305,505 research outputs found
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
Dispelling the Myths Behind First-author Citation Counts
No full textWe 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
Nitroxide paramagnet-induced para-ortho conversion and nuclear spin relaxation of H-2 in organic solvents
No full textThe kinetics of para-ortho conversion and nuclear spin relaxation of H-2 in chloroform-d(1), were investigated in the presence of nitroxides as paramagnetic catalysts. The back conversion from parahydrogen (p-H-2) to ortho-hydrogen (o-H-2) was followed by NMR by recording the increase in the intensity of the signal of o-H-2 at regular intervals of time. The nitroxides proved to be hundreds of times more effective at inducing relaxation among the spin levels of o-H-2 than they are in bringing about transitions between p-H-2 and the levels of o-H-2. The value of the encounter distance d between H-2 and the paramagnetic molecule, calculated from the experimental bimolecular conversion rate constant k(0), using the Wigner theory of para-ortho conversion, agrees perfectly with that calculated from the experimental relaxivity R-1 using the force free diffusion theory of spin-lattice relaxation
Author, publisher and bookseller : a tripartite synergy in Nigerian book industry
No full textThis work is about the roles of Author, Publisher and Bookseller in Book development in
Nigeria. The paper started by delving into the history of Book Publishing in Nigeria after
which it proceeded by defining who an author, a publisher, and a bookseller is and
expatiated on the indispensable roles of these key actors in Nigerian Book Industry and in
the emerging Information Society. Furthermore, the various constraints to book
development were identified while the paper advised on how the Book Industry can be
further promoted in Nigeria. However, the paper concluded and made recommendations
on how the Book sector can help in enhancing scholarship in the country
Pyridine ylide formation by capture of phenylchlorocarbene and tert-butylchlorocarbene. Reaction rates of an alkylchlorocarbene by laser flash photolysis
No full textPT: J; CR: BARCUS RL, 1986, J AM CHEM SOC, V108, P3928 CHATGILIALOGLU C, 1982, J AM CHEM SOC, V104, P5124 GOULD IR, 1985, TETRAHEDRON, V41, P1587 GRILLER D, 1984, J AM CHEM SOC, V106, P2227 LIU MTH, 1985, TETRAHEDRON LETT, V26, P3071 MOSS RA, 1981, TETRAHEDRON LETT, V38, P3749 SOUNDARARAJAN N, IN PRESS J AM CHEM S SOUNDARARAJAN N, IN PRESS TETRAHEDRON SOUNDARARAJAN N, UNPUB TURRO NJ, 1985, J ORG CHEM, V50, P4417 TURRO NJ, 1987, J AM CHEM SOC, V109, P2101 ZUGRAVESCU I, 1976, N YLID CHEM; NR: 12; TC: 144; J9: J AMER CHEM SOC; PG: 2; GA: P5279Source type: Electronic(1
Infrared spectroscopy of endohedral HD and D2 in C60
No full textWe report on the dynamics of two hydrogen isotopomers, D-2 and HD, trapped in the molecular cages of a fullerene C-60 molecule. We measured the infrared spectra and analyzed them using a spherical potential for a vibrating rotor. The potential, vibration-rotation Hamiltonian, and dipole moment parameters are compared with previously studied H-2@C-60 parameters [M. Ge, U. Nagel, D. Hiivonen, T. Room, S. Mamone, M. H. Levitt, M. Carravetta, Y. Murata, K. Komatsu, J. Y.-C. Chen, and N. J. Turro, J. Chem. Phys. 134, 054507 (2011)]. The isotropic part of the potential is similar for all three isotopomers. In HD@C-60, we observe mixing of the rotational states and an interference effect of the dipole moment terms due to the displacement of the HD rotation center from the fullerene cage cente
[Report to Chief J. E. Curry, by an unknown author #2]
No full textReport to Chief J. E. Curry, by an unknown author. The report contains a list of officers who gave depositions to the United States Attorney
Propriedades físico-químicas de um surfactante gêmeo aniônico e de suas misturas binárias com surfactantes convencionais
No full textTCC (graduação) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas, Curso de Química.O surfactante do tipo dimérico ou gêmeo, di-n-decil-1,6-hexil bisfosfato dissOdico (10-6-10), foi preparado a partir da reação do bistetrametilamônio decilfosfato corn 1,6-dibromohexano. Na presença de tampão borato 0,01 moll-1 , pH 9,0, o valor da concentração micelar critica (crnc), obtido por condutimetria para o 10-6-10 foi de 0,0015 moll-1 , que é aproximadamente 100 vezes menor que aquele obtido para o surfactante monomeric° decilfosfato (0,120 moll-1 ) nas mesmas condições de pH. Estes resuitados evidenciam as melhores propriedades tensoativas dos surfactantes diméricos. Foram determinados os valores de cmc para as misturas binarias de 10-6-10 com o dodecilsulfato de sódio, SDS, e com a sulfobetaina ntetradecil- N,N-dirnetil-3-arn6nio-1-propanosulfonato, SB3-14, em função da fração molar de 10-6-10. O sistema 10-6-10/SDS mostrou um comportamento de mistura ideal, enquanto o sistema 10-6-10/SB3-14 mostrou sinergismo na formação da micela mista. Usando a teoria da solução regular determinou-se um valor de -4,7 para o parâmetro de interação molecular, 13. Este efeito tem sido racionalizado em termos de interações eletrostáticas entre os grupos amônio e fosfato nos dois surfactantes. Foram determinados os valores de pH aparente e de micropolaridade para misturas dos surfactantes gêmeo 10-6-10 e a suifobetaina SB3-14, como uma função da fração molar do sufactante gêmeo. Os valores de pH aparente foram estimados utilizando como indicador o brometo de 1- dodecil-4-piridiniumaldoxima (DPA). As medidas de micropolaridade foram estimadas a partir da razão das intensidades de fluorescência das bandas 1 e III do pireno monomeric°. 0 enriquecimento no conteúdo do surfactante gêmeo (ani6nico) na micela mista aumenta a densidade de carga negativa na superfície micelar, diminuindo assim a concentração do ion OH - devido a repulsão eletrostática deste com a superfície, diminuindo o pH aparente e aumentando a polaridade no sitio de solubilização do pireno. O número de agregação médio para o surfactante gêmeo foi avaliado (método de Turro) nas concentrações de 3, 10 e 67 vezes a cmc. Os valores encontrados foram 12, 21 e 48 respectivamente
[Report to Chief J. E. Curry, by an unknown author #1]
No full textReport to Chief J. E. Curry, by an unknown author. The report contains a list of officers who gave depositions to the United States Attorney
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