Validation of ACE-FTS N2O measurements
; ; et al
in Atmospheric Chemistry and Physics (2008), 8(16), 4759-4786
The Atmospheric Chemistry Experiment (ACE), also known as SCISAT, was launched on 12 August 2003, carrying two instruments that measure vertical profiles of atmospheric constituents using the solar ... [more ▼]
The Atmospheric Chemistry Experiment (ACE), also known as SCISAT, was launched on 12 August 2003, carrying two instruments that measure vertical profiles of atmospheric constituents using the solar occultation technique. One of these instruments, the ACE Fourier Transform Spectrometer (ACE-FTS), is measuring volume mixing ratio (VMR) profiles of nitrous oxide (N2O) from the upper troposphere to the lower mesosphere at a vertical resolution of about 3-4 km. In this study, the quality of the ACE-FTS version 2.2 N2O data is assessed through comparisons with coincident measurements made by other satellite, balloon-borne, aircraft, and ground-based instruments. These consist of vertical profile comparisons with the SMR, MLS, and MIPAS satellite instruments, multiple aircraft flights of ASUR, and single balloon flights of SPIRALE and FIRS-2, and partial column comparisons with a network of ground-based Fourier Transform InfraRed spectrometers (FTIRs). Between 6 and 30 km, the mean absolute differences for the satellite comparisons lie between -42 ppbv and +17 ppbv, with most within +/- 20 ppbv. This corresponds to relative deviations from the mean that are within +/- 15%, except for comparisons with MIPAS near 30 km, for which they are as large as 22.5%. Between 18 and 30 km, the mean absolute differences for the satellite comparisons are generally within +/- 10 ppbv. From 30 to 60 km, the mean absolute differences are within +/- 4 ppbv, and are mostly between -2 and +1 ppbv. Given the small N2O VMR in this region, the relative deviations from the mean are therefore large at these altitudes, with most suggesting a negative bias in the ACE-FTS data between 30 and 50 km. In the comparisons with the FTIRs, the mean relative differences between the ACE-FTS and FTIR partial columns (which cover a mean altitude range of 14 to 27 km) are within +/- 5.6% for eleven of the twelve contributing stations. This mean relative difference is negative at ten stations, suggesting a small negative bias in the ACE-FTS partial columns over the altitude regions compared. Excellent correlation (R=0.964) is observed between the ACE-FTS and FTIR partial columns, with a slope of 1.01 and an intercept of -0.20 on the line fitted to the data. [less ▲]Detailed reference viewed: 57 (26 ULg)
Speciation analysis of Sn(II) and Sn(IV) in stannous octoate using differential pulse polarography
Hubert, Cédric ; ; Ziemons, Eric et al
Poster (2006, May)Detailed reference viewed: 39 (0 ULg)
Differences in associations of familial and nutritional factors with serum lipids between boys and girls: the Luxembourg Child Study.
Guillaume, Michèle ; ;
in American Journal of Clinical Nutrition (2000), 72(2), 384-8
BACKGROUND: Sex differences in the effects of genetic and environmental factors on circulating lipids have been examined mainly in adults, in whom the influences of sex steroid hormones are well known ... [more ▼]
BACKGROUND: Sex differences in the effects of genetic and environmental factors on circulating lipids have been examined mainly in adults, in whom the influences of sex steroid hormones are well known. OBJECTIVE: Our objective was to determine the effect of sex on genetic and environmental influences on serum lipids in prepubertal boys and girls. DESIGN: Children aged 6-8, 8-10, and 10-12 y (n = 1028) were selected at random in the Belgian province of Luxembourg, a region in Europe with a high prevalence of risk factors for cardiovascular disease and diabetes. Blood glucose and serum cholesterol, triacylglycerol, and insulin concentrations were measured, and anthropometric data and blood pressure were recorded. Familial data were obtained from standardized questionnaires. Nutritional status was obtained from a 3-d record. Participation was 70.3% of the primary cohort. RESULTS: Cholesterol, triacylglycerol, and insulin values were among the highest recorded in studies of children. In girls, cholesterol correlated positively with the energy density of intake of saturated fat (r = 0.13, P = 0.001), cholesterol (r = 0.11, P = 0.006), and protein (r = 0.12, P = 0.007) and negatively with the ratio of polyunsaturated to saturated fat intake (r = -0.14, P = 0.001) and the energy density of carbohydrate intake (r = -0.11, P = 0.019). In boys, no such relations were found. Triacylglycerol was not significantly related to nutritional factors. Consistent, independent relations were found between reported elevated cholesterol concentrations in the parental and grandparental generation and cholesterol (r = 0.101, P = 0.011) and triacylglycerol (r = 0.09, P = 0.03) in boys. No such associations were found in girls. CONCLUSION: Environmental and genetic factors may have different effects on serum cholesterol in girls and boys. [less ▲]Detailed reference viewed: 14 (5 ULg)
Socioeconomic and psychosocial conditions of parents and cardiovascular risk factors in their children: the Belgian Luxembourg Child Study III.
