Teses / dissertações sobre o tema "158/.1"

Un réseau sans fil Ad hoc consiste en un groupe de noeuds mobiles facilement déployables sans l'existence d'une infrastructure préexistante. Chaque noeud joue le rôle d'un hôte/routeur et utilise le canal radio comme le seul moyen de communication. Le routage classique s'appuie souvent sur une vue à plat du réseau Ad hoc et utilise un mécanisme d'inondation des paquets de contrôle afin de maintenir les routes. Cette inondation crée des problèmes d'utilisation inefficace des ressources en termes de traitement, de capacité, d'énergie et de bande passante. Aucun protocole de routage ne permet le déploiement à grande échelle du réseau Ad hoc; la raison principale est le manque d'une hiérarchie. Dans cette thèse, nous proposons de découper le réseau en clusters afin de réduire la complexité de la topologie et de bâtir un réseau mis à l'échelle. Chaque cluster comprend un chef qui joue le rôle d'un point d'accès mobile. Nous pouvons ainsi imaginer une dorsale virtuelle dynamique servant d'une part à acheminer le trafic de contrôle entre les chefs d'une manière fiable et efficace et d'autre part, de limiter l'effet des changements de topologie et des conditions des noeuds dans les clusters adjacents. Le choix du noeud-chef est sujet à plusieurs critères en termes de performances (stabilité, mobilité, énergie, capacité, etc.). Ces critères constituent des métriques à considérer dans les calculs analytiques et les simulations. Pour que les clusters puissent s'adapter dynamiquement aux changements de l'environnement, nous avons proposé un mécanisme de maintenance distribuée permettant de gérer les adhésions, les handoff des noeuds et la réélection des noeuds-chefs. Parallèlement, un modèle analytique élaboré a été proposé pour faire les estimations nécessaires des paramètres de qualité de service. Ce qui nous a également permis d'intégrer un mécanisme de contrôle d'admission sur les noeuds-chefs, permettant d'éviter les congestions et toutes les perturbations intraclusters. Ceci nous a amené à balancer la charge entre les différents clusters et d'optimiser l'utilisation des ressources du réseau ^ ^ hoc. Les résultats numériques obtenus nous ont aidés à réajuster les paramètres utilisés dans la clustérisation afin de fournir une meilleure qualité de service aux applications utilisées. Finalement, pour valider nos résultats, nous avons défini quelques paramètres utiles à l'étude des performances du modèle. Les résultats des simulations ont clairement montré le niveau de stabilité des clusters en présence de mobilité et en termes de nombre de clusters formés, nombre de ré-affiliations, nombre de transitions sur les chefs, niveau de qualité de service globale, équilibrage de charge et passage à l'échelle. Nous avons aussi remarqué une meilleure connectivité et un niveau de stabilité élevé en comparant notre modèle avec un autre de la littérature et en présence de mobilité.

A dynamic IS-LM model including stocks and houses as additional assets will be analyzed in this paper. Providing also housing services, a major consumption item for most households, houses create an additional link between the monetary and the real sector of the economy. The adjustment path of output, house prices and stock prices after exogenous policy shocks will be derived within a rational expectation setup. This will show how different reaction patterns of asset prices are related to different elasticities of housing services demand. These general analytical results are contrasted with relevant empirical work, particularly Lastrapes [2002], leading to the identification of plausible elasticity ranges. The particular results for those shed new light upon the ongoing discussion about demand effects from real estate wealth and about determinants of house price fluctuations. (author's abstract)
Series: Department of Economics Working Paper Series

