953 resultados para Ecological Processes


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Nascent sex chromosomes offer a unique opportunity to investigate the evolutionary fate of genesrecently trapped in non-recombining segments. A housekeeping gene (MED15) was recently shown to lie on the nascent sex-chromosomes of the European tree frog (Hyla arborea), with different alleles fixed on the X and the Y chromosomes. Here we document a polymorphism (glutamine deletion) in the X copy of the gene, and use population surveys and experimental crosses to test whether this polymorphism is neutral or maintained by sex-antagonistic selection. Tadpoles from parents of known genotypes revealed significant discrepancies from Mendelian inheritance, suggesting possible sex-antagonistic effects under laboratory conditions. Quantitatively, however, these effects did not meet the conditions for polymorphism maintenance. Furthermore, field estimates of female genotypic frequencies did not differ from Hardy-Weinberg equilibrium and allelic frequencies on the X chromosome did not differ between sexes. In conclusion, although sex antagonistic effects cannot be excluded given the laboratory conditions, the X-linked polymorphism under study appears neutral in the wild. Alternatively, sex-antagonistic selection might still account for the fixation of a male specific allele on the Y chromosome.

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OBJECTIVE Delusional disorder has been traditionally considered a psychotic syndrome that does not evolve to cognitive deterioration. However, to date, very little empirical research has been done to explore cognitive executive components and memory processes in Delusional Disorder patients. This study will investigate whether patients with delusional disorder are intact in both executive function components (such as flexibility, impulsivity and updating components) and memory processes (such as immediate, short term and long term recall, learning and recognition). METHODS A large sample of patients with delusional disorder (n = 86) and a group of healthy controls (n = 343) were compared with regard to their performance in a broad battery of neuropsychological tests including Trail Making Test, Wisconsin Card Sorting Test, Colour-Word Stroop Test, and Complutense Verbal Learning Test (TAVEC). RESULTS When compared to controls, cases of delusional disorder showed a significantly poorer performance in most cognitive tests. Thus, we demonstrate deficits in flexibility, impulsivity and updating components of executive functions as well as in memory processes. These findings held significant after taking into account sex, age, educational level and premorbid IQ. CONCLUSIONS Our results do not support the traditional notion of patients with delusional disorder being cognitively intact.

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Various lines of evidence accumulated over the past 30 years indicate that the cerebellum, long recognized as essential for motor control, also has considerable influence on perceptual processes. In this paper, we bring together experts from psychology and neuroscience, with the aim of providing a succinct but comprehensive overview of key findings related to the involvement of the cerebellum in sensory perception. The contributions cover such topics as anatomical and functional connectivity, evolutionary and comparative perspectives, visual and auditory processing, biological motion perception, nociception, self-motion, timing, predictive processing, and perceptual sequencing. While no single explanation has yet emerged concerning the role of the cerebellum in perceptual processes, this consensus paper summarizes the impressive empirical evidence on this problem and highlights diversities as well as commonalities between existing hypotheses. In addition to work with healthy individuals and patients with cerebellar disorders, it is also apparent that several neurological conditions in which perceptual disturbances occur, including autism and schizophrenia, are associated with cerebellar pathology. A better understanding of the involvement of the cerebellum in perceptual processes will thus likely be important for identifying and treating perceptual deficits that may at present go unnoticed and untreated. This paper provides a useful framework for further debate and empirical investigations into the influence of the cerebellum on sensory perception.

