1,137 research outputs found

    Dependence of exchange anisotropy and coercivity on the Fe–oxide structure in oxygen-passivated Fe nanoparticles

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    Ultrafine Fe particles have been prepared by the inert gas condensation method and subsequently oxygen passivated. The as-obtained particles consist in an Fe core surrounded by an amorphous Fe-oxide surface layer. The antiferromagnetic character of the Fe-oxide surface induces an exchange anisotropy in the ferromagnetic Fe core when the system is field cooled. Samples have been heat treated in vacuum at different temperatures. Structural changes of the Fe–O layer have been monitored by x-ray diffraction and transmission electron microscopy. Magnetic properties as coercivity, hysteresis loop shift, and evolution of magnetization with temperature have been analyzed for different oxide crystallization stages. A decrease of the exchange anisotropy strength is reported as the structural disorder of the surface oxide layer is decreased with thermal treatment

    Dependence of exchange anisotropy and coercivity on the Fe–oxide structure in oxygen-passivated Fe nanoparticles

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    Ultrafine Fe particles have been prepared by the inert gas condensation method and subsequently oxygen passivated. The as-obtained particles consist in an Fe core surrounded by an amorphous Fe-oxide surface layer. The antiferromagnetic character of the Fe-oxide surface induces an exchange anisotropy in the ferromagnetic Fe core when the system is field cooled. Samples have been heat treated in vacuum at different temperatures. Structural changes of the Fe–O layer have been monitored by x-ray diffraction and transmission electron microscopy. Magnetic properties as coercivity, hysteresis loop shift, and evolution of magnetization with temperature have been analyzed for different oxide crystallization stages. A decrease of the exchange anisotropy strength is reported as the structural disorder of the surface oxide layer is decreased with thermal treatment

    Concentraciones totales de Fe, Mn, Al y P en Alfisoles, Oxisoles y Ultisoles en Misiones, Argentina

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    Uno de los principales problemas en la producción agrícola en la Provincia de Misiones (Argentina) es la baja disponibilidad de fósforo (P) en Alfisoles, Oxisoles y Ultisoles, aunque se detectan altas concentraciones de P total. El objetivo del trabajo fue determinar la distribución de las concentraciones totales de Fe, Mn, Al y P en Alfisoles, Oxisoles y Ultisoles. Kandiudalfes Ródico y Mólico, Eutrudox Ródico, Hapludox Húmico, Kandihumultes Típicos. Se determinaron pH en agua relación 1:2,5; carbono orgánico (CO) por Walkley-Black; textura por Bouyouccos; Fósforo total (Pt) por digestión con H2 SO4 – H2 O2 – HF. El fraccionamiento de Fe, Mn, y Al se realizó siguiendo el procedimiento propuesto por Shuman y modificado por McDaniel y Buol adaptado para el fraccionamiento de elementos. Las concentraciones de Fe, Mn y Al fueron determinadas por espectrofotometría de absorción atómica. Se concluye que: i) las formas amorfas o pobremente cristalinas de Fe, fueron las formas más importantes hallada de este elemento; ii) las principales formas de Mn halladas fueron los óxidos cristalinos de Mn o formas coprecipitadas, encontrándose que las concentraciones totales de Mn disminuyeron en profundidad y están estrechamente relacionadas a los contenidos de arcillas del suelo; iii) para Al se detectaron las formas amorfas y las cristalinas de óxido de hierro o formas coprecipitadas; iv) en los tres órdenes de suelos la tercera fracción en orden de importancia fue el Al asociadas a la materia orgánica; v) la menor concentración de fósforo fue hallada en los Alfisoles y la mayor en los Ultisoles y su disponibilidad es afectada principalmente por la presencia de diferentes formas de Fe, Mn, y Al

