Tracers of physical and biogeochemical processes, past changes and ongoing anthropogenic impacts: the 43rd International Liege Colloquium on Ocean Dynamics, Liege, Belgium, May 2-6, 2011

The 43rd International Liege Colloquium on Ocean Dynamics (http://modb.oce.ulg.ac.be/colloquium/) gathered a hundred scientists from around the world to discuss new developments and insights related to tracers and proxies (from temperature and salinity to gases and isotopes) with a particular attention on the use of Trace Elements and Isotopes (TEI) as tracers. The colloquium was organized in connection with the Geotraces program (an ongoing international study of the global marine biogeochemical cycles of trace elements and their isotopes, http://www.geotraces.org/) and was the occasion to present the wealth of data collected during large oceanographic expeditions that occurred in connection with the International Polar year. In this framework, particular emphasis was given to the BONUS-GoodHope project, a multi-disciplinary oceanographic cruise that coupled full-depth ocean and atmosphere physical and biogeochemical observations, including trace metals and isotopes (Speich et al. 2013; Speich et al. 2008). The special issue presents a collection of papers dealing with these different thematics

Modeling the Nd isotopic composition in the North Atlantic basin using an eddy-permitting model

International audienceBoundary Exchange (BE – exchange of elementsbetween continental margins and the open ocean) hasbeen emphasized as a key process in the oceanic cycle ofneodymium (Nd) (Lacan and Jeandel, 2005a). Here, we usea regional eddy-permitting resolution Ocean General CirculationModel (1/4) of the North Atlantic basin to simulatethe distribution of the Nd isotopic composition, consideringBE as the only source. Results show good agreementwith the data, confirming previous results obtained using thesame parameterization of the source in a coarse resolutionglobal model (Arsouze et al., 2007), and therefore the majorcontrol played by the BE processes in the Nd cycle onthe regional scale. We quantified the exchange rate of theBE, and found that the time needed for the continental marginsto significantly imprint the chemical composition of thesurrounding seawater (further referred as characteristic exchangetime) is of the order of 0.2 years. However, thetimescale of the BE may be subject to large variations as avery short exchange time (a few days) is needed to reproducethe highly negative values of surface waters in the LabradorSea, whereas a longer one (up to 0.5 years) is required tosimulate the radiogenic influence of basaltic margins and distinguishthe negative isotopic signatures of North AtlanticDeep Water from the more radiogenic southern origin watermasses. This likely represents geographical variations inerosion fluxes and the subsequent particle load onto the continentalmargins. Although the parameterization of the BEis the same in both configurations of the model, the characteristicexchange time in the eddy-permitting configuration issignificantly lower than the previous evaluations using a lowresolution configuration (6 months to 10 years), but howeverin agreement with the available seawater Nd isotope data.This results highlights the importance of the model dynamicsin simulating the BE proces

A modeling sensitivity study of the influence of the Atlantic meridional overturning circulation on neodymium isotopic composition at the Last Glacial Maximum

Using a simple parameterisation that resolves the first order global Nd isotopic composition (hereafter expressed as ε<sub>Nd</sub> in an Ocean Global Circulation Model, we have tested the impact of different circulation scenarios on the ε<sub>Nd</sub> in the Atlantic for the Last Glacial Maximum (LGM), relative to a modern control run. Three different LGM freshwater forcing experiments are performed to test for variability in the ε<sub>Nd</sub> oceanic distribution as a function of ocean circulation. Highly distinct representations of the ocean circulation are generated in the three simulations, which drive significant differences in ε<sub>Nd</sub>, particularly in deep waters of the western part of the basin. However, at the LGM, the Atlantic is more radiogenic than in the modern control run, particularly in the Labrador basin and in the Southern Ocean. A fourth experiment shows that changes in Nd sources and bathymetry drive a shift in the ε<sub>Nd</sub> signature of the basin that is sufficient to explain the changes in the ε<sub>Nd</sub> signature of the northern end-member (NADW or GNAIW glacial equivalent) in our LGM simulations. All three of our LGM circulation scenarios show good agreement with the existing intermediate depth ε<sub>Nd</sub> paleo-data. This study cannot indicate the likelihood of a given LGM oceanic circulation scenario, even if simulations with a prominent water mass of southern origin provide the most conclusive results. Instead, our modeling results highlight the need for more data from deep and bottom waters from western Atlantic, where the ε<sub>Nd</sub> change in the three LGM scenarios is the most important (up to 3 ε<sub>Nd</sub>. This would also aid more precise conclusions concerning the evolution of the northern end-member ε<sub>Nd</sub> signature, and thus the potential use of ε<sub>Nd</sub> as a tracer of past oceanic circulation

Mesure du champ de déplacement transverse par voie optique appliquée au thermoformage du verre

L'objectif de cette étude est de modéliser le comportement thermomécanique du verre au cours d'un procédé complet de thermoformage (montée en température, palier de travail, refroidissement). Le verre étant absorbant, émissif et non-diffusant, la prise en compte du rayonnement dans la modélisation du transfert de chaleur s'avère être indispensable.Après avoir présenté la problématique associée à ce projet, nous décrirons le banc expérimental développé au sein du laboratoire ; il devrait permettre de valider expérimentalement les résultats numériques issus de notre modélisation. Ce banc se compose d'un four de thermoformage adapté et couplé à un système optique de mesures de champ de déplacement et de température de la surface supérieure de la plaque de verre. Le dispositif et la méthode employés pour mesurer le déplacement, basés sur l'utilisation de la lumière structurée, seront au centre de cette présentation

Early Effect Markers and Exposure Determinants of Metalworking Fluids Among Metal Industry Workers: Protocol for a Field Study.

