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Matrices aléatoires et leurs applications à la physique statistique et quantique / Random matrices and applications to statistical physics and quantum physicsNadal, Céline 21 June 2011 (has links)
Cette thèse est consacrée à l'étude des matrices aléatoires et à quelques unes de leurs applications en physique, en particulier en physique statistique et en physique quantique.C'est un travail essentiellement analytique complété par quelques simulations numériques Monte Carlo. Dans un premier temps j'introduis la théorie des matrices aléatoires de façon assez générale : je définis les principaux ensembles de matrices aléatoires (en particulier gaussiens) et décris leurs propriétés fondamentales (distribution des valeurs propres, densité, etc). Dans un second temps je m'intéresse à des systèmes physiques d'interfaces à l'équilibre qui peuvent être modélisés par des marcheurs ``vicieux'', c'est-à-dire des marcheurs aléatoires conditionnés à ne pas se croiser. On peut montrer que la distribution des positions des marcheurs à un temps donné est exactement celle des valeurs propres d'une matrice aléatoire. J'étudie ensuite un problème physique qui relève d'un domaine très différent, celui de l'information quantique, mais qui est également étroitement relié aux matrices aléatoires: celui de l'intrication pour des états aléatoires dans un système quantique bipartite (fait de deux sous-parties) de grande taille. Enfin je m'intéresse à certaines propriétés des matrices aléatoires comme la distribution du nombre de valeurs propres positives ou encore la distribution de la valeur propre maximale (loi de Tracy-Widom près de la moyenne et grandes déviations loin de la moyenne). / This thesis presents a study of random matrices and some applications in physics, in particular in statistical physics and quantum physics. This work is mostly analytic, but I also performed some Monte Carlo numerical simulations. First I introduce random matrix theory: I define the main random matrix ensembles (in particular Gaussian ensembles) and describe their fundamental properties (distribution of the eigenvalues, density...). Then I study a physical system of interfaces at equilibrium that can be modeled by ``vicious walkers'', ie random walkers that can not meet each other.One can show that the distribution of the positions of the walkers at a given time is the same as the distribution of the eigenvalues of a random matrix. I also consider a problem coming from a very different field, the field of quantum information theory, but that is also closely related to random matrices: the distribution of entanglement for random states in a large bipartite quatum system (made of two parts). Finally I study some properties of random matrices such as the distribution of the number of positive eigenvalues or the one of the maximal eigenvalue (Tracy-Widom and large deviations).
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As implicações dos restos a pagar na gestão da saúde pública: o caso de Mato GrossoAlencar, Alisson Carvalho de 05 November 2015 (has links)
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Previous issue date: 2015-11-05 / The health issue is the center of national and international discussion about the need for development of public policies to be adopted by public agencies. Therefore, the State has an obligation to implement public policies that provide at all, concrete actions aimed at safeguarding the right to health. From this perspective, the objective of the research is to evaluate the implications of remains to pay in the management of public health of Mato Grosso, in the years 2008 to 2014. In that intent, from documentary research, literature and field it was observed that the state is inserted into a vicious cycle of remains to pay. Expenses dammed in the period maintained a dynamic evolution, damaging the financial implementation of the priority programs of Mato Grosso health. The programmatic financial realization is no longer considered optimal in 2008, with 92% of performance, to be characterized as a regular in 2014, with 66% of execution. Through the case study, it was identified that there isn't way to Mato Grosso get excellent results in the implementation of the interests of their society if the state meets the credibility shaken as against creditors, by excessively delaying its financial commitments without respect, or have the ability to perform the approved budget, by purchasing goods and contracting services through emergency mechanisms that increase the cost of buying public and enhance the power of the companies, in the implementation of the budget. In addition to damage the budget and financial programming, creating real parallel budgets, it is concluded that the excess costs passed on the year in which should occur for subsequent, damaged the quality of public services run on state