Cerebellar ataxia, neuropathy, vestibular areflexia syndrome due to RFC1 repeat expansion.

Ataxia, causing imbalance, dizziness and falls, is a leading cause of neurological disability. We have recently identified a biallelic intronic AAGGG repeat expansion in replication factor complex subunit 1 (RFC1) as the cause of cerebellar ataxia, neuropathy, vestibular areflexia syndrome (CANVAS) and a major cause of late onset ataxia. Here we describe the full spectrum of the disease phenotype in our first 100 genetically confirmed carriers of biallelic repeat expansions in RFC1 and identify the sensory neuropathy as a common feature in all cases to date. All patients were Caucasian and half were sporadic. Patients typically reported progressive unsteadiness starting in the sixth decade. A dry spasmodic cough was also frequently associated and often preceded by decades the onset of walking difficulty. Sensory symptoms, oscillopsia, dysautonomia and dysarthria were also variably associated. The disease seems to follow a pattern of spatial progression from the early involvement of sensory neurons, to the later appearance of vestibular and cerebellar dysfunction. Half of the patients needed walking aids after 10 years of disease duration and a quarter were wheelchair dependent after 15 years. Overall, two-thirds of cases had full CANVAS. Sensory neuropathy was the only manifestation in 15 patients. Sixteen patients additionally showed cerebellar involvement, and six showed vestibular involvement. The disease is very likely to be underdiagnosed. Repeat expansion in RFC1 should be considered in all cases of sensory ataxic neuropathy, particularly, but not only, if cerebellar dysfunction, vestibular involvement and cough coexist

Assessment of Uncertainty of Benzene Measurements by Radiello Diffusive Sampler

The uncertainty of benzene measurements obtained by the analysis of thermally desorbable Radiello diffusive samplers was evaluated according to the recent standard EN 14662-4 (2005). Considering the results of laboratory experiments, all the sources of uncertainty regarding the diffusive sampler method characteristics were accessed for the sampling times of 7 and 14 days. The major part of the uncertainty budget (> 79 %) was explained by the variation of the sampling rate due to the environmental factors (temperature and concentration level). For weekly sampling, the diffusive sampler method satisfies the data quality objectives of the European Directive to supply the indicative measurements as well as the reference measurement, since the expanded uncertainty is found lower than 25 %. Using a model-predicted sampling rate which depends on the concentration and temperature, the expanded uncertainty is significantly decreased. The Radiello sampler was found to give correct results for weekly sampling provided that the range of benzene concentrations remained between 0 and 10 µg.m-3, which is generally observed in ambient air monitoring. For 2-week sampling, the expanded uncertainty of measurements exceeds 30 %. However, this diffusive sampler can still be used to carry out an objective evaluation of benzene (minimum quality objective for the accuracy of 100 %). Therefore, the performance of this diffusive sampler method appears to be suitable for the benzene monitoring in ambiant air.JRC.H.4-Transport and air qualit

Spatial and seasonal variability of measured anthropogenic non-methane hydrocarbons in urban atmospheres : Implication on emission ratios

International audienceContinuous measurements of a wide range of non-methane hydrocarbons (NMHC) have been performed since 2001 in Paris megacity and three French medium-sized cities (Grenoble, Marseille, and Strasbourg). After a careful verification of the data measured, the ambient concentrations are used to analyze the spatial and seasonal variability of the anthropogenic NMHC and determine the present NMHC emission ratios relative to acetylene, a useful metric to evaluate and constraint emission inventories. We show that NMHC urban composition is consistent between all cities with no industrial influence and characteristic of the urban emission mixtures, which are mostly dominated by vehicle exhaust emissions. In winter, the urban NMHC composition generally shows an enhancement in combustion-derived products (alkenes, acetylene), C2-C3 alkanes and benzene, which presumes seasonal changes in emission ratio values. Present emission ratios of NMHC relative to acetylene are determined in Paris and Strasbourg both in summer and winter. They generally compare within a factor of two except for C7-C9 aromatics in Paris. On a seasonal basis, summertime emission ratios are three times higher than wintertime ones while they stay constant for combustion derived product (alkenes) and benzene. The unburned gasoline fraction (alkanes and C7-C9 aromatics) shows the maximum difference up to a factor of seven. These findings suggest that the emission ratios reflect seasonal changes in emissions and can be a useful metric to constraint temporally resolved emission inventories at different time of the year

Optimization of a gas chromatographic unit for measuring biogenic volatile organic compounds in ambient air

