6,911 research outputs found

    Mobilizing agro-biodiversity and social networks to cope with adverse effects of climate and social changes: experiences from Kitui, Kenya

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    Poster presented at 13th Congress of the International Society of Ethnobiology. Montpellier (France), 20-25 May 201

    Effect of the atmosphere on the classification of LANDSAT data

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    The author has identified the following significant results. In conjunction with Turner's model for the correction of satellite data for atmospheric interference, the LOWTRAN-3 computer was used to calculate the atmospheric interference. Use of the program improved the contrast between different natural targets in the MSS LANDSAT data of Brasilia, Brazil. The classification accuracy of sugar canes was improved by about 9% in the multispectral data of Ribeirao Preto, Sao Paulo

    Global existence and full regularity of the Boltzmann equation without angular cutoff

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    We prove the global existence and uniqueness of classical solutions around an equilibrium to the Boltzmann equation without angular cutoff in some Sobolev spaces. In addition, the solutions thus obtained are shown to be non-negative and CC^\infty in all variables for any positive time. In this paper, we study the Maxwellian molecule type collision operator with mild singularity. One of the key observations is the introduction of a new important norm related to the singular behavior of the cross section in the collision operator. This norm captures the essential properties of the singularity and yields precisely the dissipation of the linearized collision operator through the celebrated H-theorem

    Well-posedness of the Viscous Boussinesq System in Besov Spaces of Negative Order Near Index s=1s=-1

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    This paper is concerned with well-posedness of the Boussinesq system. We prove that the nn (n2n\ge2) dimensional Boussinesq system is well-psoed for small initial data (u0,θ0)(\vec{u}_0,\theta_0) (u0=0\nabla\cdot\vec{u}_0=0) either in (B,11B,1,1)×Bp,r1({B}^{-1}_{\infty,1}\cap{B^{-1,1}_{\infty,\infty}})\times{B}^{-1}_{p,r} or in B,1,1×Bp,1,ϵ{B^{-1,1}_{\infty,\infty}}\times{B}^{-1,\epsilon}_{p,\infty} if r[1,]r\in[1,\infty], ϵ>0\epsilon>0 and p(n2,)p\in(\frac{n}{2},\infty), where Bp,qs,ϵB^{s,\epsilon}_{p,q} (sRs\in\mathbb{R}, 1p,q1\leq p,q\leq\infty, ϵ>0\epsilon>0) is the logarithmically modified Besov space to the standard Besov space Bp,qsB^{s}_{p,q}. We also prove that this system is well-posed for small initial data in (B,11B,1,1)×(Bn2,11Bn2,1,1)({B}^{-1}_{\infty,1}\cap{B^{-1,1}_{\infty,\infty}})\times({B}^{-1}_{\frac{n}{2},1}\cap{B^{-1,1}_{\frac{n}{2},\infty}}).Comment: 18 page

    Optical Hall Effect in the Integer Quantum Hall Regime

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    Optical Hall conductivity σxy(ω)\sigma_{xy}(\omega) is measured from the Faraday rotation for a GaAs/AlGaAs heterojunction quantum Hall system in the terahertz frequency regime. The Faraday rotation angle (\sim fine structure constant \sim mrad) is found to significantly deviate from the Drude-like behavior to exhibit a plateau-like structure around the Landau-level filling ν=2\nu=2. The result, which fits with the behavior expected from the carrier localization effect in the ac regime, indicates that the plateau structure, although not quantized, still exists in the terahertz regime.Comment: 4 pages, 4 figure

    Lipschitz shadowing implies structural stability

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    We show that the Lipschitz shadowing property of a diffeomorphism is equivalent to structural stability. As a corollary, we show that an expansive diffeomorphism having the Lipschitz shadowing property is Anosov.Comment: 11 page

    Relationship Between Output of a Fluxgate Sensor and Magnetization Process of Its Core

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    Motivated by the need to miniaturize fluxgate sensors, we investigated the dependence of the sensitivity of fluxgate sensors on the saturation flux density and magnetostriction of an amorphous ribbon core. In addition, the relationship between the sensing properties and the magnetization process of its core was investigated with a Kerr microscope. We found that the sensitivity decreased with an increase in magnetostriction. Highly magnetostrictive amorphous ribbons exhibited maze domains that were difficult to move by applying a low magnetic field of a few hundred amperes per meter. This effect caused a decrease in the sensitivity of the sensors

    Coherent states on spheres

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    We describe a family of coherent states and an associated resolution of the identity for a quantum particle whose classical configuration space is the d-dimensional sphere S^d. The coherent states are labeled by points in the associated phase space T*(S^d). These coherent states are NOT of Perelomov type but rather are constructed as the eigenvectors of suitably defined annihilation operators. We describe as well the Segal-Bargmann representation for the system, the associated unitary Segal-Bargmann transform, and a natural inversion formula. Although many of these results are in principle special cases of the results of B. Hall and M. Stenzel, we give here a substantially different description based on ideas of T. Thiemann and of K. Kowalski and J. Rembielinski. All of these results can be generalized to a system whose configuration space is an arbitrary compact symmetric space. We focus on the sphere case in order to be able to carry out the calculations in a self-contained and explicit way.Comment: Revised version. Submitted to J. Mathematical Physic
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