The rise of low-cost sensing for managing air pollution in cities

Ever growing populations in cities are associated with a major increase in road vehicles and air pollution. The overall high levels of urban air pollution have been shown to be of a significant risk to city dwellers. However, the impacts of very high but temporally and spatially restricted pollution, and thus exposure, are still poorly understood. Conventional approaches to air quality monitoring are based on networks of static and sparse measurement stations. However, these are prohibitively expensive to capture tempo-spatial heterogeneity and identify pollution hotspots, which is required for the development of robust real-time strategies for exposure control. Current progress in developing low-cost micro-scale sensing technology is radically changing the conventional approach to allow real-time information in a capillary form. But the question remains whether there is value in the less accurate data they generate. This article illustrates the drivers behind current rises in the use of low-cost sensors for air pollution management in cities, whilst addressing the major challenges for their effective implementation.

Environmental contributions to autism: Explaining the rise in incidence of autistic spectrum disorders

The incidence of autism spectrum disorders, a heterogenous group of neurodevelopmental disorders is increasing. In response, there has been a concerted effort by researchers to identify environmental risk factors that explain the epidemiological changes seen with autism. Advanced parental age, maternal migrant status, maternal gestational stress, pregnancy and birth complications, maternal obesity and gestational diabetes, maternal vitamin D deficiency, use of antidepressants during gestation and exposure to organochlorine pesticides during pregnancy are all associated with an increased risk of autism. Folic acid use prior to pregnancy may reduce the risk of autism. Exposure to antenatal ultrasonography, maternal gestational cigarette and alcohol use do not appear to influence the risk of autism in offspring. There is little evidence that exposure to environmental toxins such as thimerosal, polybrominated diphenyl ethers and di-(2-ethylhexyl) phthalate in early childhood increases the risk of autism. Apart from birth complications, the current evidence suggests that the majority of environmental factors increasing the risk of autism occur in the antenatal period. Consistent with the rise in incidence in autism, some of these environmental factors are now more common in developed nations. Further research is required to determine how these environmental exposures translate to an increased risk of autism. Understanding how these exposures alter neurodevelopment in autistic children may inform both the aetiopathogenesis and the strategies for prevention of autism.

Food justice or food sovereignty? Understanding the rise of urban food movements in the USA

As world food and fuel prices threaten expanding urban populations, there is greater need for the urban poor to have access and claims over how and where food is produced and distributed. This is especially the case in marginalized urban settings where high proportions of the population are food insecure. The global movement for food sovereignty has been one attempt to reclaim rights and participation in the food system and challenge corporate food regimes. However, given its origins from the peasant farmers' movement, La Via Campesina, food sovereignty is often considered a rural issue when increasingly its demands for fair food systems are urban in nature. Through interviews with scholars, urban food activists, non-governmental and grassroots organizations in Oakland and New Orleans in the United States of America, we examine the extent to which food sovereignty has become embedded as a concept, strategy and practice. We consider food sovereignty alongside other dominant US social movements such as food justice, and find that while many organizations do not use the language of food sovereignty explicitly, the motives behind urban food activism are similar across movements as local actors draw on elements of each in practice. Overall, however, because of the different histories, geographic contexts, and relations to state and capital, food justice and food sovereignty differ as strategies and approaches. We conclude that the US urban food sovereignty movement is limited by neoliberal structural contexts that dampen its approach and radical framework. Similarly, we see restrictions on urban food justice movements that are also operating within a broader framework of market neoliberalism. However, we find that food justice was reported as an approach more aligned with the socio-historical context in both cities, due to its origins in broader class and race struggles.

