O Arquipélago de São Pedro e São Paulo (ASPSP) localiza-se cerca de 1100 km do litoral do Rio Grande do Norte, e está constituído por quatro ilhas maiores dispostas em semicírculo formando uma enseada com profundidades que variam ente 3 a 18 m. Vários estudos sobre a fauna existente no ASPSP foram realizados, entretanto, este é apenas o segundo trabalho com foco na ostracofauna do arquipélago. No material analisado, coletado na enseada, foram reconhecidas 14 espécies, dez gêneros e oito famílias; dentre estes, foi descrito um gênero e espécie novos para a família Hemicytheridae e uma nova espécie para o gênero Keijcyoidea. Dez espécies foram deixadas em nomenclatura aberta, sendo muito provável a existência de outras espécies novas, já que o ASPSP é uma área muito distante tanto de outras ilhas oceânicas quanto de continentes. Aspectos ecológicos e zoogeográficos complementam o estudo da riqueza específica da fauna aqui analisada. Loxocorniculum tricornatum Krutak possui a maior abundância, perfazendo um total de 4214 espécimens (1150 coletados vivos). Keijcyoidea sp. nov. A (539 espécimens, sendo 153 vivos) e Xestoleberis sp. 2 (179 indivíduos, dos quais 69 vivos) ocupam o segundo e o terceiro lugar em abundância, respectivamente. As espécies L. tricornatum e Triebelina sertata Triebel, esta última um ostracode cosmopolita tropical, ocorrem no Brasil não somente no ASPSP, mas também no Atol das Rocas e nas regiões de águas quentes da plataforma continental brasileira; T. sertata é também registrada na Ilha da Trindade. Curiosamente, espécies pandêmicas de mares rasos e quentes, como Kangarina abyssicola (Mueller), Kotoracythere incospicua Brady, Keijia demissa Teeter, Neomonoceratina mediterranea (Ruggieri) e Tenedocythere ex. gr. transoceanica Teeter, não foram registrados no ASPSP. / The Archipelago of São Pedro and São Paulo (ASPSP), located about 1,100 km of the coast of the Rio Grande do Norte State, consists of four major islands arranged in a semicircle forming a cove with depths between three and 18 m. Many studies on the archipelago fauna were performed, however, this is only the second one focusing its ostracode fauna. In the study material, 14 species, ten genera and eight families were identified, including a new genus and species of Hemicytheridae, and a new species of Keijcyoidea. Ten species were left in open nomenclature, and the existence of other new ones is very probable, since the ASPSP is very distant from both other oceanic islands and continents. Ecological and zoogeographical remarks complement this faunal study. Loxocorniculum tricornatum Krutak possesses the greatest abundance, with a total of 4214 specimens (1150 collected alive). Keijcyoidea sp. nov. A (539 specimens, being 153 alive) and Xestoleberis sp. 2 (179 individuals, being 69 alive) occupy the second and third place in abundance, respectively. The species L. tricornatum and Triebelina sertata Triebel, the latter a tropical cosmopolitan ostracode, occur in Brazil not only in the ASPSP, but also in the Rocas Atoll and in the region of warm waters of the Brazilian continental shelf; T. sertata is also recorded around the Trindade Island. Surprisingly, pandemic species of shallow and warm seas, as Kangarina abyssicola (Mueller), Kotoracythere incospicua Brady, Keijia demissa Teeter, Neomonoceratina mediterranea (Ruggieri) and Tenedocythere ex. gr. transoceanica Teeter, were not found in ASPSP.

