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Vector within-host feeding preference mediates transmission of a heterogeneously distributed pathogen

DAUGHERTY, Matthew P.; LOPES, Joao; ALMEIDA, Rodrigo P. P.
Fonte: WILEY-BLACKWELL Publicador: WILEY-BLACKWELL
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.28%
2. We documented the within-host distribution of two vector species that differ in transmission efficiency, the leafhoppers Draeculacephala minerva and Graphocephala atropunctata, and which are free to move throughout entirely caged alfalfa plants. The more efficient vector D. minerva fed preferentially at the base of the plant near the soil surface, whereas the less efficient G. atropunctata preferred overwhelming the top of the plant. 3. Next we documented X. fastidiosa heterogeneity in mechanically inoculated plants. Infection rates were up to 50% higher and mean bacterial population densities were 100-fold higher near the plant base than at the top or in the taproot. 4. Finally, we estimated transmission efficiency of the two leafhoppers when they were confined at either the base or top of inoculated alfalfa plants. Both vectors were inefficient when confined at the top of infected plants and were 20-60% more efficient when confined at the plant base. 5. These results show that vector transmission efficiency is determined by the interaction between leafhopper within-plant feeding behaviour and pathogen within-plant distribution. Fine-scale vector and pathogen overlap is likely to be a requirement generally for efficient transmission of vector-borne pathogens.; USDA; California Department of Food and Agriculture; CAPES/Brazil

Interactive Vector Field Feature Identification

II, Joel Daniels; ANDERSON, Erik W.; NONATO, Luis Gustavo; SILVA, Claudio T.
Fonte: IEEE COMPUTER SOC Publicador: IEEE COMPUTER SOC
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.28%
We introduce a flexible technique for interactive exploration of vector field data through classification derived from user-specified feature templates. Our method is founded on the observation that, while similar features within the vector field may be spatially disparate, they share similar neighborhood characteristics. Users generate feature-based visualizations by interactively highlighting well-accepted and domain specific representative feature points. Feature exploration begins with the computation of attributes that describe the neighborhood of each sample within the input vector field. Compilation of these attributes forms a representation of the vector field samples in the attribute space. We project the attribute points onto the canonical 2D plane to enable interactive exploration of the vector field using a painting interface. The projection encodes the similarities between vector field points within the distances computed between their associated attribute points. The proposed method is performed at interactive rates for enhanced user experience and is completely flexible as showcased by the simultaneous identification of diverse feature types.; Fapesp-Brazil[2008/03349-6]; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); CNPq-NSF[491034/2008-3]; U.S. National Science Foundation (NSF); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); NSF[IIS-0905385]; U.S. National Science Foundation (NSF); U.S. National Science Foundation (NSF); NSF[IIS-0844546]; NSF[CNS-0855167]; U.S. National Science Foundation (NSF); NSF[IIS-0746500]; U.S. National Science Foundation (NSF); NSF[ATM-0835821]; U.S. National Science Foundation (NSF); U.S. National Science Foundation (NSF); NSF[CNS-0751152]; U.S. National Science Foundation (NSF); NSF[IIS-0713637]; U.S. National Science Foundation (NSF); NSF[OCE-0424602]; U.S. National Science Foundation (NSF); NSF[IIS-0534628]; NSF[CNS-0514485]; U.S. National Science Foundation (NSF); U.S. National Science Foundation (NSF); NSF[IIS-0513692]; U.S. National Science Foundation (NSF); NSF[CNS-0524096]; U.S. Department of Energy (DOE); US Department of Energy (DOE)...

