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OBJECTIVE: To evaluate the effects of a comprehensive physical activity (PA) promotion programme in elementary schools on children's total PA levels, leisure-time PA, physical fitness and psychosocial correlates of PA. DESIGN: A pre-test-post-test design over two school years. SETTING AND SUBJECTS: Sixteen elementary schools (764 children, mean age: 11.2 +/- 0.7 years) were randomly assigned to the intervention condition (n = 8) and the control condition (n = 8). The intervention included a health-related physical education programme, an extracurricular PA promotion programme and classroom-based PA education lessons. In the total sample, leisure-time PA, psychosocial correlates of PA and physical fitness were measured using a PA questionnaire and the Eurofit test battery. In a sub-sample, total PA levels were measured using an accelerometer. RESULTS: According to accelerometer data, children's moderate PA and moderate-to-vigorous PA (MVPA) levels decreased less in the intervention schools than in the control schools (P < 0.01). The average time spent on MVPA decreased by 9 min per day in the intervention schools compared with 33 min per day in the control schools. Children in the intervention schools reported significantly more moderate PA in leisure time than the controls (P < 0.05). No overall improvement of physical fitness and no effects on the psychosocial correlates of PA were found. CONCLUSIONS: The comprehensive PA promotion programme was successful in preventing a decline in children's total activity levels. Furthermore, the intervention increased children's PA engagement in leisure time. Therefore, implementation needs to be encouraged.  相似文献   

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BACKGROUND: Although many school-based diet and physical activity interventions have been designed and evaluated, relatively few have been tested for the after-school setting. After-school day-care programmes at either elementary schools or private locations provide a ready-made opportunity for health programmes that may be difficult to incorporate into an already-full school day. The purpose of this paper is to report on a pilot study of an after-school adaptation of the CATCH (Coordinated Approach To Child Health) elementary school programme called the CATCH Kids Club (CKC). METHODS: The CKC was pilot-tested and formatively evaluated in 16 Texas after-school programmes: eight in El Paso and eight in Austin (four intervention and four reference sites each). Evaluation consisted of direct observation of moderate to vigorous physical activity during play time, self-reported food intake and physical activity, and focus group interviews with after-school programme staff. RESULTS: Students responded well to the physical activity and snack components and were less interested in the five-module education component. Routine staff training was a key variable in achieving proper implementation; the ideal would be a full day with repeated follow-up model teaching visits. Staff turnover was a logistic issue, as was programme leader readiness and interest in conducting the programme. Strong and significant effects were observed for the physical activity but not for the education component. The results of the physical education component suggest it is feasible, effective and ready for larger-scale evaluation or dissemination.  相似文献   

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Wheat (Triticum aestivum L. cv Stacy) was grown hydroponically and 7‐day old seedlings were exposed to K+ (6, 12, 24, or 48mM) and/or norflurazon[4‐chloro‐5‐(methylamino)‐2‐(3‐(trifluoromethyl)phenyl)‐3(2H)‐pyrdazinone] (0, 0.05, 0.10, 0.20, 0.41, or 0.82 μM) for 14 days. Carotenoid content was decreased by high K+ nutrition (12–48 mM), but norflurazon‐induced inhibition of carotenogenesis was not observed at high K+ nutrition. Phytoene desaturation product concentrations were influenced by K+ nutrition.  相似文献   

