794 resultados para Distributed Representations
Resumo:
Application of semi-distributed hydrological models to large, heterogeneous watersheds deals with several problems. On one hand, the spatial and temporal variability in catchment features should be adequately represented in the model parameterization, while maintaining the model complexity in an acceptable level to take advantage of state-of-the-art calibration techniques. On the other hand, model complexity enhances uncertainty in adjusted model parameter values, therefore increasing uncertainty in the water routing across the watershed. This is critical for water quality applications, where not only streamflow, but also a reliable estimation of the surface versus subsurface contributions to the runoff is needed. In this study, we show how a regularized inversion procedure combined with a multiobjective function calibration strategy successfully solves the parameterization of a complex application of a water quality-oriented hydrological model. The final value of several optimized parameters showed significant and consistentdifferences across geological and landscape features. Although the number of optimized parameters was significantly increased by the spatial and temporal discretization of adjustable parameters, the uncertainty in water routing results remained at reasonable values. In addition, a stepwise numerical analysis showed that the effects on calibration performance due to inclusion of different data types in the objective function could be inextricably linked. Thus caution should be taken when adding or removing data from an aggregated objective function.
Resumo:
Dans le domaine de la perception, l'apprentissage est contraint par la présence d'une architecture fonctionnelle constituée d'aires corticales distribuées et très spécialisées. Dans le domaine des troubles visuels d'origine cérébrale, l'apprentissage d'un patient hémi-anopsique ou agnosique sera limité par ses capacités perceptives résiduelles, mais un déficit de reconnaissance visuelle de nature apparemment perceptive, peut également être associé à une altération des représentations en mémoire à long terme. Des réseaux neuronaux distincts pour la reconnaissance - cortex temporal - et pour la localisation des sons - cortex pariétal - ont été décrits chez l'homme. L'étude de patients cérébro-lésés confirme le rôle des indices spatiaux dans un traitement auditif explicite du « where » et dans la discrimination implicite du « what ». Cette organisation, similaire à ce qui a été décrit dans la modalité visuelle, faciliterait les apprentissages perceptifs. Plus généralement, l'apprentissage implicite fonde une grande partie de nos connaissances sur le monde en nous rendant sensible, à notre insu, aux règles et régularités de notre environnement. Il serait impliqué dans le développement cognitif, la formation des réactions émotionnelles ou encore l'apprentissage par le jeune enfant de sa langue maternelle. Le caractère inconscient de cet apprentissage est confirmé par l'étude des temps de réaction sériels de patients amnésiques dans l'acquisition d'une grammaire artificielle. Son évaluation pourrait être déterminante dans la prise en charge ré-adaptative. [In the field of perception, learning is formed by a distributed functional architecture of very specialized cortical areas. For example, capacities of learning in patients with visual deficits - hemianopia or visual agnosia - from cerebral lesions are limited by perceptual abilities. Moreover a visual deficit in link with abnormal perception may be associated with an alteration of representations in long term (semantic) memory. Furthermore, perception and memory traces rely on parallel processing. This has been recently demonstrated for human audition. Activation studies in normal subjects and psychophysical investigations in patients with focal hemispheric lesions have shown that auditory information relevant to sound recognition and that relevant to sound localisation are processed in parallel, anatomically distinct cortical networks, often referred to as the "What" and "Where" processing streams. Parallel processing may appear counterintuitive from the point of view of a unified perception of the auditory world, but there are advantages, such as rapidity of processing within a single stream, its adaptability in perceptual learning or facility of multisensory interactions. More generally, implicit learning mechanisms are responsible for the non-conscious acquisition of a great part of our knowledge about the world, using our sensitivity to the rules and regularities structuring our environment. Implicit learning is involved in cognitive development, in the generation of emotional processing and in the acquisition of natural language. Preserved implicit learning abilities have been shown in amnesic patients with paradigms like serial reaction time and artificial grammar learning tasks, confirming that implicit learning mechanisms are not sustained by the cognitive processes and the brain structures that are damaged in amnesia. In a clinical perspective, the assessment of implicit learning abilities in amnesic patients could be critical for building adapted neuropsychological rehabilitation programs.]
