Cassini Growth of Population Between Two Metropolitan Cities——A Case Study of Beijing-Tianjin Region,China

The existing models of population distribution often focus on the region with a single city or even multiple centers, and lack the detailed explorations of the common and special type of urbanization areas with two centers. Taking Beijing-Tianjin region of China, which is a distinct dual-nuclei metropolitan area in the world, as an example and choosing Landsat-5 TM image in 2005, population, etc. as the data, this paper devotes to comprehending and illustrating a model of Cassini growth of population between the two metropolitan cities through the research of spatial population distribution pattern, aided with RS and GIS techniques. Main technical processes include Kriging interpolation of the population data and character simulation of the Cassini ovals. According to the calculation of a/b, a key characteristic index of Cassini growth model, the spatial structures of population distribution were given. When a/b〈 1, it is a curve with two separated loops with a population density more than 3000 persons/km^2. When a/b=1, it is a lemniscate curve with a population density about 3000 persons/km^2. When 1〈a/b〈 √2, it is a dog-bone shaped concave curve with a population density between 500-3000 persons/km^2. When a/b= √2, it is an oblate curve with a population density about 500 persons/km^2. When a/b〉 √2, there is an oval-shaped convex curve with a population density less than 500 persons/km^2. The results show that owing to the combined action and influence of the regional dual-nuclei, the population distribution of Beijing-Tianjin region is in accord with Cassini model significantly. Therefore, there is Cassini growth of population between the two metropolitan cities in Beijing-Tianjin region. In addition, the process of Cassini growth has extraordinarily instructive significance for judging the development stages of the dual-nuclei metropolitan areas.

Metropolis or City?Metropoles and Cities with Their Citizens

Through the specific examples of two very different metropoles,not compared but evoked,New York City and Bordeaux Métropole,since globalization from mid-19th and to the beginning of the 21st century,we can observe how metropolitan flows acceleration change cities and citizens heritages.How can we achieve metropolization and globalization of our cities?

Understanding the Urban Sprawl in the Mid-Size Latin American Cities through the Urban Form:Analysis of the Concepcion Metropolitan Area(Chile)

Latin American cities, like those from North America and Europe, experience problems of urban sprawl. However, few studies have dedicated exclusively to this phenomenon in specific cities, and this omission is particularly noticeable regarding cities not considered among the megalopolis of the continent. The present work analyzes urban sprawl through an urban form in the Concepción Metropolitan Area, Chile, between 1990 and 2009, considering local aspects that may have played a role in the process. The main empirical results obtained from this study reveal a metropolitan area that has expanded intensely over a 20-year period, growing from 9000 hectares to more than 17,000 ha for a 96% increment in the built-up area. The new urban surfaces consolidate a central conurbation that strengthens the role of the main downtowns, with less-intense occupation towards the sub-centers but in a structure that follows the transportation infrastructure. Over the last 20 years, the distance between the shapes has grown progressively by around 2 km, increasing the size of the ellipse by more than 1000 km2. In particular the complexity of the urbanized surfaces has grown, becoming more irregular in shape and less compact as they come to occupy larger areas. So our principal findings include: an increment of nearly 100% in the urban surface, the importance of a polycentric urban structure in the process of consolidation as a support for analyzing different spatial dynamics, and the growing morphological irregularity of the territory of the sprawl.

Perceptions on Public Health Facilities by Slum Dwellers in the Metropolitan Cities of India

Rapid urbanisation and quest for better livelihood, push-pull factor of occupations education, policy changes attract large scale rural population to urban areas. It is well documented that in spite of better public health facilities including tertiary care hospitals which are available in the urban areas but the services are underutilised by the urban poor. Aim: Hence, in this paper, it is attempted to comprehend the reasons for underutilisation of available public health facilities and to compare the difference with non-slum areas of the major metropolitan cities of India. Methods: A secondary data from National Family Health Survey-III for five major metropolitan cities namely, Delhi, Hyderabad, Mumbai, Kolkata and Chennai is used for the analysis. Slum data which are classified by both the agencies, that is census of India and NFHS-III as slum households only considered for analysis. Results: In Mumbai slums about 90% of the households are having water sources from public tap or piped to yard followed by Hyderabad having better water supply and Chennai slum dwellers having minimum access to good water sources. About 11.4% of the households do not know where their toilet drainage is connected. There is a significant (P 0.05) 75% to 79%, Kolkata and Chennai have parallel high proportion, that is more than 95% (P > 0.05) and Mumbai stands as median percent age as 89.6. Apart from Delhi, about 40% to 45% of the slum population is in the opinion of “long waiting time” in the government hospitals, and the same trend of proportions is observed for “poor quality of service”.

