Anisotropic superconducting properties of aligned MgB2 crystallites

Samples of aligned MgB2 crystallites have been prepared, allowing for the first time the direct identification of an upper critical field anisotropy Hc2^{ab}/Hc2^{c}= xi_{ab}/xi_{c} ~ 1.73; with xi_{o,ab} ~ 70 A, xi_{o,c} ~ 40 A, and a mass anisotropy ratio m_{ab}/m_{c} ~ 0.3. A ferromagnetic background signal was identified, possibly related to the raw materials purity.Comment: 4 pages, 4 figures; Revised version to appear in Phys. Rev. Let

Irreversible magnetization under rotating fields and lock-in effect on ErBa_2Cu_3O_7 single crystal with columnar defects

We have measured the irreversible magnetization M_i of an ErBa_2Cu_3O_7 single crystal with columnar defects (CD), using a technique based on sample rotation under a fixed magnetic field H. This method is valid for samples whose magnetization vector remains perpendicular to the sample surface over a wide angle range - which is the case for platelets and thin films - and presents several advantages over measurements of M_L(H) loops at fixed angles. The resulting M_i(\Theta) curves for several temperatures show a peak in the CD direction at high fields. At lower fields, a very well defined plateau indicative of the vortex lock-in to the CD develops. The H dependence of the lock-in angle \phi_L follows the H^{-1} theoretical prediction, while the temperature dependence is in agreement with entropic smearing effects corresponding to short range vortex-defects interactions.Comment: 7 pages, 6 figures, to be published in Phys. Rev.

Levantamento da ocorrência de potato virus A, potato virus Y e potato leafroll virus em áreas produtoras de batata do Estado de Minas Gerais.

Considerando a importancia dos vírus paa a cultura da batateira realizou-se, no período de 13 a 16 de julho de 2012, levantamento de ocorrencia do PVY e do PLRV em 13 campos de produção de batata em cinco municípios de sul do Estado de Minas Gerais e da região do Alto Paranaíba.Resumo 119

Aumento da vida de prateleira de goiaba utilizando tratamento com radiação ionizante.

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Cria e recria das poedeiras coloniais Embrapa 051.

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Pinteiros cobertos - estufas para a redução da síndrome ascítica em frangos de corte.

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Cria e recria das poedeiras de ovos castanhos Embrapa 031.

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Produção de ovos das poedeiras de ovos castanhos Embrapa 031.

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