STABLE PIECEWISE POLYNOMIAL VECTOR FIELDS

Pessoa, Claudio; Sotomayor, Jorge
Fonte: TEXAS STATE UNIV; SAN MARCOS Publicador: TEXAS STATE UNIV; SAN MARCOS
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.3%
Let N = {y > 0} and S = {y < 0} be the semi-planes of R-2 having as common boundary the line D = {y = 0}. Let X and Y be polynomial vector fields defined in N and S, respectively, leading to a discontinuous piecewise polynomial vector field Z = (X, Y). This work pursues the stability and the transition analysis of solutions of Z between N and S, started by Filippov (1988) and Kozlova (1984) and reformulated by Sotomayor-Teixeira (1995) in terms of the regularization method. This method consists in analyzing a one parameter family of continuous vector fields Z(epsilon), defined by averaging X and Y. This family approaches Z when the parameter goes to zero. The results of Sotomayor-Teixeira and Sotomayor-Machado (2002) providing conditions on (X, Y) for the regularized vector fields to be structurally stable on planar compact connected regions are extended to discontinuous piecewise polynomial vector fields on R-2. Pertinent genericity results for vector fields satisfying the above stability conditions are also extended to the present case. A procedure for the study of discontinuous piecewise vector fields at infinity through a compactification is proposed here.; FAPESP-Brazil [2011/13152-8]; FAPESP (Brazil); Programa Primeiros Projetos-PROPe/UNESP; Programa Primeiros ProjetosPROPe/UNESP

A comparative analysis of the relative efficacy of vector-control strategies against dengue fever

Amaku, Marcos; Coutinho, Francisco Antonio Bezerra; Raimundo, Silvia Martorano; Lopez, Luis Fernandez; Burattini, Marcelo Nascimento; Massad, Eduardo
Fonte: Springer; Nova York Publicador: Springer; Nova York
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.28%
Dengue is considered one of the most important vector-borne infection, affecting almost half of the world population with 50 to 100 million cases every year. In this paper, we present one of the simplest models that can encapsulate all the important variables related to vector control of dengue fever. The model considers the human population, the adult mosquito population and the population of immature stages, which includes eggs, larvae and pupae. The model also considers the vertical transmission of dengue in the mosquitoes and the seasonal variation in the mosquito population. From this basic model describing the dynamics of dengue infection, we deduce thresholds for avoiding the introduction of the disease and for the elimination of the disease. In particular, we deduce a Basic Reproduction Number for dengue that includes parameters related to the immature stages of the mosquito. By neglecting seasonal variation, we calculate the equilibrium values of the model’s variables. We also present a sensitivity analysis of the impact of four vector-control strategies on the Basic Reproduction Number, on the Force of Infection and on the human prevalence of dengue. Each of the strategies was studied separately from the others. The analysis presented allows us to conclude that of the available vector control strategies...

Um estudo histórico da evolução do conceito de potencial vetor no eletromagnetismo clássico; A historical study of the evolution of vector potential in classical electromagnetic theory

Pereira, Aldo Gomes
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 28/05/2009 Português
Relevância na Pesquisa
36.26%
Atualmente o potencial vetor é geralmente tratado no eletromagnetismo clássico como um artifício para o cálculo dos campos elétricos e magnéticos sem um significado claro. No entanto, quando foi proposto na metade do século XIX, ele possuía um significado físico claro e desempenhava um papel central para Faraday, Maxwell e outros físicos britânicos. Um dos objetivos deste trabalho é entender como se deu esta mudança na interpretação do conceito de potencial vetor. Para isto foi realizado um estudo histórico analisando as diferentes interpretações para este conceito partindo dos trabalhos de Faraday sobre indução eletromagnética, onde propôs o conceito de estado eletrotônico. Analisamos as contribuições de William Thomson que fortemente inspiraram Maxwell a sugerir diferentes interpretações para o conceito em trabalhos publicados ao longo de cerca de duas décadas até a publicação do Treatise on Electricity and Magnestism em 1873. No final do século XIX a interpretação dada por Maxwell ao conceito de potencial vetor começou a ser questionada por vários físicos. Uma das questões envolvidas neste processo foi a realidade das grandezas físicas. Nomes como Heaviside, Hertz e outros defendiam que as grandezas dotadas de realidade física na teoria eletromagnética eram os campos elétrico e magnético e não o potencial vetor. Com essa nova visão desenvolveram uma nova teoria eletromagnética próxima da que conhecemos atualmente. No entanto...

