Dislocating modernity: Identity, space and representations of street trade in Durban, South Africa

South Africa’s cities have experienced dramatic changes over the past decade. Cities are now home to a multiracial population, and have been transformed by new forms of economic and social interaction. For some, these changes have become a significant source of fear and anxiety. In this paper, we examine reactions to urban spatial change in the city of Durban, as expressed in local newspapers and interviews with suburban residents. We describe how the discourses of urban change in Durban have centred on the increased presence of street traders within the city’s public spaces, and the various ways in which the activity of street trade has disrupted long-established modernist norms governing the occupation and use of the urban space. Specifically, we offer a detailed reading of three prominent narratives within the discussion of street traders in Durban--chaos, congestion and pollution. We argue that street traders have come to embody a wide range of more deeply seated cultural anxieties, which have been brought to the fore in the context of South Africa’s transition. These anxieties arise from the ways in which modern understandings of order, agency and subjectivity have been called into question by material changes in the city, and have implications for the nature of citizenship and civic engagement in post-apartheid South Africa.     

Responsible adults-in-the-making: Intergenerational impact of parental migration on Indonesian young women’s aspirational capacity

In the developing economies in Southeast Asia, labour migration is increasingly seen not simply to generate income to meet short-term livelihood needs but to secure the family’s future, often by investing in children’s education. While much work has been done studying the impact of parents’ remittances on children’s wellbeing including education access, the impact of parental migration on children’s (educational) aspirations has received less attention. Viewing youth as social actors, this paper interrogates how they make meaning of their parents’ migration, and how this consequently influences their decisions to activate, delay or reshape their hopes and plans for their own educational and work trajectories. With the increasing feminisation of labour migration in Southeast Asia where gendered regimes in care and domestic work make it easier for women to work overseas, this paper focuses attention on the aspirations of young women at the cusp of adulthood from a migrant-sending area in rural East Java, Indonesia. These young women’s ‘navigational capacity’ (Appadurai, 2004) is not only shaped by tangible obstacles such as the lack of sufficient resources, but is also more subtly moulded by an emerging discourse of self-responsibilisation in the making of ‘dutiful daughters’. Drawing on conceptualisations of multiple ‘logics of aspiring’ operating within spatial contexts (Zipin et al., 2015), we show how young women unsettle, inflect and challenge the normative linear education-work transitions by expressing their desire to replace their parents in accessing labour migration as a livelihood option, and reflect on the dialectical relationship between agency and aspirations.     

Navigating the terrains of transnational education: Children of Chinese ‘study mothers’ in Singapore

This paper demonstrates the value of child-centred migration studies which highlight children’s role in shaping the migration journeys of their families, as well as their own projected journeyings. It examines the case of children from China who move to Singapore, an aspiring global education hub, expressly for the purpose of an overseas education that will facilitate longer-term migration and life goals. Focus is given specifically to the children of ‘study mothers’ or peidu mama (literally: ‘mothers accompanying their children who are studying’). Through interviews with the teenagers and the conceptual optic of ‘social navigation’, our paper demonstrates that children are resilient and creative beings able to navigate the twists and turns of their immediate trajectories, as well as develop their own goals and projected destinations for their futures. The paper calls for a refinement in the way we understand children’s mobilities. First, in arguing that their spatial journeying across the terrains of transnational education cannot be decoupled from their process of social becoming and emotional development from passive followers to active negotiators, we wish to disrupt hegemonic discourses and dominant representations of children in migration as simply ‘migrant’s children’ and restore them to the status of ‘migrant children’. Second, adopting the concept of social navigation as an analytical lens allows us to highlight the fluid ways that young people think about their futures and the different pathways by which they can get there. This leads us to conceive of social and cultural capital accumulation through transnational education as a process with many more degrees of provisionality than what is often presented in the literature as a ‘strategic project’ with a fixed and abstract goal.     

