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1
Schaefer, Estelle. "Contrôle spatial de la division cellulaire chez les plantes : rôle des protéines TRM6-TRM7-TRM8 d’Arabidopsis thaliana dans la formation de l’anneau de préprophase." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112042/document.
Full textAbstract:
Les cellules végétales sont entourées d’une paroi pecto-cellulosique rigide, soudant les cellules les unes aux autres et empêchant toute migration. Lors de la mitose, le positionnement du plan de division est donc un processus fondamental dans l’organisation des tissus puisque les cellules nouvellement formées restent à leur position initiale après la cytokinèse. Chez les plantes terrestres, le plan de division est déterminé lors de la transition G2/M du cycle cellulaire par l’anneau de préprophase (PPB), une structure transitoire corticale de microtubules. Les mécanismes mis en jeu pour la formation de la PPB sont encore inconnus. L’équipe dans laquelle j’ai effectué ma thèse a identifié un complexe régulateur, le complexe TTP, composé de TON1, de la famille de protéines TON1-Recruiting-Motif (TRMs) et d’une phosphatase de type 2A où FASS est la sous-unité régulatrice. TON1 et FASS sont impliquées dans l’organisation des microtubules corticaux en interphase, et sont indispensables à la formation de la PPB. La famille des protéines TRMs, identifiée récemment, est composée de 34 membres, dont certains sont capables de se lier aux microtubules et de recruter TON1 et FASS au cytosquelette. Les profils d’expression des TRMs et les analyses génétiques préliminaires suggèrent que certaines auraient un rôle en interphase, alors que d’autres pourraient être impliquées dans la formation de la PPB. Mon projet était d’identifier et de caractériser, si elles existent, les TRMs impliquées spécifiquement dans la formation de la PPB. L’analyse des données de transcriptome a révélé qu’un des gènes de la famille TRM, le gène TRM7, présente un pic d’expression en mitose. Nous avons d'abord montré que TRM7 est spécifiquement exprimée dans les tissus en division. L’utilisation d’une fusion génomique TRM7-3xYpet indique d'autre part que la protéine TRM7 n’est exprimée qu’au stade G2/M. Elle est localisée à la PPB et disparaît en début de métaphase, peu après dépolymérisation de la PPB. TRM7 est ainsi le seul marqueur spécifique de la PPB identifié à ce jour chez les plantes, puisque toutes les autres protéines localisées à la PPB marquent également les autres structures mitotiques ou le cytosquelette d’interphase. TRM7 fait partie d’un sous-groupe de trois TRM partageant environ 74% de similarité de séquence. L’analyse phénotypique du mutant trm7, ainsi que celui du triple mutant trm6 trm7 trm8 a montré que ce sous-groupe de protéines joue un rôle majeur dans la formation de la PPB. Près de la moitié des cellules du mutant trm7 présentent un stade préprophase aberrant alors que 100% des cellules du triple mutant au stade G2/M sont affectées, la très grande majorité se divisant sans former de PPB. Étonnamment, la morphologie de ces mutants est peu perturbée et le phénotype n’est en rien comparable au syndrome développemental sévère des mutants ton1 ou fass dépourvus de PPB. De plus, les plans de division ne sont pas aléatoires comme c’est le cas pour les mutants ton1 et fass. Nos résultats permettent donc d'apporter une nouvelle lumière sur le rôle de la PPB dans la détermination du plan de division. Pour la première fois, grâce au triple mutant trm6 trm7 trm8, nous avons réussi à découpler les fonctions interphasiques de la fonction mitotique du complexe TTP, ce qui était jusqu’alors impossible chez les mutants ton1 ou fass où les défauts en interphase et les défauts dus à l’absence de PPB étaient indissociables. Tous les composants du complexe TTP partageant des similarités avec des protéines centrosomales animales faisant partie du même complexe, nous avons exploré dans un projet annexe, la conservation des interactions au sein du complexe animal. Nous avons pu mettre en évidence, grâce au système double-hybride chez la levure, des interactions entre protéines animales et protéines végétalesPlant cells are embedded within a semi-rigid pecto-cellulosic cell wall that prevents cell migration. As a consequence, three-dimensional cellular organization of tissues mostly results from polarized cell division, since new cells remain in place after mitosis with no possibility for subsequent relocation. In land plants, the division plane is determined pre-mitotically, during the G2 to M phase transition by the preprophase band (PPB), a transient, premitotic microtubule array. The molecular pathways leading to preprophase band formation are still largely unknown. Our team has identified a regulatory complex, the TTP complex, composed of TON1, TRM and a Protein Phosphatase 2A complex with FASS as the regulatory subunit. Both TON1 and FASS have been shown to be involved in cortical microtubules organization during both interphase and PPB formation. The TRM super family is a newly identified protein family composed of 34 members, some of which are microtubule-associated proteins able to recruit TON1 and FASS to the microtubules. Based on TRM expression profiles and preliminary genetic analysis, we hypothesized that some TRMs could have a role in interphase, while others could be involved in PPB formation. My project was to identify and characterize TRMs specifically involved in PPB formation, if any. Transcriptomic analysis using the Genevestigator tool revealed that one TRM gene, TRM7, has a peak of expression at mitosis. TRM7 promoter GUS fusion analysis confirmed that TRM7 is expressed in all dividing tissues and in situ hybridizations of shoot apical meristems revealed a patchy pattern of expression, typical of cell cycle-regulated genes. Remarkably, the genomic TRM7-3xYFP fusion is only expressed at the G2/M transition where it localizes to the PPB, persists beyond PPB degradation until the beginning of metaphase and then disappears. To our knowledge, this makes TRM7 the only PPB-specific marker identified in plants so far, since all other PPB-associated markers label others structures as well, both interphasic or mitotic. TRM7 is part of the TRM6-7-8 sub-family, which share 74% of similarity. Phenotypic analysis of the trm7 and trm6 trm7 trm8 triple mutant revealed a major role of this sub-group in PPB formation. Almost half trm7 cells and all trm6 trm7 trm8 cells displayed an abnormal preprophase stage, the vast majority of the triple mutant cells dividing without PPB. Surprisingly, the triple mutant phenotype is rather mild compare to the severe developmental syndrome of PPB-lacking ton1 or fass plants. Moreover, although often shifted, division plane positioning is far from being fully randomized as in ton1 and fass mutants. Our results show that, for the first time, we have fully uncoupled the mitotic function of the TTP complex from its interphasic function, contrarily to other TTP mutants analyzed so far, where division and interphase defects are indistinguishable. Moreover, these findings question the central role of the PPB in division plane positioning. All TTP components share similarities with animal proteins assembled within a complex at the centrosome. In a side project, we studied the conservation of protein interactions within the animal complex and were able to find cross-interactions between animal and plant proteins in yeast two-hybrid experiments
2
(UPC), Universidad Peruana de Ciencias Aplicadas. "Taller de comunicación interpersonal - TR94 TR94." Universidad Peruana de Ciencias Aplicadas (UPC), 2018. http://hdl.handle.net/10757/623650.
Full textAbstract:
El Taller de Comunicación Interpersonal es el segundo de los talleres de la competencia de Habilidades
Interpersonales en la carrera de Traducción e Interpretación Profesional. Desarrolla de manera amplia y
dinámica el conocimiento y la reflexión personal sobre el proceso de comunicación y los diferentes aspectos
que se deben tener en cuenta para lograr la transmisión efectiva de un mensaje así como el logro de un propósito
específico. La comunicación efectiva es una herramienta crucial en el desarrollo de todo profesional y, más aún,
de los traductores e intérpretes.
El Taller de Comunicación Interpersonal es un espacio de exploración y reconocimiento de las capacidades
comunicacionales como traductor-intérprete, en el que el alumno identifica sus fortalezas y debilidades en el
área comunicativa, y aplica herramientas y estrategias para desarrollarlas y reforzarlas. Este taller tiene como
requisito el Taller de Liderazgo Personal y contribuye con el desarrollo del nivel 2 de la competencia general de
Comunicación Oral, y el nivel 1 de la competencia Pensamiento Innovador.
3
(UPC), Universidad Peruana de Ciencias Aplicadas, and Trierweiller Ana Claudia Rocker. "Portugués ti2 - TR84 201801." Universidad Peruana de Ciencias Aplicadas (UPC), 2018. http://hdl.handle.net/10757/623624.
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El curso Portugués TI2 es el segundo contacto del estudiante del programa de Traducción e Interpretación con
la segunda lengua electiva que desarrolla las habilidades comunicativas y lingüísticas del estudiante a través de
temas cotidianos, de baja complejidad, acorde con el conocimiento del usuario de la lengua meta en este nivel.
Representa el segundo nivel para la adquisición del idioma portugués que le permitirá, a futuro, ser un mediador
lingüístico y cultural efectivo para abordar problemáticas, crear acuerdos e implementar soluciones de manera
inmediata en dicho idioma. La temática del curso gira en torno de asuntos relacionados a la vida cotidiana, los
cuales son abordados a través de un lenguaje básico y en un nivel incipiente de conocimiento del idioma.
El curso Portugués TI2 ha sido diseñado para que el estudiante desarrolle las cuatro habilidades requeridas en
este idioma: comprensión oral, comprensión de lectura, expresión oral y producción de textos, en el nivel A2
según el Marco Común Europeo de Referencia para las Lenguas. Al trabajar con las competencias generales
UPC de Comunicación Oral, Comunicación Escrita, a un nivel 1 y con las competencias específicas de
Segundas Lenguas de la carrera, a un nivel 1, brinda al futuro traductor-intérprete una herramienta de
continuidad en la adquisición del idioma portugués para desarrollarse en su campo profesional con eficiencia. El
curso Portugués TI 2 tiene como prerrequisito el curso Portugués TI 1.
4
(UPC), Universidad Peruana de Ciencias Aplicadas, Morris Carlos Gerardo Delgado, Salazar Elena Olga Romero, Chumbez Maria Del Rosario Salcedo, and Diez Luis Ramón Sandoval. "Taller de comunicación interpersonal - TR94 201801." Universidad Peruana de Ciencias Aplicadas (UPC), 2018. http://hdl.handle.net/10757/623651.
Full textAbstract:
El Taller de Comunicación Interpersonal es el segundo de los talleres de la competencia de Habilidades
Interpersonales en la carrera de Traducción e Interpretación Profesional. Desarrolla de manera amplia y
dinámica el conocimiento y la reflexión personal sobre el proceso de comunicación y los diferentes aspectos
que se deben tener en cuenta para lograr la transmisión efectiva de un mensaje así como el logro de un propósito
específico. La comunicación efectiva es una herramienta crucial en el desarrollo de todo profesional y, más aún,
de los traductores e intérpretes.
El Taller de Comunicación Interpersonal es un espacio de exploración y reconocimiento de las capacidades
comunicacionales como traductor-intérprete, en el que el alumno identifica sus fortalezas y debilidades en el
área comunicativa, y aplica herramientas y estrategias para desarrollarlas y reforzarlas. Este taller tiene como
requisito el Taller de Liderazgo Personal y contribuye con el desarrollo del nivel 2 de la competencia general de
Comunicación Oral, y el nivel 1 de la competencia Pensamiento Innovador.
5
Pleshe, Elizabeth Lei. "Investigation of ligand binding Aquifex aeolicus TrmH." Diss., Connect to online resource, 2005. http://wwwlib.umi.com/cr/colorado/fullcit?p1427768.
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Hamidi, Zohal. "Characterization and Crystallization of the Mycobacterium Tuberculosis trmD." VCU Scholars Compass, 2010. http://scholarscompass.vcu.edu/etd/2219.
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One third of the world’s population is affected by Tuberculosis (TB), a disease caused by infection with Mycobacterium tuberculosis (MtB). The emergence of multidrug-resistant MtB makes this disease a major public health concern. New agents are needed to treat TB infections in a manner that circumvents existing pathways of resistance. One strategy is to target the organism at the translational level by inhibiting vital modifications of RNA. One gene responsible for these modifications is the tRNA (guanosine-1)-methyltransferase, trmD, which has been shown to be essential in several bacteria. The eukaryotic and bacterial m1G methyltransferases are structurally dissimilar, making this enzyme an ideal target for selective anti-TB agents. One strategy for TrmD inhibitor design is to target the catalytic center of the enzyme. Existing inhibitors such as Sinefungin exhibit poor selectivity due to the substrate’s role, SAM, as a universal methyl donor in many biological processes. Structure/activity relationships for inhibitory compounds are sparse, impeding the design of novel antimicrobials. Crystallographic data would identify molecular features unique to TrmD, and allow design of agents complimentary to the TrmD active site with minimal differential toxicity. Presently, no crystal structure for Mycobacterium tuberculosis TrmD exists. As a first step in this direction, the MtB gene has been cloned and expressed by using a His-tagged T7 expression vector. The recombinant protein was characterized through kinetic and preliminary inhibitor assays. The native enzyme displays a mass of 50 kDa, proving this enzyme is a dimer of two identical subunits. This is similar to data found on other TrmD orthologs. Crystallization of MtB TrmD has been achieved and preliminary x-ray diffraction studies conducted.
7
Barbet, Gaëtan. "Rôle du canal ionique TRPM4 dans les cellules dendritiques." Paris 7, 2009. http://www.theses.fr/2009PA077114.
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Les cellules dendritiques (DC) sont des cellules centrales du système immunitaire. Elles activent les lymphocytes et permettent l'orientation de la réponse immune adaptative. Pour cela, les DC doivent maturer et migrer vers les organes lymphoïdes secondaires, lieus de la mise en place d'une réponse lymphocytaire spécifique de l'agent infectieux. Le calcium est un second messager ubiquitaire régulant de nombreuses fonctions cellulaires dont la migration. Cependant, le rôle du calcium dans la biologie des cellules dendritiques a été relativement peu étudié. Nous montrons que le canal ionique TRPM4 est un acteur majeur de la régulation de l'homéostasie du calcium des DC après activation. En effet, l'absence de TRPM4 dans les DC induit une surcharge calcique après activation bactérienne ce qui affecte fortement la migration des DC sans affecter leur maturation. Nous avons observé qu'une surcharge calcique entraînait une diminution de l'expression de la PLC-p2 ce qui est corrélé à une absence de réponse lors d'une seconde stimulation calcique. Ainsi, ces travaux nous ont permis de montrer que TRPM4 est essentiel à la régulation de la migration et non de la maturation des DC renforçant l'idée selon laquelle ces deux entités biologiques sont régulées différemment. Un substrat artificiel des serines protéine-kinases F a-caséine et une protéine cytoplasmique de poids moléculaire de 65 kDa et de pH isoélectrique de 6,8Dendritic cells (DC) are central cells in immune System. DCs lead to lymphocyte activation and control adaptative immune response. To do so, DCs have to maturate and migrate toward secondary lymphoid organs where they initiate pathogen-specific lymphocyte responses. Calcium is an ubiquitous second messenger controlling a variety of cellular functions such as migration. However, the role of calcium in dendritic cells biology is poorly understood. We show that the ionic channel TRPM4 has a crucial role in calcium homeostasis in DC during stimulation. The lack of TRPM4 in DC leads to calcium overload after bacterial stimulation and dramatically decrease their migratory capacities but without affecting their maturation. We observed that a calcium overload leads to a decrease of the PLC-p2 expression which is correlated with an absence of a subsequent signalling response. Thus, this work shows the key rôle of TRPM4 in the migration but not the maturation of DC, emphasizing that these two cellular events are regulated differently
8
Uzzell, Jamar. "STRUCTURAL BASIS FOR THERMAL STABILITY OF THERMOPHILIC TRMD PROTEINS." VCU Scholars Compass, 2011. http://scholarscompass.vcu.edu/etd/2539.
