Introduction: immigrants and transnational experiences in world cities

Today, in the early 21st century, goods, information, services, financial capital and human beings are flowing across national borders at an ever-accelerating rate. In this context, transnationalism has become a key paradigm in the study of international migration and urbanism. This theme issue on “Immigrants and transnational experiences in world cities” explores these new trends in contemporary international migration, with respect to transnational communities and geographies, in articles grouped according to four themes: international migration and world cities; highly-skilled and low-skilled immigrants; economic impacts; and immigrant experiences in world cities.     

桂林市及近郊土壤汞的分布和污染研究

通过对桂林市区及近郊表层、底层土壤汞的系统取样,测试和编图,阐明了本区土壤汞的分布规律,确定了土壤汞的污染区段和污染程度。在上述工作的基础上,结合基岩汞测量、热释汞方法和重金属元素组合分析,对土壤汞的来源、污染无比汞的赋存状态进行了初步探讨。     

群桩沉降及周围土体沉降的计算

把群桩等代为一个大单桩,将群桩与周围土体的相互作用简化为侧表面上的面荷载和分布在底面的面荷载.基于Mincujn 应力解,通过积分求得该等代大单桩桩侧摩阻力与桩端阻力对桩周土体中任一点的附加应力,根据分层总和法可得到群桩自身沉降以及周围土体任一点的竖向沉降.为验证本文方法,对上海2个工程实例进行计算分析并与实测数据进行对比.结果表明本方法可以很好地计算群桩自身沉降以及桩周土体沉降.     

Economic restructuring, housing policy and Maori housing in Northland, New Zealand

Since 1984 the New Zealand economy has experienced a significant phase of economic restructuring which has had a differential impact on various sectors, regions and social groups within the economy. This paper examines the extent to which economic change has affected the marginalized status of Maori households in the predominantly rural region of Northland. The social implications of economic restructuring are assessed by focusing on the housing circumstances of this indigenous people. Using a newly developed Maori housing database, we argue that relatively progressive housing policies, developed in the 1980s, have failed to address the housing problems of Maori and that the recent reliance on ‘market’ mechanisms to meet housing needs is likely to exacerbate problems of housing access and cost.     

沈阳郊区表层土壤有机氯农药残留特征及风险评价

利用GC-ECD定量测定了沈阳郊区21个表层土壤样品中有机氯农药(OCPs)的含量,并对其残留特征、可能来源及生态风险进行了分析。结果表明,研究区表层土壤中OCPs的检出率达到95.2%,残留量最高值达到111.67 ng·g-1,平均值26.91 ng·g-1,其中以六六六(HCHs)和滴滴涕(DDTs)为主。与国内其他城市土壤中OCPs含量相比,沈阳郊区表层土壤HCHs和DDTs残留属于较低水平,但HCB残留属于较高水平。研究区OCPs的来源解析表明OCPs主要来自环境中的早期残留和近期林丹的使用,六氯苯(HCB)的来源还应包括工业生产。相关性分析说明土壤中总有机碳和水溶盐含量是影响OCPs残留的重要因素。生态风险评价显示表层土壤中DDTs类有机氯农药对该区生物可能仍存在生态风险。     

上海郊区土壤-沉积物剖面中铀、 钍分布特征及影响因素分析

对上海郊区不同地貌单元的 12个土壤-沉积物剖面进行铀、钍含量调查的结果显示,各剖面铀、
钍的含量均处于中国土壤背景值范围之内,且表土和下部沉积物之间不存在明显差异,反映尚未遭受到人为污
染。铀、钍含量的分布与地貌环境 （ 包括物质来源、物质颗粒组成、有机碳含量以及pH值等）密切相关：贝
壳砂堤和火成岩残丘附近剖面的铀、钍最为富集,而新形成的潮滩剖面中铀、钍含量最低。在砂质沉积物占主
导且pH值较大的河口沙岛和新滨海平原环境中,铀、钍含量随有机碳含量增加而上升,而在泥质沉积物占主导
且pH值偏低的淡水湖沼区,铀、钍含量和有机质含量呈相反关系。     

Settlement patterns in Judea and Samaria

The settlement patterns of the West Bank (Judea and Samaria) reflect the physical and cultural makeup of the area. Physical factors are most important in conditioning the layout and size of settlements. The dominance of fairly uniform Arab population reduces, to some extent, the significance of the cultural factor for the purpose of differentiating patterns, but recent Jewish settlement has introduced distinct new forms. The patterns can also be related to the age of the settlement. This applies to the Arab communities and not only to the Jewish ones. It is shown that patterns can be identified and explained by the intersection of the time factor and a certain langscape factor. Nine different patterns (two Jewish, six Arab and one mixed) are identified and explained.This article is the outgrowth of research which was supported by the Bar-Ilan University Research Authority and the Moskowitz Cathedra for Research on the Land of Israel.     

