Spatial analysis of air pollution and childhood asthma in Hamilton, Canada: comparing exposure methods in sensitive subgroups

<p>Abstract</p> <p>Background</p> <p>Variations in air pollution exposure within a community may be associated with asthma prevalence. However, studies conducted to date have produced inconsistent results, possibly due to errors in measurement of the exposures.</p> <p>Methods</p> <p>A standardized asthma survey was administered to children in grades one and eight in Hamilton, Canada, in 1994–95 (N ~1467). Exposure to air pollution was estimated in four ways: (1) distance from roadways; (2) interpolated surfaces for ozone, sulfur dioxide, particulate matter and nitrous oxides from seven to nine governmental monitoring stations; (3) a kriged nitrogen dioxide (NO₂) surface based on a network of 100 passive NO₂monitors; and (4) a land use regression (LUR) model derived from the same monitoring network. Logistic regressions were used to test associations between asthma and air pollution, controlling for variables including neighbourhood income, dwelling value, state of housing, a deprivation index and smoking.</p> <p>Results</p> <p>There were no significant associations between any of the exposure estimates and asthma in the whole population, but large effects were detected the subgroup of children without hayfever (predominately in girls). The most robust effects were observed for the association of asthma without hayfever and NO₂LUR OR = 1.86 (95%CI, 1.59–2.16) in all girls and OR = 2.98 (95%CI, 0.98–9.06) for older girls, over an interquartile range increase and controlling for confounders.</p> <p>Conclusion</p> <p>Our findings indicate that traffic-related pollutants, such as NO₂, are associated with asthma without overt evidence of other atopic disorders among female children living in a medium-sized Canadian city. The effects were sensitive to the method of exposure estimation. More refined exposure models produced the most robust associations.</p

International collaborative project to compare and track the nutritional composition of fast foods

Background: Chronic diseases are the leading cause of premature death and disability in the world with over-nutrition a primary cause of diet-related ill health. Excess quantities of energy, saturated fat, sugar and salt derived from fast foods contribute importantly to this disease burden. Our objective is to collate and compare nutrient composition data for fast foods as a means of supporting improvements in product formulation. METHODS/DESIGN: Surveys of fast foods will be done in each participating country each year. Information on the nutrient composition for each product will be sought either through direct chemical analysis, from fast food companies, in-store materials or from company websites. Foods will be categorized into major groups for the primary analyses which will compare mean levels of saturated fat, sugar, sodium, energy and serving size at baseline and over time. Countries currently involved include Australia, New Zealand, France, UK, USA, India, Spain, China and Canada, with more anticipated to follow. DISCUSSION: This collaborative approach to the collation and sharing of data will enable low-cost tracking of fast food composition around the world. This project represents a significant step forward in the objective and transparent monitoring of industry and government commitments to improve the quality of fast foods.E Dunford is supported by a Sydney Medical School Foundation scholarship and B Neal by an Australian Research Council Future Fellowship.http://www.biomedcentral.com/1471-2458/12/559am201

The flooding sink: a new approach to local area networking

A new local area networking technology is presented. The approach is based on an old routing algorithm called flooding - forward messages to all neighboring nodes. The problem with this algorithm is that the network is deluged with duplicate messages. The solution is a simple device which uses local memory to detect and ignore redundant messages, thus also acting as a message sink. Networks based on this device are shown to be more flexible and realiable than current networks. Flooding also has the advantage that any messages lost due to transmission errors are quickly replaced by one of the copies. This makes much of the usual low-level 'hand-shake' protocols unnecessary. When the low-level protocols are omitted, significant performance improvements are achieved. Simulation results are presented which show that this flooding technology performs better than current CSMA and ring technologies

Object Properties in the Raven System

Raven consists of an object-oriented programming language and a runtime system that supports distributed and multiprocessor computing. This paper describes the motivation behind the design of the object property scheme used in the Raven system, the behavioral semantics for each of the properties supported, and schemes by which inter-object dependencies can be described. Raven provides a set of system-defined properties, such as concurrency control and persistence, as well as support for user-defined properties. Raven is distinguishable from similar systems in several fundamental ways: the behavioral semantics of each system supported property is truly orthogonal to those of the others, allowing properties to be combined without side effects; the system allows the seamless integration of user-defined properties into the property scheme; and all properties (even user properties) can be assigned dynamically, in any combination, to objects, even after object creation. Property support is p..