5,066 research outputs found

    Protection of the 13 T Nb3Sn Fresca II dipole

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    The EuCARD project aims on construction of a 19 T hybrid dipole; it will be made of a 6 T HTS dipole associated to a 13 T outsert Nb3Sn dipole [1]. This paper reviews the quench analysis and protection of the 13 T Nb3Sn dipole.Comment: 5 pages, Contribution to WAMSDO 2013: Workshop on Accelerator Magnet, Superconductor, Design and Optimization; 15 - 16 Jan 2013, CERN, Geneva, Switzerlan

    Mesure de l'intensité et de la sélectivité du bronzage zooplanctonique diurne et nocturne sur le peuplement physoplanctonique de la retenue Al Massira (Maroc)

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    La retenue de barrage Al Massira (Maroc) constitue une pièce maîtresse dans le plan d'aménagement du bassin versant de l'Oum Er Rbia. Elle se situe dans la province de Settat, à 120 km au sud-est de Casablanca. La mesure de l'intensité du broutage zooplanctonique sur le peuplement phytoplanctonique a été réalisée à trois périodes différentes; le 20 mars 1992 d'une part et les 27 et 28 mai 1992 d'autre part, avec respectivement des mesures de jour et de nuit . Pour cela, une analyse de l'évolution des densités phytoplanctoniques au sein d'enceintes immergées in situ à 5 et 15 m pendant 8 heures, en absence (enceintes témoins) et en présence (enceintes expérimentales) de zooplancton, a été réalisée. Les résultats obtenus montrent que:- La technique adoptée est performante dans la mesure où les différences entre les densités algales entre les temps initial et final sont en général significatives dans les deux enceintes. - Conformément aux données de la littérature, le broutage apparaît bien comme sélectif; de nombreuses espèces n'apparaissant pas être consommées. - La sélection effectuée par le zooplancton est principalement basée sur la taille des cellules. Toutefois, à tailles égales, certaines espèces phytoplanctoniques semblent être consommées préférentiellement par les copépodes. - Seules les espèces algales présentant un développement important dans les enceintes témoins sont soumises à la prédation.The Al Massira reservoir, located in the district of Settat 120 km south-east of Casablanca, is of great importance notably at the level of the management of the Oum Er Rbia River-catchment basin.Several grazing experiments were performed to assess the intensity of phytoplankton predation by zooplankton species, on 20 March l992, 27 and 28 May 1992, respectively, over the day and the night. Two enclosures were used and incubated in situ at 5 and 15 m over 8 hours, The first enclosure consisted of a mixture of several phytoplankton and zooplankton species. The second was free of zooplancton.The results clearly demonstrated that the technique used in this work seemed to be effective in that a signifïcant difference between the initial and final numbers of phytoplankton species incubated in the enclosure was detected. In addition, we confirmed several literature reports relative to the selective characteristics of herbivore predation on algae: large phytoplankton (e.g., Peridinium cinctum, Ceratium hirundinellaand Staurastrum pingue) were not affected. The grazing pressure depended on the size of preys and on the exudates released by the physiofogically active small phytoplankton species (e.g., Oocystis crassa, Cyclotella sp.) evolving in the enclosures. Among small preys, only species with high growth rate (estimed in the control flask, e.g., Cosmarium sp. and Tetraedron sp.) were subjected to the zooplankton predation. The copepod nightgrazing was lower than that recorder during the day, probably due to a decrease in their ability to detect preys in the dark.Our result contradict several results obtained by the method of NANEY (1971) according to which grazing increases during the night.Two assumptions may be proposed to explain such a discrepancy:- The zooplankton community of the Al Massira Reservoir was quantitatively dominated by the Calanoid Neolovenula alluaudi.Yet, according to HANEY and HALL (1975), these Copepods showed a slight diel grazing change compared to that of Cladocera. It seemed likely that these temporal variabilities were not statistically significant but rather inherent to the overall internal fluctuation oftlte cell metabolism.- The HANEY (1971) method allows estimation of the water volume per unit time, which transits along the digestive tract of zooplankters. Nevertheless, this technique was mostly performed in markedly stratified natural lakes. From a strictly physiological point of view, and as demonstrated by MC LAREN (1963), organisms which evolved in deep layers (low temperature) became metabolically more active when they reached superficial layers (increased temperature). Clearly, this increase in the cell metabolism abilities is translated into a higher volume of water passing through the digestive tract but not necessarily into an increase in ingested phytoplankton preys. Our results went along with the aforementioned interpretation since we clearly demonstrated an optimal Copepoda-grazing selectivity. However, the selection of preys would not imply a direct relationship between the ingested volume of water and energetic inputs

    人格(パースナリティー)理論に就いて

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    The aim of this study was to evaluate the ability of new rubbery liners, used as a cervical increment, to relieve contraction stress and thereby reduce the formation of cervical gaps in class II composite restorations. The investigated liners were made of polyester-acrylate (PE(1), PE(2) or PE(3)) or silicone-acrylate (S), mixed with UDMA, without (A, B, C, D) or with HEMA (AH, BH, CH, DH). A silanized filler was added to the mixture, DH, to give composites with 20, 40, 60, and 70% (w/w) of filler (DHF20, DHF40, DHF60, DHF70, respectively). The presence and width of cervical gaps were determined using a light microscope. Statistical analysis showed that six of the 12 rubbery liners (AH-DH, DHF20-DHF40) significantly decreased gap formation in comparison with the control group. In addition, the polymerization shrinkage, flow, and strain capacity of these liners were measured and the influence of these factors on gap formation was examined. Two- and three-dimensional regression analyses showed significantly negative linear correlations between gap formation and strain capacity, and between gap formation and flow, and a significantly positive linear correlation between gap formation and shrinkage

