大北京人口分布格局与多中心性测度

为了弄清北京大都市区的发展格局与趋势,运用空间自相关分析、空间基尼系数、人口—空间基尼系数对大北京都市圈的人口空间格局、就业空间格局等进行分析。研究结果表明:外来人口和常住人口分布的Moran I分别为0.25和0.31,P值小于0.001,二者均呈显著的空间自相关;北京市的常住人口仍然呈显著的单中心聚集形态,外围中心并未形成强势的人口聚集热点,距离中心约40-60km处的西北、东北和西南方向上形成了三个冷点区域;外来人口热点集中在以月坛街道为中心、大约40km为半径的圆形区域,该区域基本覆盖了东城区、西城区、朝阳区的行政面积,海淀区、丰台区的东半部分,以及昌平区、顺义区、通州区、大兴区的靠近城市中心部分,冷点区域则更靠近边缘。对大北京的背景区域——京津冀都市圈的多中心性分析表明,该区域首位特征突出,多中心性不明显:该区域33.6%和35%的城镇人口与非农就业集中在北京,专业技术人员有60%聚集于北京和天津;专业技术人员中文学艺术工作人员和新闻、出版、文化艺术工作人员的空间基尼系数最大,分别有79%和73%的人员聚集在北京,空间基尼系数达到0.36和0.29;科学研究人员的聚集也比较显著,空间基尼系数达到0.18,有60%以上汇聚北京;2000年以来整个区域的人口基尼系数逐年递增。因此,京津冀区域的发展应从三个层次着手:在北京行政区内培育新城热点,促进城市的多中心化发展;在京津冀重要交通廊道上推进轴线空间建设,保持集聚经济优势;在区域空间中促进新城镇建设,协调发展区域经济网络。     

Bridging the sanitation gap between disaster relief and development

By interpreting disasters as opportunities to initiate the fulfilment of development needs, realise the vulnerability of the affected community and environment, and extend the legacy of relief funds and effort, this paper builds upon the concept linking relief, rehabilitation and development (LRRD) in the sanitation sector. It aims to use a composite of case studies to devise a framework for a semi‐hypothetical scenario to identify critical components and generic processes for a LRRD action plan. The scenario is based on a latrine wetland sanitation system in a Muslim community. Several sub‐frameworks are developed: (i) latrine design; (ii) assessment of human waste treatment; (iii) connective sanitation promotion strategy; and (iv) ecological systems and environmental services for sanitation and development. This scenario illustrates the complex issues involved in LRRD in sanitation work and provides technical notes and references for a legacy plan for disaster relief and development.     

A bottom-up clustering approach to identify bus driving patterns and to develop bus driving cycles for Hong Kong

Bus transport has been an important mode taking up a significant share of urban travel demand and thus the corresponding impacts on the environment are of great concerns. Use of driving cycles to evaluate the environmental impacts of buses has attracted much attention in recent years worldwide. The franchised bus service is currently playing important roles in the public transport system in Hong Kong; however, there is no driving cycle developed specifically for them. A set of bus driving cycle was therefore developed using a bottom-up approach where driving data on the bus network with mixed characteristics were collected. Using the Ward’s method for clustering, the collected data were then categorized into three clusters representing distinct franchised bus route patterns in Hong Kong. Driving cycles were then developed for each route pattern including (i) congested urban routes with closely spaced bus stops and traffic junctions; (ii) inter-district routes containing a number of stop-and-go activities and a significant portion of smoother high speed driving; and (iii) early morning express routes and mid-night routes connecting remote residential areas and urban areas. These cycles highlighted the unique low-speed and aggressive driving characteristics of bus transport in Hong Kong with frequent stop-and-go activities. The findings from this study would definitely be helpful in assessing the exhaust emissions, fuel consumptions as well as energy consumptions of bus transport. The bottom-up clustering approach adopted in this study would also be useful in identifying specific driving patterns based on vehicle speed trip data with mixed driving characteristics. It is believed that this approach is especially suitable for assessing fixed route public transport modes with mixed driving characteristics.

     

Cover Image

The cover image is based on the Original Article Noninvasive prenatal paternity testing by means of SNP-based targeted sequencing by Jacqueline Chor Wing Tam et al., https://doi.org/10.1002/pd.5595 .

     

Monitoring long-term variation of aerosol composition: a dual particle-size approach applied to Hong Kong

The 1990's time series in Hong Kong for various components oftotal suspended particulate matter (TSP) and PM₁₀ have beenanalyzed in order to assess two distinct types of anthropogenicinput. The first of these relates to the immense reclamation andconstruction activities for new developments and airportconstruction. The concentrations of crustal components inPM₁₀ (= TSP – PM₁₀) were found to peak at the time ofthis maximum activity. A second type of anthropogenic input,ambient lead from petrol vehicles, has decreased in Hong Kongand now represents a regional background. Ambient bromine nowarises mainly from the seasalt source.     

拉萨地区夏季大气CO,SO2及NO2变化初探

为研究青藏高原大气臭氧的光化学过程及其与气溶胶的相互作用 ,1998年夏季在西藏拉萨郊区对大气CO ,SO2 及NO2 进行了综合测量。初步分析表明 ,近地层CO日平均质量分数为 14 0× 10 - 9～ 75 0× 10 - 9,夏末呈明显增高趋势 ,CO含量的日变化呈双峰型 ,清晨和傍晚较高 ,与当地人为活动排放、风向频率和大气混合层高度的日变化密切相关 ;SO2 平均质量分数为 0 15× 10 - 9,NO2 为 0 39× 10 - 9,NO2 约是SO2 的2 6倍 ,两者间存在一定的正相关 ,大致反映了该地区生物质燃料占主导的污染排放特征     

Shell colour,temperature, (micro)habitat structure and predator pressure affect the behaviour of <Emphasis Type="Italic">Cepaea nemoralis</Emphasis>

Although shell colour polymorphism of the land snail Cepaea nemoralis is a well-known phenomenon, proximate and ultimate factors driving its evolution remain uncertain. Polymorphic species show variation in behavioural responses to selective forces. Therefore, we estimated effects of various environmental factors (temperature, humidity, food availability, (micro)habitat structure and predatory pressure) on behavioural response (frequency of locomotion, climbing and hiding) of C. nemoralis morphs, in experimental and natural conditions. In the experimental part of study, the frequency of locomotion was negatively affected by temperature and the presence of food and positively influenced by the presence of light. Morphs significantly differed in behavioural responses to environmental variability. Pink mid-banded and yellow five-banded morphs climbed less often and hide in shelter more often than yellow and pink unbanded individuals when temperature was low and food was absent. Snails fed most often at moderate temperature compared to low and high temperatures. Field investigations partially confirmed differences among morphs in frequency of climbing, but not in terms of probability of hiding in sheltered sites. In natural colonies, temperature and (micro)habitat structure significantly affected frequency of climbing as well as hiding in shelter. Snails more often hid in sheltered sites where thrushes preyed on Cepaea. Tendency of unbanded morphs to climb trees may have evolved under avian predatory pressure as thrushes forage on a ground. Tendency of banded morphs to hide in sheltered sites may reflect prey preferences for cryptic background. The results implicate that differential behaviour of C. nemoralis morphs compensate for their morphological and physiological limitations of adaptation to habitat.