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Within the framework of air quality studies at the megacity scale, highly time-resolved volatile organic compound (C2–C8) measurements were performed in downtown Paris (urban background sites) from January to November 2010. This unique dataset included non-methane hydrocarbons (NMHCs) and aromatic/oxygenated species (OVOCs) measured by a GC-FID (gas chromatograph with a flame ionization detector) and a PTR-MS (proton transfer reaction – mass spectrometer), respectively. This study presents the seasonal variability of atmospheric VOCs being monitored in the French megacity and their various associated emission sources. Clear seasonal and diurnal patterns differed from one VOC to another as the result of their different origins and the influence of environmental parameters (solar radiation, temperature). Source apportionment (SA) was comprehensively conducted using a multivariate mathematical receptor modeling. The United States Environmental Protection Agency's positive matrix factorization tool (US EPA, PMF) was used to apportion and quantify ambient VOC concentrations into six different sources. The modeled source profiles were identified from near-field observations (measurements from three distinct emission sources: inside a highway tunnel, at a fireplace and from a domestic gas flue, hence with a specific focus on road traffic, wood-burning activities and natural gas emissions) and hydrocarbon profiles reported in the literature. The reconstructed VOC sources were cross validated using independent tracers such as inorganic gases (NO, NO2, CO), black carbon (BC) and meteorological data (temperature). The largest contributors to the predicted VOC concentrations were traffic-related activities (including motor vehicle exhaust, 15 % of the total mass on the annual average, and evaporative sources, 10 %), with the remaining emissions from natural gas and background (23 %), solvent use (20 %), wood-burning (18 %) and a biogenic source (15 %). An important finding of this work is the significant contribution from wood-burning, especially in winter, where it could represent up to  ∼  50 % of the total mass of VOCs. Biogenic emissions also surprisingly contributed up to  ∼  30 % in summer (due to the dominating weight of OVOCs in this source). Finally, the mixed natural gas and background source exhibited a high contribution in spring (35 %, when continental air influences were observed) and in autumn (23 %, for home heating consumption).

Although practice guidelines recommend outpatient care for selected, haemodynamically stable patients with pulmonary embolism, most treatment is presently inpatient based. We aimed to assess non-inferiority of outpatient care compared with inpatient care. We undertook an open-label, randomised non-inferiority trial at 19 emergency departments in Switzerland, France, Belgium, and the USA. We randomly assigned patients with acute, symptomatic pulmonary embolism and a low risk of death (pulmonary embolism severity index risk classes I or II) with a computer-generated randomisation sequence (blocks of 2–4) in a 1:1 ratio to initial outpatient (ie, discharged from hospital ≤24 h after randomisation) or inpatient treatment with subcutaneous enoxaparin (≥5 days) followed by oral anticoagulation (≥90 days). The primary outcome was symptomatic, recurrent venous thromboembolism within 90 days; safety outcomes included major bleeding within 14 or 90 days and mortality within 90 days. We used a non-inferiority margin of 4% for a difference between inpatient and outpatient groups. We included all enrolled patients in the primary analysis, excluding those lost to follow-up. This trial is registered with ClinicalTrials.gov, number NCT00425542. Between February, 2007, and June, 2010, we enrolled 344 eligible patients. In the primary analysis, one (0·6%) of 171 outpatients developed recurrent venous thromboembolism within 90 days compared with none of 168 inpatients (95% upper confidence limit [UCL] 2·7%; p=0·011). Only one (0·6%) patient in each treatment group died within 90 days (95% UCL 2·1%; p=0·005), and two (1·2%) of 171 outpatients and no inpatients had major bleeding within 14 days (95% UCL 3·6%; p=0·031). By 90 days, three (1·8%) outpatients but no inpatients had developed major bleeding (95% UCL 4·5%; p=0·086). Mean length of stay was 0·5 days (SD 1·0) for outpatients and 3·9 days (SD 3·1) for inpatients. In selected low-risk patients with pulmonary embolism, outpatient care can safely and effectively be used in place of inpatient care. Swiss National Science Foundation, Programme Hospitalier de Recherche Clinique, and the US National Heart, Lung, and Blood Institute. Sanofi-Aventis provided free drug supply in the participating European centres.