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A presente pesquisa foi desenvolvida no Programa de Pós-Graduação em Educação da Universidade Federal de Mato Grosso, linha de pesquisa Organização Escolar, Formação e Práticas Pedagógicas, e investigou como os jovens universitários do Curso de Direito, na cidade de Diamantino-MT, narram suas Experiências pessoais e formativas e como estas são significadas a partir da entrada no curso. A perspectiva teórico-metodológica aproxima-se da pesquisa narrativa, conforme Clandinin e Connelly (2011), Mello (2005) e outros. Os significados foram compostos a partir de um conjunto de narrativas, produzidas pelos participantes e pelo pesquisador (notas de campo e textos de campo). Da literatura tomamos como base os estudos sobre as Experiências em Larrosa Larrosa (2002, 2004), Dewey (1994, 2008); já sobre jovens: Spósito (1997, 2005), Corrochano (2013), Dayrell (2000), Abramavoy e Esteves (2007), Abramo (1997) e outros. Em relação à Educação Jurídica: Wolkmer (1997), Warat (2000,2001), Lyra Filho (1986), Souza Júnior (1984, 1987, 2008), Streck (2004). Além de Freire (1987, 2011, 2005) e Gadamer (1997, 2002). A pesquisa abrangeu seis jovens ingressantes no Curso de Direito da Universidade do Estado de Mato GrossoUNEMAT- Campus de Diamantino. Ao reconstruir as experiências vividas, foram compostos os seguintes eixos temáticos: 1- “Vidas, Tempos e Escola: Percurso Escolar dos jovens”, no qual demonstra Experiências no/do percurso escolar, isto é as percepções dos tempos de escola; 2- “Por que Direito?: Tempos, contextos de uma escolha”, aqui subdividido em duas perspectivas: “A Família: sentidos e significados, razões de uma escolha”; “Eu vou fazer direito”: entre inspirações, status e afetos, isto é quais fatores externos de algum modo motivaram a escolha pelo Curso de Bacharelado em Direito; 3- “Jovens no Curso de Direito: Vademecum, vem comigo”, trata das Experiências que os jovens ingressos estão vivenciando no curso superior, desde a questão da identidade do “ser jovem” às reflexões da Educação Jurídica ofertada. Os resultados revelaram a complexidade da vida, do nosso tempo e das escolhas, os dilemas e as dificuldades enfrentadas no cotidiano pelos participantes. Igualmente revelam que as experiências e memórias dos jovens não seguem uma trajetória linear. As narrativas demonstram que as dificuldades da vida, o apoio, sentidos e significados da família, o status social, as inspirações, desejos, possibilidades e afetos construídos a partir e além da escola permearam as narrativas, de modo que a continuidade na formação do ser jovem e universitário perpassam as histórias contadas de um ontem, do presente e projetadas no vindouro
This research was conducted at the Graduate Program in Education at the Federal University of Mato Grosso, Research School Organisation line, Training and Pedagogical Practices, and investigated the problem of how university students of the Law School in the city of Diamantino, MT , narrate their personal experiences and training and how these are meant from entering the course. The theoretical-methodological perspective approaches the narrative research as Clandinin and Connelly (2011), Mello (2005) and others. The meanings are composed from a set of accounts, produced by the investigator and the participant (field cards and field texts). Literature take as a basis the studies on the experiences in Larrosa Larrosa (2002, 2004), Dewey (1994, 2008); already on young: Spósito (1997, 2005), Corrochano (2013), Dayrell (2000), and Abramavoy Esteves (2007), Abramo (1997) and others. Regarding the Legal Education: Wolkmer (1997), Warat (2000.2001), Lyra Filho (1986), Souza Júnior (1984, 1987, 2008), Streck (2004). In Freire (1987, 2011, 2005) and Gadamer (1997, 2002). The research covered six (6) entering young at Law Course at the State University of Mato Grosso-UNEMAT- campus DiamantinoMt. By reconstructing the experiences were the following themes compounds: 1- Experiences in / of schooling, which will bring the perceptions of school days; 2- The contexts of choice at Law Course, which subdivided the role of family, sense and meaning; "I'm going to do right": between inspirations, Status and Affections, ie external factors which somehow motivated the choice of the course of Bachelor of Law; 3- Young at Law Course : Vademecum , come with me " , deals with the experiences that young people are experiencing tickets in the upper reaches , from the question of the identity of " being young " in reflection of the Legal Education offered . The results revealed the complexity of life , of our time and choices , dilemmas and difficulties faced in daily life by the participants. Also show that the experiences and memories of young people do not follow a linear path . The stories demonstrate that the difficulties of life, support , senses and family meanings , social status , inspirations , desires, possibilities and affections constructed from and beyond the school permeated the narrative , so that the continuity of the formation of the young college permeate the stories of yesterday , present and projected into the future

