956 resultados para Radioactive pollution of the atmosphere.


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The Pierre Auger Observatory is a hybrid detector for ultra-high energy cosmic rays. It combines a surface array to measure secondary particles at ground level together with a fluorescence detector to measure the development of air showers in the atmosphere above the array. The fluorescence detector comprises 24 large telescopes specialized for measuring the nitrogen fluorescence caused by charged particles of cosmic ray air showers. In this paper we describe the components of the fluorescence detector including its optical system, the design of the camera, the electronics, and the systems for relative and absolute calibration. We also discuss the operation and the monitoring of the detector. Finally, we evaluate the detector performance and precision of shower reconstructions. (C) 2010 Elsevier B.V All rights reserved.

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The impact of human activity on the sediments of Todos os Santos Bay in Brazil was evaluated by elemental analysis and (13)C Nuclear Magnetic Resonance ((13)C NMR). This article reports a study of six sediment cores collected at different depths and regions of Todos os Santos Bay. The elemental profiles of cores collected on the eastern side of Frades Island suggest an abrupt change in the sedimentation regime. Auto-regressive Integrated Moving Average (ARIMA) analysis corroborates this result. The range of depths of the cores corresponds to about 50 years ago, coinciding with the implantation of major onshore industrial projects in the region. Principal Component Analysis of the (13)C NMR spectra clearly differentiates sediment samples closer to the Subae estuary, which have high contents of terrestrial organic matter, from those closer to a local oil refinery. The results presented in this article illustrate several important aspects of environmental impact of human activity on this bay. (C) 2011 Elsevier Ltd. All rights reserved.

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This work presents results of studies of carbon-dispersed Pt-Rh (1:1) nanoparticles as electrocatalysts for the ethanol electro-oxidation. The influences of the crystallite size and the cell temperature on the yields of CO2, acetaldehyde and acetic acid are investigated. Metal nanoparticles were prepared by two different routes: (1) impregnation on carbon powder followed by thermal reduction on hydrogen atmosphere and (2) chemical reduction of the precursor salts. The surface active area and the electrochemical activity of the electrocatalysts were estimated by CO stripping and cyclic voltammetry in the absence and in the presence of ethanol, respectively. Reaction intermediates and products were analyzed by in situ Fourier Transform Infra-Red Spectroscopy (FTIR) and Differential Electrochemical Mass Spectrometry (DEMS). The electrochemical stripping of CO and the electrochemical ethanol oxidation were slightly faster on the Pt-Rh electrocatalysts compared to Pt/C. Also, in situ FTIR spectra and DEMS measurements evidenced that the CO2/acetaldehyde and the CO2/acetic acid ratios are higher for the Pt-Rh/C materials in relation to Pt/C. This was ascribed to the activation of the C-C bond breaking by Rh, this being more prominent for the materials with smaller crystallite sizes. (C) 2008 Elsevier B.V. All rights reserved.

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Purpose – The purpose of this paper is to identify the expectations of the workingGerman Generation Y regarding its current work and employer. As a result, the mainelements which could be considered by companies to retain the Generation Y inGermany will be pointed out and discussed.Design/methodology/approach – Semi-structured interviews were used in order toexplore the work expectations of this young generation within a German company. Anon-probability and purposive sample was used and six respondents part of theGeneration Y and working in the same company were interviewed. Furthermore, aseventh interview was conducted with the HMR of the company.Findings – Several findings are consistent with previous results of Gen Y from othernationalities than Germany such as the importance of varied tasks, opportunities forself-development, responsibilities and a pleasant working atmosphere. However,differences were found in particular regarding the importance of the work-life balanceand new expectations such as trust, autonomy and internationality have been broughtto light. Furthermore, several findings are also consistent with other studies aboutemployee retention, commitment and job satisfaction.Originality/value – This research extended previous studies of the expectations of theGeneration Y by providing firstly findings for Germany, a country where such studieshave not been conducted yet and secondly by focusing on the Generation Y who isalready working and therefore not studying anymore.

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Maine sporting camps were a cultural and social phenomenon of the urban upper and middle class. They originated in Maine in the late 1870s and early 1880s and reached their zenith around the turn of the century with over 160 in operation in eight of the sixteen counties in Maine in 1906. The period from 1880 until World War I can be considered the 'golden era' of the Maine sporting camps. After the war, with technological advancements such as the outboard motor, the proliferation of the automobile, and the introduction of a road system into rural Maine, the camps underwent significant change that warrants an entirely different cultural analysis. A number of elements came together to produce a cultural atmosphere permissive of sporting camp creation in Maine. These include changing national views upon nature, health, sport and the leisure time in which to pursue them. In the late nineteenth century, with the rise of large industrially based cities, overcrowding fostered crime and disease. An upper and middle class emerged that desired escape and separation from the lower classes. Maine was chosen for such an escape because it offered, through sporting camps, a chance to "get back to nature," by pursuing the healthful activities of hunting and fishing. At the same time these urban sportsmen and sportswomen distinguished themselves on the social Hierarchical scale from the rural inhabitants. What happened in rural Maine during the period between 1880 and World War I was the introduction of a new cultural order on the landscape. Coming primarily from urban centers on the East Coast of the United States were men, women and children who looked to Maine for vacations. These vacations were designed to put them in touch with nature by pursuing healthful activities, especially those of fishing and hunting. Coming from an environment that emphasized social standing, they ensured that these trips would perpetuate this hierarchy. They experienced nature through the Maine sporting camps, which provided them with the services and skills necessary to experience it while enjoying a degree of luxury that they were accustomed to in the urban world. The Maine sporting camps were a cultural manifestation of the urban upper and middle class, the groups that the camps were established to serve. Despite this the camps did not represent a structural duplication of urban society. Instead, the camps represented a cultural construction that was produced by interaction between members of two different conceptual and physical worlds, the blending of which, on a social level, was determined by urban mentality and rural knowledge. In the production of a cultural world meaningful to the clients, the rural world of the Maine woods was altered to meet their needs. It was not a one-sided process, however, as the clients were forced to acknowledge the importance of the rural inhabitants on the basis of their value to the clients.

