Prevalence of visual impairment and uncorrected refractive error - report from a Canadian urban population-based study

The prevalence of visual impairment due to uncorrected refractive error has not been previously studied in Canada. A population-based study was conducted in Brantford, Ontario. The target population included all people 40 years of age and older. Study participants were selected using a randomized sampling strategy based on postal codes. Presenting distance and near visual acuities were measured with habitual spectacle correction, if any, in place. Best corrected visual acuities were determined for all participants who had a presenting distance visual acuity of less than 20/25. Population weighted prevalence of distance visual impairment (visual acuity <20/40 in the better eye) was 2.7% (n = 768, 95% confidence interval (CI) 1.8–4.0%) with 71.8% correctable by refraction. Population weighted prevalence of near visual impairment (visual acuity <20/40 with both eyes) was 2.2% (95% CI 1.4–3.6) with 69.1% correctable by refraction. Multivariable adjusted analysis showed that the odds of having distance visual impairment was independently associated with increased age (odds ratio, OR, 3.56, 95% CI 1.22–10.35; ≥65 years compared to those 39–64 years), and time since last eye examination (OR 4.93, 95% CI 1.19–20.32; ≥5 years compared to ≤2 years). The same factors appear to be associated with increased prevalence of near visual impairment but were not statistically significant. The majority of visual impairment found in Brantford was due to uncorrected refractive error. Factors that increased the prevalence of visual impairment were the same for distance and near visual acuity measurements.

Engineering a distributed infrastructure for large-scale cost-effective content dissemination over urban vehicular networks

This paper proposes a practical and cost-effective approach to construct a fully distributed roadside communication infrastructure to facilitate the localized content dissemination to vehicles in the urban area. The proposed infrastructure is composed of distributed lightweight low-cost devices called roadside buffers (RSBs), where each RSB has the limited buffer storage and is able to transmit wirelessly the cached contents to fast-moving vehicles. To enable the distributed RSBs working toward the global optimal performance (e.g., minimal average file download delays), we propose a fully distributed algorithm to determine optimally the content replication strategy at RSBs. Specifically, we first develop a generic analytical model to evaluate the download delay of files, given the probability density of file distribution at RSBs. Then, we formulate the RSB content replication process as an optimization problem and devise a fully distributed content replication scheme accordingly to enable vehicles to recommend intelligently the desirable content files to RSBs. The proposed infrastructure is designed to optimize the global network utility, which accounts for the integrated download experience of users and the download demands of files. Using extensive simulations, we validate the effectiveness of the proposed infrastructure and show that the proposed distributed protocol can approach to the optimal performance and can significantly outperform the traditional heuristics.

Rural-urban differences in reasons for living

 Objective: The suicide rate in Australia is cause for concern, especially the increase in attempted and completed suicides in rural and regional locations. The present study examined reasons for choosing not to commit suicide as a function of residential location. Method: The study involved 655 Victorian residents from four population-based strata; urban, regional city, regional town, and rural. Results: Results from the Reasons for Living Inventory revealed significant differences as a function of residential location. Overall, residents in rural locations reported having significantly more to live for than their urban counterparts. Further analysis of six reasons for living (child, family, moral, social, coping and death-related concerns) showed a pattern whereby residents in rural locations reported having the most to live for, followed by regional residents, and urban residents who reported having the least to live for. Conclusions: These findings are in contrast to increase of suicide rates in rural areas, and highlight the need for a greater understanding of the mechanisms underlying suicidal behaviour.

