969 resultados para FREQUENCY APPROACH


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Considering the impact of cysticercosis on public health, especially the neurologic form of the disease, neurocysticercosis (NC), we studied the frequency of positivity of anti-Taenia solium cysticercus antibodies in serum samples from 1,863 inhabitants of Cássia dos Coqueiros, SP, a municipal district located 80 km from Ribeirão Preto, an area considered endemic for cysticercosis. The 1,863 samples were tested by enzyme linked immunosorbent assay (ELISA) using an antigenic extract from Taenia crassiceps vesicular fluid (Tcra). The reactive and inconclusive ELISA samples were tested by immunoblotting. Of the 459 samples submitted to immunoblotting, 40 were strongly immunoreactive to the immunodominant 18 and 14 kD peptides. Considering the use of immunoblotting as confirmatory due to its high specificity, the anti-cysticercus serum prevalence in this population was 2.1%.

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The most preferred containers by Aedes aegypti were studied April and July (rainy and dry periods) in two Manaus neighbourhoods. In all, 2,700 premises and 13,912 containers were examined, most (87%) recorded outdoors. Out of the 13,100 inspected premises, only 1.6% showed to be positive for Aedes aegypti, summing up to 7,916 collected samples. Most frequently found containers outdoors in either neighbourhood regardless of rain or dry period were Bottles flasks and Storage, and indoors, Fixed, Flowerpots, and buckets. Productivity was estimated according to the number of premises and positive containers investigated, showing the actual container groups productivity. Considering both rainy and dry periods outdoors at Praça 14 the groups of Tyre, Flask, Bottle, Construction Equipment and Fixed, had the highest averages respectively. Construction Equipment and Flask groups were the most productive in Coroado in April. Flask, Construction Equipment and Storage groups stood out in July.

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Heterogeneous multicore platforms are becoming an interesting alternative for embedded computing systems with limited power supply as they can execute specific tasks in an efficient manner. Nonetheless, one of the main challenges of such platforms consists of optimising the energy consumption in the presence of temporal constraints. This paper addresses the problem of task-to-core allocation onto heterogeneous multicore platforms such that the overall energy consumption of the system is minimised. To this end, we propose a two-phase approach that considers both dynamic and leakage energy consumption: (i) the first phase allocates tasks to the cores such that the dynamic energy consumption is reduced; (ii) the second phase refines the allocation performed in the first phase in order to achieve better sleep states by trading off the dynamic energy consumption with the reduction in leakage energy consumption. This hybrid approach considers core frequency set-points, tasks energy consumption and sleep states of the cores to reduce the energy consumption of the system. Major value has been placed on a realistic power model which increases the practical relevance of the proposed approach. Finally, extensive simulations have been carried out to demonstrate the effectiveness of the proposed algorithm. In the best-case, savings up to 18% of energy are reached over the first fit algorithm, which has shown, in previous works, to perform better than other bin-packing heuristics for the target heterogeneous multicore platform.

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IEEE 802.11 is one of the most well-established and widely used standard for wireless LAN. Its Medium Access control (MAC) layer assumes that the devices adhere to the standard’s rules and timers to assure fair access and sharing of the medium. However, wireless cards driver flexibility and configurability make it possible for selfish misbehaving nodes to take advantages over the other well-behaving nodes. The existence of selfish nodes degrades the QoS for the other devices in the network and may increase their energy consumption. In this paper we propose a green solution for selfish misbehavior detection in IEEE 802.11-based wireless networks. The proposed scheme works in two phases: Global phase which detects whether the network contains selfish nodes or not, and Local phase which identifies which node or nodes within the network are selfish. Usually, the network must be frequently examined for selfish nodes during its operation since any node may act selfishly. Our solution is green in the sense that it saves the network resources as it avoids wasting the nodes energy by examining all the individual nodes of being selfish when it is not necessary. The proposed detection algorithm is evaluated using extensive OPNET simulations. The results show that the Global network metric clearly indicates the existence of a selfish node while the Local nodes metric successfully identified the selfish node(s). We also provide mathematical analysis for the selfish misbehaving and derived formulas for the successful channel access probability.

