Age at peak height velocity in Polish adolescents: Effect of socioeconomic factors.

Age at peak height velocity (APHV) is an indicator of maturity timing which is applicable to both sexes, and which is influenced by environmental factors. The objective of this study was to assess variation in APHV associated with several indicators of socioeconomic status (SES) in a longitudinal sample of Polish adolescents. The sample included 739 boys born in 1983 and followed annually from 12 to 16 years, and 597 girls born in 1985 and followed annually from 9 to 13 years. The height records were fitted with the SITAR model to estimate APHV. SES was estimated using principal component analysis of indicators of familial status based on parental education, family size, living conditions and household possessions. Statistical analyses included analysis of variance (one-way for general SES and three-way for parental education and family size) and Tukey post-hoc tests for unequal samples. General SES (p <.001) and family size (p < .05) significantly influenced APHV among boys, while only maternal education (p < .05) significantly influenced APHV among girls. Among youth from families of higher SES, as defined by the respective indicators, APHV was attained significantly earlier, on average, than in peers from families of lower SES. Overall, the results showed a sex-dependent effect of SES on APHV, and highlighted the influence of favorable socioeconomic conditions for optimal growth and maturation during adolescence.

Nutritional status of infants and young children in India across three decades: Analysis of five national family health surveys.

BACKGROUND: Three indicators of early childhood undernutrition and associated factors are evaluated among under-5 children in five National Family Health Surveys in India spanning 1992 to 2021. METHODS: Data for 533,495 children under 5 years of age (U-5) were analysed in the context of three commonly used indicators of early childhood undernutrition - wasting, stunting and underweight. In addition to descriptive and inferential statistics, binary logistic regression was used to estimate the effects of specific explanatory factors on the three indicators using adjusted odds ratios. RESULTS: Over the three-decade interval, stunting was reduced by 22.1% in boys and 20.9% in girls, followed by underweight, 19.3% in boys and 17.4% in girls; wasting, in contrast, was reduced to a considerably lesser extent, 2.8% in boys and 0.9% in girls. Demographic, maternal and socioeconomic factors were associated with the incidence of early childhood undernutrition, specifically among young mothers and those with less education in low-income families, and among children from Scheduled Tribes or Scheduled Castes. Stunting and underweight declined significantly over the past three decades while wasting changed negligibly. The disparity in the occurrence of early childhood undernutrition was apparent throughout socioeconomic categories and regions of India. CONCLUSIONS: The results highlight the need for special programs aimed at reducing waste among children and also the need for customized initiatives focused on the improvement of maternal education and wealth in addition to other ancillary factors related to regional variation.

Variation in body size and weight status among Hindu and Muslim Indian males born in the 1890s through the 1950s.

Hindus and Muslims represent the two largest religions in India, and also differ in nutritional status, health-related habits and standard of living associated with economic disparities. In this context, the present study considered estimated secular changes in body size, proportions, and weight status among Hindu and Muslim Indian men. The data are from anthropological surveys in the 1970s which included measurements of height, weight and sitting height of 43,950 males 18-84 years (birth years 1891-1957). Leg length was estimated; the BMI and sitting height/height ratio were calculated. Heights of men 35 + years were adjusted for estimated height loss with age. Weight status was also classified relative to WHO criteria for the BMI. Anthropometric characteristics of the two groups were compared with MANCOVA with age and geographic region as covariates. Linear regression of height on year of birth was also used to estimate secular change in each group. Heights, weights, and BMIs tended to be, on average, greater among Muslim than Hindu men at most ages, while distributions by weight status between groups were negligible. Sitting height was greater among Muslim men but estimated leg length did not differ between groups; the sitting height/height ratio thus suggested proportionally shorter legs among Muslim men. Results of the regression analyses indicated negligible differences in secular change between groups across the total span of birth years but indicated a decline in adjusted heights of men in both groups born between 1891 through 1930s and little secular change among those born in the 1930s through 1957. The variation in heights, weights and BMIs between Muslim and Hindu men at most ages suggested variation in socio-economic status and dietary habits between the groups, whereas the negligible estimated secular changes in height between groups likely reflected economic, social, and nutritional conditions during the interval of British rule and the transition to independence.

