• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1103
  • 351
  • 333
  • 127
  • 88
  • 64
  • 46
  • 32
  • 24
  • 20
  • 12
  • 12
  • 11
  • 9
  • 8
  • Tagged with
  • 2811
  • 330
  • 278
  • 246
  • 235
  • 222
  • 188
  • 173
  • 169
  • 144
  • 127
  • 124
  • 122
  • 122
  • 121
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
381

Contribuições à modelagem de teletráfego fractal. / Contribution to the modeling of fractal teletrffic

Lima, Alexandre Barbosa de 28 February 2008 (has links)
Estudos empíricos [1],[2] demonstraram que o trafego das redes Internet Protocol (IP) possui propriedades fractais tais como impulsividade, auto-similaridade e dependência de longa duração em diversas escalas de agregação temporal, na faixa de milissegundos a minutos. Essas características tem motivado o desenvolvimento de novos modelos fractais de teletráfego e de novos algoritmos de controle de trafego em redes convergentes. Este trabalho propõe um novo modelo de trafego no espaço de estados baseado numa aproximação finito-dimensional do processo AutoRegressive Fractionally Integrated Moving Average (ARFIMA). A modelagem por meio de processos auto-regressivos (AR) também é investigada. A analise estatística de series simuladas e de series reais de trafego mostra que a aplicação de modelos AR de ordem alta em esquemas de previsão de teletráfego é fortemente prejudicada pelo problema da identificação da ordem do modelo. Também demonstra-se que a modelagem da memória longa pode ser obtida as custas do posicionamento de um ou mais pólos nas proximidades do circulo de raio unitário. Portanto, a implementação do modelo AR ajustado pode ser instável devido a efeitos de quantização dos coeficientes do filtro digital. O modelo de memória longa proposto oferece as seguintes vantagens: a) possibilidade de implementação pratica, pois não requer memória infinita, b) modelagem (explícita) da região das baixas freqüências do espectro e c) viabilização da utilização do filtro de Kalman. O estudo de caso apresentado demonstra que é possível aplicar o modelo de memória longa proposto em trechos estacionários de sinais de teletráfego fractal. Os resultados obtidos mostram que a dinâmica do parâmetro de Hurst de sinais de teletráfego pode ser bastante lenta na pratica. Sendo assim, o novo modelo proposto é adequado para esquemas de previsão de trafego, tais como Controle de Admissão de Conexões (CAC) e alocação dinâmica de banda, dado que o parâmetro de Hurst pode ser estimado em tempo real por meio da aplicação da transformada wavelet discreta (Discrete Wavelet Transform (DWT)). / Empirical studies [1],[2] demonstrated that heterogeneous IP traffic has fractal properties such as impulsiveness, self-similarity, and long-range dependence over several time scales, from miliseconds to minutes. These features have motivated the development of new traffic models and traffic control algorithms. This work presents a new state-space model for teletraffic which is based on a finite-dimensional representation of the ARFIMA random process. The modeling via AutoRegressive (AR) processes is also investigated. The statistical analysis of simulated time series and real traffic traces show that the application of high-order AR models in schemes of teletraffic prediction can be highly impaired by the model identification problem. It is also demonstrated that the modeling of the long memory can be obtained at the cost of positioning one or more poles near the unit circle. Therefore, the implementation of the adjusted AR model can be unstable due to the quantization of the digital filter coefficients. The proposed long memory model has the following advantages: a) possibility of practical implementation, inasmuch it does not require infinite memory, b) explicit modeling of the low frequency region of the power spectrum, and c) forecasts can be performed via the Kalman predictor. The presented case study suggests one can apply the proposed model in periods where stationarity can be safely assumed. The results indicate that the dynamics of the Hurst parameter can be very slow in practice. Hence, the new proposed model is suitable for teletraffic prediction schemes, such as CAC and dynamic bandwidth allocation, given that the Hurst parameter can be estimated on-line via DWT.
382

O gênero Paepalanthus Mart. (Eriocaulaceae) no Parque Estadual do Biribiri, Diamantina, Minas Gerais / The genus Paepalanthus Mart. (Eriocaulaceae) at Biribiri State Park, Diamantina, Minas Gerais.