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A novel surface molecularly-imprinted (MI) material to detect myoglobin (Myo) using gold screen printed electrodes (SPE) was developed. The sensitive detection was carry out by introducing a carboxylic polyvinyl chloride (PVC-COOH) layer on gold SPE surface. Myo was attached to the surface of gold SPE/PVC-COOH and the vacant spaces around it were filled by polymerizing acrylamide and N,N-methylenebisacrylamide (cross-linker). This polymerization was initiated by ammonium persulphate. After removing the template, the obtained material was able to rebind Myo and discriminate it among other interfering species. Various characterization techniques including electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) confirmed the surface modification. This sensor seemed a promising tool for screening Myo in point-of-care.

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Dissertation presented to obtain the Ph.D degree in Biology

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While fractional calculus (FC) is as old as integer calculus, its application has been mainly restricted to mathematics. However, many real systems are better described using FC equations than with integer models. FC is a suitable tool for describing systems characterised by their fractal nature, long-term memory and chaotic behaviour. It is a promising methodology for failure analysis and modelling, since the behaviour of a failing system depends on factors that increase the model’s complexity. This paper explores the proficiency of FC in modelling complex behaviour by tuning only a few parameters. This work proposes a novel two-step strategy for diagnosis, first modelling common failure conditions and, second, by comparing these models with real machine signals and using the difference to feed a computational classifier. Our proposal is validated using an electrical motor coupled with a mechanical gear reducer.

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Parasitic infections caused by intestinal protozoan and helminths affect more than two billion people worldwide and chemotherapy is the most commonly used therapeutic procedure. Considering the problems created by parasitic infections and the incorrect use of drugs, the aim of this work was to detect the frequency of enteroparasites infection and to estimate the use of chemotherapeutic agents in children living in the periphery of the city of Porto Alegre, RS, Brazil. Ninety-six preschool age children, who had parasitological exams and who used antiparasitic drugs, were analyzed. The efficacy of treatment was evaluated by stool examination repeated six months after treatment. The same diagnostic test was used to evaluate parasitological cure, which was defined as absence of eggs and cysts in the stool. From these children, 79 (82.3%) were contaminated by some species of parasite, the most prevalent were Ascaris lumbricoides, Trichuris trichiura and Giardia lamblia. The most commonly used drugs were mebendazole (86% of prescriptions) and metronidazole (30.3%). The cure rate in the 79 children, examined 6 months after treatment, was 65.3% for A. lumbricoides and 66.1% for T. trichiura. This study suggests that a continuous education program regarding the prevention and treatment of parasitic infections is an essential tool for their eradication.

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In a transversal study on a sample of 386 children and adolescents from an outpatient clinic for filariasis in Recife, Northeast Brazil, the frequency of anti-Toxocara antibodies and its relation to age, gender, number of peripheral eosinophils, Wuchereria bancrofti microfilariae and intestinal helminths was determined. The total anti-Toxocara IgG antibody frequency was 39.4%, by ELISA technique. The difference in frequency between males (40.1%) and females (37.6%) was not statistically significant. The 6 to 10-year-old subset presented the highest frequency of anti-Toxocara antibodies (60%), and within this age group there was a statistically significant male bias. There was also a significant association between the number of eosinophils and the presence of anti-Toxocara antibodies. Intestinal parasite frequency was 52.1%, but no association was found between this data and the presence of anti-Toxocara antibodies. In the present sample, 42.2% of the patients were Wuchereria bancrofti carriers, however, again this was not associated with the presence of anti-Toxocara antibodies. In conclusion, anti-Toxocara antibodies were highly prevalent in this sample. The present data show that there is no cross correlation between anti-Toxocara IgG antibody and the presence of intestinal helminths and filariasis.