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Thermal stability of theG37 tRNA methyltransferase proteins from Thermotoga maritima and Aquifex aeolicus have been compared using Differential Scanning Calorimetry. It was shown that the Thermotoga protein is remarkably stable and is denatured at temperatures in excess of 100 degrees Centigrade. The Aquifex aeolicus protein was less stable, denaturing broadly at temperatures between 55oC and 100oC. In contrast, the mesophilic E. coli protein was completely denatured at 55oC. Enzymatic activity of the proteins was measured at various temperatures. Both the Thermotoga and Aquifex enzymes are active at ambient temperatures, and display a significant decrease in activity when the temperature is raised above 50oC. This may relate to subtle changes in protein structure causing an effect on the tRNA based assay. Both enzymes contain inter subunit disulfide bonds which might contribute to thermal stability. Assays of the enzymes in the presence of high concentrations of Dithiothreitol (DTT) did not significantly reduce activity at higher temperatures, but did stimulate activity at lower temperatures. Site directed mutagenesis of non -conserved protein sequences within Thermotoga maritima were initiated in order to determine what structures might confer heat stability on the protein. Alanine mutagenesis of lysine residues 103,104 led to reduced catalytic activity, but did increased activity at higher temperatures. Aspartate is the most common residue at the relative position 166 in the variable loop of most TrmD genes. It has been shown that in E. coli this is essential for catalytic activity and possibly the residue which carries out N1 deprotonation on residue G37 in tRNA. In Thermotoga glutamate is present at this position. Alanine mutagenesis of this residue did not eliminate activity suggesting another nearby residue may function in this capacity in the Thermotoga TrmD protein.
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Furter, Rolf. "Das TRP4-Gen von Saccharomyces cerevisiae : Klonierung, Struktur und Regulation /." Zürich, 1986. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=7977.
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De, Marchi Carlo. "Probabilistic Estimation of Precipitation Combining Geostationary and TRMM Satellite Data." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/14068.
Full textAbstract:
Environmental satellites represent an economic and easily accessible monitoring means for a plethora of environmental variables, the most important of which is arguably precipitation. While precipitation can also be measured by conventional rain gages and radar, in most world regions, satellites provide the only reliable and sustainable monitoring system. This thesis presents a methodology for estimating precipitation using information from the satellite-borne precipitation radar of the Tropical Rainfall Measurement Mission (TRMM). The methodology combines the precise, but infrequent, TRMM data with the infrared (IR) and visible (VIS) images continuously produced by geostationary satellites to provide precipitation estimates at a variety of temporal and spatial scales. The method is based on detecting IR patterns associated with convective storms and characterizing their evolution phases. Precipitation rates are then estimated for each phase based on IR, VIS, and terrain information. This approach improves the integration of TRMM precipitation rates and IR/VIS data by differentiating major storms from smaller events and noise, and by separating the distinct precipitation regimes associated with each storm phase. Further, the methodology explicitly quantifies the uncertainty of the precipitation estimates by computing their full probability distributions instead of just single optimal values. Temporal and spatial autocorrelation of precipitation are fully accounted for by using spatially optimal estimator methods (kriging), allowing to correctly assess precipitation uncertainty over different spatial and temporal scales. This approach is tested in the Lake Victoria basin over the period 1996-1998 against precipitation data from more than one hundred rain gages representing a variety of precipitation regimes. The precipitation estimates were shown to exhibit much lower bias and better correlation with ground data than commonly used methods. Furthermore, the approach reliably reproduced the variability of precipitation over a range of temporal and spatial scales.
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Wu, Qiaoyan. "Diurnal variation of tropical precipitation using five years TRMM data." Texas A&M University, 2004. http://hdl.handle.net/1969.1/1266.
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The tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) and Precipitation
Radar (PR) data are used in this study to reveal diurnal variations of precipitation
over the Tropics (30◦S − 30◦N) from January, 1998, to December 2002. The TMI data
were used for the regions over oceans and islands and the PR data was used over continents.
The observations are sorted regionally to examine the difference in diurnal cycle of rainfall
over ocean, island, and continental regions. The rain rate is averaged over individual two
hour intervals of local time in each region to include more observations in order to reduce
the sampling error. F-test is used to determine those regions whose diurnal cycle is detected
at the 95% confidence level.
In most oceanic regions there is a maximum at 0400 LST - 0700 LST. The amplitude
of diurnal variation over ocean regions with small total rain is a little higher than that of
the ocean regions with heavy total rain. The diurnal cycle peaks at 0700 LST - 0800 LST
over islands with rainfall variation similar to surrounding oceanic regions. A maximum
at 1400 LST - 1500 LST was found in areas over continents with heavy total rain, while
the maximum occured at 1900 LST - 2100 LST over continents with lesser total rain. The
amplitudes of variation over continents with heavy total rain and with small total rain do
not show significant differences. The diurnal cycle in in JJA (June, July, August) and DJF
(December, January, February) varies with latitude over continents. A seasonal cycle of
diurnal cycle can also be found in some oceanic regions. The diurnal cycle annual change
is not evident over continents, while the diurnal cycle annual change over oceans exists in
some regions. Island regions in this paper exhibit no evident seasonal and annual diurnal
change.
12
CAMPOS, R. F. "Comparação entre dados de precipitação interpolados e do TRMM (3B43V7)." Universidade Federal do Espírito Santo, 2017. http://repositorio.ufes.br/handle/10/7592.
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Previous issue date: 2017-02-20As estimativas de precipitação do satélite TRMM (Tropical Rainfall Measuring Mission) podem ser informações valiosas para áreas sem quaisquer tipos de medições da pluviosidade ou regiões com uma rede pluviométrica escassa. O objetivo do estudo foi comparar as estimativas mensais de precipitação do satélite TRMM com dados de precipitação terrestre interpolados produzidos por Xavier et al. (2015) para o Brasil. Para quantificar a concordância e parecença entre os bancos de dados foi utilizado o índice de concordância refinado de Willmout e o índice de desempenho. Os resultados indicaram que o satélite capturou adequadamente os padrões espaciais de precipitação em todo o Brasil quando comparado com a estimativa interpolada. É importante ressaltar que o satélite TRMM tendeu a superestimar os valores de precipitação, entretanto em média o acordo entre as estimativas TRMM e os dados DPTI é alto (dr ≥0,8 e Pi ≥0,7), mas observa-se maior viés em épocas chuvosas. Com base nestes resultados, a região Norte apresentou resultados mais discordantes para o Brasil. Esta região foi escolhida para o cálculo do índice de erosividade com o objetivo de visualizar a diferença da entrada dos dados interpolados com os dados do satélite TRMM no cálculo da erosividade. Os dados do satélite TRMM apresentaram menor índice de erosividade para região Norte. Isto significa que a erosividade com dados interpolados pode superestimar o real valor da erosividade nesta região, devido a limitações, como a escassa rede pluviométrica, inerentes ao banco de dados de estações interpoladas para esta região. Palavras-chave: Sensoriamento Remoto, Estatística Descritiva, Análise de concordância.
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GAMA, Nicolas Alexandre. "Validação das estimativas de precipitação observadas pelo Tropical Rainfall Measuring Mission para o Brasil." Universidade Federal de Pernambuco, 2016. https://repositorio.ufpe.br/handle/123456789/18868.
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Gama, N.A. (2016) - Validação das Estimativas de Precipitação Observadas pelo Tropical Rainfall Measuring Mission para o ~1.pdf: 9989783 bytes, checksum: cbd93ee88254c673fdb01934acc83002 (MD5)Made available in DSpace on 2017-05-23T15:38:53Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Gama, N.A. (2016) - Validação das Estimativas de Precipitação Observadas pelo Tropical Rainfall Measuring Mission para o ~1.pdf: 9989783 bytes, checksum: cbd93ee88254c673fdb01934acc83002 (MD5) Previous issue date: 2016-03-11
CAPES
A precipitação é considerada um elemento fundamental e de grande importância no ciclo hidrológico, pois é através dela que é feita a recarga hídrica nas bacias hidrográficas e nas reservas subterrâneas.O monitoramento meteorológico é de grande importância para as nações, este monitoramento pode ser feito através de diversos métodos e instrumentos, sejam eles terrestres ou orbitais. No Brasil problemas relacionados à seca tornam-se preocupantes e estão presentes na sociedade moderna. O estudo e entendimento de comportamentos de padrões espaciais de informações sobre precipitações é uma ferramenta importante para a tomada de decisão. Observações obtidas por sensores a bordo de satélites artificiais na órbita da Terra auxiliam na medição do volume de chuva em uma dada região. Para esta dissertação foram utilizados como materiais um conjunto de dados gratuitos de precipitação do TRMM (TROPICAL RAINFALL MEASURING MISSION) através de um dos seus produtos disponíveis chamado de Rainfall Product (3B43). Atualmente estes recursos vêm sendo utilizado em diversas pesquisas onde entre suas vantagens encontram-se: a periodicidade de amostragem (resolução temporal) e abrangência superior às estações meteorológicas. Porém, as observações dos sensores orbitais apresentam algumas desvantagens como, por exemplo, a resolução espacial da informação da precipitação, sendo recomendado estabelecer critérios para as análises e validação das estimativas. Sendo assim, além de dados orbitais, informações sobre séries históricas de precipitação obtidas por estações meteorológicas que são operados por diversos órgãos públicos foram utilizadas. Desta forma, foram delineados objetivos para essa pesquisa sendo eles: (i) avaliar os dados do TRMM, a fim de valida-los como um instrumento de monitoramento de precipitação para o Brasil; (ii) comparar as informações históricas do TRMM as respectivas estações de campo em amostras no território brasileiro e assim determinar a correlação entre estes produtos; (iii) Avaliar os dados TRMM de precipitação com base no período de 2000 até 2014 aplicando um teste de normalidade a fim de verificar regiões onde existe maior igualdade estatística entre os produtos. Para a avaliação e validação dos dados do produto TRMM 3B43 em relação às séries históricas das estações meteorológicas, foram feitas análises estatísticas como a correlação entre os dados e o teste de Kolmogorov-Smirnov entre as duas Grades de informações. Espera-se através desta pesquisa contribuir com o uso e divulgação de informações temporais do TRMM para o monitoramento de precipitação no território brasileiro. Através da análise estatística entre os dois conjuntos de dados, percebeu-se que há sim a possibilidade de utilização dos dados do satélite TRMM para verificar o comportamento das curvas de precipitação, contribuindo ainda mais em regiões onde há escassez de dados in situ como o caso da região Amazônica.
Meteorological monitoring is considered very important to the nations, andthis can be done through various methods and instruments, among them are the terrestrial and orbital. In Brazil droughtrelated problems become worrisome and are present in modern society.The study and understanding of behaviors of spatial patterns about precipitations is an important tool for decision making. Observations obtained by remote sensingusing artificial satellites can give support for mesuring rainfall in a given region. The materials used in this work was a set of free rainfall data from TRMM (Tropical Rainfall Measuring Mission) considering Rainfall Product (3B43). Nowawadaysthese resources have been used in several researches presenting some advantges and between these are: sampling frequency (temporal resolution) and higher coverage compared to the insitu stations. However, there are some disadvantages, for e.g., the rainfall spatial resolution and the requirement to establish some criteria for analysis and data validatiing. Therefore, in addition to orbital data, information on historical precipitation series obtained by insitu stations that are operated by public organizations has been used. Thus, goals have been set for this research which are: (i) evaluate the TRMM data in order to validate it as a rainfall monitoring instrument for Brazil; (ii) obtain satellite TRMM historic information and in situ rainfall stations over Brazil and determine the correlation between these products; (iii) evaluate TRMM records of precipitation based during 2000 until 2014 period, and applying on them a normality test to verify regions where there is more statistical equality between the products. For the evaluation and validation of TRMM 3B43 product data in relation to historical series from in situ stations, statistical analyzes were made as the correlation between the observations using the Kolmogorov-Smirnov test between the two Grids information. It is expected through this research to contribute to the use and disclosure of TRMM temporal information for rainfall monitoring in Brazil. Through statistical analysis of the two sets of data, it was realized that there is the possibility of using the TRMM satellite data to verify the behavior of precipitation curves, further contributing in areas where there are few data in situ as the case of the Amazon region.
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Ferreira, Franck. "Exploitation des données du radar de TRMM pour l'estimation de la pluie depuis l'espace." Paris 6, 2001. http://www.theses.fr/2001PA066089.
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Sanderson, Victoria Louise. "An evaluation of TRMM satellite rainfall climatologies : implications for climate studies." Thesis, University of Birmingham, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.403605.
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This thesis assesses regional and temporal dependent biases in several microwave rainfall climatologies and considers their implications for monitoring the El Nino Southern Oscillation. Seasonal rainfall climatologies from the Tropical Rainfall Measuring Mission (TRMM) are evaluated during the transition from the 1997/1998 El Nino to the 1998/2000 La Nina. The satellite algorithms include version 5 TRMM rainfall products (GPROF (2A12), COMBINED (2B31) and PR (2A25», several passive microwave algorithms and GPCP (Global Precipitation Climatology Project) satellite-gauge estimates. All are compared to GPCC (Global Precipitation Climatology Centre) gauge estimates and two benchmark climatologies. The passive microwave algorithms are spatially and temporally calibrated to the Precipitation Radar using the histogram matching approach, which minimises spatial and temporal algorithm biases. Each algorithm detects seasonal and inter-annual variations in the rainfall distributions, although absolute values are shown to be significantly different. Despite three year quasiglobal averages converging to within -20%, zonal averages show large variations in the magnitude of the biases, e.g. >55% (-30%) for the austral (boreal) summer over land and >40% (-20-25%) during El Nifio (La Nina) over the ocean. Fine-scale comparisons show regional differences vary from <20% to >200%. Biases are attributed to variations in cloud microphysical characteristics, sampling problems and passive microwave coastal and surface artefacts. Unless temporal and spatial algorithm biases are accounted for, all satellite retrievals should be restricted to qualitative assessments of climatic rainfall.
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Gopalan, Kaushik. "A TIME-VARYING RADIOMETRIC BIAS CORRECTION FOR THE TRMM MICROWAVE IMAGER." Doctoral diss., University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2435.
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This dissertation provides a robust radiometric calibration for the TRMM Microwave Imager to correct systematic brightness temperature errors, which vary dynamically with orbit position (time) and day of the year. The presence of a time-varying bias in TMI is confirmed by inter-calibration with WindSat and SSMI. This time varying bias is manifested as a time of day dependent variation of the relative biases between TMI and both WindSat and SSMI. In this dissertation, we provide convincing evidence that this time-varying Tb bias in TMI is caused by variations in the physical temperature of the emissive TMI reflector antenna. This dissertation provides an empirical correction that largely corrects this time-varying bias. The TMI bias is estimated by comparing the 10.7 GHz V-polarization channel observations with RTM Tb predictions, and the Tb correction is applied as a function of orbit time for every day of the one year period. Furthermore, this dissertation provides a qualitative physical basis for the estimated Tb bias patterns and provides conclusive evidence that the empirical correction applied to TMI Tb measurements (both ocean and land) largely corrects the time-varying TMI calibration. This is accomplished by demonstrating that the local time-of-day dependence (in the uncorrected TMI Tb values) is removed in the corrected TMI Tb's.Ph.D.
School of Electrical Engineering and Computer Science
Engineering and Computer Science
Electrical Engineering PhD
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Gueffier, Mélanie. "Rôle du canal TRPM4 dans l'hypertrophie cardiaque : utilisation d'un modèle d'entraînement." Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTT035.
