DESERTIFICATION IN CHINA: STATUS, TRENDS, AND STRATEGIES

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Seeing the forest for the trees: Local-level resource use and forest restitution in postsocialist Bulgaria

Recent legislation for the restitution of ownership rights to, and subsequent management of, formerly privately owned forests in postsocialist Bulgaria has focused largely albeit not exclusively on the restored forests from the perspective of timber production, that is, `forest' equals `harvestable timber resource'. Using ethnographic data collected in rural Rhodope Mountain communities, this paper presents a local-level perspective on forests and forest use, including the meaning that forests hold for local residents as a source of non-timber forest products such as mushrooms and medicinal plants, of animal pasture, and of firewood for household heating and cooking. This local social perspective is then contrasted with the timber-resource focus of the forestry legislation and subsequent planning for forest use. The scale of forest ownership – in part a function of the restitution legislation – is also addressed in relation to the practicalities of resource management. Generally, the paper demonstrates a mismatch between the postsocialist forestry legislation and local practice and conditions with regard to forests and the natural resources therein. This revised version was published online in July 2006 with corrections to the Cover Date.     

Territories and identities in Jerusalem

Jerusalem is a city of many contrasts. It is a historical-symbolic city, revered by Muslims, Christians and Jews. However, its citizens segregate ethno-nationally, culturally and socially, into different identity groups: Jews and Arabs, Haredi (`ultra-Orthodox') and secular Jews, and lower and upper class socio-economic groups. This essay focuses on how political and social struggles over territories reshape the nature of the identities of four distinct groups in Jerusalem. These are ethno-national groups (Israeli Jews and Palestinian Arabs), cultural groups (ultra-Orthodox Jews, in Hebrew Haredim (zealots), and non-Orthodox Jews), ethno-social groups (disadvantaged groups mainly of oriental descent, in Hebrew Mizrahim and advantaged groups) and economic and ecological groups (the business sector and inhabitants of private residential areas of the city). Thus, long-term historical processes have produced distinct ethno-national, cultural and social identity groups, which occupy specific territories within Jerusalem. The different groups have endowed their territory with dissimilar geopolitical, cultural, and economic meanings and played a major role in the reconstruction of national, cultural, social and ecological identities in the city. The city of Jerusalem is not only a spiritual centre associated with age-long dreams for peace and justice, it is also a violent city, rife with tensions and conflicts, a symbol of national, cultural, economic and ecological struggles. Perhaps the greatest challenge facing all those concerned about its future is whether Jerusalem's universal image of a spiritual, tolerant and just city can overcome its current, particularistic and conflict ridden image.     

福建省酸雨形势与污染损耗及其控制对策

本文介绍了福建省近年来的酸雨形势，分析其特征与成因，并对其酸雨污染的影响与损耗进行评估，提出解决福建省酸雨问题的对策措施．     

The potential value of improved ocean observation systems in the Gulf of Mexico

A number of coastal and ocean observation systems exist throughout the Gulf of Mexico (GOM), but the network of systems is not currently linked or integrated and at present not fully implemented. The network of local systems are diverse, typically involving unique mandates and several different funding sources at various levels of permanence. The purpose of this paper is to describe the ocean observation systems that currently exist in the GOM, and to identify and quantify the expected economic benefits that may result from the implementation of an integrated regional network. Improved ocean observation systems are expected to reduce the uncertainty of ocean/weather forecasting and to enhance the value of ocean/weather information throughout the Gulf region. The source of benefits and the size of activity from which improved ocean observation benefits may be derived are estimated for private sector, non-market, and public sector activities categorized according to marine transportation, commercial fishing, recreational fishing, search and rescue operations, and pollution management. The benefits of improved ocean observation systems to energy exploration, development, and production activities are estimated, and a discussion of potential benefits to lightering activities, environmental monitoring, royalty payments, and engineering design are highlighted.     

Linking teaching and research in undergraduate physical geography papers: The role of fieldwork

Undergraduate teaching should be informed by research. The extent to which this is the case and how this is best practised is the subject of this paper. Learning strategies that seek to embed research within the undergraduate programme from an introductory level are discussed. The degree of success in these strategies is informed by input from postgraduate students who have ‘come through the ranks’. Their views, obtained via a focus group, suggest that research is rigorously embedded at every level of the programme and is most clearly linked to teaching in research-based third-year papers with a strong fieldwork component.     

