1,617 research outputs found

    Evidence that the Pomeron transforms as a non-conserved vector current

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    The detailed dependences of central meson production on the azimuthal angle phi, t and the meson J^P are shown to be consistent with the hypothesis that the soft Pomeron transforms as a non-conserved vector current. Further tests are proposed. This opens the way for a quantitative description of q-qbar and glueball production in p p -> p M p.Comment: 12 pages, latex, 4 figure

    Effect of seed mass and number of cotyledons on seed germination after heat treatment in Pinus sylvestris L. var. iberica Svob.

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    Aim of study: We investigated the combined effect of seed mass and number of cotyledons on the seed germination of Pinus sylvestris var. iberica (Iberian Scots pine) in simulated fire conditions.Material and Methods: We used 3,600 fresh seeds extracted from 158 cones obtained from 10 pine trees located at the Biological Station of the Complutense University (Guadarrama mountains, Madrid region). All the seeds were individually weighed and assigned to one of the two following seed mass classes: class I (1.6-12.5 mg) and class II (12.6-145.0 mg). Germination capacity (GC) and mean germination time (MGT) were studied in combined experiments of four different temperatures (100°, 125°, 150° and 175°C) and two exposure times (1 and 5 minutes) together with a control (no treatment). Four replicates of 50 seeds each were used for each treatment and hydrated daily for 14 days to germinate under constant illumination. The number of cotyledons was counted in seedlings.Main results: Germination was depressed at above 125°C for 5 min. GC and MGT were negatively related, and were influenced by temperature and exposure time. Seed mass was found to have a significant effect on GC at some moderate heat treatment but not on MGT. The number of cotyledons was positively correlated to seed mass but there was not found correlated with germination after seed heat treatments.Research highlights: In the case of the Iberian Scots pine, higher seed mass mitigate the negative effects of temperature on seed germination after moderate heat treatment simulating fire.Keywords: Fire disturbance; germination; Mediterranean mountains; Pinus sylvestris L. var. Iberica; temperature.

    New effects observed in central production by experiment WA102 at the CERN Omega Spectrometer

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    A partial wave analysis of the centrally produced KK and pipi systems shows that the fJ(1710) has J = 0. In addition, a study of central meson production as a function of the difference in transverse momentum (dPT) of the exchanged particles shows that undisputed qqbar mesons are suppressed at small dPT whereas the glueball candidates are enhanced and that the production cross section for different resonances depends strongly on the azimuthal angle between the two outgoing protons.Comment: 5 pages, Latex, 3 Figures to appear in the proceeding of PANIC 99, Uppsala, Sweden, June 199

    Angiotensin type-2 (AT-2)-receptor activation reduces renal fibrosis in cyclosporine nephropathy: evidence for blood-pressure independent effect

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    Compound 21 (C21), selective agonist of AT2 receptors, shows antinflammatory effects in hypertension and nephroprotection in diabetes. The aim of this study was to evaluate the effects of C21 in cyclosporine nephropathy, which is characterized mainly by tubulo-interstitial fibrosis. Ten days before and during the experimental periods, low-salt diet was administered to Sprague Dawley rats. Cyclosporine-A (15mg/kg/day, i.p.) and cyclosporine-A plus C21 (0.3 mg/kg /day, i.p) were administered for 1 and 4 weeks. Control groups was left without any treatment. Blood pressure (plethysmographic method) and 24 hour albuminuria were measured once a week. At the end of the experiments, the kidneys were excised for histomorphometric analysis of renal fibrosis and for immunohistochemical evaluation of inflammatory infiltrates and type I and IV collagen expression.After 1 and 4 weeks, the rats treated with cyclosporine showed a significant increase (p <0.01) in blood pressure, no significant changes in albuminuria, a significant increase (p <0.01) in glomerular and tubulo-interstitial fibrosis and inflammatory infiltrates as compared to the control rats. Treatment with C21 did not modify the cyclosporine dependent increase of blood pressure, which was higher than in control rats, but after 4 weeks of treatment significantly reduced (p <0.01) glomerular and tubulo-interstitial fibrosis, type 1 collagen expression and macrophage infiltration, as compared to rats treated with cyclosporine.The administration of C21 showed a protective effect on cyclosporine nephropathy, decreasing renal fibrosis and macrophage infiltration. These data suggest that C21 may counteract tubulo-interstitial fibrosis, the most potent predictor of the progression of renal diseases

    The GRAAL high resolution BGO calorimeter and its energy calibration and monitoring system

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    We describe the electromagnetic calorimeter built for the GRAAL apparatus at the ESRF. Its monitoring system is presented in detail. Results from tests and the performance obtained during the first GRAAL experiments are given. The energy calibration accuracy and stability reached is a small fraction of the intrinsic detector resolution.Comment: 19 pages, 14 figures, submitted to Nuclear Instruments and Method

    Demonstration of dynamic restoration in segment routing multi-layer SDN networks

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    Dynamic traffic recovery is designed and validated in a multi-layer network exploiting an SDN-based implementation of Segment Routing. Traffic recovery is locally performed from the node detecting the failure up to the destination node without involving the SDN controller. Experimental results demonstrate recovery time within 50 ms

    Efeito do dano mecânico na qualidade fisiológica e na capacidade de expansão de sementes de milho pipoca.

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    Com o objetivo de dar subsidio aos produtores de sementes e/ou graos de milho pipoca, para melhorar a qualidade fisiologica da producao, sementes da cultivar CMS-43 foram submetidas a tres niveis de danificacao mecanica (sem danos, com danos e com danos dobrados), e avaliadas pelos testes de germinacao, vigor (condutividade eletrica) e capacidade de expansao. Os resultados demonstraram que sementes danificadas reduzem significativamente a germinacao, o vigor e a capacidade de expansao das sementes. Concluiu-se que indiferente a finalidade da producao, sementes e/ou graos, a colheita do milho pipoca precisa ser feita com o minimo de danificacao mecanica possivel, para propiciar um produto com maxima qualidade
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