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  • 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.
11

Participação de celulas T regulatorias (CD4+CD25+) na imunossupressão observada em pacientes com paracoccidioidomicose / Participation of regulatory T'cells (CD4+CD25+) in the immunossupression observed on paracoccidioidomycosis

Ferreira, Maria Carolina, 1983- 02 February 2009 (has links)
Orientadores: Ronei Luciano Mamoni, Maria Heloisa Souza Lima Blotta / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-13T02:22:29Z (GMT). No. of bitstreams: 1 Ferreira_MariaCarolina_M.pdf: 3235698 bytes, checksum: 858844d8c2fb54db25e9acd5fcdbb327 (MD5) Previous issue date: 2009 / Resumo: Pacientes com paracoccidioidomicose (PCM) apresentam supressão da resposta imunológica celular, caracterizada por testes de hipersensibilidade do tipo tardio negativos a antígenos do P. brasiliensis, alta taxa de apoptose de linfócitos e alta expressão de CTLA-4 (CD152) e alta produção de citocinas supressoras (IL-10 e TGF-b). Esses dados indicam a possível participação de células T regulatórias (CD4+CD25+ - Tregs) na PCM. O objetivo desse trabalho foi verificar se, e por qual mecanismo as células T regulatórias estão envolvidas nessa imunossupressão. Para isso, analisamos o número, fenótipo, assim como a atividade funcional das células regulatórias do sangue periférico de pacientes com PCM antes e após o tratamento antifúngico efetivo. O número e o fenótipo das células T regulatórias foram avaliados por citometria de fluxo, e os resultados demonstraram que pacientes com PCM ativa (DA) apresentam um maior número dessas células que pacientes tratados (DT) ou controles normais (C). Além disso, observamos uma maior expressão de CD95L, CTLA-4, LAP-1 e GITR em células regulatórias do grupo DA em relação aos grupos DT e C. A expressão do RNAm (quantificado por PCR em tempo real) para FoxP3, IL-10 e TGF-ß em CMSP ex vivo também foram maiores no grupo DA que nos controles e pacientes do grupo DT. Com o intuito de comparar a atividade funcional das células T regulatórias, analisamos o efeito da cocultura com células T regulatórias na resposta proliferativa de CMSP estimuladas com ConA. As células regulatórias do grupo DA exibiram uma atividade supressora maior que as provenientes do grupo DT ou C, de uma maneira dose dependente. Para verificar se o mecanismo por meio do qual as células regulatórias exercem sua atividade é dependente de contato, utilizamos um sistema "transwell". Os resultados demonstraram que a atividade supressora das células T regulatórias do grupo controle é dependente de contato, mas que essa atividade para as células provenientes dos pacientes do grupo DA é apenas parcialmente revertida com esse sistema. A adição de citocinas supressoras recombinantes (IL-10 e TGF-ß), assim como de anticorpos neutralizantes para essas citocinas nas coculturas, mostrou que a produção de citocinas regulatórias pode ser outro mecanismo utilizado pelas células regulatórias do grupo DA. Em conclusão, o número aumentado de células T regulatórias no sangue periférico de pacientes com DA, expressando altos níveis de moléculas associadas à atividade regulatória, ao lado da alta expressão do RNAm para FoxpP3, IL-10 e TGF-b, sugere uma participação dessa população de linfócitos na imunossupressão observada em pacientes com PCM ativa. Além disso, nossos resultados indicam que as células T regulatórias dependem principalmente do contato intercelular para exercer seus efeitos supressores, e que a produção de citocinas supressoras também está envolvida nesse processo. / Abstract: Patients with paracoccidioidomycosis (PCM) present suppression of cellular immune response characterized by negative DTH to P. brasiliensis antigens, elevated apoptosis of lymphocytes, high expression of CTLA-4, and production of IL-10 and TGF-ß. Together these data point towards the involvement of regulatory T cells (CD4+CD25+ - Tregs) in PCM. The aims of this study were to verify whether and how Tregs are involved in this immunosuppression, through the analysis of the number and the phenotype, as well as, the functional activity of Tregs cells from peripheral blood of patients before and after antifungal treatment. The number and phenotype of Tregs cells were evaluated by flow cytometry, and the results showed that PCM patients with active disease (AD) present higher number of Treg cells than patients after treatment (TD) or healthy controls (C). Furthermore, we observed higher expression of CD95L, CTLA-4, LAP-1 and GITR on Tregs from AD group, than in cells from TD and C groups. mRNA expression (quantified by qRT-PCR) for FoxP3, IL-10 and TGF-ß in ex vivo PBMC, were also higher in AD group than in controls and in TD group. In order to compare the functional activity of Tregs, we analyzed the effect of Treg cells on the proliferative response of PBMC stimulated with ConA. Tregs from AD group exhibited stronger regulatory activity than cells from TD and C groups, in a dose dependent manner. To verify the possible mechanism through which Tregs suppress the cell proliferation we utilized a transwell system, which showed that the contact is mandatory for regulatory activity of Treg cells from C group, but had only a partial involvement in cells from AD patients. The addition of IL-10 and TGF-ß and anti cytokines in the co-cultures showed that the production of immunoregulatory cytokines may be other mechanism used by Tregs. In conclusion, the increased number of Treg cells in peripheral blood of patients with active disease, expressing high levels of regulatory markers and suppressive activity, besides the high expression of Foxp3, IL-10 and TGF-ß mRNAs suggest the potential participation of this population in the immunosuppression observed during the disease. Moreover, our results indicate that Tregs act mainly by contact to exert their inhibitory effects, but the production of immunoregulatory cytokines are also involved. / Mestrado / Ciencias Biomedicas / Mestre em Ciências Médicas
12

