A helical peptide containing a majority of valyl residues. The crystal structure of t-butyloxy- carbonyl-(L-valyl-_-aminoisobutyryl)3-L-valyl methyl ester onohydrate

The monohydrate of the heptapeptide t-butyloxycarbonyl-(L-valyl-α-aminoiso-butyryl)3-L-valyl methyl ester crystallizes in the orthorhombic space group P212121 with four molecules in a unit cell with the dimensions α= 9.375, b = 19.413 and c = 25.878 ÅA. The structure has been solved by direct methods and refined to an R value of 0.059 for 3633 observed reflections. The molecule in the structure exists as a slightly distorted 310-helix stabilized by five 4 -> 1 intramolecular hydrogen bonds, indicating the overwhelming influence of α-aminoisobutyryl (Aib) residues in dictating helical fold even when a majority of residues in the peptide have a low intrinsic propensity to be in helices. Contrary to what is expected in helical structures, the valyl side chains, two of which are disordered, exhibit all three possible conformations. The molecules arrange themselves in a head-to-tail fashion along the c-axis. The columns thus generated pack nearly hexagonally in the crystal.

Turnout Intention and Social Networks

How can networking affect the turnout in an election? We present a simple model to explain turnout as a result of a dynamic process of formation of the intention to vote within Erdös-Renyi random networks. Citizens have fixed preferences for one of two parties and are embedded in a given social network. They decide whether or not to vote on the basis of the attitude of their immediate contacts. They may simply follow the behavior of the majority (followers) or make an adaptive local calculus of voting (Downsian behavior). So they either have the intention of voting when the majority of their neighbors are willing to vote too, or they vote when they perceive in their social neighborhood that elections are "close". We study the long run average turnout, interpreted as the actual turnout observed in an election. Depending on the combination of values of the two key parameters, the average connectivity and the probability of behaving as a follower or in a Downsian fashion, the system exhibits monostability (zero turnout), bistability (zero turnout and either moderate or high turnout) or tristability (zero, moderate and high turnout). This means, in particular, that for a wide range of values of both parameters, we obtain realistic turnout rates, i.e. between 50% and 90%.

Sistema seguro de votação eletrônica multi-células

Em uso desde a Grécia antiga e atualmente massificado na maioria dos países do mundo, o sistema de votação tradicional baseado em cédulas de papel possui diversos problemas associados à segurança, tais como dificuldades para evitar coerção do eleitor, venda do voto e substituição fraudulenta do eleitor. Além de problemas de usabilidade que acarretam erros de preenchimento da cédula e um processo de apuração lento, que pode durar dias. Ao lado disso, o sistema tradicional não fornece a contraprova do voto, que permite ao eleitor conferir se o seu voto foi corretamente contabilizado na apuração. Inicialmente acreditou-se que a informatização do sistema de votação resolveria todos os problemas do sistema tradicional. Porém, com a sua implantação em alguns países o sistema de votação eletrônica não mostrou-se capaz de fornecer garantias irrefutáveis que não tivesse sido alvo de alterações fraudulentas durante o seu desenvolvimento ou operação. A má reputação do sistema eletrônico está principalmente associada à falta de transparência dos processos que, em sua maioria, não proporcionam a materialização do voto, conferido pelo eleitor para fins de contagem manual, e nem geram evidências (contraprova) da correta contabilização do voto do eleitor. O objetivo deste trabalho é propor uma arquitetura de votação eletrônica que integra, de forma segura, o anonimato e autenticidade do votante, a confidencialidade e integridade do voto/sistema. O sistema aumenta a usabilidade do esquema de votação baseado em "Três Cédulas" de papel, implementando-o computacionalmente. O esquema oferece maior credibilidade ao sistema de votação através da materialização e contraprova do voto, resistência à coerção e ao comércio do voto. Utilizando esquemas de criptografia assimétrica e segurança computacional clássica, associado a um sistema de auditoria eficiente, a proposta garante segurança e transparência nos processos envolvidos. A arquitetura de construção modular distribui a responsabilidade entre suas entidades, agregando-lhe robustez e viabilizando eleições em grande escala. O protótipo do sistema desenvolvido usando serviços web e Election Markup Language mostra a viabilidade da proposta.

Financial equilibrium, voting procedures, and coalition structures in allocational mechanisms

This thesis is comprised of three chapters, each of which is concerned with properties of allocational mechanisms which include voting procedures as part of their operation. The theme of interaction between economic and political forces recurs in the three chapters, as described below.

Chapter One demonstrates existence of a non-controlling interest shareholders' equilibrium for a stylized one-period stock market economy with fewer securities than states of the world. The economy has two decision mechanisms: Owners vote to change firms' production plans across states, fixing shareholdings; and individuals trade shares and the current production / consumption good, fixing production plans. A shareholders' equilibrium is a production plan profile, and a shares / current good allocation stable for both mechanisms. In equilibrium, no (Kramer direction-restricted) plan revision is supported by a share-weighted majority, and there exists no Pareto superior reallocation.

