589 research outputs found
Étude exploratoire sur l'évaluation de l'impact de l'utilisation des organophosphorés sur la santé de la population limitrophe aux vergers : vergers de la Montérégie
Suite à la demande du groupe Nature-Action de Beloeil/Mont St-Hilaire, la Direction de la santé publique de la Montérégie s'est vu confier par le ministère de la Santé et des Services sociaux, le mandat d'évaluer si l'utilisation de pesticides neurotoxiques en pomiculture représente des risques pour la santé des populations vivant en bordures des vergers. Cette étude a pour objectif de: (1) estimer l'exposition de la population vivant près des vergers (principalement les enfants, y compris les enfants des pomiculteurs); (2) estimer l'exposition de ceux qui procèdent à l'application des pesticides dans les vergers; L'élaboration d'un protocole expérimental au début de l'année 1996 a permis de débuter l'étude exploratoire dès le mois de mai 1996. Des prélèvements urinaires ont été effectués chez les populations à risque et le groupe témoin durant la saison de pulvérisation. Au même moment, des mesures environnementales ont été réalisées (mesure de concentration de pesticides dans l'air et au sol). Une étude de dérive des pesticides en milieu mental a été réalisée partiellement à l'automne de cette même année. Elle vise à documenter la variabilité dans la quantité de dérive en fonction de différents paramètres et de venir en appui aux mesures d'exposition et aux dosages biologiques."--Résumé abrégé par UMI
Water quality and water-use conflicts in Lake Taabo (Ivory Coast)
The Lake Taabo (Ivory Coast, Africa) results of the construction of the Taabo dam on the Ban- dama River. The changes in the water level of the 69-km² lake depend on 1) the rainfall linked to alternating dry/wet seasons; 2) the extraction of water for human uses; 3) the discharge of water from the upstream dam and the volumes tur- bined by the Kossou dam; 4) the various an- thropic effects (discharge of untreated waste water from towns and industries, and leaching from agricultural land). The average concentra- tions of nutrients (NH4-N: 1.1 mg/L, NO3-N: 1.62 mg/L, PO4-P: 10 mg/L, SiO2: 15 mg/L) and chlo- rophyll a (from 4.8 to 16.5 μg/L, average 11.4 μg/L) indicates some degree of eutrophication. The cumulated effects that threaten the ecosys- tem (degradation of water quality and eutrophi- cation) are such that they are likely to interfere with various water uses. In a context of growing health and environmental concerns in Africa, this study demonstrates conflicts between dif- ferent uses of this water resource and the urgent need for an appropriate policy including specific monitoring of lake water quality, wastewater control, and a programme to reduce agricultural fertilizers
Modelling the adsorption of phenolic acids onto ,-alumina particles
International audienceAdsorption of three phenolic acids, namely parahydroxybenzoic acid (4-hydroxybenzoic acid, HPhb), protocatechuic acid (3,4-dihydroxybenzoic acid, HProto) and gallic acid (3,4,5-trihydroxybenzoic acid, HGal) onto ,-AlO particles was studied vs. ligand concentration at pH 5.0, and vs. pH. The oxide surface was characterized with both potentiometric titrations and electrophoretic measurements; a difference in the point of zero salt effect (PZSE) and the isoelectric point (IEP) was evidenced, which could be attributed to the presence of impurities or to the heterogeneity of the oxide. The potentiometric titration experiments lead to the determination of a PZSE of 8.5. Moreover, the particular shape of the curves were fitted in the framework of the constant capacitance model (CCM), using FITEQL 4.0 software, to determine the oxide parameters (protolytic properties and site density). The electrophoretic measurements were fitted in the framework of the double diffuse layer model (DLM) and an IEP of 9.5 was determined. The constant-pH isotherms of the acids were fitted using the CCM. Constant-pH isotherms of HGal and HProto onto the AlO surface sites at pH 5 were similar. Two adsorption sites of different affinities were clearly evidenced for HGal and can also be proposed for HProto. HPhb showed a lower affinity for the surface than the two other acids, as the logK for HPhb is one and a half time lower than the one for HProto when adsorption is described with one adsorption site. As expected for a carboxylic acid, adsorption of HPhb decreased with pH and experimental data were well fitted using three adsorbed species MOHHPhb, MHPhb, and MPhb). Adsorption of HProto and HGal did not change significantly upon increasing pH, meaning that the different functional groups on the aromatic ring (carboxylate and phenolate) were involved in adsorption as pH increases. Dissolution of the oxide was also estimated by measuring the amount of soluble aluminum at pH 5. Increasing acid concentration promoted dissolution, especially for the low concentration range ([acid] < 3 mmol L), but higher acid concentration lowers the increase of the solubility increase, likely due to adsorption on surface of an aluminum-organic complex