Supressão condicionada sobre linhas de base de variabilidade e repetição operantes / Conditioned suppression in operant variability and repetition

Paola Bisaccioni 23 June 2010 (has links)
A supressão condicionada é definida como a redução na taxa de resposta operante diante de um estímulo que foi previamente pareado com um evento aversivo inevitável e independente do comportamento do sujeito. A linha de base na qual se sobrepõe os pareamentos tem sido apontada como uma das variáveis críticas na determinação do efeito supressivo. Portanto, o objetivo desse trabalho foi verificar se esquemas de reforçamento contingentes à variabilidade ou à repetição do comportamento seriam igualmente sensíveis ao procedimento de supressão condicionada. Ratos foram divididos em dois grupos (n=6), denominados Variabilidade (VAR) e Repetição (REP), que diferiram apenas quanto ao esquema de reforçamento da linha de base. Os sujeitos do grupo VAR foram submetidos a uma contingência que exigia que eles emitissem diferentes seqüências de quatro respostas de pressão a duas barras (esquema RDF). Já os sujeitos do grupo REP foram reforçados por emitir uma única seqüência (seqüência EEEE). Depois de 25 sessões sob esses esquemas, foram introduzidos os pareamentos aversivos, que consistiram na apresentação de duas luzes de 12 V, por 20 s, localizadas em cima de cada barra, que foram regularmente seguidas por choques de 0,8 mA por 0,5 s. Os resultados indicaram que os dois grupos foram sensíveis aos pareamentos CS-US, mostrando queda na taxa de resposta operante frente ao estímulo condicionado. Embora todos os sujeitos tenham apresentado forte efeito supressivo, a supressão foi mais acentuada no Grupo REP. No entanto, as diferenças obtidas nas razões de supressão dos dois grupos foram pequenas considerando a magnitude das diferenças entre as contingências de reforçamento utilizadas, que selecionavam padrões opostos em relação à variabilidade do comportamento. Discutiu-se que alguns parâmetros utilizados poderiam explicar a pequena diferença obtida aqui em comparação com os estudos da literatura. Os resultados apontaram ainda que os padrões de variar e repetir não foram afetados pela exposição ao US aversivo, mantendo-se no final do experimento os mesmos níveis da linha de base. Portanto, os dados sugerem que a variabilidade operante pode coexistir com contingências aversivas, ampliando o potencial de análise da variação do comportamento, que usualmente é investigada apenas com reforço positivo / Conditioned suppression is defined as a decrease in the rate of a positively reinforced response during a stimulus which precedes an unavoidable shock. The reinforcement schedule used to maintain the baseline performance is an important variable in determining the degree of suppression. Therefore, the purpose of the present study was to compare the effects of different reinforcement schedules that selected behavioral variation or repetition in the conditioned suppression procedure. Rats were divided into two groups (n=6), named Variability (VAR) and Repetition (REP), that differed from each other in relation to the reinforcement schedules used to maintain the baseline. In VAR Group, rats were rewarded for variable response sequences. In REP Group, rats were rewarded for repeating a single LLLL sequence. After 25 sessions in these schedules, periods of light (20 sec.) were terminated with a brief, unavoidable shock (0.8 mA/ 0.5 sec.) for the two groups. The results indicated that the rate of operant response of all subjects decrease during the CS. Therefore all subjects showed strong suppression, the effect was more severe in REP Group. However, the difference obtained was small considering the differences in the reinforcement schedules that selected opposite performances related to behavioral variation. It was discussed that some parameters of this experiment could explain the small difference obtained here in contrast with previous studies. The results also showed that variation and repetition sequences are not affected by the aversive US. Thus, the data suggest that operant variability could be maintained in aversive contingencies
13

