Controlling the group velocity in a five-level K-type atomic system

The properties of a five-level K-type system are investigated. With the controlling fields, the properties of the dispersion and absorption of the system are changed greatly. The system can produce anomalous dispersion regions with absorption and normal dispersion regions with absorption or transparency. Furthermore, the group velocity can be varied from subluminal to superluminal by varying the intensity of the controlling field and the probe detunings in principle. (C) 2008 Elsevier B.V. All rights reserved.

Investigations of group IVA transition metal mediated carbon-carbon bond forming reactions

Zirconocene aldehyde and ketone complexes were synthesized in high yield by treatment of zirconocene acyl complexes with trimethylaluminum or diisobutylaluminum hydride. These complexes, which are activated by dialkylaluminum chloride ligands, inserted unsaturated substrates such as alkynes, allenes, ethylene, nitriles, ketenes, aldehydes, ketones, lactones, and acid chlorides with moderate to high conversion. Insertion of aldehyde substrates yielded zirconocene diolate complexes with up to 20:1 (anti:syn) diastereoselectivity. The zirconocene diolates were hydrolyzed to afford unsymmetrical 1,2-diols in 40-80% isolated yield. Unsymmetrical ketones gave similar insertion yields with little or no diastereoselectivity. A high yielding one-pot method was developed that coupled carbonyl substrates with zirconocene aldehyde complexes that were derived from olefins by hydrozirconation and carbonylation. The zirconocene aldehyde complexes also inserted carbon monoxide and gave acyloins in 50% yield after hydrolysis.

The insertion reaction of aryl epoxides with the trimethylphoshine adduct of titanocene methylidene was examined. The resulting oxytitanacyclopentanes were carbonylated and oxidatively cleaved with dioxygen to afford y-lactones in moderate yields. Due to the instability and difficult isolation of titanocene methylidene trimethylphoshine adducts, a one-pot method involving the addition of catalytic amounts of trimethylphosphine to β,β-dimethyltitanacyclobutane was developed. A series of disubstituted aryl epoxides were examined which gave mixtures of diastereomeric insertion products. Based on these results, as well as earlier Hammett studies and labeling experiments, a biradical transition state intermediate is proposed. The method is limited to aryl substituted epoxide substrates with aliphatic examples showing no insertion reactivity.

The third study involved the use of magnesium chloride supported titanium catalysts for the Lewis acid catalyzed silyl group transfer condensation of enol silanes with aldehydes. The reaction resulted in silylated aldol products with as many as 140 catalytic turnovers before catalyst inactivation. Low diastereoselectivities favoring the anti-isomer were consistent with an open transition state involving a titanium atom bound to the catalyst surface. The catalysts were also used for the aldol group transfer polymerization of t-butyldimethylsilyloxy-1-ethene resulting in polymers with molecular weights of 5000-31,000 and molar mass dispersities of 1.5-2.8. Attempts to polymerize methylmethacrylate using GTP proved unsuccessful with these catalysts.

Information-theoretic Studies and Capacity Bounds: Group Network Codes and Energy Harvesting Communication Systems

Network information theory and channels with memory are two important but difficult frontiers of information theory. In this two-parted dissertation, we study these two areas, each comprising one part. For the first area we study the so-called entropy vectors via finite group theory, and the network codes constructed from finite groups. In particular, we identify the smallest finite group that violates the Ingleton inequality, an inequality respected by all linear network codes, but not satisfied by all entropy vectors. Based on the analysis of this group we generalize it to several families of Ingleton-violating groups, which may be used to design good network codes. Regarding that aspect, we study the network codes constructed with finite groups, and especially show that linear network codes are embedded in the group network codes constructed with these Ingleton-violating families. Furthermore, such codes are strictly more powerful than linear network codes, as they are able to violate the Ingleton inequality while linear network codes cannot. For the second area, we study the impact of memory to the channel capacity through a novel communication system: the energy harvesting channel. Different from traditional communication systems, the transmitter of an energy harvesting channel is powered by an exogenous energy harvesting device and a finite-sized battery. As a consequence, each time the system can only transmit a symbol whose energy consumption is no more than the energy currently available. This new type of power supply introduces an unprecedented input constraint for the channel, which is random, instantaneous, and has memory. Furthermore, naturally, the energy harvesting process is observed causally at the transmitter, but no such information is provided to the receiver. Both of these features pose great challenges for the analysis of the channel capacity. In this work we use techniques from channels with side information, and finite state channels, to obtain lower and upper bounds of the energy harvesting channel. In particular, we study the stationarity and ergodicity conditions of a surrogate channel to compute and optimize the achievable rates for the original channel. In addition, for practical code design of the system we study the pairwise error probabilities of the input sequences.

