What controls the magnitude of the daytime heat sink in a desert city?

The aim of this study was to increase knowledge of the causes of cooling in desert cities. We used a time-series of Landsat images to characterize the changes in daytime land surface temperature during the period of rapid urbanization in Dubai. Changes in land cover and albedo were also quantified from Landsat data and the development of different land use types and variations in urban geometry were characterized. The results demonstrate that urban growth has promoted a heat sink and that all urban land use types contributed to this effect. Vegetation generated the largest cooling effect per unit surface area but impervious surfaces dominated the urban environment and are responsible for the majority of the heat sink created by the city. Changes in albedo were not causally related to the urban heat sink, however, variations in urban geometry, particularly the amount of shading cast by buildings, had some influence on the magnitude of cooling. This study provides evidence that the expansion of the heat sink during urbanization in a desert environment is influenced by the forms of land cover transition, the type of urban land use that is developed, the thermal properties of construction materials used and the geometry of the city environment that is constructed. Future research should concentrate upon understanding these mechanisms in order to plan future developments which maximize cooling and reduce the environmental impacts of desert cities.     

What makes a species synurbic?

The term ‘synurbic’ is sometimes used within the more recent urban ecology literature to refer to a species that colonises or is found within urban ecosystems, but this is too simplistic an interpretation. We consider that the term should be reserved for species populations that have higher densities in urban compared to rural areas, as a quantifiable measure of preferential urban association. This paper clarifies the terms ‘synurbic’ and ‘synurbization’ and considers some of the problems of defining ‘urban’, before detailing some of the positive responses exhibited by urban species that may lead to synurbic populations. It may be particularly important to determine whether responses drive directional selection leading to adaptation and genetic differentiation, or are within the range of expected phenotypic plasticity, and observed responses are discussed within this context. Further investigation of species response to urban environments, including the frequency and significance of adaptation, will be important for understanding the emergence of synurbic populations and their implications for urban biodiversity and management. We hope that the terms defined here will form the basis for comparative studies of urban species.     

What is urban about critical urban theory?

This essay takes as its provocation a question posed by the feminist philosopher Nancy Fraser: “What’s Critical about Critical Theory?” In urban studies, this question has been usefully reframed by Neil Brenner to consider what is critical about critical urban theory. This essay discusses how the “urban” is currently being conceptualized in various worlds of urban studies and what this might mean for the urban question of the current historical conjuncture. Launched from places on the map that are forms of urban government but that have distinctive agrarian histories and rural presents, the essay foregrounds the undecidability of the urban, be it geographies of urbanization or urban politics. What is at stake is a critical urban theory attentive to historical difference as a fundamental constituting process of global political economy and deconstruction as a methodology of generalization and theorization.     

Family or Enterprise? What shapes the business structures of Australian farming?

Australian farmers navigate their contemporary circumstances through the use of different business and legal arrangements that are shaped by the commercial realities of farming and the aspirations of farm-owning households. In posing the question ‘Family or Enterprise?’, this paper examines the extent to which various household and farm business indicators are associated with different forms of farm ownership, namely sole proprietorships, partnerships, trusts and companies. Results from a postal survey of farm enterprises in Victoria, Australia suggest that both household and enterprise factors contribute to the business structure used, although the strongest determinants appear to be those factors that are less well understood in the rural geographical and sociological literature: household composition, farmer age and farm size. Greater scrutiny of the business instruments deployed by farmers to manage family and enterprise pressures should inform expectations of the fate of family farming in advanced financialised economies.     

What Is Emerging? Supply Chains and the Remaking of Asia

A post–World War II Japanese business model has changed the cultural production of capitalism globally. Instead of a drive for uniformity, difference is a resource for the supply chains that have come to dominate Asia—and the world. This article offers a pocket history of the model's emergence and explores its implications for the (non)management of labor and natural resources. Heterogeneity and ruin intertwine in the making of supply chain pockets of political economy. Supply chains link precarity and prosperity, as well as varied cosmologies and ways of life, creating difference-in-connection. What we know as Asia reemerges within the linked niches and nodes of supply chains in which all kinds of difference matter and in which, indeed, global connection flourishes through structures for making and maintaining difference.     

Migration and the life course: is there a retirement transition?

"This paper focuses on pre-elderly (ages 55-64) net migration in the United States for the period 1980-90, to explore the hypothesis that there exists a ?retirement transition' that characterizes pre-elderly migration.... This research uses ordinary least squares regression to compare the effects of demographic, economic, and amenity factors on county-level net migration rates for five age groups: the young (25-44), the middle-aged (45-54), the pre-elderly (55-64), the young-old (65-74), and the old-old (75+). Pre-elderly migration patterns emerge as distinct from those of both younger and older age groups. Their net migration patterns are not fully shaped by labour force considerations. At the same time, pre-elderly migration appears to be driven by factors beyond retirement. These findings are discussed in the context of life-course change and their implications for the ageing baby-boom cohorts [considered]."     

