993 resultados para Regional function


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Language is typically a function of the left hemisphere but the right hemisphere is also essential in some healthy individuals and patients. This inter-subject variability necessitates the localization of language function, at the individual level, prior to neurosurgical intervention. Such assessments are typically made by comparing left and right hemisphere language function to determine "language lateralization" using clinical tests or fMRI. Here, we show that language function needs to be assessed at the region and hemisphere specific level, because laterality measures can be misleading. Using fMRI data from 82 healthy participants, we investigated the degree to which activation for a semantic word matching task was lateralized in 50 different brain regions and across the entire cortex. This revealed two novel findings. First, the degree to which language is lateralized across brain regions and between subjects was primarily driven by differences in right hemisphere activation rather than differences in left hemisphere activation. Second, we found that healthy subjects who have relatively high left lateralization in the angular gyrus also have relatively low left lateralization in the ventral precentral gyrus. These findings illustrate spatial heterogeneity in language lateralization that is lost when global laterality measures are considered. It is likely that the complex spatial variability we observed in healthy controls is more exaggerated in patients with brain damage. We therefore highlight the importance of investigating within hemisphere regional variations in fMRI activation, prior to neuro-surgical intervention, to determine how each hemisphere and each region contributes to language processing. Hum Brain Mapp, 2010. © 2010 Wiley-Liss, Inc.

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The ATP-binding cassette (ABC) family of proteins comprise a group of membrane transporters involved in the transport of a wide variety of compounds, such as xenobiotics, vitamins, lipids, amino acids, and carbohydrates. Determining their regional expression patterns along the intestinal tract will further characterize their transport functions in the gut. The mRNA expression levels of murine ABC transporters in the duodenum, jejunum, ileum, and colon were examined using the Affymetrix MuU74v2 GeneChip set. Eight ABC transporters (Abcb2, Abcb3, Abcb9, Abcc3, Abcc6, Abcd1, Abcg5, and Abcg8) displayed significant differential gene expression along the intestinal tract, as determined by two statistical models (a global error assessment model and a classic ANOVA, both with a P < 0.01). Concordance with semiquantitative real-time PCR was high. Analyzing the promoters of the differentially expressed ABC transporters did not identify common transcriptional motifs between family members or with other genes; however, the expression profile for Abcb9 was highly correlated with fibulin-1, and both genes share a common complex promoter model involving the NFkappaB, zinc binding protein factor (ZBPF), GC-box factors SP1/GC (SP1F), and early growth response factor (EGRF) transcription binding motifs. The cellular location of another of the differentially expressed ABC transporters, Abcc3, was examined by immunohistochemistry. Staining revealed that the protein is consistently expressed in the basolateral compartment of enterocytes along the anterior-posterior axis of the intestine. Furthermore, the intensity of the staining pattern is concordant with the expression profile. This agrees with previous findings in which the mRNA, protein, and transport function of Abcc3 were increased in the rat distal intestine. These data reveal regional differences in gene expression profiles along the intestinal tract and demonstrate that a complete understanding of intestinal ABC transporter function can only be achieved by examining the physiologically distinct regions of the gut.

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BACKGROUND: Although arrhythmogenic right ventricular dysplasia (ARVD) predominantly affects the right ventricle (RV), genetic/molecular and histological changes are biventricular. Regional left ventricular (LV) function has not been systematically studied in ARVD. METHODS AND RESULTS: The study population included 21 patients with suspected ARVD who underwent evaluation with MRI including tagging. Eleven healthy volunteers served as control subjects. Peak systolic regional circumferential strain (Ecc, %) was calculated by harmonic phase from tagged MRI based on the 16-segment model. Patients who met ARVD Task Force criteria were classified as definite ARVD, whereas patients with a positive family history who had 1 additional minor criterion and patients without a family history with 1 major or 2 minor criteria were classified as probable ARVD. Of the 21 ARVD subjects, 11 had definite ARVD and 10 had probable ARVD. Compared with control subjects, probable ARVD patients had similar RV ejection fraction (58.9+/-6.2% versus 53.5+/-7.6%, P=0.20), but definite ARVD patients had significantly reduced RV ejection fraction (58.9+/-6.2% versus 45.2+/-6.0%, P=0.001). LV ejection fraction was similar in all 3 groups. Compared with control subjects, peak systolic Ecc was significantly less negative in 6 of 16 (37.5%) segments in definite ARVD and 3 of 16 segments (18.7%) in probable ARVD (all P<0.05). CONCLUSIONS: ARVD is associated with regional LV dysfunction, which appears to parallel degree of RV dysfunction. Further large studies are needed to validate this finding and to better define implications of subclinical segmental LV dysfunction.