Andrino, Caroline Oliveira 20 September 2013 (has links)
O gênero Paepalanthus (Eriocaulaceae) conta atualmente com cerca de 400 espécies, distribuídas principalmente nas Américas Central e do Sul, com centro de diversidade localizado na Cadeia do Espinhaço, em Minas Gerais e Bahia. É o gênero de Eriocaulaceae mais complexo do ponto de vista taxonômico e a carência de estudos floristicos dificulta o aprimoramento de sua circunscrição. Nesse contexto, foi efetuado o levantamento de Paepalanthus do Parque Estadual do Biribiri, que está inserido no Planalto de Diamantina, Minas Gerais, (18°00\' - 18°15\'S, 43°30\' - 43°40\'W). O gênero está representado no Parque por 33 espécies. São apresentadas chaves de identificação para os gêneros de Eriocaulaceae e para as espécies de Paepalanthus ocorrentes na área de estudo, descrições e ilustrações, bem como comentários sobre morfologia, habitat, distribuição geográfica e fenologia / The genus Paepalanthus Mart. comprises ca. 400 species, mainly distributed in South and Central America, with center of diversity located in the Espinaço Range, in Minas Gerais and Bahia. In a taxonomic view, Paepalanthus is the most complex genus of Eriocaulaceae and the lack of floristic studies hinders the improvement of its species circumscription. In this context, it was carried out the Paepalanthus flora of Biribiri State Park, which is located in Diamantina Plateau, in Minas Gerais, (18°00\' - 18°15\'S; 43°30\' - 43°40\'W). In the area, the genus is represented by 33 species. Identification keys to Eriocaulaceae genera and Paepalanthus species ocurring in the study area, descriptions and illustrations, as well as comments about morphology, habitat, geographic distribution and phenology are provided
383

Sistemática: estudos em Asclepiadoideae (Apocynaceae) da Cadeia do Espinhaço de Minas Gerais. / Systematics: studies on Asclepiadoideae (Apocynaceae) from the Espinhaco Range of Minas Gerais, Brazil.

Rapini, Alessandro 13 December 2000 (has links)
Asclepiadoideae está entre os táxons mais promissores para o desenvolvimento de estudos em sistemática vegetal. Pensando nisso, foi elaborado o projeto "Asclepiadoideae (Apocynaceae) da Cadeia do Espinhaço de Minas Gerais". A tese conta com seis capítulos-satélites independentes (capítulos I-IV e VI-VII) relacionados ao tema central (capítulo V). Os capítulos são manuscritos submetidos para publicação e estão de acordo com os padrões de cada revista. I. O Paradoxo da Sistemática II. Apocynaceae III. Asclepiadaceae ou Asclepiadoideae? Conceitos Distintos de Agrupamento Taxonômico IV. Estudos Taxonômicos em Asclepiadoideae (Apocynaceae) do Novo Mundo V. Asclepiadoideae (Apocynaceae) da Cadeia do Espinhaço de Minas Gerais, Brasil VI. Cadeia do Espinhaço, Minas Gerais, Brasil. Asclepiadoideae (Apocynaceae) VII. Riqueza e Endemismo de Asclepiadoideae (Apocynaceae) na Cadeia do Espinhaço de Minas Gerais, Brasil – Uma Visão Conservacioniosta O capítulo I aborda a equivalência entre unidades evolutivas e taxonômicas, apresentando algumas colocações sobre conceitos básicos em sistemática. O capítulo II sintetiza em um trabalho de divulgação o conhecimento atual sobre Apocynaceae, com ênfase para as plantas americanas. O capítulo III explica a inclusão de Asclepiadaceae como subfamília (Asclepiadoideae) de Apocynaceae, procurando desmistificar a importância dos resultados cladísticos e moleculares nessa classificação. O capítulo IV discute a artificialidade dos gêneros americanos de Asclepiadoideae (em especial aqueles representados no Espinhaço), justificando algumas novidades taxonômicas propostas. O tratamento das Asclepiadoideae da Cadeia do Espinhaço de Minas Gerais (99 espécies e 20 gêneros) é apresentado no capítulo V e vem acompanhado de um guia de campo (capítulo VI). O capítulo VII demonstra a disparidade no esforço de coleta ao longo do Espinhaço de Minas Gerais, fornecendo uma avaliação preliminar sobre o conhecimento da flora do Espinhaço e sua possível influência na conservação da biodiversidade dessa região.
384

Fósseis em micritos quaternários da Serra da Bodoquena, Bonito-MS e sua aplicação em estudos paleoambientais / Fossils in quaternary micrites of Bodoquena Range, Bonito-MS and their application in paleoenvironmental studies