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Le muscle cardiaque est un organe qui s'adapte à différents stress hémodynamiques en activant la synthèse protéique et en augmentant la taille des cardiomyocytes, résultant sur le développement d'une hypertrophie cardiaque. L'objectif de cette thèse est d'étudier le rôle potentiel du canal TRPM4 dans différents types d'hypertrophie cardiaque. Une altération du Ca2+ diastolique est à l'origine du signal initial activant les voies de signalisation d'une hypertrophie cardiaque délétère de type pathologique telle que la voie de la calcineurine-NFAT et la ré-expression de gènes fœtaux. Cette hypertrophie est alors compensatrice et vise à préserver la fonction de pompe du myocarde. Cette altération peut être conduite par divers stimulis tels qu'une augmentation de l'angiotensine II ou par des pathologies cardiovasculaires telles que l'infarctus du myocarde et l'hypertension. Cependant, une hypertrophie cardiaque bénéfique est également décrite dans la littérature, notamment lors des stades de développement du myocarde lors de l'embryogénèse ou en encore en réponse à une activité physique modérée régulière. Elle se caractérise par l'activation d'une toute autre voie de signalisation qu'est la voie de l'IGF-1-PI3K-Akt engendrée par une augmentation du taux de facteur de croissance qu'est l'insulin growth factor-1. Ces voies de signalisation ont été largement décrites dans la littérature et s'entrecroisent. Le canal TRPM4 est un canal cationique non sélectif perméable de manière égale aux ions Na+ et au K+, imperméables au Ca2+, mais activé par le Ca2+ intracellulaire. Dans le système immunitaire, il régule négativement l'entrée de Ca2+ et ce canal apparaît donc impliqué dans de nombreuses fonctions cellulaires dépendantes du Ca2+ dans différents types cellulaires. Par l'utilisation de deux modèles d'hypertrophie cardiaque, un physiologique généré par quatre semaines d'entraînement en endurance et un pathologique suite à un infarctus du myocarde induit par la ligature de l'artère coronaire gauche sur des souris wild-type et knock-out (KO) pour le canal TRPM4, nous avons mis en évidence une augmentation d'expression fonctionnelle du canal TRPM4 au sein du ventricule gauche associée à une régulation négative d'entrée de Ca2+. Le canal TRPM4 étant un régulateur de l'homéostasie calcique des cardiomyocytes, son expression fonctionelle après l'infarctus du myocarde ainsi que l'entraînement favorise l'activation de la voie de l'IGF-1-PI3K-Akt et prévient partiellement l'activation de la voie de la Calcineurine-NFAT et le développement d'une hypertrophie cardiaque pathologique, notamment dans le modèle d'infarctus du myocarde. En effet, en absence d'expression du canal, l'entrée de Ca2+ n'étant plus régulée, la voie de la Calcineurin-NFAT est favorisée. Mots clés : TRPM4, hypertrophie cardiaque, entraînement, IGF-1-PI3K-Akt, CalcineurineAbstract: Cardiac muscle is an organ that adapts to different hemodynamic stress by activating protein synthesis and increasing cardiomyocytes size, resulting in cardiac hypertrophy. The objective of this PhD is to study the potential role of TRPM4 channel in different types of cardiac hypertrophy. Impaired diastolic Ca2+ is responsible for the initial signal activating signaling pathways in a deleterious cardiac hypertrophy pathological type such as Calcineurin-NFAT pathway and the re-expression of fetal genes. This hypertrophy is first compensatory and preserves the myocardial pump function. This alteration can be carried out by various stimuli such as increased angiotensin II or by cardiovascular diseases such as myocardial infarction and hypertension.However, a beneficial cardiac hypertrophy is also described in the literature, especially during development stages during embryogenesis or even in response to regular moderate physical activity. It is characterized by the activation one different signaling pathway, the IGF-1 - PI3K –Akt, generated by an increase in growth factor levels that is the insulin growth factor -1. These signaling pathways have been widely described in the literature and cross-talking. TRPM4 channel is a nonselective cation channel permeable equally to Na+ and K+, impermeable to Ca2+ but activated by the intracellular Ca2+. In the immune system, it downregulates Ca2+ entry and therefore appears to be involve in many Ca2+-dependent cellular functions in different cell types. By the use of two models of cardiac hypertrophy, a physiological generated by four weeks of training in endurance and pathological after myocardial infarction induced by ligation of the left coronary artery on wild-type and knockout mice -out (KO) for TRPM4 channel, we have demonstrated a functional expression increased TRPM4 channel within the left ventricle associated with down-regulation of Ca2 + entry. TRPM4 the channel being a regulator of calcium homeostasis in cardiomyocytes functional expression after myocardial infarction as well as the drive promotes the activation of the pathway of IGF-1-PI3K-Akt and partially prevents the pathway activation of the NFAT-calcineurin and the development of pathological cardiac hypertrophy, in particular myocardial infarction model. Indeed, in the absence of expression of the channel, the Ca2 + is not regulated, the path of Calcineurin-NFAT is favored. Keywords: TRPM4, cardiac hypertrophy, training, IGF-1-PI3K-Akt, calcineurin
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Collischonn, Bruno. "Uso de precipitação estimada pelo satélite TRMM em modelo hidrológico distribuído." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2006. http://hdl.handle.net/10183/7684.
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A precipitação é provavelmente a variável do ciclo hidrológico que apresenta a maior variabilidade espacial. Postos pluviométricos convencionais fornecem registros válidos apenas para um pequeno entorno do instrumento. A baixa densidade de postos pluviométricos em bacias brasileiras tem sido o fator determinante nas incertezas dos resultados de diversos modelos hidrológicos que têm sido aplicados no país. Nesse contexto, estimativas espaciais de precipitação podem constituir-se em uma ferramenta extremamente útil. Essas estimativas, embora pouco precisas quando comparadas com valores pontuais medidos no solo, fornecem uma boa noção da distribuição espacial das chuvas. Neste trabalho, avalia-se em que medida as estimativas de precipitação obtidas a partir do satélite TRMM podem ser úteis quando usadas como dado de entrada do modelo hidrológico distribuído MGB-IPH, sozinhas ou associadas com os dados da rede pluviométrica. Os resultados são analisados em termos de vazão simulada, considerando que esta representa a integração de todos os fenômenos hidrológicos na bacia. Foram realizados estudos de caso na bacia do rio São Francisco até a UHE Três Marias, que conta com boa rede pluviométrica para aferir as estimativas, e na bacia do rio Tapajós, que possui baixa densidade de postos pluviométricos. O modelo alternativo, usado com estimativas de satélite, teve desempenho pouco inferior ou mesmo similar ao modelo convencional, usado com dados de pluviômetros. Além disso, os campos de precipitação obtidos por satélite são potenciais ferramentas para consistência de dados pluviométricos em escala de bacia hidrográfica e estimativa da precipitação em áreas com deficiente rede pluviométrica, considerando que os resultados obtidos pela rede e por satélites mostraram valores próximos.
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Simard, Christophe. "Implication du canal cationique non-sélectif TRPM4 dans l'activité électrique cardiaque." Caen, 2012. http://www.theses.fr/2012CAEN3144.
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La protéine TRPM4 porte un courant cationique non-sélectif activé par le calcium intracellulaire (NSCCa). Au niveau cardiaque, il est présent sur l’oreillette (humain, rat et souris) et dans le noeud sinusal (souris), mais peu exprimé au niveau ventriculaire. Toutefois son expression ventriculaire est augmentée en cas d’hypertrophie cardiaque. Malgré une cartographie bien établie l’implication de TRPM4 dans l’activité électrique cardiaque était jusqu’à aujourd’hui inconnue. Ce travail de thèse a eu pour objectif d’évaluer l’implication du canal TRPM4 dans l’activité cardiaque, en utilisant des techniques d’électrophysiologie. Nous avons combiné une approche pharmacologique, utilisant les inhibiteurs du TRPM4 et une approche de transgénèse, en utilisant des souris invalidées pour le gène TRPM4. Nous avons observé que le canal TRPM4 est impliqué dans la durée du potentiel d’action de l’oreillette de souris, puisque son inhibition diminue la durée du PA, et que les souris invalidées pour le gène TRPM4 présentent un PA plus court que les souris sauvages. Le canal participe également à certaines formes d’arythmies ventriculaires. Nous avons développé un modèle d’arythmies d’hypoxie-réoxygénation sur du ventricule de souris, où l’application des inhibiteurs du TRPM4 conduit à la disparition de ces arythmies. Enfin nous avons établi un lien entre des mutations du gène TRPM4 et le syndrome de Brugada. En particulier, une mutation K914X aboutissant à un canal non fonctionnel, a été identifiée chez un malade atteint du syndrome de Brugada. L’ensemble de nos travaux identifiant, le TRPM4 comme une nouvelle cible pharmacologique dans la prévention des troubles du rythme cardiaqueThe TRPM4 protein, is a member of the larger family "Transient Receptor Potentiel" channels, and supports a nonselective cationique current activated by intracellular calcium (NSCCa). TRPM4 presents a large tissular distribution. In the heart, it is present in the atrium (human, rat and mouse) and sinus node (mouse), but it is only slightly expressed in the ventricle. However its ventricular expression is increased in case of cardiac hypertrophy (SHR rat). While TRPM4 cardiac mapping is well established, its implication in the cardiac activity was still unknown. Our work had for objective to estimate the implication of the TRPM4 channel in the cardiac activity, by using electrophysiological technics (intracellular microelectrode and patch-clamp). We combined a pharmacological approach, using two inhibitors of the TRPM4 (the acid flufénamique and 9-phénanthrol) and an approach of transgenesis, by using mice invalidated for the TRPM4 gene. We observed that TRPM is implied in the mice atrial action potential duration (APD), because its inhibition decreases the APD, and TRPM4-/-transgenics mice present a shorter AP than TRPM4+/+ mice. TRPM4 channel also participates in ventricular arrhythmias. We developed a model of hypoxia-reoxygenation to produce arrhythmias. The application of TRPM4 inhibitors eliminates these arrhythmias. Finally we established a link between TRPM4 mutations and Brugada syndrome. In particular, the mutation K914X giving an unfunctional channel, was identified in a patient affected by Brugada Syndrome. Our study identifies, TRPM4 as a new promising pharmacological target in the prevention of cardiac electrical disturbance
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Nascimento, Diego Tarley Ferreira. "Chuvas no estado de Goiás e no Distrito Federal a partir de estimativas por satélite e circulação atmosférica." Universidade Federal de Goiás, 2016. http://repositorio.bc.ufg.br/tede/handle/tede/6023.
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Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq
Avec l'avènement des nouveaux capteurs et produits de télédétection, il existe la possibilité d'appliquer des images de satellite comme une alternative à une représentation cohérente du complexe climatique, à partir du point de départ pour une analyse de la continuité spatiale. Ainsi, cette thèse de doctorat vise à fournir une étude des pluies dans l'état de Goiás et au District fédéral, en profitant des estimations des précipitations par satellite. Les procédures méthodologiques inclus la définition des années établi (années-standart) comme d'échantillons du régime habituel et des précipitations exceptionnelles, et l'utilisation d'estimations mensuelles et quotidiennes des précipitations de Mission de Mesure de Pluies Tropical (Tropical Rainfall Measuring Mission - TRMM) à et l'étude de la pluviométrie, basée sur une analyse qualitative et quantitative des données les précipitations annuelles, saisonnières, mensuelles et journalières, avec l'identification des systèmes météorologiques actifs et responsables pour la formation de la pluie. La distribution spatiale des précipitations reflète l'influence des compartiments topographiques à l'entrée et le déplacement ou même comme un obstacle à l'avancement des systèmes atmosphériques qu’il sont producteurs de pluie dans la région. La variabilité de précipitations entre les différentes années établi conduit à comprendre que l'état de sèche, normale et humide ne fait pas référence à la hauteur annuelle des précipitations, mais, surtout, la distribution des précipitations au cours des mois et la délimitation de la saison des pluies et sec. En outre, il a été mis en exergue les différentes activités et la participation des masses d'air dans la genèse des pluies sur l ‘Etat de Goiás et le District fédéral, où normalement on voit une représentation équilibrée entre les principaux systèmes atmosphériques opérant dans la région, alors que le régime sec a augmenté les performances du mTa et le régime des pluies reflète la haute performance de mEc.
Com o advento de novos sensores e produtos do Sensoriamento Remoto, surge a possibilidade de aplicação de imagens satelitárias como alternativa para uma coerente representação do complexo climático, partindo do pontual para uma análise do contínuo espacial. Sendo assim, a presente tese de doutorado teve como objetivo geral prover um estudo das chuvas no estado de Goiás e no Distrito Federal, valendo-se de estimativas de precipitação realizadas por satélite e considerando a circulação atmosférica. Os procedimentos metodológicos compreenderam a definição de anos-padrão como recortes amostrais do regime habitual e excepcional das chuvas e o uso de estimativas mensais e diárias de precipitação do Tropical Rainfall Measuring Mission (TRMM) para o estudo das chuvas, amparada numa análise quali-quantitativa dos valores anuais, sazonais, mensais e diários de precipitação, com a identificação dos sistemas atmosféricos atuantes e responsáveis pela formação de chuvas. A distribuição espacial da precipitação refletiu a influência dos compartimentos topográficos na entrada e no deslocamento ou mesmo como barreira ao avanço dos sistemas atmosféricos produtores de chuva na região. A variabilidade da precipitação entre os diferentes anos-padrão leva a entender que a condição de seco, habitual e chuvoso não se refere essencialmente à altura pluviométrica anual, mas, sobretudo, à distribuição das chuvas no decorrer dos meses e à delimitação do período chuvoso e seco. Também foi posta em evidência as diferenças de atuação e participação das massas de ar na gênese das chuvas do estado de Goiás e do Distrito Federal, em que no regime habitual percebe-se uma atuação equilibrada entre os principais sistemas atmosféricos atuantes na região, ao passo que o regime seco apresenta aumento da atuação da massa tropical atlântica (mTa) e o regime chuvoso reflete elevação da atuação da massa equatorial continental (mEc).
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Nunes, Ana Maria Pereira. "Climatologia e ambiente de tempo severo na Amazônia." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/14/14133/tde-29052015-133627/.
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A região amazônica desempenha papel fundamental na regulação do clima, tanto em escala regional quanto em escala global. A precipitação na região é bastante heterogênea, sobretudo devido à vasta extensão territorial da Amazônia. Dentre os sistemas responsáveis pela precipitação, alguns se destacam como eventos extremos de tempestades, como pode ser verificado em diversos estudos anteriores. Contudo, diferentemente das latitudes médias, na região tropical não há um conjunto de definições amplamente conhecido e difundido para identificação de tempo severo. O presente estudo busca identificar um critério para identificação de tempo severo na região amazônica a partir da base de dados Precipitation Features (PF) 1998 a 2012 - gerados e armazenados pela Universidade de Utah, com base nos dados do satélite TRMM. Além disso, identificar características sinóticas associadas ao ambiente de ocorrência destes eventos, através de composições com dados da reanálise CFSR-NCEP, bem como parâmetros importantes na identificação de tempestades. Utilizando o subconjunto PCTF do Nível 2 da base de dados PF, o critério estabelecido para identificação de casos severos compreende sistemas com: 80 pixels ou mais PCT85 GHz <250 K; 1 pixel ou mais com PCT85 GHz < 100 K; volume de chuva convectiva maior do que 1000 mm/h km2 e pelo menos um registro de raio. Comparando os sistemas selecionados pelo critério com os Sistemas Convectivos de Mesoescala já catalogados é possível notar que a distribuição sazonal é semelhante, embora as estações com maior número de casos sejam as estações de transição (primavera e outono, 429 e 223 casos respectivamente). Analisando as altas taxas de raios destes sistemas, fica evidente que o critério realmente seleciona casos severos. Com a região amazônica dividida em seis sub-regiões e os casos acumulados por trimestre (JFM, AMJ, JAS, OND) sub-região Southern Amazonia (SA) contabiliza o maior número de casos, com um total de 271 para o período do estudo, sendo OND o trimestre com maior ocorrência (135), o menor AMJ (29). O mês de outubro chama atenção para esta sub-região como o mês com maior número de casos, totalizando 59, dos quais 83% ocorrem a partir das 12 horas local. Estes casos foram investigados nas composições de reanálise, assim como os casos a partir de 12 horas local de outubro da sub-região Central Amazonia (CA). De forma geral: 1) SA tem maior área com cisalhamento médio mais intenso (8 m/s) do que CA, principalmente para 00Z, 06Z e 12Z; 2) valores médios de divergência positiva do vento em 200 hPa mostram-se mais significativos para CA do que para SA; 3) convergência do vento em 950 hPa é mais evidente para SA do que para CA e 4) CA é predominantemente mais úmida em baixos níveis do que SA. Histogramas com valores pontuais para cada um destes casos, em ambas as sub-regiões, são apresentados no intuito de auxiliar a identificação destes casos por previsores. O critério de identificação de tempo severo na Amazônia mostra-se eficiente, sendo o cisalhamento do vento entre 500-850 hPa e a convergência do vento em 950 hPa os como parâmetros mais importantes na região SA, onde há maior ocorrência de tempestades severas.The Amazon region plays a key role in climate regulation, both at the regional scale and on a global scale. Rainfall in the region is very heterogeneous, mainly because of the vast size of the Amazon. Among the systems responsible for rainfall, some stand out as extreme storm events, as can be seen in many previous studies. However, unlike the mid-latitudes, in the tropical region there is no widely acknowledged set of conditions for severe weather identification. This study seeks to identify a criterion for identifying severe weather in the Amazon region from the database Precipitation Features (PF) - 1998-2012 - generated and stored by the University of Utah, based on the TRMM satellite data. This study will also attempt to identify synoptic features associated with the occurrence of these events through compositions using the reanalysis NCEP CFSR data. Using the PCTF subset of Level 2 of PF database, the criteria established for identifying severe cases include: 1) systems with 80 or more pixels PCT85 GHz <250 K; 2) systems with one or more pixel with PCT85 GHz <100 K; 3) systems with convective rain volume greater than 1000 km2 mm/h and 4) at least one record of lightning. Comparing the systems selected by this criterion with the Mesoscale Convective Systems already cataloged it can be seen that the seasonal distribution is similar, although the stations with the highest number of cases are the transition seasons (spring and fall, 429 and 223 cases, respectively). Analyzing high rates of rays found in these systems, it is clear that the criterion truly selects severe cases. With the Amazon region divided into six sub-regions and cases accumulated by quarter (JFM, AMJ, JAS, OND) South of the Amazon sub region (SA) accounts for the largest number of cases, with a total of 271 for the period of study, OND quarter with higher occurrence (135), the lowest AMJ (29). The month of October draws attention to this sub-region as the month with the highest number of cases, totaling 59, of which 83% occur after 12 local time. These cases have been investigated in compositions, as well as cases observed after 12 local time in October for Amazon Central subregion (CA). In general: 1) SA has larger area with average stronger shear (8 m/s) than AC, especially for 00Z, 06Z and 12Z; 2) average wind positive divergence values at 200 hPa were more significant for CA than for SA; 3) Wind convergence at 950 hPa is more obvious for SA than at CA and 4) is predominantly CA moster at low levels than SA. Histograms with specific values for each of these cases, both sub regions are presented in order to help identify predictors for these cases. The severe weather identification criterion in the Amazon proves efficient, while the wind shear between 500-850 hPa and wind convergence in 950 hPa stand out as important parameters in the SA region, where there is greater occurrence of severe storms.
