57 research outputs found

    The mechanical properties of the Martian soil at the InSight landing site

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    The InSight mission is a NASA geophysical mission aimed at better understanding the structure of Mars and of the other rocky plan-ets of the solar system. To do so, various instruments are used, including a very sensitive seismometer (SEIS) and a dynamic self-penetrating heat probe (HP3) that have been placed on the Mars surface by the Instrument Deployment Arm (IDA). Besides geophys-ical data (which have definitely enriched and completed existing knowledge on the structure of Mars), the InSight instruments, togeth-er with orbiter observations and tests carried out on the soil with the IDA, have significantly increased the knowledge of the geologi-cal and geotechnical characteristics of the surface material at the InSight site, which is made up of a basaltic sand. In-situ data were also successfully compared with terrestrial previous estimates from terrestrial lab tests, carried out on various soil simulants. Small strain (elastic) parameters at small strains were derived from wave velocity measurements between the self-penetrating probe and the seismometer. Strength data were derived from both IDA operations and penetration data. The soil includes some pebbles within a somewhat cohesive sandy matrix, limiting the heat probe penetration to only 40 cm length. Thermal data were also obtained, allowing for some thermo-elastic modelling of the effect of the Phobos (one of the “Moons” of Mars) eclipses. Elastic data were also derived from the effects of wind on the ground, detected by SEIS

    Mapping Genetic Diversity of Cherimoya (Annona cherimola Mill.): Application of Spatial Analysis for Conservation and Use of Plant Genetic Resources

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    There is a growing call for inventories that evaluate geographic patterns in diversity of plant genetic resources maintained on farm and in species' natural populations in order to enhance their use and conservation. Such evaluations are relevant for useful tropical and subtropical tree species, as many of these species are still undomesticated, or in incipient stages of domestication and local populations can offer yet-unknown traits of high value to further domestication. For many outcrossing species, such as most trees, inbreeding depression can be an issue, and genetic diversity is important to sustain local production. Diversity is also crucial for species to adapt to environmental changes. This paper explores the possibilities of incorporating molecular marker data into Geographic Information Systems (GIS) to allow visualization and better understanding of spatial patterns of genetic diversity as a key input to optimize conservation and use of plant genetic resources, based on a case study of cherimoya (Annona cherimola Mill.), a Neotropical fruit tree species. We present spatial analyses to (1) improve the understanding of spatial distribution of genetic diversity of cherimoya natural stands and cultivated trees in Ecuador, Bolivia and Peru based on microsatellite molecular markers (SSRs); and (2) formulate optimal conservation strategies by revealing priority areas for in situ conservation, and identifying existing diversity gaps in ex situ collections. We found high levels of allelic richness, locally common alleles and expected heterozygosity in cherimoya's putative centre of origin, southern Ecuador and northern Peru, whereas levels of diversity in southern Peru and especially in Bolivia were significantly lower. The application of GIS on a large microsatellite dataset allows a more detailed prioritization of areas for in situ conservation and targeted collection across the Andean distribution range of cherimoya than previous studies could do, i.e. at province and department level in Ecuador and Peru, respectively

    Human diets drive range expansion of megafauna-dispersed fruit species

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    Significance Neotropical fruit species once dispersed by megafauna have regained relevance for diversifying human diets to address malnutrition. Little is known about the historic interactions between humans and these fruit species. We quantified the human role in modifying distribution ranges of Neotropical fruit species by comparing the distribution of fruit species that have been part of both human and megafauna diets with fruit species that were exclusively part of megafauna diets. Our results show that human food usage has expanded the distribution of species that would otherwise have suffered range contraction after extinction of megafauna. Our analyses help in identifying range segments of fruit species that may hold key genetic diversity to sustain food systems and to maintain critical ecosystem functions.</jats:p

    A Mesoamerican origin of cherimoya (Annona cherimola Mill.). Implications for the conservation of plant genetic resources

