The impacts of biofuels targets on land‐use change and food supply: A global CGE assessment

We analyze the long‐term impacts of large‐scale expansion of biofuels on land‐use change, food supply and prices, and the overall economy in various countries or regions using a multi‐country, multi‐sector global computable general equilibrium model augmented with an explicit land‐use module and detailed biofuel sectors. We find that an expansion of biofuel production to meet the existing or even higher targets in various countries would slightly reduce GDP at the global level but with mixed effects across countries or regions. Significant land re‐allocation would take place with notable decreases in forest and pasture lands in a few countries. The expansion of biofuels would cause a moderate decrease in world food supply and more significant decreases in developing countries like India and Sub‐Saharan Africa. Feedstock commodities (sugar, corn and oil seeds) would experience significant increases in their prices in 2020, but other price changes are small.     

Occupational Safety and the Shift from Common to Individual Fishing Quotas in the Gulf of Mexico

We investigate and measure how a shift from a regime of common property to one of private ownership of fishing rights affected the safety of commercial fishing activity. To deal with overfishing and stock depletion of red snapper and grouper‐tilefish in the Gulf of Mexico (GOM), various regulatory controls, most notably common quotas and seasonal closures, were introduced in the early 1990s. The resulting “fishing derbies” led to an increased number of accidents and fatalities. We show that the subsequently implemented individual fishing quota programs led to a sharp reduction in the number of fatalities, in large part because of lower pressure to make risky trip decisions, in particular under adverse weather conditions.     

Environmental Efficiency and the Optimal Size of Chinese Cities

The spatial distribution of population and economic activities has important impacts on both economic growth and the environment. This paper uses a slack‐based measure to estimate the total factor environmental efficiency (TFEE) of 286 Chinese prefectural‐and‐above cities for the period 2002–2013. In particular, the relationship between city size and TFEE is investigated. The findings also show an inverted U‐shaped relationship between TFEE and city size, which implies an optimal city size of 16.68 million residents in China. According to this estimate, most Chinese cities may be undersized due to the migration restrictions of the hukou registration system and, hence, suffer from great environmental efficiency losses. The estimated low average TFEE value of Chinese cities also suggests the large potential for efficiency improvement. Thus, government policies should focus on relaxing migration restrictions and encouraging the development of large cities.     

What are the Determinants of Large‐scale Farming in China?

The Chinese Government has increased its focus on expanding farm scale to promote agricultural development since 2010. A series of favorable polices has been adopted to support large‐scale farming. Using a multivariate probit model and 2015 and 2016 rural household survey data, the present paper examines the factors that influence small farmers' decision to become large‐scale farmers. The empirical regression results suggest that the decision to become a large‐scale farmer is significantly influenced by household human capital, cooperative membership, marketing channels, land‐transfer contracts and government policies. However, the influence of these factors differs with respect to becoming large‐scale grain and non‐grain farmers. These results imply that policy tools should target these factors and the appropriate group of small‐scale farmers. Generally, both central and local governments should promote large‐scale farming by enhancing rural households' human capital, improving marketing channels and providing agricultural social services, as well as encouraging returning migrant workers to engage in large‐scale farming.     

Stopping deforestation in the Amazon: Trade-off between ecological and economic targets?

Stopping Deforestation in the Amazon: Trade-off between Ecological and Economic Targets? —Using a computable general equilibrium model the paper analyzes the regional, sectoral and macroeconomic dimension of Brazil’s “deforestation problem”. It is shown that macroeconomic reform is not in conflict with conservation policies. Therefore, there is no need for compensation payments but rather for improving the effectiveness of conservation policies by macroeconomic reform. The analysis also shows that regional conservation policies are generally superior to sectoral conservation policies.     

DS18B20在数字温度计的应用

随着时代的进步和发展,单片机技术已经普及到我们生活、工作、科研、各个领域,已经成为一种比较成熟的技术。本文主要介绍了一个基于89S51单片机利用数字温度传感器DS18820开发测温系统,该系统可以方便的实现温度采集和显示,并可根据需要任意设定上下限报警温度,它使用起来相当方便,具有精度高、量程宽、灵敏度高、体积小、功耗低等优点,适合于我们日常生活和工、农业生产中的温度测量。DS18820与AT89C51结合实现最简温度检测系统,该系统结构简单,抗干扰能力强,适合于恶劣环境下进行现场温度测量,有广泛的应用前景。     

低损耗高Q值声表面波谐振器

介绍了低损耗高Q值声表面瑞利波和声表面横波谐振器的原理、结构、制作和关键的设计参数，以及实验结果。其中双端声表面瑞利波谐振器的有载Q值可达5000以上，无载Q值可达20000以上。     

The Economic Benefits of the Biological Control of Rabbits in Australia, 1950–2011

Wild European rabbits are serious agricultural and environmental pests in Australia; myxoma virus and rabbit haemorrhagic disease virus have been used as biocontrol agents to reduce impacts. We review the literature on changes in rabbit numbers together with associated reports on the economic benefits from controlling rabbits on agricultural production. By using loss–expenditure frontier models in with and without biocontrol scenarios, it is conservatively estimated that biological control of rabbits produced a benefit of A$70 billion (2011 A$ terms) for agricultural industries over the last 60 years. The consequences for ongoing rabbit control and research investment are discussed.     

Evolution of Urban–rural Living Standards Inequality in Thailand: 1990–2006

The present study examines the developments in urban–rural living standard inequality in Thailand from 1990 to 2006 using a methodology that allows for the identification of individual contributors to changes in inequality. We also propose a method to analyze the changes over time in urban–rural living standards. We find that the urban–rural gap in living standards in Thailand has narrowed substantially since the early 1990s, both at the mean and especially for households in the upper part of the expenditure distribution; however, the narrowing of the gap at the bottom of the expenditure distribution has been negligible. The study also identifies the main individual contributors to changes over time in living standards between urban and rural areas in Thailand.