The sources of the urban wage premium by worker skills: Spatial sorting or agglomeration economies?

We estimate the respective importance of spatial sorting and agglomeration economies in explaining the urban wage premium for workers with different sets of skills. Sorting is the main source of the wage premium. Agglomeration economies are in general small, but are larger for workers with skills associated with non‐routine job tasks. They also appear to involve human capital accumulation, as evidenced by the change in the wage of workers moving away from denser regions. For workers with routine jobs, agglomeration economies are virtually non‐existent. Our results provide further evidence of spatial density bringing about productivity advantages primarily in contexts when problem‐solving and interaction with others are important.     

Non-profit housing,a tool for metropolitan cohesion? The case of the Vienna–Bratislava region

Non-profit housing has a long history both in Austria and in Slovakia, even if recent socio-economic and political transformations question this model born in the nineteenth century. This type of housing is considered as affordable housing according to a generalist conception in Austria and a residual one in Slovakia. But in spite of divergences in their national housing policies, both countries are facing common challenges which are epitomised in the Vienna–Bratislava region. This article analyses the role of non-profit housing in bringing more cohesion to a growing but fragmented metropolitan region.     

Validating verdancy or vacancy? The relationship of community gardens and vacant lands in the U.S.

Community gardens have gained attention and support in recent years because of a range of expected benefits and outcomes, and they are one of many examples of transformations of vacant land into green space. While the improvements to vacant or underutilized land are lauded, the practice of community gardening is underpinned by the assumption that it is a temporary practice on temporarily-available land. This assumption, which is at times implicit and at others explicit, maintains that support for community gardens—technical assistance and especially access to land—can be temporary. Through a genealogy of community garden advocacy in the U.S., we find that a dominant narrative of community gardening as a means to an end has been continuously reproduced for more than a century in large part by government agencies and philanthropic organizations. In recent decades, community gardeners have become key actors in advocacy, and although they portray gardening as a meaningful part of everyday city life, they also reproduce that narrative of temporariness by promoting it as a means to address various issues. We argue that this tension between means and ends—especially coming from community gardeners—is problematic. It is a challenge for community gardeners and the many other producers of green space on supposedly vacant land because their means-oriented discourse takes precedence in the public imagination; it perpetuates the notion that the land is ultimately still vacant.     

The re-emergence of core region growth: a return to the metropolis?

Recent trends in migration in the United States are reviewed, focusing on the links between regional and metropolitan population change. Three explanations for the counterurbanization phenomenon of the 1970s are presented and their implications for future migration trends considered. The author concludes that "while 1970s core region declines may have been strongly linked to the counterurbanization process, post-1980 core region gains do not appear to signal a return to the metropolis."     

Computer-aided qualitative data analysis: panacea or paradox?

Following the methodological debate within the construction management research community in the 1990s, research studies adopting inductive methodologies have increased. Many such projects have adopted computer-aided qualitative data analysis in order both to facilitate the research process and to ensure methodological rigour and transparency. However, there remains a paucity of critical discourse within the construction management research literature about the impact of such approaches on the depth and rigour of the resulting analyses. This paper posits that so-called computer-aided approaches have the potential to affect detrimentally the outcomes of construction management research if researchers see such tools as a panacea for ensuring the rigour and transparency of their work. Paradoxically, computer-aided approaches often restrict rather than aid the analytical process. The paper draws upon the authors' experiences of using a leading package from which a number of considerations for the use of computers in qualitative data analysis are discussed. It is concluded that the research community would benefit from an open debate on whether computer packages really do provide a panacea to the analysis of qualitative data in applied construction management research projects or whether their use merely provides a label with which to convince sceptical positivists of the rigour of inductive research techniques.     

How does wage polarization affect productivity? The case of Spanish regions

The effect of wage polarization on total factor productivity (TFP) in the Spanish regions between 2004 and 2012 is analysed using dynamic panel estimates. The main finding of this research is that there seems to be some evidence that polarization can affect productivity negatively. Although the specification of the models seems to be correct, the time period studied is brief, so these results should be interpreted with caution.     