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Toxocara species are most common roundworms of Canidae and Felidae. Human toxocariasis develops by ingesting of embryonated eggs in contaminated soil. There is no previous report of Toxocara contamination in the soil samples from the public areas in Bangkok. For this reason our study have been carried out to examine the frequency of Toxocara eggs in public yards in Bangkok, Thailand. A total of 175 sand and clay samples were collected and examined for parasite eggs. According to this study, Toxocara eggs were detected from 10 (5.71%) of 175 soil samples. The high rate of contamination in this study implies the importance of the control of this possible zoonotic disease: control of abandon of dogs and cats, is still necessary.

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Salmonella spp. are the etiologic agents of salmonellosis, a worldwide spread zoonoses causing foodborne outbreaks and clinical diseases. By serological identification, Salmonella enterica subsp. enterica serotype 1,4,[5],12:i:- accounted for 8.8% of human and 1.6% of nonhuman Salmonella strains isolated in São Paulo State, during 1991-2000. A total of 28.6% of them amplified a fragment corresponding to H:1,2 (flagellar phase two) through PCR analysis and were further assigned as S. Typhimurium. Antimicrobial resistance was detected in 36.3% of the 369 PCR-negative strains tested, including the multiresistance to ampicillin, chloramphenicol, sulfonamides, tetracycline, and streptomycin.

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Diversity of mosquito species was evaluated in different habitats before and after the Igarapava reservoir flooding in the Grande River, Southern Cerrado of Brazil. We aimed at verifying changes in these mosquito populations in consequence of the lake formation. Four habitats were selected as sampling stations: peridomiciliary habitat, pasture, "veredas" and gallery forest patch. Bimonthly collections were made with the Shannon trap and human bait, including diurnal, crepuscular and nocturnal period of mosquito activity. The Shannon Index results from the potential vectors were compared using Student t-test. Aedes scapularis, Anopheles darlingi and An. albitarsis senso latu seasonal abundance were described with moving average and compared using chi2 test. There were changes in the mosquito frequency in the habitats, except for the "veredas" that was 13 km away from the catchment area. The altering in mosquito species seasonal abundance suggests breeding places expansion. Diversity indexes can be used to monitor changes in mosquito vector population in environments where abrupt disturbance can alter disease transmission cycles.

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Poster presented in 12th European Conference on Wireless Sensor Network (EWSN 2015). 9 to 11, Feb, 2015. Porto, Portugal.

