A GIS for environmental assessment of air pollution impacts on urban clusters and natural landscape at Rosetta City and region,Egypt

An air pollution problem is taking place in the Rosetta region resulting from the brick industry. Polluting point sources cause plumes that disperse by the prevailing wind, covering urban areas of Rosetta City and surrounding landscape of agricultural fields. A model for pollutants plumes was designed through a GIS to calculate the dispersal of total suspended particulate (TSP) loads over the landscape and to estimate its spatial distribution and to analyze its relationship with other geographic land use attributes.TSP pollutant concentrations starting from 100 g/m³ cover more than 34 km² of sensitive land cover through all the year. A concentration level of 100 g/m³ affects about 93% of the sensitive palm trees cultivation, 47% of cultivated land, and 92% of urban areas. TSP concentration level of 200 g/m³ was found to be affecting the same percentage of built-up urban areas.Concentration levels exceed the permissible limits mentioned in the Egyptian law of environment (90 g/m³). The situation is hygienically deteriorated, and large areas of agricultural land are strongly affected or subjected to future impact. Recommended measures are mostly involved with transferring this industrial activity to a safer location at the southwest of the city. The study proposes that brick mills sites on the river Nile bank be utilized for urban development projects and for the promotion of tourism.     

Energy balance and transpiration in an urban tree hedgerow in Mexico City

A series of sap flow (transpiration, TRP) and energy balance components measurements were carried out in a representative tree hedgerow of Fraxinus uhdei in Mexico City (19° 19' N, 99° 11' W, 2250 m ASL). Measurements of sap flow in the trunks of the trees was selected as an alternative tool instead of eddy covariance or Bowen ratio-energy balance methods in order to determine the energy balance components of the tree canopy. These measurements were made in October (end of the rainy season) and December (dry season) in 1997, from 8:00 to 17:00 LST. TRP showed a unimodal pattern during the day. Mean daily transpiration was higher at the end of the rainy season (1506 g m^–2 d^–1) than in the begining of the dry season (972 g m^–2 d^–1) with maxima rates of 0.075 and 0.046 g m^–2 s^–1, respectively. During the rainy season net radiation (Q_N) was mainly dissipated by latent (Q_E) and sensible (Q_H) heat, 60 and 34 %, respectively. Latent heat increased in the day up to 184 W m^–2. Q_N was dissipated by Q_H and Q_E by 75 and 25%, respectively, and Q_H had a maximum hourly value of 298 W m^–2 during the day (8:00-17:00 LST) in the dry season. Seasonal differences in Q_E and Q_H were probably due to differences of water availability. Heat storage of the tree hedgerow canopy was found to be a negligible component of the energy balance in both seasons. Actual transpiration of the system was always lower than transpiration at equilibrium. This was probably due to a low water availability in the substratum, a high atmospheric evaporative demand and an effective stomatal control. Because the tree hedgerow was completely surrounded by paved areas and wind was coming from a drier side, it is possible that transpiration rates were affected by advection probably supressing TRP.     

Detecting the scales at which birds respond to structure in urban landscapes

Little empirical information exists about how birds respond to urban landscape structure across multiple scales. We explored how the variation in percent tree canopy cover, at four different scales, affected the abundance of bird species across various urban sites in North America. Bird counts were derived from previous studies, and tree patches were measured from aerial photographs that represented areas of 0.2 km², 1.5 km², 25.0 km², and 85.0 km². At each of the four areas, we conducted regressions between bird counts and percent cover of various tree patch sizes. From these analyses, we determined the area (called the best prediction area—BPA) and the patch size (called the best patch size—BPS) that accounted for a significant amount of the variation in bird counts, beyond the variation accounted for by these parameters measured at other scales. BPA and BPS were calculated primarily to take into account the high degree of collinearity that existed among the amount of tree canopy cover measured across the four scales.We calculated BPA and BPS values for a variety of bird species and ascertained whether larger species had relatively larger BPS and BPA values. In the spring, middle-sized to large birds (16.6 g–184.0 g) had relatively larger BPS values than did smaller birds (3.2 g–16.5 g), but in the summer, the largest birds (61.7 g–576.0 g) had small BPS values. Spring BPA values showed a similar result but summer BPA values did not. A majority of birds of all sizes had summer BPA values at the finer scales of 0.2 km² and 1.5 km². Overall, body size was an approximate predictor of the area and patch size at which a species responds to trees in a landscape, but many exceptions did occur. These exceptions could be related to a variety of factors, one being the difficulty in relating human-biased measurements to avian measurements of a landscape. The method described in this study will help researchers design multi-scale studies to address the effect of landscape pattern on different animal species.     