Utida, Giselle 22 May 2009 (has links)
O município de Bonito e arredores em Mato Grosso do Sul apresentam atrações turísticas relacionadas a diversos tipos de depósitos carbonáticos quaternários, que formam cachoeiras, barragens naturais e tornam as águas de turbidez quase nula. A área está inserida no Parque Nacional da Serra da Bodoquena e na Reserva da Biosfera do Pantanal (UNESCO). As tufas calcárias são rochas porosas formadas pela precipitação do carbonato de cálcio em água doce e podem conter diversos tipos de fósseis. Apresentam-se sob a forma de cachoeiras, barragens e sedimentos lacustres que formam depósitos micríticos inconsolidados, descritos dentro da Formação Xaraiés. Os micritos são extensos e relativamente espessos em toda a região. Contudo, a maior parte das ocorrências está intemperizada, parcialmente erodida e distribuída em áreas limitadas. O presente estudo foca a caracterização paleontológica, granulométrica e geoquímica (elementos maiores, menores, traços e isótopos de carbono e oxigênio), através de levantamento de detalhe dos micritos da área da Mineração Calcário Xaraés, em Bonito (MS). As amostras foram obtidas por furo de trado, coleta de amostras superficiais e de bloco decimétrico orientado para estudo tafonômico, complementado com investigação de campo e amostragem de algumas áreas na Serra da Bodoquena, Pantanal e Corumbá. Os micritos da Mineração Calcário Xaraés, são depósitos lacustres e podem ser descritos em três eventos: 1: base afossilífera, oncólitos, argilominerais e dados isotópicos marcam um período de maior umidade; 2: ostracodes, algas caráceas e gastrópodes fósseis que colonizaram este estágio e a baixa variação dos dados isotópicos sugerem um período estável; 3: gastrópodes de água doce resistentes a ressecamento colonizaram esta etapa, em associação com os dados isotópicos sugerem processos alternados de evaporação e umidade. O topo da seção estudada é marcada por evaporação total da água do lago, morte em massa do gastrópode Biomphalaria e instalação do gastrópode Idiopyrgus. A ausência de estruturas sedimentares, orientação, seleção e fragmentação dos bioclastos e o empacotamento fraco a disperso e feições de alteração dos bioclastos por tempo de exposição na interface água-sedimento denotam condições estáticas do ambiente durante o processo final de deposição. Estas características também sugerem abastecimento do lago por águas subterrâneas, pois produzem menor taxa de alteração dos bioclastos e manutenção das condições químicas da água, como demonstrado pela homogeneidade dos dados geoquímicos. Outros depósitos estudados de micritos também apresentam resultados semelhantes. Há forte presença de indivíduos do gênero Biomphalaria e da Família Hydrobiidae nos depósitos. Dados de campo mostram os depósitos de tufas calcárias na região com extensão maior que as registradas, ocorrendo principalmente próximos aos leitos dos rios atuais, que os dissolvem nos períodos chuvosos. Os depósitos de tufas calcárias da Serra da Bodoquena, principalmente os micríticos, provavelmente foram formados nos últimos 10.000 anos, indicando período mais quente e seco que o atual. Os últimos 2.700 na região podem ser caracterizados por aumento da umidade, extinção dos depósitos micríticos e instalação dos depósitos de tufas de cachoeira e barragens. / Bonito town and surrounding areas in Mato Grosso do Sul state are tourist attractions related with many quaternary carbonate deposits which form waterfalls, dams and render almost zero turbidity waters. That area is part of the National Park of Bodoquena Range and Pantanal Biosphere Reserve (UNESCO). Calcareous tufa are porous rocks formed by calcium carbonate laid down in freshwaters containg a great variety of fossils. They were presented in form of waterfalls, dams and lacustrine sediments, forming unconsolidated micritic deposits, being part of the Xaraés Formation. Micritic deposits are extensive and thick in whole area. Most of the deposits are weathered, partly eroded and distributed in restricted areas. The present study focuses on paleontological, granulometric, and geochemical (major, minor and trace elements, carbon and oxygen isotopes) data. The micritic deposits of Calcário Xaraés Mine in Bonito (MS) are detailed studied. Samples were obtained by auger drilling, also in outcrops area and one orientated centimetric indeformed block for taphomic study. The research was complemented with field study and sampling in the Bodoquena Range, Pantanal and Corumbá. Calcário Xaraés Mine micrites are lacustrine deposits. We described through three events: 1: their base does not contain fossils, but bears oncoids, clayminerals. Isotope data point to a wetter period, 2: ostracods, charophytes and gastropods fossils colonized this episode and homogeneity of isotope data suggest a stable event, 3: freshwater gastropods endured scarce water conditions so colonized the area. The isotope data then was varied suggesting alternated periods of evaporation and humidity. Total water lake evaporation resulted in the mass death of the Biomphalaria gastropod and consequent with diffusion of Idiopyrgus gastropod. Absence of sedimentary structures, bioclastic orientation, selection and fragmentation, weak to dispersal packing bioclast and bioclastic alteration features, are indications of long durantion in the water-sediment interface. These features suggest environmental static conditions during the final deposition. These features also suggest groundwater supplies to the lake, leading to less bioclastic alteration, and maintaing chemical water conditions, such as homogeneity of geochemical data. Other studied micritic deposits show almost the same results. There is strong presence of gastropod Biomphalaria and Hydrobiidae Family on these deposits. Field data show calcareous tufa deposits with an extension larger than the studied area, occurring mainly next to the rivers, which dissolve micritic in the rainy period. Bodoquena Range calcareous tufa deposits, mainly micritic sediments, probably were formed in the last 10.000 years, indicating a hotter and drier period than nowadays. The last 2.700 years in this region can be characterized by humidity increase, micritic deposits extinctions and installation of waterfalls and dams tufa depositions.
385

