Print Network [OSTI]

We examine whether nonthermal protons energized during a cluster merger are simultaneously responsible for the Coma cluster's diffuse radio flux (via secondary decay) and the departure of its intra-cluster medium (ICM) from a thermal profile via Coulomb collisions between the quasithermal electrons and the hadrons. Rather than approximating the influence of nonthermal proton/thermal electron collisions as extremely rare events which cause an injection of nonthermal, power-law electrons (the `knock-on' approximation), we self-consistently solve (to our knowledge, for the first time) the covariant kinetic equations for the two populations. The electron population resulting from these collisions is out of equilibrium, yet not a power law, and importantly displays a higher bremsstrahlung radiative efficiency than a pure power law. Observations with GLAST will test this model directly.

Brandon Wolfe; Fulvio Melia

2007-12-02T23:59:59.000Z

319

Clustering and Triaxial Deformations of $^{40}$Ca  

E-Print Network [OSTI]

We have studied the positive-parity states of $^{40}$Ca using antisymmetrized molecular dynamics (AMD) and the generator coordinate method (GCM). Imposing two different kinds of constraints on the variational calculation, we have found various kinds of $^{40}{\\rm Ca}$ structures such as a deformed-shell structure, as well as $\\alpha$-$^{36}$Ar and $^{12}$C-$^{28}$Si cluster structures. After the GCM calculation, we obtained a normal-deformed band and a superdeformed band together with their side bands associated with triaxial deformation. The calculated $B(E2)$ values agreed well with empirical data. It was also found that the normal-deformed and superdeformed bands have a non-negligible $\\alpha$-$^{36}$Ar cluster component and $^{12}$C-$^{28}$Si cluster component, respectively. This leads to the presence of an $\\alpha$-$^{36}$Ar higher-nodal band occurring above the normal-deformed band.

Yasutaka Taniguchi; Masaaki Kimura; Yoshiko Kanada-En'yo; Hisashi Horiuchi

2007-07-05T23:59:59.000Z

320

Nonlinear Gravitational Clustering in Expanding Universe  

E-Print Network [OSTI]

The gravitational clustering of collisionless particles in an expanding universe is modelled using some simple physical ideas. I show that it is possible to understand the nonlinear clustering in terms of three well defined regimes: (1) linear regime; (2) quasilinear regime which is dominated by scale-invariant radial infall and (3) nonlinear regime dominated by nonradial motions and mergers. Modelling each of these regimes separately I show how the nonlinear two point correlation function can be related to the linear correlation function in hierarchical models. This analysis leads to results which are in good agreement with numerical simulations thereby providing an explanation for numerical results. Using this model and some simple extensions, it is possible to understand the transfer of power from large to small scales and the behaviour of higher order correlation functions. The ideas presented here will also serve as a powerful analytical tool to investigate nonlinear clustering in different models.

T. Padmanabhan

1996-07-19T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

SCALING RELATIONS AND OVERABUNDANCE OF MASSIVE CLUSTERS AT z {approx}> 1 FROM WEAK-LENSING STUDIES WITH THE HUBBLE SPACE TELESCOPE  

SciTech Connect (OSTI)

We present weak gravitational lensing analysis of 22 high-redshift (z {approx}> 1) clusters based on Hubble Space Telescope images. Most clusters in our sample provide significant lensing signals and are well detected in their reconstructed two-dimensional mass maps. Combining the current results and our previous weak-lensing studies of five other high-z clusters, we compare gravitational lensing masses of these clusters with other observables. We revisit the question whether the presence of the most massive clusters in our sample is in tension with the current {Lambda}CDM structure formation paradigm. We find that the lensing masses are tightly correlated with the gas temperatures and establish, for the first time, the lensing mass-temperature relation at z {approx}> 1. For the power-law slope of the M-T{sub X} relation (M{proportional_to}T{sup {alpha}}), we obtain {alpha} = 1.54 {+-} 0.23. This is consistent with the theoretical self-similar prediction {alpha} = 3/2 and with the results previously reported in the literature for much lower redshift samples. However, our normalization is lower than the previous results by 20%-30%, indicating that the normalization in the M-T{sub X} relation might evolve. After correcting for Eddington bias and updating the discovery area with a more conservative choice, we find that the existence of the most massive clusters in our sample still provides a tension with the current {Lambda}CDM model. The combined probability of finding the four most massive clusters in this sample after the marginalization over cosmological parameters is less than 1%.

Jee, M. J.; Lubin, L.; Stanford, S. A. [Department of Physics, University of California, Davis, One Shields Avenue, Davis, CA 95616 (United States); Dawson, K. S.; Harris, D. W. [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Hoekstra, H. [Leiden Observatory, Leiden University, Leiden (Netherlands); Perlmutter, S.; Suzuki, N.; Meyers, J.; Barbary, K. [E.O. Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley CA 94720 (United States); Rosati, P. [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748, Garching (Germany); Brodwin, M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Koester, B.; Gladders, M. D. [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States); Postman, M. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Barrientos, F. [Department of Astronomy and Astrophysics, Universidad Catolica de Chile, Santiago (Chile); Eisenhardt, P. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Ford, H. C. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Gilbank, D. G. [Department of Physics and Astronomy, University Of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Gonzalez, A. [Department of Astronomy, University of Florida, Gainesville, FL 32611-2055 (United States)

2011-08-20T23:59:59.000Z

322

Relaxing the constraints of clustered planarity  

Science Journals Connector (OSTI)

Abstract In a drawing of a clustered graph vertices and edges are drawn as points and curves, respectively, while clusters are represented by simple closed regions. A drawing of a clustered graph is c-planar if it has no edge–edge, edge–region, or region–region crossings. Determining the complexity of testing whether a clustered graph admits a c-planar drawing is a long-standing open problem in the Graph Drawing research area. An obvious necessary condition for c-planarity is the planarity of the graph underlying the clustered graph. However, this condition is not sufficient and the consequences on the problem due to the requirement of not having edge–region and region–region crossings are not yet fully understood. In order to shed light on the c-planarity problem, we consider a relaxed version of it, where some kinds of crossings (either edge–edge, edge–region, or region–region) are allowed even if the underlying graph is planar. We investigate the relationships among the minimum number of edge–edge, edge–region, and region–region crossings for drawings of the same clustered graph. Also, we consider drawings in which only crossings of one kind are admitted. In this setting, we prove that drawings with only edge–edge or with only edge–region crossings always exist, while drawings with only region–region crossings may not. Further, we provide upper and lower bounds for the number of such crossings. Finally, we give a polynomial-time algorithm to test whether a drawing with only region–region crossings exists for biconnected graphs, hence identifying a first non-trivial necessary condition for c-planarity that can be tested in polynomial time for a noticeable class of graphs.

Patrizio Angelini; Giordano Da Lozzo; Giuseppe Di Battista; Fabrizio Frati; Maurizio Patrignani; Vincenzo Roselli

2015-01-01T23:59:59.000Z

323

Supersonic Bare Metal Cluster Beams. Final Report  

DOE R&D Accomplishments [OSTI]

A major portion of the project involved elucidating the relation between reactivity and the electronic structure of transition-metal (TM) clusters of 2--200 atoms, which required the construction and continuous development of two principal apparati; the Fourier Transform-Ion Cyclotron Resonance (FT-ICR) apparatus, and Ultraviolet Photoelectron Spectroscopy (UPS). Together, these machines have enabled the most detailed probing of the structure and chemical reactivity of TM clusters. Clusters of all the transition metals were included in these studies. Fundamental aspects in chemisorption, reactivity, and heterogeneous catalysis have also become better understood as a result of these experiments for important classes of systems such as H{sub 2}, CO, and CO{sub 2} adsorbed onto clusters of many of the metals listed above. In particular, a correlation was found between reactivity of H{sub 2} with Fe, Co, and Ni clusters and differences between the cluster IP and EA. As recounted in a previous technical report, the DOE`s role in the initial discovery of fullerenes at Rice was central, and from the start investigations were made into metal atoms trapped in the fullerenes cage. More recently, the authors have discovered that 2--4 atoms of La, Y, or Sc can be produced by laser vaporization of composite graphite/metal-oxide disks. This work was largely motivated by the prospects of using such endohedral TM metals for their catalytic activity without the well-known difficulties of effective support media and lack of control over particle size. Thus, while it will certainly be important to discover ways to efficiently scale up production (e.g., the solar generation method explored with DOE support), the efforts have concentrated more on characterization, purification, and manipulation of doped fullerenes. For the past two years, much of the group`s effort has involved the production, purification, and characterization of carbon nanotubes.

Smalley, R. E.

1997-10-14T23:59:59.000Z

324

Gas Sampling | Open Energy Information  

Open Energy Info (EERE)

Gas Sampling Gas Sampling Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Gas Sampling Details Activities (7) Areas (7) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Field Techniques Exploration Sub Group: Field Sampling Parent Exploration Technique: Field Sampling Information Provided by Technique Lithology: Stratigraphic/Structural: High flux can be indicative of conduits for fluid flow. Hydrological: Gas composition and source of fluids. Thermal: Anomalous flux is associated with active hydrothermal activity. Distinguish magmatic/mantle heat inputs. Can be used to estimate reservoir fluid temperatures. Dictionary.png Gas Sampling: Gas sampling is done to characterize the chemical, thermal, and hydrological properties of a surface or subsurface hydrothermal system.

325

Stack sampling apparatus  

SciTech Connect (OSTI)

An apparatus for obtaining samples from a structure includes a support member, at least one stabilizing member, and at least one moveable member. The stabilizing member has a first portion coupled to the support member and a second portion configured to engage with the structure to restrict relative movement between the support member and the structure. The stabilizing member is radially expandable from a first configuration where the second portion does not engage with a surface of the structure to a second configuration where the second portion engages with the surface of the structure.

Lind, Randall F; Lloyd, Peter D; Love, Lonnie J; Noakes, Mark W; Pin, Francois G; Richardson, Bradley S; Rowe, John C

2014-09-16T23:59:59.000Z

326

Cosmology with X-ray Cluster Baryons  

SciTech Connect (OSTI)

X-ray cluster measurements interpreted with a universal baryon/gas mass fraction can theoretically serve as a cosmological distance probe. We examine issues of cosmological sensitivity for current (e.g., Chandra X-ray Observatory, XMM-Newton) and next generation (e.g., Con-X, XEUS) observations, along with systematic uncertainties and biases. To give competitive next generation constraints on dark energy, we find that systematics will need to be controlled to better than 1percent and any evolution in f_gas (and other cluster gas properties) must be calibrated so the residual uncertainty is weaker than (1+z)0.03.

Linder, Eric V.

2007-04-10T23:59:59.000Z

327

X-ray sources in globular clusters  

E-Print Network [OSTI]

The twelve bright (Lx>10(36) erg/s) X-ray sources in the globular clusters have lower luminosities than the brightest sources in the bulge of our galaxy. The dim (Lx<10(35) erg/s) X-ray sources in globular clusters reach higher luminosities than the cataclysmic variables in the disk of our galaxy. The first difference is a statistical fluke, as comparison with M31 indicates. The second difference is explained because the brightest of the dim sources are not cataclysmic variables, but soft X-ray transients in quiescence. This article describes the BeppoSAX, ROSAT and first Chandra observations leading to these conclusions.

Frank Verbunt

2001-11-22T23:59:59.000Z

328

Likelihood Methods for Cluster Dark Energy Surveys  

E-Print Network [OSTI]

Galaxy cluster counts at high redshift, binned into spatial pixels and binned into ranges in an observable proxy for mass, contain a wealth of information on both the dark energy equation of state and the mass selection function required to extract it. The likelihood of the number counts follows a Poisson distribution whose mean fluctuates with the large-scale structure of the universe. We develop a joint likelihood method that accounts for these distributions. Maximization of the likelihood over a theoretical model that includes both the cosmology and the observable-mass relations allows for a joint extraction of dark energy and cluster structural parameters.

Wayne Hu; J. D. Cohn

2006-02-07T23:59:59.000Z

329

Icosahedral structure in hydrogenated cobalt and nickel clusters  

SciTech Connect (OSTI)

Reactions with ammonia and with water are used to probe the geometrical structures of cobalt and nickel clusters that are saturated with hydrogen. Ammonia saturation experiments allow the determination of the number of primary NH{sub 3} binding sites on cluster surfaces, and this number shows a repeated minimization to values of 12 for many cluster sizes in the 50- to 200-atom size region. These sizes correspond to closed shells and subshells of icosahedra, suggesting that the ammoniated clusters have metal frameworks with icosahedral structure. The equilibrium reaction of the hydrogenated clusters with a single water molecule shows a pattern of local maxima in the cluster--water binding energy, with the maxima in most cases coming at clusters having one metal atom more than those showing minima in ammonia binding. This correlation suggests that nonammoniated clusters likewise have icosahedral structure, and is consistent with the nature of the metal--water interaction. Some of the larger clusters do not show clear evidence for icosahedral structure at room temperature, although they begin to do so at elevated temperature. Annealing experiments suggest that many of these clusters are icosahedral in their most stable configuration at room temperature, although the 147-atom nickel cluster is not. In general, hydrogenation enhances the icosahedral features in the ammonia and water binding patterns compared to those seen for bare clusters, and extends the cluster size region over which icosahedral structure is evident.

Klots, T.D.; Winter, B.J.; Parks, E.K.; Riley, S.J. (Chemistry Division, Argonne National Laboratory, Argonne, Illinois (USA))

1991-12-15T23:59:59.000Z

330

Fluid sampling tool  

DOE Patents [OSTI]

A fluid sampling tool is described for sampling fluid from a container. The tool has a fluid collecting portion which is drilled into the container wall, thereby affixing it to the wall. The tool may have a fluid extracting section which withdraws fluid collected by the fluid collecting section. The fluid collecting section has a fluted shank with an end configured to drill a hole into a container wall. The shank has a threaded portion for tapping the borehole. The shank is threadably engaged to a cylindrical housing having an inner axial passageway sealed at one end by a septum. A flexible member having a cylindrical portion and a bulbous portion is provided. The housing can be slid into an inner axial passageway in the cylindrical portion and sealed to the flexible member. The bulbous portion has an outer lip defining an opening. The housing is clamped into the chuck of a drill, the lip of the bulbous section is pressed against a container wall until the shank touches the wall, and the user operates the drill. Wall shavings (kerf) are confined in a chamber formed in the bulbous section as it folds when the shank advances inside the container. After sufficient advancement of the shank, an o-ring makes a seal with the container wall. 6 figs.

Garcia, A.R.; Johnston, R.G.; Martinez, R.K.

1999-05-25T23:59:59.000Z

331

Power spectrum normalization from the local abundance of rich clusters of galaxies  

E-Print Network [OSTI]

The number density of rich galaxy clusters still provides the most robust way of normalizing the power spectrum of dark matter perturbations on scales relevant to large-scale structure. We revisit this constraint in light of several recent developments: (1) the availability of well-defined samples of local clusters with relatively accurate X-ray temperatures; (2) new theoretical mass functions for dark matter haloes which provide a good fit to large numerical simulations; (3) more accurate mass-temperature relations from larger catalogs of hydrodynamical simulations; (4) the requirement to consider closed as well as open and flat cosmologies to obtain full multi-parameter likelihood constraints for CMB and SNe studies. We present a new sample of clusters drawn from the literature and use this sample to obtain improved results on sigma_8, the normalization of the matter power spectrum on scales of 8 h^{-1} Mpc, as a function of the matter density and cosmological constant in a Universe with general curvature. We discuss our differences with previous work, and the remaining major sources of uncertainty. Final results on the 68 per cent confidence region, approximately independent of power spectrum shape, can be expressed as constraints on sigma at an appropriate cluster normalization scale R_Cl. We provide fitting formulas for R_Cl and sigma(R_Cl) for general cosmologies, as well as for sigma_8 as a function of cosmology and shape parameter Gamma. For flat models we find approximately sigma_8 \\simeq 0.495^{+0.034}_{-0.037}) Omega_M^{-0.60} for Gamma=0.23, where the error bar is dominated by uncertainty in the mass-temperature relation.

E. Pierpaoli; D. Scott; M. White

2001-09-27T23:59:59.000Z

332

Spectral energy distributions and age estimates of 104 M31 globular clusters  

E-Print Network [OSTI]

We present photometry of 104 M31 globular clusters (GCs) and GC candidates in 15 intermediate-band filters of the Beijing-Arizona-Taiwan-Connecticut (BATC) photometric system. The GCs and GC candidates were selected from the Revised Bologna Catalog (v.3.5). We obtain the cluster ages by comparing the photometric data with up-to-date theoretical synthesis models. The photometric data used are {\\sl GALEX} far- and near-ultraviolet and 2MASS near-infrared $JHK_{\\rm s}$ magnitudes, combined with optical photometry. The ages of our sample clusters cover a large range, although most clusters are younger than 10 Gyr. Combined with the ages obtained in our series of previous papers focusing on the M31 GC system, we present the full M31 GC age distribution. The M31 GC system contains populations of young and intermediate-age GCs, as well as the `usual' complement of well-known old GCs, i.e., GCs of similar age as the majority of the Galactic GCs. In addition, young GCs (and GC candidates) are distributed nearly unifor...