Complexation of europium(III) by hydroxybenzoic acids: a time-resolved luminescence spectroscopy study
International audienceComplexation of Eu(III) by two hydroxybenzoic acids, namely p-hydroxybenzoic acid (4 dihydroxybenzoic, HPhbH), and protocatechuic acid (3,4-dihydroxybenzoic, HProtoH2), is studied by time-resolved luminescence spectroscopy (TRLS) in mildly acidic solution. Comparable formation constants are determined at 0.1 mol/L NaCl for EuPhbH[2+] – log10β°(EuPhbH[2+]) = 2.18 ± 0.09 (1sigma) – and 0.01 mol/L NaCl for EuProtoH2[2+] – log10β°(EuProtoH2[2+]) = 2.72 ± 0.07 (1sigma). The stoichiometry and carboxylate complexation of the EuProtoH2[2+] complex is ascertained by varying both pH and ligand concentration. The luminescence decay time of EuPhbH[2+] (τ = 107 ± 5 µs) is comparable with that of Eu(H2O)n[3+] (τ = 110 ± 3 µs), suggesting that luminescence quenching processes compensate the expected increase in decay time due to the dehydration associated with complexation. For EuProtoH2[2+], the luminescence decay time is even shorter (τ = 20 ± 5 µs), evidencing intricate quenching processes
Factors influencing response to Botulinum toxin type A in patients with idiopathic cervical dystonia: results from an international observational study
Objectives Real-life data on response to Botulinum toxin A (BoNT-A) in cervical dystonia (CD) are sparse. An expert group of neurologists was convened with the overall aim of developing a definition of treatment response, which could be applied in a non-interventional study of BoNT-A-treated subjects with CD. Design International, multicentre, prospective, observational study of a single injection cycle of BoNT-A as part of normal clinical practice. Setting 38 centres across Australia, Belgium, Czech Republic, France, Germany, The Netherlands, Portugal, Russia and the UK. Participants 404 adult subjects with idiopathic CD. Most subjects were women, aged 41–60 years and had previously received BoNT-A. Outcome measures Patients were classified as responders if they met all the following four criteria: magnitude of effect (≥25% improvement Toronto Western Spasmodic Torticollis Rating Scale), duration of effect (≥12-week interval between the BoNT-A injection day and subject-reported waning of treatment effect), tolerability (absence of severe related adverse event) and subject's positive Clinical Global Improvement (CGI). Results High rates of response were observed for magnitude of effect (73.6%), tolerability (97.5%) and subject's clinical global improvement (69.8%). The subjective duration of effect criterion was achieved by 49.3% of subjects; 28.6% of subjects achieved the responder definition. Factors most strongly associated with response were age (<40 years; OR 3.9, p<0.05) and absence of baseline head tremor (OR 1.5; not significant). Conclusions Three of four criteria were met by most patients. The proposed multidimensional definition of response appears to be practical for routine practice. Unrealistically high patient expectation and subjectivity may influence the perception of a quick waning of effect, but highlights that this aspect may be a hurdle to response in some patients. Clinical registration number (NCT00833196; ClinicalTrials.gov)
Élaboration et premiers pas de validation de questionnaires pour évaluer la fidélité du modèle de réponse à l’intervention en littératie dans les écoles primaires francophones québécoises
Many French-speaking elementary schools in Quebec implementing the Response to Intervention (RTI) model in literacy need to evaluate the accuracy (or fidelity) of its implementation. In collaboration with schools, this study is aimed at developing and validating instruments to evaluate the fidelity of RTI and its implementation strategies. Self-evaluation questionnaires were developed, including the completion of group meetings with 50 participants to adapt the content to the context and cognitive interviews with 35 participants to pretest the questionnaires. These questionnaires will help inform feedback on the implementation of RTI, and are essential to evaluate the efficacy of RTI.
Keywords: response to intervention, fidelity, implementation, reading, writing, literacy,questionnaires, validityPlusieurs écoles primaires francophones québécoises implantant le modèle de réponse à l’intervention (RAI) en littératie désirent en évaluer la fidélité. En collaboration avec certaines de ces écoles, cette étude vise à élaborer et à valider des instruments d’évaluation de la fidélité de la RAI et de ses stratégies d’implantation. Des questionnaires d’autoévaluation ont été élaborés : 50 participants ont discuté en groupes pour adapter le contenu à leur contexte et 35 participants ont pris part à des entrevues cognitives pour prétester les questionnaires. Ces questionnaires permettront d’alimenter la rétroaction sur l’implantation de la RAI et sont essentiels pour l’évaluation de l’efficacité de la RAI.
