Mass Generation from Lie Algebra Extensions

Applied to the electroweak interactions, the theory of Lie algebra extensions suggests a mechanism by which the boson masses are generated without resource to spontaneous symmetry breaking. It starts from a gauge theory without any additional scalar field. All the couplings predicted by the Weinberg-Salam theory are present, and a few others which are nevertheless consistent within the model.Comment: 11 pages; revtex; title and PACS have been changed; comments included in the manuscrip

Cana-do-brejo.

Cana-do-brejo (Costus spicatus Jacq.), também conhecida como cana-de-macaco, cana-do-mansa, caatinga, cana-branca, cana-do-mato, é nativa em quase todo o Brasil, principalmente em áreas de Mata Atlântica e Amazônica, onde é tradicionalmente utilizada como medicinal e ornamental, devido a sua ação diurética e beleza.bitstream/item/51600/1/f-01.pd

Gravitation and Duality Symmetry

By generalizing the Hodge dual operator to the case of soldered bundles, and working in the context of the teleparallel equivalent of general relativity, an analysis of the duality symmetry in gravitation is performed. Although the basic conclusion is that, at least in the general case, gravitation is not dual symmetric, there is a particular theory in which this symmetry shows up. It is a self dual (or anti-self dual) teleparallel gravity in which, due to the fact that it does not contribute to the interaction of fermions with gravitation, the purely tensor part of torsion is assumed to vanish. The ensuing fermionic gravitational interaction is found to be chiral. Since duality is intimately related to renormalizability, this theory may eventually be more amenable to renormalization than teleparallel gravity or general relativity.Comment: 7 pages, no figures. Version 2: minor presentation changes, references added. Accepted for publication in Int. J. Mod. Phys.

Primordial magnetic fields constrained by CMB anisotropies and dynamo cosmology

Magneto-curvature stresses could deform magnetic field lines and this would give rise to back reaction and restoring magnetic stresses [Tsagas, PRL (2001)]. Barrow et al [PRD (2008)] have shown in Friedman universe the expansion to be slow down in spatial section of negative Riemann curvatures. From Chicone et al [CMP (1997)] paper, proved that fast dynamos in compact 2D manifold implies negatively constant Riemannian curvature, here one applies the Barrow-Tsagas ideas to cosmic dynamos. Fast dynamo covariant stretching of Riemann slices of cosmic Lobachevsky plane is given. Inclusion of advection term on dynamo equations [Clarkson et al, MNRAS (2005)] is considered. In absence of advection a fast dynamo is also obtained. Viscous and restoring forces on stretching particles decrease, as magnetic rates increase. From COBE data ($\frac{{\delta}B}{B}\approx{10^{-5}}$), one computes stretching $\frac{{\delta}V^{y}}{V^{y}}=1.5\frac{{\delta}B}{B}\approx{1.5{\times}10^{-5}}$. Zeldovich et al has computed the maximum magnetic growth rate as ${\gamma}_{max}\approx{8.0{\times}10^{-1}t^{-1}}$. From COBE data one computes a lower growth rate for the magnetic field as ${\gamma}_{COBE}\approx{6.0{\times}10^{-6}t^{-1}}$, well-within Zeldovich et al estimate. Instead of the Harrison value $B\approx{t^{{4/3}}}$ one obtains the lower primordial field $B\approx{10^{-6}t}$ which yields the $B\approx{10^{-6}G}$ at the $1s$ Big Bang time.Comment: Dept of theoretical physics-UERJ-Brasi

SPRINKMOD - Simulation of pressure and discharge distributions in pressurized irrigation systems: graphical interface and strategy of design.

SPRINKMOD is a computer model that simulates pressure and flow rate distributions along pipes and laterals of pressurized irrigation systems. The software runs in a WINDOWS environment and simulates irrigation systems having multiple pump stations combined in series and/or in parallel, booster pump stations, parallel pipes and looping pipes in addition to more traditional, branched pressurized irrigation systems. Lateral types include hand-move, wheel line and center pivot lateral that may utilize pressure regulators and booster pumps. Leakage is included in the main pipe network and along the laterals and effects of plugged or worn nozzles are accounted for. Pratically any type of nozzle and pump can be simulated since cubic spline functions are used to interpolate values from head-flow rate sets of data. Algorithms were developed and adapted to convert laterals into a single set of head-flow rate data so that a simplified algorithm can be used to solve the entire pipe network. A user-friendly interface is used to allow data for pumps, nozzle and pressure regulators to be interactively entered, edited and analyzed. The layout of the irrigation system is drawn on screen using the mouse

Oferta e comercializacao de melancia na CEASA-PI(1991-1996).

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PUMPCOM: um modelo para combinação de curvas e análise do desempenho de bombas.

Um modelo de computador foi desenvolvido para combinar curvas de bombas em serie e em paralelo e para determinar o desempenho da estacao de bombeamento e da bombas que a compõem. Polinomios sao ajustados aos dados das curvas da cada bomba e aos dados combinados da estacao de bombeamento. A interpolacao "spline" cubica e utilizada para combinar curvas de bomba de capacidade diferente. Indicadores de desempenho da estacao e de cada bomba, individualmente, sao calculados para toda a faixa de vazao de operacao do sistema. Uma interface grafica permite ao usuario desenhar o croqui da estacao de bombeamento e visualizar os dados de cada bomba e as equacoes ajustadas. Dados, graficos e coeficiente de equacoes ajustadas podem ser impressos. Os calculos do modelo foram verificados com planilha eletronica