949 resultados para Funder, David C
Resumo:
Este estudo compara a resposta de uma comunidade aves à exploração madeireira de baixo impacto através da distribuição das espécies em floresta controle e manejada ao longo de cinco anos com amostragem pré e pós-exploração. O procedimento de ordenação mostrou que a similaridade da comunidade de aves após a exploração madeireira foi menor que a similaridade entre as amostras do período de pré-exploração. Além disso, a ordem das abundâncias das 43 espécies mais comuns foi alterada entre o período anterior à exploração e 3 a 4 anos após a exploração na floresta manejada. A exploração afetou as taxas de captura de 20 espécies, diretamente ou através de uma interação com o tempo. Os insetívoros terrícolas e os insetívoros que seguem bandos mistos foram as guildas mais afetadas pela exploração madeireira. Ambas as guildas mostraram declínio, correlacionado com o tempo, em suas abundâncias em floresta manejada. Insetívoros seguidores de formigas e insetívoros arborícolas não apresentaram diferenças entre a floresta manejada e controle, apesar de algumas espécies dessas guildas terem apresentado efeitos relacionados ao manejo florestal, diretamente ou através de uma interação entre o tempo e o manejo. Frugívoros também não apresentaram efeitos significativos relacionados ao manejo florestal. Nectarívoros aumentaram tanto na floresta explorada como na floresta controle. Efeitos temporais de aumento ou declínio observados em guildas e em 12 espécies ocorreram tanto na floresta controle como na floresta explorada. Este resultado sugere que mudanças temporais na área explorada podem estar relacionadas à sucessão enquanto que mudanças temporais na floresta controle podem estar relacionados à exploração com intensidade de 40m³/ha de parcelas adjacentes.
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A high-resolution mtDNA phylogenetic tree allowed us to look backward in time to investigate purifying selection. Purifying selection was very strong in the last 2,500 years, continuously eliminating pathogenic mutations back until the end of the Younger Dryas (∼11,000 years ago), when a large population expansion likely relaxed selection pressure. This was preceded by a phase of stable selection until another relaxation occurred in the out-of-Africa migration. Demography and selection are closely related: expansions led to relaxation of selection and higher pathogenicity mutations significantly decreased the growth of descendants. The only detectible positive selection was the recurrence of highly pathogenic nonsynonymous mutations (m.3394T>C-m.3397A>G-m.3398T>C) at interior branches of the tree, preventing the formation of a dinucleotide STR (TATATA) in the MT-ND1 gene. At the most recent time scale in 124 mother-children transmissions, purifying selection was detectable through the loss of mtDNA variants with high predicted pathogenicity. A few haplogroup-defining sites were also heteroplasmic, agreeing with a significant propensity in 349 positions in the phylogenetic tree to revert back to the ancestral variant. This nonrandom mutation property explains the observation of heteroplasmic mutations at some haplogroup-defining sites in sequencing datasets, which may not indicate poor quality as has been claimed.
Resumo:
El trabajo apunta a determinar el origen y naturaleza de las estrellas de C deficientes en H y por lo tanto, su relación con las restantes estrellas de nuestra galaxia. Apunta a determinar la edad y el estado evolutivo de estas estrellas. En lo que se refiere a las atmósferas, se trata de desarrollar una rutina que calcule en forma automática un modelo, tomando debidamente en cuenta las dificultades del problema (apartamiento de LTE, transporte convectivo, etc.), de modo de poderlo aplicar al estudio e interpretación de los espectros de las estrellas HdC. Objetivos Contribuye a clarificar la naturaleza de las estrellas HdC: 1. Una correcta identificación de las estrellas de esta clase por las características que presentan sus espectros. 2. Determinar la abundancia de los distintos elementos en sus atmósferas. 3. Determinar su luminosidad intrínseca. 4. Poder decidir cuáles son las características cinemáticas del grupo. Dentro del tema de las atmósferas estelares, es de interés contar con una rutina que sobre la base de ciertos datos básicos (temperatura efectiva, composición química y gravedad superficial) calcule un modelo con un mínimo de intervención externa. Con este elemento disponible, hay temas interesantes que se están investigando dentro del grupo, como formación de líneas del He en estrellas B con atmósferas extendidas (en presencia de un viento estelar y de una cromósfera) y la distinta estructura que se debe esperar de una atmósfera de una estrella HdC, a causa de ser el C el siguiente elemento en importancia después del He.
