• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 104
  • 101
  • 95
  • 17
  • 10
  • 10
  • 4
  • 4
  • 3
  • 3
  • 2
  • 2
  • 2
  • 1
  • 1
  • Tagged with
  • 384
  • 39
  • 36
  • 35
  • 32
  • 31
  • 31
  • 29
  • 25
  • 19
  • 18
  • 17
  • 17
  • 16
  • 16
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
261

Dévelopement d'outils microfluidiques appliqués à la biologie. Réalisation de dispositifs de tri cellulaire magnétique vertical.

Cargou, Sébastien 03 March 2014 (has links) (PDF)
Grâce aux avancées de la recherche de ces dix dernières années, qui ont permis l'implémentation de plus en plus de fonctions au sein d'un système microfluidique, les " laboratoires sur puce " connaissent un essor important notamment dans le domaine de la santé. Les premiers dispositifs voient le jour dans le domaine commercial, mais un verrou important reste d'identifier des éléments circulants en faible concentration dans le sang par exemple. Les techniques de séparation simples, efficaces et modulables sont la clef de cette problématique. Nous présentons dans ce travail une voie originale de séparation magnétique grâce à des bobines planaires en cuivre combinées à un système microfluidique 3D permettant une séparation verticale efficace. L'étude consiste en la conception, la modélisation, la réalisation et le test de dispositifs appliqués à des solutions tests constituées de billes magnétiques dans un premier temps, puis de composés biologiques de culture. La réalisation des laboratoires sur puce a été faite par des procédés de photolithographie et grâce à une technologie originale de laminage de film sec. De par sa très bonne robustesse, dans le temps et face aux solvants, ainsi que sa biocompatibilité, la SU-8 est un candidat de choix pour la réalisation de ces LOC. Cette technologie nous a permis de réaliser des dispositifs tout-polymère tridimensionnels et intégrant des fonctions actives dont l'actionnement magnétique. La microélectronique a depuis longtemps permis de miniaturiser tous les éléments électroniques courants tels les capteurs et les bobines. Il est alors très intéressant de voir comment nous pouvons les intégrer dans un dispositif microfluidique pour créer des fonctions plus complexes. Nous avons pu ainsi démontrer une séparation continue de monocyte THP1 de culture avec une efficacité de 82% et des voies d'amélioration prometteuses validées avec des billes magnétiques.
262

Développement de biopuces dédiées au tri d'échantillons cellulaires

Bombera, Radoslaw 05 December 2011 (has links) (PDF)
Le présent travail de thèse repose sur la conception d'un système miniaturisé de type biopuce capable d'assurer la capture et le relargage contrôlé de différentes populations des cellules sanguines (e.g. lymphocytes). Ce projet a pour objectif la construction d'un outil potentiel de recherche dans le domaine de l'immunologie ainsi que du diagnostic qui permettrait non seulement de réaliser des essais à partir d'une faible quantité d'échantillon, mais aussi de réduire le temps d'analyse. L'approche consiste plus précisément en la fabrication d'une matrice d'oligonucléotides et l'immobilisation de cellules via une molécule hybride composée d'un anticorps IgG couplé à une séquence d'oligonucléotide complémentaire. La synthèse du produit conjugué est mise en place et conduit à l'assemblage functionnel sur biopuce. Une fois les cellules spécifiquement capturées sur la surface, deux voies de rélargage contrôlé sont explorées. Ainsi, les lymphocytes sont libérées de façon contrôlée et séquentielle par clivage enzymatique d'ADN ou alors par désorption physique possible grâce au chauffage localisé. La détection se fait en temps réel par l'imagerie de la résonance plasmonique de surface (Surface Plasmon Resonance Imaging, SPRi) qui présente l'avantage de pouvoir suivre les phénomènes biomoléculaires en absence de marquage et d'apporter une réponse simultanée d'un échantillon biologique sur un grand nombre des sondes. Accessoirement, une approche instrumentale particulière nous permet d'observer les étapes de capture/relargage par microscopie optique classique. La construction de la biopuce permet également l'élargissement à plusieurs cibles et ouvre ainsi la voie à de nombreuses possibilités d'exploration en termes d'application pour l'analyse d'échantillons biologiques plus complexes tels que du sang.
263

Etude du système quasi-unidimensionnel AxA'1-xNb2O6 (A et A'= Ni, Fe et Co) : préparation et caractérisation des propriétés structurales et magnétiques

