The sea louse (Lepeophtheirus salmonis), whose larvae are planktonic and disseminated in the water column, is an economically important parasite of Atlantic salmon (Salmo Salar). The effect of temperature (5, 10, 15°C), diet (larvae alone, larvae plus phytoplankton), and bivalve size (small, medium, large) on the amount of L. salmonis larvae ingested by various species of filter-feeding bivalves (Pacific oysters, Pacific scallops, blue/Gallo’s mussel hybrids, basket cockles) was examined in a series of laboratory experiments. Four separate temperature/diet experiments were conducted (one for each species) in which large bivalves were individually placed in 2-L containers holding 750 ml of aerated, filtered seawater and fed one of three treatment diets: (1) phytoplankton: ~7.1 x 104 cells ml-1 of Isochrysis sp. (Tahitian strain, TISO); (2) sea lice larvae: ~431 larvae (mostly nauplii); and (3) phytoplankton and larvae (at the levels mentioned above). There was also a control treatment of phytoplankton and larvae, but no bivalve. After feeding for 1 h, the bivalve soft tissues were excised and preserved, the digestive system was dissected, and sea lice larvae were removed and counted to provide direct evidence of ingestion. The larvae remaining free swimming in the container were iv preserved and counted. The proportion missing from the container was used to estimate ingested larvae in statistical analyses. Two additional experiments investigating the effect of bivalve size (small, medium, large) on the ingestion of sea lice larvae were conducted with Pacific oysters and Pacific scallops. The heights for oysters (anterior-posterior axes) were 19.2, 44.2, and 84.0 mm, and scallops (dorsal hinges to ventral margins) were 40.3, 64.1, 102.7 mm. The methodology for the size experiments was as previously described for the temperature/diet experiments with the following changes: (1) the diet of larvae alone was not used; (2) the mean number of larvae in each container was ~498; (3) the mean concentration of TISO added to each container was ~7.8 x104 cells ml-1, and (4) the mean water temperature was 10.4°C. The data for the four temperature/diet experiments indicate that all four bivalve species ingested sea lice larvae, whether their diet included phytoplankton or not, and that temperature had no significant effect. The data for the two size experiments indicated that all three sizes of oysters and scallops ingested sea lice larvae and that there was a significant size effect. Large shellfish consumed a significantly greater proportion of the sea lice larvae than the small shellfish. Bivalves grown at salmon net pens as part of an IMTA (Integrated Multi-Trophic Aquaculture) system may be able to reduce the number of sea lice larvae as well as being an additional crop of market value. Future research, conducted at a commercial scale at a salmon farm, is warranted in order to determine if bivalves can serve in this role. / Graduate

Title from title page of PDF (University of Missouri--St. Louis, viewed March 23, 2010). Includes bibliographical references.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-03-09T23:28:00Z No. of bitstreams: 1 LeonardoRuanDantasDeAguiar_DISSERT.pdf: 2449402 bytes, checksum: b04f8afa2c8b58e8060f6cec86cbf7ab (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-03-11T23:16:07Z (GMT) No. of bitstreams: 1 LeonardoRuanDantasDeAguiar_DISSERT.pdf: 2449402 bytes, checksum: b04f8afa2c8b58e8060f6cec86cbf7ab (MD5) / Made available in DSpace on 2016-03-11T23:16:07Z (GMT). No. of bitstreams: 1 LeonardoRuanDantasDeAguiar_DISSERT.pdf: 2449402 bytes, checksum: b04f8afa2c8b58e8060f6cec86cbf7ab (MD5) Previous issue date: 2015-04-30 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq / As funda??es de apoio constituem um dos tipos de pessoas jur?dicas de direito privado forjadas com a finalidade de dar apoio a projetos de pesquisa, ensino e extens?o e de desenvolvimento institucional, cient?fico e tecnol?gico brasileiro. Observadas como elos das rela??es entre universidade, empresa e governo, as funda??es de apoio emergem no cen?rio brasileiro a partir do pleito de estabelecer uma plataforma de desenvolvimento econ?mico baseada no trip?: ci?ncia, tecnologia e inova??o - CT&I. Em termos aplicados, essas operam como ferramentas de desburocratiza??o, tornando a gest?o dos entes p?blicos mais ?gil, sobretudo ? gest?o acad?mica em conformidade a abordagem da Tr?plice H?lice. Em face do exposto o presente estudo tem como objetivo compreender como as rela??es da Tr?plice H?lice interv?m no processo de capta??o de recursos das funda??es de apoio brasileiras. Para compreens?o das rela??es postas, utilizou-se