1,149 research outputs found

    Scenario-based modeling in industrial information systems

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    This manuscript addresses the creation of scenario-based models to reason about the behavior of existing industrial information systems. In our approach the system behavior is modeled in two steps that gradually introduce detail and formality. This manuscript addresses the first step, where text-based descriptions, in the form of structured rules, are used to specify how the system is or should be regulated. Those rules can be used to create behavioral snapshots, which are collections of scenario-based descriptions that represent different instances of the system behavior. Snapshots are specified in an intuitive and graphical notation that considers the elements from the problem domain and permit designers to discuss and validate the externally observable behavior, together with the domain experts. In the second step (not fully covered in this manuscript), the system behavior is formalized with an executable model. This formal model, which in our approach is specified using the Colored Petri Net (CP-nets) language, allows the system internal behavior to be animated, simulated, and optimized. The insights gained by experimenting with the formal model can be subsequently used for reengineering the existing system

    Hippocampal Insulin Signaling And Neuroprotection Mediated By Physical Exercise In Alzheimeŕs Disease

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    Epidemiological studies indicate continuous increases in the prevalence of Alzheimer's Disease (AD) in the next few decades. The key feature of this disease is hippocampal neurodegeneration. This structure has an important role in learning and memory. Intense research efforts have sought to elucidate neuroprotective mechanisms responsible for hippocampal integrity. Insulin signaling seems to be a very promising pathway for the prevention and treatment of AD. This hormone has been described as a powerful activator of neuronal survival. Recent research showed that reduced insulin sensitivity leads to low-grade inflammation, and both phenomena are closely related to AD genesis. Concomitantly, exercise has been shown to exert anti-inflammatory effects and to promote improvement in insulin signaling in the hippocampus, which supports neuronal survival and constitutes an interesting non-pharmacological alternative for the prevention and treatment of AD. This review examines recent advances in understanding the molecular mechanisms involved in hippocampal neuroprotection mediated by exercise.2

    Large scale numerical investigation of excited states in poly(phenylene)

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    A density matrix renormalisation group scheme is developed, allowing for the first time essentially exact numerical solutions for the important excited states of a realistic semi-empirical model for oligo-phenylenes. By monitoring the evolution of the energies with chain length and comparing them to the experimental absorption peaks of oligomers and thin films, we assign the four characteristic absorption peaks of phenyl-based polymers. We also determine the position and nature of the nonlinear optical states in this model.Comment: RevTeX, 10 pages, 4 eps figures included using eps

    Noncommutative massive Thirring model in three-dimensional spacetime

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    We evaluate the noncommutative Chern-Simons action induced by fermions interacting with an Abelian gauge field in a noncommutative massive Thirring model in (2+1)-dimensional spacetime. This calculation is performed in the Dirac and Majorana representations. We observe that in Majorana representation when θ\theta goes to zero we do not have induced Chern-Simons term in the dimensional regularization scheme.Comment: Accepted to Phys. Rev. D; 9 pages, Revtex4, no figures, references added, minor improvements, Eq.31 correcte

    The low energy limit of the non-commutative Wess-Zumino model

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    The non-commutative Wess-Zumino model is used as a prototype for studying the low energy behaviour of a renormalizable non-commutative field theory. We start by deriving the potential mediating the fermion-fermion and boson-boson interactions in the non-relativistic regime. The quantum counterparts of these potentials are afflicted by irdering ambiguities but we show that there exists an ordering prescription which makes them hermitean. For space/space noncommutativity it turns out that Majorana fermions may be pictured as rods oriented perpendicularly to the direction of motion showing a lack of localituy, while bosons remain insensitive to the effects of noncommutativity. For time/space noncommutativity bosopns and fermions can be regarded as rods oriented along the direction of motion. For both cases of noncommutativity the scattering state described scattered waves, with at least one wave having negative time delay signalizing the underlying nonlocality. The superfield formulation of the model is used to compute the corresponding effective action in the one- and two-loop approximations. In the case of time/space noncommutativity, unitarity is violated in the relativistic regime. However, this does not preclude the existence of the unitary low energy limit.Comment: 14 pages, 2 figures, minor correction

