GIS analysis of urban schoolyard landcover in three U.S. cities

Although there has been considerable interest in the rejuvenation and greening of inner-city schoolyards for several decades, recent studies on the behavioral and environmental impacts of greenspace, particularly tree cover, suggest that greenspace on schools may be more important than previously understood. However, little is known about the conditions and landcover of urban schoolyards. To understand the structure of the landcover on city schoolyards, this study used Geographic Information System software to classify and compare landcover on 258 U.S. public elementary and middle schools in Baltimore, MD, Boston, MA, and Detroit, MI. For all three cities, schoolyard was found to cover, on average, more than 68% of the school property, which was an average of 1.0–2.5 ha in size. Boston’s schoolyards (circa 1995) were notably smaller from those in Baltimore and Detroit, and they had far more impervious surface. On average, schoolyards were dominated by turf grass and impervious surface, while tree canopy occupied the smallest fraction of schoolyard landcover (approximately 10%). In light of these findings, we conclude by discussing how greening might be achieved on these and other yards.     

河南省城市经济联系时空演化研究

在城市体系所组成的联系网络中．最普遍、最重要的联系是经济联系．城市间的经济联系是城市与区域经济空间结构形成的重要因素。国内许多学者对城市经济联系从各个角度进行了研究,通过对城市经济联系的研究．可以分析区域空间结构演变历史及演变方向和趋势．并对目前各个地区城市群（圈）的形成机理进行解释。     

The role of dispersal and local environment in urban land snail assemblages: an example of three cities in Central Italy

Ecologists increasingly appreciate the central role that urban biodiversity plays in ecosystems, however much urban biodiversity is neglected, especially some very diverse groups of invertebrates. For the first time in southern Europe, land snail communities are analysed in four urban habitats along a geographical gradient of three cities, using quantitative methods and assessing the relative roles of local environmental conditions (“distance from sea”, “distance from city centre”, “vegetation cover”) and spatial effects by principal coordinate analysis of neighbour matrices, redundancy analysis and variation partitioning. A total of 53 species was recorded, a richness similar to that of natural areas. At habitat level, species richness did not show a clear increasing trend from more to less urbanized habitats, but rather a homogeneous pattern. At city level, study areas hosted rather heterogeneous species assemblages and biotic homogenization did not seem to have any impact; indeed, only three species could be considered alien. Variation partitioning showed that land snail communities were mostly structured by environmental factors, even when spatial structures independent of measured environmental variables were included: “vegetation cover” and “distance from city centre” were the environmental variables that explained most of the variation in species composition. The lack of strong spatial structure also unexpectedly suggested that transport by humans aids dispersal of organisms with low mobility, which are usually limited by spatial constraints in natural environments. These results provide ecological and conservation implications for other invertebrate groups, suggesting to set priorities in management strategies that include habitat conservation at local scale.     

Are larger cities more central in urban networks: A meta-analysis

As cities develop more and longer-range external relations, some have challenged the long-standing notion that population size indicates a city's power in its urban system. But are population size and network centrality really independent properties in practice, or do larger cities tend to be more central in urban networks? To answer this question, we conducted a systematic literature search and meta-analysed 41 reported correlations between city size and degree centrality. The results show that population size and degree centrality are significantly and positively correlated for cities across various urban systems (r = 0.77), but the correlation varies by network scale and type. The size-centrality association is weaker for global economic and transportation networks (r = 0.43), and stronger for non-global social and communication networks (r = 0.91). This clarifies seemingly contradictory predictions in the literature regarding the association betweensize and centrality for cities.     

Youth development and afterschool time: policy and programming in large cities

This chapter reviews the issues associated with the growth of after-school programming and the impact on major urban centers.     

Contrasting soil nitrogen dynamics across a montane meadow and urban lawn in a semi-arid watershed

Urbanization substantially increases nitrogen (N) inputs and hydrologic losses relative to wildland ecosystems, although the fate of N additions to lawns and remnant grasslands remains contested. In montane semi-arid ecosystems, N cycling is often closely coupled to snowmelt (the dominant period of infiltration) and snow cover, which impact soil temperature and moisture. Here, we compared soil N dynamics between a fertilized and irrigated urban lawn and nearby riparian meadow in Salt Lake City, Utah during a snow manipulation experiment. Snow removal increased freeze/thaw events but did not affect N pools, microbial biomass, denitrification potential, or soil oxygen (O₂). Mineral N was similar between sites despite lawn fertilization, but dissolved organic N (DON) was four-fold greater (2.1 ± 0.1 mg N l^?1) in lawn soil water. Infiltration was lower in the lawn subsoil, and leaching losses (modeled with Hydrus) were small at both sites (< 2 kg N ha^?1 y^?1) despite substantial lawn fertilization. Lawn soil O₂ fluctuated between 20.9 and 1.6 % following snowmelt and irrigation, but remained near 20 % in the meadow; the lawn had more reducing microsites as indicated by iron speciation. Post-snowmelt potential denitrification was six-fold greater in the lawn than the meadow. Lawns can potentially provide hotspots of denitrification in a semi-arid landscape that exceed some natural riparian ecosystems, whereas DON may represent an increasingly important form of N loss from lawns.     

