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1.
The environmental degradation of lakes in China has become increasingly serious over the last 30 years and eutrophication resulting from enhanced nutrient inputs is considered a top threat. In this study, a quasi-mass balance method, net anthropogenic N inputs (NANI), was introduced to assess the human influence on N input into three typical Chinese lake basins. The resultant NANI exceeded 10 000 kg N km−2 year−1 for all three basins, and mineral fertilizers were generally the largest sources. However, rapid urbanization and shrinking agricultural production capability may significantly increase N inputs from food and feed imports. Higher percentages of NANI were observed to be exported at urban river outlets, suggesting the acceleration of NANI transfer to rivers by urbanization. Over the last decade, the N inputs have declined in the basins dominated by the fertilizer use but have increased in the basins dominated by the food and feed import. In the foreseeable future, urban areas may arise as new hotspots for nitrogen in China while fertilizer use may decline in importance in areas of high population density.

Electronic supplementary material

The online version of this article (doi:10.1007/s13280-015-0638-8) contains supplementary material, which is available to authorized users.  相似文献   
2.
从人与自然的相互关系,讨论了在发展生产的必须重视保护人类自身和生存环境,就我国建筑安全技术的现状,论述了发展科学技术是改善建筑安全技术最根本的途径,提出了当前普遍存在的安全技术在问题和需要完善的建筑施工安全法规。  相似文献   
3.
Since the end of the 1970s, the southern European countries have shown an exceptional reduction in fertility rate. From the highest levels among the developed nations, these countries dropped beneath the substitution rate level: in Greece there is an average of about 1.5 children per woman, and Italy (starting three to four years ago), with 1.3 children per woman, is now the country with the lowest fecundity rate in the world. Land-use planning in southern European small islands therefore requires substantial revision. In the areas where western civilization began, which are highly populated and have a long history, cultural and ethnic aspects of tradition are fundamental to environmental management and to the defense of historical heritage. They also place a strong value on sustaining tourism, the most relevant economic activity, that allows them to survive and maintain a high welfare level. For some decades they have had populations with a marked presence of young people and high emigration rates, but now they are fast becoming dominated by the elderly and must prepare for a period of fast reduction in youth of the workforce, while the peripheral areas of Asia and Africa are entering a sudden demographic growth phase. The demographic structure has also been deeply altered both by previous migrations and by random variations, as usually happens in all small communities. Social services for younger and older people have had to be adapted rapidly, reorganizing high-school management, hospital and health-care structures, in-house assistance, and so on. There is a need to rethink the job market and favor the immigration of highly specialized workers, which is a necessity for technical evolution. Sustainable development is constrained nowadays not only by the scarcity of natural resources, but also by the quality and quantity of human resources. Proper policies for population and land-use planning are highly correlated factors; they have to be considered with respect of these new, rapid demographic changes.  相似文献   
4.
The study contains the methodology of finding the optimal time to start the operation of a desalting plant or any other non conventional source of water for agricultural use in Israel. The essence of the methodology is the moving equilibrium price and quantity of agricultural products. The market of agricultural products is represented by a single demand curve and a supply curve which is derived from the agricultural sector production function. Both the demand for and the supply of agricultural products functions are shifting over time. The marginal value product of water is the critical value that determines the optimal time of a desalting plant. The study is static in the sense that dynamic aspects per se are not dealt with-e.g. learning by doing of building and operating desalting plants. The empirical results although used for illustrative purposes can be used as reference points for other detailed and more ‘exact’ studies on water desalination.  相似文献   
5.
BACKGROUND: Safety teams have become a popular means to recognize and prevent injuries in the workplace. In fact, organizations, such as OSHA, NIOSH, NIEHS, DOE, and the Ohio BWC, not only encourage safety teams, but have implemented them in their organizations. However, safety teams may not be legal as defined by NLRB Act Sections 2(5) and 8(a)(2). OBJECTIVE: To determine whether safety teams are illegal labor organizations. METHODS: A review of government regulations, safety programs, and safety teams was performed to create a framework of what types of safety programs/regulations are requested and/or required by a variety of government agencies. Next, these requirements were compared to existing case law on illegal labor organizations as defined by the NLRB. RESULTS: Most safety teams and programs, even those implemented by the Federal Government, are illegal labor organizations as defined by NLRB Act Sections 2(5) and 8(a)(2). CONCLUSIONS: The Federal Government needs to amend existing legislation and develop a revision of the NLRB Act that would allow safety teams to function legally in organizations without having to meet intrusive, constricting guidelines that may inhibit the value of safety teams. IMPACT ON INDUSTRY: Organizations must be aware that safety teams may be valuable in reducing job-related accidents and injuries but they may be illegal labor organizations.  相似文献   
6.