    Climatology, bioclimatology and vegetation cover: tools to mitigate climate change in olive groves

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    19 páginas, 10 figuras, 3 tablas.This work establishes the relationship between bioclimatology and agronomy. Bioclimatic indices are obtained for several areas under olive cultivation and correlated with olive yields. Due to the effect of climate change on cultivation and the high economic losses it produces, we propose a sustainable development model for the territorial classification of crops based on bioclimatic knowledge. Bioclimatic diagrams are prepared to provide information on water stress in crops so that irrigation can be carried out at the most effective time, a measure that has been shown to lead to water and energy savings for growers. In addition to this development model, we propose the application of non-aggressive cultivation techniques such as the use of living plant cover to ensure the protection of the soil and avoid losses due to climate irregularities. Studies conducted up to the present on applied bioclimatology have yielded promising results in the fields of farming and forestry. The maps and bioclimatic indices of Professor Rivas-Martínez, Ic, Io and It/Itc, are essential for bioclimatic classification. The agricultural development model with a bioclimatic basis ensures economic savings for growers and minimizes the environmental impact of cultivation. In the case of olive cultivation we detected that in 2005 all the cultivated areas that were not in their thermoclimatic optimum were damaged by frost. The widespread cultivation of olive groves in the Mediterranean basin, and mainly in the south of Spain, is reason enough to establish a relationship between its production and its bioclimatic environment. The ombroclimatic study in certain localities under olive cultivation shows that areas with Io <2.5 are unproductive (Jodar, Tabernas), and that their low Io value needs to be supplemented with irrigation water. This means extracting water from aquifers for agricultural use, when the current climate irregularities do not allow the excessive use of subsoil water. For the time being the only way of mitigating this situation is with sustainable development, which requires a bioclimatic understanding of the territory; and the use of appropriate cultivation techniques, including herbaceous plant covers. In this last case a knowledge of the plant associations in the phytosociological class Stellarietea mediae constitutes the basis for establishing either natural or sown vegetation cover

    An algorithm to discover the k-clique cover in networks

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    In social network analysis, a k-clique is a relaxed clique, i.e., a k-clique is a quasi-complete sub-graph. A k-clique in a graph is a sub-graph where the distance between any two vertices is no greater than k. The visualization of a small number of vertices can be easily performed in a graph. However, when the number of vertices and edges increases the visualization becomes incomprehensible. In this paper, we propose a new graph mining approach based on k-cliques. The concept of relaxed clique is extended to the whole graph, to achieve a general view, by covering the network with k-cliques. The sequence of k-clique covers is presented, combining small world concepts with community structure components. Computational results and examples are presented

    Excluded Volume Effects in the Quark Meson Coupling Model

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    Excluded volume effects are incorporated in the quark meson coupling model to take into account in a phenomenological way the hard core repulsion of the nuclear force. The formalism employed is thermodynamically consistent and does not violate causality. The effects of the excluded volume on in-medium nucleon properties and the nuclear matter equation of state are investigated as a function of the size of the hard core. It is found that in-medium nucleon properties are not altered significantly by the excluded volume, even for large hard core radii, and the equation of state becomes stiffer as the size of the hard core increases.Comment: 14 pages, revtex, 6 figure

    Search for the Rare Decay KL --> pi0 ee

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    The KTeV/E799 experiment at Fermilab has searched for the rare kaon decay KL--> pi0ee. This mode is expected to have a significant CP violating component. The measurement of its branching ratio could support the Standard Model or could indicate the existence of new physics. This letter reports new results from the 1999-2000 data set. One event is observed with an expected background at 0.99 +/- 0.35 events. We set a limit on the branching ratio of 3.5 x 10^(-10) at the 90% confidence level. Combining the results with the dataset taken in 1997 yields the final KTeV result: BR(KL --> pi0 ee) < 2.8 x 10^(-10) at 90% CL.Comment: 4 pages, three figure
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