1,856 research outputs found

    Precipitation variability and trends in Ghana: An intercomparison of observational and reanalysis products

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    Inter-annual variability and trends of annual/seasonal precipitation totals in Ghana are analyzed considering different gridded observational (gauge- and/or satellite-based) and reanalysis products. A quality-controlled dataset formed by fourteen gauges from the Ghana Meteorological Agency (GMet) is used as reference for the period 1961?2010. Firstly, a good agreement is found between GMet and all the observational products in terms of variability, with better results for the gauge-based products?correlations in the range of 0.7?1.0 and nearly null biases?than for the satellite-gauge merged and satellite-derived products. In contrast, reanalyses exhibit a very poor performance, with correlations below 0.4 and large biases in most of the cases. Secondly, a Mann-Kendall trend analysis is carried out. In most cases, GMet data reveal the existence of predominant decreasing (increasing) trends for the first (second) half of the period of study, 1961?1985 (1986?2010). Again, observational products are shown to reproduce well the observed trends?with worst results for purely satellite-derived data?whereas reanalyses lead in general to unrealistic stronger than observed trends, with contradictory results (opposite signs for different reanalyses) in some cases. Similar inconsistencies are also found when analyzing trends of extreme precipitation indicators. Therefore, this study provides a warning concerning the use of reanalysis data as pseudo-observations in Ghana.This study was supported by the EU project QWeCI (Quantifying Weather and Climate Impacts on health in developing countries), funded by the European Commission Seventh Framework Research Programme under the grant agreement 243964

    Alpha-tocopherol affects gene expression patterns of rabbit cumulus complexes and reduces apoptosis rate during in vitro maturation

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    Oxidative stress compromises oocyte developmental competence during in vitro maturation (IVM). Antioxidants such as vitamin E may avoid this imbalance. The aim of this study was to investigate the effect of a-Tocopherol (α-TocOH) on the relative mRNA abundance of genes involved in cumulus expansion (GJA1, PTGS2), cell cycle and viability (AKT1), cell cycle regulation and apoptosis (Tp53, CASP3) and antioxidant response (SOD2, GPX1, CAT) in rabbit cumulus oocyte complexes (COCs) in vitro matured. The apoptosis index in cumulus cells (CCs) and the hydrogen peroxide (H2O2) released by the COCs in maturation media were also assessed. For these purposes, COCs from follicles ≥1mm were recovered, selected and in vitro-matured for 16h (38ºC, 5% CO2) in a medium containing TCM-199 (Sigma, Madrid, Spain) with 0.3% bovine serum albumin (Sigma, Madrid, Spain) and 10 ng/mL Epidermal Growth Factor (EGF) (Sigma, Madrid, Spain) supplemented with 0, 100, 200 or 400 μM α- TocOH (Sigma, Madrid, Spain), named as 0E, 100E, 200E and 400E groups, respectivel

    The Possible White Dwarf-Neutron Star Connection

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    The current status of the problem of whether neutron stars can form, in close binary systems, by accretion-induced collapse (AIC) of white dwarfs is examined. We find that, in principle, both initially cold C+O white dwarfs in the high-mass tail of their mass distribution in binaries and O+Ne+Mg white dwarfs can produce neutron stars. Which fractions of neutron stars in different types of binaries (or descendants from binaries) might originate from this process remains uncertain.Comment: 6 pages. To appear in "White Dwarfs", ed. J. Isern, M. Hernanz, and E. Garcia-Berro (Dordrecht: Kluwer

    Nuclear fusion reactor materials: modelling atomic-scale irradiation damage in metal

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    Achieving nuclear fusion as an energy source on Earth is a practical goal that relies on continuing scientific and engineering innovation. Functional fusion reactors around the world today allow scientists and engineers to plan improvements that will eventually allow for greater energy output than the input required to operate the machine (including heating the plasma and operating the superconducting electromagnets that confine the plasma, among other energy inputs). The fusion reaction between nuclei of hydrogen isotopes is a carbon-free source of massive amounts of energy that could be paramount in a global turn towards greener energy. The fusion fuel needed to provide one person’s energy use for 100 years (assuming 20 kWh per day) is contained within roughly one and a half bathtubs of water and 3 laptop batteries. Given the enormous payoff of fusion, continued research and development are of great interest so that current challenges of heating and confining plasma, mitigating plasma disruptions, improving efficiency of magnets, and extending the lifetime of materials subjected to the harsh conditions surrounding the plasma may be overcome. Fusion reactor materials research carried out here at the BSC contributes to this ambitious goal. The idealistic goal for fusion materials research is to provide predictions about material behavior with the accuracy of quantum mechanical calculations at the scale of a full fusion reactor. Using strategic approximations and working at a small scale, computational fusion materials researchers can accurately reproduce and explain experimentally observed physical phenomena, such as the formation of microstructural defects in metals under neutron-irradiation, and offer the best predictions available for behavior of materials in future fusion reactor environments, where data about what will happen simply do not exist yet. In the study presented here, we examined the thermal conductivity, or how quickly a material allows heat to flow, of tungsten (W). W has been selected for plasma-facing components in ITER, which is currently under construction. We used LAMMPS atomic modelling of materials software and found that the thermal conductivity of W is significantly decreased in the presence of defects