Opresión, crueldad y represión sexual en La casa de Bernarda Alba / Opression, cruelty, and repression of sexual desires in La casa de Bernarda Alba

Wåhlin Landa, Helena January 2020 (has links)
Esta tesina presenta un análisis temático de la obra de teatro La casa de Bernarda Alba escrita por Federico García Lorca partiendo de las contribuciones teóricas de Michel Foucault, un enfoque metodológico inspirado por el esquema actancial presentado por Eduardo Jimenez Tornatore así como una visión histórica y biográfica de Martha Ackelsberg y Reed Anderson. Uno de los objetivos es analizar los temas relacionados con la opresión y la represión de los deseos sexuales. Un segundo, mirar las acciones e interacciones entre los personajes y cómo estas reflejan las reglas sociales de corte conservador cumpliendo una función dentro de la obra.  Los resultados muestran conflicto y tensión bajo condiciones de dominación, opresión y represión sexual como se señala en cada tema seleccionado a través de iluminar citas, símbolos y descripciones de los actos igual que dibujar paralelos a las teorías sobre la sexualidad y al modelo actancial. Palabras claves: Mujer, Costumbres, Muerte, Matrimonio, Clase, Sexualidad, Opresión, Supresión. / This essay presents a thematic analysis of the drama La casa de Bernarda Alba written by Federico García Lorca using theoretical contributions from Michel Foucault, a methodological approach inspired by the work Eduardo Jimenez Tornatore as well as historical and biographical insight from Martha Ackelsberg and Reed Anderson. One objective is to analyze the themes that surface relating to oppression and to the repression of sexual desires. A second, to look at the actions and interactions between the characters and how they relate to the societal rules at the time as well as to their respective function in the drama. The results show conflict and tension under conditions of domination, oppression and repression as pointed out in each selected theme through quotes, symbols, scene descriptions and while drawing parallels to theories on sexuality and to the actantial model.
14

RECUPERANDO O IMAGINÁRIO DA DEUSA: ESTUDO SOBRE A DIVINDADE ASERÁ NO ANTIGO ISRAEL / Recovering the Imagination of Goddess: study about the divinity Asherah in the ancient Israel

