This research on gender and tomato production in rural sub-county of Busukuma in Uganda explores the roles that distance and mobility play in adoption of environmentally friendly crop protection practices. Uganda's National Agricultural Research Organization (NARO) prioritized blight and bacterial wilt as significant detrimental crop diseases for tomatoes, an important high-value horticulture crop. Tomato farmers have also identified these diseases as primary constraints for crop production and have employed chemical pesticides to reduce crop losses. One focus of the Integrated Pest Management Collaborative Research Support Program (IPM CRSP), which is managed by Virginia Tech, has been the development of an IPM package to lower the use of pesticides in tomato production while reducing the incidence of such crop diseases. Recommended practices increase yields, save money on inputs, and improve health conditions. Women are responsible for the majority of food production in sub-Saharan Africa; therefore, an understanding of women's issues is critical for the success of agricultural projects, such as the IPM program in Uganda. This research seeks to determine problems women farmers face in adopting the farming practices recommended by the IPM CRSP. Gender-specific constraints make adopting IPM more costly and time-consuming for women. Surveys, interviews, focus group discussions and GIS analysis were completed to determine if adoption of the recommended IPM package is affected by gender constraints in mobility and distances to inputs. / Master of Science

This study is divided into two main parts. The first section deals with mathematical properties of distance functions. The fp norm is analyzed as a function of its parameter p, leading to useful insights for fitting this distance measure to a transportation network. Properties of round norms are derived, which allow us later to generalize some well-known results. The properties of a norm raised to a power are also investigated, and these prove useful in our subsequent analysis of location problems with economies or diseconomies of scale. A positive linear combination of the Euclidean and rectangular distance measures, which we term the weighted one-two norm, is introduced. This distance function provides a linear regression model with interesting implications on the characterization of transportation networks. A directional bias function is defined, and examined in detail for the Pp and weighted one-two norms. In the second part of this study, several properties are derived for various forms of the continuous minisum location model. The Weiszfeld iterative solution procedure for the standard Weber problem with fp distances is also examined, and global and local convergence results obtained. These results are extended to the mixed-norm problem. In addition, optimality criteria are derived at non-differentiable points of the objective function. / Thesis / Doctor of Philosophy (PhD)

No description available.

No description available.

No description available.

No description available.

We study a generalization of the problem of finding bounds on the number of discrete chains, which itself is a generalization of the Erdős unit distance problem. Given a set of points in Euclidean space and a tree graph consisting of a much smaller number of vertices, we study the maximum possible number of tree graphs which can be represented by a prescribed tree graph. We derive an algorithm for finding tight bounds for this family of problems up to chain bound discrepancy, and give upper and lower bounds in special cases. / Master of Science / We study a generalization of the problem of finding bounds on the number of discrete chains, which itself is a generalization of the Erdős unit distance problem, a famous mathematics problem named after mathematician Paul Erdős. Given a set of points, and a tree graph of a much smaller amount of vertices, we study the maximum possible number of tree graphs which can be represented by a prescribed tree graph. We derive an algorithm for finding tight bounds for this family of problems up to chain bound discrepancy, and give upper and lower bounds in special cases.

This study addressed the relational maintenance strategies and the meaning 23 to 35 year old students attributed to their long-distance dating relationships. Ten participants completed in depth interviews exploring the thoughts and feelings individuals held about their current long-distance partner and relationship. Also, commitment and quality of alternatives were addressed including the strengths and weaknesses of the respondent's relationship. Common themes of strong friendship, absolute trust, commitment to one partner, and using the technique of reminiscing were all dominant issues that emerged from the interview data. Social network approval as well as positive role models in the form of older siblings was also instrumental in lending support to the success and general positive attitude felt by participants about the geographic separation. Methods of communication included the telephone and e-mail, which was substituted or supplementary when high phone bills created financial concerns for the respondents. Variation in physical visitation was due to the intersection of academic schedule, affordable transportation, attitude towards work disruptions, geographic distance, and a general willingness to travel. Participants told a story of the geographic separation as both a temporary and necessary inconvenience, rather than a major obstacle or focal point of the relationship. Future directions for studying long-distance dating relationships include collecting couple data and examining gender differences to determine if sex has an impact on how geographic separation is viewed. / Master of Science

No description available.