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Introduction: There is little information regarding the impact of diet on disease incidence and mortality in Switzerland. Objectives: We aimed at assessing the associations between food availability and disease using ecological correlations. Methods: Time-trend ecologic study for period 1970 to 2009. Food availability was measured through the FAO food balance sheets. Standardized mortality rates (SMRs) were obtained from the Swiss Federal Office of Statistics. Cancer incidence data was obtained from the WHO Health for all database and the Vaud cancer registry. Association between food availability and mortality/incidence was assessed at lags 0, 5, 10 and 15 years by Spearman correlation. Results: Alcoholic beverages and fruit availability were positively associated with SMRs from all types of cardiovascular disease, while fish availability was negatively associated. Animal products, meat and animal fats were positively associated with SMR from ischemic heart disease only. For cancers, opposite results were found whether the association used SMRs or incidence rates. For all cancers, alcoholic beverages and fruits were positively associated with SMRs but negatively associated with incidence rates. Similar findings were obtained for all other foods, with the exception of vegetables, which were weakly and negatively associated with SMRs and incidence rates. Finally, a 15 years lag time reversed the association for animal and vegetal products, weakened the association for alcohol and fruits and strengthened the association for fish. Conclusion: Ecologic associations between food availability and disease vary considerably whether mortality or incidence rates are used. Great care should be taken when interpreting the results.

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A mesura que el suport del creixement econòmic constitueix un objectiu fonamental de la formulació de polítiques econòmiques, cal assenyalar que aquest tipus de creixement està limitat naturalment per un planeta finit. Aquest article argumenta que, des del punt de vista de la justícia intergeneracional, la realització d'un concepte de desmaterialització i, com a efecte, d'una economia que no creix (en el sentit de dissociació absoluta del creixement econòmic i consum d'energia i materials) es pot justificar. Per tant, el creixement pot ser també entesa com la millora de la qualitat de vida sobretot en comptes d'ampliar quantitats escarpats de sortida. Per tant, una dràstica reducció del cabal de material es necessita, sobretot en els països d'alts ingressos. Després de presentar alguns crítica de les propostes, en el focus d'aquest article es dibuixen en els arguments de per què la política econòmica en el futur han de ser etiquetats com "ecològic" i, a continuació, les opcions de posar en acció les idees del teòric presentat marc en tasques manejables polítiques seran discutides. En aquest cas, s'argumentarà que l'enfocament clàssic de internalització d'efectes externs sovint seguides de decisions de política econòmica ortodoxa no és completament capaç de reflectir canvis ecològics en les estructures de preus dels mercats. Per tant, formal (industrial i l'establiment de la política de consum) i institucions informals (llars) representen punts clau de la política econòmica sostenible, assenyalant l'individu com així com la responsabilitat col · lectiva per omplir aquest buit substancial.

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The aim of this work is to make known the multicentric project AMCAC, whose objective is to describe the geographical distribution of mortality from all causes in census groups of the provincial capitals of Andalusia and Catalonia during 1992-2002 and 1994-2000 respectively, and to study the relationship between the sociodemographic characteristics of the census groups and mortality. This is an ecological study in which the analytical unit is the census group. The data correspond to 298,731 individuals (152,913 men and 145,818 women) who died during the study periods in the towns of Almeria, Barcelona, Cadiz, Cordoba, Girona, Granada, Huelva, Jaen, Lleida, Malaga, Seville and Tarragona during the study periods. The dependent variable is the number of deaths observed per census group. The independent variables are the percentage of unemployment, illiteracy and manual workers. Estimation of the moderated relative risk and the study of the associations among the sociodemographic characteristics of the census groups and the mortality will be done for each town and each sex using the Besag-York-Mollie model. Dissemination of the results will help to improve and broaden knowledge about the population's health, and will provide an important starting point to establish the influence of contextual variables on the health of urban populations.

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Background: Community phylogenetics is an emerging field of research that has made important contributions to understanding community assembly. The rapid development of this field can be attributed to the merging of phylogenetics and community ecology research to provide improved clarity on the processes that govern community structure and composition. Question: What are the major challenges that impede the sound interpretation of the patterns and processes of phylogenetic community assembly? Methods: We use four scenarios to illustrate explicitly how the phylogenetic structure of communities can exist in stable or transient phases, based on the different combinations of phylogenetic relationships and phenotypic traits among co-occurring species. We discuss these phases by implicating a two-way process in the assembly and disintegration of the given ecological community. Conclusions: This paper synthesizes the major concepts of community phylogenetics using habitat filtering and competition processes to elucidate how the understanding of phylogenetic community structure is currently hindered by the dynamics of community assembly and disassembly.