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 This study was conducted to determine whether separation of particulate organic matter (POM) that is biologically labile from aggregate entrapped material improves the usefulness of POM as an index of soil C and N dynamics. The effects of conventional (CT) and no-tillage (NT) practices on POM were assessed using soils from three 10-year trials in Illinois. Loose and occluded POM in the 0–5 cm depth were separated from 1994 samples. Use of NT practices increased C and N contents at 0–5 cm relative to CT practices and those increases were most apparent in the occluded POM fraction. The correlation between total POM-N and potentially mineralizable N (PMN) was stronger than that between PMN and either the loose or occluded-POM fractions. In 1995, both the microbial biomass, estimated as chloroform-labile C (CFEC), and PMN were correlated with POM-C and N, but the relationship was weak when data (from different tillage and depth combinations) were not treated in aggregate. POM-C and CFEC were most strongly correlated in surface depths and in CT treatments. In NT 0–5 cm samples, PMN contents were similar (≈27 mg N kg–1 soil) at all sites despite notable differences in POM-N concentrations; PMN was not related to POM-N in CT samples. There was no consistent relationship between PMN and POM-N contents in 5–30 cm samples. DRFTIR spectra indicated that carbohydrates were most abundant in POM at 0–5 cm. Relatively low PMN rates and enrichment of polysaccharides in POM in the sicl soil suggest that physical protection of labile organic substrates was more important at that site than at sites with lighter textured soils. Improved fractionation and incubation techniques and alleviation of laboratory artifacts will improve our ability to relate POM quantity, distribution and composition to biologically mediated C and N dynamics occurring in the field. Received: 2 December 1999  相似文献   

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Because soil biota is influenced by a number of factors, including land use and management techniques, changing management practices could have significant effects on the soil microbial properties and processes. An experiment was conducted to investigate differences in soil microbiological properties caused by long- and short-term management practices. Intact monolith lysimeters (0.2 m2 surface area) were taken from two sites of the same soil type that had been under long-term organic or conventional crop management and were then subjected to the same 2.5-year crop rotation [winter barley (Hordeum vulgare L.), maize (Zea mais L.), lupin (Lupinus angustifolius L.), and rape (Brassica napus L. ssp. oleifera)] and two fertilizer regimes (following common organic and conventional practices). Soil samples were taken after crop harvest and analyzed for microbial biomass C and N, microbial activity (fluorescein diacetate hydrolysis, arginine deaminase activity, and dehydrogenase activity), and total C and N. The incorporation of the green manure stimulated growth and activity of the microbial communities in soils of both management histories. Soil microbial properties did not show any differences between organically and conventionally fertilized soils, indicating that crop rotation and plant type had a larger influence on the microbial biomass and enzyme activities than fertilization. Initial differences in microbial biomass declined, while the effects of farm management history were still evident in enzyme activities and total C and N. Links between enzyme activities and microbial biomass C varied depending on treatment, indicating differences in microbial community composition.  相似文献   

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OBJECTIVES: To investigate differences in reported physical activity levels and in perceived environmental and psychosocial correlates of activity between Portuguese and Belgian adults; and to analyse the relative contribution of environmental and psychosocial variables in explaining physical activity within different contexts in Portugal and Belgium. DESIGN: Cross-sectional study. SETTING: One city in Portugal (Oeiras) and one in Belgium (Ghent). SUBJECTS: In total 526 participants, 247 from Portugal and 279 from Belgium, completed the long International Physical Activity Questionnaire and a validated questionnaire on environmental and psychosocial correlates. RESULTS: For the sum of all activities of at least moderate intensity, a significantly higher mean level of activity was found in Belgian adults (P < 0.001). However, comparable percentages of the Belgian (38%) and Portuguese (42%) samples did not meet the recommendation of 30 min per day. The variance explained by environmental factors was lower (1% to 8%) than by psychosocial factors (maximum 42%). Regression analyses showed activity-specific relations with environmental variables which were analogous in both countries. Walking/cycling for transportation and walking for recreation were related to social support from family and/or friends and to walkability and walking facilities in the neighbourhood. Recreational physical activity was mainly determined by social support, self-efficacy, and perceived benefits and barriers. CONCLUSIONS: Activity campaigns addressing psychosocial determinants are needed to encourage leisure-time activity, while a combination of neighbourhood design changes and encouragement of social support in walking is warranted to increase walking in different contexts.  相似文献   

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Iron is an essential microelement for plants and can be a limiting or toxic element according to the environmental growth conditions. Plants have therefore developed a large range of physiological mechanisms to cope with Fe deficiency or Fe overload. The application of molecular biological methods have shed light on the genes, gene products and regulatory mechanisms involved in Fe stress responses, however, the acquisition of physiological data now begins to lagg behind the progress gained by molecular approaches. This review highlights and summarizes the recent progress in plant iron research achieved from the molecular level to the field scale, communicated at the “XIIth International Symposium on Iron Nutrition and Interactions in Plams” held in 2004 in Tokyo.  相似文献   