O papel da reação em cadeia da polimerase (PCR) de largo espectro no diagnóstico etiológico da sepse / The role of broad-range polymerase chain reaction (PCR) in the etiologic diagnosis of sepsis

Gozzi, Aline 01 August 2014 (has links)
A sepse é responsável por uma alta taxa de internação hospitalar e morbimortalidade. Devido à gravidade do quadro clínico e às limitações dos métodos tradicionais para identificação e isolamento bacteriano, é recomendado o início empírico de antimicrobiano(s) de largo espectro. O desenvolvimento da biologia molecular, particularmente da reação em cadeia da polimerase (PCR), tornou possível o diagnóstico rápido de agentes infecciosos. Entretanto, devido à diversidade dos possíveis agentes etiológicos na sepse, a utilização da PCR com primers específicos para cada agente se torna pouco prática. Com a PCR de largo espectro é possível que em uma só reação se identifique qualquer bactéria, possibilitando um tratamento precoce e direcionado. Desta forma, este trabalho teve como objetivo avaliar o papel da PCR de largo espectro no diagnóstico etiológico de pacientes com sepse e a comparação desta técnica com os métodos tradicionais de cultura. Foram incluídos 74 pacientes com diagnóstico de sepse atendidos na Unidade de Emergência do Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto USP e 14 voluntários sadios. Foi realizada a extração do DNA do soro, plasma e buffy-coat dos pacientes, seguida da realização da PCR de largo espectro com dois diferentes pares de primers, e sequenciamento das amostras positivas. Dos 74 pacientes, 39 (53%) eram homens; a média de idade foi 55 ± 19 anos; 37 (50%) tiveram sepse grave e 37 (50%) choque séptico; e a mortalidade foi 51%. A maioria das infecções primárias teve origem respiratória (66%), seguida de infecções gênito-urinárias (20%). A hemocultura foi positiva em 22 (30%) pacientes, e sua positividade foi significativamente maior em pacientes mais velhos (p< 0,05) e com valores mais altos de proteína C reativa (CRP) (p< 0,05). A PCR de largo espectro foi positiva em 44 (59%) pacientes considerando os dois pares de primers, sendo sua positividade significativamente maior que a da hemocultura (p< 0,001). Para o par Bak11W/Bak2 ela foi positiva em 25 (34%) pacientes, e para o par Taf/Tar, em 29 (39%) pacientes. Em relação às frações do sangue, amostras de 24 pacientes foram positivas na fração soro; 22 na fração plasma; e 18 na fração buffy-coat. Nenhuma característica clínica ou demográfica dos pacientes influenciou a positividade da PCR de largo espectro. A PCR de largo espectro foi negativa em todas as frações do sangue dos voluntários sadios. A sensibilidade, especificidade, valor preditivo positivo e valor preditivo negativo da PCR foram 59%, 100%, 100% e 32%, respectivamente. Em 40 (54%) pacientes os resultados da PCR e hemocultura foram concordantes. O coeficiente de concordância kappa obtido foi 0,147 (p = 0,131). Em relação ao sequenciamento, em 21 amostras de 16 pacientes foi possível identificar um agente etiológico. As bactérias mais detectadas foram Escherichia coli (3), Enterococcus sp. (2), Staphylococcus sp. (2) e Ralstonia sp. (2). Em apenas dois pacientes as amostras tiveram a mesma espécie bacteriana detectada na hemocultura e PCR de largo espectro (E. coli e Streptococcus pneumoniae). Em resumo, a PCR de largo espectro foi mais sensível do que a hemocultura na identificação bacteriana em pacientes com sepse atendidos em um Hospital de Emergência / Sepsis is responsible for a high rate of hospitalization and mortality. Due to the severity of clinical presentation and limitation of traditional methods for bacterial identification and isolation, it is recommended to initiate empirically broad-spectrum antimicrobial treatment. The development of molecular biology, particularly the polymerase chain reaction (PCR), enabled to realize a rapid diagnosis of infectious agents. However, due to the diversity of possible etiologic agents in sepsis, the use of PCR with specific primers for each agent becomes impractical. With the broad-range PCR, it is possible, in a single reaction, to identify any bacteria, allowing an early and directed treatment. Thus, this study aimed to evaluate the role of broad-range PCR in the etiologic diagnosis of patients with sepsis and compare this technique with traditional methods of culture. Seventy-four patients with sepsis admitted to the Emergency Unit of Clinical Hospital of Ribeirão Preto Medical School USP and 14 controls were included in the study. DNA from serum, plasma and buffy-coat were extracted from all patients and controls. Broad-range PCR was performed in all samples, followed by DNA sequencing of the amplicons. Out of 74 patients, 39 (53%) were male, mean age was 55 ± 19 years old; 37 (50%) patients had severe sepsis and 37 (50%) septic shock; the mortality rate was 51%. Most of primary infections were from respiratory tract (66%), followed by urinary tract infection (20%). Blood culture was positive in 22 (30%) patients, and its positivity was greater in older patients (p< 0,05) and patients with higher levels of C reactive protein (CRP) (p< 0,05). Broad-range PCR was positive in 44 (59%) patients, when considering both pairs of primers, and was significantly increased compared to blood culture positivity (p< 0,001). Broad-range PCR using Bak11W/Bak2 primers was positive in 25 (34%) patients, and using Taf/Tar primers, in 29 (39%) patients. Related to blood fractions, samples from 24 patients were positive in serum; 22 in plasma fraction; and 18 in buffy-coat. None of clinical and demographic characteristics influenced the broad-range PCR positivity. The sensitivity, specificity, positive predicted value and negative predictive value, when considered healthy persons as negative control, were 59%, 100%, 100% and 32%, respectively. In 40 (54%) patients, blood culture and PCR results were concordant. The concordance coefficient kappa obtained was 0,147 (p = 0,131). Regarding to etiologic agents, in 21 samples, from 16 patients, a bacteria was identified by sequencing. The most common bacteria were Escherichia coli (3), Enterococcus sp. (2), Staphylococcus sp. (2) and Ralstonia sp. (2). In only two patients, the same bacterial species were identified in both, blood culture and broad-range PCR (E. coli e Streptococcus pneumoniae). In conclusion, broad-range PCR was more sensitive than blood culture for bacterial identification in septic patients admitted to an Emergency Unit
386