Death or taxes? The political economy of sanitation expenditure in nineteenth-century Britain

This thesis consists of three papers studying the relationship between democratic reform, expenditure on sanitation public goods and mortality in Britain in the second half of the nineteenth century. During this period decisions over spending on critical public goods such as water supply and sewer systems were made by locally elected town councils, leading to extensive variation in the level of spending across the country. This dissertation uses new historical data to examine the political factors determining that variation, and the consequences for mortality rates.

The first substantive chapter describes the spread of government sanitation expenditure, and analyzes the factors that determined towns' willingness to invest. The results show the importance of towns' financial constraints, both in terms of the available tax base and access to borrowing, in limiting the level of expenditure. This suggests that greater involvement by Westminster could have been very effective in expediting sanitary investment. There is little evidence, however, that democratic reform was an important driver of greater expenditure.

Chapter 3 analyzes the effect of extending voting rights to the poor on government public goods spending. A simple model predicts that the rich and the poor will desire lower levels of public goods expenditure than the middle class, and so extensions of the right to vote to the poor will be associated with lower spending. This prediction is tested using plausibly exogenous variation in the extent of the franchise. The results strongly support the theoretical prediction: expenditure increased following relatively small extensions of the franchise, but fell once more than approximately 50% of the adult male population held the right to vote.

Chapter 4 tests whether the sanitary expenditure was effective in combating the high mortality rates following the Industrial Revolution. The results show that increases in urban expenditure on sanitation-water supply, sewer systems and streets-was extremely effective in reducing mortality from cholera and diarrhea.

A Previdência Social no estado contemporâneo Fundamentos, financiamento e regulação

A previdência social brasileira, apesar de constituir um dos modelos mais antigos e tradicionais de proteção social da América Latina, não muito distante dos modelos europeus quanto a sua gênese, passa por momentos difíceis. Em um contexto de rápido envelhecimento populacional, acelerada redução de natalidade e novas realidades de trabalho, nas quais a mão-de-obra assalariada perde seu espaço, o modelo tradicional de cobertura, nos moldes bismarckianos, carece de revisão, de forma a não somente adequar-se às novas premissas demográficas, mas permitir uma universalidade de cobertura efetiva. Para tanto, adota-se, como fundamento de um novo modelo, a justiça social em três dimensões necessidade, igualdade e mérito. A necessidade visa atender e assegurar a qualquer pessoa, dentro das necessidades sociais cobertas, um pagamento mínimo de forma a assegurar o mínimo existencial. A dimensão da igualdade, no viés material, visa preservar nível de bem-estar compatível, em alguma medida, com o usufruído durante a vida ativa. Já o mérito individual implica fornecer prestações mais elevadas aos que, conscientemente, reduziram o consumo presente, preservando parte de suas receitas para o futuro. As duas primeiras dimensões são, na proposta apresentada, organizadas pelo Estado, em pilares compulsórios e financiados, preponderantemente, por repartição simples. O modelo de financiamento adotado, no longo prazo, tem se mostrado mais seguro e isonômico frente a modelos capitalizados. As variantes demográficas podem ser adequadas mediante novos limites de idade para aposentadorias e, em especial, estímulo a natalidade, como novos serviços da previdência social, incluindo creches e pré-escolas. O terceiro pilar, fundado no mérito individual, é a previdência complementar, organizado de forma privada, autônoma e voluntária. Aqui, o financiamento sugerido é a capitalização, de forma a priorizar o rendimento e a eficiência, com as externalidades positivas para a economia e a sociedade, com risco assumido e aceitável em razão do papel subsidiário deste pilar protetivo. Os pilares estatais, no modelo proposto, serão financiados, exclusivamente, por impostos, pondo-se fim às contribuições sociais, que perdem a importância em um modelo universal de proteção. Troca-se a solidariedade do grupo pela solidariedade social e, como conseqüência, saem as contribuições e ingressam os impostos. Mesmo o segundo pilar, que visa prestações correlacionadas com os rendimentos em atividade, será financiado por adicional de imposto de renda. Sistema mais simples, eficaz, e com estímulo à formalização da receita por parte das pessoas. A gestão do modelo previdenciário, em todos os segmentos, contará com forte regulação estatal, mas com efetiva participação dos interessados, afastadas, dentro do possível, as ingerências políticas e formas de captura. A regulação previdenciária, desde adequadamente disciplinada e executada, permitirá que os pilares propostos funcionem em harmonia.