Wang, Song; Ma, Jun; de Grijs, Richard; Zhou, Xu

2010-01-01T23:59:59.000Z

333

Radial velocities from VLT-KMOS spectra of giant stars in the globular cluster NGC 6388  

E-Print Network [OSTI]

We present new radial velocity measurements for 82 stars, members of the Galactic globular cluster NGC 6388, obtained from ESO-VLT KMOS spectra acquired during the instrument Science Verification. The accuracy of the wavelength calibration is discussed and a number of tests of the KMOS response are presented. The cluster systemic velocity obtained (81.3 +/- 1.5 km/sec) is in very good agreement with previous determinations. While a hint of ordered rotation is found between 9'' and 20'' from the cluster centre, where the distribution of radial velocities is clearly bimodal, more data are needed before drawing any firm conclusions. The acquired sample of radial velocities has been also used to determine the cluster velocity dispersion profile between ~9'' and 70'', supplementing previous measurements at r 60'' obtained with ESO-SINFONI and ESO-FLAMES spectroscopy, respectively. The new portion of the velocity dispersion profile nicely matches the previous ones, better defining the knee of the distribution. The...

Lapenna, Emilio; Mucciarelli, Alessio; Lanzoni, Barbara; Ferraro, Francesco Rosario; Dalessandro, Emanuele; Valenti, Elena; Cirasuolo, Michele

2014-01-01T23:59:59.000Z

334

An explanation for long flares from extragalactic globular cluster X-ray sources  

E-Print Network [OSTI]

Repeatedly flaring X-ray binaries have recently been discovered in NGC 4697 by Sivakoff and collaborators. We show that these flares can be explained as the result of eccentric binaries in globular clusters which accrete more rapidly at periastron than during the rest of the binary orbit. We show that theoretical timescales for producing eccentricities and circularising the binaries are consistent with what is needed to produce the observed population of flaring sources, although the circularisation timescales are highly uncertain on both observational and theoretical grounds. This model makes two clear theoretical predictions (1) the flares should be seen to be strictly periodic if adequate sampling is provided, and that periodicity should be of approximately 15 hours (2) this class of flaring behaviour should be seen only in globular cluster sources, and predominantly in the densest globular clusters. We also test the model for producing eccentricities through fly-by's of a third star near the binary in a globular cluster against a much larger database of millisecond pulsar observations than has been used in past work, and find that the theoretical cross sections for producing eccentricity in binaries are in reasonable agreement with most of the data, provided that the pulsar ages are about $4\\times10^9$ years.

Thomas J. Maccarone

2005-09-21T23:59:59.000Z

335

GeV Gamma-ray Flux Upper Limits from Clusters of Galaxies  

E-Print Network [OSTI]

The detection of diffuse radio emission associated with clusters of galaxies indicates populations of relativistic leptons infusing the intracluster medium. Those electrons and positrons are either injected into and accelerated directly in the intracluster medium, or produced as secondary pairs by cosmic-ray ions scattering on ambient protons. Radiation mechanisms involving the energetic leptons together with decay of neutral pions produced by hadronic interactions have the potential to produce abundant GeV photons. Here, we report on the search for GeV emission from clusters of galaxies using data collected by the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope (Fermi) from August 2008 to February 2010. Thirty-three galaxy clusters have been selected according to their proximity and high mass, X-ray flux and temperature, and indications of non-thermal activity for this study. We report upper limits on the photon flux in the range 0.2-100 GeV towards a sample of observed clusters (typical va...

al., M Ackermann et

2010-01-01T23:59:59.000Z

336

A DETAILED STATISTICAL ANALYSIS OF THE MASS PROFILES OF GALAXY CLUSTERS  

SciTech Connect (OSTI)

The distribution of mass in the halos of galaxies and galaxy clusters has been probed observationally, theoretically, and in numerical simulations, yet there is still confusion about which of several suggested parameterized models is the better representation, and whether these models are universal. We use the temperature and density profiles of the intracluster medium as measured by X-ray observations of 11 relaxed galaxy clusters to investigate mass models for the halo using a thorough Bayesian statistical analysis. We make careful comparisons between two- and three-parameter models, including the issue of a universal third parameter. We find that, of the two-parameter models, the Navarro-Frenk-White (NFW) is the best representation, but we also find moderate statistical evidence that a generalized three-parameter NFW model with a freely varying inner slope is preferred, despite penalizing against the extra degree of freedom. There is a strong indication that this inner slope needs to be determined for each cluster individually, i.e., some clusters have central cores and others have steep cusps. The mass-concentration relation of our sample is in reasonable agreement with predictions based on numerical simulations.

Host, Ole [Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT (United Kingdom); Hansen, Steen H. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark)

2011-07-20T23:59:59.000Z

337

Argonne CNM News: Charge Separation in Silver Clusters  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Charge Separation in Silver Clusters Charge Separation in Silver Clusters silver clusters Artist's rendering of silver clusters capped with organic ligand molecules. transient kinetics of silver clusters Transient kinetics showing charge recombination in ligand-stabilized silver clusters for different surrounding solvents (water-methanol mixture, acetone, and dichloromethane). Both charge separation and recombination events are faster in more polar solvents. Center for Nanoscale Materials (CNM) users from the Ecole Polytechnique Federale de Lausanne in Switzerland, working with the CNM Nanophotonics Group, have demonstrated the existence of long-lived charge-separated states in silver clusters. The clusters, synthesized chemically in solution, consist of exactly 44 silver atoms and are stabilized by exactly

338

Multi-view spectral clustering and its chemical application  

Science Journals Connector (OSTI)

Clustering is an unsupervised method that allows researchers to group objects and gather information about their relationships. In chemoinformatics, clustering enables hypotheses to be drawn about a compound's biological, chemical and physical property in comparison to another. We introduce a novel improved spectral clustering algorithm, proposed for chemical compound clustering, using multiple data sources. Tensor-based spectral methods, used in this paper, provide chemically appropriate and statistically significant results when attempting to cluster compounds from both the GSK-Chembl Malaria data set and the Zinc database. Spectral clustering algorithms based on the tensor method give robust results on the mid-size compound sets used here. The goal of this paper is to present the clustering of chemical compounds, using a tensor-based multi-view method which proves of value to the medicinal chemistry community. Our findings show compounds of extremely different chemotypes clustering together, this is a hint to the chemogenomics nature of our method.

Adeshola A. Adefioye; Xinhai Liu; Bart De Moor

2013-01-01T23:59:59.000Z

339

On the Ising Problem and Mayer's Cluster Sums  

Science Journals Connector (OSTI)

12 June 1955 research-article On the Ising Problem and Mayer's Cluster Sums G. S. Rushbrooke H. I. Scoins When Mayer's imperfect-gas formalism is applied to the Ising problem emphasis is focused on certain irreducible cluster sums...

1955-01-01T23:59:59.000Z

340

A knowledge-driven approach to cluster validity assessment  

Science Journals Connector (OSTI)

......other APPLICATIONS NOTE Gene expression A knowledge-driven approach to cluster validity...cluster validity based on similarity knowledge extracted from the Gene Ontology. Availability...The automated integration of background knowledge is fundamental to support the generation......

Nadia Bolshakova; Francisco Azuaje; Pádraig Cunningham

2005-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Self-service queue and user management in shared clusters  

Science Journals Connector (OSTI)

Under a shared campus cluster model, with many different investing research groups, and annual new cluster acquisitions, constantly adding and removing students and collaborators from resources owned by partner faculty, campus IT staff set out to design ...

Kevin D. Colby, Daniel T. Dietz, Preston M. Smith, Donna D. Cumberland

2014-11-01T23:59:59.000Z

342

Graph degree linkage: agglomerative clustering on a directed graph  

Science Journals Connector (OSTI)

This paper proposes a simple but effective graph-based agglomerative algorithm, for clustering high-dimensional data. We explore the different roles of two fundamental concepts in graph theory, indegree and outdegree, in the context of clustering. The ...

Wei Zhang; Xiaogang Wang; Deli Zhao; Xiaoou Tang

2012-10-01T23:59:59.000Z

343

Preliminary Experiment for the Control of Cluster Vibration  

E-Print Network [OSTI]

(= 32.8 nm) to probe the vibration. The absorption of x-ray pulses is measured. We want to find of Cluster Vibration for the Control of Cluster Vibration 99 7 20 1. 15 3 http

344

Beltrami Equation and Cluster Lensing: Characteristic Equations and Applications  

E-Print Network [OSTI]

Arclets in clusters of galaxies can be used to determine the lens mapping and not only to constrain the mass density of the cluster. Multiply imaged arclets are therefore easily identified without further modelling.

Schramm; T

1995-07-24T23:59:59.000Z

345

CDM vs. MOND The Coma cluster  

E-Print Network [OSTI]

Cluster. Velocities and distances from centre total mass. #12;Dark matter! #12;Zwickys discovery Zwickys discovery to a phenomenon (cmp- Bailer-Jones): Dark Matter But later, the discussion actually.73 ± 0.04 (dark energy) (Bennett et al 2003, Spergel et al 2006) All 3 ingredients comparable

Korn, Andreas

346

10 years of the Cluster mission  

Science Journals Connector (OSTI)

......reaches a critical point; the flux is then...rocket carrying the four Cluster spacecraft exploded soon after lift off from Kourou...spacecraft and, just four years later on...provide an important point of entry for solar...provide the necessary four point measurements to......

Andrew P Walsh; C Forsyth; A N Fazakerley; C H K Chen; E A Lucek; J A Davies; C H Perry; S N Walker; M A Balikhin

2010-10-01T23:59:59.000Z

347

Cluster-based find and replace  

Science Journals Connector (OSTI)

In current text editors, the find & replace command offers only two options: replace one match at a time prompting for confirmation, or replace all matches at once without any confirmation. Both approaches are prone to errors. This paper explores a third ... Keywords: clustering, error prevention, find & replace, text editing

Robert C. Miller; Alisa M. Marshall

2004-04-01T23:59:59.000Z

348

APPROXIMATION ALGORITHMS FOR CLUSTERING A Dissertation  

E-Print Network [OSTI]

develop new algorithmic techniques that will find application in a wide range of settings. We consider problems such as the stochastic versions of the set cover, vertex cover, and facility location problemsAPPROXIMATION ALGORITHMS FOR CLUSTERING PROBLEMS A Dissertation Presented to the Faculty

Swamy, Chaitanya

349

Optimizing Path Query Performance: Graph Clustering Strategies  

E-Print Network [OSTI]

ywh@us.ibm.com Ning Jingz Changsha Institute of Technology jning@eecs.umich.edu Elke A. Rundensteinerx not incur any run-time cost, requires no auxiliary data structures, and is complimentary to many of the performance of these graph clustering techniques using an actual city road network as well as randomly

350

College of Engineering High Performance Computing Cluster  

E-Print Network [OSTI]

College of Engineering High Performance Computing Cluster Policy and Procedures COE-HPC-01 and registered as requiring high performance computing; the course identification/registrations process the College High Performance Computing system will need register for system access by visiting http

Demirel, Melik C.

351

Molecular Cluster Perturbation Theory. I. Formalism  

E-Print Network [OSTI]

We present second-order molecular cluster perturbation theory (MCPT(2)), a methodology to calculate arbitrarily large systems with explicit calculation of individual wavefunctions in a coupled-cluster framework. This new MCPT(2) framework uses coupled-cluster perturbation theory and an expansion in terms of molecular dimer interactions to obtain molecular wavefunctions that are infinite-order in both the electronic fluctuation operator and all possible dimer (and products of dimers) interactions. The MCPT(2) framework has been implemented in the new SIA/ACES parallel architecture, making use of the advanced dynamic memory control and fine grained parallelism to perform very large explicit molecular cluster calculations. To illustrate the power of this method, we have computed energy shifts and lattice site dipole moments via explicit calculation of the bulk system for the polar and non-polar configurations of solid hydrogen fluoride. The explicit lattice size without periodic boundary conditions was expanded up to 1,000 HF molecules, with 32,000 basis functions and 10,000 electrons. Our obtained HF lattice site dipole moments of 2.51 and 2.49 Debye (for the polar and non-polar configurations, respectively) are in good agreement with the existing literature values of 2.51 and 2.47.

Jason N. Byrd; Nakul Jindal; Robert W. Molt, Jr.; Rodney J. Bartlett; Beverly A. Sanders; Victor F. Lotrich

2014-09-06T23:59:59.000Z

352

Experimental confirmation of cluster-impact fusion  

Science Journals Connector (OSTI)

We have investigated deuteron-deuteron fusion induced by impact of (D2O)n+ and (H2O)n+ clusters with n=1–150 on deuterated polyethylene targets at energies of 135–225 keV. Both the energy dependence and magnitude of the fusion yield measured with (D2O)115+ clusters confirm the results of Beuhler et al. [J. Phys. Chem. 94, 7665 (1990)]. Furthermore, we have observed that the size dependence of the (D2O)n+ fusion yields measured at the impact energy of 225 keV for small (nthermonuclear’’ model proposed by Carraro et al. [Phys. Rev. A 42, 1379 (1990)] rather than the thick-target model. For H2O+ and (H2O)2+ at 225 keV, the yields roughly agree with the ‘‘knock-on’’ model by Carraro et al. No fusion event was observed for (H2O)n+ clusters with n=4–50; however, n=115 clusters produced an observable fusion rate. The ratio between fusion rates of (H2O)115+ and (D2O)115+ is 5%±2%, in close agreement with the result, ?5%, measured by Beuhler et al. at 300 keV.

Y. K. Bae; D. C. Lorents; S. E. Young

1991-10-01T23:59:59.000Z

353

Cosmological implications of galaxy cluster evolution  

Science Journals Connector (OSTI)

......the best-fitting parameters at various red- shifts. Consider first the bimodal cluster...P4 /PO) but a less pronounced aggre- gate, larger scale structure (less Pz/Po...Kaiser N., Babul A., Fahlman G., Woods D., Neumann D. M., Bohringer H......

John C. Tsai; David A. Buote

1996-09-01T23:59:59.000Z

354

Modeling the Energy Efficiency of Heterogeneous Clusters  

E-Print Network [OSTI]

on heterogeneous clusters ­ Unexplored from energy-time performance perspective 10-Sep-14 ICPP 2014 7 #12;Objectiveth September 2014 43rd International Conference on Parallel Processing, Minneapolis, MN, USA #12;Outline · Motivation · Objective · Methodology · Analysis · Conclusions 10-Sep-14 2ICPP 2014 #12;Energy

Teo, Yong-Meng

355

BOUNDS FOR SPECTRAL CLUSTERS HART F. SMITH  

E-Print Network [OSTI]

Lq BOUNDS FOR SPECTRAL CLUSTERS HART F. SMITH Abstract. In these notes, we review recent results] establish the same estimates under the assumption that the metric is C1,1. It is known by examples of Smith to the wave equation. The author was supported in part by NSF grant DMS-0140499. 1 #12;2 HART F. SMITH

Smith, Hart F.

356

February 22, 1998 Clustering ECG Complexes Using  

E-Print Network [OSTI]

LU TP 98­1 February 22, 1998 Clustering ECG Complexes Using Hermite Functions and Self Transactions on Biomedical Engineering Abstract: An integrated method for identifying and classifying ECG for analysis and interpretation of ECGs have been subject to intense research for nearly four decades

Lunds Universitet,

357

THE CLUSTERING OF GALAXIES IN THE SDSS-III BARYON OSCILLATION SPECTROSCOPIC SURVEY: LUMINOSITY AND COLOR DEPENDENCE AND REDSHIFT EVOLUTION  

SciTech Connect (OSTI)

We measure the luminosity and color dependence and the redshift evolution of galaxy clustering in the Sloan Digital Sky Survey-III Baryon Oscillation Spectroscopic Survey Ninth Data Release. We focus on the projected two-point correlation function (2PCF) of subsets of its CMASS sample, which includes about 260,000 galaxies over {approx}3300 deg{sup 2} in the redshift range 0.43 < z < 0.7. To minimize the selection effect on galaxy clustering, we construct well-defined luminosity and color subsamples by carefully accounting for the CMASS galaxy selection cuts. The 2PCF of the whole CMASS sample, if approximated by a power-law, has a correlation length of r{sub 0} = 7.93 {+-} 0.06 h {sup -1} Mpc and an index of {gamma} = 1.85 {+-} 0.01. Clear dependences on galaxy luminosity and color are found for the projected 2PCF in all redshift bins, with more luminous and redder galaxies generally exhibiting stronger clustering and steeper 2PCF. The color dependence is also clearly seen for galaxies within the red sequence, consistent with the behavior of SDSS-II main sample galaxies at lower redshifts. At a given luminosity (k + e corrected), no significant evolution of the projected 2PCFs with redshift is detected for red sequence galaxies. We also construct galaxy samples of fixed number density at different redshifts, using redshift-dependent magnitude thresholds. The clustering of these galaxies in the CMASS redshift range is found to be consistent with that predicted by passive evolution. Our measurements of the luminosity and color dependence and redshift evolution of galaxy clustering will allow for detailed modeling of the relation between galaxies and dark matter halos and new constraints on galaxy formation and evolution.

