Indirect optical transitions from carriers trapped on the delta doping and on the parabolic quantum well

In this work, doped AlGaAs/GaAs parabolic quantum wells (PQW) with different well widths (from 1000 angstrom up to 3000 angstrom) were investigated by means of photoluminescence (PL) measurements. In order to achieve the 2DEG inside the PQW Si delta doping is placed at both side of the well. We have observed that the thickness of this space layer plays a major rule on the characteristics of the 2DEG. It has to be thicker enough to prevent any diffusions of Si to the well and thin enough to allow electrons migration inside the well. From PL measurement, we have observed beside the intra well transitions, indirect transitions involving still trapped electron on the delta doping and holes inside the PQW. For the thinness sample, we have measured a well defined PL peak at low energy side of the GaAs bulk emission. With the increasing of the well thickness this peak intensity decreases and for the thickest sample it almost disappears. Our theoretical calculation indicated that carriers (electron and holes) are more placed at the center of the PQW. In this way, when the well thickness increases the distance between electrons on the delta doping and holes on the well also increases, it decreases the probability of occurrence of these indirect optical transitions. (C) 2012 Published by Elsevier B.V. Selection and/or peer-review under responsibility of Universidade Federal de Juiz de Fora, Brazil.

Mercury and DDT exposure risk to fish-eating human populations in Amazon

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Determination of the numerical parameters of a continuous damage model for the structural analysis of clay brick masonry

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

HELMINTH FAUNA of TWO GECKO LIZARDS, HEMIDACTYLUS AGRIUS and LYGODACTYLUS KLUGEI (GEKKONIDADE), FROM CAATINGA BIOME, NORTHEASTERN BRAZIL.

This study presented data on helminth fauna of two gecko lizards, Hemidactylus agrius and Lygodactylus klugei, from Caatinga biome in northeastern Brazil. It was found four helminth species parasitizing H. agrius, cistacanth of Centrorhynchidae (Acanthocephala) and the nematodes Physalopteridae (larvae), Parapharyngodon alvarengai (Pharyngodonidae) and Skrjabinelazia sp. (Seuratidade). The host Lygodactylus klugei presented two helminth species, one individual of Mesocoelium monas (Trematoda: Mesocoeliidae) in the small intestine and one encysted larvae of Physalopteridae (Nematoda: Physalopteridae) attached at stomach wall. The lizard species showed a low prevalence and low richness of helminths. Moreover, H. agrius presented a low intensity of infection. The foraging mode, arboreal habit and a restricted composition of diet could favoring the low prevalence, low infection rates and low richness of helminths found in these geckonid host species.

O problema biobjetivo da árvore geradora quadrática em adjacência de arestas

The Quadratic Minimum Spanning Tree Problem (QMST) is a version of the Minimum Spanning Tree Problem in which, besides the traditional linear costs, there is a quadratic structure of costs. This quadratic structure models interaction effects between pairs of edges. Linear and quadratic costs are added up to constitute the total cost of the spanning tree, which must be minimized. When these interactions are restricted to adjacent edges, the problem is named Adjacent Only Quadratic Minimum Spanning Tree (AQMST). AQMST and QMST are NP-hard problems that model several problems of transport and distribution networks design. In general, AQMST arises as a more suitable model for real problems. Although, in literature, linear and quadratic costs are added, in real applications, they may be conflicting. In this case, it may be interesting to consider these costs separately. In this sense, Multiobjective Optimization provides a more realistic model for QMST and AQMST. A review of the state-of-the-art, so far, was not able to find papers regarding these problems under a biobjective point of view. Thus, the objective of this Thesis is the development of exact and heuristic algorithms for the Biobjective Adjacent Only Quadratic Spanning Tree Problem (bi-AQST). In order to do so, as theoretical foundation, other NP-hard problems directly related to bi-AQST are discussed: the QMST and AQMST problems. Bracktracking and branch-and-bound exact algorithms are proposed to the target problem of this investigation. The heuristic algorithms developed are: Pareto Local Search, Tabu Search with ejection chain, Transgenetic Algorithm, NSGA-II and a hybridization of the two last-mentioned proposals called NSTA. The proposed algorithms are compared to each other through performance analysis regarding computational experiments with instances adapted from the QMST literature. With regard to exact algorithms, the analysis considers, in particular, the execution time. In case of the heuristic algorithms, besides execution time, the quality of the generated approximation sets is evaluated. Quality indicators are used to assess such information. Appropriate statistical tools are used to measure the performance of exact and heuristic algorithms. Considering the set of instances adopted as well as the criteria of execution time and quality of the generated approximation set, the experiments showed that the Tabu Search with ejection chain approach obtained the best results and the transgenetic algorithm ranked second. The PLS algorithm obtained good quality solutions, but at a very high computational time compared to the other (meta)heuristics, getting the third place. NSTA and NSGA-II algorithms got the last positions

PUPSI :uma proposta de processo unificado para políticas de segurança da informação

The way to deal with information assets means nowadays the main factor not only for the success but also for keeping the companies in the global world. The number of information security incidents has grown for the last years. The establishment of information security policies that search to keep the security requirements of assets in the desired degrees is the major priority for the companies. This dissertation suggests a unified process for elaboration, maintenance and development of information security policies, the Processo Unificado para Políticas de Segurança da Informação - PUPSI. The elaboration of this proposal started with the construction of a structure of knowledge based on documents and official rules, published in the last two decades, about security policies and information security. It's a model based on the examined documents which defines the needed security policies to be established in the organization, its work flow and identifies the sequence of hierarchy among them. It's also made a model of the entities participating in the process. Being the problem treated by the model so complex, which involves all security policies that the company must have. PUPSI has an interative and developing approach. This approach was obtained from the instantiation of the RUP - Rational Unified Process model. RUP is a platform for software development object oriented, of Rational Software (IBM group). Which uses the best practice known by the market. PUPSI got from RUP a structure of process that offers functionality, diffusion capacity and comprehension, performance and agility for the process adjustment, offering yet capacity of adjustment to technological and structural charges of the market and the company

