1,720,957 research outputs found
Differential Structure Of The Hyperbolic Clifford Algebra
No full textThis paper presents a thoughful review of: (a) the Clifford algebra (Formula presented.) of multivecfors which is naturally associated with a hyperbolic space HV ; (b) the study of the properties of the duality product of multivectors and multiforms; (c) the theory of k multivector and l multiform variables multivector extensors over V and (d) the use of the above mentioned structures to present a theory of the parallelism structure on an arbitrary smooth manifold introducing the concepts of covariant derivarives, deformed covariant derivatives and relative covariant derivatives of multivector, multiform fields and extensors fields. © 2014 Springer Basel
Stationary Solutions For Generalized Boussinesq Models In Exterior Domains
No full textWe establish the existence of a stationary weak solution of a generalized Boussinesq model for thermally driven convection in exterior domains. We use the fact that the exterior domain can be approximated by interior domains.199819Drazin, P.G., Reid, W.H., (1981) Hydrodynamic Stability, , Cambridge Univ. PressGilbarg, D., Trudinger, N.S., (1983) Elliptic Partial Differential Equations of Second Order, , Springer, Berlin-HeidelbergHeywood, J.G., The Navier-Stokes equations: On the existence, regularity and decay of solutions (1980) Indiana Univ. Math. J., 29, pp. 639-1181Heywood, J.G., On uniqueness questions in the theory of viscous flow (1976) Acta Math., 136, pp. 61-102Hishida, T., Asymptotic behavior and stability of solutions to exterior convection problem (1994) Nonlinear Anal., 22, pp. 895-925Korenev, N.K., On some problems of convection in a viscous incompressible fluid (1971) Vestnik Leningrad. Univ., (7)(1977) Vestnik Leningrad Univ. Math., 4, pp. 125-137. , English TransLadyzhenskaya, O.A., (1963) The Mathematical Theory of Viscous Incompressible Flow, , Gordon and Breach, New York-LondonLorca, S.A., Boldrini, J.L., Stationary solutions for Generalized Boussinesq models (1996) J. Diff. Eq., 124, pp. 389-406Lorca, S.A., Boldrini, J.L., The initial value Problem for generalized Boussinesq model Nonlinear Anal., , to appearMorimoto, H., On the existence and uniqueness of the stationary solution to the equations of natural convection (1991) Tokyo J. Math., 14, pp. 220-226Oeda, K., Stationary solutions of the heat convection equations in exterior domains (1997) Proc. Japan Acad., 73, pp. 111-115. , Ser. AOeda, K., Remarks on the periodic solution of the heat convection equation in a perturbed annulus domain (1997) Proc. Japan Acad., 73, pp. 21-25. , Ser. AOeda, K., Periodic solutions of the heat convection equation in exterior domain (1997) Proc. Japan Acad., 73, pp. 49-54. , Ser. ARojas-Medar, M.A., Lorca, S.A., The equations of a viscous incompressible chemical active fluid I: Uniqueness and existence of the local solutions (1995) Rev. Mat. Apl., 16, pp. 57-80Rojas-Medar, M.A., Lorca, S.A., The equations of a viscous incompressible chemical active fluid II: Regularity of solutions (1995) Rev. Mat. Apl., 16, pp. 81-9
Superposition Principle And The Problem Of Additivity Of The Energies And Momenta Of Distinct Electromagnetic Fields
No full textIn this paper we prove in a rigorous mathematical way (using the Clifford bundle formalism) that the energies and momenta of two distinct and arbitrary free Maxwell fields (of finite energies and momenta) that are superposed are additive and thus that there is no incompatibility between the principle of superposition of fields and the principle of energy-momentum conservation, contrary to some recent claims. Our proof depends on a noticeable formula for the energy-momentum densities, namely, Riesz formula {black star}τa = 1/2 Fθa{star operator} Ta = frac(1, 2) F θa over(F, ̃), which is valid for any electromagnetic field configuration F, in particular the one satisfying the free Maxwell equation ∂ F= 0. © 2008 Polish Scientific Publishers PWN, Warszawa.62191101Chen, F.C., Linearity of Electromagnetic Field Energy-Momentum (1968) Am. J. Phys., 36, p. 390Cornille, P., (2003) Advanced Electromagnetism and Vacuum Physics, , World Scientific, SingaporeNotte-Cuello, E.A., da Rocha, R., Rodrigues, A., The effective Lorentzian and teleparallel spacetimes generated by a free electromagnetic field (2008) Rep. Math. Phys., 62, pp. 69-89Farlow, S.J., (1982) Partial Differential Equations for Scientists and Engineers, , Wiley, New YorkGauthier, N., What happens to energy and momentum when two oppositely-moving wave pulses overlap? (2003) Am. J. Phys., 71, p. 797Hestenes, D., (1996) Space Time Algebra, , Gordon and Breach, New YorkJenkins, F.A., White, H.E., (1976) Fundamentals of Physics Optics. 4th edition, , McGraw-Hill, New YorkKukhlevsky, S.V., Mechler, M., Csapó, L., Janssens, K., Sameck, O., Enhanced transmission versus localization of light pulse by a subwavelenght metal slit (2004) Phys. Rev. B, 70, p. 195428. , [physics/0408013]Klein, M.V., Furtak, T.E., (1986) Optics. 2nd edition, , Wiley, New YorkS. V. Kukhlevsky: Breaking of Energy Conservation Law: Creating and Destroying of Energy by Subwavelenght Nano Systems, [physics/0610008]S. V. Kukhlevsky: Non Classical Energy-Momentum in Multi-wave Systems: Extra-Energy, Negative-Energy and Annihilation Energy, [physics/0606055]Levine, R.C., False paradox of superposition in electric and acoustic waves (1980) Am. J. Phys., 48, p. 28Mathews, W.N., Superposition and energy conservation for small amplitude mechanical waves (1986) Am. J. Phys., 54, p. 233Parrot, S., (1987) Relativistic Electrodynamics and Differential Geometry, , Springer, New YorkRodrigues Jr., W.A., Algebraic and Dirac-Hestenes spinors and spinor fields (2004) J. Math. Physics, 45, p. 2908. , [math-ph/0212030]Mosna, R.A., Rodrigues Jr., W.A., The bundles of algebraic and Dirac-Hestenes spinor fields (2004) J. Math. Phys, 45, p. 2945. , [math-ph/0212033]Ribarič, M., Šušteršič, L., (1990) Conservation Laws and Open Questions of Classical Electrodynamics, , World Scientific, SingaporeRiesz, M., Clifford Numbers and Spinors: with Riesz's Private Lectures to E. Folke Bolinder and a Historical Review by Pertti Lounesto (1993) Fundamental Theories of Physics, 54. , Springer, BerlinRodrigues, W.A., Capelas de Oliveira, E., The Many Faces of Maxwell, Dirac and Einstein Equations. A Clifford Bundle Approach (2007) Lecture Notes in Physics, 722. , Springer, HeidlebergRowland, D.R., Pask, C., The missing wave momentum mystery (1999) Am. J. Phys., 67, p. 378Sachs, R.K., Wu, H., (1977) General Relativity for Mathematicians, , Springer, New YorkThirring, W., (1980) Classical Field Theory, 2. , Springer, New YorkStrong, J., (1958) Concepts of Classical Optics, , Fremann, San FranciscoWelti, R., Light transmission through two slits: the young experiment revisited (2006) J. Opt. A: Pure Appl. Opt., 8, p. 606Wu, T.T., Spreading of electromagnetic pulses (1985) J. Appl. Phys., 58, p. 206
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Full text linkWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe 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
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