International audienceA new online gas chromatographic method dedicated to biogenic volatile organic compound (BVOC) analysis was developed for the measurement of a 20 BVOC gaseous mixture (; and 2-carene) at a time resolution of 90 min. The optimized method includes an online Peltier-cooled thermodesorption system sample trap made of Carbopack B coupled to a gas chromatographic system equipped with a 60 m, 0.25 mm internal diameter (i.d.) BPX5 column. Eluent was analysed using flame ionization detection (FID). Potassium iodide was identified as the best ozone scrubber for the 20 BVOC mixture. In order to obtain an accurate quantification of BVOC concentrations, the development of a reliable standard mixture was also required. Quantification of BVOCs was reported with a detection limit ranging from 4 ppt for α-pinene to 19 ppt for sabinene. The main source of uncertainty was the calibration step, stressing the need for certified gaseous standards for a wider panel of BVOCs. This new method was applied for the first time to measure BVOCs in a pine forest during the LANDEX episode 1 field campaign (summer 2017). All target BVOCs were detected at least once during the campaign. The two major monoterpenes observed were β-pinene and α-pinene, representing 60 % of the measured terpenoid concentration on average, while isoprene represented only 17 %. The uncertainties determined were always below 13 % for the six major terpenes

Peroxy radical measurements by ethane – nitric oxide chemical amplification and laser-induced fluorescence during the IRRONIC field campaign in a forest in Indiana

International audienc

Peroxy radical measurements by ethane - nitric oxide chemical amplification and laser-induced fluorescence during the IRRONIC field campaign in a forest in Indiana

Peroxy radicals were measured in a mixed deciduous forest atmosphere in Bloomington, Indiana, USA, during the Indiana Radical, Reactivity and Ozone Production Intercomparison (IRRONIC) during the summer of 2015. Total peroxy radicals ([XO$_2$]≡[HO$_2$]+Σ[RO$_2$]) were measured by a newly developed technique involving chemical amplification using nitric oxide (NO) and ethane (C$_2$H$_6$) followed by NO$_2$ detection by cavity-attenuated phase-shift spectroscopy (hereinafter referred to as ECHAMP – Ethane CHemical AMPlifier). The sum of hydroperoxy radicals (HO$_2$) and a portion of organic peroxy radicals ([HO$_2^∗$]=[HO$_2$]+$Σ_{αi}$[RiO$_2$], 0<α<1) was measured by the Indiana University (IU) laser-induced fluorescence–fluorescence assay by gas expansion instrument (LIF-FAGE). Additional collocated measurements include concentrations of NO, NO$_2$, O$_3$, and a wide range of volatile organic compounds (VOCs) and meteorological parameters. XO$_2$ concentrations measured by ECHAMP peaked between 13:00 and 16:00 local time (LT), with campaign average concentrations of 41±15 ppt (1σ) at 14:00 LT. Daytime concentrations of isoprene averaged 3.6±1.9 ppb (1σ), whereas average concentrations of NO$_x$ ([NO] + [NO$_2$]) and toluene were 1.2 and 0.1 ppb, respectively, indicating a low impact from anthropogenic emissions at this site. We compared ambient measurements from both instruments and conducted a calibration source comparison. For the calibration comparison, the ECHAMP instrument, which is primarily calibrated with an acetone photolysis method, sampled the output of the LIF-FAGE calibration source which is based on the water vapor photolysis method and, for these comparisons, generated a 50 %–50 % mixture of HO$_2$ and either butane or isoprene-derived RO$_2$. A bivariate fit of the data yields the relation [XO$_2$]$_{\textrm{ECHAMP}}$=(0.88±0.02;[HO$_2$ ]+[RO$_2$ ])_{\textrm{IU_cal}}+(6.6±4.5) ppt. This level of agreement is within the combined analytical uncertainties for the two instruments' calibration methods. A linear fit of the daytime (09:00–22:00 LT) 30 min averaged [XO$_2$] ambient data with the 1 min averaged [HO$_2^∗$] data (one point per 30 min) yields the relation [XO$_2$]=(1.08±0.05)[HO$_2^∗$]−(1.4±0.3). Day-to-day variability in the [XO$_2$]/[HO$_2^∗$] ratio was observed. The lowest [XO$_2$ ]/[HO$_2^∗$] ratios between 13:00 and 16:00 LT were 0.8 on 13 and 18 July, whereas the highest ratios of 1.1 to 1.3 were observed on 24 and 25 July – the same 2 d on which the highest concentrations of isoprene and ozone were observed. Although the exact composition of the peroxy radicals during IRRONIC is not known, zero-dimensional photochemical modeling of the IRRONIC dataset using two versions of the Regional Atmospheric Chemistry Mechanism (RACM2 and RACM2 -LIM1) and the Master Chemical Mechanism (MCM 3.2 and MCM 3.3.1) all predict afternoon [XO$_2$]/[HO$_2^∗$] ratios of between 1.2 and 1.5. Differences between the observed ambient [XO$_2$]/[HO$_2^∗$] ratio and that predicted with the 0-D modeling can be attributed to deficiencies in the model, errors in one of the two measurement techniques, or both. Time periods in which the ambient ratio was less than 1 are definitely caused by measurement errors (including calibration differences), as such ratios are not physically meaningful. Although these comparison results are encouraging and demonstrate the viability in using the new ECHAMP technique for field measurements of peroxy radicals, further research investigating the overall accuracy of the measurements and possible interferences from both methods is warranted