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El estudio de los fenómenos emisivos en estrellas Be es de importancia porque agrega información que puede conducir a mejorar la interpretación de la actividad que existe en la alta atmósfera de estas estrellas. Los procesos que se desean estudiar se refieren a las interacciones entre la estrella Be y la de neutrones que componen un sistema Be emisor de radiación X. Un procedimiento posible consiste en utilizar la información prevista por las líneas de hidrógeno, especialmente la línea H gamma, cuyas variaciones permiten predecir la sucesiva emisión de la radiación X producida durante el pasaje por el periastro de la estrella de neutrones. Esto es válido, probablemente en todos los sistemas de este tipo y es justamente lo que se desea comprobar. Se trata de fenómenos que requieren, para ser analizados adecuadamente, de un eficaz seguimiento de los objetivos que se estudian; con este objeto se solicitarán turnos de observación en el Complejo Astronómico CASLEO (Complejo Astronómico Leoncito, provincia de San Juan) y en la Estación Astrofísica de Bosque Alegre del Observatorio Astronómico de Córdoba. Objetivos generales Estos hechos son de gran interés para el estudio de la física y la dinámica de la transferencia de materia en el periastro y la subsecuente emisión explosiva de radiación X. En consecuencia, si estas explosiones emisivas X están originadas por el movimiento orbital excéntrico, un seguimiento multifrecuencial de estos sistemas en su pasaje alrededor del periastro dará una respuesta a muchos de los problemas que presentan. En las longitudes de ondas ópticas, el seguimiento de estos sistemas durante un período orbital puede dar prueba definitiva de la existencia de indicadores ópticos de la siguiente actividad emisiva de radiación X. Objetivos específicos En una lista de alrededor de 25 sistemas pulsantes en radiación X, varios son TXTS. El propósito de este programa es el de buscar indicadores ópticos de emisión de radiación X en algunos sistemas como son: i) A 0538-66, sistema HXTS con un período de 0.07s, en la Nube Mayor de Magallanes. (...) ii) A 1118-615: éste es un sistema SXTS con un período de 405s. (...)
Resumo:
The application of two approaches for high-throughput, high-resolution X-ray phase contrast tomographic imaging being used at the tomographic microscopy and coherent radiology experiments (TOMCAT) beamline of the SLS is discussed and illustrated. Differential phase contrast (DPC) imaging, using a grating interferometer and a phase-stepping technique, is integrated into the beamline environment at TOMCAT in terms of the fast acquisition and reconstruction of data and the availability to scan samples within an aqueous environment. A second phase contrast method is a modified transfer of intensity approach that can yield the 3D distribution of the decrement of the refractive index of a weakly absorbing object from a single tomographic dataset. The two methods are complementary to one another: the DPC method is characterised by a higher sensitivity and by moderate resolution with larger samples; the modified transfer of intensity approach is particularly suited for small specimens when high resolution (around 1 mu m) is required. Both are being applied to investigations in the biological and materials science fields.