Bifurcações de campos vetoriais descontínuos; Bifurcations of discontinuous vector fields

Maciel, Anderson Luiz
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 14/08/2009 Português
Relevância na Pesquisa
36.28%
Seja M um conjunto compacto e conexo do plano que seja a união dos subconjuntos conexos N e S. Seja Z_L=(X_L,Y_L) uma família a um parâmetro de campos vetoriais descontínuos, onde X_L está definida em N e Y_L em S. Ambos os campos X_L e Y_L, assim como as suas dependências em L, são suaves i. e. de classe C^\infty; a descontinuidade acontece na fronteira comum entre N e S. O objetivo deste trabalho é estudar as bifurcações que ocorrem em certas famílias de campos vetoriais descontínuos seguindo as convenções de Filippov. Aplicando o método da regularização, introduzido por Sotomayor e Teixeira e posteriormente aprofundado por Sotomayor e Machado à família de campos vetoriais descontínuos Z_L obtemos uma família de campos vetoriais suaves que é próxima da família descontínua original. Usamos esta técnica de regularização para estudar, por comparação com os resultados clássicos da teoria suave, as bifurcações que ocorrem nas famílias de campos vetoriais descontínuos. Na literatura há uma lista de bifurcações de codimensão um, no contexto de Filippov, apresentada mais completamente, no artigo de Yu. A. Kuznetsov, A. Gragnani e S. Rinaldi, One-Parameter Bifurcations in Planar Filippov Systems...

Caracterização do padrão de integração do retrovírus pMFG-FVIII-P140K em linhagens celulares humanas produtoras de fator VIII recombinante; Characterization of the integration pattern of pMFG-FVIII-P140K retroviral vector in human cell lines producer of recombinant factor VIII

Freitas, Marcela Cristina Corrêa de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 14/03/2011 Português
Relevância na Pesquisa
36.3%
A hemofilia A é uma doença caracterizada pela deficiência do fator VIII (FVIII) de coagulação sanguínea e atinge 1 em 5000 homens. Países desenvolvidos, utilizam como terapia o FVIII recombinante (rFVIII), por apresentar maior segurança e consistir uma fonte ilimitada. Estudos realizados em nosso laboratório, utilizando o vetor retroviral pMFG-FVIII-P140K, originaram as linhagens celulares humanas, HepG2FVIIIdB/P140K (hepática) e Hek293FVIIIdB/P140K (renal), que foram selecionadas pelo mesmo sistema de seleção, o tratamento in vitro com as drogas Benzilguanina e Temozolomide. O presente trabalho teve por objetivo caracterizar e detalhar o padrão de integração do vetor retroviral pMFG-FVIII-P140K nas duas linhagens celulares humanas, e verificar se o perfil de integração está relacionado ao tipo celular específico ou se este sofre influência da estratégia de seleção a qual as células foram submetidas anteriormente. Foi utilizada a técnica de LM-PCR (ligação-mediada por PCR) que permite localizar o sítio de integração do vetor viral, por meio do sequênciamento do produto de PCR obtido após a digestão com enzimas de restrição e ligação de uma sequência adaptadora (LINKER) ao DNA genômico. Após o seqüenciamento as sequências foram submetidas a análises em bancos de dados de genomas (Human BLAT...

STABLE PIECEWISE POLYNOMIAL VECTOR FIELDS

Pessoa, Claudio; Sotomayor, Jorge
Fonte: Texas State Univ Publicador: Texas State Univ
Tipo: Artigo de Revista Científica Formato: 15
Português
Relevância na Pesquisa
36.3%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Processo FAPESP: 11/13152-8; Let N = {y > 0} and S = {y < 0} be the semi-planes of R-2 having as common boundary the line D = {y = 0}. Let X and Y be polynomial vector fields defined in N and S, respectively, leading to a discontinuous piecewise polynomial vector field Z = (X, Y). This work pursues the stability and the transition analysis of solutions of Z between N and S, started by Filippov (1988) and Kozlova (1984) and reformulated by Sotomayor-Teixeira (1995) in terms of the regularization method. This method consists in analyzing a one parameter family of continuous vector fields Z(epsilon), defined by averaging X and Y. This family approaches Z when the parameter goes to zero. The results of Sotomayor-Teixeira and Sotomayor-Machado (2002) providing conditions on (X, Y) for the regularized vector fields to be structurally stable on planar compact connected regions are extended to discontinuous piecewise polynomial vector fields on R-2. Pertinent genericity results for vector fields satisfying the above stability conditions are also extended to the present case. A procedure for the study of discontinuous piecewise vector fields at infinity through a compactification is proposed here.

