ICPBR-Working Group Risks posed by dusts: overview of the area and recommendations

Background: In 2008 the poisoning of about 12000 bee colonies was reported from Germany. These poisonings were caused by the drift of dust particles containing the insecticidal substance clothianidin following the seeding of maize seeds, inadequately treated with the insecticide Poncho Pro. Results: Investigations were done on the dust load contained in seed packages of different crops, on the experimental abrasion of dust from treated seeds using the Heubach-Dustmeter as well as on the actual dust drift during the sowing operation of treated seeds with different machinery under field conditions. Resistance to abrasion of treated seeds and subsequent dust drift during sowing operations differ significantly between crops, coating recipes and facilities. Furthermore dust drift depends on particle size, sowing technology as well as on environmental conditions (e.g. wind speed, soil humidity). Conclusions: The drift of dust from treated seeds may pose a risk to honeybees, which needs to be appropriately considered within the authorization process of pesticides. The total quantity of abraded dust as well as the actual emission of dust during the sowing operation can be significantly reduced by technical means (e.g. coating recipe and facility equipment, deflector technology) and by additional mitigation measures (e.g. maximum wind speed). Keywords: honeybee, poisoning, risk, seed treatment, dust, drif

Coaching d'équipe : outils et pratiques /

2e éd

Coaché! /

Comprend des réf. bibliogr. et un index

Synthèse, structure et propriétés physiques de sels de cations radicaux dérives de TétraThiaFulvalène avec des anions organiques (rôle des anions dans la construction du solide cristallin)

Les anions dérivés des diacides (acide oxalique, dérivés de l acide fumarique, ) présentent différentes formes et symétries susceptibles de modifier l arrangement structural dans les sels de cations radicaux dérivés de Tétrathiafulvalène (TTF), et par conséquent de modifier les propriétés physiques (transport, magnétisme, optique.. ;) de ces sels. La préparation et l'étude des propriétés physiques des matériaux obtenus par électrocristallisation sont présentées dans ce travail. Dans un premier temps, le donneur BEDT-TTF a été associé à des anions carboxylate et sulfonate. Une modification, même faible de la nature de la couche anionique peut entraîner des arrangements structuraux très différents. Nous nous sommes ensuite orientés vers l utilisation des donneurs EDTTTF porteurs de groupements amides susceptibles de former des liaisons hydrogène dans l état cristallin et stabiliser l ancrage cation-anion. Dans la dernière partie de ce travail, nous avons utilisé les dérivés TTF halogénés. L exploration de ces sels a permis de mettre en évidence la compétition entre les liaisons hydrogène et halogène. En effet, nous avons observé des interactions fortes de type Oanion Ication qui contribuent à rigidifier fortement l arrangement structural.The anions derived from diacids (acid oxalic, derived from the fumaric acid...) have various forms and symmetries likely to modify structural arrangement in radical cations salts derived from Tétrathiafulvalène (TTF), and consequently to modify the physical properties (transport, magnetism, optics...) of these salts. The preparation and the study of the physical properties of materials obtained by electrocristallization are presented in this work. Initially, the BEDT-TTF donor was associated with carboxylate and sulphonate anions. A modification, even weak, of the nature of the anion layer can involve different structural arrangements. We focused on the use of EDT-TTF donors bearing amides groups that are suitable to form hydrogen bonds in the crystalline state and to stabilize the cation-anion anchoring. The hydrogen bonds OH...O, NH...O and CH...O which were favored in the various crystalline structures allowed the formation of networks of hydrogen bonds supporting a strong molecular cohesion. The analysis of the stuctures of radical cations salts obtained by the association of primary and secondary amide with the same anion highlights the role of each hydrogen atom on the molecular assembly as well as on the collective physical properties of these salts. In the last part of this work, we have halogenated TTF. The exploration of these salts allowed us to highlight the competition between the hydrogen and halogen bonding. Indeed, we observed strong interactions of Oanion...Ication which contribute to strongly rigidify the structural arrangement.ANGERS-BU Lettres et Sciences (490072106) / SudocSudocFranceF

Crystal structure of tetramethyltetrathiafulvalenium (1S)-camphor-10-sulfonate dihydrate