os modelos de intera??o Universidade-Empresa-Governo preconizadas por S?bato e Botana (1968), a abordagem da Tr?plice H?lice disposta por Etzkowitz e Leydesdorff (2000), assim como a perspectiva dos sistemas nacionais de inova??o, discutida por Freeman (1987, 1995), Nelson (1990, 1993), e Lundvall (1992). O objeto de pesquisa deste estudo consta das 26 funda??es estaduais de amparo ? pesquisa associadas ao Conselho Nacional das Funda??es Estaduais de Amparo ? Pesquisa ? CONFAP, assim como as 102 funda??es de apoio ?s IES associadas ao Conselho Nacional das Funda??es de Apoio ?s Institui??es de Ensino Superior e de Pesquisa Cient?fica e Tecnol?gica ? CONFIES, totalizando 128 entidades. Como estrat?gia de pesquisa, este estudo se caracteriza como uma pesquisa aplicada, de abordagem quantitativa. Os dados prim?rios desta pesquisa foram coletados com o uso do procedimento e-mail Survey. Foram coletadas 75 observa??es, que correspondem ? 58,59% do universo de pesquisa. Cabe ponderar o uso do m?todo bootstrap com vistas a validar o uso da amostra nas an?lises de resultados. Para a an?lise dos dados foram utilizadas t?cnicas de estat?stica descritiva e de an?lises multivariadas de dados: a an?lise de conglomerados; a correla??o can?nica e a regress?o log?stica bin?ria. A partir das ra?zes can?nicas obtidas, os resultados indicaram que a rela??o de depend?ncia entre as vari?veis de rela??es (com os atores da Tr?plice H?lice) e os recursos financeiros investidos em projetos de inova??o ? baixa, admitindo a hip?tese nula deste estudo, que as rela??es da Tr?plice H?lice n?o t?m interferido positivamente ou negativamente na capta??o de recursos para investimentos em projetos de inova??o. Por outro lado, os resultados obtidos com a an?lise de conglomerados apontam que as entidades que possuem maiores quantitativos e montantes financeiros de projetos constam em sua maioria de funda??es de grande porte (mais de 100 funcion?rios), que apoiam at? cinco IES, publicam relat?rios de gest?o e utilizam em sua estrutura de capital, maior financiamento do setor p?blico. Por fim, ? pertinente destacar que o poder de classifica??o do modelo log?stico obtido neste estudo demonstrou alta capacidade preditiva (80,0%) facultando ? comunidade acad?mica replica??es em ambientes de an?lise similares. / Foundations support constitute one of the types of legal entities of private law forged with the purpose of supporting research projects, education and extension and institutional, scientific and technological development of Brazil. Observed as links of the relationship between company, university, and government, foundations supporting emerge in the Brazilian scene from the principle to establish an economic platform of development based on three pillars: science, technology and innovation ? ST&I. In applied terms, these ones operate as tools of debureaucratisation making the management between public entities more agile, especially in the academic management in accordance with the approach of Triple Helix. From the exposed, the present study has as purpose understanding how the relation of Triple Helix intervenes in the fund-raising process of Brazilian foundations support. To understand the relations submitted, it was used the interaction models University-Company-Government recommended by S?bato and Botana (1968), the approach of the Triple Helix proposed by Etzkowitz and Leydesdorff (2000), as well as the perspective of the national innovation systems discussed by Freeman (1987, 1995), Nelson (1990, 1993) and Lundvall (1992). The research object of this study consists of 26 state foundations that support research associated with the National Council of the State Foundations of Supporting Research - CONFAP, as well as the 102 foundations in support of IES associated with the National Council of Foundations of Support for Institutions of Higher Education and Scientific and Technological Research ? CONFIES, totaling 128 entities. As a research strategy, this study is considered as an applied research with a quantitative approach. Primary research data were collected using the e-mail Survey procedure. Seventy-five observations were collected, which corresponds to 58.59% of the research universe. It is considering the use of the bootstrap method in order to validate the use of the sample in the analysis of results. For data analysis, it was used descriptive statistics and multivariate data analysis techniques: the cluster analysis; the canonical correlation and the binary logistic regression. From the obtained canonical roots, the results indicated that the dependency relationship between the variables of relations (with the actors