Instituto Politécnico Nacional

About: Instituto Politécnico Nacional is a education organization based out in Mexico City, Mexico. It is known for research contribution in the topics: Population & Context (language use). The organization has 43351 authors who have published 63315 publications receiving 938532 citations. The organization is also known as: Instituto Politécnico Nacional & Instituto Politecnico Nacional.

Gaia Early Data Release 3 - The Gaia Catalogue of Nearby Stars

Abstract: Aims. We produce a clean and well-characterised catalogue of objects within 100 pc of the Sun from the Gaia Early Data Release 3. We characterise the catalogue through comparisons to the full data release, external catalogues, and simulations. We carry out a first analysis of the science that is possible with this sample to demonstrate its potential and best practices for its use.Methods. Theselection of objects within 100 pc from the full catalogue used selected training sets, machine-learning procedures, astrometric quantities, and solution quality indicators to determine a probability that the astrometric solution is reliable. The training set construction exploited the astrometric data, quality flags, and external photometry. For all candidates we calculated distance posterior probability densities using Bayesian procedures and mock catalogues to define priors. Any object with reliable astrometry and a non-zero probability of being within 100 pc is included in the catalogue.Results. We have produced a catalogue of 331 312 objects that we estimate contains at least 92% of stars of stellar type M9 within 100 pc of the Sun. We estimate that 9% of the stars in this catalogue probably lie outside 100 pc, but when the distance probability function is used, a correct treatment of this contamination is possible. We produced luminosity functions with a high signal-to-noise ratio for the main-sequence stars, giants, and white dwarfs. We examined in detail the Hyades cluster, the white dwarf population, and wide-binary systems and produced candidate lists for all three samples. We detected local manifestations of several streams, superclusters, and halo objects, in which we identified 12 members of Gaia Enceladus. We present the first direct parallaxes of five objects in multiple systems within 10 pc of the Sun.Conclusions. We provide the community with a large, well-characterised catalogue of objects in the solar neighbourhood. This is a primary benchmark for measuring and understanding fundamental parameters and descriptive functions in astronomy.

Multiple Galactic Sources with Emission Above 56 TeV Detected by HAWC

Abstract: We present the first catalog of gamma-ray sources emitting above 56 and 100 TeV with data from the High Altitude Water Cherenkov Observatory, a wide field-of-view observatory capable of detecting gamma rays up to a few hundred TeV. Nine sources are observed above 56 TeV, all of which are likely galactic in origin. Three sources continue emitting past 100 TeV, making this the highest-energy gamma-ray source catalog to date. We report the integral flux of each of these objects. We also report spectra for three highest-energy sources and discuss the possibility that they are PeVatrons.

Non-stationary frequency analysis of extreme daily rainfall in Sao Paulo, Brazil

Abstract: This work is an assessment of frequency of extreme values (EVs) of daily rainfall in the city of Sao Paulo, Brazil, over the period 1933–2005, based on the peaks-over-threshold (POT) and Generalized Pareto Distribution (GPD) approach. Usually, a GPD model is fitted to a sample of POT values selected with a constant threshold. However, in this work we use time-dependent thresholds, composed of relatively large p quantiles (for example p of 0.97) of daily rainfall amounts computed from all available data. Samples of POT values were extracted with several values of p. Four different GPD models (GPD-1, GPD-2, GPD-3, and GDP-4) were fitted to each one of these samples by the maximum likelihood (ML) method. The shape parameter was assumed constant for the four models, but time-varying covariates were incorporated into scale parameter of GPD-2, GPD-3, and GPD-4, describing annual cycle in GPD-2, linear trend in GPD-3, and both annual cycle and linear trend in GPD-4. The GPD-1 with constant scale and shape parameters is the simplest model. For identification of the best model among the four models we used rescaled Akaike Information Criterion (AIC) with second-order bias correction. This criterion isolates GPD-3 as the best model, i.e. the one with positive linear trend in the scale parameter. The slope of this trend is significant compared to the null hypothesis of no trend, for about 98% confidence level. The non-parametric Mann–Kendall test also showed presence of positive trend in the annual frequency of excess over high thresholds, with p-value being virtually zero. Therefore, there is strong evidence that high quantiles of daily rainfall in the city of Sao Paulo have been increasing in magnitude and frequency over time. For example, 0.99 quantiles of daily rainfall amount have increased by about 40 mm between 1933 and 2005. Copyright © 2008 Royal Meteorological Society

MicroRNA expression profile in endometriosis: its relation to angiogenesis and fibrinolytic factors

Abstract: Study question Could an aberrant microRNA (miRNA) expression profile be responsible for the changes in the angiogenic and fibrinolytic states observed in endometriotic lesions? Summary answer This study revealed characteristic miRNA expression profiles associated with endometriosis in endometrial tissue and endometriotic lesions from the same patient and their correlation with the most important angiogenic and fibrinolytic factors. WHAT IS ALREADY KNOWN?: An important role for dysregulated miRNA expression in the pathogenesis of endometriosis is well documented. However, to the best of our knowledge, there are no reports of the relationship between angiogenic and fibrinolytic factors and miRNAs when endometrial tissue and different types of endometriotic lesions from the same patient are compared. Study design, size, duration Case-control study that involved 51 women with endometriosis and 32 women without the disease (controls). Participants/materials, setting, methods The miRNA expression profiles were determined using the GeneChip miRNA 2.0 Affymetrix array platform, and the results were analysed using Partek Genomic Suite software. To validate the obtained results, 12 miRNAs differentially expressed were quantified by using miRCURY LNA™ Universal RT microRNA PCR. Levels of vascular endothelial growth factor (VEGF-A), thrombospondin-1 (TSP-1), urokinase plasminogen activator (uPA) and plasminogen activator inhibitor-1 (PAI-1) proteins were quantified by ELISA. Main results and the role of chance Patient endometrial tissue showed significantly lower levels of miR-202-3p, miR-424-5p, miR-449b-3p and miR-556-3p, and higher levels of VEGF-A and uPA than healthy (control) endometrium. However, tissue affected by ovarian endometrioma showed significantly lower expression of miR-449b-3p than endometrium from both controls and patients, and higher levels of PAI-1 and the angiogenic inhibitor TSP-1. A significant inverse correlation between miR-424-5p and VEGF-A protein levels was observed in patient endometrium, and an inverse correlation between miR-449b-3p and TSP-1 protein levels was observed in ovarian endometrioma. Peritoneal implants had significantly higher levels of VEGF-A than ovarian endometrioma samples. Limitations, reasons for caution Functional studies are needed to confirm the specific targets of the miRNAs differently expressed. Wider implications of the findings Differences in miRNA levels could modulate the expression of VEGF-A and TSP-1, which may play an important role in the pathogenesis of endometriosis. The higher angiogenic and proteolytic activities observed in eutopic endometrium from patients might facilitate the implantation of endometrial cells at ectopic sites. Study funding/competing interest(s) This work was supported by research grants from ISCIII-FEDER (PI11/0091, Red RIC RD12/0042/0029), Conselleria de Educacion-Generalitat Valenciana (PROMETEO/2011/027), Beca de Investigacion Fundacion Dexeus para la Salud de la Mujer (2011/0469), and by Fundacion Investigacion Hospital La Fe (2011/211). A.B-B. has a Contrato Posdoctoral de Perfeccionamiento Sara Borrell-ISCIII (CD13/00005). J.M-A. has a predoctoral grant PFIS-ISCIII (FI12/00012). The authors have no conflicts of interest to declare.