Guo Hong; Zehavi, Idit [Department of Astronomy, Case Western Reserve University, OH 44106 (United States); Zheng Zheng [Department of Physics and Astronomy, University of Utah, UT 84112 (United States); Weinberg, David H. [Department of Astronomy and CCAPP, Ohio State University, Columbus, OH 43210 (United States); Berlind, Andreas A. [Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235 (United States); Blanton, Michael [Center for Cosmology and Particle Physics, New York University, New York, NY 10003 (United States); Chen Yanmei [Department of Astronomy, Nanjing University, Nanjing 210093 (China); Eisenstein, Daniel J.; McBride, Cameron K. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Ho, Shirley; Ross, Nicholas P. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Kazin, Eyal [Center for Astrophysics and Supercomputing, Swinburne University of Technology, P.O. Box 218, Hawthorn, Victoria 3122 (Australia); Manera, Marc; Maraston, Claudia; Percival, Will J.; Ross, Ashley J.; Samushia, Lado [Institute of Cosmology and Gravitation, Dennis Sciama Building, University of Portsmouth, Portsmouth, PO1 3FX (United Kingdom); Nuza, Sebastian E. [Leibniz-Institut fuer Astrophysik Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany); Padmanabhan, Nikhil; Parejko, John K. [Department of Physics, Yale University, 260 Whitney Ave, New Haven, CT 06520 (United States); and others

2013-04-20T23:59:59.000Z

358

A COMPARISON OF ARTIFICIAL NEURAL NETWORKS AND CLUSTER ANALYSIS FOR TYPING BIOMETRICS  

E-Print Network [OSTI]

A COMPARISON OF ARTIFICIAL NEURAL NETWORKS AND CLUSTER ANALYSIS FOR TYPING BIOMETRICS biometrics, artificial neural networks, cluster analysis, Multi Layer Perceptrons, K- means clustering are clustering techniques and Artificial Neural Networks , in conjunction with data processing to improve

359

Size-selected Metal Cluster Deposition on Oxide Surfaces: Impact Dynamics and Supported Cluster Chemistry  

E-Print Network [OSTI]

Lens Quadrupole Ion Guide 3 Focusing Lens Deposition Stage Electron Multiplier Isolation Valve4 Au3 Au2 Au Constant signal = constant sticking coefficient ~1.0 No shifts with cluster size

Anderson, Scott L.

360

Galaxy Clustering in the CNOC2 Redshift Survey  

E-Print Network [OSTI]

The correlation evolution of a high luminosity subsample of the CNOC2 redshift survey is examined. The sample is restricted to galaxies for which the k corrected and evolution corrected R luminosity is M_R <=-20 mag, where M_* ~= -20.3 mag. This subsample contains about 2300 galaxies. In consort with 13000 galaxies in a similarly defined low redshift sample from the Las Campanas Redshift survey we find that the comoving correlation can be described as xi(r|z) = (r_00/r)^gamma (1+z)^{-(3+e)} with r_00=5.08 +/- 0.08/h Mpc, e=0.02 +/- 0.23 and gamma=1.81 +/- 0.03 over the z=0.03 to 0.65 redshift range in a cosmology with Omega_M=0.2, Lambda=0. The measured clustering amplitude, and its evolution, are dependent on the adopted cosmology. The evolution rates for Omega_M=1 and flat low density models are e=0.9 +/- 0.3 and e=-0.5 +/- 0.2, respectively, with r_00 ~= 5/h Mpc in all cases.

R. G. Carlberg; H. K. C. Yee; S. L. Morris; H. Lin; P. Hall; D. Patton; M. Sawicki; C. W. Shepherd

1999-10-06T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

THERMODYNAMICS OF THE COMA CLUSTER OUTSKIRTS  

SciTech Connect (OSTI)

We present results from a large mosaic of Suzaku observations of the Coma Cluster, the nearest and X-ray brightest hot ({approx}8 keV), dynamically active, non-cool core system, focusing on the thermodynamic properties of the intracluster medium on large scales. For azimuths not aligned with an infalling subcluster toward the southwest, our measured temperature and X-ray brightness profiles exhibit broadly consistent radial trends, with the temperature decreasing from about 8.5 keV at the cluster center to about 2 keV at a radius of 2 Mpc, which is the edge of our detection limit. The southwest merger significantly boosts the surface brightness, allowing us to detect X-ray emission out to {approx}2.2 Mpc along this direction. Apart from the southwestern infalling subcluster, the surface brightness profiles show multiple edges around radii of 30-40 arcmin. The azimuthally averaged temperature profile, as well as the deprojected density and pressure profiles, all show a sharp drop consistent with an outwardly-propagating shock front located at 40 arcmin, corresponding to the outermost edge of the giant radio halo observed at 352 MHz with the Westerbork Synthesis Radio Telescope. The shock front may be powering this radio emission. A clear entropy excess inside of r{sub 500} reflects the violent merging events linked with these morphological features. Beyond r{sub 500}, the entropy profiles of the Coma Cluster along the relatively relaxed directions are consistent with the power-law behavior expected from simple models of gravitational large-scale structure formation. The pressure is also in agreement at these radii with the expected values measured from Sunyaev-Zel'dovich data from the Planck satellite. However, due to the large uncertainties associated with the Coma Cluster measurements, we cannot yet exclude an entropy flattening in this system consistent with that seen in more relaxed cool core clusters.

Simionescu, A.; Werner, N.; Urban, O.; Allen, S. W. [KIPAC, Stanford University, 452 Lomita Mall, Stanford, CA 94305 (United States); Fabian, A. C.; Sanders, J. S.; Walker, S. A. [Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom); Mantz, A. [Kavli Institute for Cosmological Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Matsushita, K.; Sasaki, T.; Sato, T. [Department of Physics, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan); Nulsen, P. E. J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Takei, Y. [Institute of Space and Astronautical Science (ISAS), JAXA, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 Japan (Japan)

2013-09-20T23:59:59.000Z

362

SHARP THRESHOLDS FOR THE RANDOM-CLUSTER AND ISING MODELS  

E-Print Network [OSTI]

SHARP THRESHOLDS FOR THE RANDOM-CLUSTER AND ISING MODELS BENJAMIN GRAHAM AND GEOFFREY GRIMMETT. The models in question are the random-cluster model near the self-dual point psd(q) = q/(1 + q), the Ising in statistical physics, namely those of the random-cluster model and the Ising model. In each case, the event

Grimmett, Geoffrey

363

Towards Energy-Efficient Database Cluster Design Willis Lang  

E-Print Network [OSTI]

Towards Energy-Efficient Database Cluster Design Willis Lang University of Wisconsin wlang efficiency of DBMSs, none of these studies have looked at the architectural design space of energy-efficient parallel DBMS clusters. There are many challenges to increasing the energy efficiency of a DBMS cluster

Patel, Jignesh

364

VISCOSITY OF CONCENTRATED SUSPENSIONS: INFLUENCE OF CLUSTER FORMATION  

E-Print Network [OSTI]

1 VISCOSITY OF CONCENTRATED SUSPENSIONS: INFLUENCE OF CLUSTER FORMATION V.Starov1 , V.Zhdanov1 , M and these forces determine both structure and size of clusters. We assume that viscosity of concentrated suspension of viscosity on a concentration of dispersed particles taking into account cluster formation, is deduced. Under

Boyer, Edmond

365

A Hierarchical Checkpointing Protocol for Parallel Applications in Cluster Federations  

E-Print Network [OSTI]

A Hierarchical Checkpointing Protocol for Parallel Applications in Cluster Federations S federation. As a cluster federation comprises of a large number of nodes, there is a high probability fits to the characteristics of a cluster federation (large number of nodes, high latency and low

Paris-Sud XI, Université de

366

Rural Knowledge Clusters: Innovation and Vitality in America's Rural Communities  

E-Print Network [OSTI]

Rural Knowledge Clusters: Innovation and Vitality in America's Rural Communities Prepared for: U of Minnesota Rural Knowledge Clusters: Innovation and Vitality in America's Rural Communities Table of Contents Knowledge Clusters: Exploring The Role of Institutions in 9 Northwest Minnesota's Recreational Vehicle

Levinson, David M.

367

Supernova blast wave within a stellar cluster outflow  

Science Journals Connector (OSTI)

......the cluster wind velocity in units of...cluster, is the mass-loss rate...5pc, with mass-loss rate and wind velocities and v w...X-ray emission maps. APPENDIX...the radial velocity of the cluster wind, given in......

J. C. Rodríguez-Ramírez; A. C. Raga; P. F. Velázquez; A. Rodríguez-González; J. C. Toledo-Roy

2014-01-01T23:59:59.000Z

368

Sticking properties of water clusters Sebastien Zamith1,2  

E-Print Network [OSTI]

]. The pos- itively charged, protonated water clusters are produced in a gas aggregation source. Right afterSticking properties of water clusters S´ebastien Zamith1,2 , Pierre Feiden1,2 , Pierre Labastie1) Absolute attachment cross sections of single water molecules onto mass selected protonated water clusters

Paris-Sud XI, Université de

369

Photoelectron imaging of large anionic methanol clusters: ,,n70460...  

E-Print Network [OSTI]

been described elsewhere.9 Methanol cluster anions were produced by passing argon through a reservoirPhotoelectron imaging of large anionic methanol clusters: ,,MeOH...n - ,,n�70­460... Aster Kammrath Electron solvation in methanol anion clusters, MeOH n - n 70­460 , is studied by photoelectron imaging. Two

Neumark, Daniel M.

370

THE BURST CLUSTER: DARK MATTER IN A CLUSTER MERGER ASSOCIATED WITH THE SHORT GAMMA-RAY BURST, GRB 050509B  

E-Print Network [OSTI]

We have identified a merging galaxy cluster with evidence of two distinct subclusters. The X-ray and optical data suggest that the subclusters are presently moving away from each other after closest approach. This cluster ...

Dahle, H.

371

The Sustainability FYE Cluster The Sustainability FYE Cluster will make sustainable urban living a core experience for First  

E-Print Network [OSTI]

The Sustainability FYE Cluster The Sustainability FYE Cluster will make sustainable urban living University. The Sustainability community infuses the learning-living community with practical and theoretical approaches to sustainable living, merging students' living community with unique academic and field

372

Oxidation Behavior of CO Catalyzed by Several Decahedral Au Clusters: Role of Cluster Stability and Electric Field  

Science Journals Connector (OSTI)

Oxidation Behavior of CO Catalyzed by Several Decahedral Au Clusters: Role of Cluster Stability and Electric Field ... Key Laboratory of Automobile Materials, Ministry of Education, and School of Materials Science and Engineering, Jilin University, Changchun 130022, China ...

W. Liu; Y. F. Zhu; Q. Jiang

2010-11-15T23:59:59.000Z

373

LoCuSS: A COMPARISON OF CLUSTER MASS MEASUREMENTS FROM XMM-NEWTON AND SUBARU-TESTING DEVIATION FROM HYDROSTATIC EQUILIBRIUM AND NON-THERMAL PRESSURE SUPPORT  

SciTech Connect (OSTI)

We compare X-ray hydrostatic and weak-lensing mass estimates for a sample of 12 clusters that have been observed with both XMM-Newton and Subaru. At an over-density of DELTA = 500, we obtain 1 - M {sup X}/M {sup WL} = 0.01 +- 0.07 for the whole sample. We also divided the sample into undisturbed and disturbed sub-samples based on quantitative X-ray morphologies using asymmetry and fluctuation parameters, obtaining 1 - M {sup X}/M {sup WL} = 0.09 +- 0.06 and -0.06 +- 0.12 for the undisturbed and disturbed clusters, respectively. In addition to non-thermal pressure support, there may be a competing effect associated with adiabatic compression and/or shock heating which leads to overestimate of X-ray hydrostatic masses for disturbed clusters, for example, in the famous merging cluster A1914. Despite the modest statistical significance of the mass discrepancy, on average, in the undisturbed clusters, we detect a clear trend of improving agreement between M {sup X} and M {sup WL} as a function of increasing over-density, M{sup X}/M{sup WL}=(0.908+-0.004)+(0.187+-0.010){center_dot} log{sub 10}(DELTA/500). We also examine the gas mass fractions, f{sub gas} = M {sup gas}/M {sup WL}, finding that they are an increasing function of cluster radius, with no dependence on dynamical state, in agreement with predictions from numerical simulations. Overall, our results demonstrate that XMM-Newton and Subaru are a powerful combination for calibrating systematic uncertainties in cluster mass measurements.

Zhang, Yu-Ying [Argelander-Institut fuer Astronomie, Universitaet Bonn, Auf dem Huegel 71, 53121 Bonn (Germany); Okabe, Nobuhiro [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, 10617 Taipei, Taiwan (China); Finoguenov, Alexis [Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrasse, 85748 Garching (Germany); Smith, Graham P.; Sanderson, Alastair J. R. [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B152TT (United Kingdom); Piffaretti, Rocco [CEA, CEA-Saclay, 91191 Gif-sur-Yvette Cedex (France); Valdarnini, Riccardo [SISSA/ISAS, via Beirut 4, 34014 Trieste (Italy); Babul, Arif [Department of Physics and Astronomy, University of Victoria, 3800 Finnerty Road, Victoria, BC (Canada); Evrard, August E. [Department of Physics and Michigan Center for Theoretical Physics, University of Michigan, Ann Arbor, MI 48109 (United States); Mazzotta, Pasquale [Dipartimento di Fisica, Universita di Roma 'Tor Vergata', Via della Ricerca Scientifica 1, I-00133 Rome (Italy); Marrone, Daniel P., E-mail: yyzhang@astro.uni-bonn.d [Kavli Institute for Cosmological Physics, Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States)

2010-03-10T23:59:59.000Z

374

Carbon in Red Giants in Globular Clusters and Dwarf Spheroidal Galaxies  

E-Print Network [OSTI]

We present carbon abundances of red giants in Milky Way globular clusters and dwarf spheroidal galaxies (dSphs). Our sample includes measurements of carbon abundances for 154 giants in the clusters NGC 2419, M68, and M15 and 398 giants in the dSphs Sculptor, Fornax, Ursa Minor, and Draco. This sample doubles the number of dSph stars with measurements of [C/Fe]. The [C/Fe] ratio in the clusters decreases with increasing luminosity above log(L/L_sun) ~= 1.6, which can be explained by deep mixing in evolved giants. The same decrease is observed in dSphs, but the initial [C/Fe] of the dSph giants is not uniform. Stars in dSphs at lower metallicities have larger [C/Fe] ratios. We hypothesize that [C/Fe] (corrected to the initial carbon abundance) declines with increasing [Fe/H] due to the metallicity dependence of the carbon yield of asymptotic giant branch stars and due to the increasing importance of Type Ia supernovae at higher metallicities. We also identified 11 very carbon-rich giants (8 previously known) in...

Kirby, Evan N; Zhang, Andrew J; Deng, Michelle; Cohen, Judith G; Guhathakurta, Puragra; Shetrone, Matthew D; Lee, Young Sun; Rizzi, Luca

2015-01-01T23:59:59.000Z

375

Reaction of iron clusters with ammonia. I. Compositions of the ammoniated products and their implications for cluster structure  

SciTech Connect (OSTI)

Studies are described of the chemisorption of ammonia on isolated neutral iron clusters Fe/sub n/ for 2less than or equal tonless than or equal to165. Clusters are generated by laser vaporization in a continuous-flow-tube reactor, and reaction products are detected by laser-ionization time-of-flight mass spectrometry. Ammonia is found to chemisorb nondissociatively on cluster surfaces on the 1 ms time scale of these experiments. Measurements of ammonia uptake provide information on adsorption kinetics and on the number and nature of the binding sites. The ammonia binding energy is found to decrease with increasing cluster coverage. For chemically saturated clusters, the ratio of adsorbed NH/sub 3/ molecules to surface iron atoms is found to decrease with increasing cluster size, going from >1/3 for small clusters to <1/3 for n>100. Ammonia chemisorption is accompanied by a large decrease in cluster ionization potentials, as much as 2 eV for saturated clusters. At sufficiently high exposure the beginning of the formation of a second, physisorbed layer of molecules is seen. Detailed measurements of product composition under different exposure conditions give evidence for numerous changes in cluster structure throughout the growth sequence from small to large clusters. Often these structural changes involve particularly stable reaction products. Evidence for the existence of metastable structures is presented. Several possibilities for cluster structure are suggested.