北京郊区土壤中DDT（滴滴涕）残留调查及评价

北京郊区农田表层土壤中DDT（滴滴涕）有不同程度的检出,∑DDTs含量介于2．7008～292．4021μg／kg之间,平均值为41．6227μg／kg。总体而言,DDT及其代谢物的残留量处于较低水平。样品中p,p′DDE和p,p′-DDT是DDT的主要残留物,p,p′-DDD／p,p′-DDE质量比为0-1．2730,大部分小于1,说明DDT主要降解为DDE类化合物,由此推断北京郊区的土地利用较多处于好氧环境中。（DDE＋DDD）／DDT的比值在0．1044～1．4688之间,均值之比为0．3557,母体DDT含量占优势,DDT农药施用时间很短。经初步分析,北京郊区土壤中DDT的风险较低,但从食物链角度的风险评价结果来看,土壤中的DDT仍有一定的风险。     

住房保障研究进展与趋势

采用文献回顾法和归纳法综述了国内外有关住房保障的研究进展和趋势。从国内外相近研究比较、国内研究热点及存在问题、国内研究维度三个方面得出结论:国外学者侧重住房保障体系内部运行机制的应用研究;而基于我国住房保障建设尚处于不成熟阶段的现状,国内学者旨在探索完善住房保障制度体系,研究热点主要集中在理论研究、经验总结以及制度构想三个方面;国内研究普遍存在定量分析不足、研究维度单一等问题。研究提出,将我国住房保障制度中的两种基本形式——住房补贴和保障性住房政策同时纳入研究框架,构建多层次性与可选择性相匹配的住房保障制度,实现住房保障制度的可持续性与连续性,应成为下一步研究的重点。     

北京市城近郊区地下水的环境同位素研究

应用环境同位素方法,研究北京城近郊区地下水演化规律。沿北京市永定河冲洪积扇地下水流动方向取样15组(D、18O、T、14C及全分析),对所取水样进行D、18O、T、14C分析,并确定地下水同位素年龄。运用地下水14C和T含量在垂向和水平方向变化的结果,验证了地下水的流向并计算了地下水的流速变化范围为5·02~62·63m/a,从山前至平原浅层地下水径流速度逐渐变小,反映了地下水水平径流强度逐渐减弱,地下水交替逐渐变差;浅层孔隙水以垂向交替为主,深层孔隙水以水平径流为主。对地下水D、18O之间的关系进行分析,从而判断地下水的补给来源等。     

济南市区泉水与东、西郊岩溶水水力联系研究

为查明济南市区泉水与西郊、东郊岩溶水的水力联系,从地层结构、水动力场角度,结合抽水试验、示踪试验和水化学分析等方法研究泉水与岩溶水之间的关系。结果表明,济南市区和西郊之间的刘长山—郎茂山—万灵山一带存在地下水径流通道。刘长山北侧槐苑广场—九中—十四中一带,在埋深350 m处揭露连续的岩溶含水地层,并存在垂向径流通道,市区泉水和西郊岩溶水通过刘长山北侧侵入岩体接触带以下的三山子组含水层连通。市区与东郊之间的燕翅山—七里河一带受舌状侵入岩体的影响,两侧地下水流场存在差异,但山东大学洪楼校区以北埋深485 m处揭露连续的岩溶含水地层,市区泉水和东郊岩溶水可通过侵入岩体接触带以下的三山子组含水层连通。水化学分析结果表明市区泉水与西郊、东郊岩溶水水化学类型一致,具有相同的演化环境。     

上海近远郊地区建设用地减量化差异探析

目前上海出台了建设用地减量化三年实施计划,各区县在深入推进中产生了很多差异。本文通过比较分析法,从近郊地区和远郊地区两个视角展开研究,发现在政府态度方面,前者积极支持减量化,后者被动推进减量化;在"198"工业用地减量化方面,前者推进积极有序,后者缺乏动力;在宅基地减量化方面,前者农民对其比较排斥,后者农民对其总体支持。结合访谈结果和实地调查案例,本文对这些差异化现象的原因进行解释。研究表明,制定近远郊差别化的减量化政策是下一步"减量化"实施的重要保证。     

Settlement and sustainability in the Polish Sudetes

The paper summarises the history of human settlement in the Sudetes from the Bronze Age. A more intensive stage was reached in the Middle Ages when settlers from the west established new villages deep in the mountain valleys. By the beginning of the 20th century the Sudetes were already overpopulated but after a near-complete ethnic replacement from a German to a Polish population in 1945–8, population continued to grow until the 1980s. However, the economic system was hardly sustainable by this time. There were many polluting industries in the region and massive transboundary pollution from adjacent areas of Czechoslovakia and Germany had a devastating effect on the forests. Moreover, subsidised state agriculture placed heavy pressure on vulnerable mountain grazings. Since 1989 there has been a process of deindustrialisation in the Sudetes and surrounding areas and, with the disappearance of the state farms and the reduction in subsidies, agriculture is now better adjusted to the natural potential and is complemented by a promising start with agrotourism. The population of the region is growing relatively slowly (0.8% per annum 1956–1999), with the rural areas now in decline. A sustainable future for the region is now a possibility, but while there is a consensus for continued environmental reconstruction, supported by alternative economies, this will have to be carefully managed in the years ahead when EU accession may bring heavier development pressures than those evident at the moment. This revised version was published online in July 2006 with corrections to the Cover Date.     