Closed poly-trajectories and Poincaré index of non-smooth vector fields on the plane

Buzzi, C. A.; De Carvalho, T.; Da Silva, P. R.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 173-193
Português
Relevância na Pesquisa
36.3%
This paper is concerned with closed orbits of non-smooth vector fields on the plane. For a class of non-smooth vector fields we provide necessary and sufficient conditions for the existence of closed poly-trajectorie. By means of a regularization process we prove that hyperbolic closed poly-trajectories are limit sets of a sequence of limit cycles of smooth vector fields. In our approach the Poincaré Index for non-smooth vector fields is introduced. © 2013 Springer Science+Business Media New York.

O indice de Conley para campos de vetores descontinuos; The Conley index for discontinuous vector fields

Rogerio Casagrande
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 23/04/2008 Português
Relevância na Pesquisa
36.26%
O índice de Conley é um invariante topológico usado na análise do comportamento qualitativo de sistemas dinâmicos. Inicialmente a teoria foi desenvolvida para fluxos contínuos em espaços de dimensão finita e posteriormente estendida para o caso discreto. Neste trabalho, apresentamos uma teoria do índice de Conley para uma classe de campos vetoriais descontínuos, com descontinuidade de primeira espécie. Campos vetoriais descontínuos são freqüentes em varias áreas da Ciência e Engenharia e podem ser expressos por sistemas suaves por partes em uma variedade n-dimensional compacta M. Considere uma estratificação de Whitney de M e seja Z um campo descontínuo em M, onde a região de descohtinuidade, D, é o estrato de codimensão um. Mostramos a existência de um D-par índice (N, L) e sua invariância quanto ao tipo de homotopia do espaço N quocientado por L. Desta forma o D-índice de Conley fica bem definido e apresentamos alguns exemplos de seu cálculo. Utilizamos o D-Índice de ConIey para exibirmos condições suficientes para a existência de pontos de bifurcação em uma família a um parâmetro de campos descontínuos. Apresentamos uma teoria de continuação para D-grafos de Lyapunov associado à classe de campos descontínuos.; The Conley index is a used as a topological invariant in the analysis of the qualitative behavior of dynamical systems. lnitially the theory was developed for continuous flows in finite dimensional spaces and later extended to the infinite dimensional setting as well as to the discrete case. ln this work...

Estudo e implementação de inversor de tensão a três níveis com modulação em largura de pulsos por vetores espaciais aplicado ao controle vetorial de motor síncrono de imãs permanentes = : Study and implementation of three level voltage inverter with space vector modulation by pulse width modulation applied to vector control of permanent magnet synchronous motor; Study and implementation of three level voltage inverter with space vector modulation by pulse width modulation applied to vector control of permanent magnet synchronous motor

Marcos Fernando Espindola
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 30/07/2012 Português
Relevância na Pesquisa
36.31%
Apresenta-se a implementação de um inversor trifásico de tensão a três níveis para ser utilizado no controle de velocidade de um motor síncrono trifásico a imãs permanentes usando o método de controle vetorial. Realizou-se o estudo, projeto e construção de um inversor de tensão a três níveis com neutro grampeado ou inversor NPC neutral point clamped. Utilizou-se modulação em largura de pulsos por vetores espaciais no controle vetorial de velocidade do motor. Foram realizadas simulações do sistema proposto usando os aplicativos computacionais Matlab/Simulink e PSIM. Realizou-se em seguida uma montagem experimental constituída de um motor síncrono a imãs permanentes de 0,75 kW acoplado a um freio eletromagnético que lhe serviu de carga mecânica. O sistema motor e carga foi acionado pelo inversor com modulação em largura de pulsos por vetores espaciais e os resultados obtidos do controle de velocidade realizado, incluindo reversão de velocidade e frenação do motor, são apresentados no trabalho. Comparou-se também o desempenho de um inversor a três níveis usando modulação em largura de pulsos por vetores espaciais com o desempenho de um inversor a dois níveis usando modulação em largura de pulsos por vetores espaciais na alimentação de uma carga resistiva. Resultados de simulação e resultados experimentais são apresentados. Neste trabalho realizou-se uma comparação qualitativa entre o uso do inversor a dois níveis e do inversor a três níveis que mostra em que situações é conveniente utilizar o inversor a três níveis.; It is presented the implementation of a three phase three level voltage inverter to be used in the speed control of a three phase permanent magnet synchronous motor using the vector control method. To achieve this goal...

