131,369 research outputs found
A reflection on modelling and examination of paramagnetic molecules for magnetic storage and molecular spintronics
No full textParamagnetic molecules featuring preferred orientation of their magnetic moments (magnetic anisotropy, single-molecule magnets, SMMs) are quite promising candidates for use in electronic devices like data storage and quantum computers (q-bits). In 2013, the authors published two papers on FeIIX2 with pseudolinear cores (J. M. Zadrozny, M. Atanasov, A. M. Bryan, C.-Y. Lin, B. D. Rekken, P. P. Power, F. Neese, and J. R. Long, Chem. Sci., 2013, 4, 125–138, https://doi.org/10.1039/C2SC20801F and M. Atanasov, J. M. Zadrozny, J. R. Long and F. Neese, Chem. Sci., 2013,4, 139–156, https://doi.org/10.1039/C2SC21394J). Combining computational tools with ab initio ligand field theory, design principles have been formulated to afford predictions of SMM prior to their later synthesis. These efforts resulted in a linear CoIIC2 SMM with magnetic anisotropy, the maximum possible for a 3d complex
MeSH term explosion and author rank improve expert recommendations
No full textInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
Chemistry and Quantum Mechanics in 2019: Give Us Insight and Numbers
No full textThis Perspective revisits Charles Coulson's famous statement from 1959 "give us insight not numbers" in which he pointed out that accurate computations and chemical understanding often do not go hand in hand. We argue that today, accurate wave function based first-principle calculations can be performed on large molecular systems, while tools are available to interpret the results of these calculations in chemical language. This leads us to modify Coulson's statement to "give us insight and numbers". Examples from organic, inorganic, organometallic and surface chemistry as well as molecular magnetism illustrate the points made
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
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
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
Scholarly Communication and Publishing Lunch and Learn Talk #11: The ULS Open Access Author Fee Fund
No full textAt the May 2014 talk, you will learn about the ULS Open Access Author Fee Fund--what it is, why we do it, how it works, and how the program is going so far
Estudo de supercondutores em espaços curvos: a abordagem de Atanasov para o acoplamento da teoria de Ginzburg-Landau e a teoria da relatividade geral
No full textEm um artigo recente, Victor Atanasov [Physica B, 517(2017)] propôs um acoplamento entre o parâmetro de ordem supercondutor e a geometria do espaço-tempo. Em uma versão estendida de Ginzburg-Landau (TGL). Nesta versão, a curvatura desempenha um papel de um potencial químico efetivo. Verificou-se que o parâmetro de teoria de Ginzburg-Landau, κ, pode ser afetado pela gravidade, de maneira a mudar um supercondutor de Tipo I para Tipo II e vice-versa. Além disso, se a curvatura do espaço-tempo for suficientemente negativa, a supercondutividade é destruída. Em nosso trabalho, no âmbito da TGL estendida de Atanasov, estudamos os efeitos de um campo gravitacional nos vórtices de um supercondutor tipo II próximo à temperatura de transição. O trabalho consiste em investigar se a perturbação gravitacional é suficiente para modificar o estado supercondutor. Minimizamos a energia do condesado supercondutor proposta na TGL mais o termo proposto por Atanasov, a partir do modelo da teoria de campos de Abelian-Higgs, não minimamente acoplado à gravidade apresentado por Y. Verbin [Phys. Rev. D, 59(1999)]. Estudamos o problema de um campo gravitacional estático. O caso escolhido foi o de um supercondutor nas proximidades de um buraco negro. Descrevemos as equações da TGL e a TGL estendida de Atanasov, de forma necessária para obter as equações de campo de Einstein-Higgs acopladas, que foram posteriormente escritas admissionalmente para se obter uma solução numérica.In a recent article, Victor Atanasov [Physica B, 517(2017)] proposed a coupling between the superconducting order parameter and the geometry of spacetime, in an extended Ginzburg-Landau Theory (GLT). In this verson, the curvature plays an effective role of a chemical potential. It is found that the coherence length and the Ginzburg-Landau parameter of the superconductor are affected by gravity in such a way as to change a superconductor from Type-I to Type-II and vice-versa. Moreover, for a sufficiently negative curvature of space-time the superconductivity is destroyed. In our work, in the framework of Atanasov’s extended GLT, we study the effects of a gravitational field in a vortex dynamics of a Type-II superconductor near the transition temperature. The work consists of investigating whether the perturbation caused by gravitational fields is enough to modify the superconducting state. We minimize the energy of the superconducting Condensate proposed in TGL plus the term proposed by Atanasov, starting from the Abelian-Higgs field theory model, non-minimally coupled to gravity proposed by Y. Verbin [Phys. Rev. D, 59(1999)]. We study a problem of a static gravitational field. The chosen case was that of a superconductor near a black hole. We describe a GLT equations and Atanasov’s extended GLT necessary for obtaining the coupled Einstein-Higgs field equations, that were subsequently written dimensionless form to obtain a numerical solution.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPE
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