Cordeiro, Ana Luisa Alves 12 August 2009 (has links)
Made available in DSpace on 2016-07-27T13:49:46Z (GMT). No. of bitstreams: 1 ANA LUISA ALVES CORDEIRO.pdf: 1151113 bytes, checksum: f7942a3c4ac0cf3c9c0de1dc63942b13 (MD5) Previous issue date: 2009-08-12 / To several readers of the holy Bible the idea of a single God, Yahweh, seems to be clear. Thought, the Bible and some other archaeological discoverys shows that things were not always like this. Before a monotheist theological elaboration on ancient Israel, there was a religious polytheistic reality, wich Yahweh was part of. The research intend to clarify this reality, questioning for the presence of the female divinity, specially Asherah, for the impacts of Josiah reform (around the VII b.C. century, in the ancient Israel) and the important points on the discution about the Goddess nowadays. The research intend to study 2Kings 23,4-7, showing that are actions taken for the good of monotheism, are held by intolerance, violence and suppression of the other. The female representation, while Goddess, was present in the ancient Israel and even suppressed in the monotheist elaboration process, the Goddess continue resurging nowadays like symbolic possibility to imagine the holy. / Para a maioria das pessoas que lêem a Bíblia, a idéia de um único Deus, Javé, parece ser clara. No entanto, tanto a Bíblia quanto algumas descobertas arqueológicas deixam entrever que nem sempre foi assim. Antes de uma elaboração teológica monoteísta no antigo Israel havia uma realidade religiosa politeísta, da qual Javé também fazia parte. A pesquisa busca elucidar essa realidade, perguntando pela presença da divindade feminina, em especial Aserá, pelos impactos da reforma de Josias (em meados do século VII a.C., no antigo Israel) e as relevâncias da discussão sobre a Deusa na atualidade. A pesquisa busca analisar o texto de 2Reis 23,4-7, demonstrando que se trata de medidas impetradas em prol do monoteísmo, permeadas de intolerância, violência e supressão do(a) outro(a). A representação feminina, enquanto Deusa, esteve presente no antigo Israel e apesar de suprimidas no processo de elaboração monoteísta, as Deusas continuam ressurgindo na atualidade como possibilidade simbólica de imaginar o sagrado.
15

Unfair competition and the safeguard of trade secrets / Competencia desleal y resguardo de los secretos empresariales

Sosa Huapaya, Alex 25 September 2017 (has links)
The Law of Supression of Unfair Competition, approved by Legislative Decree 1044, tries to avoid confusions about what is protected as a trade secret and what cases of misappropriation should be sanctioned.In this article, the author questions the interpretation and application that has beenconsistently employed, in many cases, to some of the terms contained in the aforementioned law.For that purpose, the author explains the meaning of the trade secret and other related terms, such as prohibited competition and concurrent purposes. He then proceeds to elaborate an analysis about the economic function of protecting trade secrets and what should be the correct application of the Law of Supression of Unfair Competition. / La Ley de Represión de la Competencia Desleal, aprobada por el Decreto Legislativo 1044, trata de evitar confusiones acerca de qué se protege comosecreto empresarial y qué supuestos de apropiación indebida deberían sancionarse.En el presente artículo, el autor cuestiona la interpretación y aplicación que se le ha venido dando, en muchos casos, a algunos de los términos contenidos en dicha ley. Para ello, explica el significado del secreto empresarial, y de otros términosrelacionados como la competencia prohibida y la finalidad concurrencial. Luego, pasa a elaborar un análisis sobre la función económica de proteger los secretos empresariales y de cuál debería ser la correcta aplicación de la Ley de Represión de la Competencia Desleal.
16

Source Localization and Speech Enhancement for Speech Recognition for Real time Environment

