926 resultados para Diversity, Innovation, Network Structure, Agglomeration, Biotechnology
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Muitos historiadores afirmam que estamos iniciando uma nova era, a era do conhecimento, da informação, a era digital. Surgem duas grandes armas estratégicas nesse novo ambiente global, para que as empresas sejam competitivas no século vinte e um: a criatividade e a integração. E muitas empresas estão adotando uma nova estrutura organizacional, a estrutura do tipo network, como solução para a gerência da criatividade e da integração. Essa estrutura não se preocupa com novas maneiras de manipular subordinados em vantagem própria. Ao contrário, ela nos desafia a repensar o básico: nossos valores, atitudes e considerações a respeito de liderança, trabalho e tempo. As estruturas hierárquicas convencionais não proporcionam a agilidade de resposta requerida pelo mercado atualmente, devido à burocracia por trás de todas as atividades. As pessoas especializam-se em pequenas atividades, perdendo o sentido do trabalho e a motivação intrínseca. E uma vez que as pessoas são crescentemente reconhecidas como o capital mais importante de qualquer empreendimento, a desmotivação se toma desastrosa para o futuro de qualquer negócio. A reciprocidade empresa-indivíduo é essencial. Esta dissertação pretende analisar o fator humano nos trabalhos realizados dentro da estrutura de network, traçando-se um paralelo entre as propostas dessa estrutura e as necessidades humanas, demonstrando a relação existente entre a estrutura organizacional da criatividade e da integração e a satisfação no trabalho. Iniciamente, apresenta-se uma revisão bibliográfica, sob três diferentes enfoques. Primeiro, explica-se como as transformações mundiais estão afetando a estratégia das empresas. Depois, mostra-se o impacto da estratégia do século vinte e um dentro da organização. Por fim, focaliza-se o lado psicológico do ser humano, suas necessidades, tais quais a autonomia, a competência e o relacionamento interpessoal, os fatores de satisfação intrínsecos e extrínsecos. Assim, pode-se avaliar o impacto de uma nova estrutura organizacional na motivação dos funcionários. A seguir, apresenta-se o projeto de uma pesquisa-piloto dos fatores de satisfação mais relevantes para as pessoas, confirmando-se a importância dos fatores de satisfação intrínsecos. Mostra-se também que os índices de satisfação são diretamente afetados pelo ambiente empresarial onde atuam, de acordo com seu grau de autonomia. Então, são mostradas as conclusões do trabalho e recomendações práticas para mudanças na estrutura organizacional dentro de uma empresa, seus custos e como elas devem ser administradas no longo prazo.
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This work aims to understand the interaction between competition and network formation in the banking market. Combining Matutes and Padilla (1994) and Matutes and Vives (2000), we build a model of imperfect bank competition for deposits in which an interbank relationship network is a key strategic decision: it affects banks’ profit and risk position. The competition level exerts influence in the banking network structure since it affects the network outcomes. As result, we have that different competition levels imply different network topologies. Specifically, greater competition imply denser networks. Finally, when we allow for the possibility of collusion, the denser network can come out in the least competitive environment.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Genetic structure of populations of Rhizoctonia solani anastomosis group-1 IA from soybean in Brazil
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The Basidiomycete fungus Rhizoctonia solani anastomosis group (AG)-1 IA is a major pathogen of soybean in Brazil, where the average yield losses have reached 30 to 60% in some states in Northern Brazil. No information is currently available concerning levels of genetic diversity and population structure for this pathogen in Brazil. A total of 232 isolates of R. solani AG1 IA were collected from five soybean fields in the most important soybean production areas in central-western, northern, and northeastern Brazil. These isolates were genotyped using 10 microsatellite loci. Most of the multilocus genotypes (MLGTs) were site-specific, with few MLGTs shared among populations. Significant population subdivision was evident. High levels of admixture were observed for populations from Mato Grosso and Tocantins. After removing admixed genotypes, three out of five field populations (Maranhao, Mato Grosso, and Tocantins), were in Hardy-Weinberg (HW) equilibrium, consistent with sexual recombination. HW and gametic disequilibrium were found for the remaining soybean-infecting populations. The findings of low genotypic diversity, departures from HW equilibrium, gametic disequilibrium, and high degree of population subdivision in these R. solani AG-1 IA populations from Brazil are consistent with predominantly asexual reproduction, short-distance dispersal of vegetative propagules (mycelium or sclerotia), and limited long-distance dispersal, possibly via contaminated seed. None of the soybean-infecting populations showed a reduction in population size (bottleneck effect). We detected asymmetric historical migration among the soybean-infecting populations, which could explain the observed levels of subdivision.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The genetic diversity of Plasmodium vivax has been investigated in several malaria-endemic areas, including the Brazilian Amazon region, where this is currently the most prevalent species causing malaria in humans. This review summarizes current views on the use of molecular markers to examine P. vivax populations, with a focus on studies performed in Brazilian research laboratories. We emphasize the importance of phylogenetic studies on this parasite and discuss the perspectives created by our increasing understanding of genetic diversity and population structure of this parasite for the development of new control strategies, including vaccines, and more effective drugs for the treatment of P. vivax malaria.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Network reconfiguration is an important tool to optimize the operating conditions of a distribution system. This is accomplished modifying the network structure of distribution feeders by changing the open/close status of sectionalizing switches. This not only reduces the power losses, but also relieves the overloading of the network components. Network reconfiguration belongs to a complex family of problems because of their combinatorial nature and multiple constraints. This paper proposes a solution to this problem, using a specialized evolutionary algorithm, with a novel codification, and a brand new way of implement the genetic operators considering the problem characteristics. The algorithm is presented and tested in a real distribution system, showing excellent results and computational efficiency. © 2007 IEEE.
