170,517 research outputs found

    Convite de jogo de futebol

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    Convite impresso para o jogo entre os times “Gomes Barbosa”, de Viçosa, e Arnaldo Carneiro F. C. de Ponte Nova, em homenagem a Miss Clarissa Rolfs e Peter Henry Rolfs

    Fusion rate enhancement due to energy spread of colliding nuclei

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    Experimental results for sub-barrier nuclear fusion reactions show cross section enhancements with respect to bare nuclei which are generally larger than those expected according to electron screening calculations. We point out that energy spread of target or projectile nuclei is a mechanism that generally provides fusion enhancement. We present a general formula for calculating the enhancement factor and provide quantitative estimate for effects due to thermal motion, vibrations inside atomic, molecular, or crystal system, and due to finite beam energy width. All these effects are marginal at the energies that are presently measurable; however, they have to be considered in future experiments at still lower energies. This study allows us to exclude several effects as a possible explanation of the observed anomalous fusion enhancements, which remain a mystery

    Prospects for underground accelerator research

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    A summer institute was convened at the Gran Sasso Laboratory (Italy), 27. June to 7. July 1994, in part to explore the advantages of an accelerator laboratory deep underground, particularly for crucial nuclear-astrophysics measurements presently limited at low energies by cosmic-ray backgrounds. Here we review specific reactions identified as needing further study in a low-background environment, and outline suitable facilities to carry out such studies. © 1995 Springer-Verlag

    Fusion rate enhancement due to energy spread of colliding nuclei

    No full text
    Experimental results for sub-barrier nuclear fusion reactions show cross section enhancements with respect to bare nuclei which are generally larger than those expected according to electron screening calculations. We point out that energy spread of target or projectile nuclei is a mechanism that generally provides fusion enhancement. We present a general formula for calculating the enhancement factor and provide quantitative estimate for effects due to thermal motion, vibrations inside atomic, molecular, or crystal system, and due to finite beam energy width. All these effects are marginal at the energies that are presently measurable; however, they have to be considered in future experiments at still lower energies. This study allows us to exclude several effects as a possible explanation of the observed anomalous fusion enhancements, which remain a mystery

    Sozialleistungen für Nicht-Deutsche. Zugang durch globale Gleichheitsrechte

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    Davy U. Sozialleistungen für Nicht-Deutsche. Zugang durch globale Gleichheitsrechte. In: Rolfs C, ed. Migration und Sozialstaat. Sozialrechtslehrertagung 2018 : 28. Februar 2018 bis 1. März 2018 in Speyer . Schriftenreihe des Deutschen Sozialrechtsverbandes (SDSRV). Vol 68. Berlin: Erich Schmidt Verlag; 2018: 9-38

    Primärprävention als sozialpolitische Aufgabe: Bedeutung und Entwicklung

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    Gerlinger T. Primärprävention als sozialpolitische Aufgabe: Bedeutung und Entwicklung. In: Rolfs C, Bundestagung des deutschen Sozialrechtsverbandes e.V, eds. Gesundheit als Aufgabe des Sozialrechts. Schriftenreihe des Deutschen Sozialrechtsverbandes . Vol 67. Berlin: Erich Schmidt Verlag; 2018: 9-25

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed

    Measurement of the C 12 (C 12,p) Na 23 cross section near the Gamow energy

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    The fusion reaction C12(C12,p)Na23 has been studied from E=2.00 to 4.00 MeV by particle spectroscopy. The data reveal broad resonances above E=3.00 MeV and are compatible with previously reported resonance structure around E=2.1 MeV. The data were limited at low energies by low count rates as well as possible background contributions. This experiment extends the previously achieved low-energy measurement by charged particle spectroscopy to 2 MeV, which corresponds to the high-energy side of the astrophysically relevant temperature. Present knowledge of level structures and nonresonant contribution cannot explain the results of the present experiment, which may change the C12+C12 reaction rate significantly. Despite the progress decreasing the low-energy limit, any extrapolation into the astrophysical energy range remains highly uncertain based on available experimental data

    Mitomycin C in highly myopic eyes - Author reply

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    Ophthalmology. 2005 Feb;112(2):208-18; discussion 219. Mitomycin C modulation of corneal wound healing after photorefractive keratectomy in highly myopic eyes. Gambato C, Ghirlando A, Moretto E, Busato F, Midena E. SourceRefractive Surgery Service and Antimetabolite Therapy Research Unit, Department of Ophthalmology, University of Padova, Padova, Italy. Abstract PURPOSE: To evaluate the role of topical mitomycin C in corneal wound healing (CWH) after photorefractive keratectomy (PRK) in highly myopic eyes. DESIGN: Prospective, double-masked, randomized clinical trial. PARTICIPANTS: Seventy-two eyes of 36 patients affected by high (>7 diopters) myopia. METHODS: In each patient, one eye was randomly assigned to PRK with intraoperative topical 0.02% mitomycin C application, and the fellow eye was treated with a placebo. Postoperatively, mitomycin C-treated eyes received artificial tears (3 times daily, tapered in 3 months), whereas the fellow eye was treated with fluorometholone sodium 2% and artificial tears (3 times daily, tapered in 3 months). MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), contrast sensitivity, manifest refraction, and biomicroscopy. Contrast sensitivity was determined using the Pelli-Robson chart. Corneal confocal microscopy documented CWH. RESULTS: Mean follow-up was 18 months (range, 12-36). No side effects or toxic effects were documented. At 12-month follow-up examination, UCVAs (logarithm of the minimum angle of resolution) were 0.4+/-0.48 and 0.5+/-0.53 (P = .03) in mitomycin C-treated eyes and corticosteroid-treated eyes, respectively. At 1 year, corneal haze developed in 20% of corticosteroid-treated eyes, versus 0% of mitomycin C-treated eyes. At 12, 24, and 36 months, corneal confocal microscopy showed activated keratocytes and extracellular matrix significantly more evident in untreated eyes (Ps = 0.004, 0.024, and 0.046, respectively). CONCLUSION: Topical intraoperative application of 0.02% mitomycin C can reduce haze formation in highly myopic eyes undergoing PRK. Comment in Ophthalmology. 2006 Feb;113(2):357; author reply 357-8
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