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This study will collaborate by bringing some detailed analysis and findings on a special case study of a discontinuous product development process, trying to answer how the discontinuous product development process takes place and the main factors that influence this process. Additionally, it tried to explore some explanations for the difficulties generally faced by the companies to sustain innovation. The case is about the Motorola cell phone RAZR V3, launched in 2004. RAZR V3 was noted by industry experts as game-changing feat of design and engineering, selling more than 110 million units by end of 2008 and recognized as one of the fastest selling products in the industry. The study uses a single case methodology, which is appropriate given the access to a phenomenon that happened inside corporate dominium and it is not easily accessed for academic studies, besides being a rare case of success in the cellular phone industry. In order to magnify the understanding of the phenomenon, the exploration was extended to contrast the RAZR development process and the standard product development process in Motorola. Additionally, it was integrated a longitudinal reflection of the company product development evolution until the next breakthrough product hitting the cellular phone industry. The result of the analysis shows that discontinuous products do not fit well traditional product development process (in this case, stage-gate). This result reinforces the results obtained on previous studies of discontinuous product development conducted by other authors. Therefore, it is clear that the dynamics of discontinuous product development are different from the continuous product development, requiring different treatment to succeed. Moreover, this study highlighted the importance of the management influence in all the phases of the process as one of the most important factors, suggesting a key component to be carefully observed in future researches. Some other findings of the study that were considered very important for a discontinuous product development process: have champions (who believe and protect the project) and not only one champion; create a right atmosphere to make flow the creative process; question paradigms to create discontinuous products; simple guiding light to focus the team; company culture that accepts and knows how to deal with risks; and undoubtedly, have a company strategy that understands the different dynamics of continuous and discontinuous product development processes and treat them accordingly.

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A method for the simultaneous determination of major and minor volatiles composition in different types (dry, medium dry, sweet and medium sweet) of a young Tinta Negra Mole (TNM) monovarietal red wine from 2003 harvest has been validated. Wine samples preparation includes a dichloromethane liquid–liquid extraction followed by concentration under a nitrogen atmosphere. The extracted fraction was analysed by gas chromatography–mass spectrometry and give quantitative information for more than 86 analytes whose concentration range from few μg l−1 to 259.1 mg l−1. The method enables high recovery of volatile compounds in wine good linearity with (r2) values higher than 0.980 and good sensitivity. The limits of detection range from 0.003 to 0.534 mg l−1 and limits of quantification from 0.009 to 1.170 mg l−1. The method allows satisfactory determination of more than 80 compounds in the TNM red wines. These wines are characterized by a high content of higher alcohols, ethyl esters, fatty acids and lactones. The levels of sulphur compounds in Tinta Negra Mole medium sweet wines are very low, but they have the highest concentration of carbonyl compounds. Quantitative analysis of the main odorants followed by the determination of aroma index allow us elucidate the aroma of these varieties. On the basis of their odour description and odour threshold, the most powerful odorants of Tinta Negra Mole wines were tentatively established.

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PURPOSE: To evaluate if the ileum resection changes the functioning liver cell mass, the hepatic metabolism and the biodistribution of radiopharmaceutical in rats. METHODS: Twelve Wistar rats weighing 285g±34g were randomly divided into the ileum resection group (n = 6) and sham group rats (n = 6). After 30 days, they were anesthetized and 0.1mL of 99m-Tc-phytate(0.66MBq) was injected via femoral vein. After 30 minutes, blood samples were collected for red blood cells radioactive labeling and serum ALT, AST and gammaGT. Liver samples were used for 99m-Tc-phytatepercentage of radioactivity/gram of tissue and histopathology. Student’s t test was used with significance 0.05. RESULTS: There was a higher uptake of 99m-Tc-phytate in the liver of sham rats, compared to the ileum resection group (p<0.05). GammaGT, ALT and AST were increased in ileum resection rats compared to sham (p<0.05). The he patocytes count was significantly lower in ileum resection group than in sham (p<0.05). Liver: body mass ratio was lower in experimental animals than in sham group (p<0.05). CONCLUSION: These data support that the ileum has important role in liver function and liver mass regulation, and they have potential clinical implications regarding the pathogenesis of liver injury following lower bowel resection.

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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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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)