Test particle motion in a Lorentz gas

This is a two-part thesis concerning the motion of a test particle in a bath. In part one we use an expansion of the operator PLe^it(1-P)LLP to shape the Zwanzig equation into a generalized Fokker-Planck equation which involves a diffusion tensor depending on the test particle's momentum and the time.

In part two the resultant equation is studied in some detail for the case of test particle motion in a weakly coupled Lorentz Gas. The diffusion tensor for this system is considered. Some of its properties are calculated; it is computed explicitly for the case of a Gaussian potential of interaction.

The equation for the test particle distribution function can be put into the form of an inhomogeneous Schroedinger equation. The term corresponding to the potential energy in the Schroedinger equation is considered. Its structure is studied, and some of its simplest features are used to find the Green's function in the limiting situations of low density and long time.

The Voting Rights Act, Shelby County, and Redistricting: Improving Estimates of Racially Polarized Voting in a Multiple-Election Context

The Supreme Court’s decision in Shelby County has severely limited the power of the Voting Rights Act. I argue that Congressional attempts to pass a new coverage formula are unlikely to gain the necessary Republican support. Instead, I propose a new strategy that takes a “carrot and stick” approach. As the stick, I suggest amending Section 3 to eliminate the need to prove that discrimination was intentional. For the carrot, I envision a competitive grant program similar to the highly successful Race to the Top education grants. I argue that this plan could pass the currently divided Congress.

Without Congressional action, Section 2 is more important than ever before. A successful Section 2 suit requires evidence that voting in the jurisdiction is racially polarized. Accurately and objectively assessing the level of polarization has been and continues to be a challenge for experts. Existing ecological inference methods require estimating polarization levels in individual elections. This is a problem because the Courts want to see a history of polarization across elections.

I propose a new 2-step method to estimate racially polarized voting in a multi-election context. The procedure builds upon the Rosen, Jiang, King, and Tanner (2001) multinomial-Dirichlet model. After obtaining election-specific estimates, I suggest regressing those results on election-specific variables, namely candidate quality, incumbency, and ethnicity of the minority candidate of choice. This allows researchers to estimate the baseline level of support for candidates of choice and test whether the ethnicity of the candidates affected how voters cast their ballots.

Value Estimation and Comparison in Multi-Attribute Choice

The following work explores the processes individuals utilize when making multi-attribute choices. With the exception of extremely simple or familiar choices, most decisions we face can be classified as multi-attribute choices. In order to evaluate and make choices in such an environment, we must be able to estimate and weight the particular attributes of an option. Hence, better understanding the mechanisms involved in this process is an important step for economists and psychologists. For example, when choosing between two meals that differ in taste and nutrition, what are the mechanisms that allow us to estimate and then weight attributes when constructing value? Furthermore, how can these mechanisms be influenced by variables such as attention or common physiological states, like hunger?

In order to investigate these and similar questions, we use a combination of choice and attentional data, where the attentional data was collected by recording eye movements as individuals made decisions. Chapter 1 designs and tests a neuroeconomic model of multi-attribute choice that makes predictions about choices, response time, and how these variables are correlated with attention. Chapter 2 applies the ideas in this model to intertemporal decision-making, and finds that attention causally affects discount rates. Chapter 3 explores how hunger, a common physiological state, alters the mechanisms we utilize as we make simple decisions about foods.

Determination of the activity of nitrifying bacteria in surface waters by a modified BOD-test. [Translation from: Zentbl.Bakt.Parasitkde 156(1) 414-421, 1972. ]

A modified method of the Biochemical oxygen demand (BOD)test was applied in order to find out the seasonal changing activity of the nitrifying bacteria in surface waters. Samples were taken from the River Elbe near Teufelsbrueck.

Programming chemical kinetics: engineering dynamic reaction networks with DNA strand displacement

Over the last century, the silicon revolution has enabled us to build faster, smaller and more sophisticated computers. Today, these computers control phones, cars, satellites, assembly lines, and other electromechanical devices. Just as electrical wiring controls electromechanical devices, living organisms employ "chemical wiring" to make decisions about their environment and control physical processes. Currently, the big difference between these two substrates is that while we have the abstractions, design principles, verification and fabrication techniques in place for programming with silicon, we have no comparable understanding or expertise for programming chemistry.

