Diffusion of HTO, Br-, I-, Cs+, Sr-85(2+) and Co-60(2+) in a clay formation: Results and modelling from an in situ experiment in Opalinus Clay

The migration of radioactive and chemical contaminants in clay materials and argillaceous host rocks is characterised by diffusion and retention processes. Valuable information on such processes can be gained by combining diffusion studies at laboratory scale with field migration tests. In this work, the outcome of a multi-tracer in situ migration test performed in the Opalinus Clay formation in the Mont Terri underground rock laboratory (Switzerland) is presented. Thus, 1.16 x 10(5) Bq/L of HTO, 3.96 x 10(3) Bq/L of Sr-85, 6.29 x 10(2) Bq/L of Co-60, 2.01 x 10(-3) mol/L Cs, 9.10 x 10(-4) mol/L I and 1.04 x 10(-3) mol/L Br were injected into the borehole. The decrease of the radioisotope concentrations in the borehole was monitored using in situ gamma-spectrometry. The other tracers were analyzed with state-of-the-art laboratory procedures after sampling of small water aliquots from the reservoir. The diffusion experiment was carried out over a period of one year after which the interval section was overcored and analyzed. Based on the experimental data from the tracer evolution in the borehole and the tracer profiles in the rock, the diffusion of tracers was modelled with the numerical code CRUNCH. The results obtained for HTO (H-3), I- and Br- confirm previous lab and in situ diffusion data. Anionic fluxes into the formation were smaller compared to HTO because of anion exclusion effects. The migration of the cations Sr-85(2+), Cs+ and Co-60(2+) was found to be governed by both diffusion and sorption processes. For Sr-85(2+), the slightly higher diffusivity relative to HTO and the low sorption value are consistent with laboratory diffusion measurements on small-scale samples. In the case of Cs+, the numerically deduced high diffusivity and the Freundlich-type sorption behaviour is also supported by ongoing laboratory data. For Co, no laboratory diffusion data were yet available for comparison; however, the modelled data suggests that Co-60(2+) sorption was weaker than would be expected from available batch sorption data. Overall, the results demonstrate the feasibility of the experimental setup for obtaining high-quality diffusion data for conservative and sorbing tracers. (C) 2007 Elsevier Ltd. All rights reserved.

An optimized multi-proxy, multi-site Antarctic ice and gas orbital chronology (AICC2012): 120--800 ka

An accurate and coherent chronological framework is essential for the interpretation of climatic and environmental records obtained from deep polar ice cores. Until now, one common ice core age scale had been developed based on an inverse dating method (Datice), combining glaciological modelling with absolute and stratigraphic markers between 4 ice cores covering the last 50 ka (thousands of years before present) (Lemieux-Dudon et al., 2010). In this paper, together with the companion paper of Veres et al. (2013), we present an extension of this work back to 800 ka for the NGRIP, TALDICE, EDML, Vostok and EDC ice cores using an improved version of the Datice tool. The AICC2012 (Antarctic Ice Core Chronology 2012) chronology includes numerous new gas and ice stratigraphic links as well as improved evaluation of background and associated variance scenarios. This paper concentrates on the long timescales between 120–800 ka. In this framework, new measurements of δ18Oatm over Marine Isotope Stage (MIS) 11–12 on EDC and a complete δ18Oatm record of the TALDICE ice cores permit us to derive additional orbital gas age constraints. The coherency of the different orbitally deduced ages (from δ18Oatm, δO2/N2 and air content) has been verified before implementation in AICC2012. The new chronology is now independent of other archives and shows only small differences, most of the time within the original uncertainty range calculated by Datice, when compared with the previous ice core reference age scale EDC3, the Dome F chronology, or using a comparison between speleothems and methane. For instance, the largest deviation between AICC2012 and EDC3 (5.4 ka) is obtained around MIS 12. Despite significant modifications of the chronological constraints around MIS 5, now independent of speleothem records in AICC2012, the date of Termination II is very close to the EDC3 one.

