1,721,032 research outputs found

    Visual Demonstration Of The Ionic Strength Effect In The Classroom. The Debye-hückel Limiting Law

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    The effects of ionic strength on ions in aqueous solutions are quite relevant, especially for biochemical systems, in which proteins and amino acids are involved. The teaching of this topic and more specifically, the Debye-Hückel limiting law, is central in chemistry undergraduate courses. In this work, we present a description of an experimental procedure based on the color change of aqueous solutions of bromocresol green (BCG), driven by addition of electrolyte. The contribution of charge product (z +|z-|) to the Debye-Hückel limiting law is demonstrated when the effects of NaCl and Na2SO4 on the color of BCG solutions are compared.361187189Atkins, P.W., (1998) Physical Chemistry, , 7th ed., Oxford University Press: OxfordLevine, I.N., (1983) Physical Chemistry, , 2nd ed., McGraw-Hill Book Company: New YorkSilva, C.R., Pereira, R.B., Sabadini, E., (2001) J. Chem. Educ., 78, p. 93

    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

    Variations on the Author

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    “Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship

    Appropriate Similarity Measures for Author Cocitation Analysis

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    We 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

    Dispelling the Myths Behind First-author Citation Counts

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    We conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more sophisticated methods

    Author Index

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    koamabayili/VECTRON-author-checklist: VECTRON author checklist

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    We have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used

    A Revision On The Toms Effect - A Phenomenon In Which Macromolecules Attenuate Turbulence In Liquids [uma Revisão Sobre O Efeito Toms - O Fenômeno Onde Macromoléculas Atenuam A Turbulência Em Um Líquido]

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    It is very well known that the addition of polymers to a liquid increases the shear viscosity of the solution. In other words, the polymer increases the dissipation of the flow energy. Contrarily, in turbulent flow, some particular macromolecules in very low concentration are able to produce large attenuation in the turbulence and thus, decreasing the dissipation of the energy. This article present a brief revision about macroscopic and molecular models used to explain this dynamic effect. Some of the experimental techniques used to quantify the attenuation of the turbulence and the main active substances are also discussed.344658664Kulicke, W.-M., Andreis, M., Gräger, H., Koening, J.L., Köter, M., (1989) Advances in Polymer Science, Polymer Characterization/Polymer Solutions, 89. , Springer- Verlag: BerlimWhite, A., Hemmings, J.A.G., (1976) Em Drag Reduction by Additives: Review and Bibliography, , White, A.Hemmings, J. A. G., eds.BHRA Fluid Engineering: BedfordShenoy, A.V., (1984) Colloid Polym. Sci., 262, p. 319Leuchtag, H.R., (1978) Phys. Today, 31, p. 17Bailey, F.E., Koleske, J.V., (1976) Poly(ethylene oxide), , Academic Press Inc.: New Yorkhttp://en.wikipedia.org/wiki/Turbulence, Veja, por exemplo, em: Acessada em Outubro 2010Screenivasan, K., White, C.M., (2000) J. Fluid Mech., 409, p. 149Goodwin, J.W., Hughes, R.W., (2000) Rheology for Chemists-An Introduction, , The Royal Society of Chemistry: CambridgeMorgan, S.E., McCormick, C.L., (1990) Prog. Polym. Sci., 15, p. 507Virk, P.S., Merrill, E.W., Smith, K.A., (1967) J. Fluid Mech., 30, p. 305Lumley, J.L., (1969) Ann. Rev. Fluid Mech., 1, p. 367Ryskin, G., (1987) Phys. Rev. Lett., 59, p. 2059De Gennes, P.G., (1990) Introduction to Polymer Dynamics, , Cambridge University Press: New YorkA teoria pode ser encontrada em: Landahl (1992) Turbulence and Random Processes in Fluid Mechanics, , M. T.Mollo-Christensen, E., Cambridge University Press: New York, 2 nd edRouse Jr., P.E., (1953) J. Chem. Phys., 21, p. 1272Zimm, B.H., (1956) J. Chem. Phys., 24, p. 269Hershey, H.C., Zakin, J.L., (1967) Chem. Eng. Sci., 22, p. 1847Berman, N.S., (1978) Ann. Rev. Fluid Mech., 10, p. 27Sellin, R.H.J., Hoyt, J.W., Scrivener, O., (1982) J. Hydraul. Res., 20, p. 29Hoyt, J.W., (1966) J. Polym. Sci Polym. Lett., 4, p. 713Peyser, P., Little, R.C., (1971) J. Appl. Polym. Sci., 15, p. 2623Cowan, M.E., Garner, C., Hester, R.D., McCormick, C.L., (2001) J. Appl. Polym. Sci., 82, p. 1222Kenis, P.R., (1971) J. Appl. Polym. Sci., 15, p. 607Ram, A., Finkelstein, E., Elata, C., (1967) I & EC Process Design and Development, 6, p. 309Choi, H.J., Kim, C.A., Jhon, M.S., (1999) Polymer, 40, p. 4527Kim, C.A., Choi, H.J., Sung, J.H., Lee, H.M., Jhon, M.S., (2005) Macromol. Symp., 222, p. 169Cooper-White, J.J., Crooks, R.C., Boger, D.V., (2002) Colloids Surf. A, 210, p. 105Zhang, Y., Schmidt, J., Talmon, Y., Zakin, J.L., (2005) J. Colloid Interface Sci., 286, p. 696Qi, Y.Y., Zakin, J.L., (2002) Ind. Eng. Chem. Res., 41, p. 6326Rodrigues, R.K., Da Silva, M.A., Sabadini, E., (2008) Langmuir, 24, p. 13875Sabadini, E., Francisco, K.R., Bouteiller, L., (2010) Langmuir, 26, p. 1482Bellot, M., Bouteiller, L., (2008) Langmuir, 24, p. 14176Little, R.C., (1971) J. Appl. Polym. Sci., 15, p. 3117Kulik, V.M., (2001) Exp. Fluids, 31, p. 558Kalashnikov, V.N., (1998) J. Non-Newtonian Fluid Mech., 75, p. 209. , Koeltzsch, KQi, Y., Brodkey, R.S., Zakin, J.L., (2003) Exp. Fluids, 34, p. 515Nakken, T., Tande, M., Elgsaeter, A., (2001) J. Non-Newtonian Fluid Mech., 97, p. 1Nakken, T., Tande, M., Nyström, B., (2004) Eur. Polym. J., 40, p. 181Bizotto, V.C., Sabadini, E., (2008) J. Appl. Polym. Sci., 110, p. 1844Sabadini, E., Da Silva, M.A., Carvalho, C.H., Rocha, N.O., (2009) Energy Fuels, 23, p. 4529Sabadini, E., Alkschbirs, M.I., (2002) Exp. Fluids, 33, p. 242Sabadini, E., Alkschbirs, M.I., Bizotto, V.C., De Oliveira, M., (2004) Langmuir, 20, p. 11315Sabadini, E., Alkschbirs, M.I., (2004) J. Phys. Chem. B, 108, p. 1183Sabadini, E., Figueredo, R., (2003) Colloids Surf. A, 215, p. 77Sabadini, E.Francisco, K. R.Pedido de patente protocolado sob número: 018090002768Kitagawa, A., Hishida, K., Kodama, Y., (2005) Exp. Fluids, 38, p. 46
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