The Experts below are selected from a list of 42690 Experts worldwide ranked by ideXlab platform
Allan Parsons - One of the best experts on this subject based on the ideXlab platform.
-
academic liaison librarianship curatorial pedagogy or pedagogical curation
Ariadne, 2010Co-Authors: Allan ParsonsAbstract:In the 1990s and early 2000s, the liaison model in academic librarianship developed around three roles: reference services, instructional services and collection development, with collection management being the core around which the other two roles are organised. This liaison model of academic librarianship is closely tied to the model of the academic library as the gateway to the collection and hence to the knowledge encoded within it. However, these Explicit Functional roles (reference, instruction, collection) mask a communicational role which is likely to be of far greater importance going forward: relationship building. The building of relationships is the nexus or linking principle of an engagement model. The engagement model enables an emerging field of practice to be recognised, whereby those engaged in liaison may develop their roles through an ever-deepening engagement with learning practices at several levels: the development of academic learning, teaching and research; organisational learning and organisational development; and institutional learning and institutional development. The practical implications of an engagement model for higher education institutions are explored, from the perspective of the University of Westminster.
-
academic liaison librarianship curatorial pedagogy or pedagogical curation
Social Science Research Network, 2010Co-Authors: Allan ParsonsAbstract:In the 1990s and early 2000s, the liaison model in academic librarianship has developed around three roles: reference services, instructional services and collection development, collection development being the core around which the other two roles are organised. This liaison model of academic librarianship is closely tied to the model of the academic library as the gateway to the collection and hence to the knowledge encoded within it. However, these Explicit Functional roles (reference, instruction, collection) mask a communicational role which is likely to be of far greater importance going forward: relationship building. The building of relationships is the nexus or linking principle of an engagement model. The engagement model enables an emerging field of practice to be recognised, whereby those engaged in liaison may develop their roles through an ever-deepening engagement with learning practices at several levels: academic learning, teaching and research; professional learning and development; organisational learning and organisational development; and institutional learning and institutional development. The practical implications of an engagement model for higher education institutions are explored, from the perspective of the University of Westminster.
Naoto Umezawa - One of the best experts on this subject based on the ideXlab platform.
-
Explicit density Functional exchange potential with correct asymptotic behavior
Physical Review A, 2006Co-Authors: Naoto UmezawaAbstract:In this paper, a density-Functional exchange potential is proposed. The suggested exchange potential reproduces the correct asymptotic behavior of finite systems: -1/r, without significant increase in computational costs over a local-density approximation. Our model exchange potential, which is an Explicit Functional of a density and the gradient of the density, is given by a hybridization procedure of a Hartree potential and the homogeneous electron gas limit of the exchange potential. Since the Hartree potential behaves as N/r in an asymptotic region with N number of electrons, it is utilized for achieving the correct -1/r asymptotic behavior in our model exchange potential. We found that the suggested exchange potential can yield very good estimates for the ionization potential of atoms and ions from the highest occupied orbital energies.
-
Explicit density Functional exchange potential with correct asymptotic behavior
Physical Review A, 2006Co-Authors: Naoto UmezawaAbstract:In this paper, a density-Functional exchange potential is proposed. The suggested exchange potential reproduces the correct asymptotic behavior of finite systems: $\ensuremath{-}1∕r$, without significant increase in computational costs over a local-density approximation. Our model exchange potential, which is an Explicit Functional of a density and the gradient of the density, is given by a hybridization procedure of a Hartree potential and the homogeneous electron gas limit of the exchange potential. Since the Hartree potential behaves as $N∕r$ in an asymptotic region with $N$ number of electrons, it is utilized for achieving the correct $\ensuremath{-}1∕r$ asymptotic behavior in our model exchange potential. We found that the suggested exchange potential can yield very good estimates for the ionization potential of atoms and ions from the highest occupied orbital energies.
Alejandro Cabezascruz - One of the best experts on this subject based on the ideXlab platform.
-
phyloproteomic and Functional analyses do not support a split in the genus borrelia phylum spirochaetes
BMC Evolutionary Biology, 2019Co-Authors: Agustin Estradapena, Alejandro CabezascruzAbstract:Background The evolutionary history of a species is frequently derived from molecular sequences, and the resulting phylogenetic trees do not include Explicit Functional information. Here, we aimed to assess the Functional relationships among bacteria in the Spirochaetes phylum, based on the biological processes of 42,489 proteins in reference proteomes of 34 Spirochaetes species. We tested the hypothesis that the species in the genus Borrelia might be sufficiently different to warrant splitting them into two separate genera.
-
phyloproteomic and Functional analyses do not support a split in the genus borrelia phylum spirochaetes
BMC Evolutionary Biology, 2019Co-Authors: Agustin Estradapena, Alejandro CabezascruzAbstract:The evolutionary history of a species is frequently derived from molecular sequences, and the resulting phylogenetic trees do not include Explicit Functional information. Here, we aimed to assess the Functional relationships among bacteria in the Spirochaetes phylum, based on the biological processes of 42,489 proteins in reference proteomes of 34 Spirochaetes species. We tested the hypothesis that the species in the genus Borrelia might be sufficiently different to warrant splitting them into two separate genera. A detrended canonical analysis demonstrated that the presence/absence of biological processes among selected bacteria contained a strong phylogenetic signal, which did not separate species of Borrelia. We examined the ten biological processes in which most proteins were involved consistently. This analysis demonstrated that species in Borrelia were more similar to each other than to free-life species (Sediminispirochaeta, Spirochaeta, Sphaerochaeta) or to pathogenic species without vectors (Leptospira, Treponema, Brachyspira), which are highly divergent. A dendrogram based on the presence/absence of proteins in the reference proteomes demonstrated that distances between species of the same genus among free-life or pathogenic non-vector species were higher than the distances between the 19 species (27 strains) of Borrelia. A phyloproteomic network supported the close Functional association between species of Borrelia. In the proteome of 27 strains of Borrelia, only a few proteins had evolved separately, in the relapsing fever and Lyme borreliosis groups. The most prominent Borrelia proteins and processes were a subset of those also found in free-living and non-vectored pathogenic species. In addition, the Functional innovation (i.e., unique biological processes or proteins) of Borrelia was very low, compared to other genera of Spirochaetes. We found only marginal Functional differences among Borrelia species. Phyloproteomic networks that included all pairwise combinations between species, proteins, and processes were more effective than other methods for evaluating the evolutionary relationships among taxa. With the limitations of data availability, our results did not support a split of the arthropod-transmitted spirochaetes into the proposed genera, Borrelia and Borreliella.
