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

TRACE ELEMENTS IN SHEEP AND GOATS REPRODUCTION: A REVIEW

The reproduction of small ruminants like goats and sheep managed under extensive range grazing conditions can be affected by nutrients availability and especially by the mineral content of the forages resources on the rangeland. It has been particularly demonstrated that trace elements can have equally, beneficial or detrimental effects, depending on its balance, on reproductive functions in small ruminants. Trace elements as copper, molybdenum, selenium and zinc play key role on the metabolism of carbohydrates, proteins and lipids; however, the mode of action by which these elements affect reproduction in sheep and goats are not completely understood, due to the complexity in the mode of action of the metallobiomolecules and the neuro-hormonal relationship. In this way, their absence or presence of these minerals in several organs, fluids, or tissues of the reproductive tract have allowed obtaining information on the metabolism and the role of these elements on reproduction in sheep and goats. On this regard, the objective of this document is to review the relationships and effects of some trace elements, on reproductive events in sheep and goats

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

EFFECT OF SEASON ON SERUM COPPER AND ZINC CONCENTRATIONS IN CROSSBRED GOATS HAVING DIFFERENT REPRODUCTIVE STATUS UNDER SEMIARID RANGELAND CONDITIONS IN SOUTHERN MEXICO STATE

The effect of season (rainy: RS, and dry: DS) and reproductive status on copper (Cu) and zinc (Zn) concentrations in blood serum of crossbred goats (BW= 36.01 ± 1.59 kg) were studied under semiarid rangeland conditions in Southern Mexico State. Blood samples from 80 crossbred goats were taken each season (RS and DS). The goats were clustered into 10 different groups considering their reproductive status. Concentrations of Cu and Zn in serum were assayed using atomic absorption. Data were analyzed using a general linear model procedure for a completely randomized design and differences among means were examined using a Tukey test. Blood serum concentrations of Cu and Zn were affected by reproductive status and season (P<0.001). In relation to the season, Cu and Zn serum levels were lower in RS than DS (P<0.05). Overall, kidded goats had the highest values (P<0.01) for Cu than other animals in both seasons (RS or DS). Anestrous goats had the lowest concentrations (P<0.01) for Zn during RS, while all goats at their second or more kidding, rearing single or twins, showed the highest concentrations of Zn (P<0.001) in this season. Adult goats in Southern Mexico State showed a deficiency of Cu and Zn, especially during RS. As such, mineral supplements should be provided with respect to these elements in feeding systems for goats under semiarid rangeland conditions in order to evaluate their impact on health and reproduction

Spatial and temporal distribution of Mycobacterium tuberculosis complex infection in Eurasian badger (Meles meles) and cattle in Asturias, Spain

Trabajo presentado al: 69th Wildlife Disease Association and 14th European Wildlife Disease Association Conference. Cuenca, Spain. p. 66. 31 agosto-2 septiembre

Modelización del arrastre del mobiliario urbano durante eventos extremos de inundaciones

Web da Revista Avances en Ciencias de la Tierra (ACT): https://ephyslab.uvigo.es/revista-act/[Resumen:] El código DualSPHysics, basado en la metodología SPH, se utilizó en este trabajo para modelar el arrastre de mobiliario urbano (coches, contenedores, etc.) durante inundaciones. Primero se validó el modelo DualSPHysics simulando el avance de una masa de agua, su interacción con diferentes objetos y el arrastre de los mismos. Para ello se compararon datos experimentales con los resultados de simulaciones numéricas, obteniendo valores muy similares para las posiciones de avance de varios objetos flotantes y para alturas de superficie de agua. Una vez validada la herramienta numérica, se utilizó DualSPHysics para simular un caso real en la ciudad de Lugo; donde se simuló una crecida del rio Miño y la consiguiente inundación de un aparcamiento. En este caso de aplicación se analizó el desplazamiento de algunos coches allí aparcados y la altura que alcanzó la capa de agua en diferentes puntos del aparcamiento

New records of ray-finned fishes (Actinopterygii) from Puerto Morelos Reef National Park (Mexican Caribbean)

We documented the nearshore ray-finned fishes in Puerto Morelos Reef National Park (PMRNP) by sampling 57 localities, including rocky intertidal pools, sandy bottoms, Thalassia beds, coral reefs, artificial reefs, karstic-slab bottoms, demersal-pelagic areas, and sessile-Sargassum patches. We recorded seven species new to Caribbean Mexican waters and one hundred and six species new to the PMRNP, most of which are small cryptobenthic reef fish. The resultant checklist includes 349 species, and specimens of 285 of which (81.7%) have been deposited in an ichthyological museum collection. These include both voucher organisms and with tissue samples for genetic analysis. A comparison with inventories at other localities of the Greater Caribbean indicates that more targeted sampling for cryptobenthic and deep-reef fishes is needed to provide a complete inventory. We also comment on the local use of some species as fishery resources

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

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