Spatial expansion and population structure of the neotropical malaria vector, Anopheles darlingi (Diptera: Culicidae)

Extensive population structuring is known to occur in Anopheles darlingi, the primary malaria vector of the Neotropics. We analysed the phylogeographic structure of the species using the mitochondrial cytochrome oxidase I marker. Diversity is divided into six main population groups in South America: Colombia, central Amazonia, southern Brazil, south-eastern Brazil, and two groups in north-east Brazil. The ancestral distribution of the taxon is hypothesized to be central Amazonia, and there is evidence of expansion from this region during the late Pleistocene. The expansion was not a homogeneous front, however, with at least four subgroups being formed due to geographic barriers. As the species spread, populations became isolated from each other by the Amazon River and the coastal mountain ranges of south-eastern Brazil and the Andes. Analyses incorporating distances around these barriers suggest that the entire South American range of An. darlingi is at mutation-dispersal-drift equilibrium. Because the species is distributed throughout such a broad area, the limited dispersal across some landscape types promotes differentiation between otherwise proximate populations. Moreover, samples from the An. darlingi holotype location in Rio de Janeiro State are substantially derived from all other populations, implying that there may be additional genetic differences of epidemiological relevance. The results obtained contribute to our understanding of gene flow in this species and allow the formulation of human mosquito health protocols in light of the potential population differences in vector capacity or tolerance to control strategies. (C) 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 854-866.

Toll-Like Receptor 4 Signaling Leads to Severe Fungal Infection Associated with Enhanced Proinflammatory Immunity and Impaired Expansion of Regulatory T Cells

Toll-like receptors (TLRs) present in innate immune cells recognize pathogen molecular patterns and influence immunity to control the host-parasite interaction. The objective of this study was to characterize the involvement of TLR4 in the innate and adaptive immunity to Paracoccidioides brasiliensis, the most important primary fungal pathogen of Latin America. We compared the responses of C3H/HeJ mice, which are naturally defective in TLR4 signaling, with those of C3H/HePas mice, which express functional receptors, after in vitro and in vivo infection with P. brasiliensis. Unexpectedly, we verified that TLR4-defective macrophages infected in vitro with P. brasiliensis presented decreased fungal loads associated with impaired synthesis of nitric oxide, interleukin-12 (IL-12), and macrophage chemotactic protein 1 (MCP-1). After intratracheal infection with 1 million yeasts, TLR4-defective mice developed reduced fungal burdens and decreased levels of pulmonary nitric oxide, proinflammatory cytokines, and antibodies. TLR4-competent mice produced elevated levels of IL-12 and tumor necrosis factor alpha (TNF-alpha), besides cytokines of the Th17 pattern, indicating a proinflammatory role for TLR4 signaling. The more severe infection of TLR4-normal mice resulted in increased influx of activated macrophages and T cells to the lungs and progressive control of fungal burdens but impaired expansion of regulatory T cells (Treg cells). In contrast, TLR4-defective mice were not able to clear their diminished fungal burdens totally, a defect associated with deficient activation of T-cell immunity and enhanced development of Treg cells. These divergent patterns of immunity, however, resulted in equivalent mortality rates, indicating that control of elevated fungal growth mediated by vigorous inflammatory reactions is as deleterious to the hosts as low fungal loads inefficiently controlled by limited inflammatory reactions.

Plasmodium falciparum Accompanied the Human Expansion out of Africa

Plasmodium falciparum is distributed throughout the tropics and is responsible for an estimated 230 million cases of malaria every year, with a further 1.4 billion people at risk of infection [1-3]. Little is known about the genetic makeup of P. falciparum populations, despite variation in genetic diversity being a key factor in morbidity, mortality, and the success of malaria control initiatives. Here we analyze a worldwide sample of 519 P. falciparum isolates sequenced for two housekeeping genes (63 single nucleotide polymorphisms from around 5000 nucleotides per isolate). We observe a strong negative correlation between within-population genetic diversity and geographic distance from sub-Saharan Africa (R(2) = 0.95) over Africa, Asia, and Oceania. In contrast, regional variation in transmission intensity seems to have had a negligible impact on the distribution of genetic diversity. The striking geographic patterns of isolation by distance observed in P. falciparum mirror the ones previously documented in humans [4-7] and point to a joint sub-Saharan African origin between the parasite and its host. Age estimates for the expansion of P. falciparum further support that anatomically modern humans were infected prior to their exit out of Africa and carried the parasite along during their colonization of the world.

Expansion of CD4(+) CD25(+) Foxp3(+) T cells by bone marrow-derived dendritic cells

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.

Iodine(III)-promoted ring expansion of 1-vinylcycloalkanol derivatives: A metal-free approach toward seven-membered rings

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.

Verksamhetsanalys vid ett snickeriföretag – behov av organisationsanpassningvid expansion

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.

Electric Power Service Areas, Energy Lines, and Hydroelectric Dams of Maine

http://digitalcommons.colby.edu/atlasofmaine2008/1010/thumbnail.jpg

The drivers for entry and expansion modes of U.S.- based MNES in Brazil

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.

Uma análise histórico-comparativa dos modelos de financiamento dos empreendimentos hidrelétricos de Xingó e Santo Antônio

O objetivo deste estudo histórico-comparativo é verificar a apropriação pelo setor elétrico, mais especificamente no segmento de geração de energia elétrica, das inovações financeiras disponibilizadas para o financiamento de empresas, difundidas a partir da década de 80, mediante levantamento da legislação balizadora da atuação das concessionárias do setor e conectá-las à forma utilizada de seu financiamento na expansão da geração hidrelétrica. Para isso, utiliza-se da comparação das Usinas Hidrelétricas de Xingó e Santo Antônio, de porte equivalentes, concedidas para a exploração hidráulica em períodos distintos e separadas por um período de alteração de modelo regulatório, compreendido entre 1988 e 2004. A análise e comparação das características das usinas consideradas relevantes para o estudo: empreendimento, sociedade, remuneração, forma e fontes de financiamento, permitiram identificar as distinções nessas características e suas vinculações com a regulamentação setorial e diretrizes da forma de gestão adotada pelo estado em cada período, além do alinhamento societário para a utilização das inovações financeiras na captação de recursos destinados aos investimentos de geração do setor.

Growing research where economies grow: essays on strategy and international expansion of companies from emerging countries

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.

Entry and externality : hydroelectric generators in Brazil

This work analyzes the entry problem in the hydroelectric generation industry. The operation of a generator upstream regularizes the river flow for generators located downstream on the same river, increasing the production capacity of the latter. This positive externality increases the attractiveness of the locations downstream whenever a generator decides to enter upstream. Therefore, the entry decision of a generator in a given location may affect all entry decisions in potential locations for plants downstream. I first model the problem of generators located in cascade on the same river to show the positive effect of the externality. Next, I develop a method to estimate an entry model specific to the hydro generation industry which takes into account the externality of the entry decisions. Finally, I use a data set on investment decisions of Brazilian hydro-generators to estimate the model. The results show a positive incentive to locate downstream from existing plants and from locations where entry is likely to occur. An interesting by-product of the analysis is that the year effects’ estimates show an increase one year before the energy crisis of 2001, providing evidence that the market anticipated the crisis. It contradicts the governmental version that the crisis was due to an unexpected drought.

The Panama canal expansion mega project : a case study and stakeholder´s analysis

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.

Cryptic lineages and Pleistocene population expansion in a Brazilian Cerrado frog

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Transmission system expansion planning by an extended genetic algorithm

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.