90 research outputs found

    Some remarks about simulation of cosmic ray phenomena with use of nuclear interaction models based on the current SPS proton-antiproton data

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    The x-y controversy is studied by introducing models with as many features (except for x and y distributions) in common, as possible, to avoid an extrapolation problem, only primary energies of 500 TeV are considered. To prove the point, Monte Carlo simulations are performed of EAS generated by 500 TeV vertical primary protons. Four different nuclear interaction models were used. Two of them are described elsewhere. Two are: (1) Model M-Y00 - with inclusive x and y distributions behaving in a scaling way; and (2) Model M-F00 - at and below ISR energies (1 TeV in Lab) exactly equivalent to the above, then gradually changing to provide the distributions in rapidity at 155 TeV as given by SPS proton-antiproton. This was achieved by gradual decrease in the scale unit in x distributions of produced secondaries, as interaction energy increases. Other modifications to the M-Y00 model were made

    Electrons, muons and hadrons in extensive air showers and how do they depend on nuclear interaction model, part 2

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    Some of the results of Monte Carlo simulations of extensive air showers for nuclear interactions models are presented. The most significant part of scaling violation effect is generated by the inclusion of rising cross-section. Among the models considered the lowest value for Eo/N(max) is obtained when rapidly rising cross-section and charge exchange are both included (model R-F01). The value is still 1.38 GeV/electron. Except at the highest energies, the sensitivity to atomic mass of the primary is greater than to specific assumptions about multiple production

    Psychosocial Characteristics and Gestational Weight Change among Overweight, African American Pregnant Women

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    Objectives. To describe psychosocial factors identified as contributors of weight gain in the general population and to examine the relationship between these factors and gestational weight gain among low socioeconomic status, African American, overweight pregnant women. Methods. African American women (n=120) with a pregravid body mass index β‰₯25 kg/m2 completed measures of eating, sleep, and depressed mood between 14 and 24 weeks of gestation. Weight was tracked. Descriptive statistics, correlations, and linear regression modeling were used to characterize the sample and examine predictors of gestational weight gain. Results. Four percent screened positive for night eating syndrome, with 32% consuming at least 25% of their daily caloric intake after dinner (evening hyperphagia). None met criteria for binge eating disorder; 4% reported occasional binge episodes. Cognitive restraint over eating was low. Participants slept 7.1 (SD=1.9) h per night and reported 4.3 (SD=3.6) awakenings per week; 18% reported some level of depressed mood. Night and binge eating were related to each other, sleep quality, and depressed mood. Eating due to cravings was the only psychosocial variable to predict gestational weight gain. Conclusions. Depressed mood, night eating, and nighttime awakenings were common in this cohort, while cognitive restraint over eating was low. Most psychosocial variables were not predictive of excess gestational weight gain

    Prospective association between objective measures of childhood motor coordination and sedentary behaviour in adolescence and adulthood

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    BACKGROUND: Higher levels of gross motor coordination are positively associated with physical activity in childhood, but little is known about how they relate to sedentary behaviour. The aim of this study was to investigate the longitudinal association between gross motor coordination at childhood and sedentary behaviour in adolescence and adulthood. METHODS: Data were from the 1970 British Cohort Study (the age 10, 16, and 42-year surveys). At age 10 the participant's mother provided information on how often participants watched TV and played sports and a health visitor administered several tests to assess gross motor coordination. At aged 16 and 42-years participants reported their daily screen and TV time, respectively, and physical activity status. We examined associations between gross motor coordination at age 10 with sedentary behaviour and physical activity at age 16 and 42, using logistic regression. RESULTS: In multivariable models, higher levels of gross motor coordination were associated with lower odds of high screen time (n = 3073; OR 0.79, 95% CI 0.64, 0.98) at 16-years although no associations with physical activity were observed (OR 1.16, 95% CI 0.93, 1.44). Similar associations were observed with TV time in adulthood when participants were aged 42, and in addition high gross motor coordination was also associated with physical activity participation (n = 4879; OR 1.18, 95 % CI 1.02, 1.36). CONCLUSIONS: Intervention efforts to increase physical activity participation and reduce sedentary behaviour over the life course may be best targeted towards children with low gross motor coordination

    Suspected Motor Problems and Low Preference for Active Play in Childhood Are Associated with Physical Inactivity and Low Fitness in Adolescence