Sarvezuk, Paulo 27 October 2011 (has links) (PDF)
Cette étude expérimentale est consacrée à la structure cristalline et aux propriétés magnétiques des phases orthorhombiques ANb2O6 (A = métaux magnétiques) qui ont retenues notre attention en tant que système Ising modèle quasi 1D. Ce comportement magnétique original de basse dimension résulte à la fois de la force des interactions magnétiques le long des chaînes d'atomes magnétiques quasi-unidimensionnelles, et à la faiblesse des interactions entre les chaînes qui sont de nature antiferromagnétique. Lorsque ces composés sont ordonnés l'ensemble de ces interactions inter et intra chaîne conduit à un ordre antiferromagnétique. Notre investigation s'appuie sur une caractérisation systématique de la série de composés AxA'1-xNb2O6 (A et A' = Ni, Fe et Co), par des mesures variées et complémentaires, notamment: diffraction des rayons X à température ambiante, diffraction de neutrons au dessus et en dessous de la température d'ordre magnétique, mesures magnétiques : évolution thermique de courbes d'aimantation isochamp et mesures d'aimantation isotherme. De plus, des mesures de la chaleur spécifique et de spectroscopie Mössbauer ont été réalisées sur certains échantillons sélectionnés. Nous avons mis à jour, selon la concentration, des comportement très différents dans les systèmes pseudo binaires Fe-Co, Ni-Fe ou Co-Ni qui peuvent soit présenter un état ordonné soit conserver un état paramagnétique jusqu'à de très basses températures. Nos mesures démontrent que la température d'ordre magnétique et les vecteurs de propagations diffèrent sensiblement selon la composition car ces systèmes sont caractérisés par une compétition entre les interactions magnétiques mises en jeu dans un réseau triangulaire interchaines. Cette étude montre que le désordre cationique Fe/Co induit une réduction substantielle des interactions tant inter que intra chaînes, ce qui traduit la tendance à défavoriser l'établissement d'un ordre magnétique à longue portée. De manière similaire, le système NixFe1-xNb2O6 ne présente pas d'ordre magnétique pour x=0,2 et ceci jusqu'à 400 mK au moins.
264

Efecto del número de opciones de respuesta sobre las propiedades psicométricas de los cuestionarios de personalidad