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To assess the genetic diversity and genetic structure parameters, nine populations of Oryza glumaepatula from the Amazon biome, four from the Pantanal biome, and one collected at Rio Xingu, Mato Grosso, totaling 14 populations and 333 individuals were studied with isozyme markers. Six loci were evaluated showing a moderate allozyme variability (A = 1.21, P = 20.7%, Ho = 0.005, He = 0.060). The populations from the Pantanal biome showed higher diversity levels than the Amazon biome. High genetic differentiation among the populations, expected for self-fertilizing species, was observed (FST=0.763), with lower differentiation found among the Pantanal populations (FST=0.501). The average apparent outcrossing rate was higher for the Pantanal populations (t a = 0.092) than for the Amazonian populations (t a = 0.003), while the average for the 14 populations was 0.047, in accordance with a self-fertilization mating system.
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Estradas cruzando riachos (ou igarapés) por estruturas mal planejadas podem ocasionar alagamentos em segmentos do canal à montante do cruzamento, transformando este trecho de um ambiente lótico em um lêntico. O presente trabalho teve como objetivo estudar a diversidade e a estrutura trófica funcional de comunidades de peixes em alagados de origem antrópica na região nordeste do Pará. Estes alagados são formados pelo cruzamento de estradas sobre a rede fluvial, com maiores ou menores impactos sobre sua conectividade hidrológica, assunto que é largamente ignorado em sistemas lóticos neotropicais. Foram amostrados dezoito trechos de canais em sete igarapés nas bacias dos rios Maracanã e Marapanim, sendo seis deles cruzados por estradas, e um não, como referência. Todos igarapés estão localizados na região nordeste do estado do Pará, sendo cinco nos municípios de Igarapé-Açu e Marapanim, inseridos em uma paisagem agrícola, e dois no município de São Francisco do Pará, inseridos em uma matriz florestal. Dos seis igarapés cruzados por estradas, cinco apresentaram a formação de amplas áreas alagadas. Nestes locais, foram selecionados três trechos do sistema fluvial para amostragem de peixes: um à montante do alagamento, um no próprio alagamento e outro à jusante. No igarapé que não apresentava alagamento, selecionou-se, apenas dois trechos: montante e jusante do cruzamento da estrada sobre o canal. Os ambientes selecionados foram amostrados uma vez, entre junho e novembro de 2010, por técnicas de censo visual, em segmentos de 200 metros de extensão. Foram registradas 73 espécies distribuídas em seis ordens, 26 famílias e 63 gêneros. Characiformes (38,4%) e Siluriformes (31,5%) foram as ordens mais representativas em números de espécies. Characidae, com 15 espécies (20,5%), e Cichlidae, com 10 (13,7%) foram as famílias mais representativas em número de espécies. Estas espécies foram organizadas em 18 grupos tróficos funcionais (GTF), formados de acordo com a tática alimentar observada com maior frequência para cada espécie e sua distribuição espacial observada durante as sessões de mergulho ad libitum. Os alagamentos impuseram modificações na estrutura biótica e física dos igarapés. Estes ambientes apresentaram menor número de espécies, maior abundância e menor diversidade de espécies e de GTF em relação aos trechos à jusante e à montante. Os alagamentos apresentaram maior largura, profundidade e temperatura; e menor velocidade e oxigênio de dissolvido quando comparados aos trechos de igarapés à montante e à jusante. O uso da abordagem de grupos tróficos funcionais facilitou na inferência de como o processo de fragmentação da rede fluvial interfere na estrutura da assembleia de peixes estudada.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Antagonistic interactions between host plants and mistletoes often form complex networks of interacting species. Adequate characterization of network organization requires a combination of qualitative and quantitative data. Therefore, we assessed the distribution of interactions between mistletoes and hosts in the Brazilian Pantanal and characterized the network structure in relation to nestedness and modularity. Interactions were highly asymmetric, with mistletoes presenting low host specificity (i.e., weak dependence) and with hosts being highly susceptible to mistletoe-specific infections. We found a non-nested and modular pattern of interactions, wherein each mistletoe species interacted with a particular set of host species. Psittacanthus spp. infected more species and individuals and also caused a high number of infections per individual, whereas the other mistletoes showed a more specialized pattern of infection. For this reason, Psittacanthus spp. were regarded as module hubs while the other mistletoe species showed a peripheral role. We hypothesize that this pattern is primarily the result of different seed dispersal systems. Although all mistletoe species in our study are bird dispersed, the frugivorous assemblage of Psittacanthus spp. is composed of a larger suite of birds, whereas Phoradendron are mainly dispersed by Euphonia species. The larger assemblage of bird species dispersing Psittacanthus seeds may also increase the number of hosts colonized and, consequently, its dominance in the study area. Nevertheless, other restrictions on the interactions among species, such as the differential capacity of mistletoe infections, defense strategies of hosts and habitat types, can also generate or enhance the observed pattern.
