969 resultados para europäische Expansion


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Dendritic cells (DCs) are the most important antigen-presenting cells of the immune system and have a crucial role in T-lymphocyte activation and adaptive immunity initiation. However, DCs have also been implicated in maintaining immunological tolerance. In this study, we evaluated changes in the CD4(+) CD25(+) Foxp3(+) T-cell population after co-culture of lymph node cells from BALB/c mice with syngeneic bone marrow-derived DCs. Our results showed an increase in CD4(+) CD25(+) Foxp3(+) T cells after co-culture which occurred regardless of the activation state of DCs and the presence of allogeneic apoptotic cells; however, it was greater when DCs were immature and were pulsed with the alloantigen. Interestingly, syngeneic apoptotic thymocytes were not as efficient as allogeneic apoptotic cells in expanding the CD4(+) CD25(+) Foxp3(+) T-cell population. In all experimental settings, DCs produced high amounts of transforming growth factor (TGF)-beta. The presence of allogeneic apoptotic cells induced interleukin (IL)-2 production in immature and mature DC cultures. This cytokine was also detected in the supernatants under all experimental conditions and enhanced when immature DCs were pulsed with the alloantigen. CD4(+) CD25(+) Foxp3(+) T-cell expansion during co-culture of lymph node cells with DCs strongly suggested that the presence of alloantigen enhanced the number of regulatory T cells (Tregs) in vitro. Our data also suggest a role for both TGF-beta and IL-2 in the augmentation of the CD4(+) CD25(+) Foxp3(+) population.

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A versatile and metal-free approach for the synthesis of molecules bearing seven- and eight-membered rings is described. The strategy is based on the ring expansion of 1-vinylcycloalkanols (or the corresponding silyl or methyl ether) mediated by the hypervalent iodine reagent HTIB (Phl(OH)OTs). The reaction condition can be easily adjusted to give seven-membered rings bearing different functional groups. A route to medium-ring lactones was also developed.

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Vårt examensarbete i informatik är utfört på ett producerande företag som expanderat och därför sett behov av att förändra sin organisation. Ägarna upplever att personalplanering och tillverkningsplanering är alltför tidskrävande och de hinner inte med viktiga arbetsuppgifter som marknadsföring och företagsutveckling.Examensarbetet har innefattat teoristudier, en analys av företagets verksamhet samt utformning av förändringsförslag för att förbättra företagets organisation. Våra litteraturstudier har bestått av inläsning av teorier om problem som kan uppstå i expanderande företag samt datainsamling genom intervjuer av företagets ägare och några av de anställda. Detta har legat till grund för den verksamhetsanalys vi genomfört med hjälp av delar ur metoden FA/SIM. Denna analys ligger till grund för de förändringsförslag som har arbetats fram.I analysen har problem som rör följande fyra aktiviteter identifierats. - Arbetsledning - Planering - Tillverkning - VaruleveransDe åtgärdsförslag vi anser viktigast att genomföra för att effektivisera och underlätta arbetssituationen för ägare och anställda är att börja registrera ordrar dagligen och införa rutiner för att registrera produktion och lagerhållning. Ytterligare åtgärder är att anställa kvalificerad personal på kontoret samt utbilda fler i personalen i att köra lackeringen.Vi kan konstatera att företagets övergripande problem till stor del orsakas av att organisationen inte anpassats till företagets expansion. Det är vanligt att insikt om detta kommer först när problemen börjar kännas oöverstigliga.