Body size and weight status of adult Indian males born in the 1890s-1950s: Age and secular change in the context of demographic, economic, and political transformation.

OBJECTIVES: To evaluate secular change in body size and weight status of adult Indian males born in 1891-1957 and surveyed in the 1970s. METHODS: Data are from Anthropological Surveys. Only men were included in the surveys due to high female illiteracy and lack of female researchers. Indian society was also strongly conservative at the time, especially in rural areas, and the measurement of women by men was not permitted. Heights and weights of 43 950 males 18-84 years (born 1891-1957) were measured. The BMI was calculated; weight status of individuals was classified relative to WHO criteria and suggested criteria for the Asia-Pacific region. Heights of men 35+ years were also adjusted for age-related stature loss. Trends in measured and adjusted heights, body weight and the BMI, and in weight status were evaluated by age groups. Linear regression of measured height and adjusted height on year of birth was used to estimate secular effects. RESULTS: Mean heights declined slightly with age to 50 years and declined sharply through 60+ years, while mean weights increased into the 40s and then declined. Mean BMIs were relatively stable from 30 to 60 years. The prevalence of thinness and normal weight was high, while that of overweight and obesity was low. Regression analyses indicated limited secular change across the total range of birth years but suggested a decline in adjusted heights among men born in 1891 through the 1930s, and little change among men born subsequently. CONCLUSIONS: Age-related trends and results of the regression analyses by year of birth indicated negligible secular change in heights of Indian men 18-84 years born between 1891 and 1957. BMIs indicated a high prevalence of thinness and normal weight and low prevalence of overweight and obesity.

Age at menarche, environmental stress, and social inequality: Evidence from Poland in the 1930s-1950s.

OBJECTIVE: To address the relationship between socioeconomic factors and age of menarche among Polish women born and reared in periods that varied considerably in environmental stresses: the Great Depression of the 1930s, the interval of World War II, and the interval of communist rule following World War II through the 1950s. METHODS: The data set included information on age at menarche and socioeconomic status (SES) of 718 women born during the Great Depression (n = 182), WWII (n = 189), and post-WWII through the 1950s (n = 347). A structured semi-parametric statistical model (generalized additive model [GAM] class) was used for analysis. An ANOVA-like linear model was used to test for marginal effects of SES-related factors and their interactions together with nonparametric seasonal effect. RESULTS: The influence of period of birth, month of birth, region of early childhood, and father's education, and the interaction between period of birth and father's education on age at menarche were statistically significant. During the economic crisis and the interval of WWII, differences in ages at menarche between the extreme categories of father's education were marked. The differences in ages at menarche between women from the lowest and highest social groups were markedly reduced among women born during the post-war interval. In addition, women born in February-March attained menarche earlier than women born in September-October. CONCLUSIONS: Unpredictable conditions associated with the economic crisis and war conditions had a stronger impact on age at menarche among women from families of lower SES compared to women from better economic circumstances. Individuals born and reared in low SES conditions likely suffered more severe deterioration across the spectrum of the standard of living and quality of life compared to those with a higher SES.

Assessment of skeletal age in youth female soccer players: Agreement between Greulich-Pyle and Fels protocols.