Kramp Denegri, Uwe Arthur 14 September 2006 (has links)
¿Cuántas opciones de respuesta hay que utilizar para responder un cuestionario de personalidad? Durante más de ochenta años, numerosas investigaciones previas han examinado este tópico sin lograr alcanzar un consenso. El presente trabajo se aborda esta cuestión de forma exhaustiva.MÉTODO:Se aplican dos escalas de personalidad [(Orientación Negativa hacia los Problemas (NPO) del Social Problem Solving Inventory-Revised (SPSI-R) y la escala Satisfacción con la Vida (SWLS)], cada una a una muestra independiente (Estudio A = 746 participantes y Estudio B = 426 participantes), variando el número de opciones de respuesta en dos, tres y cinco alternativas. Cada sujeto debe responder a los tres tipos de formato de respuesta dentro de una misma sesión. Para evitar que éstos noten que están contestando el mismo cuestionario en más de una ocasión, cada escala experimental se inserta dentro de una batería de "tests". De esta forma, se construyen tres baterías de "test" (una para cada muestra), contrabalanceando la aparición de los distintos formatos de respuesta y manteniendo constante el resto de las condiciones experimentales. Por otro lado, se utiliza como criterio para evaluar el efecto del número de opciones de respuesta sobre las propiedades psicométricas las escalas NPO y SWLS tanto su fiabilidad (consistencia interna y estabilidad temporal) como su validez (evidencia basada en la estructura interna y evidencia basada en el grado de relación con otras variables).Estas se evalúan desde tres modelos psicométricos diferentes: Teoría Clásica de los Tests (TCT), Análisis Factorial de los Ítems (AFI) y Teoría de Respuesta a los Ítems (TRI).APORTE:Tres son los principales aportes de este trabajo de Tesis de Doctorado. En primer lugar, se aplican dos escalas de personalidad diferentes a muestras independientes, manteniendo constante el resto de las condiciones experimentales. Con ello se espera controlar que los resultados observados son producto del efecto ejercido por los distintos formatos de respuesta utilizados y no por otras variables. En segundo lugar, cada sujeto contesta su respectiva escala experimental utilizando los tres formatos de respuesta propuestos. Ello permite disponer de información directa respecto de cómo ha respondido realmente cada sujeto -y no sólo con una estimación indirecta, derivada de la comparación de muestras independientes, como ha sido lo habitual hasta este momento. Finalmente, el análisis de las propiedades psicométricas de las escalas experimentales se aborda por primera vez, simultáneamente, desde tres perspectivas diferentes (TCT, AFI y TRI). Esto permite controlar que los resultados observados no son consecuencia inmediata del modelo psicométrico utilizado, sino producto del efecto ejercido por los distintos formatos de respuesta propuestos. El análisis de la validez de los cuestionarios se realiza aplicando Modelos de Ecuaciones Estructurales (SEM).RESULTADOS Y DISCUSIÓN:En su conjunto, los resultados observados sugieren que el número de opciones de respuesta afecta de forma leve a moderada la estructura interna y, parcialmente, la consistencia interna de las escalas utilizadas en este trabajo de Tesis de Doctorado. Por el contrario, el número de alternativas de respuesta no afecta aspectos tales como la evidencia basada en la relación con otras variables o la estabilidad temporal (estabilidad test-retest) de las escalas analizadas.PALABRAS CLAVE:Número óptimo de opciones de respuesta, Cuestionarios de personalidad, Satisfaction with Life Scale (SWLS), Social Problem-Solving Inventory-Revised (SPSI-R), Teoría Clásica de los Tests (TCT), Análisis Factorial de los Ítems (AFI), Teoría de Respuesta a los Ítems (TRI), Modelos de Ecuaciones Estructurales (SEM), Propiedades psicométricas, Fiabilidad, Validez, evidencia basada en la estructura interna, evidencia basada en la relación con otras variables, consistencia interna, estabilidad temporal. / Numerous studies have attempted to answer the question of what is the optimal number of response options in personality questionnaires. Some authors argue that the number of response options do not affect at all the reliability or the validity of the measurement tool, whereas others suggest to use from 2- to 25-response alternatives in order to maximize the psychometric properties of the instrument. The present PhD Dissertation work attempts to aboard in an exhaustive manner this question.METHOD:All subjects have responded, within the same session, a questionnaire with two-, three- and five-response options. In order to avoid that the subjects notice that they are responding to the same questionnaire, within a same session, these are applied within a tests battery. Likewise, two independent samples (A and B) and two personality questionnaires [Negative Problem Orientation (NPO) of the Social Problem Solving Inventory-Revised (SPSI-R) and Satisfaction with Life Scale (SWLS)] are used, to ensure that the answer does not depend on the instrument investigated. Both, the reliability and validity of the instrument will be used as criteria to determine the optimum number of response alternatives. Finally, the reliability and validity of each response format is analysed using three different psychometric models: "Classical Test Theory" (CTT), "Item Factor Analysis" (IFA), and "Item Response Theory" (IRT). Add, we used Structural Equation Models (SEM) to analyze the validity of the NPO and SWLS scales.RESULTS AND DISCUSSION:As a whole, the observed results suggest that the number of response options affects form slight to moderate aspects such as the internal structure and, partially, the internal consistency of the scales analyzed in this work. Contrary, the number of response alternatives does not affect aspects such as the evidence based on the relation with other variables or the temporary stability (test-retest stability) of the examined scales.KEYWORDS:Optimal number of response options, Classical Tests Theory (CCT), Item Factor Analysis (IFA), Item Response Theory (IRT), Structural Equation Models (SEM), Psychometric properties, Reliability, Validity, Personality rating scales, Satisfaction with Life Scale (SWLS), Social Problem-Solving Inventory-Revised (SPSI-R), evidence based on the internal structure, evidence based on the relation with other variables, internal consistency, temporary stability.
265

Fabrication, characterization, and modeling of metallic source/drain MOSFETs

Gudmundsson, Valur January 2011 (has links)
As scaling of CMOS technology continues, the control of parasitic source/drain (S/D) resistance (RSD) is becoming increasingly challenging. In order to control RSD, metallic source/drain MOSFETs have attracted significant attention, due to their low resistivity, abrupt junction and low temperature processing (≤700 °C). A key issue is reducing the contact resistance between metal and channel, since small Schottky barrier height (SBH) is needed to outperform doped S/D devices. A promising method to decrease the effective barrier height is dopant segregation (DS). In this work several relevant aspects of Schottky barrier (SB) contacts are investigated, both by simulation and experiment, with the goal of improving performance and understanding of SB-MOSFET technology:First, measurements of low contact resistivity are challenging, since systematic error correction is needed for extraction. In this thesis, a method is presented to determine the accuracy of extracted contact resistivity due to propagation of random measurement error.Second, using Schottky diodes, the effect of dopant segregation of beryllium (Be), bismuth (Bi), and tellurium (Te) on the SBH of NiSi is demonstrated. Further study of Be is used to analyze the mechanism of Schottky barrier lowering.Third, in order to fabricate short gate length MOSFETs, the sidewall transfer lithography process was optimized for achieving low sidewall roughness lines down to 15 nm. Ultra-thin-body (UTB) and tri-gate SB-MOSFET using PtSi S/D and As DS were demonstrated. A simulation study was conducted showing DS can be modeled by a combination of barrier lowering and doped Si extension.Finally, a new Schottky contact model was implemented in a multi-subband Monte Carlo simulator for the first time, and was used to compare doped-S/D to SB-S/D for a 17 nm gate length double gate MOSFET. The results show that a barrier of ≤ 0.15 eV is needed to comply with the specifications given by the International Technology Roadmap for Semiconductors (ITRS). / QC 20111206
266

