The Younger Dryas black mat from Ojo de Agua, a geoarchaeologicalsite in Northeastern Zacatecas, Mexico

New explorations in the desert of northeastern Zacatecas, in central-northern Mexico, revealed dozens ofarchaeological and geoarchaeological sites. One of them, Ojo de Agua, contains the remains of a Pleis-tocene spring-fed hydrographic system located at the southeastern end of a large elongated endorheicbasin. The locality yielded a particularly dark, highly organic stratigraphic layer commonly known in theAmericas as Black Mat (BM), exposed on the natural profiles of a creek, but not associated with culturalmaterials. Several radiocarbon assessments confirmed the formation of the Ojo de Agua Black Mat duringthe Younger Dryas chronozone, with ten calibrated results clustering between 12,700e12,100 cal BP. Thismulti-proxy study confirmed the peculiarity of the deposit and found similarities and differences withother contexts of Younger Dryas age. The Ojo de Agua Black Mat (stratum C2) is far richer in charcoalspecks than the related strata, but lacks phytoliths, diatoms or ostracods. No further biological remainswere found in it, except for intrusive capillary roots. Clearly water-lain in a shallow pond, the stratumqualifies as a clayey silt with an acidic-to-neutral pH. Rich in heavy metals and with high contents oftitanium, the Ojo de Agua Black Mat yielded significant indicators of intense wildfires during the YoungerDryas, but produced no carbon spherules or nanodiamonds supposedly linked to the impact theory

BIM en la construcción

244 páginas.En la actualidad, con la metodología BIM (Building Information Modeling), todos los sistemas de información de los procesos productivos en la obra se han integrado, la información se puede compartir a distancia y en tiempo real con todos los actores involucrados en el proyecto. En estas condiciones, las instituciones generadoras de obras y las empresas prestadoras de servicios se están rediseñando con nuevos modelos de negocios enfocados en satisfacer las actuales demandas y experiencias de los clientes. El libro que aquí se presenta reúne el trabajo de investigación referente a BIM de la Red Académica de Diseño Construcción integrada por académicos de la Facultad de Ingeniería de la Universidad Autónoma de Yucatán, México (UADY), el Worcester Polytechnical Institute (WPI) de Massachusetts, Estados Unidos y del Área de Administración y Tecnología para el Diseño de la Universidad Autónoma Metropolitana, Unidad Azcapotzalco (UAM). También han colaborado con la Red investigadores de la Universidad Politécnica de Madrid (UPM), España y, dentro de la UAM, académicos de la División de Ciencias Básicas e Ingeniería, Departamento de Materiales, del Área de Construcción. Cabe mencionar que los artículos ya han sido publicados con anterioridad en los Anuarios de Administración y Tecnología para el Diseño y las Compilaciones de Artículos de Investigación en Administración y Tecnología para la Arquitectura, Diseño e Ingeniería, productos del trabajo de investigación del Área que edita anualmente desde 1999, como se indica en el índice del presente libro

Gestión del conocimiento. Perspectiva multidisciplinaria. Volumen 10

El libro “Gestión del Conocimiento. Perspectiva Multidisciplinaria”, Volumen 10, de la Colección Unión Global, es resultado de investigaciones. Los capítulos del libro, son resultados de investigaciones desarrolladas por sus autores. El libro es una publicación internacional, seriada, continua, arbitrada de acceso abierto a todas las áreas del conocimiento, que cuenta con el esfuerzo de investigadores de varios países del mundo, orientada a contribuir con procesos de gestión del conocimiento científico, tecnológico y humanístico que consoliden la transformación del conocimiento en diferentes escenarios, tanto organizacionales como universitarios, para el desarrollo de habilidades cognitivas del quehacer diario. La gestión del conocimiento es un camino para consolidar una plataforma en las empresas públicas o privadas, entidades educativas, organizaciones no gubernamentales, ya sea generando políticas para todas las jerarquías o un modelo de gestión para la administración, donde es fundamental articular el conocimiento, los trabajadores, directivos, el espacio de trabajo, hacia la creación de ambientes propicios para el desarrollo integral de las instituciones

Multi-messenger Observations of a Binary Neutron Star Merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ∼ 1.7 {{s}} with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of {40}-8+8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 {M}ȯ . An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ∼ 40 {{Mpc}}) less than 11 hours after the merger by the One-Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ∼10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ∼ 9 and ∼ 16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC 4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta.</p

Efectos ambientales del drenaje ácido de mina y su tratamiento

La minería es una actividad industrial de gran importancia para el desarrollo científico, tecnológico, arquitectura, salud y telecomunicaciones. México es caracterizado por su riqueza de especies minerales que alberga su diversidad geológica, que promueve gran interés entre compañías mineras nacionales e internacionales (Ramírez Macedonio &amp; García Castro, 2020). Por otro lado, la minería genera grandes cantidades de desechos que no son tratados y provocan graves problemas ambientales (Mafra et al., 2020). El Drenaje Ácido de Mina (DAM) resulta de la oxidación química y bacteriana de minerales sulfurados como la pirita (FeS2), en condiciones atmosféricas durante la extracción de minerales metálicos y carbón. El impacto adverso que causa el DAM sobre la vida acuática y la calidad de los cuerpos de agua es preocupante debido a la movilidad de ácidos, sulfatos y metales (Fe, Al, Mn, Zn, Cu, Pb, Hg, Cd, Ni), metaloides (As) y sólidos en suspensión (Akcil &amp; Koldas, 2006; Alonso et al., 2020; Kefeni et al., 2018; Nqombolo et al., 2019; Rodríguez-Galán et al., 2019); esta contaminación es un problema global debido a su toxicidad y bioacumulación (Atangana &amp; Oberholster, 2021; Ayala &amp; Fernández, 2019; Pan et al., 2021; Sahoo et al., 2020). El objetivo de este trabajo es analizar los impactos del DAM, los avances y las propuestas para su manejo, tratamiento y mitigación

Multi-messenger Observations of a Binary Neutron Star Merger

International audienceOn 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of $\sim 1.7\,{\rm{s}}$ with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg(2) at a luminosity distance of ${40}_{-8}^{+8}$ Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 $\,{M}_{\odot }$. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at $\sim 40\,{\rm{Mpc}}$) less than 11 hours after the merger by the One-Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ∼10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position $\sim 9$ and $\sim 16$ days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC 4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Search for multimessenger sources of gravitational waves and high-energy neutrinos with Advanced LIGO during its first observing run, ANTARES, and IceCube

Astrophysical sources of gravitational waves, such as binary neutron star and black hole mergers or core-collapse supernovae, can drive relativistic outflows, giving rise to non-thermal high-energy emission. High-energy neutrinos are signatures of such outflows. The detection of gravitational waves and high-energy neutrinos from common sources could help establish the connection between the dynamics of the progenitor and the properties of the outflow. We searched for associated emission of gravitational waves and high-energy neutrinos from astrophysical transients with minimal assumptions using data from Advanced LIGO from its first observing run O1, and data from the Antares and IceCube neutrino observatories from the same time period. We focused on candidate events whose astrophysical origins could not be determined from a single messenger. We found no significant coincident candidate, which we used to constrain the rate density of astrophysical sources dependent on their gravitational-wave and neutrino emission processes