Optimum position of steel outrigger system for high rise composite buildings subjected to wind loads

The responses of composite buildings under wind loads clearly become more critical as the building becomes taller, less stiff and more lightweight. When the composite building increases in height, the stiffness of the structure becomes more important factor and introduction to belt truss and outrigger system is often used to provide sufficient lateral stiffness to the structure. Most of the research works to date is limited to reinforced concrete building with outrigger system of concrete structure, simple building plan layout, single height of a building, one direction wind and single level of outrigger arrangement. There is a scarcity in research works about the effective position of outrigger level on composite buildings under lateral wind loadings when the building plan layout, height and outrigger arrangement are varied. The aim of this paper is to determine the optimum location of steel belt and outrigger systems by using different arrangement of single and double level outrigger for different size, shape and height of composite building. In this study a comprehensive finite element modelling of composite building prototypes is carried out, with three different layouts (Rectangular, Octagonal and L shaped) and for three different storey (28, 42 and 57-storey). Models are analysed for dynamic cyclonic wind loads with various combination of steel belt and outrigger bracings. It is concluded that the effectiveness of the single and double level steel belt and outrigger bracing are varied based on their positions for different size, shape and height of composite building.

The rise and fall of Rentboy.com

Earlier this week, the New York Police Department in partnership with Homeland Security arrested seven people and seized a number of documents pertaining to the website Rentboy.com. Although the website purports to help men connect for companionship only, authorities allege that it has been used to “facilitate the promotion, management, establishment, and carrying on of an unlawful activity, namely an enterprise involving prostitution”. Unlike Australia, which started the decriminalisation of sex work as early as 1979, sex work is illegal across all of the USA, save a few counties in Nevada where it is subject to heavy regulation. The raid on Rentboy.com raises important questions about sex work, including its visibility, consumer demand for such services, and the ongoing marginalisation of those who buy and sell sexual services...

Investigating sea level rise due to global warming in the teaching laboratory using Archimedes’ principle

A teaching laboratory experiment is described that uses Archimedes’ principle to precisely investigate the effect of global warming on the oceans. A large component of sea level rise is due to the increase in the volume of water due to the decrease in water density with increasing temperature. Water close to 0 °C is placed in a beaker and a glass marble hung from an electronic balance immersed in the water. As the water warms, the weight of the marble increases as the water is less buoyant due to the decrease in density. In the experiment performed in this paper a balance with a precision of 0.1 mg was used with a marble 40.0 cm3 and mass of 99.3 g, yielding water density measurements with an average error of -0.008 ± 0.011%.

An alternative approach to describing agility in sports through establishment of a relationship between velocity and radius of curvature

Agility is an essential part of many athletic activities. Currently, agility drill duration is the sole criterion used for evaluation of agility performance. The relationship between drill duration and factors such as acceleration, deceleration and change of direction, however, has not been fully explored. This paper provides a mathematical description of the relationship between velocity and radius of curvatures in an agility drill through implementation of a power law (PL). Two groups of skilled and unskilled participants performed a cyclic forward/backward shuttle agility test. Kinematic data was recorded using motion capture system at a sampling rate of 200 Hz. The logarithmic relationship between tangential velocity and radius of curvature of participant trajectories in both groups was established using the PL. The slope of the regression line was found to be 0.26 and 0.36, for the skilled and unskilled groups, respectively. The magnitudes of regression line slope for both groups were approximately 0.3 which is close to the expected 1/3 value. Results are an indication of how the PL could be implemented in an agility drill thus opening the way for establishment of a more representative measure of agility performance instead of drill duration.

The 'rise' of Aboriginal women, from domesticated cow to cash cow

The recent claims from former Queensland Labor MP Gary Johns that “a lot of poor women in this country, a large proportion of whom are Aboriginal, are used as cash cows” who are “kept pregnant and producing children for the cash” are somewhat alarming, but not surprising...

In vivo velocity vector imaging and time-resolved strain rate measurements in the wall of blood vessels using MRI

In this paper, we present a new approach for velocity vector imaging and time-resolved measurements of strain rates in the wall of human arteries using MRI and we prove its feasibility on two examples: in vitro on a phantom and in vivo on the carotid artery of a human subject. Results point out the promising potential of this approach for investigating the mechanics of arterial tissues in vivo.

Bubble play

Observing peculiar entoptic phenomena relating to a large air bubble inside his eye provided a little comedy relief for Professor Nathan Efron during his otherwise taxing ophthalmic journey of retinopexy, cryopexy, vitrectomy and IOL surgery.