Toolpath and Cutter Orientation Optimization in 5-Axis CNC Machining of Free-form Surfaces Using Flat-end Mills

Luo, Shan 24 December 2015 (has links)
Planning of optimal toolpath, cutter orientation, and feed rate for 5-axis Computer Numerical Control (CNC) machining of curved surfaces using a flat-end mill is a challenging task, although the approach has a great potential for much improved machining efficiency and surface quality of the finished part. This research combines and introduces several key enabling techniques for curved surface machining using 5-axis milling and a flat end cutter to achieve maximum machining efficiency and best surface quality, and to overcome some of the key drawbacks of 5-axis milling machine and flat end cutter use. First, this work proposes an optimal toolpath generation method by machining the curved surface patch-by-patch, considering surface normal variations using a fuzzy clustering technique. This method allows faster CNC machining with reduced slow angular motion of tool rotational axes and reduces sharp cutter orientation changes. The optimal number of surface patches or surface point clusters is determined by minimizing the two rotation motions and simplifying the toolpaths. Secondly, an optimal tool orientation generation method based on the combination of the surface normal method for convex curved surfaces and Euler-Meusnier Sphere (EMS) method for concave curved surfaces without surface gouge in machining has been introduced to achieve the maximum machining efficiency and surface quality. The surface normal based cutter orientation planning method is used to obtain the closest curvature match and longest cutting edge; and the EMS method is applied to obtain the closest curvature match and to avoid local gouging by matching the largest cutter Euler-Meusnier sphere with the smallest Euler-Meusnier sphere of the machined surface at each cutter contact (CC) point. For surfaces with saddle shapes, selection of one of these two tool orientation determination methods is based on the direction of the CNC toolpath relative to the change of surface curvature. A Non-uniform rational basis spline (NURBS) surface with concave, convex, and saddle features is used to demonstrate these newly introduced methods. Thirdly, the tool based and the Tri-dexel workpiece based methods of chip volume and cutting force predictions for flat-end mills in 5-axis CNC machining have been explored for feed rate optimization to achieve the maximum material removal rate. A new approach called local parallel slice method which extends the Alpha Shape method - only for chip geometry and removal volume prediction has been introduced to predict instant cutting forces for dynamic feed rate optimization. The Tri-dexel workpiece model is created to get undeformed chip geometry, chip volume, and cutting forces by determining the intersections of the tool envelope and continuously updating the workpiece during machining. The comparison of these two approaches is made and several machining experiments are conducted to verify the simulation results. At last, the chip ploughing effects that become a more serious problem in micro-machining due to chip thickness not always being larger than the tool edge radius are also considered. It is a challenging task to avoid ploughing effects in micro-milling. A new model of 3D chip geometry is thus developed to calculate chip thickness and ploughing volume in micro 5-axis flat-end milling by considering the minimum chip thickness effects. The research forms the foundation of optimal toolpath, cutter orientation, cutting forces/volume calculations, and ploughing effects in 5-axis CNC machining of curved surfaces using a flat-end mill for further research and direct manufacturing applications. / Graduate / 0548 / luoshan@uvic.ca
267

Catégorisation de graphiques par les enseignants et les élèves / Teacher and student categorization of graphics into graphical genres

