942 resultados para Medium access control
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Tese apresentada como requisito parcial para obtenção do grau de Doutor em Gestão de Informação
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Dissertação para obtenção do Grau de Mestre em Engenharia Informática
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Saccharomyces cerevisiae as well as other microorganisms are frequently used in industry with the purpose of obtain different kind of products that can be applied in several areas (research investigation, pharmaceutical compounds, etc.). In order to obtain high yields for the desired product, it is necessary to make an adequate medium supplementation during the growth of the microorganisms. The higher yields are typically reached by using complex media, however the exact formulation of these media is not known. Moreover, it is difficult to control the exact composition of complex media, leading to batch-to-batch variations. So, to overcome this problem, some industries choose to use defined media, with a defined and known chemical composition. However these kind of media, many times, do not reach the same high yields that are obtained by using complex media. In order to obtain similar yield with defined media the addition of many different compounds has to be tested experimentally. Therefore, the industries use a set of empirical methods with which it is tried to formulate defined media that can reach the same high yields as complex media. In this thesis, a defined medium for Saccharomyces cerevisiae was developed using a rational design approach. In this approach a given metabolic network of Saccharomyces cerevisiae is divided into a several unique and not further decomposable sub networks of metabolic reactions that work coherently in steady state, so called elementary flux modes. The EFMtool algorithm was used in order to calculate the EFM’s for two Saccharomyces cerevisiae metabolic networks (amino acids supplemented metabolic network; amino acids non-supplemented metabolic network). For the supplemented metabolic network 1352172 EFM’s were calculated and then divided into: 1306854 EFM’s producing biomass, and 18582 EFM’s exclusively producing CO2 (cellular respiration). For the non-supplemented network 635 EFM’s were calculated and then divided into: 215 EFM’s producing biomass; 420 EFM’s producing exclusively CO2. The EFM’s of each group were normalized by the respective glucose consumption value. After that, the EFMs’ of the supplemented network were grouped again into: 30 clusters for the 1306854 EFMs producing biomass and, 20 clusters for the 18582 EFM’s producing CO2. For the non-supplemented metabolic network the respective EFM’s of each metabolic function were grouped into 10 clusters. After the clustering step, the concentrations of the other medium compounds were calculated by considering a reasonable glucose amount and by accounting for the proportionality between the compounds concentrations and the glucose ratios. The approach adopted/developed in this thesis may allow a faster and more economical way for media development.
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Introduction Hepatitis C virus (HCV) is primarily transmitted via contact with the blood of infected patients, although the form of contact has not been identified for a significant percentage of carriers. The present study evaluated possible risk factors for HCV transmission in a medium-sized town located in the northwest region of the State of São Paulo. Methods This was a case-control study, with the case group consisting of 190 chronic HCV carriers older than 18 years residing in the municipality of Catanduva. The control group also consisted of 190 individuals with HCV-negative serology. The groups were paired (1:1) for gender, age range (± five years), and place of residence. The same structured questionnaire was applied to all subjects, who gave written informed consent to participate in the study. The data were statistically analyzed using crude and adjusted logistic regression, and the results were expressed as odds ratios with a 95% confidence interval. Results The demographic profiles of the groups indicated a predominance of males (68.9%) and mean ages of 47.1 years (case group) and 47.3 years (control group). After adjusting for conditional regression, the following factors were found to represent risks for HCV: history of sexually transmitted disease (STD) and blood transfusion; accidents with syringes and/or needles; tattoos; and the use of non-injectable drugs and injectable medications. Conclusions The transmission of HCV via the blood route has been well characterized. Other forms of contact with human blood and/or secretions are likely to transmit the virus, although with a lower frequency of occurrence.
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Madine Darby Canine Kidney (MDCK) cell lines have been extensively evaluated for their potential as host cells for influenza vaccine production. Recent studies allowed the cultivation of these cells in a fully defined medium and in suspension. However, reaching high cell densities in animal cell cultures still remains a challenge. To address this shortcoming, a combined methodology allied with knowledge from systems biology was reported to study the impact of the cell environment on the flux distribution. An optimization of the medium composition was proposed for both a batch and a continuous system in order to reach higher cell densities. To obtain insight into the metabolic activity of these cells, a detailed metabolic model previously developed by Wahl A. et. al was used. The experimental data of four cultivations of MDCK suspension cells, grown under different conditions and used in this work came from the Max Planck Institute, Magdeburg, Germany. Classical metabolic flux analysis (MFA) was used to estimate the intracellular flux distribution of each cultivation and then combined with partial least squares (PLS) method to establish a link between the estimated metabolic state and the cell environment. The validation of the MFA model was made and its consistency checked. The resulted PLS model explained almost 70% of the variance present in the flux distribution. The medium optimization for the continuous system and for the batch system resulted in higher biomass growth rates than the ones obtained experimentally, 0.034 h-1 and 0.030 h-1, respectively, thus reducing in almost 10 hours the duplication time. Additionally, the optimal medium obtained for the continuous system almost did not consider pyruvate. Overall the proposed methodology seems to be effective and both proposed medium optimizations seem to be promising to reach high cell densities.