Práticas do enfermeiro no Programa de HIV/AIDS nos Centros Municipais de Saúde no município do Rio de Janeiro

Trata-se de uma pesquisa de mestrado do Programa de Pós-Graduação da Faculdade de Enfermagem da Universidade do Estado do Rio de Janeiro. Teve como objetivo geral compreender e analisar as práticas do enfermeiro na assistência à saúde no Programa HIV/AIDS nos Centros Municipais de Saúde do Rio de Janeiro a partir do princípio da integralidade. Buscou-se a compreensão da prática do enfermeiro, pois devido à complexidade da epidemia, o paciente requer assistência que estabeleça qualidade de vida. Neste sentido, explorou-se o conceito de integralidade como embasamento para as ações em saúde nos diversos níveis de assistência em especial na atenção básica. O enfermeiro diante de uma perspectiva de integralidade quer no manejo clinico do portador, quer na prevenção da disseminação da doença nos diversos grupos populacionais, deve buscar uma prática profissional com vistas a priorizar as necessidades de saúde dos usuários. Trata-se de um estudo de natureza qualitativa, sendo esta abordagem a que possibilita a compreensão dos fenômenos e das ações humanas no que se refere à prática. A pesquisa foi desenvolvida no período 2008 a 2009, sendo o trabalho de campo desenvolvido através de observação livre e entrevistas semi-estruturadas. Os sujeitos consistiram de 12 enfermeiros que trabalham nos CMS no Programa HIV/AIDS. Os dados foram analisados visando buscar eixos temáticos a fim de transparecer as práticas e seus contextos, utilizando também os registros da observação livre. Através da análise temática emergiram duas categorias: O cotidiano da assistência no programa HIV/AIDS e a Prática do enfermeiro no programa HIV/AIDS, as quais deram origem a cinco subcategorias descritas a seguir: O cotidiano dos CMS e a organização da assistência voltada para o HIV/AIDS; Limitações político-institucionais que dificultam as ações de enfermagem no programa HIV/AIDS; A relação da equipe de saúde e o processo de trabalho no programa HIV/AIDS; Bases teóricas que orientam a prática do enfermeiro em HIV/AIDS nos CMS; e Modelos de atenção à saúde e a realidade vivenciada no programa HIV/AIDS. Podemos constatar que os serviços que atendem HIV/AIDS são estruturados basicamente com a presença dos profissionais de saúde e na estrutura física disponível para a assistência. Este fato influencia a chegada do paciente ao serviço e sua forma de atendimento. Constatou-se que a falta de estrutura física prejudica a percepção das necessidades de saúde do grupo populacional assistido, mas também isto nos remete a falta de preparo do profissional. Há muita dificuldade em articular o conhecimento teórico com a prática diária, isto é, com suas atividades de rotina. Neste caso, o enfermeiro busca, a partir das ações que são postas no dia-a-dia, superar essa indefinição na tentativa de dar respostas aos problemas de saúde que lhes são direcionados. Concluímos que há necessidade de condições mais específicas para o desenvolvimento de ações que possibilitem a visualização das necessidades de saúde desta clientela para que possa desenvolver a integralidade de forma consistente nos CMS do Rio de Janeiro.

The effect of the group delay ripple of chirped fiber grating on composite second-order in optical fiber CATV system

The effect of group delay ripple of chirped fiber gratings on composite second-order (CSO) performance in optical fiber CATV system is investigated. We analyze the system CSO performances for different ripple amplitudes, periods and residual dispersion amounts in detail. It is found that the large ripple amplitude and small ripple period will deteriorate the system CSO performance seriously. Additionally, the residual dispersion amount has considerable effect on CSO performance in the case of small ripple amplitude and large ripple period. (c) 2004 Elsevier B.V. All rights reserved.

Two topics in elementary particle physics. I. Crossing as a group and elimination of exotic channels. II. Real parts of meson-nucleon forward scattering amplitudes.

I. Crossing transformations constitute a group of permutations under which the scattering amplitude is invariant. Using Mandelstem's analyticity, we decompose the amplitude into irreducible representations of this group. The usual quantum numbers, such as isospin or SU(3), are "crossing-invariant". Thus no higher symmetry is generated by crossing itself. However, elimination of certain quantum numbers in intermediate states is not crossing-invariant, and higher symmetries have to be introduced to make it possible. The current literature on exchange degeneracy is a manifestation of this statement. To exemplify application of our analysis, we show how, starting with SU(3) invariance, one can use crossing and the absence of exotic channels to derive the quark-model picture of the tensor nonet. No detailed dynamical input is used.

