Perspectivas da bubalinocultura no Baixo Madeira no estado de Rondonia.

Estudo preliminar visando suprir deficiencia de carne e leite dos moradores das margens do Rio Madeira. Envolve aspectos relativos a bubalinocultura, operacoes que formam o sistema, producao de leite, instalacoes, comercializacao e sugestoes para o fomento da bubalinocultura.bitstream/item/55121/1/Circ.tecn-03-0001.pd

Superconformal Black Hole Quantum Mechanics

In recent work, the superconformal quantum mechanics describing D0 branes in the AdS_2xS^2xCY_3 attractor geometry of a Calabi-Yau black hole with D4 brane charges p^A has been constructed and found to contain a large degeneracy of chiral primary bound states. In this paper it is shown that the asymptotic growth of chiral primaries for N D0 branes exactly matches the Bekenstein-Hawking area law for a black hole with D4 brane charge p^A and D0 brane charge N. This large degeneracy arises from D0 branes in lowest Landau levels which tile the CY_3xS^2 horizon. It is conjectured that such a multi-D0 brane CFT1 is holographically dual to IIA string theory on AdS_2xS^2xCY_3.Comment: 8 page

Consistency Conditions on S-Matrix of Spin 1 Massless Particles

Motivated by new techniques in the computation of scattering amplitudes of massless particles in four dimensions, like BCFW recursion relations, the question of how much structure of the S-matrix can be determined from purely S-matrix arguments has received new attention. The BCFW recursion relations for massless particles of spin 1 and 2 imply that the whole tree-level S-matrix can be determined in terms of three-particle amplitudes (evaluated at complex momenta). However, the known proofs of the validity of the relations rely on the Lagrangian of the theory, either by using Feynman diagrams explicitly or by studying the effective theory at large complex momenta. This means that a purely S-matrix theoretic proof of the relations is still missing. The aim of this paper is to provide such a proof for spin 1 particles by extending the four-particle test introduced by P. Benincasa and F. Cachazo in arXiv:0705.4305[hep-th] to all particles. We show how n-particle tests imply that the rational function built from the BCFW recursion relations possesses all the correct factorization channels including holomorphic and anti-holomorphic collinear limits. This in turn implies that they give the correct S-matrix of the theory.Comment: 24 pages, 4 figure

A Prestação de Serviços Ambientais pode ser uma alternativa aos sistemas tradicionais da agricultura familiar no município de Pacajá, Amazônia Paraense - Brasil?

Os estabelecimentos familiares, em sua maioria, adotam o sistema tradicional de agricultura, usando a área por um ou dois anos, seguido de pousio. Essa produção, na Amazônia, tem sido identificada, por alguns, como problema social e vilã ecológica. Contraponto a essa visão, compreende-se a agricultura familiar como estratégica na manutenção do emprego, redistribuição da renda, garantia da soberania alimentar do país e a alternativa para o desenvolvimento sustentável, devido à diversificação nos sistemas de produção e características equilibradas na relação homem e natureza. Propõe-se no texto a reflexão sobre Prestação de Serviços Ambientais no município de Pacajá-PA. Adotou-se a ferramenta Eco-Cert. PROAMBIENTE desenvolvida pela Embrapa para identificar as práticas contribuintes com os serviços. Os resultados mostraram que a diversificação é fundamental para prestação de serviços ambientais e as famílias participantes do PROAMBIENTE aumentaram o potencial na prestação de serviços, principalmente por não derrubarem as florestas e reduzirem o uso do fogo

The Cut-Constructible Part of QCD Amplitudes

Unitarity cuts are widely used in analytic computation of loop amplitudes in gauge theories such as QCD. We expand upon the technique introduced in hep-ph/0503132 to carry out any finite unitarity cut integral. This technique naturally separates the contributions of bubble, triangle and box integrals in one-loop amplitudes and is not constrained to any particular helicity configurations. Loop momentum integration is reduced to a sequence of algebraic operations. We discuss the extraction of the residues at higher-order poles. Additionally, we offer concise algebraic formulas for expressing coefficients of three-mass triangle integrals. As an application, we compute all remaining coefficients of bubble and triangle integrals for nonsupersymmetric six-gluon amplitudes.Comment: 78 pages, 3 fig

Avaliação do comportamento produtivo de um rebanho de bubalinos para produção de leite.

Visando explorar não só a capacidade de adaptação do búfalo às condições do trópico úmido, mas também seu considerável potencial leiteiro, foi conduzido no município de Porto Velho, um trabalho baseado num sistema de produção com o objetivo de observar o comportamento produtivo de búfalos mestiços Murrah x Mediterrâneo para a produção de leite a fim de gerar mais uma nova opção em termos de produto nutritivo e de menos custo para o produtor.bitstream/item/56468/1/PA-1147-0001.pd

Single Cut Integration

We present an analytic technique for evaluating single cuts for one-loop integrands, where exactly one propagator is taken to be on shell. Our method extends the double-cut integration formalism of one-loop amplitudes to the single-cut case. We argue that single cuts give meaningful information about amplitudes when taken at the integrand level. We discuss applications to the computation of tadpole coefficients.Comment: v2: corrected typo in abstrac

A Grassmannian Etude in NMHV Minors

Arkani-Hamed, Cachazo, Cheung and Kaplan have proposed a Grassmannian formulation for the S-matrix of N=4 Yang-Mills as an integral over link variables. In parallel work, the connected prescription for computing tree amplitudes in Witten's twistor string theory has also been written in terms of link variables. In this paper we extend the six- and seven-point results of arXiv:0909.0229 and arXiv:0909.0499 by providing a simple analytic proof of the equivalence between the two formulas for all tree-level NMHV superamplitudes. Also we note that a simple deformation of the connected prescription integrand gives directly the ACCK Grassmannian integrand in the limit when the deformation parameters equal zero.Comment: 17 page

Hepta-Cuts of Two-Loop Scattering Amplitudes

We present a method for the computation of hepta-cuts of two loop scattering amplitudes. Four dimensional unitarity cuts are used to factorise the integrand onto the product of six tree-level amplitudes evaluated at complex momentum values. Using Gram matrix constraints we derive a general parameterisation of the integrand which can be computed using polynomial fitting techniques. The resulting expression is further reduced to master integrals using conventional integration by parts methods. We consider both planar and non-planar topologies for 2 to 2 scattering processes and apply the method to compute hepta-cut contributions to gluon-gluon scattering in Yang-Mills theory with adjoint fermions and scalars.Comment: 37 pages, 6 figures. version 2 : minor updates, published versio

Loop amplitudes in gauge theories: modern analytic approaches

This article reviews on-shell methods for analytic computation of loop amplitudes, emphasizing techniques based on unitarity cuts. Unitarity techniques are formulated generally but have been especially useful for calculating one-loop amplitudes in massless theories such as Yang-Mills theory, QCD, and QED.Comment: 34 pages. Invited review for a special issue of Journal of Physics A devoted to "Scattering Amplitudes in Gauge Theories." v2: typesetting macro error fixe