Diagnosis of pulmonary embolism requires clinical probability assessment. Implicit assessment is accurate but is not standardized, and current prediction rules have shortcomings. To construct a simple score based entirely on clinical variables and independent from physicians' implicit judgment. Derivation and external validation of the score in 2 independent management studies on pulmonary embolism diagnosis. Emergency departments of 3 university hospitals in Europe. Consecutive patients admitted for clinically suspected pulmonary embolism. Collected data included demographic characteristics, risk factors, and clinical signs and symptoms suggestive of venous thromboembolism. The variables statistically significantly associated with pulmonary embolism in univariate analysis were included in a multivariate logistic regression model. Points were assigned according to the regression coefficients. The score was then externally validated in an independent cohort. The score comprised 8 variables (points): age older than 65 years (1 point), previous deep venous thrombosis or pulmonary embolism (3 points), surgery or fracture within 1 month (2 points), active malignant condition (2 points), unilateral lower limb pain (3 points), hemoptysis (2 points), heart rate of 75 to 94 beats/min (3 points) or 95 beats/min or more (5 points), and pain on lower-limb deep venous palpation and unilateral edema (4 points). In the validation set, the prevalence of pulmonary embolism was 8% in the low-probability category (0 to 3 points), 28% in the intermediate-probability category (4 to 10 points), and 74% in the high-probability category (> or =11 points). Interobserver agreement for the score items was not studied. The proposed score is entirely standardized and is based on clinical variables. It has sustained internal and external validation and should now be tested for clinical usefulness in an outcome study.

Measuring surface mass-balance in the accumulation areas of glaciers is challenging because of the high spatial variability of snow accumulation and the difficulty of conducting annual field glaciological measurements. Here, we propose a method that can solve both these problems for many locations. Ground-penetrating radar measurements and firn cores extracted from a site in the French Alps were first used to reconstruct the topography of a buried end-of-summer snow horizon from a past year. Using these data and surface elevation observations from LiDAR and Global Navigation Satellite System instruments, we calculated the submergence velocities over the period between the buried horizon and more recent surface elevation observations. The differences between the changes in surface elevation and the submergence velocities were then used to calculate the annual surface mass-balances with an accuracy of ±0.34 m w.e. Assuming that the submergence velocities remain stable over several years, the surface mass-balance can be reconstructed for subsequent years from the differences in surface elevation alone. As opposed to the glaciological method that requires substantial fieldwork year after year to provide only point observations, this method, once submergence velocities have been calculated, requires only remote-sensing data to provide spatially distributed annual mass-balances in accumulation areas.

Spatio-temporal variability of the winter surface mass balance is a major uncertainty in the modelling of annual surface mass balance. Moreover, its measurement at high spatio-temporal resolution (sub-200 m) is very useful to force, calibrate or validate models. This study presents the results of year-round field campaigns to study the evolution of the surface mass balance in a ~2 km2 portion of the accumulation zone of the Mer de Glace (France). It is based on repeated LiDAR acquisitions, submergence-velocity measurements and meteorological records. The two methods used to quantify submergence velocities show good agreement. They present a linear temporal evolution without significant seasonal changes but display significant spatial variability. We conclude that a dense network of submergence velocity measurements is required to reduce the uncertainties when computing winter and annual surface mass balance from digital elevation model differencing. Finally, a hight spatio-temporal variability of the winter surface mass balance is highlighted (e.g., a std dev. of 0.92 m in April) even though the topography is homogeneous (std dev. of 25 m). Attempts to relate this variability to different morpho-topographic variables and wind-related indexes show the need for studies conducted at the snowfall event scale to obtain a better understanding of the variability in mass balance at the glacier scale.

Immune and inflammatory mechanisms could play a significant role in pulmonary arterial hypertension (PAH) genesis or progression, especially in patients with connective tissue diseases. Immunosuppressive therapy should be better evaluated in this setting. Monocentric retrospective study. We reviewed the clinical and hemodynamic effects of immunosuppressants administered as first-line monotherapy to 28 consecutive patients with connective tissue disease-associated PAH. All patients received a monthly IV bolus of cyclophosphamide, 600 mg/m2, for at least 3 months, and 22 of 28 patients received systemic glucocorticosteroids. Responders to immunosuppressive therapy were defined as patients who remained in New York Heart Association (NYHA) functional class I or II with sustained hemodynamic improvement after at least 1 year of immunosuppressive therapy without addition of prostanoids, phosphodiesterase type 5 inhibitors, or endothelin receptor antagonists. Eight of 28 patients (systemic lupus erythematosus [SLE], n = 5; mixed connective tissue disease [MCTD], n = 3) [29%] were responders. These patients had a significantly improved 6-min walking distance (available in five patients) and a significant improvement in hemodynamic function. No patients with systemic sclerosis responded, while 5 of 12 patients with SLE and 3 of 8 patients with MCTD did respond. Survival analysis indicated that responders had a better survival than nonresponders. Patients with a lower baseline NYHA functional class and better baseline pulmonary hemodynamics (p < 0.05) were more likely to benefit from immunosuppressive therapy. PAH associated with SLE or MCTD might respond to a treatment combining glucocorticosteroids and cyclophosphamide.