In this thesis we take a small step towards the goal of learning how to systematically engineer prescribed non-equilibrium dynamical behaviors in chemical systems. We use the formalism of chemical reaction networks (CRNs), combined with mass-action kinetics, as our programming language for specifying dynamical behaviors. Leveraging the tools of nucleic acid nanotechnology (introduced in Chapter 1), we employ synthetic DNA molecules as our molecular architecture and toehold-mediated DNA strand displacement as our reaction primitive.

Abstraction, modular design and systematic fabrication can work only with well-understood and quantitatively characterized tools. Therefore, we embark on a detailed study of the "device physics" of DNA strand displacement (Chapter 2). We present a unified view of strand displacement biophysics and kinetics by studying the process at multiple levels of detail, using an intuitive model of a random walk on a 1-dimensional energy landscape, a secondary structure kinetics model with single base-pair steps, and a coarse-grained molecular model that incorporates three-dimensional geometric and steric effects. Further, we experimentally investigate the thermodynamics of three-way branch migration. Our findings are consistent with previously measured or inferred rates for hybridization, fraying, and branch migration, and provide a biophysical explanation of strand displacement kinetics. Our work paves the way for accurate modeling of strand displacement cascades, which would facilitate the simulation and construction of more complex molecular systems.

In Chapters 3 and 4, we identify and overcome the crucial experimental challenges involved in using our general DNA-based technology for engineering dynamical behaviors in the test tube. In this process, we identify important design rules that inform our choice of molecular motifs and our algorithms for designing and verifying DNA sequences for our molecular implementation. We also develop flexible molecular strategies for "tuning" our reaction rates and stoichiometries in order to compensate for unavoidable non-idealities in the molecular implementation, such as imperfectly synthesized molecules and spurious "leak" pathways that compete with desired pathways.

We successfully implement three distinct autocatalytic reactions, which we then combine into a de novo chemical oscillator. Unlike biological networks, which use sophisticated evolved molecules (like proteins) to realize such behavior, our test tube realization is the first to demonstrate that Watson-Crick base pairing interactions alone suffice for oscillatory dynamics. Since our design pipeline is general and applicable to any CRN, our experimental demonstration of a de novo chemical oscillator could enable the systematic construction of CRNs with other dynamic behaviors.

Razões, sentimentos e projetos profissionais: experiência dos vestibulandosas (Vitória, ES, 2009 - 2010)

Dar nitidez aos sentimentos e razões que emergem das experiências dos vestibulandos de Vitória-ES, entre 2009-2010, e que os movem em direção a seus projetos profissionais é objetivo deste trabalho. A noção de projeto aqui utilizada (VELHO, 1999) afasta-se da clássica compreensão liberal do ser humano, autônomo, livre e único, responsável por seus sucessos e fracassos, subjacente a estudos sobre escolha profissional. A ideia proposta é que campo de experiências dos sujeitos marca seus projetos profissionais, mas que suas condutas deliberadas, não necessariamente racionais, expõem certas expectativas de vida, quaisquer que sejam as posições sociais desses sujeitos. Para o exame dessas expectativas, esses sujeitos foram vistos em suas relações sociais - nas interseções de classes, gênero, de cor da pele, de gerações, etc. Reconheceu-se, ainda, que razões e sentimentos (WILLIAMS, 1969), também forjam projetos profissionais de sujeitos sob diversas condições sociais e apesar delas. Por considerar que esses projetos portam manifestações humanas, nem sempre perceptíveis e tantas vezes encobertas, a metáfora do rizoma (DELEUZE; GUATTARI, 2004), foi de utilidade metodológica. Alguns indícios (GINZBURG, 2007), sugeriram caminhos de pesquisa e alguns dos significados aos sujeitos para que esses projetos pudessem ser detectados. A perspectiva da longa duração histórica e dos tempos múltiplos presidiu o exame de trajetórias selecionadas de um conjunto de sujeitos pesquisados entre os anos 2009-2010, o que favoreceu a percepção de continuidades históricas, mas também a ocorrência de mudanças de certas tendências sociais. Dois cursos de pré-vestibular, um público e um privado, em Vitória, ES, nessa conjuntura, mostraram um pouco da pluralidade de expectativas de diferentes jovens - pobres, de classes média e alta, homens e mulheres, brancos, negros e pardos, mais novos e mais velhos em relação ao ensino superior presente em seus projetos profissionais. Razões e sentimentos que os movem e que se movem, nem sempre examinados em estudos sobre a matéria, foram expostos. Contribuições de Elias (1990), de R. Williams (1969), de Bourdieu (2003, 2009), de E. P. Thompson (2002), de Löwy (1990), entre outros, apoiaram evidências de que as relações indivíduo e sociedade, sempre plurais e complexas, expressam apenas partes de seus sentidos civilizadores. Para reduzir incertezas, recorreu-se a dados macrossociais e microssociais (REVEL, 1998). Entrevistas com tais jovens e coordenadores de seus cursos, observações advindas de dinâmica de grupo e, também, exame de publicações oficiais, de periódicos de divulgação de matéria sobre vestibular, entre 2009-2010, situaram um trato de escalas analíticas de difícil exercício. Para além das relações de classes, gênero, cor da pele, geração etc., pode-se concluir que esses sujeitos, por razões e sentimentos variados, com seus projetos profissionais, tanto se deslocam de suas posições sociais de origem como as mantêm, mas todos, em suas novas experiências e de diferentes modos, também se preparam para atuar sobre os sentidos civilizadores de seu tempo.