of the Triple Helix) and the financial resources invested in innovation projects is low, assuming the null hypothesis of this study, that the relations of the Triple Helix do not have interfered positively or negatively in raising funds for investments in innovation projects. On the other hand, the results obtained with the cluster analysis indicate that entities which have greater quantitative and financial amounts of projects are mostly large foundations (over 100 employees), which support up to five IES, publish management reports and use in their capital structure, greater financing of the public department. Finally, it is pertinent to note that the power of the classification of the logistic model obtained in this study showed high predictive capacity (80.0%) providing to the academic community replication in environments of similar analysis.

Made available in DSpace on 2014-08-20T14:31:32Z (GMT). No. of bitstreams: 1 dissertacao_tatiana_cheuiche_pesenti.pdf: 10915320 bytes, checksum: 8c48924716b7a42d6df3f382d58c13bc (MD5) Previous issue date: 2008-03-28 / Ostrich is an ratit bird that originated from Africa. In Brazil is found manly in commercial farms. The number of farms that raise ostriches is growing in Brazil due to the great reproductive potential of these birds and the great economic value of its products. Because of this increase in raising of ostriches, parasites have appeared of which little is known or studied, thus raising the need for study and description of these parasites to the scientific community and breeders. With the objective of studying the presence of parasitess in ostriches from commercial farms in the Rio Grande do Sul State, heads, respiratory and digestive systems were examined individually from 34 ostriches as well as a collection of their feathers. The material was collected during the slaughter in the Castilhense Abattoir, located in the city of Julio de Castilhos, RS. The contents and mucous membrane of the small intestine, cecum and large intestine were examined; as well as the mucous of the esophagus, proventriculus and gizzer; lung, trachea and pancreas were examined; as well as the exterior, oral, nasal and ocular cavities of the head. Nematodes were found in the digestive and respiratory systems and lice and mites in feathers. The nematodes were clarified with lactophenol and identified as Libyostrongylus douglassii, L. dentatus and Codiostomum struthionis. The lice were clarified using metil salicilate, the mites with lactophenol and identified respectively as Struthiolipeurus rheae and Struthiopterolichus sculpturatus. This is the first description of C. struthionis in ostriches in the Rio Grande do Sul state and L. dentatus in Brazil, as well as the simultaneous parasitism of L. douglassii and L. dentatus in the same host in these country. This is also the first report of S. rheae and S. sculpturatus in ostriches from the Rio Grande do Sul state. / Avestruz é uma ave ratita originária da África. No Brasil é encontrada, principalmente, em criatórios comerciais, os quais vem se expandindo no país devido ao alto potencial reprodutivo destas aves, bem como pelo valor econômico de seus produtos. Devido a esse aumento na criação comercial tem ocorrido a detecção de parasitos pouco conhecidos ou estudados, havendo a necessidade de descrição desses à comunidade científica e aos criadores, pois podem causar um impacto negativo no plantel. Com o objetivo de pesquisar parasitos em avestruz de criatórios comerciais do RS, examinaram-se individualmente as cabeças e os sistemas digestório e respiratório de 34 aves, bem como, coletivamente, suas plumas. O material foi coletado durante o abate no frigorífico Castilhense localizado no município de Júlio de Castilhos, RS. Os conteúdos e as mucosas do intestino delgado, ceco e intestino grosso; mucosas do pró-ventrículo, moela e esôfago; pulmão, traquéia e pâncreas foram examinados, além da superfície externa da cabeça bem como as cavidades oral, nasal e ocular. Encontraram-se nematóides no sistema digestório e piolhos e ácaros nas plumas. Os nematóides encontrados foram clarificados em lactofenol e identificados como Libyostrongylus douglassii, L. dentatus e Codiostomum struthionis. Os piolhos foram clarificados em salicilato de metila, os ácaros em lactofenol e identificados, respectivamente, como Struthiolipeurus rheae e Struthiopterolichus sculpturatus. Faz-se o primeiro registro de C. struthionis em avestruz no RS e L. dentatus no Brasil, assim como o parasitismo simultâneo de L. douglassii e L. dentatus. Registra-se também a ocorrência de S. rheae e S. sculpturatus pela primeira vez em avestruz no Rio Grande do Sul.