health, hindering the realization of this right fundamental, essential to life. / O tema saúde é o centro do debate nacional e internacional acerca da necessidade de evolução das políticas públicas a serem adotadas pelos órgãos públicos. Portanto, o Estado tem obrigação de executar programas que forneçam, a todos, ações concretas voltadas ao resguardo do direito à saúde. Nessa perspectiva, o objetivo da pesquisa é avaliar as implicações dos restos a pagar na gestão da saúde pública de Mato Grosso, nos anos de 2008 a 2014. Nesse intento, a partir de pesquisa documental, bibliográfica e de campo, observou-se que o Estado está inserido em um ciclo vicioso de inscrição de restos a pagar. As despesas represadas no período mantiveram uma dinâmica de evolução, prejudicando a execução financeira dos programas prioritários da saúde mato-grossense. Segundo os dados, a realização financeira programática deixou de ser considerada ótima em 2008, com 92% de realização, para caracterizar-se como regular em 2014, com 66% de execução. Por meio do estudo de caso, identificou-se que não há como Mato Grosso obter resultados excelentes na implementação dos interesses de sua sociedade se o Estado encontra-se com a credibilidade abalada em relação aos credores, por postergar seus compromissos financeiros, sem respeitar, ou ter a capacidade de executar o orçamento aprovado, adquirindo bens e contratando serviços lançando mão de mecanismos emergenciais que elevam o custo da compra pública e potencializam o poder das empresas na execução do orçamento. Além de deteriorar a programação orçamentária e financeira, criando verdadeiros orçamentos paralelos, conclui-se que o excesso de despesas repassadas do exercício em que deveriam ocorrer para os subsequentes, prejudicou a qualidade dos serviços públicos executados na saúde do Estado, dificultando a realização deste direito fundamental, imprescindível à vida.
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Itämeren rehevöitymisen uudistettu diagnoosi ja paradigmaLappalainen, K. M. (K. Matti) 01 June 2018 (has links)
Abstract
The eutrophication of the Baltic Sea continues despite decrease of the external phosphorus load by as much as 80% of the target confirmed by HELCOM. The aim of this thesis is to investigate this paradox, critically evaluate previous explanations for the persistent eutrophication, and to introduce a new diagnosis and paradigm for the causes and processes behind eutrophication of the Baltic Sea.
According to the current consensus, anthropogenic nutrient loading is nearly the sole cause of eutrophication and regular cyanobacterial blooms. However, this study shows that the areal phosphorus loading rate, when modeled properly, is surprisingly low, and unlikely to be the primary cause of eutrophication. Instead, the frequency of the salt water pulses has decreased dramatically during the past 40 years. This is the root cause of eutrophication, via the hyper-vicious cycle of the hypoxic and finally anoxic conditions of the deeps causing internal phosphorus loading, denitrification, and nitrogen and carbon fixation. Furthermore, this work confirms that nitrogen fixation increases in low nitrogen conditions, further increasing eutrophication and cyanobacterial blooms. Thus, the most effective way to break the cycle of eutrophication is to improve the oxygen conditions of the deeps, which really is impossible to achieve by decreasing external loading alone.
A key result of this work is that natural processes, rather than human activity, plays a decisive role in the eutrophication process – a perspective that typically faces substantial resistance. This thesis discusses how sociological and political views have affected the scientific community and its pursuit to model the mechanisms of eutrophication of the Baltic Sea.
In conclusion, this study leads to important novel insights by providing new models for calculating the external and internal phosphorus loads of the Baltic Sea, with results highlighting the importance of natural processes of internal loading from the anoxic deeps. Altogether, this thesis introduces a new a paradigm for eutrophication of the Baltic Sea. / Tiivistelmä
Itämeri rehevöityy edelleen, vaikka fosforikuormitusta on vähennetty 80 % tavoitellusta. On siis syytä tutkia miksi Itämeren tila ei ole parantunut.
Syntyneen ristiriidan ratkaisemiseksi tarkoituksena on etsiä aiemmista tulkinnoista ristiriitoja, korjata ne ja uudistaa tietopohja uudeksi ja toimivammaksi paradigmaksi. Virhetulkintojen tunnistamiseen sovelletaan Popperin falsifikaatiomenettelyn periaatteita.
Konsensuksen mukaan ihmisperäinen kuormitus on lähes yksinomainen syy (sinilevä)rehevyyteen. Kuitenkin Vollenweiderin mallin mukaan tehty, hydrologialla painotettu fosforin pintakuormitus on ollut 1970 - 1980-luvuilla vain lievää rehevyyttä edellyttävällä tasolla. Ulkoinen kuormitus ei siten voi olla suurin rehevyyden aiheuttaja.