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Trabajos recientes han puesto de manifiesto que la búsqueda española en economía realizada durante la década de los noventa ha incrementado su presencia internacional al mismo tiempo que se observa una dualidad a la difusión de la búsqueda a través de revistas nacionales e internacionales en función del ámbito de búsqueda considerado. Este trabajo analiza, a partir de la aplicación de técnicas bibliométricas que ha sido la evolución de la búsqueda regional y urbana realizada en España dentro del contexto internacional y si hay diferencias muy marcadas entre la búsqueda publicada a revistas nacionales y la publicada a revistas internacionales durante el periodo 1991-2000. Los resultados obtenidos muestran que la tendencia observada por el conjunto de la economía también se han producido (incluso con más intensidad) dentro del ámbito de la búsqueda centrada en aspectos regionales y urbanos

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Trabajos recientes han puesto de manifiesto que la búsqueda española en economía realizada durante la década de los noventa ha incrementado su presencia internacional al mismo tiempo que se observa una dualidad a la difusión de la búsqueda a través de revistas nacionales e internacionales en función del ámbito de búsqueda considerado. Este trabajo analiza, a partir de la aplicación de técnicas bibliométricas que ha sido la evolución de la búsqueda regional y urbana realizada en España dentro del contexto internacional y si hay diferencias muy marcadas entre la búsqueda publicada a revistas nacionales y la publicada a revistas internacionales durante el periodo 1991-2000. Los resultados obtenidos muestran que la tendencia observada por el conjunto de la economía también se han producido (incluso con más intensidad) dentro del ámbito de la búsqueda centrada en aspectos regionales y urbanos

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The complex regional pain syndrome (CRPS) is a rare but debilitating pain disorder that mostly occurs after injuries to the upper limb. A number of studies indicated altered brain function in CRPS, whereas possible influences on brain structure remain poorly investigated. We acquired structural magnetic resonance imaging data from CRPS type I patients and applied voxel-by-voxel statistics to compare white and gray matter brain segments of CRPS patients with matched controls. Patients and controls were statistically compared in two different ways: First, we applied a 2-sample ttest to compare whole brain white and gray matter structure between patients and controls. Second, we aimed to assess structural alterations specifically of the primary somatosensory (S1) and motor cortex (M1) contralateral to the CRPS affected side. To this end, MRI scans of patients with left-sided CRPS (and matched controls) were horizontally flipped before preprocessing and region-of-interest-based group comparison. The unpaired ttest of the "non-flipped" data revealed that CRPS patients presented increased gray matter density in the dorsomedial prefrontal cortex. The same test applied to the "flipped" data showed further increases in gray matter density, not in the S1, but in the M1 contralateral to the CRPS-affected limb which were inversely related to decreased white matter density of the internal capsule within the ipsilateral brain hemisphere. The gray-white matter interaction between motor cortex and internal capsule suggests compensatory mechanisms within the central motor system possibly due to motor dysfunction. Altered gray matter structure in dorsomedial prefrontal cortex may occur in response to emotional processes such as pain-related suffering or elevated analgesic top-down control.