OBJECTIVE: The purpose of the study was to evaluate the agreement between the Fels and Greulich-Pyle methods for the assessment of skeletal age (SA) in female youth soccer players. METHODS: The sample included 441 Portuguese players 10.08-16.73 years of age who regularly participated in organized and competitive soccer. Standardized radiographs of the left hand-wrist were obtained and analyzed by an experienced examiner. SA was estimated with the Fels and Greulich-Pyle (GP) methods. Differences between SA and chronological age (CA) were used to define skeletal maturity groups: late, average and early maturing. In addition to descriptive statistics, Cohen's kappa and Lin concordance correlation coefficients were used to evaluate agreement between methods. RESULTS: Intraindividual differences in SA based on the two methods varied between 0.10 to 1.47 years among age groups with larger mean differences at older ages. Agreement of maturity classifications between methods was 74% at younger ages (under-13: kappa = 0.48; under-14: kappa = 0.39; Lin CCC = 0.68) and declined with increasing CA (under-17: 19% agreement; kappa = 0.001; Lin CCC = 0.11). About 19% of the total sample was skeletally mature with the Fels method and an SA was not assigned; in contrast, no players were skeletally mature with the GP method. CONCLUSIONS: GP SAs were systematically lower than Fels SAs among female soccer players. Intraindividual variability in SAs between methods was considerable. The findings highlight the impact of method on estimates of maturity status.

Sex-dependent effect of post-migration adaptation on height and relative lower leg length in Polish youth.

BACKGROUND: Growth in tibia length is considered to be particularly sensitive to environmental stress. AIM: To estimate the effect of parental migration status on the relative length of the tibia in their school-age children. SUBJECTS AND METHODS: Data included a nationwide random sample of 17,155 schoolchildren, 7-18 years of age, examined between 1966 and 1969 in Poland who provided information on anthropometric measurements and demographic and social characteristics. Parental migration status was based on paternal migration history. After standardisation by LMS method, z-scores of relative tibia length and z-scores of height were used for analysis. Three-way ANOVA was used to evaluate the influence of migration on tibia length-to-height ratio. RESULTS: Sons of migrants have a significantly higher tibia length-to-height ratio compared to sons of non-migrants. Children of non-migrants were taller than children of migrants among boys in medium SES and among girls in high and low SES. Relative tibia length indicated significant effects of migration among boys in all age categories and in late adolescent girls: sons of migrants had a higher ratio and daughters of migrants had a lower tibia length-to-height ratio. CONCLUSION: It is possible that migration experiences of the parents may have influenced the growth of their offspring. The results emphasise the potential importance of research addressing the impact of different types of migration on growth of children.

Life Cycle Greenhouse Gas Emissions and Costs of Production of Diesel and Jet Fuel from Municipal Solid Waste.

This paper quantifies and compares the life cycle GHG emissions and costs of production of diesel and jet fuel derived from municipal solid waste (MSW) in the United States via three thermochemical conversion pathways: conventional gasification and Fischer-Tropsch (FT middle distillate, MD), plasma gasification and Fischer-Tropsch (Plasma FT MD), and conventional gasification, catalytic alcohol synthesis, and alcohol-to-jet upgrading (ATJ MD). We use expanded system boundaries to capture the change in existing MSW use and disposal, and account for parameter uncertainty with Monte Carlo simulations. We estimate median life cycle GHG emissions of 32.9, 62.3, and 52.7 gCO2e/MJ for FT, Plasma FT and ATJ MD fuels, respectively, compared to a baseline of 90 gCO2e/MJ for conventional MD fuels. Median minimum selling prices are estimated at 0.99, 1.78, and 1.20 $ per liter with the probability of achieving a positive net present value of fuel production at market prices of 14%, 0.1% and 7% for FT, Plasma FT and ATJ MD fuels, respectively. If the societal perspective rather than an investor's perspective is evaluated, then the probability of positive net present value of fuel production increases to 93%, 67%, and 92.5% for the FT, Plasma FT, and ATJ MD fuels, respectively.

Age at menarche in Polish University students born before, during and after World War II: Economic effects.