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RESUMO: O aborto recorrente (AR) é um evento extremamente traumático com grande impacto na vida dos casais. Apesar de avanços significativos verificados na investigação médica, cerca de 50% dos casos continua sem uma causa identificada. Alguns aspectos como a caracterização inadequada das doentes e das perdas gestacionais, assim como diferentes metodologias utilizadas no seu estudo, têm influenciado a prevalência de alguns dos factores causais e dificultado a compreensão do AR. Da mesma forma, pouco se sabe sobre as diferenças de género na vivência psicológica do aborto recorrente e das suas eventuais repercussões para o relacionamento do casal, centrando-se os poucos estudos existentes preferencialmente na mulher. Por esta razão, o objectivo desta tese foi a caracterização dos factores médicos associados ao AR e das consequências psicológicas desta entidade, contribuindo para promover estratégias clínicas baseadas na evidência específica. Na primeira parte desta tese (capítulos 1 e 2), após uma breve introdução geral e através de uma revisão da literatura, efectua-se uma reflexão sobre o tema, abordando a epidemiologia do aborto recorrente, os factores médicos e os aspectos psicológicos associados. Nos capítulos 3 e 4 descrevemos três estudos efectuados em mulheres portuguesas com aborto recorrente. O primeiro estudo teve por objectivo caracterizar os factores médicos e determinar o padrão da perda recorrente de gravidez, numa coorte de mulheres submetidas a um protocolo de diagnóstico definido. As participantes foram agrupadas de acordo com a paridade (AR primário ou secundário) e a idade gestacional das perdas (embrionárias ou fetais). As anomalias da cavidade uterina, a SAAF e as translocações equilibradas parentais foram os factores mais prevalentes. 15,6% das participantes eram obesas. Em 55,5% dos casos não foi identificado nenhum factor. A história obstétrica materna influenciou significativamente os resultados encontrados: os factores anatómicos e a SAAF foram mais prevalentes em nulíparas e as perdas inexplicadas foram mais frequentes em mulheres com AR secundário. Assim, os nossos dados reforçam os resultados de pesquisas anteriores sobre a importância da obesidade, da síndrome de anticorpos antifosfolípidos e das anomalias uterinas estruturais como factores associados ao AR e mostram que os a paridade é um moderador da importância desses factores. Capítulo 6 94 A ausência de resultados consensuais na literatura sobre a etiologia do AR condiciona a pesquisa sistemática de alguns factores, envolvendo exames dispendiosos, muitas vezes sem que exista evidência que suporte a sua associação com esta entidade. A trombofilia hereditária é uma das condições frequentemente investigadas nestas doentes. O nosso segundo estudo pretende contribuir para clarificar o papel de duas mutações (factor V Leiden e protrombina G20210A) na perda recorrente de gravidez e esclarecer a necessidade do seu rastreio nestas situações. Foi efectuada a pesquisa destes polimorfismos em 100 mulheres com AR inexplicado e num grupo de controlo de multíparas sem história de perdas de gravidez. Na nossa amostra não se verificou uma associação entre perdas embrionárias recorrentes e estas mutações. Nas mulheres com este tipo de perdas, a prevalência do FLV foi inclusive menor do que a verificada nos controlos. Pelo contrário, nas participantes com perdas fetais a prevalência destes polimorfismos foi muito superior à verificada nos controlos, sugerindo uma possível associação entre estas duas entidades. A pequena dimensão deste último subgrupo de mulheres, não nos permitiu contudo tirar conclusões. Uma investigação prospectiva multicêntrica é necessária antes de recomendar a pesquisa da trombofilia hereditária na investigação do AR. Procurámos incluir também nesta tese uma dimensão psicológica e contribuir assim para o conhecimento dos processos relacionais originados pelo AR. No terceiro estudo foram investigadas as diferenças de género na vivência do AR e o seu impacto no relacionamento e sexualidade do casal. Participaram neste estudo 30 casais sem filhos, com pelo menos 3 abortos espontâneos consecutivos. Cada membro do casal respondeu a um conjunto de questionários (Impact of Events Scale, Perinatal Grief Scale, Partnership Questionnaire e Intimate Relationship Scale). Os resultados mostram que as mulheres sofrem mais intensamente do que os homens com o AR, relacionando-se a intensidade do seu sofrimento com a qualidade do relacionamento conjugal. A sexualidade do casal é também afectada pelo stress e pelo sofrimento associados ao AR. Uma avaliação e acompanhamento deste tipo de problemas são imprescindíveis para ajudar estes casais a manterem a qualidade afectiva e sexual da sua relação. Finalmente, no capítulo 5 sumariámos as conclusões de toda a contribuição pessoal para a investigação sobre os factores associados e repercussões para o casal da perda recorrente de gravidez.