Comparisons of degradation kinetics of chloroethenes in groundwater between microcosms and field scale

International audienceGroundwater pollution by chlorinated solvents is a major concern since several years. It has been demonstrated that in specific physicochemical conditions, microbial processes like direct reductive dechlorination allow contamination reduction at several sites. Therefore, determination of biodegradation kinetics of chloroethenes is crucial in applying Natural Attenuation protocols on contaminated sites and assessing the potential risks for human health and natural media Biodegradation of chlorinated solvents is effective in highly reduced conditions, which rarely concerns the whole contaminant plume. In this study, direct reductive dechlorination of chloroethenes was studied on two different scales, on microcosms in the laboratory and at the real scale that corresponds to the contaminated site Microcosms studies were conducted in three different ways. (1) sediments sampled from the site and mixed with groundwater modified or not by a synthetic electron donor (Na propionate, Na lactate, toluene), (2) composite sediments coming from several places of the site mixed with groundwater modified or not by a synthetic electron donor; (3) autoclaved sediments and groundwater modified or not by synthetic organic matter. Studies on the real scale were conducted by the achievement of a synthesis of historical data (hydrogeological, geological and physicochemical data) of a polluted site. The synthesis of physicochemical data and then modelling the real site revealed the presence of degradation products of chloroethenes in the plume : cis-1,2-DCE and VC The results of comparisons of degradation kinetics obtained on the laboratory and the field under the same physicochemical conditions showed significant differences. Indeed, biodegradation of chlorinated solvents were faster in lab studies than in the field at the global scale. The existence of chlorinated ethenes biotransformation in microcosms confirmed the presence of a bacterial population able to catalyse reductive dechlorination reaction until CV. It is also likely that the bacterial consortium permitted to degrade other species like electron acceptors; detection of sulphide ions and Fe(II) and the presence of a black precipitate of FeS are proofs of sulphate reducing, ferro reducing and dechlorinating activities. The clear difference that there is between kinetics of degradation on microcosms and field scale could be explained by differences in chemical conditions that are not optimal everywhere in the plume of pollutants. The differences of chemical conditions (electron acceptors, type of natural organic matter, pH, redox potential...) are investigated in details to explain the differences in kinetic constant

Le CROS : mise en place d'un organe de concertation entre les acteurs du développement dans le Sud Ouest malgache

Le Sud Ouest de Madagascar est resté pendant longtemps une région isolée. Les producteurs (analphabètes à 80%) ont particulièrement souffert du manque de formation et de difficultés de communication avec les autres acteurs du développement. Dans ce contexte, avec une offre atomisée, ne comptant pas leurs coûts de production, les agriculteurs sont souvent amenés à vendre à perte pour le plus grand profit des acteurs de l'aval des filières. Depuis 1994, au sein du CROS (Comité Régional d'Orientation du Sud Ouest), les producteurs s'assoient à la même table que les pouvoirs publics (administration et recherche), les opérateurs économiques (agro-industries, établissement financier, exportateurs), les collectivités décentralisées et les bailleurs de fonds organisés en cinq collèges. Le CROS est présidé par un producteur. Des contrats ou des conventions entre membres du CROS ou avec des partenaires extérieurs sont négociés pendant ou à la suite des sessions du CROS qui ont lieu deux fois par an. Cela peut aller des conditions de location vente de matériel agricole à la résolution des problèmes hydrauliques d'un périmètre ou au paiement à la qualité des exportations de pois du Cap. Cette communication voudrait faire le point sur les atouts et les contraintes d'une démarche originale dans laquelle la recherche ne peut être absente

Advancing a National Agenda to Eliminate Disparities in Pain Care: Directions for Health Policy, Education, Practice, and Research

Abstract available at publisher's web site

Participatory analysis for adaptation to climate change in Mediterranean agricultural systems: possible choices in process design (versão Pre Print)