Support Vector Machines na previsão do comportamento de uma ETAR; Support Vector Machines on the prediction of a WWTP performance

Ribeiro, Daniel José Silva
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Dissertação de Mestrado
Publicado em 20/03/2013 Português
Relevância na Pesquisa
36.28%
Dissertação de mestrado em Engenharia Informática; O Data Mining é um processo de exploração de grandes quantidades de dados, com um potencial enorme para ajudar as empresas na extração de conhecimento que está oculto nos mais diversos sistemas de dados. Esta tecnologia é utilizada pelas empresas nos mais variados domínios, com o intuito de as ajudar em atividades de tomada de decisões. Entre os diversos campos de aplicações encontramos o domínio da Biologia e do Ambiente, em particular, as questões relacionadas com as Estações de Tratamento de Águas Residuais (ETAR). As ETAR são infraestruturas essenciais para manter o equilíbrio do meio-ambiente, sendo caracterizadas por terem várias fases de tratamento, nas quais são removidas impurezas como sólidos, matéria orgânica e nutrientes. Todo este processo dinâmico e complexo deve ser processado de forma eficiente, permitindo que o efluente final que nelas é tratado tenha a melhor qualidade possível. A previsão da qualidade da água tratada, com base nos vários fluxos que dão entrada nas ETAR, permite medir a eficácia do tratamento e, assim, obter alguma informação útil para um melhor controle de toda a infraestrutura. A ETAR em estudo neste trabalho de dissertação...

Satellite-derived estimation of environmental suitability for malaria vector development in Portugal

Benali, Akli; Nunes, J.P.; Freitas, F.B.; Sousa, C.A.; Novo, M.T.; Lourenço, P.M.; Lima, J.C.; Seixas, J.; Almeida, A.P.G.
Fonte: Elsevier Inc. Publicador: Elsevier Inc.
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.3%
Malaria was endemic in Europe for more than two millennia until it was eradicated in the 1970s. Recent autochthonous cases registered in Greece have increased the awareness regarding the threat of malaria re-emergence in Southern Europe. Currently, the presence of competent vectors, suitable environmental conditions and the evidences of a changing climate may increase the widespread re-emergence of malaria in Southern Europe. This work focused on determining the current relationships between environmental factors and the density of the former malaria vector Anopheles atroparvus in Portugal, a previously endemic country. Adult females were sampled and vector density was estimated in 22 sites in Southern Portugal between 2001 and 2010 and related with land cover and satellite-derived air temperature and vegetation indices. The relationship between vector density and current local larval habitat, temperature and, in a broader sense, to environmental conditions, was assessed using a statistical modelling approach. Results showed that present environmental conditions are suitable for vector development at high densities and the spatial and temporal patterns closely resemble the ones registered in the past endemic period. Statistical modelling of the relationships between environmental conditions and vector density...

Tracking source azimuth using a single vector sensor

Felisberto, P.; Santos, P.; Jesus, S. M.
Fonte: IEEE Publicador: IEEE
Tipo: Conferência ou Objeto de Conferência
Publicado em /07/2010 Português
Relevância na Pesquisa
36.3%
This paper aims at estimating the azimuth of an underwater acoustic source with a single vector sensor. A vector sensor is a device that measures the scalar acoustic pressure field and the vectorial acoustic velocity field at a single location in space. The actual sensor technology allows to build compact vector sensors, with an operational frequency response ranging from a few hertz to several tens of kilohertz, thus the same device can be used to receive shipping noise upto dolphin whistles. It is demonstrated that one can attain a reliable estimate of the azimuth of a source with a single vector sensor. The method presented is based on the inner product between the sampled acoustic field and the different particle velocity orthogonal components. The method is very simple and low computational demanding thus, well suited to be used in mobile or light platforms where space and/or computational power requirements is of concern. It is shown that the proposed method can be used either in time or in frequency domain, giving rise to easily estimating the azimuth of several sources with non-overlapping frequency bands. The data discussed herein (ship noise, communication signals, tomographic signals) were acquired during the Makai’2005 experiment using a four element vector sensor array. It is shown that the estimates obtained with a single vector sensor are comparable with those obtained with the full vector sensor array and are inline with the expected results as known from the geometry of the experiment.

