971 resultados para Hemispheric specialization
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Dorsal and ventral pathways for syntacto-semantic speech processing in the left hemisphere are represented in the dual-stream model of auditory processing. Here we report new findings for the right dorsal and ventral temporo-frontal pathway during processing of affectively intonated speech (i.e. affective prosody) in humans, together with several left hemispheric structural connections, partly resembling those for syntacto-semantic speech processing. We investigated white matter fiber connectivity between regions responding to affective prosody in several subregions of the bilateral superior temporal cortex (secondary and higher-level auditory cortex) and of the inferior frontal cortex (anterior and posterior inferior frontal gyrus). The fiber connectivity was investigated by using probabilistic diffusion tensor based tractography. The results underscore several so far underestimated auditory pathway connections, especially for the processing of affective prosody, such as a right ventral auditory pathway. The results also suggest the existence of a dual-stream processing in the right hemisphere, and a general predominance of the dorsal pathways in both hemispheres underlying the neural processing of affective prosody in an extended temporo-frontal network.
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We study relative price behavior in an international business cyclemodel with specialization in production, in which a goods marketfriction is introduced through transport costs. The transporttechnology allows for flexible transport costs. We analyze whetherthis extension can account for the striking differences betweentheory and data as far as the moments of terms of trade and realexchange rates are concerned. We find that transport costs increaseboth the volatility of the terms of trade and the volatility of thereal exchange rate. However, unless the transport technology isspecified by a Leontief technology, transport costs do not resolvethe quantitative discrepancies between theory and data. Asurprising result is that transport costs may actually lower thepersistence of the real exchange rate, a finding that is in contrastto much of the emphasis of the empirical literature.
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Studies aiming at explaining specialization along latitudinal gradients of plant-herbivore interactions have, to date, yielded inconclusive results. Here we propose the use of steep altitudinal gradients for dissecting factors driving evolution of polyphagy in insect herbivores. First, we test whether colonization of high elevation environment favours increased niche-breadth in two disparate insect groups - the wood-boring beetles and the pollinator group of bees - and show increased polyphagy at higher altitudes in both groups. We then assess classic assumptions transferred from the 'latitude-niche-breadth hypothesis', particularly the increase in environmental variability at high, compared to low, altitude. Finally, we discuss alternative mechanisms shaping the observed pattern of increased polyphagy in altitude, including variation in plant quality and predator pressure at different altitudes. We thus suggest evidence for the 'altitude niche-breadth hypothesis', in which both abiotic and biotic conditions, including increased variability and an increase of the potential feeding niche-breadth, promote evolution for increased insect polyphagy in altitude.
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O presente Relatório de Estágio insere-se no âmbito da Unidade Curricular de Estágio, realizado na empresa MundiServiços, Consultoria de Gestão e Formação, Sucursal de Cabo Verde, conducente ao grau de Mestre em Ciências da Educação com especialização na área de Formação de Adultos. A Sucursal da MundiServiços em Cabo Verde centra a sua intervenção no mercado cabo-verdiano essencialmente em dois eixos: Consultoria na área de Gestão de Recursos Humanos e Formação Profissional. O meu Projecto de Estágio tem a sua incidência na área da Formação Profissional e visa responder a uma solicitação da ARFA - Agência de Regulação e Supervisão de Produtos Farmacêuticos e Alimentares - organização cliente da MundiServiços em Cabo Verde. Neste contexto, o Projecto de Estágio tem como finalidade a realização de um Estudo de Diagnóstico de Necessidades de Formação e a Elaboração de um Plano Estratégico de Formação que possa satisfazer as necessidades organizacionais, profissionais e pessoais da Agência e dos seus trabalhadores. Este trabalho enquadra-se numa medida estratégica da entidade, que passa pelo desenvolvimento de competências chave dos seus recursos humanos, como forma de responder a novos desafios estratégicos e organizacionais e de aumentar a motivação e satisfação interna dos seus trabalhadores. De acordo com os objectivos pré-estabelecidos para a execução deste estudo, tentou-se combinar as metodologias qualitativa e quantitativa, com recurso a diferentes técnicas de recolha, análise e tratamento de dados, com a principal finalidade de obter informações que permitam responder, de forma efectiva, à solicitação da agência, transformando as necessidades formativas dos trabalhadores em potencialidades.