    A Serosurvey of Selected Cystogenic Coccidia in Spanish Equids: First Detection of Anti-\u3cem\u3eBesnoitia\u3c/em\u3e spp. Specific Antibodies in Europe

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    Background: Equine besnoitiosis, caused by Besnoitia bennetti, and equine protozoal myeloencephalitis (EPM), caused by Sarcocystis neurona and Neospora hughesi are relevant equine diseases in the Americas that have been scarcely studied in Europe. Thus, a serosurvey of these cystogenic coccidia was carried out in Southern Spain. A cross-sectional study was performed and serum samples from horses (n = 553), donkeys (n = 85) and mules (n = 83) were included. An in-house enzyme-linked immunosorbent assay (ELISA) was employed to identify a Besnoitia spp. infection and positive results were confirmed by an a posteriori western blot. For Neospora spp. and Sarcocystis spp., infections were detected using in-house ELISAs based on the parasite surface antigens N. hughesi rNhSAG1 and S. neurona rSnSAG2/3/4. Risk factors associated with these protozoan infections were also investigated. Results: Antibodies against Besnoitia spp., Neospora spp. and Sarcocystis spp. infections were detected in 51 (7.1%), 46 (6.4%) and 20 (2.8%) of 721 equids, respectively. The principal risk factors associated with a higher seroprevalence of Besnoitia spp. were the host species (mule or donkey), the absence of shelter and the absence of a rodent control programme. The presence of rodents was the only risk factor for Neospora spp. infection. Conclusions: This study was the first extensive serosurvey of Besnoitia spp. infection in European equids accomplished by two complementary tests and gives evidence of the presence of specific antibodies in these populations. However, the origin of the infection is still unclear. Further parasite detection and molecular genotyping are needed to identify the causative Besnoitia and Neospora species. Finally, cross-reactions with antibodies directed against other species of Sarcocystis might explain the positive reactions against the S. neurona antigens

    A serosurvey of selected cystogenic coccidia in Spanish equids: first detection of anti-Besnoitia spp. specific antibodies in Europe

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    © The Author(s). 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.[EN]Background: Equine besnoitiosis, caused by Besnoitia bennetti, and equine protozoal myeloencephalitis (EPM), caused by Sarcocystis neurona and Neospora hughesi are relevant equine diseases in the Americas that have been scarcely studied in Europe. Thus, a serosurvey of these cystogenic coccidia was carried out in Southern Spain. A cross-sectional study was performed and serum samples from horses (n=553), donkeys (n=85) and mules (n=83) were included. An in-house enzyme-linked immunosorbent assay (ELISA) was employed to identify a Besnoitia spp. infection and positive results were confirmed by an a posteriori western blot. For Neospora spp. and Sarcocystis spp., infections were detected using in-house ELISAs based on the parasite surface antigens N. hughesi rNhSAG1 and S. neurona rSnSAG2/3/4. Risk factors associated with these protozoan infections were also investigated. Results: Antibodies against Besnoitia spp., Neospora spp. and Sarcocystis spp. infections were detected in 51 (7.1%), 46 (6.4%) and 20 (2.8%) of 721 equids, respectively. The principal risk factors associated with a higher seroprevalence of Besnoitia spp. were the host species (mule or donkey), the absence of shelter and the absence of a rodent control programme. The presence of rodents was the only risk factor for Neospora spp. infection. Conclusions: This study was the first extensive serosurvey of Besnoitia spp. infection in European equids accomplished by two complementary tests and gives evidence of the presence of specific antibodies in these populations. However, the origin of the infection is still unclear. Further parasite detection and molecular genotyping are needed to identify the causative Besnoitia and Neospora species. Finally, cross-reactions with antibodies directed against other species of Sarcocystis might explain the positive reactions against the S. neurona antigens.SIThis study was supported by several research projects (AGL 2010-20561, CYTED Thematic Network 113RT0469 Protozoovac and by PLATESA S20137ABI-2906). Daniel Gutiérrez Expósito has been financially supported by the Ministry of Science and Innovation (grant no. BES-2011-043753)

    Theoretical and experimental study of polarization switching in longwavelength VCSELs subject to parallel optical injection

