797 resultados para resource curse
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In the last decade mobile wireless communications have witnessed an explosive growth in the user’s penetration rate and their widespread deployment around the globe. It is expected that this tendency will continue to increase with the convergence of fixed Internet wired networks with mobile ones and with the evolution to the full IP architecture paradigm. Therefore mobile wireless communications will be of paramount importance on the development of the information society of the near future. In particular a research topic of particular relevance in telecommunications nowadays is related to the design and implementation of mobile communication systems of 4th generation. 4G networks will be characterized by the support of multiple radio access technologies in a core network fully compliant with the Internet Protocol (all IP paradigm). Such networks will sustain the stringent quality of service (QoS) requirements and the expected high data rates from the type of multimedia applications to be available in the near future. The approach followed in the design and implementation of the mobile wireless networks of current generation (2G and 3G) has been the stratification of the architecture into a communication protocol model composed by a set of layers, in which each one encompasses some set of functionalities. In such protocol layered model, communications is only allowed between adjacent layers and through specific interface service points. This modular concept eases the implementation of new functionalities as the behaviour of each layer in the protocol stack is not affected by the others. However, the fact that lower layers in the protocol stack model do not utilize information available from upper layers, and vice versa, downgrades the performance achieved. This is particularly relevant if multiple antenna systems, in a MIMO (Multiple Input Multiple Output) configuration, are implemented. MIMO schemes introduce another degree of freedom for radio resource allocation: the space domain. Contrary to the time and frequency domains, radio resources mapped into the spatial domain cannot be assumed as completely orthogonal, due to the amount of interference resulting from users transmitting in the same frequency sub-channel and/or time slots but in different spatial beams. Therefore, the availability of information regarding the state of radio resources, from lower to upper layers, is of fundamental importance in the prosecution of the levels of QoS expected from those multimedia applications. In order to match applications requirements and the constraints of the mobile radio channel, in the last few years researches have proposed a new paradigm for the layered architecture for communications: the cross-layer design framework. In a general way, the cross-layer design paradigm refers to a protocol design in which the dependence between protocol layers is actively exploited, by breaking out the stringent rules which restrict the communication only between adjacent layers in the original reference model, and allowing direct interaction among different layers of the stack. An efficient management of the set of available radio resources demand for the implementation of efficient and low complexity packet schedulers which prioritize user’s transmissions according to inputs provided from lower as well as upper layers in the protocol stack, fully compliant with the cross-layer design paradigm. Specifically, efficiently designed packet schedulers for 4G networks should result in the maximization of the capacity available, through the consideration of the limitations imposed by the mobile radio channel and comply with the set of QoS requirements from the application layer. IEEE 802.16e standard, also named as Mobile WiMAX, seems to comply with the specifications of 4G mobile networks. The scalable architecture, low cost implementation and high data throughput, enable efficient data multiplexing and low data latency, which are attributes essential to enable broadband data services. Also, the connection oriented approach of Its medium access layer is fully compliant with the quality of service demands from such applications. Therefore, Mobile WiMAX seems to be a promising 4G mobile wireless networks candidate. In this thesis it is proposed the investigation, design and implementation of packet scheduling algorithms for the efficient management of the set of available radio resources, in time, frequency and spatial domains of the Mobile WiMAX networks. The proposed algorithms combine input metrics from physical layer and QoS requirements from upper layers, according to the crosslayer design paradigm. Proposed schedulers are evaluated by means of system level simulations, conducted in a system level simulation platform implementing the physical and medium access control layers of the IEEE802.16e standard.
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O café é um dos principais produtos agrícolas, sendo considerado o segundo item em importância do comércio internacional de commodities. O gênero Coffea pertence à família Rubiaceae que também inclui outras plantas importantes. Este gênero contém aproximadamente 100 espécies, mas a produção comercial é baseada somente em duas espécies, Coffea arabica e Coffea canephora, que representam aproximadamente 70 % e 30 % do mercado total de café, respectivamente. O Projeto Genoma Café Brasileiro foi desenvolvido com o objetivo de disponibilizar os modernos recursos da genômica à comunidade científica e aos diferentes segmentos da cadeia produtiva do café. Para isso, foram seqüenciados 214.964 clones escolhidos aleatoriamente de 37 bibliotecas de cDNA de C. arabica, C. canephora e C. racemosa representando estádios específicos do desenvolvimento de células e de tecidos do cafeeiro, resultando em 130.792, 12.381 e 10.566 seqüências de cada espécie, respectivamente, após processo de trimagem. Os ESTs foram agrupados em 17.982 contigs e em 32.155 singletons. A comparação destas seqüências pelo programa BLAST revelou que 22 % não tiveram nenhuma similaridade significativa às seqüências no banco de dados do National Center for Biotechnology Information (de função conhecida ou desconhecida). A base de dados de ESTs do cafeeiro resultou na identificação de cerca de 33.000 unigenes diferentes. Os resultados de anotação das seqüências foram armazenados em base de dados online em http://www.lge.ibi.unicamp.br/cafe. Os recursos desenvolvidos por este projeto disponibilizam ferramentas genéticas e genômicas que podem ser decisivas para a sustentabilidade, a competitividade e a futura viabilidade da agroindústria cafeeira nos mercados interno e externo.
