Efecto genotóxico y citotóxico del plomo en meristemos radiculares de dos variedades de Vicia faba L. y su relación con la domesticación

Las problemáticas ambientales asociadas al incremento de metales pesados como el plomo han promovido la búsqueda de bioindicadores eficientes; Vicia faba es uno de los más utilizados, sin embargo, su aprovechamiento a nivel mundial ha provocado el uso indistinto de sus variedades silvestres y domesticadas, sin considerar las implicaciones del proceso de domesticación. Por tal motivo, la presente investigación tiene como objetivo evaluar el efecto genotóxico y citotóxico del plomo en células meristemáticas de raíz de semillas de V. faba  silvestre y de la variedad Major (domesticada) a través de la presencia de micronúcleos y la determinación del índice mitótico, con la finalidad de conocer sus respuestas ante este metal y su relación con la domesticación, así como sugerir el uso de la variedad más sensible como bioindicador. Para ello, los meristemos radiculares se sometieron a tratamientos con 0, 0.005, 0.01 y 0.02 g L-1 de acetato de plomo y se realizaron tinciones con aceto-orceína; se obtuvo la frecuencia de micronúcleos y el índice mitótico por cada 1000 células observadas. Los resultados obtenidos indican que el acetato de plomo tiene un efecto genotóxico y citotóxico diferencial entre ambas variedades, siendo V. faba var. Major la que presenta una alta sensibilidad al metal pesado, debido a una pérdida en la resistencia al estrés, por lo que se sugiere su uso como bioindicador; mientras que en las semillas silvestres mostraron mayor tolerancia al tener un bajo grado de domesticación

Magnetism of small V clusters embedded in a Cu fcc matrix: an ab initio study

We present extensive first principles density functional theory (DFT) calculations dedicated to analyze the magnetic and electronic properties of small V$_{n}$ clusters (n=1,2,3,4,5,6) embedded in a Cu fcc matrix. We consider different cluster structures such as: i) a single V impurity, ii) several V$_{2}$ dimers having different interatomic distance and varying local atomic environment, iii) V$_{3}$ and iv) V$_{4}$ clusters for which we assume compact as well as 2- and 1-dimensional atomic configurations and finally, in the case of the v) V$_{5}$ and vi) V$_{6}$ structures we consider a square pyramid and a square bipyramid together with linear arrays, respectively. In all cases, the V atoms are embedded as substitutional impurities in the Cu network. In general, and as in the free standing case, we have found that the V clusters tend to form compact atomic arrays within the cooper matrix. Our calculated non spin-polarized density of states at the V sites shows a complex peaked structure around the Fermi level that strongly changes as a function of both the interatomic distance and local atomic environment, a result that anticipates a non trivial magnetic behavior. In fact, our DFT calculations reveal, in each one of our clusters systems, the existence of different magnetic solutions (ferromagnetic, ferrimagnetic, and antiferromagnetic) with very small energy differences among them, a result that could lead to the existence of complex finite-temperature magnetic properties. Finally, we compare our results with recent experimental measurements.Comment: 7 pages and 4 figure

Estudio sobre Frecuencia de Diagnósticos Asociados a Mortalidad en el Hospital de Clínicas Año 2003

Introducción: El conocimiento de la tasa de mortalidaden un hospital es importante, más aún conocer losdiagnósticos médicos más frecuentemente asociados conla defunción. Esto obliga a dirigir esfuerzos terapéuticosy las políticas hospitalarias. Estas autoevaluaciones debenrealizarse periódicamente a causa de las condicionescambiantes del proceso salud - enfermedad.Objetivos:El propósito de este estudio fue determinar la frecuenciade los diagnósticos asociados con mortalidad hospitalariay las características demográficas de los pacientes quefallecieron en el Hospital de Clínicas en el año 2003.Material y métodos: Es estudio descriptivo, basadoen registros médicos de pacientes fallecidos en el Hospitalde Clínicas entre el 1 de enero al 31 de diciembredel año 2003. Las variables estudiadas fueron: edad,sexo, servicio hospitalario, tiempo de internación ydiagnósticos asociados a mortalidad, utilizando laclasificación CIE-10. Para el resumen de los datos seutilizó : mediana y rango.Resultados: La mortalidad hospitalaria fue de 5,8%(844 muertes/ 14.612 altas). De los que fallecieron, 641tenían datos completos para el estudio. El 52,5% eranvarones, con una mediana de 59 años. La mediana deestadía hospitalaria fue 3 días. El número de óbitos fuemayor en la Unidad de Cuidados Intensivos de Adultos,Pediatría y en la Primera Cátedra de Clínica Médica. Losdiagnósticos más frecuentemente asociados a mortalidadfueron las enfermedades Infecciosas y Cardiovasculares,seguidas por las Tumorales.Conclusiones: Se observó un aumento en la mortalidadhospitalaria. La mortalidad fue mayor en el sexomasculino y a mayor edad. La mediana de tiempo deinternación de los que fallecieron en el 2003 fue menor queen años anteriores (3 días). Hubo, además, un aumento dela frecuencia de enfermedades Infecciosas en comparacióncon las Cardiovasculares y Tumorales