Comparative zinc dynamics in Atlanta metropolitan region stream and street runoff

Zinc, major ion, and other trace metal (V, Cr, Co, Ni, Cu, Cd, and Pb) concentrations were measured within 172 street and stream runoff samples in the Atlanta metropolitan region and in relatively undeveloped watersheds within the Georgia Piedmont and Blue Ridge Provinces. Peachtree Creek, draining a densely populated area of Atlanta, was the primary sampling location and samples were acquired under a wide range of hydrological conditions. Zinc concentrations within street runoff [median (Zn)_{urban street runoff}=905 µg/l] were significantly greater than zinc concentrations within storm runoff [median (Zn)_{Peachtree Creek}=60 µg/l], which were, in turn, greater than zinc concentrations within non-storm runoff [median (Zn)_{Peachtree Creek}=14 µg/l]. Zinc concentrations were not significantly greater within urban base flow than within non-urban base flow, indicating that the primary source of pollution is "event water" or street runoff. Zinc was the only heavy metal present in greater than "background" concentrations (i.e., >10 µg/l), which is likely the result of automotive pollution that is omnipresent within the study area. Analysis of storm alkalinity dilution trends indicate that simple mixing between polluted street runoff and groundwater cannot account for the zinc concentrations observed within storm and recession flows. A two end member mass balance model suggests that a large proportion of the zinc present in the street runoff is adsorbed and transported on surfaces of the suspended sediment. Adsorption is readily possible at the near neutral pH (~6.5) of turbid storm discharge.     

Heavy metal contamination of urban soils and street dusts in Hong Kong

Due to rapid urbanisation and scarcity of land, most of the urban parks and recreational areas in Hong Kong are built close to major roads or industrial areas, where they are subject to many potential pollution sources, including vehicle exhaust and industrial emissions. An extensive soil survey was conducted in urban parks of Hong Kong to study the current conditions of heavy metals contamination in soils. Soil samples and associated street dusts were collected from more than 60 parks and public amenity areas in old urban districts, industrial areas and New Towns of the territory. Soils were also sampled in the remote country parks to establish the baseline conditions. The total concentrations of heavy metals and major elements in the samples were determined. The results indicate that urban soils in Hong Kong have elevated concentrations of Cd, Cu, Pb and Zn. The parks with high metal concentrations are located in old urban commercial districts and industrial areas, indicating that the major contamination sources in these soils are traffic emissions and industrial activities. In addition, the application of Cd containing phosphate fertilizers may be an important source of Cd in urban park soils. The street dusts have highly elevated Zn concentration, particularly along the main trunk roads. The high Zn content in the street dusts may come from traffic sources, especially vehicle tyres. Selective soil and road dust samples were also analysed for potential chemical speciation by a sequential chemical extraction method. The chemical partitioning results show that Pb and Zn are mainly in the carbonate/adsorbed and Fe–Mn oxide phases, while Cu is largely associated with the organic and sulphide fractions. The high exchangeable Cd in urban soils and high concentration of Zn in street dusts need further investigation for their ecological and health implications.     

The spatial characteristics and pollution levels of metals in urban street dust of Beijing,China

The components and concentrations of metals in street dust are indictors of environmental pollution. To explore the pollution levels of Cd, Cr, Cu, Mn, Ni and Pb in street dust and their spatial distribution characteristics, 220 dust samples were collected in a grid pattern from urban street surfaces in Beijing. Multivariate statistics and spatial analyses were adopted to investigate the associations between metals and to identify their pollution patterns. In comparison with the soil background values, elevated metal concentrations were found, except those for Mn and Ni. The results of the geo-accumulation index (I_geo) and the potential ecological risk index (Erⁱ) of the metals revealed the following orders: Cd > Cu > Cr > Pb > Ni > Mn and Cd > Cu > Pb > Cr > Ni. Levels of I_geo ranging from 0 to 5 were found and about 80% of the samples were below the moderately polluted level. The Erⁱ values of single elements were within the low ecological risk level in most sampling sites. Most of the metals in the street dust of Beijing were statistically significantly correlated. It is hard to clearly identify the sources of each metal in the street dust since local environments are very complex. Cadmium, Cu, Cr, Mn and Pb showed medium spatial autocorrelations within the sampling region. Similar spatial distribution patterns were observed for Cu, Cr and Pb, and these metals had relatively high spatial variabilities and were enriched in the center of the city with several peaks scattered in the suburbs. Metal pollution anomalies were identified by using cluster and outlier analyses. Locations identified as clusters with high values indicated non-point source pollution, while locations identified as outliers with high values indicated point source pollution. Traffic, construction, and other human activities influenced these high values. In addition, the locations identified as outliers with low values in urban areas might benefit from less transportation and better management.     

