400 research outputs found

    Singular quasilinear elliptic systems in RN\mathbb{R}^N

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    The existence of positive weak solutions to a singular quasilinear elliptic system in the whole space is established via suitable a priori estimates and Schauder's fixed point theorem

    A class of second order BVPs on infinite intervals

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    In this work, we are concerned with a boundary value problem associated with a generalized Fisher-like equation. This equation involves an eigenvalue and a parameter which may be viewed as a wave speed. According to the behavior of the nonlinear source term, existence results of bounded solutions, positive solutions, classical as well as weak solutions are provided. We mainly use fixed point arguments

    Boundary value problems for doubly perturbed first order ordinary differential systems

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    The aim of this paper is to present new results on existence theory for perturbed BVPs for first order ordinary differential systems. A nonlinear alternative for the sum of a contraction and a compact mapping is used

    EFFECT OF Salsola vermiculata

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    Algerian aride zone is rich with medicinal plant, Salsola vermiculata is one of the mosttraditional plant remedies in Bechar region. in this work, we tried to test the inhibitory effect on eight storage soft wheat fungi of various extracts of Salsola vermiculata in vitro and vivo by using grain storage by the coating method. The phytochemical screening of plants showed the detection of tannins, saponisides and flavonoids. The results show a remarkable antifungal effect by most of the extracts tested. The  decrease in the level of fungi observed in wheat samples demonstrates the effectiveness of grain storage by the coating method.Keywords: Salsola vermiculata; Antifungal activity; Coating method; Fungi; soft wheat;Storage

    360 degree domain wall generation in the soft layer of magnetic tunnel junctions

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    High spatial resolution X-ray photo-emission electron microscopy technique has been used to study the influence of the dipolar coupling taking place between the NiFe and the Co ferromagnetic electrodes of micron sized, elliptical shaped magnetic tunnel junctions. The chemical selectivity of this technique allows to observe independently the magnetic domain structure in each ferromagnetic electrode. The combination of this powerful imaging technique with micromagnetic simulations allows to evidence that a 360 degree domain wall can be stabilized in the NiFe soft layer. In this letter, we discuss the origin and the formation conditions of those 360 degree domain walls evidenced experimentally and numerically

    MCMC Algorithms for Supervised and Unsupervised Linear Unmixing of Hyperspectral Images

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    This book is a collection of 19 articles which reflect the courses given at the Collège de France/Summer school “Reconstruction d'images − Applications astrophysiques“ held in Nice and Fréjus, France, from June 18 to 22, 2012. The articles presented in this volume address emerging concepts and methods that are useful in the complex process of improving our knowledge of the celestial objects, including Earth

    Artificial Kagome Arrays of Nanomagnets: A Frozen Dipolar Spin Ice

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    Magnetic frustration effects in artificial kagome arrays of nanomagnets are investigated using x-ray photoemission electron microscopy and Monte Carlo simulations. Spin configurations of demagnetized networks reveal unambiguous signatures of long range, dipolar interaction between the nanomagnets. As soon as the system enters the spin ice manifold, the kagome dipolar spin ice model captures the observed physics, while the short range kagome spin ice model fails.Comment: 4 pages, 4 figures, 1 tabl

    Extracción de aceite de orujo de aceituna con hexano ácido

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    The use of acidic hexane as a solvent increases the extracted oil yield from olive foot cake. Two extraction procedures are studied: open air extraction at room temperature and Soxhlet exhaustive extraction. The additional yield is about 5% for a 2.5% acetic acid content in case of open air extraction and turns out to be 9% for 7.5% acetic acid content in the Soxhlet procedure. An analysis of the extracted oil shows a light increase of the acidity of oil. The improved yield may be attributed to the action of acetic acid on the decomposition of intercellular structures and binding of some polar lipids. The phospholipids content of oil extracted with 7.5% acidic hexane is found to be 25 times more than with pure hexane.El uso de hexano ácido como disolvente aumenta el rendimiento de aceite extraído de orujo de aceituna. Se han estudiado dos procedimientos de extracción: extracción al aire libre a temperatura ambiente y extracción exhaustiva en Soxhlet. En el caso de extracción al aire libre el rendimiento adicional es alrededor del 5% para un contenido del 2'5% en ácido acético y llega a ser en el procedimiento en Soxhlet del 9% para un contenido en ácido acético del 7'5%. Un análisis del aceite extraído mostró un ligero aumento de la acidez del aceite. La mejora del rendimiento puede ser atribuida a la acción del ácido acético sobre la descomposición de estructuras intercelulares y uniones de lípidos polares. Se ha encontrado que el contenido en fosfolípidos del aceite extraído con el 7*5% de hexano ácido es 25 veces mayor que con hexano puro
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