II. A dispersion relation calculation of the real parts of forward π^±p and K^±p scattering amplitudes is carried out under the assumption of constant total cross sections in the Serpukhov energy range. Comparison with existing experimental results as well as predictions for future high energy experiments are presented and discussed. Electromagnetic effects are found to be too small to account for the expected difference between the π^-p and π⁺p total cross sections at higher energies.

Ecological effects of trial pumpings in the Upper Lambourn: Stage 1 group pumping test Upper Lambourn group, September - November 1975

This report to the Thames Water Authority and Central Water Planning Unit is on research carried out in conjunction with the Stage 1 Group Pumping Test of five boreholes in the upper Lambourn Group for a period of three months in September, October and November 1975. The aim of the study was to assess the ecological effects of the pumpin g of five bore-holes in the upper Lambourn. That is, to determine how the seasonal sequence of ecological events in the river differed from what would hav e occurred had no pumping taken place. Since this 'experiment' has no control it is not possible to make a direct assessment. Nevertheless, by careful monitoring of ecological events before, during and after the pumping it is possible to document changes in th e river and by reference to the data already available for the Rive r Lambourn, normal seasonal changes in the flora and fauna can be separated from changes which may be attributable to the pumping and subsequent events.

Heteroepitaxy of Group IV and Group III-V semiconductor alloys for photovoltaic applications

Photovoltaic energy conversion represents a economically viable technology for realizing collection of the largest energy resource known to the Earth -- the sun. Energy conversion efficiency is the most leveraging factor in the price of energy derived from this process. This thesis focuses on two routes for high efficiency, low cost devices: first, to use Group IV semiconductor alloy wire array bottom cells and epitaxially grown Group III-V compound semiconductor alloy top cells in a tandem configuration, and second, GaP growth on planar Si for heterojunction and tandem cell applications.

Metal catalyzed vapor-liquid-solid grown microwire arrays are an intriguing alternative for wafer-free Si and SiGe materials which can be removed as flexible membranes. Selected area Cu-catalyzed vapor-liquid solid growth of SiGe microwires is achieved using chlorosilane and chlorogermane precursors. The composition can be tuned up to 12% Ge with a simultaneous decrease in the growth rate from 7 to 1 μm/min^-1. Significant changes to the morphology were observed, including tapering and faceting on the sidewalls and along the lengths of the wires. Characterization of axial and radial cross sections with transmission electron microscopy revealed no evidence of defects at facet corners and edges, and the tapering is shown to be due to in-situ removal of catalyst material during growth. X-ray diffraction and transmission electron microscopy reveal a Ge-rich crystal at the tip of the wires, strongly suggesting that the Ge incorporation is limited by the crystallization rate.

Tandem Ga_1-xIn_xP/Si microwire array solar cells are a route towards a high efficiency, low cost, flexible, wafer-free solar technology. Realizing tandem Group III-V compound semiconductor/Si wire array devices requires optimization of materials growth and device performance. GaP and Ga_1-xIn_xP layers were grown heteroepitaxially with metalorganic chemical vapor deposition on Si microwire array substrates. The layer morphology and crystalline quality have been studied with scanning electron microscopy and transmission electron microscopy, and they provide a baseline for the growth and characterization of a full device stack. Ultimately, the complexity of the substrates and the prevalence of defects resulted in material without detectable photoluminescence, unsuitable for optoelectronic applications.

Coupled full-field optical and device physics simulations of a Ga_0.51In_0.49P/Si wire array tandem are used to predict device performance. A 500 nm thick, highly doped "buffer" layer between the bottom cell and tunnel junction is assumed to harbor a high density of lattice mismatch and heteroepitaxial defects. Under simulated AM1.5G illumination, the device structure explored in this work has a simulated efficiency of 23.84% with realistic top cell SRH lifetimes and surface recombination velocities. The relative insensitivity to surface recombination is likely due to optical generation further away from the free surfaces and interfaces of the device structure.

Finally, GaP has been grown free of antiphase domains on Si (112) oriented substrates using metalorganic chemical vapor deposition. Low temperature pulsed nucleation is followed by high temperature continuous growth, yielding smooth, specular thin films. Atomic force microscopy topography mapping showed very smooth surfaces (4-6 Å RMS roughness) with small depressions in the surface. Thin films (~ 50 nm) were pseudomorphic, as confirmed by high resolution x-ray diffraction reciprocal space mapping, and 200 nm thick films showed full relaxation. Transmission electron microscopy showed no evidence of antiphase domain formation, but there is a population of microtwin and stacking fault defects.

