Five Younger Dryas black mats in Mexico and their stratigraphic and paleoenvironmental context

The Younger Dryas interval (YD) was a period of widespread, abrupt climate change that occurred between 12,900 and 11,700 cal yr BP (10,900–10,000 14 C BP). Many sites in the Northern Hemisphere preserve a sedimentary record across the onset of the YD interval, including sites investigated in sedimentary basins located in central Mexico (Chapala, Cuitzeo, Acambay), the Basin of Mexico (Tocuila), and northern Mexico (El Cedral). Deposits consist of lacustrine or marginal lake sediments that were deposited during the Pleistocene and the Holocene. At the Tocuila and Acambay sites, Pleistocene fossil vertebrate assemblages, mainly mammoths (Mammuthus columbi), are found in association with a distinctive organic layer, sometimes called the black mat that formed during the YD. At the Chapala, Cuitzeo, Acambay, and Tocuila sites the black mats contain a suite of distinctive microscopic and mineralogical signatures and are accompanied by a sharp change in the depositional environments as supported by diatom and pollen studies reported here. The signatures include magnetic, Fe-rich microspherules, silica melted droplets with aerodynamic shapes (tektites), large amounts of charcoal, and sometimes nanodiamonds (Cuitzeo), all of which were deposited at the onset of the YD. The geochemistry of the microspherules indicates that they are not anthropogenic, authigenic or of cosmic or volcanic origin, and instead, were produced by melting and quenching of terrestrial sediments. Here, we present the stratigraphy at five field sites, the analyses of magnetic microspherules, including major element composition and scanning electron microscopy images. All of these materials are associated with charcoal and soot, which are distinctive stratigraphic markers for the YD layer at several sites in Mexico. © 2017 Springer Science+Business Media B.V

Offset-compensated comparator with full-input range in 150nm FDSOI CMOS-3d technology

Trabajo presentado al LASCAS celebrado en Iguazu (Brasil) del 24 al 26 de febrero de 2010.This paper addresses an offset-compensated comparator with full-input range in the 150nm FDSOI CMOS-3D technology from MIT- Lincoln Laboratory. The comparator discussed here makes part of a vision system. Its architecture is that of a self-biased inverter with dynamic offset correction. At simulation level, the comparator can reach a resolution of 0.1mV in an area of approximately 220μm2 with a time response of less than 40ns and a static power dissipation of 1.125μW.Peer Reviewe

Information theory in the study of anisotropic radiation

Information theory is used to perform a thermodynamic study of non equilibrium anisotropic radiation. We limit our analysis to a second-order truncation of the moments, obtaining a distribution function which leads to a natural closure of the hierarchy of radiative transfer equations in the so-called variable Eddington factor scheme. Some Eddington factors appearing in the literature can be recovered as particular cases of our two-parameter Eddington factor. We focus our attention in the study of the thermodynamic properties of such systems and relate it to recent nonequilibrium thermodynamic theories. Finally we comment the possibility of introducing a nonequilibrium chemical potential for photons.Comment: 1 eps figure upon request by e-mail, to appear in Journal of Physics

Escenario de investigación.

Dentro del Programa de Aplicación Profesional de Clínica de Derecho y Gestión Ambiental el escenario de investigación tuvo como objetivo dar continuidad a los procesos de investigación, asesoría y servicio público iniciados por el PAP, así como, proporcionar información necesaria a los distintos escenarios del PAP para reconocer, analizar y cuestionar los resultados en el cumplimiento de las atribuciones gubernamentales en materia ambiental. La metodología del escenario de investigación durante el presente semestre, fue buscar información en fuentes confiables de los datos reportados de estudios previamente aplicados y basado en las Normas Oficiales Mexicanas. El primer análisis técnico realizado, fue para respaldar la situación en la que se encuentra la comunidad de Mezcala debido a la contaminación de los mantos acuíferos de los que se obtiene este recurso para suministrarlo a la comunidad. La metodología para la justificación técnica consistió en solicitar por medio de transparencia al Ayuntamiento Constitucional de Poncitlán y la Comisión Estatal del Agua de Jalisco copias simples de los certificados analíticos de pruebas realizadas al agua de uso de la comunidad. Una vez obtenida la información se determinaron de acuerdo a la NOM-127-SSA1-1994 si los resultados reportados entraban dentro de los parámetros oficiales establecidos para un buen control de calidad cuyos resultados se muestran en el siguiente apartado. En los próximos apartados se muestran los resultados obtenidos para presentar las consecuencias que existen debido al incumplimiento de la Norma Oficial Mexicana NOM-083-SEMARNAT-2003, Especificaciones de protección ambiental para la selección del sitio, diseño, construcción, operación, monitoreo, clausura y obras complementarias de un sitio de disposición final de residuos sólidos urbanos y de manejo especial.ITESO, A.C

Population genomics applications for conservation: the case of the tropical dry forest dweller Peromyscus melanophrys