Ashraf, Muhammad 19 June 2014 (has links)
Les graphiques ont pris de plus en plus d'importance dans le matériel pédagogique, les manuels scolaires ou encore les programmes informatiques. Malgré la coexistence de différents types de graphiques ou de genres graphiques, jusqu'à maintenant, les recherches sur l'apprentissage ont seulement pris en compte la distinction entre le texte et l'image. Cette thèse vise à éclaircir ce qui, dans la recherche sur l'apprentissage, semble être une catégorie globale et indivisible : les représentations visuelles. Nous nous sommes concentrées sur ce que pensent des enseignants et des étudiants de Master concernant différents types de représentations visuelles et leurs fonctions présumées dans l'enseignement et l'apprentissage. A l'heure actuelle, la recherche sur les graphiques est principalement axée sur la compréhension des élèves. Il existe très peu de recherches sur la compréhension des graphiques par les enseignants. En outre, la dimension de la formation des enseignants aux graphiques est, elle aussi, relativement ignorée. La thèse se présente en deux parties : une recherche théorique suivie d'une recherche empirique. La première partie du travail examine la littérature relative aux représentations graphiques dans l'histoire, dans les programmes scolaires à travers le monde ainsi que leur utilisation dans l'enseignement et l'apprentissage. Elle expose également les classifications des différents types de graphiques. La seconde partie de la thèse prend appui sur trois enquêtes menées auprès d'enseignants en activité et d'étudiants de Master en formation. La première investigue la compréhension des graphiques d'enseignants en activité en France et au Pakistan. Les deux autres ont été conduites auprès de futurs enseignants, en utilisant la méthode du tri de carte, afin d'identifier leurs compétences relatives à la catégorisation des différents types de graphiques.En conclusion, il semble que les programmes de formation des enseignants manquent d'un enseignement à la compréhension graphique. Même en géographie, pourtant considérée comme la discipline des graphiques et de leur enseignement, nous constatons que les enseignants sont peu familiers avec de nombreux genres graphiques. Dans l'ensemble, les graphiques génériques (camemberts, histogrammes, cartes et tableaux, etc.) ont été facilement identifiés par les enseignants alors que la classification des graphiques hybrides s'est révélée plus difficile pour la plupart d'entre eux. / Visualizations have gained more importance in pedagogical material, in text books and in computer programs. Despite the co-existence of many different types of visualizations or graphical genres, learning research only has taken into account the distinction between text and pictures. This thesis aims at unpacking what, at least in learning research, seems to be one single holistic indivisible category of visualizations. We focused on teachers' and Masters students' thoughts on the existence of different types of visualizations and their presumed function in teaching and learning. Research on graphical representations is mainly focused on students' comprehension of graphical representations. However, there is very little research in extend of teachers' comprehension of graphical representations. In addition, the aspect of teacher training of graphical representations is also relatively ignored. There are two main parts in this thesis: theoretical and empirical. In theoretical part, we presented the literature on the existence of graphical representations in worldwide curricula. Remarkable works of cartographers who played important rule for the advancement of graphic representations in context of teaching and learning. And finally, classification of different genres of graphical representations was also exhibited. Empirical part on the other hand, based on three studies conducted with in-service teachers and Masters students' about their comprehension of graphical genres. First study was conducted with in-service teachers from France and Pakistan to investigate their basic understanding of graphical representations. Second and third study explores the Masters' students' categorization of graphical representations. In conclusion, it seems that the teacher training programs lack the training of graphic comprehension. Even in the domain of geography which is considered the major domain about graphics and graphic education, teachers were observed unfamiliar with many graphic genres. Overall, Generic graphical representations (i.e. line graph, pie charts, bar charts, maps and tables etc.) were identified more comfortably. However, classification of hybrid graphical representations (i.e. combination of map and bar graph or other hybrid graphics) was slightly difficult for the participants.
268

PaVo un tri parallèle adaptatif / PaVo. An Adaptative Parallel Sorting Algorithm.