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This file contains the ontology of patterns of educational settings, as part of the formal framework for specifying, reusing and implementing educational settings. Furthermore, it includes the set of rules that extend the ontology of educational scenarios as well as a brief description of the level of patters of such ontological framework.

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The Mg/Ca and Sr/Ca ratios of living ostracods belonging to 15 different species and sampled monthly over a one year-cycle at five sites (2, 5, 13, 33, and 70 m water depths) in western Lake Geneva (Switzerland) are compared to the oxygen and carbon isotope compositions measured on the same samples as well as to the temperature and chemical composition of the water (δ18OH2O, δ13CDIC, Mg/CaH2O, and Sr/CaH2O) at the time of ostracod calcification. The results indicate that trace element incorporation varied at the species level, mainly because of the ecological and biological differences between the different species (life-cycle, (micro-)habitat preference, biomineralisation processes) and the control thereof on trace element incorporation of the ostracods. In littoral zones, the Mg/Ca and Sr/Ca of ostracod valves increase as temperature and Mg/Ca and Sr/Ca of water increase during spring and summer, hence reflecting mainly seasonal variations. However, given that for Lake Geneva the Mg/Ca and Sr/Ca of water also vary with temperature, it is not possible to distinguish the effects of temperature from those of changes in chemical composition of water on the trace element content in ostracod valves. Results support that both water temperature and water Mg/Ca and Sr/Ca ratios control the final trace element content of Cyprididae valves. In contrast, the trace element content of species living in deeper zones of the basin is influenced by variations in the chemical composition of the pore water for the infaunal species. Trace element content measured for these specimens cannot, therefore, be used to reconstruct the compositions of the water lake bottom. In addition, incorporation of Mg and Sr into the shell differs from one family, sub-family, or even species to the other. This suggests that the distinctive Mg and Sr partition coefcients for the analysed taxa result from different valve calcification strategies that may be phylogenetic.

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The chemical composition of sediments and rocks, as well as their distribution at theMartian surface, represent a long term archive of processes, which have formed theplanetary surface. A survey of chemical compositions by means of Compositional DataAnalysis represents a valuable tool to extract direct evidence for weathering processesand allows to quantify weathering and sedimentation rates. clr-biplot techniques areapplied for visualization of chemical relationships across the surface (“chemical maps”).The variability among individual suites of data is further analyzed by means of clr-PCA,in order to extract chemical alteration vectors between fresh rocks and their crusts andfor an assessment of different source reservoirs accessible to soil formation. Bothtechniques are applied to elucidate the influence of remote weathering by combinedanalysis of several soil forming branches. Vector analysis in the Simplex provides theopportunity to study atmosphere surface interactions, including the role andcomposition of volcanic gases