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The drivers for entry and expansion modes of multinational enterprises (MNEs) have been studied by several authors over the last decades but empirical results have been historically mixed. More recently, Hennart (2009) argued that the reason for the inconsistent results to date resided in the fact that prior theories assumed that local markets could be freely accessed based on a unilateral decision by the MNEs, and then proposes an alternative framework in which the entry and expansion modes of MNEs in foreign countries are a solution based on the relative efficiency of both markets. In this study, the proposed framework is tested against the prior theories based on investments made by U.S.-based MNEs in Brazil from 2005 to 2010. The results suggest that the local market characteristics, more specifically the concentration ratio at the firm and asset levels, are indeed important to influence the entry and expansion mode of U.S.-based MNEs in Brazil, reinforcing the argument against MNEs-centric theories. However, differently from Hennart’s proposition, we were not able to confirm the hypotheses that the MNEs skills are relevant to influence the final solution. We have also tested whether the difference in growth rate between the two countries could be a driver for MNEs to favor acquisition over greenfield given the opportunity cost of postponing the investments. The test result, based on our sample, was not able to confirm this hypothesis.

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In recent years, emerging countries have assumed an increasingly prominent position in the world economy, as growth has picked up in these countries and slowed in developed economies. Two related phenomena, among others, can be associated with this growth: emerging countries were less affected by the 2008-2009 global economic recession; and they increased their participation in foreign direct investment, both inflows and outflows. This doctoral dissertation contributes to research on firms from emerging countries through four independent papers. The first group of two papers examines firm strategy in recessionary moments and uses Brazil, one of the largest emerging countries, as setting for the investigation. Data were collected through a survey on Brazilian firms referring to the 2008-2009 global recession, and 17 hypotheses were tested using structural equation modeling based on partial least squares. Paper 1 offered an integrative model linking RBV to literatures on entrepreneurship, improvisation, and flexibility to indicate the characteristics and capabilities that allow a firm to have superior performance in recessions. We found that firms that pre-recession have a propensity to recognize opportunities and improvisation capabilities for fast and creative actions have superior performance in recessions. We also found that entrepreneurial orientation and flexibility have indirect effects. Paper 2 built on business cycle literature to study which strategies - pro-cyclical or counter-cyclical – enable superior performance in recessions. We found that while most firms pro-cyclically reduce costs and investments during recessions, a counter-cyclical strategy of investing in opportunities created by changes in the environment enables superior performance. Most successful are firms with a propensity to recognize opportunities, entrepreneurial orientation to invest, and flexibility to efficiently implement these investments. The second group of two papers investigated international expansion of multinational enterprises, particularly the use of distance for their location decisions. Paper 3 proposed a conceptual framework to examine circumstances under which distance is less important for international location decisions, taking the new perspective of economic institutional distance as theoretical foundation. The framework indicated that the general preference for low-distance countries is lower: (1) when the company is state owned, rather than private owned; (2) when its internationalization motives are asset, resource, or efficiency seeking, as opposed to market seeking; and (3) when internationalization occurred after globalization and the advent of new technologies. Paper 4 compared five concurrent perspectives of distance and indicated their suitability to the study of various issues based on industry, ownership, and type, motive, and timing of internationalization. The paper also proposed that distance represents the disadvantages of host countries for international location decisions; as such, it should be used in conjunction with factors that represent host country attractiveness, or advantages as international locations. In conjunction, papers 3 and 4 provided additional, alternative explanations for the mixed empirical results of current research on distance. Moreover, the studies shed light into the discussion of differences between multinational enterprises from emerging countries versus those from advanced countries.

