950 resultados para Traffic engineering computing


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Background: Urban air pollutants are associated with cardiovascular events. Traffic controllers are at high risk for pollution exposure during outdoor work shifts. Objective: The purpose of this study was to evaluate the relationship between air pollution and systemic blood pressure in traffic controllers during their work shifts. Methods: This cross-sectional study enrolled 19 male traffic controllers from Santo Andre city (Sao Paulo, Brazil) who were 30-60 years old and exposed to ambient air during outdoor work shifts. Systolic and diastolic blood pressure readings were measured every 15 min by an Ambulatory Arterial Blood Pressure Monitoring device. Hourly measurements (lags of 0-5 h) and the moving averages (2-5 h) of particulate matter (PM(10)), ozone (O(3)) ambient concentrations and the acquired daily minimum temperature and humidity means from the Sao Paulo State Environmental Agency were correlated with both systolic and diastolic blood pressures. Statistical methods included descriptive analysis and linear mixed effect models adjusted for temperature, humidity, work periods and time of day. Results: Interquartile increases of PM(10) (33 mu g/m(3)) and O(3) (49 mu g/m(3)) levels were associated with increases in all arterial pressure parameters, ranging from 1.06 to 2.53 mmHg. PM(10) concentration was associated with early effects (lag 0), mainly on systolic blood pressure. However, O(3) was weakly associated most consistently with diastolic blood pressure and with late cumulative effects. Conclusions: Santo Andre traffic controllers presented higher blood pressure readings while working their outdoor shifts during periods of exposure to ambient pollutant fluctuations. However, PM(10) and O(3) induced cardiovascular effects demonstrated different time courses and end-point behaviors and probably acted through different mechanisms. (C) 2011 Elsevier Inc. All rights reserved.

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A straightforward method is proposed for computing the magnetic field produced by a circular coil that contains a large number of turns wound onto a solenoid of rectangular cross section. The coil is thus approximated by a circular ring containing a continuous constant current density, which is very close to the real situation when sire of rectangular cross section is used. All that is required is to evaluate two functions, which are defined as integrals of periodic quantities; this is done accurately and efficiently using trapezoidal-rule quadrature. The solution can be obtained so rapidly that this procedure is ideally suited for use in stochastic optimization, An example is given, in which this approach is combined with a simulated annealing routine to optimize shielded profile coils for NMR.

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Aims: The aims of the present study were to characterize fatal traffic accident victims in a major urban center in Brazil and their association with alcohol consumption. Methods: Cross-sectional study of 907 fatal traffic accident victims in Sao Paulo, in 2005. Results: Adult males between the ages of 25 and 54 represented the majority of cases with positive blood alcohol concentrations (BAC). Overall, males had a higher proportional BAC and mean BAC than females. Pedestrians, particularly those with no detectable BAC, were typically older than other victims. Most accidents (total and BAC-positive) happened on weekends between midnight and 6 a.m. Considering all victims, 39.4% were positive (BAC over 0.1 g/l). When only drivers (automobile, motorcycle and bicycle) were evaluated. 42.3% had BAC over the legal limit (0.6 g/l). Conclusions: Alcohol is associated with nearly half of all traffic accident deaths in the city of Sao Paulo. especially for days and times associated with parties and bars (weekends between 12 a.m. and 6 a.m.). (C) 2010 Elsevier Ltd. All rights reserved.

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Air pollution is an important environmental health risk factor that can result in many different gestational and reproductive negative outcomes. In this study, we have investigated the effects of two different times of exposure (before conception and during pregnancy) to urban ambient particulate matter on reproductive and pregnancy outcomes in mice. Using exposure chambers receiving filtered (F) and non-filtered (NF) air, we observed that exposed females exhibited changes in the length of estrus cycle and extended estrus and, therefore, a reduction in the number of cycles during the studied period (F2.6 +/- 0.22 and NF 1.2 +/- 0.29, p = 0.03). The mean number of antral follicles declined by 36% (p = 0.04) in NF mice (75 +/- 35.2) compared to F mice (118.6 +/- 18.4). our results further indicate a significant increase in time necessary for mating and decreased fertility and pregnancy indices (p = 0.003) in NF couples. Mean post-implantation loss rates were increased by 70% (p <= 0.005) in the NF2 group (exposed before and during pregnancy to NF air) compared to the F1 group (exposed before and during pregnancy to F air) and were influenced by both pre-gestational (p < 0.004) and gestational (p < 0.01) period exposure. Fetal weight was significantly higher in the F1 group when compared with the other groups (p < 0.001), at a 20% higher weight in the F1 group (0.86 +/- 0.18 g) than in the NF2 group (0.68 +/- 0.10g). Furthermore, fetal weight was influenced by both pre-gestational and gestational period exposure, and a significant interaction between these two factors was found (p < 0.001). This study demonstrated that exposure to ambient levels of urban traffic-generated particulate matter negatively affects different functions and stages of the reproductive process. Our results also reinforce the idea that maternal exposure to air pollution is linked to negative pregnancy outcomes, even if the exposure occurs only before conception. (C) 2009 Elsevier Inc. All rights reserved.

