6,570 research outputs found

    Optimal cutting directions and rectangle orientation algorithm

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    The first stage in hierarchical approaches to Floorplan Design defines topological relations between components that intend to optimize a given objective in a circuit board. These relations determine a placement that is subsequently optimized in order to minimize a cost measurement (that will probably be one between chip area or perimeter). The board optimization gives rise to multiple subproblems that need to be answered in order to obtain a good solution. Among the most relevant ones we find the problem of defining the optimal orientation of cells and the definition of the optimal cutting sequence that minimize the placement board area. We will present a generalization of an algorithm due to Stockmeyer so that it obtains a solution that not only defines the optimal cell orientation but also the slicing cuts sequence that will lead to this optimal orientation and overall area minimization.http://www.sciencedirect.com/science/article/B6VCT-3TN9R05-B/1/3ed2fa5acf5e53dff08af5423738ac8

    A variational approach for the Quantum Inverse Scattering Method

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    We introduce a variational approach for the Quantum Inverse Scattering Method to exactly solve a class of Hamiltonians via Bethe ansatz methods. We undertake this in a manner which does not rely on any prior knowledge of integrability through the existence of a set of conserved operators. The procedure is conducted in the framework of Hamiltonians describing the crossover between the low-temperature phenomena of superconductivity, in the Bardeen-Cooper-Schrieffer (BCS) theory, and Bose-Einstein condensation (BEC). The Hamiltonians considered describe systems with interacting Cooper pairs and a bosonic degree of freedom. We obtain general exact solvability requirements which include seven subcases which have previously appeared in the literature.Comment: 18 pages, no eps figure

    Integrable variant of the one-dimensional Hubbard model

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    A new integrable model which is a variant of the one-dimensional Hubbard model is proposed. The integrability of the model is verified by presenting the associated quantum R-matrix which satisfies the Yang-Baxter equation. We argue that the new model possesses the SO(4) algebra symmetry, which contains a representation of the η\eta-pairing SU(2) algebra and a spin SU(2) algebra. Additionally, the algebraic Bethe ansatz is studied by means of the quantum inverse scattering method. The spectrum of the Hamiltonian, eigenvectors, as well as the Bethe ansatz equations, are discussed

    Vortex guide under a Lorentz force.

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    In the present work we study the effect that the metallic quality of the contacts by which an external current is applied, has onthe magnetic properties of a superconducting sample. We analyze the magnetization, magnetic susceptibility, Cooper pair density as appliedmagnetic field function. The contacts are simulated using th

    Avaliação de dietas contendo farelo de mandioca e palma forrageira por meio do teor de uréia no soro de ovinos.

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    Neste trabalho foi avaliada a substituição do farelo de mandioca pelo farelo de palma forrageira através do teor de uréia no soro. Foram utilizados 20 ovinos, machos, não castrados, mestiços da raça Santa Inês, com idade média de nove meses e com peso médio de 20,0 +-: 4,0 kg. Utilizaram-se os ingredientes feno de capim buffel amoniado com uréia a 4%, farelo de palma e farelo de mandioca. Os níveis de substituição da raspa de mandioca pelo farelo de palma foram de 0, 25, 50, 75 e 100%, representando os tratamentos. O delineamento experimental foi o de blocos ao acaso com quatro repetições e cinco tratamentos. Procederam-se quatro coletas de sangue. O teor de uréia no soro apresentou comportamento linear em relação ao CMS e o CPB. O teor de uréia no soro mostrou-se um eficiente monitor das dietas propostas, porém deve ser utilizado em conjunto com outras formas de avaliação com o intuito de se alcançar um eficiente manejo alimentar de ruminantes

    Topological defects and open inflation

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    Topological defects can naturally be formed soon after bubble nucleation in the open inflation scenario. The defects are not completely diluted away by the subsequent period of inflation in the bubble interior and can produce observable large-scale microwave background anisotropies. Superheavy strings and monopoles attached to the strings can act as gravitational lenses with angular separation between the images of up to an arc minute.Comment: 11 pages, revte

    Transcriptome analysis in response to gradual water deficit in Arachis wild relatives.

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    Peanut (cultivated tetraploid Arachis hypogaea) is an important food legume widely cultivated mainly in Asia, Africa and the Americas although its productivity is limited in drought-prone areas; therefore the development of drought-resistant varieties is a priority. Peanut has a narrow genetic diversity and is reproductively isolated from its wild diploid relatives due to ploidy differences. In contrast to peanut, wild relatives have higher genetic diversity and show adaptation to a range of environments thus constituting a rich source of allele diversity for resistance to biotic and tolerance to abiotic stresses. In this study, the transcriptomes of two wild diploids, A. duranensis and A. magna, representatives of the AA and BB peanut component genomes respectively, were analyzed under gradual water deficit. Two SSH libraries produced from roots of A. magna generated 759 Sanger ESTs with 249 Unigenes, whilst from A. duranensis roots, 380,601 Roche/454 reads resulted in12,792 Unigenes. Forty-six Unigenes were selected as drought-related candidates for validation by RT-qPCR by in silico analysis of all libraries. A total of 18 candidate genes showed significantly different levels of expression in stressed plants, confirming their involvement in drought response. To date, this is the first report on global gene expression profile of wild Arachis species submitted to an abiotic stress. Data produced in this study is a valuable resource for gene identification, characterization of new alleles and development of molecular markers in Arachis

    Translational neurophysiology in sheep:Measuring sleep and neurological dysfunction in CLN5 affected Batten disease sheep

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    This is the final published version of a paper originally published in BRAIN 2015: 138; 862?874, DOI: http://dx.doi.org/10.1093/brain/awv026Creating valid mouse models of slowly progressing human neurological diseases is challenging, not least because the short lifespan of rodents confounds realistic modelling of disease time course. With their large brains and long lives, sheep offer significant advantages for translational studies of human disease. Here we used normal and CLN5 Batten disease affected sheep to demonstrate the use of the species for studying neurological function in a model of human disease. We show that electroencephalography can be used in sheep, and that longitudinal recordings spanning many months are possible. This is the first time such an electroencephalography study has been performed in sheep. We characterized sleep in sheep, quantifying characteristic vigilance states and neurophysiological hallmarks such as sleep spindles. Mild sleep abnormalities and abnormal epileptiform waveforms were found in the electroencephalographies of Batten disease affected sheep. These abnormalities resemble the epileptiform activity seen in children with Batten disease and demonstrate the translational relevance of both the technique and the model. Given that both spontaneous and engineered sheep models of human neurodegenerative diseases already exist, sheep constitute a powerful species in which longitudinal in vivo studies can be conducted. This will advance our understanding of normal brain function and improve our capacity for translational research into neurological disorders.This work was funded by CHDI Inc. (AJM). Founding the\ud sheep flock, and costs in NZ relating to the rearing and\ud genotyping of the animals were funded by a series of grants\ud from the Neurological Foundation of NZ and the Batten\ud Disease Support and Research Association (DNP, NLM)
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