954 resultados para Random access system


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O objetivo deste trabalho foi avaliar a variabilidade genética de populações de avestruzes (Struthio camelus) por meio de marcadores RAPD (Polimorfismos de DNA amplificado ao acaso). Foram coletadas 121 amostras de indivíduos procedentes dos estados do Pará, Maranhão, Tocantins e Minas Gerais. O DNA genômico foi extraído a partir de sangue total. A triagem de iniciadores permitiu a seleção de 15 entre os 60 analisados que foram amplificados pelo método PCR. Os produtos da PCR foram visualizados em gel de agarose 1,5% e foi gerada uma matriz binária para os fragmentos amplificados com presença (1) e ausência (0) de banda. Para a verificação do número ótimo de bandas polimórficas foi realizada a análise de bootstrap por meio do software GQMOL. Para a análise dos dados foi utilizado o programa NTSYS-pc (Numerical Taxonomy and Multivariate Analysis Sistem), versão 2.02. A similaridade entre as amostras foi analisada através do coeficiente de Jaccard. Foi gerada uma matriz de distância cofenética, usando o módulo Sahncof, do programa NTSYS 2.2. Para realização da estruturação gênica o procedimento empregado foi a análise de variância molecular (AMOVA), processada no software Arlequin 2.0 (Schneider et al., 2000). Os 15 iniciadores geraram um total de 109 bandas polimórficas. A análise de bootstrap mostrou que a partir de 100 bandas o trabalho já se torna mais confiável, uma vez que a magnitude da correlação foi bem próxima do valor máximo (r=0,99), como também a soma de quadrados dos desvios (SQd) atingiu valor baixo 1,25 e o valor do estresse (E) foi de 0,05. Na análise entre pares de grupos, foi verificado que a maior e menor similaridade estão em torno, respectivamente, de 0,86 e 0,00. No que diz respeito à distribuição de freqüência das similaridades obtidas entre os 5.644 pares formados na matriz genética, pode-se verificar que 32,69 % dos pares ficaram incluídos nas classes com similaridades variando de 0,01 a 0,10. Nota-se que a maior porcentagem (85,59%) dos pares ficou distribuídos nas três primeiras classes das extremidades e que a minoria deles (14,41%) apresentou similaridades variando de 0,21 a 1,00. O teste de Mantel mostrou correlação de 0,81 e o dendrograma gerou 67 grupos delimitados pela Sm que foi de 0,49. A maior similaridade foi de 0,86 e a menor de 0,06. Os dados relativos à análise de variância molecular mostraram que a porcentagem de variação genética entre procedências foi baixa e significativa (24,03%, p < 0,0001), evidenciando que grande parte da variação encontra-se dentro das populações (75,97 %). Os marcadores RAPD foram eficientes na caracterização da similaridade genética.

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In this work we study a transmission problem for the model of beams developed by S.P. Timoshenko [10]. We consider the case of mixed material, that is, a part of the beam has friction and the other is purely elastic. We show that for this type of material, the dissipation produced by the frictional part is strong enough to produce exponential decay of the solution, no matter how small is its size. We use the method of energy to prove exponential decay for the solution.