Desde que os vírus de computadores tornaram-se um grave problema para sistemas individuais e corporativos, diversos modelos de disseminação de vírus têm sido usados para explicar o comportamento dinâmico da propagação desse agente infeccioso. Como estratégias de prevenção de proliferação de vírus, o uso de antivírus e sistema de vacinação, têm contribuído para a contenção da proliferação da infecção. Outra forma de combater os vírus é estabelecer políticas de prevenção baseadas nas operações dos sistemas, que podem ser propostas com o uso de modelos populacionais, como os usados em estudos epidemiológicos. Entre os diversos trabalhos, que consideram o clássico modelo epidemiológico de Kermack e Mckendrick, SIR (suscetível - infectado - removido), aplicado ao contexto de propagação de vírus, a introdução de computadores antidotais, como programa antivírus, fornece muitos resultados operacionais satisfatórios. Neste trabalho, o modelo SIRA (suscetível - infectado - removido - antidotal) é estudado considerando a taxa de mortalidade como parâmetro e associado a isso, o parâmetro que recupera os nós infectados é variado de acordo com a alteração da taxa de mortalidade. Nessas condições, a existência dos pontos de equilíbrio livre de infecção são encontrados, mostrando que o modelo é robusto. / Since computer viruses have become a serious problem for individual and corporate systems, several models of virus dissemination have been used to explain the dynamic behavior of the spread of this infectious agent. As prevention strategies for virus proliferation, the use of antivirus and vaccination system, have contributed to contain the proliferation of the infection. Another way to combat viruses is to establish prevention policies based on the operations of the systems, which can be proposed with the use of population models, such as those used in epidemiological studies. Among the several papers, which consider the classic epidemiological model of Kermack and Mckendrick, SIR (susceptible - infected - removed), applied to the context of virus propagation, the introduction of antidotal computers, such as antivirus program, provides many satisfactory operational results. In this work, the SIRA (susceptible - infected - removed - antidotal) model is studied considering the mortality rate as a parameter and associated with this, the parameter that recovers infected nodes is varied according to the change in mortality rate. Under these conditions, the existence of infection free equilibrium points are found, showing that the model is robust.

Doctorat en Sciences / info:eu-repo/semantics/nonPublished

>Magister Scientiae - MSc / HIV/AIDS is nowadays considered as the greatest public health disaster of modern time. Its progression has challenged the global population for decades. Through mathematical modelling, researchers have studied different interventions on the HIV pandemic, such as treatment, education, condom use, etc. Our research focuses on different compartmental models with emphasis on the effect of public health education. From the point of view of statistics, it is well known how the public health educational programs contribute towards the reduction of the spread of HIV/AIDS epidemic. Many models have been studied towards understanding the dynamics of the HIV/AIDS epidemic. The impact of ARV treatment have been observed and analysed by many researchers. Our research studies and investigates a compartmental model of HIV with treatment and education campaign. We study the existence of equilibrium points and their stability. Original contributions of this dissertation are the modifications on the model of Cai et al. [1], which enables us to use optimal control theory to identify optimal roll-out of strategies to control the HIV/AIDS. Furthermore, we introduce randomness into the model and we study the almost sure exponential stability of the disease free equilibrium. The randomness is regarded as environmental perturbations in the system. Another contribution is the global stability analysis on the model of Nyabadza et al. in [3]. The stability thresholds are compared for the HIV/AIDS in the absence of any intervention to assess the possible community benefit of public health educational campaigns. We illustrate the results by way simulation The following papers form the basis of much of the content of this dissertation, [1 ] L. Cai, Xuezhi Li, Mini Ghosh, Boazhu Guo. Stability analysis of an HIV/AIDS epidemic model with treatment, 229 (2009) 313-323. [2 ] C.P. Bhunu, S. Mushayabasa, H. Kojouharov, J.M. Tchuenche. Mathematical Analysis of an HIV/AIDS Model: Impact of Educational Programs and Abstinence in Sub-Saharan Africa. J Math Model Algor 10 (2011),31-55. [3 ] F. Nyabadza, C. Chiyaka, Z. Mukandavire, S.D. Hove-Musekwa. Analysis of an HIV/AIDS model with public-health information campaigns and individual with-drawal. Journal of Biological Systems, 18, 2 (2010) 357-375. Through this dissertation the author has contributed to two manuscripts [4] and [5], which are currently under review towards publication in journals, [4 ] G. Abiodun, S. Maku Vyambwera, N. Marcus, K. Okosun, P. Witbooi. Control and sensitivity of an HIV model with public health education (under submission). [5 ] P.Witbooi, M. Nsuami, S. Maku Vyambwera. Stability of a stochastic model of HIV population dynamics (under submission).

