666 research outputs found

    Optimal conclusive teleportation of quantum states

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    Quantum teleportation of qudits is revisited. In particular, we analyze the case where the quantum channel corresponds to a non-maximally entangled state and show that the success of the protocol is directly related to the problem of distinguishing non-orthogonal quantum states. The teleportation channel can be seen as a coherent superposition of two channels, one of them being a maximally entangled state thus, leading to perfect teleportation and the other, corresponding to a non-maximally entangled state living in a subspace of the d-dimensional Hilbert space. The second channel leads to a teleported state with reduced fidelity. We calculate the average fidelity of the process and show its optimality.Comment: 8 pages, revtex, no figure

    Un lugar entre la tierra y las estrellas. Luces y sombras en la Torre Einstein

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    La torre Einstein se erige en 1921 en el Telegraphsberg de Potsdam con un único objetivo: la demostración empírica (o refutación) de las bases de la Teoría de la Relatividad enunciada por Albert Einstein. Establecida ya desde su origen como un monumento, que el tiempo ha consolidado como icono de una incipiente vanguardia, la Torre Einstein es, a su vez, la historia de un triple fracaso. El presente artículo describe este primer proyecto de Erich Mendelsohn, no tanto como la apertura de una carrera profesional, sino como el necesario cierre de la vía iniciada con sus anteriores dibujos de guerra

    Skeletal muscle mTORC1 regulates whole-body metabolism

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    Skeletal muscle, which represents over 40% of the total body mass, is a dynamic tissue with a key role in the maintenance of metabolic homeostasis. Several lines of evidence indicate that alterations of the normal muscle function, as for example in muscular dystrophies, obesity or diabetes, can affect the metabolism at the whole-body level (DeFronzo & Tripathy, 2009; Llagostera et al, 2007). We focused on the mTORC1 signaling pathway in skeletal muscle, responsible for the transduction of insulin signaling and nutrient sensing from the cell surface to the increased protein synthesis and anabolic processes that allow cells to grow and proliferate (Laplante & Sabatini, 2012). We decided to characterize the metabolic phenotype of young and old RAmKO (Raptor muscle knock-out) and TSCmKO (TSC1 muscle knock-out) mice, where mTORC1 activity in skeletal muscle is inhibited or constitutively activated respectively. Young RAmKO mice were lean and dystrophic, insulin resistant, with increased energy expenditure and resistant to a HFD. This correlated with an increase in histone deacetylases (HDACs) and a down-regulation of genes involved in glucose and fatty acid metabolism. Young TSCmKO mice were lean, glucose intolerant with a decrease in Akt signaling pathway, resistant to a HFD and showed reduced accumulation of glycogen and lipids in the liver. Both mouse models developed a myopathy with age, with decreased fat and lean mass, and both RAmKO and TSCmKO mice developed metabolic acidosis with insulin resistance and increased intramyocelular lipid content. While the effects of mTORC1 inhibition in skeletal muscle of young mice were limited to muscle, its sustained activation caused changes not only in skeletal muscle but also at the whole-body level. TSCmKO mice were lean, with increased insulin sensitivity and fatty acid oxidation, and showed changes in other metabolic organs. This indicated the possible influence of a muscle secreted myokine. Secretion of fibroblast growth factor 21 (FGF21) by skeletal muscle has been shown to protect from diet-induced obesity and insulin resistance (Kim et al, 2013c). We showed that most of the metabolic phenotype of TSCmKO mice was due to increased plasma concentrations of FGF21, a hormone that stimulates glucose uptake and fatty acid oxidation. FGF21 was released from skeletal muscle mainly because of mTORC1-triggered ER stress and activation of the PERK-eIF2α-ATF4 pathway. Treatment of TSCmKO mice with a chemical chaperone, which alleviates ER stress, reduced FGF21 production in muscle and increased body weight. Moreover, injection of function-blocking antibodies directed against FGF21 largely normalized the metabolic phenotype of the mice. We further confirmed the involvement of muscle FGF21 in the development of the TSCmKO mice phenotype by genetic knock-out of FGF21 specifically in skeletal muscle. DKO mice (muscle TSC1/FGF21 KO) showed normalized plasma glucose and ketone body levels, as well as an increase in body weight, growth and lean mass. This was a direct consequence of muscle secreted FGF21, as plasma FGF21 levels were normalized in DKO mice. Surprisingly, fat mass was still reduced in these mice. We observed increased expression of fatty acid oxidation markers in the muscle of DKO and a decrease in the lipid content, which could contribute to the ongoing wasting of the adipose tissue. Nevertheless, this could indicate either a compensatory mechanism that did not allow DKO mice to gain fat mass, or a FGF21-independent mechanism causing the increased lipolysis of white adipose tissue. Interestingly, when we knocked-out FGF21 specifically in skeletal muscle in a non-genetically altered mouse, we observed the development of obesity induced diabetes, as these mice became heavier, with increased fat mass, higher plasma glucose levels and glucose intolerance. In conclusion, we have confirmed that alterations to mTORC1 signaling pathway in skeletal muscle directly affect whole body metabolism, which highlights the importance of this tissue in maintaining energy stability. Moreover, we show that proper balance in mTORC1 signaling is essential for muscle tissue integrity and metabolic homeostasis, since both long-term activation and inhibition originated a myopathy that mimicked the main metabolic complications of dystrophic patients. Furthermore, activation of mTORC1 in skeletal muscle, through induction of ER stress, increased the secretion of FGF21 into the circulation, which caused progressive metabolic adaptations to compensate for the altered muscle dynamics. Thus, muscle mTORC1 could serve as a potential target to treat metabolic complications of diseases like diabetes, obesity and muscle dystrophies