Improvement of the in-cycle speed fluctuation and system efficiency of an auxiliary power unit

Liu, Dian January 2016 (has links)
Well reported problems around air quality and climate change, together with the energy crisis resulting from finite fossil fuel resources is motivating all the automotive manufacturers to develop new propulsion systems through electrification and hybridisation. The range extended electric vehicle (REEV) is one of these solutions that seeks a practical compromise between the on-board battery size and the one-charge driving range. The auxiliary power unit (APU) is the key component in a REEV and is designed to maintain the battery charge for long distance trips. Since the APU does not propel the vehicle, it only requires a small capacity engine with low-cylinder-count. This type of engine exhibits severe speed fluctuations due to its low firing frequency. As the engine and the M/G are isolated from the vehicle driving wheels, it is possible to use the electric machine to deliver a counteracting torque to the engine reducing the resultant torque spikes and thus the system speed oscillation but likely to increase the electric losses. This research work aims to minimise the speed fluctuation balanced against the extra losses introduced. A Dynamic Torque Control (DTC) strategy was designed and tested on an APU using a novel approach to achieve this target. The system components were modelled individually regarding to the prototype system specifications, which is developed within a collaborative R&D project. The empirical engine model was calibrated with extensive bench testing data to recreate the in-cycle torque waveforms. The motor/generator was modelled as a novel hybrid between an analytical model and an FEA model which allowed the winding inductance variation due to the current rise to be included in the model. This approach was designed to replicate the electric machine performance with high fidelity whilst keeping the computational time and cost low. With the help from the system model, the DTC torque demand patterns were designed based on detailed analysis of the contribution factors of the speed fluctuation and the electric machine losses. A unique Pareto Curve of the speed fluctuation reduction and the electrical loss was identified during the analysis and allowed the optimal demand pattern to be developed for a given torque capability electric machine. The simulation results showed that the system in-cycle speed fluctuations could be reduced by 16.4% and 19.11% at 2000rpm full load and 4500rpm full load condition respectively while the electric specific fuel consumption (ESFC) rose by 2.26% and 1.35% at the same operation points. The DTC strategy was implemented in the prototype APU and successfully tested on the rig at 2000rpm and 4500rpm. A reduction in the speed oscillation and the ESFC increase consistent with the simulation results were observed. The simulation estimates on ESFC was proved within an error of 2.19%. This research improves the insight into the mechanisms that are responsible for increased losses when dynamic torque control is used and develops an optimisation approach which takes account of these factors. When an electric machine, which does not have the same instantaneous peak torque capability as the engine, is used in an APU, a better compromise between speed fluctuation smoothing and system efficiency can be achieved.
387