Although the relationships between economic conditions and biological variables over the past two centuries in Poland are reasonably well-documented, the influence of economic and political disruptions, including nutritional privation, during the years immediately before, during and shortly after World War II (WWII) has received less attention. This paper considers the association between age at menarche and body size of university students born before, during and after WWII and father's level of education, a commonly used indicator of family economic status in Poland. Subjects were 518 university students surveyed between 1955 and 1972, birth years 1931 through 1951. The sample was divided into three birth cohorts: before (n=237), during (n=247) and after (n=34) WWII. Age at menarche was compared among birth cohorts, and by weight status and father's level of education. Age at menarche increased slightly but significantly among women born during WWII (14.4 yrs) compared to those born before (14.2 yrs) and after (13.9 yrs) the war. Controlling for year of birth and age of the student, age at menarche was significantly earlier in overweight (13.42±0.35 yrs) than in normal weight (14.33±0.06 yrs) and thin (14.54±0.21 yrs) women. Adjusted mean ages at menarche in small samples of overweight women did not differ by father's level of education, and were earlier than corresponding ages of thin and normal weight women. Adjusted mean ages at menarche did not differ between thin and normal weight women with fathers having primary or no education, but were slightly later in thin than in normal weight women with fathers having a vocational, secondary or higher education. Although age at menarche was associated with father's level of education, young adult weight status was a somewhat more important correlate.

Biological and environmental determinants of 12-minute run performance in youth.

BACKGROUND: The 12-minute run is a commonly used indicator of cardiorespiratory fitness in youth. Variation in growth and maturity status as potential correlates of test performance has not been systematically addressed. AIM: To evaluate biological and environmental determinants of 12-minute run performance in Portuguese youth aged 7-17 years. SUBJECTS AND METHODS: Mixed-longitudinal samples of 187 boys and 142 girls were surveyed in 1996, 1997 and 1998. The 12-minute run was the indicator of cardiorespiratory fitness. Height, body mass and five skinfolds were measured and skeletal maturity was assessed. Physical activity, socioeconomic status and area of residence were obtained with a questionnaire. Multi-level modelling was used for the analysis. RESULTS: Chronological age and sum of five skinfolds were significant predictors of 12-minute run performance. Older boys and girls ran longer distances than younger peers, while high levels of subcutaneous fat were associated with shorter running distances. Rural boys were more proficient in the 12-minute run than urban peers. Skeletal maturity, height, body mass index, physical activity and socioeconomic status were not significant predictors of 12-minute run performances. CONCLUSIONS: Age and sum of skinfolds in both sexes and rural residence in boys are significant predictors of 12-minute run performance in Portuguese youth.

Stochastic techno-economic analysis of alcohol-to-jet fuel production.

BACKGROUND: Alcohol-to-jet (ATJ) is one of the technical feasible biofuel technologies. It produces jet fuel from sugary, starchy, and lignocellulosic biomass, such as sugarcane, corn grain, and switchgrass, via fermentation of sugars to ethanol or other alcohols. This study assesses the ATJ biofuel production pathway for these three biomass feedstocks, and advances existing techno-economic analyses of biofuels in three ways. First, we incorporate technical uncertainty for all by-products and co-products though statistical linkages between conversion efficiencies and input and output levels. Second, future price uncertainty is based on case-by-case time-series estimation, and a local sensitivity analysis is conducted with respect to each uncertain variable. Third, breakeven price distributions are developed to communicate the inherent uncertainty in breakeven price. This research also considers uncertainties in utility input requirements, fuel and by-product outputs, as well as price uncertainties for all major inputs, products, and co-products. All analyses are done from the perspective of a private firm. RESULTS: The stochastic dominance results of net present values (NPV) and breakeven price distributions show that sugarcane is the lowest cost feedstock over the entire range of uncertainty with the least risks, followed by corn grain and switchgrass, with the mean breakeven jet fuel prices being $0.96/L ($3.65/gal), $1.01/L ($3.84/gal), and $1.38/L ($5.21/gal), respectively. The variation of revenues from by-products in corn grain pathway can significantly impact its profitability. Sensitivity analyses show that technical uncertainty significantly impacts breakeven price and NPV distributions. CONCLUSIONS: Technical uncertainty is critical in determining the economic performance of the ATJ fuel pathway. Technical uncertainty needs to be considered in future economic analyses. The variation of revenues from by-products plays a significant role in profitability. With the distribution of breakeven prices, potential investors can apply whatever risk preferences they like to determine an appropriate bid or breakeven price that matches their risk profile.

