Caustics are captivating light patterns created by materials bundling or diverting light by refraction or reflection. We know caustics as random side effects, appearing, for example, at the bottom of a swimming pool. In this paper we show that it is possible to control caustic patterns to form almost any desired shape by optimizing the geometry of the reflective or refractive surface generating...

Asthma is a complex condition where genetic and environmental interactions occur at critical periods in development. The focus of this review was the role of environmental exposures on asthma causation. Selected studies published in 2010 and 2011 were reviewed to illustrate the challenge in relating environmental exposure(s) on asthma causation and also to focus on some exposures currently thou...

In our study, the transformation of two most widely used UV filters, benzophenone-3 (BP3) and benzophenone-4 (BP4), in chlorinated water with disinfection reagents sodium hypochlorite (NaClO) and trichloroisocyanuric acid (TCCA) was studied. Based on the HPLC/MS and UV-Vis analysis the formation of two different chlorinated products (5-chloro-2-hydroxy-4-methoxybenzophenone and 3,5-dichloro-2-h...

The potential for generation of disinfection byproducts (DBPs) in swimming pools is high due to the concentrations of chlorine required to maintain adequate disinfection, and the presence of organics introduced by the swimmers. Health Canada set guidelines for trihalomethanes (THMs) in drinking water; however, no such guideline exists for swimming pool waters. Exposure occurs through ingestion,...

Natural swimming pools are artificially created bodies of water that are intended for human recreational bathing and have no chemical disinfection treatment. The microbial populations in four private natural swimming pools were analysed to assess the typical microbiological parameters, establish the origin of faecal contamination in the water, and predict the behaviour of larger systems that ar...

background: a new microextraction method named dispersive liquid-liquid microextraction (dllme) for determination of chloroform in pool water and blood of swimmers after swimming is described. methods: this method was performed based on coupling dispersive liquid-liquid microextraction (dllme) with gas chromatog­raphy-mass spectrometry (gc-ms). methanol and trichloroethylenes were used as the d...

This article describes process evaluation methods for the Pool Cool diffusion trial across 4 years. Pool Cool is a skin cancer prevention program that was found to improve behaviors and environments for sun protection at swimming pools in a randomized efficacy trial, which was followed by a national diffusion trial. The process evaluation focus shifted from measuring program satisfaction to ass...

A large study of the distribution of Clostridium difficile in the environment of the Cardiff area of South Wales was performed with a methodology designed to maximise recovery. A total of 2580 samples was taken, with 184 (7.1%) yielding isolates. The highest yield for C. difficile was obtained from river waters, with 14 (87.5%) of 16 samples from four rivers positive, and from sea water samples...

BACKGROUND Physical activity levels in most affluent countries are low and many people do not meet the current recommendations. Particularly for people with a low income, economic strategies seem promising to stimulate taking part in sports activities. This study investigated the importance of economic restraints for taking part in sports activities as well as perceptions of low-income people t...

OBJECTIVE To analyze the association of physical activity facilities and extracurricular sports activities in schools with physical activity among adolescents. METHODOLOGY/PRINCIPAL FINDINGS We used data collected for the National Survey of School Health in 2012. The national representative sample comprised 109,104 Brazilian students from 2,842 schools. We calculated the prevalence of partici...