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Apache Corporation
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About: Apache Corporation is a based out in . It is known for research contribution in the topics: Galaxy & Redshift. The organization has 855 authors who have published 1275 publications receiving 117091 citations.
Topics: Galaxy, Redshift, Stars, Quasar, Population
Papers published on a yearly basis
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TL;DR: The recent declines in morbidity and mortality due to AIDS are attributable to the use of more intensive antiretroviral therapies.
Abstract: Background and Methods National surveillance data show recent, marked reductions in morbidity and mortality associated with the acquired immunodeficiency syndrome (AIDS). To evaluate these declines, we analyzed data on 1255 patients, each of whom had at least one CD4+ count below 100 cells per cubic millimeter, who were seen at nine clinics specializing in the treatment of human immunodeficiency virus (HIV) infection in eight U.S. cities from January 1994 through June 1997. Results Mortality among the patients declined from 29.4 per 100 person-years in 1995 to 8.8 per 100 person-years in the second quarter of 1997. There were reductions in mortality regardless of sex, race, age, and risk factors for transmission of HIV. The incidence of any of three major opportunistic infections (Pneumocystis carinii pneumonia, Mycobacterium avium complex disease, and cytomegalovirus retinitis) declined from 21.9 per 100 person-years in 1994 to 3.7 per 100 person-years by mid-1997. In a failure-rate model, increases in t...
9,116 citations
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University of Arizona1, Sloan Fellows2, New York University3, University of Pittsburgh4, Massachusetts Institute of Technology5, University of Pennsylvania6, Institute for Advanced Study7, University of Washington8, Fermilab9, Princeton University10, Apache Corporation11, Spanish National Research Council12, Eötvös Loránd University13, University of Tokyo14, University of Chicago15, Johns Hopkins University16, University of Colorado Boulder17, Space Telescope Science Institute18, University of Michigan19, University of Edinburgh20, Rochester Institute of Technology21, Lawrence Berkeley National Laboratory22, Pennsylvania State University23, Adler Planetarium24, University of Hawaii25
TL;DR: In this paper, a large-scale correlation function measured from a spectroscopic sample of 46,748 luminous red galaxies from the Sloan Digital Sky Survey is presented, which demonstrates the linear growth of structure by gravitational instability between z ≈ 1000 and the present and confirms a firm prediction of the standard cosmological theory.
Abstract: We present the large-scale correlation function measured from a spectroscopic sample of 46,748 luminous red galaxies from the Sloan Digital Sky Survey. The survey region covers 0.72h −3 Gpc 3 over 3816 square degrees and 0.16 < z < 0.47, making it the best sample yet for the study of large-scale structure. We find a well-detected peak in the correlation function at 100h −1 Mpc separation that is an excellent match to the predicted shape and location of the imprint of the recombination-epoch acoustic oscillations on the low-redshift clustering of matter. This detection demonstrates the linear growth of structure by gravitational instability between z ≈ 1000 and the present and confirms a firm prediction of the standard cosmological theory. The acoustic peak provides a standard ruler by which we can measure the ratio of the distances to z = 0.35 and z = 1089 to 4% fractional accuracy and the absolute distance to z = 0.35 to 5% accuracy. From the overall shape of the correlation function, we measure the matter density mh 2 to 8% and find agreement with the value from cosmic microwave background (CMB) anisotropies. Independent of the constraints provided by the CMB acoustic scale, we find m = 0.273 ±0.025+0.123(1+ w0)+0.137K. Including the CMB acoustic scale, we find that the spatial curvature is K = −0.010 ± 0.009 if the dark energy is a cosmological constant. More generally, our results provide a measurement of cosmological distance, and hence an argument for dark energy, based on a geometric method with the same simple physics as the microwave background anisotropies. The standard cosmological model convincingly passes these new and robust tests of its fundamental properties. Subject headings: cosmology: observations — large-scale structure of the universe — distance scale — cosmological parameters — cosmic microwave background — galaxies: elliptical and lenticular, cD
4,428 citations
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TL;DR: In this paper, the authors examined the properties of the host galaxies of 22 623 narrow-line active galactic nuclei (AGN) with 0.02 < z < 0.3 selected from a complete sample of 122 808 galaxies from the Sloan Digital Sky Survey.