Lithiummanganoxid ist bekannt als preiswertes und ungiftiges Elektrodenmaterial in sekundären Lithiumionenzellen. Das Spinellsystem (Li1+xMn2-yO4-d) kristallisiert bei Zimmertemperatur in der Raumgruppe Fd-3m. Das Zyklenverhalten dieser Substanz in einer Batterie ist von großem wirtschaftlichen Interesse bei der Produktion von Batteriezellen. Es wurde gezeigt, dass zusätzlich eingebautes Lithium die Zyklenstabilität signifikant erhöht. In dieser Arbeit wurde Spinellmaterial mit unterschiedlichen Lithiumüberschußgehalten hergestellt und durch Röntgen- und Neutronenpulverbeugung charakterisiert. Die Röntgenabsorption (EXAFS) wurde zur detaillierten Betrachtung der Intercalation des Arbeitsions Lithium angewendet. Es hat sich gezeigt, das das Überschußlithium vermutlich auf kristallographische Plätze mit der Wykoff-Bezeichnung 8b eingelagert wird. Zusätzlich wurden temperaturabhängige und sauerstoffpartialdruckabhängige Messungen an den Probenmaterialen durchgeführt, um Aussagen zum Stabilitätsbereich der Phase machen zu können.

While a vast literature has been collected pointing out the role of the human capital on economic growth, a few has been said, in Economics, on the mechanism through which education directly impacts on democracy. The present dissertation proposes a novel microfoundation of this nexus based on the paramount role of education as economic growth engine and determinant of political participation. The first two works introduce elements of political psychology in order to shed lights on individual cognitive process that might favor, overall, a culture of democracy. Education is then a cognitive tool that citizens/voters can use to decode the information content of political signals and to keep rulers in charge accountable. We formally show that the entire initial distribution of education matters for a successful democracy and that the median is pivotal in the political process. Motivated by that in the last work we propose a statistical analysis of the distribution of the Italian primary school service. Primary schools tend to distribute in a complex way according to geographical features of the territory, schooling aged population density, and possible interactions between the two. Despite the school system is financed at a State level, we outline the persistence of remarkable differences not directly attributable to historical divergences among different macro-area of the country but rather between montane areas and more dynamic regions deputed to explain economic and political divergences. Chapter 2: We propose a political agency model where rent-maximizer rulers are constrained by sophisticated principals/producers that use an awareness-management model `a la B´enabou and Tirole. Sophistication is explained by educational attainments and producers are endowed with different levels of education, that increase over time with human capital investments. We allow education to be both the engine of growth and a determinant of political participation; in equilibrium, more educated societies are more able to punish politicians that, in turn, invest more in productive public goods such as infrastructure, roads or legal rules for contracts enforcement. We prove the existence of multiple steady states featuring, respectively, a sophisticated society with congruent politicians in office, and a naive society ruled by dissonant politicians. Finally, we address inequality concerns and show how, for intermediate values, inequality opposingly hits citizens and ruler and only the latter is found to better off; conversely, citizens are averse to inequality, contributing to explain, via sophisticated accountability, why most people dislike living in a society which is too unequal. Chapter 3: The paper originally attempts to explain the rise of the new wave of populism in Europe and the persistence of the Latin American populism. Such phenomena rose an unresolved political puzzle according to which populist politicians has been widely supported by the electorate while ultimately hurt the economic interests of the majorities. We address this puzzle by looking at the electorate side and, specifically, at individual citizens that are endowed with different level of political sophistication. According to the Political Psychology literature, we approximate political sophistication in terms of individual education attainments whose distribution evolve over time with human capital investments. In each period, the distribution of political sophistication within a country generates different incentive structure for the incumbent that accordingly optimally decide whether to be a populist or a responsible type whereas between countries might determine completely different equilibria in the long run, one with populist politicians and one ruled by responsible ones. I argue that rent-maximizer politicians have the chance to behave in a populist fashion when a naive electorate fail in keeping rulers politically accountable. Despite citizens are politically committed to responsible economic policy, naive voters are basically unaware of the politicians intentions providing to the latter opportunities for the manipulation of the economy and the electoral outcome. Populist rulers carry out inefficient investment with the only intent to induce a mean-increasing spread in future distributions of human capital so as to increase electoral consensus based on a naive electorate and to maximize tax revenues based on a few of rich. Chapter 4: We characterize the statistical law according to which Italian primary school-size distributes. We find that the schoolsize can be approximated by a log-normal distribution, with a fat lower tail that collects a large number of very small schools. The upper tail of the school-size distribution decreases exponentially and the growth rates are distributed with a Laplace PDF. These distributions are similar to those observed for firms and are consistent with a Bose-Einstein preferential attachment process. The body of the distribution features a bimodal shape suggesting some source of heterogeneity in the school organization that we uncover by an indepth analysis of the relation between schools-size and citysize. We propose a novel cluster methodology and a new spatial interaction approach among schools which outline the variety of policies implemented in Italy. Different regional policies are also discussed shedding lights on the relation between policy and geographical features.