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Several studies have shown that people with disabilities benefit substantially from access to a means of independent mobility and assistive technology. Researchers are using technology originally developed for mobile robots to create easier to use wheelchairs. With this kind of technology people with disabilities can gain a degree of independence in performing daily life activities. In this work a computer vision system is presented, able to drive a wheelchair with a minimum number of finger commands. The user hand is detected and segmented with the use of a kinect camera, and fingertips are extracted from depth information, and used as wheelchair commands.
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The distribution of the nests of Podocnemis expansa (Amazon turtle) and Podocnemis unifilis (yellow-spotted side neck turtle) along the point bars of the Javaés River in Bananal Island, demonstrates a clear preference of these chelonians for differentiated geological environments, in respect to the morphology, grain size or height of the nests in relation to the level of the river. The topographical distribution and the differences in the grain size of the sediments that compose the point bars of the river, originated from the multiple sedimentary processes, and make possible the creation and separation of different nesting environments. Each turtle species takes advantage of the place that presents physiographic characteristics appropriate to the hatching success of their eggs. The superposition of the P. expansa and P. unifilis nest placement areas is rare. The P. expansa nests are concentrated on the central portion of the beaches where successive depositional sedimentary events produced sandy banks more than 3.3 m above the river water level. The P. unifilis nests are distributed preferentially in the upstream and downstream portions along the point bars where the sandy deposits rarely surpass 1.5 m at the moment of laying. P. expansa nests located on the beaches of fine to medium sized sand hatch in a mean of 68 days, while those incubated on beaches of medium to coarse sand size take a mean of 54 days to hatch.
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Dairy sludge generated at Glanbia Ingredients Ltd., Kilkenny has up until now been landspread. This study investigated the feasibility of using earthworms to vermicompost the sludge as an alternative method of treatment. It was found that high levels of ammonia in the sludge led to earthworm fatality but that by manually aerating the sludge the ammonia could be volatilised or by adding zeolite the ammonia could be absorbed, thus solving the problem. In a medium scale trial, the earthworm species Dendrobaena veneta and Eisenia fetida dominated the polyculture. Earthworms grew and generated cocoons during vermicomposting. During vermicomposting no leachate was generated. Nutrient changes took place during vermicomposting. There were high levels of nitrate, increased calcium and sulphate in the vermicomposted dairy sludge. The amount of magnesium, potassium and chloride did not change, while phosphate was undetectable after vermicomposting. The levels of nitrate and phosphate were good indicators of the extent of vermicomposting. The vermicomposted dairy sludge provided improved growth and yields of radishes and barley compared to the dairy sludge and control. Compared to the vermicompost, the dairy sludge provided heavier ryegrass yields and more marigolds with larger flower diameters. Generally, it is the amount of phosphate in dairy sludge that dictates how much can be applied as a fertiliser on land. Vermicomposting reduced the amount of phosphate to an undetectable level but on the other hand created a problem of high nitrate levels. In a pot trial with grass grown in vermicompost the nitrate leached from the vermicompost. In field conditions the leaching of nitrate might occur and could cause an increased risk of contamination of groundwater and watercourses.
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Patients who develop a severe stenosis in biological pulmonary conduits previously implanted for pulmonary outflow trunk reconstructions are treated either by surgical re-replacement, or by transcatheter stent-valve implantation through a femoral vein access. A catheter-based sub-xyphoidian access through the right ventricle for stent-valve positioning in a pulmonary conduit has rarely been proposed. We describe the case of a 20-year-old man who underwent a pulmonary trunk reconstruction for a congenital pulmonary valve dysplasia and a few years later developed a stenosis in the pulmonary conduit. He was successfully treated with a 23 mm Edwards Sapien stent-valve implantation in pulmonary position, through an unusual right ventricular, sub-xyphoidian access and without contrast medium injections and pleura opening.
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The subject of this conference reflects the scientific community's interest in seeking to understand the complex causal web whose various social, economic, and biological components interact in the production and reproduction of schistosomiasis and its control in relation to community participation. From the onset, the author stresses the impossibility of dealing separately with community participation, as if social components were just one more "weapon" in the arsenal for schistosomiasis control. This study begins with a brief historical review of the 71 years of control activities with this endemic disease, stressing the enormous efforts and huge expenditures in this field vis-à-vis the limited results, despite the extraordinary technological development of specific, classical control inputs such as new treatment drugs and molluscicides. The article then discusses the various strategies used in control programs, emphasizing ideological consistencies and contradictions. Interactions at the macro and micro levels are discussed, as are the determinants and risk factors involved in producing the disease's endemicity. Unequal occupation of space leaves the segregated portion of the population exposed to extremely favorable conditions for transmission of the disease. This raises the issue of how to control an endemic disease which is so closely linked to the way of life imposed on the population. The study challenges the classical control model and suggests an alternative model now undergoing medium-term investigation in the States of Espirito Santo, and Pernambuco, Brazil. The author concludes that we do not need new strategies, but a new control model, contrary to the prevailing classical model in both concept and practice. From the conceptual point of view, the new model mentioned above is different from others in that schistosomiasis control is seen from a social perspective stressing the population's accumulated knowledge in addition to the building of shared knowledge. The model's praxis has the following characteristics: (1) it is integrated with and financed by research agencies and health services; (2) it operates at the local health services level; (3) use of molluscicides has been eliminated; (4) emphasis is given to individual medical treatment and improvement of sanitary conditions.