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Tang, Yue-bun Alan, and 鄧裕斌. "Molecular and functional characterization of a testis-specific TRS4 gene in spermatogenesis." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B43572169.
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Yoshida, Marcos Cézar. "Estudo de células convectivas em Rondônia durante o experimento WETAMC-LBA/TRMM." Instituto Nacional de Pesquisas Espaciais, 2002. http://urlib.net/sid.inpe.br/iris@1905/2005/08.03.21.22.
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Este estudo analisa o comportamento tridimensional da chuva convectiva sobre o estado de Rondônia e imediações durante a primeira Wet Season Atmospheric Mesoscale Campaign (WETAMC) do Large Scale Biosphere-Atmosphere Experiment in Amazonia (LBA), em conjunto com a Tropical Rainfall Measuring Mission (TRMM), que foi realizado no período de janeiro e fevereiro de 1999. Foram utilizadas imagens do "Precipitation Radar" (PR) a bordo do satélite TRMM, radiosondagens atmosféricas realizadas na estação meteorológica do Rebio Jaru, imagens do Geostationary Operational Environmental Satellite-8 (GOES-8) e os campos de vento e umidade do National Center for Enviroment Predictions/National Center for Atmospheric Research (NCEP/NCAR). Nas análises do comportamento vertical das células convectivas, a partir de um critério de intensidade adotado, selecionaram-se apenas as tempestades maduras fortes e intensas, e obteve-se os perfis verticais médio zonal e médio meridional da taxa de precipitação. Definindo um critério de profundidade em relação aos perfis médios, as células convectivas foram classificadas em rasas, médias e profundas. Para analisar o comportamento horizontal das tempestades convectivas, observou-se o campo de chuva na região de Rondônia dentro do ciclo diurno em 3 subregiões. Adicionalmente, cada imagem foi identificada conforme a sua distribuição de células de chuva dentro da área precipitante em tempestades unicelulares, multicelulares e supercelulares. Combinando o comportamento horizontal e vertical da chuva convectiva, observou-se que os eventos multicelulares ocorrem com maior frequência (58,3%), seguido dos eventos unicelulares (25,0%) e supercelulares (16,7%). Destaca-se que nos eventos supercelulares a profundidade alcançada pelas células convectivas tende a ser menor do que a média. Nos eventos unicelulares e multicelulares as células convectivas apresentaram distribuições abaixo e acima da média. Um estudo de caso de uma tempestade supercelular ocorrida no norte de Rondônia no dia 25 de janeiro é apresentado. Neste caso, as análises do índice de levantamento (Li), do índice K (Ki), da energia potencial convectiva disponível (CAPE), da razão de mistura (r) e da temperatura potencial equivalente (_e) indicam que o evento ocorreu em um ambiente termodinamicamente favorável para desenvolvimento de sistemas convectivos.This study analyzes the three-dimensional behavior of the convective rain on the state of Rondônia and vicinity during the first Wet Season Atmospheric Mesoscale Campaign (WETAMC) of the Large Scale Biosphere-Atmosphere Experiment in Amazonia (LBA) and concomitantly with the validation of the Tropical Rainfall Measuring Mission (TRMM). The analysis was done from January to February, 1999 period. Rain images from the Precipitation Radar (PR) onboard of the TRMM satellite, Rebio Jaru radiosonde data, Geostationary Operational Environmental Satellite-8 (GOES-8) infrared images and National Center for Enviroment Predictions/National Center for Atmospheric Research(NCEP/NCAR) wind and humidity fields were used for characterizing the convective activity. In the analyses of the vertical behavior of convective cells, following an adopted intensity criterium, it was selected only the strong and intense cells in their mature stage to obtain the zonal and meridional average vertical profiles of rain. From the average profiles, the convective cells were classified as shallow, medium and deep. To analyze the horizontal distribution of the convective storms and the associated diurnal cycle of rainfall, the region Rondônia was subdivided in three subregions. Additionally, each rain event was classified as: singlecell, multicell and supercell storms. From the horizontal and vertical behavior of the convective storms, it was observed that the prevailing events are: multicells (58,3%), singlecells (25,0%) and supercells (16,7%). It stands out that in the case of supercells the convective depth tend to be shallow, while singlecells and multicells events are relatively well distributed between shallow and deep. A case study of a supercell storm occurred in northen Rondônia on the 25 of January was also analyzed. In this case, variables such as the lift index (Li), k index (Ki), convective available potential energy (CAPE), mixing rate (r) and the equivalent potential temperature (_e) indicate that the event occurred in an ambient thermodynamically favorable for the storm development.
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Soares, Alexleide Santana Diniz. "Avaliação das estimativas de chuva do satélite TRMM no estado da Paraíba." Universidade Federal da Paraíba, 2014. http://tede.biblioteca.ufpb.br:8080/handle/tede/5530.
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Previous issue date: 2014-05-15Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq
The spatial and temporal variability is a precipitation feature and constitutes a factor of complexity for developing rainfall studies. Moreover, the low density of rain gauge stations and errors in data collection in the field increase the difficulties in implementing studies in this research area. However, such researches are essential considering that it is from them that we can carry out flood and drought forecasts, understand the hydrological regime of rivers, soil moisture, temperature changes, among others. Thus, the spatial rainfall estimates obtained through satellites data are important because, although present uncertainties, when compared with punctual data measured in the field can provide good indicators of the spatial distribution of rainfall for a given area. In this research, we evaluate the potential of rainfall estimates from TRMM (Tropical Rainfall Measuring Mission) sensor to represent the spatio-temporal variability of precipitation in the State of Paraíba, in the Northeast of Brazil. In this study we considered daily time series of 14 years length of rainfall data collected by AESA (Agência Executiva de Gestão das Águas do Estado da Paraíba) in 269 rainfall gauges and rainfall data estimated from TRMM satellite for a spatial mesh of 198 grid points covering the Paraíba State and which have been interpolated to the rain gauge locations using the inverse squared distance method. Comparisons were made considering the accumulated rainfall in different periods of time: daily, three days, seven days and monthly. With respect to spatial factors, the comparisons were developed based on punctual values in rain gauges stations, areal averages over sub-basins and mesoregions, and topographic profile. The statistical analyzes of comparison between the observed and estimated rainfall were developed based on the average rainfall, the linear correlations, the mean absolute error and root mean square error considering each accumulated period. Regarding the daily precipitation, the majority of the rain gauges (91%) showed correlation coefficients ranging from 0.5 to 0.7. This correlation increases for considering 3 days-rainfall, with values ranging from 0.5 to 0.7 in 56% of rain gauges, and of 0.7-0.8 for 42% of rain gauges. For the 7 days-rainfall, 58% of the rain gauges presented correlations ranging from 0.7 to 0.8, while for the monthly rainfall 95% of the rain gauges obtained correlations higher than 0.8. Therefore, the results indicate that the TRMM satellite provides better estimates when data are accumulated in larger time intervals. The monthly analysis showed that March and April are the months with higher correlation between observed and estimated precipitation, and that in the first months of the year the estimated and observed values have better approximations for all types of analyzes. It was also verified a good estimation potential in the analysis of seasonal variability of precipitation. Moreover, it was observed that the satellite presents the largest errors in the areas with the largest amount of rainfall. In the sub-basins and in the mesoregions of the state the rainfall regime was estimated quite closely. We concluded that the TRMM satellite presents very good skill in reproducing the observed rainfall measured in the gauge stations over the Paraíba state, becoming an important data source for helping the water resources planning and decision making
A variabilidade temporal e espacial, que é um elemento característico da precipitação pluvial se configura como um fator de complexidade para as pesquisas sobre chuvas. Além disso, a baixa densidade de postos pluviométricos e os equívocos nos processos de coleta em campo aumentam as dificuldades na execução de estudos nessa área de pesquisa. No entanto, tais pesquisas são essenciais tendo em vista que é a partir delas que se pode fazer previsão de enchentes e estiagens, compreender o regime hidrológico dos rios, a umidade do solo, as mudanças de temperatura, dentre outras. Assim, as estimativas espaciais de precipitação realizadas por satélites são técnicas importantes, pois, embora contenham incertezas, quando comparadas com valores pontuais medidos em solo podem fornecer bons indicativos da distribuição espacial das chuvas para uma determinada área. Nesta pesquisa, avalia-se o potencial das estimativas de chuva do satélite TRMM, versão 7 e 3B42 (Tropical Rainfall Measuring Mission) para representar a variabilidade espaço-temporal da precipitação no Estado da Paraíba, no Nordeste do Brasil. No estudo considerou-se séries temporais de dados diários para um período de 14 anos (1998-2011) fornecidas pela AESA (Agência Executiva de Gestão das Águas do Estado da Paraíba) referentes a 269 postos pluviométricos e dados estimados pelo satélite TRMM numa malha espacial de 198 pontos que cobrem o Estado da Paraíba e que foram interpolados para os locais de observação de campo pelo método do inverso do quadrado da distância. As comparações foram realizadas considerando a chuva acumulada em diferentes períodos: diário, três dias, sete dias e mensal. Com relação aos fatores espaciais, os comparativos foram desenvolvidos com base em valores pontuais nos locais de observação, médias espaciais considerando sub-bacias, mesorregiões, e perfil topográfico. As análises estatísticas de comparação entre a chuva observada e a estimada foram desenvolvidas a partir das médias de chuva, das correlações lineares, do erro médio absoluto e da raiz do erro médio quadrático considerando cada período acumulado. Nas análises da chuva diária a maioria dos postos (91%) apresentou índices de correlação variando de 0,5 a 0,7. Esta correlação aumenta para os acumulados de 3 dias, com valores que variam de 0,5 a 0,7 em 56% dos postos pluviométricos e de 0,7 a 0,8 em 42% dos postos. Nos acumulados de 7 dias, 58% dos pluviômetros apresentaram correlações que variam de 0,7 a 0,8 e nos acumulados mensais 95% dos postos apresentam correlações superiores a 0,8. Portanto, os resultados indicam que o satélite TRMM apresenta melhores estimativas quando os dados estão acumulados em intervalos maiores de tempo. Na análise mensal verificou-se que março e abril são os meses mais significativos de estimação e que nos primeiros meses do ano os valores estimados e observados apresentam melhores aproximações para todos os tipos de análises. Identificou-se também bom potencial de estimação na análise da variabilidade sazonal de precipitação. Além disso, observou-se que o satélite apresenta os maiores erros para as áreas onde ocorrem os maiores volumes de chuva. Nas sub-bacias e nas mesorregiões do Estado, o regime de chuvas foi estimado com bastante fidelidade em todas as formas analisadas. Conclui-se que o satélite TRMM apresenta bom desempenho para reproduzir as chuvas observadas em pluviômetros no Estado da Paraíba, configurando-se como uma importante fonte de dados para o auxílio no planejamento e na tomada de decisões relativas aos recursos hídricos
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Tang, Yue-bun Alan. "Molecular and functional characterization of a testis-specific TRS4 gene in spermatogenesis." Click to view the E-thesis via HKUTO, 2010. http://sunzi.lib.hku.hk/hkuto/record/B43572169.
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Hermann, Scott A., Mark A. Wigent, and Tomas C. Chavez. "Pacific Ranges Interoperable Test & Evaluation Capabilities (PRITEC)." International Foundation for Telemetering, 2009. http://hdl.handle.net/10150/606152.
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ITC/USA 2009 Conference Proceedings / The Forty-Fifth Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2009 / Riviera Hotel & Convention Center, Las Vegas, NevadaThe office of the Defense Test Resources Management Center (DTRMC) has developed two major programs to achieve Joint/Interoperable exercises between DoD test and training ranges. Joint Mission Environment Test Capability (JMETC) defines a LVC environment in which Joint operations take place, while the Test and Training Enabling Architecture (TENA) defines the communication within that environment. Putting these programs to everyday use has been a challenge for the ranges. The Pacific Missile Range Facility (PMRF) is executing the Central Test & Evaluation Investment Program (CTEIP) sponsored Pacific Ranges Interoperable Test & Evaluation Capabilities (PRITEC) project designed to develop a set of tools that will facilitate implementation of JMETC and TENA. This paper will discuss the PRITEC project in detail.
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Raoof, Saad Mahmood. "Bond between textile reinforced mortar (TRM) and concrete substrate." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/44141/.
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There is a growing interest for strengthening and upgrading existing concrete structures both in seismic and non-seismic regions due to their continuous deterioration as a result of aging, degradation induced environment conditions, inadequate maintenance, and the need to meet the modern codes (i.e. Eurocodes). Almost a decade ago, an innovative cement-based composite material, the so-called textile-reinforced mortar (TRM), was introduced in the field of structural retrofitting. TRM comprises high-strength fibres in form of textiles embedded into inorganic matrices such as cement-based mortars. TRM offers well-established advantages such as: fire resistance, low cost, air permeability, and ability to apply on wet surfaces and at ambient of low temperatures. It is well known that the effectiveness of any external strengthening system in increasing the flexural capacity of concrete members depends primarily on the bond between the strengthening material and member’s substrate. This PhD Thesis provides a comprehensive experimental study on the bond behaviour between TRM and concrete substrate and also provides a fundamental understanding of the flexural behaviour of RC beams strengthened with TRM. Firstly, the tensile properties of the textile reinforcement were determined through carrying out tensile tests on bare textiles, and TRM coupons. Secondly, the bond behaviour between TRM and concrete substrates both at ambient and, for the first time, at high temperature was extensively investigated. A total of 148 specimens (80 specimens tested at ambient temperature and 68 specimens tested at high temperatures) were, fabricated, and tested under double-lap shear. Parameters investigated at ambient temperature comprised: (a) the bond length; (b) the number of layers; (c) the concrete surface preparation; (d) the concrete compressive strength; (e) the textile surface condition; and (f) the anchorage through wrapping with TRM jackets. Whereas, the parameters examined at high temperatures included: (a) the strengthening systems (TRM versus FRP); (b) the level of temperature at which the specimens were exposed; (c) the number of FRP/TRM layers; and (d) the loading conditions. The results of ambient temperature tests indicated that the bond at the TRM-concrete interface is sensitive to parameters such as: the number of layers, the textile surface condition, and the anchorage through wrapping with TRM. On the other hand, the results of high temperature tests showed that TRM exhibited excellent bond performance with concrete (up to 400 0C) contrary to FRP which practically lost its bond with concrete at temperatures above the glass trainset temperature (Tg). The flexural strengthening of RC beams with TRM at ambient and for the first time at high temperature was also examined carrying out 32 half-scale beams. The examined parameters were: (a) the strengthening system (TRM versus FRP); (b) the number of layers; (c) the textile surface condition; (d) the textile fibre material; (e) the end-anchorage system of the external reinforcement; and (f) the textile geometry. The results of ambient temperature tests showed that TRM was effective in increasing the flexural capacity of RC beams but its effectiveness was sensitive to the number of layers. Furthermore, a simple formula used for predicting the mean FRP debonding stress was modified for predicting the TRM debonding stress based on the experiment data available. The results of high temperature tests showed that TRM maintained an average effectiveness of 55%, of its effectiveness at ambient temperature, contrary to FRP which has totally lost its effectiveness when subjected to high temperature. Finally, a stress reduction factor of TRM flexural effectiveness (compared to its ambient effectiveness) when subjected to high temperature was also proposed.