    Euskaraz auzitaratzeko eskubidea

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    A continuación se analiza la normativa vigente en materia lingüística respecto a la Administración de Justicia, y, en especial, la valoración que se le otorga al conocimiento del euskara a la hora de evaluar a los aspirantes a la judicatura.Jarraian, Justizia Administraziorako indarrean dagoen araudiak hizkuntzaren inguruan zer-nolako konponbideak eskaintzen dituen aztertuko da, eta bereziki euskararen ezagutzak zer balioespen daukan.Nous étudions ensuite les normes en vigueur en matière linguistique en ce qui concerne l'Administration de Justice et, spécialement, la valeur que l'on prête à la connaissance du basque au moment d'évaluer les aspirants à la magistrature.The laws, rules and regulations currently in force which regulate linguistic matters with respect to the Administration of Justice, and, especially, the value attributed to the knowledge of Basque when evaluating candidates to the judicature

    Principio de disponibilidad y protección de datos personales : a la búsqueda del necesario equilibrio en el espacio judicial penal europeo

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    Se ha achacado con relativa frecuencia que la cooperación judicial penal en la UE, o el progresivo desarrollo del espacio judicial penal europeo, se ha centrado fundamentalmente en términos de efi cacia en la persecución de infracciones penales, aparcando en un segundo plano la protección de los derechos y las garantías que pue- den verse afectados. Aunque existieran precedentes sobre la cuestión, es en el Consejo Europeo de Tampere cuando se proclama que el principio del reconocimiento mutuo de las resoluciones judiciales será la “piedra angular” de la cooperación judicial en la UE 1 . La primera concreción de este principio en el ámbito penal será la adopción de la Decisión Marco (DM) sobre la orden europea de detención y entrega, de 13 de junio de 2002

    Professor - pesquisador de sua prática : dificuldades e motivações

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    Neste trabalho analisamos três casos de professores de ciências que pesquisaram sua prática docente. Focalizamos os processos de elaboração de suas pesquisas, que resultaram na descoberta de falhas e acertos na condução docente e numa correspondente mudança subjetiva em relação à atividade de ensinar ciências. Os dados empíricos deste trabalho são constituídos pelos diários de pesquisa, memoriais de qualificação e pelas dissertações destes professores, além das entrevistas e conversas informais com os mesmos. Destacamos a insatisfação inicial em relação a sua prática docente, a elaboração do diário de bordo, ocasião de reflexão inicial sobre sua prática e também registro fundamental de pesquisa, a adoção de referenciais para elaborar e analisar os dados e o auxílio de um grupo de interlocutores na academia, formado por colegas e orientadores

    Propuesta de mejora de la calidad del efluente pluvial en la cuenca La Perla, de la ciudad de Mar del Plata.

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    El objetivo general del presente trabajo es proponer un tratamiento a los efluentes pluviales que desembocan en las playas de la zona norte de la ciudad de Mar del Plata para mejorar el estado sanitario de estas playas

    Guías clínicas para la cirugía de la epilepsia y de los trastornos del movimiento

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    The guidelines for the surgical treatment of the movement disorders and epilepsy have been performed by the functional and stereotactic group of the Spanish Society of Neurosugery (SENEC). The guidelines are recomendations in terms of indication for surgery including timing and methods. The format are supported by prospective studies based in scientific evidence and the expert opinion of the group

    El quehacer científico versus el quehacer áulico : buscando rasgos del quehacer científico en libros de texto

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    Here we outline a search for features of the scientific tasks in the paper-and-pencil and experimental activities proposed in the textbooks mostly used in Tandil. The topics selected were electric current, direct current circuits and electrical current effects. Among other results, it is worth nothing the notable variability found concerning the link between model and reality. There are also some reflections on the lack of emphasis in the conceptual analysis, on the possibility of diversifying the ways for the solution and the discussion on the relevance of mathematical expressions and numerical values

    Los gasómetros de Zollverein. Historia de una recuperación singular

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    Por su rotundidad formal y gran volumen, los mal llamados gasómetros (no son medidores sino depósitos de gas) han devenido fácilmente en iconos o hitos asociados a la memoria del lugar defendidos por asociaciones ciudadanas y particulares. Tras una breve introducción analizando la situación actual y sus problemas de mantenimiento y pervivencia, en este trabajo se realiza un recorrido por su evolución y desarrollo histórico. Ello lleva a plantear la cuestión de la estrategias de conservación, considerándose imprescindible el estudio caso a caso, atendiendo a su estado, situación y relación con las comunidades de su entorno. Como ejemplo, el área de Zollverein en la cuenca del Ruhr ofrece un interesante conjunto de elementos sobrevivientes y recuperados que muestran diversas soluciones llevadas a la práctica
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