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The pressure for a new pattern of sustainable development began to require of modern organizations the conciliation between competitiveness and a environmental protection. In this sense, a tool that acts in the implementation of structured strategies is the Environmental Management System (EMS), which focuses on improving environmental performance. This improvement, in turn, can generate to the organizations many benefits , among which, obtaining competitive advantages, susceptible of measurement from different perspectives. One of these is the application of VRIO model, reasoned by the Resource-Based View (RBV), which considers that differences between companies occurs due to differences between its internal resources and capabilities. However, although was been found some studies in the literature that evaluate the competitive potential of certain organizations , such assessments are not performed on specific objects, like the SEM s. Thus, the aim of this study was to evaluate the resources and capabilities (environmental strategies) adopted by the SGA of the Verdegreen Hotel, identifying which of these have the potential to generate competitive advantage. For this, this exploratory-descriptive character study and delineated as field research and case study was used as data collection tools: a literature survey, semi-structured interviews, document research and participant observation. The interpretation of results and consolidation of information were conducted from a qualitative approach, using two techniques of data analysis, namely: content analysis and analysis through VRIO model. The results show that the hotel is quite structured in relation to their EMS, as well as reaching related to improving the management of environmental factors, strengthening the image and gains in competitiveness benefits. On the other hand, the main difficulties for the implementation of the system are related to employees and suppliers. With regard to environmental strategies adopted, of the 25 strategies identified, 10 showed the potential to generate competitive advantage
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The aim of this article is to analyze the theoretical model proposed by [Jabbour CJC, Santos FCA. Relationships between human resource dimensions and environmental management in companies: proposal of a model. Journal of Cleaner Production 2008;16(1):5 1-8.] based on the data collected in four Brazilian companies. This model investigates how the phases of the environmental management system can be linked to human resource practices in order to attain continuous improvement of a company's environmental performance. Our aim is to contribute to a field, which has little empirical evidence. Although the interaction between the phases of the environmental management system and human resource practices is recommended by the specialized literature [Daily BE Huang S. Achieving sustainability through attention to human resource factors in environmental management. International Journal of Operations and Production Management 2001:21(12):1539-52.], the results indicate that most of the theoretical assumptions could not be confirmed in these Brazilian companies. (C) 2008 Elsevier Ltd. All rights reserved.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Modern techniques for surgical treatment of midfacial and panfacial fractures in maxillofacial trauma lead to special problems for airway management. Usually, in perioperative management of panfacial fractures, the surgeon needs to control the dental occlusion and nasal pyramid assessment. For these reasons, oral and nasal endotracheal intubations are contraindicated for the management of panfacial fractures. Tracheotomy is considered by many as the preferred route for airway management in patients with severe maxillofacial fractures, but there are often perioperative and postoperative complications concerning this technique. The submental route for endotracheal intubation has been proposed as an alternative to tracheotomy in the surgical management of patients with panfacial fractures, besides it is accompanied by low morbidity. Thus, this paper aimed to describe the submental endotracheal intubation technique in a patient experiencing panfacial fracture. The subject was well treated using the submental endotracheal intubation to get good reconstruction of the fractures because the authors obtained free access of all facial fractures.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Parrotfishes are important components of the herbivore and detritivore guilds of tropical and subtropical reefs. Most of parrotfish species are protogynous hermaphrodites that change colour and sex, from initial phase females or males (IP) to terminal phase males (TP). We studied the foraging behaviour of Sparisoma amplum, S. axillare and S. frondosum, three syntopic scarids on the rocky reefs of Fernando de Noronha Archipelago, Tropical West Atlantic. The three parrotfish species differed in food selection and preference, but IP and TP individuals of the same species preferred the same food types, except for S. amplum. Feeding rates of IP individuals were higher than those of TP individuals, but the distribution of feeding frequencies throughout the day of IP and TP individuals of the same species was similar. IP individuals had higher feeding rates than TP ones, which seems related to the fact that TP individuals spend a large amount of time patrolling their territories and chasing away conspecific individuals at the study site. The general foraging pattern we found for S. amplum, S. axillare and S. frondosum is similar to patterns found for other parrotfish species in the Western Atlantic.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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We determined microhabitat and diet niche for tadpoles from two ponds in an agricultural landscape. Additionally, we verified the intraspecific variation in resource use, and if diet and microhabitat use were correlated. Tadpoles found in the two ponds differed in microhabitat use, because in the larger pond they explored deeper places far from the margin. There were three groups with high microhabitat niche overlap. In both ponds, plant cover was the best descriptor to explain interspecific variation in microhabitat use. Tadpoles of all species ingested mainly Bacillariophyceae and Trachellomonas however the diet differed intraspecifically in the species from the two ponds. Ten items in the temporary pond and 15 items in the permanent one were ingested by all species; however, the relative abundance of each item differed. Diet similarity was not correlated to similarity in microhabitat use. In this study, diet was as important as microhabitat use to explain resource partitioning.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)