An investigation of the SNS Josephson junction as a three-terminal device

A particular phenomenon of the SNS Josephson junction was investigated; i.e., control by a current entering the normal region and leaving through one of the superconducting regions. The effect of the control current on the junction was found to be dependent upon the ration of the resistances of the two halves of the N layer. A low frequency, lumped, nonlinear model was proposed to describe the electrical characteristics of the device, and a method was developed to plot the dynamic junction resistance as a function of junction current. The effective thermal noise temperature of the sample was determined. Small signal linearized analysis of the device suggests its use as an impedance transformer, although geometric limitations must be overcome. Linear approximation indicates that it is reciprocal and no power gain is possible. It is felt that, with suitable metallurgical and geometrical improvements, the device has promise to become a superconducting transistor

Structures in the microwave background radiation

We compare the actual WMAP maps with artificial, purely statistical maps of the same harmonic content to argue that there are, with confidence level 99.7 %, ring-type structures in the observed cosmic microwave background.Comment: 4 pages, 2 figure

Constructing Phantom Cosmologies from Standard Scalar Field Universes

We illustrate how form-invariance transformations can be used for constructing phantom cosmologies from standard scalar field universes. First, we discuss how to relate two flat Friedmann-Robertson-Walker cosmologies with different barotropic indexes $\gamma$ and $\bar \gamma$. Then, we consider the particular case $\bar \gamma=-\gamma$, and we show that if the matter content is interpreted in terms of self-interacting scalar fields, then the corresponding transformation provides the link between a standard and a phantom cosmology. After that, we illustrate the method by considering models with exponential potentials. Finally, we also show that the mentioned duality persists even if the typical braneworld modifications to the Friedmann equation are considered.Comment: 3 pages, revtex4, new title and minor changes in the main text and references to match published versio

1/Nc1/N_c Rotational Corrections to gAg_A and Isovector Magnetic Moment of the Nucleon

The $1/N_c$ rotational corrections to the axial vector constant and the isovector magnetic moment of the nucleon are studied in the Nambu -- Jona-Lasinio model. We follow a semiclassical quantization procedure in terms of path integrals in which we can include perturbatively corrections in powers of angular velocity $\Omega \sim \frac 1{N_c}$. We find non-zero $1/N_c$ order corrections from both the valence and the Dirac sea quarks. These corrections are large enough to resolve the long-standing problem of a strong underestimation of both $g_A$ and $\mu^{IV}$ in the leading order. The axial constant $g_A$ is well reproduced, whereas the isovector magnetic moment $\mu^{IV}$ is still underestimated by 25 \%.Comment: (Revtex), 10 pages (3 figures available on request), report RUB-TPII-53/9

Mamoeiro transgênico no Brasil: resultados obtidos e legislação para sua liberação.

No Brasil, em março de 2005, a Lei nº 11.105 entre outras medidas, estabeleceu as normas de segurança e mecanismos de fiscalização de atividades que envolvam organismos geneticamente modificados (OGM) e seus derivados, criou o Conselho Nacional de Biossegurança (CNBS), reestruturou a Comissão Técnica Nacional de Biossegurança (CTNBio), dispôs sobre a Política Nacional de Biossegurança (PNB) e revogou a Lei de biossegurança anterior, a Lei Nº 8.974 (CTNBio, 2011)

Indexação de plantas para viroses.

No mundo há milhares de viroses descritas, cada uma possuindo uma específica gama de hospedeiros. A sintomatologia produzida varia bastante, dependendo do vírus ou da estirpe presente, da planta infectada e das condições do ambiente. No Brasil, em fruteiras tropicais, citros e mandioca já se constatou a ocorrência de várias viroses, como o vírus associado com a murcha do abacaxi, o vírus das estrias da bananeira, o vírus da meleira do mamoeiro, o vírus da tristeza dos citros e o vírus do mosaico das nervuras da mandioca. Na natureza, a maioria das viroses são transmitidas por insetos, mas também é comum sua transmissão por sementes, manivas ou enxertos obtidos de plantas infectadas. As ferramentas de corte contaminadas também podem propiciar a disseminação de algumas viroses.bitstream/item/25859/1/http-agrosoft.comID27016-pdf.pdfDisponível em : Acesso em : 24 jan. 2011

Viroses da bananeira.

A cultura da bananeira pode ser infectada por diversas viroses, como o vírus do topo em leque da bananeira, o vírus das estrias da bananeira, o vírus do mosaico do pepino, o vírus do mosaico das brácteas da bananeira, o Banana mild mosaic virus, o Banana virus X, o Abaca bunchy top virus e o Sugarcane mosaic virus. No Brasil, até o momento foram relatados o vírus do mosaico do pepino e o vírus das estrias da bananeira.bitstream/item/25824/1/Meissner-agrosoft.com-pdf.pdfDisponível em: Acesso em: 20 jan. 2011