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Bernardi, Ewerthon Cezar Schiavo. "QUALIDADE DAS ESTIMATIVAS DE PRECIPITAÇÃO DO SATÉLITE TRMM NO ESTADO DO RIO GRANDE DO SUL." Universidade Federal de Santa Maria, 2016. http://repositorio.ufsm.br/handle/1/7658.
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Fundação de Amparo a Pesquisa no Estado do Rio Grande do SulUnderstanding the spatial and temporal rainfall occurrence, improves the water resources management, both in order to prevent losses related to the occurrence of floods and droughts events, as in relation to the supply of the various sectors. Thus, satellite rainfall estimates are an alternative to obtain representative data of large areas, since the gauge data from meteorological stations are scarce, frequently due the low density of stations per area. However, these satellite products contain uncertainties when compared to gauge data. In this way, this study aims to evaluate the representativeness of rainfall estimates derived from satellites in the Rio Grande do Sul state. To this, were used satellite TRMM (3B42 V7) products, which were compared with gauge data in the State provided by the Agência Nacional de Águas and by the Instituto Nacional de Meteorologia, considering the period from 1998 to 2013. This paper compared rainfall estimates and gauge data was accomplished through a set statistics like skill scores, such as event detection percentage (PC), hit rate (H), false alerts ratios (FAR and F), critical success index (CSI), the ratio of planned events and observed (B), and the indexes of Heidke (HSS) and Pierce (PSS). Some equations were applied too: correlation coefficient (r) mean absolute error (MPE), root mean square error (RMSE), the Nash-Sutcliffe efficiency coefficient (NS) and bias. The data were compared in daily and accumulated series of 15 and 30 days, through the following methods: Pixel to Point, Point to Point, Pixel to Pixel, from Sub-pixels and aggregate analysis. The 3B42 products were also evaluated for their skill to determine heavy rainfall, using as reference intensity-duration-frequency equations (IDF) derived from gauge data. The results obtained by the methods, except for the analysis of heavy rainfall, not differ much from each other. Spatial analysis showed the relationship of assessments estimates has to the density of stations and the regions of Rio Grande do Sul, while specific analyzes indicated the good performance of TRMM even in Pixel to Point comparison. The results improved in steps that the daily series were accumulated in 15 and 30 days. It was evident the decrease of the quality of the estimates in the eastern RS region, where the ocean effects generates overestimates.
A compreensão da ocorrência espacial e temporal da precipitação pluviométrica permite melhorar a gestão dos recursos hídricos, tanto no sentido de prevenir prejuízos relacionados à ocorrência de eventos de enchentes e estiagens, quanto em relação ao suprimento dos diversos setores. Assim, estimativas de precipitação de satélites são uma alternativa para obtenção de dados representativos de extensas áreas, tendo em vista que os dados observados em estações meteorológicas são escassos muitas vezes. Todavia, estes produtos de satélite contêm incertezas quando comparados aos dados medidos. O estudo procura avaliar a representatividade das estimativas de chuva oriundas de satélites no estado do Rio Grande do Sul. Para tal utilizaramse produtos do satélite TRMM (3B42 V7), que foram comparados com observados no Estado, disponibilizados pela Agência Nacional de Águas e pelo Instituto Nacional de Meteorologia, no período de 1998 a 2013. O trabalho consistiu em comparar dados de precipitações estimadas e observadas por meio de um conjunto de índices de desempenho, tais como o percentual de detecção de eventos (PC), percentual de acertos (H), percentual de falsos alertas (FAR e F), índice de sucesso crítico (CSI), a razão entre eventos previstos e observados (B), bem como os índices de Heidke (HSS), e Peirce (PSS). Além de outras equações como: coeficiente de correlação (r) erro médio absoluto (EMA), erro médio quadrático (EQM), o coeficiente de eficiência de Nash-Sutcliffe (NS) e viés. Os dados foram comparados em séries diárias e acumulados de 15 e 30 dias, por meio dos seguintes métodos: Pixel a Ponto, Ponto a Ponto, Pixel a Pixel, a partir de Sub-pixels e Análise agregada. Os produtos 3B42 também foram avaliados em relação a capacidade de determinar chuvas intensas, usando como referência equações de intensidade-duração-frequência derivadas de dados observados. Os resultados obtidos pelas metodologias, com exceção da análise de precipitações intensas, não diferenciaram muito entre si. As análises espaciais mostraram a intimidade das avaliações das estimativas tem com a densidade de postos e com as regiões do Rio Grande do Sul, enquanto as análises pontuais indicaram a boa performance do TRMM mesmo na comparação Pixel a Ponto. A medida que as séries diárias foram acumuladas em 15 e 30 dias, os resultados melhoraram. Ficou evidente o decréscimo da qualidade das estimativas na região Leste do RS, onde os efeitos da maritimidade acabam gerando superestimativas.
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Paula, Stefany Correia de. "PRECIPITAÇÃO ESTIMADA POR SATÉLITE PARA USO EM MODELO CONCENTRADO CHUVA-VAZÃO APLICADO EM DIFERENTES ESCALAS DE BACIAS." Universidade Federal de Santa Maria, 2015. http://repositorio.ufsm.br/handle/1/7906.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorIn Hydrological rainfall-runoff models, rainfall is one of the main variables analyzed before being used as input data. However, its peculiar characteristics of occurrence make it challenging to measure, especially for developing countries, since it requires monitoring networks with high spatial and temporal resolutions. To overcome such problems, the use of remote sensing to estimate rainfall is being gradually diffused, with results considered of good reliability. In this sense, the objective was to evaluate the results generated by a rainfall-runoff modeling, using precipitation information estimated by the TRMM satellite, applied to four watersheds of different scales. To achieve this objective was used the concentrated model IPH II in the version for Windows® (WIN_IPH2 version 2, denominated in this work as WIPH2). In a first analysis, conducted for the watersheds of the rivers Turvo (1,540 km2), Ijuí (9,450 km2), Jacuí (38,700 km2) and Alto Uruguai (61,900 km2), which are located in southern Brazil, it was observed that the precipitation estimates provided by the TRMM satellite generated consistent spatialized mean rainfall in relation to the generated by rain gauges networks. Were found errors about 7.5% (Ijuí River watershed) to 15% (Turvo River, Jacuí River and Alto Uruguai watersheds). In overall, the daily mean rainfall, generated by the TRMM estimates, increased their correlation with the rain gauges information, as there was an increase in the watershed drainage area. In the modeling, it was noted that the WIPH2 showed good fit for the simulation of flows in the selected watersheds, with exception to the application in the Alto Uruguai watershed. In some cases, even though the mean rainfall estimated by the TRMM had generated greater uncertainty regarding the data generated by the different rain gauge networks, the model was able to compensate the deficiency of this information, by changing parameters within limits considered acceptable for the characteristics watershed. It was found that, in overall, precipitation estimated by the TRMM produced improvements in the flow evaluation coefficient (Nash-Sutcliffe NS, and correlation R coefficients), as there was an increase in the watershed drainage area until the Jacuí River watershed, with a decrease of the coefficients for the Alto Uruguai watershed, which was probably caused by the inadequacy of the WIPH2 concentrated model to the heterogeneous characteristics of the last watershed. In places with good rainfall monitoring coverage, the satellite estimates produced lower results than those generated by information measured by rain gauges. In places where the lack of equipment is accentuated and/or their distribution is non-uniform, the use of satellite estimates proved to be more reliable, reaching clearly superior results. In this sense, it was concluded that the TRMM satellite estimates may present as good alternatives to watersheds with scarce rainfall information measures on the ground, having great chances to show better results when compared to information of rain gauges scarce and poorly distributed.
Nos modelos hidrológicos chuva-vazão, a precipitação é uma das principais variáveis analisadas antes de ser utilizada como informação de entrada. Entretanto, suas características peculiares de ocorrência a tornam de mensuração desafiadora, principalmente para países em desenvolvimento, já que requer redes de monitoramento com elevadas resoluções espaciais e temporais. Para contornar tais problemas, o uso do sensoriamento remoto para estimar precipitações está sendo aos poucos difundido, com resultados considerados de boa confiabilidade. Neste sentido, objetivou-se avaliar os resultados gerados por uma modelagem chuva-vazão, utilizando-se de informações de precipitação estimadas pelo satélite TRMM, aplicada a quatro bacias hidrográficas de diferentes escalas. Para isso foi utilizado o modelo concentrado IPH II, na versão para Windows® (WIN_IPH2 versão 2, denominado neste trabalho como WIPH2). Em uma primeira análise, realizada para as bacias hidrográficas dos rios Turvo (1.540 km2), Ijuí (9.450 km2), Jacuí (38.700 km2) e Alto Uruguai (61.900 km2), localizadas na região sul do Brasil, observou-se que as estimativas de precipitação fornecidas pelo satélite TRMM geraram chuvas médias espacializadas consistentes em relação às geradas pelas redes de pluviômetros, apresentando erros de volume na ordem de 7,5% (bacia do Rio Ijuí) a 15% (bacias dos rios Turvo, Jacuí e Alto Uruguai). Em geral, as chuvas médias diárias, geradas pelas estimativas do TRMM, aumentaram suas correlações com as informações de pluviômetros, conforme houve um aumento da área de drenagem da bacia hidrográfica. Na modelagem, notou-se que o WIPH2 mostrou bom ajuste para a simulação das vazões nas bacias selecionadas, com ressalvas à aplicação na bacia do Alto Uruguai. Em alguns casos, mesmo que a precipitação média estimada pelo TRMM possuísse maior incerteza com relação aos dados gerados pelas diferentes redes de pluviômetros, o modelo conseguiu compensar a deficiência desta informação, por meio da alteração de parâmetros, dentro de limites considerados aceitáveis para as características das bacias hidrográficas. Verificou-se que, em geral, as precipitações estimadas pelo TRMM produziram melhoras no coeficiente de avaliação das vazões (coeficientes de Nash-Sutcliffe NS, e de correlação - R), à medida em que houve um aumento da área de drenagem da bacia hidrográfica até a bacia do Rio Jacuí, com decréscimo dos coeficientes para a bacia do Alto Uruguai, que provavelmente foi causado pela falta de adequação do modelo concentrado WIPH2 às características heterogêneas da última bacia. Em locais com boa cobertura de monitoramento pluviométrico, as estimativas de satélite produziram resultados inferiores aqueles gerados por informações mensuradas em solo; já em locais onde a escassez de equipamentos é acentuada e/ou sua distribuição é não-uniforme, a utilização de estimativas de satélite se mostrou mais confiável, chegando a resultados visivelmente superiores. Neste sentido, concluiu-se que as estimativas do satélite TRMM podem se apresentar como boas alternativas para bacias com escassez de informações de precipitação medidas em solo, tendo grandes chances de apresentarem melhores resultados quando comparadas com informações pontuais escassas e mal distribuídas.
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So, Kam-hei, and 蘇錦熙. "A study on the role of temperature repressed sequence 4 (Trs4) in spermatogenesis." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B47310704.
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Heat stress inhibits spermatogenesis partly by inducing apoptosis in the testicular germ cells. Using a cryptochid rat model, we identified a temperature-related ESTs 4 (TRS4) transcript from rat testis. Trs4 mRNA is specifically expressed in the mouse and rat testis from postnatal day 21 and 28 days onwards, respectively. Trs4 protein is located mainly in the elongating spermatids and mature spermatozoa at the acrosome and tail regions. Using a yeat-2-hybrid screening, Trs4 was found to bind Gstmu1, Rslh-2 and Ddc8 proteins. To further characterize the functional role of Trs4 in spermatogenesis, and study how Trs4 interacts its binding proteins for cellular functions, we aimed (1) to screen putative ES cells with Trs4 floxed allele for knockout mice generation, (2) to generate Trs4 deletion constructs and study the cellular localization of Trs4 and its putative binding partners in transfected spermatocyte GC-2spd(s) cell line, (3) to study how heat-treatment regulates the expression of Trs4 and apoptotic molecules. The Trs4 conditional targeting vector was constructed by flanking exons 4-6 with two LoxP sites and electroporated into ES cells. After screening of 480 clones, positive ES cell clones were identified by Southern blotting using 5’- and 3’- probes. Three putative positive clones were identified carrying the floxed allele. Trs4 protein contains putative ubiquitin-like motif (a.a. 119-224), IQ-calmodulin binding motif (a.a. 334-362) and a overlapping bipartite nuclear localization signal (BNL) (a.a. 346-362). Transfection of EGFP fused Trs4 truncated protein demonstrated that the IQ-calmodulin binding motif and BNL signal was important for localization of Trs4 protein in the cytoplasmic/Golgi regions; while the N-terminal contains ubiquitin-like motif and the C-terminal regions direct the expression of the EGFP-fusion protein mainly to the nucleus. The full-length sequence of Trs4 binding partners: Gstmu1, Rshl-2 and Ddc8 were cloned into the pDsRedmonomer-C1 vector, giving red fluorescence protein in the transfected cells. They were colocalized with EGFP-Trs4 in the cytoplasm of the cells, confirming that Trs4 and its interacting protein is likely interact with each other in vivo. As Trs4 colocalize with Gstmu1, a modulator of mitochondrial-dependent pathway in apoptosis, it is suggested that Trs4 is an upstream regulator of apoptosis under heat treatment in germ cells. The functional roles of Trs4 protein Trs4 and apoptotic molecules. The Trs4 conditional targeting vector was constructed by flanking exons 4-6 with two LoxP sites and electroporated into ES cells. After screening of 480 clones, positive ES cell clones were identified by Southern blotting using 5’- and 3’- probes. Three putative positive clones were identified carrying the floxed allele. Trs4 protein contains putative ubiquitin-like motif (a.a. 119-224), IQ-calmodulin binding motif (a.a. 334-362) and a overlapping bipartite nuclear localization signal (BNL) (a.a. 346-362). Transfection of EGFP fused Trs4 truncated protein demonstrated that the IQ-calmodulin binding motif and BNL signal was important for localization of Trs4 protein in the cytoplasmic/Golgi regions; while the N-terminal contains ubiquitin-like motif and the C-terminal regions direct the expression of the EGFP-fusion protein mainly to the nucleus. The full-length sequence of Trs4 binding partners: Gstmu1, Rshl-2 and Ddc8 were cloned into the pDsRedmonomer-C1 vector, giving red fluorescence protein in the transfected cells. They were colocalized with EGFP-Trs4 in the cytoplasm of the cells, confirming that Trs4 and its interacting protein is likely interact with each other in vivo. As Trs4 colocalize with Gstmu1, a modulator of mitochondrial-dependent pathway in apoptosis, it is suggested that Trs4 is an upstream regulator of apoptosis under heat treatment in germ cells. The functional roles of Trs4 proteinpublished_or_final_version
Obstetrics and Gynaecology
Master
Master of Philosophy
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Eckstein, Eugenia [Verfasser], and Frank [Akademischer Betreuer] Zufall. "Trpm4 and Trpm5 in the murine olfactory system / Eugenia Eckstein ; Betreuer: Frank Zufall." Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2019. http://d-nb.info/1203128940/34.
