Surficial Geology of the Chicxulub Impact Crater, Yucatan, Mexico

The Chicxulub impact crater in northwestern Yucatan, Mexico is the primary candidate for the proposed impact that caused mass extinctions at the end of the Cretaceous Period. The crater is buried by up to a kilometer of Tertiary sediment and the most prominent surface expression is a ring of sink holes, known locally as cenotes, mapped with Landsat imagery. This 165 +/- 5 km diameter Cenote Ring demarcates a boundary between unfractured limestones inside the ring, and fractured limestones outside. The boundary forms a barrier to lateral ground water migration, resulting in increased flows, dissolution, and collapse thus forming the cenotes. The subsurface geology indicates that the fracturing that created the Cenote Ring is related to slumping in the rim of the buried crater, differential thicknesses in the rocks overlying the crater, or solution collapse within porous impact deposits. The Cenote Ring provides the most accurate position of the Chicxulub crater's center, and the associated faults, fractures, and stratigraphy indicate that the crater may be approx. 240 km in diameter

The problem of endosulfan: chemical, analytical and environmental issues

Introducción. Dado el carácter residual y el alto nivel de toxicidad del endosulfán, se ha incrementado la preocupación a nivel mundial por su impacto ambiental. Por eso la búsqueda de metodologías analíticas que permitan su detección y cuantificación es un tema de investigación vigente. Las propiedades del endosulfán y su patrón de degradación le confieren características que hacen muy compleja la problemática, al tiempo que el pesticida y sus metabolitos se expanden extensivamente por la atmósfera y contaminan tanto matrices lipofílicas como hidrofílicas. Objetivo. Llevar a cabo una revisión sobre las investigaciones más recientes acerca de la problemática del endosulfán, que incluye aspectos químicos, su problemática ambiental y técnicas inmunoquímicas para su análisis, tema en el que ha estado interesado nuestro grupo de investigación en la Universidad de Caldas. Método. El presente artículo de revisión analiza, cualitativamente, la literatura científica disponible en las bases de datos Science Direct, PubMed, Scielo y páginas Web oficiales, empleando como palabras de búsqueda: endosulfán, haptenos, análisis inmunoquímico del endosulfán, problemática ambiental del endosulfán, regulaciones internacionales sobre el endosulfán, normatividad vigente sobre el endosulfán, y métodos instrumentales de análisis. Resultados. Se obtuvo información pertinente relacionada con el objetivo propuesto, la cual se presenta en 3 secciones: aspectos químicos del endosulfán, problemática ambiental y técnicas inmoquímicas para su análisis. Conclusión. El endosulfán ha sido prohibido por los organismos internacionales. Sin embargo, el pesticida se continúa usando en algunos países y éste se difunde fácilmente hacia otras regiones, de tal manera que se ha convertido en un problema global. Hay investigaciones recientes sobre métodos de remediación química o biológica, pero los esfuerzos son modestos frente a la enorme problemática de este pesticida. En lo pertinente a análisis químicos de endosulfán, en los últimos 15 años se han investigado técnicas inmunoquímicas de análisis (basadas en haptenos), como alternativa a los métodos cromatográficos instrumentales.Introduction. Due to the residual character and high level of toxicity of endosulfan, worldwide concern for its environmental impact has increased. Therefore, the search for analytical methodologies that allow its detection and quantification continues to be a topic of current research. Endosulfan properties and its degradation pattern confer it characteristics that make very complex the problematic while the pesticide and its metabolites are extensively spread throughout the atmosphere and contaminate both lipophilic and hydrophilic matrixes. Objective. To conduct a review on some recent research about the endosulfan problematic including chemical aspects, environmental issues and immunochemical techniques for its analysis, which is an area of current interest in this research group at Universidad de Caldas. Method. This review article  analyzes qualitatively scientific literature from ScienceDirect, PubMed, Scielo  databases and official Web pages using key words such as endosulfan, endosulfan immunochemical analysis, endosulfan environmental problematic, endosulfan international regulations, endosulfan current normativity and instrumental methods for the analysis. Results. Relevant information related to the proposed objective was found which is presented in 3 sections: chemical aspects of endosulfan, environmental issues, and immunochemical techniques for its analysis. Conclusions. Endosulfan has been banned by international organizations. However, the pesticide is still being used in some countries and is easily spread to other regions, so that the problem became a global concern. There is some recent research on biological or chemical remediation techniques, but efforts seem insufficient in comparison to the enormous impact of the pesticide. In regard to Endosulfan chemical analyses, during the past 15 years immunochemical haptenbased analysis techniques have been investigated as alternatives to the instrumental chromatographic methods