„Mönch und Jungfrau“ Eine Diskurs- und Dispositivanalyse zur medialen Konstruktion abweichender Geschlechtlichkeit der südafrikanischen 800 Meterläuferin Caster Semenya

Einleitung Die mediale Debatte um das Geschlecht der südafrikanischen 800 Meterläuferin Casta Semenya entbrannte in dem Moment, in dem die Athletin im Finale der Leichtathletik Weltmeisterschaften in Berlin am 19. August 2009 als erste über die Ziellinie lief. Ihr Sieg war begleitet von vielseitig öffentlich geäusserten Zweifeln an ihrer Zuordnung zur weiblichen Geschlechterkategorie. und damit ihrem Recht, mit Frauen in sportlichen Wettstreit zu treten. Die International Association of Athletics Federations (IAFF) forderte für die Anerkennung der gewonnen Goldmedaille einen sogenannten Geschlechtertest (gender verification test). Theorie, Fragestellung und Methode Aus sozialkonstruktivistischer (Berger & Luckmann) poststrukturalistischer (Foucault) sowie gender und postkolonialer (Butler; Hall; Spivak) Perspektive, wird durch den diskursanalytischen Ansatz (Jäger) aufgezeigt, wie eine mögliche Intersexualität der nicht weissen, südafrikanischen Läufer_in Casta Semenya im hegemonialen Diskurs deutsch-schweizerischer Printmedien verhandelt wurde. Eine zentrale Fragestellung ist, wie der Körper als deviant konstruiert wurde und welche Diskursverschränkungen eine Pluralisierung und Diversifizierung hätten nahelegen können, jedoch zu der gänzlichen Infragestellung des als abweichend rezipierten Körpers und seiner legitimen Existenz im leistungssportlichen Kontext führte. Im Zusammenhang mit der Fragestellung werden empirisch Befunde zu intersektioneller Überlagerungen der Differenzkategorien, Geschlecht, Ethnizität und Sexualität vorgestellt. Ergebnisse und Diskussion In der abschliessenden Diskussion wird durch eine theoriegeleitete Kontextualisierung aufgezeigt, wie die verschränkten Kategorien Geschlecht, Ethnizität und Sexualität den nicht weissen, Körper als spektakulär Anderen konstituierten (Gilman). Am Beispiel des vielfältig verschränkten Diskurses zu Casta Semenya wird in Rückbezug auf postkoloniale Theorien gezeigt, wie an hegemonialen westlichen Normen eines weissen weiblichen Sportkörpers das „Othering“ des vermeintlich devianten Körper vollzogen wird (Coleman-Bell; Hall). Deutlich wird am Ende, dass nicht nur das binäre, geschlechterdifferenzierende Modell des Sports im Diskurs rekonsolidiert wurde, sondern vor allem auch die Postulate der Natürlichkeit, Fairness und Chancengleichheit des Leistungssports.

„Mönch und Jungfrau“. Eine Diskurs- und Dispositivanalyse zur medialen Konstruktion abweichender Geschlechtlichkeit der südafrikanischen 800 Meterläuferin Caster Semenya