Sinilevärehevyyttä ylläpitävänä päätekijänä on syvävesiin happea tuovien suolavesipulssien toistuvuuden romahtaminen. Siitä syntyneet syvävesien ja -pohjien hapettomuudet aiheuttavat Gotlanninmeressä sekä sisäistä kuormitusta että lisärehevöittävää typen- ja hiilensidontaa. Yhdessä näitä prosesseja nimitetään nyt supernoidankehäksi.
Johtopäätöksiä:
• Ihmistieteelliset ja ympäristöpoliittiset näkemykset vaikuttavat luonnontieteellisiin tulkintoihin luultua enemmän.
• Suolavesipulssien harventuminen on hapettomuus- ja rehevyyskierteen perussyy.
• Syvänteiden hapettomuus on kaikkialle negatiivisesti säteilevä keskeistekijä.
• Itämeren supernoidankehä on purettava saattamalla syvänteet hapellisiksi.
• Hapellisuutta ei voida saada aikaan ulkoisen kuormituksen vähentämisellä.
• Jäljelle jäävät siten teknologiset keinot, joista toteutuskelvollisimmalta näyttää Itämeren hapellisimman ja kylmimmän veden pumppaus 30 metrin syvyydestä syvänteisiin, mikä tehostaa myös pulssivesien virtausta syvänteiden pohjalle.
Tämä väitöskirja sisältää viisi vallitsevasta paradigmasta poikkeavaa tulosta:
1. Itämerelle on kehitetty rehevyyden uusi diagnoosi ja paradigma,
2. Luonto dominoi Itämeren tilaa, ei ihminen,
3. Typensidonnalla on lisärehevöittävä mekanismi,
4. Itämerelle on kehitetty uusi fosforin sisäkuormituksen laskentamenetelmä,
5. Virtuaalisen fosforikuormituksen laskenta.
Ilman Gotlanninmeren syvänteiden hapellisuutta Itämeri on tuomittu pysymään rehevyyden supernoidankehässä, ’kaksinkertaisessa takalukossa’.
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Challenges and opportunities of development in Ethiopia through urban-rural economic linkages (URELs)Berhanu Zeleke Gobaw 07 1900 (has links)
The transformation of rural people and land to urban land and culture is a natural
discourse and inevitable process. In the process, more than half of the current world
population are living in urban centres. The number of urban centres and their population
is rapidly increasing while the situation of integrated development of urban centres and
rural areas such URELs for sustainable development have given less attention in
agricultural based countries (ABCs). Multi-disciplinary (agriculture and agro-industries)
integration, multi-spatial (urban centre and its hinterlands) linkages, multiscalar (micromeso
and macro) levels, multi-actors and stakeholders involvement are the noteworthy
innovations in the field of development studies. This study mainly focused on URELs for
agribusiness and value chains under the development themes of governance and
development as well as contemporary debates. Policies, institutional settings and practical
implementation strategies of integrated and balanced development discourse of basic
sectoral and urban-rural economic linkages (URELs) missed in ABCs such as Ethiopia‟s
comprehensive development policy ADLI neglecting the rapidly growing urban centres.
Owing to this, this study is designed to examine the challenges and problems, status and
agribusiness and efficiencies of URELs for exploring theoretical empirical model for
virtuous circle URELs. Methodologically, the study used sequential explanatory mixed
methods research and cross-sectional survey design. The sequential approach was
quantitative method, qualitative method and integrating the two findings on interpretation
and discussion. The findings present truncated BPLs and FPLs of agriculture and agroindustries.
It was was mainly due to poor and greater ranges of efficiency from TE, AE
and EE for both agriculture and agro-industries, form of government as ethnic-federalism
and regionalism, violation of the existing institutional frameworks, dejure-defacto
discrminatin, government businesses, policy and institutional settings, lack of R&D,
many paradoxical acts and poor resources mobilization and utilization. These problems
and challenges are taken as potential opportunities for improvement and new lens of
developing empirical model. The overall recommendation lies on creating enabling
environment for virtuous circle URELs and integrated regional development using
regional development approach, avoiding illegal interventions, import-export balance,
proper resource mobilization and utilization. / Development Studies / D. Litt. et Phil. (Development Studies)
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