Connectivity of public urban grasslands: implications for grassland conservation and restoration in cities

An important limitation of studies on the ecological value of urban habitats is the question of habitat connectivity. While connectivity allows spread and genetic exchange of species, isolation can lead to the extinction of populations through inbreeding and loss of genetic diversity. However, while practitioners already start improving urban habitat patches by means of restoration, issues of connectivity have not been taken in account although being crucial for a self-sustaining habitat network. In our study, we evaluate the connectivity of public urban grasslands such as lawns, grasslands in residential areas, playgrounds or parks in the city of Münster, Germany. Employing a graph theory approach, which uses a map (graph) of habitat patches to calculate functional connectivity measures using patch area size and patch connectivity, we studied four groups of different plant dispersal distances (2 m, 20 m, 44 m and 100 m). This approach can be recommended for planning issues due to the output of different indicator values and comparably low data demands. Our results show for the first time, that connectivity of urban grasslands is extremely low for species of short-distance dispersal but slightly increases for long-distance dispersal. Except two larger conglomerations of well-connected patches, urban grasslands were found to be mostly sparsely connected. Thus, future research should focus on options to improve connectivity and to prioritize patches for ecological improvement. The graph theory approach turned out to be a useful tool to analyse urban habitat connectivity but also to illustrate results obtained.

     

Businesswomen and business cliques in three cities: Delhi, Sydney, and Montreal

Les préjugés et la discrimination sont souvent considérés responsables du petit nombre de femmes ambitieuses ayant réussi à atteindre des postes de direction dans les affaires. Le présent article démontre que l'insuccès de bien des femmes est dûà d'autres facteurs plus importants. L'analyse est fondée sur des interviews en profondeur auprès d'un choix de femmes d'affaires de Delhi, Sydney et Montréal.
Prejudice and discrimination are often cited as accounting for the small number of ambitious women who have worked their way up to executive business positions. This paper contends that there are other, more important factors that are responsible for the failure of many women to succeed. The study is based on intensive interviews with a selection of businesswomen resident in Delhi, Sydney, and Montreal     

Diversity and structure of urban forests of Sahel cities in Niger

Urban Ecosystems - Urbanization in the Sahel is constantly competing with and greatly affecting the woody flora in urban areas. Urbanization can replace the species mix, leading to changes in plant...     

On the lookout for danger: House Sparrow alert distance in three cities

Urban Ecosystems - The House Sparrow Passer domesticus, closely associated with human presence along urban–agricultural landscapes and widely distributed outside its native range, has shown...     

Sustainable urban greening strategies for compact cities in developing and developed economies

Urban greening contributes notably to quality of life and ecosystem services in cities. Compact cities in developing and developed countries are commonly beset by greenspace deficit. Based on literature review supplemented by field studies in different cities, a sustainable urban greening strategy is proposed. Urban renewal and new developments without a greening vision could miss the opportunities to bring relief. The public and private sectors can join hands to insert plantable spaces into the urban fabric. Urban greenspaces (UGS) with good connectivity forming a green network to permeate the city constitute the hallmarks of a naturalistic design. Preservation and creation of natural areas with rich biodiversity offer a new dimension to UGS design. Greening benefits could be expressed in economic terms to complement conventional ecological-environmental emphasis. Outstanding trees could receive high-order conservation efforts, and trees in construction sites warrant enhanced protection. Tree transplanting demands an overhaul in concepts and skills. Improving roadside tree planting and maintenance offers a cost-effective way to upgrade the townscape. Ameliorating widespread soil limitations could remove a major hindrance to tree growth. Innovative ideas of development right transfer, street pedestrianization, river and canal revitalization, green roofs and green walls could mobilize hitherto underused plantable resources. Lacking appropriate institutional setup and scientific capability pose intractable bottlenecks. Innovative public policies and greening technologies are needed for sustained improvements. Amalgamating natural and social sciences in a multidisciplinary approach and reinforcing the link between science and public policies could overhaul greening.     

The role of urban indicators in city management: a proposal for Croatian cities

Cities are dynamic economic and social structures that play a dominant role in both national and international economies. They are centers of population, production, consumption, and development. Cities utilize all advantages of economy of scale, proximity, and concentration. On the other hand, they produce high environmental pressures and diminish thereby the quality of life for urban residents. Indicators (environmental, economic, and governance and management) are seen as a tool that would help policy-makers in formulating urban policy that would lead cities towards sustainability and provide assistance for monitoring their development and municipal performance. The aim of this paper is to consider the role that urban indicators can play in city management. We present basic features of urban indicators that will determine their usefulness in urban management. This paper provides the framework to include environmental and economic indicators, as well as governance and management indicators, in successful urban management.     

