1,720,953 research outputs found
Discontinuous molecular dynamics simulation study of polymer collapse
No full textDiscontinuous molecular dynamics simulations were used to study the coil-globule transition of a polymer in an explicit solvent. Two different versions of the model were employed, which are differentiated by the nature of monomer-solvent, solvent-solvent, and nonbonded monomer-monomer interactions. For each case, a model parameter lambda determines the degree of hydrophobicity of the monomers by controlling the degree of energy mismatch between the monomers and solvent particles. We consider a lambda-driven coil-globule transition at constant temperature. The simulations are used to calculate average static structure factors, which are then used to determine the scaling exponents of the system in order to determine the theta-point values lambda(theta) separating the coil from the globule state. For each model we construct coil-globule phase diagrams in terms of lambda and the particle density rho. Additionally, we explore for each model the effects of varying the range of the attractive interactions on the phase boundary separating the coil and globule phases. The results are analyzed in terms of a simple Flory-type theory of the collapse transition. (c) 2006 American Institute of Physics.PT: J; CR: ABRAMS CF, 2002, EUROPHYS LETT, V59, P391 ALDER BJ, 1959, J CHEM PHYS, V31, P459 ALLEN MP, 1987, COMPUTER SIMULATION BAYSAL BM, 2003, MACROMOL THEOR SIMUL, V12, P627 BELOHOREC P, 1997, UNPUB U GUELPH REPOR BIRSHTEIN TM, 1991, MACROMOLECULES, V24, P1554 CHANG RW, 2001, J CHEM PHYS, V114, P7688 CHAPELA GA, 1984, MOL PHYS, V53, P139 CICCOTTI G, 2004, J STAT PHYS, V115, P701 DELAPENA LH, CONDMAT0607527 DELAPENA LH, CONDMAT0607528 DIJKSTRA M, 1994, J CHEM PHYS, V101, P3179 DIJKSTRA M, 1994, PHYS REV LETT, V72, P298 ERPENBECK JJ, 1977, STAT MECH B FLORY PJ, 1953, PRINCIPLES POLYM CHE GAN HH, 1998, J CHEM PHYS, V109, P2011 GAN HH, 1999, J CHEM PHYS, V110, P3235 GROSBERG AY, 1994, STAT PHYS MACROMOLEC HSU HP, 2004, MACROMOLECULES, V37, P4658 LI ZM, 2005, LANGMUIR, V21, P7579 LISAL M, 2003, J CHEM PHYS, V119, P4026 LIU JX, 1994, IND ENG CHEM RES, V33, P957 LIVADARU L, 2005, J PHYS CHEM B, V109, P10631 LOWE CP, 2005, J CHEM PHYS, V122 LUNABARCENAS G, 1997, J CHEM PHYS, V107, P10782 NISHIO I, 1979, NATURE, V281, P208 POLSON JM, 1999, PHYS REV E, V60, P3429 POLSON JM, 2000, J CHEM PHYS, V113, P1283 POLSON JM, 2002, J CHEM PHYS, V116, P7244 POLSON JM, 2005, J CHEM PHYS, V122 PORTER JA, 2005, J CHEM PHYS, V122 PRELLBERG T, 2001, J PHYS A-MATH GEN, V34, L599 RAPAPORT DC, 1980, J COMPUT PHYS, V34, P184 RAPAPORT DC, 2003, PHYS REV E 1, V68 SMITH SW, 1997, J COMPUT PHYS, V134, P16 SWISLOW G, 1980, PHYS REV LETT, V44, P796 TAYLOR MP, 2004, J CHEM PHYS, V121, P10757 VASILEVSKAYA VV, 1998, J CHEM PHYS, V109, P5108 ZHOU YQ, 1996, PHYS REV LETT, V77, P2822 ZHOU YQ, 1997, P NATL ACAD SCI USA, V94, P14429 ZHOU YQ, 1999, J MOL BIOL, V293, P917; NR: 41; TC: 0; J9: J CHEM PHYS; PG: 9; GA: 107OVSource type: Electronic(1
Intermolecular potentials in liquid crystals: comparison between simulations and NMR experiments
No full textThe anisotropic intermolecular forces responsible for the orientational ordering in liquid crystals are probed by comparing Monte Carlo (MC) simulations with experimental nuclear magnetic resonance (NMR) results for solutes in nematic liquid crystals. In a special liquid crystal mixture where all long-range interactions are assumed to be minimized, the models for short-range interactions which best fit NMR experimental solute order parameters also best fit solute order parameters from MC simulations of hard ellipsoids. This is taken as an indication that in this special mixture the intermolecular potential is dominated by short-range forces. However, for liquid crystals where long-range interactions are important, simulations of hard ellipsoids with point quadrupoles cannot reproduce even the gross effects observed with experimental NMR data.PT: J; CR: BURNELL EE, 1982, PHYS REV A, V25, P2339 BURNELL EE, 1998, CHEM REV, V98, P2359 CELEBRE G, 1997, MOL PHYS, V92, P1039 DIEHL P, 1974, J MAGN RESON, V14, P260 EMSLEY JW, 1983, MOL PHYS, V49, P1321 EMSLEY JW, 1991, LIQ CRYST, V9, P643 FERRARINI A, 1992, MOL PHYS, V77, P1 KOK MY, 1988, LIQ CRYST, V3, P485 PATEY GN, 1983, CHEM PHYS LETT, V99, P271 PHOTINOS DJ, 1992, J PHYS CHEM-US, V96, P8176 PHOTINOS DJ, 1993, J CHEM PHYS, V98, P10009 POLSON JM, 1996, MOL PHYS, V88, P767 POLSON JM, 1997, PHYS REV E, V55, P4321 SYVITSKI RT, IN PRESS SYVITSKI RT, 1997, CHEM PHYS LETT, V281, P199 TERZIS AF, 1994, MOL PHYS, V83, P847 VANDEREST AJ, 1985, MOL PHYS, V56, P161 VANDEREST AJ, 1987, MOL PHYS, V60, P397 VANDEREST AJ, 1988, J CHEM PHYS, V89, P4657 VANDEREST AJ, 1988, J CHEM SOC F2, V84, P1095 ZIMMERMAN DS, 1993, MOL PHYS, V78, P687; NR: 21; TC: 7; J9: INT J MOD PHYS C; PG: 11; GA: 222HPSource type: Electronic(1
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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