996 resultados para Spatial perception
Resumo:
BACKGROUND: Radial maze tasks have been used to assess optimal foraging and spatial abilities in rodents. The spatial performance was based on a capacity to rely on a configuration of local and distant cues. We adapted maze procedures assessing the relative weight of local cues and distant landmarks for arm choice in humans. NEW METHOD: The procedure allowed testing memory of places in four experimental setups: a fingertip texture-groove maze, a tactile screen maze, a virtual radial maze and a walking size maze. During training, the four reinforced positions remained fixed relative to local and distal cues. During subsequent conflict trials, these frameworks were made conflictive in the prediction of reward locations. RESULTS: Three experiments showed that the relative weight of local and distal relational cues is affected by different factors such as cues' nature, visual access to the environment, real vs. virtual environment, and gender. A fourth experiment illustrated how a walking maze can be used with people suffering intellectual disability. COMPARISON WITH EXISTING METHODS: In our procedure, long-term (reference) and short-term (working) memory can be assessed. It is the first radial task adapted to human that enables dissociating local and distal cues, to provides an indication as to their relative salience. Our mazes are moveable and easily used in limited spaces. Tasks are performed with realistic and spontaneous though controlled exploratory movements. CONCLUSION: Our tasks enabled highlighting the use of different strategies. In a clinical perspective, considering the use of compensatory strategies should orient towards adapted behavioural rehabilitation.
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Biotic interactions are known to affect the composition of species assemblages via several mechanisms, such as competition and facilitation. However, most spatial models of species richness do not explicitly consider inter-specific interactions. Here, we test whether incorporating biotic interactions into high-resolution models alters predictions of species richness as hypothesised. We included key biotic variables (cover of three dominant arctic-alpine plant species) into two methodologically divergent species richness modelling frameworks - stacked species distribution models (SSDM) and macroecological models (MEM) - for three ecologically and evolutionary distinct taxonomic groups (vascular plants, bryophytes and lichens). Predictions from models including biotic interactions were compared to the predictions of models based on climatic and abiotic data only. Including plant-plant interactions consistently and significantly lowered bias in species richness predictions and increased predictive power for independent evaluation data when compared to the conventional climatic and abiotic data based models. Improvements in predictions were constant irrespective of the modelling framework or taxonomic group used. The global biodiversity crisis necessitates accurate predictions of how changes in biotic and abiotic conditions will potentially affect species richness patterns. Here, we demonstrate that models of the spatial distribution of species richness can be improved by incorporating biotic interactions, and thus that these key predictor factors must be accounted for in biodiversity forecasts
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Background: Although the mechanisms are not well understood yet, evidence exists of the benefits of urban green spaces for human health. As a consequence, one of the concerns of public health interventions must be to promote the use of urban green spaces within cities. Aims: This study aims to explore the citizens’ purposes of use of urban green spaces as well as the elements related to the characteristics of these places that condition their use. Methods: In-depth interviews were conducted with non-hospitalised people living in different areas of Barcelona, with different socioeconomic status and different residential distance to urban green spaces (n = 20). Thematic content analysis of the qualitative data was performed. Results: Physical pursuits and attention restoration were identified as prominent purposes of use of urban green spaces. The natural features of urban green spaces were identified as the most relevant determiners for the use of these places. Conclusions: To promote the use of urban green spaces, qualitative findings from this study suggest that purpose-built places should be provided. Moreover, natural features of urban green spaces must be particularly taken into account when designing and maintaining them.
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Using data from free listings and a survey in two villages of Tamil Nadu, India, we discuss local perceptions and uses of water tanks, a traditional irrigation infrastructure. We hypothesize that both farmers and nonfarmers perceive and use water tanks for purposes other than irrigation. We found that informants recognized the importance of water tanks for irrigation, but also acknowledged other socioeconomic uses and ecological functions. Marginal sectors (i.e., Scheduled Castes) use tank resources in more diverse ways than other sectors of the population. Findings are relevant for development. International organizations working on the revival of water tanks aim to transfer water management to farmers for the purpose of irrigation. By recognizing that tanks benefit people other than farmers and in ways other than providing irrigation water, organizations working on tank rejuvenation could achieve a more equitable management of tank resources.