Internet was originally designed to offer best-effort data transport over a wired network with end machines using a layered network protocol stack to provide mainly reliability and quality of service for end user applications. However, the excess of wireless end devices and the demand for sophisticated mobile multimedia applications forces the networking research community to think about new design methodologies. In fact, this kind of applications is characterized not only by a large amount of required data-rate, but also by a significant variability of the data-rate over time due to the dynamics of scenes, when state of the art of video encoding techniques are considered and are especially challenging due to the time varying transmission characteristics of the wireless channel and the dynamic quality of service (QoS) requirements of the application (e.g., prioritized delivery of important units, variable bit rate and variable tolerance vs. bit or packet errors). One of the focused issues in the improvement of multimedia transmission quality is to combine the characteristics of the video applications and the wireless networks. Traditional approaches, in which the characteristics of the video application and wireless networks are isolated, would induce the resources not being optimized. Cross-layer design also known as Cross-layering is a new paradigm in network design that not only takes the dependencies and interactions among the layers of the Open System Interface (OSI) structure into account, but also attains a global optimization of the layer-specific parameters. However, most existing cross-layer designs for Quality of Service (QoS) provisioning in multimedia communications are mainly either aiming at improving throughput of the network or reducing power consumption, yet regardless of the end-toend qualities of multimedia transmission. Therefore, the application-driven cross-layer design over various multimedia communication systems is needed to be extensively investigated. Following the extensive study of performance bounds and limitations of the sate of the art in this research area, we argue that performance improvement of multimedia applications over wireless access networks can be achieved through considering the application-specific requirements also called service- or context-awareness. Indeed, we designed two cross-layer design schemes called CORREC and SARC for Wi-Fi and 3G networks respectively. We show that further performance improvement can be achieved by tuning ARQ and HARQ strength respectively based on the application requirements and protocol stack operation on the mobile terminal. In the other hand, the Transmission Control Protocol (TCP) which accounts for over 95% of Internet traffic shows poor performance in wireless domain. We propose a novel approach aiming at TCP performance improvement in WLAN networks. It consists in proposing a joint optimization of ARQ schemes operating at the transport and link layers using a cross-layer approach called ARQ proxy for Wi-Fi networks.

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
As leis existentes em Lv 18 e Lv 20 tratam de relações sexuais consideradas ilícitas, com destaque especial para relações de natureza incestuosa. Tema que está presente, de forma semelhante, nos parágrafos 154 a 158 do Código de Hammurabi. À diferença do segundo, os primeiros textos não proíbem explicitamente a relação incestuosa entre pai e filha(s). A presente Tese propõe analisar cada um dos dois corpora legislativos em seus contextos sócioliterários e compará-los na tentativa de explicar o silêncio existente no Levítico a respeito do incesto. Além disso, a Tese discute o alcance normativo das leis bíblicas à semelhança da discussão teórica existente sobre o tema no que tange ao Direito cuneiforme.
The existing laws in Lv 18 and Lv 20 are about illicit sexual intercourse, with special focus on relationships of incestuous nature. The issue is also present in paragraphs 154 to 158 of the Hammurabi Code. Apart from the second, the first texts do not explicitly forbid incestuous intercourse between father and daughter(s). The present thesis proposes both the analysis of each legislative corpus in their social and literary contexts and their comparison as a way to explain the existing silence on incest in the Leviticus. Besides, this paper discusses the normative reach of biblical laws considering the theoretical discussion about the issue taking the cuneiform Law into consideration.

In this project we have carried out a computer simulation for the studyof electronic structure of the bulk silicon and geometric structure of $SiO_2$ cluster. We found the charge density and energy band gap for the bulk silicon. The geometric optimization of the cluster $SiO_2 $was undertaken in this project.Finally we supply our results and state the future works in this field.