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Wu, Yu [Verfasser], and Peter [Akademischer Betreuer] Heisig. "Ion channel TRPM4 activity and cardiac conduction disease / Yu Wu. Betreuer: Peter Heisig." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2012. http://d-nb.info/1030365644/34.
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DeMoss, Jeremy. "Changes in Tropical Rainfall Measuring Mission (TRMM) retrievals due to the orbit boost estimated from rain gauge data." [College Station, Tex. : Texas A&M University, 2006. http://hdl.handle.net/1969.1/ETD-TAMU-1732.
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Collier, Jonathan Craig. "Tropical precipitation simulated by the NCAR Community Climate Model (CCM3): an evaluation based on TRMM satellite measurements." Texas A&M University, 2004. http://hdl.handle.net/1969.1/2715.
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This study evaluates the simulation of tropical precipitation by the Community Climate
Model, Version 3, developed at the National Center for Atmospheric Research. For
an evaluation of the annual cycle of precipitation, monthly-mean precipitation rates from
an ensemble of CCM3 simulations are compared to those computed from observations of
the TRMM satellite over a 44-month period. On regional and sub-regional scales, the comparison
fares well over much of the Eastern Hemisphere south of 10◦S and over South
America. However, model - satellite differences are large in portions of Central America
and the Caribbean, the southern tropical Atlantic, the northern Indian Ocean, and the
western equatorial and southern tropical Pacific. Since precipitation in the Tropics is the
primary source of latent energy to the general circulation, such large model - satellite differences
imply large differences in the amount of latent energy released. Differences are
seasonally-dependent north of 10◦N, where model wet biases occur in realistic wet seasons
or model-generated artificial wet seasons. South of 10◦N, the model wet biases exist
throughout the year or have no recognizable pattern.
For an evaluation of the diurnal cycle of precipitation, hourly-averaged precipitation
rates from the same ensemble of simulations and for the same 44-month period are compared
to observations from the Tropical Rainfall Measuring Mission (TRMM) satellite.
Comparisons are made for 15◦ longitude ?? 10◦ latitude boxes and for larger geographical
areas within the Tropics. The temporally- and spatially-averaged hourly precipitation rates
from CCM3 and from TRMM are fit to the diurnal harmonic by the method of linear leastsquares
regression, and the phases and the amplitudes of the diurnal cycles are compared.
The model??s diurnal cycle is too strong over major land masses, particularly over South
America (by a factor of 3), and is too weak over many oceans, particularly the northwestern
Tropical Pacific (by a factor of 2). The model-satellite phase differences tend to be
more homogeneous. The peak in the daily precipitation in the model consistently precedes
the observations nearly everywhere. Phase differences are large over Australia, Papua New
Guinea, and Saharan Africa, where CCM3 leads TRMM by 4 hours, 5 to 6 hours, and 9 to
11 hours respectively. A model sensitivity experiment shows that increasing the convective
adjustment time scale in the model??s deep convective parameterization reduces its positive
amplitude bias over land regions but has no effect on the phase of the diurnal cycle.
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El, Euch Sami. "Validation des pluies de surface estimées par le satellite TRMM et le radar au sol WSR-88D dans le Nord-Est du Mexique." Mémoire, Université de Sherbrooke, 2009. http://savoirs.usherbrooke.ca/handle/11143/2592.
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Les précipitations présentent un impact socio-économique très important notamment dans les régions où les ressources hydriques sont rares et où les évènements pluvieux ont un caractère torrentiel. Plusieurs modèles hydrologiques ont vu le jour dans le but de prédire les débits qui sont d'une grande utilité pour la conception des barrages ou pour la prévision des inondations. Or, pour fournir des simulations de débit très proches de la réalité, ces modèles ont besoin de données pluviométriques acquises à grande résolution spatio-temporelle. De ce fait, il est intéressant pour ces modèles hydrologiques de recourir aux pluies estimées par les radars météorologiques satellitaires et au sol. Néanmoins, ces données doivent être validées avant toute utilisation. Le principal problème rencontré dans la validation des données radar météorologiques réside dans la grande différence d'échelle spatio-temporelle entre les données radar et les données fournies par les stations pluviométriques. Cette différence d'échelle ne peut pas être prise en compte par les méthodes conventionnelles de validation qui se limitent à calculer le coefficient de corrélation et à élaborer une relation régulière entre les deux types de données. L'objectif général de ce travail de recherche est la validation des pluies de surface estimées aussi bien par le radar satellitaire de TRMM que par le radar au sol NEXRAD WSR-88D afin d'améliorer l'échelle spatiale des simulations hydrologiques. Les données au sol utilisées pour la validation sont celles issues des stations pluviométriques du CNA ( Comisión Nacional del Agua ) et de la NOAA (National Oceanic and Atmospheric Administration ) localisées dans la région de Rio Escondido au Nord-Est du Mexique. Cette validation est réalisée en calculant les coefficients de corrélation entre les données de précipitation radar et les données au sol, en vérifiant l'existence de la propriété d'invariance d'échelle, et en évaluant la fiabilité des sorties du modèle hydrologique CEQUEAU utilisant les données radar comme entrée. La contribution principale de ce travail est d'utiliser la dimension fractale du champ de pluie comme outil de validation des estimations pluviométriques. Les résultats ont confirmé que les précipitations de surface estimées par le radar du satellite TRMM ne présentent pas les mêmes caractéristiques spatiales que celles des mesures fournies par les pluviomètres. Contrairement aux précipitations estimées par TRMM, les données du radar au sol sont compatibles avec un comportement d'échelle fractal et traduisent la variabilité intrinsèque du champ de pluie. C'est pourquoi elles ont été utilisées comme données d'entrée dans le modèle hydrologique CEQUEAU. Il en résulte des débits simulés avec un coefficient de Nash variant de -2,59 à 0,97. L'intérêt de ce résultat est qu'il montre l'utilité des données radar au sol pour les simulations des modèles hydrologiques et ce, particulièrement dans les zones où les pluies sont convectives, donc fortement variables et où les réseaux de pluviographes peuvent être insuffisants ou mal répartis. Cependant, la qualité de la simulation hydrologique dépend de l'échelle temporelle considérée et de l'évènement pluvieux choisi. Ainsi, ce travail a permis d'appliquer plusieurs méthodes de validation aux estimations radar des pluies de surface et de démontrer la pertinence de considérer les différences d'échelles spatio-temporelles dans la validation de ces données estimées.
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Tsutsui, Yusuke. "Development of Contactless Conductivity Measurement System with Microwave Probe and Its Applications for Organic Semiconductors." Kyoto University, 2019. http://hdl.handle.net/2433/242530.
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Tetta, Zoi. "Shear strengthening of concrete members with Textile Reinforced Mortar (TRM)." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/43314/.
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The issue of upgrading existing structures is of great importance due to their deterioration (ageing, environmental induced degradation, lack of maintenance, need to meet the current design requirements). Recently, an innovative structural material, the so-called Textile-Reinforced Mortar (TRM), was successfully developed for structural retrofitting of deficient masonry and concrete structures. TRM is an advanced sustainable material which offers well-established advantages (good behaviour at high temperature, compatibility to concrete or masonry substrates material high strength to weight ratio, corrosion resistance, ease and speed of application, minimal change of cross section dimensions) at a low-cost and over the last decade it has been reported in the literature that TRM is a very promising alternative to the FRP (Fibre Reinforced Polymers) retrofitting solution. This study evaluates the use of TRM jacketing for shear strengthening of Reinforced Concrete (RC) beams. First of all, the materials used for strengthening are described and the tensile and shear behaviour of textiles was characterised through tensile and picture-frame tests, repsectively. Moreover, the tensile properties of TRM composite material are experimentally obtained through bell-shaped TRM coupons. Shear strengthening of RC beams was extensively studied carrying out 55 medium-scale rectangular beams and 14 full-scale T-beam ends. The key investigated parameters on medium-scale rectangular beams comprise: (a) the strengthening system (TRM versus FRP), the (b) strengthening configuration, (c) the number of layers, (d) the external reinforcement ratio, (e) the textile material mesh characteristics, (f) the shear-span-to depth ratio and (g) the optimisation of the textile geometry. It was concluded that TRM was very effective on increasing the shear resistance of RC beams but its effectiveness was sensitive to parameters such as the strengthening configuration, the number of layers and the textile characteristics. Experimental work was also conducted on full-scale T-beams focused on the use of a novel end-anchorage system comprising textile-based anchors to delay or prevent the debonding of TRM jacket. In particular, the anchorage percentage of the U-jacket, the number of layers, the textile material, the textile geometry and the strengthening system (TRM versus FRP jackets) were the main investigated parameters. U-shaped TRM jackets significantly increased the shear capacity of full-scale T-beams, whereas the use of textile-based anchors improved dramatically the effectiveness of the TRM jackets. A simple design model was also proposed to calculate the contribution of anchored TRM jackets to the shear capacity of RC T-beams. The behaviour of TRM at high temperature used for shear strengthening of both medium-scale and full-scale beams was studied for the first time through demanding tests in which loading and high temperature were simultaneously applied. Based on the experimental results, TRM jacketing remained very effective at high temperature, whereas the effectiveness of side-bonding and U-wrapping FRP jacketing was reduced nearly to zero when subjected at temperatures above the glass transition temperature (Tg). A stress reduction factor for TRM and FRP systems was also introduced to take into account the decrease in the effectiveness of both TRM and FRP jacket due to explosion of specimens to high temperature. Finally, design models for the prediction of the contribution of the TRM jacket to the total shear resistance were proposed for each failure mode and verified with the available experimental data.
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Zagrodnik, Joseph P. "Comparison and Validation of Tropical Rainfall Measuring Mission (TRMM) Rainfall Algorithms in Tropical Cyclones." FIU Digital Commons, 2012. http://digitalcommons.fiu.edu/etd/903.
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Tropical Rainfall Measuring Mission (TRMM) rainfall retrieval algorithms are evaluated in tropical cyclones (TCs). Differences between the Precipitation Radar (PR) and TRMM Microwave Imager (TMI) retrievals are found to be related to the storm region (inner core vs. rainbands) and the convective nature of the precipitation as measured by radar reflectivity and ice scattering signature. In landfalling TCs, the algorithms perform differently depending on whether the rainfall is located over ocean, land, or coastal surfaces. Various statistical techniques are applied to quantify these differences and identify the discrepancies in rainfall detection and intensity. Ground validation is accomplished by comparing the landfalling storms over the Southeast US to the NEXRAD Multisensor Precipitation Estimates (MPE) Stage-IV product. Numerous recommendations are given to algorithm users and developers for applying and interpreting these algorithms in areas of heavy and widespread tropical rainfall such as tropical cyclones.
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Hof, Thomas. "Implication du canal cationique non-sélectif TRPM4 dans l’activité électrique du tissu conducteur cardiaque." Caen, 2015. http://www.theses.fr/2015CAEN2022.
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Li, Yao. "Contributions of TRPM4 and Rho Kinase to Myogenic Tone Development in Cerebral Parenchymal Arterioles." ScholarWorks @ UVM, 2016. http://scholarworks.uvm.edu/graddis/464.
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Cerebral parenchymal arterioles (PAs) play a critical role in assuring appropriate blood flow and perfusion pressure within the brain. PAs are unique in contrast to upstream pial arteries, as defined by their critical roles in neurovascular coupling, distinct sensitivities to vasoconstrictors, and enhanced myogenic responsiveness. Dysfunction of these blood vessels is implicated in numerous cardiovascular diseases. However, treatments are limited due to incomplete understanding of the fundamental control mechanisms at this level of the circulation. One of the key elements within most vascular networks, including the cerebral circulation, is the presence of myogenic tone, an intrinsic process whereby resistance arteries constrict and reduce their diameter in response to elevated arterial pressure. This process is centrally involved in the ability of the brain to maintain nearly constant blood flow over a broad range of systemic blood pressures. The overall goal of this dissertation was to investigate the unique mechanisms of myogenic tone regulation in the cerebral microcirculation. To reveal the contributions of various signaling factors in this process, measurements of diameter, intracellular Ca2+ concentration ([Ca2+]i), membrane potential and ion channel activity were performed. Initial work determined that two purinergic G protein-coupled receptors, P2Y4 and P2Y6 receptors, play a unique role in mediating pressure-induced vasoconstriction of PAs in a ligand-independent manner. Moreover, a particular transient receptor potential (TRP) channel in the melastatin subfamily, i.e. TRPM4, was also identified as a mediator of PA myogenic responses. Notably, the observations that inhibiting TRPM4 channels substantially reduces P2Y receptor-mediated depolarization and vasoconstriction, and that P2Y receptor ligands markedly activate TRPM4 currents provide definitive evidence that this ion channel functions as an important link between mechano-sensitive P2Y receptor activation and the myogenic response in PAs. Next, the signaling cascades that mediate stretch-induced TRPM4 activation in PA myocytes were explored. Interestingly, these experiments determined that the RhoA/Rho kinase signaling pathway is involved in this mechanism by facilitating pressure-induced, P2Y receptor-mediated stimulation of TRPM4 channels, leading to subsequent smooth muscle depolarization, [Ca2+]i increase and contraction. Since Rho kinase is generally accepted as a 'Ca2+-sensitization' mediator, the present, contrasting observations point to an underappreciated role of RhoA/Rho kinase signaling in the excitation-contraction mechanisms within the cerebral microcirculation. Overall, this dissertation provides evidence that myogenic regulation of cerebral PAs is mediated by mechano-sensitive P2Y receptors, which initiate the RhoA/Rho kinase signaling pathway, subsequent TRPM4 channel opening, and concomitant depolarization and contraction of arteriolar smooth muscle cells. Revealing the unique mechanochemical coupling mechanisms in the cerebral microcirculation may lead to development of innovative therapeutic strategies for prevention and treatment of microvascular pathologies in the brain.
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El, Houfi Younas. "PKCα interagit avec la sous-unité catalytique de la m1A58 ARNt méthyltransférase Trm6-Trm61." Thesis, Montpellier 1, 2011. http://www.theses.fr/2011MON1T008/document.
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La protéine kinase C alpha (PKCα) est une sérine/thréonine kinase ubiquitaire. Elle intervient dans la régulation de différentes fonctions cellulaires en interagissant avec de nombreuses protéines. Parmi ces dernières, nous avons réussi à identifier Trm61, la sous-unité catalytique de la m1A58 ARNt méthyltransférase qui joue un rôle essentiel dans la stabilité de l'ARNtiMet. Les études de localisation de PKCα et des deux sous-unités Trm6 et Trm61 ont permis de démonter que ces deux sous-unités ne partagent pas toujours les mêmes compartiments cellulaires : si la sous-unité Trm6 est toujours nucléaire, la Trm61 est pancellulaire et se co-localise avec PKCα dans le cytoplasme. Nous avons apporté la preuve que l'augmentation de l'expression de PKCα entraîne une diminution de Trm61, alors que la diminution de l'expression de PKCα s'accompagne d'une augmentation aussi bien de Trm61 que d'ARNtiMet et se traduit par une importante augmentation de la prolifération à forte densité cellulaire. Ce travail a permis également de démontrer que la sous-unité Trm61 est essentielle pour la survie des cellules C6. La surexpression de Trm6 et/ou de Trm61 a permis de pointer la Trm6 comme le déterminant essentiel du niveau de la m1A58 ARNt méthyltransférase fonctionnelle et de suggérer un rôle secondaire de Trm61 cytoplasmique dans la régulation de la prolifération de façon indépendante de l'action du complexe Trm6-Trm61. De façon intéressante, les gliomes de bas grade présentent des taux plus élevés d'ARNm PKCα que les glioblastomes et inversement pour les taux des ARNm TRM6 et TRM61, apportant un argument en faveur de la relevance de nos observations dans la tumorigenèse gliale humaineProtein kinase C alpha (PKCα) is a ubiquitous serine/threonine kinase. It is involved in the regulation of various cellular functions by interacting with many intracellular proteins. Among these, we were able to identify Trm61, the catalytic subunit of the tRNA m1A58 methyltransferase which plays an essential role in the stability of the tRNAiMet. Localization studies of PKCα, Trm6 and Trm61 demonstrated that these two subunits do not always share the same subcellular compartment: while Trm6 is strictly nuclear, Trm61 is both in the nucleus and in the cytoplasm where it co-localizes with PKCα. We also provided the evidence that the increased expression of PKCα induces a decrease in that of Trm61, while reduced PKCα expression is accompanied by an increase in both Trm61 and tRNAiMet levels. These changes in expression are accompanied by a significant increase in cell proliferation at high-density. This work has also shown that Trm61 subunit is essential for the survival of the C6 glioma cell line. Our results suggest that Trm6 is the essential determinant of functional tRNA m1A58 methyltransferase level and we discuss the possibility of a secondary role for cytoplasmic Trm61 in the regulation of the proliferation independently of Trm6-Trm61 action. Interestingly, human grade II and III gliomas expressed higher levels of PKCα mRNA than glioblastomas and inversely for TRM6 and TRM61 mRNA levels, arguing for a relevance of our observations for human gliomagenesis
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Létoquart, Juliette. "Etudes structurales et fonctionnelles de complexes entre Trm112 et différentes méthyltransférases impliquées dans la traduction." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA114821/document.
