582 research outputs found

    Spatial variability of throughfall water and chemistry and forest floor water content in a Douglas fir forest stand

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    International audienceThis study focuses on spatial variability of throughfall water and chemistry and forest floor water content within a Douglas fir (Pseudotsuga menziesii, Franco L.) forest plot. Spatial patterns of water and chemistry (NH4+, NO3?, SO42-, Cl?, Mg2+, Ca2+, Na+ and K+) were compared and tested for stability over time. The spatial coefficient of variation (CV) was between 18 and 26% for amounts of throughfall water and ions, and 17% for forest floor water content. Concentrations and amounts of all ions were correlated significantly. Ion concentrations were negatively correlated with throughfall water amounts, but, except for NH4+, there was no such relation between throughfall water and ion amounts. Spatial patterns of throughfall water fluxes and forest floor water contents were consistent over time; patterns of ion fluxes were somewhat less stable. Because of the spatial variability of forest floor thickness and drainage, it was not possible to relate patterns in throughfall water directly to patterns in water content. The spatial variability of throughfall nitrogen and forest floor water contents can cause significant variability in NO3? production within the plot studied. Keywords: nutrient throughfall, forest floor water, spatial variability, time-stability, nitrogen</p

    Towards reduced uncertainty in catchment nitrogen modelling: quantifying the effect of field observation uncertainty on model calibration

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    International audienceThe value of nitrogen (N) field measurements for the calibration of parameters of the INCA nitrogen in catchment model is explored and quantified. A virtual catchment was designed by running INCA with a known set of parameters, and field "measurements" were selected from the model run output. Then, using these measurements and the Shuffled Complex Evolution Metropolis algorithm (SCEM-UA), four of the INCA model parameters describing N transformations in the soil were optimised, while the measurement uncertainty was increased in subsequent steps. Considering measurement uncertainty typical for N field studies, none of the synthesised datasets contained sufficient information to identify the model parameters with a reasonable degree of confidence. Parameter equifinality occurred, leading to considerable uncertainty in model parameter values and in modelled N concentrations and fluxes. Fortunately, combining the datasets in a multi-objective calibration was found to be effective in dealing with these equifinality problems. With the right choice of calibration measurements, multi-objective calibrations resulted in lower parameter uncertainty. The methodology applied in this study, using a virtual catchment free of model errors, is proposed as a useful tool foregoing the application of a N model or the design of a N monitoring program. For an already gauged catchment, a virtual study can provide a point of reference for the minimum uncertainty associated with a model application. When setting up a monitoring program, it can help to decide what and when to measure. Numerical experiments indicate that for a forested, N-saturated catchment, a fortnightly sampling of NO3 and NH4 concentrations in stream water may be the most cost-effective monitoring strategy. Keywords: INCA, nitrogen model, parameter uncertainty, multi-objective calibration, virtual catchment, experimental desig

    Psychological outcome and quality of life in children born with congenital diaphragmatic hernia

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    OBJECTIVE: To assess psychological and social functioning as well as health-related quality of life and its early determinants in children born with congenital diaphragmatic hernia (CDH). DESIGN: Cross-sectional follow-up study. SETTING: Outpatient clinic of a tertiary care hospital. PARTICIPANTS: Thirty-three CDH survivors aged 6-16 years. Main exposure: Patients who developed CDH associated respiratory distress within 24 hours after birth. MAIN OUTCOME MEASURE: Psychological and social functioning assessed with the Wechsler intelligence scale for children (WISC-R), Bourdon-Vos test, Beery Developmental Test of visual motor integration, Child Behaviour Checklist (CBCL) and Teacher Report Form (TRF). Health-related quality of life assessed with the Child Health Questionnaire (CHQ) and the Health Utilities Index (HUI). RESULTS: Normal mean total IQ (100.0 +/- 13.2) and normal visual-motor integration, but significantly lower results for sustained attention (Bourdon-Vos test (38.8 +/- 11.2 points)) were found. Learning difficulties were reported by 30% of the parents. Eight children had scores in the clinical range on the CBCL and/or TRF, indicating clinical significant behavioural problems. Except for the CHQ scale "General health", health status was not different from the reference population. No significant correlations between test results and severity of CDH were found, except an association of general health and physical functioning with length of hospital stay. CONCLUSION: CDH patients are at risk for relevant subtle cognitive and behavioural problems, probably not related to CDH severity. These may contribute to school failure and need for special educational services. Perception of general health is reduced when compared to the reference population indicating that CDH survivors and their parents believe their health is poor and likely to get wors