Muhammad, Asim, Ali, Akbar January 2012 (has links)
Popularity of speech communication is rapidly increasing in various contexts such as conferencing systems, mobile/fixed electronic devices and laptops thus leading to a heightened demand for new services and improved speech quality. Dictaphones used for dictations usually have one microphone. Single microphone does not give enough degree of freedom to allow estimation of location of the source. Microphone array makes use of multiple microphones for spatial filtering suppressing the background noise. This report aims for speech enhancement utilizing the benefits inherited with microphone arrays to find direction of desired speaker and focus the listening beam in that direction. A comparison is made between Generalized Cross Correlation (GCC) methods for locating the source in real office environment. Beamforming is implemented to make the microphone array listen in the desired direction thus reducing the interference from other sources. Minimum Variance Distortion-less Response (MVDR) approach is shown to give better results compared to more simplistic techniques. Perceptual based Eigen filter incorporating human hearing models in subspace incorporated in the suppressor eliminates the residual noise. Objective system performance is evaluated by estimating Signal-to-Noise-Ratio improvement (SNRI), segmental SNR, signal degradation and noise suppression. Perpetual Evaluation of Speech Quality (PESQ) gives Mean Opinion Score for subjective evaluation. / asim_zolo@yahoo.com, akbarali45@gmail.com
17

Iterative Evaluation and Control Methods for Disturbance Suppression on a High Precision Motion Servo

Thunberg, Claes, Kastensson, Klara January 2023 (has links)
Moore’s law states that the number of transistors in an Integrated Circuit (IC) doubles every two years. Ever-increasing performance in mask writing machinery is therefore required being the first step in the manufacturing process. Many factors affect the quality of the end product, with the motion control system playing an important role. This thesis analyzes the performance of the motion controller for the positioning system in a mask writer application. The target motion in the X-axis in the mask writer is by design highly repetitive and predictable. As of today a feedforward-feedback controller is used, tuned for low deviation during writing. In this thesis it is found that the motion control can be improved by exploiting the repetitive nature of the motion task. Two iterative methods are explored, Iterative Feedback Tuning (IFT) and Iterative Learning Control (ILC). IFT is implemented as a parameter optimizing method for the existing Proportional-Integral-Derivative (PID) controller. Given suboptimal initial parameters the algorithm converges to a global minimum using a cost function to minimize total deviation and constraints on the maximum deviation. With the optimized parameter settings an improvement of a 31 % decrease in total deviation is seen compared to the default setting. ILC is implemented as a replacement to the current controller in an exposure motion. With the use of saved data from previous iterations the control signal is updated and refined to better suit the target motion. ILC is a promising method within high precision motion control by virtue of not needing a model of the system and its ability to suppress reoccurring disturbances. The algorithm achieves an improvement of a 94% decrease in total deviation during writing compared to the current controller. However, with this implementation long term stability is not guaranteed. A stable implementation of the algorithm tested on a test rig achieves an improvement of a 79.8% decrease in deviation during writing compared to the current feedforward-feedback controller. Additionally, correlations between parameter values of the current feedback controller and servo characteristics are analyzed to aid in the manual tuning process. Tuning the PID controller for fast rise time decreases the total deviation during writing. The derivative gain in the controller should be high to decrease the overshoot caused by the aggressive controller. This will induce some oscillations into the system, however not at the cost of performance as a result of the smooth motion during writing.
18