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La traduction représente un processus central au sein de la cellule, elle assure le transfert de l’information génétique de l’ARNm vers les protéines. De nombreux acteurs y sont impliqués directement ou indirectement et parmi eux, chez les eucaryotes, la petite protéine Trm112. Celle-ci participe à la modification de plusieurs acteurs directs en interagissant et en activant quatre MTases. Le facteur de terminaison eRF1 est méthylé par le complexe Mtq2-Trm112, l’ARNr 18S par Bud23-Trm112 et certains ARNt par les complexes Trm9-Trm112 et Trm11-Trm112. Au cours de ce travail, les structures cristallographiques de Trm9-Trm112 et de Bud23-Trm112 de levure ont été résolues. L’étude comparative structurale de ces complexes et de la structure connue de Mtq2-Trm112, a permis de mettre en évidence que dans un même organisme, les séquences des trois protéines ont évolué de manière à conserver l’interaction avec Trm112. Même si les quatre partenaires présentent moins de 20% d’identité de séquence, les résidus clés pour l’interaction avec la petite protéine activatrice sont conservés ou partagent des caractéristiques identiques. En plus de l’analyse structurale, le complexe Trm9-Trm112 a fait l’objet d’une étude fonctionnelle chez S. cerevisiae ce qui a permis de cartographier le site actif de l’enzyme et de proposer un modèle de mécanisme d’action. Enfin, les premières études in vivo réalisées chez Haloferax volcanii suggèrent que cette plateforme serait également présente chez certains organismes procaryotesProtein synthesis is a central process in the cell; it ensures the transfer of genetic information from mRNA in to protein. A lot of actors are involved directly or indirectly in translation. In Eukaryotes, Trm112, a small protein, interacts with and activates four methyltransferases modifying direct actors of translation. The termination factor eRF1 is methylated by the Mtq2-Trm112 complex, the 18S rRNA by Bud23-Trm112 and some tRNA by the Trm9-Trm112 and Trm11-Trm112 complexes. During this work, the crystal structures of Trm9-Trm112 and Bud23-Trm112 complexes from yeast were solved. The comparative analysis of these two new structures with Mtq2-Trm112 structure highlights the structural plasticity allowing Trm112 to interact through a very similar mode with its partners although those share less than 20% sequence identity. In the same organism, the key residues for the interaction with Trm112 are conserved or share similar characteristics. In addition to the structural analysis, the function of the Trm9-Trm112 complex was studied in S. cerevisiae. This analysis allowed to map the active site of the enzyme and to propose a model of its mechanism of action. Finally, the first data obtained in vivo, with the Archaea Haloferax volcanii suggest that the Trm112 platform might also be present in some prokaryotic organisms
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Macedo, Luana Ribeiro. "O impacto do uso da técnica de assimilação de dados 3DVAR nos prognósticos do modelo WRF." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/111855.
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O uso da técnica de assimilação de dados meteorológicos é extremamente importante para a correção de imprecisões nos dados que compõem as condições iniciais e de fronteira dos modelos de previsão do tempo. Neste trabalho, faz-se uso da técnica de assimilação de dados 3DVAR contida no modelo de mesoescala WRF (Weather Research and Forecasting), o objetivo principal do trabalho é analisar o impacto da assimilação de dados meteorológicos de diversas fontes de dados (GTS – Sistema Global de Telecomunicações, estações automáticas, dados radar) no modelo WRF. Para analisar a consistência da assimilação de dados no WRF verificou-se a diferença entre a análise com e sem assimilação de dados. Confirmando a consistência da mesma, foram realizados os procedimentos necessários para gerar os prognósticos com assimilação de dados para cada caso individualmente. Os experimentos com assimilação de dados foram realizados para cada tipo de dado e em conjunto, possibilitando assim fazer uma análise do impacto que cada dado tem na previsão. Os resultados foram comparados entre si espacialmente utilizando dados do modelo global GFS (Global Forecast System) e satélite da Missão de Medida da Chuva Tropical (TRMM). A variável da precipitação acumulada foi comparada e validada espacialmente com os dados do TRMM, constatou-se para o caso do mês de janeiro uma superestimação dos valores acumulados para algumas regiões e para o caso do mês de abril uma subestimação, isso se deve ao fato da frequência temporal dos dados do satélite TRMM, pois provavelmente elas não foram compatíveis com o horário das precipitações. Quando comparado com o volume de chuva pontual com os dados da estação automática a maioria dos processamentos mostrou-se eficaz. Também no estudo de caso ocorrido no mês de janeiro a inserção de dados assimilados possibilitou uma melhora na intensidade e localização da célula convectiva. As variáveis da temperatura e do vento foram comparadas espacialmente com as análises do modelo GFS. A variável da temperatura ora apresentou valores superiores, ora inferiores ao modelo GFS, mesmo assim os resultados foram satisfatórios, uma vez que, foi possível simular temperaturas superiores antes da passagem do sistema e inferiores após a passagem do mesmo. Para o campo de vento houve uma pequena discrepância em todas as simulações em relação a magnitude, porém a direção do vento foi plotada de forma coerente, simulando até o ciclone presente no caso do mês de abril. Para o perfil vertical da temperatura e temperatura do ponto de orvalho o impacto da assimilação de dados foi pequeno, porém ambas as simulações representaram de forma coesa os perfis quando comparados com o perfil observado. Em suma, o estudo comprova que, embora se tenha algumas incoerências assimilação 3DVAR contribui de modo significativo nas previsões do tempo do modelo WRF.The use of meteorological data assimilation technique is extremely important for the correction of the imprecisions of observational data for the initial and boundary conditions of weather forecasting models. In the present work it is used the 3DVAR data assimilation technique of the mesoscale model WRF system (Weather Research and Forecasting) aiming the analysis of the impact of the assimilation of meteorological data from several data sources (GTS - Global Telecommunication System, automatic surface stations network and radar) in the WRF model. To analysis the consistency of the data in the WRF assimilation it has been gathered the difference between analysis, with and without data assimilation. Confirming its consistency the procedures required, to generate predictions with data assimilation for each individual case were performed. The data assimilation experiments were performed for each data type as well as including all of them allowing, therefore, the analysis of the impact of each over the forecast. The results were compared and validated using data from the spatially global forecasting model GFS (Global Forecast System), satellite and the mission of the Tropical Rain Measurement (TRMM) data. The cumulative rainfall variable was compared spatially with data from TRMM, where it has been observed, in the case of January, an overestimation of the accumulated values for some regions and an underestimation for the case of April. These have been occurred because of temporal frequency of the TRMM satellite data - which probably because were not compatible with the precipitation time occurrence. Comparison between the accumulated precipitation with data from automatic station presented mostly effective results. Also, in the case study of the January with assimilated data, produced an improvement in the intensity as well as in the location of the convective cell. The wind and temperature variables were compared with the spatially GFS’s analysis. The higher temperature variable values presented alternated, from higher and lower values compared to the GFS results. The results were nevertheless unsatisfactory, because the simulated temperatures presented prior to passing the frontal system and after passing it. For the wind field there was a small discrepancy in all simulations regarding the magnitude, but the wind direction was plotted consistently simulating up to the present in the case of April cyclone. For the vertical profiles of temperature and dew point temperature the impact of data assimilation was small, but both simulations made represented good profiles, compared with the observed values. In summary, the study shows that, although there were some inconsistencies, compared with the observations, the 3DVAR assimilation contributes significantly to WRF model forecasts.
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Casey, Sean Patrick. "The frequency of tropical precipitating clouds as observed by the TRMM PR and ICESat/GLAS." Thesis, [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-1895.
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Yeung, Seen-yu Aurora, and 楊善如. "Regulation and functional studies of the testis-specific temperature-related sequence 4 (TRS4) in spermatogenesis." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/208024.
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Temperature-related sequence 4 (Trs4) is a transcript identified from the testis of a cryptorchid rat model. TRS4 is firstly detected in round spermatids on postnatal day 21 mice, and is localized on the acrosome and tails of elongating spermatids and mature spermatozoa, suggesting a role in spermatogenesis. The present study aimed to investigate the regulatory and functional roles of Trs4 in spermatogenesis.
To investigate the hormonal regulation of Trs4 in vitro, mouse germ cell were co-cultured with Sertoli (TM4) cell-line for 24 hours with 1μM or 10nM testosterone and the expression of Trs4 was quantitated. It was found that testosterone treatment at physiological level (10nM) significantly down-regulated Trs4 mRNA expression. However, TRS4 protein level did not change significantly.
To investigate the functional roles of Trs4 and its interacting proteins (Rshl2, Gstmu1 and Ddc8) in spermatogenesis, the scrotal heat-treated rat model was used. The expression of Trs4, Rshl2, Gstmu1 and Ddc8 transcript were investigated on day 1, 9, 25, 37, 46, 56 and 79 post-heat treatment. Trs4, Rshl2 and Ddc8 transcripts were down-regulated on day 9 after heat-treatment, and recovered from day 37 onward. Immunohistochemical staining of TRS4 and RSHL-2 proteins showed they specifically localized in the cytoplasm of elongating spermatids in rat seminiferous tubules, suggesting that they might interact in regulating the development of elongating spermatids. Ten sessions of electroacupuncture (EA) was applied to the rats on day 9-36 to study the effect of EA in spermatogenesis. It was found that EA did not have any effect on the expression of Trs4, Rshl-2 and Ddc8 during recovery from hyperthermia when compared to the heat-treated only group. However, qPCR analysis on Gstmu1 mRNA expression showed a significant decrease in expression on day 46, and consistent with our TUNEL assay indicating a decrease in apoptosis in the EA group. Therefore, it is possible that Trs4 interacts with Gstmu1 and acts as anti-apoptotic factor for cell survival.
To understand functional roles of Trs4 in mouse spermatogenesis, five Trs4 chimeric mice were generated in our laboratory and germline transmissible 〖Trs4〗^(flox/+) mice were identified. Sycp1-Cre mice were used to breed with Trs4 floxed mice to generate Trs4 floxed mice expressing Cre recombinase in spermatocytes (〖Trs4〗^(flox/+);〖Sycp-Cre〗^(+/0)) and aiming to generate Trs4 heterozygous KO mouse. However, after screening 74 offspring, no Trs4 heterozygous KO mouse was identified in this study and was likely to be caused by the low efficiency of recombination in Sycp1-Cre mice. Then, Zp3-Cre mice that expressing Cre-recombinase in oocyte were employed. Crossing of 〖Trs4〗^(flox/+):Zp3-〖Cre〗^(+/0) mice and Trs4 floxed mice could not produce heterozygous or homozygous Trs4 KO mouse, but suggested an aberrant recombination process happened in vivo. PCR assay confirmed DNA rearrangement occurred in regions flanking the exon 4 to the second LoxP site in Trs4 floxed mice. Furthermore, the absence of 〖Trs4〗^(flox/flox) homozygous transgene suggested a possibility of insertional mutagenesis in the transgene. Future study is needed to confirm and characterize the insertion site of the floxed allele in order to generate Trs4 knockout mice for fertility study.published_or_final_version
Obstetrics and Gynaecology
Master
Master of Philosophy
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ANJOS, Rafael Silva dos. "Qualidade de dados do satélite TRMM para espacialização das chuvas na microrregião de Itaparica-PE." Universidade Federal de Pernambuco, 2017. https://repositorio.ufpe.br/handle/123456789/24919.
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A proposta dessa dissertação foi avaliar as estimativas do satélite TRMM na microrregião de Itaparica, localizada no semiárido pernambucano, mostrando-a como alternativa para complementação de dados de precipitação. A presente pesquisa está dividida em três etapas principais: averiguação das diferenças entre as estimativas e os dados observados em toda Microrregião de Itaparica, análise do comportamento das taxas de chuvas convectivas e estratiformes e sua relação com a qualidade das estimativas em Belém de São Francisco, e o estudo da distribuição espacial das chuvas, utilizando o Precipitation Radar. Para isso foram utilizados dados dos postos pluviométricos, taxas dos tipos de chuvas estratiformes e convectivas (Algoritmo 3A25), estimativas mensais de precipitação (Algoritmo 3B43) além do mapeamento da precipitação em três dimensões (2A25) para posteriormente fazer o processo de interpolação dos dados e análise estatística. Foi identificado que as diferenças entre as estimativas e os dados possuem variações espaço-temporais de acordo com algumas variáveis: quantidade precipitada, localização geográfica, série histórica. Além disso foi verificado que as taxas de chuvas convectivas e estratiformes apresentam maiores índices durante a estação chuvosa, podendo estar relacionadas com os erros mensais das estimativas totais de precipitação. Com a análise das estimativas do Precipitation Radar foi possível fazer uma análise prévia da distribuição horizontal e vertical das nuvens e sua relação com fatores climáticos.
The propose of this dissertation it was to evaluate the estimates of the TRMM satellite in Itaparica Microregion, localized at semiarid of Pernambuco, and to show how the estimates could be used for complementation of observed dates. The present research is divided in three principal steps: recognition of the differences between the estimates and observed dates, analyze of the behavior of rates of convective and stratiform rains and their relation with the quality of the estimates in Belém de São Francisco, and the application of Precipitation Radar to analyze of rains spatial distribution. For this, it was utilized dates of rain gauges, rates of stratiform and convective rain (Algorithm 3A25), monthly precipitation estimates (Algorithm 3B43), including the mapping 3D rain (2A25). With this dates, it was made the interpolations and statistics analyses. It was identified that the differences between the estimates and the observed dates have space-temporal variations, according with some factors: precipitation quantity, geographic localization, historic series. Besides, it was verified that the convective and stratiform rates had the biggest indices during the rainy season, it may be connected with the monthly errors of the precipitation estimates. Through analyzes of Precipitation Radar estimates, it was possible to make an previous observation of vertical e horizontal distribution of the clouds and your relations with climatic factors.
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Viana, Denilson Ribeiro. "Comportamento espaço-temporal da precipitação na Região Sul do Brasil utilizando dados TRMM e SRTM." Instituto Nacional de Pesquisas Espaciais (INPE), 2009. http://urlib.net/sid.inpe.br/mtc-m18@80/2009/05.07.19.05.