Chapter Two addresses efficient management of stationary-site, fixed-budget, partisan voter registration drives. Sufficient conditions obtain for unique optimal registrar deployment within contested districts. Each census tract is assigned an expected net plurality return to registration investment index, computed from estimates of registration, partisanship, and turnout. Optimum registration intensity is a logarithmic transformation of a tract's index. These conditions are tested using a merged data set including both census variables and Los Angeles County Registrar data from several 1984 Assembly registration drives. Marginal registration spending benefits, registrar compensation, and the general campaign problem are also discussed.

The last chapter considers social decision procedures at a higher level of abstraction. Chapter Three analyzes the structure of decisive coalition families, given a quasitransitive-valued social decision procedure satisfying the universal domain and ITA axioms. By identifying those alternatives X* ⊆ X on which the Pareto principle fails, imposition in the social ranking is characterized. Every coaliton is weakly decisive for X* over X~X*, and weakly antidecisive for X~X* over X*; therefore, alternatives in X~X* are never socially ranked above X*. Repeated filtering of alternatives causing Pareto failure shows states in X^n*~X^((n+1))* are never socially ranked above X^((n+1))*. Limiting results of iterated application of the *-operator are also discussed.

Scale-invariant vote-based 3D recognition and registration from point clouds

This chapter presents a method for vote-based 3D shape recognition and registration, in particular using mean shift on 3D pose votes in the space of direct similarity transformations for the first time. We introduce a new distance between poses in this spacethe SRT distance. It is left-invariant, unlike Euclidean distance, and has a unique, closed-form mean, in contrast to Riemannian distance, so is fast to compute. We demonstrate improved performance over the state of the art in both recognition and registration on a (real and) challenging dataset, by comparing our distance with others in a mean shift framework, as well as with the commonly used Hough voting approach. © 2013 Springer-Verlag Berlin Heidelberg.

The Irish House of Lords, 1780-1800: politics and ideology

This thesis covers the Irish House of Lords in the last two decades of its life. A number of important themes run through the work - the regency crisis, patronage, the management of the Lords, the relationship between the Lords and Commons. These themes, explored from different angles, are vital to an understanding of the political role of the upper house in the 1780s and 1790s. This study is confined to the Lords as a political institution and thus its judicial role as final court of appeal, which was restored to it in 1782, will not be explored here. The thesis consists of two parts. Part one examines the structure and powers of the House of Lords while part two looks at the parties and policies of the house. Chapter one discusses the British constitution as imposed upon Ireland. Chapter two suggests the reasons why constitutional changes were introduced in 1782, and looks at the contribution made by the Irish House of Lords in securing these changes. Chapter three explores the various channels of influence which the peers enjoyed. Chapter four explores the sometimes tense relationship between Lords and Commons. Chapter five examines management of the House of Lords by Dublin Castle. Part two, begins at chapter six. This chapter explores the leadership of both parties within the Lords. Chapter seven looks at how patronage was used to reward those who were loyal to the government. Chapter eight explores the influence of the Whig opposition. Chapter nine looks at the controversial attempts made by Pitt and his ministry during the 1790s to win the support of catholics and turn them from the lure of French ideas, and of the response of the peers to these attempts. Chapter ten is concerned with the relationship between the peers of the House of Lords and the lords lieutenant during the 1790s. Chapter eleven looks at the Union and the House of Lords and attempts to answer the question historians have long asked: why did the Irish parliament and the House of Lords in particular, look favourably on the proposed union of the two kingdoms and the end of their own institution? The House of Lords in the closing decades of the eighteenth century was an institution within which the wealth and power of the kingdom could be found. Its members were politically active, both inside and outside the house. It contained a majority who saw the Crown as the source of stability, but it was a living and evolving political organism and therefore it contained men who believed that the Crown should have its influence limited. This evolution is also demonstrated in its desire for political change in 1782 and 1788. Its last, and perhaps most radical decision, was to vote for its own demise in 1900.

Surviving as an underrepresented minority scientist in a majority environment.

I believe the evidence will show that the science we conduct and discoveries we make are influenced by our cultural experience, whether they be positive, negative, or neutral. I grew up as a person of color in the United States of America, faced with challenges that many had as members of an underrepresented minority group. I write here about some of the lessons I have learned that have allowed me to survive as an underrepresented minority -scientist in a majority environment.

Indigenous rights in Chile: National identity and majority group support for multicultural policies

We examine support for policies affecting indigenous ethnic minorities in Chile. Specifically, we examine the role of national group definitions that include the largest indigenous group—the Mapuche—in different ways. Based on questionnaire data from nonindigenous Chilean students (N = 338), we empirically distinguish iconic inclusion, whereby the Mapuche are seen as an important part of Chile's history and identity on the one hand, from egalitarian inclusion, which represents the Mapuche as citizens of equal importance to the nonindigenous majority on the other. Both forms of inclusion positively predict support for indigenous rights, independent of participants' political affiliation, strength of national identification, and social distance. A second study (N = 277) replicates this finding whilst controlling for right-wing authoritarianism, social dominance orientation, blind patriotism, and constructive patriotism. It also finds iconic inclusion to be predictive of a pro-Mapuche position regarding the unrest over the issue of ancestral land in 2009. We conclude that understanding how national identity affects attitudes about minority rights necessitates appreciating the importance of particular meanings of nationality, and not only the strength of identification.