Two sets of parameters and potential energy surfaces for a single CO$\sb2$ molecule adsorbed on the (001) face of a uniform semi-infinite crystal of NaCl were developed and tested using the Steepest Descent method. When the CO$\sb2$ molecule attains the absolute minimum of the potential energy it was found, for both parameter sets, to lie parallel to the surface at height z = 2.5 A above the connection line of two adjacent Na$\sp+$ ions (along the $\langle 110\rangle$ direction) at 1.994 A from Na$\sp+$ (C to Na$\sp+$); i.e. the carbon atom is directly above the midpoint between two sodium ions. The values of the potential energy were found to be E$\sb\min = {-}7.643$ kcal/mol and E$\sb\min = {-}8.000$ kcal/mol for parameters set I and set II respectively. Saddle points in the potential energy surfaces were found to exist above the connection line between Na$\sp+$ and Cl$\sp-$ (the $\langle 100\rangle$ direction). The position of this point correspond to a lateral sodium to carbon distance of 0.92 A and a carbon height of z = 2.95A above the surface for parameter set I. At this position the molecule is tilted by an angle of $35\sp\circ$ from surface $(55\sp\circ$ from the surface normal). The potential energy at this point was found to be E$\sb{\rm sad} = {-}5.723$ kcal/mol which yielded an estimated diffusion barrier energy of E$\sb{\rm diff} = 1.918$ kcal/mol. The parameter set II was examined the similar results was obtained. The single molecule surface potential which was developed was then used within the Metropolis Monte Carlo method to examine monolayer, bilayer and trilayer configurations of CO$\sb2$ on an NaCl(001) surface. (Abstract shortened by UMI.)

Le fjord du Saguenay constitue le plus important tributaire de l'estuaire du St-Laurent. Il abrite une faune ichtyologique diversifiée constituée d'espèces dulcicoies, diadromes et marines. Au cours des 20 dernières années, la pêche sportive hivernale sur le Saguenay a connu une popularité croissante devenant un attrait touristique important pour la région du Saguenay. L'espèce la plus exploitée par cette industrie, en terme de nombre de captures, est l'éperîan arc-en-ciel (Osmerus mordax). Cette espèce constitue une proie de prédilection pour bon nombre d'espèces de poisson, notamment des poissons de fond, également exploités lors de la pêche sportive hivernale. Avant les présents travaux, aucune étude n'avait été faite sur le recrutement larvaire de l'éperîan arc-en-ciel dans le fjord du Saguenay. Face à ce constat, on a cherché à mieux définir les facteurs biotiques et abiotiques ayant une influence sur le recrutement larvaire de Péperlan arc-en-ciel, qui constitue une population propre au fjord du Saguenay. Deux campagnes d'échantillonnage terrain ont eu lieu à l'été 2004 et 2005. Six et cinq missions ont été effectuées respectivement en 2004 et 2005. Lors de ces missions, sept transects ont été échantillonnés sur trois stations pour un total de 21 stations. L'ichtyoplancton a été échantillonné avec un filet bongo et un chalut Tucker de 500 um. Le zooplancton a été récolté, à l'aide d'un filet de 158 um, ainsi que les paramètres physico-chimiques, à l'aide d'une sonde CTD, ont également été prélevés. L'ensemble des larves de poisson ont été dénombrées et identifiées et les otolithes sagittas ont été prélevés sur un total de 576 larves d'éperlan arc-en-ciel. Des calculs de densité, de croissance récente et de trajectoire de croissance ont été faits pour les larves des deux années. Les résultats de cette étude ont démontré que le recrutement larvaire de l'éperlan arc-en-ciel serait principalement limité par deux facteurs. Premièrement, les fluctuations du débit d'eau douce de la rivière Saguenay auraient une influence sur la répartition des larves dans le fjord, les années de fort débit étant défavorables. Deuxièmement, la croissance larvaire de l'éperîan arc-en-ciel serait favorisée par de fortes concentrations du calanoïde Eurytemora affinis. Ces deux facteurs seraient intimement liés puisque les forts débits contribueraient à éloigner les larves d'éperlan des zones à forte concentration de E. affinis dont la Baie des Ha! Ha!. Par ailleurs, les conditions très variables dans le fjord du Saguenay auraient favorisé l'extension de la période d'éclosion qui s'échelonne sur près de deux mois.

Metals have found wide applications in the field of implant fabrication for the replacement of human hard tissues. Titanium being biocompatible, possessing the high strength to weight ratio, having low density, low modulus and showing ease of fabrication is the new implant material. This study gives the microstructural characterization of conventional rolled titanium (Ti) deformed by cold rolling. The Ti samples were then characterized by optical microscopy, X-ray diffraction, Vickers hardness measurements, contact angle measurements and tensile test. In addition, in vitro bioactivity of the Ti samples was carried out in simulated body fluid (SBF) for 28 days. Protein adsorption was also studied using bovine serum albumin (BSA). Rolling has induced an increase in hardness, protein adsorption and tensile properties. X-ray powder diffraction (XRD) analysis shows the diffraction pattern of the samples corresponding to titanium along with those that correspond to apatite after bioactivity study in SBF. The abovementioned properties are basic pre-requisites for bone-implant applications. Hence, from this study it can be concluded that the rolled Ti is a suitable biomaterial for biomedical applications.

