12,768 research outputs found

    Bousfield localization on formal schemes

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    Let (X, O_X) be a noetherian formal scheme and consider D_qct(X) its derived category of sheaves with quasi-coherent torsion homology. We show that there is a bijection between the set of rigid (i.e. \tensor-ideals) localizing subcategories of D_qct(X) and subsets in X, generalizing previous work by Neeman. If moreover X is separated, the associated localization and acyclization functors are described in certain cases. When Z is a stable for specialization subset of X, its associated acyclization is \Gamma_Z. When X is an scheme, the corresponding localizing subcategories are generated by perfect complexes and we recover Thomason's classification of thick subcategories. On the other hand, if Y is a generically stable subset of X, we give an expression for the associated localization functor.Comment: Relaxed the separation hypothesis. Added connection with Thomason's classification of thick subcategorie

    Análisis de algunas teorías de la formación aplicadas al concepto de generatividad

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    We found exciting to study how generativity has evolved since Erikson (1950) outside the Psychology and Sociology disciplines, and had permeated into the fields of Ecology, Grammar and Syntax, and Information and Communication Technology (ICT), without losing part of the essence of the genuine meaning given by Erikson back then, about the generative task and generativity as a construct. I wanted to investigate this further, and my findings turned out to be very interesting. In this paper I perform a basic analysis of some training theories applied to the generativity concept as a task and a construct since Erikson (1950), in the field of Psychology and Sociology, Grammar and Syntax, Ecology, Information and Communication Technology (ICT).Nos pareció apasionante estudiar cómo la generatividad había evolucionado desde Erikson (1950) fuera de las disciplinas de la Psicología y la Sociología, y había calado en los campos de la Ecología, la Gramática y la Sintaxis, y las Tecnologías de la Información y la Comunicación (TIC), sin perder parte de la esencia del sentido genuino que Erikson le dio entonces, sobre la tarea generativa y la generatividad como constructo. Quise investigar más sobre esto, y mis hallazgos resultaron ser muy interesantes En este trabajo realizo un análisis básico de algunas teorías de la formación aplicadas al concepto de generatividad como tarea y como constructo desde Erikson (1950), en el ámbito de la Psicología y la Sociología, la Gramática y la Sintaxis, la Ecología y las Tecnologías de la Información y la Comunicación (TIC)

    Advanced architectural descriptors in foams: novel 3D computational methods

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    This work presents 3D computational strategies aimed at providing foam de-structuration of the basic components of a cellular material (struts and cell walls) offering the possibility of analysing separately the structural elements that play an important role in the physical properties of thee materials. Two different methodologies have been used depending on the topological similarities existing between the struts and cell walls: 3D erosion-dilation procedure (thick struts) and solid classification algorithm (thin struts). In a second step, analysis of cell walls is performed in order to show the advantages of analysing separately the two foams components. Particularly, cell wall thickness distribution reveals differences that could not be found prior to the de-structuration

    Un modelo conceptual sobre el funcionamiento de los ríos mediterráneos sometidos a perturbaciones naturales (riadas y sequías)

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    The Mediterranean regions are prone to suffer extraordinary flash-floods and prolonged droughts. Between these extreme events, there are small floods and droughts that are more common and more predictable. These smaller floods and droughts, along with the others mentioned before generate an extraordinarily complex temporal hydrological picture whose affects have been partly described by different authors, including those affecting the human population. The information compiled during nearly two decades by the group of Ecology of Continental Waters of the University of Murcia, about the effects of these events on rivers of the Segura River Basin, allows for elaborating a conceptual model about the function of several physical, physico-chemical, and biological parameters in rivers in the southwest, in particular and Mediterranean rivers in general.Las regiones mediterráneas son proclives a sufrir avenidas extraordinarias y sequías prolongadas. Entre estos eventos extremos, se sitúan las crecidas y estiajes más habituales y predecibles que, junto a los anteriores configuran un cuadro hidrológico temporal extraordinariamente complejo cuyos efectos han sido descritos parcialmente por diferentes autores, incluidos aquellos que afectan a la población humana. La información recogida durante casi dos décadas por el Grupo de Ecología de Aguas Continentales de la Universidad de Murcia, sobre los efectos de estos eventos en ríos de la Cuenca del Segura, permite elaborar un modelo conceptual sobre el funcionamiento de distintos parámetros físicos, físico-químicos y biológicos en ríos del sureste, en particular y mediterráneos, en general

    Differential Induction of Long-Term Potentiation in the Horizontal versus Columnar Superficial Connections to Layer II Cells of the Entorhinal Cortex

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    The entorhinal cortex (EC) is a nodal and independent mnemonic element of the medial temporal lobe memory circuit as it forms a bidirectional interface between the neocortex and hippocampus. Within the EC, intra- and inter-lamellar associational connections occur via horizontal and columnar projections, respectively. We undertook a comparative study of these two inputs as they converge upon EC layer II cells using whole-cell patch techniques in an adult rat EC horizontal slice preparation in which the deepest layers (V-VI) had been dissected out. Electrical stimulation of layers I and III during GABA blockade allowed us to study excitatory synaptic properties and plasticity in the horizontal and columnar fibre systems, respectively. Both pathways exhibited AMPA- and NMDA-receptor mediated transmission and both exhibited long-term potentiation (LTP) after high-frequency (tetanic) stimulation. LTP in the horizontal, but not in the columnar pathway, was blocked by NMDA receptor antagonism. Intriguingly, LTP in both appeared to be mediated by post synaptic increases in Ca2+ that may be coupled to differing second messenger pathways. Thus, the superficial excitatory horizontal and columnar associative pathways to layer II have divergent mechanisms for LTP which may endow the EC with even more complex and dynamic processing characteristics than previously thought
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