Vector competence of Culex quinquefasciatus say from different regions of Brazil to Dirofilaria immitis

Ahid,Silvia Maria Mendes; Vasconcelos,Pádua Suely da Silva; Lourenço-de-Oliveira,Ricardo
Fonte: Instituto Oswaldo Cruz, Ministério da Saúde Publicador: Instituto Oswaldo Cruz, Ministério da Saúde
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2000 Português
Relevância na Pesquisa
36.28%
The vector competence of Culex quinquefasciatus from five localities in Brazil to Dirofilaria immitis was evaluated experimentally. Females from each locality were fed on an infected dog (~ 6 microfilariae/µl blood). A sample of blood fed mosquitoes were dissected approximately 1 h after blood meal. These results demonstrated that all had ingested microfilariae (mean, 4.8 to 24.6 microfilariae/mosquito). Fifteen days after the infected blood meal, the infection and infective rates were low in all populations of Cx. quinquefasciatus. The mean number of infective larvae detected in the head and proboscis of these mosquitoes was 1-1.5. The vector efficiency, the number of microfilariae ingested/number of infective larvae, was low for all populations of Cx. quinquefasciatus. However, the survival rate for all populations was high (range 50-75%). The survival rate of Aedes aegypti assayed simultaneously for comparison was low (24.7%), while the vector efficiency was much higher than for Cx. quinquefasciatus. These data suggest that the vector competence of all assayed populations of Cx. quinquefasciatus to D. immitis in Brazil is similar and that this species is a secondary vector due to its low susceptibility. Nevertheless, vector capacity may vary between populations due to differences in biting frequency on dogs that has been reported in Brazil.

Intrusive versus domiciliated triatomines and the challenge of adapting vector control practices against Chagas disease

Waleckx,Etienne; Gourbière,Sébastien; Dumonteil,Eric
Fonte: Instituto Oswaldo Cruz, Ministério da Saúde Publicador: Instituto Oswaldo Cruz, Ministério da Saúde
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/05/2015 Português
Relevância na Pesquisa
36.26%
Chagas disease prevention remains mostly based on triatomine vector control to reduce or eliminate house infestation with these bugs. The level of adaptation of triatomines to human housing is a key part of vector competence and needs to be precisely evaluated to allow for the design of effective vector control strategies. In this review, we examine how the domiciliation/intrusion level of different triatomine species/populations has been defined and measured and discuss how these concepts may be improved for a better understanding of their ecology and evolution, as well as for the design of more effective control strategies against a large variety of triatomine species. We suggest that a major limitation of current criteria for classifying triatomines into sylvatic, intrusive, domiciliary and domestic species is that these are essentially qualitative and do not rely on quantitative variables measuring population sustainability and fitness in their different habitats. However, such assessments may be derived from further analysis and modelling of field data. Such approaches can shed new light on the domiciliation process of triatomines and may represent a key tool for decision-making and the design of vector control interventions.

A Large-scale Dynamic Vector and Raster Data Visualization Geographic Information System Based on Parallel Map Tiling

Wang, Huan
Fonte: FIU Digital Commons Publicador: FIU Digital Commons
Tipo: Artigo de Revista Científica Formato: application/pdf
Português
Relevância na Pesquisa
36.36%
With the exponential increasing demands and uses of GIS data visualization system, such as urban planning, environment and climate change monitoring, weather simulation, hydrographic gauge and so forth, the geospatial vector and raster data visualization research, application and technology has become prevalent. However, we observe that current web GIS techniques are merely suitable for static vector and raster data where no dynamic overlaying layers. While it is desirable to enable visual explorations of large-scale dynamic vector and raster geospatial data in a web environment, improving the performance between backend datasets and the vector and raster applications remains a challenging technical issue. This dissertation is to implement these challenging and unimplemented areas: how to provide a large-scale dynamic vector and raster data visualization service with dynamic overlaying layers accessible from various client devices through a standard web browser, and how to make the large-scale dynamic vector and raster data visualization service as rapid as the static one. To accomplish these, a large-scale dynamic vector and raster data visualization geographic information system based on parallel map tiling and a comprehensive performance improvement solution are proposed...

