A model for the spread of fire across a fuel bed incorporating the effects of wind and slope

International audienc

Fire spread experiment across Mediterranean shrub: Influence of wind on flame front properties

International audienceA previous termfirenext term spread experiment was conducted in the field under wind-blown conditions. The fuel consists of tall and dense Mediterranean shrub vegetation. The plot area was about 30 m wide and 80 m long. This experiment was conducted not only in order to increase the knowledge and understanding of the previous termfirenext term behaviour in the field but to provide data for the validation of physics based models of previous termfirenext term spread. In particular, the effects of wind on the geometric and thermal properties of the flame front in the field were investigated. The flame temperature along the vertical direction and the radiation emitted ahead of the flame front, were measured. The methodology employed in this experiment and some quantitative measurements of wind velocity and direction, flame geometric properties, are also presented and discussed. The measurements and observations exhibit that the behaviour of the previous termfirenext term and the flame structure character are very different from the one encountered at laboratory scale. These preliminary results show that large scale turbulence influence previous termfirenext term spread and affects the flame shape, temperature and radiation emission

Instrumentation of wildland fire: Characterisation of a fire spreading through a Mediterranean shrub

International audienc

Cell Recovery in Bronchoalveolar Lavage Fluid in Smokers Is Dependent on Cumulative Smoking History

Background: Smoking is a risk factor for various lung diseases in which BAL may be used as a part of a clinical investigation. Interpretation of BAL fluid cellularity is however difficult due to high variability, in particular among smokers. In this study we aimed to evaluate the effect of smoking on BAL cellular components in asymptomatic smokers. The effects of smoking cessation, age and gender were also investigated in groups of smokers and exsmokers. Methods: We performed a retrospective review of BAL findings, to our knowledge the largest single center investigation, in our department from 1999 to 2009. One hundred thirty two current smokers (48 males and 84 females) and 44 ex-smokers (16 males and 28 females) were included. A group of 295 (132 males and 163 females) never-smokers served as reference. Result: The median [5–95 pctl] total number of cells and cell concentration in current smokers were 63.4 [28.6–132.1]610 6 and 382.1 [189.7–864.3]610 6 /L respectively and correlated positively to the cumulative smoking history. Macrophages were the predominant cell type (96.7 % [90.4–99.0]) followed by lymphocytes (2 % [0.8–7.7]) and neutrophils (0.6 % [0–2.9]). The concentration of all inflammatory cells was increased in smokers compared to never smokers and ex-smokers. BAL fluid recovery was negatively correlated with age (p,0.001). Smoking men had a lower BAL fluid recovery than smoking women. Conclusion: Smoking has a profound effect on BAL fluid cellularity, which is dependent on smoking history. Our results performed on a large group of current smokers and ex-smokers in a well standardized way, can contribute to bette

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1.

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field

Modélisation non linéaire du comportement cinétique d’une réaction de Diels-Alder en phase liquide

La modélisation dynamique appliquée à l'étude des systèmes thermochimiques est une approche nouvelle qui permet la détermination de grandeurs thermodynamiques et cinétiques.La réaction de Diels-Alder en phase liquide entre l'anhydride maléique et le méthyl-2-furane est étudiée ; un modèle non linéaire est construit à partir duquel les paramètres cinétiques sont déterminés