888 resultados para Reproducing Kernel


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A partir d'un terrain ethnographique réalisé au sein d'une équipe mobile de soins palliatifs d'un hôpital universitaire, cette thèse de doctorat porte sur les médicaments dans le contexte de la fin de vie. Au carrefour d'une socio-anthropologie de la maladie grave, du mourir et des médicaments, elle interroge les rapports à la morphine, ainsi qu'à certains psychotropes et sédatifs utilisés en soins palliatifs. Entre temporalité vécue et temporalité institutionnelle, les manières d'investir le temps lorsqu'il est compté, y sont centrales. Dans une dimension microsociale, les résultats montrent que l'introduction de certains médicaments comme la morphine et l'entrée en scène d'une équipe mobile de soins palliatifs sont des points de repère et peuvent sonner comme une annonce, sorte de sanction, dans la trajectoire incertaine de la personne malade. En outre, les médicaments permettent d'agir sur « le temps qui reste » en plus de soulager les symptômes lorsque la maladie grave bascule en maladie incurable. Ils font l'objet d'usages détournés du but initial de soulagement des symptômes pour repousser, altérer ou accélérer la mort dans une perspective de maîtrise de sa fin de vie. Dans une dimension mésosociale, ce travail considère les médicaments à la base d'échanges entre groupements professionnels sur fond d'institutionnalisation des soins palliatifs par rapport à d'autres segments de la médecine actifs dans la gestion de la fin de vie. Dans une médecine caractérisée par l'incertitude et les décisions -avec une teinte toute particulière en Suisse où le suicide assisté est toléré - les médicaments en soins palliatifs peuvent être considérés comme des instruments de mort, qu'ils soient redoutés ou recherchés. Interrogeant les risques de reproduire un certain nombre d'inégalités de traitements à l'approche de la mort, qui s'accentuent dans un contexte de plus en plus favorable aux pratiques euthanasiques, ce travail se propose, en définitive, de discuter le temps contraint de la mort dans les institutions hospitalo-universitaires, entre acharnement et abstention thérapeutique.¦-¦Based on ethnographie fieldwork conducted within a palliative care mobile team in an academic hospital, this doctoral thesis focuses on medicines used in end of life contexts. At the intersection of a socio-anthropology of illness, dying and pharmaceuticals, the relations to morphine, as well as to some psychotropic and sedative drugs used in palliative care are questioned. Between "lived" experiences of temporality and institutional temporality, the ways by which actors invest time when it is counted, appeared to be central. In a microsocial dimension, the results showed that introducing drugs such as morphine, as well as the arrival of a palliative care mobile team, are landmarks and sound like an announcement, a sort of sanction, during the uncertain trajectory of the ill person. In addition, medicines can act on "the remaining time" when severe illness shifts into incurable illness. Indeed, medicines are being diverted from the initial aim of symptom relief in order to defer, alter or hasten death in a perspective of control over one's death. In a mesosocial dimension, pharmaceuticals are seen as core to professional exchanges and to palliative care institutionalisation compared to other active medical segments in end of life care. In a medical context characterised by uncertainty and decision-taking-with a special shade in Switzerland where assisted suicide is tolerated - palliative medicines can be seen as instruments of death, whether sought or feared. Questioning the risks of reproducing treatment inequalities at the approach of death, which are accentuated in a context increasingly favorable to euthanasia practices, this study aims, ultimately, at discussing death's constrained time in academic hospitals, between therapeutic intervention and abstention.

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It has been found that species of the digenetic genus Trypanosoma as well as species of monogenetic trypanosomatids of insects can grow in the lumen of the scent glands of opossums reproducing the cycle they perform in the intestinal tract of their insect hosts. Based on these findings, speculations are made on the incompletely known cycles of many mammalian trypanosomes and on the evolution of the family Trypanosomatidae.

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This paper presents a semisupervised support vector machine (SVM) that integrates the information of both labeled and unlabeled pixels efficiently. Method's performance is illustrated in the relevant problem of very high resolution image classification of urban areas. The SVM is trained with the linear combination of two kernels: a base kernel working only with labeled examples is deformed by a likelihood kernel encoding similarities between labeled and unlabeled examples. Results obtained on very high resolution (VHR) multispectral and hyperspectral images show the relevance of the method in the context of urban image classification. Also, its simplicity and the few parameters involved make the method versatile and workable by unexperienced users.