Sylvatic triatominae: a new challenge in vector control transmission

Guhl,Felipe; Pinto,Nestor; Aguilera,Germán
Fonte: Instituto Oswaldo Cruz, Ministério da Saúde Publicador: Instituto Oswaldo Cruz, Ministério da Saúde
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/07/2009 Português
Relevância na Pesquisa
36.28%
Over the last 10 years, Uruguay, Chile and Brazil have been certified as being free from disease transmission by Triatoma infestans, the main domiciliated vector for Chagas disease in the Southern Cone countries. This demonstrates that programmes addressing the vector for the disease's transmission are effective. These programmes have resulted in a dramatic decrease in the incidence of Chagas disease in Latin America. Guatemala was certified a few months ago as being free from disease transmission by Rhodnius prolixus, the main domiciliated vector for Chagas disease in Central American countries. However, the main concern for different countries' current control programmes is the continuity and sustainability of future vector control actions. The prevalence and incidence figures for individuals infected by Trypanosoma cruzi in Mexico and Andean and Central American countries highlights the need for broadened strategies in the struggle against the disease and its vectors. A number of triatomine insects are parasite vectors, each with a different life history. Therefore, it is important that new vector control strategies be proposed, keeping in mind that some species are found in peridomiciliary areas and wild ecotopes. The only viable control strategy is to reduce human interactions with vector insects so that the re-infestation and re-colonisation of human habitats will not take place.

A Single Amino Acid Position in the Helper Component of Cauliflower Mosaic Virus Can Change the Spectrum of Transmitting Vector Species

Moreno, Aránzazu; Hebrard, E.; Uzest, M.; Blanc, S.; Fereres, Alberto
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artículo Formato: 4085 bytes; image/gif
Português
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Viruses frequently use insect vectors to effect rapid spread through host populations. In plant viruses, vector transmission is the major mode of transmission, used by nearly 80% of species described to date. Despite the importance of this phenomenon in epidemiology, the specificity of the virus-vector relationship is poorly understood at both the molecular and the evolutionary level, and very limited data are available on the precise viral protein motifs that control specificity. Here, using the aphid-transmitted Cauliflower mosaic virus (CaMV) as a biological model, we confirm that the "noncirculative" mode of transmission dominant in plant viruses (designated "mechanical vector transmission" in animal viruses) involves extremely specific virus-vector recognition, and we identify an amino acid position in the "helper component" (HC) protein of CaMV involved in such recognition. Site-directed mutagenesis revealed that changing the residue at this position can differentially affect transmission rates obtained with various aphid species, thus modifying the spectrum of vector species for CaMV. Most interestingly, in a virus line transmitted by a single vector species, we observed the rapid appearance of a spontaneous mutant specifically losing its transmissibility by another aphid species. Hence...

Edge enhancement in multispectral satellite images by means of vector operators

Lira,Jorge; Rodríguez,Alejandro
Fonte: Instituto de Geofísica, UNAM Publicador: Instituto de Geofísica, UNAM
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2014 Português
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Edge enhancement is an element of analysis to derive the spatial structure of satellite images. Two methods to extract edges from multispectral satellite images are presented. A multispectral image is modeled as a vector field with a number of dimensions equal to the number of bands in the image. In this model, a pixel is defined as a vector formed by a number of elements equal to the number of bands. Two vector operators are applied to such vector field. In our first method, we extend the definition of the gradient. In this extension, the vector difference of the window central pixel with neighboring pixels is obtained. A multispectral image is then generated where each pixel represents the maximum change in spectral response in the image in any direction. This image is named a multispectral gradient. The other method, considers the generalization of the Laplacian by means of an η-dimensional Fourier transform. This image is named a multispectral Laplacian. The vector operators perform a simultaneous extraction of edge-content in the spectral bands of a multispectral image. Our methods are parameter-free. Our methods work for a multispectral image of any number of bands. Two examples are discussed that involve multispectral satellite images at two scales. We compare our results with widely used edge enhancement procedures. The evaluation of results shows better performance of proposed methods when compared to widely used edge operators.