Durand, Marie 25 October 2013 (has links)
Les joueurs exigeants acquièrent dès que possible une carte graphique capable de satisfaire leur soif d'immersion dans des jeux dont la précision, le réalisme et l'interactivité redoublent d'intensité au fil du temps. Depuis l'avènement des cartes graphiques dédiées au calcul généraliste, ils n'en sont plus les seuls clients. Dans un premier temps, nous analysons l'apport de ces architectures parallèles spécifiques pour des simulations physiques à grande échelle. Cette étude nous permet de mettre en avant un goulot d'étranglement en particulier limitant la performance des simulations. Partons d'un cas typique : les fissures d'une structure complexe de type barrage en béton armé peuvent être modélisées par un ensemble de particules. La cohésion de la matière ainsi simulée est assurée par les interactions entre elles. Chaque particule est représentée en mémoire par un ensemble de paramètres physiques à consulter systématiquement pour tout calcul de forces entre deux particules. Ainsi, pour que les calculs soient rapides, les données de particules proches dans l'espace doivent être proches en mémoire. Dans le cas contraire, le nombre de défauts de cache augmente et la limite de bande passante de la mémoire peut être atteinte, particulièrement en parallèle, bornant les performances. L'enjeu est de maintenir l'organisation des données en mémoire tout au long de la simulation malgré les mouvements des particules. Les algorithmes de tri standard ne sont pas adaptés car ils trient systématiquement tous les éléments. De plus, ils travaillent sur des structures denses ce qui implique de nombreux déplacements de données en mémoire. Nous proposons PaVo, un algorithme de tri dit adaptatif, c'est-à-dire qu'il sait tirer parti de l'ordre pré-existant dans une séquence. De plus, PaVo maintient des trous dans la structure, répartis de manière à réduire le nombre de déplacements mémoires nécessaires. Nous présentons une généreuse étude expérimentale et comparons les résultats obtenus à plusieurs tris renommés. La diminution des accès à la mémoire a encore plus d'importance pour des simulations à grande échelles sur des architectures parallèles. Nous détaillons une version parallèle de PaVo et évaluons son intérêt. Pour tenir compte de l'irrégularité des applications, la charge de travail est équilibrée dynamiquement par vol de travail. Nous proposons de distribuer automatiquement les données en mémoire de manière à profiter des architectures hiérarchiques. Les tâches sont pré-assignées aux cœurs pour utiliser cette distribution et nous adaptons le moteur de vol pour favoriser des vols de tâches concernant des données proches en mémoire. / Gamers are used to throw onto the latest graphics cards to play immersive games which precision, realism and interactivity keep increasing over time. With general-propose processing on graphics processing units, scientists now participate in graphics card use too. First, we examine these architectures interest for large-scale physics simulations. Drawing on this experience, we highlight in particular a bottleneck in simulations performance. Let us consider a typical situation: cracks in complex reinforced concrete structures such as dams are modelised by many particles. Interactions between particles simulate the matter cohesion. In computer memory, each particle is represented by a set of physical parameters used for every force calculations between two particles. Then, to speed up computations, data from particles close in space should be close in memory. Otherwise, the number of cache misses raises up and memory bandwidth may be reached, specially in parallel environments, limiting global performance. The challenge is to maintain data organization during the simulations despite particle movements. Classical sorting algorithms do not suit such situations because they consistently sort all the elements. Besides, they work upon dense structures leading to a lot of memory transfers. We propose PaVo, an adaptive sort which means it benefits from sequence presortedness. Moreover, to reduce the number of necessary memory transfers, PaVo spreads some gaps inside the data structure. We present a large experimental study and confront results to reputed sort algorithms. Reducing memory requests is again more important for large scale simulations with parallel architectures. We detail a parallel version of PaVo and evaluate its interest. To deal with application irregularities, we do load balancing with work-stealing. We take advantage of hierarchical architectures by automatically distributing data in memory. Thus, tasks are pre-assigned to cores with respect to this organization and we adapt the scheduler to favor steals of tasks working on data close in memory.
269

A securitização do terrorismo no contexto sul-americano : dinâmicas das relações de segurança interamericanas no século XXI

Lammerhirt, Laura Vicentin January 2018 (has links)
O presente trabalho tem como objetivo analisar os processos de inserção do terrorismo na agenda de segurança sul-americana. Ele se enquadra nas Resoluções nº 114/2014 e 115/2014 da Câmara de Pós-Graduação da Universidade Federal do Rio Grande do Sul e, portanto, é dividido em três partes. A PARTE I consiste em uma contextualização do objeto de pesquisa, composta por uma descrição geral do objetivo do trabalho, bem como a delimitação do objeto, marco teórico e marco temporal. A PARTE II apresenta o artigo em si, o qual analisa os processos de securitização do terrorismo no Norte Andino, a partir da associação entre os movimentos guerrilheiros colombianos e o narcotráfico com o terrorismo, e no Cone Sul, através das suspeitas de financiamento de grupos extremistas islâmicos decorrente de atividades ilícitas na região da tríplice fronteira entre Argentina, Brasil e Paraguai. O objetivo consiste em demonstrar as maneiras com as quais o terrorismo foi inserido na agenda regional de segurança e as influências dos atores externos e internos nestes processos. Para tanto, foram utilizadas técnicas de analise qualitativa, com base nas contribuições da Escola de Copenhague, no âmbito dos Estudos de Segurança Internacional, no exame de documentos oficiais e mídias locais dos países envolvidos. A PARTE III apresenta a descrição da agenda de pesquisa a ser seguida. / This paper aims to analyze the processes of the insertion of terrorism in the South American security agenda. It is in accordance with Resolutions 114/2014 and 115/2014 of the Federal University of Rio Grande do Sul and is therefore divided into three parts. PART I consists in a contextualization of the object of research, composed by a general description of the paper’s objectives, as well as the delimitation of the object, theoretical framework, and timeframe. PART II presents the article itself, which analyzes the processes of securitization of terrorism in the Andean North, throughout the association between Colombian guerrilla movements and narcotrafficking with terrorism, and in the Southern Cone, through the suspicions of Islamic extremist groups financing due to illicit activities in the tri-border area between Argentina, Brazil and Paraguay. The main goal is to demonstrate the means through which terrorism was inserted in the regional security agenda and the influences of external and internal actors in these processes. In order to do so techniques of qualitative analysis were used, based on the contributions of the Copenhagen School, under the scope of International Security Studies, in the examination of official documents and local medias. PART III presents the description of the research agenda to be followed.
270