Characterization and Near-Field Evolution of Fine Particles Emitted by a Metallurgy Plant: Results of the NANO-INDUS Project

International audienc

Volatile and intermediate volatility organic compounds in suburban Paris: variability, origin and importance for SOA formation

International audienceMeasurements of gaseous and particulate organic carbon were performed during the MEGAPOLI experiments, in July 2009 and January–February 2010, at the SIRTA observatory in suburban Paris. Measurements comprise primary and secondary volatile organic compounds (VOCs), of both anthropogenic and biogenic origins, including C 12 –C 16 n-alkanes of intermediate volatility (IVOCs), suspected to be efficient precursors of secondary organic aerosol (SOA). The time series of gaseous carbon are generally consistent with times series of particulate organic carbon at regional scale, and are clearly affected by meteorology and air mass origin. Concentration levels of anthropogenic VOCs in urban and suburban Paris were surprisingly low (2–963 ppt) compared to other megacities worldwide and to rural continental sites. Urban enhancement ratios of anthropogenic VOC pairs agree well between the urban and suburban Paris sites, showing the regional extent of anthropogenic sources of similar composition. Contrary to other primary anthropogenic VOCs (aromatics and alkanes), IVOCs showed lower concentrations in winter (< 5 ppt) compared to summer (13– 27 ppt), which cannot be explained by the gas-particle partitioning theory. Higher concentrations of most oxygenated VOCs in winter (18–5984 ppt) suggest their dominant primary anthropogenic origin. The respective role of primary anthropogenic gaseous compounds in regional SOA formation was investigated by estimating the SOA mass concentration expected from the anthropogenic VOCs and IVOCs (I / VOCs) measured at SIRTA. From an integrated approach based on emission ratios and SOA yields, 38 % of the SOA measured at SIRTA is explained by the measured concentrations of I / VOCs, with a 2 % contribution by C 12 –C 16 n-alkane IVOCs. From the results of an alternative time-resolved approach, the average IVOC contribution to SOA formation is estimated to be 7 %, which is half of the average contribution of the traditional aromatic compounds (15 %). Both approaches, which are based on in situ observations Published by Copernicus Publications on behalf of the European Geosciences Union. 10440 W. Ait-Helal et al.: Volatile and intermediate volatility organic compounds in suburban Paris of particular I / VOCs, emphasize the importance of the intermediate volatility compounds in the SOA formation, and support previous results from chamber experiments and mod-eling studies. They also support the need to make systematic the IVOCs' speciated measurement during field campaigns

L’économie est une science réflexive

Si l’œuvre de Robert Salais s’inscrit dans le courant de l’économie des conventions qu’il a contribué à fonder, c’est à partir d’une réflexion singulière articulant « détour par l’histoire », intérêt pour le droit et questionnement philosophique. En cela, l’économie telle que la pratique Robert Salais se présente comme une science réflexive procédant d’un renouvellement constant de ses interrogations, à partir des résultats obtenus. Par son souci d’inscrire les analyses menées sur la France dans une perspective internationale, elle est aujourd’hui largement reconnue. Les contributions à cet ouvrage éclairent les quatre grands moments de sa recherche qui s’enchaînent par la « mise en réflexivité » des étapes précédentes : travail, emploi et chômage, mondes de production, question européenne et approche des capacités, quantification et démocratie. Car c’est bien la question politique qui anime la carrière et l’engagement de Robert Salais. Comment redonner aux collectivités humaines l’entendement des fins et la maîtrise de la définition et de l’usage des moyens nécessaires à se gouverner librement ?The work of Robert Salais – one of the founders of the French current known as the “Economie des conventions” – shows a singular reflection that crosses interests for history, law and philosophy. In this respect, economics as practiced by Robert Salais is a reflexive science that constantly renews its interrogations, based on the results obtained