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1.
基于缺口率模型的区域粮食安全风险评估 总被引：2，自引：1，他引：1
深入分析各区域的粮食供需趋势对于保障中国未来的粮食安全至关重要。该文首先分析了影响中国粮食供需安全的风险源,提出了粮食主产区、粮食主销区和产销平衡区的粮食缺口率风险评估模型并划分了相应的风险等级,然后以洞庭湖区为例进行了实证分析。结果表明:自然灾害是影响洞庭湖区粮食供给安全的最主要因素,人口增长则是影响该区域粮食安全的普遍因素;对于大多数的县/市,资源和投入要素对未来的粮食供给将产生积极的影响。当自然灾害为一般情景或乐观情景时,洞庭湖区的粮食安全状况较为乐观;当自然灾害为悲观情景时,湖区部分县/市的粮食安全形势非常严峻。但就湖区整体而言,通过湖区内部调剂即可以满足高风险县/市的粮食需求。研究结果可为相关部门的政策制定提供客观依据,为粮食安全的风险预警和防范提供参考。 相似文献
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Foster E Matthews JN Nelson M Harris JM Mathers JC Adamson AJ 《Public health nutrition》2006,9(4):509-514
BACKGROUND: In order to obtain a measure of nutrient intake, a measure or estimate of the amount of food consumed is required. Weighing foods imposes a large burden on subjects, often resulting in underreporting. Tools are available to assist subjects in providing an estimate of portion size and these include food photographs. The application of these tools in improving portion size estimation by children has not been investigated systematically. OBJECTIVES: To assess the accuracy with which children are able to estimate food portion sizes using food photographs designed for use with adults, and to determine whether the accuracy of estimates is improved when age-appropriate portion size photographs are provided. DESIGN: Original data from three separate studies, on the accuracy of portion size estimates by adults using food photographs, by children using adult photographs and by children using age-appropriate photographs, are analysed and compared. SUBJECTS: One hundred and thirty-five adults aged 18 to 90 years and 210 children aged 4 to 11 years. RESULTS: Children's estimates of portion sizes using age-appropriate food photographs were significantly more accurate (an underestimate of 1% on average) than estimates using photographs designed for use with adults (an overestimate of 45% on average). Accuracy of children's estimates of portion size using age-appropriate photographs was not significantly different from that of adults. Children overestimated a food's weight by 18% on average and adults underestimated by 5%. CONCLUSIONS: Providing children with food photographs depicting age-appropriate portion sizes greatly increases the accuracy of portion size estimates compared with estimates using photographs designed for use with adults. 相似文献
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Boutelle KN Fulkerson JA Neumark-Sztainer D Story M French SA 《Public health nutrition》2007,10(1):16-23
OBJECTIVE: The purpose of the present study was to examine the prevalence of fast-food purchases for family meals and the associations with sociodemographic variables, dietary intake, home food environment, and weight status in adolescents and their parents. DESIGN: This study is a cross-sectional evaluation of parent interviews and adolescent surveys from Project EAT (Eating Among Teens). SUBJECTS: Subjects included 902 middle-school and high-school adolescents (53% female, 47% male) and their parents (89% female, 11% male). The adolescent population was ethnically diverse: 29% white, 24% black, 21% Asian American, 14% Hispanic and 12% other. RESULTS: Results showed that parents who reported purchasing fast food for family meals at least 3 times per week were significantly more likely than parents who reported purchasing fewer fast-food family meals to report the availability of soda pop and chips in the home. Adolescents in homes with fewer than 3 fast-food family meals per week were significantly more likely than adolescents in homes with more fast-food family meals to report having vegetables and milk served with meals at home. Fast-food purchases for family meals were positively associated with the intake of fast foods and salty snack foods for both parents and adolescents; and weight status among parents. Fast-food purchases for family meals were negatively associated with parental vegetable intake. CONCLUSIONS: Fast-food purchases may be helpful for busy families, but families need to be educated on the effects of fast food for family meals and how to choose healthier, convenient family meals. 相似文献
6.
