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Buffon needle method of track counting
No full textA new technique of quantitative track counting, the Buffon needle method, is advanced. It is based on random sampling of the solid state track recorder (SSTR) surface. This new method extends quantitative track scanning to track densities well up into the track pile-up regime. It is shown that the Buffon needle method possesses a reduced dependence upon both track density nonuniformity and track size distribution. Sources of experimental error arising in the Buffon needle method are assessed. The validity of the Buffon needle method is demonstrated down to at least the 10% uncertainty level (1sigma) by manual sampling of high fission track density mica SSTR observed with scanning electron microscopy
Hydrogenation And Isomerization Of 1-hexene With Ru3(co)9(pph2ch2ch2 Si(ome)3)3 Immobilized In Silica Matrices Via The Sol-gel Method
No full textRu3(CO)9(PPh3)3 and Ru3(CO)9(PPh2CH2CH2 Si(OMe)3)3 have been heterogenized in silica matrices by the sol-gel method. Gels prepared with Ru3(CO)9(PPh2CH2CH2 Si(OMe)3)3 were tested in the hydrogenation and isomerization of 1-hexene. At H2-pressures of 16psi in repeated runs (15h, 90°C) turnover numbers for 1-hexene hydrogenation were between 380 and 460. Isomerization products were trans-2-hexene, cis-2-hexene and trans-3-hexene. No cis-3-hexene, 2-methyl-1-pentene and 2-methylpentane were found. Leaching of ruthenium in each run was around 0.05% of ruthenium present in the original gel. UV-VIS and FT-IR spectra of the pure cluster compounds and the gels before and after the catalytic reactions showed that during the gel preparation some Ru3 units remain intact, but are cleaved when the gel is heated under vacuum or used in catalytic hydrogenation reactions. © 2002 Elsevier Science B.V. All rights reserved.1851-2187194Robertson, J., Webb, G., (1974) Proc. Royal Soc. London A, 341, p. 383Kuznetsov, V.L., Bell, A.T., Yermakov, Y.I., (1980) J. Catal., 65, p. 374Sanchez-Delgado, R.A., Duran, I., Montfort, J., Rodriguez, E., (1981) J. Mol. Catal., 11, p. 193Evans, J., Gracey, B.P., (1982) J. Chem. Soc., Dalton Trans., p. 1123Theolier, A., Choplin, A., D'Ornelas, L., Basset, J.-M., Zanderighi, G., Ugo, R., Psaro, R., Sourisseau, C., (1983) Polyhedron, 2, p. 119Evans, J., McNulty, G.S., (1984) J. Chem. Soc., Dalton Trans., p. 1123Binsted, N., Evans, J., Neville Greaves, G., Price, R.J., (1989) Organometallics, 8, p. 613Doi, Y., Yokota, A., Miyake, H., Soga, K., (1984) Inorg. Chim. Acta, 90, pp. L7Kiiski, U., Pakkanen, T.A., Krause, O., (1989) J. Mol. Catal., 50, p. 143Lopez, T., Bosch, P., Asomoza, M., Gomez, R., (1992) J. Catal., 133, p. 247Lopez, T., Herrera, L., Gomez, R., Zou, W., Robinson, K., Gonzalez, R.D., (1992) J. Catal., 136, p. 621Lopez, T., Herrera, L., Mendez-Vivar, J., Bosch, P., Gomez, R., Gonzalez, R.D., (1992) J. Non Cryst. Solids, 147-148, p. 773Mikuzami, F., Niwa, S., Okhawa, S., Katayama, A., (1993) Stud. Surf. Sci. Catal., 78, p. 337Kluson, P., Had, J., Belohlav, Z., Cerveny, L., (1997) Appl. Catal. A: Gen., 149, p. 331Moggi, P., Predieri, G., Di Silvestri, F., Ferretti, A., (1999) Appl. Catal. A: Gen., 182, p. 257Dallmann, K., Buffon, R., (2001) J. Mol. Catal. A: Chem., 172, p. 81Niebergall, V.W., (1962) Makromol. Chem., 52, p. 218Loy, D.A., Jamison, G.M., Baugher, B.M., Myers, S.A., Assink, R.A., Shea, K.J., (1996) Chem. Mater., 8, p. 656Candlin, J.P., Joshi, K.K., Thompson, D.T., (1966) Chem. Ind., 19, p. 1960Dallmann, K., Buffon, R., (2000) Catal. Commun., 1, p. 9Teixeira, S., Dallmann, K., Schuchardt, U., Buffon, R., (2002) J. Mol. Catal. A: Chem., , in pressBrinker, C.J., Scherer, G.W., (1990) Sol-Gel Science, p. 522. , Academic Press, San DiegoWiberg, K.B., Wasserman, D.J., (1981) J. Am. Chem. Soc., 103, p. 6563Rogers, D.W., Crooks, E., Dejroongruang, K., (1987) J. Chem. Thermodyn., 19, p. 1209Tyler, D.R., Levenson, R.A., Gray, H.B., (1978) J. Am. Chem. Soc., 100, p. 788
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
[Illustrations de Histoire naturelle générale et particulière servant de suite à la théorie de la Terre et d'introduction à l'histoire des minéraux]. Supplément, tome premier / Georges-Louis Leclerc Buffon, aut. du texte
No full textComprend : Frontispice : Georges Louis Le Clerc, Comte de Buffon, intendant du jardin du Roy et des Académies Française et des Sciences, de celles de Londres, d'Edimbourg et de Berlin / Drouais pinxit 1761, C. Baron grav., Mr Drouais direxit. [Cote :13915] ; Page de titre. [Cote :13916.A] ; Bandeau, P1 : Histoire naturelle. Introduction à l'histoire des minéraux. Des éléments. Première partie / De Sève dess., R. Delaunay grav. [Cote :13917.A]Thème : Sciences de la natureIllustratio