Assessment of heavy metal contamination levels of street dust in the city of Lublin,E Poland

Heavy metals are constantly emitted into the environment and pose a major threat to human health, particularly in urban areas. The threat is linked to the presence of Cd, Cr, Cu, Ni, Pb, and Zn in street dust, which consists of mineral and organic particles originating from the soil, industrial emitters, motor vehicles, and fuel consumption. The study objective was to determine the level of street dust contamination with trace metals in Lublin and to indicate their potential sources of origin. The analyses were carried out with an energy-dispersive X-ray fluorescence spectrometer. The sampling sites (49) were located within the city streets characterised by varying intensity of motor traffic. The following mean content values and their variation (SD) were determined: Cd: 5.1?±?1.7 mg kg^?1, Cr: 86.4?±?23.3 mg kg^?1, Cu: 81.6?±?69.2 mg kg^?1, Ni: 16.5?±?3.9 mg kg^?1, Pb: 44.1?±?16.4 mg kg^?1, and Zn: 241.1?±?94.6 mg kg^?1. The level of pollution was assessed with several widely used geochemical indices (geoaccumulation index, enrichment factor, pollution index, index of ecological risk, and potential ecological risk index). For most of the indices, the mean (median) values are arranged in the following manner: Zn?>?Cu(or Cd)?>?Pb?>?Ni?>?Cr. In general, street dust in Lublin does not show pollution with Cr, Ni, and Pb. I_geo and EF indices show moderate levels for Cu, Cd, and Zn; their presence in street dust is linked with anthropogenic factors (motor traffic). A significant threat is posed by Cd, and more than half of the samples show considerable pollution with cadmium (median for the index of ecological risk: 151). The spatial pattern of indices and the results of statistical analyses (CA, PCA) indicate three groups of elements: (1) Cr and Ni: natural origin; (2) Pb: mixed origin; and (3) Cd, Cu, and Zn: anthropogenic origin (mainly motor vehicle traffic). Higher content values for metals of anthropogenic origin in street dust indicate that it is a source of pollution of soil and air in the city.     

LiDAR-based three-dimensional street landscape indices for urban habitability

Streets are like the skeleton of a city. They not only guarantee urban traffic functions and facilitate business activities, but also perform an integral component of the urban landscape. Urban habitability, that is to judge whether a place is suitable for people to live, has been a popular topic for years. A mobile laser scanning (MLS) system can obtain close-range three-dimensional (3D) light detection and ranging (LiDAR) data of the sides and surfaces of urban streets. This study explored the possibility of analyzing urban street space landscapes based on MLS LiDAR, and proposed four LiDAR-based 3D street landscape indices for urban habitability: 3D green biomass, street enclosure, sunshine index, and landscape diversity index. Experiments performed in Jianye District of Nanjing (China) showed that these four street landscape indices accorded well with the actual situation and they reflected user perception of street space. Thus, the proposed indices could help us to assess urban landscape from a 3D perspective. To sum up, this study suggest a new type of data for landscape study, and provide an automatic information acquirement for urban habitability assessment.     

