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Notes: The interaction of ioxynil and mecoprop applied to Stellaria media (L.) Vill. was investigated under controlled environmental conditions and several statistical methods were used to test for positive or negative interactions employing a multiplicative survival model. Information on the contribution of each herbicide to the total effect was gained by recording numbers of shoots and leaves, internode length and photosynthetic carbon dioxide exchange. Results showed that ioxynil and mecoprop can interact strongly, but the degree and direction of this interaction varied according to both the growth stage of the plants at spraying and the length of time between spraying and assessment of response. In general a synergistic interaction occurred where plants were younger at spraying and with a longer period of time between spraying and assessment of effects. These results are discussed in relation to the potential for using reduced doses of this herbicide mixture, and the importance of the design and interpretation of interaction studies are considered. Action réciproque de l'ioxynil et du MCPP appliqués sur Stellaria media (L.) Vill.L'action réciproque de l'ioxynil et du MCPP, appliqués sur Stellaria media (L.) Vill., a fait l'objet d'une étude dans des conditions ambientales contrôlées; plusieurs méthodes d'analyse statistique ont été mis en oeuvre pour déceler des actions réciproques positives ou négatives en utilisant un modèle multiplicatif de survivance. Les nombres de pousses et de feuilles, la longeur de l'entre-noeud et l'échange photosynthétique de l'acide carbonique ont été signalés pour obtenir des renseignements sur la part de chaque herbicide dans l'effet global. Les résultats ont révélé que l'ioxynil et le MCPP sont capables d'une forte action réciproque mais le niveau et le sens de cette interaction ont varié selon le stade de développement des plantes au moment de la pulvérisation ainsi que l'intervalle entre la pulvérisation et l'évaluation de la réaction. En général, une interaction synergique s'est fait voir plus les plantes étaient jeunes au moment de la pulvérisation et plus l'intervalle entre celle-ci et l'evaluation des effets était grand. Ces résultats sont discutées par rapport à la possibilité d'employer des doses réduites de cette association herbicide; on considère aussi l'importance du plan expérimental et de l'interprétation dans les études d'actions réciproques. Wechselwirkung von Ioxynil und Mecoprop auf Stellaria media (L.) Vill.Am Beispiel von Stellaria media (L.) Vill. wurde das Zusammenwirken von Ioxynil und Mecoprop unter kontrollierten Umweltbedingungen studiert. An einem multiplikativen Ueberlebensmodell wurden verschiedene statistische Methoden eingesetzt, um positive oder negative Wechselwirkungen aufzudecken. Zur Erarbeitung der notwendigen Information über den Beitrag jedes Herbizids zur Gesamtwirkung wurden folgende Parameter bestimmt: Anzahl Sprosse und Blätter, Länge der Internodien und der photosynthetische CO2-Austausch. Die Resultate zeigten, dass Ioxynil und Mecoprop stark zusammenwirken können, wobei aber Grad und Qualität der Wechselwirkung (positiv oder negativ) je nach Alter der Pflanzen bei der Behandlung und Intervall zwischen Behandlung und Messung der Reaktion variierten. Der Trend zu Synergismus war umso ausgeprägter, je jünger die Pflanzen bei der Behandlung und je länger die Intervalle zwischen letzterer und den Messungen waren. Die Ergebnisse werden einerseits im Hinblick auf die Möglichkeit der Verwendung reduzierter Aufwandmengen dieser Herbizidmischung diskutiert, aber auch bezüglich der Wichtigkeit der Versuchsanlage zur Interpretation von Untersuchungen über Wechselwirkungen.

Notes: Bindii dermatitis is seen in children in late spring and early summer. The rash involves the knees and often affects the soles, elbows, forearms and palms. It resolves in winter. Recognition is important as the rash has been confused with other conditions.

Notes: Fifty-four patients with facial acne vulgaris received local treatment with 0.05% retinoic acid lotion over a trial period of 12 weeks. Significant improvement occurred in 80% of patients. Side effects of treatment in the nature of an unacceptable degree of erythema and peeling, or exacerbation of acne, proved to be a problem in only a small percentage.

Notes: Abstract The reaction of ethylene catalyzed by metallic molybdenum at 875 K yields higher hydrocarbons (〉C2) with a distribution that is well described by a Schulz-Flory plot suggesting that their formation arises from the polymerization of surface C1 species. This observation is in accord with results from surface science experiments that show facile C=C cleavage in alkenes. A similar molybdenum-catalyzed reaction of propylene yields metathesis and hydrogenolysis products. In view of the product distribution found with ethylene, these products are proposed to arise from the recombination of surface species formed by propylene dissociation. This result is confirmed by modifying the Schulz-Flory function assuming equal surface coverages of carbenes and methyl carbenes which adequately predicts the measured product distribution.

Notes: Abstract The activity of various molybdenum oxides supported on a molybdenum foil substrate for the catalysis of propylene metathesis is measured using an isolatable, high-pressure reactor incorporated in an ultra-high vacuum (UHV) chamber which allows samples to be transferred directly from vacuum into the catalytic test chamber. MoO x samples are prepared both by oxidation of metallic molybdenum and reduction of molybdenum trioxide. The results suggest that the presence of an oxygen overlayer on the catalyst inhibits reaction and that the ranking of activity for metathesis at 870 K using 450 Torr of propylene for oxide samples is MoO2〉MoO3〉Mo where MoO2 is ∼ 30 times more active than molybdenum metal under these conditions.

Notes: [Auszug] MUCH attention has been directed to estimating the relative extent to which recently deposited strontium-90 as opposed to the cumulative total in the soil is responsible for the contamination of milk and other components of diet. In addition to elucidating mechanisms of food chain transfer, this ...

Notes: [Auszug] Large (5 mgm.) crystals of tarium azide mono-hydrate, grown under carefully controlled conditions, were dried and dehydrated slowly in vaeuo at room temperature. The decompositions were carried out in vacuo on a heated microscope stage using a magnification of 500 x. As noted earlier, the rate of ...

Notes: [Auszug] Fig. 1 Strontium-90 in fallout and milk in the United Kingdom, 1958-1970. a, Mean results of surveys of deposition and contamination of milk conducted respectively by the Atomic Energy Research Establishment, Harwell7, and Letcombe Laboratory. ???, Milk; . . . ., cumulative deposit; - - - , annual ...

Notes: [Auszug] AS the radiation dose which man receives from strontium-90 depends on its concentration in bone, the effects of environmental contamination with this nuclide can be assessed most directly by the analysis of bone. The difficulties of obtaining adequately representative samples of bone, particularly ...