Unauthorised human use of an urban coastal wetland sanctuary: current and future patterns

Urban expansion brings profound impacts and challenges to many ecosystems, including wetlands. Unauthorised public access to wetland sanctuaries can lead to a number of management problems, such as increasing disturbance to migratory shorebirds. We investigate unauthorised human use of a coastal urban wetland located in Melbourne, Australia, and use current results to predict future patterns of visitation under different management and urban development scenarios. Despite being officially closed to the public, 20.8% of the 574 ha wetland experienced human intrusions during the sampling period. These were most frequent in the section which directly abuts residential development where over 50% of the wetland experienced intrusions. The most frequently observed activities were walking (4.8 ± 4.9 intrusions per observation day), dog walking (8.5 ± 4.5), cycling (3.0 ± 1.8) and motorised trail bike riding (2.5 ± 1.0). There were significant negative relationships between the occurrence of intrusions and distance from the wetland boundary and access points. Walkers and dog walkers were likely to intrude more deeply into the wetlands than other users. We predict that once residential development is completed around the entire perimeter of the wetland that 48% of the total area will be subject to intrusions. This will increase to 58.8% if internal management tracks are opened for public use. We recommend that the current access policy is maintained, and compliance is enhanced through education and additional physical barriers. © 2006 Elsevier B.V. All rights reserved.

Access to social insurance in urban China: a comparative study of rural-urban and urban-urban migrants in Beijing

 Since 1958 the hukou (household registration) system has assigned Chinese citizens either a rural or urban status. Some studies argue that the rural-to-urban migrants in China who do not have urban hukou are not entitled to urban social insurance schemes, due to institutional discrimination, which applies differing treatment to urban and rural hukou (chengxiang fenge). Although rural-urban migrants participate less in the social insurance system than their counterparts with urban hukou, a closer examination of recent policy developments shows that migrants actually do have the legal right to access the system. This implies that discrimination between rural and urban workers has been declining, and distinctions based on household registration status are less able to explain China's current urban transition. This paper provides a new way of examining Chinese migrants' social insurance participation, by adopting a framework that includes both rural-to-urban migrants and urban-to-urban migrants, which are an important, but less studied, migrant group. Among our key findings are that urban migrants are more likely to sign a labour contract than rural migrants; urban migrants have higher participation rates in social insurance than rural migrants; having a labour contract has a greater impact than hukou status in determining whether Beijing's floating population accesses social insurance; and urban migrants who have signed a labour contract have higher participation rates in social insurance than either rural migrants or urban migrants without a labour contract. © 2013 Elsevier Ltd.

Effects of intergroup contact on attitudes of Chinese urban residents to migrant workers

 One consequence of China's marketisation has been the emergence of a 'floating population' - rural Chinese who migrate to China's cities to work. Many urbanites have negative attitudes towards such migrants. To understand how these negative attitudes might be ameliorated, the paper employs Allport's influential contact hypothesis to investigate whether urbanite-migrant friendships affect attitudes. More negative attitudes were observed among males and older urbanites. There was no effect of simply knowing a migrant, supporting Allport's thesis that non-intimate contact is not sufficient to affect attitudes. Friendship alone did not influence attitudes, but interaction effects were detected between having migrant friends and each of age, income and education. Negative attitudes were reduced among urbanites in older, higher-income and higher-education groups if they had a migrant friend. © 2006 The Editors of Urban Studies.

Urban surface temperature behaviour and heat island effect in a tropical planned city

 Putrajaya is a model city planned with concepts of a "city in the garden" and an "intelligent city" in the tropics. This study presents the behaviour of the surface temperature and the heat island effect of Putrajaya. Findings show that heat island intensity is 2 °C on average at nighttime and negligible at daytime. But high surface temperature values were recorded at the main boulevard due to direct solar radiation incident, street orientation in the direction of northeast and southwest and low building height-to-street width ratio. Buildings facing each other had cooling effect on surfaces during the morning and evening hours; conversely, they had a warming effect at noon. Clustered trees along the street are effective in reducing the surface temperature compared to scattered and isolated trees. Surface temperature of built up areas was highest at noon, while walls and sidewalks facing northwest were hottest later in the day. Walls and sidewalks that face northwest were warmer than those that face southeast. The surface temperatures of the horizontal street surfaces and of vertical façades are at acceptable levels relative to the surface temperature of similar surfaces in mature cities in subtropical, temperate and Mediterranean climates. © 2014 Springer-Verlag Wien.