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    Background - This prospective longitudinal study investigates whether suspected motor problems and low preference for active play in childhood are associated with physical inactivity and low cardiorespiratory fitness in adolescence. Methodology/Principal Findings - The study sample consisted of the Northern Finland Birth Cohort 1986 (NFBC 1986) composed of 5,767 children whose parents responded to a postal inquiry concerning their children's motor skills at age 8 years and who themselves reported their physical activity at age 16 years. Cardiorespiratory fitness was measured with a cycle ergometer test at age 16 years. Odds ratios (OR) and their 95% confidence intervals (95% CI) for the level of physical activity and fitness were obtained from multinomial logistic regression and adjusted for socio-economic position and body mass index. Low preference for active play in childhood was associated with physical inactivity (boys: OR 3.31, 95% CI 2.42–4.53; girls: OR 1.79, 95% CI 1.36–2.36) and low cardiorespiratory fitness (boys: OR 1.87, 95% CI 1.27–2.74; girls: OR 1.52, 95% CI 1.09–2.11) in adolescence. Suspected gross (OR 2.16, 95% CI 1.33–3.49) and fine (OR 1.88, 95% CI 1.35–2.60) motor problems were associated with physical inactivity among boys. Children with suspected motor problems and low preference for active play tended to have an even higher risk of physical inactivity in adolescence. Conclusions/Significance - Low preference for active play in childhood was associated with physical inactivity and low cardiorespiratory fitness in adolescence. Furthermore, children with suspected motor problems and low preference for active play tended to have an even higher risk of physical inactivity in adolescence. Identification of children who do not prefer active play and who have motor problems may allow targeted interventions to support their motor learning and participation in active play and thereby promote their physical activity and fitness in later life.peerReviewe

    Gestational Weight Gain and Body Mass Index inΒ Children: Results from Three German Cohort Studies

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    Previous studies suggested potential priming effects of gestational weight gain (GWG) on offspring's body composition in later life. However, consistency of these effects in normal weight, overweight and obese mothers is less clear. We combined the individual data of three German cohorts and assessed associations of total and excessive GWG (as defined by criteria of the Institute of Medicine) with offspring's mean body mass index (BMI) standard deviation scores (SDS) and overweight at the age of 5-6 years (total: nβ€Š=β€Š6,254). Quantile regression was used to examine potentially different effects on different parts of the BMI SDS distribution. All models were adjusted for birth weight, maternal age and maternal smoking during pregnancy and stratified by maternal pre-pregnancy weight status. In adjusted models, positive associations of total and excessive GWG with mean BMI SDS and overweight were observed only in children of non- overweight mothers. For example, excessive GWG was associated with a mean increase of 0.08 (95% CI: 0.01, 0.15) units of BMI SDS (0.13 (0.02, 0.24) kg/m(2) of 'real' BMI) in children of normal-weight mothers. The effects of total and excessive GWG on BMI SDS increased for higher- BMI children of normal-weight mothers. Increased GWG is likely to be associated with overweight in offspring of non-overweight mothers

    Opportunities for primary and secondary prevention of excess gestational weight gain: General Practitioners' perspectives

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    BackgroundThe impact of excess gestational weight gain (GWG) on maternal and child health outcomes is well documented. Understanding how health care providers view and manage GWG may assist with influencing healthy gestational weight outcomes. This study aimed to assess General Practitioner\u27s (GPs) perspectives regarding the management and assessment of GWG and to understand how GPs can be best supported to provide healthy GWG advice to pregnant women.MethodsDescriptive qualitative research methods utilising semi - structured interview questions to assess GPs perspectives and management of GWG. GPs participating in shared antenatal care in Geelong, Victoria and Sydney, New South Wales were invited to participate in semi - structured, individual interviews via telephone or in person. Interviews were digitally recorded and transcribed verbatim. Data was analysed utilising thematic analysis for common emerging themes.ResultsTwenty eight GPs participated, 14 from each state. Common themes emerged relating to awareness of the implications of excess GWG, advice regarding weight gain, regularity of gestational weighing by GPs, options for GPs to seek support to provide healthy lifestyle behaviour advice and barriers to engaging pregnant women about their weight. GPs perspectives concerning excess GWG were varied. They frequently acknowledged maternal and child health complications resulting from excess GWG yet weighing practices and GWG advice appeared to be inconsistent. The preferred support option to promote healthy weight was referral to allied health practitioners yet GPs noted that cost and limited access were barriers to achieving this.ConclusionsGPs were aware of the importance of healthy GWG yet routine weighing was not standard practice for diverse reasons. Management of GWG and perspectives of the issue varied widely. Time efficient and cost effective interventions may assist GPs in ensuring women are supported in achieving healthy GWG to provide optimal maternal and infant health outcomes.<br /

    Can We Modify the Intrauterine Environment to Halt the Intergenerational Cycle of Obesity?

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    Child obesity is a global epidemic whose development is rooted in complex and multi-factorial interactions. Once established, obesity is difficult to reverse and epidemiological, animal model, and experimental studies have provided strong evidence implicating the intrauterine environment in downstream obesity. This review focuses on the interplay between maternal obesity, gestational weight gain and lifestyle behaviours, which may act independently or in combination, to perpetuate the intergenerational cycle of obesity. The gestational period, is a crucial time of growth, development and physiological change in mother and child. This provides a window of opportunity for intervention via maternal nutrition and/or physical activity that may induce beneficial physiological alternations in the fetus that are mediated through favourable adaptations to in utero environmental stimuli. Evidence in the emerging field of epigenetics suggests that chronic, sub-clinical perturbations during pregnancy may affect fetal phenotype and long-term human data from ongoing randomized controlled trials will further aid in establishing the science behind ones predisposition to positive energy balance
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