Parasitic copepods including Lepeophtheirus salmonis have been the focus of strong concern for the health of wild and farmed salmonids in the Pacific and Atlantic Oceans. Salmon are highly valuable species from both socioeconomic and ecological perspectives. The host-parasite dynamics of Lepeophtheirus salmonis and the Atlantic and Pacific salmonids have changed over evolutionary time to the point that both Atlantic and Pacific salmon and Atlantic and Pacific Lepeophtheirus salmonis are genetically distinct. Recent human interference with the natural population dynamics of this parasite and its hosts may have altered the population genetic structure of Lepeophtheirus salmonis, particularly because salmon farms may provide more stable conditions for parasite population growth. High abundance of Lepeophtheirus salmonis on salmon farms causes damage to the farmed salmon and leads to increased infection intensities in nearby wild hosts. Some Atlantic Lepeophtheirus salmonis have developed resistance to the anti-parasitic drugs they are repeatedly exposed to. No drug resistance has yet been detected within the Pacific Ocean, where only one drug is available, and heavily relied on, to treat Lepeophtheirus salmonis infections. Control of Lepeophtheirus salmonis abundance on Pacific salmon farms is important to maintain the health of farmed salmon and is also important to protect wild salmonids from increased infections originating from salmon farms. The goal of this thesis was to characterize and employ a large suite of molecular markers to assess the population structure of Lepeophtheirus salmonis in the Pacific Ocean. Until this point, the primary focus of Lepeophtheirus salmonis population genetics research has been limited to the Atlantic Ocean and has relied on a small number of available molecular markers. Available expressed sequence tag DNA libraries were screened to identify putative polymorphic loci, which were then experimentally evaluated. We characterized 22 novel microsatellite loci and 87 single nucleotide polymorphisms within 25 nuclear loci for Lepeophtheirus salmonis. We used these genetic markers, as well as 5 microsatellite loci previously developed for use in Atlantic Lepeophtheirus salmonis population studies, to genotype 562 Lepeophtheirus salmonis that were collected from12 Pacific Ocean sampling locations. We compared Lepeophtheirus salmonis genotypes among: (1) seven wild host populations and five farmed host populations within the Pacific Ocean; (2) geographically separated wild host populations, ranging from the Bering Sea to the southwest end of Vancouver Island, British Columbia; and (3) temporally separated cohorts of farmed Atlantic salmon from two geographically distant farm locations on the northwest coast of Vancouver Island and the Campbell River area east of central Vancouver Island. Our analyses failed to resolve significant population structure among sampled Pacific Lepeophtheirus salmonis and, therefore, supports a hypothesis of high gene flow throughout the Northeast Pacific Ocean. It is important to understand the biology and population dynamics of Lepeophtheirus salmonis because it is a consequential parasite of wild and farmed salmonids in the Pacific Ocean. Both the molecular tools developed for this study and the population genetics information generated from this study have contributed to our overall understanding of the evolutionary history and population dynamics of Lepeophtheirus salmonis. / Graduate

