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.

Matrix Metalloproteases in Aberrant Fibrotic Tissue Remodeling

Abstract: Pulmonary fibrosis, the final result of a large variety of interstitial lung diseases, is characterized by an aberrant remodeling of extracellular matrix (ECM) with a profound disturbance of the normal lung architecture. This remodeling includes the exaggerated accumulation of ECM components in the interstitial and alveolar spaces and the disruption of the basement membranes. It has long been accepted that matrix metalloproteases (MMPs) play an important role in the pathogenesis of pulmonary fibrosis, but the exact mechanisms are not well characterized. Several MMPs are strongly up-regulated in human and experimental lung fibrosis, highlighting the dynamic nature of scarring within the lung. MMPs are collectively capable of cleaving all components of the ECM and basement membranes, but importantly, they also process bioactive mediators such as growth factors, cytokines, chemokines, and cell-surface receptors. Moreover, they participate in the initiation of proteinase cascades that impact much broader substrates. Consequently, MMPs may play a central role in several interrelated processes observed in fibrosis such as ECM remodeling, basement-membrane breakdown, epithelial-cell apoptosis, cell migration, and angiogenesis.

Measurement of the proton-air cross section at √s=57 TeV with the Pierre Auger Observatory.

Abstract: We report a measurement of the proton-air cross section for particle production at the center-of-mass energy per nucleon of 57 TeV. This is derived from the distribution of the depths of shower maxima observed with the Pierre Auger Observatory: systematic uncertainties are studied in detail. Analyzing the tail of the distribution of the shower maxima, a proton-air cross section of [505 +/- 22(stat)(-36)(+28)(syst)] mb is found.

Nd:YAG Near-Infrared Luminescent Nanothermometers

Abstract: Dr. A. Benayas, Prof. F. Vetrone Institut National de la Recherche Scientifi que Centre – Energie Materiaux et Telecommunications 1650, Boul. Lionel Boulet Varennes , QC J3X 1S2 , Canada E-mail: antonio.benayas@emt.inrs.ca B. del Rosal, A. Perez-Delgado, Dr. D. Jaque Fluorescence Imaging GroupDepartamento de Fisica de Materiales Facultad de Ciencias, Universidad Autonoma de Madrid Campus de Cantoblanco Madrid 28049 , Spain Dr. K. Santacruz-Gomez Departamento de Fisica, Universidad de Sonora Rosales y Blvd. Luis Encinas s/n CP 8300 , Hermosillo , Sonora , Mexico Dr. D. Jaque IRYCIS, Instituto Ramon y Cajal de Investigacion Sanitaria. Hospital Ramon y Cajal, 28034 Madrid, Spain Dr. G. A. Hirata Centro de Nanociencias y Nanotecnologia Universidad Nacional Autonoma de Mexico Ensenada , Baja California C.P. 22860 , Mexico

Successional dynamics in Neotropical forests are as uncertain as they are predictable

Abstract: Although forest succession has traditionally been approached as a deterministic process, successional trajectories of vegetation change vary widely, even among nearby stands with similar environmental conditions and disturbance histories. Here, we provide the first attempt, to our knowledge, to quantify predictability and uncertainty during succession based on the most extensive long-term datasets ever assembled for Neotropical forests. We develop a novel approach that integrates deterministic and stochastic components into different candidate models describing the dynamical interactions among three widely used and interrelated forest attributes—stem density, basal area, and species density. Within each of the seven study sites, successional trajectories were highly idiosyncratic, even when controlling for prior land use, environment, and initial conditions in these attributes. Plot factors were far more important than stand age in explaining successional trajectories. For each site, the best-fit model was able to capture the complete set of time series in certain attributes only when both the deterministic and stochastic components were set to similar magnitudes. Surprisingly, predictability of stem density, basal area, and species density did not show consistent trends across attributes, study sites, or land use history, and was independent of plot size and time series length. The model developed here represents the best approach, to date, for characterizing autogenic successional dynamics and demonstrates the low predictability of successional trajectories. These high levels of uncertainty suggest that the impacts of allogenic factors on rates of change during tropical forest succession are far more pervasive than previously thought, challenging the way ecologists view and investigate forest regeneration.