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  • 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.
21

Hvězdný vítr a ztráty momentu hybnosti dvojhvězdy / Angular momentum loss from binary systems due to stellar winds

Hubová, Dominika January 2021 (has links)
Massive binary evolution is crucial for our understanding of many pheno- mena in the Universe, such as high-mass X-ray binaries or the formation of compact systems emitting gravitational waves. In this work, we study the loss of angular momentum from binary systems caused by radiation driven stellar winds, which are characteristic for hot, massive stars. Calculating numerically ballistic trajectories of particles ejected from the binary surface, we establish the average specific angular momentum loss as a function of the system's mass ratio for binaries in semidetached and contact stages. We initiate the outflow on the Roche lobes or even on further equipotentials of the Roche potential in case of over-contact systems. Moreover, we implement two models of the radiation driven wind. Firstly, we eject particles from the surface of the binary with a non-zero initial velocity, but we then let them evolve only under the influence of the system's gravity. In the second model, we develop a simple method for computing the radiative acceleration due to the radiation pressure from the bi- nary surface. Our results can be used in further calculations of the evolution of massive binary systems.
22

Strain and Volume Loss in a Second Order Buckle Fold, Central Appalachian Valley and Ridge, U.S.A.

Markley, Michelle J. January 1990 (has links)
No description available.
23

Essays in Applied Microeconomics, Health Economics and Genomics

Upegui, Angie 16 June 2021 (has links)
Durante el ciclo de la vida, los individuos se ven expuestos a distintos factores tanto exógenos como endógenos, con diversas consecuencias sobre el comportamiento y el bienestar de los mismos. Entender la forma en que dichos factores afectan desenlaces de interés tanto a nivel individual como agregado, permite formular políticas públicas que mitiguen o potencien los efectos encontrados. En esta tesis analizo como factores socio-económicos, ambientales y genéticos afectan las decisiones de consumo y los niveles de salud de los individuos. En el primer capítulo de esta tesis, evalúo el efecto de una asignación gratuita de agua otorgada a hogares de bajos niveles socio-económicos en la ciudad de Bogotá (Colombia). Específicamente, evalúo el efecto de la asignación sobre las decisiones de consumo de agua de los individuos, encontrando que gracias a la intervención, los hogares incrementan su consumo de agua, al tiempo que experimentan una disminución en la factura del agua. Este resultado sugiere que la asignación funciona como una transferencia en efectivo. Adicionalmente, encuentro un incremento en el porcentaje de hogares que poseen un lavamanos; de esta forma el subsidio genera un incremento en el consumo de bienes durables relacionados con el consumo de agua. Finalmente, encuentro que entre la población más vulnerable, hay una disminución en la prevalencia de diarrea en menores de cinco años. En el segundo capítulo, analizo como la asociación entre variantes genéticas relacionadas con la obesidad y el índice de masa corporal (IMC) varía a lo largo del ciclo de la vida en varias cohortes poblacionales en Estados Unidos. Para tal fin empleo puntuaciones poligénicas, índices que resumen el riesgo genético de las personas hacia un elevado IMC. Encuentro que el efecto de las puntuaciones poligénicas del IMC sobre el IMC aumenta significativamente a medida que los adolescentes pasan a la edad adulta. Sin embargo, este no es el caso de las personas mayores de 55 años, cuya influencia genética en el IMC es notablemente estable a medida que avanzan hacia la vejez. Finalmente, en el último capítulo, evalúo el efecto que tienen los niveles de lluvia sobre medidas objetivas de salud mental en un país en vías de desarrollo. Usando un modelo de efectos y datos colombianos, encuentro que incrementos en los niveles de lluvia generan incrementos en el número de intentos de suicidios, en el número de personas tratadas por problemas de salud relacionados con el estrés y en el número de personas tratadas por depresión. A su vez encuentro una relación positiva entre niveles de lluvia y desempleo. Entre la población trabajadora, encuentro que incrementos en los niveles de lluvia únicamente afecta a los trabajadores del sector formal. Este resultado sugiere que los trabajadores del sector informal continúan trabajando aún bajo condiciones climáticas adversas.
24

