Stability of the curvature perturbation in dark sectors` mutual interacting models

We consider perturbations in a cosmological model with a small coupling between dark energy and dark matter. We prove that the stability of the curvature perturbation depends on the type of coupling between dark sectors. When the dark energy is of quintessence type, if the coupling is proportional to the dark matter energy density, it will drive the instability in the curvature perturbations: however if the coupling is proportional to the energy density of dark energy, there is room for the stability in the curvature perturbations. When the dark energy is of phantom type, the perturbations are always stable, no matter whether the coupling is proportional to the one or the other energy density. (C) 2008 Elsevier B.V. All rights reserved.

Border trees of complex networks

The comprehensive characterization of the structure of complex networks is essential to understand the dynamical processes which guide their evolution. The discovery of the scale-free distribution and the small-world properties of real networks were fundamental to stimulate more realistic models and to understand important dynamical processes related to network growth. However, the properties of the network borders (nodes with degree equal to 1), one of its most fragile parts, remained little investigated and understood. The border nodes may be involved in the evolution of structures such as geographical networks. Here we analyze the border trees of complex networks, which are defined as the subgraphs without cycles connected to the remainder of the network (containing cycles) and terminating into border nodes. In addition to describing an algorithm for identification of such tree subgraphs, we also consider how their topological properties can be quantified in terms of their depth and number of leaves. We investigate the properties of border trees for several theoretical models as well as real-world networks. Among the obtained results, we found that more than half of the nodes of some real-world networks belong to the border trees. A power-law with cut-off was observed for the distribution of the depth and number of leaves of the border trees. An analysis of the local role of the nodes in the border trees was also performed.

Refraction corrected transmission ultrasound computed tomography for application in breast imaging

Purpose: We present an iterative framework for CT reconstruction from transmission ultrasound data which accurately and efficiently models the strong refraction effects that occur in our target application: Imaging the female breast. Methods: Our refractive ray tracing framework has its foundation in the fast marching method (FNMM) and it allows an accurate as well as efficient modeling of curved rays. We also describe a novel regularization scheme that yields further significant reconstruction quality improvements. A final contribution is the development of a realistic anthropomorphic digital breast phantom based on the NIH Visible Female data set. Results: Our system is able to resolve very fine details even in the presence of significant noise, and it reconstructs both sound speed and attenuation data. Excellent correspondence with a traditional, but significantly more computationally expensive wave equation solver is achieved. Conclusions: Apart from the accurate modeling of curved rays, decisive factors have also been our regularization scheme and the high-quality interpolation filter we have used. An added benefit of our framework is that it accelerates well on GPUs where we have shown that clinical 3D reconstruction speeds on the order of minutes are possible.

The Construction of Identity in Edwidge Danticat's The Farming of Bones

The Farming of Bones deals with issues surrounding the dynamic connections between identity and boundary construction in post-colonial context. It will present an analysis of how the novelist problematizes and communicates her idea of social and national identity construction to her readers and how the readers can identify themselves with the struggles and challenges of the protagonist Amabelle who is trying to find her own identity. This essay will show how Danticat’s novel contributes to an understanding of national identity beyond borders and makes the reader take the role of an individual who constructs her identity by uncovering moments of raw humanness. Until now, no literary scholar has examined the protagonist’s therapeutic role in bridging this social and national gap. Instead critics have discussed other issues of the novel like crossing and re-crossing the border, love, dreams, etc. Although this scholarship has been very effective and rewarding, it lacks any focus on the complexity of the characters’ identity construction. Therefore, this paper will reconsider Danticat’s The Farming of Bones with a closer attention to the question of identity.