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The amphipod fauna was employed to investigate a bottom environmental gradient in the continental shelf adjacent to Santos Bay. The constant flow of less saline water from the estuarine complex of the Santos and Sao Vicente rivers besides the seasonal intrusion of the cold saline South Atlantic Central Water (SACW) bring a highly dynamic water regime to the area. Density, distribution, diversity and functional structure of the communities were studied on a depth gradient from 10 to 100 m on two cruises in contrasting seasons, winter 2005 and summer 2006. Twenty-one sediment samples were taken with a 0.09m(2) box corer. Temperature and salinity were measured at each station and an additional surface sediment sample was obtained with the box corer for granulometric and chemical analyses. Sixty species were collected on each survey and higher density values were found in summer. A priori one-way Analysis of Similarities (ANOSIM) indicated the existence of three different groups of amphipods related to the depth gradient: the Coastal group, the Mixed Zone group and the Deep Zone group. The Coastal Zone in both cruises was inhabited by a community presenting low diversity and density, besides high dominance of the infaunal tube-dweller Ampelisca paria; the area around 30 m presented the highest values of all the ecological indicators and the species showed several life styles; the outer area, situated between 50 and 100 m depth in the SACW domain, presented a community characterized by lower diversity and high biomass and density values. A season-depth ANOSIM showed the influence of depth and season for the Coastal and Mixed Zone groups whereas no seasonal difference was obtained for the Deep Zone group. The synergistic effect of the SACW and depth in the first place, followed by physical changes in substrate, seem to be the main factors controlling the fauna's distribution. In addition, the estuarine waters from Santos Bay apparently had no effect on the establishment of the environmental gradient observed on the adjacent shelf. Diversity, distribution, functional groups and trophic conditions of superficial sediments are discussed in the light of the main oceanographic processes present on the southern Brazilian shelf.
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Patterns of species interactions affect the dynamics of food webs. An important component of species interactions that is rarely considered with respect to food webs is the strengths of interactions, which may affect both structure and dynamics. In natural systems, these strengths are variable, and can be quantified as probability distributions. We examined how variation in strengths of interactions can be described hierarchically, and how this variation impacts the structure of species interactions in predator-prey networks, both of which are important components of ecological food webs. The stable isotope ratios of predator and prey species may be particularly useful for quantifying this variability, and we show how these data can be used to build probabilistic predator-prey networks. Moreover, the distribution of variation in strengths among interactions can be estimated from a limited number of observations. This distribution informs network structure, especially the key role of dietary specialization, which may be useful for predicting structural properties in systems that are difficult to observe. Finally, using three mammalian predator-prey networks ( two African and one Canadian) quantified from stable isotope data, we show that exclusion of link-strength variability results in biased estimates of nestedness and modularity within food webs, whereas the inclusion of body size constraints only marginally increases the predictive accuracy of the isotope-based network. We find that modularity is the consequence of strong link-strengths in both African systems, while nestedness is not significantly present in any of the three predator-prey networks.
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Financial markets can be viewed as a highly complex evolving system that is very sensitive to economic instabilities. The complex organization of the market can be represented in a suitable fashion in terms of complex networks, which can be constructed from stock prices such that each pair of stocks is connected by a weighted edge that encodes the distance between them. In this work, we propose an approach to analyze the topological and dynamic evolution of financial networks based on the stock correlation matrices. An entropy-related measurement is adopted to quantify the robustness of the evolving financial market organization. It is verified that the network topological organization suffers strong variation during financial instabilities and the networks in such periods become less robust. A statistical robust regression model is proposed to quantity the relationship between the network structure and resilience. The obtained coefficients of such model indicate that the average shortest path length is the measurement most related to network resilience coefficient. This result indicates that a collective behavior is observed between stocks during financial crisis. More specifically, stocks tend to synchronize their price evolution, leading to a high correlation between pair of stock prices, which contributes to the increase in distance between them and, consequently, decrease the network resilience. (C) 2012 American Institute of Physics. [doi:10.1063/1.3683467]