Molecular Diversity of the Human Immunodeficiency Virus Type 1 in Metropolitan Cities in Central Africa: An Update of Data

The Human Immunodeficiency Virus (HIV) has a diversity that is equal to the complexity of its management. The group M (Major) is the dominant group in Sub-Saharan Africa and its distribution is very heterogeneous;the diversity of the virus is more heterogeneous in this region than elsewhere in the world which follows a complex and specific algorithm because of geographical positions and countries. This distribution is very dynamic, evolving and unpredictable. This review aimed to expose the specifics of the HIV Type 1 epidemic in Central Africa, in terms of the different molecular variants of HIV published for the region compared to the geographic location. Both Type 1 and Type 2 of HIV are prevalent in sub-Saharan Africa due to distinct geographical contexts. HIV-2 is mainly documented in West and Central Africa, particularly in Cameroon, Guinea-Bissau, Gambia, Senegal, Ivory Coast and Burkina-Faso however HIV-1 infection is widely distributed across the continent. The HIV-1 epidemic in Sub-Saharan Africa is dominated by the Group M. The different subtypes respect a certain geographical distribution across the continent. West Africa is dominated by subtype A, East and South Africa are dominated by subtype C, while Central Africa is dominated by strains A, C, D, F, H, J, CRF01-AE and CRF02-AG. This review is the first to present de molecular diversity of HIV-1 in metropolitan cities in all central African countries. The Circulating Recombinant Form (CRF02_AG) and subtypes A and G are present in all Central African countries and are also the most commonly encountered;followed by the subtypes D, F, G, C, B, J, K and several Circulating Recombinant Forms that are not represented in all Central African countries.

宁波都市区城市群的生态环境问题与森林应对策略

2021年中欧双方联合开展了中欧绿色城镇化的城市森林应对关键技术研究项目,我国宁波都市区是长三角区域内的重要发展极核之一,其城市群建设也是该研究项目的典型案例。文章在总结宁波都市区“小城镇点状发展-大都市主导发展-城镇化高速发展”的发展历程的基础上,从区域尺度综合分析城市组团之间生态空间、森林质量与景观风貌、外来入侵植物、河流水系生态廊道、城乡居民生态福祉、平原村庄风貌等9个方面的生态环境问题,最后提出群域区生态共建共享共治、中心区生态空间查漏补缺、核心区生态服务能力提升和绿水青山变金山银山挖潜4方面的森林应对策略,以推进长三角区域生态协同、助力美丽杭州湾建设、构建宁波都市区生态安全共同体。

深化沈阳现代化都市圈一体化发展的挑战与对策

现代化都市圈一体化发展是城市和国家经济发展到一定阶段的必经之路,本文采用定量和定性分析相结合的方法,深入分析沈阳现代化都市圈一体化发展过程中面临着产业发展阶段存在差异、产业结构趋同、深层次产业分工协作较弱等问题,并根据沈阳都市圈7市1区的实际状况,提出构建“1+ 2+ 6”式对策机制,围绕政务一体化、交通一体化和现代化、基础设施一体化、数字资源一体化、产业一体化和互补共生化、公共服务一体化和便利化等方面建立城市跨界发展与互通模式,重塑以沈阳为中心的辽宁经济发展格局,加快辽宁和东北经济发展。