Amenity migration to the global south: Implications for community development

Despite a growing trend of migration to countries in the global South fueled by their natural amenities (i.e., natural amenity migration), research on this topic has predominantly been conducted in the global North. This is problematic given the notable socioeconomic, attitudinal, and behavioral differences between amenity migrants (often urbanites from developed countries) and local people (often rural residents of developing countries). Grounded in community field theory, this study begins to fill this gap in the literature by increasing our understanding of the ways in which local residents and amenity migrants interact in the amenity-rich community of Nuevo Arenal, Costa Rica. We found that linguistic, cultural, and spatial barriers (real and perceived) created a social climate in which the interaction between local residents and amenity migrants was primarily based on mundane interactions and did not lead to social integration. This proved to be a hindrance to the creation of the community field, which led to a lack of joint planning and participation in activities and projects that sought to improve the overall living conditions in the community. Explanations of these findings and the implications of such a divide are offered.     

Imagining migration: Placing children’s understanding of ‘moving house’ in Malawi and Lesotho

Research pertaining to children’s geographies has mainly focused on children’s physical experiences of space, with their ‘imagined geographies’ receiving far less attention. The few studies of children’s imagined geographies that exist tend to focus on children’s national identities and their understanding of distant places. However, children’s lives are not necessarily static and they often move between places. Research has not so far considered children’s images of these transitional spaces or how such images are constructed.Through an examination of over 800 thematic drawings and stories, regarding ‘moving house’, produced by children aged 10-17 years in urban and rural communities of Lesotho and Malawi, this paper explores southern African children’s representations of migration. The research considers how ideas of migration are culturally-constructed based on notions of family, home and kinship, particularly in relation to the fluid family structure characteristic of most southern African societies. The results suggest that most children imagine migration as a household rather than an individual process, rarely including micro-migrations between extended family households in their drawings. Further, children’s images of migration are place-rooted in everyday life experiences. Their representations concentrate on the reasons for migration, both negative and positive, which are specifically related to their local social and environmental situations and whether house moves take place locally or over longer distances. The paper concludes by exploring the implications of these conceptualisations of moving house for children’s contemporary migration experiences, particularly in light of changing family structures due to the effects of the HIV/AIDS pandemic.     

Inter-metropolitan migration of the newly landed immigrants in Canada: 1991–1996 and 1996–2001

Based on the tabulations of the Longitudinal Immigration Data Base, I characterized, explained and compared the 1991–1996 and 1996–2001 inter-metropolitan migration of the newly landed immigrants in Canada. The spatial and temporal patterns were consistent with the neoclassical economic theory and the ethnic enclave theory. In making their decisions on departure and destination choices, the immigrants were responsive to income and employment incentives, as well as the retaining and attracting powers of ethnic communities among Census Metropolitan Areas (CMAs). The research also discovered an interesting temporal pattern—while the inter-CMA migration of immigrants accentuated the over representation of the immigrants in Toronto and Vancouver in the 1991–1996 period, the rise of the “secondary” CMAs led to a spatial dispersal of the immigrants in the 1996–2001 period. This finding supplements the existing literature on internal migration of Canadian immigrants, which discovered little evidence of an increased dispersion of immigrants over time.     

Escape to victory: Development,youth entrepreneurship and the migration of Ghanaian footballers

This article contributes to contemporary debates over the resourcefulness and entrepreneurialism of young people in the Global South by exploring the relationship between development and the migration of male youth within the football industry. Drawing on fieldwork in Accra, the paper reveals how young Ghanaians attempt to enact development as freedom through spatial mobility. Significantly, this is coupled with an awareness that their desired spatial mobility is difficult to attain, thereby inducing a sense of involuntary immobility. For some male youth, the solution to this predicament is to invest in their sporting bodily capital and become Foucauldian ‘entrepreneurs of self’ in the form of a professional footballer. Meanwhile for others, the solution to prevailing economic pressures is to embrace financial risk by becoming entrepreneurs in the form of football club owners, and attempting to profit from the movement of players. The interests of these two sets of entrepreneurs coalesce around the fact that the mobility of footballers is crucial to generating a return on their respective investments. It is argued that the construction of young Ghanaians as responsible for their future life chances, and the growing dissonance between aspirations and the ability to migrate, is a key reason why youth are trying to migrate through football. Problematically, this can foster conditions favourable for irregular migration.     