Recent advances in genomic sequencing have opened new horizons in the study of population genetics and evolution in non-model organisms. However, very few population genomic studies have been performed on wild mammals to understand how the landscape affects the genetic structure of populations, useful information for the conservation of biodiversity. Here, we applied a genomic approach to evaluate the relationship between habitat features and genetic patterns at spatial and temporal scales in an endangered ecosystem, the Tropical Dry Forest (TDF). We studied populations of the Plateau deer mouse Peromyscus melanophrys to analyse its genomic diversity and structure in a TDF protected area in the Huautla Mountain Range (HMR), Mexico based on 8,209 SNPs obtained through Genotyping-by-Sequencing. At a spatial scale, we found a significant signature of isolation-by-distance, few significant differences in genetic diversity indices among study sites, and no significant differences between habitats with different levels of human perturbation. At a temporal scale, while genetic diversity levels fluctuated significantly over time, neither seasonality nor disturbance levels had a significant effect. Also, outlier analysis revealed loci potentially under selection. Our results suggest that the population genetics of P. melanophrys may be little impacted by anthropogenic disturbances, or by natural spatial and temporal habitat heterogeneity in our study area. The genome-wide approach adopted here provides data of value for conservation planning, and a baseline to be used as a reference for future studies on the effects of habitat fragmentation and seasonality in the HMR and in TDF

35th International Cosmic Ray Conference, ICRC 2017

The extragalactic background light (EBL) is the radiation accumulated through the history of the Universe in the wavelength range from the ultraviolet to the far infrared. Local foregrounds make the direct measurement of the diffuse EBL notoriously difficult, while robust lower limits have been obtained by adding up the contributions of all the discrete sources resolved in deep infrared and optical galaxy observations. Gamma-ray astronomy has emerged in the past few years as a powerful tool for the study of the EBL: very-high-energy (VHE) photons traversing cosmological distances can interact with EBL photons to produce e+e- pairs, resulting in an energy-dependent depletion of the gamma-ray flux of distant sources that can be used to set constraints on the EBL density. The study of the EBL is one of the key scientific programs currently carried out by the MAGIC collaboration. We present here the results of the analysis of 32 VHE spectra of 12 blazars in the redshift range 0.03-0.94, obtained with over 300 hours of observations with the MAGIC telescopes between 2010 and 2016. A combined likelihood maximization approach is used to evaluate the density and spectrum of the EBL most consistent with the MAGIC observations. The results are compatible with state-of-the-art EBL models, and constrain the EBL density to be within ≈ 20% the nominal value in such models. The study reveals no anomalies in gamma-ray propagation in the large optical depth regime - contrary to some claims based on meta-analyses of published VHE spectra.</p

Multiparticle Biased DLA with surface diffusion: a comprehensive model of electrodeposition

We present a complete study of the Multiparticle Biased Diffusion-Limited Aggregation (MBDLA) model supplemented with surface difussion (SD), focusing on the relevance and effects of the latter transport mechanism. By comparing different algorithms, we show that MBDLA+SD is a very good qualitative model for electrodeposition in practically all the range of current intensities {\em provided} one introduces SD in the model in the proper fashion: We have found that the correct procedure involves simultaneous bulk diffusion and SD, introducing a time scale arising from the ratio of the rates of both processes. We discuss in detail the different morphologies obtained and compare them to the available experimental data with very satisfactory results. We also characterize the aggregates thus obtained by means of the dynamic scaling exponents of the interface height, allowing us to distinguish several regimes in the mentioned interface growth. Our asymptotic scaling exponents are again in good agreement with recent experiments. We conclude by discussing a global picture of the influence and consequences of SD in electrodeposition.Comment: 15 pages, 20 figures, accepted for publication in Physical Review

Medios de comunicación y derecho a la información en Jalisco 2013

En el primer apartado, dedicado al sistema de medios en general, se presentan tres artículos: “Nuevos medios de comunicación en Jalisco”, “c7 ¿medio público o vocero del gobierno?” y “Réquiem por un ombudsman”. El segundo apartado está dedicado al tema de la libertad de expresión; se presentan aquí dos textos: “La vulnerabilidad en un ambiente de cambio. Los ataques a los medios de comunicación en Jalisco durante el año” y “Violaciones a la libertad de expresión de periodistas y trabajadores de medios en Jalisco, 1995-2013”. En el apartado “Derecho a la información, comunicación y política” se ofrecen cuatro textos de índole muy diversa: “La estrategia de comunicación del Gobierno del Estado”, “Diálogos públicos: la discusión de una nueva ley de transparencia para Jalisco”, “Cuando un niño desaparece, el peor enemigo es el tiempo…”, sobre la alerta Amber, y “2013: un año marcado por despidos en diversos periódicos de Guadalajara”. En la sección “Los que se fueron” se presenta la semblanza de Felipe Vicencio. Y en el apartado de “La investigación del observatorio de medios” se comparten los resultados de un trabajo sobre los columnistas de opinión jaliscienses que escriben en la prensa local.ITESO, A.C

Keys to the success of the CB Conquero

Cuando un club consigue éxitos deportivos a nivel profesional, existe un gran interés por investigar cuales han sido los factores claves de ese éxito. En esta investigación, se pretende analizar la influencia de diferentes factores como el contexto deportivo, el contexto social y aspectos del entrenamiento deportivo en el éxito del Club Baloncesto Conquero a través de la percepción de 13 informantes clave por su vinculación con el equipo y con el baloncesto onubense. Se realizó una entrevista, relacionada con los factores y las claves del éxito. Los resultados mostraron que la planificación de la plantilla junto al gran trabajo del cuerpo técnico, cuerpo médico y el preparador físico han sido las claves para que el club obtuviera los éxitos deportivos.When a team gets sport successes to level profesional, generates the topics that will be investigated such as the key factors of the succes. The main aim of this study is to analyze the influencie of different factors like the sports context, the social context and training aspects in the success of the Club Baloncesto Conquero through direct perception of thirteen informants associated with the team and the basketball in Huelva. An interview was carried out, related with those factors and the keys to success. The results revealed that workforce planning along the great work of coaching staff, medical staff and physical trainer have been key to the team gets sport successes