Morfologické zmeny hipokampu v tetanotoxínovom modeli temporálnej epilepsie / Morphological changes of the hippocampus in tetanus toxin model of temporal lobe epilepsy

Demeterová, Ľubica January 2015 (has links)
Temporal lobe epilepsy is the most common form of epilepsy and hippocampal sclerosis represents the main underlying structural abnormity. Approximately 20% of TLE cases are non- lesional due to absence of any obvious epileptogenic lesion and tetanus toxin model is traditionally considered as a model of non-lesional temporal lobe epilepsy. The main aim of this study was to evaluate the presence of the cell damage and to determine its spatiotemporal profile. Tetanus toxin was stereotaxically injected into CA3 subregion of dorsal hippocampus in adult male Wistar rats. Brain tissue was extracted 4, 8 and 16 days following the surgery. Postfixed brains were sectioned to 50 µm slices and labeled using Nissl's and FluoroJade B staining (FJB). Hippocampal sclerosis was present only in animals from D16 group, however, it was localized mainly in contralateral CA1 area. Additional finding was decreased Nissl's staining in contralateral hippocampus which corresponded with the presence of FJB positive neurons. In animals from group D8, we have identified presence of FJB positive neurons predominantly in ipsilateral hippocampus. In D4 animals, cellular degeneration was absent. To examine the non- lesional nature of tetanus toxin model, we have performed blind study, when Nissl's staining were reviewed...
25

Generic Distractions and Strata of Hilbert Schemes Defined by the Castelnuovo-Mumford Regularity

Anna-Rose G Wolff (13166886) 28 July 2022 (has links)
<p>Consider the standard graded polynomial ring in $n$ variables over a field $k$ and fix the Hilbert function of a homogeneous ideal. In the nineties Bigatti, Hulett, and Pardue showed that the Hilbert scheme consisting of all the homogeneous ideals with such a Hilbert function contains an extremal point which simultaneously maximizes all the graded Betti numbers. Such a point is the unique lexsegment ideal associated to the fixed Hilbert function.</p> <p> For such a scheme, we consider the individual strata defined by all ideals with Castelnuovo-Mumford regularity bounded above by <em>m</em>. In 1997 Mall showed that when <em>k </em>is of characteristic 0 there exists an ideal in each nonempty strata with maximal possible Betti numbers among the ideals of the strata. In chapter 4 of this thesis we provide a new construction of Mall's ideal, extend the result to fields of any characteristic, and show that these ideals have other extremal properties. For example, Mall's ideals satisfy an equation similar to Green's hyperplane section theorem.</p> <p> The key technical component needed to extend the results of Mall is discussed in Chapter 3. This component is the construction of a new invariant called the distraction-generic initial ideal. Given a homogeneous ideal <em>I C S</em> we construct the associated distraction-generic initial ideal, D-gin<sub><</sub> (<em>I</em>), by iteratively computing initial ideals and general distractions. The result is a monomial ideal that is strongly stable in any characteristic and which has many properties analogous to the generic initial ideal of <em>I</em>.</p>
26

Public Policy and Gentrification in the Grandview Woodland Neighbourhood of Vancouver, B.C.