A conceptual framework for the study of human ecosystems in urban areas

The need for integrated concepts, capable of satisfying natural and social scientists and supporting integrated research, motivates a conceptual framework for understanding the role of humans in ecosystems. The question is how to add humans to the ecological models used to understand urban ecosystems. The ecosystem concept can serve as the basis, but specific social attributes of humans and their institutions must be added. Learning and feedback between the human and natural components of urban ecosystems are key attributes of the integrated model. Parallels with familiar ecological approaches can help in understanding the ecology of urban ecosystems. These include the role of spatial heterogeneity and organizational hierarchies in both the social and natural components of urban ecosystems. Although urban watersheds are commonly highly altered, the watershed approach can serve as a spatial basis for organizing comparative studies of ecosystems exhibiting differing degrees of urbanization. The watershed concept can also spatially organize the hierarchically scaled linkages by which the integrated human ecosystem model can be applied. The study of urban ecosystems is a relatively new field, and the questions suggested by the integrated framework can be used to frame ecosystem research in and associated with urban and metropolitan areas.     

Terrestrial vertebrates in urban ecosystems: developing hypotheses for the Gwynns Falls Watershed in Baltimore,Maryland

We review the literature on terrestrial vertebrates in urban and urbanizing areas in terms of the new paradigm in ecology that focuses on the origin, spatial pattern, and current influences of habitat patches. Studies of terrestrial vertebrates have documented differences in species composition along an urban-rural gradient and have identified some of the key land use features associated with these differences. We use information from a database developed for the Gwynns Falls Watershed in Baltimore City and County, Maryland to demonstrate how a study of forest-dependent breeding birds could be used to identify mechanisms that account for differences in the bird communities of forest patches in urban areas, and to provide useful information to planners and managers involved in wildlife conservation and management.     

In-migration, entrepreneurship and rural–urban interdependencies: The case of East Cleveland, North East England

In-migration is a key influence in the process of rural economic development in England, Continental Europe and the US. New arrivals are often viewed in the literature as contributors in new venture creation, as well as catalysts in enhancing rural–urban interdependencies in the countryside. This paper sets out to explore the validity of this view in the case of East Cleveland: a rural area with a tradition of mining and industry, occupying the coastal fringe of the Tees Valley city-region. In doing so, the paper compares this locality with other parts of rural England in order to draw some wider conclusions. Particular emphasis is placed on comparisons with Cumbria, where comparable data are available. The paper argues that the impact of in-migration on the conditions of supply of entrepreneurship is cumulative rather than transformational. This means that it is particularly profound in localities with strong opportunity nexus, reinforcing favourable demand side conditions. However, the ability of in-migrant entrepreneurs to influence rural–urban interdependencies in areas with weak opportunity nexus (such as East Cleveland) is modest.     

无形城市时代城市社会生活特征探析

无形城市是在“后”之时代和全球地域空间这样的时空背景下涌现的新城市形态,它以高流动性和不确定性为主要特征。这种特征成就了特定的城市社会群体,也使得城市社会生活呈现出极具时代感的特征。城市社会心理体现了个性的张扬和自由的释放;城市生活方式因讲究格调和充分享受闲暇而得到提升;城市居民的交往方式既处在一个平等开放的互动平台之上,但也处在互动深度遭受质疑的困境之中。     

The parenting role of African-American fathers in the context of urban poverty

This qualitative study examines low-income African-American fathers' perceptions of their parenting role and the strategies they employ to bring up children in poor urban neighborhoods. Focus groups and individual interviews were conducted with 36 fathers who had contact with their children at least twice a month. Men in the study expressed conventional views of their fathering roles as provider, nurturer, and teacher, but placed the most emphasis on ‘being there’ for their children, as their financial circumstances limited other forms of involvement. Many fathers felt their circumstances to be exacerbated by a hostile child-support system. They desired to teach their children alternatives to the negative practices and values they saw in their urban neighborhoods and to have the skills to prosper in mainstream society. Overall, the findings suggest that many low-income urban fathers already desire to be responsible fathers but see themselves as limited by material and structural challenges. Services and policies that promote the economic stability of low-income fathers are recommended.     

