985 resultados para Risk-averse optimization


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Epidemiologic studies have reported an inverse association between dairy product consumption and cardiometabolic risk factors in adults, but this relation is relatively unexplored in adolescents. We hypothesized that a higher dairy product intake is associated with lower cardiometabolic risk factor clustering in adolescents. To test this hypothesis, a cross-sectional study was conducted with 494 adolescents aged 15 to 18 years from the Azorean Archipelago, Portugal. We measured fasting glucose, insulin, total cholesterol, high-density lipoprotein cholesterol, triglycerides, systolic blood pressure, body fat, and cardiorespiratory fitness. We also calculated homeostatic model assessment and total cholesterol/high-density lipoprotein cholesterol ratio. For each one of these variables, a z score was computed using age and sex. A cardiometabolic risk score (CMRS) was constructed by summing up the z scores of all individual risk factors. High risk was considered to exist when an individual had at least 1 SD from this score. Diet was evaluated using a food frequency questionnaire, and the intake of total dairy (included milk, yogurt, and cheese), milk, yogurt, and cheese was categorized as low (equal to or below the median of the total sample) or “appropriate” (above the median of the total sample).The association between dairy product intake and CMRS was evaluated using separate logistic regression, and the results were adjusted for confounders. Adolescents with high milk intake had lower CMRS, compared with those with low intake (10.6% vs 18.1%, P = .018). Adolescents with appropriate milk intake were less likely to have high CMRS than those with low milk intake (odds ratio, 0.531; 95% confidence interval, 0.302-0.931). No association was found between CMRS and total dairy, yogurt, and cheese intake. Only milk intake seems to be inversely related to CMRS in adolescents.

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2 Centre of Research, Education, Innovation and Intervention In Sport, Faculty of Sport, University of Porto, Portugal Background: Regarding children aged _10 years, only a few international studies were conducted to determine the prevalence of and risk factors for back pain. Although other studies on the older Portuguese children point to prevalence between 17% and 39%, none exists for this specific age-group. Thus, the aim of this study was conducted to establish the prevalence of and risk factors for back pain in schoolchildren aged 7–10 years. Methods: A cross-sectional survey among 637 children was conducted. A self-rating questionnaire was used to verify prevalence and duration of back pain, life habits, school absence, medical treatments or limitation of activities. For posture assessment, photographic records with a bio-photogrammetric analysis were used to obtain data about head, acromion and pelvic alignment, horizontal alignment of the scapulae, vertical alignment of the trunk and vertical body alignment. Results: Postural problems were found in 25.4% of the children, especially in the 8- and 9-year-old groups. Back pain occurs in 12.7% with the highest values among the 7- and 10-year-old children. The probability of back pain increased 7 times when the children presented a history of school absences, 4.3 times when they experienced sleeping difficulties, 4.4 times when school furniture was uncomfortable, 4.7 times if the children perceived an occurrence of parental back pain and 2.5 times when children presented incorrect posture. Conclusions: The combination of school absences, parental pain, sleeping difficulties, inappropriate school furniture and postural deviations at the sagittal and frontal planes seem to prove the multifactorial aetiology of back pain.

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Risk acceptance has been broadly discussed in relation to hazardous risk activities and/or technologies. A better understanding of risk acceptance in occupational settings is also important; however, studies on this topic are scarce. It seems important to understand the level of risk that stakeholders consider sufficiently low, how stakeholders form their opinion about risk, and why they adopt a certain attitude toward risk. Accordingly, the aim of this study is to examine risk acceptance in regard to occupational accidents in furniture industries. The safety climate analysis was conducted through the application of the Safety Climate in Wood Industries questionnaire. Judgments about risk acceptance, trust, risk perception, benefit perception, emotions, and moral values were measured. Several models were tested to explain occupational risk acceptance. The results showed that the level of risk acceptance decreased as the risk level increased. High-risk and death scenarios were assessed as unacceptable. Risk perception, emotions, and trust had an important influence on risk acceptance. Safety climate was correlated with risk acceptance and other variables that influence risk acceptance. These results are important for the risk assessment process in terms of defining risk acceptance criteria and strategies to reduce risks.

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This study aims to analyse the relationship between safety climate and the level of risk acceptance, as well as its relationship with workplace safety performance. The sample includes 14 companies and 403 workers. The safety climate assessment was performed by the application of a Safety Climate in Wood Industries questionnaire and safety performance was assessed with a checklist. Judgements about risk acceptance were measured through questionnaires together with four other variables: trust, risk perception, benefit perception and emotion. Safety climate was found to be correlated with workgroup safety performance, and it also plays an important role in workers’ risk acceptance levels. Risk acceptance tends to be lower when safety climate scores of workgroups are high, and subsequently, their safety performance is better. These findings seem to be relevant, as they provide Occupational, Safety and Health practitioners with a better understanding of workers’ risk acceptance levels and of the differences among workgroups.