The nutritional value of indigenous fodder plants has been reported to be high and constant throughout seasons as compared to grasses. The aim of this study was to evaluate the nutritional value of three tree species of the Combretum family, C. apiculatum, C. molle, C. zeyheri, and two other plant species, Colophospermum mopane and Pelthophorum africanum. This would be achieved through the determination of chemical composition (ash, dry matter (DM), organic matter (OM), CP, acid detergent fibre (ADF), acid detergent lignin (ADL), acid detergent indigestible nitrogen (ADIN), condensed tannins (CT) and ether extract (EE)), rumen degradability and in vitro digestibility of the leaves of these species were determined. The foliage of the tree species were collected in and north of Pretoria. After rinsing a portion of each species' samples, they were freeze-dried, prepared for analyses and stored as fresh samples pending analyses. The in situ analysis was done as blanket analysis over all the seasonal samples of each plant species excluding Mopane. This was done because the leaf materials collected were not enough to conduct a complete trial for each seasonal collection. Therefore sites were not considered for statistical analyses hence species were compared across seasons only. All the plant species exhibited a wider range of the chemical fractions. Their ash concentrations ranged from 30.3 g/kg DM for C. zeyheri to 85.8 g/kg DM forC. molle, NDF 270.3 g/kg DM for C. apiculatum to 410.1 g/kg DM for P africanum, ADF 208.1 g/kg DM P. africanum to 375.2 g/kg DM for C. molle. Their CP ranged from 62.9 g/kg DM for C. molle to 172 g/kg DM for Mopane, CT 65.6 mg sorghum tannin equivalent (STE)/g DM for C. zeyheri to 660.3 mg STE/g DM for Mopane, ADIN ranged from 1.2 g/kg DM for C. apiculatum to 3.3 g/kg DM in C. mopane. The range of some mineral concentrations of all the plants was not as wide as the other fractions. The concentrations of Ca ranged from 7.9 g/kg DM for Mopane to 16 g/kg DM for C. molle, K 1.2 g/kg DM Mopane to 7.8 g/kg DM for C. molle, Mg 1.4 g/kg DM for C. molle to 3.8 g/kg DM for C. apiculatum. The concentrations of Cu ranged from 7.8 mg/kg DM for C. molle to 66 mg/kg DM for C apiculatum, Fe 169 mg/kg DM for Mopane to 435 mg/kg DM for C. zeyheri. The in vitro dry matter digestibility (IVDOM) ranged from 52.6% for Mopane and C. zeyheri to 64.1% for C. apiculatum. The in situ degradability fractions for the Combretum species ranged as follows: soluble fraction was 4.02% for C. apiculatum to 25.4% for C. zeyheri; degradable fraction was 34% for C. zeyheri to 44% for C. apiculatum and the extent of nitrogen (N) degradation was 47% for C. apiculatum to 60% for C. zeyheri. The concentrations of the chemical fractions of all the plants did not show a particular seasonal trend. However significant and insignificant variations were observed. The CP concentrations were almost constant implying a better N supply to animals throughout the seasons. The CT concentrations were not high enough to adversely affect the digestibility of protein. The Combretum species showed reasonable N degradability in situ, C. zeyheri the most degradable. The plant's digestibility values were within the range of browse plants. These results cannot be conclusive on the eventual nutritional value of these plants to the animals. Further studies would be necessary to quantify the availability of the chemical fractions and the foliage's palatability to the animals. / Dissertation (M Inst. Agrar (Animal Production))--University of Pretoria, 2005. / Animal and Wildlife Sciences / unrestricted

The Carlina vulgaris complex in central Europe includes several lineages defined by their ecology, morphology and distribution. This diploma thesis is focused on relationships between the taxa recognized in the Czech Republic, namely Carlina vulgaris subsp. vulgaris, C. biebersteinii subsp. biebersteinii, C. biebersteinii subsp. brevibracteata and C. biebersteinii subsp. sudetica. Molecular analysis revealed two genetically defined groups. One includes samples from relict populations in western Bohemia and from high mountains classified as C. biebersteinii subsp. biebersteinii and C. biebersteinii subsp. sudetica. The other is represented by plants classified as C. vulgaris and C. biebersteinii subsp. brevibracteata. This genetic differentiation was also confirmed by morphometric analysis. However, relationships within these two groups remain unclear. The Czech populations of Carlina biebersteinii subsp. biebersteinii as well as of C. biebersteinii subsp. sudetica are closely related to the mountain populations in the Alps and Carpathians. Their occurrence in the Czech Republic is relict and they should be in focus of nature conservation. However, the separate taxonomic position of the claimed endemic C. biebersteinii subsp. sudetica is probably unjustified.