Chinnock A 《Public health nutrition》2006,9(7):934-941
OBJECTIVE: To validate an estimated food record (EFR), using a weighed food record (WFR) as the reference method, for the determination of food consumption and nutrient intakes in a group of Costa Rican adults. DESIGN: For the WFR, all foods consumed by subjects during seven consecutive days were weighed and recorded by nutrition students. Two EFRs (a 4-day and a 3-day record) were recorded by subjects with the use of home measures and photographs to estimate amounts. SETTING: Costa Rica. SUBJECTS: Sixty adults: 30 men and 30 women; 30 living in urban and 30 in rural areas. RESULTS: The EFR gave statistically significant lower average intake estimates for energy and 12 of the 22 nutrients examined. The correlation coefficients ranged from 0.68 (polyunsaturated fats) to 0.87 (calcium). The percentage of subjects classified into the same quartile ranged from 45.0% (polyunsaturated fats) to 68.3% (vitamin B12). For all nutrients except vitamin C, 0 or 1.7% were misclassified into extreme quartiles. For food group consumption, the EFR gave statistically significant lower estimates for six of the 17 groups and correlation coefficients ranged from 0.22 (fish) to 0.93 (beverages). Greater differences in estimates of mean energy and nutrient intakes were detected among subjects from rural areas, caused in part by a tendency to underestimate the amounts of rice and beans consumed. CONCLUSION: Validation of the EFR using a WFR as the reference method gave results that compare favourably with those reported by other authors, and support the use of the EFR for dietary surveys among Costa Rican adults. 相似文献
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Thermal degradation studies of food melanoidins 总被引：1，自引：0，他引：1
Adams A Borrelli RC Fogliano V De Kimpe N 《Journal of agricultural and food chemistry》2005,53(10):4136-4142
Food melanoidins were isolated from bread crust, coffee, and tomato sauce and their composition was investigated by thermal degradation. Among the generated volatiles, important food flavor compounds were detected: in particular furans, carbonyl compounds, 1,3-dioxolanes, pyrroles, pyrazines, pyridines, thiophenes, and phenols. The results indicated that the isolated melanoidin fractions mainly consisted of compounds formed from carbohydrates and their degradation products. Besides proteins, other food constituents were incorporated in the melanoidin structure as well, such as lipid oxidation products in tomato melanoidins and phenolic compounds in coffee melanoidins. A comparison of the thermal generation of volatiles between these food-derived melanoidins and model melanoidins prepared from a single carbonyl compound and an amino acid showed that the degradation pattern of food melanoidins is quite different from that obtained from a glucose-glycine model system. 相似文献
8.
Martin Alexander 《Biological conservation》1973,5(1):15-19
The success of agriculture in the technologically-advanced countries has been accompanied by a number of environmental problems. These problems have arisen because of the need for insecticides, herbicides, and fertilizers, and the local accumulation of large quantities of animal wastes. The less-developed nations have not achieved the same success in food production, and yet it is prudent for them to give attention even now to the environmental consequences of agricultural activities. They must initiate courses of action, so that there will be the least possible environmental perturbation as they come to rely more and more on pesticides and fertilizers. Both the advanced and the less-developed countries, however, must now devote considerable effort to minimizing salinization, erosion, and soil deterioration. 相似文献
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Beyond-brand effect of television food advertisements on food choice in children: the effects of weight status 总被引：1，自引：0，他引：1
Halford JC Boyland EJ Hughes GM Stacey L McKean S Dovey TM 《Public health nutrition》2008,11(9):897-904
OBJECTIVE: To investigate the effect of television food advertising on children's food intake, specifically whether childhood obesity is related to a greater susceptibility to food promotion. DESIGN: The study was a within-subject, counterbalanced design. The children were tested on two occasions separated by two weeks. One condition involved the children viewing food advertisements followed by a cartoon, in the other condition the children viewed non-food adverts followed by the same cartoon. Following the cartoon, their food intake and choice was assessed in a standard paradigm. SETTING: The study was conducted in Liverpool, UK. SUBJECTS: Fifty-nine children (32 male, 27 female) aged 9-11 years were recruited from a UK school to participate in the study. Thirty-three children were normal-weight (NW), 15 overweight (OW) and 11 obese (OB). RESULTS: Exposure to food adverts produced substantial and significant increases in energy intake in all children (P < 0.001). The increase in intake was largest in the obese children (P = 0.04). All children increased their consumption of high-fat and/or sweet energy-dense snacks in response to the adverts (P < 0.001). In the food advert condition, total intake and the intake of these specific snack items correlated with the children's modified age- and gender-specific body mass index score. CONCLUSIONS: These data suggest that obese and overweight children are indeed more responsive to food promotion, which specifically stimulates the intake of energy-dense snacks. 相似文献