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Les écosystèmes fournissent de nombreuses ressources et services écologiques qui sont utiles à la population humaine. La biodiversité est une composante essentielle des écosystèmes et maintient de nombreux services. Afin d'assurer la permanence des services écosystémiques, des mesures doivent être prises pour conserver la biodiversité. Dans ce but, l'acquisition d'informations détaillées sur la distribution de la biodiversité dans l'espace est essentielle. Les modèles de distribution d'espèces (SDMs) sont des modèles empiriques qui mettent en lien des observations de terrain (présences ou absences d'une espèce) avec des descripteurs de l'environnement, selon des courbes de réponses statistiques qui décrive la niche réalisée des espèces. Ces modèles fournissent des projections spatiales indiquant les lieux les plus favorables pour les espèces considérées. Le principal objectif de cette thèse est de fournir des projections plus réalistes de la distribution des espèces et des communautés en montagne pour le climat présent et futur en considérant non-seulement des variables abiotiques mais aussi biotiques. Les régions de montagne et l'écosystème alpin sont très sensibles aux changements globaux et en même temps assurent de nombreux services écosystémiques. Cette thèse est séparée en trois parties : (i) fournir une meilleure compréhension du rôle des interactions biotiques dans la distribution des espèces et l'assemblage des communautés en montagne (ouest des Alpes Suisses), (ii) permettre le développement d'une nouvelle approche pour modéliser la distribution spatiale de la biodiversité, (iii) fournir des projections plus réalistes de la distribution future des espèces ainsi que de la composition des communautés. En me focalisant sur les papillons, bourdons et plantes vasculaires, j'ai détecté des interactions biotiques importantes qui lient les espèces entre elles. J'ai également identifié la signature du filtre de l'environnement sur les communautés en haute altitude confirmant l'utilité des SDMs pour reproduire ce type de processus. A partir de ces études, j'ai contribué à l'amélioration méthodologique des SDMs dans le but de prédire les communautés en incluant les interactions biotiques et également les processus non-déterministes par une approche probabiliste. Cette approche permet de prédire non-seulement la distribution d'espèces individuelles, mais également celle de communautés dans leur entier en empilant les projections (S-SDMs). Finalement, j'ai utilisé cet outil pour prédire la distribution d'espèces et de communautés dans le passé et le futur. En particulier, j'ai modélisé la migration post-glaciaire de Trollius europaeus qui est à l'origine de la structure génétique intra-spécifique chez cette espèce et évalué les risques de perte face au changement climatique. Finalement, j'ai simulé la distribution des communautés de bourdons pour le 21e siècle afin d'évaluer les changements probables dans ce groupe important de pollinisateurs. La diversité fonctionnelle des bourdons va être altérée par la perte d'espèces spécialistes de haute altitude et ceci va influencer la pollinisation des plantes en haute altitude. - Ecosystems provide a multitude of resources and ecological services, which are useful to human. Biodiversity is an essential component of those ecosystems and guarantee many services. To assure the permanence of ecosystem services for future generation, measure should be applied to conserve biodiversity. For this purpose, the acquisition of detailed information on how biodiversity implicated in ecosystem function is distributed in space is essential. Species distribution models (SDMs) are empirical models relating field observations to environmental predictors based on statistically-derived response surfaces that fit the realized niche. These models result in spatial predictions indicating locations of the most suitable environment for the species and may potentially be applied to predict composition of communities and their functional properties. The main objective of this thesis was to provide more accurate projections of species and communities distribution under current and future climate in mountains by considering not solely abiotic but also biotic drivers of species distribution. Mountain areas and alpine ecosystems are considered as particularly sensitive to global changes and are also sources of essential ecosystem services. This thesis had three main goals: (i) a better ecological understanding of biotic interactions and how they shape the distribution of species and communities, (ii) the development of a novel approach to the spatial modeling of biodiversity, that can account for biotic interactions, and (iii) ecologically more realistic projections of future species distributions, of future composition and structure of communities. Focusing on butterfly and bumblebees in interaction with the vegetation, I detected important biotic interactions for species distribution and community composition of both plant and insects along environmental gradients. I identified the signature of environmental filtering processes at high elevation confirming the suitability of SDMs for reproducing patterns of filtering. Using those case-studies, I improved SDMs by incorporating biotic interaction and accounting for non-deterministic processes and uncertainty using a probabilistic based approach. I used improved modeling to forecast the distribution of species through the past and future climate changes. SDMs hindcasting allowed a better understanding of the spatial range dynamic of Trollius europaeus in Europe at the origin of the species intra-specific genetic diversity and identified the risk of loss of this genetic diversity caused by climate change. By simulating the future distribution of all bumblebee species in the western Swiss Alps under nine climate change scenarios for the 21st century, I found that the functional diversity of this pollinator guild will be largely affected by climate change through the loss of high elevation specialists. In turn, this will have important consequences on alpine plant pollination.