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Submitted in partial fulfillment for the Requirements for the Degree of PhD in Mathematics, in the Speciality of Statistics in the Faculdade de Ciências e Tecnologia

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European Journal of Operational Research, nº 73 (1994)

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We compared the indirect immunofluorescence assay (IFA) with Western blot (Wb) as a confirmatory method to detect antibodies anti retrovirus (HIV-1 and HTLV-I/II). Positive and negative HIV-1 and HTLV-I/II serum samples from different risk populations were studied. Sensitivity, specificity, positive, negative predictive and kappa index values were assayed, to assess the IFA efficiency versus Wb. The following cell lines were used as a source of viral antigens: H9 ( HTLV-III b); MT-2 and MT-4 (persistently infected with HTLV-I) and MO-T (persistently infected with HTLV-II). Sensitivity and specificity rates for HIV-1 were 96.80% and 98.60% respectively, while predictive positive and negative values were 99.50% and 92.00% respectively. No differences were found in HIV IFA performance between the various populations studied. As for IFA HTLV system, the sensitivity and specificity values were 97.91% and 100% respectively with positive and negative predictive values of 100% and 97.92%. Moreover, the sensitivity of the IFA for HTLV-I/II proved to be higher when the samples were tested simultaneously against both antigens (HTLV-I-MT-2 and HTLV-II-MO-T). The overall IFA efficiency for HIV-1 and HTLV-I/II-MT-2 antibody detection probed to be very satisfactory with an excellent correlation with Wb (Kappa indexes 0.93 and 0.98 respectively). These results confirmed that the IFA is a sensitive and specific alternative method for the confirmatory diagnosis of HIV-1 and HTLV-I/II infection in populations at different levels of risk to acquire the infection and suggest that IFA could be included in the serologic diagnostic algorithm.

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This study was carried out in order to obtain base-line data concerning the epidemiology of American Visceral Leishmaniasis and Chagas’ Disease in an indigenous population with whom the government is starting a dwelling improvement programme. Information was collected from 242 dwellings (1,440 people), by means of house to house interviews about socio-economic and environmental factors associated with Leishmania chagasi and Trypanosoma cruzi transmission risk. A leishmanin skin test was applied to 385 people and 454 blood samples were collected on filter paper in order to detect L. chagasi antibodies by ELISA and IFAT and T. cruzi antibodies by ELISA. T. cruzi seroprevalence was 8.7% by ELISA, L. chagasi was 4.6% and 5.1% by IFAT and ELISA, respectively. ELISA sensitivity and specificity for L. chagasi antibodies were 57% and 97.5% respectively, as compared to the IFAT. Leishmanin skin test positivity was 19%. L. chagasi infection prevalence, being defined as a positive result in the three-immunodiagnostic tests, was 17.1%. Additionally, 2.7% of the population studied was positive to both L. chagasi and T. cruzi, showing a possible cross-reaction. L. chagasi and T. cruzi seropositivity increased with age, while no association with gender was observed. Age (p<0.007), number of inhabitants (p<0.05), floor material (p<0.03) and recognition of vector (p<0.01) were associated with T. cruzi infection, whilst age ( p<0.007) and dwelling improvement (p<0.02) were associated with L. chagasi infection. It is necessary to evaluate the long-term impact of the dwelling improvement programme on these parasitic infections in this community.

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The aim of this work was to assess the influence in the diagnostic value for human hydatid disease of the composition of bovine hydatid cyst fluid (BHCF) obtained from fertile (FC) and non-fertile cysts (NFC). Eight batches from FC and 5 from NFC were prepared and analysed with respect to chemical composition: total protein, host-derived protein, carbohydrate and lipid contents. No differences were observed in the first two parameters but carbohydrate and lipid contents were shown to be higher in batches from FC than in those from NFC. Bands of 38 and 116 kD in SDS-PAGE profiles were observed to be present in BHCF from FC only. Two pools were prepared from BHCF batches obtained from FC (PFC) and NFC (PNFC), respectively. Antigen recognition patterns were analysed by immunoblot. Physicochemical conditions for adsorption of antigens to the polystyrene surface (ELISA plates) were optimized. The diagnostic value of both types of BHCF as well as the diagnostic relevance of oxidation of their carbohydrate moieties with periodate were assessed by ELISA using 42 serum samples from hydatid patients, 41 from patients with other disorders, and 15 from healthy donors. Reactivity of all sera against native antigen were tested with and without free phosphorylcholine. The best diagnostic efficiency was observed using BHCF from periodate-treated PFC using glycine buffer with strong ionic strength to coat ELISA plates.