Yesinia pestis est l'agent de la peste, maladie infectieuse spontanément mortelle, et une bactérie classée parmi les agents de bioterrorisme de groupe A [http://www.bt.cd.gov/agent/plague]. Les cas sporadiques ont été rapportés dans plusieurs pays d'Asie, d'Afrique, et d'Amérique et la peste reste endémique en Afrique (République Démocratique du Congo; Madagascar) qui déclare le plus grand nombre de cas annuels. La majorité de cas de peste chez les humains et les animaux sauvages se manifeste dans les régions délimitées géographiquement et appelées communément les foyers de la peste. Les mécanismes de la résistance de la peste dans le sol des foyers reste de nos jours un sujet de recherche alors que la peste est maintenant considérée comme une maladie re-émergente. Au cours de notre travail, nous avons développé un outil pour l'identification de Y. pestis par spectrométrie de masse MALDI-TOF MS. Cette méthode s'est avérée très simple et efficace pour l'identification au niveau des espèces, et constitue une méthode de première ligne d'identification. Nous avons ensuite montré que Y. pestis survivait et maintenait sa virulence pendant au moins neuf mois dans le sol stérilisé par la vapeur et humidifié, dépourvu d'éléments nutritifs ajoutés et d'invertébrés du sol. Afin de contribuer à l'étude de l'épidémiologie de la peste, nous avons démontré que seul le biovar Oriantalis est transmis dans un modèle animal par les poux d'homme (Pediculus humanus), les biovars Antiqua et Medievalis de Y. pestis n'étant pas transmissibles par les poux de corps. Le mécanisme impliqué dans la transmission de la peste par les poux de corps reste inconnu, ce qui voudrait dire que le mécanisme de l'adaptation de Y. pestis Orientalis à des nouveaux vecteurs qui sont corrélés aux circonstances de l'épidémie mortelle provoquée par la peste bubonique, reste aussi inconnu. Au cours d'un dernier travail, nous avons étudié des nouveaux composés pour la prophylaxie de la peste. Notamment, nous avons évalué le potentiel du lovastatine dans la prévention de la mortalité pendant la peste. Il a été démontré sur un modèle d'expérimentation avec les souris que la lovastatine réduisait considérablement le taux de mortalité associée à la peste. Toutes les données que nous avons rapportées dans ce rapport de thèse sont destinées à mieux comprendre le cycle épidémiologique de la peste. / Yersinia pestis is the agent of deadly plague and a bacterium listed in the group A of potential bioterrorism agents [http://www.bt.cdc.gov/agent/plague/]. Sporadic cases are reported in several countries in Asia, Africa and America. Majority of human plague cases and enzootic animals occur in the geographical areas of so-called plague foci. The mechanisms sustaining geographical foci of plague remain poorly understood and plague been classified as a currently re-emerging disease. As first step, we established new front line tool for Y. pestis identification by using MALDI-TOF MS. This method was demonstrated to be simple and effective for Y. pestis identification at species level. Second step, we demonstrated that Y. pestis survived fully virulent for at least 9 months in a steam sterilized, humidified soil devoid of any nutritional supplements or any soil invertebrates. In third step we successfully demonstrated that the human louse (Pediculus humanus) as vector of plague and the body lice transmission of plague was restricted to Orientalis biovar; Antiqua and Medievalis biovars of Y. pestis were not able to transmit by body lice. This result shows that a un- explained mechanism is involved in the body lice transmission of plague and Y. pestis Orientalis adaptation to newly described vectors which effectively correlates the mass death caused by bubonic plague in Black Death individuals. Finally we conclude our study by exploring new compounds for the plague prophylaxis. The potential role of lovastatin in the prevention of mortality during plague was assessed. Lovastatin could significantly reduce the mortality associated with plague in an experimental mouse model. All These data herein we reported in our study may help to better understanding the epidemiology of plague.