    Genetics applied to clinical practice in neurodevelopmental disorders

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    Las evidencias genéticas de los trastornos del neurodesarrollo están ampliamente sustentadas en la literatura médica. Los avances en la genética y la tecnología han incrementado la rentabilidad diagnóstica de los estudios actuales de un 3-5% a un 30-40% en los pacientes con discapacidad intelectual o trastornos del espectro autista. En este sentido, los estudios por microarrays cromosómicos muestran un mayor poder diagnóstico que las técnicas convencionales (cariotipo, análisis de subtelómeros…). Los protocolos más recientes en el apartado biomédico del estudio genético de estos trastornos sitúan los microarrays cromosómicos como análisis de primera línea, recomendando otros estudios específicos según las características clínicas del paciente (síndrome X frágil, mutación en PTEN...). En la evaluación de otros trastornos del neurodesarrollo (trastorno por déficit de atención/hiperactividad, trastornos del aprendizaje...), la realización de pruebas genéticas está limitada y condicionada a las características clínicas o antecedentes familiares o personales del paciente; incluso en estas situaciones, no existen protocolos de evaluación o derivación genéticaThe medical literature contains a wide body of evidence supporting genetic involvement in neurodevelopmental disorders. Advances made in genetics and technology have increased the diagnostic cost-effectiveness of current studies from 3-5% to 30-40% in patients with intellectual disability or autism spectrum disorders. In this regard, chromosomal microarray studies display greater diagnostic power than conventional techniques (karyotype, subtelomeric analyses, etc.). The latest protocols in the biomedical field of the genetic study of these disorders cite chromosomal microarrays as the first-line analysis, while also recommending other specific studies depending on the patient’s clinical features (fragile X syndrome, PTEN mutation, etc.). In the evaluation of other neurodevelopmental disorders (attention deficit hyperactivity disorder, learning disorders, etc.), the number of genetic tests carried out is limited and conditioned by the clinical characteristics or the patient’s familial or personal history. Even in these situations, there are no genetic referral or evaluation protocol

    頭部外傷の治療(交通事故による脳障害,第48回千葉医学会学術大会,第17回千葉県医師会学術大会,第10回日医医学講座,連合大会)

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    BACKGROUND:The negative consequences of energy dense foods are well known, yet people increasingly make unhealthy food choices leading to obesity (i.e., risky decisions). The aims of this study were: [1] to compare performance in decision-making tasks under risk and under ambiguity between individuals with obesity, overweight and normal weight; [2] to examine the associations between body mass index (BMI) and decision-making, and the degree to which these associations are modulated by reward sensitivity. METHODS:Seventy-nine adults were recruited and classified in three groups according to their BMI: obesity, overweight and normal-weight. Groups were similar in terms of age, education and socio-economic status, and were screened for comorbid medical and mental health conditions. Decision-making under risk was measured via the Wheel of Fortune Task (WoFT) and decision-making under ambiguity via the Iowa Gambling Task (IGT). Reward sensitivity was indicated by the Sensitivity to Punishment and Sensitivity to Reward Questionnaire (SPSRQ). RESULTS:Individuals with obesity made riskier choices in the WoFT, specifically in choices with an expected value close to zero and in the propensity to risk index. No differences were found in IGT performance or SPSRQ scores. BMI was associated with risk-taking (WoFT performance), independently of reward sensitivity. CONCLUSIONS:Obesity is linked to a propensity to make risky decisions in experimental conditions analogous to everyday food choices

    Emerging Cooperation in N-Person Iterated Prisoner's Dilemma over Dynamic Complex Networks

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    The N-Person Iterated Prisoner's Dilemma (NIPD) is an interesting game that has proved to be very useful to explore the emergence of cooperation in multi-player scenarios. Within this game, the way that agents are interconnected is a key element that influences cooperation. In this context, complex networks provide a realistic model of the topological features found in Nature and in many social and technological networks. Considering these networks, it is interesting to study the network evolution, given the possibility that agents can change their neighbors (dynamic rewire), when non-cooperative behaviors are detected. In this paper, we present a model of the NIPD game where a population of genetically-coded agents compete altogether. We analyze how different game parameters, and the network topology, affect the emergence of cooperation in static complex networks. Based on that, we present the main contribution of the paper that concerns the influence of dynamic rewiring in the emergence of cooperation over the NIPD

    Implementation of multi-layer techniques using FEDERICA, PASITO and OneLab network infrastructures