Recently room temperature ionic liquids (ILs); called green solvents are emerging as promising candidates to capture due to their wide liquid range, low melting point, negligible vapor pressure, high solubility and reasonable thermal stability. However, these solvents, suffer from a major disadvantage of high viscosities in their unreacted state, which makes them very difficult to handle and transport in an industrial scenario. To make up for this, combining RTILs with conventional solvents like alkanolamines have been proposed.Again, owing to the huge number of possible combinations between cations and anions and blends of the resulted ILS/RTILs with alkanolamines, a solvent screening procedure became essential in narrowing down the solvents/blended solvents with the desired properties. In view of this, various thermophysical and physicochemical properties intended for CO2 absorption were predicted for the ionic liquids as well as their alkanolamine blends using the computational chemistry software “cosmotherm”.Various properties like density, heat capacities, viscosities, conductivity, melting point etc were studied by changing the substituent cation or anion of ILS/RTILs and their combinations with alkanolamines as well.On comparison of the predicted properties, it has been noticed that the anions TF2N and PF6 exhibits the most desirable properties in combination with the solvents MEA, DEA and PE.The screened solvents in this study might be proving their worth on experimental verification.

У дисертації здійснене теоретичне узагальнення і запропоновані практичні напрями розв’язання наукової проблеми – підвищення ефективності діагностики і інтенсивної терапії синдрому поліорганной недостатності у новонароджених. На основі запропонованої концепції морфологічного субстрату обґрунтований вибір критеріїв діагностики цього синдрому, встановлені фонові чинники і фактори, які безпосередньо впливають на його формування, визначені особливості клінічного перебігу. Розроблений спосіб визначення ризику розвитку даного синдрому у новонароджених. Показано, що патогенез синдрому поліорганної недостатності у новонароджених реалізується на різних рівнях біологічної організації. Доведена роль в його формуванні експресії і поліморфізму гену Toll-like рецепторів 2 типу, порушення клітинного енергозабезпечення і продукції інтерферону–α. Запропонована методика оптимізації інтенсивної терапії даного синдрому екзогенним інгаляційним введенням інтерферону–α і інфузією сукцинату натрію.

In this thesis we study dilepton production in Pb-Au collisions at 158 GeV/c per nucleon measured with the Cherenkov Ring Electron Spectrometer (CERES) at the Super Proton Synchrotron (SPS) at CERN. The data taken in the year 2000 represent the first CERES runs with the fully operational Time Projection Chamber (TPC). The upgrade of the spectrometer with this powerful tracking device allows to realize a new approach for particle identification with the Ring Imaging Cherenkov (RICH) detector. We present the development and optimization of track-based ring reconstruction methods which allow to identify both electrons and pions at momenta above the Cherenkov threshold. To compare the performance of different methods, the reconstruction is applied to the CERES data. This allows to determine experimentally, for the first time, the CERES RICH efficiency and background rejection power. The new particle identification is used for low-mass dielectron reconstruction. Significant improvements in the simulation of the detector allow to evaluate the electron pair reconstruction efficiency with high accuracy and to study the origin of electron pair combinatorial background. The results motivate an extension of the TPC tracking, to improve the reconstruction efficiency for low-momentum tracks, and allow better identification of electron background. Our results corroborate the previous CERES findings of an enhancement of electron pairs over the hadronic cocktail in the invariant mass region m > 0.2 GeV. Comparison to previous analyses of the same data shows good consistency and supports our estimate of the systematic uncertainties of the electron analysis. Our results supply evidence for a modification of the spectral function of the rho meson in the hot and dense medium and strongly support baryon-induced interactions at the origin of the effect. Furthermore, we present in this work the first direct measurements of transition radiation (TR) spectra in irregular radiators, carried out with prototypes of the ALICE (A Large Ion Collider Experiment) transition radiation detector (TRD). The measurements are confronted with calculations for regular radiators. The TR yield and the shape of the spectral distributions for different electron momenta are well described by the simulations.