Resumo:
OBJECTIVES To investigate the role of factors that modulate the association between alcohol and mortality, and to provide estimates of absolute risk of death. DESIGN The European Prospective Investigation into Cancer and nutrition (EPIC). SETTING 23 centres in 10 countries. PARTICIPANTS 380 395 men and women, free of cancer, diabetes, heart attack or stroke at enrolment, followed up for 12.6 years on average. MAIN OUTCOME MEASURES 20 453 fatal events, of which 2053 alcohol-related cancers (ARC, including cancers of upper aerodigestive tract, liver, colorectal and female breast), 4187 cardiovascular diseases/coronary heart disease (CVD/CHD), 856 violent deaths and injuries. Lifetime alcohol use was assessed at recruitment. RESULTS HRs comparing extreme drinkers (≥30 g/day in women and ≥60 g/day in men) to moderate drinkers (0.1-4.9 g/day) were 1.27 (95% CI 1.13 to 1.43) in women and 1.53 (1.39 to 1.68) in men. Strong associations were observed for ARC mortality, in men particularly, and for violent deaths and injuries, in men only. No associations were observed for CVD/CHD mortality among drinkers, whereby HRs were higher in never compared to moderate drinkers. Overall mortality seemed to be more strongly related to beer than wine use, particularly in men. The 10-year risks of overall death for women aged 60 years, drinking more than 30 g/day was 5% and 7%, for never and current smokers, respectively. Corresponding figures in men consuming more than 60 g/day were 11% and 18%, in never and current smokers, respectively. In competing risks analyses, mortality due to CVD/CHD was more pronounced than ARC in men, while CVD/CHD and ARC mortality were of similar magnitude in women. CONCLUSIONS In this large European cohort, alcohol use was positively associated with overall mortality, ARC and violent death and injuries, but marginally to CVD/CHD. Absolute risks of death observed in EPIC suggest that alcohol is an important determinant of total mortality.
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In epidemiologic studies, measurement error in dietary variables often attenuates association between dietary intake and disease occurrence. To adjust for the attenuation caused by error in dietary intake, regression calibration is commonly used. To apply regression calibration, unbiased reference measurements are required. Short-term reference measurements for foods that are not consumed daily contain excess zeroes that pose challenges in the calibration model. We adapted two-part regression calibration model, initially developed for multiple replicates of reference measurements per individual to a single-replicate setting. We showed how to handle excess zero reference measurements by two-step modeling approach, how to explore heteroscedasticity in the consumed amount with variance-mean graph, how to explore nonlinearity with the generalized additive modeling (GAM) and the empirical logit approaches, and how to select covariates in the calibration model. The performance of two-part calibration model was compared with the one-part counterpart. We used vegetable intake and mortality data from European Prospective Investigation on Cancer and Nutrition (EPIC) study. In the EPIC, reference measurements were taken with 24-hour recalls. For each of the three vegetable subgroups assessed separately, correcting for error with an appropriately specified two-part calibration model resulted in about three fold increase in the strength of association with all-cause mortality, as measured by the log hazard ratio. Further found is that the standard way of including covariates in the calibration model can lead to over fitting the two-part calibration model. Moreover, the extent of adjusting for error is influenced by the number and forms of covariates in the calibration model. For episodically consumed foods, we advise researchers to pay special attention to response distribution, nonlinearity, and covariate inclusion in specifying the calibration model.