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Laboratory computer links are a key part of acquisition, movement, and interpretation of certain types of data. Remote information retrieval from databases such as the Chemical Information System provides the analyst with structural and toxicological information via a laboratory terminal. Remote processing of laboratory data by large computers permits the application of pattern recognition techniques to the solution of complex multivariate problems such as the detection of food adulteration. 相似文献
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Decker EA Warner K Richards MP Shahidi F 《Journal of agricultural and food chemistry》2005,53(10):4303-4310
Many new in vitro methods have been developed to evaluate antioxidant activity. Unfortunately, these in vitro methods often correlate poorly with the ability of compounds to inhibit oxidative deterioration of foods because the in vitro assays do not account for factors such as the physical location of the antioxidant, its interaction with other food components, and environmental conditions. To accurately evaluate the potential of antioxidants in foods, models must be developed that have the chemical, physical, and environmental conditions expected in food products. This paper outlines model systems of the evaluation of antioxidants in three types of foods: bulk oil, oil-in-water emulsions, and muscle foods. These model systems are not intended to be inclusive of all possible methods to measure lipid oxidation and antioxidant activity. However, use of these models would allow researchers to more easily compare research results from one paper to another. 相似文献
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Antibiotic residues in animal-derived food 总被引：1，自引：0，他引：1
R C Livingston 《Journal of the Association of Official Analytical Chemists》1985,68(5):966-967
Antibiotics are used extensively in food-producing animals to maintain optimal health and promote growth. The use of these drugs has the potential to leave drug-related residues such as parent drug and metabolites in meat, milk, and eggs. For those drugs that require a withholding period to ensure that residues in the food products are below established tolerances, methods of analysis are required. The majority of approved antibiotics are assayed by microbiological methods. Although these methods are suitable for screening for drug residues, they often lack the specificity and precision required of regulatory methods. Present requirements for regulatory methods have resulted in the submission of physical-chemical methods in support of New Animal Drug Applications for antibiotics. 相似文献
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Lozada M Sánchez-Castillo CP Cabrera GA Mata II Pichardo-Ontiveros E Villa AR James WP 《Public health nutrition》2008,11(9):924-933
OBJECTIVE: To establish the school eating habits of Mexican children, who are prone to obesity and later to high rates of adult chronic diseases. DESIGN: Questionnaires for students and parents with staff questionnaires and interviews. SETTING: Randomly sampled schools in a socio-economically representative district of Mexico City. SUBJECTS: Subjects were 1504 adolescents aged 10-19 years attending schools in Mexico City, 27 teachers and seven headmasters, sampled from both public and private schools and from the full range of socio-economic groups. RESULTS: Foods brought from home were of a higher nutritional quality than those purchased at school, where purchases were dominated by crisps, soft drinks and other items with high energy density. Girls were more inclined to purchase inappropriately; those from poorer homes purchased less. Private-school students irrespective of socio-economic grade brought more food from home and purchased more expensive food at school. School policies allowed food and drink vendors to market any products within the schools, which benefited financially from these activities. CONCLUSIONS: Current school food policies are conducive to amplifying the current epidemic of obesity and related adult chronic diseases, and need to change. 相似文献
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Animal pollination is one of the essential services provided by ecosystems to humans. In the face of a potential worldwide pollination crisis it is important to assess which countries may be more vulnerable in order to prioritize pollinator conservation efforts. The poverty level, the population density and the level of pollinator dependence for food provisioning are key aspects to identify vulnerable countries. We evaluate these aspects and determine the level of human food provisioning dependence on pollinators in Mexico, a developing and highly populated country. The diversity of crop species in Mexico is exceptionally high. Nearly 85% of fruit and/or seed consumed species depend to some degree on pollinators for productivity. Overall, pollinator-dependent crops generate larger income but cover a lower cultivated area and produce less volume compared to non-pollinator-dependent crops. Volume per unit area, however, as well as revenue per unit area, is much higher for pollinator-dependent crops. Native wild pollinators also play a key role in fruit or seed production of Mexican domesticated plant species and in the reproduction of many useful wild species. Thus, assuring free pollination services is particularly important in Mexico as the livelihood of a large proportion of the population exclusively and directly depends on ecosystem services for subsistence. Feasible conservation strategies involve the payment of environmental services to Ejidos (communal land tenure systems) making efforts to protect or restore plant resources and native pollinators, and the creation of new protected natural areas, which ensures food provision, mating and nesting sites for pollinators. 相似文献
16.