Desenvolvimento e validação preliminar de um instrumento breve para medir o estresse psicológico pré-operatório

Cunha, Maria de Nazaré Furtado January 2014 (has links)
INTRODUÇÃO: Pacientes candidatos à cirurgia frequentemente experimentam estresse, condição que os torna suscetíveis a desfechos desfavoráveis como exacerbação de dor, maior consumo de analgésicos e anestésicos, aumento no tempo de hospitalização, maior risco de infecção pós- operatória e aumento no risco de cronificação da dor pós-operatória. Embora seja conhecido que a carga de estresse emocional negativa aumente a morbimortalidade perioperatória, faltam instrumentos práticos desenvolvidos para captar as emoções vinculadas a este contexto. OBJETIVOS: Desenvolver um instrumento breve para medir o estresse psicológico pré-operatório (B-MEPS), tornando possível identificar pacientes mais vulneráveis e assim otimizar medidas de controle. PACIENTES E MÉTODOS: Neste estudo transversal foram incluídos 863 pacientes (643 mulheres) agendados para cirurgia eletiva. Idade entre 18 a 60 anos, classificados de acordo com o estado físico da Sociedade Americana da Anestesiologia (ASA) nas classes I-III. Os seguintes instrumentos foram aplicados: o Inventário de Ansiedade Traço-Estado (IDATE), a Escala de Depressão de Montgomery-Asberg, o Self-Reporting questionnaire (SRQ-20) e o Questionário de Expectativa de Futuro (FSPQ). A fim de selecionar os itens mais discriminativos em relação ao estresse, realizou-se uma análise exploratória usando cada um dos instrumentos. Os critérios utilizados no processo de seleção dos itens, por meio da análise discriminante, foram os candidatos à cirurgia por patologia oncológica ou terem reportado dor pós-operatória moderada a intensa [escore na Escala Análogo-Visual (EAV) > 30 mm]. Neste processo foram selecionados 24 itens, os quais foram ajustados utilizando o modelo de crédito parcial generalizado (GPCM), que é um modelo da Teoria de Resposta ao Item (TRI). A partir do GPCM foram selecionados 16 itens. A validade de face foi realizada por um Comitê de especialistas em medicina perioperatória. Os escores do B-MEPS foram correlacionados com o nível de dor reportado na EAV, na maior parte do tempo das primeiras 24 h do período pós-operatório e com o consumo de morfina pós-operatória quantificado em mg/dia. Esta versão refinada do B-MEPS foi aplicada a 40 pacientes (20 mulheres), ASA II-III, candidatos à cirurgia eletiva. Os escores da B-MEPS foram correlacionados com questões cuja valência semântica apresenta situações que expressam a interferência do estresse na vida diária. RESULTADOS: Inicialmente 24 itens com diferentes números de categorias ordinais foram selecionados a partir dos quatros instrumentos. No processo da GPCM, que objetivou dentre outras finalidades maximizar a confiabilidade, foi realizada a eliminação sequencial de itens internamente inconsistentes. Este processo foi finalizado quando não se observou melhora no nível de consistência nos 16 itens remanescentes, cujo coeficiente alfa de Cronbach foi de 0,83. A TRI propôs modificações nos itens de resposta pelas características das categorias nas Curvas de Resposta ao Item. A curva que avalia a relação entre a localização do conteúdo de traços latentes dos itens sugere que estes apresentam melhor desempenho para identificar níveis de estresse mais levados. O desempenho do conjunto final de itens foi correlacionado com variáveis clínicas relacionadas ao estresse emocional perioperatório como dor (r = 0,23, P < 0,01) e consumo de morfina (r = 0,17, P < 0,01). Um Comitê de experts em medicina perioperatória (N = 30) avaliou a clareza dos itens do B-MEPS usando uma escala análogo-visual de zero a 10. A média global do conjunto de itens foi 8.53 (1,54) e por sugestão deste Comitê o item 16 foi eliminado por falta de clareza. Dois itens do SRQ-20, que apresentavam possibilidade respostas dicotômicas, passaram a ter três possibilidades de respostas. Os escores da versão final preliminar do B-MEPS foram correlacionados com questões cuja valência semântica apresenta situações que expressam a interferência do estresse na vida diária, respondidas por pacientes candidatos à cirurgia eletiva, visando uma validação concorrente preliminar. CONCLUSÃO: Nosso estudo permitiu construir o B-MEPS, que é o resultado do refinamento do conjunto de itens selecionados a partir de instrumentos clássicos para avaliar a carga emocional negativa, a partir da TRI. O conjunto de itens remanescentes apresentou satisfatório nível de consistência interna e o seu escore está correlacionado ao nível de dor. A validação de face e uma pré-validação concorrente preliminar foram realizadas. Este estudo, portanto, concretiza a validação preliminar do B-MEPS como um instrumento útil para ser validado em futuro estudo prospectivo, com o intuito de avaliar a capacidade do B-MEPS predizer desfechos clínicos e orientar o planejamento de intervenções que possam para maximizar o cuidado perioperatório. Embora, este instrumento ainda possa sofrer pequenos ajustes ou adições de algum item após nova analise de TRI prevista