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Equilíbrio líquido-vapor do sistema destilado ácido do óleo de palma-dióxido de carbono a alta pressão. Foi investigado experimentalmente o equilíbrio líquido-vapor para o sistema Destilado Ácido de Óleo de Palma (PFAD)/Dióxido de Carbono, nas temperaturas de 333, 353 e 373 K e pressões de 20, 23, 26 e 29 MPa, usando-se o método estático. Os dados experimentais do sistema pseudo-binário PFAD/CO2 foram correlacionados com a equação de estado de Redlich-Kwong do pacote computacional ASPEN. O modelo reproduz bem os resultados experimentais. A seletividade obtida indica que o CO2 supercrítico é um solvente razoável para a separação em coluna multi-estágio e contínua, do ácido graxo saturado (ácido palmítico) daqueles insaturados (ácido oleico e ácido linoleico) contidos no PFAD.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Environmental monitoring of aquatic systems is an important tool to support policy makers and environmental managers' decisions. Long-term, continuous collection of environmental data is fundamental to the understanding of an aquatic system. This paper aims to present the integrated system for environmental monitoring (SIMA), a long-term temporal series system with a web-based archive for limnological and meteorological data. The following environmental parameters are measured by SIMA: chlorophyll-a (µgL-1), water surface temperature (ºC), water column temperature by a thermistor string (ºC), turbidity (NTU), pH, dissolved oxygen concentration (mg L-1), electric conductivity (µS cm-1), wind speed (ms-1) and direction (º), relative humidity (%), shortwave radiation (Wm-2) and barometric pressure (hPa). The data were collected in a preprogrammed time interval (1 hour) and were transmitted by satellite in quasi-real time for any user within 2500 km of the acquisition point. So far, 11 hydroelectric reservoirs are being monitored with the SIMA buoy. Basic statistics (mean and standard deviation) and an example of the temporal series of some parameters were displayed at a database with web access. However, sensor and satellite problems occurred due to the high data acquisition frequency. Sensors problems occurred due to the environmental characteristics of each aquatic system. Water quality sensors rapidly degrade in acidic waters, rendering the collected data invalid. Data is also rendered invalid when sensors become infested with periphyton. Problems occur with the satellites' reception of system data when satellites pass over the buoy antenna. However, the data transfer at some inland locations was not completed due to the satellite constellation position. Nevertheless, the integrated system of water quality and meteorological parameters is an important tool in understanding the aquatic system dynamic. It can also be used to create hydrodynamics models of the aquatic system to allow for the study of meteorological implications to the water body.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The goal of this study was to evaluate the concentrations of non-structural carbohydrate (NSC) and of total nitrogen (N), as well as, to evaluate the root system in Tanzania-grass pastures fertilized with doses of urea in fall, spring and summer. The experiment was conducted at the Experimental Farm of Iguatemi, Maringa, Parana, Brazil, from March 2007 to March 2008. The experimental design was complete random blocks with subplots and four repetitions. The plots showed doses of N (50, 100 e 150 kg ha(-1) of N) plus the control (no N fertilization), and the subplots the season of the year. Root samples were taken at depths of 0-10, 10-20 and 20-40 cm. Root biomass showed a trend for mass accumulation up to a dosage of 100 kg ha(-1) for all seasons evaluated. Also, about 80% of the root system of Tanzaniagrass plants was found on the 0-10 cm layer for all dosages of N. Nitrogen fertilizer above 100 kg ha(-1) may foster fast forage plant growth reducing its NSC root storage capacity although favoring NSC and total N storage at stem base. NSC and total N concentrations were highest in fall, demonstrating that its usage is greater in spring due to the weather conditions being favorable to plant growth. In the regrowth, the largest reserve of total N was at the 0-10 cm root layer and the largest NSC reserve is at stem base.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Human development and population growth during the twentieth century increased the water demand, tripling its consumption between 1950 and 1990. As the water streams were polluted; and as water is the source of minerals and also regulates vital functions, it becomes the vehicle of transmission and consequently spreads many diseases. Probably, the industries are the major responsible for this pollution when they dump untreated effluents to water streams, saturating the already insufficient net of sanitation facilities polluting water and soil. An effective treatment has been established with low cost in Europe and the United States, through constructed systems on wetlands Constructed Wetland Systems - CWSs, gradually used in other countries in the last three decades. Lately, we observe a continuous growth in Brazilian poultry business, and poultry industry showed greatest dynamism in the country, following the global market. Pondering this information and the efficiency of such treatment, this work aimed to study prototypes, in a laboratory scale, simulating ascending and descending types of CWSs, vegetated with aquatic macrophytes Eichhornia crassipes and the uses of aggregates and soil, to treat industrial wastewater from slaughterhouses and aviary. We conducted the initial characterization of the effluent to have an idea of its constituents and to scale the system and the continuous flow. Furthermore, we characterized the soil to be used in this system. The collects are periodically made in the refrigeration industry FRICOCK FRIGORIFICAÇÃO AVICULTURA INDÚSTRIA E COMÉRCIO LTDA. for local treatment simulation. The effluent that was treated with 12 prototypes of CWSs are analyzed with some frequency. The results of these reviews were compared to the effluent coming from the industry... (Complete abstract click electronic access below)

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Factors influencing the location decisions of offices include traffic, accessibility, employment conditions, economic prospects and land-use policies. Hence tools for supporting real-estate managers and urban planners in such multidimensional decisions may be useful. Accordingly, the objective of this study is to develop a GIS-based tool to support firms who seek office accommodation within a given regional or national study area. The tool relies on a matching approach, in which a firm's characteristics (demand) on the one hand, and environmental conditions and available office spaces (supply) on the other, are analyzed separately in a first step, after which a match is sought. That is, a suitability score is obtained for every firm and for every available office space by applying some value judgments (satisfaction, utility etc.). The latter are powered by a focus on location aspects and expert knowledge about the location decisions of firms/organizations with respect to office accommodation as acquired from a group of real-estate advisers; it is stored in decision tables, and they constitute the core of the model. Apart from the delineation of choice sets for any firm seeking a location, the tool supports two additional types of queries. Firstly, it supports the more generic problem of optimally allocating firms to a set of vacant locations. Secondly, the tool allows users to find firms which meet the characteristics of any given location. Moreover, as a GIS-based tool, its results can be visualized using GIS features which, in turn, facilitate several types of analyses.

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Wireless LAN technology, despite the numerous advantages it has over competing technologies, has not seen widespread deployment. A primary reason for markets not adopting this technology is its failure to provide adequate security. Data that is sent over wireless links can be compromised with utmost ease. In this project, we propose a distributed agent based intrusion detection and response system for wireless LANs that can detect unauthorized wireless elements like access points, wireless clients that are in promiscuous mode etc. The system reacts to intrusions by either notifying the concerned personnel, in case of rogue access points and promiscuous nodes, or by blocking unauthorized users from accessing the network resources.

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Access control is a fundamental concern in any system that manages resources, e.g., operating systems, file systems, databases and communications systems. The problem we address is how to specify, enforce, and implement access control in distributed environments. This problem occurs in many applications such as management of distributed project resources, e-newspaper and payTV subscription services. Starting from an access relation between users and resources, we derive a user hierarchy, a resource hierarchy, and a unified hierarchy. The unified hierarchy is then used to specify the access relation in a way that is compact and that allows efficient queries. It is also used in cryptographic schemes that enforce the access relation. We introduce three specific cryptography based hierarchical schemes, which can effectively enforce and implement access control and are designed for distributed environments because they do not need the presence of a central authority (except perhaps for set- UP).