Agroecological transitions in scientific research programs in Brazil and France.

n. 0622

Pairbreaking Without Magnetic Impurities in Disordered Superconductors

We study analytically the effects of inhomogeneous pairing interactions in short coherence length superconductors, using a spatially varying Bogoliubov-deGennes model. Within the Born approximation, it reproduces all of the standard Abrikosov-Gor'kov pairbreaking and gaplessness effects, even in the absence of actual magnetic impurities. For pairing disorder on a single site, the T-matrix gives rise to bound states within the BCS gap. Our results are compared with recent scanning tunneling microscopy measurements on Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ with Zn or Ni impurities.Comment: 4 pages, 2 figures, submitted to PR

Contribuição à melhoria na produção junto à agricultura familiar, povos indígenas e populações tradicionais.

A produção agrícola dos segmentos sociais contemplados neste capítulo - agricultores familiares, povos indígenas e populações tradicionais - tem características, significados e desafios distintos dos demais segmentos produtivos do setor agrícola brasileiro. Demandam diagnósticos e reflexões adequadas quanto ao seu significado nas diferentes realidades econômicas, sociais, políticas, culturais e ambientais para, assim, poder abordar estratégias de aumento de produção

Charged Magnetic Brane Solutions in AdS_5 and the fate of the third law of thermodynamics

We construct asymptotically AdS_5 solutions to 5-dimensional Einstein-Maxwell theory with Chern-Simons term which are dual to 4-dimensional gauge theories, including N=4 SYM theory, in the presence of a constant background magnetic field B and a uniform electric charge density \rho. For the solutions corresponding to supersymmetric gauge theories, we find numerically that a small magnetic field causes a drastic decrease in the entropy at low temperatures. The near-horizon AdS_2 \times R^3 geometry of the purely electrically charged brane thus appears to be unstable under the addition of a small magnetic field. Based on this observation, we propose a formulation of the third law of thermodynamics (or Nernst theorem) that can be applied to black holes in the AdS/CFT context. We also find interesting behavior for smaller, non-supersymmetric, values of the Chern-Simons coupling k. For k=1 we exhibit exact solutions corresponding to warped AdS_3 black holes, and show that these can be connected to asymptotically AdS_5 spacetime. For k\leq 1 the entropy appears to go to a finite value at extremality, but the solutions still exhibit a mild singularity at strictly zero temperature. In addition to our numerics, we carry out a complete perturbative analysis valid to order B^2, and find that this corroborates our numerical results insofar as they overlap.Comment: 45 pages v2: added note about subsequent results found in arXiv:1003.130

Parity Violating Gravitational Coupling Of Electromagnetic Fields

A manifestly gauge invariant formulation of the coupling of the Maxwell theory with an Einstein Cartan geometry is given, where the space time torsion originates from a massless Kalb-Ramond field augmented by suitable U(1) Chern Simons terms.We focus on the situation where the torsion violates parity, and relate it to earlier proposals for gravitational parity violation.Comment: 7 Pages, Latex . no figures, Replaced with Revtex version, many references added and typos correcte

Knock-down of heat-shock protein 90 and isocitrate lyase gene expression reduced root-knot nematode reproduction.

Made available in DSpace on 2018-07-19T01:01:42Z (GMT). No. of bitstreams: 1 PHYTO09140237R.pdf: 775087 bytes, checksum: 95edcbc8a1ffecb0dac1b523acf37dd6 (MD5) Previous issue date: 2015-09-14bitstream/item/129546/1/PHYTO-09-14-0237-R.pd