    Inheritance of resistance to Kabatielle eyespot of maize

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    Des études génétiques portant sur la résistance du maïs-grain (Zea mays) aux attaques de la kabatiellose causée par le Kabatiella zeae ont consisté en des essais de croisements diallèles 8x8. Chez les huit lignées utilisées, l'action additive des gènes semble avoir été déterminante quant à la résistance aux attaques du feuillage. Il y a eu un certain degré de dominance chez quatre groupes de gènes. L'hérédité au sens strict a été évaluée à 75%. La lignée V312 a été la plus résistante à la maladie tandis que les lignées F522, WF9 et L2039 sont apparues sensibles.Genetic studies of resistance to Kabatiella zeae causing eyespot in grain maize (Zea mays) were conducted using an 8 x 8 complete diallel cross. In the eight inbreds used, the additive component appeared to be the most important in determining resistance to eyespot. There appeared to be at least four genes showing some degree of dominance. Narrow-sense heritability was estimated at 75%. Inbred V312 was the most resistant line among the eight lines in this diallel set, whereas F522, WF9 and L2039 appeared to be susceptible

    Exploring the relationship between education and obesity

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    An epidemic of obesity has been developing in virtually all OECD countries over the last 30 years. Existing evidence provides a strong suggestion that such an epidemic has affected certain social groups more than others. In particular, a better education appears to be associated with a lower likelihood of obesity, especially among women. This paper sheds light on the nature and the strength of the correlation between education and obesity. Analyses of health survey data from Australia, Canada, England, and Korea were undertaken with the aim of exploring this relationship. Social gradients in obesity were assessed across the entire education spectrum, overall and in different population sub-groups. Furthermore, investigations testing for mediation effects and for the causal nature of the links observed were undertaken to better understand the underlying mechanisms of the relationship between education and obesity. © OECD 2011

    Étude préliminaire sur les échanges de phosphore à l'interface eau- sédiment au sein de la retenue d'Al Massira (Maroc)

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    Les échanges de phosphore à l'interface eau-sédiment ont été étudiés dans la retenue Al Massira. La campagne de prélèvements a été menée pendant la faible oxygénation des eaux profondes au mois d'octobre 1991. Les mesures des échanges de phosphore ont été réalisées in situ en chambre benthique.Les valeurs de pH sont élevées et reflètent clairement l'influence de la nature géologique du bassin versant sur la composition chimique des eaux. Ce bassin versant, formé essentiellement de roches sédimentaires calcaires, est vraisemblablement à l'origine des concentrations élevées en calcium mesurées dans les chambres benthiques.En période de faible oxygénation, on note une augmentation des teneurs en phosphore particulaire dans les eaux surnageantes en raison de la présence de complexes calcium-phosphore, fer-phosphore et manganèse-phosphore. En période d'anoxie, la réduction de ces complexes est accompagnée d'une aug- mentation des teneurs en phosphore.La densité bactérienne et la concentration en phosphore total et notamment en orthophosphates suivent une évolution temporelle comparable. Une fraction non négligeable du phosphore particulaire serait liée aux bactéries.Des mesures drastiques de déphosphatation du tributaire Oum Errbia doivent être prises pour éviter la dissociation des complexes Ca, Fe, Mn-Phosphore et le relargage de phosphore biodisponible.Phosphorus exchange at the sediment-water interface was studied in the Al Massira reservoir. This reservoir, located on the Oum Errbia river, is the most important freshwater resource in Morocco. It provides drinking water to the whole population of Casablanca and contributes to farming and to the functioning of several industrial plants. Our investigations were made in October 1991 and coincided with low oxygen concentrations in the deep layers. The measurements of phosphorus exchange have been made in sitn with a benthic chamber device.The results showed that these exchanges were regulated by a combination ofthe physical chemical variability of the environment and the geological composition of the catchment basin.The pH, which permanently exceeded 7 in Massira, suggests that calcium-bound phosphorus was primarily CaHFO4. Moreover, given the high phosphonrs inputs into the reservoir (570 tonnes. year-1), and despite the fact that, as soon as it reached the reservoir, a large fraction of this element was associated with to calcium, it's likely that the Massira reservoir is subject to eutrophication.In low oxygenated deep layers, we observed an increase in particulate phosphorus concentrations of the overlying water, due to the simultaneous presence of calcium-phosphorus, iron-phosphorus and manganese-phosphorus forms. Under anoxic conditions, the reduction ofthese complexes resulted in an increase of phosphorus concentrations.Bacterial cell numbers and total phosphorus concentratioru showed a comparable temporal behaviour. This would suggest that attached bacteria contributed at least partially to the total particulate phosphoms concentrations.We suggest that a drastic control of phosphorus inputs into the waters must be done through a program of dephosphorylation of tributaries to avoid the dissocation of calcium-, iron-, manganese-bound phosphorus with release upwards of bioavailable phosphorus
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