The soil seed bank and its relationship to the aboveground vegetation in deciduous forests in New York City

The soil seed bank was studied in two deciduous forests in Bronx (New York City), NY. The purpose of this study was to determine how the biotic andabiotic differences between urban and rural forests arereflected in urban forest seed banks. Soil samples werecollected in two consecutive years and monitored for emergencein the greenhouse over two years. In 1993, the mean number ofemergents ranged from 4636 to 5373 m^-2 (excluding ferns), or from 6972 to 9651 m^-2 (including ferns). In 1994, the mean number of emergents ranged from 1656 to 2013 m^-2 (excluding ferns), or from 5019 to 5992 m^-2 (including ferns). Graminoids and fernscombined accounted for approximately 70% of all emergents eachyear. Three taxa, Rubus spp., Betula lenta, and Liriodendron tulipifera, comprised 60–80% of the woody emergents and were theonly woody taxa to exhibit delayed germination. A substantialnumber of forbs, graminoids and ferns (15–50%) exhibiteddelayed germination. The nonnative woody species Ailanthusaltissima, Morus alba, and Celastrus orbiculatus were absentfrom the aboveground vegetation of some forest plots yet werepresent at low densities in the seed bank. A greater meandensity of emergents and the presence of nonnative species arethe main differences between the seed banks of these urbanforests and those reported for similar nonurban forests in thisregion.     

A hegemon fighting for equal rights: the dominant role of COC Nederland in the LGBT transnational advocacy network

Networks are alternatives to hierarchical organizational forms. However, actors in networks have different resources at their disposal, and more powerful participants will try to influence the network as a whole. We identify a dominant node in the European LGBT advocacy network, and explore whether a hegemonic actor in the transnational advocacy network will affect less powerful groups' issue framing. Our project uses software that locates the issue network on the internet, highlighting how transnational advocacy work and digital communication have become inextricably connected. We confirm that Cultuur – en Ontspannings Centrum, known as COC Netherland has higher‐than average centrality measures in the LGBT network. Noting the limitations of hyperlink analysis, we conduct a content analysis of select nodes illustrating the impact of a hegemon. We focus on marriage equality and find tentative support for our hypothesis: organizations with links to COC advocate for stronger forms of legalized same‐sex union than do organizations without ties.     

The structure of a micro-bat community in relation to gradients of environmental variation in a tropical urban area

We investigated patterns of community structure (species composition, foraging activity, and nightly foraging patterns) of bats in relation to gradients of environmental variation in a tropical urban area. A total of 32 sites spread equally across eight habitat types were sampled in the city of Townsville, North Queensland, Australia. Each site was sampled on 3 non-consecutive occasions using automated AnaBat systems. Eleven species were confidently identified while a possible four more were identified only to the genus level. Ordination of environmental variables measured at these sites identified two distinct environmental gradients reflecting the degree of urbanisation and foliage density. With increasing urbanisation there was a decline in species richness and total foraging activity. We used regression trees to characterise foraging preferences of each species. This analysis suggested that only one species of Mormopterus was able to exploit the resources provided by urbanisation. This species foraged in areas with higher numbers of white streetlights. The remaining species of bats preferred to forage within close proximity to natural vegetation and with low numbers of streetlights. The density of vegetation in long-established suburbs did not substantially reverse the trend for urban areas to have fewer bat species than original habitats.     

