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Institution

National University of La Plata

EducationLa Plata, Argentina
About: National University of La Plata is a education organization based out in La Plata, Argentina. It is known for research contribution in the topics: Population & Large Hadron Collider. The organization has 12993 authors who have published 30013 publications receiving 495118 citations. The organization is also known as: UNLP & Universidad Nacional de La Plata.


Papers
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Journal ArticleDOI
TL;DR: In this paper, the generalization of the Jensen-Shannon divergence in the context of quantum theory has been studied, and it has been shown that its square root verifies the triangle inequality.
Abstract: In a recent paper, the generalization of the Jensen-Shannon divergence in the context of quantum theory has been studied [Majtey et al., Phys. Rev. A 72, 052310 (2005)]. This distance between quantum states has shown to verify several of the properties required for a good distinguishability measure. Here we investigate the metric character of this distance. More precisely we show, formally for pure states and by means of a numerical procedure for mixed states, that its square root verifies the triangle inequality.

131 citations

Journal ArticleDOI
TL;DR: In this article, the effects of active galactic nuclei feedback on the formation and evolution of galaxies in a semi-analytic model of galaxy formation were investigated. But the model was not considered in this paper, and it is assumed that feedback from AGN operates in the later case.
Abstract: We study the effects of Active Galactic Nuclei (AGN) feedback on the formation and evolution of galaxies in a semi-analytic model of galaxy formation. This model is an improved version of the one described by Cora (2006), which now considers the growth of black holes (BHs) as driven by (i) gas accretion during merger-driven starbursts and mergers with other BHs, (ii) accretion during starbursts triggered by disc instabilities, and (iii) accretion of gas cooled from quasi-hydrostatic hot gas haloes. It is assumed that feedback from AGN operates in the later case. The model has been calibrated in order to reproduce observational correlations between BH mass and mass, velocity dispersion, and absolute magnitudes of the galaxy bulge. AGN feedback has a strong impact on reducing or even suppressing gas cooling, an effect that becomes important at lower redshifts. This phenomenon helps to reproduce the observed galaxy luminosity function (LF) in the optical and near IR bands at z=0, and the cosmic star formation rate and stellar mass functions over a wide redshift range (0 1, which are mostly early-type and have older and redder stellar populations than lower mass galaxies, reproducing the observed bimodality in the galaxy colour distribution, and the morphological fractions. The evolution of the optical QSO LF is also reproduced, provided that the presence of a significant fraction of obscured QSOs is assumed. We explore the effects of AGN feedback during starbursts and new recent prescriptions for dynamical friction time-scales. (ABRIDGED)

131 citations

Journal ArticleDOI
01 Oct 2007-Geology
TL;DR: In this paper, the authors report new, unbiased collections of 2516 compression specimens from the Paleocene Salamanca Formation (ca. 61.7 Ma) from two localities in the Palacio de los Loros exposures in southern Chubut, Patagonia, Argentina.
Abstract: Few South American macrofloras of Paleocene age are known, and this limits our knowledge of diversity and composition between the end-Cretaceous event and the Eocene appearance of high floral diversity. We report new, unbiased collections of 2516 compression specimens from the Paleocene Salamanca Formation (ca. 61.7 Ma) from two localities in the Palacio de los Loros exposures in southern Chubut, Patagonia, Argentina. Our samples reveal considerably greater richness than was previously known from the Paleocene of Patagonia, including 36 species of angiosperm leaves as well as angiosperm fruits, flowers, and seeds; ferns; and conifer leaves, cones, and seeds. The floras, which are from siltstone and sandstone channel-fills deposited on low-relief floodplain landscapes in a humid, warm temperate climate, are climatically and paleoenvironmentally comparable to many quantitatively collected Paleocene floras from the Western Interior of North America. Adjusted for sample size, there are >50% more species at each Palacio de los Loros quarry than in any comparable U.S. Paleocene sample. These results indicate more vibrant terrestrial ecosystems in Patagonian than in North American floodplain environments ∼4 m.y. after the end-Cretaceous extinction, and they push back the time line 10 m.y. for the evolution of high floral diversity in South America. The cause of the dis parity is unknown but could involve reduced impact effects because of greater distance from the Chicxulub site, higher latest Cretaceous diversity, or faster recovery or immigration rates.

131 citations

Journal ArticleDOI
Georges Aad1, Brad Abbott2, J. Abdallah3, A. A. Abdelalim4  +3098 moreInstitutions (189)
TL;DR: In this paper, the authors used a minimum bias trigger to select proton-proton collisions at center-of-mass energies of 900 GeV and 7 TeV at the LHC.
Abstract: Measurements of charged particle distributions, sensitive to the underlying event, have been performed with the ATLAS detector at the LHC. The measurements are based on data collected using a minimum-bias trigger to select proton-proton collisions at center-of-mass energies of 900 GeV and 7 TeV. The "underlying event" is defined as those aspects of a hadronic interaction attributed not to the hard scattering process, but rather to the accompanying interactions of the rest of the proton. Three regions are defined in azimuthal angle with respect to the highest transverse momentum charged particle in the event, such that the region transverse to the dominant momentum-flow is most sensitive to the underlying event. In each of these regions, distributions of the charged particle multiplicity, transverse momentum density, and average pT are measured. The data show generally higher underlying event activity than that predicted by Monte Carlo models tuned to pre-LHC data.

131 citations

Journal ArticleDOI
Georges Aad1, Brad Abbott2, Jalal Abdallah3, S. Abdel Khalek4  +2817 moreInstitutions (207)
TL;DR: In this paper, the nuclear modification factors R-AA and R-CP are presented in detail as a function of centrality, p(T) and eta, which is determined by the response of the forward calorimeters located on both sides of the interaction point.
Abstract: Charged-particle spectra obtained in Pb+Pb interactions at root s(NN) = 2.76TeV and pp interactions at root s(NN) = 2.76TeV with the ATLAS detector at the LHC are presented, using data with integrated luminosities of 0.15 nb(-1) and 4.2 pb(-1), respectively, in a wide transverse momentum (0.5 < p(T) < 150 GeV) and pseudorapidity (vertical bar eta vertical bar < 2) range. For Pb+Pb collisions, the spectra are presented as a function of collision centrality, which is determined by the response of the forward calorimeters located on both sides of the interaction point. The nuclear modification factors R-AA and R-CP are presented in detail as a function of centrality, p(T) and eta. They show a distinct p(T)-dependence with a pronounced minimum at about 7 GeV. Above 60 GeV, R-AA is consistent with a plateau at a centrality-dependent value, within the uncertainties. The value is 0.55 +/- 0.01(stat.) +/- 0.04(syst.) in the most central collisions. The R-AA distribution is consistent with flat vertical bar eta vertical bar dependence over the whole transverse momentum range in all centrality classes.

131 citations


Authors

Showing all 13198 results

NameH-indexPapersCitations
David Cameron1541586126067
Subir Sarkar1491542144614
Mayda Velasco137130987579
Diego F. Torres13794872180
Heidi Sandaker12899976517
Vincent Garonne12892176980
Farid Ould-Saada12893176394
Ole Røhne128103875752
Peter Hansen128127186210
Maria-Teresa Dova12777873558
Vladimir Sulin12788475329
Andrei Snesarev12787574907
James Catmore12789275086
Ruslan Mashinistov12686073897
Fernando Monticelli12684373385
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202333
2022315
20211,491
20201,738
20191,675
20181,527