-------------------ABSTRACT: Recurrent miscarriage (RM), a rare condition, has been described as a traumatic event for couples. Parental chromosomal anomalies, maternal thrombophilic disorders and structural uterine anomalies have been directly associated with RM. However, despite significant advances in medical research, the vast majority of cases remain unexplained. Aspects as the ethnic diversity of the population with different expression of genes, the inappropriate characterization of patients and of pregnancy losses, as well as different methodologies used in their study, have influenced the prevalence of etiological factors and have hampered the understanding of this problem. Similarly, little is known about gender differences in psychological experience of RM and its implications for the relationship of the couple. The first objective of this thesis is the characterization of the medical factors and of the psychological consequences related with RM, in the Portuguese population, helping to promote specific evidence-based clinical strategies. In the first part of this thesis, and after a brief general introduction (Chapter 1), a critical review of literature on the definition, the epidemiology and the dimensions involved, with a special emphasis on associated medical and psychological aspects of recurrent miscarriage, is presented (Chapter 2). In Chapters 3 and 4 we describe three studies carried out in Portuguese couples with RM. The first study aimed to investigate the etiological factors and the pattern of pregnancy loss in a cohort of women with RM. Subjects were divided in groups according to their parity (primary or secondary RM) and time of pregnancy loss (embryonic or fetal). Parental chromosome anomalies, uterine anomalies and antiphospholipid syndrome were the most prevalent medical factors. 15.6% of the women were obese. In the majority of cases (55.5%) no identifiable cause was detected. Parity influenced significantly our results. There was a higher prevalence of anatomic factors and antiphospholipid syndrome in primary RM. On the other hand, unexplained losses were more frequent in secondary RM. Except for the parental chromosomal abnormalities; the frequency of risk factors was similar among women with fetal or embryonic losses. Our data emphasizes the results of previous research on the importance of obesity, antiphospholipid syndrome and structural uterine abnormalities as known risk factors for RM, and shows that parity is an important moderator of the weight of those risk factors. Our second study aims to clarify the role of two mutations (factor V Leiden and prothrombin G20210A) and elucidate the need for their screening in Portuguese women with RM. FVL and PT G20210A analysis was carried out in 100 women with three or more consecutive miscarriages and a control group of 100 parous controls with no history of pregnancy losses. Secondary analysis was made regarding gestational age at miscarriage (embryonic and fetal loss). Overall the prevalence of FVL and PT G20210A was similar in RM women compared with controls. In the RM embryonic subgroup of women, FVL prevalence was inclusively lower than that of controls. Conversely in women with fetal losses both polymorphisms were much more frequent, although statistical significance was not reached due to the small size of this subgroup of patients. These data indicate that inherited maternal thrombophilia is not associated with RM prior to 10 weeks of gestation. Therefore, its screening is not indicated as an initial approach in Portuguese women with RM and a negative personal history of thromboembolic.96 Our second study aims to clarify the role of two mutations (factor V Leiden and prothrombin G20210A) and elucidate the need for their screening in Portuguese women with RM. FVL and PT G20210A analysis was carried out in 100 women with three or more consecutive miscarriages and a control group of 100 parous controls with no history of pregnancy losses. Secondary analysis was made regarding gestational age at miscarriage (embryonic and fetal loss). Overall the prevalence of FVL and PT G20210A was similar in RM women compared with controls. In the RM embryonic subgroup of women, FVL prevalence was inclusively lower than that of controls. Conversely in women with fetal losses both polymorphisms were much more frequent, although statistical significance was not reached due to the small size of this subgroup of patients. These data indicate that inherited maternal thrombophilia is not associated with RM prior to 10 weeks of gestation. Therefore, its screening is not indicated as an initial approach in Portuguese women with RM and a negative personal history of thromboembolic. In our third study, we investigate gender differences in RM experience and its impact on the couple's relationship and sexuality. Each member of 30 couples with RM answered a set of questionnaires, including the Impact of Events Scale (Horowitz et al., 1979), the Perinatal Grief Scale (Toedter et al., 1988), the Partnership Questionnaire (Hahlweg, 1979) and the Intimate Relationship Scale (Hetherington e Soeken, 1990). Results showed that men do grieve, but less intensely than women. Although the quality of the couple‟s relationship seemed not to be adversely affected by RM, both partners described sexual changes after those events. Grief was related to the quality of communication in the couple for women, and to the quality of sex life for men. An understanding of such issues is critical in helping these couples to maintain sexual and affective quality of their relationship. Finally, in Chapter 5, conclusions and clinical implications of all personal contribution to the investigation on associated factors and relational consequences of recurrent miscarriage are presented.