There is an increasing call for local measures to adapt to climate change, based on foresight analyses in collaboration with actors. However, such analyses involve many challenges, particularly because the actors concerned may not consider climate change to be an urgent concern. This paper examines the methodological choices made by three research teams in the design and implementation of participatory foresight analyses to explore agricultural and water management options for adaptation to climate change. Case studies were conducted in coastal areas of France, Morocco, and Portugal where the groundwater is intensively used for irrigation, the aquifers are at risk or are currently overexploited, and a serious agricultural crisis is underway. When designing the participatory processes, the researchers had to address four main issues: whether to avoid or prepare dialogue between actors whose relations may be limited or tense; how to select participants and get them involved; how to facilitate discussion of issues that the actors may not initially consider to be of great concern; and finally, how to design and use scenarios. In each case, most of the invited actors responded and met to discuss and evaluate a series of scenarios. Strategies were discussed at different levels, from farming practices to aquifer management. It was shown that such participatory analyses can be implemented in situations which may initially appear to be unfavourable. This was made possible by the flexibility in the methodological choices, in particular the possibility of framing the climate change issue in a broader agenda for discussion with the actors

Measurement of the Total Active 8B Solar Neutrino Flux at the Sudbury Neutrino Observatory with Enhanced Neutral Current Sensitivity

The Sudbury Neutrino Observatory (SNO) has precisely determined the total active (nu_x) 8B solar neutrino flux without assumptions about the energy dependence of the nu_e survival probability. The measurements were made with dissolved NaCl in the heavy water to enhance the sensitivity and signature for neutral-current interactions. The flux is found to be 5.21 +/- 0.27 (stat) +/- 0.38 (syst) x10^6 cm^{-2}s^{-1}, in agreement with previous measurements and standard solar models. A global analysis of these and other solar and reactor neutrino results yields Delta m^{2} = 7.1^{+1.2}_{-0.6}x10^{-5} ev^2 and theta = 32.5^{+2.4}_{-2.3} degrees. Maximal mixing is rejected at the equivalent of 5.4 standard deviations.Comment: Submitted to Phys. Rev. Let

Electron Antineutrino Search at the Sudbury Neutrino Observatory

Upper limits on the \nuebar flux at the Sudbury Neutrino Observatory have been set based on the \nuebar charged-current reaction on deuterium. The reaction produces a positron and two neutrons in coincidence. This distinctive signature allows a search with very low background for \nuebar's from the Sun and other potential sources. Both differential and integral limits on the \nuebar flux have been placed in the energy range from 4 -- 14.8 MeV. For an energy-independent \nu_e --> \nuebar conversion mechanism, the integral limit on the flux of solar \nuebar's in the energy range from 4 -- 14.8 MeV is found to be \Phi_\nuebar <= 3.4 x 10^4 cm^{-2} s^{-1} (90% C.L.), which corresponds to 0.81% of the standard solar model 8B \nu_e flux of 5.05 x 10^6 cm^{-2} s^{-1}, and is consistent with the more sensitive limit from KamLAND in the 8.3 -- 14.8 MeV range of 3.7 x 10^2 cm^{-2} s^{-1} (90% C.L.). In the energy range from 4 -- 8 MeV, a search for \nuebar's is conducted using coincidences in which only the two neutrons are detected. Assuming a \nuebar spectrum for the neutron induced fission of naturally occurring elements, a flux limit of Phi_\nuebar <= 2.0 x 10^6 cm^{-2} s^{-1}(90% C.L.) is obtained.Comment: submitted to Phys. Rev.