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The impact of particle emissions by biomass burning is increasing throughout the world. We explored the toxicity of particulate matter produced by sugar cane burning and compared these effects with equivalent mass of traffic-derived particles. For this purpose, BALB/c mice received a single intranasal instillation of either distilled water (C) or total suspended particles (15 mu g) from an urban area (SP group) or biomass burning-derived particles (Bio group). Lung mechanical parameters (total, resistive and viscoelastic pressures, static elastance, and elastic component of viscoelasticity) and histology were analyzed 24h after instillation. Trace elements and polycyclic aromatic hydrocarbons (PAHs) metabolites of the two sources of particles were determined. All mechanical parameters increased similarly in both pollution groups compared with control, except airway resistive pressure, which increased only in Bio. Both exposed groups showed significantly higher fraction area of alveolar collapse, and influx of polymorphonuclear cells in lung parenchyma than C. The composition analysis of total suspended particles showed higher concentrations of PAHs and lower concentration of metals in traffic than in biomass burning-derived particles. In conclusion, we demonstrated that a single low dose of ambient particles, produced by traffic and sugar cane burning, induced significant alterations in pulmonary mechanics and lung histology in mice. Parenchymal changes were similar after exposure to both particle sources, whereas airway mechanics was more affected by biomass-derived particles. Our results indicate that biomass particles were at least as toxic as those produced by traffic. (C) 2008 Elsevier Inc. All rights reserved.

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Objectives: The purpose of this study was to explore the clinical relevance of chronic exposure to ambient levels of traffic derived air pollution on the ocular surface. Methods: A panel study involving 55 volunteers was carried out in Sao Paulo, Brazil. We measured the mean individual levels of nitrogen dioxide (NO(2)) exposure for 7 days. All subjects answered the Ocular Symptom Disease Index (OSDI) and a symptoms inventory. Subsequently, subjects underwent Schirmer I test, biomicroscopy, vital staining and tear breakup time (TOUT) assessment. Subject`s mean daily exposure to NO(2) was categorized in quartiles. Statistical analysis was performed using one-way ANOVA, Tukey HSD and Chi-Square tests. Results: A dose-response pattern was detected between OSDI scores and NO(2) quartiles (p < 0.05). There was a significant association between NO(2) quartiles and reported ocular irritation (X(2) = 9.2, p < 0.05) and a significant negative association between TBUT and NO(2) exposure (p < 0.05, R = -0.316. Spearman`s correlation). There was a significant increase in the frequency of meibomitis in subjects exposed to higher levels of NO(2) (p < 0.05). Conclusions: Subjects exposed to higher levels of traffic derived air pollution reported more ocular discomfort symptoms and presented greater tear film instability, suggesting that the ocular discomfort symptoms and tear breakup time could be used as convenient bioindicators of the adverse health effects of traffic derived air pollution exposure. (C) 2010 Elsevier Inc. All rights reserved.

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Objective: To examine whether there is an association between fetal and/or placental weight and exposure to ambient levels of air pollution in mice. Design: Chronic experiments on mice that were exposed to polluted vs. clean air. Setting: Environmental exposure to atmospheric pollution. Animal(S): Female Swiss mice (n = 70) were maintained at different stages of gestation in an exposure chamber located at an intersection with heavy traffic in a major city in Brazil. Control mice were maintained in a similar chamber, located adjacent to the exposure chamber but equipped with filters for particles and reactive gases. Intervention(s): Animals were divided into six groups as follows: no exposure, exposure to a polluted chamber throughout gestation, exposure to a polluted chamber during the 1st week of pregnancy, exposure to a polluted chamber during the 2nd and 3rd weeks, exposure to a polluted chamber during the 1st and 2nd week, and exposure to a polluted chamber during the 3rd week. Main Outcome Measure(S): At the end of the gestational period, the determination of fetal and placental weight was performed after cesarean section. Result(s): Exposure to air pollution during the 1st week of pregnancy promoted a significant reduction in fetal weight. Mice exposed to polluted air, in any phase of gestation, presented with lower placental weight in comparison to mice maintained in clean chambers. Conclusion(s): Exposure to ambient levels of traffic pollution at early phases of gestation is a determinant for decreased final fetal weight. Placental weight is reduced with exposure to air pollution at any phase of gestation. (Fertil Steril (R) 2008;90:1921-4. (C)2008 by American Society for Reproductive Medicine.)

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Background: Traffic accidents constitute the main cause of death in the first decades of life. Traumatic brain injury is the event most responsible for the severity of these accidents. The SBN started an educational program for the prevention of traffic accidents, adapted from the American model ""Think First"" to the Brazilian environment, since 1995, with special effort devoted to the prevention of TBI by using seat belts and motorcycle helmets. The objective of the present study was to set up a traffic accident prevention program based on the adapted Think First and to evaluate its impact by comparing epidemiological variables before and after the beginning of the program. Methods: The program was executed in Maringa city, from September 2004 to August 2005, with educational actions targeting the entire population, especially teenagers and young adults. The program was implemented by building a network of information facilitators and multipliers inside the organized civil society, with widespread population dissemination. To measure the impact of the program, a specific software was developed for the storage and processing of the epidemiological variables. Results: The results showed a reduction of trauma severity due to traffic accidents after the execution of the program, mainly TBI. Conclusions: The adapted Think First was systematically implemented and its impact measured for the first time in Brazil, revealing the usefulness of the program for reducing trauma and TBI severity in traffic accidents through public education and representing a standardized model of implementation in a developing country. (C) 2009 Elsevier Inc. All rights reserved.

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Over the past years, component-based software engineering has become an established paradigm in the area of complex software intensive systems. However, many techniques for analyzing these systems for critical properties currently do not make use of the component orientation. In particular, safety analysis of component-based systems is an open field of research. In this chapter we investigate the problems arising and define a set of requirements that apply when adapting the analysis of safety properties to a component-based software engineering process. Based on these requirements some important component-oriented safety evaluation approaches are examined and compared.