Recognition And Suppression Of Blends In A Tessellated Solid Model

Garg, Anup 02 1900 (has links)
Blend recognition and suppression from a tessellated model is important in applications such as model simplification in analysis and collaborative design where tessellated models are being used. This could also be used to pre-process the model before attempting to recognize form features in it. A procedure is described for recognizing and subsequently suppressing blends (fillets/rounds) in a tessellated model of a part. Earlier efforts on recognizing secondary features such as blends have used the boundary representation (B-Rep) of the part as input. Blend recognition and suppression from a tessellated model has not been addressed to the best of our knowledge. There has been work reported on the related problem of segmentation of tessellated surfaces. Segmentation refers to the decomposition of the object into regions where the underlying surfaces having similar characteristics. The segmented surface may be of any of surface like plane surface. There are two broad approaches to segmentation - vertex-based and edge-based. The vertex-based method clusters triangles consisting of connected vertices having the same attribute. One drawback of this method is that the boundaries of the clustered regions are not clearly defined due to difference in the labels of contiguous vertices. The edge-based method is based upon the dihedral angle at each edge in the tessellated model. The main drawback of this method is that edges in the boundary of the segmented patches are disconnected. This will result in an incomplete bounding loop when used for recognizing features. Smooth transitions at the boundary of features cannot be trapped with this approach. These techniques cannot be therefore used for recognizing blends. There have been efforts to recognize and suppress blends in a B-Rep model. Suppressing blend features in a B-Rep model is easier (compared to suppression from tessellated model) because smooth edges provide a clue to presence of blends. In the case of a tessellated model, the bounding loop of blends will not consist of smooth edges and no explicit signature is available for blends. In B-Rep model, information about the radius of blend is also available while this is not directly available in a tessellated model. Constant radius blends meet the requirements of most blending features encountered in mechanical part design. The surfaces forming a constant radius blend may be classified as cylindrical, spherical and toroidal surfaces. Spherical blend is formed by a blending operation at a vertex at which either three concave linear edges or three convex linear edges are incident. Blending operation on a linear edge forms cylindrical blend. Toroidal blend is formed by a blending operation on a circular edge. This circular edge may be closed (end vertices are identical) or open. Toroidal blend is also formed at a vertex at which at least one convex and one concave edge is incident. So toroidal blend can be classified into closed toroidal blend, open toroidal blend and vertex toroidal blend. In recognition process, for every triangle, cylindrical, spherical and toroidal surface parameters are calculated. In the second step, triangles having same surface parameters are clustered. The cluster of triangles are then classified as a blend or a form feature. Finally, toroidal blends are classified as one of the three types of toroidal blend. Procedures for the suppression of edge cylindrical blend and edge toroidal blend are described. At the present time, vertex blends are not suppressed individually. Rather in the process of suppressing edge blends, vertex blends are also suppressed. The parent surfaces that were blended are identified using the bounding loops of the blends. Triangles in the blend are then deleted and the parent surfaces are extended to suppress the feature. The key issues in suppression are - identification of all the surfaces at the blend, identification of the entities that were blended (edges and vertices) and updating the tessellated model. Results of constant radius blend recognition and suppression, on benchmark parts from NIST design repository are presented. This is followed by a discussion on the correctness of the recognition procedures. The thesis concludes by summarizing the contributions and identifies the following are as recognition of variable radius blends, blends on non-linear surfaces, suppression of all small volumetric feature as areas for further research.
19

Analise da expressão diferencial de genes de citros em resposta a infecção por Xanthomonas axonopodis pv. citri / Differential gene expression of citrus in response to infection by Xanthomonas axonopodis pv. citri