Comparison of Endoscopic Ultrasound-Directed Transgastric Endoscopic Retrograde Cholangiopancreatography Outcomes Using Various Technical Approaches

Background and study aims  Roux-en-Y gastric bypass presents an anatomic challenge for patients needing ERCP. EUS-directed transgastric ERCP (EDGE) offers high clinical success but carries considerable risk of adverse events (AEs) with no standardized technical approach. In our study, we review the safety and efficacy of our various EDGE technical approaches. Patients and methods  A retrospective single-center study of all patients who underwent EDGE procedures between February 2018 and November 2019. Primary outcomes included comparing the technical and clinical success, AEs, and lumen-apposing metal stent (LAMS) migration rates per access route (gastrogastric vs jejuno-gastric), number of procedure stages (single-stage vs two-stage), and stent size (15 mm vs 20 mm). Secondary outcomes included LAMS migration characteristics and management. Results  Thirty-two EDGE procedures were performed in 29 patients, including 17 single-stage and 15 two-stage procedures, 23 gastrogastric, and nine jejuno-gastric routes, fourteen 15-mm and 17 20-mm LAMS. Overall technical and clinical success rates were 96.9 % and 87.1 %, respectively, without any significant difference between groups. The overall AE rate was (34.4 %) and was significantly lower in the 20-mm LAMS group compared to the 15-mm group (17.6 % vs 57.1 %, P  = 0.03). Compared to two-stage procedures, there was no significant difference in AEs with single-stage procedures (35.3 % vs 33.3 %, P  = 0.33). The LAMS migration rate was (25 %) with no significant difference between groups. Most migrations were around the index procedure and managed endoscopically (62.5 %). Conclusions  EDGE offers high clinical success rates but AE rates remain significant. In our series, a 20-mm LAMS resulted in a significantly lower AE rate than the 15-mm LAMS. Large multicenter studies are recommended to identify technical factors leading to an optimal EDGE procedure

Informed consent in veterinary medicine: ethical implications for the profession and the animal 'patient'

Informed consent processes are a vital component of both human and veterinary medicine. Current practice encourages veterinarians to learn from insights in the human medical field about how best to achieve valid consent. However, drawing on published literature in veterinary and medical ethics, this paper identifies considerable differences between the purposes of veterinary and human medical consent. Crucially, it is argued that the legal status of animal patients as ‘property’ has implications for the ethical role of veterinary informed consent and the protection of the animal ‘patient’. It is suggested that veterinary informed consent should be viewed as an ethical pivot point where the multiple responsibilities of a veterinary professional converge. In practice, balancing these responsibilities creates considerable ethical challenges. As an example, the paper discusses the renewed call for UK veterinarians to make animal welfare their first priority; we predict that this imperative may increasingly cause veterinary informed consent to become an ethical pressure point due to tensions caused by the often conflicting interests of animals, owners and the veterinary profession. In conclusion, the paper argues that whilst gaining informed consent can often be presented as a robust ethical justification in human medicine, the same cannot be said in veterinary medicine. If the veterinary profession wish to prioritise animal welfare, there is an urgent need to re-evaluate the nature of authority gained through owner informed consent and to consider whether animal patients might need to be better protected outside the consent process in certain circumstances

Drastic shifts in the Belgian bumblebee community over the last century

peer reviewedCliPS - Fédération Wallonie Bruxelle

Improved functionalization of oleic acid-coated iron oxide nanoparticles for biomedical applications

Superparamagnetic iron oxide nanoparticles can providemultiple benefits for biomedical applications in aqueous environments such asmagnetic separation or magnetic resonance imaging. To increase the colloidal stability and allow subsequent reactions, the introduction of hydrophilic functional groups onto the particles’ surface is essential. During this process, the original coating is exchanged by preferably covalently bonded ligands such as trialkoxysilanes. The duration of the silane exchange reaction, which commonly takes more than 24 h, is an important drawback for this approach. In this paper, we present a novel method, which introduces ultrasonication as an energy source to dramatically accelerate this process, resulting in high-quality waterdispersible nanoparticles around 10 nmin size. To prove the generic character, different functional groups were introduced on the surface including polyethylene glycol chains, carboxylic acid, amine, and thiol groups. Their colloidal stability in various aqueous buffer solutions as well as human plasma and serum was investigated to allow implementation in biomedical and sensing applications.status: publishe