Parks, E.K.; Nieman, G.C.; Pobo, L.G.; Riley, S.J.

1988-05-15T23:59:59.000Z

376

Intense emission of cluster anions from gold targets under impact of keV/u gold clusters.  

E-Print Network [OSTI]

Intense emission of cluster anions from gold targets under impact of keV/u gold clusters. M the emission yield of anionic clusters increases much faster with n than expected from simple proportionality. Accordingly, the most intense emission is observed for Au7 - : under Au9 + impact the Au7 - yield per incident

Boyer, Edmond

377

Quantum Metropolis Sampling  

E-Print Network [OSTI]

The original motivation to build a quantum computer came from Feynman who envisaged a machine capable of simulating generic quantum mechanical systems, a task that is believed to be intractable for classical computers. Such a machine would have a wide range of applications in the simulation of many-body quantum physics, including condensed matter physics, chemistry, and high energy physics. Part of Feynman's challenge was met by Lloyd who showed how to approximately decompose the time-evolution operator of interacting quantum particles into a short sequence of elementary gates, suitable for operation on a quantum computer. However, this left open the problem of how to simulate the equilibrium and static properties of quantum systems. This requires the preparation of ground and Gibbs states on a quantum computer. For classical systems, this problem is solved by the ubiquitous Metropolis algorithm, a method that basically acquired a monopoly for the simulation of interacting particles. Here, we demonstrate how to implement a quantum version of the Metropolis algorithm on a quantum computer. This algorithm permits to sample directly from the eigenstates of the Hamiltonian and thus evades the sign problem present in classical simulations. A small scale implementation of this algorithm can already be achieved with today's technology

K. Temme; T. J. Osborne; K. G. Vollbrecht; D. Poulin; F. Verstraete

2009-11-18T23:59:59.000Z

378

The APM Galaxy Survey:- V. Catalogues of Galaxy Clusters  

E-Print Network [OSTI]

We describe the construction of catalogues of galaxy clusters from the APM Galaxy survey using an automated algorithm based on Abell-like selection criteria. We investigate the effects of varying several parameters in our selection algorithm, including the magnitude range, and radius from the cluster centre used to estimate the cluster richnesses. We quantify the accuracy of the photometric distance estimates by comparing with measured redshifts, and we investigate the stability and completeness of the resulting catalogues. We find that the angular correlation functions for different cluster catalogues are in good agreement with one another, and are also consistent with the observed amplitude of the spatial correlation function of rich clusters.

Gavin Dalton; Steve Maddox; Will Sutherland; George Efstathiou

1997-01-23T23:59:59.000Z

379

Characterizing cluster morphology using vector-valued Minkowski functionals  

E-Print Network [OSTI]

The morphology of galaxy clusters is quantified using Minkowski functionals, especially the vector-valued ones, which contain directional information and are related to curvature centroids. The asymmetry of clusters and the amount of their substructure can be characterized in a unique way using these measures. -- We briefly introduce vector-valued Minkowski functionals (also known as Querma\\ss vectors) and suggest their application to cluster data in terms of a morphological characterization of excursion sets. Furthermore, we develop robust structure functions which describe the dynamical state of a cluster and study the evolution of clusters using numerical simulations.

Claus Beisbart; Thomas Buchert

1997-11-04T23:59:59.000Z

380

CONSTRAINTS ON DARK MATTER ANNIHILATION IN CLUSTERS OF GALAXIES FROM DIFFUSE RADIO EMISSION  

SciTech Connect (OSTI)

Annihilation of dark matter can result in the production of stable Standard Model particles including electrons and positrons that, in the presence of magnetic fields, lose energy via synchrotron radiation, observable as radio emission. Galaxy clusters are excellent targets to search for or to constrain the rate of dark matter annihilation, as they are both massive and dark matter dominated. In this study, we place limits on dark matter annihilation in a sample of nearby clusters using upper limits on the diffuse radio emission, low levels of observed diffuse emission, or detections of radio mini-halos. We find that the strongest limits on the annihilation cross section are better than limits derived from the non-detection of clusters in the gamma-ray band by a factor of {approx}3 or more when the same annihilation channel and substructure model, but different best-case clusters, are compared. The limits on the cross section depend on the assumed amount of substructure, varying by as much as two orders of magnitude for increasingly optimistic substructure models as compared to a smooth Navarro-Frenk-White profile. In our most optimistic case, using the results of the Phoenix Project, we find that the derived limits reach below the thermal relic cross section of 3 Multiplication-Sign 10{sup -26} cm{sup 3} s{sup -1} for dark matter masses as large as 400 GeV, for the b b-bar annihilation channel. We discuss uncertainties due to the limited available data on the magnetic field structure of individual clusters. We also report the discovery of diffuse radio emission from the central 30-40 kpc regions of the groups M49 and NGC 4636.

Storm, Emma; Jeltema, Tesla E.; Profumo, Stefano [Department of Physics, University of California, 1156 High St., Santa Cruz, CA 95064 (United States); Rudnick, Lawrence [Minnesota Institute for Astrophysics, School of Physics and Astronomy, University of Minnesota, 116 Church Street SE, Minneapolis, MN 55455 (United States)

2013-05-10T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

The Voronoi Tessellation Cluster Finder in 2 1 Dimensions  

SciTech Connect (OSTI)

We present a detailed description of the Voronoi Tessellation (VT) cluster finder algorithm in 2+1 dimensions, which improves on past implementations of this technique. The need for cluster finder algorithms able to produce reliable cluster catalogs up to redshift 1 or beyond and down to 10{sup 13.5} solar masses is paramount especially in light of upcoming surveys aiming at cosmological constraints from galaxy cluster number counts. We build the VT in photometric redshift shells and use the two-point correlation function of the galaxies in the field to both determine the density threshold for detection of cluster candidates and to establish their significance. This allows us to detect clusters in a self-consistent way without any assumptions about their astrophysical properties. We apply the VT to mock catalogs which extend to redshift 1.4 reproducing the ?CDM cosmology and the clustering properties observed in the Sloan Digital Sky Survey data. An objective estimate of the cluster selection function in terms of the completeness and purity as a function of mass and redshift is as important as having a reliable cluster finder. We measure these quantities by matching the VT cluster catalog with the mock truth table. We show that the VT can produce a cluster catalog with completeness and purity >80% for the redshift range up to {approx}1 and mass range down to {approx}10{sup 13.5} solar masses.

Soares-Santos, Marcelle; /Fermilab /Sao Paulo U.; de Carvalho, Reinaldo R.; /Sao Jose, INPE; Annis, James; /Fermilab; Gal, Roy R.; /Hawaii U.; La Barbera, Francesco; /Capodimonte Observ.; Lopes, Paulo A.A.; /Valongo Observ.; Wechsler, Risa H.; Busha, Michael T.; Gerke, Brian F.; /SLAC /KIPAC, Menlo Park

2011-06-23T23:59:59.000Z

382

Landscape Characterization and Representativeness Analysis for Understanding Sampling Network Coverage  

SciTech Connect (OSTI)

Sampling networks rarely conform to spatial and temporal ideals, often comprised of network sampling points which are unevenly distributed and located in less than ideal locations due to access constraints, budget limitations, or political conflict. Quantifying the global, regional, and temporal representativeness of these networks by quantifying the coverage of network infrastructure highlights the capabilities and limitations of the data collected, facilitates upscaling and downscaling for modeling purposes, and improves the planning efforts for future infrastructure investment under current conditions and future modeled scenarios. The work presented here utilizes multivariate spatiotemporal clustering analysis and representativeness analysis for quantitative landscape characterization and assessment of the Fluxnet, RAINFOR, and ForestGEO networks. Results include ecoregions that highlight patterns of bioclimatic, topographic, and edaphic variables and quantitative representativeness maps of individual and combined networks.

Maddalena, Damian; Hoffman, Forrest; Kumar, Jitendra; Hargrove, William

2014-08-01T23:59:59.000Z

383

Landscape Characterization and Representativeness Analysis for Understanding Sampling Network Coverage  

DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

Sampling networks rarely conform to spatial and temporal ideals, often comprised of network sampling points which are unevenly distributed and located in less than ideal locations due to access constraints, budget limitations, or political conflict. Quantifying the global, regional, and temporal representativeness of these networks by quantifying the coverage of network infrastructure highlights the capabilities and limitations of the data collected, facilitates upscaling and downscaling for modeling purposes, and improves the planning efforts for future infrastructure investment under current conditions and future modeled scenarios. The work presented here utilizes multivariate spatiotemporal clustering analysis and representativeness analysis for quantitative landscape characterization and assessment of the Fluxnet, RAINFOR, and ForestGEO networks. Results include ecoregions that highlight patterns of bioclimatic, topographic, and edaphic variables and quantitative representativeness maps of individual and combined networks.

Maddalena, Damian; Hoffman, Forrest; Kumar, Jitendra; Hargrove, William

384

LoCuSS: THE MASS DENSITY PROFILE OF MASSIVE GALAXY CLUSTERS AT z = 0.2 {sup ,}  

SciTech Connect (OSTI)

We present a stacked weak-lensing analysis of an approximately mass-selected sample of 50 galaxy clusters at 0.15 < z < 0.3, based on observations with Suprime-Cam on the Subaru Telescope. We develop a new method for selecting lensed background galaxies from which we estimate that our sample of red background galaxies suffers just 1% contamination. We detect the stacked tangential shear signal from the full sample of 50 clusters, based on this red sample of background galaxies, at a total signal-to-noise ratio of 32.7. The Navarro-Frenk-White model is an excellent fit to the data, yielding sub-10% statistical precision on mass and concentration: M{sub vir}=7.19{sup +0.53}{sub -0.50} Multiplication-Sign 10{sup 14} h{sup -1} M{sub sun}, c{sub vir}=5.41{sup +0.49}{sub -0.45} (c{sub 200}=4.22{sup +0.40}{sub -0.36}). Tests of a range of possible systematic errors, including shear calibration and stacking-related issues, indicate that they are subdominant to the statistical errors. The concentration parameter obtained from stacking our approximately mass-selected cluster sample is broadly in line with theoretical predictions. Moreover, the uncertainty on our measurement is comparable with the differences between the different predictions in the literature. Overall, our results highlight the potential for stacked weak-lensing methods to probe the mean mass density profile of cluster-scale dark matter halos with upcoming surveys, including Hyper-Suprime-Cam, Dark Energy Survey, and KIDS.

Okabe, Nobuhiro; Umetsu, Keiichi [Academia Sinica Institute of Astronomy and Astrophysics (ASIAA), P. O. Box 23-141, Taipei 10617, Taiwan (China); Smith, Graham P. [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Takada, Masahiro [Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU, WPI), University of Tokyo, Chiba 277-8582 (Japan); Futamase, Toshifumi, E-mail: okabe@asiaa.sinica.edu.tw, E-mail: gps@star.sr.bham.ac.uk [Astronomical Institute, Tohoku University, Aramaki, Aoba-ku, Sendai 980-8578 (Japan)

2013-06-01T23:59:59.000Z

385

Clustering Segregation With UV Luminosity in Lyman-Break Galaxies at z~3 and Its Implications  

E-Print Network [OSTI]

We report on the clustering properties of Lyman-break galaxies (LBGs) at z~3. The correlation length of flux-limited samples of LBGs depends on their rest-frame ultraviolet (UV) luminosity at lambda ~1700 Angstrom, with fainter galaxies being less strongly clustered in space. It decreases by a factor ~3 over the range of limiting magnitudes that we have probed, namely 25samples include galaxies with smaller mass. We find that: 1) the clustering strength of LBGs follows, within the errors, the same scaling law with the volume density predicted for cold dark matter (CDM) halos; 2) the scaling law predicted for the galaxies using the halos mass spectrum and a number of models for the relationship that maps the halos' mass into the galaxies' UV luminosity depends only on how tightly mass and UV luminosity correlate, but is otherwise insensitive to the details of the models. These results provide additional evidence that the strong spatial clustering of LBGs is due to galaxy biasing, supporting biased galaxy formation and gravitational instability as the primary mechanism for the formation of structure. We also find that 1) a scale invariant relationship between mass and UV luminosity (e.g. a power law) is not supported, suggesting that the properties of star formation of galaxies change along the mass spectrum of the observed LBGs; 2) the scatter of the UV luminosity of LBGs of given mass must be relatively small for massive LBGs, suggesting that the mass is an important parameter in regulating the activity of star formation in these systems, and that the fraction of massive halos at z~3 that are not observed in UV-selected surveys is not large.

Mauro Giavalisco; Mark Dickinson

2000-12-12T23:59:59.000Z

386

Sample Environment | ORNL Neutron Sciences  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Home › Instruments › SNS › Sample Environment Home › Instruments › SNS › Sample Environment Sample Environment The Sample Environment Group provides equipment and support for studying materials under controlled conditions (temperature, pressure, magnetic field, chemical environment, etc.). When you come to SNS to conduct an experiment, our front-line teams are there to support you. Although we currently offer a wide range of capabilities, we realize that these capabilities must continually grow. Therefore, we also have a busy research and development team, and we encourage you to partner with them to develop new equipment and techniques. The Sample Environment Equipment Database allows you to search for information about the sample environment equipment available for HFIR and SNS instruments. It will be available in the near future for SNS sample

387

Rock Sampling | Open Energy Information  

Open Energy Info (EERE)

Rock Sampling Rock Sampling Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Rock Sampling Details Activities (13) Areas (13) Regions (1) NEPA(0) Exploration Technique Information Exploration Group: Field Techniques Exploration Sub Group: Field Sampling Parent Exploration Technique: Field Sampling Information Provided by Technique Lithology: Rock samples are used to define lithology. Field and lab analyses can be used to measure the chemical and isotopic constituents of rock samples. Stratigraphic/Structural: Provides information about the time and environment which formed a particular geologic unit. Microscopic rock textures can be used to estimate the history of stress and strain, and/or faulting. Hydrological: Isotope geochemistry can reveal fluid circulation of a geothermal system.

388

Soil Sampling | Open Energy Information  

Open Energy Info (EERE)

Soil Sampling Soil Sampling Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Soil Sampling Details Activities (10) Areas (9) Regions (1) NEPA(0) Exploration Technique Information Exploration Group: Field Techniques Exploration Sub Group: Field Sampling Parent Exploration Technique: Field Sampling Information Provided by Technique Lithology: Stratigraphic/Structural: Can reveal relatively high permeability zones Hydrological: Thermal: Used to locate active hydrothermal systems Dictionary.png Soil Sampling: Soil sampling is a method that can be used for exploration of geothermal resources that lack obvious surface manifestations. Soils that are above or adjacent to a "hidden" hydrothermal system will have a unique chemistry that can be indicative of a hydrothermal system at depth and a zone of

389

Visualization Clusters | Argonne Leadership Computing Facility  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Eureka Eureka Analytics and Visualization Visualization Clusters Tukey Tukey is the ALCF's newest analysis and visualization cluster. Equipped with state-of-the-art graphics processing units (GPUs), Tukey converts computational data from Mira into high-resolution visual representations. The resulting images, videos, and animations help users to better analyze and understand the data generated by Mira. Tukey can also be used for statistical analysis, helping to pinpoint trends in the simulation data. Additionally, the system is capable of preprocessing efforts, such as meshing, to assist users preparing for Mira simulations. Tukey shares the Mira network and parallel file system, enabling direct access to Mira-generated results. Configuration Two 2 GHz 8-core AMD Opteron CPUs per node

390

The Georgi Algorithms of Jet Clustering  

E-Print Network [OSTI]

We reveal the direct link between the jet clustering algorithms recently proposed by Howard Georgi and parton shower kinematics, providing sound support from the theoretical side. The kinematics of this class of elegant algorithms is explored systematically and the jet function is generalized to $J^{(n)}_\\beta$ with a jet function index $n$. Based on three basic requirements that the result of jet clustering is process-independent, for softer subjets the inclusion cone is larger, and that the cone size cannot be too large in order to avoid mixing different jets, we derive constraints on the jet function index $n$ and the jet function parameter $\\beta$ which are closely related to phase space boundaries. Finally, we demonstrate that the jet algorithm is boost invariant.