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Este trabalho investiga o comportamento espaço-temporal da precipitação pluvial na Região Sul do Brasil entre 1988 e 2007. A avaliação concentrou-se em três aspectos: 1) principais características climatológicas, 2) tendência geográfica, com base nas feições do relevo, e 3) principais modos de variabilidade. Foram utilizados dois conjuntos complementares de dados de precipitação: postos pluviométricos e estimativas de precipitação do satélite Tropical Rainfall Measuring Mission (TRMM), produto 3B43. A avaliação das feições do relevo foi conduzida com o auxílio do Modelo Digital de Elevação (MDE) oriundo do Shuttle Radar Topography Mission (SRTM), a partir do qual foram identificadas três sub-regiões: 1) Litoral, 2) Campanha e 3) Planalto. As características climatológicas da precipitação foram avaliadas através de estatísticas descritivas (média e desvio padrão) sazonal e anual. A análise de tendência geográfica foi realizada para cada sub-região identificada através de regressão linear múltipla da precipitação em relação às suas coordenadas (latitude e longitude). A variabilidade da precipitação foi avaliada por meio de Funções Ortogonais Empíricas (EOF), enquanto os sistemas atmosféricos responsáveis pelos principais modos de EOF foram investigados a partir dos boletins Climanálise. Os resultados da climatologia, quando comparados a estudos anteriores, apontam uma diminuição da participação da precipitação de inverno na região, e um aumento nas estações de transição, especialmente na primavera. Os desvios em relação à média variaram entre 40% e 70%. A tendência geográfica da precipitação foi mais expressiva na metade quente do ano no Litoral, em função da Zona de Convergência do Atlântico Sul (ZCAS) e de precipitações orográficas. Nos meses frios, a tendência foi mais pronunciada na Campanha devido aos sistemas frontais e ciclones extratropicais. No Planalto, a tendência mostrou-se moderada no verão devido a ZCAS; e no outono, por conta da atuação dos sistemas frontais e ciclones extratropicais. Os principais modos de variabilidade da precipitação têm como causas distintos sistemas. No inverno, destaca-se a atuação de sistemas frontais semi-estacionários, favorecidos por episódios de bloqueios atmosféricos. No inverno e estações de transição, destaca-se a atuação dos ciclones extratropicais, em geral em associação com sistemas frontais. Nos meses quentes, os Complexos Convectivos de Mesoescala são os principais responsáveis pela variabilidade observada.This work investigates the space-temporal behavior of rainfall in Southern Brazil during the 1988 and 2007 period. The evaluation was based on three features: 1) climatological aspects, 2) geographic trends from relief features, and 3) main variability modes. Two complementary data sets of rainfall were used: rain gauges and rainfall estimates from the Tropical Rainfall Measuring Mission (TRMM), product 3B43. The assessment of relief features was made using the Digital Elevation Model (MDE) from Shuttle Radar Topography Mission (SRTM), where three sub regions were identified: 1) Litoral (seacoast), 2) Campanha (countryside), and 3) Planalto (plateau). The rainfall climatological features were evaluated using basic statistics parameters. The trend geographic analysis was made for each sub region identified by multiple linear regression of rainfall versus their coordinates (latitude and longitude). The rainfall variability was evaluated by Empirical Orthogonal Functions (EOF), while the weather systems analysis associated with the EOF modes were based on Climanálise, from INPE/CPTEC. The climatological analysis show that rainfall amount is decreasing during the southern winter period, but it is increasing in the transition seasons, mainly in the southern spring. The standard deviations from the average were between 40% and 70%. The rainfall trend was most expressive in the warmest half of the year in Litoral sub region, because of South Atlantic Convergence Zone (ZCAS) and orographic precipitation. In the coldest months, the trend was more pronounced in Campanha due to frontal systems and extratropical cyclones. In the Planalto sub region, the trend was moderate in the summer due to ZCAS location, and in the autumn due to frontal systems and extratropical cyclones. The main modes of the observed rainfall variability in Southern Brazil have different causes. In the winter, the action of semi-stationary frontal systems was favored by blocking episodes. Also in the winter and transitions seasons, extratropical cyclones in association with frontal systems play an important role to the observed rainfall amount. In the warmest months, Mesoscale Convective Complexes was mainly responsible for the observed variability in the period.
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Fan, Tai-Fang. "Net Surface Flux Budget Over Tropical Oceans Estimated from the Tropical Rainfall Measuring Mission (TRMM)." W&M ScholarWorks, 2003. https://scholarworks.wm.edu/etd/1539626825.
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Fensterseifer, Cesar Augusto Jarutais. "QUALIDADE DAS ESTIMATIVAS DE PRECIPITAÇÕES DERIVADAS DE SATÉLITES NA BACIA DO ALTO JACUÍ-RS." Universidade Federal de Santa Maria, 2013. http://repositorio.ufsm.br/handle/1/7820.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorThe continuous increase in using satellite precipitation estimates as alternative sources for data have been increasing with the new technology of the devices. Therefore, the need for evaluating the quality and accuracy of these estimates is bigger. In this work, we assessed the TRMM satellite precipitation products 3B42 V6, 3B42 V7, and 3B42 Real Time, and the estimates from CMORPH method (RAW) by using the observed data from Alto do Jacuí basin region. To assess these products, we have used IPWG statistics to validate the estimate products such as PC (percent correct), H (hits), FAR (false alarm ratio) performance indexes, among others. We have also assessed products performance in detecting the occurrence and non-occurrence of different rainfall events. We have employed quantitative statistics to assess mean error (ME), root-mean-square error (RMSE), correlation coefficient (r), total errors and Nash-Sutcliffe (NS) efficiency coefficient (NSE). From the results, we have tried a methodology to improve them. The PC indexes showed an average of 81.3%, and they had a similar behavior among the products, while the H index showed an average of 60%. These numbers stress that the main difficulty is to detect rainfall events. The FAR index showed an average of 8% for V6 and 9% for CMORPH; 13% for V7, and 15% for Real Time, what is considered reasonable. In the qualitative assessment, we have emphasized the CMORPH product, which showed the best analysis results. This probably happens for being a method that uses more sources of information or for exploring this information more efficiently somehow. In the predictive potential evaluation, Real Time product had the worst results (NSE). V7 resulted in a small decrease of quality when compared to V6, although it was superior in other aspects. CMORPH overcame the other products, with an NSE average of 0.45. In the quantitative assessment, we have noted that V6 and CMORPH could estimate less than 50% of the total rainfall; V7 overestimated around 11% the total rainfall, while Real Time overestimated around 25% of the total. Despite the reasonable results, all the products showed good correlation (0.73). This made us try a method to improve the detection rate. Through modified double-mass equation, we had really significant improvements, except for V7. For instance, for the detection percentage of rainfall events > 60 millimeters, the V6 was almost null 1%; 41% for Real Time; and 1.1% for CMORPH. After the application of the improved method, the detection percentage increased to 53.6%, 50.8%, and 54.8% for those products respectively. These results indicate that the satellite rainfall estimates are an alternative source of data with a great spatial and temporal potential. Thus, the products can be improved to help the hydrological monitoring, mainly in areas with low quality of precipitation data. However, there are still many things to be improved about rainfall estimates, mainly in detecting rainfall, where we have found the biggest limitations.
O continuo aumento na utilização de estimativas de precipitações utilizando dados de satélites, como fonte alternativa de dados tem aumentado com o avanço tecnológico dos dispositivos . Consequentemente aumenta a necessidade de avaliar a qualidade e a precisão dessas estimativas. Neste trabalho foram avaliados os produtos do satélite TRMM (3B42 V6, 3B42 V7 e 3B42 Real Time) e do método CMORPH (produto RAW) utilizando dados observados de precipitação da região da bacia do Alto Jacuí - RS. Para a avaliação foram utilizadas as estatísticas para validação da chuva estimada por satélite recomendadas pelo IPWG, como os índices de desempenho PC (percent correct), H (hits), FAR (false alarm ratio), CSI (critical success índex) entre outros, avaliando o desempenho dos produtos na detecção da ocorrência e na não ocorrência dos eventos. Além de estatísticas básicas, foram empregadas as quantitativas, como erro médio (EM), erro médio quadrático (EMQ), coeficiente de correlação (r), erro no volumes e coeficiente de eficiência Nash-Sutcliffe (NS). A partir dos resultados foi ainda ensaiada uma metodologia para melhora dos resultados. O índice que mede o acerto na estimativa da ocorrência (ou não) de chuvas (PC) apresentou média de 81,3%, e mostrou equilíbrio entre os produtos. Já o índice H, que indica se o satélite simplesmente acertou a chuva (e não dias sem chuva) indicou 60% de acertos, ou seja, a principal dificuldade encontrada por todos os produtos é sem dúvidas na capacidade de detecção dos eventos chuvosos. O índice que avalia o percentual de falsos alarmes (FAR), emitido pelas estimativas apresentou 8% e 9% para os produtos V6 e CMORPH respectivamente, 13% para o V7 e 15% para o Real Time sendo considerado razoável. Na avaliação qualitativa destacou-se o produto CMORPH, que obteve os melhores resultados na análise, e, provavelmente por se tratar de um método híbrido que utiliza o maior número de fontes de informações ou, de alguma forma, as explora de forma mais eficiente. Na avaliação sobre o potencial preditivo, o produto Real Time apresentou os piores resultados (Nash-Sutcliffe), ou seja, é mais vantajoso utilizar a média diária observada do que suas estimativas. O V7 resultou em um leve decréscimo da qualidade quando comparado com o V6, embora tenha se mostrado superior em outros aspectos. E novamente, o CMORPH superou os demais produtos, com coeficientes na ordem média de 0,45. Na parte quantitativa das estimativas dos produtos, notou-se grande subestimativa pelos produtos V6 e CMORPH, e superestimativa leve pelos produtos Real Time e V7, porém os produtos apresentaram boas correlações (r), resultando em uma média de 0,73. Nas comparações das médias mensais que apesar dos erros (sub ou superestimativa), os produtos se mostraram capazes de detectar a variabilidade mensal durante o ano (exceto o Real Time). Através da equação dos confrontos acumulados das séries, ao aplicar uma metodologia de correção da chuva simplificada, obtiveram-se aumentos bastante satisfatórios nos percentuais de detecções (com exceção do produto V7). Principalmente para volumes iguais ou superiores a 60 milímetros, dos quais quase nulos 1% eram detectados pelo V6, 41% pelo Real Time e apenas 1,1% pelo CMORPH, e após os ajustes aumentaram para 53,6%, 50,8 e 54,8% respectivamente. Estes resultados indicam que as estimativas de satélite são uma fonte alternativa de dados com grande qualidade temporal e espacial, fundamental para auxiliar o monitoramento hidrológico. No entanto, ainda existe muito espaço para melhoras nas estimativas de precipitação, principalmente no quesito detecção de eventos, o qual foi o principal responsável pelo decréscimo da qualidade das estimativas no estudo.
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Djenidi, Brahim Fayçal. "Caractérisation moléculaire et fonctionnelle des lymphocytes T CD8+/CD103+ infiltrant les tumeurs pulmonaires humaines." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA11T044/document.
Full textAbstract:
L’immunothérapie se présente aujourd’hui comme une alternative de choix dans le traitement des cancers. Son objectif est d’amplifier la réponse immunitaire contre les cellules tumorales tout en préservant les cellules normales. Les travaux antérieurs de mon équipe ont démontré qu'une réponse immunitaire antitumorale a lieu dans les carcinomes bronchiques non à petites cellules (CBNPC) et que des lymphocytes T cytotoxiques (CTL) spécifiques peuvent contribuer à la régression de la tumeur. Les travaux de mon équipe ont démontré aussi que l’interaction de l’intégrine CD103, souvent exprimée sur les lymphocytes infiltrant la tumeur (TIL), avec son ligand, le marqueur des cellules épithéliales E-Cadhérine, à la surface des cellules tumorales, est nécessaire à la polarisation des granules cytotoxiques et leur exocytose pour déclencher la lyse de la cellule cible. L’objectif principal de mon projet de thèse est de déterminer la contribution réelle des lymphocytes T CD8+/CD103+ infiltrant les tumeurs épithéliales dans la réponse CTL antitumorale et le rôle de CD103 dans la régulation de leurs fonctions effectrices in situ. Dans un premier temps, j’ai caractérisé, sur le plan transcriptionel et phénotypique, les TIL de CBNPC humains. Mes résultats ont montré que les lymphocytes T CD8+/CD103+ présentent une signature moléculaire caractéristique des cellules T mémoires résidentes dans les tissues (TRM), avec une expression des récepteurs CD69 et CD45RO. Mes résultats ont montré aussi que cette population lymphocytaire co-Exprime les récepteurs inhibiteurs PD-1 et Tim-3. Dans un deuxième temps, j’ai étudié la fonctionnalité des TIL CD8+/CD103+ et le rôle de CD103 dans leur activité cytotoxique anti-Tumorale. Mes résultats ont d’abord indiqué que les lymphocytes T CD103+ sont plus sensibles à la mort cellulaire induite par activation (AICD) que les TIL CD103-, et qu’ils expriment le granzyme B et CD107a suite à une activation spécifique. De plus, ils sont capables d’exercer une activité cytotoxique spécifique à l’encontre des cellules tumorales autologues suite à la neutralisation de l’interaction de PD-1 avec son PD-L1, et que des anticorps anti-CD103 bloquants inhibe cette fonction. Ensuite, j’ai analysé l’impact de l’expression de CD103 à la surface des TIL sur la survie de patients atteints de CBNPC de stade 1. Mes résultats ont révélé que cette intégrine favorise l’infiltration des TIL dans les régions tumorales épithéliales et qu’une forte expression de CD103 sur les TIL corrèle avec une amélioration de la survie des patients. Enfin, J’ai examiné le rôle de CD103 dans cette fonction et dans la réponse immunitaire antitumorale in vivo. Mes résultats préliminaires ont montré une croissance tumorale retardée des tumeurs LL2 transfectées avec l’E-Cadhérine et CCL5 greffées dans les souris CD103-WT. De plus l’inhibition de cette croissance corrèle avec une infiltration plus importante des tumeurs avec des lymphocytes T CD8+/CD103+. Ces résultats suggèrent un rôle important de la coexpression de CCL5 et d’E-Cadhérine par la tumeur dans le recrutement et la rétention des CTL au site tumoral. L’ensemble de ces travaux est en faveur du rôle important de CD103 dans la régulation de l’immunité T CD8 dans les tumeurs épithéliales et de l’utilité des anticorps neutralisants anti-PD-1 et anti-Tim-3 pour inverser l'épuisement de cette population lymphocytaires CD8+/CD103+Today Immunotherapy is clearly an alternative choice in the treatment of cancers. Its main objective is to enhance the cytotoxic immune response against tumor cells while preserving normal cells. We have previously demonstrated that there is an antitumor immune response in the Non-Small-Cell lung carcinoma (NSCLC) and cytotoxic T lymphocytes (CTL) contribute to NSCLC tumor regression. We further showed that the CD103 integrin interaction (oftenly expressed on tumor infiltrating lymphocytes (TIL)) with its ligand, the epithelial cell marker E-Cadherin, expressed at the surface of tumor cells, is necessary for the polarization and exocytosis of TIL cytotoxic granules and to trigger the lysis of the tumor target cells. The main purpose of my thesis project is to determine the actual role/ contribution of CD8+/CD103+ T lymphocytes (infiltrating the epithelial tumors) in the regulation of antitumor CTL response and to study the role of CD103 in the regulation of their in situ effector functions. Firstly, TIL infiltrating human NSCLC were characterized at transcriptional and phenotypic level. My results show that CD8+/CD103+ T lymphocytes have a molecular signature characteristic of memory T cells resident in tissues (MRT), with expression of CD69 receptors and CD45RO. My results also showed that this cell population co-Expresses the inhibitory receptors, PD-1 and Tim-3.In a second step, I studied the functionality of CD8+/CD103+ TIL and the role of CD103 in the regulation of anti-Tumor cytotoxic activity. My results have first indicated that CD103+ TIL are more sensitive to activation induced cell death (AICD) than TIL-CD103- and CD103+ TIL express granzyme B and CD107a after specific activation. Furthermore, CD103+ TIL are able to exert a specific cytotoxic activity against autologous tumor cells following the neutralization of PD-1- PD-L1 interaction, and that of anti-CD103 antibody inhibits this blocking function. After, I analyzed the impact of the expression of CD103 on the surface of TIL on the survival of patients with NSCLC stage 1. My results revealed that this integrin promotes the infiltration of TIL in epithelial tumor regions and a strong expression of CD103 on TIL correlates with improved patient survival. Finally, I examined the role of CD103 in this function and the antitumor immune response in vivo. My preliminary results showed a tumor growth delay of LL2 tumors transfected with E-Cadherin and CCL5 grafted in CD103-WT mice. Furthermore inhibition of growth correlates with a higher tumor infiltrating with CD8+/CD103+ T lymphocytes. These results suggest an important role of the coexpression of CCL5 and E-Cadherin by the tumor in the recruitment and retention of CTL at the tumor site. The whole work supports the role of CD103 in regulating the CD8 T cells-Mediated immune response in epithelial tumors and the usefulness of anti-PD-1 neutralizing and anti-Tim-3 for reversing the depletion of this lymphocyte population CD8+ / CD103+