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Difficult tracheal intubation assessment is an important research topic in anesthesia as failed intubations are important causes of mortality in anesthetic practice. The modified Mallampati score is widely used, alone or in conjunction with other criteria, to predict the difficulty of intubation. This work presents an automatic method to assess the modified Mallampati score from an image of a patient with the mouth wide open. For this purpose we propose an active appearance models (AAM) based method and use linear support vector machines (SVM) to select a subset of relevant features obtained using the AAM. This feature selection step proves to be essential as it improves drastically the performance of classification, which is obtained using SVM with RBF kernel and majority voting. We test our method on images of 100 patients undergoing elective surgery and achieve 97.9% accuracy in the leave-one-out crossvalidation test and provide a key element to an automatic difficult intubation assessment system.

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La finalitat d'aquest projecte és aconseguir representar codis binaris no lineals de manera eficient en un ordinador. Per fer-ho, hem desenvolupat funcions per representar un codi binari a partir del super dual. Hem millorat la funció de càlcul del kernel d'un codi binari, implementada en projectes d'anys anteriors. També hem desenvolupat un paquet software per l'intèrpret MAGMA. Aquest paquet ens proveeix d'eines per al tractament de codis binaris no necessàriament lineals.

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El projecte recull el treball portat a càrrec per l’anàlisi, disseny i implementació d’una eina per l’Institut Municipal D’Hisenda de l’Ajuntament de Barcelona que compleixi les necessitats d’un sistema d’informació capaç de gestionar els expedients que genera una sèrie de tributs, les sancions que comporten així com la documentació necessària per la comunicació amb el ciutadà. Per realitzar l’aplicació s’han utilitzat tecnologies que ens permeten treballar en l’entorn web, un nucli programat en llenguatge Java sobre la plataforma MVC de Struts, tot sobre un servidor d’aplicacions WebSphere i un motor de base de dades Oracle.

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Aim Niche conservatism, or the extent to which niches are conserved across space and time, is of special concern for the study of non-native species as it underlies predictions of invasion risk. Based on the occurrence of 28 non-native birds in Europe, we assess to what extent Grinnellian realized niches are conserved during invasion, formulate hypotheses to explain the variation in observed niche changes and test how well species distribution models can predict non-native bird occurrence in Europe. Location Europe. Methods To quantify niche changes, a recent method that applies kernel smoothers to densities of species occurrence in a gridded environmental space was used. This corrects for differences in the availability of environments between study areas and allows discrimination between 'niche expansion' into environments new to the species and 'niche unfilling', whereby the species only partially fills its niche in the invaded range. Predictions of non-native bird distribution in Europe were generated using several distribution modelling techniques. Results Niche overlap between native and non-native bird populations is low, but niche changes are smaller for species having a higher propagule pressure and that were introduced longer ago. Non-native birds in Europe occupy a subset of the environments they inhabit in their native ranges. Niche expansion into novel environments is rare for most species, allowing species distribution models to accurately predict invasion risk. Main conclusions Because of the recent nature of most bird introductions, species occupy only part of the suitable environments available in the invaded range. This signals that apart from purely ecological factors, patterns of niche conservatism may also be contingent on population-specific historical factors. These results also suggest that many claims of niche differences may be due to a partial filling of the native niche in the invaded range and thus do not represent true niche changes.

