Made available in DSpace on 2016-06-02T20:15:27Z (GMT). No. of bitstreams: 1 TeseEBH.pdf: 1014685 bytes, checksum: 03a8fa9077824264976a30184e804bb7 (MD5) Previous issue date: 2003-12-08 / Universidade Federal de Minas Gerais / We study the relativistic two-body problem of the action-at-a-distance electrodynamics. This dynamical system appeared 100 years ago as a time-symmetric relativistic motion and acquired the status of electrodynamics in the 1940 s by the works of Dirac, Wheeler and Feynman. The equations of motion for this problem are delay equations involving retarded and advanced arguments symmetrically. We outline our dynamical studies with an emphasis on the physics of this complex conservative dynamical system. We study the following versions of this electromagnetic two-body problem: (i) For the case of two arbitrary masses with attractive interaction (hydrogen atom), we develop a numerical method to integrate the three-dimensional motion. This method has a very limited applicability and could not answer several dynamical questions. We calculated numerically some orbits. The difficulties of this complex case suggested that we should restrict the study to the simpler problem of straight-line orbits and equal masses ( (ii) and (iii) ). (ii) We study the colinear orbits of the repulsive problem of two electrons (two electrons moving on the same line). We obtain an analytical approximation for the low-energy colinear orbits. We also develop a stable numerical method based on steepest-descent minimization. Using this method we calculated the orbits numerically for several energies. We also found a two-degree-of-freedom implicit Hamiltonian formalism to describe this colinear motion. (iii) For the attractive problem with equal masses, we derive an equation of motion that is regular at the collision. Our method uses the energy constant related to the Poincaré invariance of the theory to motivate the regularizing coordinate transformation and to remove infinities from the equation of motion. The collision orbits are calculated numerically using the regular equation adapted in a self-consistent minimization method (a stable numerical method that chooses only nonrunaway orbits). We compare our regularization of this Poincaré-invariant case to the Levi-Civita regularization of the Galilei-invariant Kepler problem. / Neste trabalho nós estudamos o problema relativístico de dois corpos na eletrodinâmica de ação à distância. Este sistema dinâmico foi proposto no começo do século passado como exemplo de dinâmica relativística e ganhou status de eletrodinâmica nos anos 40 com os trabalhos de Dirac, Wheeler e Feynman. As equações de movimento deste problema envolvem argumentos retardados e avançados simetricamente, são pouco estudadas e difíceis de resolver. Nós tentamos entender a dinâmica deste sistema com ênfase na física deste complexo sistema dinâmico conservativo. Nós estudamos os seguintes casos do problema de dois corpos: (i) Nós começamos o estudo com o problema geral atrativo de massas arbitrárias e órbitas em três dimensões (o átomo de Hidrogênio). Nós desenvolvemos um método numérico para este problema, que apresentou muitas limitações. Nós calculamos numéricamente algumas órbitas com esse método, mas algumas limitações não possibilitaram um estudo completo da dinâmica neste caso. Alguns fracassos iniciais nos levaram a restringir o estudo ao problema mais simples de órbitas colineares e massas iguais ( (ii) e (iii) ). (ii) Para o problema colinear repulsivo de dois elétrons, nós obtivemos uma aproximação analítica para as órbitas repulsivas de baixa energia e desenvolvemos um método numérico estável baseado em minimização. Usando este método nós calculamos numericamente as órbitas para várias energias. Nós também obtivemos uma descrição Hamiltoniana com dois graus de liberdade para a dinâmica colinear, na forma de um Hamiltoniano implícito. (iii)Para o problema colinear atrativo com massas iguais, nós derivamos equações de movimento que são regulares na colisão. Para isso usamos as integrais de Noether do problema de dois corpos relativístico como motivação e também para remover infinitos da equação de movimento. O procedimento desenvolvido é análogo à regularização de Levi-Civita do problema de Kepler. Estas equações regulares foram adaptadas num método numérico estável baseado em minimização, análogo ao desenvolvido em (ii). Usando este método, nós calculamos numericamente orbitas para várias energias no caso atrativo.