Kasman, Paul 14 December 2015 (has links)
The Grandview Woodland local area of Vancouver, British Columbia, is an area in transition. Retail, demographic, residential occupancy, and changes to built structures indicate that gentrification has escalated in the past seven years. Long standing impediments to gentrification, including industrial manufacturing, social housing, and crime, are not deterring change in this area to the extent they once did. This thesis examines how public policy has affected these changes in Grandview Woodland. Public policies embodied in laws and regulations have the capacity to either encourage or dissuade gentrification; however, other variables also influence gentrification making it difficult to determine the importance and influence of public policy in the process. This thesis uses semi-structured interviews and a document review in a case study of Grandview Woodland, to gain a better understanding of how public policies can influence gentrification in a local area where gentrification was previously impeded. The findings from this study suggest that public policies can have a substantial, but not autonomous, effect on gentrification in such an area. In Grandview Woodland, policy makers facilitate gentrification through city-wide and province-wide policies, including zoning changes, the Strata Title Act, and the Residential Tenancy Act. While these public policies have streamlined the advance of gentrification in Grandview Woodland, the catalysts for gentrification are the wider national trend of increased popularity of inner-city living, and the middle class moving eastwards in search of affordable homes in response to the massive property value increases in Vancouver’s West Side. / Graduate / 0617 / 0615 / 0999 / p.b.kasman@gmail.com
27

Vliv angličtiny na jazykovou politiku a plánování ve Švédsku / The impact of English on language policy and planning in Sweden

Šišovská, Jana January 2015 (has links)
This sociolinguistic study deals with the impact of English on language policy and planning in Sweden. The analysis is based on the principles of the language management theory. The first part is devoted to the discourse of relations between Swedish and other languages in the country, mostly dealing with Swedish as an endangered language due to the extensive use of English causing domain loss. The recently adopted language law is presented as a reaction to this development, giving an official status to Swedish as the main language of the country. According to this, it should be possible to use Swedish within all domains of language use. The problems of domain loss and the risk of diglossia are demonstrated on the example of the domains of higher education and science in the second part. The principles of the Language law are confronted with the need of increased use of English and the strategy of parallel language use suggested as a possible solution. A very valuable source of information for the analysis also are two interviews with the members of the Swedish language council, the institution responsible for implementation of the Language law as well as for observation of the general language situation. Keywords: Swedish, language policy and planning, language management, domain loss, parallel...
28

Etude de systèmes et scénarios électronucléaires double strate de transmutation des actinides mineurs en ADS / Study of nuclear energy systems and double strata scenarios for minor actinides transmutation in ADS