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    Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. V. López, J. L. Añamuro, V. Moreno, J. E. L. De Vergara, J. Aracil, C. García, J. P. Fernández-Palacios, and M. Izal, "Implementation of multi-layer techniques using FEDERICA, PASITO and OneLab network infrastructures", in 17th IEEE International Conference on Networks, ICON 2011, p. 89-94This paper describes an implementation of multilayer techniques using the network infrastructure provided by FEDERICA, PASITO and OneLab projects. FEDERICA project provides a network infrastructure, based on virtualization capabilities in both network and computing resources, which creates custom-made virtual environments. PASITO is a layer- 2 network that connects universities and research centers in Spain. OneLab measurements tools allow carrying out highaccuracy active network measurements. Thanks to FEDERICA and PASITO, we have a multi-layer architecture where the traffic is routed based on the measurements of OneLab equipment. To carry out this experiment, we have developed a Multi-layer Traffic Engineering manager and an implementation of the Path Computation Element Protocol to solve the lack of a control plane in IP oriented networks. This work shows the feasibility of multilayer techniques as a convenient solution for network operators and it validates our Path Computation Element implementation.This work has been partially funded by the Spanish Ministry of Education and Science under project ANFORA (TEC2009-13385), by the Spanish Ministry of Industry, Tourism and Trade under PASITO project, and by the European Union under project OneLab2 (FP7-224263). Authors would like to thank Mauro Campanella (GARR, the project coordinator of FEDERICA) and Miguel Angel Sotos (RedIris) for their support to carry out this work

    Light-activated electroforming in ITO/ZnO/p-Si resistive switching devices

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    We report on light-activated electroforming of ZnO/p-Si heterojunction memristors with transparent indium tin oxide as the top electrode. Light-generated electron-hole pairs in the p-type substrate are separated by the external electric field and electrons are injected into the active ZnO layer. The additional application of voltage pulses allows achieving different resistance states that end up in the realization of the low resistance state (LRS). This process requires much less voltage compared to dark conditions, thus avoiding undesired current overshoots and achieving a self-compliant device. The transport mechanisms governing each resistance state are studied and discussed. An evolution from an electrode-limited to a space charge-limited transport is observed along the electroforming process before reaching the LRS, which is ascribed to the progressive formation of conductive paths that consequently induce the growth of conductive nanofilaments through the ZnO layer. This work was financially supported by the Spanish Ministry of Economy and Competitiveness (Project Nos. TEC2012-38540-C02-01 and TEC2016-76849-C2-1-R). O.B. also acknowledges the subprogram "Ayudas para Contratos Predoctorales para la Formación de-Doctores" from the Spanish Ministry of Economy and Competitiveness for economical support. J.L.F. acknowledges the subprogram "Ayudas para la Formación de Profesorado Universitario" (No. FPU16/06257) from the Spanish Ministry of Education, Culture and Sports for economical support. X.P., C.L., and C.G. are grateful to C. Frilay for his expertise in the maintenance of the sputtering setup used for the growth of the ZnO films

    Changes in the number of circulating TCM and TEM subsets in renal transplantation: relationship with acute rejection and induction therapy

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    Effector (TEM) and central memory (TCM) T cells have been recently described as the main memory T-cell subsets generated after primary immune response, with a potential role in graft rejection after rechallenge with alloantigen. Because of their effector function, they could be involved in driving the response against the allograft, leading to rejection. In this study, we sought to investigate the different memory T-cell subpopulations in peripheral blood from a cohort of 90 patients who underwent consecutive renal transplant, and their association with acute rejection (AR) episodes and induction therapy. Twenty-one of them were monitored in the short term during the first 2 months after transplantation. Three of them suffered an AR but no changes in the circulating levels of either CD4+ or CD8+ TEM were observed as compared with rejection-free renal transplant patients. In total, 69 patients out of 90 were monitored in the long term. Even 2 years after transplantation, maintained increased numbers of peripheral blood CD4+ TEM were observed in patients suffering with AR. Interestingly, induction therapy with thymoglobulin, but not with basiliximab, produced an increase in circulating CD4+ TEM cells at 6 months after transplantation. In conclusion, our data suggest that AR episodes favor the induction of TEM cells in the periphery of renal transplant patients in the long term. It remains to be determined whether such an effect has any impact on long-term renal transplantation
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