Integral equations of scattering in one dimension

A self-contained discussion of integral equations of scattering is presented in the case of centrally-symmetric potentials in one dimension, which will facilitate the understanding of more complex scattering integral equations in two and three dimensions. The present discussion illustrates in a simple fashion the concept of partial-wave decomposition, Green's function, Lippmann-Schwinger integral equations of scattering for wave function and transition operator, optical theorem and unitarity relation. We illustrate the present approach with a Dirac delta potential.Comment: 12 pages, accepted in American Journal of Physic

Topological Dilatonic Supergravity Theories

We present a central extension of the $(m,n)$ super-Poincar\'e algebra in two dimensions. Besides the usual Poincar\'e generators and the $(m,n)$ supersymmetry generators we have $(m,n)$ Grassmann generators, a bosonic internal symmetry generator and a central charge. We then build up the topological gauge theory associated to this algebra. We can solve the classical field equations for the fields which do not belong to the supergravity multiplet and to a Lagrange multiplier multiplet. The resulting topological supergravity theory turns out to be non-local in the fermionic sector.Comment: 11 pages, plain TeX, IFUSP-P/112

Estudo comparativo dos ambientes para ensino a distância Web Course Tools e AulaNet.

Este trabalho apresenta um levantamento das caracterrsticas e um estudo comparativo entre dois ambientes de autoria e aplicação de cursos a distância presentes no mercado. Para este estudo foram utilizados os ambientes Web Course Tools WebCT, versão 30, desenvolvido pela Universidade de Columbia, no Canadá, e o AulaNet, versão 1 .2, desenvolvido pela Pontifícia Universidade Católica do Rio de Janeiro.bitstream/item/76663/1/CNPTIA-COM.TEC.-9-00.pd

Procedimentos para elaboração de um curso a distância.

Exemplo de um ambiente de curso a distância. Descrição do procedimento para elaboração de um curso a distância: Estabelecimento de contato com os clientes que estão requisitando o curso a distância. Identificação de requisitos gerais, requisitos funcionais e requisitos computacionais. Preparação do material do curso para WWW. Implantação do curso.bitstream/CNPTIA/9214/1/DOCUMENTO6int.pdfAcesso em: 29 maio 2008

Seleccion de especies y procedencias del genero Eucalyptus para la region costera de Bahia, Brasil.

Con el objetivo de evaluar y seleccionar las mejores especies y/o procedencias de Eucalyptus para la region costera del Estado de Bahia (Brasil), el presente trabajo fue establecido en la Hacienda Buri, de la empresa Reflora/Ferbasa, provincia de Pojuca, Estado de Bahia, ubicada entre las coordenadas 12ø2S~51"Lat. S y 38ø19~40"Long. W, con altitud respecto al nivel del mar de 55 m. La precipitacion media anual es de 1.200 mm, concentrada entre los meses de abril y julio, con temperatura media de 25øC. Los suelos son acidos y de baja fertilidad natural. Los plantones fueron producidos en vivero de la Ernbrapa Semi-Arido, en Petrolina-PE, y conducidos al campo con altura media de 25 cm y plantados con espaciado de 3,0 m x 1,33 m, sin abono de fundacion. Fueron testadas cinco procedencias de E. urophylla, cuatro de E. camaldulensis, tres de E. brassiana y E. pellita, dos de E. citriodora, E. grandis y E. tereticornis y una de E. drepanophylla. Ei diseflo estadistico fue el de bloques al azar, con parcelas en lineas de cinco plantas, con diez repeticiones. En la evaluacion a los 30 dias del plantio, fue observado 100% de supervivencia en todas las especies y buen desempeflo silvicultural sin problemas fitosanitarios. A los 8 meses de edad los resultados apuntan variaciones significativas para la altura y supervivencia. Las especies/procedencias de mayor desarrollo en la region de Pojuca-BA, fueron E. urophylla, Proc. 14540, E. tereticornis Proc. CPATSA, E. grandis Proc. Rio Claro-SP, E. camaldulensis Proc. 14517, con alturas de 3,94; 3,64; 3,51; 3,46 y 3,45 m respectivamente, y estadisticamente superiores a las demas, con supervivencia por encima de 83%

Critical exponents from parallel plate geometries subject to periodic and antiperiodic boundary conditions

We introduce a renormalized 1PI vertex part scalar field theory setting in momentum space to computing the critical exponents $\nu$ and $\eta$, at least at two-loop order, for a layered parallel plate geometry separated by a distance L, with periodic as well as antiperiodic boundary conditions on the plates. We utilize massive and massless fields in order to extract the exponents in independent ultraviolet and infrared scaling analysis, respectively, which are required in a complete description of the scaling regions for finite size systems. We prove that fixed points and other critical amounts either in the ultraviolet or in the infrared regime dependent on the plates boundary condition are a general feature of normalization conditions. We introduce a new description of typical crossover regimes occurring in finite size systems. Avoiding these crossovers, the three regions of finite size scaling present for each of these boundary conditions are shown to be indistinguishable in the results of the exponents in periodic and antiperiodic conditions, which coincide with those from the (bulk) infinite system.Comment: Modified introduction and some references; new crossover regimes discussion improved; Appendixes expanded. 48 pages, no figure

Anisotropic Lifshitz Point at O(ϵL2)O(\epsilon_L^2)

We present the critical exponents $\nu_{L2}$, $\eta_{L2}$ and $\gamma_{L}$ for an $m$-axial Lifshitz point at second order in an $\epsilon_{L}$ expansion. We introduced a constraint involving the loop momenta along the $m$-dimensional subspace in order to perform two- and three-loop integrals. The results are valid in the range $0 \leq m < d$. The case $m=0$ corresponds to the usual Ising-like critical behavior.Comment: 10 pages, Revte