Clavel, Jean-Baptiste 30 November 2012 (has links)
La loi française du 28 juin 2006, sur la gestion des déchets radioactifs, demande une évaluation pour définir la future stratégie industrielle. L’étude présentée ici, concerne plus spécifiquement l’axe de recherche sur la transmutation des actinides mineurs. Dans ce but, un concept d’ADS (Accelerator DrivenSystem) de haute puissance a été développé à SUBATECH. Dans ce réacteur sous-critique, un faisceau de protons de 1 GeV alimente trois cibles de spallation de plomb-bismuth. L’ADS MUST (MUltipleSpallation Target) peut ainsi atteindre une puissance thermique de plus de 1 GW avec une densité de puissance élevée. Une méthode de dimensionnement de ces réacteurs a été développée et appliquée pour différents scénarios double strate. Dans ces scénarios, des réacteurs électrogènes de type SFR (Sodium Fast Reactors) ou REP (Réacteurs à Eau Pressurisée) produisent des actinides mineurs destinés à être transmutés en ADS. Dans chaque cœur, un multi-recyclage du plutonium est réalisé et dans les réacteurs sous-critiques les éléments à transmuter le sont également. Pour limiter la réactivité du cœur et améliorer la conductivité thermique, le combustible contenant les actinides mineurs est mélangé à une matrice inerte de MgO. Des filières, avec des ADS à caloporteurs plomb et sodium, ont été étudiées pour différentes durées d’irradiation, et deux stratégies de transmutation : soit l’ensemble des actinides mineurs, soit seulement l’américium est incinéré. Le dimensionnement des ADS MUST de chaque filière et de leur combustible à l’équilibre est présenté dans cette thèse. Puis l’évolution du combustible et du coefficient de multiplication, sur un cycle, est réalisée et analysée. La radiotoxicité et la puissance thermique des déchets produits sont ensuite comparées. Enfin, l’étude de scénarios double strate est effectué afin d’analyser les inventaires d’actinides mineurs et de plutonium en cycle, ainsi que les déchets produits en fonction de la stratégie de transmutation adoptées et de l’évolution de la première strate. / The French law of 28th June 2006 regarding advanced nuclear waste management requires a scientific assessment to define future industrial strategies. The present PhD thesis was carried in this framework and concerns specifically the research axis of minoractinides transmutation. A high power Accelerator Driven System (ADS) concept is developed at SUBATECH for this purpose. A 1 GeV proton beam feeds three liquid lead-bismuth spallation targets. The MUltiple Spallation Target (MUST) ADS reaches the thermal powers up to 1 GW with a high specific power. A nuclear reactor dimensioning method has been developed and applied to different double strata scenarios. In these scenarios, SFR (Sodium FastReactors) or PWR (Pressurized Water Reactors) power reactors produce minor actinides that will be transmuted into ADS. In each core (SFR and ADS), the plutonium multi-reprocessing strategy is performed while ADS subcritical core also multi-reprocesses minor actinides. To limit the core reactivity and improve the fuel thermal conductivity, the minor actinides fuel is mixed with MgO inert matrix. Nuclear branches with lead and sodium coolants for the ADS, have been studied for different irradiation times and two transmutation strategies have been assessed : whether whole minor actinides, whether americium only is tranmuted. The thesis presents precisely the MUST ADS design methodology and the calculations to get a fuel composition at equilibrium. Then a one cycle evolution is performed and analysed for the fuel and the multiplication factor. Radiotoxicity and thermal power of the waste produced are then compared. Finally, the study of double strata scenarios is performed to analyse the plutonium and minor actinides inventories in cycle and also the waste produced according to the transmutation strategies applied and the first stratum evolution.
29

L'adoption de la nouveauté par les consommateurs. Séquence et développement dans le cas de la Chine contemporaine / The adoption of novelty by consumers. Sequence and development in the case of contemporary China

Faullimmel, Matthieu 15 January 2018 (has links)
Cette recherche vise à expliquer et comprendre le déroulement de l'adoption de la nouveauté par les consommateurs, de l'action de quelques-uns à l'adoption collective, voire l'institutionnalisation d'un marché de la nouveauté. Les historiens établissent un lien fort entre le développement de l'adoption de la nouveauté et celui de nouvelles strates intermédiaires. La Chine des années 2010 offre un cas d'étude idéal. La comparaison historique permet de formuler l'hypothèse de dynamiques statutaires différentes en Europe et en Chine, et d'une régulation différente des statuts. Une matrice contextuelle expliquant l'adoption est construite et appliquée aux modèles de seuils pour définir des séquences typiques conduisant à l'adoption collective de la nouveauté. Plusieurs réseaux de jeunes adoptants de nouvelles technologies diplômés du supérieur sont suivis entre 2010 et 2015 au moyen d'entretiens individuels approfondis (video-chat, échanges informels et recoupement de sources digitales). L'analyse montre l'existence de chaînes d'adoption, et met en lumière le rôle de relayeurs de la nouveauté. Elle permet de décrire deux séquences typiques de passage à l'adoption collective en restituant la significativité des contextes dans lesquels adoptant et relayeur s'apparient. Les récits d'adoption sont resitués dans le contexte de l'évolutions des carrières professionnelles et conjugales. Ils permettent de comprendre le lien entre adoption et nouvelles strates intermédiaires. Ces dernières sont porteuses de différentes visions de la nouveauté marchande et de la modernisation. Le contexte de réformes et de transition chinois d'après 1978 apparaît comme un lieu favorable à cette double configuration. / The purpose of this research is to explain and understand the adoption of novelty by consumers as a dynamic phenomenon, from its initial stage as an individual action to the collective one and finally as a novelty market. Historical studies highlight the link between the development of novelty adoption and the one of intermediate social strata. Historical comparison allows to formulate hypothesis: different status dynamics and State regulation of status. A contextual matrix is built to define contexts explaining adoption. Inspired by threshold models, typical sequences of collective adoption can be defined. Several networks of young adopters who recently graduated are identified and tracked between 2010 and 2010 (through video-chat in depth individual interviews, informal message exchange and online research). The analysis highlights the existence of novelty chains, and the role of novelty passers. It allows to describe two typical sequences of the collective adoption of novelty and restore the significance of contexts in which adopters and passers match together. Adoption stories are analyzed in the context of career and conjugal life transitions. They illuminate the link between the adoption of market novelty and new intermediate social strata. The Chinese context of transition and reforms after 1978 appears as a typical locus for this double configuration.
30

