Reproducibility of systematic literature reviews on food, nutrition, physical activity and endometrial cancer

OBJECTIVE: Despite the increasing dependence on systematic reviews to summarise the literature and to issue public health recommendations, the formal assessment of the reliability of conclusions emerging from systematic reviews has received little attention. The main goal of the present study was to evaluate whether two independent centres, in two continents, draw similar conclusions regarding the association of food, nutrition and physical activity and endometrial cancer, when provided with the same general instructions and with similar resources. DESIGN: The assessment of reproducibility concentrated on four main areas: (1) paper search and selection; (2) assignment of study design; (3) inclusion of papers; and (4) individual studies selected for meta-analysis and the summary risk estimate obtained. RESULTS: In total 310 relevant papers were identified, 166 (54 %) were included by both centres. Of the remaining 144 papers, 72 (50 %) were retrieved in the searches of one centre and not the other (54 in centre A, 18 in centre B) and 72 were retrieved in both searches but regarded as relevant by only one of the centres (52 in centre A, 20 in centre B). Of papers included by both centres, 80 % were allocated the same study design. Agreement for inclusion of cohort-type and casekey' papers was 87 %. Summary risk estimates from meta-analyses were similar. CONCLUSIONS: Transparency of process and explicit detailed procedures are necessary parts of a systematic review and crucial for the reader to interpret its findings.     

A comprehensive physical activity promotion programme at elementary school: the effects on physical activity, physical fitness and psychosocial correlates of physical activity

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.     

Policy councils on food, nutrition and physical activity: the UK as a case study

International experience of Policy Councils on food and nutrition has developed over recent decades but they have not received the attention that is due to them. The 1992 International Conference on Nutrition recommended that governments create Food Policy Councils but few have been created. There has been more experience in local and sub-national policy councils, particularly in North America. Developing country experience of attempting to improve food policy integration stems from the 1970s. The UK's House of Commons' (Parliamentary) Health Committee, in its 2004 report on obesity, reviewed current policy determinants of the rise in obesity, concluding that national food and health policy lacked coherence, integration and effectiveness. To address this vacuum, it proposed the creation of a new 'Council of Nutrition and Physical Activity to improve co-ordination and inject independent thinking into strategy'. The case for creating such a Council in the UK is reviewed, as are possible organisational options, functions and remit. A Council could be created under the forthcoming Public Health Act. The purpose of the new Council would be to provide independent advice and strategic advice as well as monitor the linkages between policies on food, nutrition and physical activity, noting their environmental implications.     

The CATCH Kids Club: a pilot after-school study for improving elementary students' nutrition and physical activity

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.     

Influence of potassium nutrition on norflurazon activity in wheat

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.     

粉煤灰堆场植被恢复过程的养分效应及重金属变化特征

对黑龙江省鸡西滴道矸石电厂粉煤灰堆场自然植被恢复方式与人工恢复方式中粉煤灰基质养分、重金属含量变化特征进行研究,分析不同恢复方式对基质养分、重金属污染物状况的影响规律。结果表明：1）粉煤灰基质中养分含量极不均衡,有机质、全氮、速效氮、速效磷等营养元素严重缺乏,速效钾含量较丰富;2）粉煤灰在自然堆放过程中存在养分流失现象,全效性养分的流失程度高于速效性养分的流失程度;3）人工植被恢复过程极显著地改善了表层基质的养分状况,有机质含量增加459.28%,全氮增加238.46%,全磷增加131.4%,速效性N、P、K含量分别提高30.17%、56.29%、22.58%;4）粉煤灰堆场主要超标重金属为Hg,客土沙棘恢复方式有效降低了粉煤灰基质重金属含量,Hg、Cu、Cr含量相对自然恢复草地分别降低了66.93%6、8.82%和16.09%。     