Resumo:
BACKGROUND Obesity is positively associated with colorectal cancer. Recently, body size subtypes categorised by the prevalence of hyperinsulinaemia have been defined, and metabolically healthy overweight/obese individuals (without hyperinsulinaemia) have been suggested to be at lower risk of cardiovascular disease than their metabolically unhealthy (hyperinsulinaemic) overweight/obese counterparts. Whether similarly variable relationships exist for metabolically defined body size phenotypes and colorectal cancer risk is unknown. METHODS AND FINDINGS The association of metabolically defined body size phenotypes with colorectal cancer was investigated in a case-control study nested within the European Prospective Investigation into Cancer and Nutrition (EPIC) study. Metabolic health/body size phenotypes were defined according to hyperinsulinaemia status using serum concentrations of C-peptide, a marker of insulin secretion. A total of 737 incident colorectal cancer cases and 737 matched controls were divided into tertiles based on the distribution of C-peptide concentration amongst the control population, and participants were classified as metabolically healthy if below the first tertile of C-peptide and metabolically unhealthy if above the first tertile. These metabolic health definitions were then combined with body mass index (BMI) measurements to create four metabolic health/body size phenotype categories: (1) metabolically healthy/normal weight (BMI < 25 kg/m2), (2) metabolically healthy/overweight (BMI ≥ 25 kg/m2), (3) metabolically unhealthy/normal weight (BMI < 25 kg/m2), and (4) metabolically unhealthy/overweight (BMI ≥ 25 kg/m2). Additionally, in separate models, waist circumference measurements (using the International Diabetes Federation cut-points [≥80 cm for women and ≥94 cm for men]) were used (instead of BMI) to create the four metabolic health/body size phenotype categories. Statistical tests used in the analysis were all two-sided, and a p-value of <0.05 was considered statistically significant. In multivariable-adjusted conditional logistic regression models with BMI used to define adiposity, compared with metabolically healthy/normal weight individuals, we observed a higher colorectal cancer risk among metabolically unhealthy/normal weight (odds ratio [OR] = 1.59, 95% CI 1.10-2.28) and metabolically unhealthy/overweight (OR = 1.40, 95% CI 1.01-1.94) participants, but not among metabolically healthy/overweight individuals (OR = 0.96, 95% CI 0.65-1.42). Among the overweight individuals, lower colorectal cancer risk was observed for metabolically healthy/overweight individuals compared with metabolically unhealthy/overweight individuals (OR = 0.69, 95% CI 0.49-0.96). These associations were generally consistent when waist circumference was used as the measure of adiposity. To our knowledge, there is no universally accepted clinical definition for using C-peptide level as an indication of hyperinsulinaemia. Therefore, a possible limitation of our analysis was that the classification of individuals as being hyperinsulinaemic-based on their C-peptide level-was arbitrary. However, when we used quartiles or the median of C-peptide, instead of tertiles, as the cut-point of hyperinsulinaemia, a similar pattern of associations was observed. CONCLUSIONS These results support the idea that individuals with the metabolically healthy/overweight phenotype (with normal insulin levels) are at lower colorectal cancer risk than those with hyperinsulinaemia. The combination of anthropometric measures with metabolic parameters, such as C-peptide, may be useful for defining strata of the population at greater risk of colorectal cancer.
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X-ray imaging with grating interferometry has previously been regarded as a technique providing information only in direct space. It delivers absorption, phase, and dark-field contrast, which can be viewed as parameters of the underlying but unresolved scattering distribution. Here, we present a method that provides the ultrasmall-angle x-ray scattering distribution and, thus, allows simultaneous access to direct and reciprocal space information.
Resumo:
The aim of this work was to evaluate the energy flows of a commercial production system of swine deep bed in its finishing phase, located in Juiz de Fora, in the State of Minas Gerais, Brazil. Thus, an energy efficiency study was carried out by monitoring a lot of animals, during a 94-day period. The energy rate of each compound involved in the production process was quantified and the matrixes of energy consumption were determined in the form of animal feeding, electrical energy, piglets, material used as deep bed, human labor, equipment, swine buildings, production of alive swine for slaughter, organic fertilizer production (swine deep bed or swine deep litter). From the direct input energy, 80.57% correspond to animal feeding, 11.90% to pigs for slaughter and 6.76% to piglets, while from the energy output 53.45% correspond to the terminating swine and 46.55% to organic fertilizer (swine deep bed). By the results obtained, we can conclude that such production system has corresponded to an industrial and highly specialized agro ecosystem, importing a great part of the energy consumed in the production process, with 41% of energy efficiency.
