Children's exposure to indoor air in schools: Impact on wheezing

Wheezing is a common symptom in childhood and has been associated with air pollution. Children spend a large part of their time in school, this being the most important indoor environment apart from home. However, studies on the impact of children's indoor air pollution exposure at schools on respiratory health are scarce. Thus, this study aimed to assess the impact of children's exposure to indoor air pollution in a total of five urban nursery and primary schools on active wheezing. Multivariate logistic regression models were used to estimate the associations, adjusted for sex, age group (pre-school/primary school) and parental history of asthma. A microenvironmental modelling approach was used to estimate indoor air pollution exposure to each of the pollutants exceeding legislation limit values (CO2, formaldehyde and PM2.5), as the sum of the product of time spent by the child in different indoor school microenvironments and the time-averaged concentration measured in each microenvironment. Measurements were performed in 11 classrooms, two bedrooms and two canteens in Porto, Portugal. A total of 164 completed parent-reported questionnaires derived from the International Study of Asthma and Allergies in Childhood allowed to identify active wheezing (at least one wheeze episode in the previous 12 months) in 16.5% of the studied children. Although not statistically significant, the studied children's exposure to indoor air pollution in nursery and primary schools seemed to be associated with an increase in the odds of having active wheezing especially for PM2.5 (OR = 1.57, p-value = 0.675). These results highlight the importance of applying indoor air pollution mitigation measures in nursery and primary schools. The impacts of those measures, on both indoor air quality and children's respiratory health, should be evaluated in future studies. (c) 2019 WIT Pres

Sistemas de cultivo do guaranazeiro.

O estudo foi iniciado em 1975 pela CEPLAC, INPA e Embrapa com a implantação de 12 sistemas de cultivo, visando investigar várias formas de manejo para o uso dos solos amazônicos. Dentre eles foi incluído uma parcela de 1 hectare de guaraná cuja condução passou a ser efetuada pela UEPAE de Manaus a partir de 1977

Maximizing the Conditional Expected Reward for Reaching the Goal

The paper addresses the problem of computing maximal conditional expected accumulated rewards until reaching a target state (briefly called maximal conditional expectations) in finite-state Markov decision processes where the condition is given as a reachability constraint. Conditional expectations of this type can, e.g., stand for the maximal expected termination time of probabilistic programs with non-determinism, under the condition that the program eventually terminates, or for the worst-case expected penalty to be paid, assuming that at least three deadlines are missed. The main results of the paper are (i) a polynomial-time algorithm to check the finiteness of maximal conditional expectations, (ii) PSPACE-completeness for the threshold problem in acyclic Markov decision processes where the task is to check whether the maximal conditional expectation exceeds a given threshold, (iii) a pseudo-polynomial-time algorithm for the threshold problem in the general (cyclic) case, and (iv) an exponential-time algorithm for computing the maximal conditional expectation and an optimal scheduler.Comment: 103 pages, extended version with appendices of a paper accepted at TACAS 201

Drought and the interannual variability of stem growth in an aseasonal, everwet forest

Linking drought to the timing of physiological processes governing tree growth remains one limitation in forecasting climate change effects on tropical trees. Using dendrometers, we measured fine-scale growth for 96 trees of 25 species from 2013 to 2016 in an everwet forest in Puerto Rico. Rainfall over this time span varied, including an unusual, severe El Niño drought in 2015. We assessed how growing season onset, median day, conclusion, and length varied with absolute growth rate and tree size over time. Stem growth was seasonal, beginning in February, peaking in July, and ending in November. Species growth rates varied between 0 and 8 mm/year and correlated weakly with specific leaf area, leaf phosphorus, and leaf nitrogen, and to a lesser degree with wood specific gravity and plant height. Drought and tree growth were decoupled, and drought lengthened and increased variation in growing season length. During the 2015 drought, many trees terminated growth early but did not necessarily grow less. In the year following drought, trees grew more over a shorter growing season, with many smaller trees showing a post-drought increase in growth. We attribute the increased growth of smaller trees to release from light limitation as the canopy thinned because of the drought, and less inferred hydraulic stress than larger trees during drought. Soil type accounted for interannual and interspecific differences, with the finest Zarzal clays reducing tree growth. We conclude that drought affects the phenological timing of tree growth and favors the post-drought growth of smaller, sub-canopy trees in this everwet forest

Evaluation of Low-Cost Mitigation Measures Implemented to Improve Air Quality in Nursery and Primary Schools

Indoor air pollution mitigation measures are highly important due to the associatedhealth impacts, especially on children, a risk group that spends significant time indoors. Thus,the main goal of the work here reported was the evaluation of mitigation measures implementedin nursery and primary schools to improve air quality. Continuous measurements of CO2, CO,NO2, O3, CH2O, total volatile organic compounds (VOC), PM1, PM2.5, PM10, Total SuspendedParticles (TSP) and radon, as well as temperature and relative humidity were performed in twocampaigns, before and after the implementation of low-cost mitigation measures. Evaluation of thosemitigation measures was performed through the comparison of the concentrations measured in bothcampaigns. Exceedances to the values set by the national legislation and World Health Organization(WHO) were found for PM2.5, PM10, CO2 and CH2O during both indoor air quality campaigns.Temperature and relative humidity values were also above the ranges recommended by AmericanSociety of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE). In general, pollutantconcentrations measured after the implementation of low-cost mitigation measures were significantlylower, mainly for CO2. However, mitigation measures were not always sufficient to decrease thepollutants' concentrations till values considered safe to protect human health

Análise de desempenho econômico da produção orgânica de leite: estudo de caso no Distrito Federal

Neste trabalho, objetivou-se analisar economicamente a produção orgânica de leite. Para esta avaliação foram utilizados os dados obtidos em uma propriedade certificada como orgânica, localizada no Distrito Federal, durante os períodos de 2002 e 2003. A Renda Líquida (RL) por litro de leite foi positiva no ano de 2002 e negativa no de 2003, considerando-se o preço do leite a R$0,40/ L, (preço histórico pago ao produtor de leite convencional na região), apresentando resultados positivos com o preço simulado de R$ 0,80/L (preço pago aos produtores orgânicos nas Regiões Sul e Sudeste do país). Os índices de produtividade foram semelhantes aos observados nas propriedades convencionais. A produção orgânica de leite pode ser uma alternativa economicamente viável para a pecuária, desde que haja uma remuneração superior à praticada para o leite convencional

Verification and Control of Turn-Based Probabilistic Real-Time Games

Quantitative verification techniques have been developed for the formal analysis of a variety of probabilistic models, such as Markov chains, Markov decision process and their variants. They can be used to produce guarantees on quantitative aspects of system behaviour, for example safety, reliability and performance, or to help synthesise controllers that ensure such guarantees are met. We propose the model of turn-based probabilistic timed multi-player games, which incorporates probabilistic choice, real-time clocks and nondeterministic behaviour across multiple players. Building on the digital clocks approach for the simpler model of probabilistic timed automata, we show how to compute the key measures that underlie quantitative verification, namely the probability and expected cumulative price to reach a target. We illustrate this on case studies from computer security and task scheduling