Simplification of arboreal marsupial assemblages in response to increasing urbanization

Arboreal marsupials play an essential role in ecosystem function including regulating insect and plant populations, facilitating pollen and seed dispersal and acting as a prey source for higher-order carnivores in Australian environments. Primarily, research has focused on their biology, ecology and response to disturbance in forested and urban environments. We used presence-only species distribution modelling to understand the relationship between occurrences of arboreal marsupials and eco-geographical variables, and to infer habitat suitability across an urban gradient. We used post-proportional analysis to determine whether increasing urbanization affected potential habitat for arboreal marsupials. The key eco-geographical variables that influenced disturbance intolerant species and those with moderate tolerance to disturbance were natural features such as tree cover and proximity to rivers and to riparian vegetation, whereas variables for disturbance tolerant species were anthropogenic-based (e.g., road density) but also included some natural characteristics such as proximity to riparian vegetation, elevation and tree cover. Arboreal marsupial diversity was subject to substantial change along the gradient, with potential habitat for disturbance-tolerant marsupials distributed across the complete gradient and potential habitat for less tolerant species being restricted to the natural portion of the gradient. This resulted in highly-urbanized environments being inhabited by a few generalist arboreal marsupial species. Increasing urbanization therefore leads to functional simplification of arboreal marsupial assemblages, thus impacting on the ecosystem services they provide.

Urban to forest gradients: suitability for hollow bearing trees and implications for obligate hollow nesters

 Resource availability is a limiting factor influencing the distribution and composition of faunal communities. Globally, hollow bearing trees are a resource required by wildlife at all trophic levels, and are used for a diverse range of ecological functions. In the northern hemisphere avian species act as primary hollow excavators, whereas the southern hemisphere must rely on complex interactions between stochastic events, and eventual decay. Hollow formation is therefore a slow process in the southern hemisphere. In contrast, hollow loss is quite rapid and influenced greatly by anthropogenic impacts.To identify the ecological characteristics driving hollows over an urban to forest gradient as a resource for the powerful owl (Ninox strenua) and its prey we used presence-only modelling. The potential for an area to support tree hollows suitable for powerful owls and their prey was linked to the density of ephemeral rivers, land cover, tree cover and distance from riparian vegetation. The potential for large hollows throughout the landscape, suitable for the powerful owl, was also influenced by density of permanent rivers. Potential habitat for tree hollows, capable of supporting powerful owls and their prey was greatest in forested environments, declining with increased urbanization. However the urban region still supported some smaller tree hollows suitable for arboreal marsupials. Managing for urban dwelling species, is not as simple as retaining old hollow producing trees or providing alternate nesting structures. We also need to mitigate increased mortality associated with built environments (e.g. electrocution, collisions).

A study of the impact of environmental surroundings on personal well-being in urban China using a multi-item well-being indicator

We examine the relationship between atmospheric and water pollution, traffic congestion, access to parkland and personal well-being using a survey administered across six Chinese cities in 2007. In contrast to existing studies of well-being determinants by economists which typically employ single-item indicators, we use the Personal Well-being Index (PWI). We also employ the Job Satisfaction Survey (JSS) to measure job satisfaction, which is one of the variables for which we control when examining the relationship between environmental surroundings and personal well-being. Previous research by psychologists has shown the PWI and JSS to have good psychometric properties in western and Chinese samples. A robust finding is that in cities with higher levels of atmospheric pollution and traffic congestion, respondents report lower levels of personal well-being ceteris paribus. Specifically, we find that a one standard deviation increase in suspended particles or sulphur dioxide emissions is roughly equivalent to a 12-13% reduction in average monthly income in the six cities. © 2010 Springer Science+Business Media, LLC.