Global cities in Global Commodity Chains: exploring the role of Mexico City in the geography of global economic governance

In this article I assert that global cities are critical nodes in Global Commodity Chains because it is from them that producer services are provided. I explore forward linkages of producer service firms in Mexico City, showing that there are important service flows to companies responsible for the globalization of the 'Mexican' economy. Based on this finding I also indicate reasons why Mexico City is 'on the map' of global cities and of Global Commodity Chains. I argue that both access to local knowledge and close contact to clients are key factors. A third issue dealt with is the position of Mexico City in the geography of governance of commodity chains. The analysis suggests that it is useful to break up global city functions into the management of the world economy and into its command and control, because Mexico City is certainly a place for the former, while the scope of influence exercised from the city is rather limited.     

Assessing the effect of developed habitat on waterbird behaviour in an urban riparian system in Ottawa,Canada

Waterbird species were used to assess the consequences of developed habitat on wildlife behaviour in an urban riparian system along the Rideau River in Ottawa, Canada. Fourteen developed sites and 14 undeveloped sites were surveyed from October 2004 to February 2005. Each site was approached on foot and the first observed behaviour (i.e., fleeing, foraging, resting or swimming) of each individual was recorded. A total of 10,604 behavioural observations were made across 12 taxa. Overall, the fleeing behaviour was observed more often at undeveloped sites. Foraging, resting and swimming behaviours were observed more often at developed sites. We found that seven species fled more often at undeveloped sites, including hooded merganser. This species was also more abundant at undeveloped sites, suggesting that hooded merganser may be more sensitive to anthropogenic disturbance in urban environments than other species that are habituated toward humans. For sensitive species, undeveloped shoreline may serve as a refuge from human disturbance in urban ecosystems.     

Prototyping public friction: Exploring the political effects of design testing in urban space

The use of prototypes as testing instruments has become a common strategy in the innovation of services and products and increasingly in the implementation of “smart” urban policies through living labs or pilots. As a technique for validating hypotheses about the future performance of products or policies, prototyping is based on the idea of generating original knowledge through the failures produced during the testing process. Through the study of an experimentation and prototyping project developed in Santiago de Chile called “Shared Streets for a Low-Carbon District,” I analyse the technique of prototyping as a political device that can make visible (or invisible) certain entities and issues, determining what the experimental entities can do and say. I will show how the technique of prototyping defines modes of participation, what is visible and thinkable, what can be spoken and what is unspeakable. In this sense, I examine two ambivalent capacities of prototyping: as a mechanism of management and enrolment that seeks to prescribe normativities (problem-validating prototype) and as an event that can make frictions tangible, articulating matters of concern and ways to open up alternative scenarios (problem-making prototype).     

Use of urban habitats by coyotes in the vicinity of Banff Alberta

Little information is available on the degree to which coyotes (Canis latrans) use urban habitats. In the past, interactions between coyotes and humans have precipitated several instances of coyote aggression towards humans. Consequently, I analyzed use of urban habitats by coyotes and the possibilities for aggressive encounters with humans. In this study, 11 radio-collared coyotes were monitored between July 1991 and September 1992. Use/availability analysis demonstrated a clear difference in use of natural habitats between summer and winter. Urban habitats were used in direct proportion to availability during all time periods, except during the day in summer when coyotes avoided intense human activity. Campgrounds were not an attraction during either season. For the most part, coyotes in the vicinity of Banff used habitats available to them regardless of human activity. Evidence does not suggest the coyote population in the vicinity of Banff is predisposed to aggression due to familiarity with humans. The relationship between the data and coyote aggression towards humans is discussed.     

The city from its margins: rethinking urban governance through the everyday lives of migrant women in Johannesburg

Drawing on ethnographic data, this article explores migrant women’s relationships and encounters with the state in South Africa’s largest city, Johannesburg. Focusing on the experiences of people in this marginal location, the article re-examines the notion of ‘urban governance’, which is often understood as the realm of formal urban institutions in which the state asserts its authority and regulatory powers. Through the everyday lives of migrant women we see that local urban practices are not simply shaped by the formalism of state rules and regulations, or their informal illegal counterparts. The way migrant women navigate the city, trade on the streets, and interact with the state and other urban actors illustrates that governance is co-constructed by a multitude of regimes, legal and illegal, visible and invisible. Indeed, women’s lives collapse the dichotomy of the official and unofficial, governed and ungoverned city, in ways that allow us to rethink how we conceptualise the city.     