O papel dos grupos de interesse no "trade policy making" brasileiro: o caso das negociações Brasil-Argentina para o setor automotivo

Desde a redemocratização do país em 1985 o MRE já vinha se posicionando à favor do diálogo com os mais diversos grupos e entidades sociais. Neste sentido, observou-se ao longo dos últimos anos um aprofundamento da interação com parlamentares, governos estaduais e municipais, empresários, sindicalistas, ONGs e imprensa. A construção de vínculos entre as organizações da sociedade civil críticas das negociações comerciais ao longo da década de 1990 permite falar na criação de um novo campo de ação coletiva transnacional, definido como um espaço de ação política formado por indivíduos e organizações da sociedade civil que participam do processo de elaboração de um conjunto comum de práticas, objetivos e crenças. O que se pode concluir é que diante de um contexto mais competitivo e globalizado, após processo de abertura comercial e intensificação da participação brasileira nas negociações internacionais, a representação dos interesses da classe empresarial teve que se adaptar criando uma nova forma de organização. Desse modo, o presente trabalho visa analisar a crescente interferência de grupos de interesse no processo de tomada de decisão, no que tange aos assuntos de política externa comercial brasileira, tais como as negociações comerciais internacionais por se tratar de um ambiente cujos interesses da classe empresarial mais podem ser afetados. As negociações comerciais internacionais é o ambiente em que a atuação empresarial mais pode ser percebida. As negociações do Mercosul e da ALCA possibilitam observar a participação ativa destes novos atores. Sendo assim, o trabalho apresenta a nova dinâmica de relacionamento entre Estado e grupos da sociedade civil (classe empresarial) para temas ligados a comércio exterior.

From social to political. New forms of mobilization and democratization. Conference proceedings

In the recent evolution of contemporary social movements three phases can be identified. The first phase is marked by the labour movement and the systemic importance attributed to the labour conflict in industrial societies. This conflict has been interpreted as a consequence of the shortcoming of social integration mechanisms by Emile Durkheim, as a rational conflict by entrepreneurs’ and workers’ interests by Max Wener, and as a central class struggle for the transformation of society by Karl Marx. The second phase in this development was led by the new social movements of the post-industrial society of the 1960s and 1970s’ students, women and environmentalist movements. Two new analytical perspectives have explained these movements’ meaning and actions. Resource mobilization theory (McAdam and Tilly) has focuses on rational attitudes and conflicts. Actionalist sociology, in turn, has identified the new protagonists of social conflicts that replaced the labour movement in postindustrial societies. The third phase emerges in a world characterized by the ascendance of markets, the increasingly prominent role of financial capital flows, the closure of communities, and fundamentalism. In this context, human rights and pro-democratization movements constitute alternatives to global domination and the systemic conditioning of individual and groups.

A vulnerabilidade da vida com HIV/AIDS

Esta tese pretende contribuir para o desenvolvimento de respostas públicas rumo à diminuição do impacto do HIV/Aids nos campos, econômico, político e social tanto no nível coletivo quanto no individual. Discute aspectos téorico-conceituais das noções de risco e vulnerabilidade, mostrando que a atual aplicação e apropriação dessas noções na resposta à essa epidemia dificulta o reconhecimento dos problemas adicionais enfrentados após o diagnóstico. Apresenta as diversas formas de pobreza, desigualdade e exclusão a partir dos indicadores sociais comumente usados e respectivas lógicas construtivas. Questiona as afirmações recentes sobre a queda da desigualdade, da pobreza e da indigência no país; e considera que a desigualdade e a exclusão que afetam a população em geral é a mesma a afetar pessoas que vivem com HIV/Aids. Porém, aponta a existência de vulnerabilidade potencial, conceito desenvolvido nesta tese, na ausência de rede de suporte social. Para identificar e inferir sobre o que ocorre nas vidas das pessoas que vivem em situação de desigualdade ou exclusão após a infecção pelo HIV utiliza dados coletados em pesquisa de survey, discursos, estórias e memórias de casos reais da prática profissional desta autora. O objetivo desta tese é demonstrar que o conceito de vulnerabilidade aplicado após o diagnóstico é importante ferramenta para reconhecer e intervir sobre as dificuldades e problemas adicionais enfrentados. Ressalta a evolução da resposta brasileira à essa epidemia e demonstra as lacunas existentes como desafios a seu aperfeiçoamento. Conclui que o reconhecimento dos problemas adicionais após o diagnóstico e o uso do conceito de vulnerabilidade potencial abre novas possibilidades de enfrentamento do HIV/Aids e exige respostas públicas interligadas e intersetoriais.