Search results for "Ozone"
showing 10 items of 300 documents
Global sea-to-air flux climatology for bromoform, dibromomethane and methyl iodide
2013
Volatile halogenated organic compounds containing bromine and iodine, which are naturally produced in the ocean, are involved in ozone depletion in both the troposphere and stratosphere. Three prominent compounds transporting large amounts of marine halogens into the atmosphere are bromoform (CHBr3), dibromomethane (CH2Br2) and methyl iodide (CH3I). The input of marine halogens to the stratosphere has been estimated from observations and modelling studies using low-resolution oceanic emission scenarios derived from top-down approaches. In order to improve emission inventory estimates, we calculate data-based high resolution global sea-to-air flux estimates of these compounds from surface ob…
Prévision et spatialisation des concentrations en ozone troposphérique en Bourgogne
2006
This PhD done in the Centre de Recherche de Climatologie, UMR 5210 CNRS of University of Burgundy has been supported by the Conseil Régional de Bourgogne, and the AASQA of Burgundy (Atmosf'Air). The ozone, a poison gas, is the core of this research because it is considered as one of the major worrying atmospheric pollutants in this region. We have conducted a study focused on hourly concentrations of measured ozone over several years for 12 stations. Their spatial and temporal variability are related to some features outside of the region (ground-level ozone, synoptic-scale conditions) and inside of the region (physical properties, land cover, meteorological features and precursor potential…
Apports des données Aladin dans le cadre d'une prévision de l'ozone troposphérique en Bourgogne
2003
Le CRC et les réseaux de surveillance de la qualité de l'air ATMOSF'air Bourgogne Centre-Nord et Sud élaborent un outil de prévision au lendemain de la pollution à l'ozone troposphérique. L'objectif est de prévoir les concentrations maximales quotidiennes à l'aide de modèles statistiques exploitables par les réseaux. Ces modèles considèrent des précurseurs de l'ozone, mesurés le jour où est effectuée la prévision, et les conditions météorologiques du jour pour lequel est effectuée la prévision. Une première étape fut d'étudier la prévisibilité de l'ozone à partir d'observations météorologiques ou « prévisions météorologiques parfaites ». Une seconde fut de réaliser de véritables prévisions.…
Analyse de la répartition spatiale des concentrations d'ozone en Bourgogne: résultats préliminaires
2005
International audience; Une campagne de mesures de l'ozone troposphérique par tubes à diffusion passifs a été effectuée en août 2000 sur toute la région Bourgogne afin d'essayer de mieux comprendre la répartition spatiale des concentrations à l'échelle d'une région. Les résultats ont montré, comme attendu, des concentrations en ozone diurne et nocturne différentes. À cette variabilité jour/nuit serait associée une superposition de signaux d'échelles spatiales et temporelles différentes. En première approximation, nous avons considéré les concentrations d'ozone mesurées sur la région comme la somme de plusieurs signaux de fréquences différentes : un signal « basse fréquence » — ou de fond — …
Des canaux Ioniques de la membrane plasmique lors de la mort cellulaire programmée induite par l’ozone chez A. thaliana
2011
Tropospheric ozone is a major secondary pollutant. In addition to its role in greenhouse effect gas, ozone is one of the most toxic air pollutants, and its pollution affects both human health and crop productivity. The work presented in this thesis concerns the role of ion channels in the plasma membrane in response to acute exposure to ozone and their interactions with signaling events leading to O3-induced PCD in A. Thaliana cultured cells. We have shown that cell death was genetically controlled and characterized by cell shrinkage similar to the mechanism of "Apoptosis Volume Decrease" (AVD) described in animal. This process is initially promoted by an early activation of a plasma membra…
La transition socio-écologique, une opportunité pour co-construire le futur de l'Europe
2015
International audience
New insights into the diversity dynamics of Triassic conodonts
2013
International audience; In this paper, we examine the diversity trends and the evolutionary patterns of Triassic conodonts through a newly powered large-scale data-set compiled directly from the primary literature. Paleodiversity dynamics analyses have been undertaken by working at the species level and using a system of time units based on biozone subdivisions for a fine temporal level resolution. The role of heterogeneous duration of taxa in diversity estimates has been evaluated through the probabilistic profiles. Results reveal three different stages in the diversity behaviour of Triassic conodonts from standing metrics delimited by two inflections at the mid-Anisian and mid-Carnian. Su…
A Revision of theniveaGroup of the Shore-Fly GenusDitrichophoraCresson (Diptera: Ephydridae)
2010
ABSTRACT Species of the nivea group (genus Ditrichophora Cresson) are revised. The group now includes four species of which one, D. gulkana (Alaska and Mongolia), is newly described. The group is now known to have a Holarctic distribution with two species, D. gulkana and D. nivea, being the first reported from the Nearctic Region. Another Asian species, D. brunnicosa, previously placed in Diclasiopa, is transferred to this group (genus Ditrichophora) and is also reported from Mongolia. To facilitate identification of these rare species, we have included diagnoses of the tribe, genus, and species group and have also provided an annotated key to Holarctic genera of the tribe Discocerinini and…
Le dimorphisme chez Perisphinctes (Properisphinctes) cf. bernensis de Loriol (Oxfordien inférieur, région de Cracovie, Pologne)
2004
Resume Une population d'ammonites rapportee a Perisphinctes (Properisphinctes) cf. bernensis de Loriol 1898, d'âge Oxfordien inferieur (zone a Mariae), a ete trouvee dans la region de Cracovie, dans le Sud de la Pologne. L'etude de ces formes a permis de montrer l'existence, au sein de cette espece, d'un dimorphisme microconque/macroconque, qui etait soupconne, mais non encore demontre avec certitude. Cette espece, connue en Europe uniquement par des individus incomplets, precise notre connaissance des perisphinctides de la base de l'Oxfordien inferieur. Pour citer cet article : R. Tarkowski, D. Marchand, C. R. Palevol 3 (2004).
OZONE THERAPY: MECHANISMS OF ACTION, RECENT LITERATURE AND NEWLY DISCOVERED BIOCHEMICAL PATHWAYS
2018
Ozone therapy is widely used in many countries since many years. Recently, the increasing widespread of this complementary therapy has been accomplished by an increased number of basic and clinic papers published on international journals. This lecture will deal on the first approach by a pharmacological point of view in the aim to characterize the mechanisms activated at sub-cellular level by ozone when used for medical and beauty application at low graded doses. The first theory was based upon the fact that the exposure to low, non-toxic, ozone concentrations could increase the efficacy of the endogenous antioxidant system by increasing the production or the activity of some enzymes exert…