Este trabalho tem como objetivo discutir o conceito formal de distância em matemática, visando depois apresentar exemplos do conceito de distância em situações do dia a dia. Em geral com esse trabalho pretendemos que o leitor menos familiarizado entenda a importância do conceito matemático de distância. Distância é muito mais que o comprimento do segmento entre dois pontos e isso será apresentado em cada capítulo. O assunto foi inspirado pelo livro Encyclopedia of Distances Deza Michel Marie (2009), no qual são apresentados, espaços métricos, métricas em várias áreas e aplicações. No segundo capítulo, será apresentado a definição de espaços métricos. No terceiro capítulo serão apresentados alguns exemplos de métricas. As três primeiras métricas, as mais comuns: métricas euclidiana e máxima em R e R2. Também serão apresentadas as generalizações de cada uma delas em Rn. O próximo capítulo, o quarto, é destinado a apresentar o estudo sobre espaços normados, pois por meio desses conceitos pode-se analisar as distâncias entre vetores e matrizes. Veremos que a relevância dessas distâncias auxilia, por exemplo, na compreensão de aproximações de soluções de sistemas. No capítulo de distância de funções será apresentado um breve comentário sobre a série de Fourier, com relação ao método da aproximação através da decomposição de funções periódicas. Para analisar o quanto as funções trigonométricas estão se aproximando, usa-se o conceito de distância entre funções, as medições são feitas de acordo com as aproximações vão aumentando, essa distância \"erro\" entre elas tende a zero. Na teoria dos códigos, é preciso introduzir o conceito de distância entre \"palavras\", isso permite verificar se o código enviado teve alguma alteração, provocada por uma interferência ou ruídos durante a trajetória. Em algumas situações, o código consegue corrigir e compreender a palavra enviada mesmo tendo sofrido alterações no percurso. Nestes casos, há o estudo da métrica de Hamming. Já pela métrica de Hausdoorf, proposta pelo matemático de mesmo nome, é possível calcular com maior precisão a distância entre conjuntos fechados e limitados. Esta métrica pode ser utilizada em estudos de reconhecimento facial, por exemplo, pois as imagens das faces são transformadas em nuvens de pontos. Além disso, através do algoritmo de Dijkstra será apresentado a distância entre os vértices de um grafo convexo. Existem várias aplicações de distância entre grafos e uma delas é a questão de minimizar o custo decorrente do deslocamento entre uma transportadora e o local de entrega por exemplo. Para finalizar à discussão da importância do consenso de distância, será apresentada uma distância entre genes. Dentro deste tema, o principal cientista foi Thomas Morgan, que por meio de seus estudos conseguiu criar o primeiro mapeamento genético. Com isto, pode relacionar o conceito de distância entre genes à taxa de recombinação gênica. Finalmente, foi elaborada uma atividade com alunos do ensino médio com o objetivo de analisar os conhecimentos que os estudantes têm sobre distância. Esta atividade também foi importante para que os alunos pudessem compreender a necessidade de formalizar matematicamente este conceito e, principalmente, motivá-los por meio da apresentação de aplicações sobre distância, em diferentes âmbitos. / This work has as objective to discuss the formal concept of distance in mathematics, aiming to present examples of the distance concept in everyday situations. In general with this work we want the less familiar reader to understand the importance of the mathematical concept of distance. Distance is much more than the length of the segment between two points and this will be presented in each chapter. The subject was inspired by the book Encyclopedia of Distances Deza Michel Marie (2009), in which are presented, metric spaces, metrics in different areas and applications. In the second chapter, the definition of metric spaces will be presented. In the third chapter some examples of metrics will be presented. The first three metrics, the most common: usual, Euclidean, and maximum metrics in R and R2. Also the generalizations of each of them were presented in Rn. The next chapter, the fourth, is intended to show the study on normed spaces, because through these concepts we can analyze the distances between vectors and matrices. We will see that the relevance of these distances helps in the understanding of systems solutions approximation. In the chapter on distance of functions, a brief comment about Fourier series was presented, regarding the method of approximation through the decomposition of periodic functions. In order to analyze how the trigonometric functions are approaching, the concept of distance between functions is used, the measurements are made as the approximations increase, this distance \"error\" between them tends to zero. In codes theory, it is necessary to introduce the concept of distance between \"words\", this allows to verify if the code had some alteration, caused by an interference or noises during the trajectory. In some situations, the code can correct and understand the sent word even though it has undergone changes in the route. In these cases, there is Hammings metrics study. By the Hausdoorf metric, proposed by the mathematician of the same name, it is possible to calculate with more precision the distance between closed and limited sets. This metric can be used in face recognition studies, for example, because face images are transformed into clouds of dots. Then, through the Dijkstras algorithm will be presented the distance between the vertices of a convex graphic. There are several applications of distance between graphics and one of them is the issue of minimizing the cost of moving between a local carrier company and the place of delivery, for example. To finish the discussion about the importance of distance consensus, the distance between genes will be presented. Within this theme, the main scientist was Thomas Morgan, who through his studies managed to create the first genetic mapping. With this, he was able to relate the concept of distance between genes to the rate of gene recombination. Finally, an activity was elaborated with high school students with the objective of analyzing students knowledge about distance. This activity was also important so that the students could understand about a necessity to formalize this concept mathematically and, mainly, to motivate them through the presentation of applications on distance, in different scopes.