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The reelin gene encodes an extracellular protein that is crucial for neuronal migration in laminated brain regions. To gain insights into the functions of Reelin, we performed high-resolution in situ hybridization analyses to determine the pattern of reelin expression in the developing forebrain of the mouse. We also performed double-labeling studies with several markers, including calcium-binding proteins, GAD65/67, and neuropeptides, to characterize the neuronal subsets that express reelin transcripts. reelinexpression was detected at embryonic day 10 and later in the forebrain, with a distribution that is consistent with the prosomeric model of forebrain regionalization. In the diencephalon, expression was restricted to transverse and longitudinal domains that delineated boundaries between neuromeres. During embryogenesis,reelin was detected in the cerebral cortex in Cajal-Retzius cells but not in the GABAergic neurons of layer I. At prenatal stages, reelin was also expressed in the olfactory bulb, and striatum and in restricted nuclei in the ventral telencephalon, hypothalamus, thalamus, and pretectum. At postnatal stages, reelin transcripts gradually disappeared from Cajal-Retzius cells, at the same time as they appeared in subsets of GABAergic neurons distributed throughout neocortical and hippocampal layers. In other telencephalic and diencephalic regions,reelin expression decreased steadily during the postnatal period. In the adult, there was prominent expression in the olfactory bulb and cerebral cortex, where it was restricted to subsets of GABAergic interneurons that co-expressed calbindin, calretinin, neuropeptide Y, and somatostatin. This complex pattern of cellular and regional expression is consistent with Reelin having multiple roles in brain development and adult brain function.

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Significant progress has been made with regard to the quantitative integration of geophysical and hydrological data at the local scale. However, extending the corresponding approaches to the regional scale represents a major, and as-of-yet largely unresolved, challenge. To address this problem, we have developed a downscaling procedure based on a non-linear Bayesian sequential simulation approach. The basic objective of this algorithm is to estimate the value of the sparsely sampled hydraulic conductivity at non-sampled locations based on its relation to the electrical conductivity, which is available throughout the model space. The in situ relationship between the hydraulic and electrical conductivities is described through a non-parametric multivariate kernel density function. This method is then applied to the stochastic integration of low-resolution, re- gional-scale electrical resistivity tomography (ERT) data in combination with high-resolution, local-scale downhole measurements of the hydraulic and electrical conductivities. Finally, the overall viability of this downscaling approach is tested and verified by performing and comparing flow and transport simulation through the original and the downscaled hydraulic conductivity fields. Our results indicate that the proposed procedure does indeed allow for obtaining remarkably faithful estimates of the regional-scale hydraulic conductivity structure and correspondingly reliable predictions of the transport characteristics over relatively long distances.

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The purpose of this article is to offer a practical approach to the new European dimension for regional parliaments signified by the entry into force of the Treaty of Lisbon. The parliamentary scrutiny of subsidiarity by way of the early warning system has assigned a new mission to legislative assemblies with the aim of reinforcing the intervention of regions in the drafting of policies by Union institutions. In the Spanish case, the institutionalisation of this mechanism came about with Act nº 24/2009, which attributes to the Joint Committee for the European Union, in the name of the Cortes Generales [the Spanish Parliament], the function of receiving the proposals for legislative acts by the EU and transferring them to the regional parliaments in order for the latter to issue, in a brief period of four weeks, a report on compliance with the principle of subsidiarity. The majority of regional parliaments have also carried out normative reforms to regulate the procedure of participation in the early warning system.

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5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) is a natural hallucinogen component of Ayahuasca, an Amazonian beverage traditionally used for ritual, religious and healing purposes that is being increasingly used for recreational purposes in US and Europe. 5MeO-DMT is of potential interest for schizophrenia research owing to its hallucinogenic properties. Two other psychotomimetic agents, phencyclidine and 2,5-dimethoxy-4-iodo-phenylisopropylamine (DOI), markedly disrupt neuronal activity and reduce the power of low frequency cortical oscillations (<4 Hz, LFCO) in rodent medial prefrontal cortex (mPFC). Here we examined the effect of 5-MeO-DMT on cortical function and its potential reversal by antipsychotic drugs. Moreover, regional brain activity was assessed by blood-oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI). 5-MeO-DMT disrupted mPFC activity, increasing and decreasing the discharge of 51 and 35% of the recorded pyramidal neurons, and reducing (−31%) the power of LFCO. The latter effect depended on 5-HT1A and 5-HT2A receptor activation and was reversed by haloperidol, clozapine, risperidone, and the mGlu2/3 agonist LY379268. Likewise, 5-MeO-DMT decreased BOLD responses in visual cortex (V1) and mPFC. The disruption of cortical activity induced by 5-MeO-DMT resembles that produced by phencyclidine and DOI. This, together with the reversal by antipsychotic drugs, suggests that the observed cortical alterations are related to the psychotomimetic action of 5-MeO-DMT. Overall, the present model may help to understand the neurobiological basis of hallucinations and to identify new targets in antipsychotic drug development.