Einleitung: Die mediale Debatte um das Geschlecht der südafrikanischen 800 Meterläuferin Casta Semenya entbrannte in dem Moment, in dem die Athletin im Finale der Leichtathletik Weltmeisterschaften in Berlin am 19. August 2009 als erste über die Ziellinie lief. Ihr Sieg war begleitet von vielseitig öffentlich geäusserten Zweifeln an ihrer Zuordnung zur weiblichen Geschlechterkategorie. und damit ihrem Recht, mit Frauen in sportlichen Wettstreit zu treten. Die International Association of Athletics Federations (IAFF) forderte für die Anerkennung der gewonnen Goldmedaille einen sogenannten Geschlechtertest (gender verification test). Theorie, Fragestellung und Methode Aus sozialkonstruktivistischer (Berger & Luckmann) poststrukturalistischer (Foucault) sowie gender und postkolonialer (Butler; Hall; Spivak) Perspektive, wird durch den diskursanalytischen Ansatz (Jäger) aufgezeigt, wie eine mögliche Intersexualität der nicht weissen, südafrikanischen Läufer_in Casta Semenya im hegemonialen Diskurs deutsch-schweizerischer Printmedien verhandelt wurde. Eine zentrale Fragestellung ist, wie der Körper als deviant konstruiert wurde und welche Diskursverschränkungen eine Pluralisierung und Diversifizierung hätten nahelegen können, jedoch zu der gänzlichen Infragestellung des als abweichend rezipierten Körpers und seiner legitimen Existenz im leistungssportlichen Kontext führte. Im Zusammenhang mit der Fragestellung werden empirisch Befunde zu intersektioneller Überlagerungen der Differenzkategorien, Geschlecht, Ethnizität und Sexualität vorgestellt. Ergebnisse und Diskussion In der abschliessenden Diskussion wird durch eine theoriegeleitete Kontextualisierung aufgezeigt, wie die verschränkten Kategorien Geschlecht, Ethnizität und Sexualität den nicht weissen, Körper als spektakulär Anderen konstituierten (Gilman). Am Beispiel des vielfältig verschränkten Diskurses zu Casta Semenya wird in Rückbezug auf postkoloniale Theorien gezeigt, wie an hegemonialen westlichen Normen eines weissen weiblichen Sportkörpers das „Othering“ des vermeintlich devianten Körper vollzogen wird (Coleman-Bell; Hall). Deutlich wird am Ende, dass nicht nur das binäre, geschlechterdifferenzierende Modell des Sports im Diskurs rekonsolidiert wurde, sondern vor allem auch die Postulate der Natürlichkeit, Fairness und Chancengleichheit des Leistungssports.

Corticosteroid treatment for community-acquired pneumonia--the STEP trial: study protocol for a randomized controlled trial

BACKGROUND Community-acquired pneumonia (CAP) is the third-leading infectious cause of death worldwide. The standard treatment of CAP has not changed for the past fifty years and its mortality and morbidity remain high despite adequate antimicrobial treatment. Systemic corticosteroids have anti-inflammatory effects and are therefore discussed as adjunct treatment for CAP. Available studies show controversial results, and the question about benefits and harms of adjunct corticosteroid therapy has not been conclusively resolved, particularly in the non-critical care setting. METHODS/DESIGN This randomized multicenter study compares a treatment with 7 days of prednisone 50 mg with placebo in adult patients hospitalized with CAP independent of severity. Patients are screened and enrolled within the first 36 hours of presentation after written informed consent is obtained. The primary endpoint will be time to clinical stability, which is assessed every 12 hours during hospitalization. Secondary endpoints will be, among others, all-cause mortality within 30 and 180 days, ICU stay, duration of antibiotic treatment, disease activity scores, side effects and complications, value of adrenal function testing and prognostic hormonal and inflammatory biomarkers to predict outcome and treatment response to corticosteroids. Eight hundred included patients will provide an 85% power for the intention-to-treat analysis of the primary endpoint. DISCUSSION This largest to date double-blind placebo-controlled multicenter trial investigates the effect of adjunct glucocorticoids in 800 patients with CAP requiring hospitalization. It aims to give conclusive answers about benefits and risks of corticosteroid treatment in CAP. The inclusion of less severe CAP patients will be expected to lead to a relatively low mortality rate and survival benefit might not be shown. However, our study has adequate power for the clinically relevant endpoint of clinical stability. Due to discontinuing glucocorticoids without tapering after seven days, we limit duration of glucocorticoid exposition, which may reduce possible side effects. TRIAL REGISTRATION 7 September 2009 on ClinicalTrials.gov: NCT00973154.