Electricity Supply Solutions for an Educational Center in Tanzania

The aim of this study was to investigate electricity supply solutions for an educationalcenter that is being built in Chonyonyo Tanzania. Off-grid power generation solutions andfurther optimization possibilities were studied for the case.The study was done for Engineers Without Borders in Sweden. Who are working withMavuno Project on the educational center. The school is set to start operating in year 2015with 40 girl students in the beginning. The educational center will help to improve genderequality by offering high quality education in a safe environment for girls in rural area.It is important for the system to be economically and environmentally sustainable. Thearea has great potential for photovoltaic power generation. Thus PV was considered as theprimary power generation and a diesel generator as a reliable backup. The system sizeoptimization was done with HOMER. For the simulations HOMER required componentdata, weather data and load data. Common components were chose with standardproperties, the loads were based on load estimations from year 2011 and the weather datawas acquired from NASA database. The system size optimization result for this base casewas a system with 26 kW PW; 5.5 kW diesel generator, 15 kW converter and 112 T-105batteries. The initial cost of the system was 55 875 €, the total net present cost 92 121 €and the levelized cost of electricity 0.264 €/kWh.In addition three optimization possibilities were studied. First it was studied how thesystem should be designed and how it would affect the system size to have night loads(security lights) use DC and could the system then be extended in blocks. As a result it wasfound out that the system size could be decreased as the inverter losses would be avoided.Also the system extension in blocks was found to be possible. The second study was aboutinverter stacking where multiple inverters can work as one unit. This type of connectionallows only the required number of inverters to run while shutting down the excess ones.This would allow the converter-unit to run with higher efficiency and lower powerconsumption could be achieved. In future with higher loads the system could be easilyextendable by connecting more inverters either in parallel or series depending on what isneeded. Multiple inverters would also offer higher reliability than using one centralizedinverter. The third study examined how the choice of location for a centralized powergeneration affects the cable sizing for the system. As a result it was found that centralizedpower generation should be located close to high loads in order to avoid long runs of thickcables. Future loads should also be considered when choosing the location. For theeducational center the potential locations for centralized power generation were found outto be close to the school buildings and close to the dormitories.

Optimization heuristic solutions, how good can they be? : With empirical applications in location problems

Combinatorial optimization problems, are one of the most important types of problems in operational research. Heuristic and metaheuristics algorithms are widely applied to find a good solution. However, a common problem is that these algorithms do not guarantee that the solution will coincide with the optimum and, hence, many solutions to real world OR-problems are afflicted with an uncertainty about the quality of the solution. The main aim of this thesis is to investigate the usability of statistical bounds to evaluate the quality of heuristic solutions applied to large combinatorial problems. The contributions of this thesis are both methodological and empirical. From a methodological point of view, the usefulness of statistical bounds on p-median problems is thoroughly investigated. The statistical bounds have good performance in providing informative quality assessment under appropriate parameter settings. Also, they outperform the commonly used Lagrangian bounds. It is demonstrated that the statistical bounds are shown to be comparable with the deterministic bounds in quadratic assignment problems. As to empirical research, environment pollution has become a worldwide problem, and transportation can cause a great amount of pollution. A new method for calculating and comparing the CO2-emissions of online and brick-and-mortar retailing is proposed. It leads to the conclusion that online retailing has significantly lesser CO2-emissions. Another problem is that the Swedish regional division is under revision and the border effect to public service accessibility is concerned of both residents and politicians. After analysis, it is shown that borders hinder the optimal location of public services and consequently the highest achievable economic and social utility may not be attained.

L'Homme sous le masque : Une étude du personnage principal dans Le Fantôme de l'Opéra

L’objet de la présente étude est le personnage principal dans l’oeuvre Le Fantôme de l’Opéra de Gaston Leroux. Le but de cette analyse littéraire est de mettre en évidence l'ambiguïté et la complexité psychologique et morale de ce personnage.L’analyse est basée sur les théories de Vincent Jouve à propos de la perception du personnage romanesque. Le résultat de l'analyse montre que l'ambiguïté du personnage principal peut être déduite de ce que Jouve appelle le « système de la sympathie » constitué de trois codes : le code narratif, le code affectif et le code culturel.

Design and use of mobile technology in distance language education : Matching learning practices with technologies-in-practice

This thesis focuses on the adaptation of formal education to people’s technology- use patterns, theirtechnology-in-practice, where the ubiquitous use of mobile technologies is central. The research question is: How can language learning practices occuring in informal learning environments be effectively integrated with formal education through the use of mobile technology? The study investigates the technical, pedagogical, social and cultural challenges involved in a design science approach. The thesis consists of four studies. The first study systematises MALL (mobile-assisted language learning) research. The second investigates Swedish and Chinese students’ attitudes towards the use of mobile technology in education. The third examines students’ use of technology in an online language course, with a specific focus on their learning practices in informal learning contexts and their understanding of how this use guides their learning. Based on the findings, a specifically designed MALL application was built and used in two courses. Study four analyses the app use in terms of students’ perceived level of self-regulation and structuration. The studies show that technology itself plays a very important role in reshaping peoples’ attitudes and that new learning methods are coconstructed in a sociotechnical system. Technology’s influence on student practices is equally strong across borders. Students’ established technologies-in-practice guide the ways they approach learning. Hence, designing effective online distance education involves three interrelated elements: technology, information, and social arrangements. This thesis contributes to mobile learning research by offering empirically and theoretically grounded insights that shift the focus from technology design to design of information systems.