    Do children report differently from their parents and from observed data? Cross-sectional data on fruit, water, sugar-sweetened beverages and break-time foods

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    textabstractBackground: Reliable assessment of children's dietary behaviour is needed for research purposes. The aim of this study was (1) to investigate the level of agreement between observed and child-reported break-time food items; and (2) to investigate the level of agreement between children's reports and those of their parents regarding children's overall consumption of fruit, water and sugar-sweetened beverages (SSB). Methods: The children in this study were 9-13 years old, attending primary schools in Rotterdam, the Netherlands. Children were observed with respect to foods brought for break-time at school. At the same day, children completed a questionnaire in which they were asked to recall the food(s) they brought to school to consume during break-time. Only paired data (observed and child-reported) were included in the analyses (n = 407 pairs). To determine each child's daily consumption and average amounts of fruit, water and SSB consumed, children and their parents completed parallel questionnaires. Only paired data (parent-reported and child-reported) were included in the analyses (n =275 pairs). The main statistical measures were level of agreement between break-time foods, fruit, water and SSB; and Intra-class Correlation Coefficients (ICC). Results: More children reported bringing sandwiches and snacks for break-time than was observed (73 % vs 51 % observed and 84 % vs 33 % observed). The overall agreement between observed and child-reported break-time foods was poor to fair, with ICC range 0.16-0.39 (p < 0.05). Children reported higher average amounts of SSB consumed than did their parents (1.3 vs 0.9 L SSB, p < 0.001). Child and parent estimations of the child's water and fruit consumption were similar. ICC between parent and child reports was poor to good (range 0.22-0.62, p < 0.05). Conclusion: Children report higher on amount of break-time foods as compared to observations and children's reports of SSB consumption are higher than those of their parents. Since the level of agreement between the observed breaktime foods and that reported by children and the agreement of child's intake between parent and child reports are relatively weak, future studies should focus on improving methods of evaluating children's consumption behaviour or on ways on how to best use and interpret multiple-source dietary intake data

    Health-related problems and quality of life in patients with syndromic and complex craniosynostosis

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    Purpose: We conducted this study to gauge the health-related problems, quality of life and the performance of the Health Utility Index Mark 3 (HUI-3) in patients with syndromic and complex craniosynostosis. Patients with syndromic and complex craniosynostosis have various physical and mental problems. More insight on these problems, per syndrome, could provide guidance to improve patient treatment and follow-up. Methods: A cross-sectional, comparative study on 131 patients and their parents was performed. Health-related quality of life was measured with the HUI-3 and the Visual Analogue Scale (VAS). All data were compared to a normative Dutch population. Vision, hearing and intelligence were objectively measured. Results: The HUI-3 and the VAS were significant lower compared to the normative Dutch population. All syndromes have a high prevalence of vision and speech problems. Cognitive problems were mainly reported in patients with Apert, Crouzon and Muenke syndrome. Ambulation and dexterity problems were seen in Apert, Crouzon, Saethre-Chotzen and complex craniosynostosis. Only patients with Apert syndrome scored significantly worse on pain. The HUI-3 had a medium to strong correlation with the objectively measured outcomes. Conclusions: The overall quality of life is lower in patients with syndromic and complex craniosynostosis. To improve quality of life, more attention is needed for problems with vision and speech

    Depressive symptoms and clustering of risk behaviours among adolescents and young adults attending vocational education: a cross-sectional study

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    BACKGROUND: Depressive symptoms and risk behaviours often do not occur in isolation among adolescents and young adults. In order to improve intervention programmes, more research is needed to elucidate the clustering of risk behaviours, the association with depressive symptoms, and demographic variables. Therefore, this study examined the clustering of risk behaviours, the association with depressive symptoms, and demographic variables among adolescents and young adults in vocational education. Furthermore, the prevalence of depressive symptoms and risk behaviours was examined.METHODS: This study included 584 students (mean age 18.3 years) attending vocational education in the Netherlands. Depressive symptoms and risk behaviours (binge drinking, cannabis use, smoking, delinquency and incurring debts) were assessed with self-report questionnaires. Truancy was monitored via the school registration system. Principal Components Analysis (PCA) was conducted to assess the factor structure of the risk behaviours (i.e. clustering). Linear regression analyses with a bootstrapping method were performed to assess the associations.RESULTS: Binge drinking was reported by 50.5% and cannabis use by 14.2% of the students (both in the past 4 weeks), whereas 37.7% reported currently being a smoker. More than 10% reported having been questioned at a police station in the past year. Furthermore, 82.2% had been truanting in the first two months of education, 21.0% reported having debts and 29.2% reported clinically-relevant depressive symptoms. The PCA indicated two clusters. The 'substance use' cluster consisted of the risk behaviours: binge drinking, cannabis use and smoking. The 'problem behaviours' cluster consisted of the risk behaviours: delinquency, truancy and incurring debts. Both clusters were associated with depressive symptoms. Various demographic variables were associated with both clusters.CONCLUSIONS: Risk behaviours formed two clusters, both of which were associated with depressive symptoms. These findings underscore the importance of screening adolescents and young adults at lower educational levels for multiple risk behaviours and depressive symptoms and of focusing on multiple risk behaviours in interventions simultaneously