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In this paper, we incorporate a positive theory of unemployment insuranceinto a dynamic overlapping generations model with search-matching frictionsand on-the-job learning-by-doing. The model shows that societies populatedby identical rational agents, but differing in the initial distributionof human capital across agents, may choose very different unemploymentinsurance levels in a politico-economic equilibrium. The interactionbetween the political decision about the level of the unemployment insuranceand the optimal search behavior of the unemployed gives rise to aself-reinforcing mechanism whichmay generate multiple steady-stateequilibria. In particular, a European-type steady-state with highunemployment, low employment turnover and high insurance can co-exist withan American-type steady-state with low unemployment, high employment turnoverand low unemployment insurance. A calibrated version of the model featurestwo distinct steady-state equilibria with unemployment levels and durationrates resembling those of the U.S. and Europe, respectively.
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Bees and angiosperms established a mutualistic relationship along the evolutionary time. The aim of this study is to contribute for the understanding of this relation analyzing pollen stored by stingless bees colonies distributed along the Rio Negro. Fourteen species of Meliponini from the genera Partamona, Scaura, and Trigona were studied with regard to the content of pollen pots. The pollen material was removed from the pollen pots, homogenized, and prepared according to the usual acetolysis technique. The overlap of the trophic niche and the grouping of species by similarity of niches was calculated. The identification revealed 78 pollen types belonging to 36 families, being 37 types attractive and 16 considered as promoters of a temporary specialization event. With the results, it was possible to indicate a list of important plants for meliponiculture in the Amazon.
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In recent years, Spain has received unprecedented immigration flows. Between 2001 and 2006 the fraction of the population born abroad more than doubled, increasing from4.8% to 10.8%. For Spanish provinces with above-median inflows (relative to population),immigration increased by 24% the number of high school dropouts while only increasingcollege graduates by 11%. We study different channels by which regional labor markets haveabsorbed the large increase in relative supply of low educated workers. We identify theexogenous supply shock using historical immigrant settlement patterns by country of origin.Using data from the Labor Force Survey and the decennial Census, we find a large expansion ofemployment in high immigration regions. Disaggregating by industry, the absorption operatedthrough large increases in the share of low-educated workers, compared to the same industry inlow-immigration regions. We do not find changes in sectoral specialization. Overall, andperhaps surprisingly, the pattern of absorption is very similar to the one found in the US.
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This article investigates the main sources of heterogeneity in regional efficiency. We estimate a translog stochastic frontier production function in the analysis of Spanish regions in the period 1964-1996, to attempt to measure and explain changes in technical efficiency. Our results confirm that regional inefficiency is significantly and positively correlated with the ratio of public capital to private capital. The proportion of service industries in the private capital, the proportion of public capital devoted to transport infrastructures, the industrial specialization, and spatial spillovers from transport infrastructures in neighbouring regions significantly contributed to improve regional efficiency.
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This essay reviews some findings in cognition sciences and examines their consequences for the analysis of institutions. It starts by exploring how humans specialization in producing knowledge ensures our success in dominating the environment but also changes fast our environment. So fast that it did not give time to natural selection to adapt our biology, causing it to be potentially maladapted in important dimensions. A main function of institutions is therefore to fill the gap between the demands of our relatively new environment and our biology, still adapted to our ancestral environment as hunter-gatherers. Moreover, institutions are built with the available elements, which include our instincts. A deeper understanding of both aspects, their adaptive function and this recruitment of ancestral instincts, will add greatly to our ability to manage institutions.
Identification of optimal structural connectivity using functional connectivity and neural modeling.
Resumo:
The complex network dynamics that arise from the interaction of the brain's structural and functional architectures give rise to mental function. Theoretical models demonstrate that the structure-function relation is maximal when the global network dynamics operate at a critical point of state transition. In the present work, we used a dynamic mean-field neural model to fit empirical structural connectivity (SC) and functional connectivity (FC) data acquired in humans and macaques and developed a new iterative-fitting algorithm to optimize the SC matrix based on the FC matrix. A dramatic improvement of the fitting of the matrices was obtained with the addition of a small number of anatomical links, particularly cross-hemispheric connections, and reweighting of existing connections. We suggest that the notion of a critical working point, where the structure-function interplay is maximal, may provide a new way to link behavior and cognition, and a new perspective to understand recovery of function in clinical conditions.