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The identification of biomarkers of vascular cognitive impairment is urgent for its early diagnosis. The aim of this study was to detect and monitor changes in brain structure and connectivity, and to correlate them with the decline in executive function. We examined the feasibility of early diagnostic magnetic resonance imaging (MRI) to predict cognitive impairment before onset in an animal model of chronic hypertension: Spontaneously Hypertensive Rats. Cognitive performance was tested in an operant conditioning paradigm that evaluated learning, memory, and behavioral flexibility skills. Behavioral tests were coupled with longitudinal diffusion weighted imaging acquired with 126 diffusion gradient directions and 0.3 mm(3) isometric resolution at 10, 14, 18, 22, 26, and 40 weeks after birth. Diffusion weighted imaging was analyzed in two different ways, by regional characterization of diffusion tensor imaging (DTI) indices, and by assessing changes in structural brain network organization based on Q-Ball tractography. Already at the first evaluated times, DTI scalar maps revealed significant differences in many regions, suggesting loss of integrity in white and gray matter of spontaneously hypertensive rats when compared to normotensive control rats. In addition, graph theory analysis of the structural brain network demonstrated a significant decrease of hierarchical modularity, global and local efficacy, with predictive value as shown by regional three-fold cross validation study. Moreover, these decreases were significantly correlated with the behavioral performance deficits observed at subsequent time points, suggesting that the diffusion weighted imaging and connectivity studies can unravel neuroimaging alterations even overt signs of cognitive impairment become apparent.

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This thesis consists of a quantitative analysis of the regional prevalence of certain artistic motifs as they appear in Minoan wall painting of the Neopalatial period. This will help to establish the relative degree of artistic autonomy exercised by each of the sites included in this study. The results show that the argument for itinerant artists during this time period is a strong one, but the assumption that these travelling artists were being controlled by any one palace-centre is erroneous. Rather, the similarities and differences seen suggest that the choices were predicated either by the specific patrons, or by the function of the associated building or room. Thus, the motifs found within this study should be understood as constituting a cultural identity, with greater or lesser degrees of regional homogeneity, which act as one facet of a number of cultural indicators that can be used to better understand the role of artists and regional dynamics on the island during the Bronze Age.

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Land use is a crucial link between human activities and the natural environment and one of the main driving forces of global environmental change. Large parts of the terrestrial land surface are used for agriculture, forestry, settlements and infrastructure. Given the importance of land use, it is essential to understand the multitude of influential factors and resulting land use patterns. An essential methodology to study and quantify such interactions is provided by the adoption of land-use models. By the application of land-use models, it is possible to analyze the complex structure of linkages and feedbacks and to also determine the relevance of driving forces. Modeling land use and land use changes has a long-term tradition. In particular on the regional scale, a variety of models for different regions and research questions has been created. Modeling capabilities grow with steady advances in computer technology, which on the one hand are driven by increasing computing power on the other hand by new methods in software development, e.g. object- and component-oriented architectures. In this thesis, SITE (Simulation of Terrestrial Environments), a novel framework for integrated regional sland-use modeling, will be introduced and discussed. Particular features of SITE are the notably extended capability to integrate models and the strict separation of application and implementation. These features enable efficient development, test and usage of integrated land-use models. On its system side, SITE provides generic data structures (grid, grid cells, attributes etc.) and takes over the responsibility for their administration. By means of a scripting language (Python) that has been extended by language features specific for land-use modeling, these data structures can be utilized and manipulated by modeling applications. The scripting language interpreter is embedded in SITE. The integration of sub models can be achieved via the scripting language or by usage of a generic interface provided by SITE. Furthermore, functionalities important for land-use modeling like model calibration, model tests and analysis support of simulation results have been integrated into the generic framework. During the implementation of SITE, specific emphasis was laid on expandability, maintainability and usability. Along with the modeling framework a land use model for the analysis of the stability of tropical rainforest margins was developed in the context of the collaborative research project STORMA (SFB 552). In a research area in Central Sulawesi, Indonesia, socio-environmental impacts of land-use changes were examined. SITE was used to simulate land-use dynamics in the historical period of 1981 to 2002. Analogous to that, a scenario that did not consider migration in the population dynamics, was analyzed. For the calculation of crop yields and trace gas emissions, the DAYCENT agro-ecosystem model was integrated. In this case study, it could be shown that land-use changes in the Indonesian research area could mainly be characterized by the expansion of agricultural areas at the expense of natural forest. For this reason, the situation had to be interpreted as unsustainable even though increased agricultural use implied economic improvements and higher farmers' incomes. Due to the importance of model calibration, it was explicitly addressed in the SITE architecture through the introduction of a specific component. The calibration functionality can be used by all SITE applications and enables largely automated model calibration. Calibration in SITE is understood as a process that finds an optimal or at least adequate solution for a set of arbitrarily selectable model parameters with respect to an objective function. In SITE, an objective function typically is a map comparison algorithm capable of comparing a simulation result to a reference map. Several map optimization and map comparison methodologies are available and can be combined. The STORMA land-use model was calibrated using a genetic algorithm for optimization and the figure of merit map comparison measure as objective function. The time period for the calibration ranged from 1981 to 2002. For this period, respective reference land-use maps were compiled. It could be shown, that an efficient automated model calibration with SITE is possible. Nevertheless, the selection of the calibration parameters required detailed knowledge about the underlying land-use model and cannot be automated. In another case study decreases in crop yields and resulting losses in income from coffee cultivation were analyzed and quantified under the assumption of four different deforestation scenarios. For this task, an empirical model, describing the dependence of bee pollination and resulting coffee fruit set from the distance to the closest natural forest, was integrated. Land-use simulations showed, that depending on the magnitude and location of ongoing forest conversion, pollination services are expected to decline continuously. This results in a reduction of coffee yields of up to 18% and a loss of net revenues per hectare of up to 14%. However, the study also showed that ecological and economic values can be preserved if patches of natural vegetation are conservated in the agricultural landscape. -----------------------------------------------------------------------