Resumo:
Abstract Island biogeography has provided fundamental hypotheses in population genetics, ecology and evolutionary biology. Insular populations usually face different feeding conditions, predation pressure, intraspecific and interspecific competition than continental populations. This so-called island syndrome can promote the evolution of specific phenotypes like a small (or large) body size and a light (or dark) colouration as well as influence the evolution of sexual dimorphism. To examine whether insularity leads to phenotypic differentiation in a consistent way in a worldwide-distributed nonmigratory species, we compared body size, body shape and colouration between insular and continental barn owl (Tyto alba) populations by controlling indirectly for phylogeny. This species is suitable because it varies in pheomelanin-based colouration from reddish-brown to white, and it displays eumelanic black spots for which the number and size vary between individuals, populations and species. Females are on average darker pheomelanic and display more and larger eumelanic spots than males. Our results show that on islands barn owls exhibited smaller and fewer eumelanic spots and lighter pheomelanic colouration, and shorter wings than on continents. Sexual dimorphism in pheomelanin-based colouration was less pronounced on islands than continents (i.e. on islands males tended to be as pheomelanic as females), and on small islands owls were redder pheomelanic and smaller in size than owls living on larger islands. Sexual dimorphism in the size of eumelanic spots was more pronounced (i.e. females displayed much larger spots than males) in barn owls living on islands located further away from a continent. Our study indicates that insular conditions drive the evolution towards a lower degree of eumelanism, smaller body size and affects the evolution of sexual dichromatism in melanin-based colour traits. The effect of insularity was more pronounced on body size and shape than on melanic traits.
Resumo:
La venue au monde d'un enfant avec une fente faciale constitue un événement stressant, voire traumatique, pour les parents. Que ce soit à travers le risque de symptômes associés, la logistique d'alimentation ou par simples raisons d'esthétisme, de nombreuses personnes vivent l'annonce de la présence d'une fente faciale comme une intrusion brutale dans le vécu de la grossesse et une interruption momentanée de l'investissement représentationnel du foetus. À travers notre recherche, nous montrons qu'un haut stress n'influe pas forcément négativement sur le développement de la relation entre le parent et l'enfant et que, au contraire, dans le cas des pères, il peut contribuer à l'implication émotionnelle envers le bébé. Le moment de l'annonce de la malformation a aussi une importance dans les représentations à propos de l'enfant puisque si elle est faite durant la période prénatale, elle permet aux parents un réarrangement des représentations afin de mieux accueillir le bébé le jour de sa naissance. The birth of a child with a facial cleft is often seen as a very stressing event for both parents. Risks of comorbidity, difficulty in nutrition or just aesthetical reasons are frequently invoked while describing this moment. The announcement of the deformation is felt like a brutal intrusion in representations associated to pregnancy. Then, we can observe a kind of disinvestment of the coming baby. Through our study, we find that high stress has not always a bad issue on relationship between parents and infants. In contrary, this kind of chronic stress can preserve the well-being of the relationship, especially for fatherhood. The time of facial deformation announcement also plays its part in representations about the baby. Before birth, it opens room for reordering and modifying representations, then the baby will be accepted as it should be on his birthday.
Resumo:
Abstract¿La deteción del espectro libre para las comunicaciones inalámbricas en un momento puntual es una tarea compleja cuyo desarrollo se simplica al realizarse de forma distribuida por una red de radio cognitiva. Sin embargo existes dificultades y vulnerabilidades de seguridad que han de ser tenidas en cuenta y solventadas a la hora de autenticar y validar los nodos de la red. Este artículo presenta una propuesta de mejora del protocolo fully distributed decision making protocol for CRN con el fin de llevar a cabo esta tarea de detección del espectro de una manera eficiente y segura.
Resumo:
BACKGROUND: Caring for individuals with schizophrenia can create distress for caregivers which can, in turn, have a harmful impact on patient progress. There could be a better understanding of the connections between caregivers' representations of schizophrenia and coping styles. This study aims at exploring those connections. METHODS: This correlational descriptive study was conducted with 92 caregivers of individuals suffering from schizophrenia. The participants completed three questionnaires translated and validated in French: (a) a socio-demographic questionnaire, (b) the Illness Perception Questionnaire for Schizophrenia and (c) the Family Coping Questionnaire. RESULTS: Our results show that illness representations are slightly correlated with coping styles. More specifically, emotional representations are correlated to an emotion-focused coping style centred on coercion, avoidance and resignation. CONCLUSION: Our results are coherent with the Commonsense Model of Self-Regulation of Health and Illness and should enable to develop new interventions for caregivers.
Resumo:
Este artículo presenta una propuesta de mejora del protocolo fully distributed decision making protocol for CRN con el fin de llevar a cabo la tarea de detección del espectro libre para las comunicaciones inalámbricas de una manera eficiente y segura.
Resumo:
Child sexual abuse is associated with problems in children's emotional development, particularly increased insecurity of attachment. However, few studies have examined its effect on the organization of attachment representations in preschoolers, and the findings of those that have been conducted have not been entirely consistent. Therefore, this study aims to analyze the effect of child sexual abuse on attachment representation quality in a sample of children 3 to 7 years old in Chile. The results indicate child sexual abuse does affect children's attachment representation quality. The attachment narratives of child sexual abuse victims scored significantly higher than nonvictims on the hyperactivity and disorganization dimensions of attachment. These results are discussed in terms of attachment theory, clinical findings on child sexual abuse, and clinical implications.
