Structure of potentials with NN Higgs doublets

Extensions of the Standard Model with $N$ Higgs doublets are simple extensions presenting a rich mathematical structure. An underlying Minkowski structure emerges from the study of both variable space and parameter space. The former can be completely parametrized in terms of two future lightlike Minkowski vectors with spatial parts forming an angle whose cosine is $-(N-1)^{-1}$. For the parameter space, the Minkowski parametrization enables one to impose sufficient conditions for bounded below potentials, characterize certain classes of local minima and distinguish charge breaking vacua from neutral vacua. A particular class of neutral minima presents a degenerate mass spectrum for the physical charged Higgs bosons.Comment: 11 pages. Revtex4. Typos corrected. Few comments adde

A computationally efficient method for calculating the maximum conductance of disordered networks: Application to 1-dimensional conductors

Random networks of carbon nanotubes and metallic nanowires have shown to be very useful in the production of transparent, conducting films. The electronic transport on the film depends considerably on the network properties, and on the inter-wire coupling. Here we present a simple, computationally efficient method for the calculation of conductance on random nanostructured networks. The method is implemented on metallic nanowire networks, which are described within a single-orbital tight binding Hamiltonian, and the conductance is calculated with the Kubo formula. We show how the network conductance depends on the average number of connections per wire, and on the number of wires connected to the electrodes. We also show the effect of the inter-/intra-wire hopping ratio on the conductance through the network. Furthermore, we argue that this type of calculation is easily extendable to account for the upper conductivity of realistic films spanned by tunneling networks. When compared to experimental measurements, this quantity provides a clear indication of how much room is available for improving the film conductivity.Comment: 7 pages, 5 figure

Hysteresis and re-entrant melting of a self-organized system of classical particles confined in a parabolic trap

A self-organized system composed of classical particles confined in a two-dimensional parabolic trap and interacting through a potential with a short-range attractive part and long-range repulsive part is studied as function of temperature. The influence of the competition between the short-range attractive part of the inter-particle potential and its long-range repulsive part on the melting temperature is studied. Different behaviors of the melting temperature are found depending on the screening length ($\kappa$) and the strength ($B$) of the attractive part of the inter-particle potential. A re-entrant behavior and a thermal induced phase transition is observed in a small region of ($\kappa,B$)-space. A structural hysteresis effect is observed as a function of temperature and physically understood as due to the presence of a potential barrier between different configurations of the system.Comment: 8 pages, 6 figure

Variabilidade genética entre diploides de banana quanto ao despencamento dos frutos.

O despencamento natural dos frutos maduros é um dos graves problemas dos programas de melhoramento genético de bananeira relacionado a qualidade do fruto. O desprendimento individual dos frutos é uma desordem fisiológica associada ao amadurecimento (1), que resulta em alta perecibilidade pós-colheita

Manual do Sistema Balanço Hídrico e Calendário Agrícola.

Manual do Sistema Balanço Hídrico; Explicação e observações sobre os termos empregados nas tabelas do Balanço Hídrico; Modelo Entidade Relacionamento (MER); Objetivo operacional do sistema; Diferenciamento das duas maneiras de processamento do sistema; Funcionamento; Módulo arquivos; Módulo Balanço Hídrico; Módulo Utilitário; Módulo Sobre.bitstream/item/116808/1/834.pd

Simulation of VUV electroluminescence in micropattern gaseous detectors: the case of GEM and MHSP

Electroluminescence produced during avalanche development in gaseous avalanche detectors is an useful information for triggering, calorimetry and tracking in gaseous detectors. Noble gases present high electroluminescence yields, emitting mainly in the VUV region. The photons can provide signal readout if appropriate photosensors are used. Micropattern gaseous detectors are good candidates for signal amplification in high background and/or low rate experiments due to their high electroluminescence yields and radiopurity. In this work, the VUV light responses of the Gas Electron Multiplier and of the Micro-Hole Strip Plate, working with pure xenon, are simulated and studied in detail using a new and versatile C++ toolkit. It is shown that the solid angle subtended by a photosensor placed below the microstructures depends on the operating conditions. The obtained absolute EL yields, determined for different gas pressures and as functions of the applied voltage, are compared with those determined experimentally.Comment: Accepted for publication in Journal of Instrumentatio

Avaliação de quatro alternativas de análise de experimentos em látice quadrado, quanto a estimação de componentes de variância.

Estudou-se, no presente trabalho, a eficiencia das seguintes alternativas de analise de experimentos realizados em latice quanto a precisao na estimacao de componentes de variancia, atraves da simulacao computacional de dados. i) analise intrablocos do latice com tratamentos ajustados (primeira analise); ii) analise de latice em blocos casualizados completos (segunda analise); iii) analise intrablocos do latice com tratamentos nao-ajustados (terceira analise); iv) analise do latice como blocos casualizados completos, utilizando as medias ajustadas dos tratamentos, obtidos a partir da analise com recuperacao da informacao interblocos, tendo como quadrado medio do residuo a variancia efetiva media dessa analise do latice (quatro analise). Os resultados obtidos mostram que se deve utilizar o modelo de analise intra blocos de experimentos em latos para se estimar em componentes de variancia sempre que a eficiencia relativa do delineamento em latice, em relacao ao delineamento em Blocos Completos Casualizados, for superior a 100% e, em caso contrario, deve-se optar pelo modelo de analise em Blocos Casualizados Completos. A quarta alternativa de analise nao deve ser recomendada em qualquer das duas situacoes