29,256 research outputs found
Rudolf Serkin: A Life
Pianist Rudolf Serkin, a virtuosic solo performer and chamber musician, captivated music lovers the world over for much of the twentieth century. Although he acquired a large and devoted public following, Serkin preferred to keep out of the spotlight, instead directing attention toward the music he loved. Dedicated to disseminating European classical music in America, Serkin became a committed teacher and director of major musical institutions. Rudolf Serkin: A Life, the first biography of this influential figure, offers an insightful analysis of Serkin\u27s role in shaping American musical values and provides a rare glimpse into the life story of this intense performer and elusive man
Does the h-index have predictive power?
Bibliometric measures of individual scientific achievement are of particular
interest if they can be used to predict future achievement. Here we report
results of an empirical study of the predictive power of the h-index compared
to other indicators. Our findings indicate that the h-index is better than
other indicators considered (total citation count, citations per paper, and
total paper count) in predicting future scientific achievement. We discuss
reasons for the superiority of the h-index.Comment: Sect. V added on combining h and N_c, with new Fig. 11. Other minor
changes. To be published in PNA
Higher-order Representation and Reasoning for Automated Ontology Evolution
Abstract: The GALILEO system aims at realising automated ontology evolution. This is necessary to enable intelligent agents to manipulate their own knowledge autonomously and thus reason and communicate effectively in open, dynamic digital environments characterised by the heterogeneity of data and of representation languages. Our approach is based on patterns of diagnosis of faults detected across multiple ontologies. Such patterns allow to identify the type of repair required when conflicting ontologies yield erroneous inferences. We assume that each ontology is locally consistent, i.e. inconsistency arises only across ontologies when they are merged together. Local consistency avoids the derivation of uninteresting theorems, so the formula for diagnosis can essentially be seen as an open theorem over the ontologies. The systemâs application domain is physics; we have adopted a modular formalisation of physics, structured by means of locales in Isabelle, to perform modular higher-order reasoning, and visualised by means of development graphs.
T cell cross-reactivity between coxsackievirus and glutamate decarboxylase is associated with a murine diabetes susceptibility allele.
Limited regions of amino acid sequence similarity frequently occur between microbial antigens and host proteins. It has been widely anticipated that during infection such sequence similarities could induce cross-reactive T cell responses, thereby initiating T cell-mediated autoimmune disease. However, the nature of major histocompatibility complex (MHC)-restricted antigen presentation confers a number of constraints that should make this type of T cell cross-reactivity a rare, MHC allele-dependent event. We tested this prediction using two insulin-dependent diabetes mellitus (IDDM)-associated antigens, coxsackievirus P2-C (Cox P2-C) protein and glutamate decarboxylase (GAD65), which share a prototypic sequence similarity of six consecutive amino acids within otherwise unrelated proteins. We surveyed a panel of 10 murine MHC class II alleles that encompass the spectrum of standard alleles for the ability to cross-reactively present Cox P2-C and GAD65. Out of the 10 restriction elements tested, the sequence similarity regions were both dominant determinants and were cross-reactively displayed after the natural processing of whole antigens, only in the context of I-Anod. These data show that cross-reactive T cell recognition of sequence similarity regions in unrelated proteins is confined to certain MHC alleles, which may explain MHC association with autoimmune disease. It is striking that these two diabetes-associated antigens were cross-reactively recognized only in the context of a diabetes susceptibility allele. Since the human and the murine class II alleles associated with IDDM share conserved features, cross-reactive T cell recognition of GAD65 and Cox P2-C may contribute to the pathogenesis of human IDDM and account for the epidemiological association of coxsackievirus with IDDM
Quantum Hydrodynamic Model for the enhanced moments of Inertia of molecules in Helium Nanodroplets: Application to SF
The increase in moment of inertia of SF in helium nanodroplets is
calculated using the quantum hydrodynamic approach. This required an extension
of the numerical solution to the hydrodynamic equation to three explicit
dimensions. Based upon an expansion of the density in terms of the lowest four
Octahedral spherical harmonics, the predicted increase in moment of inertia is
, compared to an experimentally determined value of , i.e., 55% of the observed value. The difference is likely in at
least part due to lack of convergence with respect to the angular expansion,
but at present we do not have access to the full densities from which a higher
order expansion can be determined. The present results contradict those of Kwon
et al., J. Chem. Phys. {\bf 113}, 6469 (2000), who predicted that the
hydrodynamic theory predicted less than 10% of the observed increase in moment
of inertia.Comment: 10 pages, including 1 figur
Two-photon transport through a waveguide coupling to a whispering gallery resonator containing an atom and photon-blockade effect
We investigate the two-photon transport through a waveguide side-coupling to
a whispering-gallery-atom system. Using the Lehmann-Symanzik-Zimmermann (LSZ)
reduction approach, we present the general formula for the two-photon processes
including the two-photon scattering matrices, the wavefunctions and the second
order correlation functions of the out-going photons. Based on the exact
results of the second order correlation functions, we analyze the quantum
statistics behaviors of the out-going photons for two different cases: (a) the
ideal case without the inter-modal coupling in the whispering gallery
resonator; (b) the case in the presence of the inter-modal coupling which leads
to more complex nonlinear behavior. In the ideal case, we show that the system
consists of two independent scattering pathways, a free pathway by a cavity
mode without atomic excitation, and a "Jaynes-Cummings" pathway described by
the Jaynes-Cummings Hamiltonian of a single-mode cavity coupling to an atom.
The free pathway does not contribution to correlated two-photon processes. In
the presence of intermodal mixing, the system no longer exhibit a free resonant
pathway. Instead, both the single-photon and the two photon transport
properties depend on the position of the atom. Thus, in the presence of
intermodal mixing one can in fact tune the photon correlation properties by
changing the position of the atom. Our formalism can be used to treat resonator
and cavity dissipation as well.Comment: 9 pages, 7 figure
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