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During more than 20 years organisations like Gesto por la Paz and Lokarri had been trying to change the social approach to violence, instilling values of peace and dialogue. This working paper defends the idea that the work of these two organisations is key to understand the end of ETA violence and the lack of support that political violence has in the Basque Country. It develops the Basque peace frame generated by this movement and explains how this frame is present in the different levels of Basque society, changing the way political collective identities are negotiated in the Basque Country. Ultimately, their effort is to propose another way of doing politics, one where nationalism and violence are not intrinsically united, escaping from the polarization and confrontation that were in place during the 80s-90s.

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The endocannabinoid (eCB) system can promote food intake by increasing odor detection in mice. The eCB system is over-active in human obesity. Our aim is to measure circulating eCB concentrations and olfactory capacity in a human sample that includes people with obesity and explore the possible interaction between olfaction, obesity and the eCB system. The study sample was made up of 161 females with five groups of body mass index sub-categories ranging from under-weight to morbidly obese. We assessed olfactory capacity with the "Sniffin´Sticks" test, which measures olfactory threshold-discrimination-identification (TDI) capacity. We measured plasma concentrations of the eCBs 2-arachidonoylglycerol (2-AG) and N-arachidonoylethanolamine or anandamide (AEA), and several eCB-related compounds, 2-acylglycerols and N-acylethanolamines. 2-AG and other 2-acylglycerols fasting plasma circulating plasma concentrations were higher in obese and morbidly obese subjects. AEA and other N-acylethanolamine circulating concentrations were lower in under-weight subjects. Olfactory TDI scores were lower in obese and morbidly obese subjects. Lower TDI scores were independently associated with higher 2-AG fasting plasma circulating concentrations, higher %body fat, and higher body mass index, after controlling for age, smoking, menstruation, and use of contraceptives. Our results show that obese subjects have a lower olfactory capacity than non-obese ones and that elevated fasting plasma circulating 2-AG concentrations in obesity are linked to a lower olfactory capacity. In agreement with previous studies we show that eCBs AEA and 2-AG, and their respective congeners have a distinct profile in relation to body mass index. The present report is the first study in humans in which olfactory capacity and circulating eCB concentrations have been measured in the same subjects.

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Chronic periaortitis (CP) is an uncommon inflammatory disease which primarily involves the infrarenal portion of the abdominal aorta. However, CP should be regarded as a generalized disease with three different pathophysiological entities, namely idiopathic retroperitoneal fibrosis (RPF), inflammatory abdominal aortic aneurysm and perianeurysmal RPF. These entities share similar histopathological characteristics and finally will lead to fibrosis of the retroperitoneal space. Beside fibrosis, an infiltrate with variable chronic inflammatory cell is present. The majority of these cells are lymphocytes and macrophages as well as vascular endothelial cells, most of which are HLA-DR-positive. B and T cells are present with a majority of T cells of the T-helper phenotype. Cytokine gene expression analysis shows the presence of interleukin (IL)-1alpha, IL-2, IL-4, interferon-gamma and IL-2 receptors. Adhesion molecules such as E-selectin, intercellular adhesion molecule-1 and the vascular cell adhesion molecule-1 were also found in aortic tissue, and may play a significant role in CP pathophysiology. Although CP pathogenesis remains unknown, an exaggerated inflammatory response to advanced atherosclerosis (ATS) has been postulated to be the main process. Autoimmunity has also been proposed as a contributing factor based on immunohistochemical studies. The suspected allergen may be a component of ceroid, which is elaborated within the atheroma. We review the pathogenesis and the pathophysiology of CP, and its potential links with ATS. Clinically relevant issues are summarized in each section with regard to the current working hypothesis of this complex inflammatory disease.

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We present the derivation of the continuous-time equations governing the limit dynamics of discrete-time reaction-diffusion processes defined on heterogeneous metapopulations. We show that, when a rigorous time limit is performed, the lack of an epidemic threshold in the spread of infections is not limited to metapopulations with a scale-free architecture, as it has been predicted from dynamical equations in which reaction and diffusion occur sequentially in time