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71.
Genetically engineered (GE) crops are subject to regulatory oversight to ensure their safety for humans and the environment. Their approval in the European Union (EU) starts with an application in a given Member State followed by a scientific risk assessment, and ends with a political decision‐making step (risk management). In the United States (US) approval begins with a scientific (field trial) step and ends with a ‘bureaucratic’ decision‐making step. We investigate trends for the time taken for these steps and the overall time taken for approving GE crops in the US and the EU. Our results show that from 1996–2015 the overall time trend for approval in the EU decreased and then flattened off, with an overall mean completion‐time of 1,763 days. In the US in 1998 there was a break in the trend of the overall approval time. Initially, from 1988 until 1997 the trend decreased with a mean approval time of 1,321 days; from 1998–2015, the trend almost stagnated with a mean approval time of 2,467 days.  相似文献   
72.
为建立一种快速检测锦鲤疱疹病毒(CyHV-3)的环介导等温扩增方法(LAMP),本研究根据GenBank中登录的CyHV-3 TK基因编码区序列设计了LAMP特异性引物,通过优化反应条件,建立了检测CyHV-3的LAMP方法。表明本实验建立的该检测方法具有高灵敏度、高特异性、快速和简便的特性,适用于临床上对锦鲤疱疹病毒3的快速诊断。  相似文献   
73.
Achieving the Sustainable Development Goals (SDGs) in African agriculture requires a better understanding why high levels of poverty and resource degradation persist in African agriculture despite decades of policy interventions and development projects. In this article, we hypothesize that policies need to account for the key features of the semi‐subsistence crop–livestock systems (CLS) in the region to become effective. The semi‐subsistence CLS are characterized by a high degree of biophysical and economic heterogeneity and a complex, diversified production system involving a combination of subsistence and cash crops with livestock. We investigated the potential for interventions proposed by the Government of Kenya to meet the SDGs by 2030. The analysis uses an integrated modeling approach designed to deal with the key features of these systems. A strategy that stimulates rural development, increases farm size to a sustainable level, and reduces distortions and inefficiencies in input and output markets could lead to a sustainable development pathway and achieve the SDGs for rural households dependent on CLS.  相似文献   
74.
划定永久基本农田是实现耕地保护目标的重要手段,为做好永久基本农田调整完善工作需要对基本农田现状进行调查清理,以重庆市巫山县为例,提供基于3S技术支撑的技术方法和工作思路。结果表明,以3S技术手段进行基本农田现状调查清理,能快速、准确查清基本农田现状数据中不符合基本农田划定要求的地类,能满足基本农田动态监测的需要,将更好地在基本农田划定与保护中得以应用。  相似文献   
75.
系统建立了三维仿真框架,建立了三维空间属性模型和非空间属性模型,分别对空间数据和非空间数据进行储存和管理。并建立了Hardy-Cross迭代模型和离散反馈型神经网络模型优化通风网络模型。并以C#语言来实现系统的功能。  相似文献   
76.
The financial disintermediation mechanism known as “loan-based-crowdfunding” has recently come under regulation in several countries. This competitive investment and finance vehicle is already well established in the US and British markets.By compiling empirical data from a reference crowdfunding platform, this article compares loan-based crowdfunding with traditional investment vehicles such as investment funds, equities or pension funds.The conclusion of the study is that saving through crowdfunding allows the optimization of a portfolio comprising both institutional and retail investors.  相似文献   
77.
This paper presents an analysis of the 2007-2010 Global Financial Crisis which started with the sub-prime crisis in the U.S. and became global very fast. It argues that the financial system in the United States is a complex interlocking structure of markets, institutions and regulators. The causes and culprits of the crisis, the misaligned incentives of participants and exogenous events such as the wars in Afghanistan and Iraq, precipitated failure in key markets: commodities, sub-prime housing, equities, and credit. One of the strategic consequences of this crisis is that the US will lose its dominance in world power, the frequent crises and vulnerabilities of the Neoliberalism and examines the future of capitalism. Of the alternatives to economic system, the capitalism is the most viable economic system. However, it must adopt real and efficient allocation of resources to maximize welfare of all parties and seriously address the income inequality. It must reject crony capitalism, enact true financial regulation of institutions and markets, end corporate socialism and address the system’s structural deficiencies.  相似文献   
78.
This study employs the linear and nonlinear ARDL cointegration methodologies to examine the potential symmetric and asymmetric responses of suicide rates to unemployment rates in the US from 1928 to 2013. Our results suggest that suicide rates are pro-cyclical with respect to the business cycle (measured by changes in the unemployment rate) after extensively controlling for divorce and fertility rates. Unemployment has symmetric long-run effects on the age-adjusted suicide rate and four age-specific (from ages 25–34 to 55–64) suicide rates, while the effect of an economic expansion on suicide rates for those aged over 45 is greater than the effect of an economic recession. These findings imply that the effect of an economic expansion on the decrease of the suicide rate is higher than the effect of an economic recession on the increase of the suicide rate for individuals aged over 45. Therefore, intervention designed to reduce suicidal behaviors should emphasize periods of economic recession more than periods of economic expansion for those of middle age and beyond.  相似文献   
79.
Regional corruptness in China has a positive effect on the profitability of private firms, but not that of state-owned firms. A natural experiment of exogenous trade policy change suggests that corruption may help private firms circumvent government regulation.  相似文献   
80.
Land greening in China is regarded as contributing a great deal to greening of the Earth. The phenomenon is mainly attributed to climate change, arising atmospheric CO2 and ‘Grain for Green’ (GFG) land management policies. However, limited knowledge is known how much land greening is from contributions of the GFG practice. Therefore, the study took the typical region of the GFG practice, the Loess Plateau, as the study area, and used 1982–2015 satellite-observed GIMMS3g normalized difference vegetation index (NDVI) data, ERA-Interim climatic variables (precipitation, temperature and solar radiation) and atmospheric CO2 concentration data with the help of a developed TPRC-based NDVI model to derive GFG-induced NDVI after 1999. Furthermore, this study tracked the spatial-temporal dynamics of GFG-induced NDVI and assessed contributions of the GFG practice to regional vegetation changes. Results showed that satellite-observed NDVI and TPRC-based NDVI both exhibited an increasing spatial pattern from the northwestern to southeastern Loess Plateau, but their greening trends were separately 0.0022 and 0.0009 per year in 1982–2015 (p < 0.05). Note that the satellite-observed greening trend was much steeper with a slope of 0.0056 per year after 2006 (p < 0.05). The subsequent analyses documented that GFG-induced land greening were largely responsible for the steep trend. In space, evident greening patterns began to be observed in the central Loess Plateau from 2006 to 2008, afterwards expanded towards eastern and southwestern Loess Plateau. In 2011–2015, the increase magnitude of GFG-induced land greening in the Loess Plateau averagely accounted for 8.5 % in comparison to estimated TPRC-based NDVI, but in six natural zones were various, ranging from 3.2%–15.7%. In some regions of central Loess Plateau, GFG-induced NDVI contributed even more than 20 % to vegetation increase. This study highlights that land use management contributes more to land greening dynamics over the Loess Plateau compared to climate change and arising atmospheric CO2 concentration. These findings likely provide some valuable information for curbing or enhancing specific-location vegetation changes in future regional land management and planning.  相似文献   
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