The role of the NS segment of Influenza A virus in setting host range and pathogenicity

Turnbull, Matthew Luke January 2017 (has links)
Influenza A virus (IAV) circulates in waterfowl, causing mostly asymptomatic infections. IAV can undergo host adaptation and evolve to cause significant disease and mortality in domestic poultry and mammals, applying an enormous socio-economic burden on society. Sporadically, IAV causes global pandemics in man due to its zoonotic nature, and this can result in millions of deaths worldwide during a single outbreak. Host adaptation of IAV is an incompletely understood phenomenon, but is known to involve both host and viral determinants. It is essential to improve the understanding of the factors governing host range and pathogenicity of avian IAV, especially given the absence of a universal influenza vaccine and a limited weaponry of effective antiviral compounds. This study set out to improve the understanding of host adaptation of avian IAV, focussing on segment 8 (NS segment) of the virus genome. The NS segment of non-chiropteran IAV circulates as two phylogenetically distinct clades – the ‘A-’ and ‘B-alleles’. The A-allele is found in avian and mammalian viruses, but the B-allele is considered to be almost exclusively avian. This might result from one or both of the major NS gene products (NS1 and NEP) being non-functional in mammalian host cells, or from an inability of segment 8 RNA to package into mammalian-adapted strains. To investigate this, the NS segments from a panel of avian A- and B-allele strains were introduced into human H1N1 and H3N2 viruses by reverse genetics. A- and B-allele reassortant viruses replicated equally well in a variety of mammalian cell types in vitro. Surprisingly, the consensus B-allele segment 8 out-competed an A-allele counterpart when reassortant H1N1 viruses were co-infected, with the parental WT segment 8 being most fit in this system. A- and B-allele NS1 proteins were equally efficient at blocking the mammalian IFN response both in the context of viral infection and in transfection-based reporter assays. Consensus A- and B-allele H1N1 viruses also caused disease in mice and replicated to high virus titre in the lung. Interestingly, the B-allele virus induced more weight-loss than the A-allele, although the parental WT virus was most pathogenic in vivo. To re-address the hypothesis that B-allele NS genes really are avian-restricted, the relative rates of independent Aves to Mammalia incursion events of A- and B-allele lineage IAV strains was estimated and compared using phylogenetic analyses of all publically available segment 8 sequences. 32 A-allele introduction events were estimated compared to 6 B-allele incursions, however the total number of avian Aallele sequences outnumbered B-allele sequences by over 3.5 to 1, and the relative rates of introduction were not significantly different across the two lineages suggesting no bias against avian B-allele NS segments entering mammalian hosts in nature. Therefore, this study provides evidence that avian B-allele NS genes are not attenuating in mammalian hosts and are able to cause severe disease. Thus, this lineage of IAV genes, previously assumed to be avian-restricted, should be considered when assessing zoonotic potential and pandemic risk of circulating avian IAVs.
388

Estudos em Chamaecrista (Leguminosae) do Planalto de Diamantina, Minas Gerais: flora e novidades taxonômicas / Studies in Chamaecrista (Leguminosae) of Diamantina Plateau, Minas Gerais: flora and taxonomic novelties