Rock glaciers result from the long-term creeping of ice-rich permafrost along mountain slopes. Under warming conditions, deformation is expected to increase, and potential destabilization of those landforms may lead to hazardous phenomena. Monitoring the kinematics of rock glaciers at fine spatial resolution is required to better understand at which rate, where and how they deform. We present here the results of several years of in situ surveys carried out between 2005 and 2015 on the Laurichard rock glacier, an active rock glacier located in the French Alps. Repeated terrestrial laser-scanning (TLS) together with aerial laser-scanning (ALS) and structure-from-motion-multi-view-stereophotogrammetry (SFM-MVS) were used to accurately quantify surface displacement of the Laurichard rock glacier at interannual and pluri-annual scales. Six very high-resolution digital elevation models (DEMs, pixel size <50 cm) of the rock glacier surface were generated, and their respective quality was assessed. The relative horizontal position accuracy (XY) of the individual DEMs is in general less than 2 cm with a co-registration error on stable areas ranging from 20–50 cm. The vertical accuracy is around 20 cm. The direction and amplitude of surface displacements computed between DEMs are very consistent with independent geodetic field measurements (e.g., DGPS). Using these datasets, local patterns of the Laurichard rock glacier kinematics were quantified, pointing out specific internal (rheological) and external (bed topography) controls. The evolution of the surface velocity shows few changes on the rock glacier’s snout for the first years of the observed period, followed by a major acceleration between 2012 and 2015 affecting the upper part of the tongue and the snout.

Multislice CT (MSCT) combined with D-dimer measurement can safely exclude pulmonary embolism in patients with a low or intermediate clinical probability of this disease. We compared this combination with a strategy in which both a negative venous ultrasonography of the leg and MSCT were needed to exclude pulmonary embolism. We included 1819 consecutive outpatients with clinically suspected pulmonary embolism in a multicentre non-inferiority randomised controlled trial comparing two strategies: clinical probability assessment and either D-dimer measurement and MSCT (DD-CT strategy [n=903]) or D-dimer measurement, venous compression ultrasonography of the leg, and MSCT (DD-US-CT strategy [n=916]). Randomisation was by computer-generated blocks with stratification according to centre. Patients with a high clinical probability according to the revised Geneva score and a negative work-up for pulmonary embolism were further investigated in both groups. The primary outcome was the 3-month thromboembolic risk in patients who were left untreated on the basis of the exclusion of pulmonary embolism by diagnostic strategy. Clinicians assessing outcome were blinded to group assignment. Analysis was per protocol. This study is registered with ClinicalTrials.gov, number NCT00117169. The prevalence of pulmonary embolism was 20·6% in both groups (189 cases in DD-US-CT group and 186 in DD-CT group). We analysed 855 patients in the DD-US-CT group and 838 in the DD-CT group per protocol. The 3-month thromboembolic risk was 0·3% (95% CI 0·1–1·1) in the DD-US-CT group and 0·3% (0·1–1·2) in the DD-CT group (difference 0·0% [−0·9 to 0·8]). In the DD-US-CT group, ultrasonography showed a deep-venous thrombosis in 53 (9% [7–12]) of 574 patients, and thus MSCT was not undertaken. The strategy combining D-dimer and MSCT is as safe as the strategy using D-dimer followed by venous compression ultrasonography of the leg and MSCT for exclusion of pulmonary embolism. An ultrasound could be of use in patients with a contraindication to CT. Swiss National Research Foundation, Projets Hospitaliers de Recherche Clinique (France), Pneumologie Développement (France).

The role of multidetector-row computed tomography (CT) in the diagnosis of pulmonary embolism remains to be determined. In this study, the combined use of multidetector-row CT and D-dimer assays allowed pulmonary embolism to be excluded without the need for lower-extremity ultrasonography. The combined use of multidetector-row CT and D-dimer assays allowed pulmonary embolism to be excluded without the need for lower-extremity ultrasonography. Computed tomography (CT) is increasingly being used as the main thoracic imaging technique in suspected pulmonary embolism. 1 – 4 First-generation single-detector–row helical CT scanners have a 90 percent specificity but only a 70 percent sensitivity for pulmonary embolism. 5 – 8 In series in which venous-compression ultrasonography of the lower limbs and single-detector–row helical CT were performed in all patients with clinically suspected pulmonary embolism, 7 , 9 the proportion of patients with deep venous thrombosis despite findings on CT that were negative for pulmonary embolism was 6 to 9 percent. The implication of this finding is that lower-limb ultrasonography must be combined with CT . . .

D‐dimer is a fragment of crosslinked fibrin resulting from plasmin cleavage of fibrin clots and hence an indirect biomarker of the hemostatic system activation. Early in the coronavirus disease 2019 (COVID‐19) pandemic, several studies described coagulation disorders in affected patients, including high D‐dimer levels. Consequently, D‐dimer has been widely used in not‐yet‐approved indications. Ruling out pulmonary embolism and deep vein thrombosis in patients with low or intermediate clinical suspicion is the main application of D‐dimer. D‐dimer is also used to estimate the risk of venous thromboembolism recurrence and is included in the ISTH algorithm for the diagnosis of disseminated intravascular coagulation. Finally, numerous studies identified high D‐dimer levels as a biomarker of poor prognosis in hospitalized patients with COVID‐19. This report focuses on validated applications of D‐dimer testing in patients with and without COVID‐19.