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A case-control study was conducted to identify risk factors for death from tetanus in the State of Pernambuco, Brazil. Information was obtained from medical records of 152 cases and 152 controls, admitted to the tetanus unit in the State University Hospital, in Recife, from 1990 to 1995. Variables were grouped in three different sets. Crude and adjusted odds ratios, p-values and 95% confidence intervals were estimated. Variables selected in the multivariate analysis in each set were controlled for the effect of those selected in the others. All factors related to the disease progression - incubation period, time elapsed between the occurrence of the first tetanus symptom and admission, and period of onset - showed a statistically significant association with death from tetanus. Similarly, signs and/or symptoms occurring on admission or in the following 24 hours (second set): reflex spasms, neck stiffness, respiratory signs/symptoms and respiratory failure requiring artificial ventilation (third set) were associated with death from tetanus even when adjusted for the effect of the others.

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The objective of this study was to evaluate the prevalence and risk factors associated with HCV infection in a group of HIV seropositive patients. We analyzed the medical records of 1,457 patients. All patients were tested for HCV infection by third generation ELISA. Whenever possible, a sample of the positive patients was also tested for HCV by PCR. HCV positive patients were analyzed according to their risk factors for both infections. The prevalence of anti-HCV positive patients was 17.7% (258 patients). Eighty-two (82) of these patients were also tested by PCR and 81 were positive for HCV virus (98%). One hundred fifty-one (58.5%) were intravenous drug users (IDU); 42 (16.3%) were sexual partners of HIV patients; 23 (8.9%) were homosexual males; 12 (4.7%) had received blood transfusion; 61 (17.5%) had promiscuous sexual habits; 14 (5.4%) denied any risk factor; 12 (4.7%) were sexual partners of IDU. Two hundred four patients mentioned only one risk factor. Among them, 28 (10.9%) were sexual partners of HIV-positive patients. Although intravenous drug use was the most important risk factor for co-infection, sexual transmission seemed to contribute to the high HCV seroprevalence in this group of patients.

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In developed countries, civil infrastructures are one of the most significant investments of governments, corporations, and individuals. Among these, transportation infrastructures, including highways, bridges, airports, and ports, are of huge importance, both economical and social. Most developed countries have built a fairly complete network of highways to fit their needs. As a result, the required investment in building new highways has diminished during the last decade, and should be further reduced in the following years. On the other hand, significant structural deteriorations have been detected in transportation networks, and a huge investment is necessary to keep these infrastructures safe and serviceable. Due to the significant importance of bridges in the serviceability of highway networks, maintenance of these structures plays a major role. In this paper, recent progress in probabilistic maintenance and optimization strategies for deteriorating civil infrastructures with emphasis on bridges is summarized. A novel model including interaction between structural safety analysis,through the safety index, and visual inspections and non destructive tests, through the condition index, is presented. Single objective optimization techniques leading to maintenance strategies associated with minimum expected cumulative cost and acceptable levels of condition and safety are presented. Furthermore, multi-objective optimization is used to simultaneously consider several performance indicators such as safety, condition, and cumulative cost. Realistic examples of the application of some of these techniques and strategies are also presented.

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It is well recognized that professional musicians are at risk of hearing damage due to the exposure to high sound pressure levels during music playing. However, it is important to recognize that the musicians’ exposure may start early in the course of their training as students in the classroom and at home. Studies regarding sound exposure of music students and their hearing disorders are scarce and do not take into account important influencing variables. Therefore, this study aimed to describe sound level exposures of music students at different music styles, classes, and according to the instrument played. Further, this investigation attempted to analyze the perceptions of students in relation to exposure to loud music and consequent health risks, as well as to characterize preventive behaviors. The results showed that music students are exposed to high sound levels in the course of their academic activity. This exposure is potentiated by practice outside the school and other external activities. Differences were found between music style, instruments, and classes. Tinnitus, hyperacusis, diplacusis, and sound distortion were reported by the students. However, students were not entirely aware of the health risks related to exposure to high sound pressure levels. These findings reflect the importance of starting intervention in relation to noise risk reduction at an early stage, when musicians are commencing their activity as students.