Cota, Matheus Martins Teixeira 11 July 2016 (has links)
Floras são importantes no contexto moderno da biodiversidade, pois além de gerar informações iniciais para diversos estudos, promovem a melhor compreensão da diversidade de uma área. A crescente perda de habitats no bioma Cerrado, que inclui os campos rupestres e é um dos seis &ldquo;hotspots&rdquo; mundiais, alerta para a importância de estudos nesse bioma. A família Leguminosae possui alta representatividade nos campos rupestres e Chamaecrista é um de seus gêneros com grande número de espécies, muitas endêmicas. O gênero possui cerca de 330 espécies e duas características marcantes são as anteras pubescentes ao longo das suturas e nectários extraflorais. Apesar da grande importância das Leguminosas, estudos taxonômicos com essa família ainda são incipientes na região do Planalto de Diamantina. O presente trabalho teve como principal objetivo o estudo taxonômico das espécies de Chamaecrista do Planalto de Diamantina, Minas Gerais. O trabalho baseou-se no levantamento das espécies nos principais herbários com coleções do Planalto de Diamantina, em consultas bibliográficas e atividades de campo. Em sua forma final, a dissertação é dividida em dois capítulos, um referente à flora e outro referente à descrição de uma espécie nova. Neles, constam descrições das espécies, chave de identificação, mapas de distribuição geográfica, comentários taxonômicos e ilustrações / Floras are important in the modern context of biodiversity, as well as generating initial information to several studies, promoting better understanding of the diversity of an area. The increasing loss of habitats in the Cerrado biome, which includes the rocky fields and is one of six &ldquo;hotspots&rdquo; worldwide, highlights the importance of studies in this biome. Leguminosae has high representation in rock fields and Chamaecrista is one of its genera with great number of species, many endemic. The genus has about 330 species and two striking features are the anthers pubescent along the sutures and extrafloral nectaries. Despite the great importance of Leguminosae, taxonomic studies of this family are still incipient in the Diamantina Plateau region. This study aimed to the taxonomic study of the species of Chamaecrista the Diamantina Plateau, Minas Gerais state. The work was based on the survey of the species in the main herbaria with collections from Diamantina Plateau, bibliographic consultations and field activities. In its final form, the dissertation is divided into two chapters, one relating to the flora and the other concerning the description of a new species. There are descriptions of species, key to species, geographic distribution maps, taxonomic comments and illustrations
389

A study of the balance of shoulder agonist and antagonist muscle during concentric and eccentric action: a quantifiable isokinetic assessment of the strength ratio.

