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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
Buffon, Jefferson et l'homme américain
No full textBUFFON, JEFFERSON AND THE AMERICAN MAN Summary. — Jacques Roger tackles the lively debate stirred up in the United States by Buffon's unflattering — and europocentric — description of the American Indian. He analyses how Thomas Jefferson, a man of science and admirer of Buffon, refutes the naturalist's theory by using his own approach and contradicting each of his arguments based on « the climate theory ». The author also shows that beyond this scientific debate, Jefferson, the politician, concerned by the situation of the American Black, defends at the same time the notion of an « universal human nature », a notion which was to inspire political philosophy.Résumé. — Jacques Roger aborde le vif débat suscité aux États-Unis par la description peu flatteuse — et européocentrique — de l'Indien américain par Buffon. Il analyse comment Thomas Jefferson, homme de science et admirateur de Buffon, réfute le naturaliste en empruntant sa démarche et en contredisant chacun de ses arguments basés sur « la théorie des climats ». L'auteur montre aussi qu'au-delà de ce débat scientifique, Jefferson, homme politique, préoccupé par la situation du Noir américain, défend en même temps la notion d'une « nature humaine universelle », notion qui doit inspirer la philosophie politique.Roger Jacques. Buffon, Jefferson et l'homme américain. In: Bulletins et Mémoires de la Société d'anthropologie de Paris, Nouvelle Série. Tome 1 fascicule 3-4, 1989. pp. 57-65
Haller et Buffon : à propos des Réflexions/Haller and Buffon : concerning the Reflexions
No full textSUMMARY. — This paper aims to throw light on the controversial issue of A. von Haller's alleged « conversion » from epigenesis to preformation. This « conversion » is usually linked to the reaction of the Swiss scholar to the publication of Buffon' s theory of generation (1749). A close study of the texts published by the author of the Physiology on this occasion reveals that, far from having adopted the theory of preformation, he continued to defend epigenesis in a moderate form, a view which was not so different from that held at the same time by Buffon's associate, J. T. Needham.RÉSUMÉ. — On tente ici de faire le point sur une question très discutée, celle de la prétendue « conversion » de A. von Haller de l'épigenèse à la préformation ; « conversion » qui est généralement liée à la « réaction » du savant suisse à la publication de la théorie de la génération de Buffon (1749). Or, une analyse approfondie des textes publiés par l'auteur de la Physiologie à cette occasion montre que, loin d'avoir adopté la théorie de la préformation, le savant bernois a continué à professer une épigenèse modérée qui n'était pas très éloignée de celle défendue, à la même époque, par le compagnon de Buffon, J. T. Needham.Cherni Amor. Haller et Buffon : à propos des Réflexions/Haller and Buffon : concerning the Reflexions. In: Revue d'histoire des sciences, tome 48, n°3, 1995. Les sciences de la vie au Siècle des Lumières. /In memoriam Roselyne Rey pp. 267-306
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
[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
Rhetoric and natural history: buffon in polemical and literary context
No full textThis book examines the rhetorical dimension of eighteenth-century natural history. It focuses on the French naturalist and literary stylist Georges-Louis Leclerc de Buffon, author of the bestselling multi-volume Histoire naturelle (1749-1789). Natural history as Buffon and his contemporaries knew it remains a fascinating object of study for its breadth, its cultural openness, and its disorderly energy. Rhetoric here is understood as a set of techniques for attracting and persuading an audience. As a contribution both to literary studies and to the history of science, Rhetoric and natural history adds to our understanding of the intellectual culture of the French Enlightenment. Acknowledgment Abbreviations Introduction 1 Style 2 Final causes 3 The chain of being 4 Systems and theories 5 Mathematics 6 Nominalism Conclusion List of works cited Inde
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
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