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Se ha dicho que el Desarrollo Regional Endógeno implica el cambio social sostenido que lleve al perfeccionamiento de una región. Para que se dé ese cambio, es necesario partir de la activación de las capacidades internas lo que implícitamente incluye la organización del territorio. Dicha organización para el caso de Boyacá es la Provincia o Provincias. Y lo es debido a que la provincia como unidad territorial es un lugar concreto de la acción política, donde es factible organizar la sociedad y donde se pueden coordinar sus necesidades por medio de la participación. Lo es también, ya que la provincia es resultado de los usos del territorio a través del tiempo, no es un capricho ni es resultado del azar o de los intereses de algunos, es pues unidad histórica. Y lo es, porque implica reconocer que la disposición del territorio con miras a una función y usos determinados, unidad funcional, es definitiva en la capacidad territorial de toma de decisión, en la elección, el diseño, la ejecución y la evaluación de políticas; es decir, en el proceso de Gestión Pública que involucra la Planificación y que se alimenta asimismo de ella. La provincia es la unidad territorial (lugar concreto de acción) histórico (trascendente) funcional (que se emplea) para la Planificación en la Gestión del Desarrollo Regional Endógeno en Boyacá.

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El autor aborda en este artículo cuestiones atinentes al espacio, la geografía y la organización del territorio a partir del tema del desarrollo. Para fundamentar su tesis según la cual varios de los factores que impulsan la globalización tienen una base territorial, como el comercio internacional de bienes y servicios, el cambio tecnológico o los flujos internacionales, apela a las categorías del desarrollo social y las sitúa en dos dimensiones. En una primera instancia, el autor toma en cuenta la lógica intranacional de despliegue de los factores políticos, ambientales y comerciales; en un segundo momento destaca el papel de las regiones y las localidades en la reconstrucción del sistema económico mundial para concluir que en un contexto todavía incierto se destaca la configuración de regiones megapolitanas que funcionan como motores regionales en la nueva economía global.---The author handles this article with questions that regard space,geography and territorial organisation based on the topic of development. To support his thesis that refers to the way in which various factors that give an impulse to globalisation have a territorial base, such as the international commerce of goods and services, technological change or international networks, the author utilises social development categories and places them in two dimensions. Initially, the author takes into account the international logic of the development of commercial, environment and political factors. Secondly, he emphasizes the role of regions and localities in the reconstruction of the global economic system to conclude that in a present uncertain context it is worth pointing out the configuration of megapolitanregions that function as regional motors in a new global economy.