Orientadores : Marcelo Dascal, Rodolfo Ilari / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Filosofia e Ciencias Humanas / Made available in DSpace on 2018-07-19T00:36:35Z (GMT). No. of bitstreams: 1 Bechara_EliNazareth_M.pdf: 2563025 bytes, checksum: 9d89a0ce6a2b89496d05b13340cd88be (MD5) Previous issue date: 1976 / Resumo: A presente investigação visa uma tentativa de evidenciar, por processos sintáticos e semânticos, que o verbo existir tradicionalmente classificado como um único verbo, intransitivo e pessoal, poderia ser descrito ora tendo duas entradas lexicais distintas, ora como tendo uma única. Para mostrar que isto é um fnto, descrevemos no capitulo I sentenças em aue ambos ocorrem. Na primeira parte, abstraímos duas entradas lexicais distintas para existir, segundo a teoria de Chomsky(1965), examinando tal hipótese à luz de sentenças em que ocorre a partlcula exclusiva só. Na segunda parte, damos evidência de uma única entrada lexical para existir, segundo a teoria de Fillmore(1969), e outros. No capítulo II, damos fundamentos semânticos, segundo a téoria de Katz(1964), sobre sentenças analíticas, sintéticas ou contraditórias. Examina-se neste capitulo que o verbo existir do português contém sentidos que se opõem lexicalmente, e para comprovar tal fato, tomam-se sentenças complexas em que ambos ocorrem - um/numa sentenças afirmativa e o outro, numa negativa, aparentemente contraditória àquela - e se comprova que tais sentenças não são contradítórias entre si. Este trabalho foi feito concentrando-se atenções sobre a língua portuguesa e, provavelmente, se poderia generalizar a outras linguas naturais (e.g. Francês, Inglês, Alemão, etc.) / Mestrado / Mestre em Linguística

Since the Vietnamese Communist Party passed the resolution to implement the ¡§Doi Moi¡¨ policy in the sixth National Congress in December 1986, Vietnam¡¦s economy has transformed from state-controlled economic system to market and socialism-oriented economy. This change of economic system has contributed to the recent economic improvement in Vietnam, a key point of studying Vietnam¡¦s political development. On the perspective of political economy, modernization theory contends that economic development helps political democratization, whereas stably hegemony theory argues that economic achievement may bring about stability for authoritarian regimes. Based on state theory, this paper takes two dimensions, i.e. state autonomy and state capacity, to examine the issue whether the Vietnamese state will be influenced after Vietnam¡¦s political and economic reforms. This paper concludes that modernization theory is not able to explain the current political economy of Vietnam, because Vietnam did not change from a strong state to a weak state. Rather, Vietnam maintains a strong state, which fits the explanation of state theory.

The United States and Vietnam broke the deadlock after-Vietnam-War in 1995, and both of them make far progress on the fields of economy and strategic safety. Vietnam has performed well on economic development since the Doi Moi in 1991. In 2001, USA and Vietnam signed the trade agreement and developed faster. The relationship between USA and Vietnam gradually recovered in the past ten years, and which played an important role of Asia circumstance and region safety. In the process of normalization of the relationship between two countries, there are several China¡¦s factors such political, economic, and strategic benefits for both sides. Therefore, when researching USA strategy for South East Asia, Vietnam plays an important role. This research is based on geopolitics to study the process and factors of USA and Vietnam relationship. Then it could see that their relationship will develop faster and closer.

New corrole–BODIPY conjugates have been synthesized in high yield under mild conditions. Upon excitation at the absorption maximum of the BODIPY antenna chromophore, the fluorescence intensity of the free base corrole–BODIPY conjugate increases by ca. 300%, and significant phosphorescence intensity is observed for the iridium(III) complex of the conjugate, while almost no phosphorescence is observed for the parent iridium(III) corrole, due to through-bond energy transfer from the BODIPY antenna-chromophore to the corrole core. / Original publication is available at http://dx.doi.org/10.1039/c5ra07250f / Arbortext Advanced Print Publisher 9.1.510/W Unicode / Acrobat Distiller 8.1.0 (Windows); modified using iText� 5.3.3 �2000-2012 1T3XT BVBA (AGPL-version)

A lipophilic and electron-rich phthalocyanine (α,α′-n-OC5H11)8-H2Pc and its nickel(II) complex (α,α′-n-OC5H11)8-Ni(II)Pc have been synthesized and characterized. Detailed analyses of the electronic structure were carried out by spectroscopy, electrochemistry, spectroelectrochemistry, and TD-DFT calculations. A series of experiments demonstrate that the (α,α′-n-OC5H11)8-Ni(II)Pc complex can be used as a catalyst for highly efficient carbonyl reductions. / Original publication is available at http://dx.doi.org/10.1039/C5DT03256C