January 1996 (has links)
by Choi Man. / Year shown on spine: 1997. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves 146-153). / Abstract --- p.1 / Chapter 1 --- Introduction --- p.3 / Chapter 1.1 --- Anatomy --- p.4 / Chapter 1.2 --- Kinematics of the overhead sports --- p.6 / Chapter 1.3 --- Isokinetics assessment of the shoulder rotators --- p.8 / Chapter 1.4 --- Objectives of the study --- p.10 / Chapter 1.5 --- Method of investigation --- p.11 / Chapter 1.5.1 --- Subject --- p.12 / Chapter 1.5.2 --- Equipment --- p.13 / Chapter 1.5.3 --- Protocol --- p.14 / Chapter 1.6 --- Data Management --- p.17 / Chapter 1.7 --- Clinical application --- p.18 / Chapter 1.8 --- Definition of terms --- p.18 / Chapter 2 --- Literture Review --- p.20 / Chapter 2.1 --- Anatomy --- p.20 / Chapter 2.1.1 --- Ligament --- p.21 / Chapter 2.1.2 --- Muscles --- p.24 / Chapter 2.2 --- Biomechanics of the overhead movement --- p.30 / Chapter 2.2.1 --- Wind up Phase --- p.32 / Chapter 2.2.2 --- Cocking Phase --- p.33 / Chapter 2.2.3 --- Acceleration Phase --- p.36 / Chapter 2.2.4 --- Deceleration Phase --- p.38 / Chapter 2.3 --- Eccentric contraction --- p.40 / Chapter 2.3.1 --- Physiology of eccentric contraction --- p.40 / Chapter 2.3.2 --- Mechanical trauma in eccentric contraction & DOMS --- p.41 / Chapter 2.3.3 --- Eccentric contraction in Plyometric --- p.43 / Chapter 2.3.4 --- Role of eccentric contraction in overhead sports --- p.44 / Chapter 2.3.5 --- Comparison with concentric contraction --- p.45 / Chapter 2.4 --- Isokinetics --- p.46 / Chapter 2.4.1 --- Introduction to isokinetics --- p.46 / Chapter 2.4.2 --- Reliability of isokinetic assessment on Shoulder rotator --- p.48 / Chapter 2.4.3 --- Agonist / Antagonist Ratio --- p.51 / Chapter 2.4.4 --- Variation of torques with testing protocols --- p.52 / Chapter 2.4.5 --- Comparison of muscle torques in different groups --- p.56 / Chapter 2.4.6 --- Isokinetic eccentric contraction of shoulder Rotators --- p.62 / Chapter 3 --- Method of Investigation --- p.63 / Chapter 3.1 --- Subject --- p.64 / Chapter 3.1.1 --- Part One --- p.64 / Chapter 3.1.2 --- Part Two --- p.65 / Chapter 3.1.3 --- Criteria of subject recruitment --- p.65 / Chapter 3.2 --- Equipment --- p.66 / Chapter 3.2.1 --- Collection of medical history and general informations --- p.66 / Chapter 3.2.2 --- Test for general laxity --- p.66 / Chapter 3.2.3 --- Test for shoulder impingement --- p.72 / Chapter 3.2.4 --- Test for shoulder instability --- p.73 / Chapter 3.2.5 --- Joint range measurement --- p.76 / Chapter 3.2.6 --- Isokinetic strength of shoulder rotators --- p.78 / Chapter 3.3 --- Calibration --- p.79 / Chapter 3.4 --- Testing procedure --- p.79 / Chapter 3.4.1 --- "Explanation,warning & consent" --- p.79 / Chapter 3.4.2 --- Warming up --- p.80 / Chapter 3.4.3 --- Screening --- p.81 / Chapter 3.4.4 --- Isokinetic testing of the rotational strength of both shoulders --- p.81 / Chapter 3.5 --- Operator --- p.87 / Chapter 3.6 --- Data Management --- p.88 / Chapter 3.6.1 --- Part One --- p.88 / Chapter 3.6.2 --- Part Two --- p.89 / Chapter 4 --- Result --- p.91 / Chapter 4.1 --- Part One --- p.89 / Chapter 4.1.1 --- Intra-class correlation coefficient --- p.90 / Chapter 4.1.2 --- Correlation between the PTR & the ASMSTR --- p.92 / Chapter 4.2 --- Part Two --- p.94 / Chapter 4.2.1 --- Comparison between the Members in the Hong Kong Badminton Team with the Non-athlete Subjects --- p.94 / Chapter 4.2.2 --- Comparison between the Badminton Players in the Hong Kong Team and the Hong Kong National Junior Team --- p.105 / Chapter 5 --- Discussion --- p.111 / Chapter 5.1 --- General discussion of the design of the study --- p.111 / Chapter 5.1.1 --- Subject --- p.111 / Chapter 5.1.2 --- Specific test --- p.112 / Chapter 5.1.3 --- Warming up --- p.112 / Chapter 5.1.4 --- Testing protocol --- p.113 / Chapter 5.2 --- Part One --- p.116 / Chapter 5.2.1 --- Test-retest reliability --- p.117 / Chapter 5.2.2 --- Correlation between the PTR and the ASMSTR --- p.120 / Chapter 5.3 --- Part two --- p.122 / Chapter 5.3.1 --- Comparison between the HKT and the non- athletes --- p.123 / Chapter 5.3.2 --- Presentation of torque ratio in the HKJ --- p.133 / Chapter 5.3.3 --- Performance in those with history of shoulder problem --- p.134 / Chapter 5.4 --- Clinical application and suggestion for further study --- p.139 / Chapter 6 --- Conclusion --- p.144 / Chapter 7 --- Reference --- p.146 / Chapter 8 --- Appendix
390

Load-balanced Range Query Workload Partitioning for Compressed Spatial Hierarchical Bitmap (cSHB) Indexes

January 2018 (has links)
abstract: The spatial databases are used to store geometric objects such as points, lines, polygons. Querying such complex spatial objects becomes a challenging task. Index structures are used to improve the lookup performance of the stored objects in the databases, but traditional index structures cannot perform well in case of spatial databases. A significant amount of research is made to ingest, index and query the spatial objects based on different types of spatial queries, such as range, nearest neighbor, and join queries. Compressed Spatial Bitmap Index (cSHB) structure is one such example of indexing and querying approach that supports spatial range query workloads (set of queries). cSHB indexes and many other approaches lack parallel computation. The massive amount of spatial data requires a lot of computation and traditional methods are insufficient to address these issues. Other existing parallel processing approaches lack in load-balancing of parallel tasks which leads to resource overloading bottlenecks. In this thesis, I propose novel spatial partitioning techniques, Max Containment Clustering and Max Containment Clustering with Separation, to create load-balanced partitions of a range query workload. Each partition takes a similar amount of time to process the spatial queries and reduces the response latency by minimizing the disk access cost and optimizing the bitmap operations. The partitions created are processed in parallel using cSHB indexes. The proposed techniques utilize the block-based organization of bitmaps in the cSHB index and improve the performance of the cSHB index for processing a range query workload. / Dissertation/Thesis / Masters Thesis Computer Science 2018

Page generated in 0.0417 seconds