3,465 research outputs found

    Isoscaling and the high Temperature limit

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    This study shows that isoscaling, usually studied in nuclear reactions, is a phenomenon common to all cases of fair sampling. Exact expressions for the yield ratio R21R_{21} and approximate expressions for the isoscaling parameters α\alpha and β\beta are obtained and compared to experimental results. It is concluded that nuclear isoscaling is bound to contain a component due to sampling and, thus, a words of caution is issued to those interested in extracting information about the nuclear equation of state from isoscaling.Comment: 7 pages, 1 figur

    Overexpression of the short endoglin isoform reduces renal fibrosis and inflammation after unilateral ureteral obstruction

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    33 p.-9 fig.-2 tab. Muñoz-Felix. J. M. et al.Transforming growth factor beta 1 (TGF-β1) is one of the most studied cytokines involved in renal tubulo¬interstitial fibrosis, which is characterized by myofibroblast abundance and proliferation, and high buildup of extracellular matrix in the tubular interstitium leading to organ failure. Endoglin (Eng) is a 180-kDa homodimeric transmembrane protein that regulates a great number of TGF-β1 actions in different biological processes, includ¬ing ECM synthesis. High levels of Eng have been observed in experimental models of renal fibrosis or in biopsies from patients with chronic kidney disease. In humans and mice, two Eng isoforms are generated by alternative splicing, L-Eng and S-Eng that differ in the length and composition of their cytoplasmic domains. We have previously described that L-Eng overexpression promotes renal fibrosis after unilateral ureteral obstruction (UUO). However, the role of S-Eng in renal fibrosis is unknown and its study would let us analyze the possible function of the cytoplasmic domain of Eng in this process. For this purpose, we have generated a mice strain that overexpresses S-Eng (S-ENG+) and we have performed an UUO in S-ENG+ and their wild type (WT) control mice. Our results indicate that obstructed kidney of S-ENG+ mice shows lower levels of tubulo-interstitial fibrosis, less inflammation and less interstitial cell proliferation than WT littermates. Moreover, S-ENG+ mice show less activation of Smad1 and Smad2/3 pathways. Thus, S-Eng overexpression reduces UUO-induced renal fibrosis and some associated mechanisms. As L-Eng overexpression provokes renal fibrosis we conclude that Eng-mediated induction of renal fibrosis in this model is dependent on its cytoplasmic domain.This study has been supported by grants from Ministerio de Economía y Competitividad of Spain (SAF2013-43421-R to CB; and SAF2013-45784-R to JML-N), Junta de Castilla y León (GR100, JML-N), Institute Queen Sophie for Renal Research, Fundación Renal Íñigo Álvarez de Toledo, Madrid, Spain (0016¬002), Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER, CB) (ISCIII-CB06/07/0038) and Red de Investigación Cooperativa en Enfermedades Renales (REDINREN, JML-N) (R12/0021/ 0032). CIBERER and REDINREN are initiatives of the Instituto de Salud Carlos III (ISCIII) of Spain supported by FEDER funds. BO and ENG are supported by fellowships from Ministerio de Economía y Competitividad (BES-2011-048968 and BES-2008-005550). JMMF, LPR and CC are supported by fellowships from Junta de Castilla y León and Fondo Social Europeo (EDU/1204/2010 and EDU/1083/2013).Peer reviewe

    Spontaneous Symmetry Breakdown in non-relativistic Quantum Mechanics

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    The advantages and disadvantages of some pedagogical non-relativistic quantum-mechanical models, used to illustrate spontaneous symmetry breakdown, are discussed. A simple quantum-mechanical toy model (a spinor on the line, subject to a magnetostatic interaction) is presented, that exhibits the spontaneous breakdown of an internal symmetry.Comment: 19 pages, 5 figures. arXiv admin note: substantial text overlap with arXiv:1111.1213. Equations (30) and (31) have been corrected. Other minor correction

    Updating known distribution models for forecasting climate change impact on endangered species

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    To plan endangered species conservation and to design adequate management programmes, it is necessary to predict their distributional response to climate change, especially under the current situation of rapid change. However, these predictions are customarily done by relating de novo the distribution of the species with climatic conditions with no regard of previously available knowledge about the factors affecting the species distribution. We propose to take advantage of known species distribution models, but proceeding to update them with the variables yielded by climatic models before projecting them to the future. To exemplify our proposal, the availability of suitable habitat across Spain for the endangered Bonelli’s Eagle (Aquila fasciata) was modelled by updating a pre-existing model based on current climate and topography to a combination of different general circulation models and Special Report on Emissions Scenarios. Our results suggested that the main threat for this endangered species would not be climate change, since all forecasting models show that its distribution will be maintained and increased in mainland Spain for all the XXI century. We remark on the importance of linking conservation biology with distribution modelling by updating existing models, frequently available for endangered species, considering all the known factors conditioning the species’ distribution, instead of building new models that are based on climate change variables only.Ministerio de Ciencia e Innovación and FEDER (project CGL2009-11316/BOS

    Conceptual design of the ITER fast-ion loss detector

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    et al.A conceptual design of a reciprocating fast-ion loss detector for ITER has been developed and is presented here. Fast-ion orbit simulations in a 3D magnetic equilibrium and up-to-date first wall have been carried out to revise the measurement requirements for the lost alpha monitor in ITER. In agreement with recent observations, the simulations presented here suggest that a pitch-angle resolution of ∼5° might be necessary to identify the loss mechanisms. Synthetic measurements including realistic lost alpha-particle as well as neutron and gamma fluxes predict scintillator signal-to-noise levels measurable with standard light acquisition systems with the detector aperture at ∼11 cm outside of the diagnostic first wall. At measurement position, heat load on detector head is comparable to that in present devices.This research was supported in part by the Spanish Ministry of Economy and Competitiveness (Grant Nos. RYC2011-09152, FIS2015-69362-P, and ENE2012- 31087) and the Marie Curie FP7 Integration Grant (No. PCIG11-GA2012-321455).Peer Reviewe
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