Guillaume, Michèle ; ; et al
in Acta Paediatrica (1999), 88(8), 866-73
Socioeconomic and psychosocial handicaps are often associated with disease. There is a large body of information on adults on such relationships, but data are sparse on children. In a cohort of 1028 boys ... [more ▼]
Socioeconomic and psychosocial handicaps are often associated with disease. There is a large body of information on adults on such relationships, but data are sparse on children. In a cohort of 1028 boys and girls, selected at random from school classes in Province de Luxembourg, a mainly rural area of Belgium, these problems were analysed in age strata of 6-8, 8-10, 10-12 years. Participation rate was 71%. Information was collected from questionnaires,. Anthropometric variables, blood pressure and glucose as well as cholesterol, triglycerides and insulin were measured in the children and related to the psychosocial and socioeconomic factors, organized into rural, psychosocial, socioeconomic and alcohol/smoking clusters of observations. Rural: Duration of living in the area of the child and parents correlated with diastolic blood pressure, particularly in boys (p < 0.01). Psychosocial: Housewives (p = 0.002) and their children (p = 0.002) had higher body mass indexes (BMI) than other mothers and their children. Sons of housewives also had higher blood pressure (systolic, p = 0.0007, diastolic, p = 0.007). Socioeconomic: Socioeconomic factors of parents (profession, unemployment) played relatively minor roles. Alcohol/smoking: Alcohol consumption was related to skinfold thickness in boys (p = 0.022), but not in girls. Girls, but not boys, with smoking parents had higher BMI (p=0.014). Multiple regression analyses suggested that psychosocial factors, such as housewives as mothers of large families, may be important for associations with cardiovascular risk factors in their children. There were apparent differences in the findings between girls and boys, suggesting that boys are more vulnerable to the impacts of the factors analysed. [less ▲]Detailed reference viewed: 11 (2 ULg)
Obesity and nutrition in children. The Belgian Luxembourg Child Study IV.
Guillaume, Michèle ; ;
in European Journal of Clinical Nutrition (1998), 52(5), 323-8
OBJECTIVE: To analyse the association between nutritional and familial factors and obesity in boys and girls. DESIGN: Randomized, cross-sectional population study. SETTING: Province de Luxembourg, Belgium ... [more ▼]
OBJECTIVE: To analyse the association between nutritional and familial factors and obesity in boys and girls. DESIGN: Randomized, cross-sectional population study. SETTING: Province de Luxembourg, Belgium. Subjects: One thousand and twenty-eight boys and girls in age strata 6-8, 8-10 and 10-12 y, comprising 70.3% of primary cohort. METHODS: Examinations included anthropometric measurements and questionnaires covering familial, socioeconomic and psychosocial factors. A three day dietary record was obtained in 955 children. This was analysed in relation to the anthropometric data. RESULTS: In comparison with similar studies from other regions and recommended allowances, the intakes of total energy, fat, particularly saturated fat and cholesterol, were high, while consumption of carbohydrate and fiber was low, as well as the polyunsaturated/saturated ratio of fat. Total energy intake showed no or weakly significant correlations with anthropometric factors. However, total fat (P=0.045) and saturated fat (P=0.0005) intake showed consistent positive correlations with body mass index (BMI, kg/m2) and skinfold thickness, with corresponding negative relationships to carbohydrate intake (P=0.034) in boys. Such relationships were also found when calculated as energy density. These associations were not statistically significant in girls. The high fat, low carbohydrate pattern of the nutritional status seemed to be more pronounced in families where the father had a low level of education (lipids, boys, P=0.0007), and where both parents were obese (saturated fat, boys, P=0.023), suggesting involvement of socioeconomic and familial factors. CONCLUSION: The lack of correlation between factors indicating obesity and total energy intake suggests that the positive energy balance causing obesity is due mainly to a low energy output. However, since energy intake measurements are imprecise, overeating can not be excluded, particularly since elevated consumption of food with high contents of fat, found in these children seems to be poorly regulated. [less ▲]Detailed reference viewed: 17 (2 ULg)
Physical activity, obesity, and cardiovascular risk factors in children. The Belgian Luxembourg Child Study II.