Lazer e urbanização: a dinâmica do setor de serviços no litoral de Parnamirim e Nísia Floresta - RN

The research here undertaken analyzes the process of urbanization on the coast of Panamirim - RN and Nísia Floresta - RN, arising from leisure, the main leisure expression was considered the second residence and coastal tourism. The leisure promoted the growth of businesses and public and private services to meet consumer demand in that area, which initially occurred with users of second home, and which also gradually begin to occupy the coastline of these municipalities in 1980 and more recently with the development of tourism in the 1990s until now. To undertake such an analysis, we did the georeferencing about the trade and also public and private services of that coast, characterizing them; evaluated the extent to which services deployed in this area meets the demands of tourists and users of second residence; it was also identified how the centrality of Natal interferes in the expansion of services in these locations. The spatial area of research includes the coastal municipalities of Parnamirim and Nísia Floresta, considering the limits of the census of the Instituto Brasileiro de Geografia e Estatística- IBGE, and about the time frame, it was considered the 1990s to the present day. The methodology consists of: 1. survey and reading of the literature related to the researched topic, serving as the theoretical analysis in the construction of the object studied; 2. collection and organization of secondary data by the IBGE and tourism sectors of the State of Rio Grande do Norte, Natal and main municipalities of the research; 3. Questionnaires and / or interviews with the traders, service providers, tourists, users of second homes, local residents, and government. The analysis of such data collected allowed the preparation of graphs, maps and tables that illustrate the results obtained in the research field, basing so the study. The relevance of the study is shown by the extensive survey data involving agents of the research, including tourists, users of second homes and, above all, the data for the service sector that did not exist in the analyzed area. The study results identified in the area analyzed the emergence of three new centers, arising from the urbanization process from leisure, one of them located in the municipality of Nísia Foresta Beach in Barra de Tabatinga, and two in Parnamirim, more specifically in locality Pium and Beach Pirangi do Norte. It was further observed that, being located in tourist areas, the main feature of these new centers is seasonality

Redução da mortalidade após implementação de condutas consensuais em pacientes com infarto agudo do miocárdio

OBJETIVO: Comparar a mortalidade em 30 dias com a utilização de determinados grupos de medicamentos por pacientes, entre 1992-1997, quando não se dispunham de condutas consensuais para tratamento do infarto agudo do miocárdio, e de 2000-2002, após a padronização dessas condutas em nosso serviço. MÉTODOS: Avaliados, retrospectivamente, no 1º e 2º períodos, 172 e 143 pacientes respectivamente, admitidos com diagnóstico de infarto agudo do miocárdio: foram realizados os testes estatísticos: c² para comparar proporções, teste t de Student e o de Mann-Whitney para comparação de médias ou medianas. RESULTADOS: A análise não mostrou diferença em relação aos homens, brancos e a idade média de 61 anos, nos dois períodos. Com relação aos fatores de risco clássicos, foi observada diferença apenas na incidência de dislipidemia (17 e 29%) e, quanto à estratégia terapêutica, aumento significativo do uso de: trombolíticos (39 e 61,5%), ácido acetilsalicílico (70,9 e 96,5%), betabloqueadores (34,8 e 67,8%), inibidor da enzima conversora da angiotensina (45,9 e 74,8%), nitratos (61 e 85,3%) e a redução significativa de bloqueadores de cálcio (16,8 e 5,3%), antiarrítmicos (29,1 e 9,7%) e diuréticos (50,6 e 26,6%). O uso de inotrópicos não diferiu entre os períodos (29,6 e 32,1%). A mortalidade em 30 dias apresentou redução estatisticamente significante de 22,7 para 10,5%. CONCLUSÃO: A implementação das condutas consensuais para o tratamento do infarto agudo do miocárdio foi acompanhada por significante redução da taxa de mortalidade em 30 dias.

Antigenotoxicity and antimutagenicity of lycopene in HepG2 cell line evaluated by the comet assay and micronucleus test

Epidemiological studies have provided evidence that high consumption of tomatoes effectively reduces the risk of reactive oxygen species (ROS)-mediated diseases such as cancer. Tomatoes are rich sources of lycopene, a potent singlet oxygen-quenching carotenoid. In addition to its antioxidant properties, lycopene shows an array of biological effects including antimutagenic and anticarcinogenic activities. In the present study, the chemopreventive action of lycopene was examined on DNA damage and clastogenic or aneugenic effects of H2O2 and n-nitrosodiethylamine (DEN) in the metabolically competent human hepatoma cell line (HepG2 cells). Lycopene at concentrations of 10. 25, and 50 mu M, was tested under three protocols: before, simultaneously, and after treatment with the mutagen, using the comet and micronucleus assays. Lycopene significantly reduced the genotoxicity and mutagenicity of H2O2 in all of the conditions tested. For DEN, significant reductions of primary DNA damage (comet assay) were detected when the carotenoid (all of the doses) was added in the cell culture medium before or simultaneously with the mutagen. In the micronucleus test, the protective effect of lycopene was observed only when added prior to DEN treatment. In conclusion, our results suggest that lycopene is a suitable agent for preventing chemically-induced DNA and chromosome damage. (C) 2007 Elsevier Ltd. All rights reserved.