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Evolutionary theory may contribute to practical solutions for control of disease by identifying interventions that may cause pathogens to evolve to reduced virulence. Theory predicts, for example, that pathogens transmitted by water or arthropod vectors should evolve to relatively high levels of virulence because such pathogens can gain the evolutionary benefits of relatively high levels of host exploitation while paying little price from host illness. The entrance of Vibrio cholerae into South America in 1991 has generated a natural experiment that allows testing of this idea by determining whether geographic and temporal variations in toxigenicity correspond to variation in the potential for waterborne transmission. Preliminary studies show such correspondences: toxigenicity is negatively associated with access to uncontaminated water in Brazil; and in Chile, where the potential for waterborne transmission is particularly low, toxigenicity of strains declined between 1991 and 1998. In theory vector-proofing of houses should be similarly associated with benignity of vectorborne pathogens, such as the agents of dengue, malaria, and Chagas' disease. These preliminary studies draw attention to the need for definitive prospective experiments to determine whether interventions such as provisioning of uncontaminated water and vector-proofing of houses cause evolutionary reductions in virulence
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In 1975 the Special Programme for Schistosomiasis Control was introduced in Brazil with the objective of controlling this parasitic disease in six northeastern states. The methodology applied varied largely from state to state, but was based mainly on chemotherapy, This Programme was modified about ten years after it beginning with the main goals including control of morbidity and the blockage of establishment of new foci in non-endemic areas. In two states, Bahia and Minas Gerais, the schistosomiasis control programme started in 1979 and 1983, respectively. The recently made evaluation of those two programmes is the main focus of this paper. It must also be pointed out, that the great majority of the studies performed by different researchers in Brazil, at different endemic areas, consistently found significant decrease on prevalence and incidence, when control measures are repeatedly used for several years. Significant decrease of hepatosplenic forms in the studied areas is well documented in Brazil. After more than 20 years of schistosomiasis control programmes in our country, chemotherapy has shown to be a very important tool for the control of morbidity and to decrease prevalence and incidence in endemic areas. Nevertheless, in medium and long terms, sanitation, water supply, sewage draining and health education seem to be the real tools when the aim is persistent and definitive schistosomiasis control.
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Synthesis of polyhydroxyalkanoates (PHAs) from intermediates of fatty acid beta-oxidation was used as a tool to study fatty acid degradation in developing seeds of Arabidopsis. Transgenic plants expressing a peroxisomal PHA synthase under the control of a napin promoter accumulated PHA in developing seeds to a final level of 0. 06 mg g(-1) dry weight. In plants co-expressing a plastidial acyl-acyl carrier protein thioesterase from Cuphea lanceolata and a peroxisomal PHA synthase, approximately 18-fold more PHA accumulated in developing seeds. The proportion of 3-hydroxydecanoic acid monomer in the PHA was strongly increased, indicating a large flow of capric acid toward beta-oxidation. Furthermore, expression of the peroxisomal PHA synthase in an Arabidopsis mutant deficient in the enzyme diacylglycerol acyltransferase resulted in a 10-fold increase in PHA accumulation in developing seeds. These data indicate that plants can respond to the inadequate incorporation of fatty acids into triacylglycerides by recycling the fatty acids via beta-oxidation and that a considerable flow toward beta-oxidation can occur even in a plant tissue primarily devoted to the accumulation of storage lipids.
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Sistemas empotrados (embedded system).Monitorización y control de sensores inalámbricos.El sistema provee monitorización y control remoto vía internet y telefonía móvil además de acceso local y registros en base de datos.Dotado de un actuador físico para el control de elementos de potencia.
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Aquest treball de final de carrera consisteix en l'anàlisi, disseny i implementació d'una aplicació web distribuïda per controlar l'estat horari dels treballadors d'una empresa. L'enginyeria d'aquest programari està basada en el paradigma d'orientació a objectes dins l'estàndard UML; la implementació s'ha fet en llenguatge Java i s'ha utilitzat l'arquitectura J2EE. L'aplicació resultant segueix principalment el patró arquitectònic Model Vista Controlador (MVC) utilitzant el framework Struts2 i el patró Data Access Object (DAO) per a la persistència de dades amb Hibernate 3.