Exposure to aerosols from metalworking fluids (MWF) has previously been related to a series of adverse health outcomes (eg, cancer, respiratory diseases). Our present epidemiological study focuses on occupational exposures to MWF and a panel of exposure and effect biomarkers. We hypothesize that these health outcomes are caused by particle exposure that generates oxidative stress, leading to airway inflammation and ultimately to chronic respiratory diseases. We aimed to assess whether MWF exposure, in particular as characterized by its oxidative potential, is associated with biomarkers of oxidative stress and inflammation as well as genotoxic effects. The ultimate goal is to develop exposure reduction strategies based on exposure determinants that best predict MWF-related health outcomes. The following relationships will be explored: (1) exposure determinants and measured exposure; (2) occupational exposure and preclinical and clinical effect markers; (3) exposure biomarkers and biomarkers of effect in both exhaled breath condensate and urine; and (4) biomarkers of effect, genotoxic effects and respiratory symptoms. At least 90 workers from France and Switzerland (30 controls, 30 exposed to straight MWF and 30 to aqueous MWF) were followed over three consecutive days after a nonexposed period of at least two days. The exposure assessment is based on MWF, metal, aldehyde, and ultrafine particle number concentrations, as well as the intrinsic oxidative potential of aerosols. Furthermore, exposure biomarkers such as metals, metabolites of polycyclic aromatic hydrocarbons and nitrosamine are measured in exhaled breath condensate and urine. Oxidative stress biomarkers (malondialdehyde, 8-isoprostane, 8-hydroxy-2'-deoxyguanosine, nitrates, and nitrites) and exhaled nitric oxide, an airway inflammation marker, are repeatedly measured in exhaled breath condensate and urine. Genotoxic effects are assessed using the buccal micronucleus cytome assay. The statistical analyses will include modelling exposure as a function of exposure determinants, modelling the evolution of the biomarkers of exposure and effect as a function of the measured exposure, and modelling respiratory symptoms and genotoxic effects as a function of the assessed long-term exposure. Data collection, which occurred from January 2018 until June 2019, included 20 companies. At the date of writing, the study included 100 subjects and 29 nonoccupationally exposed controls. This study is unique as it comprises human biological samples, questionnaires, and MWF exposure measurement. The biomarkers collected in our study are all noninvasive and are useful in monitoring MWF exposed workers. The aim is to develop preventative strategies based on exposure determinants related to health outcomes. DERR1-10.2196/13744

Methods for analyzing the concentration and speciation of major and trace elements in marine particles

Particles influence trace element and isotope (TEI) cycles through both their elemental composition and fate and their role on the partitioning of dissolved elements through scavenging and dissolution. Because of their complex compositions, a diverse suite of methods is required to analyze marine particles. Here we review some of the varied approaches used to study particle composition, speciation and fate. We focus on high throughput analytical methods that are useful for the international GEOTRACES program, and we also describe new spectroscopic techniques that are now being applied to study the spatial distribution and chemical speciation of TEIs in marine particles

Rapid cognitive decline, one-year institutional admission and one-year mortality: Analysis of the ability to predict and inter-tool agreement of four validated clinical frailty indexes in the safes cohort

Objectives: To evaluate the predictive ability of four clinical frailty indexes as regards one-year rapid cognitive decline (RCD — defined as the loss of at least 3 points on the MMSE score), and one-year institutional admission (IA) and mortality respectively; and to measure their agreement for identifying groups at risk of these severe outcomes. Design: One-year follow-up and multicentre study of old patients participating in the SAFEs cohort study. Setting: Nine university hospitals in France. Participants: 1,306 patients aged 75 or older (mean age 85±6 years; 65% female) hospitalized in medical divisions through an Emergency department. Measurements: Four frailty indexes (Winograd; Rockwood; Donini; and Schoevaerdts) reflecting the multidimensionality of the frailty concept, using an ordinal scoring system able to discriminate different grades of frailty, and constructed based on the accumulation of identified deficits after comprehensive geriatric assessment conducted during the first week of hospital stay, were used to categorize participants into three different grades of frailty: Gl — not frail; G2 — moderately frail; and G3 — severely frail. Comparisons between groups were performed using Fisher's exact test. Agreement between indexes was evaluated using Cohen's Kappa coefficient. Results: All patients were classified as frail by at least one of the four indexes. The Winograd and Rockwood indexes mainly classified subjects as G2 (85% and 96%), and the Donini and Schoevaerdts indexes mainly as G3 (71% and 67%). Among the SAFEs cohort population, 250, 1047 and 1,306 subjects were eligible for analyses of predictability for RCD, 1-year IA and 1-year mortality respectively. At 1 year, 84 subjects (34%) experienced RCD, 377 (36%) were admitted into an institutional setting, and 445 (34%) had died With the Rockwood index, all subjects who expenenced RCD were classified in G2; and in G2 and G3 when the Donini and Schoevaerdts indexes were used No significant difference was found between frailty grade and RCD, whereas frailty grade was significantly associated with an increased risk of IA and death, whatever the frailty index considered. Agreement between the different indexes of frailty was poor with Kappa coefficients ranging from −0.02 to 0.15. Conclusion: These findings confirm the poor clinimetric properties of these current indexes to measure frailty, underlining the fact that further work is needed to develop a better and more widely-accepted definition of frailty and therefore a better understanding of its pathophysiolog