após estudo prospectivo com grande numero de pacientes. / INTRODUCTION: Patients who are candidates for surgery often undergo stress, a condition that makes them susceptible to unfavorable outcomes, such as exacerbated pain, greater consumption of analgesic and anesthetics, longer stay in hospital, greater risk of postoperative infection and increased risk of chronification of postoperative pain. Although it is known that the amount of negative emotional stress increases perioperative morbidity and mortality, not many practical instruments have been developed to pick up the emotions connected to this context.. OBJECTIVES: To develop a brief instrument to measure preoperative emotional stress (B-MEPS), enabling the identification of more vulnerable patients and thus optimizing control measures. PATIENTS AND METHODS: In this cross-sectional study, 843 patients were included (643 women) scheduled for elective surgery, age between 18 and 60 years, classified according to the physical status of the American Society of Anesthesiology (ASA) in classes I-III. The following instruments were applied: the State and Trait Anxiety Inventory (STAI), the Montgomery-Asberg Depression Scale, the Self-Reporting Questionnaire (SRQ-20 and the Questionnaire on Expectations for the Future (FSPQ) Future self-perception questionnaire. In order to select the most discriminative items regarding stress, an exploratory analysis was performed using each of the instruments, The criteria used in the process of selecting the items, by means of discriminant analysis, are that they were candidates for surgery due to an oncological pathology, or that they had reported moderate to intense postoperative pain [score on the Analogue-Visual Scale AVS > 30 mm]. In this process 24 items were selected which were adjusted using the generalized partial credit model (GPCM), which is a model of the Theory of Response to Item (TRI). Sixteen items were selected based on the GPCM. The face validity was performed by a Committee of specialists in perioperative medicine. The B-MEPS scores were correlated with the level of pain reported in the AVS, mostly in the first 24 hours of the postoperative period, and with the consumption of morphine postoperatively, quantified as mg/day. This refined version of B-MEPS was applied to 40 ASA II-III patients (20 women) who were candidates for elective surgery. The B-MEPS scores were correlated with questions whose semantic valence present situations that express the interference of stress in everyday life. RESULTS: Initially, 24 items with different numbers of ordinal categories were selected based on the four instruments. In the GPCM process which, among other goals included maximizing reliability, the sequential elimination of internally inconsistent items was performed. This process was finalized, when no improvement was found in the level of consistency in the 16 remaining items, whose Cronbach’s Alpha coefficient was 0.83. The TRI proposed modifications in the response items due to the characteristics of the categories in the Curves of Response to the Item. The curve that evaluates the relationship between the location of the content of latent traits of the items suggests that these present a better performance to identify higher levels of stress. The performance of the final set of items was correlated with clinical variables related to perioperative emotional stress, such as pain (r = 0.23, P < 0.01) and consumption of morphine (r = 0.17, P < 0.01). A Committee of experts in perioperative medicine (N=30) evaluated the clarity of the items of B-MEPS using an analogue-visual scale from zero to 10.. The global mean of the set of items was 8.53 (1,54) and per suggestion of this Committee, item 16 was eliminated due to lack of clarity. Two items of the SRQ-20, which presented the possibility of dichotomous answers acquired three possible answers. The scores of the preliminary final version of B-MEPS were correlated with questions whose semantic valence presents situations that express the interference of stress in everyday life, answered by patients who were candidates to elective surgery, aiming at a preliminary concurrent validation. CONCLUSION: Our study allowed constructing B-MEPS, which is the result of the refinement of the set of items selected from classical instruments to evaluate the negative emotional load based on TRI. The set of remaining items presented a satisfactory level of internal consistency and its score is correlated with the level of pain. Face validation and a preliminary concurrent pre-validation were performed. This study, thus, materializes the preliminary validation of B-MEPS as a useful instrument to be validated in a future prospective study, aiming at evaluating the capacity of B-MEPS to predict clinical outcomes and guide the planning of interventions that can maximize perioperative care. However, this instrument may still undergo small adjustments or additions of some item after a new TRI analysis foreseen after a prospective study with a large number of patients.

Page generated in 0.0634 seconds