The mobility of Nb in rutile-saturated NaCl- and NaF-bearing aqueous fluids from 1-6.5 GPa and 300-800 °C

Rutile (TiO2) is an important host phase for high field strength elements (HFSE) such as Nb in metamorphic and subduction zone environments. The observed depletion of Nb in arc rocks is often explained by the hypothesis that rutile sequesters HFSE in the subducted slab and overlying sediment, and is chemically inert with respect to aqueous fluids evolved during prograde metamorphism in the forearc to subarc environment. However, field observations of exhumed terranes, and experimental studies, indicate that HFSE may be soluble in complex aqueous fluids at high pressure (i.e., >0.5 GPa) and moderate to high temperature (i.e., >300 degrees C). In this study, we investigated experimentally the mobility of Nb in NaCl- and NaF-bearing aqueous fluids in equilibrium with Nb-bearing rutile at pressure-temperature conditions applicable to fluid evolution in arc environments. Niobium concentrations in aqueous fluid at rutile saturation were measured directly by using a hydrothermal diamond-anvil cell (HDAC) and synchrotron X-ray fluorescence (SXRF) at 2.1 to 6.5 GPa and 300-500 degrees C, and indirectly by performing mass loss experiments in a piston-cylinder (PC) apparatus at similar to 1 GPa and 700-800 degrees C. The concentration of Nb in a 10 wt% NaCl aqueous fluid increases from 6 to 11 mu g/g as temperature increases from 300 to 500 degrees C, over a pressure range from 2.1 to 2.8 GPa, consistent with a positive temperature dependence. The concentration of Nb in a 20 wt% NaCl aqueous fluid varies from 55 to 150 mu g/g at 300 to 500 degrees C, over a pressure range from 1.8 to 6.4 GPa; however, there is no discernible temperature or pressure dependence. The Nb concentration in a 4 wt% NaF-bearing aqueous fluid increases from 180 to 910 mu g/g as temperature increases from 300 to 500 degrees C over the pressure range 2.1 to 6.5 GPa. The data for the F-bearing fluid indicate that the Nb content of the fluid exhibits a dependence on temperature between 300 and 500 degrees C at >= 2 GPa, but there is no observed dependence on pressure. Together, the data demonstrate that the hydrothermal mobility of Nb is strongly controlled by the composition of the fluid, consistent with published data for Ti. At all experimental conditions, however, the concentration of Nb in the fluid is always lower than coexisting rutile, consistent with a role for rutile in moderating the Nb budget of arc rocks.

Climatic change and contemporaneous land-use phases north and south of the Alps 2300 BC to 800 AD

Fluctuations in the Δ14C curve and subsequent gaps of archaeological findings at 800–650 and 400–100 BC in western and central Europe may indicate major climate-driven land-abandonment phases. To address this hypothesis radiocarbon-dated sediments from four lakes in Switzerland were studied palynologically. Pollen analysis indicates contemporaneous phases of forest clearances and of intensified land-use at 1450–1250 BC, 650–450 BC, 50 BC–100 AD and around 700 AD. These land-use expansions coincided with periods of warm climate as recorded by the Alpine dendroclimatic and Greenland oxygen isotope records. Our results suggest that harvest yields would have increased synchronously over wide areas of central and southern Europe during periods of warm and dry climate. Combined interpretation of palaeoecological and archaeological findings suggests that higher food production led to increased human populations. Positive long-term trends in pollen values of Cerealia and Plantago lanceolata indicate that technical innovations during the Bronze and Iron Age (e.g. metal ploughs, scythes, hay production, fertilising methods) gradually increased agricultural productivity. The successful adoption of yield-increasing advances cannot be explained by climatic determinism alone. Combined with archaeological evidence, our results suggest that despite considerable cycles of spatial and demographic reorganisation (repeated land abandonments and expansions, as well as large-scale migrations and population decreases), human societies were able to shift to lower subsistence levels without dramatic ruptures in material culture. However, our data imply that human societies were not able to compensate rapidly for harvest failures when climate deteriorated. Agriculture in marginal areas was abandoned, and spontaneous reforestations took place on abandoned land south and north of the Alps. Only when the climate changed again to drier and warmer conditions did a new wide-spread phase of forest clearances and field extensions occur, allowing the reoccupation of previously abandoned areas. Spatial distribution of cereal cultivation and growth requirements of Cerealia species suggest that increases in precipitation were far more decisive in driving crop failures over central and southern Europe than temperature decreases.