襄阳都市圈旅游一体化发展路径研究

中国式现代化和新发展格局对区域旅游一体化提出了新的要求。旅游一体化是城市一体化的重要组成部分,襄阳都市圈旅游一体化发展问题要立足汉江流域、南襄盆地、中西部新通道的大格局来分析,最为关键的就是“襄十随神”城市群旅游一体化。襄阳都市圈各城市地域相接、交通相连、文脉相通,共饮一江汉水,旅游一体化基础良好。围绕五大主题游线,重点做好增加旅游一体化合作收益、拓展襄阳旅游中心城市功能、谋划城市群旅游新格局、丰富城市群旅游形象和业态等方面的工作。

都市圈发展与新城建设中的城市交通机遇与挑战——中国城市交通发展论坛第36次研讨会

打造更高质量、更具竞争力的大都市圈,是国内外城市区域化发展的共同战略。新城的建设和发展成为都市圈治理的产物,是完善城镇化发展战略的重要决策,是落实城市总体规划、提升城市功能、优化发展布局的必然要求。中国城市交通发展论坛于2024年5月23日在上海市举办了2024年第2次(总第36次)常规研讨会,主题为“都市圈发展与新城建设中的城市交通机遇与挑战”。与会嘉宾围绕如何满足都市圈通勤交通功能、控制城市交通极端通勤、都市圈一体化发展中高快速路与市域(郊)铁路的功能定位与协同、节点型新城综合交通体系构建的难点与特殊性、新城发展如何应对都市圈交通与本地交通的空间及功能叠合等议题展开研讨。本次论坛由中国城市交通发展论坛组委会主办,同济大学城市交通研究院、上海市城市规划设计研究院、上海市城乡建设和交通发展研究院、上海市城市建设设计研究总院(集团)有限公司联合承办。

厦漳泉都市圈跨城通勤特征及其影响因素——以角美镇跨城通勤者为例

以厦漳泉都市圈的角美镇台商投资区为例,基于问卷调查和深入访谈获得的数据和资料,对比分析通勤者的群体特征、通勤模式和通勤路径,构建框架解释角美镇跨城通勤的形成机制,最后探析其对海峡两岸融合发展的影响。研究发现:与一般通勤者相比,跨城通勤者群体具有高学历、高收入、社会经验丰富,以及通勤时间和通勤花费都略高的特征;通勤方式以机动车出行、公共交通出行、组合出行方式为主,通勤路径主要有漳州—厦门和厦门—漳州两类;跨城通勤行为的产生是两地间的产业转移与承接,住房、公共服务、交通设施的差异与互补,以及相同的语言风俗文化共同作用的产物;案例地跨城通勤的发展壮大对建立海峡两岸产业发展示范园起到一定的促进作用。

福州都市圈市域铁路网络架构研究

[目的]为应对福州都市圈的发展要求,需构建与其他轨道交通方式高效融合的市域(郊)铁路网,大幅提升福州市中心城区与外围组团、临近郊县之间的空间效应,缩短福州都市圈内交通出行时间,满足福州都市圈主圈层1 h通勤圈的交通需求。[方法]在阐述福州都市圈社会经济及轨道交通概况的基础上,参考国内外都市圈的发展经验,对福州都市圈圈层尺度进行识别,将福州都市圈分为1个主圈层(含交通半径为40 km的通勤圈、交通半径为70 km的辐射圈)和4个次圈层。采用以“功能层次法”为基础、以“节点锚固法”+“点线面法”为支撑的技术方法,提出了福州都市圈主圈层市域铁路网络规划方案,并对该方案进行了效果评价。[结果及结论]该方案对促进福州都市圈内新型城镇化建设、拓宽中心城市发展空间、扩大城市轨道交通辐射半径、提高福州都市圈1 h通勤圈协同发展水平均具有重要的支撑意义。