Shao-Feng Ge

2014-08-30T23:59:59.000Z

391

Cluster perturbation theory for Hubbard models  

Science Journals Connector (OSTI)

Cluster perturbation theory is a technique for calculating the spectral weight of Hubbard models of strongly correlated electrons, which combines exact diagonalizations on small clusters with strong-coupling perturbation theory at leading order. It is exact in both the strong- and weak-coupling limits and provides a good approximation to the spectral function at any wave vector. Following the paper by Sénéchal et al. [Phys. Rev. Lett. 84, 522 (2000)], we provide a more complete description and derivation of the method. We illustrate some of its capabilities, in particular regarding the effect of doping, the calculation of ground state energy and double occupancy, the disappearance of the Fermi surface in the t-t? Hubbard model, and so on. The method is applicable to any model with on-site repulsion only.

David Sénéchal; Danny Perez; Dany Plouffe

2002-08-30T23:59:59.000Z

392

WIYN Open Cluster Study 1: Deep Photometry of NGC 188  

E-Print Network [OSTI]

We have employed precise V and I photometry of NGC 188 at WIYN to explore the cluster luminosity function (LF) and study the cluster white dwarfs (WDs). Our photometry is offset by V = 0.052 (fainter) from Sandage (1962) and Eggen & Sandage (1969). All published photometry for the past three decades have been based on these two calibrations, which are in error by 0.05 +- 0.01. We employ the Pinsonneault etal (1998) fiducial main sequence to derive a cluster distance modulus of 11.43 +- 0.08. We report observations that are >= 50% complete to V = 24.6 and find that the cluster central-field LF peaks at M_I ~ 3 to 4. This is unlike the solar neighborhood LF and unlike the LFs of dynamically unevolved portions of open and globular clusters, which rise continuously until M_I ~ 9.5. Although we find that >= 50% of the unresolved cluster objects are multiple systems, their presence cannot account for the shape of the NGC 188 LF. For theoretical reasons (Terlevich 1987; Vesperini & Heggie 1997) having to do with the survivability of NGC 188 we believe the cluster is highly dynamically evolved and that the missing low luminosity stars are either in the cluster outskirts or have left the cluster altogether. We identify nine candidate WDs, of which we expect three to six are bona fide cluster WDs. The luminosities of the faintest likely WD indicates an age (Bergeron, Wesemael, & Beauchamp 1995) of 1.14 +- 0.09 Gyrs. This is a lower limit to the cluster age and observations probing to V = 27 or 28 will be necessary to find the faintest cluster WDs and independently determine the cluster age. While our age limit is not surprising for this ~6 Gyr old cluster, our result demonstrates the value of the WD age technique with its very low internal errors. (abridged)

Ted von Hippel; Ata Sarajedini

1998-06-06T23:59:59.000Z

393

The Metallicity Dependence of the Stellar Luminosity and Initial Mass Functions: HST Observations of Open and Globular Clusters  

E-Print Network [OSTI]

Using HST and the WFPC2 we have acquired very deep V- and I-band photometry of stars in NGC 2420 and NGC 2477 to study cluster luminosity functions at approximately solar metallicity. We have determined these cluster luminosity functions down to $M_I$ = 10.5 (0.2 M$_{\\odot}$) and find that the luminosity function of NGC 2420 turns over at $M_I$ $\\approx$ 9.0, and possibly stops altogether by $M_I$ $\\approx$ 9.5. The luminosity function of NGC 2477 may flatten at $M_I$ $\\geq$ 9.5. We compare our open cluster luminosity functions to the solar neighborhood field star luminosity function of Kroupa, Tout \\& Gilmore (1993) and the four published HST globular cluster luminosity functions: $\\omega$ Cen (Elson {\\it et al.}\\ 1995), 47 Tuc (De Marchi \\& Paresce 1995b), M 15 (De Marchi \\& Paresce 1995a), and NGC 6397 (Paresce, De Marchi \\& Romaniello 1995). We find a smooth relation between the location of the luminosity function turn-over and the metallicity for all these low mass star samples which matches the expected $M_I$ versus [Fe/H] trend for a model star of $\\approx$ 0.27 M$_{\\odot}$ (Saumon 1995; Alexander {\\it et al.}\\ 1996). We interpret this smooth and systematic behavior in the cluster luminosity functions as strong evidence in favor of an invariant initial mass function and a metallicity-dependent mass-luminosity relation.

Ted von Hippel; Gerard Gilmore; Nial Tanvir; David Robinson; Derek H. P. Jones

1996-05-02T23:59:59.000Z

394

Cluster Formation in Contracting Molecular Clouds  

E-Print Network [OSTI]

We explore, through a simplified, semi-analytic model, the formation of dense clusters containing massive stars. The parent cloud spawning the cluster is represented as an isothermal sphere. This sphere is in near force balance between self-gravity and turbulent pressure. Self-gravity, mediated by turbulent dissipation, drives slow contraction of the cloud, eventually leading to a sharp central spike in density and the onset of dynamical instability. We suggest that, in a real cloud, this transition marks the late and rapid production of massive stars. We also offer an empirical prescription, akin to the Schmidt law, for low-mass star formation in our contracting cloud. Applying this prescription to the Orion Nebula Cluster, we are able to reproduce the accelerating star formation previously inferred from the distribution of member stars in the HR diagram. The cloud turns about 10 percent of its mass into low-mass stars before becoming dynamically unstable. Over a cloud free-fall time, this figure drops to 1 percent, consistent with the overall star formation efficiency of molecular clouds in the Galaxy.

Eric Huff; Steven Stahler

2007-08-07T23:59:59.000Z

395

Oxygen abundance of open cluster dwarfs  

E-Print Network [OSTI]

We present oxygen abundances of dwarfs in the young open cluster IC 4665 deduced from the OI $\\lambda$7774 triplet lines and of dwarfs in the open cluster Pleiades derived from the [OI] $\\lambda$6300 forbidden line. Stellar parameters and oxygen abundances were derived using the spectroscopic synthesis tool SME (Spectroscopy Made Easy). We find a dramatic increase in the upper boundary of the OI triplet abundances with decreasing temperature in the dwarfs of IC 4665, consistent with the trend found by Schuler et al. in the open clusters Pleiades and M 34, and to a less extent in the cool dwarfs of Hyades (Schuler et al. 2006a) and UMa (King & Schuler 2005). By contrast, oxygen abundances derived from the [OI] $\\lambda$6300 forbidden line for stars in Pleiades and Hyades (Schuler et al. 2006b) are constant within the errors. Possible mechanisms that may lead a varying oxygen triplet line abundance are examined, including systematic errors in the stellar parameter determinations, the NLTE effects, surface activities and granulation. The age-related effects stellar surface activities (especially the chromospheric activities) are suggested by our analysis to blame for the large spreads of oxygen triplet line abundances.

Z. -X. Shen; X. -W. Liu; H. -W. Zhang; B. Jones; D. N. C. Lin

2007-03-30T23:59:59.000Z

396

MEASURING THE MASS DISTRIBUTION IN GALAXY CLUSTERS  

SciTech Connect (OSTI)

Cluster mass profiles are tests of models of structure formation. Only two current observational methods of determining the mass profile, gravitational lensing, and the caustic technique are independent of the assumption of dynamical equilibrium. Both techniques enable the determination of the extended mass profile at radii beyond the virial radius. For 19 clusters, we compare the mass profile based on the caustic technique with weak lensing measurements taken from the literature. This comparison offers a test of systematic issues in both techniques. Around the virial radius, the two methods of mass estimation agree to within {approx}30%, consistent with the expected errors in the individual techniques. At small radii, the caustic technique overestimates the mass as expected from numerical simulations. The ratio between the lensing profile and the caustic mass profile at these radii suggests that the weak lensing profiles are a good representation of the true mass profile. At radii larger than the virial radius, the extrapolated Navarro, Frenk and White fit to the lensing mass profile exceeds the caustic mass profile. Contamination of the lensing profile by unrelated structures within the lensing kernel may be an issue in some cases; we highlight the clusters MS0906+11 and A750, superposed along the line of sight, to illustrate the potential seriousness of contamination of the weak lensing signal by these unrelated structures.

Geller, Margaret J. [Smithsonian Astrophysical Observatory, 60 Garden St., Cambridge, MA 02138 (United States)] [Smithsonian Astrophysical Observatory, 60 Garden St., Cambridge, MA 02138 (United States); Diaferio, Antonaldo [Dipartimento di Fisica, Universita degli Studi di Torino, via P. Giuria 1, I-10125 Torino (Italy)] [Dipartimento di Fisica, Universita degli Studi di Torino, via P. Giuria 1, I-10125 Torino (Italy); Rines, Kenneth J. [Department of Physics and Astronomy, Western Washington University, Bellingham, WA 98225 (United States)] [Department of Physics and Astronomy, Western Washington University, Bellingham, WA 98225 (United States); Serra, Ana Laura, E-mail: mgeller@cfa.harvard.edu, E-mail: diaferio@ph.unito.it, E-mail: kenneth.rines@wwu.edu, E-mail: serra@to.infn.it [INAF, Osservatorio Astronomico di Torino, via Osservatorio 20, I-10025 Pino Torinese (Italy)

2013-02-10T23:59:59.000Z

397

Robustness of cluster synchronous patterns in small-world networks with inter-cluster co-competition balance  

SciTech Connect (OSTI)

All edges in the classical Watts and Strogatz's small-world network model are unweighted and cooperative (positive). By introducing competitive (negative) inter-cluster edges and assigning edge weights to mimic more realistic networks, this paper develops a modified model which possesses co-competitive weighted couplings and cluster structures while maintaining the common small-world network properties of small average shortest path lengths and large clustering coefficients. Based on theoretical analysis, it is proved that the new model with inter-cluster co-competition balance has an important dynamical property of robust cluster synchronous pattern formation. More precisely, clusters will neither merge nor split regardless of adding or deleting nodes and edges, under the condition of inter-cluster co-competition balance. Numerical simulations demonstrate the robustness of the model against the increase of the coupling strength and several topological variations.

Zhang, Jianbao [School of Science, Hangzhou Dianzi University, Hangzhou 310018 (China)] [School of Science, Hangzhou Dianzi University, Hangzhou 310018 (China); Ma, Zhongjun, E-mail: mzj1234402@163.com [School of Mathematics and Computing Science, Guilin University of Electronic Technology, Guilin 541004 (China)] [School of Mathematics and Computing Science, Guilin University of Electronic Technology, Guilin 541004 (China); Chen, Guanrong [Department of Electronic Engineering, City University of Hong Kong, Kowloon, Hong Kong (China)] [Department of Electronic Engineering, City University of Hong Kong, Kowloon, Hong Kong (China)

2014-06-15T23:59:59.000Z

398

Tracking Cluster Debris (TraCD) I: dissolution of clusters and searching the Solar cradle  

E-Print Network [OSTI]

Here we focus on the dynamical aspect and given that most of the stars in the Milky Way have been born in stellar associations or clusters that have lived a few Myr up to several Gyr, we focus on the evolution of star clusters. We have carried out our simulations in two steps: 1) we have created a Galactic disc dynamically as close to observations as possible and 2) we have evolved three sets of stellar clusters with masses of 400, 1000 and 15000 Msun to dissolution. The birth location of these sets was 4, 6, 8 and 10 kpc for the 400 and 1000 Msun clusters and 4, 6, 8, 10 and 12 kpc for the 15000 Msun. We have focussed our efforts on studying the state of these escapers after 4.5 Gyr of evolution in the Solar annulus, i.e. 7.5 Solar orbit. We found by using dynamical arguments that for our 400 Msun clusters there is a 49 per cent higher chance of the Su...

Loyola, Guido R I Moyano; Hurley, Jarrod R; Gibson, Brad K

2014-01-01T23:59:59.000Z

399

LoCuSS: THE STEADY DECLINE AND SLOW QUENCHING OF STAR FORMATION IN CLUSTER GALAXIES OVER THE LAST FOUR BILLION YEARS  

SciTech Connect (OSTI)

We present an analysis of the levels and evolution of star formation activity in a representative sample of 30 massive galaxy clusters at 0.15 < z < 0.30 from the Local Cluster Substructure Survey, combining wide-field Spitzer/MIPS 24 ?m data with extensive spectroscopy of cluster members. The specific SFRs of massive (M > or approx. 10{sup 10} M{sub ?}) star-forming cluster galaxies within r{sub 200} are found to be systematically ?28% lower than their counterparts in the field at fixed stellar mass and redshift, a difference significant at the 8.7? level. This is the unambiguous signature of star formation in most (and possibly all) massive star-forming galaxies being slowly quenched upon accretion into massive clusters, their star formation rates (SFRs) declining exponentially on quenching timescales in the range 0.7-2.0 Gyr. We measure the mid-infrared Butcher-Oemler effect over the redshift range 0.0-0.4, finding rapid evolution in the fraction (f{sub SF}) of massive (M{sub K} < – 23.1) cluster galaxies within r{sub 200} with SFRs > 3 M{sub ?} yr{sup –1}, of the form f{sub SF}?(1 + z){sup 7.6±1.1}. We dissect the origins of the Butcher-Oemler effect, revealing it to be due to the combination of a ?3 × decline in the mean specific SFRs of star-forming cluster galaxies since z ? 0.3 with a ?1.5 × decrease in number density. Two-thirds of this reduction in the specific SFRs of star-forming cluster galaxies is due to the steady cosmic decline in the specific SFRs among those field galaxies accreted into the clusters. The remaining one-third reflects an accelerated decline in the star formation activity of galaxies within clusters. The slow quenching of star formation in cluster galaxies is consistent with a gradual shut down of star formation in infalling spiral galaxies as they interact with the intracluster medium via ram-pressure stripping or starvation mechanisms. The observed sharp decline in star formation activity among cluster galaxies since z ? 0.4 likely reflects the increased susceptibility of low-redshift spiral galaxies to gas removal mechanisms as their gas surface densities decrease with time. We find no evidence for the build-up of cluster S0 bulges via major nuclear starburst episodes.

Haines, C. P.; Pereira, M. J.; Egami, E.; Rawle, T. D. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Smith, G. P.; Sanderson, A. J. R. [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Babul, A. [Department of Physics and Astronomy, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 1A1 (Canada); Finoguenov, A. [Department of Physics, University of Helsinki, Gustaf Hällströmin katu 2a, FI-0014 Helsinki (Finland); Merluzzi, P.; Busarello, G. [INAF-Osservatorio Astronomico di Capodimonte, via Moiariello 16, I-80131 Napoli (Italy); Okabe, N., E-mail: cphaines@as.arizona.edu [Academia Sinica Institute of Astronomy and Astrophysics (ASIAA), P.O. Box 23-141, Taipei 10617, Taiwan (China)

2013-10-01T23:59:59.000Z

400

Theoretical investigations of silver clusters and silver-ligand systems.  

SciTech Connect (OSTI)

Studies directed at understanding structural and electronic properties of silver clusters have been and remain the subject of an active theoretical [1-22] and experimental [23- 38] effort. One of the reasons is the (still) important role these systems play in the photographic process. Investigations of interactions of silver clusters with different atoms and molecules are motivated primarily by a possible utility of these clusters in catalytic processes. The important role of silver in the selective oxidation of ethylene into ethylene oxide, the feedstock for polyester production, is well-known [39]. Possible variations in chemical reactivity with the cluster size and understanding of the mechanisms of interactions with different ligands may lead to new and more efficient applications. Investigations of cluster-ligand systems also contribute a great deal to a better understanding of gas-surface interactions. Accordingly, theoretical studies of silver clusters and cluster-ligand systems [40-44] fall into two categories--those that use clusters as models for silver surfaces [40], and those that target clusters and cluster-ligand interactions as subjects in their own right [41-44]. The common goal of all these studies is to elucidate the nature of the interatomic interactions and bonding at the microscopic level and thereby arrive at a fundamental understanding and description of the various structural and electronic properties.

Jellinek, J.; Salian, U.; Srinivas, S.

1999-05-19T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

MOCK OBSERVATIONS OF BLUE STRAGGLERS IN GLOBULAR CLUSTER MODELS  

SciTech Connect (OSTI)

We created artificial color-magnitude diagrams of Monte Carlo dynamical models of globular clusters and then used observational methods to determine the number of blue stragglers in those clusters. We compared these blue stragglers to various cluster properties, mimicking work that has been done for blue stragglers in Milky Way globular clusters to determine the dominant formation mechanism(s) of this unusual stellar population. We find that a mass-based prescription for selecting blue stragglers will select approximately twice as many blue stragglers than a selection criterion that was developed for observations of real clusters. However, the two numbers of blue stragglers are well-correlated, so either selection criterion can be used to characterize the blue straggler population of a cluster. We confirm previous results that the simplified prescription for the evolution of a collision or merger product in the BSE code overestimates their lifetimes. We show that our model blue stragglers follow similar trends with cluster properties (core mass, binary fraction, total mass, collision rate) as the true Milky Way blue stragglers as long as we restrict ourselves to model clusters with an initial binary fraction higher than 5%. We also show that, in contrast to earlier work, the number of blue stragglers in the cluster core does have a weak dependence on the collisional parameter ? in both our models and in Milky Way globular clusters.