Salmon aquaculture can be a potential solution to bridge the gap between declining capture fisheries and increasing seafood demand. However, the environmental impacts it creates have generated criticism. The overall objectives of this dissertation are to examine the economic consequences of environmental issues associated with salmon aquaculture, and to explore policy implications and recommendations for reducing environmental impacts. These objectives are addressed in five main analyses. The growth of salmon aquaculture is analyzed based on farmed salmon production in the four leading producing countries and the sector as a whole. Analyses indicate that salmon aquaculture is unlikely to continue to grow at its current pace. A joint production function approach is used to estimate pollution abatement costs for the salmon aquaculture industry. Results reveal that pollution abatement costs vary among observations and models. On average, pollution abatement cost is estimated at 3.5% in terms of total farmed salmon production, and 6.5% in terms of total revenue of farmed salmon. The ecological and economic impacts of sea lice from salmon farms on wild salmon population and fisheries are also studied. Analyses suggest that these effects are minor when the sea lice induced mortality rate is below 20%, while they can be severe if the mortality is greater than 30%. Sea lice have greater ecological and economic impacts on pink salmon than on chum salmon. These effects are greater under a fixed exploitation rate than under a target escapement policy. The economic performance of open netcage and sea-bag production systems for salmon aquaculture is compared. Netcage systems appear to be more economically profitable than sea-bag systems when environmental costs are either not or only partially included. Sea-bag systems can be financially profitable only when the salmon they produce can achieve a price premium. Finally, policy implications are explored and recommendations are made for sustaining salmon aquaculture in a holistic manner based on the results from previous chapters. Technologies, economic-based instruments and more stringent environmental policies can be employed to reduce environmental impacts. However, there is no single solution to solve these environmental impacts, and a combination of policy options is needed. / Science, Faculty of / Resources, Environment and Sustainability (IRES), Institute for / Graduate

Vertebrate males frequently carry higher numbers of parasites than females. This bias in parasite loads could be a consequence of sexual selection. Grouping species are also assumed to be afflicted with larger numbers of parasites than solitary animals and associated costs of this parasitism could vary with group size or structure. I examined sex-biased parasitism and the influence of group size on parasite loads in Cape ground squirrels (Xerus inauris), a highly social species that occurs in the arid regions of southern Africa. Males carried three times as many ectoparasites as females, but females harbored nearly three times more endoparasites than males. Amount of time spent (per hour) autogrooming was similar between males and females, but amount time spent allogrooming by adult female was over eleven times that of adult males. Longer allogrooming of group members could be decreasing the numbers of ectoparasites of group members and ultimately the group. Males infrequently give or receive allogrooming and travel in very large home ranges, potentially increasing their exposure to ectoparasites. However, movement throughout a large home range may result in males foraging in areas with lower densities of fecal pellets, which could explain the lower endoparasite loads observed in males. When I considered the age class of group members, female age classes were similarly parasitized but male age classes were not. Sub-adult males carried similar ectoparasite loads to adult males and similar endoparasite loads to adult females. This result is of particular interest because sub-adult males are becoming scrotal but typically remain in the group until adulthood. Sexual selection does appear to influence parasite loads in this species, and parasite removal or avoidance potentially mitigates individual parasite loads and their associated costs. Parasites can be detrimental to the health, longevity, and reproduction of their hosts, but these costs are rarely quantified. I removed ectoparasites and endoparasites from Cape ground squirrels for three months and evaluated changes in female body mass, reproduction, burrow use, and grooming in response to parasite removal. Female body mass did not increase with parasite removal, but reproductive success (per capita offspring raised to emergence) increased nearly four-fold, while allogrooming by treated females decreased. Since breeding is highest in the late winter dry season when fewer resources are available, the impact of parasites may be highest during this season. Lactation and gestation are the most physiological stressful processes that females undergo, and the dramatic increase in reproductive success in treated females suggests that these females are able to allocate more resources to reproduction than females afflicted with parasites. These results suggest that studies investigating reproduction and fecundity must consider the vulnerability of the host to parasite infection and the potential impact on reproductive success.

No description available.

