1,821 research outputs found

    Two-scale convergence for locally-periodic microstructures and homogenization of plywood structures

    Full text link
    The introduced notion of locally-periodic two-scale convergence allows to average a wider range of microstructures, compared to the periodic one. The compactness theorem for the locally-periodic two-scale convergence and the characterisation of the limit for a sequence bounded in H1(Ω)H^1(\Omega) are proven. The underlying analysis comprises the approximation of functions, which periodicity with respect to the fast variable depends on the slow variable, by locally-periodic functions, periodic in subdomains smaller than the considered domain, but larger than the size of microscopic structures. The developed theory is applied to derive macroscopic equations for a linear elasticity problem defined in domains with plywood structures.Comment: 22 pages, 4 figure

    Watermelon stomach seen by wireless‐capsule endoscopy

    Get PDF
    Endoscopy. 2003 Jan;35(1):100. Watermelon stomach seen by wireless-capsule endoscopy. Mascarenhas-Saraiva M, Lopes L, Mascarenhas-Saraiva A. SourceDigestive Endoscopy and Motility Unit, Trindade Hospital, Rua Trinidade 115, 4000-541 Porto, Portugal. [email protected] PMID:12510242[PubMed - indexed for MEDLINE

    Camparaçāo entre os cruzeiros de investigaçāo realizados no Banco de Sofala pelo navio SRTM "Sebastopolsky rybak" em Setembro-Outubro e Novembro-Dezembro de 1982: camarao de [águas pouco profundas]

    Get PDF
    During the last 4 months of 1982, two research cruises had been carried out at the Sofala Bank by the SRTM "Sevastopolsky Rybak". The authors analyze and compare data on biological characteristics, sexual maturity and localization of Penaeus indicus and Metapenaeus monoceros

    Penaeus indicus H. Milne Edwards, 1837: resumo das conclusões dos cruzeiros de pesca exploratória entre 1979 e 1983 no banco de Sofala em Moçambique

    Get PDF
    From 1979 to 1983, several surveys were carried out with research and fishing vessels at Sofala Bank in Mozambique. Their main objective was the assessment of shallow water prawn stocks, as this resource is of great economic importance for the country. A summary of the conclusions of these surveys regarding the species Penaeus indicus is presented. During the rainy season the species occurs closer to the shore than during the dry season. Estimates of biomass are very variable. The spawning peak seems to occur at the beginning of the rainy season (September-October). The spawning areas are located very close to the shore in the northern part of Sofala Bank and South of 17 degree 10'S in the 15-25 m depth interval

    A Fabry-Perot interferometer with quantum mirrors: nonlinear light transport and rectification

    Full text link
    Optical transport represents a natural route towards fast communications, and it is currently used in large scale data transfer. The progressive miniaturization of devices for information processing calls for the microscopic tailoring of light transport and confinement at length scales appropriate for the upcoming technologies. With this goal in mind, we present a theoretical analysis of a one-dimensional Fabry-Perot interferometer built with two highly saturable nonlinear mirrors: a pair of two-level systems. Our approach captures non-linear and non-reciprocal effects of light transport that were not reported previously. Remarkably, we show that such an elementary device can operate as a microscopic integrated optical rectifier

    Evaluation of entropy and JM-distance criterions as features selection methods using spectral and spatial features derived from LANDSAT images

    Get PDF
    A study area near Ribeirao Preto in Sao Paulo state was selected, with predominance in sugar cane. Eight features were extracted from the 4 original bands of LANDSAT image, using low-pass and high-pass filtering to obtain spatial features. There were 5 training sites in order to acquire the necessary parameters. Two groups of four channels were selected from 12 channels using JM-distance and entropy criterions. The number of selected channels was defined by physical restrictions of the image analyzer and computacional costs. The evaluation was performed by extracting the confusion matrix for training and tests areas, with a maximum likelihood classifier, and by defining performance indexes based on those matrixes for each group of channels. Results show that in spatial features and supervised classification, the entropy criterion is better in the sense that allows a more accurate and generalized definition of class signature. On the other hand, JM-distance criterion strongly reduces the misclassification within training areas

    Investigations of fast neutron production by 190 GeV/c muon interactions on different targets

    Get PDF
    The production of fast neutrons (1 MeV - 1 GeV) in high energy muon-nucleus interactions is poorly understood, yet it is fundamental to the understanding of the background in many underground experiments. The aim of the present experiment (CERN NA55) was to measure spallation neutrons produced by 190 GeV/c muons scattering on carbon, copper and lead targets. We have investigated the energy spectrum and angular distribution of spallation neutrons, and we report the result of our measurement of the neutron production differential cross section.Comment: 19 pages, 11 figures ep

    Equilibrium and Disorder-induced behavior in Quantum Light-Matter Systems

    Full text link
    We analyze equilibrium properties of coupled-doped cavities described by the Jaynes-Cummings- Hubbard Hamiltonian. In particular, we characterize the entanglement of the system in relation to the insulating-superfluid phase transition. We point out the existence of a crossover inside the superfluid phase of the system when the excitations change from polaritonic to purely photonic. Using an ensemble statistical approach for small systems and stochastic-mean-field theory for large systems we analyze static disorder of the characteristic parameters of the system and explore the ground state induced statistics. We report on a variety of glassy phases deriving from the hybrid statistics of the system. On-site strong disorder induces insulating behavior through two different mechanisms. For disorder in the light-matter detuning, low energy cavities dominate the statistics allowing the excitations to localize and bunch in such cavities. In the case of disorder in the light- matter coupling, sites with strong coupling between light and matter become very significant, which enhances the Mott-like insulating behavior. Inter-site (hopping) disorder induces fluidity and the dominant sites are strongly coupled to each other.Comment: about 10 pages, 12 figure

    Unexpected angiographic and visual findings after clipping of a carotid-ophthalmic aneurysm

    Get PDF
    A 56-year-old woman underwent surgery for a ruptured carotid-ophthalmic artery aneurysm. Intraoperative visual inspection confirmed that the ophthalmic artery was left intact. She had no light perception on the operated side right after surgery. Angiography one week after surgery confirmed exclusion of the aneurysm, no filling of the proximal portion of the ophthalmic artery, and a very faint filling of its distal orbital part. She gradually recovered from this deficit and 9 months after surgery she is capable of counting fingers. At this time angiography displayed filling of all the portions of the ophthalmic artery, absence of recruitment of collateral blood supply, and exclusion of the aneurysm as before. Surgical manipulation seems to either have induced vasospasm or thrombosis of the ophthalmic artery. Regression of vasospasm or secondary recanalization of the thrombus without development of collateral blood supply may account for the gradual improvement of vision. A risk of monocular blindness is associated with the surgical treatment of para-clinoid aneurysms. Nevertheless, when it occurs, a perspective of recovery may exist if certain etiologies are involved
    corecore