Sills, Alison; Glebbeek, Evert [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1 (Canada); Chatterjee, Sourav [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States); Rasio, Frederic A., E-mail: asills@mcmaster.ca, E-mail: e.glebbeek@astro.ru.nl, E-mail: s.chatterjee@astro.ufl.edu, E-mail: rasio@northwestern.edu [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States)

2013-11-10T23:59:59.000Z

402

Sample page | Open Energy Information  

Open Energy Info (EERE)

Sample page Sample page Jump to: navigation, search This page has been rated 13[1][2] on the scale of awesomness. This page is awesome! The above text is generated by the SampleTemplate. Try editing it and changing the level of awesomeness to see the template react. Hint: It says something different depending on whether or not the page is at least 5 awesome. This page is related to the following topics[3][4]: References Sample pages Help pages Additional Info Name Sample page Awesomeness 13 Topics (raw) References; Sample pages; Help pages; References ↑ Francis C. Monastero. 2002. An overview of industry-military cooperation in the development of power operations at the Coso geothermal field in southern California. GRC Bulletin. . ↑ EPRI. 12/12/2012. Assessment and Mapping of the Riverine

403

Adaptive Sampling for Environmental Robotics  

E-Print Network [OSTI]

186, 2003. S. Thrun, “Robotics Mapping: A survey”, Exploringtechnique to environmental robotics applications includingSampling for Environmental Robotics Mohammad Rahimi †,‡‡ ,

Mohammad Rahimi; Richard Pon; Deborah Estrin; William J. Kaiser; Mani Srivastava; Gaurav S. Sukhatme

2003-01-01T23:59:59.000Z

404

Sample Residential Program Term Sheet  

Broader source: Energy.gov [DOE]

A sample for defining and elaborating on the specifics of a clean energy loan program. Author: U.S. Department of Energy

405

ccsd-00001265(version1):10Mar2004 Applied Physics A (2004) accepted Silicon clusters produced by femtosecond laser ablation: Non-thermal emission and  

E-Print Network [OSTI]

by femtosecond laser ablation: Non-thermal emission and gas-phase condensation Alexander V. Bulgakov Institute mechanisms of cluster formation (Coulomb explosion, gas-phase condensation, phase explosion) are discussed sampled parallel to the plume axis by a 500 V repeller pulse at a time delay td in respect to the laser

Boyer, Edmond

406

Investigation of the Platinum Cluster Size and Location on Zeolite KL with 129Xe NMR, XAFS, and Xenon Adsorption  

Science Journals Connector (OSTI)

Investigation of the Platinum Cluster Size and Location on Zeolite KL with 129Xe NMR, XAFS, and Xenon Adsorption ... Figure 4 k3?(k)-weighted EXAFS oscillation for Pt/KL samples and the Fourier transform in r-space:? (a,d) 2.0 wt % Pt/KL; (b,e) 3.4 wt % Pt/KL; (c,f) 5.2 wt % Pt/KL. ...

Sung June Cho; Wha-Seung Ahn; Suk Bong Hong; Ryong Ryoo

1996-03-21T23:59:59.000Z

407

MEASURING THE ULTIMATE HALO MASS OF GALAXY CLUSTERS: REDSHIFTS AND MASS PROFILES FROM THE HECTOSPEC CLUSTER SURVEY (HeCS)  

SciTech Connect (OSTI)

The infall regions of galaxy clusters represent the largest gravitationally bound structures in a {Lambda}CDM universe. Measuring cluster mass profiles into the infall regions provides an estimate of the ultimate mass of these halos. We use the caustic technique to measure cluster mass profiles from galaxy redshifts obtained with the Hectospec Cluster Survey (HeCS), an extensive spectroscopic survey of galaxy clusters with MMT/Hectospec. We survey 58 clusters selected by X-ray flux at 0.1 < z < 0.3. The survey includes 22,680 unique MMT/Hectospec redshifts for individual galaxies; 10,145 of these galaxies are cluster members. For each cluster, we acquired high signal-to-noise spectra for {approx}200 cluster members and a comparable number of foreground/background galaxies. The cluster members trace out infall patterns around the clusters. The members define a very narrow red sequence. We demonstrate that the determination of velocity dispersion is insensitive to the inclusion of bluer members (a small fraction of the cluster population). We apply the caustic technique to define membership and estimate the mass profiles to large radii. The ultimate halo mass of clusters (the mass that remains bound in the far future of a {Lambda}CDM universe) is on average (1.99 {+-} 0.11)M{sub 200}, a new observational cosmological test in essential agreement with simulations. Summed profiles binned in M{sub 200} and in L{sub X} demonstrate that the predicted Navarro-Frenk-White form of the density profile is a remarkably good representation of the data in agreement with weak lensing results extending to large radius. The concentration of these summed profiles is also consistent with theoretical predictions.

Rines, Kenneth [Department of Physics and Astronomy, Western Washington University, Bellingham, WA 98225 (United States)] [Department of Physics and Astronomy, Western Washington University, Bellingham, WA 98225 (United States); Geller, Margaret J.; Kurtz, Michael J. [Smithsonian Astrophysical Observatory, 60 Garden Street, MS 20, Cambridge, MA 02138 (United States)] [Smithsonian Astrophysical Observatory, 60 Garden Street, MS 20, Cambridge, MA 02138 (United States); Diaferio, Antonaldo, E-mail: kenneth.rines@wwu.edu, E-mail: diaferio@ph.unito.it [Dipartimento di Fisica, Universita di Torino, Torino (Italy)] [Dipartimento di Fisica, Universita di Torino, Torino (Italy)

2013-04-10T23:59:59.000Z

408

Defining And Characterizing Sample Representativeness For DWPF Melter Feed Samples  

SciTech Connect (OSTI)

Representative sampling is important throughout the Defense Waste Processing Facility (DWPF) process, and the demonstrated success of the DWPF process to achieve glass product quality over the past two decades is a direct result of the quality of information obtained from the process. The objective of this report was to present sampling methods that the Savannah River Site (SRS) used to qualify waste being dispositioned at the DWPF. The goal was to emphasize the methodology, not a list of outcomes from those studies. This methodology includes proven methods for taking representative samples, the use of controlled analytical methods, and data interpretation and reporting that considers the uncertainty of all error sources. Numerous sampling studies were conducted during the development of the DWPF process and still continue to be performed in order to evaluate options for process improvement. Study designs were based on use of statistical tools applicable to the determination of uncertainties associated with the data needs. Successful designs are apt to be repeated, so this report chose only to include prototypic case studies that typify the characteristics of frequently used designs. Case studies have been presented for studying in-tank homogeneity, evaluating the suitability of sampler systems, determining factors that affect mixing and sampling, comparing the final waste glass product chemical composition and durability to that of the glass pour stream sample and other samples from process vessels, and assessing the uniformity of the chemical composition in the waste glass product. Many of these studies efficiently addressed more than one of these areas of concern associated with demonstrating sample representativeness and provide examples of statistical tools in use for DWPF. The time when many of these designs were implemented was in an age when the sampling ideas of Pierre Gy were not as widespread as they are today. Nonetheless, the engineers and statisticians used carefully thought out designs that systematically and economically provided plans for data collection from the DWPF process. Key shared features of the sampling designs used at DWPF and the Gy sampling methodology were the specification of a standard for sample representativeness, an investigation that produced data from the process to study the sampling function, and a decision framework used to assess whether the specification was met based on the data. Without going into detail with regard to the seven errors identified by Pierre Gy, as excellent summaries are readily available such as Pitard [1989] and Smith [2001], SRS engineers understood, for example, that samplers can be biased (Gy?s extraction error), and developed plans to mitigate those biases. Experiments that compared installed samplers with more representative samples obtained directly from the tank may not have resulted in systematically partitioning sampling errors into the now well-known error categories of Gy, but did provide overall information on the suitability of sampling systems. Most of the designs in this report are related to the DWPF vessels, not the large SRS Tank Farm tanks. Samples from the DWPF Slurry Mix Evaporator (SME), which contains the feed to the DWPF melter, are characterized using standardized analytical methods with known uncertainty. The analytical error is combined with the established error from sampling and processing in DWPF to determine the melter feed composition. This composition is used with the known uncertainty of the models in the Product Composition Control System (PCCS) to ensure that the wasteform that is produced is comfortably within the acceptable processing and product performance region. Having the advantage of many years of processing that meets the waste glass product acceptance criteria, the DWPF process has provided a considerable amount of data about itself in addition to the data from many special studies. Demonstrating representative sampling directly from the large Tank Farm tanks is a difficult, if not unsolvable enterprise due to li

Shine, E. P.; Poirier, M. R.

2013-10-29T23:59:59.000Z

409

UPMASK: unsupervised photometric membership assignment in stellar clusters  

E-Print Network [OSTI]

We develop a method for membership assignment in stellar clusters using only photometry and positions. The method, UPMASK, is aimed to be unsupervised, data driven, model free, and to rely on as few assumptions as possible. It is based on an iterative process, principal component analysis, clustering algorithm, and kernel density estimations. Moreover, it is able to take into account arbitrary error models. An implementation in R was tested on simulated clusters that covered a broad range of ages, masses, distances, reddenings, and also on real data of cluster fields. Running UPMASK on simulations showed that it effectively separates cluster and field populations. The overall spatial structure and distribution of cluster member stars in the colour-magnitude diagram were recovered under a broad variety of conditions. For a set of 360 simulations, the resulting true positive rates (a measurement of purity) and member recovery rates (a measurement of completeness) at the 90% membership probability level reached ...

Krone-Martins, A

2013-01-01T23:59:59.000Z

410

Experimental studies of the chemistry of metal clusters  

SciTech Connect (OSTI)

The procedures for studying chemical reactions of metal clusters in a continuous-flow reactor are described, and examples of such studies are given. Experiments to be discussed include kinetics and thermodynamics measurements, and determination of the composition of clusters saturated with various adsorbate reagents. Specific systems to be covered include the reaction of iron clusters with ammonia and with hydrogen, the reaction of nickel clusters with hydrogen and with ammonia, and the reaction of platinum clusters with ethylene. The last two reactions are characterized by complex, multi-step processes that lead to adsorbate decomposition and hydrogen desorption from the clusters. Methods for probing these processes will be discussed. 26 refs., 8 figs.

Parks, E.K.; Riley, S.J.

1988-01-01T23:59:59.000Z

411

THE INFRARED SPECTROSCOPY OF NEUTRAL POLYCYCLIC AROMATIC HYDROCARBON CLUSTERS  

SciTech Connect (OSTI)

The mid-infrared spectra of neutral homogeneous polycyclic aromatic hydrocarbon (PAH) clusters have been computed using density functional theory including an empirical correction for dispersion. The C-H out-of-plane bending modes are redshifted for all the clusters considered in this work. The magnitude of the redshift and the peak broadening are dependent on PAH size, shape, and on the PAH arrangement in the cluster.

Ricca, Alessandra [Carl Sagan Center, SETI Institute, 189 Bernardo Avenue, Suite 100, Mountain View, CA 94043 (United States); Bauschlicher, Charles W. Jr. [Entry Systems and Technology Division, Mail Stop 230-3, NASA Ames Research Center, Moffett Field, CA 94035 (United States); Allamandola, Louis J., E-mail: Alessandra.Ricca-1@nasa.gov, E-mail: Charles.W.Bauschlicher@nasa.gov [Space Science Division, Mail Stop 245-6, NASA Ames Research Center, Moffett Field, CA 94035 (United States)

2013-10-10T23:59:59.000Z

412

Issues in the Formation of Globular Cluster Systems  

E-Print Network [OSTI]

Recent developments relevant to the formation of globular cluster systems in galaxies are discussed, including (1) The age distribution of the oldest Milky Way clusters, (2) Subgroups and possible accretion and merger remnants in the Galactic halo, (3) Key features of globular cluster systems in giant elliptical galaxies (metallicity distribution functions, luminosity distribution functions, specific frequencies). Processes contributing to the formation of giant ellipticals are summarized.

W. E. Harris

1998-01-21T23:59:59.000Z

413

Field Sampling | Open Energy Information  

Open Energy Info (EERE)

form form View source History View New Pages Recent Changes All Special Pages Semantic Search/Querying Get Involved Help Apps Datasets Community Login | Sign Up Search Page Edit with form History Facebook icon Twitter icon » Field Sampling Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Field Sampling Details Activities (0) Areas (0) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Field Techniques Exploration Sub Group: Field Sampling Parent Exploration Technique: Field Techniques Information Provided by Technique Lithology: Rock samples are used to define lithology. Field and lab analyses can be used to measure the chemical and isotopic constituents of rock samples. Stratigraphic/Structural: Can reveal relatively high permeability zones. Provides information about the time and environment which formed a particular geologic unit. Microscopic rock textures can be used to estimate the history of stress and strain, and/or faulting.

414

Potential energy surfaces for cluster emitting nuclei  

SciTech Connect (OSTI)

Potential energy surfaces are calculated by use of the most advanced asymmetric two-center shell model that allows us to obtain shell-and-pairing corrections that are added to the Yukawa-plus-exponential model deformation energy. Shell effects are of crucial importance for the experimental observation of spontaneous disintegration by heavy-ion emission. Results for {sup 222}Ra, {sup 232}U, {sup 236}Pu, and {sup 242}Cm illustrate the main ideas and show for the first time, for a cluster emitter, a potential barrier obtained by use of the macroscopic-microscopic method.

Poenaru, Dorin N.; Gherghescu, Radu A. [Horia Hulubei National Institute of Physics and Nuclear Engineering, RO-077125 Bucharest-Magurele (Romania); Frankfurt Institute for Advanced Studies, J. W. Goethe Universitaet, Max-von-Laue-Strasse 1, D-60438 Frankfurt (Germany); Greiner, Walter [Frankfurt Institute for Advanced Studies, J. W. Goethe Universitaet, Max-von-Laue-Strasse 1, D-60438 Frankfurt (Germany)

2006-01-15T23:59:59.000Z

415

Clusters in nuclear matter and Mott points  

E-Print Network [OSTI]

Light clusters (mass number $A \\leq 4$) in nuclear matter at subsaturation densities are described using a quantum statistical approach. In addition to self-energy and Pauli-blocking, effects of continuum correlations are taken into account to calculate the quasiparticle properties and abundances of light elements. Medium-modified quasiparticle properties are important ingredients to derive a nuclear matter equation of state applicable in the entire region of warm dense matter below saturation density. The influence of the nucleon-nucleon interaction on the quasiparticle shift is discussed.

Röpke, G

2015-01-01T23:59:59.000Z

416

Clustering properties of dynamical dark energy models  

SciTech Connect (OSTI)

We provide a generic but physically clear discussion of the clustering properties of dark energy models. We explicitly show that in quintessence-type models the dark energy fluctuations, on scales smaller than the Hubble radius, are of the order of the perturbations to the Newtonian gravitational potential, hence necessarily small on cosmological scales. Moreover, comparable fluctuations are associated with different gauge choices. We also demonstrate that the often used homogeneous approximation is unrealistic, and that the so-called dark energy mutation is a trivial artifact of an effective, single fluid description. Finally, we discuss the particular case where the dark energy fluid is nonminimally coupled to dark matter.

Avelino, P. P.; Beca, L. M. G. [Centro de Fisica do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); Departamento de Fisica da Faculdade de Ciencias da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); Martins, C. J. A. P. [Centro de Astrofisica, Universidade do Porto, Rua das Estrelas s/n, 4150-762 Porto (Portugal); DAMTP, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom)

2008-05-15T23:59:59.000Z

417

XANES of high-pressure Kr clusters in Be and Si  

Science Journals Connector (OSTI)

We report on the experimental investigation of high-pressure Kr clusters in Be and Si single crystals by x-ray absorption near-edge spectroscopy. The samples, obtained by ion implantation, were investigated for several temperatures in the range 83–670 K. We show that the near-edge structure of the absorption spectra is sufficient to obtain valuable quantitative information concerning the contracted lattice parameter of the solid rare gas agglomerates, depending on the overpressure exerted on the clusters by the host matrix. Our data compare to the extended x-ray absorption fine structure (EXAFS) experimental spectra on solid Kr at 4.2 K, and at 300 K under high pressure. Furthermore, in order to check the consistency of our experimental data with EXAFS results taken from the literature, we performed theoretical simulations using the FEFF6 code. These calculations showed good agreement with both sets of data and confirmed our experimental conclusions, permitting the evaluation of the lattice contraction, average coordination, and size of the cluster ensemble.

