160 research outputs found
Rosa-Maria Gelpi and Francois Julien-Labruyere. A History of Consumer Credit: Doctrines and Practices (Review)
No full textA History of Consumer Credit and Practices, by Rosa-Maria Gelphi and Francois Julien-Labruyere, is reviewed
Multidimensional study of distortions induced by cascaded stimulated Raman scattering in potassium titanyl phosphate
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Common scab and its control in seed-potato crops
No full textIn the Netherlands common scab of the potato is usually caused by Streptomyces scabies (Thaxter) Waksman et Henrici, following Corbaz's description, and rarely by other Streptomyces species. Variation in morphological and other characteristics could not be correlated with lesion types and non-pathogenic S.scabies strains do exist. Three scab types were described, viz. 'normal', 'superficial' and 'russet'. Studies of scab lesion anatomy and reaction to external conditions suggested that superficial and normal scab isolates mainly differ in virulence. The russet scab type does differ in symptom expression and anatomy, in reaction to temperature and moisture and in attacking the root system, but our isolates do belong to S.scabies.After infection the main pathway of the mycelium. seems to be intercellular, and, towards the interior of the lesion the mycelium spreads in cell walls, but is very difficult to find because it stains poorly.Chemical control of scab offers few prospects in the Netherlands. Only PCNB (pentachloronitrobenzene, quintozene) has been applied with some success, but has the disadvantages of yield loss, delay in the expression of virus symptoms and offflavour in tubers for eating. Other chemicals were not sufficiently active to control scab when applied at economic rates.Introduction of antagonists into soil as a measure of scab control proved to be impossible without further far reaching agricultural measures and is economically unattractive. Crop rotations and application of green manures also showed little effect on scab incidence.Irrigation during four weeks after tuber formation starts, proved to be the most effective way of controlling scab. The effect of irrigation on the microbial population of the soil was investigated and irrigation was shown to shift the ratio of pathogenic actinomycetes to bacteria in an unfavourable way for S. scabies.</em
Self-increased acceptance bandwidth of second harmonic generation for high-energy light sources
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Leegstandsaanpak doe je samen: Mogelijkheden voor een gezamenlijke aanpak van kantorenleegstand op gebiedsniveau
No full textVeel van de structurele kantorenleegstand is te vinden op monofunctionele gebieden. Om deze gebieden effectief aan te kunnen pakken is een gebiedsaanpak noodzakelijk. Voor deze aanpak dient samen te worden gewerkt door publieke en private partijen en private partijen onderling. De gemeente dient bij dit alles een faciliterende rol te spelen.Urban Development ManagementReal Estate & HousingArchitecture and The Built Environmen
Déterminants multi-échelles de la dynamique spatio-temporelle des coléoptères carabiques prédateurs de graines d'adventices
No full textPromoting biological pest control in crops requires to understand the functioning of natural enemies in heterogeneous and dynamic agricultural mosaics. This thesis focuses on the study of the determinants that influence the abundance of ground beetles involved in the regulation of weeds via the consumption of their seeds. In an analysis of the variations of species abundance at a national scale we identified the respective role of local and landscape factors and showed that oilseed rape and grassland proportions in the landscape were key determinants of the abundance of carabid species in cultivated fields. We then studied carabid communities through combined measured of their abundance, nutritional status and between-habitat movements, during an entire cropping season, in pairs of habitats consisting in winter oilseed rape fields with either a crop (winter cereal fields) or a semi-natural habitat (grassy field margins) as adjacent habitat. We demonstrated that (i) ground beetles respond to the heterogeneity of arable mosaic (crop type, habitat quality within the same crop type), often with specific responses, (ii) winter oilseed rape plays an important role in the functioning of weed seed-eating carabid species due to its high habitat quality, (iii) variations in habitat quality can influence the movement of beetles to the adjacent habitat and (iv) the presence of a grassy field margin in the vicinity of a crop promotes the maintenance and functioning of several species in arable mosaics.Promouvoir le service de contrôle biologique des bio-agresseurs des cultures nécessite de comprendre le fonctionnement des populations d’ennemis naturels dans des mosaïques agricoles qui sont hétérogènes et dynamiques. Cette thèse porte sur l’étude des déterminants de l’abondance des carabes impliqués dans la régulation des adventices via la consommation de leurs graines. L’analyse des variations d’abondance des espèces à une échelle nationale nous a permis d’évaluer le rôle relatif des facteurs locaux et paysagers et de mettre en évidence le rôle important de la proportion de colza et de prairie dans le paysage sur l’abondance de carabes consommateurs de graines dans les parcelles cultivées. Le suivi expérimental de la composition des communautés de carabes ainsi que du statut nutritionnel et des mouvements de plusieurs espèces dans des dispositifs colza/blé et colza/bordure pérenne sur l’ensemble de la période d’activité des carabes nous a permis de mettre en évidence que (i) les carabes répondent l’hétérogénéité de cette mosaïque agricole (type de culture, qualité de l’habitat au sein d’un même type de culture), avec des réponses souvent spécifiques (ii) que le colza d’hiver joue un rôle important dans le fonctionnement des populations de carabes consommateurs de graines du fait de sa haute qualité d’habitat pour ces espèces, (iii) que la variation de la qualité d’habitat peut jouer sur le mouvement des carabes vers l’habitat adjacent et (iv) que la présence d’une bordure pérenne au voisinage d’une culture favorise le maintien et le fonctionnement de plusieurs espèces consommatrices de graines d’adventices dans la mosaïque agricole
C'était : "Une place à soi"
No full textLe texte Une place à soi a été écrit par Christiane, Martine, Nathalie, Angélique, Agnès, Damien, Harriette, Nadine et Corinne. Joué par Agnès, Alexane, Angélique, Corinne, Damien, Harriette, Martine et Nadine. Direction et mise en scène Damien Labruyere. / photographies Guillaume Clément pour en savoir plus : téléchargez la présentatio
Construction and characterization of a protective antigen-deficient Bacillus anthracis strain
No full textInternational audienceThe pag gene coding for protective antigen (PA), one of the three toxin components of Bacillus anthracis, has been cloned into the mobilizable shuttle vector pAT187 and transferred by conjugation from Escherichia coli to B. anthracis. Using this strategy, an insertionally mutated pag gene constructed and characterized in E. coli, was introduced into B. anthracis Sterne strain. This transconjugant was used to select a recombinant clone (RP8) carrying the inactivated pag gene on the toxin-encoding piasmid, pXO1. Strain RP8 was deficient for PA while still producing the two other toxin components, i.e. lethal factor (LF) and edema factor (EF). In contrast to spores from the wild-type Sterne strain, spores prepared from RP8 were totally non-lethal in mice. These results clearly establish the central role played by PA in B. anthracis pathogenicity
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