Urban stormwater inputs to an adapted coastal wetland : role in water treatment and impacts on wetland biota

The Lake Pertobe wetland system is a semi-natural wetland that has been modified primarily for recreational use. However, this lake system receives stormwater from much of the central business district of Warrnambool City (Victoria, Australia) and serves as a buffer zone between the stormwater system and the Merri River and Merri Marine Sanctuary. This work considers the impact of stormwater inputs on Lake Pertobe and the effectiveness of the lake in protecting the associated marine sanctuary. Sediment contaminants (including heavy metals and polycyclic aromatic hydrocarbons (PAHs)) and water quality parameters within the lake, groundwater and stormwater system were measured. Water quality parameters were highly variable between stormwater drains and rain events. Suspended solids rapidly settled along open drains and shortly after entering the lake. Groundwater inputs increased both salinity and dissolved nitrogen in some stormwater drains. Some evidence of bioaccumulation of metals in the food chain was identified and sediment concentrations of several PAHs were very high. The lake acted as a sink for PAHs and some metals and reductions in Escherichia coli, biological oxygen demand and total phosphorus were observed, affording some protection to the associated marine sanctuary. Nutrient retention was inadequate overall and it was identified that managing the lake primarily as a recreational facility impacted on the effectiveness of stormwater treatment in the system.

Associations between the perceived environment and physical activity among adults aged 55-65 years : does urban-rural area of residence matter?

This study aimed to determine whether associations between the perceived environment and physical activity are moderated by urban-rural status among midolder aged adults. Environmental (safety, aesthetics, physical activity environment) and physical activity (total, leisure, transport) data from 3,888 adults (55 to 65 years) from urban and rural areas of Victoria, Australia, were analyzed. Multinomial logistic regression examined interactions between urban-rural status and environments in associations with physical activity. Significant (P < .05) interactions were evident and indicated positive associations only among older rural adults for both safety and aesthetics with total and transport physical activity (e.g., rural adults reporting higher safety were 91% to 118% more likely to have higher activity than rural adults reporting low safety). In contrast, the physical activity environment was positively associated with leisure activity among only urban adults. Findings suggest that some tailoring of physical activity promotion strategies targeting the environment may be required for urban and rural midolder aged adults.

The geo-historical legacies of urban security governance and the Vancouver 2010 Olympics

In 2004, the discourse of ‘legacy’ was woven into the constitutional fabric of the International Olympic Committee (IOC). Bidding for Olympic events is now premised on procuring post-event legacies that will resonate through local communities and host countries long after the flame is extinguished. Given vast expenditures in security, policing, and emergency management operations at major sporting events, it is notable that the IOC and its official partners have disproportionately under-represented security and policing legacies. This paper addresses research into security and policing legacies of major events by turning much needed empirical attention towards institutional level geographies of security and policing – particularly on legacies of policing and militarisation in Olympic host cities. Accordingly, the paper traces the institutional trajectory of the Military Liaison Unit (MLU) in the Vancouver Police Department who were heavily involved in coordinating the joint civilian–military effort throughout the lifecycle of the Vancouver 2010 Winter Games. Theoretically, the paper furthers Stephen Graham’s (2010) New Military Urbanism that considers the circulation of military expertise between neo-colonial frontiers of military intervention with Western urban spaces. In doing so, this paper unpacks an empirically guided temporal approach that discerns key drivers of militarisation as localised, empirical-based ‘trajectories’ of development of security and policing institutions, which are linked to, and circumscribed by, critical juncture episodes in the context of mega event security. The paper traces processes of the MLU to explain how conditions underpinning the civil–military divide in urban policing, as a series of jurisdictional, institutional, and by extension, geographical configurations have continued, changed or been abandoned in the context of the Vancouver 2010 Olympics. As such, this paper contributes to much needed debate on the controversies and opportunities inherent in security legacies and major events, which implicate the wider securitisation and militarisation of Western cities.