Electro-oxidation of tetramethyltetrathiafulvalene (TMTTF) in the presence of the chiral anion (1S)-camphor-10-sulfonate (S-camphSO3−) in tetrahydrofuran/water medium afforded a 1/1 salt formulated as TMTTF·S-camphSO3·2H2O or 2-(4,5-dimethyl-1,3-dithiol-2-ylidene)-4,5-dimethyl-1,3-dithiole radical ion (1+) [(1S)-7,7-dimethyl-2-oxobicyclo[2.2.1]heptan-1-yl]methanesulfonate dihydrate, C10H12S4+·C10H15O4S−·2H2O. In this salt, two independent TMTTF units are present but, in both cases, the observed bond lengths and especially the central C=C distance [1.392 (6) and 1.378 (6) Å] are in agreement with a complete oxidation of TMTTF which is thus present as TMTTF.+ radical cations. These cations form one-dimensional stacks in which they are associated two by two, forming dimers with short [3.472 (1) to 3.554 (2) Å] S...S contacts. The two S-camphSO3 anions present also form stacks and are connected with each other via the water molecules with many O—H...O hydrogen bonds ranging from 1.86 (3) to 2.15 (4) Å; the O—H...O hydrogen-bonding network can be described as being constituted of C22(6) chains bearing R33(11) lateral rings. On the other hand, the columns of cations and anions are connected through C—H...O hydrogen bonds, forming a system expanding in three directions; finally, the result is a three-dimensional network of O—H...O and C—H...O hydrogen bonds

The role of metamemory on cognitive complaints in cancer patients

International audienceObjective: Although cancer patients frequently report cognitive disturbances, it is commonly asserted a lack of association between cognitive complaints and neuropsychological test performances. Our goal was to better understand the relationships between subjective and objective cognitive scores through a metamemory monitoring assessment.Methods: Sixty cancer patients currently treated by chemotherapy and/or targeted therapy, and 30 healthy controls (HC) were included. Cognitive complaint was assessed by FACT-cog, QAM and DEX questionnaires. One or more z-scores ≤-1.65 among these three questionnaires defined the presence of cognitive complaints. Objective cognitive performances assessed episodic memory, processing speed and executive functions/working memory (ESR paradigm, TMT, Stroop, n-back). Metamemory was assessed with a Judgment of Learning (JOL) task.Results: Patients with cognitive complaints had significantly more depressive and anxiety symptoms (ps < .004), and lower performances on several cognitive tests (ps < .05) than both patients without complaints and HC. More specifically, analyses of the metamemory scores revealed that HC gave significantly more overestimations ("Yes" judgment and incorrect recall) than patients with cognitive complaints (p = .036). For these patients, JOL scores correlated positively with executive functioning (ps < .01).Conclusion: Metamemory monitoring seems to be well-preserved during cancer. What is more, patients make less overestimation than HC, and they do not underestimate their memory. An accurate self-estimation of memory abilities in cancer patients, particularly those with mild cognitive deficits, may play an adaptive function. Our results suggest that the discrepancy frequently reported between cognitive complaints and objective cognitive scores may not be related to metamemory monitoring dysfunction

Phylogeography and population genetics of the maize stalk borer Busseola fusca (Lepidoptera, Noctuidae) in sub-Saharan Africa

The population genetics and phylogeography of African phytophagous insects have received little attention. Some, such as the maize stalk borer Busseola fusca, display significant geographic differences in ecological preferences that may be congruent with patterns of molecular variation. To test this, we collected 307 individuals of this species from maize and cultivated sorghum at 52 localities in West, Central and East Africa during the growing season. For all collected individuals, we sequenced a fragment of the mitochondrial cytochrome b. We tested hypotheses concerning the history and demographic structure of this species. Phylogenetic analyses and nested clade phylogeographic analyses (NCPA) separated the populations into three mitochondrial clades, one from West Africa, and two - Kenya I and Kenya II - from East and Central Africa. The similar nucleotide divergence between clades and nucleotide diversity within clades suggest that they became isolated at about the same time in three different refuges in sub-Saharan Africa and have similar demographic histories. The results of mismatch distribution analyses were consistent with the demographic expansion of these clades. Analysis of molecular variance (AMOVA) indicated a high level of geographic differentiation at different hierarchical levels. NCPA suggested that the observed distribution of haplotypes at several hierarchical levels within the three major clades is best accounted for by restricted gene flow with isolation by distance. The domestication of sorghum and the introduction of maize in Africa had no visible effect on the geographic patterns observed in the B. fusca mitochondrial genome