Guillaume, Michèle ; ; et al
in Obesity Research (1997), 5(6), 549-56
Physical activity was measured in relation to cardiovascular (CV) risk factors in a randomly selected population of 1028 children from Province de Luxembourg in Belgium, a mainly rural area with a high ... [more ▼]
Physical activity was measured in relation to cardiovascular (CV) risk factors in a randomly selected population of 1028 children from Province de Luxembourg in Belgium, a mainly rural area with a high prevalence of such risk factors among adults and children. Physical activity was estimated as participation in sport activities, a major indicator of leisure-time physical activity in schoolchildren, and physical inactivity was estimated as frequency and duration of television (TV) watching. Boys participated more frequently in sport activities than girls did (p = 0.001). A majority of the children watched TV daily. After age adjustment, bodyweight (girls, p < 0.012; boys, p < 0.027) and, in boys, body mass index (BMI) (p < 0.039) were related to days per week of TV watching. No significant relationships with other CV risk factors remained after adjustments for BMI. In analyses of independent contributions of age, TV watching, and sports activity on CV risk factors, age showed highly significant relationships. In boys, TV showed relationships with BMI (p < 0.04) and (borderline) with systolic blood pressure, independent of age and sports activity, whereas the latter was significantly related to subscapular skinfold (p < 0.04) and (borderline) with triceps skinfold and cholesterol. In girls, no significant independent contributions to risk factor associations were found. The father's education was directly associated with sports activities, whereas the mother being a housewife showed negative relationships to physical activity and positive to TV watching in their children, suggesting socioeconomic influence on the activity patterns of children. Furthermore, registrations suggested less physical activity in the most rural part of the area. It is concluded that children in this mainly rural area watch TV frequently. In boys, physical inactivity, measured both as TV watching and as registrations of sports activities, contributes independently to body fat mass. In girls, no contribution or weaker contributions of physical inactivity were found. This suggests that contributory factors leading to obesity might be different in girls and boys. [less ▲]Detailed reference viewed: 43 (7 ULg)
Cardiovascular risk factors in children from the Belgian province of Luxembourg. The Belgian Luxembourg Child Study.
Guillaume, Michèle ; ; et al
in American Journal of Epidemiology (1996), 144(9), 867-80
The Province of Luxembourg is an area in Belgium with a high prevalence of risk factors for cardiovascular disease and non-insulin-dependent diabetes mellitus among adults. In the present study, children ... [more ▼]
The Province of Luxembourg is an area in Belgium with a high prevalence of risk factors for cardiovascular disease and non-insulin-dependent diabetes mellitus among adults. In the present study, children in the age groups 6-8, 8-10, and 10-12 years were selected at random from school classes (n = 1,028), with a participation rate of 70.3%. Anthropometric factors, blood pressure, and fasting blood glucose, plasma cholesterol, triglyceride, and insulin levels were measured in 1992. All anthropometric and metabolic variables increased with age, except for waist: hip circumference ratio in boys and cholesterol in girls. In the oldest group, girls who had passed menarche were taller and heavier and had greater skinfold, body mass index, insulin, and systolic blood pressure values but lower total cholesterol levels and waist: hip ratios than girls who had not passed menarche. Boys had lower skinfolds and higher waist: hip ratios than girls in all age groups, and were significantly shorter and lighter in the oldest age group. There was no difference in body mass index between the two sexes. Girls had higher triglyceride and insulin levels in the 10- to 12-year age group, lower blood glucose values in the 8-10 and 10-12 age groups, and lower diastolic blood pressures in the 8-10 age group. Obesity, blood glucose, triglycerides, insulin, and blood pressure were highly interrelated. Cholesterol, triglycerides, insulin, and blood pressure values were all among the highest of values previously reported in other studies. The deciles of body mass index above 50 appeared to be particularly elevated, suggesting that obesity, when present, was pronounced in this population of children. These findings suggest an accumulation of genetic susceptibility to cardiovascular disease and non-insulin-dependent diabetes mellitus in this stable, ethnically homogeneous, and rather isolated part of continental Europe. [less ▲]Detailed reference viewed: 10 (5 ULg)
Familial trends of obesity through three generations: the Belgian-Luxembourg child study.
Guillaume, Michèle ; ; et al
in International Journal of Obesity (1995), 19 Suppl 3
Province de Luxembourg in Belgium is an area with clustering of obesity as well as other risk factors for cardiovascular diseases and non-insulin dependent diabetes mellitus. In this study, obesity was ... [more ▼]
Province de Luxembourg in Belgium is an area with clustering of obesity as well as other risk factors for cardiovascular diseases and non-insulin dependent diabetes mellitus. In this study, obesity was studied in a total of 1028 boys and girls in age-strata 6-8, 8-10, 10-12 years, selected at random from school classes. Participation rate was about 70%. Non-participants did not differ from participants in comparisons of school records of height and weight. Furthermore, information on birth weight, parents' height and weight was collected, as well as reported problems of obesity in grandparents. The results show a high prevalence of pronounced obesity in these children. BMIs were strongly correlated between the children and both parents. Furthermore, grandparents' obesity problems were related to the BMI of parents, and also to obesity indices in the children. Birth weights were related to current BMI of the children (in girls only for the youngest age-group), and to their mothers' BMI. It was concluded that obesity is prevalent in this area and can be traced through three generations, and seems to be discoverable already at birth. Energy intake is high and physical activity level is low in these children. However, statistical analyses suggest that familial factors exert a greater impact than environmental factors on the BMI of the children. These results, as well as the wide-spread, consistent familial clustering of obesity, traceable already at birth, suggest influence of strong genetic traits for obesity in this population. [less ▲]Detailed reference viewed: 23 (2 ULg)