National Autonomous University of Mexico

About: National Autonomous University of Mexico is a education organization based out in Mexico City, Distrito Federal, Mexico. It is known for research contribution in the topics: Population & Galaxy. The organization has 72868 authors who have published 127797 publications receiving 2285543 citations. The organization is also known as: UNAM & Universidad Nacional Autónoma de México.

Charge separation relative to the reaction plane in Pb-Pb collisions at sNN−−−−√=2.76 TeV

Abstract: Measurements of charge-dependent azimuthal correlations with the ALICE detector at the LHC are reported for Pb-Pb collisions at root s(NN) = 2.76 TeV. Two- and three-particle charge-dependent azimuthal correlations in the pseudorapidity range vertical bar eta vertical bar < 0.8 are presented as a function of the collision centrality, particle separation in pseudorapidity, and transverse momentum. A clear signal compatible with a charge-dependent separation relative to the reaction plane is observed, which shows little or no collision energy dependence when compared to measurements at RHIC energies. This provides a new insight for understanding the nature of the charge-dependent azimuthal correlations observed at RHIC and LHC energies. DOI: 10.1103/PhysRevLett.110.012301

Demographic trends in the Cactaceae

Abstract: I. Abstract Although our biological knowledge regarding cactus species is thorough in many areas, only in recent years have ecologists addressed their demographic behavior. Here we attempt a first review of the present knowledge on cactus demography, including an analysis of the published information on species with different growth forms and life-history traits. Our review shows that cactus distribution ranges are determined by environmental heterogeneity and by species-specific physiological requirements. Temperature extremes may pose latitudinal and altitudinal distribution limits. At a more local scale, soil properties dramatically affect cactus distribution. Most cacti show a clumped spatial distribution pattern, which may be the reflection of a patchy resource distribution within their heterogeneous environments. The association of cacti with nurse plants is another factor that may account for this aggregated distribution. Many cacti grow in association with these perennial nurse plants, particularl...

Modern quaternary plant lineages promote diversity through facilitation of ancient tertiary lineages

Abstract: One of the most important floristic sorting periods to affect modern plant communities occurred during the shift from the wet Tertiary period to the unusually dry Quaternary, when most global deserts developed. During this time, a wave of new plant species emerged, presumably in response to the new climate. Interestingly, most Tertiary species that have been tracked through the fossil record did not disappear but remained relatively abundant despite the development of a much more unfavorable climate for species adapted to moist conditions. Here we find, by integrating paleobotanical, ecological, and phylogenetic analyses, that a large number of ancient Tertiary species in Mediterranean-climate ecosystems appear to have been preserved by the facilitative or “nurse” effects of modern Quaternary species. Our results indicate that these interdependent relationships among plants have played a central role in the preservation of the global biodiversity and provided a mechanism for stabilizing selection and the conservation of ecological traits over evolutionary time scales.