城市洪涝中雨水口泄流能力的试验研究

近年来中国城市洪涝灾害频发,对人民群众的生命财产安全造成了严重威胁,其中雨水口泄流能力的大小对于计算受淹区的积水程度或路面雨水的排除效率至关重要。为此本研究专门修建了具有上下两层结构的城市洪涝过程综合试验平台,考虑雨篦子、雨水井及侧支管等完整的雨水口结构,开展了76组不同来流水深及流速下的雨水口泄流能力试验。试验结果表明:雨水口的下泄流量在井身充满前后表现出不同的变化规律,即在雨水井充满前,路面雨水以堰流形式下泄;在雨水井充满后,以管嘴出流形式下泄。基于试验数据率定出雨水口堰流及管嘴出流时的流量系数,并进一步采用量纲分析法,建立雨水口的泄流能力与雨篦子尺寸、篦前水流的弗劳德数等因素之间的经验关系,具有较高的相关系数。采用本文公式计算原型尺寸雨水口的泄流能力,并与中国现行雨水口泄流能力的参考值进行对比,发现当水深较大时现行参考值偏大较多。本研究成果能为精细化的城市洪涝管理提供计算依据。     

Three-dimensional numerical simulations of the Downie Slide to test the influence of shear surface geometry and heterogeneous shear zone stiffness

Massive slow-moving landslides often exhibit deformation patterns which vary spatially across the landslide mass and temporally with changing boundary conditions. Understanding the parameters controlling this behaviour, such as heterogeneous material properties, complex landslide geometry and the distribution of groundwater, is fundamental when making informed design and hazard management decisions. This paper demonstrates that significant improvements to the geomechanical analysis of massive landslides can be achieved through rigorous, three-dimensional numerical modelling. Simulations of the Downie Slide incorporate complex shear zone geometries, multiple water tables and spatial variation of shear zone stiffness parameters to adequately reproduce real slope behaviour observed through an ongoing site monitoring program. These three-dimensional models are not hindered by shortfalls typically associated with two-dimensional analysis, for example the ability to accommodate lateral migration of material, and they out-perform more simplified three-dimensional models where bowl-shaped shear geometries are incapable of reasonably reproducing observed deformation patterns.     

Skilled migration in global cities from `Other' perspectives: British Arabs, identity politics, and local embededdness

Migration scholars increasingly have turned their attention to skilled migration, focusing, in particular, on the transfer of professionals within and between transnational corporations. Recent efforts have been made to bring a `cultural' analysis to this phenomenon, including greater scrutiny of the corporate cultures and social networks in which skilled migrants are embedded. This research has emphasised the importance of locality even among these most footloose and transnational of migrants. But despite these complex views of skilled migration, analyses have generated a somewhat limited conception of `skilled migrants' as managerial elites disengaged from local life. This paper examines skilled migration from a different perspective. First, using the case of Arab immigrants in London, this paper highlights the complicated nature of migration trajectories and reveals the diversity of patterns and experiences within the category of skilled migrant. Second, focusing on responses from female study participants, this paper examines the ways in which skilled migrants, rather than disengaging themselves from the host society context, may participate in the local politics of multiculturalism and integration.     

裂隙宽度空间变异性和泄漏条件对网络裂隙中DNAPLs运移影响研究

DNAPLs本身的化学性质、裂隙的几何性质以及泄漏条件等影响重非水相流体（DNAPLs）在裂隙介质中的运移和分布。针对DNAPLs的运移规律研究多集中在孔隙介质和单裂隙中,在随机网络裂隙中的研究较少。本研究生成随机网络裂隙是基于蒙特卡罗方法,运用像素扫描识别并输出裂隙的坐标和宽度,然后采用PetraSim模拟四氯乙烯(PCE)在随机网络裂隙中的运移,探讨裂隙宽度空间变异性和泄漏条件（包括泄漏速率和泄漏位置）对DNAPLs运移的影响。数值模拟结果表明:DNAPLs的空间展布和运移路径受裂隙宽度空间变异性影响,随着网络裂隙中裂隙宽度空间变异性增大,出现优势通道,DNAPLs运移的速率加快,DNAPLs的质心位置和饱和度空间分布发生明显变化;DNAPLs的运移速率和空间展布受泄漏速率影响,泄漏速率越大,DNAPLs运移速率越快,模型底部蓄积的DNAPLs的饱和度越大,DNAPLs的空间展布也越大;同一网络裂隙中,泄漏位置不同,导致DNAPLs的运移路径及分布范围不同,不同的泄漏位置重力方向裂隙空间变异性不同,导致DNAPLs运移路径和空间展布各不相同。研究结果可以丰富裂隙介质中DNAPLs运移机理研究,为裂隙介质中DNAPLs污染修复提供模型参考。     