Ampliaciones del rango de distribución de algunas especies de anfibios y reptiles en elsuroccidente de Ecuador

We present new localities of four species of amphibians and reptiles from foothill and high - Andean areas of the province of El Oro, southwestern Ecuador. These records significantly expand the global distributional ranges of Nymphargus buenaventura, Gastrotheca lateonata, Anolis lyra and Pliocercus euryzonus.Presentamos nuevas localidades para cuatro especies de anfibios y reptiles en áreas piemontanas y altoandinas en la provincia de El Oro, suroccidente de Ecuador. Estos registros expanden significativamente los rangos de distribución globales de Nymphargus buenaventura, Gastrotheca lateonata, Anolis lyra y Pliocercus euryzonus

Scalar-field Pressure in Induced Gravity with Higgs Potential and Dark Matter

A model of induced gravity with a Higgs potential is investigated in detail in view of the pressure components related to the scalar-field excitations. The physical consequences emerging as an artifact due to the presence of these pressure terms are analysed in terms of the constraints parting from energy density, solar-relativistic effects and galactic dynamics along with the dark matter halos.Comment: 26 pages, 3 figures, Minor revision, Published in JHE

Oral Anticoagulation and Risk of Symptomatic Hemorrhagic Transformation in Stroke Patients Treated With Mechanical Thrombectomy: Data From the Nordictus Registry

Introduction: We aimed to evaluate if prior oral anticoagulation (OAC) and its type determines a greater risk of symptomatic hemorrhagic transformation in patients with acute ischemic stroke (AIS) subjected to mechanical thrombectomy. Materials and Methods: Consecutive patients with AIS included in the prospective reperfusion registry NORDICTUS, a network of tertiary stroke centers in Northern Spain, from January 2017 to December 2019 were included. Prior use of oral anticoagulants, baseline variables, and international normalized ratio (INR) on admission were recorded. Symptomatic intracranial hemorrhage (sICH) was the primary outcome measure. Secondary outcome was the relation between INR and sICH, and we evaluated mortality and functional outcome at 3 months by modified Rankin scale. We compared patients with and without previous OAC and also considered the type of oral anticoagulants. Results: About 1.455 AIS patients were included, of whom 274 (19%) were on OAC, 193 (70%) on vitamin K antagonists (VKA), and 81 (30%) on direct oral anticoagulants (DOACs). Anticoagulated patients were older and had more comorbidities. Eighty-one (5.6%) developed sICH, which was more frequent in the VKA group, but not in DOAC group. OAC with VKA emerged as a predictor of sICH in a multivariate regression model (OR, 1.89 [95% CI, 1.01–3.51], p = 0.04) and was not related to INR level on admission. Prior VKA use was not associated with worse outcome in the multivariate regression model nor with mortality at 3 months. Conclusions: OAC with VKA, but not with DOACs, was an independent predictor of sICH after mechanical thrombectomy. This excess risk was associated neither with INR value by the time thrombectomy was performed, nor with a worse functional outcome or mortality at 3 months

Soil water content effects on net ecosystem CO2 exchange and actual evapotranspiration in a Mediterranean semiarid savanna of Central Chile

