ÉTUDE EN LIGNE SUR ISOCÈLE DE LA DÉSINTÉGRATION 186Tl → 186Hg

L'étude de la décroissance 186Tl → 186Hg a été entreprise à l'aide du séparateur en ligne Isocèle. Les niveaux 0+2 et 2+2 sont proposés à très basse énergie. Un schéma de niveaux partiel est discuté dans le cadre des modèles existants

Ice Cores from the St. Elias Mountains, Yukon, Canada: Their Significance for Climate, Atmospheric Composition and Volcanism in the North Pacific Region

A major achievement in research supported by the Kluane Lake Research Station was the recovery, in 2001 –02, of a suite of cores from the icefields of the central St. Elias Mountains, Yukon, by teams of researchers from Canada, the United States, and Japan. This project led to the development of parallel, long (103 – 104 year) ice-core records of climate and atmospheric change over an altitudinal range of more than 2 km, from the Eclipse Icefield (3017 m) to the ice-covered plateau of Mt. Logan (5340 m). These efforts built on earlier work recovering single ice cores in this region. Comparison of these records has allowed for variations in climate and atmospheric composition to be linked with changes in the vertical structure and dynamics of the North Pacific atmosphere, providing a unique perspective on these changes over the Holocene. Owing to their privileged location, cores from the St. Elias Icefields also contain a remarkably detailed record of aerosols from various sources around or across the North Pacific. In this paper we review major scientific findings from the study of St. Elias Mountain ice cores, focusing on five main themes: (1) The record of stable water isotopes (δ18O, δD), which has unique characteristics that differ from those of Greenland, other Arctic ice cores, and even among sites in the St. Elias; (2) the snow accumulation history; (3) the record of pollen, biomass burning aerosol, and desert dust deposition; (4) the record of long-range air pollutant deposition (sulphate and lead); and (5) the record of paleo-volcanism. Our discussion draws on studies published since 2000, but based on older ice cores from the St. Elias Mountains obtained in 1980 and 1996

The Effects of Flowline Length Evolution on Chemistry-Delta O-18 Profiles from Penny Ice Cap, Baffin Island, Canada

The isotopic and chemical signatures for ice-age and Holocene ice from Summit, Greenland and Penny Ice Cap, Baffin Island, Canada, arc compared. The usual pattern of low delta(18)O, high Ca2+ and high Cl- is presented in the Summit records, but Penny Ice Cap has lower than present Cl- in its ice-age ice. A simple extension of the Hansson model (Hansson, 1994) is developed and used to simulate these signatures. The low ice-age Cl- from Penny Ice Cap is explained by having the ice-age ice originating many thousands of km inland near the centre of the Laurentide ice sheet and much further from the marine sources. Summit\u27s flowlines all start close to the present site. The Penny Ice Cap early-Holocene delta(18)O\u27s had to be corrected to offset the Laurentide meltwater distortion. The analysis suggests that presently the Summit and Penny Ice Cap marine impurity originates about,500 km away, and that presently Penny Ice Cap receives a significant amount of local continental impurity

Ice Cores from the St. Elias Mountains, Yukon, Canada: Their Significance for Climate, Atmospheric Composition and Volcanism in the North Pacific Region

A major achievement in research supported by the Kluane Lake Research Station was the recovery, in 2001 –02, of a suite of cores from the icefields of the central St. Elias Mountains, Yukon, by teams of researchers from Canada, the United States, and Japan. This project led to the development of parallel, long (103 – 104 year) ice-core records of climate and atmospheric change over an altitudinal range of more than 2 km, from the Eclipse Icefield (3017 m) to the ice-covered plateau of Mt. Logan (5340 m). These efforts built on earlier work recovering single ice cores in this region. Comparison of these records has allowed for variations in climate and atmospheric composition to be linked with changes in the vertical structure and dynamics of the North Pacific atmosphere, providing a unique perspective on these changes over the Holocene. Owing to their privileged location, cores from the St. Elias Icefields also contain a remarkably detailed record of aerosols from various sources around or across the North Pacific. In this paper we review major scientific findings from the study of St. Elias Mountain ice cores, focusing on five main themes: (1) The record of stable water isotopes (δ18O, δD), which has unique characteristics that differ from those of Greenland, other Arctic ice cores, and even among sites in the St. Elias; (2) the snow accumulation history; (3) the record of pollen, biomass burning aerosol, and desert dust deposition; (4) the record of long-range air pollutant deposition (sulphate and lead); and (5) the record of paleo-volcanism. Our discussion draws on studies published since 2000, but based on older ice cores from the St. Elias Mountains obtained in 1980 and 1996