The costs of production of alternative jet fuel: A harmonized stochastic assessment.

This study quantifies and compares the costs of production for six alternative jet fuel pathways using consistent financial and technical assumptions. Uncertainty was propagated through the analysis using Monte Carlo simulations. The six processes assessed were HEFA, advanced fermentation, Fischer-Tropsch, aqueous phase processing, hydrothermal liquefaction, and fast pyrolysis. The results indicate that none of the six processes would be profitable in the absence of government incentives, with HEFA using yellow grease, HEFA using tallow, and FT revealing the lowest mean jet fuel prices at $0.91/liter ($0.66/liter-$1.24/liter), $1.06/liter ($0.79/liter-$1.42/liter), and $1.15/liter ($0.95/liter-$1.39/liter), respectively. This study also quantifies plant performance in the United States with a Renewable Fuel Standard policy analysis. Results indicate that some pathways could achieve positive NPV with relatively high likelihood under existing policy supports, with HEFA and FPH revealing the highest probability of positive NPV at 94.9% and 99.7%, respectively, in the best-case scenario.

Biological maturation of youth athletes: assessment and implications.

The search for talent is pervasive in youth sports. Selection/exclusion in many sports follows a maturity-related gradient largely during the interval of puberty and growth spurt. As such, there is emphasis on methods for assessing maturation. Commonly used methods for assessing status (skeletal age, secondary sex characteristics) and estimating timing (ages at peak height velocity (PHV) and menarche) in youth athletes and two relatively recent anthropometric (non-invasive) methods (status-percentage of predicted near adult height attained at observation, timing-predicted maturity offset/age at PHV) are described and evaluated. The latter methods need further validation with athletes. Currently available data on the maturity status and timing of youth athletes are subsequently summarised. Selection for sport and potential maturity-related correlates are then discussed in the context of talent development and associated models. Talent development from novice to elite is superimposed on a constantly changing base-the processes of physical growth, biological maturation and behavioural development, which occur simultaneously and interact with each other. The processes which are highly individualised also interact with the demands of a sport per se and with involved adults (coaches, trainers, administrators, parents/guardians).

Economic and environmental benefits of higher-octane gasoline.

We quantify the economic and environmental benefits of designing U.S. light-duty vehicles (LDVs) to attain higher fuel economy by utilizing higher octane (98 RON) gasoline. We use engine simulations, a review of experimental data, and drive cycle simulations to estimate the reduction in fuel consumption associated with using higher-RON gasoline in individual vehicles. Lifecycle CO2 emissions and economic impacts for the U.S. LDV fleet are estimated based on a linear-programming refinery model, a historically calibrated fleet model, and a well-to-wheels emissions analysis. We find that greater use of high-RON gasoline in appropriately tuned vehicles could reduce annual gasoline consumption in the U.S. by 3.0-4.4%. Accounting for the increase in refinery emissions from production of additional high-RON gasoline, net CO2 emissions are reduced by 19-35 Mt/y in 2040 (2.5-4.7% of total direct LDV CO2 emissions). For the strategies studied, the annual direct economic benefit is estimated to be $0.4-6.4 billion in 2040, and the annual net societal benefit including the social cost of carbon is estimated to be $1.7-8.8 billion in 2040. Adoption of a RON standard in the U.S. in place of the current antiknock index (AKI) may enable refineries to produce larger quantities of high-RON gasoline.

Allostatic load and socioeconomic status in Polish adult men.