A leitura tem um papel de extrema importância no desenvolvimento da personalidade das crianças; em consequência, a literatura infantil e a forma como é elaborada, incluindo o texto, narrativo ou poético, e as ilustrações, são fundamentais não apenas para o desenvolvimentos da personalidade infantil, mas também dos níveis de literacia das crianças. Neste sentido, as Bibliotecas Públicas podem exercer uma actuação de grande influência, através dos serviços que prestam no âmbito da promoção da leitura e da difusão da literatura para a infância. Aqui incluem-se as bibliotecas itenerantes, que fazem chegar a informação onde é mais difícil, pelas mais variadas razões. O serviço de bibliotecas itenerantes, que tem origem no século XIX, foi em Portugal desenvolvido pela Fundação Calouste Gulbenkian entre o início dos anos 50 do século passado e o início da última década do século XX, e permanece vivo nos dias de hoje, através de muitas bibliotecas integradas na rede Nacional de Bibliotecas Públicas. O presente trabalho incide sobre a temática das bibliotecas itenerantes, partindo de uuma revisão da literatura que abrange quatro temas fundamentais para alicerçar o estudo empírico desenvolvido, a saber, (1) a importância da leitura e escrita na criança, (2) os serviços da Biblioteca Pública no apoio à aprendizagem, (3) a história das Bibliotecas Públicas em Portugal e (4) a História da Biblioteca Itinerante no concelho de Espinho. O principal objectivo da investigação foi avaliar, nas escolas do 1.ºciclo do concelho de Espinho (Esmojães, Guetim, Bouça, Lomba, Quinta da Seara, Espinho 3, Anta 1, Anta 2, Anta 3, Monte, Calvário e Marinha), o serviço prestado pela carrinha biblioitenerante, através das opiniões dos alunos do 4.º ano. Para a sua realização elaborámos um inquérito por questionário, cujos resultados nos permitiram enquadrar os alunos com a leitura, a biblioteca e o serviço itenenrante, avaliar a influência das visitas da Biblioitenerante e finalmente obter informções sobre os gostos dos alunos em questão, no âmbito dos temas preferidos para a leitura e para a realização de actividades de animação. Como era expectável, existem diferenças nos resultados obtidos, considerando as escolas e a sua localização geográfica nas diversas freguesias do concelho, tendo em conta as características socioeconómicas e culturais das mesmas. Reading has an extremely important role in personality development of children; as a result of that, children's literature and how it is drafted, including the text, narrative or poetic, and the illustrations, are not only fundamental to the development of the child's personality, but also to the literacy levels of children. In this sense, public libraries may have an action of great influence, through the services they provide within the reading promotion and dissemination of literature for children. This includes whether the mobile libraries, which do get the information where it is more difficult, for various reasons. The mobile library service, which has origins in the nineteenth century, was developed in Portugal by the Calouste Gulbenkian Foundation between the early fifties of last century and the beginning of the last decade of the twentieth century, and remains alive nowadays, through many libraries participating in the National Network of Public Libraries. This work focuses on the theme of mobile libraries, based on a literature review covering four key themes to underpin the empirical study, namely, (1) the importance of reading and writing in children (2) the services of Public Library in the learning support, (3) the history of Public Libraries in Portugal and (4) the history of Mobile Library in the city of Espinho. The main aim of the research was to evaluate the schools of the first grade of the city of Espinho (Esmojães, Guetim, Bouça, Lomba, Quinta da Seara, Espinho 3, Anta 1, Anta 2, Anta 3, Monte, Calvário e Marinha), the service provided by the Mobile Library through the students' opinions of the fourth year. For its realization we drew up a questionnaire survey, whose results have allowed us to fit students with reading, library and roaming, assess the quality of available resources (human and documentary), analyze the influence of the visits made by the mobile library and finally get information about the tastes of the pupils concerned, under the favorite subjects for reading and for the conduct of entertainment activities. As expected, there are differences in the results obtained, considering the schools and its geographic location in the different communes of the city, having in consideration its socioeconomically characteristics as well as cultural.
Orientação: Professora Doutora Isabel Vaz de Freitas.

In this paper, the low-mass electron pair production in 158 AGeV/c Pb-Au collisions is investigated with the Cherenkov Ring Electron Spectrometer (CERES) at the Super Proton Synchrotron accelerator (SPS) at CERN. The main goal is to search for modifications of hadron properties in hot and dense nuclear matter. The presented re-analysis of the 1996 data set is focused on a detailed study of the combinatorial-background subtraction by means of the mixed-event technique. The results confirm previous findings of CERES. The dielectron production in the mass range of 0.25 < mee < 2 GeV/c2 is enhanced by a factor of 3.0±1.3(stat.)±1.2(syst.) over the expectation from neutral meson decays. The data is compared to transport model calculations and seem to favor the version including in-medium effects. Furthermore, the development of a new technology to manufacture ultralightweight mirrors for Ring Imaging Cherenkov detectors (RICH) is described. Replacement of the RICH-2 glass mirror by a mirror almost transparent to electrons would considerably improve the performance of the upgraded CERES detector system including a radial Time Projection Chamber (TPC).