L'écriture de l'histoire dans l'oeuvre de Mark Twain : un imaginaire de la trace / Mark Twain's Historical Imagination : The Haunting Trace

Louis-Dimitrov, Delphine 16 May 2009 (has links)
Cette thèse se donne pour enjeu de redéfinir l'identité littéraire de Mark Twain dans son articulation avec l'histoire. Clef de voûte de la mythologie nationale qui donne forme à l'identité américaine, le motif de la trace devient chez Twain un principe d'écriture où s'exprime une conscience historique dissidente. La réappropriation progressive de ce paradigme subvertit les représentations collectives pour définir une compréhension singulière de l'historicité de la nation et du devenir individuel. L'opposition entre la trace mnésique, inscription de l'histoire dans la profondeur du lieu, et la trace prospective, ébauche d'un tracé nouveau, structure dès l'origine les représentations symboliques de l'Ancien et du Nouveau Continent. À ces deux modalités de l'inscription correspondent chez Twain deux formes d'historicité, la stase et le progrès, et deux régimes politiques, la monarchie et la démocratie. Or son écriture subvertit cette polarité symbolique en dénonçant la stratification de l'histoire américaine, symptôme d'une dérive monarchique due à la perte des origines fondatrices de la nation. Se définit dès lors une économie historique où la trace des origines de la nation se révèle habitée par un régime de perte qui contamine quiconque cherche à les capter, tandis que le déterminisme des origines individuelles impose l'idée d'une fermeture de l'histoire. À l'emprise mortifère de la trace, l'écriture de Twain oppose l'utopie de la non-inscription, principe d'une sortie de l'histoire et d'une coïncidence retrouvée avec l'origine. La résurgence de tensions irrésolues dans les textes tardifs convertit cependant cette utopie en mise en scène de l'abolition de l'histoire. / : This thesis aims at redefining Mark Twain's literary identity in its articulation with history. The motif of the trace, which stands at the core of the national mythology that shapes American identity, is in Twain a writing principle expressing a dissident historical consciousness. The progressive reappropriation of this paradigm subverts collective representations and defines a singular apprehension of national and individual historicity. The opposition between the mnesic trace—which inscribes history into a place—and the prospective one—the starting point of a new tracing—lies at the root of the symbolical representations of the Old and the New Continents. In Twain's writings, these two forms of inscription correspond to two opposite modes of historicity—stasis and progress—and two political regimes—monarchy and democracy. Twain nevertheless subverts this symbolical polarity by revealing the stratification of American history. He thereby hints at a drift towards monarchy that results from the loss of the nation's founding principles. His fiction thus defines a historical economy in which the traces of the nation's origins appear to be inhabited by a principle of loss that may contaminate whoever attempts to appropriate them. The determinism of individual origins meanwhile suggests the closing down of history. To the deadly hold of the trace, his writings oppose the utopia of non- inscription – the principle of an escape from history and of a renewed coincidence with the origins. Yet the resurgence of unsolved tensions in Twain's late works converts the utopia into the staging of the abolition of history.

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