Giuseppe Faraci; Agata R. Pennisi; Jean-Louis Hazemann

1997-11-15T23:59:59.000Z

418

Stromgren photometry of Galactic Globular Clusters. II Metallicity distribution of red giants in Omega Centauri  

E-Print Network [OSTI]

We present new intermediate-band Stroemgren photometry based on more than 300 u,v,b,y images of the Galactic globular cluster Omega Cen. Optical data were supplemented with new multiband near-infrared (NIR) photometry (350 J,H,K_s images). The final optical-NIR catalog covers a region of more than 20*20 arcmin squared across the cluster center. We use different optical-NIR color-color planes together with proper motion data available in the literature to identify candidate cluster red giant (RG) stars. By adopting different Stroemgren metallicity indices we estimate the photometric metallicity for ~4,000 RGs, the largest sample ever collected. The metallicity distributions show multiple peaks ([Fe/H]_phot=-1.73+/-0.08,-1.29+/-0.03,-1.05+/-0.02,-0.80+/-0.04,-0.42+/-0.12 and -0.07+/-0.08 dex) and a sharp cut-off in the metal-poor tail ([Fe/H]_phot-1.7 dex).

Calamida, A; Stetson, P B; Freyhammer, L M; Piersimoni, A M; Buonanno, R; Caputo, F; Cassisi, S; Castellani, M; Corsi, C E; Dall'Ora, M; Degl'Innocenti, S; Ferraro, I; Grundahl, F; Hilker, M; Monelli, M; Nonino, M; Patat, N; Pietrinferni, A; Moroni, P G Prada; Primas, F; Pulone, L; Richtler, T; Romaniello, M; Storm, J; Walker, A R

2009-01-01T23:59:59.000Z

419

The environmental dependence of galaxy clustering in the Sloan Digital Sky Survey  

E-Print Network [OSTI]

A generic prediction of hierarchical clustering models is that the mass function of dark haloes in dense regions in the Universe should be top-heavy. We provide a novel test of this prediction using a sample of galaxies drawn from the Sloan Digital Sky Survey. To perform the test, we compare measurements of galaxy clustering in dense and underdense regions. We find that galaxies in dense regions cluster significantly more strongly than those in less dense regions. This is true over the entire 0.1--30 Mpc pair separation range for which we can make accurate measurements. We make similar measurements in realistic mock catalogs in which the only environmental effects are those which arise from the predicted correlation between halo mass and environment. We also provide an analytic halo-model based calculation of the effect. Both the mock catalogs and the analytic calculation provide rather good descriptions of the SDSS measurements. Thus, our results provide strong support for hierarchical models. They suggest that, unless care is taken to study galaxies at fixed mass, correlations between galaxy properties and the surrounding environment are almost entirely due to more fundamental correlations between galaxy properties and host halo mass, and between halo mass and environment.

Ummi Abbas; Ravi K. Sheth

2006-01-18T23:59:59.000Z

420

THE SNAPSHOT HUBBLE U-BAND CLUSTER SURVEY (SHUCS). I. SURVEY DESCRIPTION AND FIRST APPLICATION TO THE MIXED STAR CLUSTER POPULATION OF NGC 4041  

SciTech Connect (OSTI)

We present the Snapshot Hubble U-band Cluster Survey (SHUCS), a project aimed at characterizing the star cluster populations of 10 nearby galaxies (d < 23 Mpc, half within Almost-Equal-To 12 Mpc) through new F336W (U-band equivalent) imaging from Wide Field Camera 3, and archival BVI-equivalent data with the Hubble Space Telescope. Completing the UBVI baseline reduces the age-extinction degeneracy of optical colors, thus enabling the measurement of reliable ages and masses for the thousands of clusters covered by our survey. The sample consists chiefly of face-on spiral galaxies at low inclination, in various degrees of isolation (isolated, in group, merging), and includes two active galactic nucleus hosts. This first paper outlines the survey itself, the observational datasets, the analysis methods, and presents a proof-of-concept study of the large-scale properties and star cluster population of NGC 4041, a massive SAbc galaxy at a distance of Almost-Equal-To 23 Mpc, and part of a small grouping of six giant members. We resolve two structural components with distinct stellar populations, a morphology more akin to merging and interacting systems. We also find strong evidence of a truncated, Schechter-type mass function, and a similarly segmented luminosity function. These results indicate that binning must erase much of the substructure present in the mass and luminosity functions, and might account for the conflicting reports on the intrinsic shape of these functions in the literature. We also note a tidal feature in the outskirts of the galaxy in Galaxy Evolution Explorer UV imaging, and follow it up with a comprehensive multi-wavelength study of NGC 4041 and its parent group. We deduce a minor merger as a likely cause of its segmented structure and the observed pattern of a radially decreasing star formation rate. We propose that combining the study of star cluster populations with broadband metrics is not only advantageous, but often easily achievable thorough archival datasets.

Konstantopoulos, I. S. [Australian Astronomical Observatory, P.O. Box 915, North Ryde NSW 1670 (Australia); Smith, L. J. [Space Telescope Science Institute and European Space Agency, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Adamo, A. [Max-Planck-Institut for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany); Silva-Villa, E. [Departement de Physique, de Genie Physique et d'Optique, and Centre de Recherche en Astrophysique du Quebec (CRAQ), Universite Laval, Quebec (Canada); Gallagher, J. S.; Ryon, J. E. [Department of Astronomy, University of Wisconsin-Madison, 5534 Sterling, 475 North Charter Street, Madison WI 53706 (United States); Bastian, N. [Astrophysics Research Institute, Liverpool John Moores University, Egerton Wharf, Birkenhead, CH41 1LD (United Kingdom); Westmoquette, M. S. [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching bei Muenchen (Germany); Zackrisson, E. [Department of Astronomy, Stockholm University, Oscar Klein Centre, AlbaNova, Stockholm SE-106 91 (Sweden); Larsen, S. S. [Department of Astrophysics/IMAPP, Radboud University Nijmegen, P.O. Box 9010, 6500 GL Nijmegen (Netherlands); Weisz, D. R. [Department of Astronomy, Box 351580, University of Washington, Seattle, WA 98195 (United States); Charlton, J. C., E-mail: iraklis@aao.gov.au [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States)

2013-05-15T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Multi-agent Cluster Scheduling for Scalability and Flexibility  

E-Print Network [OSTI]

of clusters scheduling and classical concurrency controlotherwise push control of task scheduling and execution towhich actively controls and modifies scheduling domains as

Konwinski, Andrew David

2012-01-01T23:59:59.000Z

422

Using Cluster Road Mapping to Determine Strategic Clean Energy Direction  

Broader source: Energy.gov [DOE]

This document contains the transcript for the Using Cluster Roadmapping to Determine Your Strategic Clean Energy Direction webinar held on May 16, 2013.

423

On the efficiency of field star capture by star clusters  

E-Print Network [OSTI]

An exciting recent finding regarding scaling relations among globular clusters is the so-called 'blue tilt': clusters of the blue sub-population follow a trend of redder colour with increasing luminosity. In this paper we evaluate to which extent field star capture over a Hubble time may explain the 'blue tilt'. We perform collisional N-body simulations to quantify the amount of field star capture occuring over a Hubble time to star clusters with 10^3 to 10^6 stars. In the simulations we follow the orbits of field stars passing through a star cluster and calculate the energy change that the field stars experience due to gravitational interaction with cluster stars during one passage through the cluster. The capture condition is that their total energy after the passage is smaller than the gravitational potential at the cluster's tidal radius. By folding this with the fly-by rates of field stars with an assumed space density as in the solar neighbourhood and a range of velocity dispersions, we derive estimates on the mass fraction of captured field stars as a function of environment. We find that integrated over a Hubble time, the ratio between captured field stars and total number of clusters stars is very low (capture is not a probable mechanism for creating the colour-magnitude trend of metal-poor globular clusters.

Steffen Mieske; Holger Baumgardt

2007-09-10T23:59:59.000Z

424

Computer System, Cluster and Networking Summer Institute (CSCNSI...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

CSCNSI Computer System, Cluster and Networking Summer Institute (CSCNSI) Emphasizes practical skill development. Contact Leader Francis J. Alexander (505) 665-4518 Email Deputy...

425

Deploying applications in multi-SAN SMP clusters  

Science Journals Connector (OSTI)

The effective exploitation of multi-SAN SMP clusters and the use of generic clusters to support complex information systems require new approaches; multi-SAN SMP clusters introduce new levels of parallelism and traditional environments are mainly used to run scientific computations. In this paper we present a novel approach to the exploitation of clusters that allows integrating in a unique metaphor: the representation of physical resources, the modelling of applications and the mapping of application into physical resources. The proposed abstractions favoured the development of an API that allows combining and benefiting from the shared memory, message passing and global memory paradigms.

Albano Alves; Antonio Pina; Jose Exposto; Jose Rufino

2009-01-01T23:59:59.000Z

426

Cluster States for Continuous-Variable Multipartite Entanglement  

E-Print Network [OSTI]

We introduce a new class of continuous-variable (CV) multipartite entangled states, the CV cluster states, which might be generated from squeezing and kerr-like interaction. The entanglement properties of these states are studied in terms of classical communication and local operations. The quantum teleportation network with cluster states is investigated. The graph states as the general forms of cluster states are presented, which may be used to generate CV Greenberger-Horne-Zeilinger states by simply local measurements and classical communication. A chain for one-dimensional example of cluster states can be readily experimentally produced only with squeezed light and beamsplitters.

Jing Zhang

2005-01-20T23:59:59.000Z

427

Three-dimensional Modeling of Fracture Clusters in Geeothermal Reservoirs  

Broader source: Energy.gov [DOE]

Three-dimensional Modeling of Fracture Clusters in Geeothermal Reservoirs presentation at the April 2013 peer review meeting held in Denver, Colorado.

428

Three-dimensional Modeling of Fracture Clusters in Geothermal...  

Broader source: Energy.gov (indexed) [DOE]

1 4.6.1 Three-dimensional Modeling of Fracture Clusters in Geothermal Reservoirs Presentation Number: 028 Investigator: Ghassemi, Ahmad (Texas A&M University) Objectives: To...

429

Cluster Analysis of Cloud Regimes and Characteristic Dynamics...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Cluster Analysis of Cloud Regimes and Characteristic Dynamics of Mid-Latitude Synoptic Systems N. D. Gordon and J. R. Norris Scripps Institution of Oceanography University of...

430

Orbital Magnetism: Pros and Cons for Enhancing the Cluster Magnetism  

Science Journals Connector (OSTI)

The discrepancy seen in the experimental and theoretical results on the magnetic moment of a small magnetic cluster has been attributed to the contribution arising from orbital magnetism. In this Letter we show that the magnetic states with large orbital magnetic moment are not always energetically favorable; they could, however, be realizable by coating the cluster or deposing it on appropriate substrates. More importantly, our work shows that the crucial factors that determine the cluster magnetism are found to be the intrinsic, and consequently, the extrinsic properties of the constituent atoms of the cluster.

Antonis N. Andriotis and Madhu Menon

2004-07-09T23:59:59.000Z

431

Construction of Heterometallic Clusters in a small peptide scaffold...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Construction of Heterometallic Clusters in a small peptide scaffold as NiFe-hydrogenase models: Development of a Synthetic Methodology Authors: Dutta, A., Hamilton, G. A.,...

432

Aluminum Zintl anion moieties within sodium aluminum clusters  

SciTech Connect (OSTI)

Through a synergetic combination of anion photoelectron spectroscopy and density functional theory based calculations, we have established that aluminum moieties within selected sodium-aluminum clusters are Zintl anions. Sodium–aluminum cluster anions, Na{sub m}Al{sub n}{sup ?}, were generated in a pulsed arc discharge source. After mass selection, their photoelectron spectra were measured by a magnetic bottle, electron energy analyzer. Calculations on a select sub-set of stoichiometries provided geometric structures and full charge analyses for both cluster anions and their neutral cluster counterparts, as well as photodetachment transition energies (stick spectra), and fragment molecular orbital based correlation diagrams.

Wang, Haopeng; Zhang, Xinxing; Ko, Yeon Jae; Grubisic, Andrej; Li, Xiang; Ganteför, Gerd; Bowen, Kit H., E-mail: AKandalam@wcupa.edu, E-mail: kiran@mcneese.edu, E-mail: kbowen@jhu.edu [Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Schnöckel, Hansgeorg [Institute of Inorganic Chemistry, Karlsruhe Institute of Technology, 76128 Karlsruhe (Germany)] [Institute of Inorganic Chemistry, Karlsruhe Institute of Technology, 76128 Karlsruhe (Germany); Eichhorn, Bryan W. [Department of Chemistry, University of Maryland at College Park, College Park, Maryland 20742 (United States)] [Department of Chemistry, University of Maryland at College Park, College Park, Maryland 20742 (United States); Lee, Mal-Soon; Jena, P. [Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284 (United States)] [Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284 (United States); Kandalam, Anil K., E-mail: AKandalam@wcupa.edu, E-mail: kiran@mcneese.edu, E-mail: kbowen@jhu.edu [Department of Physics, West Chester University of Pennsylvania, West Chester, Pennsylvania 19383 (United States); Kiran, Boggavarapu, E-mail: AKandalam@wcupa.edu, E-mail: kiran@mcneese.edu, E-mail: kbowen@jhu.edu [Department of Chemistry, McNeese State University, Lake Charles, Louisiana 70609 (United States)] [Department of Chemistry, McNeese State University, Lake Charles, Louisiana 70609 (United States)

2014-02-07T23:59:59.000Z

433

Internal temperatures of neutral sodium clusters: a “PIE-thermometer”  

Science Journals Connector (OSTI)

Distinct temperature effects could be observed in the threshold regions of photoionisation efficiency (PIE) measurements of sodium clusters. Simulations of the PIE thresholds at various temperatures were carried ...

U. Röthlisberger; M. Schär; E. Schumacher

1989-01-01T23:59:59.000Z

434

Investigation of 9Be from nonlocalized clustering concept  

E-Print Network [OSTI]

The nonlocalized aspect of clustering, which is a new concept for self-conjugate nuclei, is extended for the investigation of the N{\

Mengjiao Lyu; Zhongzhou Ren; Bo Zhou; Yasuro Funaki; Hisashi Horiuchi; Gerd Röpke; Peter Schuck; Akihiro Tohsaki; Chang Xu; Taiichi Yamada

2014-08-22T23:59:59.000Z

435

Asymptotic Normality of Shot Noise on Poisson Cluster Processes with Cluster Marks  

E-Print Network [OSTI]

of response function which arise in diverse applications such as semiconductor noise, Cherenkov radiation random durations, possibly infinite. Such stochastic processes arise very naturally in diverse fields process are modeled as occurring in clusters, it is desirable to allow the response functions

Serfling, Robert

436

Star formation in the cluster CLG0218.3-0510 at z=1.62 and its large-scale environment: the infrared perspective  

E-Print Network [OSTI]

The galaxy cluster CLG0218.3-0510 at z=1.62 is one of the most distant galaxy clusters known, with a rich muti-wavelength data set that confirms a mature galaxy population already in place. Using very deep, wide area (20x20 Mpc) imaging by Spitzer/MIPS at 24um, in conjunction with Herschel 5-band imaging from 100-500um, we investigate the dust-obscured, star-formation properties in the cluster and its associated large scale environment. Our galaxy sample of 693 galaxies at z=1.62 detected at 24um (10 spectroscopic and 683 photo-z) includes both cluster galaxies (i.e. within r projected clustercentric radius) and field galaxies, defined as the region beyond a radius of 3 Mpc. The star-formation rates (SFRs) derived from the measured infrared luminosity range from 18 to 2500 Ms/yr, with a median of 55 Ms/yr, over the entire radial range (10 Mpc). The cluster brightest FIR galaxy, taken as the centre of the galaxy system, is vigorously forming stars at a rate of 256$\\pm$70 Ms/yr, and the total cluster ...