Wildlife conservation in urban greenways of the mid-southeastern United States

Goals related to wildlife conservation are stated or implied in many urban greenway plans, but the actual wildlife conservation value of urban greenways is unclear. We surveyed 72 km. of greenway consisting of 38 different greenway segments in six cities in the mid-southeastern United States to determine the presence or absence of red fox (Vulpes vulpes), grey fox (Urocyon cinereoargenteus), and white-tailed deer (Odocoileus virginianus), and to assess characteristics of the greenways and adjacent lands that might promote or limit the presence of these species in each greenway. We focused on fox and deer because these mammals, while habitat generalists, require diverse habitats within close proximity, and are more sensitive to human disturbance and have larger territories than the majority of urban wildlife in this region. Thus, they can serve as indicator species for these habitat values in urban greenways in the southeastern United States. Field observations and scent station inventories revealed that only 18 of the 38 greenway segments had either fox or deer, 12 had only fox, 6 had fox and deer, and none had deer alone. Greenway segments with more forest cover, wider corridors, greater amounts of adjacent natural or seminatural habitat, and forest connectivity between greenways and nonadjacent natural areas were more likely to have fox or deer present. Characteristics associated with fox and deer presence were not independent of each other. Because greenways with such characteristics tend to be surrounded by less urban areas, adjacent land use is a good predictor of fox and deer presence in the surveyed greenways. Whether greenways that are beneficial to fox and deer can be developed in urban settings is strongly site specific, because the greenway variables that appear most essential to these species are often dictated by the preexisting urban form and the vegetation in the vicinity of the greenway. Because the wildlife conservation value of urban greenways depends greatly on factors external to the greenway, greenways that have fox and deer present today may be particularly vulnerable to future changes in surrounding land use.     

Empirical evidence on intergenerational inequality of tax burdens in the U.S. and Japan

Aggregate data of tax burdens in the U.S. and Japan, classified by period and by age, are decomposed into age, period, and cohort effects using the Bayesian cohort models which were developed to overcome the identification problem in cohort analysis. Main findings are that in both countries the age effects are the largest and the cohort effects are obscure or negligible and that in both countries significant intergenerational inequality is not observed.     

Super-diversity and the art of living in ethnically concentrated urban areas

This article discusses how local diversity is being experienced by Somali immigrants who have previously lived in the Netherlands and are now residing in London. It explores the various challenges and potential advantages of living in homogenous urban areas within a super-diverse city and focuses on three situations: (1) when homogeneity is functional and leads to living in parallel worlds; (2) when homogeneity creates social reproduction, even when located in a super-diverse city; and (3) when people manage to oscillate between both worlds – i.e. between homogenous urban areas and the potential offered by a super-diverse city. The article argues that migrants trace different pathways in the context of super-diversity. They have the ability to operate at different scales – the locale and the cosmopolitan super-diverse metropolis. However, the most vulnerable people have more difficulty in accessing and benefiting directly from the potential offered by super-diversity.     

Self-reinforcing spatial clusters of migration and socio-economic conditions in Finland in 1998–2006

All the time the long economic growth period of 1992–2008 prevailed in Finland, the economic landscape was changing constantly and markedly. We analyse in this article how net migration plagued certain less competitive, mainly rural push-lose municipalities, and boosted in-migration to the pull-win municipalities in metropolitan environments during the very affluent period of 1998–2006. A persistent spatial match of net migration with pull and push conditions is evident in the socio-economically polarized extremes of the Finnish municipalities, indicating the existence of self-reinforcing processes which generate spatial clusters or in more theoretical terms, spatial formations. During the period of economic growth a spatial cumulative causation emerged to bring about a metropolitan type of regional development with only a few metropolitan areas, geographically wide and relatively stable intermediate areas and semi-peripheral, highly rural clusters of pronounced decline. Negative spatial cumulative causation brought about by the impacts of the shrinking primary and service sectors emerged in sparsely populated semi-peripheral municipalities, enforcing the regional polarization in demographic characteristics between growth centres and the poorest municipalities. The observed spatial clusters emerge as classes of their own in the Finnish typology of municipalities, exposing the areas of strongest flux. Our results indicate that various regional policy measures contributed to generating the success of economic evolution within fairly narrow, limited geographical areas.