现代气候变化情景下土壤微生物活性和碳动态研究进展

Microbial activities are affected by a myriad of factors with end points involved in nutrient cycling and carbon sequestration issues. Because of their prominent role in the global carbon balance and their possible role in carbon sequestration, soil microbes are very important organisms in relation to global climate changes. This review focuses mainly on the responses of soil microbes to climate changes and subsequent effects on soil carbon dynamics. An overview table regarding extracellular enzyme activities (EAA) with all relevant literature data summarizes the effects of different ecosystems under various experimental treatments on EAA. Increasing temperature, altered soil moisture regimes, and elevated carbon dioxide significantly affect directly or indirectly soil microbial activities. High temperature regimes can increase the microbial activities which can provide positive feedback to climate change, whereas lower moisture condition in pedosystem can negate the increase, although the interactive effects still remain unanswered. Shifts in soil microbial community in response to climate change have been determined by gene probing, phospholipid fatty acid analysis (PLFA), terminal restriction length polymorphism (TRFLP), and denaturing gradient gel electrophoresis (DGGE), but in a recent investigations, omic technological interventions have enabled determination of the shift in soil microbe community at a taxa level, which can provide very important inputs for modeling C sequestration process. The intricacy and diversity of the soil microbial population and how it responds to climate change are big challenges, but new molecular and stable isotope probing tools are being developed for linking fluctuations in microbial diversity to ecosystem function.     

药用植物连作障碍研究评述和发展透视

连作障碍作为现代农业生产中较普遍的问题,在药用植物栽培生产中表现尤为严重,据统计约70%以块根类入药的药用植物在种植过程中都存在严重的连作障碍问题。连作障碍已经成为制约药用植物品质和发展的关键性因素。本研究从药用植物连作障碍问题研究现状出发,分析了当前药用植物连作障碍形成的三大共性问题,即根系分泌物诱导根际土壤酸化、根际微生物群落结构失衡和植株病毒病严重,具体体现在:根系分泌物诱导根际土壤微生物差异性演化、土传病原菌的化感互作、根际微生物区系的失衡加大土壤酸化、根际病原菌增多和有益菌减少导致的土存真菌病害加重、病毒病伴生和发展。并分析了土壤灭菌法、功能微生物调控、作物多样性栽培和生物质炭改良的根际调控策略在减缓药用植物连作障碍中的潜在作用。作者呼吁从事连作障碍研究的工作者应重视从根际生态学角度出发,以土壤食物网为切入点,应用现代系统生物学和化学生态学技术与方法,全面系统探究根系分泌物介导下植物-土壤-微生物的相互作用过程与机制,并着重关注土壤线虫和土壤病毒在连作障碍发生发展中的生态位关系,以深入阐明连作介导土壤酸化的生态学机制和病原菌响应根系分泌物的协同进化机理,在此基础上,采用多种根际调控相结合的策略减缓连作障碍问题,全面考虑经济、社会和生态效益,做到"生态预防为主、综合治理为要"。     

不同离子对水稻田土壤甲烷氧化活性影响的研究

研究了矿质元素不同的阴离子和阳离子与黄松泥田水稻土壤氧化甲烷活性之间的相关性。结果表明 ,不同的阴离子和阳离子对甲烷氧化活性的影响有显著性差异 ,不同浓度的同一种阴离子或阳离子对甲烷氧化活性的影响也有显著性差异。Na+较K+对土壤甲烷氧化活性具有更强的抑制作用。NH4+和NO2-可与甲烷氧化竞争土壤中的分子氧而有明显的抑制作用。Cr3+对微生物具毒性而影响土壤的甲烷氧化。阴离子PO43-和CO32-无明显影响。这种影响的差异性不仅与阴离子和阳离子本身的理化特征有关 ,而且与土壤对阳离子的吸附力及阴离子与土壤的相互作用强度有关。土壤理化特性同样影响阴离子和阳离子对甲烷氧化活性影响的强弱     

波尔多液营养保护剂对花生黄化症的矫治及生长效应的影响

选用山东省花生主产区的代表性石灰性土壤,通过土培试验的方法,研究了3种不同形态铁的波尔多液营养保护剂BNPP-NFe、BNPP-EFe、BNPP-RFe和美国铜基杀菌剂Kocide 4种可湿性粉剂矫治花生缺铁黄化症,以及对花生生长效应的影响。结果表明,与CK(喷清水)相比,喷施BNPP-NFe后,花生叶绿素、活性铁、全铁含量都有显著提高,并且BNPP-NFe、BNPP-EFe和BNPP-RFe处理的产量比CK分别提高92％～115％、67％～98％以及90％～94％。BNPP-NFe处理与Kocide处理相比,花生叶片活性铁和全铁含量差异显著,分别提高77.12％～139%以及29.01％～120%,产量提高27.5％～37.6％。3种不同的波尔多液营养保护剂以BNPP-NFe效果最好,且优于美国Kocide产品。     

Effects of past and current crop management on soil microbial biomass and activity

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.     

Tillage practice influences on the physical protection, bioavailability and composition of particulate organic matter

 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     

Environmental and psychosocial correlates of physical activity in Portuguese and Belgian adults

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.