Inulin determination for food labeling 总被引：3，自引：0，他引：3
Inulin and oligofructose exhibit valuable nutritional and functional attributes, so they are used as supplements as soluble fiber or as macronutrient substitutes. As classic analytical methods for dietary fiber measurement are not effective, several specific methods have been proposed. These methods measure total fructans and are based on one or more enzymatic sample treatments and determination of released sugars. To determine inulin for labeling purposes, we developed an easy and rapid anion-exchange high-performance liquid chromatography (HPLC) method following water extraction of inulin. HPLC conditions included an Aminex HPX- 87C column (Bio-Rad), deionized water at 85 degrees C as the mobile phase and a refractive index detector. The tested foods included tailor-made food products containing known amounts of inulin and commercial products (cookies, milk, ice creams, cheese, and cereal bars). The average recovery was 97%, and the coefficient of variation ranged from 1.1 to 5% in the food matrixes. The obtained results showed that this method provides an easier, faster and cheaper alternative than previous techniques for determining inulin with enough accuracy and precision for routine labeling purposes by direct determination of inulin by HPLC with refractive index detection. 相似文献
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化肥与粮食安全 总被引：47，自引：8，他引：47
本文根据相关文献资料,综述了化肥在保障我国粮食安全中的作用与贡献,分析和预测了实现2010、2015、2020年粮食总产目标所需新增化肥的数量。根据近6年来我国粮食生产中出现的问题,指出要保障我国粮食安全,除了继续发展化肥工业,增加化肥用量之外,国家应采取其他相应措施,包括稳定粮食作物的种植面积(至少应维持在11000万公顷水平);调整粮食价格,保护农民种粮积极性;改善农田基本生产条件,推行节水灌溉技术,促进粮食均衡增产;适度提高粮食净进口份额等等。单纯依靠增加化肥的投入,实现国内粮食供需平衡,不仅代价太大(包括资源、环境和成本代价),市场和农民也不一定能够接受。 相似文献
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Self-administration of a food security scale by adolescents: item functioning, socio-economic position and food intakes 总被引：1，自引：0，他引：1
OBJECTIVE: To evaluate the reliability and validity of a six-item food security scale when self-administered by adolescents. DESIGN: Cross-sectional questionnaire survey including the six-item food security measure, socio-economic variables and a food-frequency questionnaire. SETTING: Representative sample of 29 schools in Trinidad. SUBJECTS: In total 1903 students aged approximately 16 years. RESULTS: Item affirmatives ranged from 514 (27%) for the 'balanced meal' item to 128 (7%) for the 'skipped or cut meals often' item and 141 (7%) for the 'hungry' item. Item-score correlations ranged from 0.444 to 0.580. Cronbach's alpha was 0.77. Relative item severities from the Rasch model ranged from -1.622 (standard error 0.043) for the 'balanced meal' item to 1.103 (0.068) for the 'skipped or cut meals often' item and 0.944 (0.062) for the 'hungry' item. The 'hungry' item gave a slightly lower relative severity in boys than girls. Food insecurity was associated with household overcrowding (adjusted odds ratio comparing highest and lowest quartiles 2.61, 95% confidence interval 1.75 to 3.91), lack of pipe-borne water in the home, low paternal education or paternal unemployment. After adjusting for socio-economic variables, food insecurity was associated with less frequent consumption of fruit (0.75, 0.60 to 0.94) or fish (0.72, 0.58 to 0.88) but more frequent consumption of biscuits or cakes (1.47, 1.02 to 2.11). CONCLUSIONS: The food security scale provides a valid, reliable measure in adolescents, although young people report being hungry but not eating relatively more frequently than adults. Food-insecure adolescents have low socio-economic position and may eat less healthy diets. 相似文献
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Mazur A Telega G Kotowicz A Małek H Jarochowicz S Gierczak B Mazurkiewicz M Pop T Zajkiewicz K Dobrucki M Mazur D 《Public health nutrition》2008,11(9):978-981
AIM: The aim of the present study was to determine the impact of food advertising in primary and secondary schools on the food purchasing habits of children. METHODS: All forty-four primary and secondary schools in Rzeszow, Poland were included in the investigation; 15000 children attend primary and secondary schools in the region. Schools were visited by members of the research team, who filled in a questionnaire regarding the type of food products displayed or advertised in the school shop window and recorded the presence of direct corporate advertising in the proximity of the school shop. Shop owners were asked to fill in a form describing food purchases by students within the week preceding the visit. The school principal (or one of teachers) completed a form describing the school's policy regarding food advertising and the sponsorship of school activities by food companies. RESULTS: Recommended foods like milk, yogurts and fruit were offered by only 40.9 % of shops. There was a correlation between foods offered in the shop and foods purchased by students. In schools, 40.9% (95% CI 25.8, 56.0%) of shop windows displayed or advertised 'healthy' foods while 9.1% (95% CI 0.0, 17.9%) of shops displayed advertisements of food companies. The difference between display of 'healthy' food in shop windows and display of food on company advertisements was significant (likelihood ratio chi2 test, P < 0.04). Type of school (primary v. secondary) was not significant factor in advertising or purchasing pattern. CONCLUSIONS: Educational programmes should be introduced in schools with the aim of improving the understanding of nutritional principles among pupils, teachers and parents. 相似文献