This study considers the relationship between a cumulative index of biological dysregulation (allostatic load) and several dimensions of socioeconomic status (SES) and lifestyle in adult Polish males. The extent to which lifestyle variables can explain SES variation in allostatic load was also evaluated. Participants were 3887 occupationally active men aged 25-60 years living in cities and villages in the Silesia region of Poland. The allostatic load indicator included eleven markers: % fat (adverse nutritional intake), systolic and diastolic blood pressures (cardiovascular activity), FEV1 (lung function), erythrocyte sedimentation rate (inflammatory processes), glucose and total cholesterol (cardiovascular disease risk), total plasma protein (stress-haemoconcentration), bilirubin, creatinine clearance and alkaline phosphatase activity (hepatic and renal functions). A higher level of completed education, being married and residing in an urban area were associated with lower physiological dysregulation. The association between indicators of SES and allostatic load was not eliminated or attenuated when unhealthy lifestyle variables were included in the model. Smoking status and alcohol consumption played minimal roles in explaining the association between SES and allostatic load; physical activity, however, had a generally protective effect on allostatic load.

Maternal inactivity: 45-year trends in mothers' use of time.

OBJECTIVE: To examine 45-year trends in time use and physical activity energy expenditure (PAEE) in a nationally representative sample of US mothers. PARTICIPANTS AND METHODS: We quantified time allocation to physical activity (PA), sedentary behaviors (SED), and PAEE from 1965 to 2010 in mothers with older children (MOC) (>5 to ≤18 years) and mothers with younger children (MYC) (≤5 years). Physical activity was the sum of time allocated to housework, child care, laundry, food preparation, postmeal cleanup, and exercise. Sedentary behavior was the sum of time spent in a vehicle and using screen-based media. Physical activity energy expenditure was calculated using body weights from national surveys and metabolic equivalents. RESULTS: From 1965 to 2010, the time allocated to PA decreased by 11.1 h/wk (from 32.0 to 20.9 h/wk) in MOC and by 13.9 h/wk (from 43.6 to 29.7 h/wk) in MYC. The time spent in SED increased by 7.0 h/wk in MOC (from 17.7 to 24.7 h/wk) and increased by 5.7 h/wk in MYC (from 17.0 to 22.7 h/wk). Physical activity energy expenditure decreased by 1237.6 kcal/wk (176.8 kcal/d) in MOC (from 5835.3 to 4597.7 kcal/wk), and in MYC, PAEE decreased by 1572.5 kcal/wk (224.6 kcal/d), from 7690.5 to 6118.0 kcal/wk. CONCLUSION: There was a significant reallocation of time by mothers from PA (eg, housework) to SED (eg, watching television) between 1965 and 2010. Given the essential role of PA for health and the potential for the intergenerational transmission of obesity and obesogenic behaviors, these results suggest that maternal inactivity may be an important target for the primary prevention of chronic noncommunicable diseases and obesity.

Psychosocial correlates of physical activity in school children aged 8-10 years.

BACKGROUND: Understanding correlates of physical activity (PA) among children in different populations may contribute to fostering active lifestyles. This study considered gender differences in relationships between biologic (body mass index, BMI), demographic (socioeconomic sport status, SES) and psychosocial correlates of PA and level of PA in Portuguese primary school children. METHODS: 683 children, aged 8-10 years, from 20 different elementary schools in northern Portugal were surveyed. Weight status was classified using International Obesity Task Force (IOTF) criteria for the BMI. Family SES was estimated from school records. PA level and psychosocial correlates (attraction to PA, perceived physical competence and parental socialization) were obtained with interview and standardized questionnaires, respectively. Sex-specific hierarchical multiple regression analyses (SPSS 18.0) were conducted and included two blocks of predictor variables (biologic and demographic, and psychosocial). RESULTS: Level of PA was significantly higher in boys than girls. Enjoyment of participation in vigorous PA was positively associated with level of PA. Perceived acceptance by peers in games and sports and parental encouragement were positively and significantly related to PA in girls. Perceived physical competence was positively and significantly related to PA in boys. Weight status and SES were not associated with PA. CONCLUSIONS: Boys and girls differed in perceived attractiveness of PA and perceived physical competence, both of which influenced level of PA. Differences in perceptions may be important aspects of motivation for PA in school children.