Abnormal T-cell phenotype in episodic angioedema with hypereosinophilia (Gleich's syndrome): frequency, clinical implication and prognosis

BACKGROUND: Episodic Angioedema with eosinophilia (EAE, Gleich\u27s syndrome) is a rare disorder consisting of recurrent episodes of angioedema, hypereosinophilia and frequent elevated serum Immunoglobin M. METHODS: We conducted a retrospective multicenter nationwide study regarding the clinical spectrum and therapeutic management of patients with EAE in France. RESULTS: Thirty patients were included with a median age at diagnosis of 41 years [5-84]. The median duration of each crisis was 5.5 days [1-90] with swelling affecting mainly the face and the upper limbs. Total serum IgM levels were increased in 20 patients (67%). Abnormal T-cell immunophenotypes were detected in 12 patients (40%) among which 5 (17%) showed evidence of clonal TCR γ gene rearrangement. Median follow-up duration was 53 months [31-99]. The presence of an abnormal T-cell population was the sole factor associated with a shorter time to flare (hazard ratio 4.15 [CI 95% 1.18-14.66; p=0.02). At last follow-up, 3 patients (10%) were able to withdraw all treatments and 11 (37%) were in clinical and biological remission with less than 10 mg of daily prednisone. CONCLUSION: EAE is a heterogeneous condition that encompasses several disease forms. Although patients usually respond well to glucocorticoids, those with evidence of abnormal T-cell phenotype have a shorter time to flare

The GEOTRACES Intermediate Data Product 2017

The GEOTRACES Intermediate Data Product 2017 (IDP2017) is the second publicly available data product of the international GEOTRACES programme, and contains data measured and quality controlled before the end of 2016. The IDP2017 includes data from the Atlantic, Pacific, Arctic, Southern and Indian oceans, with about twice the data volume of the previous IDP2014. For the first time, the IDP2017 contains data for a large suite of biogeochemical parameters as well as aerosol and rain data characterising atmospheric trace element and isotope (TEI) sources. The TEI data in the IDP2017 are quality controlled by careful assessment of intercalibration results and multi-laboratory data comparisons at crossover stations. The IDP2017 consists of two parts: (1) a compilation of digital data for more than 450 TEIs as well as standard hydrographic parameters, and (2) the eGEOTRACES Electronic Atlas providing an on-line atlas that includes more than 590 section plots and 130 animated 3D scenes. The digital data are provided in several formats, including ASCII, Excel spreadsheet, netCDF, and Ocean Data View collection. Users can download the full data packages or make their own custom selections with a new on-line data extraction service. In addition to the actual data values, the IDP2017 also contains data quality flags and 1-σ data error values where available. Quality flags and error values are useful for data filtering and for statistical analysis. Metadata about data originators, analytical methods and original publications related to the data are linked in an easily accessible way. The eGEOTRACES Electronic Atlas is the visual representation of the IDP2017 as section plots and rotating 3D scenes. The basin-wide 3D scenes combine data from many cruises and provide quick overviews of large-scale tracer distributions. These 3D scenes provide geographical and bathymetric context that is crucial for the interpretation and assessment of tracer plumes near ocean margins or along ridges. The IDP2017 is the result of a truly international effort involving 326 researchers from 25 countries. This publication provides the critical reference for unpublished data, as well as for studies that make use of a large cross-section of data from the IDP2017. This article is part of a special issue entitled: Conway GEOTRACES - edited by Tim M. Conway, Tristan Horner, Yves Plancherel, and Aridane G. González.We gratefully acknowledge financial support by the Scientific Committee on Oceanic Research (SCOR) through grants from the U.S. National Science Foundation, including grants OCE-0608600, OCE0938349, OCE-1243377, and OCE-1546580. Financial support was also provided by the UK Natural Environment Research Council (NERC), the Ministry of Earth Science of India, the Centre National de Recherche Scientifique, l'Université Paul Sabatier de Toulouse, the Observatoire Midi-Pyrénées Toulouse, the Universitat Autònoma de Barcelona, the Kiel Excellence Cluster The Future Ocean, the Swedish Museum of Natural History, The University of Tokyo, The University of British Columbia, The Royal Netherlands Institute for Sea Research, the GEOMAR-Helmholtz Centre for Ocean Research Kiel, and the Alfred Wegener Institut