976 resultados para D. Frei Manuel Coutinho


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The evaluation of the quality and usefulness of climate modeling systems is dependent upon an assessment of both the limited predictability of the climate system and the uncertainties stemming from model formulation. In this study a methodology is presented that is suited to assess the performance of a regional climate model (RCM), based on its ability to represent the natural interannual variability on monthly and seasonal timescales. The methodology involves carrying out multiyear ensemble simulations (to assess the predictability bounds within which the model can be evaluated against observations) and multiyear sensitivity experiments using different model formulations (to assess the model uncertainty). As an example application, experiments driven by assimilated lateral boundary conditions and sea surface temperatures from the ECMWF Reanalysis Project (ERA-15, 1979–1993) were conducted. While the ensemble experiment demonstrates that the predictability of the regional climate varies strongly between different seasons and regions, being weakest during the summer and over continental regions, important sensitivities of the modeling system to parameterization choices are uncovered. In particular, compensating mechanisms related to the long-term representation of the water cycle are revealed, in which summer dry and hot conditions at the surface, resulting from insufficient evaporation, can persist despite insufficient net solar radiation (a result of unrealistic cloud-radiative feedbacks).

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1. Litter decomposition recycles nutrients and causes large fluxes of carbon dioxide into the atmosphere. It is typically assumed that climate, litter quality and decomposer communities determine litter decay rates, yet few comparative studies have examined their relative contributions in tropical forests. 2. We used a short-term litterbag experiment to quantify the effects of litter quality, placement and mesofaunal exclusion on decomposition in 23 tropical forests in 14 countries. Annual precipitation varied among sites (760-5797 mm). At each site, two standard substrates (Raphia farinifera and Laurus nobilis) were decomposed in fine- and coarse-mesh litterbags both above and below ground for approximately 1 year. 3. Decomposition was rapid, with >95% mass loss within a year at most sites. Litter quality, placement and mesofaunal exclusion all independently affected decomposition, but the magnitude depended upon site. Both the average decomposition rate at each site and the ratio of above- to below-ground decay increased linearly with annual precipitation, explaining 60-65% of among-site variation. Excluding mesofauna had the largest impact on decomposition, reducing decomposition rates by half on average, but the magnitude of decrease was largely independent of climate. This suggests that the decomposer community might play an important role in explaining patterns of decomposition among sites. Which litter type decomposed fastest varied by site, but was not related to climate. 4. Synthesis. A key goal of ecology is to identify general patterns across ecological communities, as well as relevant site-specific details to understand local dynamics. Our pan-tropical study shows that certain aspects of decomposition, including average decomposition rates and the ratio of above- to below-ground decomposition are highly correlated with a simple climatic index: mean annual precipitation. However, we found no relationship between precipitation and effects of mesofaunal exclusion or litter type, suggesting that site-specific details may also be required to understand how these factors affect decomposition at local scales.

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Interspecies interactions of the nasopharyngeal microbiota are likely to be involved in the pathogenesis of acute otitis media (AOM). Capturing the breadth of microbial interactions requires a detailed description of the microbiota during health and AOM.

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A novel non-culture based 16S rRNA Terminal Restriction Fragment Length Polymorphism (T-RFLP) method using the restriction enzymes Tsp509I and Hpy166II was developed for the characterization of the nasopharyngeal microbiota and validated using recently published 454 pyrosequencing data. 16S rRNA gene T-RFLP for 153 clinical nasopharyngeal samples from infants with acute otitis media (AOM) revealed 5 Tsp509I and 6 Hpy166II terminal fragments (TFs) with a prevalence of >10%. Cloning and sequencing identified all TFs with a prevalence >6% allowing a sufficient description of bacterial community changes for the most important bacterial taxa. The conjugated 7-valent pneumococcal polysaccharide vaccine (PCV-7) and prior antibiotic exposure had significant effects on the bacterial composition in an additive main effects and multiplicative interaction model (AMMI) in concordance with the 16S rRNA 454 pyrosequencing data. In addition, the presented T-RFLP method is able to discriminate S. pneumoniae from other members of the Mitis group of streptococci, which therefore allows the identification of one of the most important human respiratory tract pathogens. This is usually not achieved by current high throughput sequencing protocols. In conclusion, the presented 16S rRNA gene T-RFLP method is a highly robust, easy to handle and a cheap alternative to the computationally demanding next-generation sequencing analysis. In case a lot of nasopharyngeal samples have to be characterized, it is suggested to first perform 16S rRNA T-RFLP and only use next generation sequencing if the T-RFLP nasopharyngeal patterns differ or show unknown TFs.