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Mountain regions worldwide are particularly sensitive to on-going climate change. Specifically in the Alps in Switzerland, the temperature has increased twice as fast than in the rest of the Northern hemisphere. Water temperature closely follows the annual air temperature cycle, severely impacting streams and freshwater ecosystems. In the last 20 years, brown trout (Salmo trutta L) catch has declined by approximately 40-50% in many rivers in Switzerland. Increasing water temperature has been suggested as one of the most likely cause of this decline. Temperature has a direct effect on trout population dynamics through developmental and disease control but can also indirectly impact dynamics via food-web interactions such as resource availability. We developed a spatially explicit modelling framework that allows spatial and temporal projections of trout biomass using the Aare river catchment as a model system, in order to assess the spatial and seasonal patterns of trout biomass variation. Given that biomass has a seasonal variation depending on trout life history stage, we developed seasonal biomass variation models for three periods of the year (Autumn-Winter, Spring and Summer). Because stream water temperature is a critical parameter for brown trout development, we first calibrated a model to predict water temperature as a function of air temperature to be able to further apply climate change scenarios. We then built a model of trout biomass variation by linking water temperature to trout biomass measurements collected by electro-fishing in 21 stations from 2009 to 2011. The different modelling components of our framework had overall a good predictive ability and we could show a seasonal effect of water temperature affecting trout biomass variation. Our statistical framework uses a minimum set of input variables that make it easily transferable to other study areas or fish species but could be improved by including effects of the biotic environment and the evolution of demographical parameters over time. However, our framework still remains informative to spatially highlight where potential changes of water temperature could affect trout biomass. (C) 2015 Elsevier B.V. All rights reserved.-
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La perception du patient vis-à-vis de son médecin traitant (MT) a suscité beaucoup de recherches et d'interet, notamment à cause de l'importance de la relation médecin-patient nécessaire à la qualité des soins. En Suisse, dans un contexte de libre choix du médecin, le rôle de MT peut être assumé par un generalise mais aussi, théoriquement, par un spécialiste. La fréquence de cette situation est cependant inconnue de même que son impact sur l'expérience des patients. L'objectif principal de cette etude était de décrire l'expérience des personnes âgées du canton de Vaud auprès de leur medecin traitant et de tester l'hypothèse selon laquelle cette expérience serait différente lorsque le MT est décrit comme « Généraliste » (MT Gén) ou comme « Spécialiste » (MT Spéc). Méthode : La recherche a été effectuée sur la base des données d'une enquête par questionnaire, envoyé à la population lausannoise participant à l'étude Lc65+ et à un échantillon supplémentaire de personnes agees de 68 ans ou plus sélectionnées aléatoirement dans le canton de Vaud. L'analyse a porté sur 17 items relatifs à la perception qu'ont les patients de leur MT, regroupés en 4 thèmes ? Access,bihte/Disponibilité, Relation Médecin-Patient, Information et Continuité des soins Nous ayons également analysé le recours déclaré aux soins ambulatoires, aux consultations de services d urgence, ainsi qu'aux actes de prévention. Les différences de perception et de recours selon le type de MT (Gen vs Spéc) ont été analysées par des modèles multivariés tenant compte de l'âge du sexe de I education, de la morbidité, de la présence de symptômes dépressifs et de la durée de la relation medecin-patient. Résultats : Les participants ont exprimé une perception favorable de leur MT à des taux excédant 75% pour la plupart des 17 items. Cependant, seulement 38 à 51% des participants ont répondu positivement aux questions relatives à la disponibilité en dehors des heures d'ouvertures, à l'accès au MT le soir ou en tin de semaine, à la possibilité de visites à domicile, à la probabilité de se voir prescrire des medicaments coûteux en cas de besoin, ou à la connaissance du médecin des médicaments en vente libre que le patient consomme. Les analyses bivariées et multivariées n'ont pas montré de différence entre les groupes MT Gén et MT Spec quant à la perception qu'ont les patients de leur MT, au recours aux actes de prévention ou aux services de santé. Conclusion : L'expérience des personnes interrogées était globalement positive, à part quelques questions concernant principalement le thème de l'Accessibilité/Disponibilité du MT. Nous n'avons pas mis en evidence de différence de perception ou de recours aux soins entre les deux groupes que nous avons analyses pour tester notre hypothèse. Perspective : Cette étude connaît des limites (données rapportées par les participants, groupe des MT Spéc de taille restreinte, absence de données sur les non-répondants, possible conflit de loyauté vis-à-vis du MT pour certaines questions) mais repose sur un large échantillon lui conférant une puissance suffisante, aléatoirement sélectionné dans une population géographiquement définie. Bien que ces résultats ne soient généralisables qu'au canton de Vaud, elle montre d'abord que les spécialistes reconnus comme MT s'inscrivent généralement dans des disciplines impliquant une formation en medec.ne interne. Dans cette circonstance, elle ne met en évidence aucune différence de résultats entre les personnes âgées traitées par un MT généraliste ou spécialiste.
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Pain perception has evolved as a warning mechanism to alert organisms to tissue damage and dangerous environments. In humans, however, undesirable, excessive or chronic pain is a common and major societal burden for which available medical treatments are currently suboptimal. New therapeutic options have recently been derived from studies of individuals with congenital insensitivity to pain (CIP). Here we identified 10 different homozygous mutations in PRDM12 (encoding PRDI-BF1 and RIZ homology domain-containing protein 12) in subjects with CIP from 11 families. Prdm proteins are a family of epigenetic regulators that control neural specification and neurogenesis. We determined that Prdm12 is expressed in nociceptors and their progenitors and participates in the development of sensory neurons in Xenopus embryos. Moreover, CIP-associated mutants abrogate the histone-modifying potential associated with wild-type Prdm12. Prdm12 emerges as a key factor in the orchestration of sensory neurogenesis and may hold promise as a target for new pain therapeutics.
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Allocentric spatial memory, the memory for locations coded in relation to objects comprising our environment, is a fundamental component of episodic memory and is dependent on the integrity of the hippocampal formation in adulthood. Previous research from different laboratories reported that basic allocentric spatial memory abilities are reliably observed in children after 2 years of age. Based on work performed in monkeys and rats, we had proposed that the functional maturation of direct entorhinal cortex projections to the CA1 field of the hippocampus might underlie the emergence of basic allocentric spatial memory. We also proposed that the protracted development of the dentate gyrus and its projections to the CA3 field of the hippocampus might underlie the development of high-resolution allocentric spatial memory capacities, based on the essential contribution of these structures to the process known as pattern separation. Here, we present an experiment designed to assess the development of spatial pattern separation capacities and its impact on allocentric spatial memory performance in children from 18 to 48 months of age. We found that: (1) allocentric spatial memory performance improved with age, (2) as compared to younger children, a greater number of children older than 36 months advanced to the final stage requiring the highest degree of spatial resolution, and (3) children that failed at different stages exhibited difficulties in discriminating locations that required higher spatial resolution abilities. These results are consistent with the hypothesis that improvements in human spatial memory performance might be linked to improvements in pattern separation capacities.