Santos, Joana S; Tanaka, Masayuki; Valtchanov, Ivan; Saintonge, Amelie; Dickinson, Mark; Foucaud, Sebastien; Kodama, Tadayuki; Rawle, Tim D; Tadaki, Ken-ichi

2013-01-01T23:59:59.000Z

437

Clusters of galaxies: setting the stage  

E-Print Network [OSTI]

Clusters of galaxies are self-gravitating systems of mass ~10^14-10^15 Msun. They consist of dark matter (~80 %), hot diffuse intracluster plasma (web and form by anisotropic and episodic accretion of mass. In this model of the universe dominated by cold dark matter, at the present time most baryons are expected to be in a diffuse component rather than in stars and galaxies; moreover, ~50 % of this diffuse component has temperature ~0.01-1 keV and permeates the filamentary distribution of the dark matter. The temperature of this Warm-Hot Intergalactic Medium (WHIM) increases with the local density and its search in the outer regions of clusters and lower density regions has been the quest of much recent observational effort. Over the last thirty years, an impressive coherent picture of the formation and evolution of cosmic structures has emerged from the intense interplay between observations, theory and numerical experiments. Future efforts will continue to test whether this picture keeps being valid, needs corrections or suffers dramatic failures in its predictive power.

A. Diaferio; S. Schindler; K. Dolag

2008-01-07T23:59:59.000Z

438

Non-linear dark energy clustering  

SciTech Connect (OSTI)

We consider a dark energy fluid with arbitrary sound speed and equation of state and discuss the effect of its clustering on the cold dark matter distribution at the non-linear level. We write the continuity, Euler and Poisson equations for the system in the Newtonian approximation. Then, using the time renormalization group method to resum perturbative corrections at all orders, we compute the total clustering power spectrum and matter power spectrum. At the linear level, a sound speed of dark energy different from that of light modifies the power spectrum on observationally interesting scales, such as those relevant for baryonic acoustic oscillations. We show that the effect of varying the sound speed of dark energy on the non-linear corrections to the matter power spectrum is below the per cent level, and therefore these corrections can be well modelled by their counterpart in cosmological scenarios with smooth dark energy. We also show that the non-linear effects on the matter growth index can be as large as 10–15 per cent for small scales.

Anselmi, Stefano; Ballesteros, Guillermo [Dipartimento di Fisica ''G. Galilei'', Universitŕ degli Studi di Padova, via Marzolo 8, I-35131 Padua (Italy); Pietroni, Massimo, E-mail: anselmi@pd.infn.it, E-mail: ballesteros@pd.infn.it, E-mail: pietroni@pd.infn.it [INFN — Sezione di Padova, via Marzolo 8, I-35131 Padua (Italy)

2011-11-01T23:59:59.000Z

439

CLUSTERING OF OBSCURED AND UNOBSCURED QUASARS IN THE BOOeTES FIELD: PLACING RAPIDLY GROWING BLACK HOLES IN THE COSMIC WEB  

SciTech Connect (OSTI)

We present the first measurement of the spatial clustering of mid-infrared-selected obscured and unobscured quasars, using a sample in the redshift range 0.7 < z < 1.8 selected from the 9 deg{sup 2} Booetes multiwavelength survey. Recently, the Spitzer Space Telescope and X-ray observations have revealed large populations of obscured quasars that have been inferred from models of the X-ray background and supermassive black hole evolution. To date, little is known about obscured quasar clustering, which allows us to measure the masses of their host dark matter halos and explore their role in the cosmic evolution of black holes and galaxies. In this study, we use a sample of 806 mid-infrared-selected quasars and {approx}250,000 galaxies to calculate the projected quasar-galaxy cross-correlation function w{sub p} (R). The observed clustering yields characteristic dark matter halo masses of log(M{sub halo} [h {sup -1} M{sub sun}]) = 12.7{sup +0.4}{sub -0.6} and 13.3{sup +0.3}{sub -0.4} for unobscured quasars (QSO-1s) and obscured quasars (Obs-QSOs), respectively. The results for QSO-1s are in excellent agreement with previous measurements for optically selected quasars, while we conclude that the Obs-QSOs are at least as strongly clustered as the QSO-1s. We test for the effects of photometric redshift errors on the optically faint Obs-QSOs, and find that our method yields a robust lower limit on the clustering; photo-z errors may cause us to underestimate the clustering amplitude of the Obs-QSOs by at most {approx}20%. We compare our results to previous studies, and speculate on physical implications of stronger clustering for obscured quasars.

Hickox, Ryan C.; Alexander, David M.; Goulding, Andrew D. [Department of Physics, Durham University, South Road, Durham, DH1 3LE (United Kingdom); Myers, Adam D. [Department of Astronomy, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States); Brodwin, Mark; Forman, William R.; Jones, Christine; Murray, Stephen S.; Eisenstein, Daniel; Caldwell, Nelson [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Brown, Michael J. I. [School of Physics, Monash University, Clayton 3800, Victoria (Australia); Cool, Richard J. [Princeton University Observatory, Peyton Hall, Princeton, NJ 08544 (United States); Kochanek, Christopher S. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Dey, Arjun; Jannuzi, Buell T. [National Optical Astronomy Observatory, Tucson, AZ 85726 (United States); Assef, Roberto J.; Eisenhardt, Peter R.; Gorjian, Varoujan; Stern, Daniel [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Le Floc'h, Emeric, E-mail: ryan.hickox@durham.ac.uk. [Laboratoire AIM-Paris-Saclay, CEA/DSM/Irfu-CNRS-Universite Paris Diderot, CE-Saclay, pt courrier 131, 91191 Gif-sur-Yvette (France)

2011-04-20T23:59:59.000Z

440

The galaxy cluster X-ray luminosity--gravitational mass relation in the light of the WMAP 3rd year data  

E-Print Network [OSTI]

The 3rd year WMAP results mark a shift in best fit values of cosmological parameters compared to the 1st year data and the concordance cosmological model. We test the consistency of the new results with previous constraints on cosmological parameters from the HIFLUGCS galaxy cluster sample and the impact of this shift on the X-ray luminosity-gravitational mass relation. The measured X-ray luminosity function combined with the observed luminosity-mass relation are compared to mass functions predicted for given cosmological parameter values. The luminosity function and luminosity-mass relation derived previously from HIFLUGCS are in perfect agreement with mass functions predicted using the best fit parameter values from the 3rd year WMAP data (OmegaM=0.238, sigma8=0.74) and inconsistent with the concordance cosmological model (OmegaM=0.3, sigma8=0.9), assuming a flat Universe. Trying to force consistency with the concordance model requires artificially decreasing the normalization of the luminosity-mass relation by a factor of 2. The shift in best fit values for OmegaM and sigma8 has a significant impact on predictions of cluster abundances. The new WMAP results are now in perfect agreement with previous results on the OmegaM-sigma8 relation determined from the mass function of HIFLUGCS clusters and other X-ray cluster samples (the ``low cluster normalization''). We conclude that - unless the true values of OmegaM and sigma8 differ significantly from the 3rd year WMAP results - the luminosity-mass relation is well described by their previous determination from X-ray observations of clusters, with a conservative upper limit on the bias factor of 1.5. These conclusions are currently being tested in a complete follow-up program of all HIFLUGCS clusters with Chandra and XMM-Newton.

Thomas H. Reiprich

2006-05-22T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Wasted Paper in Pharmaceutical Samples  

Science Journals Connector (OSTI)

...of pills and packaging in one of each brand of drug samples stored in the clinic. All pills were packaged in either foil blister packs or plastic bottles; these were contained in paper-product boxes and accompanied by paper package inserts. Ninety-two packages contained 665 pills (mean [±SD], 7.2±6... To the Editor: Clinicians give pharmaceutical samples provided to clinics by industry sales representatives to patients who are unable to afford medicines or use them as starter packs for patients initiating a new treatment. These samples are usually ...

1999-05-20T23:59:59.000Z

442

Category:Gas Sampling | Open Energy Information  

Open Energy Info (EERE)

Gas Sampling page? For detailed information on Gas Sampling as exploration techniques, click here. Category:Gas Sampling Add.png Add a new Gas Sampling Technique Subcategories This...

443

Sampling based on local bandwidth  

E-Print Network [OSTI]

The sampling of continuous-time signals based on local bandwidth is considered in this thesis. In an intuitive sense, local bandwidth refers to the rate at which a signal varies locally. One would expect that signals should ...

Wei, Dennis

2007-01-01T23:59:59.000Z

444

Sample Business Plan Framework 3  

Broader source: Energy.gov [DOE]

U.S. Department of Energy Better Buildings Neighborhood Program: Sample Business Plan Framework 1: A program seeking to continue operations in the post-grant period as a not-for-profit (NGO) entity.

445

Sample Business Plan Framework 5  

Broader source: Energy.gov [DOE]

U.S. Department of Energy Better Buildings Neighborhood Program: Sample Business Plan Framework 1: A program seeking to continue operations in the post-grant period as a not-for-profit (NGO) entity.

446

Sample Business Plan Framework 2  

Broader source: Energy.gov [DOE]

U.S. Department of Energy Better Buildings Neighborhood Program: Sample Business Plan Framework 1: A program seeking to continue operations in the post-grant period as a not-for-profit (NGO) entity.

447

Sample Business Plan Framework 1  

Broader source: Energy.gov [DOE]

U.S. Department of Energy Better Buildings Neighborhood Program: Sample Business Plan Framework 1: A program seeking to continue operations in the post-grant period as a not-for-profit (NGO) entity.

448

Sample Business Plan Framework 4  

Broader source: Energy.gov [DOE]

U.S. Department of Energy Better Buildings Neighborhood Program: Sample Business Plan Framework 1: A program seeking to continue operations in the post-grant period as a not-for-profit (NGO) entity.

449

E-Print Network 3.0 - acids electronic resource Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

of Dicarboxylic Acid Clusters with Water Molecules Summary: Cluster Phase Chemistry: Gas-Phase Reactions of Anionic Sodium Salts of Dicarboxylic Acid Clusters... -phase...

450

E-Print Network 3.0 - acid electronic resource Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

of Dicarboxylic Acid Clusters with Water Molecules Summary: Cluster Phase Chemistry: Gas-Phase Reactions of Anionic Sodium Salts of Dicarboxylic Acid Clusters... -phase...

451

CLUSTERED MULTIDIMENSIONAL SCALING FOR EXPLORATION IN INFORMATION RETRIEVAL  

E-Print Network [OSTI]

and even hardly improve the exploration process of datasets assumed to be composed of multiple distinctCLUSTERED MULTIDIMENSIONAL SCALING FOR EXPLORATION IN INFORMATION RETRIEVAL Eniko Sz´ekely, ´Eric: clustering, nearest neighbour, multidimensional scaling, exploration. Abstract: The data that needs

Genève, Université de

452

On the Connectivities of Subcritical Random Cluster Models  

E-Print Network [OSTI]

On the Connectivities of Subcritical Random Cluster Models M. Campanino (Bologna) D. Ioffe (Haifa) Y. Velenik (Geneva) M. Campanino, D. Ioffe, Y. Velenik On the Connectivities of Subcritical Random Introduction The random cluster model Main assumption The sets U and K 2 Results Results for subcritical models

Velenik, Yvan

453

Fluctuation theory of connectivities for subcritical random cluster models  

E-Print Network [OSTI]

Fluctuation theory of connectivities for subcritical random cluster models Massimo Campanino subcritical regime; the latter is known to be true, in any dimensions, when q = 1, q = 2, and when q. Campanino et al./Connectivities of subcritical random cluster models 2 variance principle, Ruelle operator

454

Largest cluster in subcritical percolation Martin Z. Bazant  

E-Print Network [OSTI]

Largest cluster in subcritical percolation Martin Z. Bazant Department of Mathematics The statistical behavior of the size or mass of the largest cluster in subcritical percolation on a finite lattice of probability distributions as N . The subcritical segment of the physical manifold (0 p pc) approaches a line

Bazant, Martin Z.

455

Context-based clustering of image search results  

Science Journals Connector (OSTI)

In this work we propose to cluster image search results based on the textual contents of the referring webpages. The natural ambiguity and context-dependence of human languages lead to problems that plague modern image search engines: A user formulating ... Keywords: image clustering, image search, machine learning

Hongqi Wang; Olana Missura; Thomas Gärtner; Stefan Wrobel

2009-09-01T23:59:59.000Z

456

Geodesic Disks and Clustering in a Simple Magdalene G. Borgelt  

E-Print Network [OSTI]

Geodesic Disks and Clustering in a Simple Polygon Magdalene G. Borgelt Marc van Kreveld Jun Luo.cs.uu.nl ISSN: 0924-3275 #12;Geodesic Disks and Clustering in a Simple Polygon Magdalene G. Borgelt European points lying in the interior of P. A geodesic disk GD(p, r) with center p and radius r is the set

Utrecht, Universiteit

457

Food Cluster: A Strategy for Job Growth in North  

E-Print Network [OSTI]

Enterprise Advisors: Toby Nord NJCT: William English, James DeSota, Martin Adams #12;Recommendations Summary, commercial urban ag. business to anchor the food cluster 3. Find smaller urban farming businesses to serve simultaneously addressing market needs 3 #12;Economic Benefits of Food Clusters Reduces energy use Cities

Minnesota, University of

458

Rural Knowledge Clusters: Innovation and Vitality in America's Rural Communities  

E-Print Network [OSTI]

Rural Knowledge Clusters: Innovation and Vitality in America's Rural Communities Prepared for: U Knowledge Clusters: Innovation and Vitality in America's Rural Communities Table of Contents Executive Summary 1 I. Context: The Challenge of Rural Community Vitality in a Knowledge-Based Global Economy 5 II

Levinson, David M.

459

Enhancing Single-Objective Projective Clustering Ensembles Francesco Gullo  

E-Print Network [OSTI]

Ensembles (PCE) has re- cently been formulated to solve the problem of deriving a robust projective consensus clustering from an ensemble of projective clustering solutions [1]. PCE is formalized. A major result in [1] is that single-objective PCE outperforms two-objective PCE in terms of efficiency

Domeniconi, Carlotta

460

FORECASTING WATER DEMAND USING CLUSTER AND REGRESSION ANALYSIS  

E-Print Network [OSTI]

resources resulting in water stress. Effective water management ­ a solution Supply side management Demand side management #12;Developing a regression equation based on cluster analysis for forecasting waterFORECASTING WATER DEMAND USING CLUSTER AND REGRESSION ANALYSIS by Bruce Bishop Professor of Civil

Keller, Arturo A.

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461

Hierarchical clustering using correlation metric and spatial continuity constraint  

DOE Patents [OSTI]

Large data sets are analyzed by hierarchical clustering using correlation as a similarity measure. This provides results that are superior to those obtained using a Euclidean distance similarity measure. A spatial continuity constraint may be applied in hierarchical clustering analysis of images.

Stork, Christopher L.; Brewer, Luke N.

2012-10-02T23:59:59.000Z

462

Retro: concept-based clustering of biomedical topical sets  

Science Journals Connector (OSTI)

......other topics following a standard approach. As shown in...of the algorithm. We plan to do this in future...clustering algorithms. In: Mining Text Data-Aggarwal...et al. The WEKA data mining software: an update...Data clustering: a review. ACM Comput. Surveys......

Lana Yeganova; Won Kim; Sun Kim; W. John Wilbur

2014-08-01T23:59:59.000Z

463

Clusters and Superclusters in the Las Campanas Redshift Survey  

E-Print Network [OSTI]

Two-dimensional high-resolution density field of galaxies of the Las Campanas Redshift Survey (LCRS) with a smoothing length 0.8 Mpc/h is used to extract clusters and groups of galaxies, and a low-resolution field with a smoothing length 10 Mpc/h to find superclusters of galaxies. Properties of these density field (DF) clusters and superclusters are studied and compared with the properties of Abell clusters and superclusters, and LCRS loose groups. We calculate the DF-cluster luminosity function, and show that most luminous clusters in high-density environments are about ten times brighter than most luminous clusters in low-density environments. We present a catalogue of DF-superclusters and show that superclusters that contain Abell clusters are richer and more luminous than superclusters without Abell clusters. A pdf file of the paper with high-resolution figures is available in Tartu Observatory web-site (http://www.aai.ee/~maret/cosmoweb.html)

J. Einasto; M. Einasto; G. H"utsi; E. Saar; D. L. Tucker; E. Tago; V. M"uller; P. Hein"am"aki; S. S. Allam

2003-04-30T23:59:59.000Z

464

High–intensity lasers: interactions with atoms, molecules and clusters  

Science Journals Connector (OSTI)

...tra from around 2500-atom xenon clusters irradiated by 2 1016...charge states up to 12+ in xenon and 8+ in krypton at an intensity...process converts the coherent oscillation energy of the electron cloud...result of a resonantly driven oscillation of the entire cluster elec...

1998-01-01T23:59:59.000Z

465

Probing Metagenomics by Rapid Cluster Analysis of Very Large Datasets  

E-Print Network [OSTI]

Probing Metagenomics by Rapid Cluster Analysis of Very Large Datasets Weizhong Li1 , John C. Wooley PLoS Biol 5, e16). Such datasets, not only by their sheer size, but also by many other features, defy datasets by advanced clustering strategies using the newly modified CD-HIT algorithm. We performed