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    Knowledge on the structure and distribution of genetic diversity is a key aspect in order to plan and execute an efficient conservation and utilization of the genetic resources of any crop as well as for determining historical demographic inferences. In this work, a large data set of 1765 accessions of cherimoya (Annona cherimola Mill, Annonaceae), an underutilized fruit tree crop native to the neotropics and used as a food source by pre-Columbian cultures, was collected from 6 different countries across the American continent and amplified with 9 highly informative microsatellite markers. The structure analyses, fine representation of the genetic diversity and an ABC approach suggest a Mesoamerican origin of the crop, contrary to previous reports, with clear implications for the dispersion of plant germplasm between Central and South America in pre-Columbian times. These results together with the potential distribution of the species in a climatic change context using two different climate models provide new insights for the history and conservation of extant genetic resources of cherimoya that can be applied to other currently underutilized woody perennial crops.Peer Revie

    HipertensiĂłnportal en el embarazo: presentaciĂłnde un caso

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    The coexistence of pregnancy and liver disease represents a complex clinical situation. Pregnancy develops hypervolemic state due to increased splachnic blood flow, which contributes to increased portal pressure transmitted to collateral veins that increase the risk of variceal bleeding in these patients. We report the case of a 39 years old patient in the sixth pregnancy and without any previous medical history that presented pre-sinusoidal portal hypertension, and thanks to appropriate multidisciplinary management had an uncomplicated delivery. We review the literature relevant to the case

    HipertensiĂłnportal en el embarazo: presentaciĂłnde un caso

    No full text
    The coexistence of pregnancy and liver disease represents a complex clinical situation. Pregnancy develops hypervolemic state due to increased splachnic blood flow, which contributes to increased portal pressure transmitted to collateral veins that increase the risk of variceal bleeding in these patients. We report the case of a 39 years old patient in the sixth pregnancy and without any previous medical history that presented pre-sinusoidal portal hypertension, and thanks to appropriate multidisciplinary management had an uncomplicated delivery. We review the literature relevant to the case

    CaracterizaciĂłn de los pacientes con hemorragia de vĂ­as digestivas altas no varicosa en un hospital de tercer nivel de Cundinamarca, Colombia

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    Upper gastrointestinal tract bleeding is a common emergency whose most common etiology is a peptic ulcer. Restoration of intravascular volume and blood pressure management are priorities before identifying the cause of bleeding. After initial resuscitation and after hemodynamic stabilization has been achieved, an esophagogastroduodenoscopy (EGD) should be performed to identify the cause of bleeding and determine the treatment needed. This is a study performed at a third level referral hospital in Cundinamarca, Colombia. Materials and Methods: This is a retrospective study of data from electronic medical records of adult patients admitted to the emergency room of the Hospital Universitario de la Samaritana (HUS) because of upper gastrointestinal tract bleeding which ahd been diagnosed because of hematemesis, melena, rectal bleeding and/or anemia. Patients all underwent EGD between April 2010 and April 2011. Results: 385 patients with upper gastrointestinal tract bleeding were seen during the study period, but 100 were excluded because of bleeding secondary esophageal varices, incomplete clinical histories and lower gastrointestinal bleeding. A total of 285 patients were included. 69.1 % were older than 60 years, 73.3 % had hypertension, 55.1 % reported use of inflammatory drugs (NSAIDs) and aspirin (ASA), 19.6 % reported previous bleeding episodes, and 17.9 % had hemodynamic instability. 63 patients (22.1 %) required endoscopic hemostasis, and 32 (11.2 %) experienced rebleeding. Overall mortality reported was 13.1 % of which 55.3 % were men. Mortality attributable to gastrointestinal bleeding was 3.1 %. Conclusions: The majority of patients served by the HUS with upper GI bleeding are adults over 60 years. Peptic ulcers remain the most common diagnosis associated with the use of NSAIDs and ASA. The mortality rate is comparable to international standards. © 2013 Asociaciones Colombianas de Gastroenterología
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