共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
3.
甲型H1N1流感的已知与未知 总被引:1,自引:0,他引:1
《农村工作通讯》2009,(10):52-52
甲型H1N1流感发展至今,全球确诊病例数呈现不断增加态势。甲型H1N1流感病毒到底呈现怎样的特性,人们对它已有了哪些了解?还有哪些未解之谜? 相似文献
4.
为了适应当今社会大学生创业的需要,项目组成员精心成立奥罗拉便利店项目,并正在实践中。本文详细分析7-11便利店成功的经营与管理经验,希望借此能给我国奶茶业未来发展提供相应建议。 相似文献
5.
6.
7.
Rejoinder to the comment by Andrew Dorward and Ephraim Chirwa on Jayne,T. S., D. Mather,N. Mason,and J. Ricker‐Gilbert. 2013. How do fertilizer subsidy program affect total fertilizer use in sub‐Saharan Africa? Crowding out,diversion, and benefit/cost assessments. Agricultural Economics, 44(6), 687–703 下载免费PDF全文
T. S. Jayne David Mather Nicole M. Mason Jacob Ricker‐Gilbert Eric W. Crawford 《Agricultural Economics》2015,46(6):745-755
8.
10.
11.
近年来,N市Z镇通过实施“一揽子机制、N项措施和4类发展路径”推动本地农村人才建设,但仍存在相关政策支持不足、政策体系不健全、培养的内容及形式与实际需求不相符、培养机制不完善、基础设施落后、发展空间不足、人才流失不断加剧等问题。为完善Z镇农村人才的队伍建设,可从强化顶层设计、健全农村人才政策体系、完善农村人才培养机制、提升农村人才培养实效、改善农村基础设施条件、为农村人才发展提供有力保障等方面入手,加强农村人才队伍建设,为乡村振兴提供强有力的人才保障。 相似文献
12.
13.
14.
This paper provides an original accounting of changes in livestock production efficiency per livestock category in historical perspective and connects livestock consumption with land requirements and virtual land trade. We use France as a demonstration study and account for productivity changes in terms of energy. Feed rations composition are reconstructed per livestock production and feed crop group over time to account for changes in land use in relation to dietary changes. Land requirements for consumption in France dropped by 28% over the study period besides an increase by 35% of the human population and by 53% of the livestock consumption. The two-fold increase in agricultural productivity is due, for half, to energy conversion efficiency improvements and for half to agricultural yields. Overall, the livestock energy conversion efficiency increased by 45% from 1961 to 2010, poultry gained 84%, pork 17%, sheep&goat 67% and cattle 27%. The feed share of oilcrops and cereals in animal rations doubled against a drop by 35% of feed from pastures. Virtual land imports for oilcrops in relation to livestock consumption in France today amount to 0.9 million ha against a maximum of 1.9 million ha in 1979. Besides its dependence on oilcrops imports, the French livestock sector displays net virtual land exports ranging from about 2.5–5.3 million ha per year over the study period. Gross virtual land trade is today five times higher than the net virtual trade. The difference highlights the share of circular product loops in increasingly integrated agricultural markets at the international scale. 相似文献
15.
城市扩张驱动力分析及GM(1,N)预测 总被引:4,自引:1,他引:4
根据柳州市十多年的城市规模统计以及相关社会经济资料,分析其城市规模变化趋势,运用灰色系统分析法得出城市规模变化的主要驱动力为社会系统压力、经济发展、投资和工业发展,并在此基础上建立柳州市城市规模GM(1,N)模型,预测柳州市城市规模。经检验,该模型具有良好的质量,对于研究其他城市规模的发展具有积极的指导意义。 相似文献
16.
17.
19.
This viewpoint paper presents a reaction to the article by Brandt et al. (2016). It highlights the complexities inherent to the attribution of deforestation impacts to policy interventions when using remote-sensing data. This critique argues that in the context of the Congo a suite of factors (i.e., population density in particular) other than those considered by Brandt et al. (e.g., type of forest, distance from roads and markets) play essential roles in determining the fates of forests. It also contends that care is needed when making decisions regarding which units will be included in the comparison group so that contextual factors and on-the-ground information are properly considered (e.g., when logging operations are inactive or when a concession is used for ‘conservation’ purposes). Finally, it proposes that a focus on an analysis of deforestation rates for a given level of timber production might be a metric that more accurately represents one aspect of the consequences of forest management, which should also consider the appraisal of trade-offs associated with a larger set of social, financial and ecological objectives. 相似文献
20.
Scenario analysis of urban dynamics from spatial land use models can support urban, planning and policy. An integrated modeling approach, linking assessment of urban spatial dynamics, was applied to the Santiago Metropolitan Area (SMA). The integrated land use change model combines, a logistic regression model, Markov chain, and cellular automata. This model was calibrated with data, from 1975 to 2010, and was used to make predictions for the years 2030 and 2045, using two datasets of, urban and non-urban explanatory variables. Urban change estimates showed the highest fit during the, model calibration phase. The true-positive proportion and standard Kappa value (κ) were of 99% and, 0.87 respectively when validating against an urban cover reference map from 2010. Urban growth was, equal to +27,000 ha (72%) for the period 1975–2010, and the city of Santiago is projected to, reach approximately 93,000 ha by 2045 (+43% from 2010). In the SMA the most important, urban growth pattern is peri-urban development, referring to widespread boundaries and higher, fragmentation in peripheral municipalities. Predictions for 2030 estimate that ∼15% of the projected, urban expansion will occur outside the boundary set by the current Regulatory Plan proposal. These, results demonstrate the capacity of the integrated model to establish comparisons with urban plans, and its utility to explain both the amount and constraints of urban growth. The integrated approach of, urban dynamic assessment using land use modeling is useful for spatiotemporal representation of, distinct urban development forms. 相似文献