为探究河南省人类活动净磷输入状况,基于河南省18个省辖市(县辖市)行政单元统计数据,利用人类活动净磷输入量(NAPI)模型,核算河南省1990、1995、2000、2005、2010、2015和2019年人类活动净磷输入量.结果表明:在时间尺度上,1990~2015年河南省NAPI整体呈升高趋势,2015~2019年略...  相似文献   
7.
Rainfall quantity and quality, and stream and loch water quality have been monitored throughout the Loch Fleet Project. This has allowed the effects of liming of parts of the catchment to be monitored, and assessments made of the effectiveness and duration of these treatments. Rainfall over 1989–1993 fluctuated around the long-term average of 2100 mm. Over this time, year by year variations in acid or sulphate loading from deposition was evident and quite substantial. There was no trend, however, reflecting reductions in national sulphur emissions. Liming parts of the catchment in 1986 increased stream and loch water pH and calcium concentrations and reduced inorganic aluminium concentrations. Improved stream and loch water quality has been maintained for more than eight years since liming.  相似文献   
8.
A previous study has shown a marked and continuing decline in weekend births in Germany between 1988 and 2003 (Lerchl, Naturwissenschaften 92:592-594, 2005). The present study was performed to investigate the possible influence of caesarean sections (CS) on weekend birth number and on the involvement of midwives in births for all 16 German states for the year 2003. In total, data from 706,721 births were sorted according to weekday of births and state, respectively, and the weekend births avoidance rates were calculated. Weekend births were consistently less frequent than births during the week, with an average of -15.3% for all states and due to fewer births on Saturdays (-13.6%) and Sundays (-16.7%). Between the states, weekend births avoidance rates ranged from -11.6% (Bremen) to -24.2% (Saarland). The proportion of CS was 25.5% for all states, ranging from 19.2% (Sachsen and Sachsen-Anhalt) to 30.5% (Saarland). CS and weekend births avoidance rates were significantly correlated, consistent with the hypothesis that primary (planned) CS are regularly scheduled on weekdays. The number of births per midwife (BPM) was calculated according to the number of active members in the states' professional midwives' organizations. The mean number of BPM was 59.5, ranging from 45.2 (Bremen) to 82.4 (Sachsen-Anhalt). CS and BPM were significantly correlated, consistent with the hypothesis that higher CS ratios are associated with lower midwife involvement in births. It is concluded that the decline in weekend births and lower involvement of midwives are caused, at least in part, by an increased number of caesarean sections.  相似文献   
9.
语言和文化是密不可分的,在外语教学中要达到语言与文化并重的目的,就要充分重视文化导入的问题.本篇文章详细阐述了文化导入问题在英语教学中的重要性以及外语教学中文化导入的内容及方法.  相似文献   
10.
区域系统物质代谢研究——以江苏省南通市为例   总被引:11,自引:3,他引:11  
为定量地描述一个区域对其自然环境的负荷,论文利用区域系统物质代谢的方法研究了南通市全市范围内食物、能量、水、物质和废弃物的输入与输出。在研究期限内(1996~2002年),固体废弃物输出的增长率高于固体物质输入的增长率,而废水输出的增长率低于淡水输入的增长率。南通市区域代谢的速率正在持续上升。2002年非食物性资源的消耗总量是食物需求的15.8倍。化石燃料能量及电能的消耗是人体能量需求的17.9倍,光合作用固定太阳能的48.36倍。南通市区域代谢的趋势是上升的。尽管各种物质与能量的利用效率提高了,部分物质的循环利用率也上升了,但是还不足以降低其对陆地、水体和大气环境的压力。最后提出降低区域代谢脆弱性、提高代谢效率的相关建议。  相似文献   
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