We introduce a spatial cost topology in the network formation model analyzed by Jackson and Wolinsky, <i>Journal of Economic Theory </i><b>71 </b> (1996), 44--74. This cost topology might represent geographical, social, or individual differences. It describes variable costs of establishing social network connections. Participants form links based on a cost-benefit analysis. We examine the pairwise stable networks within this spatial environment. Incentives vary enough to show a rich pattern of emerging behavior. We also investigate the subgame perfect implementation of pairwise stable and efficient networks. We construct a multistage extensive form game that describes the formation of links in our spatial environment. Finally, we identify the conditions under which the subgame perfect Nash equilibria of these network formation games are stable. We analyze the dynamic implications of learning in a large population coordination game where both the actions of the players and the communication network evolve over time. Cost considerations of social interaction are incorporated by considering a circular model with endogenous neighborhoods, meaning that the locations of the players are fixed but players can create their own communication network.The dynamic process describing medium-run behavior is shown to converge to an absorbing state, which may be characterized by coexistence of conventions. In the long run, when mistake probabilities are small but nonvanishing, coexistence of conventions is no longer sustainable as the risk-dominant convention becomes the unique stochastically stable state. We create and investigate a system that is capable of observing the accumulation of social capital and the effect of social capital accumulation on behavior of individually rational players. In the first model, we develop a restricted system to show that social capital forms and is maintained at a steady state level. The resulting network is the chain. The second model uses a congestion function in conjunction with social capital to show a network emerge that contains links that costlier than those in the chain network. / Ph. D.

We study several different models of extended bodies in gravitational fields. Firstly, we revisit the glider model of a dumbbell-like oscillating body. We develop an independent scheme to integrate the equations of motion. We study the radial fall of a Newtonian spring, calculate the position shifts of the spring and find the critical value of the spring constant which cannot overcome the tidal forces. We argue that the relativistic glider model is unphysical due to its behaviour in the critical regions. Secondly, we show that Dixon's theory of extended bodies predicts a geodesic motion of the centre of mass in maximally symmetric spacetimes. We prove that a system of test particles can be described by a conserved stress-energy tensor and we evaluate the position shifts of the glider model in the maximally symmetric spacetimes, showing its disagreement with Dixon's theory. We thus conclude again that the glider model must be rejected. And thirdly, we study a model of an extended body consisting of interacting particles, which is in accord with Dixon's theory. We calculate the position shifts for this model and show that the model does not predict any measurable swimming effect. Finally, we estimate the numerical error of the calculation by finding the position shifts of the model in maximally symmetric...

<p>Ab-initio results of the core-level shift and the distribution about the average for the 3<i>d</i>_5/2 electrons of Ag, Pd and 2<i>p</i>_3/2 of Cu are presented for the face-centered-cubic AgPd and CuPd random alloys. The complete screening model, which includes both initial and final states effects in the same scheme, has been used in the investigations. </p><p>The alloys have been modeled with a supercell containing 256 atoms. Density-functional theory calculations are carried out using the locally self consistent Green's function approach. </p><p>Results from the calculations clearly shows that the core-level shift distributions characteristic is Gaussian, but the components reveals a substantial difference in the FWHM (Full-Width at Half-Maximum). Comparison between the experimental and the calculated broadening shows a remarkable agreement.</p>

Ab-initio results of the core-level shift and the distribution about the average for the 3d5/2 electrons of Ag, Pd and 2p3/2 of Cu are presented for the face-centered-cubic AgPd and CuPd random alloys. The complete screening model, which includes both initial and final states effects in the same scheme, has been used in the investigations. The alloys have been modeled with a supercell containing 256 atoms. Density-functional theory calculations are carried out using the locally self consistent Green's function approach. Results from the calculations clearly shows that the core-level shift distributions characteristic is Gaussian, but the components reveals a substantial difference in the FWHM (Full-Width at Half-Maximum). Comparison between the experimental and the calculated broadening shows a remarkable agreement.

Die Arbeit beschreibt ein Modell, dass den Materialfluss in Transport- und Puffersystemen mit Hilfe eines agenten-basierten Ansatzes realistisch abbildet. Auf der Basis von Produktionsprogrammen werden individuelle Güter in beliebigen Netzwerkstrukturen mit Hilfe direkter und indirekter Interaktionen behinderungsvermeidend gesteuert. / The thesis describes a model that realistically illustrates the material flow in transport and buffer systems by means of an agent-based approach. Individual goods are steered hindrance-avoiding in arbitrary network structures based on production programs by means of direct and indirect interactions.