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AIMS/HYPOTHESIS: MicroRNAs are key regulators of gene expression involved in health and disease. The goal of our study was to investigate the global changes in beta cell microRNA expression occurring in two models of obesity-associated type 2 diabetes and to assess their potential contribution to the development of the disease. METHODS: MicroRNA profiling of pancreatic islets isolated from prediabetic and diabetic db/db mice and from mice fed a high-fat diet was performed by microarray. The functional impact of the changes in microRNA expression was assessed by reproducing them in vitro in primary rat and human beta cells. RESULTS: MicroRNAs differentially expressed in both models of obesity-associated type 2 diabetes fall into two distinct categories. A group including miR-132, miR-184 and miR-338-3p displays expression changes occurring long before the onset of diabetes. Functional studies indicate that these expression changes have positive effects on beta cell activities and mass. In contrast, modifications in the levels of miR-34a, miR-146a, miR-199a-3p, miR-203, miR-210 and miR-383 primarily occur in diabetic mice and result in increased beta cell apoptosis. These results indicate that obesity and insulin resistance trigger adaptations in the levels of particular microRNAs to allow sustained beta cell function, and that additional microRNA deregulation negatively impacting on insulin-secreting cells may cause beta cell demise and diabetes manifestation. CONCLUSIONS/INTERPRETATION: We propose that maintenance of blood glucose homeostasis or progression toward glucose intolerance and type 2 diabetes may be determined by the balance between expression changes of particular microRNAs.

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The carob tree (Ceratonia siliqua) shows interesting prospects for some coastal Mediterranean growing areas and is widely used for industrial, agricultural, and ornamental purposes. It can be an alternative crop adapted to part-time farming and can also be used to regenerate vegetation in areas with a mild climate and erosion problems. Four Spanish carob cultivars were examined (Banya de Cabra, Duraio, Matalafera, and Rojal) to determine the one that performed the best for planting new orchards in northeastern Spain (Catalonia). The trees in this rain-fed trial (average rainfall of 500 mm) were planted in 1986 using seedling rootstocks that were budded in 1987. The trees were trained using the free-vase system and were spaced 8 x 9 m (138 trees/ha including 12% pollinators). The results showed that ‘Rojal’ was the earliest bearing cultivar. However, no significant differences were observed for cumulative pod production 18 years after budding. With respect to cumulative seed yield, ‘Duraio’ had the highest production (95 kg/tree). The lowest tree vigor (trunk cross-section) was observed in ‘Matalafera’. ‘Rojal’ trees produced the largest pods (average fruit weight of 18.9 g) and lowest seed content (11.8%), while ‘Banya de Cabra’ and ‘Duraio’ produced the smallest fruit (weighing 15.3 and 16.2 g, respectively) with the highest seed content (15.2% and 17.3%, respectively). Gum content, expressed as a percentage of the dry weight, was highest in ‘Duraio’ (56.9%) and was lowest in ‘Rojal’ (54.1%). Thus, in terms of kernel and pod production, ‘Duraio’ appeared to be the best-performing female cultivar for planting new carob orchards

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Arbuscular mycorrhizal fungi (AMF) are ancient asexually reproducing organisms that form symbioses with the majority of plant species, improving plant nutrition and promoting plant diversity. Little is known about the evolution or organization of the genomes of any eukaryotic symbiont or ancient asexual organism. Direct evidence shows that one AMF species is heterokaryotic; that is, containing populations of genetically different nuclei. It has been suggested, however, that the genetic variation passed from generation to generation in AMF is simply due to multiple chromosome sets (that is, high ploidy). Here we show that previously documented genetic variation in Pol-like sequences, which are passed from generation to generation, cannot be due to either high ploidy or repeated gene duplications. Our results provide the clearest evidence so far for substantial genetic differences among nuclei in AMF. We also show that even AMF with a very large nuclear DNA content are haploid. An underlying principle of evolutionary theory is that an individual passes on one or half of its genome to each of its progeny. The coexistence of a population of many genomes in AMF and their transfer to subsequent generations, therefore, has far-reaching consequences for understanding genome evolution.

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The rise and consequences of polyploidy in vertebrates, whose origin was associated with genome duplications, may be best studied in natural diploid and polyploid populations. In a diploid/tetraploid (2n/4n) geographic contact zone of Palearctic green toads in northern Kyrgyzstan, we examine 4ns and triploids (3n) of unknown genetic composition and origins. Using mitochondrial and nuclear sequence, and nuclear microsatellite markers in 84 individuals, we show that 4n (Bufo pewzowi) are allopolyploids, with a geographically proximate 2n species (B. turanensis) being their maternal ancestor and their paternal ancestor as yet unidentified. Local 3n forms arise through hybridization. Adult 3n mature males (B. turanensis mtDNA) have 2n mothers and 4n fathers, but seem distinguishable by nuclear profiles from partly aneuploid 3n tadpoles (with B. pewzowi mtDNA). These observations suggest multiple pathways to the formation of triploids in the contact zone, involving both reciprocal origins. To explain the phenomena in the system, we favor a hypothesis where 3n males (with B. turanensis mtDNA) backcross with 4n and 2n females. Together with previous studies of a separately evolved, sexually reproducing 3n lineage, these observations reveal complex reproductive interactions among toads of different ploidy levels and multiple pathways to the evolution of polyploid lineages.