    Multidimensional energy poverty and acute respiratory infection in children under 5 years of age:evidence from 22 low-income and middle-income countries

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    Background:In low-income and middle-income countries (LMICs), energy poverty has predominantly been studied from the unidimensional perspective of indoor air pollution. Acute respiratory infection (ARI) in children under 5 years of age is the most important disease associated with indoor air pollution attributable to solid fuel use in LMICs. This study aimed to extend the existing knowledge on the association between energy poverty and ARI among children under 5 years of age in LMICs, by adopting a multidimensional perspective.Methods:Using Demographic and Health Surveys from 22 LMICs, data from 483 088 children were analysed (mean age 2.00 years (SD 1.41); 51.3% male). Energy poverty was measured using the Multidimensional Energy Poverty Index (MEPI) (range 0–1), which comprises five dimensions of essential energy services. Binary logistic regression models were conducted to study the association between MEPI and ARI, adjusting for child, maternal, household and environmental characteristics.Results:A 0.1 increase in MEPI score was associated with greater odds of ARI (aOR 1.05; 95% CI 1.04 to 1.07). Likewise, MEPI indicators using biomass for cooking (aOR 1.15; 95% CI 1.07 to 1.23) and lack of access to electricity (aOR 1.17; 95% CI 1.10 to 1.26), entertainment/education appliances (aOR 1.07; 95% CI 1.02 to 1.13) and household appliances (aOR 1.12; 95% CI 1.04 to 1.21) were associated with greater odds of ARI.Conclusion:Multidimensional energy poverty was associated with greater odds of ARI in children under 5 years of age living in 22 LMICs. Hence, our findings justify the design and implementation of interventions that address energy poverty from a multidimensional perspective, integrating energy affordability and accessibility

    Why Do Parents with Toddlers Store Poisonous Products Safely?

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    Unintentional poisoning is a major cause of nonfatal injuries in children aged 0–24 months. Associations between self-reported habits on the child safe storage of medication and cleaning products and family, and psychosocial factors were assessed, using a model based on the Protection Motivation Theory. By identifying correlates of safety behavior in this manner, more insight in factors which influence this behavior is obtained. Health promotion activities in order to promote safety behavior should address these factors in order to increase the effectiveness of the health message. Data were gathered from a cross-sectional survey using self-administered questionnaires, mailed to a population sample of 2470 parents with toddlers. The results indicate that the promotion of safe storage of medication and cleaning products should address the family situation, personal cognitive factors as well as social factors. Interventions should particularly focus on parents' self-efficacy of storing poisonous products in a child safe manner and on the vulnerability of their child in their home concerning an unintentional poisoning incident

    Adolescents and MP3 Players: Too Many Risks, Too Few Precautions

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    OBJECTIVE. The goal was to assess risky and protective listening behaviors of adolescent users of MP3 players and the association of these behaviors with demographic characteristics and frequency of use. METHODS. In 2007, 1687 adolescents (12–19 years of age) in 68 classes in 15 Dutch secondary schools were invited to complete questionnaires about their music-listening behaviors. RESULTS. Ninety percent of participants reported listening to music through earphones on MP3 players; 32.8% were frequent users, 48.0% used high volume settings, and only 6.8% always or nearly always used a noise-limiter. Frequent users were _4 times more likely to listen to high-volume music than were infrequent users, and adolescents in practical prevocational schools were more than twice as likely to listen to high-volume music as were those attending preuniversity education. CONCLUSIONS. When using MP3 players, adolescents are very likely to engage in risky listening behaviors and are unlikely to seek protection. Frequent MP3 player use is an indicator of other risky listening behaviors, such as listening at high volumes and failing to use noise-limiter
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