Gender and housing : The provision of accommodation for young adults in three Mexican cities

The literature on gender and housing is oddly distorted, for it is dominated by research on households which are ‘women-headed’, even where the majority of women may live in households conventionally regarded as being headed by men. This literature shuns the ‘traditional’, male-headed, nuclear household and regards ‘non-traditional’ households as being those headed by single mothers or women living alone. The first part of this paper argues that it is important not to restrict discussion of gender and housing to the problems facing single mothers or women living alone, because there is a danger of rendering the majority of women, once again, invisible.Equating ‘traditional’ and ‘non-traditional’ households with ‘nuclear’ and ‘women-headed’ households, respectively, confuses structure with headship and overlooks cultural variations in what constitutes a ‘traditional’ household — the nuclear household is not necessarily the traditional norm. The second part of this paper explores a little-documented housing arrangement in which large numbers of women are involved in urban Mexico: sharing. ‘Sharing’ occurs when two or more households occupy the same plot of land; one household owns the plot, allowing the other(s) to live there rent-free. Sharing mostly involves the adult sons or daughters of the plot owners, and may be regarded as a variation on the extended household structure. Sons are more likely to be allowed to bring their wives to their parents' home, whereas daughters are more likely to leave. Women living with their in-laws lack security of tenure and there is often conflict between wives and members of their husband's family of origin, particularly their mothers-in-law.The anthropological literature has identified gender relations as the source of conflict between women in extended households. Sharing reduces the potential for conflict by giving the younger household greater autonomy. Furthermore, concern for their daughters' welfare leads many parents to offer accommodation to married daughters as well as sons. Single mothers, however, are more likely to live as part of their parents' household than to share. In this respect, the nuclear household norm is reinforced, since sharing seems to be a privilege accorded only to those who are married.     

Relationship between land cover and insectivorous bat activity in an urban landscape

Despite the clear importance of conserving biodiversity in urbanized areas, research on how bats are influenced by urbanization has is only recently catching up to the more established body of research for urban birds. Much of the extant research has been limited to urban parks and other natural areas. Here I present the results of an acoustic survey of bats throughout the agricultural/forest/suburban/urban mosaic of the Minneapolis-St. Paul metropolitan area. Activity indices by each of the six recorded species (Eptesicus fuscus, Lasiurus cinereus, Lasiurus borealis, Lasionycteris noctivagans, Myotis sp., and Perimyotis subflavus) were used as response variables with land cover variables in a series of statistical models. Because bats may perceive the landscape at different scales, candidate models included land cover variables within 100, 500 and 1,000?m of the sampling location. Activity of L. noctivagans was negatively related to the amount of impervious surface and open habitat in the immediate landscape. L. borealis activity was positively correlated with immediate tree cover and with impervious surface at the 1,000?m scale. Tree cover and proximity to water were positively related to activity levels of Myotis sp., L. cinereus and P. subflavus, but only the latter was influenced by the amount of surrounding impervious surface. These results suggest that a one-size fits all approach to bat conservation in human modified landscapes is not appropriate, but also that certain species appear to do well in urban environments provided that there is sufficient tree cover.     

Lean production and work-related musculoskeletal disorders: overviews of international and Swedish studies

This paper aimed at summarizing the knowledge of the relationship between Lean and work related musculoskeletal disorders (WMSD), and WMSD risk factors, in manufacturing companies. Literature search processes identified 23 publications studying this, in scientific journals. Eight included measurements of WMSD; three were mostly negative, two showed mixed results, one showed no results and two were mostly positive. Eighteen publications included measurements of WMSD risk factors; seven showed mostly negative results, eight showed mixed results, two showed mostly positive results and one was inconclusive. Three literature reviews were identified, which studied this question; two were mostly negative, while the third was inconclusive. Also, 12 publications of grey literature studying Lean and WMSD risk factors in Swedish organizations were identified; nine showed mixed results, two showed mostly positive results and one showed mostly negative results. Due to the varying quality and study design of the publications, together with the few identified studies, it is difficult to compare them. The context and the implementation also likely affect the results. The general conclusion was that a Lean implementation may increase the risk of WMSD and risk factors for WMSD, if it is not accompanied with an ergonomic intervention.     

From foster care to juvenile justice: Exploring characteristics of youth in three cities

Children placed in foster care are at risk for becoming involved with the juvenile justice system. This study documents the rates at which children involved with foster care enter the juvenile justice system (crossover or dually involved), and the factors associated with this risk. We utilize multiple birth cohorts and prospective, longitudinal data from birth to maturity separately in three major American cities. Analyses consider integrated administrative records from multiple birth cohorts representing populations in Cook County (Chicago; N = 26,003), Cuyahoga County (Cleveland; N = 10,284), and New York City (N = 13,065). Crossover rates ranged from 7 to 24%. African American males, and children who experienced congregate care were at highest risk for juvenile justice involvement. Older age at first foster care placement signaled progressively greater risk, as did more foster care spells for those first placed as infants. We discuss findings in terms of developmental theory, and as actionable intelligence to inform prevention, practice, and policy.     

Interurban flows of population and occupational skills to three cities in Nigeria

"This article examines interurban flows of population and occupational skills to three cities in Nigeria. The analyses are based on sample survey data collected in the cities of Benin, Ibadan, and Kano in 1973 and 1974." The results indicate that most migrants were repeat movers, and that interurban migration predominated. However, whereas men brought a wide range of occupational skills, most women came with traditional-type skills or as housewives.