Emergency homeless shelter use in the Dublin region 2012–2016: Utilizing a cluster analysis of administrative data

Arising out of a decade of economic recession and austerity, Ireland is currently in the grip of a severe housing crisis marked by weak housing supply, rapidly rising house prices and rents and a dramatic increase in homelessness that is placing severe pressure on the State's emergency accommodation system. This article utilises data from a national homelessness services database (PASS system), which captures live information on service user interactions for all state funded NGO and local authority homeless services, to examine the patterns of emergency accommodation use by the homeless population in Dublin City. The paper applies a k-means cluster analysis to determine different subgroups of Dublin's homeless population (n = 12,734) and analyses their rate of movement through homeless services between the years 2012 and 2016. A temporary cluster (78%) experienced a small number of homeless episodes for relatively short periods of time, while an episodic cluster (10%) experienced multiple homeless episodes also for a short period of time. The chronic cluster (12%) experienced a small number of homeless episodes but with long stays in emergency shelter. Results for Ireland show patterns similar to those reported in the US, Canada and Denmark, where a small number of chronic users of homeless accommodation account for a disproportionately large share of resources (i.e. 50% of total bed nights). The findings have implications for the operation of emergency homeless accommodation in Ireland and, in particular, the targeting of interventions and the re-directing of resources away from emergency accommodation responses towards a more effective emergency accommodation system for all stakeholders.     

Vegetation in the early landscape art of the Sydney region, Australia: accurate record or artistic licence?

With its relatively short European history, Australia's earliest paintings may provide information on both the pre-European landscape and changes since first settlement. The pictorial record is examined as historical documentation of natural landscape, particularly vegetation, by considering artistic depictions of the region around Sydney, New South Wales, from initial settlement in 1788 to the early 1850s. Critical comment relating to the accuracy of the landscape paintings is examined by reference to the pictures and to Sydney's dramatically varied geology that shaped the landscapes and the vegetation communities that artists painted. There are few detailed studies of Australian landscape painting and much of the critical comment is found to be generalized and only partly accurate, including the persistent criticism that artists misrepresented Australian environments for a multitude of reasons. The pictorial record displays consistent observation of the real variation in landscape character, and in vegetation structure, communities and species. It also appears to provide interesting evidence of differential impact of fire, indicating different pre-settlement fire regimes in different landscape types.     

The elusive inequality-economic growth relationship: are there differences between cities and the countryside?

The inequality-economic growth debate remains unsettled. For instance, classical theories point to the importance of incentives in increasing growth, but recent theories stress social and political disruptions as causal factors in inhibiting growth. Conflicting empirical evidence has not helped, with contradictory findings arising when employing different samples and alternative econometric techniques. This study re-examines the linkage by contending that it is not surprising that past research uncovered conflicting findings. For example, the transmission mechanism through which inequality/economic incentives influence economic growth can be affected by factors such as urbanization and social cohesion. Using US county data over the 1990s, the empirical results suggest that the econometric results are unstable when considering weighted regressions over the entire sample. Yet, consistent with our hypothesized relationships, when separately considering metropolitan and nonmetropolitan samples, there is a positive inequality-growth link in the urban sample, with the opposite holding in the nonmetro case. Implications for both the inequality-growth literature and for public policy are discussed.     

Stress–strain relationship in axial compression for concrete using recycled saturated coarse aggregate

In this work the stress–strain curve of the recycled concretes was determined by replacing different percentages of the natural coarse aggregate with recycled coarse aggregate (20%, 50% and 100%). The results made it possible to establish the differences between the stress–strain relationship of a conventional concrete and this relationship for a recycled concrete depending on the percentage of replacement. In this way, it was found that the longitudinal strain of the recycled concretes increases with the percentage of recycled coarse aggregate used.Finally, using the experimental results, an analytical expression of the stress–strain curve accounting for the percentage of replacement was developed. The verification of the proposed model equation was done by comparing it to the experimental data. The results show that the proposed model equation satisfactorily describes the effect of the recycled aggregate on the stress–strain curve.     

To instruct or not? The engineer's dilemma

A recent research project explored the sources of relatively higher value and/or more frequent construction claims in civil engineering projects in Hong Kong. Fourteen common sources of claims were cited to seek views from the industry as to the perceived frequencies, magnitudes and avoidabilities of claims from such sources. One of the significant sources was identified as ‘instructions not being issued’, with reference to the provision in most standard civil engineering contracts that ‘the engineer’ shall issue necessary instructions for the purposes of completion of the Works. The study reported here focuses on the possible responses of ‘the engineer’ when the contractor requests instructions/information. Also the study examines the possible generation of construction claims therefrom. Eleven practitioners who were familiar with such matters were issued a questionnaire which described ten typical construction problem scenarios (cases) where contractors may request instructions. The responses are summarized and the basis for reaching each of these decisions is analysed. An example of the eleven detailed responses to one of the cases is presented to demonstrate the divergence of perceptions on each issue and the consequent different recommendations. Strategies to minimize the claims and disputes arising from such scenarios are developed, based on resolving the evident conflicts between the reasons for such divergences.     