Biosphere-atmosphere water and carbon fluxes depend on ecosystem structure, and their magnitudes and seasonal behavior are driven by environmental and biological factors. We studied the seasonal behavior of net ecosystem CO2 exchange (NEE), Gross Primary Productivity (GPP), Ecosystem Respiration (RE), and actual evapotranspiration (ETa) obtained by eddy covariance measurements during two years in a Mediterranean Acacia savanna ecosystem (Acacia caven) in Central Chile. The annual carbon balance was −53 g C m−2 in 2011 and −111 g C m−2 in 2012, showing that the ecosystem acts as a net sink of CO2, notwithstanding water limitations on photosynthesis observed in this particularly dry period. Total annual ETa was of 128 mm in 2011 and 139 mm in 2012. Both NEE and ETa exhibited strong seasonality with peak values recorded in the winter season (July to September), as a result of ecosystem phenology, soil water content and rainfall occurrence. Consequently, the maximum carbon assimilation rate occurred in wintertime. Results show that soil water content is a major driver of GPP and RE, defining their seasonal patterns and the annual carbon assimilation capacity of the ecosystem, and also modulating the effect that solar radiation and air temperature have on NEE components at shorter time scales.This work was funded by FONDECYT projects 1120713 and 1170429, a grant from the Inter-American Institute for Global Change Research (IAI) [grant number CRN3056], which is supported by the US National Science Foundation [grant number GEO-1128040], and the Spanish Ministry of Economy and Competitiveness project GEI Spain (CGL2014-52838-C2-1-R), including ERDF founds. F. Bravo-Martínez is grateful to CONICYT for the grants “Formación de Capital Humano Avanzado-2009′′, “Beca de Apoyo al término de la tesis doctoral-2012′′, and CORFO INNOVA Grant N° 09CN14-5704. We thank to Enrique Pérez Sanchez-Cañete and Borja Ruíz- Reverter for technical support. We also thank “CODELCO–División Andina” for use of the site. C. Montes acknowledges the NASA Postdoctoral Program and to Universities Space Research Association

STREGA: STRucture and Evolution of the GAlaxy - I : Survey overview and first results

STREGA (STRucture and Evolution of the GAlaxy) is a guaranteed time survey being performed at the VST (the ESO Very Large Telescope Survey Telescope) to map about 150 square degrees in the Galactic halo, in order to constrain the mechanisms of galactic formation and evolution. The survey is built as a 5 yr project, organized in two parts: a core programme to explore the surrounding regions of selected stellar systems and a second complementary part to map the southern portion of the Fornax orbit and extend the observations of the core programme. The adopted stellar tracers are mainly variable stars (RR Lyraes and long-period variables) and main-sequence turn-off stars for which observations in the g, r, i bands are obtained. We present an overview of the survey and some preliminary results for three observing runs that have been completed. For the region centred on ω Cen (37 deg^2), covering about three tidal radii, we also discuss the detected stellar density radial profile and angular distribution, leading to the identification of extratidal cluster stars. We also conclude that the cluster tidal radius is about 1.2 deg, in agreement with values in the literature based on the Wilson model.Peer reviewedFinal Accepted Versio

Ultrahigh-energy neutrino follow-up of Gravitational Wave events GW150914 and GW151226 with the Pierre Auger Observatory

On September 14, 2015 the Advanced LIGO detectors observed their first gravitational-wave (GW) transient GW150914. This was followed by a second GW event observed on December 26, 2015. Both events were inferred to have arisen from the merger of black holes in binary systems. Such a system may emit neutrinos if there are magnetic fields and disk debris remaining from the formation of the two black holes. With the surface detector array of the Pierre Auger Observatory we can search for neutrinos with energy above 100 PeV from point-like sources across the sky with equatorial declination from about -65 deg. to +60 deg., and in particular from a fraction of the 90% confidence-level (CL) inferred positions in the sky of GW150914 and GW151226. A targeted search for highly-inclined extensive air showers, produced either by interactions of downward-going neutrinos of all flavors in the atmosphere or by the decays of tau leptons originating from tau-neutrino interactions in the Earth's crust (Earth-skimming neutrinos), yielded no candidates in the Auger data collected within $\pm 500$ s around or 1 day after the coordinated universal time (UTC) of GW150914 and GW151226, as well as in the same search periods relative to the UTC time of the GW candidate event LVT151012. From the non-observation we constrain the amount of energy radiated in ultrahigh-energy neutrinos from such remarkable events.Comment: Published version. Added journal reference and DOI. Added Report Numbe