Resumo:
This paper discusses social representations in scientific communications and private ones that are linked to the individual imagination. Social representations, in a limited sense, are useful for the development of preventive messages, but of little benefit to clinical work. We highlight some non-explicit aspects of scientific discourse that impact on treatment: projected beliefs and values. We tackle the relationship between the concepts of representation, imagination, identity and temporality in the individual approach of the cancer patient.
Resumo:
We compute the exact vacuum expectation value of 1/2 BPS circular Wilson loops of TeX = 4 U(N) super Yang-Mills in arbitrary irreducible representations. By localization arguments, the computation reduces to evaluating certain integrals in a Gaussian matrix model, which we do using the method of orthogonal polynomials. Our results are particularly simple for Wilson loops in antisymmetric representations; in this case, we observe that the final answers admit an expansion where the coefficients are positive integers, and can be written in terms of sums over skew Young diagrams. As an application of our results, we use them to discuss the exact Bremsstrahlung functions associated to the corresponding heavy probes.
Resumo:
The thesis addresses the issue of parenthood and gender equality in Switzerland through the emergence of parental leave policies. This is an original and relevant research topic, as Switzerland is one of the few industrialized countries that have not yet implemented a parental or paternity leave. I first describe the emergence of parental leave policies in the last ten to fifteen years in the political, media, and labor-market spheres. Secondly, adopting a gender and discursive theoretical approach, I analyze whether and to what extent this emergence challenged gendered representations and practices of parenthood. The multilevel and mixed-methods research design implies analyzing various data sets such as parliamentary interventions (N=23J and newspaper articles (N=579) on parental leave policies. A case study of a public administration which implemented a one-month paid paternity leave draws on register data of leave recipients (N=95) and in-depth interviews with fathers and managers (n=30). Results show that parental leave policies, especially in recent years, have been increasingly problematized in the three social spheres considered, as a result of political and institutional events. While there is a struggle over the definition of the legitimate leave type to implement [parental or paternity leave) in the political sphere, paternity leave has precedence in the media and labor-market spheres. Overall, this emergence contributes to making fatherhood visible in the public sphere, challenging albeit in a limited way gendered representations and practices of parenthood. Along with representations of involved fatherhood and change in gender relations, different roles and responsibilities are attributed to mothers and fathers, the latter being often defined as secondary, temporary and optional parents. Finally, I identify a common trend, namely the increasing importance of the economic aspects of parental leave policies with the consequence of sidelining their gender-equality potential. The dissertation contributes to the literature which analyzes the interconnections between the macro-, the meso- and the micro-levels of society in the constitution of gender relations and parenthood. It also provides useful tools for the analysis of the politics of parental leave policies in Switzerland and their effects for gender equality. - Cette thèse traite de la parentalité et de l'égalité de genre en Suisse à travers l'émergence des congés parentaux. Ce sujet de recherche est original et pertinent puisque la Suisse est à ce jour un des seuls pays industrialisés à ne pas avoir adopté de droit au congé parental ou paternité. Cette recherche décrit l'émergence des congés parentaux au cours des 10 à 15 dernières années dans les sphères politique, médiatique et du marché de l'emploi en Suisse. En combinant perspective de genre et analyse de discours, elle examine dans quelle mesure cette émergence remet en question les représentations et pratiques genrées de parentalité. Des méthodes de recherche mixtes sont employées pour analyser des interventions parlementaires (N=23) et des articles de presse (N=579) sur les congés parentaux. L'étude de cas d une entreprise publique qui a adopté un congé paternité payé d'un mois s'appuie sur des données de registre (N=95) et des entretiens semi-structurés avec des pères et des cadres (n=30). Les résultats indiquent que dans les trois sphères considérées, les congés parentaux ont reçu une attention croissante au cours de ces dernières années, en lien avec des événements politiques et institutionnels. Alors que dans la sphère politique il n'y a pas de consensus quant au type de congé considéré comme légitime (congé parental ou paternité), dans les sphères médiatique et du marché de l'emploi le congé paternité semble l'emporter. Dans l'ensemble, l'émergence des congés parentaux contribue à rendre la paternité plus visible dans l'espace public, remettant en question-bien que d'une manière limitée-les représentations genrées de la parentalité. En effet, d'une part l'image de pères impliqués et de rapports de genre plus égalitaires au sein de la famille est diffusée. D'autre part, mères et pères continuent à être associés à des rôles différents, les pères étant définis comme des parents secondaires et temporaires. Finalement, l'analyse révèle une tendance générale, soit l'importance croissante accordée aux aspects économiques des congés parentaux, avec pour conséquence la mise à l'écart de leur potentiel pour l'égalité de genre. Cette thèse contribue à la recherche sur les liens entre les niveaux macro- meso- et microsociaux dans la constitution des rapports de genre et de la parentalité. Elle propose également des outils pour analyser les politiques de congés parentaux en Suisse et leurs implications pour l'égalité de genre.