Size and Shape Constraints of (486958) Arrokoth from Stellar Occultations

We present the results from four stellar occultations by (486958) Arrokoth, the flyby target of the New Horizons extended mission. Three of the four efforts led to positive detections of the body, and all constrained the presence of rings and other debris, finding none. Twenty-five mobile stations were deployed for 2017 June 3 and augmented by fixed telescopes. There were no positive detections from this effort. The event on 2017 July 10 was observed by the Stratospheric Observatory for Infrared Astronomy with one very short chord. Twenty-four deployed stations on 2017 July 17 resulted in five chords that clearly showed a complicated shape consistent with a contact binary with rough dimensions of 20 by 30 km for the overall outline. A visible albedo of 10% was derived from these data. Twenty-two systems were deployed for the fourth event on 2018 August 4 and resulted in two chords. The combination of the occultation data and the flyby results provides a significant refinement of the rotation period, now estimated to be 15.9380 ± 0.0005 hr. The occultation data also provided high-precision astrometric constraints on the position of the object that were crucial for supporting the navigation for the New Horizons flyby. This work demonstrates an effective method for obtaining detailed size and shape information and probing for rings and dust on distant Kuiper Belt objects as well as being an important source of positional data that can aid in spacecraft navigation that is particularly useful for small and distant bodies.Fil: Buie, Marc W.. Southwest Research Institute.; Estados UnidosFil: Porter, Simon B.. Southwest Research Institute.; Estados UnidosFil: Tamblyn, Peter. Southwest Research Institute.; Estados UnidosFil: Terrell, Dirk. Southwest Research Institute.; Estados UnidosFil: Parker, Alex Harrison. Southwest Research Institute.; Estados UnidosFil: Baratoux, David. Géosciences Environnement Toulouse; Francia. Centre National de la Recherche Scientifique; FranciaFil: Kaire, Maram. Ministry of Higher Education Research and Innovation; Senegal. Asociación Senegalesa para la Promoción de la Astronomía; SenegalFil: Leiva, Rodrigo. Southwest Research Institute.; Estados UnidosFil: Verbiscer, Anne J.. University of Virginia; Estados UnidosFil: Zangari, Amanda M.. Southwest Research Institute.; Estados UnidosFil: Colas, François. Centre National de la Recherche Scientifique. Observatoire de Paris; Francia. Sorbonne University; Francia. Centre National de la Recherche Scientifique; FranciaFil: Diop, Baidy Demba. Direction de la Formation et de la Communication; SenegalFil: Samaniego, Joseph I.. University of Colorado; Estados UnidosFil: Wasserman, Lawrence H.. Lowell Observatory; Estados UnidosFil: Benecchi, Susan D.. Planetary Science Institute; Estados UnidosFil: Caspi, Amir. Southwest Research Institute.; Estados UnidosFil: Gwyn, Stephen. Herzberg Astronomy and Astrophysics Research Centre; CanadáFil: Kavelaars, J. J.. Herzberg Astronomy and Astrophysics Research Centre; CanadáFil: Ocampo Uría, Adriana C.. National Aeronautics and Space Administration; Estados UnidosFil: Rabassa, Jorge Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Skrutskie, M. F.. University of Virginia; Estados UnidosFil: Soto, Alejandro. Southwest Research Institute.; Estados UnidosFil: Tanga, Paolo. Université Côte d’Azur; Francia. Centre National de la Recherche Scientifique; FranciaFil: Young, Eliot F.. Southwest Research Institute.; Estados UnidosFil: Stern, S. Alan. Southwest Research Institute.; Estados UnidosFil: Andersen, Bridget C.. University of Virginia; Estados UnidosFil: Arango Pérez, Mauricio E.. Universidad de Antioquia; ColombiaFil: Arredondo, Anicia. Massachusetts Institute of Technology; Estados UnidosFil: Artola, Rodolfo Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: García Migani, Esteban Andrés. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Geofísica y Astronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentin

Venus Evolution Through Time: Key Science Questions, Selected Mission Concepts and Future Investigations

In this work we discuss various selected mission concepts addressing Venus evolution through time. More specifically, we address investigations and payload instrument concepts supporting scientific goals and open questions presented in the companion articles of this volume. Also included are their related investigations (observations & modeling) and discussion of which measurements and future data products are needed to better constrain Venus’ atmosphere, climate, surface, interior and habitability evolution through time. A new fleet of Venus missions has been selected, and new mission concepts will continue to be considered for future selections. Missions under development include radar-equipped ESA-led EnVision M5 orbiter mission (European Space Agency 2021), NASA-JPL’s VERITAS orbiter mission (Smrekar et al. 2022a), NASA-GSFC’s DAVINCI entry probe/flyby mission (Garvin et al. 2022a). The data acquired with the VERITAS, DAVINCI, and EnVision from the end of this decade will fundamentally improve our understanding of the planet’s long term history, current activity and evolutionary path. We further describe future mission concepts and measurements beyond the current framework of selected missions, as well as the synergies between these mission concepts, ground-based and space-based observatories and facilities, laboratory measurements, and future algorithmic or modeling activities that pave the way for the development of a Venus program that extends into the 2040s (Wilson et al. 2022)

A taxonomic backbone for the global synthesis of species diversity in the angiosperm order Caryophyllales

The Caryophyllales constitute a major lineage of flowering plants with approximately 12500 species in 39 families. A taxonomic backbone at the genus level is provided that reflects the current state of knowledge and accepts 749 genera for the order. A detailed review of the literature of the past two decades shows that enormous progress has been made in understanding overall phylogenetic relationships in Caryophyllales. The process of re-circumscribing families in order to be monophyletic appears to be largely complete and has led to the recognition of eight new families (Anacampserotaceae, Kewaceae, Limeaceae, Lophiocarpaceae, Macarthuriaceae, Microteaceae, Montiaceae and Talinaceae), while the phylogenetic evaluation of generic concepts is still well underway. As a result of this, the number of genera has increased by more than ten percent in comparison to the last complete treatments in the Families and genera of vascular plants” series. A checklist with all currently accepted genus names in Caryophyllales, as well as nomenclatural references, type names and synonymy is presented. Notes indicate how extensively the respective genera have been studied in a phylogenetic context. The most diverse families at the generic level are Cactaceae and Aizoaceae, but 28 families comprise only one to six genera. This synopsis represents a first step towards the aim of creating a global synthesis of the species diversity in the angiosperm order Caryophyllales integrating the work of numerous specialists around the world

4to. Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad. Memoria académica

Este volumen acoge la memoria académica de la Cuarta edición del Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad, CITIS 2017, desarrollado entre el 29 de noviembre y el 1 de diciembre de 2017 y organizado por la Universidad Politécnica Salesiana (UPS) en su sede de Guayaquil. El Congreso ofreció un espacio para la presentación, difusión e intercambio de importantes investigaciones nacionales e internacionales ante la comunidad universitaria que se dio cita en el encuentro. El uso de herramientas tecnológicas para la gestión de los trabajos de investigación como la plataforma Open Conference Systems y la web de presentación del Congreso http://citis.blog.ups.edu.ec/, hicieron de CITIS 2017 un verdadero referente entre los congresos que se desarrollaron en el país. La preocupación de nuestra Universidad, de presentar espacios que ayuden a generar nuevos y mejores cambios en la dimensión humana y social de nuestro entorno, hace que se persiga en cada edición del evento la presentación de trabajos con calidad creciente en cuanto a su producción científica. Quienes estuvimos al frente de la organización, dejamos plasmado en estas memorias académicas el intenso y prolífico trabajo de los días de realización del Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad al alcance de todos y todas