The struggles for survival of street traders in Umtata,Transkei, 1980–89

Within the broad theoretical context provided by debates on the subordination of the informal sector to capital, the paper investigates the struggles between communities of street traders and the municipal authorities of Umtata, capital city of Transkei. The study spans the period 1980–89. Themes of concern in the paper are objections to street traders and the adoption of repressive policies towards them, the resistance of street traders and the changing attitudes of the Transkei government and Umtata local authorities towards the operations of hawkers.     

Policy responses to informality in urban Africa: the example of Maputo,Mozambique

In the global South informality constitutes one of the leading issues for urban policy makers. The planning challenges around informality are particularly relevant in urban Africa as most Africans make their livelihoods in the informal economy. This paper examines issues of state policy responses to informality through the lens of street traders. Under scrutiny are policy responses towards street trading in Mozambique’s capital, Maputo, a city that has experienced the advance of informalization. It is argued that the dominant approach towards informal trading across urban Africa is of a ‘sanitising’ policy response by the local state which is rooted upon traditions of modernist urban planning in search of ‘ordered development’. The research discloses that in Maputo national and municipal authorities have adopted a more tolerant approach to the informal economy, mainly because it provides a livelihood to so many of the city’s poor and because of potential social unrest likely to be triggered by a repressive approach. In Maputo the core narrative is of an urban informal economy viewed by officials as an important livelihood for the city’s poor, albeit one which is subject both to periodic harassment and encouragement to ‘formalize’. The analysis represents a contribution to the expanding corpus of writings on Africa’s informalising cities and specifically concerning policy responses towards street trading.     

Multivariate analysis of heavy metal pollution in street dusts of Xianyang city, NW China

Urban street dust is one of important indicators of the status of urban environmental pollution. There are many studies in capital cities, but little attention has been paid to this kind of study in medium cities, especially in China. The dust samples were collected in the district of traffic crossroads in Xianyang city, Shaanxi Province. Pb, Cd, Cu, Ni, Zn, Cr and Mn concentrations were determined by using atomic absorption spectrometry. The results indicate that street dusts in Xianyang city have elevated metal concentrations as a whole in comparison with Shaanxi Province soil, except for Mn. The content of heavy metals was comparable to those in capital cities. Correlation coefficient analysis, principal component analysis and cluster analysis were used and three main sources were identified; Mn comes mainly from soil sources; Cu, Zn and Ni are mainly derived from industrial sources combined with traffic sources; Pb, Cr and Cd have traffic sources. Heavy metal enrichment factors were calculated, which can reflect human influence degree of street dusts.     

海岸沙坝横向迁移研究综述

沙坝是波浪作用下砂质海岸地貌的主要表现形态之一,对于海滩的动力稳定状态具有重要的指示意义。从沙坝的形态参数、沙坝形成理论、沙坝迁移的动力机制以及数值模拟方法等方面概述了水下沙坝横向迁移的研究进展和存在的不足。虽然国内外学者对沙坝横向迁移进行了大量研究,然而由于海滩复杂的动力过程以及沙坝迁移与泥沙输运之间的耦合作用,目前仍存在许多问题尚待解决,未来进一步研究的方向主要包括沙坝迁移过程的空间差异、沙坝迁移的临界条件、波浪破碎对近底泥沙运动和沙坝迁移的影响、数学模型的改进以及沙坝迁移与泥沙输运的耦合机制等方面。