Relationship between ozone and temperature during the 2003 heat wave in France: consequences for health data analysis

BACKGROUND: PAPRICA is a research program designed to estimate the impact on the health of patients with chronic respiratory insufficiency of a prevention strategy based on notification of ozone pollution. The first year of this study was conducted during the 2003 heat wave, and high temperatures were therefore considered as a confounding factor in the data analysis. The aim of the present study was to assess the relationship between ozone and temperature in order to propose a methodology to distinguish between the effects of ozone and temperature on the impact of a prevention strategy with regard to ozone pollution. METHODS: Multivariate analyses were used to identify associated climate and ozone pollution profiles. This descriptive method is of great value to highlight the complexity of interactions between these parameters. RESULTS: Ozone concentration and temperature were strongly correlated, but the health impact of ozone pollution alone will be evaluated by focusing on situations characterized by ozone concentrations above 110 μg/m(3)/8h (air quality guidelines to protect human health defined by the French legislation) and temperatures lower than 26°C, below the discomfort threshold. CONCLUSION: The precise relationship between ambient ozone concentration and temperature identified during the PAPRICA 2003 study period will be used in analysing the PAPRICA health data

On Distance Between Graphs

For a collection of graphs G, the distance graph of G is defined to be the graph containing a vertex for each graph in G, and an edge if the two corresponding graphs differ by exactly one edge. In 1998, Chartrand, Kubicki and Schultz conjectured that every bipartite graph is the distance graph for some collection of graphs. In this paper, we provide methods to combine known distance graphs to generate new larger ones. As observed by Gorše Pihler and Žerovnik in 2008, an important subcase of this conjecture seems to be whether dense graphs can be distance graphs, particularly the complete bipartite graphs. Along these lines, we extend the class of known distance graphs to include K 4,4. We further introduce equivalent formulations of this conjecture and discuss related problems

Rainbow paths

AbstractA k-rainbow path in a graph with colored edges is a path of length k where each edge has a different color. In this note, we settle the problem of obtaining a constructive k-coloring of the edges of Kn in which one may find, between any pair of vertices, a large number of internally disjoint k-rainbow paths. In fact, our construction obtains the largest possible number of paths. This problem was considered in a less general setting by Chartrand et al. (2007) [6]

Étude de la variation au cours d'une période de la constante diélectrique complexe d'une cellule électroluminescente

We have calculated from experimental data on electrical currents, in an electroluminescent cell, the values of the complex dielectric constant. Its variations during a period are connected to brightness and absorbed power variations, permit t-ing one to do an energy balance of the cell.Nous avons calculé, à partir de données expérimentales sur les courants traversant une cellule électroluminescente, les valeurs instantanées de la « constante » diélectrique complexe. Les variations de celle-ci sur une période ont pu être mises en relation avec celles de la luminance et de la puissance absorbée, permettant d'envisager un bilan énergétique de la cellule

Étude de la variation au cours d'une période de la constante diélectrique complexe d'une cellule électroluminescente

Nous avons calculé, à partir de données expérimentales sur les courants traversant une cellule électroluminescente, les valeurs instantanées de la « constante » diélectrique complexe. Les variations de celle-ci sur une période ont pu être mises en relation avec celles de la luminance et de la puissance absorbée, permettant d'envisager un bilan énergétique de la cellule

Groshong versus Hickman catheters.

There has been an increasing need for safe and efficient means of establishing vascular access in the patient with cancer. Recently, the use of percutaneous cannulation of the central veins, using guidewires, venous dilators and tearaway introducer sheaths, has become a popular method of establishing such access. The greatest concerns with the use of such catheters include sepsis, thrombus formation within the vein and catheter malfunction. The current study compared the incidence of these complications with Groshong (Cath Tech CV catheters with Groshong valve) and Hickman (Bard Access Systems vascular access catheters) catheters. Although there was no significant difference in septic complications and thrombus formation between the two groups, there was a significant (p less than 0.05) difference in catheter malfunction. Patients with Hickman catheters experienced significantly less problems with one way intermittent and one way catheters than did patients with Groshong catheters. We conclude that, based on catheter function, the Hickman catheter appears to be a more favorable alternative when compared with the Groshong catheter in the patient with cancer