Fishing in a congested sea: What do marine protected areas imply for the future of the Maltese artisanal fleet?

Inshore artisanal fishing in Malta is under intense spatial competition as the coastal zone is fragmented by multiple uses and designations including maritime transport, infrastructure, industrial fisheries, aquaculture, tourism and recreation. This research, adopting a grounded visualization methodology, explains how the artisanal fishing sector has undergone and been affected by ‘spatial squeezing’. Our results show that artisanal fishermen have been forced to give up fishing grounds or co-exist with other uses to the point where the ability to fish is becoming increasingly challenging. These difficulties might escalate with the advent of the marine protected areas (MPAs) which encompass nearly half of the inshore fishing zones. Since there does not seem to be effective MPA consultation mechanisms that elicit the real social, cultural and economic value of artisanal fishing grounds, fishermen feel threatened, alienated and disempowered. This study urges for a more holistic approach to spatial marine planning and accentuates the need of realizing the dependency of the artisanal sector on the inshore zones in the implementation of conservation measures, such that the prolonged existence of the coastal fishing communities is not jeopardized.     

What can the demography of Astrophytum ornatum tell us of its endangered status?

The Cactaceae are prominent members of national and international endangered species lists. This is true for even those that have not been studied in any significant detail, and given the need to assess these species there is still a general lack of information. Demographic studies in the Cactaceae have highlighted several threats some of which are clearly human induced (disturbance), and others that have a biological component (e.g. low survival rates of seedlings). We modelled the population dynamics of Astrophytum ornatum (the southernmost representative of Astrophytum) in one population in central Mexico, during a three year period. We constructed two size classified transition matrices and determined the growth rate (λ), as well as the stochastic log growth rate. We simulated changes in the matrix elements that correspond to the seed bank and the seed-seedling transition as these were the most important bottlenecks to population growth. In both years, the growth rate indicates a declining population, which will face serious problems in the next 2 to 3 decades. The simulations show that the seed bank is not as important as the seed-seedling transition. Any program that aims to restore A. ornatum populations needs to enhance seedling establishment.     

What is the Meaning of ‘Social Mix’? Shifting perspectives in planning and implementing public housing estate redevelopment

This paper unravels a variety of perspectives about the concept of social mix, drawing on a case study of the implementation of a redevelopment project in Melbourne. The first part provides a theoretical overview of two internationally predominant academic debates around policy interpretations of this concept, namely social mix as a means for promotion of social inclusion; and as a state-led form of gentrification. These two arguments are usually presented as one, with social inclusion and reductions of concentrations of disadvantage one side of the ‘social mix policy’ coin, and state-led gentrification the other. This paper contributes to the national and international literature on public housing estate regeneration and social mix policies through exploring the question of whether these two ideas about social mix were shared by different stakeholders as the ‘messy’ process of redevelopment unfurled. Interviews were conducted with public tenants, homeowners and homebuyers, private renters and local service providers at the Carlton Housing Estate to explore the diverse perspectives of various stakeholder groups as estate design and implementation shifted. The study identified that as a result of the global financial crisis and the developers exerting pressure on government there was a gradual move away from perceiving social mix as a policy tool for encouraging social inclusion at Carlton, between public housing tenants and private residents, towards a different form of social mix and inclusion. Contrary to intentions, the revised form of social mix at Carlton was perceived as a means to harness market capital and attract higher income residents to the inner city.     

Space–time prism bounds of activity programs: a goal-directed search in multi-state supernetworks

Space–time prism (STP), which envelops the spatial and temporal opportunities for travel and activity participation within a time frame, is a fundamental concept in time geography. Despite many variants, STPs have been mostly modeled for one flexible activity between two anchor points. This study proposes a systemic approach to construct the STP bounds of activity programs that usually include various possible realizations of activity chains. To that effect, multi-state supernetworks are applied to represent the relevant path sets of multi-activity travel patterns. A goal-directed search method in multi-state supernetworks is developed to delineate the potential space–time path areas satisfying the space–time constraints. Particularly, the approximate lower and upper STP bounds are obtained by manipulating the goal-directed search procedure utilizing landmark-based triangular inequalities and spatial characteristics. The suggested approach can in an efficient fashion find the activity state dependent bounds of STP and potential path area. The formalism of goal-directed search through multi-state supernetworks addresses the fundamental shift from constructing STPs for single flexible activities to activity programs of flexible activity chains.     

The population of the southern Alps: a new equilibrium?

Recent demographic trends in the Alpine areas of France are examined. It is found that a shift of population away from the Cote d'Azur has occurred since 1975. The importance of tourism for population growth in the Alpine areas is noted.