Variability and change in the Canadian cryosphere

Abstract During the International Polar Year (IPY), comprehensive observational research programs were undertaken to increase our understanding of the Canadian polar cryosphere response to a changing climate. Cryospheric components considered were snow, permafrost, sea ice, freshwater ice, glaciers and ice shelves. Enhancement of conventional observing systems and retrieval algorithms for satellite measurements facilitated development of a snapshot of current cryospheric conditions, providing a baseline against which future change can be assessed. Key findings include: 1. surface air temperatures across the Canadian Arctic exhibit a warming trend in all seasons over the past 40 years. A consistent pan-cryospheric response to these warming temperatures is evident through the analysis of multi-decadal datasets; 2. in recent years (including the IPY period) a higher rate of change was observed compared to previous decades including warming permafrost, reduction in snow cover extent and duration, reduction in summer sea ice extent, increased mass loss from glaciers, and thinning and break-up of the remaining Canadian ice shelves. These changes illustrate both a reduction in the spatial extent and mass of the cryosphere and an increase in the temporal persistence of melt related parameters. The observed changes in the cryosphere have important implications for human activity including the close ties of northerners to the land, access to northern regions for natural resource development, and the integrity of northern infrastructure

Periodontal Conditions and Pathogens Associated with Pre-Eclampsia: A Scoping Review

Background: Pre-eclampsia, the second most frequent direct source of maternal mortality, is a multisystem gestational disorder characterized by proteinuria and maternal hypertension after the 20th gestational week. Although the causes of pre-eclampsia are still discussed, research has suggested that the placenta has a central place in the pathogenesis of this disease. Moreover, current surveys indicated that periodontal disorders observed during the pregnancy and more particularly, periodontal pathogens could be link to the risk of pre-eclampsia. Objectives: This article aims to review recent studies focusing on periodontal conditions and pathogens associated with pre-eclampsia. Methods: The process followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews guidelines. Results: Metabolic conditions, immunological changes, fluctuating progesterone and estrogen levels of the pregnant woman induce a dysbiosis of the oral microbiota and contribute to increase inflammation of periodontal tissues. Periodontal pathogens could diffuse through the bloodstream inducing a placenta inflammatory response as well as inflammatory molecules produced in response to periodontopathogens could migrate through the bloodstream leading to a placenta inflammatory response. Also, periodontopathogens can colonize the vaginal microbiota through the gastrointestinal tract or during oro-genital contacts. Conclusion: A cumulative bi-directional relationship between periodontal conditions, pathogens and the pre-eclampsia exists

ÉTUDE EN LIGNE SUR ISOCÈLE DE LA DÉSINTÉGRATION 186Tl → 186Hg

L'étude de la décroissance 186Tl → 186Hg a été entreprise à l'aide du séparateur en ligne Isocèle. Les niveaux 0+2 et 2+2 sont proposés à très basse énergie. Un schéma de niveaux partiel est discuté dans le cadre des modèles existants.We have studied the 186Tl → 186Hg decay by means of the Isocele on-line isotope separator. The 0+2 and 2+2 levels are proposed at a low excitation energy. A partial level scheme is being discussed in the framework of available models

Microencapsulation of rifampicin for the prevention of endophthalmitis: In vitro release studies and antibacterial assessment

International audienceRifampicin encapsulated microparticles were designed for intraocular injection after cataract surgery to prevent postoperative endophthalmitis. Microparticles were formulated by emulsification diffusion method using poly(lactic acid-co-glycolic acid) (PLGA) as polymer in order to propose a new form of rifampicin that overcome its limitations in intraocular delivery. Depending on processing formulation, different types of microparticles were prepared, characterized and evaluated by in vitro release studies. Two types of microparticles were selected to get a burst release of rifampicin, to reach minimal inhibitory concentrations to inhibit 90% of Staphylococcus epidermidis mainly involved in postoperative endophthalmitis, combined with a sustained release to maintain rifampicin concentration over 24 h. The antibacterial activity and antiadhesive property on intraocular lenses were evaluated on S. epidermidis. Microparticles, with a rapid rifampicin release profile, showed an effect towards bacteria development similar to free rifampicin over 48 h. However, slow-release profile microparticles exhibited a similar antibacterial effect during the first 24 h, and were able to destroy all the S epidermidis in the medium after 30 h. The association of the two formulations allowed obtaining interesting antibacterial profile. Moreover, rifampicin-loaded microparticles have shown a very efficient anti-adherent effect of S. epidermidis on intraocular lenses at 24 h. These results propose rifampicin microparticles as suitable for antibioprophylaxis of the postoperative endophthalmitis. (C) 2016 Elsevier B.V. All rights reserved