This thesis presents a two-particle correlation analysis of the fully calibrated high statistics CERES Pb+Au collision data at the top SPS energy, with the emphasis on the pion-proton correlations and the event-plane dependence of the correlation radii. CERES is a dilepton spectrometer at CERN SPS. After the upgrade, which improved the momentum resolution and extended the detector capabilities to hadrons, CERES collected 30 million Pb+Au events at 158 AGeV in the year 2000. A previous Hanbury-Brown-Twiss (HBT) analysis of pion pairs in a subset of these data, together with the results obtained at other beam energies, lead to a new freeze-out criterion (Phys. Rev. Lett. 90, 022301 (2003)). In this work, the detailed transverse momentum and event-plane dependence of the pion correlation radii, as well as the pion-proton correlations, are discussed in the framework of the blast wave model of the expanding fireball. Furthermore, development of an electron drift velocity gas monitor for the ALICE TPC sub-detector is presented. The new method of the gas composition monitoring is based on the simultaneous measurement of the electron drift velocity and the gas gain and is sensitive to even small variations of the gas mixture composition. Several modifications of the apparatus were performed resulting in the final drift velocity resolution of 0.3 permille.

Strangeness production in ultra-relativistic nucleus-nucleus collisions is one of the most important probes of hot and dense nuclear matter. Yields and spectra of hadrons carrying strangeness are being studied over a broad range of energies. A remarkable result is that the yields of strange hadrons appear to be in chemical equilibrium in nucleus-nucleus collisions in contrast to observations in elementary collisions. The first part of this thesis is dedicated to the reconstruction of charged kaons in central Pb+Au collisions at the top SPS energy with the CERES pectrometer. The analysis scheme is based on the reconstruction of the decay of charged kaons in three charged pions. This approach is, with the exception of the pioneering work of the NA35 experiment, applied for the first time in ultra relativistic heavy ion collisions for the charged kaons reconstruction. In total 102k K+ and 57k K- were reconstructed in 24.3M central Pb+Au collisions. The mid-rapidity yields are 31.8 for K+ and 19.3 for the K-. These results together with K-/K+, K+/pi+ and K-/pi- ratios are compared with the existing results from NA49, NA44, NA57 and CERES measurements as well as with thermal model predictions. The second part of this thesis is devoted to the study of fast Transition Radiation Detectors (TRD). Results of a stand alone simulation study of the performance of a TRD detector with gas chamber read out in terms of electron-pion separation as a function of the main parameters of the radiator and readout detector are shown. The optimization of the detector was based on the requirements of the CBM experiment. A comparison of simulated energy deposition to experimental data is presented.

A critical and in-depth discussion of the powers of the labour court to review arbitration awards of the Commission for Conciliation, Mediation and Arbitration, the application of the author's findings relating to common-law, legislation and case law and a critical analysis thereof. Special reference is made to the provisions of sections 145 and 158(1)(g) of the Labour Relations Act 66 of 1995 including, in particular, the alternative application thereof in practice and scope for improvement in order to address potential prejudice to parties occasioned by the compulsory nature of (certain) dispute resolutions. This thesis incorporates a comparative study of the British and German labour law systems with reference to the relevant appeal and/or review procedures (as applied in their tribunals/courts), together with a discussion and application of certain other provisions relevant to South Africa labour law.
Jurisprudence
LL.M

La psicologia del lavoro e delle organizzazioni si focalizzano soprattutto sui fattori che favoriscono un funzionamento lavorativo efficace. Tuttavia in ambito lavorativo si trovano anche azioni inefficaci o perfino distruttive. Il Comportamento Lavorativo Controproduttivo (Counterproductive Work Behavior, CWB) consiste di atti volontari che apportano danni ad un’organizzazione o alle persone ad essa collegate. Qui viene presentato il modello di Spector e Fox (2005) come risultato congiunto delle condizioni stressanti sul lavoro e delle caratteristiche di personalità. Viene presentata infine un piccolo studio empirico su 54 persone, che è stato poi incluso in una ricerca molto più vasta condotta dalla Facoltà di Psicologia 2 dell'Università La Sapienza di Roma.