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Rayleigh matroids are a class of matroids with sets of bases that satisfy a strong negative correlation property. Interesting characteristics include the existence of an efficient algorithm for sampling the bases of a Rayleigh matroid [7]. It has been conjectured that the class of Rayleigh matroids satisfies Mason’s conjecture [14]. Though many elementary properties of Rayleigh matroids have been established, it is not known if this class has a finite set of minimal excluded minors. At this time, it seems unlikely that this is the case. It has been shown that there is a single minimal excluded minor for the smaller class of binary Rayleigh matroids [5]. The aim of this thesis is to detail our search for the set of minimal excluded minors for ternary Rayleigh matroids. We have found several minimal excluded minors for the above class of matroids. However, our search is incomplete. It is unclear whether the set of excluded minors for this set of matroids is finite or not, and, if finite, what the complete set of minimal excluded minors is. For our method to answer this question definitively will require a new computer program. This program would automate a step in our process that we have done by hand: writing polynomials in at least ten indeterminates as a sum with many terms, squared.

Rayleigh matroids are a class of matroids with sets of bases that satisfy a strong negative correlation property. Interesting characteristics include the existence of an efficient algorithm for sampling the bases of a Rayleigh matroid [7]. It has been conjectured that the class of Rayleigh matroids satisfies Mason’s conjecture [14]. Though many elementary properties of Rayleigh matroids have been established, it is not known if this class has a finite set of minimal excluded minors. At this time, it seems unlikely that this is the case. It has been shown that there is a single minimal excluded minor for the smaller class of binary Rayleigh matroids [5]. The aim of this thesis is to detail our search for the set of minimal excluded minors for ternary Rayleigh matroids. We have found several minimal excluded minors for the above class of matroids. However, our search is incomplete. It is unclear whether the set of excluded minors for this set of matroids is finite or not, and, if finite, what the complete set of minimal excluded minors is. For our method to answer this question definitively will require a new computer program. This program would automate a step in our process that we have done by hand: writing polynomials in at least ten indeterminates as a sum with many terms, squared.

Development asks that the inequity and unsustainability of the widening gap between rich and poor be narrowed, ultimately impacting on households in the most economically excluded communities. Local community-based organisations (CBOs) provide much of the organisational fabric through which development is delivered. Largely resourced by the poorest themselves, many of these CBOs aspire to attracting funds from the development aid industry. In attempting to comply with the rules of these funding sources and compete in funding relationships, organisations become players in the funding game fraught with power imbalance and seemingly contradictory incentives. Neither the funding agencies, intent on disbursement, nor the CBOs in their desire to build organisations and contribute to their communities, seem aware of the true costs of these relationships. Aid funding is complex, operating at numerous levels, across a multiplicity of varied organisations, stakeholders and contexts. Over the last 60 years, the aid industry has evolved complicated and highly engineered mechanisms to manage relationships with funding recipients, including detailed conventions for evaluation. As part of contractual obligation, criteria for success are pre-defined; outcomes are predicted; and targets are projected. Development, however, is not linear or predictable. It is contradictory and complex. Despite objections and alternatives since the late 1980s, ‘conventional’ linear, simplistic rationale has dogged the development industry. The HIV support sector as a focus for funding, capacity building and service contracts from government and international aid agencies, offers rich examples of aid industry dynamics. This research, set amongst small but established CBOs working in HIV/AIDS support in Soweto and Lawley (Gauteng) and Mabeskraal (North West Province), explores alternative evaluation approaches, methodologies and principles, based on grounded evaluation. Two models are tested and compared. Firstly, inward-looking, organisation-based, reflective self-evaluation using Stories and Metaphor. Than secondly, outward-looking, community research using a Most Significant Change approach. The evaluation processes developed help participating CBOs describe success and outcomes against their own criteria. The approaches use narrative, visual and metaphorical formats. The central purpose of the research is meta-evaluation aimed at an effective process using iterative, cumulative action research based on the principles of grounded theory. Meta-evaluation data included descriptions of the processes and the nature of evaluation results. They are analysed using reflection, learning and re-design in an action research cycle. The results provide both practical insights into conducting evaluation, and the principles of effective development in a CBO setting. They demonstrate that grounded evaluation can be used to understand organisational dynamics and programme outcomes. Participatory methods, particularly visual and verbal communication, are shown to be far superior to written communication in this setting. The results demonstrate the mutual compatibility and ethical inseparability of organisation development with evaluation, providing insight into the practice of utilisation-based evaluation. The value of appreciative inquiry and the risks of accusatory inquiry are described. A thread that runs through the results highlights the impact of power, ownership and process use in effective evaluation. The research has also elaborated some of the intractable contradictions and conundrums in development aid. Money carries the power vested in global economics and market forces. In making funding judgements, evaluators purvey the power of wealth inequity: the very power imbalance which itself purports to address. As a development practitioner, an evaluator’s role should be to facilitate pathways out of dependent mindsets. As gatekeepers to financial support, however, their work entrenches distortions in perceptions of wealth and power. These complex interactions of power and ownership demand moderation and compromise. The industry requires investment of greater energy into theoretical, methodological and practical research. Suggestions for such research are included. Without fresh creativity, development and evaluation will remain frustrated forces within an entrenched, self-perpetuating system of inequity and disparity. / Thesis (PhD)--University of Pretoria, 2010. / Human Resource Management / unrestricted