Camillo, Luciana Rodrigues 13 July 2006 (has links)
Orientador: Celso Eduardo Benedetti / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-07T07:02:38Z (GMT). No. of bitstreams: 1 Camillo_LucianaRodrigues_M.pdf: 5919875 bytes, checksum: 5cf571ac0a143a68d6340c3ad3c97f49 (MD5) Previous issue date: 2006 / Resumo: A doença cancro cítrico, causada pela bactéria Xanthomonas axonopodis pv. citri (Xac), emergiu como uma das principais ameaças à citricultura brasileira pois afeta todas as variedades comerciais de citros, diminuindo a produção e qualidade dos frutos e podendo se dispersar rapidamente em áreas de cultivo de citros. Entre os gêneros de Xanthomonas, foram encontrados muitos genes associados com patogenicidade e virulência, entretanto, pouco se conhece sobre os mecanismos envolvidos nas interações entre Xac e laranjeira e os genes envolvidos no desenvolvimento dos sintomas do cancro cítrico em folhas de citros (Citrus sinensis) em resposta à infecção por Xac. Neste trabalho, foi analizada a expressão diferencial de genes envolvidos no desenvolvimento do cancro cítrico em folhas de laranja, em resposta à infecção por Xac. Para tanto foram construídas duas bibliotecas de Hibridização Subtrativa Suprimida (SSH) com mRNAs de folhas infiltradas com Xac ou H20 após 10 dias de inoculação. O "screnning" das bibliotecas foi feito por dot blot e 17 genes diferencialmente expressos foram sequenciados e identificados por homologia no banco de dados ncbi-BLAST contra o banco de dados de EST de citros. A expressão gênica diferencial foi analizada por Northern Blot e PCR em tempo real (qPCR). Para complementar nossos dados, a expressão dos 17 genes diferenciais foi aI).alisada a partir de cDNAs de folhas de citros que foram infiltradas com Xac, H20 ou Xanthomonas axonopodis pv. aurantifolii (Xaa), que não é patogênica à laranja, mas causa cancro no limão galego. Nossos resultados demonstraram que Xac e Xaa induzem e reprimem o mesmo grupo de genes, porém em diferentes níveis. Nós identificamos que ambos patóg;enos alteram as vias de transdução de sinal de auxina, tráfico e fusão de vesículas, resposta de defesa e doença, síntese de proteínas e ciclo celular, metabolismo de carbono-nitrogênio e metabolismo secundário. A análise desses genes poderá ser de grande importância para o entendimento dos eventos que levam ao desenvolvimento dos sintomas do cancro / Abstract: The citrus canker disease, caused by Xanthomonas axonopodis pv. citri (Xac), has emerged as one of the major threats to the Brazilian citriculture because it affects all commercial citrus varieties, decreases the production and quality of the fruits and can spread rapidly in the citrus growing areas. The symptoms include canker lesions, leading to abscission of fruits and leaves and general tree decline. Within the genus Xanthomonas, several genes have been found associated with pathogenicity and virulence. However, little is known about the mechanisms involved in the Xac- citrus interaction and the development of the canker disease. In this work we analyzed the differential expression of genes involved in the development of the canker disease in sweet orange (Citrus sinensis) leaves in response to Xac infection. Therefore we constructed two Supression Subtracted Hybridization (SSH) libraries with mRNA from leaves infiltrated with Xac or water after 10 days of inoculation. The libraries were screnned by dot blot and the 17 differentially expressed genes were sequenced and identified through BLAST searches against the Citrus EST and protein databases. The differential gene expression was evaluated by Northem blot and Real Time PCR (qPCR). To complement our analysis, the expression of 17 genes was compared in cDNA samples from citrus leaves that had been infilt:r:ated with Xac, water or X axonopodis pv. aurantifolii (Xaa), wich is not pathogenic to orange but causes canker in key lime. Our results show that Xac and Xaa induce and repress a similar set of genes, however at different leveis. We found that both pathogens altered the pathways of auxin transport and signaling, vesicle trafficking and transport, cell cycle and protein synthesis, photorespiration and disease response. Further analysis of these genes will be of great importance to understand the events triggering the development of the canker symptoms / Mestrado / Genetica de Microorganismos / Mestre em Genética e Biologia Molecular
20

A Neural Network based Background Supression Technique applied to Vhe Gamma Ray Data coming from the Crab Pulsar

Reuschle, Christian A 01 January 2008 (has links) (PDF)
In this thesis we present new results for the 99.9% confidence level flux upper limits on the pulsed VHE gamma ray signal coming from the Crab pulsar. In order to achieve optimum hadronic background suppression we implement a new neural network based selection technique and apply it to Cherenkov shower imaging data from the WHIPPLE 10m IACT telescope at Mount Hopkins Arizona. Special emphasis will be given to the fact that the neural network selector is trained with real data exclusively. An energy estimator for gamma ray induced extensive air shower events has been derived from Monte Carlo simulations using the Monte Carlo framework GrISU. This estimator, applied to the image data, serves as input to the neural set selector and is needed to determine the energy dependent flux upper limits. We compare our results to the results from previous studies and the performance of our neural network selection technique to the so-called Supercuts and Optimized Supercuts methods.The new flux upper limits and the new technique show the potential to settle the question about the production mechanism of pulsar radiation. However, the current analysis does not answer this question fully.

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