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Plant-parasitic nematodes are major agricultural pests worldwide and novel approaches to control them are sorely needed. We report the draft genome sequence of the root-knot nematode Meloidogyne incognita, a biotrophic parasite of many crops, including tomato, cotton and coffee. Most of the assembled sequence of this asexually reproducing nematode, totaling 86 Mb, exists in pairs of homologous but divergent segments. This suggests that ancient allelic regions in M. incognita are evolving toward effective haploidy, permitting new mechanisms of adaptation. The number and diversity of plant cell wall-degrading enzymes in M. incognita is unprecedented in any animal for which a genome sequence is available, and may derive from multiple horizontal gene transfers from bacterial sources. Our results provide insights into the adaptations required by metazoans to successfully parasitize immunocompetent plants, and open the way for discovering new antiparasitic strategies.

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Treball de recerca realitzat per una alumna d'ensenyament secundari i guardonat amb un Premi CIRIT per fomentar l'esperit científic del Jovent l'any 2009. El treball es centra en conèixer la complexitat d’un estudi fotogràfic del s. XIX: l’estudi Napoleón. Per entendre tots els aspectes que implicava fer una fotografia en aquest estudi comença explicant com es van desenvolupar i descobrir les diferents tècniques fotogràfiques, després presenta l’estat de la fotografia a la Catalunya del s. XIX. El nucli del treball té diferents aspectes: per una banda s’investiga la història dels fundadors d’un dels estudis més importants a la Barcelona del s. XIX, per l’altra presenta com eren les sales, els decorats, els clients, la tipografia, les càmeres .... i per últim, porta a la pràctica tot allò necessari per a transformar un paper blanc en una fotografia fent servir els mètodes de l’època. Podríem dir que el treball es desenvolupa en tres àmbits: el primer sobre els fonaments tècnics i històrics de la fotografia, les fonts utilitzades per realitzar aquest apartat han estat fonamentalment bibliogràfiques; el segon fa referència a l’estudi fotogràfic dels Napoleón, en aquest cas, a part de les fonts bibliogràfiques, també ha estat de vital importància la informació aportada per un descendent de la família i finalment s’explica els procediments que es van fer servir per obtenir imatges durant el segle s.XIX i les reaccions químiques en les quals es fonamenten. Aporta també una part experimental que dóna un caire artístic i novedós al treball.

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We present a real data set of claims amounts where costs related to damage are recorded separately from those related to medical expenses. Only claims with positive costs are considered here. Two approaches to density estimation are presented: a classical parametric and a semi-parametric method, based on transformation kernel density estimation. We explore the data set with standard univariate methods. We also propose ways to select the bandwidth and transformation parameters in the univariate case based on Bayesian methods. We indicate how to compare the results of alternative methods both looking at the shape of the overall density domain and exploring the density estimates in the right tail.

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Abstract. Given a model that can be simulated, conditional moments at a trial parameter value can be calculated with high accuracy by applying kernel smoothing methods to a long simulation. With such conditional moments in hand, standard method of moments techniques can be used to estimate the parameter. Because conditional moments are calculated using kernel smoothing rather than simple averaging, it is not necessary that the model be simulable subject to the conditioning information that is used to define the moment conditions. For this reason, the proposed estimator is applicable to general dynamic latent variable models. It is shown that as the number of simulations diverges, the estimator is consistent and a higher-order expansion reveals the stochastic difference between the infeasible GMM estimator based on the same moment conditions and the simulated version. In particular, we show how to adjust standard errors to account for the simulations. Monte Carlo results show how the estimator may be applied to a range of dynamic latent variable (DLV) models, and that it performs well in comparison to several other estimators that have been proposed for DLV models.