Allergies respiratoires, pollens et polluants

National audienceFor 30 years, an increased incidence of respiratory allergy and asthma has been observed, particularly in children and young people living in urban areas of developed countries. A genetic origin is unlikely due to the rapidity of this increase and environmental factors (diet, lifestyle, exposure to xenobiotics...) should be involved. Epidemiological studies have shown that atmospheric pollutants may play a role. They could have an effect on the respiratory tract by inducing irritation, inflammation, airway hyperresponsiveness or enhancing respiratory allergies (adjuvant effect) or they could have an effect on the aeroallergens, in particular the pollens. Experimental studies have shown that pollen exposure to pollutants induce enhanced deformation or fracture of the external envelope linking to an enhanced liberation of intracytoplasmic allergenic granules and induce also a qualitative and quantitative modification of allergens. However, few experimental studies have shown that pollutant-exposed pollens are more allergenic that "clean" pollens. One important point to consider is the enhanced granule liberation by exposed pollens. Due to the small size of the granules, the allergen bioavailability may increase, leading to higher incidence of respiratory allergies.Depuis 30 ans, une incidence accrue des allergies respiratoires est observée, notamment chez les enfants et les adolescents vivant dans les zones urbaines des pays industrialisés. Il est admis que cette augmentation est trop rapide pour être liée à des facteurs génétiques et que d'autres facteurs, notamment environnementaux (alimentation, mode de vie, contact avec des xénobiotiques...) sont impliqués. Les études épidémiologiques montrent que les polluants de l'air en particulier semblent jouer un rôle important dans l'incidence des allergies. Ils peuvent agir soit par action au niveau du système respiratoire, en provoquant une irritation, une inflammation, une augmentation de l'hyperréactivité bronchique non spécifique ou en potentialisant une réponse allergique pré-existante (effet adjuvant), soit par action au niveau des aéroallergènes, dont les pollens représentent la majeure partie. Les principaux effets observés expérimentalement sont une augmentation des déformations et fractures de l'enveloppe externe conduisant à une libération accrue de granules intracytoplasmiques, eux-mêmes allergisants et une modification quantitative et qualitative des allergènes. Peu de travaux ont toutefois clairement mis en évidence une augmentation du potentiel allergisant des pollens après exposition aux polluants. Une piste à explorer reste la libération plus importante des granules intrapolliniques qui, de part leur petite taille, pourraient augmenter la biodisponibilité des allergènes et donc la fréquence et la gravité des allergies respiratoires

M3 money demand and excess liquidity in the euro area

Recent empirical studies have found evidence of unstable long run money demand functions if recent data are used. If the link between money balances and the macroeconomy is fragile, the rationale of monetary aggregates in the ECB strategy has to be doubted. In contrast we present a ``stable'' long run money demand relationship for M3 for the period 1983-2006. To obtain the result, the short run homogeneity restriction between money and prices is relaxed and a break in the income elasticity of money demand after 2001 is taken into account. Measures of excess liquidity do not show significant inflation pressures.The final publication is available at Springer via http://dx.doi.org/10.1007/s11127-010-9679-5. This publication was produced as part of the FINESS project, funded by the European Commission through the 7th Framework Programme under contract no. 217266 (http://www.finess-web.eu/)

Zeitabhaengige Konsistenzaenderungen bei zementgebundenen Moertelmischungen

Available from TIB Hannover: DW 1388 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

The logic of propagation strategies:Axiomatizing a fragment of organizational ecology in first-order logic

As a part of a larger effort to apply formal logic to organization science, we axiomatize the theory of propagation strategies (life history strategies) of Organization Ecology. We provide an axiomatic system in first-order logic that derives the theory's predictions as theorems from a set of underlying assumptions. First-order logic is widely seen as a standard language for the formalization of scientific theories; it couples considerable expressive power with acceptable computational properties. Our axiomatization increases the understanding on the scope and the limits of Organization Ecology, and yields a consistent theory of propagation strategies with a sound explanatory structure