Estimation of the soil parameters in Balçova region using multiple geophysical approach

This study aimed to reveal the soil properties in the research area by using various geophysical methods. Physical parameters determining soil characteristics give us a chance to approach how the soil behaves during an earthquake. Thus, precautions can be taken to minimize earthquake damage. Also, safe construction against earthquake effects is important. The studied area is a tectonically and geothermally active area. İzmir Fault zone is passing through the investigation area and trending E–W direction. To investigate soil parameters at this active tectonic region, microtremor method data were recorded and the multichannel analysis of surface waves (MASW) method at 27 profiles was implemented in the study area. Additionally, these methods were supported by the spatial auto correlation (SPAC) method in center spot. Shear wave velocities up to 30 m, soil classification according to the National Earthquake Hazards Reduction Program (NEHRP), site amplification, predominant site period, amplification factor, ground vulnerability index, and shear wave velocity changes up to 300 m were obtained by evaluating the data collected from the applied geophysical methods. V_S30 values varied between 700 and 1100 m/s in the southernmost part of the study area, corresponding to a C and B type as soil classification. While the predominant period values were taken as the lowest value of 0.2 s, it was observed to increase up to 5.5 s on the alluvial unit in the northern parts of the study area. The ground vulnerability index, which is directly related to the probability of earthquake damage, was found to be quite high in some parts of the study area. In this paper, we propose microzonation maps for the Balçova district, based on the variation of the soil dynamic parameters.

     

Public transport decline in Melbourne: A question of density or service?

Public transport systems in Melbourne and other Australian cities have experienced steady decline in usage over the past 50 years. Concerned commentators and policy makers have debated the likely reasons behind this downward trend. The most widely held opinion is that sprawling low-density, post-Second World War urban form is the best explanation for the low levels of usage. However, some other authors argue that low usage rates can be better explained by the poor level of service offered in most areas of the city. This debate has centred largely on comparisons between Melbourne and other cities. Whilst recognising the complexity of this issue, this paper is focused on an analysis of the effect that urban density and service quality have on the operation of local public transport services in Melbourne. The paper concludes that Melbourne's low public transport usage rates are best explained by the poor levels of service quality offered by public transport systems.     

Victims or victors? Managing the revolution

Silicon Valley, California is the epicentre of the information technology age. The `Valley' has become an icon for the hectic, interconnected world we live in. Seismic shifts are something this particular community knows all about. The San Andreas fault is built into the fabric of Californian life. `When will the big one be?' is a question lurking in the back of everyone's mind in the `Valley'. Perhaps that question should be in the back of the World's collective mind as well. Is this the big one for society as we know it?     

Core–periphery dynamics in the Portland, Oregon, region: 1982–2006

The relative strength of positive and negative spillovers of urban development is a long-standing and contested issue in regional and development economics, and the search for spread and backwash effects of development in urban core economies goes back at least 50 years. Using data from IMPLAN and the Bureau of Economic Analysis to develop multiregional input–output models, we developed estimates of core–periphery economic interdependence (sales and purchases of goods and services and commuting of workers between the core and the periphery) of the Portland, Oregon, region for 1982 and 2006. We explored whether the changing flows of sales and purchases, spillovers and commuting between 1982 and 2006 suggested a dominance of spread effects or backwash effects. We found increased commuting between periphery and core, decreased core–periphery transactions, and smaller core-to-periphery spillovers and periphery-to-core spillovers in both goods and services. Our findings do not point to a clear dominance of spread or backwash effects. Results showing smaller core-to-periphery and periphery-to-core multipliers/spillovers suggest that spread effects related to trade in goods and services weakened between 1982 and 2006. Our findings of increased commuting are consistent with enhanced spread effects in labor markets.     

The electricity supply industry in Germany: market power or power of the market?

This paper analyses the electricity supply industry in Germany, which was liberalized in April 1998. Noticeable aspects are the eligibility of all end-users, the lack of constraints on the vertical industry structure and the option for negotiated third party access. There is no sector-specific regulation. This paper argues that the vertically integrated firms concentrate on excessive network access charges, whereas the stages generation and retail appear to be relatively competitive. Empirical evidence suggests that in Germany network access charges make up a significantly higher share of end-user prices than in the UK, which is used as regulation-benchmark.