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Protein folding is the process during which an extended and unstructured polypeptide converts to its compact folded structure that is most often the functional state. The process has been characterized extensively in dilute buffer in-vitro during the last decades but the actual biological place for this process is the inside of living cells. The cytoplasm of a cell is filled with a plethora of different macromolecules that together occupy up to 40% of the total volume. This large amount of macromolecules restricts the available space to each individual molecule, which has been termed macromolecular crowding. Macromolecular crowding results in excluded volume effects and also increases chances for non-specific interactions. Macromolecular crowding should favor reactions that lead to a decrease in the total occupied volume by all molecules, such as folding reactions. Theoretical models have predicted that the stability of protein folded states should increase in presence of macromolecular crowding due to unfavorable effects on the extended unfolded state. To understand protein folding and function in living systems, we need to have a defined quantitative link between in-vitro dilute conditions (where most biophysical experiments are made) and in-vivo crowded conditions. An important question is thus how macromolecular crowding modifies the biophysical properties of a protein. The work underlying this thesis focused on how macromolecular crowding tunes protein equilibrium stability and kinetic folding processes. To mimic the crowded cellular environment, synthetic sugar-based polymers (Dextrans of different sizes and Ficoll 70) were used as crowding agents (crowders) in controlled in-vitro experiments. In contrast to previous studies which often have focused on one protein and one crowder at a time, the goal here was to make systematic analyses of how size, shape and concentration of the crowders affect both equilibrium and kinetic properties of structurally-different proteins. Three model proteins (cytochrome c, apoazurin and apoflavodoxin) were investigated under crowding by Ficoll 70 and different-size Dextrans, using various spectroscopic techniques such as far-UV circular dichroism and intrinsic tryptophan fluorescence. Thermodynamic models were applied to explain the experimental results. It was discovered that equilibrium stability of all three proteins increased in presence of crowding agents in a crowder concentration dependent manner. The stabilization effect was around 2-3 kJ/mol, larger for the various Dextrans than for Ficoll 70 at the same g/l, but independent of Dextran size (in the range 20 to 70 kDa). To further investigate the cause for the stabilization a theoretical crowding model was applied. In this model, Dextran and Ficoll were modeled as elongated rods and the protein was represented as a sphere, where the folded sphere representation was smaller than the unfolded sphere representation. It is notable that the observed stability changes could be reproduced by this model taking only steric interactions into account. This correlation showed that when using sugar-based crowding agents, excluded volume effects could be studied in isolation and there were no contributions from nonspecific interactions. Time-resolved experiments with apoazurin and apoflavodoxin revealed an increase in the folding rate constants while the unfolding rates were invariant in the presence of crowding agents. For apoflavodoxin and cytochrome c, the presence of crowding agents also altered the folding pathway such that it became more homogeneous (cytochrome c) and it gave less misfolding (apoflavodoxin). These results showed that macromolecular crowding restricts the conformational space of the unfolded polypeptide chain, makes the conformations more compact which, in turn, eliminates access to certain pathways. The results from kinetic and equilibrium measurements on three model proteins, together with available data from the literature, demonstrate that macromolecular crowding effects due to volume exclusion are in the order of a few kJ/mol. Considering the numerous concentration balances and cross-dependent reactions of the cellular machinery, small changes in energetics/kinetics of the magnitudes found here can still have dramatic consequences for cellular fitness. In fact local and transient changes in macromolecular crowding levels may be a way to tune biochemical reactions without invoking gene expression.