Juanpablo Ortega - One of the best experts on this subject based on the ideXlab platform.
-
nonlinear memory capacity of parallel time delay reservoir computers in the processing of multidimensional signals
Neural Computation, 2016Co-Authors: Lyudmila Grigoryeva, Julie Henriques, Laurent Larger, Juanpablo OrtegaAbstract:This letter addresses the reservoir design problem in the context of delay-based reservoir computers for multidimensional input signals, parallel architectures, and real-time multitasking. First, an approximating reservoir model is presented in those frameworks that provides an Explicit Functional link between the reservoir architecture and its performance in the execution of a specific task. Second, the inference properties of the ridge regression estimator in the multivariate context are used to assess the impact of finite sample training on the decrease of the reservoir capacity. Finally, an empirical study is conducted that shows the adequacy of the theoretical results with the empirical performances exhibited by various reservoir architectures in the execution of several nonlinear tasks with multidimensional inputs. Our results confirm the robustness properties of the parallel reservoir architecture with respect to task misspecification and parameter choice already documented in the literature.
-
nonlinear memory capacity of parallel time delay reservoir computers in the processing of multidimensional signals
arXiv: Neural and Evolutionary Computing, 2015Co-Authors: Lyudmila Grigoryeva, Julie Henriques, Laurent Larger, Juanpablo OrtegaAbstract:This paper addresses the reservoir design problem in the context of delay-based reservoir computers for multidimensional input signals, parallel architectures, and real-time multitasking. First, an approximating reservoir model is presented in those frameworks that provides an Explicit Functional link between the reservoir parameters and architecture and its performance in the execution of a specific task. Second, the inference properties of the ridge regression estimator in the multivariate context is used to assess the impact of finite sample training on the decrease of the reservoir capacity. Finally, an empirical study is conducted that shows the adequacy of the theoretical results with the empirical performances exhibited by various reservoir architectures in the execution of several nonlinear tasks with multidimensional inputs. Our results confirm the robustness properties of the parallel reservoir architecture with respect to task misspecification and parameter choice that had already been documented in the literature.
Adam Wasserman - One of the best experts on this subject based on the ideXlab platform.
-
non additive non interacting kinetic energy of rare gas dimers
Journal of Chemical Physics, 2018Co-Authors: Kaili Jiang, Jonathan Nafziger, Adam WassermanAbstract:Approximations of the non-additive non-interacting kinetic energy (NAKE) as an Explicit Functional of the density are the basis of several electronic structure methods that provide improved computational efficiency over standard Kohn-Sham calculations. However, within most fragment-based formalisms, there is no unique exact NAKE, making it difficult to develop general, robust approximations for it. When adjustments are made to the embedding formalisms to guarantee uniqueness, approximate Functionals may be more meaningfully compared to the exact unique NAKE. We use numerically accurate inversions to study the exact NAKE of several rare-gas dimers within partition density Functional theory, a method that provides the uniqueness for the exact NAKE. We find that the NAKE decreases nearly exponentially with atomic separation for the rare-gas dimers. We compute the logarithmic derivative of the NAKE with respect to the bond length for our numerically accurate inversions as well as for several approximate NAKE Functionals. We show that standard approximate NAKE Functionals do not reproduce the correct behavior for this logarithmic derivative and propose two new NAKE Functionals that do. The first of these is based on a re-parametrization of a conjoint Perdew-Burke-Ernzerhof (PBE) Functional. The second is a simple, physically motivated non-decomposable NAKE Functional that matches the asymptotic decay constant without fitting.
-
non additive non interacting kinetic energy of rare gas dimers
arXiv: Chemical Physics, 2017Co-Authors: Kaili Jiang, Jonathan Nafziger, Adam WassermanAbstract:Approximations of the non-additive non-interacting kinetic energy (NAKE) as an Explicit Functional of the density are the basis of several electronic structure methods that provide improved computational efficiency over standard Kohn-Sham calculations. However, within most fragment-based formalisms, there is no unique exact NAKE, making it difficult to develop general, robust approximations for it. When adjustments are made to the embedding formalisms to guarantee uniqueness, approximate Functionals may be more meaningfully compared to the exact unique NAKE. We use numerically accurate inversions to study the exact NAKE of several rare-gas dimers within Partition Density Functional Theory, a method that provides the uniqueness for the exact NAKE. We find that the NAKE decreases nearly exponentially with atomic separation for the rare gas dimers. We compute the logarithmic derivative of the NAKE with respect to the bond length for our numerically accurate inversions as well as for several approximate NAKE Functionals. We show that standard approximate NAKE Functionals do not reproduce the correct behavior for this logarithmic derivative, and propose two new NAKE Functionals that do. The first of these is based on a re-parametrization of a conjoint PBE Functional. The second is a simple, physically-motivated non-decomposable NAKE Functional that matches the asymptotic decay constant without fitting.