中国式现代化背景下省会城市发展新论

中国27个省区都形成了以省会城市为中心的都市圈,对推进人口规模巨大、全体人民迈向共同富裕的中国式现代化建设,具有重要的战略支撑作用。从省会城市承担的区域功能看,以提升城市能级为导向实施强省会战略,强省会才能强都市圈,省会城市应以提升能级为导向,加快推进高质量发展。展望以提升城市能级为导向实施强省会战略,要提升省会城市能级推进人口规模巨大的中国式现代化,提升省会城市能级推进迈向共同富裕的中国式现代化,提升省会城市能级推进物质文明和精神文明相协调的中国式现代化,提升省会城市能级推进人与自然和谐共生的中国式现代化,提升省会城市能级推进迈向国际化的中国式现代化。

南京都市圈跨市日常人口流动影响因素及其空间效应研究

跨市日常人口流动逐渐成为衡量都市圈一体化水平的重要因素,其不仅受到本地社会经济环境的影响,也受到邻近地区发展的空间效应影响,但目前对其影响因素及空间效应的讨论相对较少。因此,文章对其影响因素及其空间效应进行研究。研究发现:①南京都市圈跨市日常人口流动规模和节点控制力分别形成了以南京市为核心向外围扩散和以边界区域为核心沿主要交通走廊分布的空间格局。②其分布具有空间依赖性,流动规模主要体现在周边区域对空间单元的随机冲击,节点控制力主要体现在周边区域中介作用提升对本区域的空间溢出作用。③影响其空间格局的因素较为复杂,流动规模受到公服设施、交通建设、经济社会属性多种类型的因素影响,而节点控制力则主要与公服设施、交通建设相关。研究进一步丰富了日常人口流动的研究内容,既从空间效应维度对其形成机制进行补充,也为跨区域人口流动引导体系的构建提供了依据。

大都市区周边乡村风貌提升管控研究——以上海市4个乡村振兴示范村为例

上海作为国际化大都市区,城市功能不断提升的同时,周边乡村风貌也亟需建设与发展。本文基于庄行郊野公园、海星村、塘湾村和聚源桥村等具体实践,从乡村风貌提升的背景及面临的问题、乡村风貌提升管控的重要作用、大都市区乡村风貌管控的价值认知及乡村风貌提升管控策略和路径等几个方面着手展开深入探索,归纳提炼出大都市区周边乡村风貌五大核心提升管控要素:乡村道路修复、重点界面重塑、公服区域复合、驻留节点构建、导视标志植入。以风貌要素为依托,构建立足此时此地的大都市区周边乡村风貌分级管控标准,并对乡村风貌规划设计提出具体实施策略,以期为上海市周边乡村风貌提升管控提供参考借鉴。

基于核心城市带动力的广东省五大都市圈高质量发展策略研究

建构都市圈高质量发展、核心城市带动力两套测度体系,运用灰色关联分析方法,探讨广东省五大都市圈发展核心问题、五个核心城市带动力差异及其对都市圈高质量发展的影响机制。结果表明:(1)根据五大都市圈及其核心城市带动力水平,深圳都市圈为总体高质型,广州、珠西都市圈为重点提质型,汕潮揭、湛茂都市圈为全面提升型;(2)核心与非核心城市间生态联系、非核心城市产业转移承接力、核心城市经济辐射力是都市圈高质量发展的重要影响因素;(3)都市圈不同维度高质量发展水平影响因素各异,其中经济辐射力具有共性影响作用。进而提出五大都市圈高质量发展的差异化提升策略。

大都市近郊地区国土空间规划技术框架--以成都市郫都区为例

在国家推动城乡融合、促进乡村振兴与超大特大城市转型发展的时代背景下,大都市近郊地区成为探索城乡融合发展路径的前沿阵地。以成都市郫都区为研究对象展开分析,针对其面临的现状生活服务设施难以匹配人群多元化的需求、生产空间难以支撑新业态转型发展、土地破碎难以满足高品质环境需求等问题,提出规划应对策略:完善城乡居住网络、服务体系,促进生活融合;健全产业生态、优化空间布局,推动产业建圈强链,促进生产融合;构建城乡公园体系、整合空间管控,促进生态融合;完善规划传导体系、政策体系、标准体系,保障规划落地。