Resumo:
L’ADÉQUATION ENTRE LES BESOINS VÉCUS PAR LES PROCHES DE PERSONNES AYANT UN TRAUMATISME CRÂNIEN ET LES SERVICES OFFERTS PAR LE CONTINUUM DE SOINS ~ Sommaire exécutif ~ SOUS LA DIRECTION D’HÉLÈNE LEFEBVRE, PH.D. Programme de recherche en réadaptation et intégration sociale en traumatologie DÉCEMBRE 2007
Resumo:
La recherche sur les questions touchant aux leaders de groupes sectaires et à la violence sectaire a mené à l’étude du rôle joué par l’autorité charismatique, tel que défini par Weber (1922) et repris par Dawson (2010). À ce sujet, d’éminents spécialistes des études sur les sectes sont d’avis qu’un vide important dans la recherche sur l’autorité charismatique dans le contexte de groupes sectaires et de nouveaux mouvements religieux reste à combler (ajouter les références ‘d’éminents spécialistes’). Ce mémoire vise à contribuer à l’étude cet aspect négligé, le rôle de l’autorité charismatique dans le recours è la violence dans les groupes sectaires, par une étude de cas historique d’un groupe de la Réformation protestante du XVIe siècle, le Royaume anabaptiste de Münster (AKA), sous l’influence d’un leader charismatique, Jan van Leiden. Cette recherche s’intéresse plus spécifiquement aux divers moyens utilisés par Jan van Leiden, pour asseoir son autorité charismatique et à ceux qui ont exercé une influence sur le recours à des actes de violence. L’étude de cas est basé sur le matériel provenant de deux comptes-rendus des faits relatés par des participants aux événements qui se sont déroulés à pendant le règne de Leiden à la tête du AKA. L’analyse du matériel recueilli a été réalisé à la lumière de trois concepts théoriques actuels concernant le comportement cultuel et le recours à la violence.. L’application de ces concepts théoriques a mené à l’identification de quatre principales stratégies utilisées par Jan van Leiden pour établir son autorité charismatique auprès de ses disciples, soit : 1) la menace du millénarisme, 2) l’exploitation d’une relation bilatérale parasitique avec ses disciples, 3) l’utilisation de l’extase religieuse et de la prophétie, 4) l’utilisation du désir de voir survenir des changements sociaux et religieux. En plus de ces quatre stratégies, trois autres dimensions ont été retenues comme signes que le recours à la violence dans le Royaume anabaptiste de Münster résultait de l’établissement de l’autorité charismatique de son leader, soit : 1) la violence liée au millénarisme, 2) la notion d’identité et de violence partagée, 3) des facteurs systémiques, physiques et culturels menant à la violence.
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Le 27 mai 1406, le théologien parisien Pierre Plaoul comparaît devant la cour du Parlement de Paris en tant que représentant de l’Université de Paris dans une affaire qui l’oppose à l’Université de Toulouse. Il y prononce un sermon en latin, ce que la cour lui reproche instantanément, lui demandant de parler en français pour la prochaine séance. Le 7 juin, lors de sa deuxième comparution, il parle cette fois en langue vernaculaire et prononce un discours extrêmement différent du premier, autant dans son genre que dans son registre de citations. Les deux discours sont conservés dans le registre X1a4787 des Archives nationales de France. L’édition des discours permet de comprendre le raisonnement derrière leurs différences, mais il permet surtout de constater que le discours français fait état d’une érudition encore plus grande que son homologue latin et que son orateur n’était nullement gêné par l’usage de la langue vernaculaire. Remis dans le contexte historiographique actuel, il en ressort que l’utilisation du français par Plaoul concorde parfaitement avec l’abandon du modèle de rapport diglossique entre latin et français pour la fin du Moyen Âge, lui préférant plutôt un rapport de langues en contacts. Ce postulat est soutenu par les nombreuses occurrences d’universitaires médiévaux démontrant une excellente maîtrise d’un registre savant de la langue vulgaire, des poètes, aux prédicateurs en passant par les practiciens du droit. Un examen plus attentif de l’utilisation de la langue française par les docteurs en théologie du règne de Charles VI vient aussi appuyer l’hypothèse selon laquelle les universitaires du bas Moyen Âge considéraient la langue vernaculaire comme un instrument approprié à la transmission de la culture savante.