Made available in DSpace on 2014-06-11T19:29:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2004Bitstream added on 2014-06-13T18:39:17Z : No. of bitstreams: 1 pacheco_rd_me_botfm.pdf: 1115076 bytes, checksum: 93ce87fbe860ad9cdd822743e8e7e4b9 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A deficiência física é um fenômeno biológico e social, que atinge aproximadamente 10% da população e traz grandes dificuldades para a vida cotidiana do portador e de sua família. Dificuldades que não estão relacionadas apenas às limitações auditivas, visuais, mentais, físicas e/ou motoras, mas principalmente àquelas imposta pela sociedade e pelo capital e se manifesta muitas vezes através da segregação, do estigma e do preconceito. Nesse estudo limitamo-nos a estudar os portadores de deficiência física, buscando descrever e discutir as condições em que eles vivem. Essa pesquisa foi desenvolvida na cidade de Botucatu – São Paulo. Inicialmente foi feito um inquérito em 25% dos domicílios da área urbana de Botucatu, para localizar os portadores de deficiência física. Identificados os endereços, selecionamos apenas os que residem na área do Centro Saúde Escola. Fizemos uma caracterização biomédica e social dos portadores de deficiência física e suas famílias, utilizando um roteiro com questões abertas e fechadas. Foram entrevistadas 82 famílias e 93 pessoas portadoras de deficiência física. Observamos que no município de Botucatu há uma maior prevalência de pessoas portadoras de deficiência física em áreas de alta exclusão social. Em relação às pessoas portadoras de deficiência física temos que 51% são do sexo masculino. A idade média é de 49 anos, 36,3% tem mais de 60 anos. A escolaridade média é 4,2 anos de estudos. A maioria é aposentado, pensionista ou inativo (71%). Apenas 14,5% estão ocupados e destes, 45,5%, estão inseridos em atividades predominantemente manuais não especializadas. O rendimento médio é de 0,9 salários mínimos e 39,2% não possuem nenhuma fonte de renda. A família das pessoas portadora de deficiência física tem em média 3,7 pessoas, 57,5% das famílias são do... . / Physical disability is a social and biological phenomenon, which assails around 10% of the population and brings significant difficulties to the everyday life of the disabled person. Such difficulties are not only related to auditory, visual, mental, physical and/or motor limitations but mainly to those established by society and capital and most of the times it is demonstrated through segregation, stigma and prejudice. Physically disabled people were the aim of this study and their living conditions were discussed and described. This research was carried in Botucatu – São Paulo. At first, a survey was performed in 25% of houses in the urban area of Botucatu to identify the physically disabled people. When the addresses were identified, one selected only the ones, which lived at “Centro de Saúde Escola” vicinities. A biomedical and social characterization was performed on physically disabled people and their families, following open and closed questions round. One observed that in Botucatu there is a higher prevalence of physically disabled people among high social excluded ones. Related to physically disabled people, 51% are male. Average age is 49 years old, 36.3% is more than 60 years old. Average education is 4.2 years of study, most of them are retired, pensioner or inactive. (71%). Only 14.5% have an occupation and from these 45.5% are inserted in predominantly non-specialized manual activities. Average income is 0.9 minimum wages and 39. 2% do not have any income. The family of physically disabled people has an average of 3.7 people; 57.5% of families are cellular like, and from these, 18.8% are extended families, which are being dispersed. According to the scale used by Seade Foundation, 17% of families are considered wretched, 71% poor and 12,1% not poor. The major part of physical disability was acquired in adulthood (43%), and the main causes are chronic-degenerative... (Complete abstract, click electronic address below).

Magister Commercii - MCom / The literature on financial inclusion and poverty connections has received considerable attention recently. There exist a scarcity of local studies examining the relationship between financial inclusion (FI) and poverty. Precisely, there is a lack of local studies who previously used FinScope data to investigate the mentioned relationship in South Africa. This study is motivated to fill the gap. To achieve the aims, the study will source data from FinScope (a secondary data) for the periods of 2011 and 2016. The Foster-Greer-Thorbecke indices were used to measure the level of poverty, while the lower-bound poverty (LBPL) line was used to differentiate the poor from the non-poor. Principal Component Analysis (PCA) was also applied to derive the financial inclusion index (FII). Probit regressions were run to measure the likelihood of being poor and being financially excluded. Ordinary Least Squares were run to identify the nature of the relationship between the dependent and the independent variables. Lastly, bivariate regression was also run to test the relationship between poverty and financial exclusion.

Socially excluded localities are found all over the Czech Republic. They are whole neighbourhoods, houses or streets, usually situated on the outskirts of towns, threatened by a symbolic, territorial, cultural, economic and social exclusion. The inhabitants of the socially excluded localities usually have debts with the town, which is the reason why they were moved to this locality. Problems that frequently occur in the socially excluded localities include insufficient education, high unemployment rate, financial problems and a high occurrence of socially pathological phenomena. Drawing on the facts obtained, it is possible to recommend social services that missing here at present. At the same time, the results of this thesis may serve to social workers as a detailed survey of the social situation of the locality in question.

The author in this thesis titled Children and young people from socially excluded localities and their failure in non-formal education deals with the causes of failure of children and young people from socially excluded localities in the process of informal education. Informal education is now perceived as a group, institutionalized, planned process that takes place outside or out of the formal education curriculum, ie, in free, "optional" or after-school time. To determine the causes of failure of children and youth in the formal education process, the chosen method of individual interviews. The research sample consisted of five clients open club. People in Need in Bilina, who have failed or are failing in the process of informal learning in institutionalized facilities. In conclusion there are recommendations for working with this client segment. Keywords: Rom, ethnic minority, socially excluded, socially excluded localities, community, neformal education