The potential use of common bean land varieties regarding to agronomic performance and cooking quality was little evaluated by plant breeding programs. Therefore, objectives of this study were to evaluate the phenological, morphological, grain yield, absorption percentage and cooking quality characters of common bean land varieties obtained from different location; to study the correlations between phenological, morphological and grain yield characters; to estimate the direct and indirect effects of the characters on grain yield; to select common bean land varieties with high agronomic performance and reduced cooking time for family farms grown and for crosses in plant breeding programs. For this, 23 common bean cultivars, being nineteen land varieties and four cultivars developed by research, were evaluated in field experiments installed at the Federal Institute Farroupilha (IFF), Alegrete, and at Federal University of Santa Maria (UFSM), Santa Maria, in growing season 2012/2013. A significant cultivar x location interaction was observed for the characters number of days from emergence to flowering, cycle, height of insertion of the first pod, height of insertion of the final pod, number of pods per plant, grain yield, b* chromaticity value, absorption percentage and cooking time. Preto Miúdo and Cavalo Rajado land varieties showed high grain yield and agronomic characters desirable for grown. The Banana and Perdiz land varieties showed reduced cooking time, however, presented low agronomic performance and type of grain out of commercial standards, which makes difficult its indication for grown. The number of pods per plant showed positive linear correlation of intermediate magnitude with the grain yield (r = 0.670), and the highest direct effect (0.632). There is presence of genetic variability among the common bean land varieties studied, which enables obtaining genetic gain in breeding programs using this germplasm. The indirect selection for the number of pods per plant is important component in predicting grain yield in common bean land varieties. Preto Miudo and Cavalo Rajado land varieties show high agronomic performance and its use is indicated for cultivation on family farms and for crosses in plant breeding programs. / O potencial de uso das cultivares crioulas de feijão quanto ao desempenho agronômico e a qualidade de cozimento foi pouco avaliado pelos programas de melhoramento. Sendo assim, foram objetivos deste trabalho avaliar os caracteres fenológicos, morfológicos, da produção, da porcentagem de absorção e de qualidade de cozimento de cultivares crioulas de feijão obtidas em diferentes locais; estudar as correlações fenotípicas entre os caracteres fenológicos, morfológicos e da produção; estimar os efeitos diretos e indiretos dos caracteres avaliados sobre a produtividade de grãos; selecionar cultivares crioulas de feijão com elevado desempenho agronômico e reduzido tempo de cozimento para cultivo na agricultura familiar e para uso em cruzamentos dirigidos em programas de melhoramento. Para tanto, 23 cultivares de feijão, sendo 19 crioulas e quatro desenvolvidas pela pesquisa, foram avaliadas em experimentos de campo instalados em área do Instituto Federal Farroupilha (IFF), Alegrete, e da Universidade Federal de Santa Maria (UFSM), Santa Maria, no cultivo de safra 2012/2013. Interação cultivar x local significativa foi observada para os caracteres número de dias da emergência à floração, ciclo, altura de inserção da primeira vagem, altura de inserção da última vagem, número de vagens por planta, produtividade de grãos, valor de cromaticidade b*, porcentagem de absorção e tempo de cozimento. As cultivares crioulas Preto Miúdo e Cavalo Rajado apresentaram alta produtividade de grãos e caracteres agronômicos desejáveis para o cultivo. As cultivares Banana e Perdiz apresentaram tempo de cozimento reduzido, porém desempenho agronômico inferior e tipo de grão fora de padrões comerciais, o que dificulta a sua indicação para o cultivo. O número de vagens por planta apresentou correlação linear positiva de intermediária magnitude com a produtividade de grãos (r= 0,670) e o maior efeito direto (0,632) Variabilidade genética é observada entre as cultivares crioulas de feijão avaliadas, o que possibilita a obtenção de ganhos genéticos em programas de melhoramento com o uso deste germoplasma. A seleção indireta pelo número de vagens por planta é indicada na predição da produtividade de grãos em cultivares crioulas de feijão. As cultivares Preto Miúdo e Cavalo Rajado apresentam alto desempenho agronômico e seu uso é indicado para cultivo na agricultura familiar e para uso em programas de melhoramento.

Management was once described as the art of getting things done through the efforts of oneself and other people (Follett, 1941) and is functionalised through acts of planning, organising, leading and controlling tasks and people for pre-defined objectives. These four cardinal pillars of management are translated into various models, tools and techniques of best practice of how to manage. While acknowledging that the substance of the current management models, tools and techniques have for years broadly contributed to how organisations are run, my research sheds more light on the shortcomings underlying some of the assumptions and ways of thinking behind these models and tools. My research findings based on my experience in working for the Department for International Development suggests that management practice and organisational change occur in the context of human power relationships in which people constrain and enable each other on the basis of human attributes such as identities, attitudes, values, perceptions, emotions, fears, expectations, motives and interests. I argue that these human attributes, human power relations and the totality of human emotions arise in the social, and understanding the ways in which these attributes shape local interaction and daily human relating is critical in making sense of the reality of organisational change and management. I suggest that management practice occurs in the context of everyday politics of human relating. It is that type of politics that takes place within families, groups of people, organisations, communities, and indeed throughout all units of society around the distribution of power, wealth, resources, thoughts and ideas. This way of thinking has enormous implications for the way we conceptualise management theory and practice. I am suggesting that managers do not solely determine, nor do employees freely choose their identities, attitudes, values, perceptions, emotions, fears, expectations and motives. These human dimensions arise from social relationships and personal experiences. As such, it is simply not for a manager to decide or force other employees on which of these human attributes to influence their behaviour. I am arguing that the social nature of management practice and role of human agents is inherently complex and cannot, in the scientific sense, be adequately reduced to discrete, systematic, complete and predictive models, tools and techniques without losing some meaning of what we do in management.

Die Arbeit beschreibt ein Modell, dass den Materialfluss in Transport- und Puffersystemen mit Hilfe eines agenten-basierten Ansatzes realistisch abbildet. Auf der Basis von Produktionsprogrammen werden individuelle Güter in beliebigen Netzwerkstrukturen mit Hilfe direkter und indirekter Interaktionen behinderungsvermeidend gesteuert. / The thesis describes a model that realistically illustrates the material flow in transport and buffer systems by means of an agent-based approach. Individual goods are steered hindrance-avoiding in arbitrary network structures based on production programs by means of direct and indirect interactions.