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Disentangling the mechanisms mediating the coexistence of habitat specialists and generalists has been a long-standing subject of investigation. However, the roles of species traits and environmental and spatial factors have not been assessed in a unifying theoretical framework. Theory suggests that specialist species are more competitive in natural communities. However, empirical work has shown that specialist species are declining worldwide due to habitat loss and fragmentation. We addressed the question of the coexistence of specialist and generalist species with a spatially explicit metacommunity model in continuous and heterogeneous environments. We characterized how species' dispersal abilities, the number of interacting species, environmental spatial autocorrelation, and disturbance impact community composition. Our results demonstrated that species' dispersal ability and the number of interacting species had a drastic influence on the composition of metacommunities. More specialized species coexisted when species had large dispersal abilities and when the number of interacting species was high. Disturbance selected against highly specialized species, whereas environmental spatial autocorrelation had a marginal impact. Interestingly, species richness and niche breadth were mainly positively correlated at the community scale but were negatively correlated at the metacommunity scale. Numerous diversely specialized species can thus coexist, but both species' intrinsic traits and environmental factors interact to shape the specialization signatures of communities at both the local and global scales.
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The interhemispheric asymmetries that originate from connectivity-related structuring of the cortex are compromised in schizophrenia (SZ). Under the assumption that such abnormalities affect functional connectivity, we analyzed its correlate-EEG synchronization-in SZ patients and matched controls. We applied multivariate synchronization measures based on Laplacian EEG and tuned to various spatial scales. Compared to the controls who had rightward asymmetry at a local level (EEG power), rightward anterior and leftward posterior asymmetries at an intraregional level (1st and 2nd order S-estimator), and rightward global asymmetry (hemispheric S-estimator), SZ patients showed generally attenuated asymmetry, the effect being strongest for intraregional synchronization in the alpha and beta bands. The abnormalities of asymmetry increased with the duration of the disease and correlated with the negative symptoms. We discuss the tentative links between these findings and gross anatomical asymmetries, including the cerebral torque and gyrification pattern, in normal subjects and SZ patients.
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The glyoxalase system is the most important pathway for the detoxification of methylglyoxal (MG), a highly reactive dicarbonyl compound mainly formed as a by-product of glycolysis. MG is a major precursor of advanced glycation end products (AGEs), which are associated with several neurodegenerative disorders. Although the neurotoxic effects of MG and AGEs are well characterized, little is known about the glyoxalase system in the brain, in particular with regards to its activity in different neural cell types. Results of the present study reveal that both enzymes composing the glyoxalase system [glyoxalase-1 (Glo-1) and Glo-2] were highly expressed in primary mouse astrocytes compared with neurons, which translated into higher enzymatic activity rates in astrocytes (9.9- and 2.5-fold, respectively). The presence of a highly efficient glyoxalase system in astrocytes was associated with lower accumulation of AGEs compared with neurons (as assessed by Western blotting), a sixfold greater resistance to MG toxicity, and the capacity to protect neurons against MG in a coculture system. In addition, Glo-1 downregulation using RNA interference strategies resulted in a loss of viability in neurons, but not in astrocytes. Finally, stimulation of neuronal glycolysis via lentiviral-mediated overexpression of 6-phosphofructose-2-kinase/fructose-2,6-bisphosphatase-3 resulted in increased MG levels and MG-modified proteins. Since MG is largely produced through glycolysis, this suggests that the poor capacity of neurons to upregulate their glycolytic flux as compared with astrocytes may be related to weaker defense mechanisms against MG toxicity. Accordingly, the neuroenergetic specialization taking place between these two cell types may serve as a protective mechanism against MG-induced neurotoxicity.
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Food products are a specialization, an industry of excellence, and thelargest sector of manufacturing employment in the state of Iowa. All ofthe top five food companies have operations in Iowa. According to Harris Info Source, manufacturing of foods and ingredients in Iowa employs 58,826 people at 775 plants. Processing and value adding enterprises are fed by nation-leading agriculture. Iowa is the top producer of corn, soybeans, hogs and eggs in the United States.