Most definitions of ecotourism refer to nature travel experiences which promote the conservation of visited ecosystems. The purpose of this study is to investigate the demand side of ecotourism within the broader tourism context. To this end, the study compares ecotourists with other tourist types, on the basis of conservation involvement and socio-demographic characteristics. Moreover, the study examines recreation specialization among birders, as one subset of ecotourists, and evaluates the substitutability of ecotourism activities. A case study was undertaken at Doi Inthanon National Park, Thailand, which, in 1993, attracted over 900,000 visitors. Primary methods included personal interviews (n = 857) to collect visitor data and participant observations to document impacts from ecotourism. Based on activities, motivations, and researcher and respondent descriptions, a tourist typology of five groups was developed: birding ecotourists, general ecotourists, highlights general tourists, highlights travellers, and trekkers. Ecotourists were older and more educated than other tourist types. Ecotourists contributed more to general conservation efforts than other tourist types; however, for foreigners, these contributions occurred primarily in their home countries, not in Thailand. Compared to other tourist types, some environmental, economic, social, and educational impacts of ecotourists were distinct. Using the recreation specialization model, based on economic commitment and centrality-to-lifestyle, birders were divided into three sub-types: advanced-experienced, advanced-active, and novice. Conservation interest and involvement varied only slightly among birder sub-types. Advanced birders were older, more affluent, and more likely to have professional occupations than other sub-types. Motivations varied among birder sub-types. Using the recreation substitutability model, 82.7% of respondents were interested in a one-day nature trek, and 47.5% were willing to trade their current activities for this trek. Substitutability was higher for tourists with wildlife and natural environment motivations, conservation interests, higher education, and of a younger age. The results are incorporated into conceptual frameworks to aid ecotourism management and to characterize linkages between ecotourism and conservation. Implications and recommendations, relevant to the ecotourism industry, environmental and development organizations, national parks, and other government agencies, are discussed. / Graduate

Conferencia ETD2017, realizada en Washington DC, 7-9 de Agosto de 2017. / In the last three years Peru has gone through changes in the process of strengthening and disseminating open access, especially regarding digital theses and research or governmental data. Enactment of Law 30035, which establishes and regulates the Open Access National Digital Repository of Science, Technology and Innovation; the Regulations of the National Registry of Research Papers Submitted for Academic Degrees and Professional Titles, RENATI; the National Strategy for Open Governmental Data, Peru 2017-2021; and the Peruvian Open Governmental Data Model constitute all a legal framework that fosters open access. Within this context, since 2013 the Peruvian University for Applied Science, UPC, has implemented policies aimed to foster open access to academic and scientific information, as well to support the use of interoperable technological platforms. As a result, in March of 2013, the UPC Academic Repository was published. And, recently, UPC adopted as mandatory the open access publication of bachelor’s and master’s theses. In the last three years, the UPC Academic Repository ranked among the top in the Webometrics Repositories (Peru), and showed a significant improvement at the Latin American and World level: At the national level, it went from being ranked 13th in January 2013 to 3rd in January 2017. Worldwide, it went from being ranked 1,516th in January 2013 to 849th in January 2017. In Latin America, in January 2017 it was ranked 62nd among 217 repositories. All actions implemented have been complemented with the following strategies: the open access publication of the theses-related data; the use of diverse metadata standards —Dublin Core Qualifiers, ETD-MS, DRIVER 2.0 and OpenAIRE—; the use of the OAI-PMH interoperable protocol; the implementation of identifiers of digital content —DOI and Handle— and identifiers for users —ORCID and Google Profile—; and curation of digital content. Future activities will be oriented to increase visibility of the UPC repository contents. To this end, we have proposed the following: to use DOI in bachelor’s and master’s theses; increase the number of bibliographical records for theses and their data; monitor and assess consultations to UPC theses as shown by national repositories ALICIA and RENATI; and, finally, implement an automated system for managing theses integrated into the UPC Academic Repository.

Univ., Diss., 2009--Marburg. / Teilw. publ. in: Zeitschrift für Orthopädie und Unfallchirugie, 147, S. 183-187, DOI: 10.1055/s-0029-1185518.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.