Evaluation of water quality and protection strategies of water resources in arid–semiarid climates: a case study in the Yuxi River Valley of Northern Shaanxi Province, China

Water resource structure is one of the most important factors that constrain the economic development in arid–semiarid areas. Sustainable use of water requires a thorough understanding of the local geology and hydrology and developing of effective protection strategies. Discussed in this paper is a study on the phreatic water quality of the Yuxi River Valley of Shaanxi Province, China. The Yuxi River Valley passes through the Shaanbei energy base, which demands large quantities of high-quality water. A total of 129 water samples were collected in 4,938 km² in a recent study to delineate the areas with water suitable for drinking, industrial, and agricultural usage and areas with poor quality. The study indicates that the poor quality of water contains high concentrations of NH⁴⁺ and NO₂⁻¹, indicating possible contamination by waste disposal in the nearby cities and towns. A series of strategies are proposed to protect the water in the Yuxi River Valley, including proper treatment and recycling of the waste water in the cities and towns, strict control of the waste-water discharge from any new factories and mines, and prevention of groundwater contamination by wastes containing heavy metals.     

农户后顾生计来源及其居民点整合研究 ——基于重庆市西部郊区白林村471户农户调查

农户生计资产决定着农户生计方式选择与生计策略行为,作为当前农户主要消费性投资行为的农村居民点建设消费受制于农户所拥有的生计资产量,基于此引导农户的居民点建设消费行为、开展农村居民点整合已成为当前提高农村土地利用效率、改善农户生产生活条件的关键。研究选取重庆市沙坪坝区白林村为样点,采用“PRA (Participatory Rural Appraisal) +3S”相结合的方法,以地理坐标为标识码,建立农户属性数据与地块的空间数据相链接的“农户-土地”数据库。运用该数据库,构建农户生计资产量化指标体系,量化农户生计资产进行农户分化,剖析不同农户的后顾生计来源及其住居意愿,开展农村居民点整合。结果表明,农户生计资产的配置结构差异明显,8%的农户各项资产产值高于平均水平,23%的农户各项资产产值处于中等水平;以农户拥有的自然资产产值为主辅以其他各项资产产值,将农户划分为农业多样化发展型(16%)、农业专业化发展型(8%)、兼业化发展型(23%)、非农多样化发展型(31%) 和非农专业化发展型(22%) 5 类;根据不同生计来源农户的住居意愿并结合国家与地方发展战略,构建了社区型(非农多样化发展型与非农专业化发展型)、组团型(农业专业化发展型)、块状型(农业多样化发展型) 和带状型(兼业化发展型) 4 种农村居民点整合方式。     

胡杨和灰杨的叶绿素荧光参数及茎水势对塔克拉玛干沙漠腹地生境的响应

通过测定胡杨（Populus euphratica）、灰杨（Populus pruinosa）叶绿素荧光参数和茎水势,研究了二者成龄叶片样本的电子传递和光能的吸收、分配和耗散对塔克拉玛干沙漠腹地生境的适应特征。结果表明,无论清晨弱光下还是正午强光下,胡杨茎水势均比灰杨低,胡杨具有更强的吸水能力;在光合有效辐射不十分高的晴天内,胡杨的光系统Ⅱ的电子传递速率ETR对时间的积分面积大于灰杨,表明胡杨的日能量积累量大于灰杨;胡杨的非光化学淬灭系数NPQ呈单峰状,灰杨呈双峰态,正午的光合有效辐射对灰杨造成了一定程度的光抑制;午后14时（光合有效辐射最大,PAR=1216 μmo·m-2·s-1）,胡杨Y(NO)∶Y(NPQ)∶Y(Ⅱ)=18%∶50%∶32%,主动耗散能量的比例占到50%,表现了极强的抗性,而灰杨3者比例为Y(NO)∶Y(NPQ)∶Y(Ⅱ)=16%∶19%∶65%,通过提高主动散热（NPQ机制）比例,胡杨较灰杨具有更强的强光适应能力。胡杨与灰杨皆可通过提高激发能热耗散比例适应较高光合有效辐射,但胡杨较灰杨具有更强的调节能力和抗性。     

进化策略及其改进算法在深基坑支护优化设计中的应用研究

进化策略是一种新的求解全局最优问题的方法,应用该方法对深基坑支护结构进行了优化设计的初步研究。针对进化策略在处理非线性函数的优化问题及高维优化问题时在收敛速度和收敛性方面存在的不足,将禁止搜索与有向搜索相结合,提出了一种快速进化策略算法,有效地克服了传统进化策略的缺点。工程实例分析研究表明,进化策略不受设计空间的可微性、连续性等限制,特别适合于求解支护工程这类具有离散设计变量和非确定性因素的工程设计问题;改进的进化策略具有更好的收敛性,有极强的避免局部极值的全局优化能力。