Prevalence of traditional and novel markers of cardiovascular disease risk in Scottish adolescents: socioeconomic effects.

Information on the health status and physical activity of Scottish adolescents is limited. This study examines the prevalence of cardiovascular disease (CVD) risk in Scottish adolescents by socioeconomic status (SES). Participants were recruited from two high schools that differed in the SES of the students in attendance. The sample included 73 boys and 34 girls (16.4 ± 0.6 years). Variables included anthropometry, physical activity, physical fitness, blood pressure, diet, and 11 metabolic markers of CVD risk. Significant sex differences (P ≤ 0.01) were noted for stature, waist circumference, waist-hip ratio, physical activity, cardiorespiratory fitness, muscular power, sprint speed, and several CVD risk factors: high-density lipoprotein (HDL), low-density lipoprotein (LDL), interleukin-6 (IL-6), and C-reactive protein (CRP) levels. Boys from a lower SES had significantly higher levels of glucose and plasminogen activator inhibitor-1 (PAI-1) but lower levels of adiponectin compared with boys from a higher SES. Girls from a lower SES had significantly (P ≤ 0.01) higher glucose and PAI-1 levels but lower levels of insulin and adiponectin than girls from a higher SES. High fat diets, low physical activity levels, and elevated CRP and total cholesterol levels were the CVD risk factors most commonly identified as being at-risk levels in this cohort, regardless of sex or SES. SES differences were not consistently apparent, but several CVD risk factors were identified as elevated in this sample of adolescents, regardless of sex or SES.

Variation in sport participation, fitness and motor coordination with socioeconomic status among Flemish children.

Socioeconomic status (SES) is often indicated as a factor that influences physical activity and associated health outcomes. This study examined the relationship between SES and sport participation, morphology, fitness and motor coordination in a sample of 1955 Flemish children 6-11 years of age. Gender, age and SES-specific values for morphologic dimensions, amount and type of sport participation and fitness and motor coordination tests were compared. SES was positively and significantly associated with sport participation and sports club membership in both sexes. Although differences were not consistently significant, morphologic dimensions and tests of fitness and motor coordination showed a trend in favor of children from higher SES. The results suggest that public and local authorities should consider providing equal opportunities for children in all social strata and especially those in the lower SES to experience the beneficial effects of sport participation through which they can enhance levels of physical fitness and motor coordination.

Public health, climate, and economic impacts of desulfurizing jet fuel.

In jurisdictions including the US and the EU ground transportation and marine fuels have recently been required to contain lower concentrations of sulfur, which has resulted in reduced atmospheric SO(x) emissions. In contrast, the maximum sulfur content of aviation fuel has remained unchanged at 3000 ppm (although sulfur levels average 600 ppm in practice). We assess the costs and benefits of a potential ultra-low sulfur (15 ppm) jet fuel standard ("ULSJ"). We estimate that global implementation of ULSJ will cost US$1-4bn per year and prevent 900-4000 air quality-related premature mortalities per year. Radiative forcing associated with reduction in atmospheric sulfate, nitrate, and ammonium loading is estimated at +3.4 mW/m(2) (equivalent to about 1/10th of the warming due to CO(2) emissions from aviation) and ULSJ increases life cycle CO(2) emissions by approximately 2%. The public health benefits are dominated by the reduction in cruise SO(x) emissions, so a key uncertainty is the atmospheric modeling of vertical transport of pollution from cruise altitudes to the ground. Comparisons of modeled and measured vertical profiles of CO, PAN, O(3), and (7)Be indicate that this uncertainty is low relative to uncertainties regarding the value of statistical life and the toxicity of fine particulate matter.