25 research outputs found

    Modelling Jets, Tori and Flares in Pulsar Wind Nebulae

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    In this contribution we review the recent progress in the modelling of Pulsar Wind Nebulae (PWN). We start with a brief overview of the relevant physical processes in the magnetosphere, the wind-zone and the inflated nebula bubble. Radiative signatures and particle transport processes obtained from 3D simulations of PWN are discussed in the context of optical and X-ray observations. We then proceed to consider particle acceleration in PWN and elaborate on what can be learned about the particle acceleration from the dynamical structures called GwispsG observed in the Crab nebula. We also discuss recent observational and theoretical results of gamma-ray flares and the inner knot of the Crab nebula, which had been proposed as the emission site of the flares. We extend the discussion to GeV flares from binary systems in which the pulsar wind interacts with the stellar wind from a companion star. The chapter concludes with a discussion of solved and unsolved problems posed by PWN

    Air pollution and children's asthma-related emergency hospital visits in southeastern France

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    International audienceChildren's asthma is multifactorial. Environmental factors like air pollution exposure, meteorological conditions, allergens, and viral infections are strongly implicated. However, place of residence has rarely been investigated in connection with these factors. The primary aim of our study was to measure the impact of particulate matter (PM), assessed close to the children's homes, on asthma-related pediatric emergency hospital visits within the Bouches-du-Rhône area in 2013. In a nested case-control study on 3- to 18-year-old children, each control was randomly matched on the emergency room visit day, regardless of hospital. Each asthmatic child was compared to 15 controls. PM10 and PM2.5, meteorological conditions, pollens, and viral data were linked to ZIP code and analyzed by purpose of emergency visit. A total of 68,897 visits were recorded in children, 1182 concerning asthma. Short-term exposure to PM10 measured near children's homes was associated with excess risk of asthma emergency visits (adjusted odds ratio 1.02 (95% CI 1.01-1.04; p = 0.02)). Male gender, young age, and temperature were other risk factors. Conversely, wind speed was a protective factor.CONCLUSION:PM10 and certain meteorological conditions near children's homes increased the risk of emergency asthma-related hospital visits in 3- to 18-year-old children in Bouches-du-Rhône. What is Known: • A relationship between short-term exposure to air pollution and increase in emergency room visits or hospital admissions as a result of increased pollution levels has already been demonstrated. What is New: • This study confirms these results but took into account confounding factors (viral data, pollens, and meteorological conditions) and is based on estimated pollution levels assessed close to the children's homes, rather than those recorded at the hospital. • The study area, the Mediterranean, is favorable to creation of secondary pollutants in these sunny and dry seasons

    Inhalation therapy: Inhaled corticosteroids in ENT, development and technical challenges of powder inhalers, nebulisers synchronized with breathing and aerosol size distribution

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    International audienceThe working group on aerosol therapy (GAT) of the Société de Pneumologie de Langue Française (SPLF) has organized its third Aerosolstorming in 2012. During one single day, different aspects of inhaled therapies have been treated and are detailed in two articles, this one being the second. This text deals with the indications of inhaled corticosteroids in ENT, the development and technical challenges of powder inhalers, the advantages and disadvantages of each type of technologies to measure the particle sizes of inhaled treatments
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