The development of genetic tools to study populations at the molecular level has been one of the most important contributions to understand demographic processes in wild populations of conservation concern. Habitat loss and habitat fragmentation are the main factors causing declines of birds populations, as in the case of the Worthen’s sparrow (Spizella wortheni), a Mexican endemic Emberizid restricted to scrub and grassland habitats in northeastern Mexico. Here, I present the first molecular tools developed specifically for the study of S. wortheni populations. Genetic analyses of seven remnant populations of S. wortheni showed that no genetic impoverishment is present. This unexpected result may be caused by the nomadic life style of S. wortheni, which makes it tolerant to habitat modification. The high levels of inbreeding I found can be attributed to the tendency of S. wortheni to move in gregarious groups, since non-random mating might be present. My analyses based on the study of DNA segments from five mitochondrial genes support the hypotheses that S. wortheni and S. pusilla (Field Sparrow), as well as S. breweri (Brewer’s Sparrow) and S. passerina (Chipping Sparrow) are sister taxa. A phylogenetic network analysis showed that conflicting relationships among Spizella species might be caused by possible hybridization events between ancestors of extant taxa. Based on the study of the phylogenetic community structure, patterns of phylogenetic attraction and repulsion, and on the estimation of marginality, specialization and niche overlap among species, I investigated the possible causes of rarity in S. wortheni. The phylogenetic community structure analysis suggested that Spizella species are clustered across vegetation communities. Assuming phylogenetically conserved ecological traits, the phylogenetically clumped distribution may indicate habitat filtering among Spizella species. Additionally, behavioral traits such as flocking in mixed-species flocks might contribute to explain the pattern of community structure I found, and suggest that the rarity of S. wortheni is not a matter of interspecific competition. According to the phylogeny, evolutionary age was also discarded as a cause of rarity of this species. Compared with its congenerics, S. wortheni is the most specialized of all Spizella species. A potential evolutionary change of S. wortheni behavior that results in niche specialization is more likely to be the cause of its rarity.

This study examines the legitimation of power and knowledge in the struggle of public health and health care agencies in the Lower Congo region of the Democratic Republic of Congo to vanquish chronic tropical diseases. Of particular interest is the creation of alternative institutions following the collapse of state sponsored structures and supply lines in the 1980s and 1990s, and the process by which such alternative structures are legitimized. A review of legitimation theory suggests that new paradigms are required to assess the nature and efficacy of diverse non-state institutions within a fluid global neo-liberal context. The paper argues that these new or newly adapted post-state institutional arrangements, born in the crisis of state failure, may be effective in the lessening of the disease burden that weighs on the region to the extent that they are able to muster the legitimacy of the populace, the professions, the national society, and the wider international community. I thus hope to shed light on the paradox of persistent tropical diseases — e. g., malaria, sleeping sickness, and schistosomiasis, as well as seasonal grippe, typhoid fever, tuberculosis and HIV/AIDS — as endemic or seasonal scourges, despite their being understood by local specialists, with known treatments and public health measures to control them.

With over 800,000 dams occurring globally and the construction of thousands more being proposed, successful restoration of regulated rivers will depend on the creation of broadly applicable frameworks that provide management solutions by generalizing patterns in habitat and ecology. Based on the prevailing scientific literature, restoring natural stream flows in disturbed rivers is dependent upon developing quantitative, transferable stream flow-ecology relationships. The purpose of my dissertation was to apply a framework to regulated and unregulated streams within an eight-state region of the southeastern US to test its ability to generalize patterns in natural and altered stream flow and develop flow-ecology relationships. I created a simplified, 5-step version of the Ecological Limits of Hydrologic Alteration (ELOHA) framework (Poff et al. 2010). I carried out each of the steps in sequential order for unregulated and dam-regulated streams found in my region. The steps of my restoration framework are as follows: 1. Develop a natural flow classification of unregulated streams 2. Develop a tool that uses landscape characteristics to predict flow class membership 3. Use the predictive tool or pre-disturbance hydrologic information to classify regulated rivers to natural flow classes 4. Based on class membership, generalize patterns in hydrologic alteration 5. Relate ecological patterns to patterns in hydrologic alteration in relation tomorphology, temperature, and landscape disturbance Altogether, the results of steps 1-4 suggest that patterns in natural flow dynamics and hydrologic alterations can successfully be placed within a framework and generalized to provide the basis and context for environmental flow management; however, results of step 5 suggest that patterns in flow alteration were poorly related to fish assemblages relative to channel morphology, habitat fragmentation, temperature, and substrate. Thus, the development of patterns in hydrologic alteration using the existing frameworks (including mine) may not be ecologically-relevant. My results suggest that current regulated river restoration should not be dependent upon the development of flow-ecology relationships alone, but the interaction between flow, morphology, and temperature within a landscape disturbance context. These relationships should be incorporated within a hierarchical framework to guide restoration efforts in regulated rivers in the future. / Ph. D.