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    We report a theoretical and experimental analysis of the polarization switching found in a single-transverse mode VCSEL when subject to parallel optical injection. We have found a novel situation in which injection locking of the parallel polarization and excitation of the free-running orthogonal polarization of the VCSEL are simultaneously obtained. Analytical expressions for the power of both linear polarizations in the previous steady state are determined. We show that considering two linear polarization modes in a model of a VCSEL subject to parallel optical injection leads to simpler expressions than those found for a VCSEL with only a single linear polarization. We show that the power emitted in both linear polarizations depend linearly on the injected power. The stability region of this solution is measured in the plane injected power versus frequency detuning.This work has been funded by the Ministerio de Economía y Competitividad, Spain under project TEC2015-65212-C3-1-P and cofinanced by FEDER funds

    Preparation of Kepler lightcurves for asteroseismic analyses

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    The Kepler mission is providing photometric data of exquisite quality for the asteroseismic study of different classes of pulsating stars. These analyses place particular demands on the pre-processing of the data, over a range of timescales from minutes to months. Here, we describe processing procedures developed by the Kepler Asteroseismic Science Consortium (KASC) to prepare light curves that are optimized for the asteroseismic study of solar-like oscillating stars in which outliers, jumps and drifts are corrected.Comment: Accepted for publication in MNRAS. 5 pages, 2 figure

    In vitro caloric restriction induces protective genes and functional rejuvenation in senescent SAMP8 astrocytes.

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    Astrocytes are key cells in brain aging, helping neurons to undertake healthy aging or otherwise letting them enter into a spiral of neurodegeneration. We aimed to characterize astrocytes cultured from senescence-accelerated prone 8 (SAMP8) mice, a mouse model of brain pathological aging, along with the effects of caloric restriction, the most effective rejuvenating treatment known so far. Analysis of the transcriptomic profiles of SAMP8 astrocytes cultured in control conditions and treated with caloric restriction serum was performed using mRNA microarrays. A decrease in mitochondrial and ribosome mRNA, which was restored by caloric restriction, confirmed the age-related profile of SAMP8 astrocytes and the benefits of caloric restriction. An amelioration of antioxidant and neurodegeneration-related pathways confirmed the brain benefits of caloric restriction. Studies of oxidative stress and mitochondrial function demonstrated a reduction of oxidative damage and partial improvement of mitochondria after caloric restriction. In summary, caloric restriction showed a significant tendency to normalize pathologically aged astrocytes through the activation of pathways that are protective against the age-related deterioration of brain physiology. © 2014 The AuthorsThis study was supported by grants SAF2009-13093, SAF2012-39852, and CSD2010-00045 from the Spanish MINECO, 2009/SGR/214 from the Generalitat of Catalonia, and the European Regional evelopment Fund (ERDF)Peer Reviewe

    Interaction of LATS1 with SMAC links the MST2/Hippo pathway with apoptosis in an IAP-dependent manner

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    Metastatic malignant melanoma is the deadliest skin cancer, and it is characterised by its high resistance to apoptosis. The main melanoma driving mutations are part of ERK pathway, with BRAF mutations being the most frequent ones, followed by NRAS, NF1 and MEK mutations. Increasing evidence shows that the MST2/Hippo pathway is also deregulated in melanoma. While mutations are rare, MST2/Hippo pathway core proteins expression levels are often dysregulated in melanoma. The expression of the tumour suppressor RASSF1A, a bona fide activator of the MST2 pathway, is silenced by promoter methylation in over half of melanomas and correlates with poor prognosis. Here, using mass spectrometry-based interaction proteomics we identified the Second Mitochondria-derived Activator of Caspases (SMAC) as a novel LATS1 interactor. We show that RASSF1A-dependent activation of the MST2 pathway promotes LATS1-SMAC interaction and negatively regulates the antiapoptotic signal mediated by the members of the IAP family. Moreover, proteomic experiments identified a common cluster of apoptotic regulators that bind to SMAC and LATS1. Mechanistic analysis shows that the LATS1-SMAC complex promotes XIAP ubiquitination and its subsequent degradation which ultimately results in apoptosis. Importantly, we show that the oncogenic BRAFV600E mutant prevents the proapoptotic signal mediated by the LATS1-SMAC complex while treatment of melanoma cell lines with BRAF inhibitors promotes the formation of this complex, indicating that inhibition of the LATS1-SMAC might be necessary for BRAFV600E-driven melanoma. Finally, we show that LATS1-SMAC interaction is regulated by the SMAC mimetic Birinapant, which requires C-IAP1 inhibition and the degradation of XIAP, suggesting that the MST2 pathway is part of the mechanism of action of Birinapant. Overall, the current work shows that SMAC-dependent apoptosis is regulated by the LATS1 tumour suppressor and supports the idea that LATS1 is a signalling hub that regulates the crosstalk between the MST2 pathway, the apoptotic network and the ERK pathway.Science Foundation IrelandUniversity College Dubli
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