Geographical distribution of the Soviet-Jewish new immigrants in Israel

The State of Israel is facing now one of the most difficult absorption challenges it has ever had. About 250.000 Soviet-Jewish immigrants have arrived to the country since 1989 and another million are waiting in the Soviet Union for immigration. A direct absorption plan around an absorption basket of a few thousand dollar per family of three for the first year enables the immigrants to choose their place of habitation. They concentrate in big cities and veteran settlements along the coastal plain where employment possibilities are better. This trend is against the government's plans to direct them to peripheral regions. The current mass-immigration creates an unexpected change in the population and settlement pattern of Israel.     

Textural characteristics of dust fallout and potential effect on public health in Kuwait City and suburbs

The textural and mineralogical characteristics of the dust fallout along with the potential effect on human health were investigated at 12 locations in Kuwait City and suburbs during March 2006–February 2007. Mineralogically, the dust comprises mostly calcite and quartz with grain size ranging from 1 to 25 μm. Chemically, elements such as Ca, Fe, Mg, and Al are the dominant ones with the highest amount of average percentage concentration 12.89% for Ca. Results showed that humans in the 12 sites are being exposed to different ranges of average percentage concentrations of minerals such as calcite (15.00–51.80%), quartz (26.40–66.9%), albite (6.30–17.30%), dolomite (1.20–10.20%), and gypsum (0.00–6.4%), where site K3 recorded the lowest average concentrations for calcite, dolomite, and gypsum and the highest for quartz, and albite. The elements Ca, Fe, Mg, Al, K, Zn, Na, Cr, and Cd recorded ranges of (5.845–12.890%), (0.946–3.141%), (0.752–2.513%), (0.545–2.261%), (0.059–0.307%), (0.004–0.792%), (0.003–0.018%), (0.001–0.005%) and <0.0004%, respectively. Inhalation of such concentrations of calcite particles may cause coughing, sneezing, and nasal irritation, and in cases of chronic exposure to excessive oral doses of calcite may produce alkalosis and hypercalcemia. Quartz can have potentially serious respiratory effects following long-term exposure (1 year or more) which is the case here in our study. Comparing with international and local standards, it is highly likely that harmful and hazardous effects on the human body are being experienced by long-term exposure to dust fallout in Kuwait.     

Subsidized mortgage loans and housing affordability in Poland

While a couple of decades ago homeownership used to be a privilege of the few, nowadays most households in developed countries are living in their own four walls. One of the reasons behind this shift are government policies aimed at promoting homeownership and making it more financially feasible. Among these policies, there is a wide range of instruments reducing the costs of mortgage loan interest. Recently, the promotion of homeownership has also become an important issue in some of the former socialist countries. An example of that is a policy of the Polish government called “Family’s own home”. The aim of this policy was to provide financial support for young households who are particularly vulnerable to the difficult housing situation in Poland. Due to huge price increases between 2006 and 2008, and in connection with a short supply of rental housing, many households have been unable to find an affordable dwelling in recent years. The “Family’s own home” policy, initiated in 2007, was the government’s response to this problem. The purpose of this paper is to investigate the outcomes of this policy, which was terminated at the end of 2012 because of a public finance crisis. Three research questions are addressed: (1) what was the relationship between government support and residential construction, housing prices, and mortgage loan interest rate, (2) what was the spatial distribution of government support, and (3) how was it related to the spatial distribution of housing prices, incomes, and housing affordability?     

北京城近郊区土壤中Cd的释放、形态转化与演变趋势

在对北京城近郊区主要类型土壤(潮土和褐土)中Cd形态分析的基础上,研究pH与土壤中Cd的释放量及其形态转化的关系.结果表明潮土和褐土中Cd的释放量曲线都呈下凹的弧形,在pH=6～7之间释放量最低.pH对土壤中Cd释放的影响,其本质是土壤中Cd的化学形态发生了变化,各形态间的转化以水溶态为中介体.所有的形态转化中,pH对交换态和碳酸盐结合态影响最大,且这两者之间的转化对生物有效量起决定性作用.进而根据北京城近郊区土壤中生物有效Cd的分布状况,结合北京市近12年监测的大气pH值,对北京城近郊区土壤Cd污染进行预警.