Bordering on Disaster?

Borders, the bookstore, provides us with an instructive case study regarding our collective futures. While Amazon and Barnes & Noble made changes that both streamlined and changed their services, Borders followed the “business as usual” model. That led to Chapter 11, the closing of nearly a third of their stores, and a complete restructuring of all that’s left. Not many industry analysts think even this will be enough to keep the company afloat.

Trade and infrastructure: evidences from the Andean Community

This paper presents evidence on the key role of infrastructure in the Andean Community trade patterns. Three distinct but related gravity models of bilateral trade are used. The first model aims at identifying the importance of the Preferential Trade Agreement and adjacency on intra-regional trade, while also checking the traditional roles of economic size and distance. The second and third models also assess the evolution of the Trade Agreement and the importance of sharing a common border, but their main goal is to analyze the relevance of including infrastructure in the augmented gravity equation, testing the theoretical assumption that infrastructure endowments, by reducing trade and transport costs, reduce “distance” between bilateral partners. Indeed, if one accepts distance as a proxy for transportation costs, infrastructure development and improvement drastically modify it. Trade liberalization eliminates most of the distortions that a protectionist tariff system imposes on international business; hence transportation costs represent nowadays a considerably larger barrier to trade than in past decades. As new trade pacts are being negotiated in the Americas, borders and old agreements will lose significance; trade among countries will be nearly without restrictions, and bilateral flows will be defined in terms of costs and competitiveness. Competitiveness, however, will only be achieved by an improvement in infrastructure services at all points in the production-distribution chain.

O movimento E.C.R.: estudo de caso Sendas

Este estudo demonstrou os impactos do E.C.R. ¿ Resposta Eficiente ao Consumidor na cadeia de suprimentos de uma empresa de varejo, precisamente do grupo Sendas, empresa esta que busca na logística um diferencial competitivo para sobreviver neste mercado acompanhando as mudanças e as melhorias operacionais no fluxo de produtos e das operações, causadas pela evolução tecnológica que o varejo vem sofrendo nos últimos anos. Para tanto foram realizadas pesquisas bibliográfica e documental, de forma a embasar conceitualmente e com informações relevantes a caracterização da empresa inserindo a mesma neste contexto de cadeia de suprimentos e foco no cliente, estabelecendo uma relação entre a empresa pesquisada e a aplicação da tecnologia existente. Quanto aos aspectos relacionados aos ganhos de eficiência, houve uma preocupação com a implantação das ferramentas do E.C.R. como um fator determinante para a perpetuação do negócio. Os ganhos de eficiência permitiram a empresa este diferencial competitivo na disputa pelo mercado, certamente outros aspectos como atendimento são relevantes para garantir a eficiência da cadeia, portanto, avaliamos as interfaces entre os participantes da cadeia (fabricantes, fornecedores), grupo Sendas (varejista) e consumidores. Assim, concluímos este estudo mapeando pontos fortes e fracos desta relação, identificando as barreiras a serem vencidas e algumas recomendações.

Estratégias de internacionalização: investimentos diretos externos de multinacionais brasileiras

With the improvement of the international trade on the last decades, the Brazilian firms are searching to operate beyond the national borders in order to guarantee its presence on the key markets. The dissertation aimed to analyze the motivations and the strategies of internationalization implemented by the firms: Petrobras, Vale, Embraer, Gerdau and Marcopolo as well as determine the existence of a dominant strategy. In order to do that, Dunning¿s eclectic paradigm and the strategies of internationalization supported by him were revised along with the main literature from Brazilian authors on the internationalization process of the selected firms. The comparative analysis between the strategies of internationalization selected and the industrial sector, origin of capital and the preferred mode of entrance on the markets were done through an exploratory research, with a qualitative character and collection of secondary data from the internationalization process of the firms. At the end of this research, it was possible to identify that each firm had adopted a predominant strategy however it was also possible to observe that new strategies were aggregated in complementation of the previous one. Besides that, no evidence was found between the predominant strategy of internationalization and the origin of the capital neither with the preferred mode of entrance.