A batata-da-serra, Ipomoea serrana Sim.-Bianch. & L.V. Vasconcelos, é uma liana endêmica da Chapada Diamantina, Bahia, cuja raiz tuberosa e consumida por populações humanas ha muitos anos. Apesar da espécie, classificada como vulnerável pela IUCN (União Internacional para a Conservação da Natureza), estar submetida à pressão antrópica devido à exploração de raízes tuberosas, para uso na alimentação, são raros os estudos com a espécie, razão pela qual e de grande importância conhecer a diversidade e estrutura genética da espécie. Estudos sobre diversidade e estrutura genética a partir de marcadores moleculares são importantes por fornecerem dados sobre impactos da exploração antrópica sobre as populações, podendo oferecer subsídio para planos de manejo e conservação de espécie. Cinco populações da Chapada Diamantina, constituindo um total de 142 indivíduos, foram investigados com quatro iniciadores Inter Simple Sequence Repeats (ISSR), resultando em 34 bandas, das quais 25 foram polimórficas. A analise dos parâmetros genéticos mostrou que as populações apresentam variabilidade moderada, com 73,8% de bandas polimórficas, 0,264 de índice de diversidade de Nei e 0,389 de índice de Shannon (valores médios). A maior parte da variação ocorreu dentro das populações (77%), estimado pela analise de variância molecular (AMOVA), enquanto que a variação entre populações foi de 23%, o que corroborou os resultados de estruturação obtidos pelo programa Structure, analise de coordenadas principais (PCoA) e agrupamento estimado pelo método Neighbor-Joining, a partir do coeficiente de dissimilaridade de Jaccard. A analise Bayesiana separou os indivíduos em quatro grupos, sendo que as populações Andaraí e Capão foram alocadas em grupos distintos, enquanto as outras três populações compartilharam indivíduos distribuídos em outros dois grupos. Este estudo, por seu caráter pioneiro com relação aos marcadores moleculares, constituiu o primeiro passo para o conhecimento da diversidade genética da espécie. Estudos futuros poderão ampliar o conhecimento sobre a espécie podendo oferecer subsidio para a elaboração de um plano de manejo para esta espécie que tem sido explorada na região. / batata-da-serra, Ipomoea serrana Sim.-Bianchi. & L.V. Vasconcelos, is an endemic liana from the Chapada Diamantina, Bahia, whose tuberous roots have been consumed by human populations for many years. Although the species, classified as vulnerable by the IUCN (International Union for Conservation of Nature), is subject to anthropic pressure due to the exploration of tuberous roots for food consumption, few studies have been conducted on the species, which is why it is of great importance to know the diversity and genetic structure of the species. Studies on genetic diversity and structure with molecular markers are important for providing data on the impacts of anthropogenic exploitation and can be useful for the species management and conservation. Five populations of Chapada Diamantina, consisting a total of 142 individuals were studied with four ISSR primers, resulting in 34 bands, 25 of which were polymorphic. The genetic diversity analysis showed that populations have a moderate variability, with 73.8% of polymorphic bands, Nei\'s unbiased gene diversity (He) was 0.264; Shannon diversity index (I) was 0.389, average values. Most of the variation was within populations (77%), as estimated by the analysis of molecular variance (AMOVA), whereas the variation between populations was 23% of the total, which corroborated the results of program Structure, principal co-ordinate analysis (PcoA) and cluster analyses, using the Neighbor-Joining method, and the dissimilarity coefficient of Jaccard. The Bayesian analysis separated the individuals into four groups, with populations Andarai and Capao allocated into different groups, while the other three populations shared individuals in two other groups. Considering the pioneering characteristic of this study at the molecular level, it represents the first step towards the knowledge on the genetic diversity of the species. Future studies will increase the knowledge on the genetics of the species and may provide subsidy for the development of a management plan for a species that has been explored in the region.