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.

Progress report on fish counting on the Rivers Itchen and Test

This progress report summarises work on NSHEB Mark 10 fish counters which are installed at Woodmill on the River Itchen and Nurseling Mill and Connegar Bridge on the River Test. Counters are evaluated and salmon behaviour regarding the counters examined. The report includes a a list of equipment needed for the efficient running of the project in the future.

A Poética de Adélia Prado: espaço de articulação entre língua portuguesa e língua literária

A tese estuda a obra poética de Adélia Prado sob o ponto de vista da Estilística. Mostra que a metáfora é o recurso mais afeito a construir a língua literária e, no caso da poetisa, modelá-la em português. O estudo atesta que a linguagem conotativa da poetisa alcança os três níveis da língua e promove o inesperado e o distante da expressão comum. Afirma a importância da polifonia e da intertextualidade , além da excelência do discurso indireto livre na criação literária, não só da poetisa, mas de todo uso da língua portuguesa como ferramenta de expressão poética, principalmente se a intenção do autor é criar o discurso surrealista. A pesquisa mostra que há, na obra, um grande número de poemas em que predomina a linguagem religiosa católica. Ocorre a expressão da alma feminina , marcada com orgulho pela poetisa. A autora cria prosodemas, inaugura neologismos ,aproveitando todos os processos de criação vocabular. Assim, a obra se notabiliza pelo aproveitamento da sonoridade das palavras, pela escolha lexical inédita, por uma estrutura frasal apositiva, evocativa, sucinta e nominal, não escravizada às regras do registro culto como padrão literário. A tese reconhece que a autora lida eficientemente com as classes de palavras, com a construção nominal e com uma estruturação sintática peculiar, em que sobressai a oração adjetiva com função de sujeito, apesar de conter verbo: a oração adjetiva subjetivada. A essência da pesquisa são os conjuntos metafóricos, verdadeiros modelos universais, que permitem reconhecer a possível existência de uma língua literária em português. No mesmo contexto, focaliza um grupo de poemas chamados de telegráficos, curtos e de teor filosófico. Tal qualidade metafórica mostra a importância da poetisa Adélia Prado para a articulação da língua literária em língua portuguesa

Vectorial solution of Kukhtarev equations for doubly doped crystals and optimal choice of recording directions in nonvolatile holographic storage

Vectorial Kukhtarev equations modified for the nonvolatile holographic recording in doubly doped crystals are analyzed, in which the bulk photovoltaic effect and the external electrical field are both considered. On the basis of small modulation approximation, both the analytic solution to the space-charge field with time in the recording phase and in the readout phase are deduced. The analytic solutions can be easily simplified to adapt the one-center model, and they have the same analytic expressions given those when the grating vector is along the optical axis. Based on the vectorial analyses of the band transport model an optimal recording direction is given to maximize the refractive index change in doubly doped LiNbO3:Fe: Mn crystals. (c) 2007 Optical Society of America.