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OBJECTIVE: To investigate the relationships of two main physical activity domains (during leisure and at work) with cardiovascular risk factors and eating habits. DESIGN: Cross-sectional study. SETTING: Preventive medicine centre. SUBJECTS: In 5478 adults (32% women, aged 20-80 years) who consecutively underwent a standardised health examination, leisure-time physical activity (LTPA; i.e. non-sport leisure and sport activities), occupational physical activity (OPA) and eating habits were assessed by self-administered questionnaires. We analysed sex-specific relationships of LTPA and OPA (in quartiles) with (1) various cardiovascular risk factors and (2) eating habits using analysis of variance and logistic regression, respectively. RESULTS: In both genders, with and without adjustment for education in addition to age, LTPA was associated negatively with body mass index, body fat, waist circumference, resting heart rate, diastolic blood pressure and triglycerides, and positively associated with high-density lipoprotein cholesterol (all P < or = 0.005). OPA adjusted for age only was positively associated with most cardiovascular risk factors but these associations were not significant after further adjustment on education (except for waist circumference in women). Age- and education-adjusted LTPA was associated with increased frequency of consumption of fruits (odds ratio (OR) = 2.05, 95% confidence interval (CI) 1.68-2.52 in men; OR = 1.90, 95% CI 1.41-2.05 in women) and vegetables (OR = 1.81, 95% CI 1.48-2.21 in men; OR = 2.22, 95% CI 1.66-2.97 in women). CONCLUSIONS: The data emphasise the favourable associations of LTPA, a modifiable behaviour, with various cardiovascular risk factors and healthy eating habits. The results also suggest that the relationships of OPA with cardiovascular risk factors depend, at least in part, on socio-economic status as reflected by educational level.  相似文献   

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OBJECTIVES: To compare the prevalence of overweight and obesity among adolescents using international and ethnic-specific cut-off points and to examine patterns of physical activity and dietary behaviours. DESIGN: Cross-sectional analytical study. SETTING: Schools on Tongatapu, Vava'u and Hapa'ai islands in the Kingdom of Tonga. SUBJECTS: A total of 443 school students aged 11-16 years underwent anthropometric measures of height and weight and provided self-reported measures of physical activity and dietary behaviours.Results Mean body mass index (BMI) was higher among girls than boys (23.7 kg m(-2) vs. 21.8 kg m(-2) and tended to increase with age. A total of 36.0% of boys and 53.8% of girls were overweight or obese using the international cut-off points, whereas 25.0% of boys and 37.6% of girls were classified in this way using Polynesian-specific cut-off points. Tinned mutton or beef was the food that most participants (56.9%) reported eating once or more per day. Over half of the young people did not eat taro, fruit or vegetables at least once per day. Regular physical activity outside of school hours was reported by 20.7% of respondents, and 58.2% watched 1 h or more of television per day. Physical activity participation was the only behaviour independently associated with a lower risk of overweight or obesity.Conclusions Using Polynesian-specific cut-off points for overweight and obesity the prevalence of these conditions was still among the highest found in adolescents. The prevalence of physical inactivity and poor dietary habits indicate that risk factors for chronic disease are well established during adolescence in Tonga.  相似文献   

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龙眼钙、镁营养元素诊断技术的研究   总被引:1,自引:0,他引:1  
通过对4个果园中产量高、中、低三个等级龙眼的土壤和植株养分分析,结合龙眼产量测定,探讨龙眼钙、镁营养元素的营养诊断指标。以交换性钙和交换性镁作土壤钙、镁营养元素诊断的诊断形态,以1月份时中上部老熟秋梢(结果母枝)第2位叶的全量钙、镁作为龙眼植株钙、镁营养元素的诊断形态,分别拟定出了土壤、植株钙和镁营养的诊断指标。  相似文献   

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