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As globalization increases integration, a new playing field is emerging which is driving the need for operational efficiencies and alignment of complementary capabilities among countries to build sustainable models and integrated offerings. As demands increase, companies are turning to effective project management as means to control operations and countries are increasing the amount of mega projects to boost their competitiveness and global footprint. Given the scale, complexity, political nature, multicultural makeup, and high level of visibility; mega projects rely on successful stakeholder management to effectively manage its operational, tactical, and strategic levels to execute their mission. This paper examines the success drivers of mega projects and presents an in depth stakeholder assessment of the Panama Canal Expansion mega project to identify the perceived value to its stakeholder community. The stakeholder categories include: the Panama Canal Authority, subcontractors executing the expansion project, customers of the canal in Panama and U.S., as well as the communities surrounding the Panama Canal and ports in the U.S. East Coast. The conclusion of this paper captures the relationship between the effective stakeholder engagement from the Panama Canal Authority, the perceived value of the Panamanian stakeholders, and compares it to U.S. based mega projects being executed simultaneously to allow the U.S. East Coast ports to accommodate increased cargo volumes.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The paper presents an extended genetic algorithm for solving the optimal transmission network expansion planning problem. Two main improvements have been introduced in the genetic algorithm: (a) initial population obtained by conventional optimisation based methods; (b) mutation approach inspired in the simulated annealing technique, the proposed method is general in the sense that it does not assume any particular property of the problem being solved, such as linearity or convexity. Excellent performance is reported in the test results section of the paper for a difficult large-scale real-life problem: a substantial reduction in investment costs has been obtained with regard to previous solutions obtained via conventional optimisation methods and simulated annealing algorithms; statistical comparison procedures have been employed in benchmarking different versions of the genetic algorithm and simulated annealing methods.

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In this paper, an efficient genetic algorithm (GA) is presented to solve the problem of multistage and coordinated transmission expansion planning. This is a mixed integer nonlinear programming problem, difficult for systems of medium and large size and high complexity. The GA presented has a set of specialized genetic operators and an efficient form of generation of the initial population that finds high quality suboptimal topologies for large size and high complexity systems. In these systems, multistage and coordinated planning present a lower investment than static planning. Tests results are shown in one medium complexity system and one large size high complexity system.

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A combinatorial mathematical model in tandem with a metaheuristic technique for solving transmission network expansion planning (TNEP) using an AC model associated with reactive power planning (RPP) is presented in this paper. AC-TNEP is handled through a prior DC model while additional lines as well as VAr-plants are used as reinforcements to cope with real network requirements. The solution of the reinforcement stage can be obtained by assuming all reactive demands are supplied locally to achieve a solution for AC-TNEP and by neglecting the local reactive sources, a reactive power planning (RPP) will be managed to find the minimum required reactive power sources. Binary GA as well as a real genetic algorithm (RCA) are employed as metaheuristic optimization techniques for solving this combinatorial TNEP as well as the RPP problem. High quality results related with lower investment costs through case studies on test systems show the usefulness of the proposal when working directly with the AC model in transmission network expansion planning, instead of relaxed models. (C) 2010 Elsevier B.V. All rights reserved.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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We present a bilevel model for transmission expansion planning within a market environment, where producers and consumers trade freely electric energy through a pool. The target of the transmission planner, modeled through the upper-level problem, is to minimize network investment cost while facilitating energy trading. This upper-level problem is constrained by a collection of lower-level market clearing problems representing pool trading, and whose individual objective functions correspond to social welfare. Using the duality theory the proposed bilevel model is recast as a mixed-integer linear programming problem, which is solvable using branch-and-cut solvers. Detailed results from an illustrative example and a case study are presented and discussed. Finally, some relevant conclusions are drawn.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The purpose of this study was to evaluate the setting time and the thermal expansion coefficient of 2 endodontic cements, MTA-Angelus and a novel cement called CER. The setting time was determined in accordance to ANSI/ADA specifications no. 57. Three samples of 10 mm diameter and 2 mm thickness were prepared for each cement. The thermal expansion measurements were performed by strain gauge technique. Four samples of each cement were prepared using silicone rings of 5 mm diameter and 2 mm thickness. The data were analyzed statistically using the Student t test. The setting time obtained for the MTA-Angelus and CER cements was 15 (SD 1) min and 7 (SD 1) min, respectively. The linear coefficient of thermal expansion was 8.86 (SD 0.28) mu strain/degrees C for MTA-Angelus and 11.76 (SD 1.20) mu strain/degrees C for CER. The statistical analysis showed significant difference (P < .05) in the setting time and linear coefficient of thermal expansion between the 2 cements. The CER cement has a coefficient of expansion similar to dentin, which could contribute to a decrease of microleakage degree.