Buffon got it straight
No full textIt has long been known that the Buffon needle experiment can be used to estimate [pi]. This raises a question which we investigate in this paper, linking statistics and geometry: how should a grid be laid out in order to give a tight estimator of [pi]? We study four grids: Buffon's single grid, Laplace's double grid, Uspensky's triple grid and the hexagonal tiling. We standardise the grids to have equal "grid density" and find that Buffon's single grid with the maximum length needle provides the tightest estimator of [pi], for the range of needle lengths studied.Buffon needle Information Regular tiling Grid density Asymptotic variance Asymptotic efficiency
Carte declinaisons et inclinaisons de l'aiguille aimantee redigee d'apres la table des obfervations magnetiques faites par les voyageurs depuis l'annee 1775 [cartographic material].
No full text[Dutch ed.]. Map of Australasia showing magnetic variations. Imaginary line joins coastline of Australia and New Guinea.; In bottom right-hand corner: "Explication l'E. avant le chiffre indique la declinaison Est. l'O. la declinaisons Ouest. les inclinaisons n'ont point de lettre."; Probably from: Buffon, Georgre Louis Le Clerc, Comte de. Histoire naturelle des minéraux. Tome V. paris, 1788.; Library holds only 1 sheet, No. 6, of what is believed to be a 2 sheet map.; Shirley, R. Maps in the atlases of the British Library, G.BUFF-1a; Jolly, David C. Antique maps, sea charts, city views, celestial charts & battle plans : price record & handbook for 1986, Anonymous, p. 73.; Also available in an electronic version via the Internet at: http://nla.gov.au/nla.map-rm3104; This item is possibly from Buffon, George Louis Leclerc, comte de, 1707-1788. De algemeene en byzondere natuurlyke historie, met de beschryving van des Konigs kabinet. Door de heeren De Buffon en Daubenton, 1.-17. deel. Te Amsterdam, J.H. Schneider, 1773-1775 (NUC Pre-1956 Imprints, p. 305). Unable to locate map in Histoire naturelle, generale et particuliere. Supplement, Tome quatrieme microform (ANL mc 756 CIHM no. 48872), the source mentioned in Mr Simon Dewez's catalogue, The Printed World, p. 15, Item 111 Buffon. More likely to be from: Histoire naturelle des minéraux
Multiple cutaneous and hepatic infantile hemangiomas having a successful response to propranolol as monotherapy at neonatal period
No full textInfantile hepatic hemangioma (IHH) is a common liver tumors of infancy with a higher incidence in females. Various treatments for infantile hepatic hemangioma such as systemic corticosteroids, interferon-alpha, vincristine and cyclophosphamide have been suggested, though no consensus exists about the first-choice treatment. Recent evidences suggest that propranolol, a nonselective β-blocker, may be effective and safe as first-line therapy for infantile hepatic hemangioma. We report a case of female born at term with a weight of 2.450 g started to develop multiple cutaneous IHs at 10 days of age and presenting concomitant multiple cutaneous and hepatic infantile hemangiomas confirmed on magnetic resonance imaging. Propranolol, used as monotherapy, was started at 14 days of age at a dose of 2 mg/kg/day orally and maintained for 6 months. Patient was monitored in the hospital during first days of treatment with propranolol, and discharged after no side-effects were detected. Hepatic and cutaneous lesions had complete resolution in three months, although the fibro-fatty residuum of largest cutaneous nodule was still palpable at month 6. A further control after 6 months showed no recurrences. Our report case suggests that propranolol can be a safe and effective first-line therapy for neonates with concomitant multiple cutaneous and hepatic infantile hemangiomas
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Collectanées de Winckelmann. — Extraits sur la médecine et l'histoire naturelle.
No full textContient : "Histoire naturelle générale et particulière,... par Buffon." ; "Mémoires de l'Académie des sciences..." ; "Abrégé de toute la médecine pratique." ; "Oeuvres diverses de physique et de mécanique de MM. C. et P. Perrault." ; "Krügers Natur Lehre..." ; "Buffon, Allgemeine Historie der Natur..." ; "Krügers Naturlehre."Numérisation effectuée à partir d'un document original.Numérisation effectuée à partir d'un document de substitution : R 115241
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
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