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von M. Joel

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M. Nuél [d.i. Manuel Schnitzer]

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El origen del trabajo desarrollado surgió como resultado de una serie de conversaciones mantenidas con mi director de tesina D. José Manuel Ballesteros, al que manifesté mi interés en realizarlo sobre el tema de Atletismo Femenino Español de tal manera, que especulando con los diversos tratamientos posibles sobre el mismo, optamos por el que se hace referencia en el título, es decir, presentando su origen y evolución en función de las marcas, mediante un estudio comparativo a través de los rankings nacionales, y listas de records de la I.A.A.F. y las "categorías" de atletas de la R.F.E.A. La otra razón, de no menor relieve, ha sido la falta de interés general, que por el atletismo femenino existe entre nosotros tanto a nivel popular como a nivel de los especialistas. La mayor parte de los trabajos existentes sobre atletismo se han restringido preferentemente a la categoría masculina, por lo que se nos ofrece una misión capidisminuída del panorama atlético, al no integrarse en ellos la parte que corresponde interpretar en su contexto general, a nuestras altelas; por todo esto cabe preguntarse: ¿no será que el papel de la mujer en nuestra sociedad sigue siendo poco valorado, y de ahí, que sus actividades no sean dignas de tenerse en cuenta? Más en particular, refiriendo lo anteriormente expuesto a nuestra parcela, ¿es el papel ¿le nuestras atletas poco apreciado en nuestro panorama atlético?, o bien: ¿carecerá realmente de importancia el movimiento atlético femenino en nuestro país, como para no ser apreciado por la mayoría de los estudiosos de este deporte?. Las relaciones entre el prejuicio hacía la práctica del deporte femenino y la calidad del mismo, parecen ser bastante estrechas, pues, la creencia muy generalizada de achacar a la práctica de ciertos deportes, y en especial al atletismo una masculinización de la mujer, tomando como ejemplo los casos personalismos de atletas extranjeras que, como excepción confirman la regla, ya sea por su complexión morfológica de rasgos acusadamente varoniles, o bien por la insidiosa interpretación que se ha hecho sobre casos de "atletas" cuyos caracteres sexuales eran ambiguos, prestándose a la suplantación de sexo, y que hace algunos años aparecieron en reducido número, pero con gran publicidad de los mismos, sin que en la actualidad puedan darse tales casos debido a los controles médicos que se realizan. El problema presentado es muy interesante y amplio, pero con todo me voy a limitar a un aspecto concreto del problema en general, que se adapta mejor a mis posibilidades de investigación sobre el particular, ya que mi intención es comprobar la dimensionalidad alcanzada por el Atletismo Femenino Español de la época actual, a través del estudio analítico desarrollado en función de las marcas como referencia más válida para constatar el desarrollo evolutivo del mismo, deduciéndose se ha existido progreso, y por lo tanto, si éste, carece o no de importancia, marcándonos este estudio y sus resultados el valor real del fenómeno en cuestión. Debido a poder considerar, en un plano, cuando menos, teórico la existencia de dos fases o época en el atletismo femenino español, según se ha dado cuente en el apartado primero de este capítulo, se ha optado, por la que tanto por su valor como por la adquisición de un auténtico cuerpo formal, siendo además la actual permite enlazar menor con el futuro.