Made available in DSpace on 2015-03-03T15:16:23Z (GMT). No. of bitstreams: 1 LeonardoM.pdf: 1880413 bytes, checksum: c785ee7cbc933eb3ac782dc9ac382e6c (MD5) Previous issue date: 2009-12-18 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / We use a tight-binding formulation to investigate the transmissivity and the currentvoltage (I_V) characteristics of sequences of double-strand DNA molecules. In order to reveal the relevance of the underlying correlations in the nucleotides distribution, we compare theresults for the genomic DNA sequence with those of arti_cial sequences (the long-range correlated Fibonacci and RudinShapiro one) and a random sequence, which is a kind of prototype of a short-range correlated system. The random sequence is presented here with the same _rst neighbors pair correlations of the human DNA sequence. We found that the long-range character of the correlations is important to the transmissivity spectra, although the I_V curves seem to be mostly inuenced by the short-range correlations. We also analyze in this work the electronic and thermal properties along an _-helix sequence obtained from an _3 peptide which has the uni-dimensional sequence (Leu-Glu-Thr- Leu-Ala-Lys-Ala)3. An ab initio quantum chemical calculation procedure is used to obtain the highest occupied molecular orbital (HOMO) as well as their charge transfer integrals, when the _-helix sequence forms two di_erent variants with (the so-called 5Q variant) and without (the 7Q variant) _brous assemblies that can be observed by transmission electron microscopy. The di_erence between the two structures is that the 5Q (7Q) structure have Ala ! Gln substitution at the 5th (7th) position, respectively. We estimate theoretically the density of states as well as the electronic transmission spectra for the peptides using a tight-binding Hamiltonian model together with the Dyson's equation. Besides, we solve the time dependent Schrodinger equation to compute the spread of an initially localized wave-packet. We also compute the localization length in the _nite _-helix segment and the quantum especi_c heat. Keeping in mind that _brous protein can be associated with diseases, the important di_erences observed in the present vi electronic transport studies encourage us to suggest this method as a molecular diagnostic tool / Nesta tese, investigamos a transmissividade e as caracter?sticas de corrente como fun??o da diferen?a de potencial, no contexto da liga??o forte, em seq??ncias de dupla fita do DNA. Com o intuito de investigar a relev?ncia das correla??es subjacentes nas distribui??es dos nucleot?deos, comparamos os resultados de uma seq??ncia gen?mica do DNA com duas seq??ncias artificiais (Fibonacci e Rudin-Shapiro, que apresentam correla??o de longo alcance) e uma seq??ncia aleat?ria, prot?tipo de sistemas de correla??o de curto alcance. A seq??ncia aleat?ria utilizada apresenta a mesma correla??o de pares de primeiros vizinhos que a seq??ncia do DNA humano. Observamos que a caracter?stica de correla??o de longo alcance ? importante para o espectro de transmissividade, apesar das curvas IXV serem mais influenciadas por correla??es de curto alcance. Neste trabalho, analisamos tamb?m as propriedades t?rmicas e eletr?nicas de uma seq?encia α-h?lice, obtida de um pept?deo α3, o qual apresenta a seguinte seq??ncia unidimensional (Leu-Glu-Thr-Leu-Ala-Lys-Ala)3 (estrutura prim?ria). C?lculos ab initio qu?nticos s?o utilizados para obter as energias dos orbitais moleculares mais altos (HOMO, highest occupied molecular orbital), bem como suas integrais de transfer?ncias de cargas quando a seq??ncia α-h?lice forma uma estrutura fibrosa (variante 5Q) e n?o fibrosa (variante 7Q), as quais podem ser observadas atrav?s de microscopia eletr?nica de transmiss?o. A diferen?a entre as duas estruturas ? que a estrutura 5Q (7Q) apresenta a substitui??o Ala → Gln na 5a (7a) posi??o, respectivamente. N?s estimamos, teoricamente, a densidade de estado bem como o espectro de transmiss?o eletr?nico dos pept?deos, utilizando um Hamiltoniano no formalismo da liga??o-forte juntamente com a equa??o de Dyson. Al?m disso, n?s resolvemos a equa??o de Schr?dinger dependente do tempo para obter o espalhamento de um pacote de onda inicialmente localizado. N?s calculamos tamb?m o comprimento de localiza??o e, por fim, o calor espec?fico qu?ntico. Vale lembrar que a forma??o de prote?nas fibrosas podem estar associadas ? doen?as, de forma que as importantes diferen?as observadas no estudo das propriedades eletr?nicas de transporte nos encorajam a sugerir este m?todo como uma ferramenta de diagn?stico molecular