Palestinos no extremo sul do Brasil : identidade étnica e os mecanismos de produção da etnicidade. Chuí/RS

Este trabalho trata da identidade palestina e dos processos sociais de construção de identidade étnica observados no extremo sul do Brasil. Focaliza os processos de recriação de tradições e as negociações sociais que agiram no sentido de configurar um grupo étnico. Este estudo é uma etnografia desenvolvida a partir da observação participante e da análise de documentos produzidos pelos entrevistados que vivem na Chuí (Rio Grande do Sul) na fronteira entre Brasil e Uruguai. Através da investigação de uma das falas recorrentes - “aqui é tudo palestino” -, revela-se o universo de situações sociais e negociações que configuram uma identidade social e os conflitos envolvidos na produção de uma “comunidade árabe” como um grupo minoritário. Analisa-se as expressões da identidade social relativas a um reconhecimento como palestinos, focalizando as diversas ações empreendidas do início da década de 80 até o fim dos anos 90. O estudo aborda os mecanismos e processos sociais que deram vitalidade à identidade social e à proeminência de uma identidade étnica, entre eles: as viagens à Palestina e o modo como estas viagens incidem sobre a descoberta da identidade palestina; as festas de casamentos que estreitam laços entre famílias e que reverberam na produção de uma “família árabe”; e o interesse pela política partidária local como um palco específico em que uma identidade social se configura como identidade étnica, traçando fronteiras simbólicas e revitalizando a preocupação com os destinos e lideranças da “comunidade árabe”.

Tecnologia de informação e colaboração interorganizacional: um estudo no varejo de grande porte no setor de confecção

A colaboração interorganizacional, é uma realidade que atinge muitas empresas, de todos os portes e setores. A TI aumenta a capacidade de gerenciamento e coordenação através de fronteiras organizacionais, permitindo redução de custos, otimização de recursos e melhor coordenação e o controle gerencial. Este projeto identificou o papel da TI nos relacionamentos colaborativos entre empresas. Para isso, analisou-se o emprego da TI no relacionamento colaborativo entre varejistas e fornecedores, no Setor de Confecção. Como resultado da pesquisa, os conceitos estabelecidos foram organizados em um modelo teórico e resumidos em um constructo sobre a colaboração interorganizacional apoiada pela TI.

The Chandler-Furtado case: a decolonial reframing of a North/South (dis)encounter

A partir de uma perspectiva descolonial das bordas do Sul, este trabalho mostra que, apesar de Alfred Chandler e o brasileiro Celso Furtado terem muito a contribuir para a construção de um campo de estratégia multipolar, foi somente o primeiro que se tornou uma autoridade em gestão estratégica. Ao longo de mais de 50 anos Chandler e Furtado pesquisaram sobre o mesmo objeto, mas a partir de diferentes perspectivas. Contudo, defendemos que suas pesquisas são partes inseparáveis de um mesmo fenômeno, da mesma maneira que modernidade e colonialidade são, e que é necessário a descolonialidade para promover o encontro a que se propõe fazer este trabalho. Chandler defendia nos anos 60 que a grande corporação, liderada pelos gestores, era o grande motor do capitalismo americano; enquanto que no Sul, Furtado argumentava que o estado, através de planejamento e investimento, deveria liderar a saída do Brasil da condição de subdesenvolvimento, a qual lhe fora imposta principalmente pelo Norte. A crise atual da hegemonia americana sugere que devemos recuperar os argumentos de Furtado e discutir a difusão assimétrica do conhecimento e das instituições em administração na América Latina durante o período da Guerra Fria. Neste trabalho propomos uma estrutura com três níveis de análise para reavaliar este (des)encontro entre Chandler-Furtado através de perspectivas independentes: a grande narrativa da Guerra Fria, o conhecimento subalterno e a identidade nacional. Nosso objetivo é promover um mundo multipolar através dos campos da administração e gestão estratégica.