Abstract: We examine the properties of the host galaxies of 22 623 narrow-line active galactic nuclei (AGN) with 0.02 < z < 0.3 selected from a complete sample of 122 808 galaxies from the Sloan Digital Sky Survey. We focus on the luminosity of the [O III] λ5007 emission line as a tracer of the strength of activity in the nucleus. We study how AGN host properties compare with those of normal galaxies and how they depend on L[O III]. We find that AGN of all luminosities reside almost exclusively in massive galaxies and have distributions of sizes, stellar surface mass densities and concentrations that are similar to those of ordinary early-type galaxies in our sample. The host galaxies of low-luminosity AGN have stellar populations similar to normal early types. The hosts of high-luminosity AGN have much younger mean stellar ages. The young stars are not preferentially located near the nucleus of the galaxy, but are spread out over scales of at least several kiloparsecs. A significant fraction of high-luminosity AGN have strong Hδ absorption-line equivalent widths, indicating that they experienced a burst of star formation in the recent past. We have also examined the stellar populations of the host galaxies of a sample of broad-line AGN. We conclude that there is no significant difference in stellar content between type 2 Seyfert hosts and quasars (QSOs) with the same [O III] luminosity and redshift. This establishes that a young stellar population is a general property of AGN with high [O III] luminosities.
3,781 citations
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TL;DR: The overall predictive accuracy of the first-day APACHE III equation was such that, within 24 h ofICU admission, 95 percent of ICU admissions could be given a risk estimate for hospital death that was within 3 percent of that actually observed.
3,693 citations
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TL;DR: In this paper, the relation between stellar mass and gas-phase metallicity was studied using the Sloan Digital Sky Survey imaging and spectroscopy of ~53,000 star-forming galaxies at z = 0.1.
Abstract: We utilize Sloan Digital Sky Survey imaging and spectroscopy of ~53,000 star-forming galaxies at z ~ 0.1 to study the relation between stellar mass and gas-phase metallicity. We derive gas-phase oxygen abundances and stellar masses using new techniques that make use of the latest stellar evolutionary synthesis and photoionization models. We find a tight (?0.1 dex) correlation between stellar mass and metallicity spanning over 3 orders of magnitude in stellar mass and a factor of 10 in metallicity. The relation is relatively steep from 108.5 to 1010.5 M? h, in good accord with known trends between luminosity and metallicity, but flattens above 1010.5 M?. We use indirect estimates of the gas mass based on the H? luminosity to compare our data to predictions from simple closed box chemical evolution models. We show that metal loss is strongly anticorrelated with baryonic mass, with low-mass dwarf galaxies being 5 times more metal depleted than L* galaxies at z ~ 0.1. Evidence for metal depletion is not confined to dwarf galaxies but is found in galaxies with masses as high as 1010 M?. We interpret this as strong evidence of both the ubiquity of galactic winds and their effectiveness in removing metals from galaxy potential wells.
3,621 citations
Authors
Showing all 856 results
Name | H-index | Papers | Citations |
---|---|---|---|
Donald G. York | 160 | 681 | 156579 |
Jon Brinkmann | 114 | 163 | 93992 |
Dmitry Bizyaev | 110 | 449 | 69001 |
Kaike Pan | 107 | 357 | 67940 |
István Csabai | 104 | 356 | 69903 |
J. Brinkmann | 93 | 169 | 54958 |
Daniel Oravetz | 91 | 204 | 54914 |
Dan Long | 88 | 148 | 75324 |
Stephanie A. Snedden | 86 | 156 | 52683 |
Elena Malanushenko | 86 | 167 | 45511 |
Viktor Malanushenko | 85 | 162 | 52537 |
J. Brinkmann | 84 | 155 | 29556 |
Audrey Simmons | 75 | 148 | 33396 |
Howard Brewington | 74 | 125 | 37829 |
Eric H. Neilsen | 70 | 168 | 47969 |