Stable Isotopic Signatures of NO3 in Waste Water Effluent and Los Angeles River

A metropolitan city such as Los Angeles (LA) is an ideal study site with a very high population density, and it houses at least 3 treatment plants where sewage is treated preliminarily and then progressing to tertiary treatment before discharging into the LA River. We will gain a better understanding of the water quality in the LA River and the nitrate load in the watershed system by examining the influence of waste water treatment plants (WWTPs). The goal of this study is to pinpoint the exact source of nitrate in the LA River using the isotope signatures. We have selected sampling locations both upstream and downstream of the WWTP. This serves to monitor nitrate levels, aiding in the assessment of treatment plant effectiveness, pinpointing nitrate pollution sources, and ensuring compliance with environmental regulations. The research explores the isotopic composition of NO3 in relation to atmospheric nitrogen and Vienna Standard Mean Ocean Water, shedding light on the contributions from various sources such as manure, sewage, soil organic nitrogen, and nitrogen fertilizers. Specifically, there is a change in the δ15NAir value between the dry and wet seasons. The isotope values in the Tillman WWTP sample changed between dry and wet seasons. Notably, the presence of nitrate originating from manure and sewage is consistent across seasons, emphasizing the significant impact of anthropogenic and agricultural activities on water quality. This investigation contributes to the broader understanding of nitrogen cycling in urban water bodies, particularly in the context of wastewater effluent discharge. The findings hold implications for water quality management and highlight the need for targeted interventions to mitigate the impact of nitrogen-containing compounds on aquatic ecosystems. Overall, the study provides a valuable framework for future research and environmental stewardship efforts aimed at preserving the health and sustainability of urban water resources. This data informs decisions regarding additional treatment or mitigation actions to safeguard downstream water quality and ecosystem health.

多圈层视角下北京市轨道交通发展策略研究——基于与东京都市圈的对比分析

为更好支撑新发展阶段下北京市轨道交通的规划建设,以东京都市圈与北京市的轨道交通线网为研究对象,在多尺度分析和总结东京都市圈轨道交通发展经验的基础上,梳理东京都市圈和北京市在8 km以内、8~15km、15~30km、30~50km和50km以外5个圈层的轨道交通线网规模及不同圈层的轨道交通服务水平,形成相关量化指标,并通过指标对比,总结东京都市圈和北京市不同圈层轨道交通的特征差异,最后以此为据提出北京市未来的轨道交通发展建议,以期推动北京市轨道交通高质量、可持续发展。

跨界共生:深圳都市圈跨界地区枢纽集群协同发展态势研究

随着都市圈快速发展,跨界地区不再是发展边缘地带,逐渐成为区域发展的重要平台。深圳都市圈临深的跨界地区,形成了产业外溢、人口外迁的城镇带。在此背景下,跨界地区裂变成为多个功能组团,跨界地区枢纽也在增密布设。将跨界地区与跨界枢纽相结合,通过对跨界枢纽群地区从枢纽可达性、中心契合性、企业集聚性、功能协调性、枢纽协同性5个维度进行创新性评估,探究当前跨界地区与跨界枢纽群发展特征及存在的问题。通过评估分析发现,跨界地区融合性发展需求高、资源禀赋较好、差异类型多,但行政边界与自然边界对融合发展阻碍仍较大,部分地区“有城无站”,部分地区“有站无城”,站城融合发展、城镇带与枢纽集群耦合发展尚待进一步优化。其中,枢纽级别提升与站外空间产业布局需要根据地区发展做出调整,跨界地区新城选址与功能节点要结合枢纽布置,形成完整发展单元,促进都市圈功能网络可持续发展。

上海职住关系与城市通勤问题空间治理策略

职住空间不平衡是城市通勤时间增加的重要原因。在上海城市去中心化的过程中,就业中心和居住中心的空间错配造成了大量的长距离通勤,对上海交通形成巨大压力,并影响居民幸福感。因此,在大都市交通治理中,推动上海“五个新城”体系打造,因地制宜地突出“五个新城”规划特色,构建多节点、多中心的通勤网络,同时加强保障房政策实施,提高新城和郊区公共服务的均等化水平,能够有效地促进职住平衡,推动城市可持续发展。