Mots-clés : réponse à l’intervention, fidélité, implantation, lecture, écriture, littératie, questionnaires, validit
Évolution des dépenses communales de transports collectifs et de voirie. (Cas des communes de plus de 10 000 habitants)
Cette étude faite au niveau général du budget ne présage cependant rien en ce qui concerne le détail de chacun des postes de dépense. Or, l'hypothèse d'un investissement en grande partie lié aux dépenses passées et aux caractéristiques actuelles est tout à fait plausible pour le chapitre de dépenses de voirie. Elle l'est d'autant plus pour les dépenses de transports collectifs, qui sont une conséquence directe du service offert. Cependant, en ce qui concerne la voirie, les données habituellement utilisées sont celles des balances générales des comptes administratifs des communes. Nous nous intéresserons aux dépenses d'investissement. Pour la voirie ce sont elles qui reflètent la politique communale. Et, en ce qui concerne les transports collectifs, les charges supportées directement par les autorités organisatrices peuvent en effet donner lieu à des parallèles avec les dépenses d'investissement de voirie. L'objet de notre recherche est d'analyser l'évolution conjointe des dépenses de voirie et de transports collectifs sur une période récente (1984-1988) et de déterminer, pour chacune de ces dépenses, la part contrainte pouvant donner lieu à prévision, et en complément la part de " liberté " ou de choix que nous appellerons part de l'innovation.Dépenses d'investissement ; dépenses de voirie urbaine ; dépenses communales ; planification urbaine ; France
MtbHLH1, a bHLH transcription factor involved in Medicago truncatula nodule vascular patterning and nodule to plant metabolic exchanges
This study aimed at defining the role of a basic helix–loop–helix (bHLH) transcription factor gene from Medicago truncatula, MtbHLH1, whose expression is upregulated during the development of root nodules produced upon infection by rhizobia bacteria.We used MtbHLH1 promoter::GUS fusions and quantitative reverse-transcription polymerase chain reaction analyses to finely characterize the MtbHLH1 expression pattern. We altered MtbHLH1 function by expressing a dominantly repressed construct (CRES-T approach) and looked for possible MtbHLH1 target genes by transcriptomics.We found that MtbHLH1 is expressed in nodule primordia cells derived from pericycle divisions, in nodule vascular bundles (VBs) and in uninfected cells of the nitrogen (N) fixation zone. MtbHLH1 is also expressed in root tips, lateral root primordia cells and root VBs, and induced upon auxin treatment. Altering MtbHLH1 function led to an unusual phenotype, with a modified patterning of nodule VB development and a reduced growth of aerial parts of the plant, even though the nodules were able to fix atmospheric N. Several putative MtbHLH1 regulated genes were identified, including an asparagine synthase and a LOB (lateral organ boundary) transcription factor.Our results suggest that the MtbHLH1 gene is involved in the control of nodule vasculature patterning and nutrient exchanges between nodules and roots
Chromatographic, Spectrometric and NMR Characterization of a New Set of Glucuronic Acid Esters Synthesized by Lipase
An enzymatic synthesis was developed on a new set of D-glucuronic acid esters and particularly the tetradecyl-D-glucopyranosiduronate also named tetradecyl D-glucuronate. Chromatographic analyses revealed the presence of the ester as a mixture of anomeric forms for carbon chain lengths superior to 12. TOF/MS and MS/MS studies confirmed the synthesis of glucuronic acid ester. The NMR study also confirmed the structure of glucuronic acid esters and clearly revealed an anomeric (α/β) ratio equivalent to 3/
Coming Full Circle Why Social and Institutional Dimensions Matter for the Circular Economy
In light of the environmental consequences of linear production and consumption processes, the circular economy (CE) is gaining momentum as a concept and practice, promoting closed material cycles by focusing on multiple strategies from material recycling to product reuse, as well as rethinking production and consumption chains toward increased resource efficiency. Yet, by considering mainly cost-effective opportunities within the realm of economic competitiveness, it stops short of grappling with the institutional and social predispositions necessary for societal transitions to a CE. The distinction of noncompetitive and not-for-profit activities remains to be addressed, along with other societal questions relating to labor conditions, wealth distribution, and governance systems. In this article, we recall some underlying biophysical aspects to explain the limits to current CE approaches. We examine the CE from a biophysical and social perspective to show that the concept lacks the social and institutional dimensions to address the current material and energy throughput in the economy. We show that reconsidering labor is essential to tackling the large share of dissipated material and energy flows that cannot be recovered economically. Institutional conditions have an essential role to play in setting the rules that differentiate profitable from nonprofitable activities. In this context, the social and solidarity economy, with its focus on equity with respect to labor and governance, provides an instructive and practical example that defies the constraints related to current institutional conditions and economic efficiency. We show how insights from the principles of the social and solidarity economy can contribute to the development of a CE by further defining who bears the costs of economic activities
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