211 research outputs found
Large well-relaxed models of vitreous silica, coordination numbers and entropy
A Monte Carlo method is presented for the simulation of vitreous silica.
Well-relaxed networks of vitreous silica are generated containing up to 300,000
atoms. The resulting networks, quenched under the BKS potential, display
smaller bond-angle variations and lower defect concentrations, as compared to
networks generated with molecular dynamics. The total correlation functions
T(r) of our networks are in excellent agreement with neutron scattering data,
provided that thermal effects and the maximum inverse wavelength used in the
experiment are included in the comparison. A procedure commonly used in
experiments to obtain coordination numbers from scattering data is to fit peaks
in rT(r) with a gaussian. We show that this procedure can easily produce
incorrect results. Finally, we estimate the configurational entropy of vitreous
silica.Comment: 7 pages, 4 figures (two column version to save paper
Tisa: A Language Design and Modular Verification Technique for Temporal Policies in Web Services
Web services are distributed software components, that are decoupled from each other using interfaces with specified functional behaviors. However, such behavioral specifications are insufficient to demonstrate compliance with certain temporal non-functional policies. An example is demonstrating that a patientâs health-related query sent to a health care service is answered only by a doctor (and not by a secretary). Demonstrating compliance with such policies is important for satisfying governmental privacy regulations. It is often necessary to expose the internals of the web service implementation for demonstrating such compliance, which may compromise modularity. In this work, we provide a language design that enables such demonstrations, while hiding majority of the serviceâs source code. The key idea is to use greybox specifications to allow service providers to selectively hide and expose parts of their implementation. The overall problem of showing compliance is then reduced to two subproblems: whether the desired properties are satisfied by the serviceâs greybox specification, and whether this greybox specification is satisfied by the serviceâs implementation. We specify policies using LTL and solve the first problem by model checking. We solve the second problem by refinement techniques
Quantitative PCR tissue expression profiling of the human SGLT2 gene and related family members
SGLT2 (for âSodium GLucose coTransporterâ protein 2) is the major protein responsible for glucose reabsorption in the kidney and its inhibition has been the focus of drug discovery efforts to treat type 2 diabetes. In order to better clarify the human tissue distribution of expression of SGLT2 and related members of this cotransporter class, we performed TaqManâą (Applied Biosystems, Foster City, CA, USA) quantitative polymerase chain reaction (PCR) analysis of SGLT2 and other sodium/glucose transporter genes on RNAs from 72 normal tissues from three different individuals. We consistently observe that SGLT2 is highly kidney specific while SGLT5 is highly kidney abundant; SGLT1, sodium-dependent amino acid transporter (SAAT1), and SGLT4 are highly abundant in small intestine and skeletal muscle; SGLT6 is expressed in the central nervous system; and sodium myoinositol cotransporter is ubiquitously expressed across all human tissues
Attentive Learning of Sequential Handwriting Movements: A Neural Network Model
Defense Advanced research Projects Agency and the Office of Naval Research (N00014-95-1-0409, N00014-92-J-1309); National Science Foundation (IRI-97-20333); National Institutes of Health (I-R29-DC02952-01)
Does technology and Innovation Management improve Market Position? Empirical Evidence from Innovating Firms in South Africa
There is a growing recognition of the central role of technology and knowledge management for market success of organizations. Little is empirically know, however, about this relationship. Drawing on the South African Innovation Survey, a unique dataset on innovative behavior of South African firms in manufacturing and services, this paper investigates the question to what extent and in which ways do technology and innovation management activities affect firmsâ market position. Findings show that conducting technology strategy activities pays out. Moreover, especially a combination of internal and external technology audits seems to be beneficial for organizational performance
The Rise and Fall, and the Rise (Again) of Feminist Research in Music: 'What Goes Around Comes Around'
This article reports from a two-phase study that involved an analysis of the extant literature followed by a three-part survey answered by seventy-one women composers. Through these theoretical and empirical data, the authors explore the relationship between gender and musicâs symbolic and cultural capital. Bourdieuâs theory of the habitus is employed to understand the gendered experiences of the female composers who participated in the survey. The article suggests that these female composers have different investments in gender but that, overall, they reinforce the male habitus given that the female habitus occupies a subordinate position in relation to that of the male. The findings of the study also suggest a connection between contemporary feminism and the attitudes towards gender held by the participants. The article concludes that female composers classify themselves, and others, according to gendered norms and that these perpetuate the social order in music in which the male norm dominates
Prospects for e+e- physics at Frascati between the phi and the psi
We present a detailed study, done in the framework of the INFN 2006 Roadmap,
of the prospects for e+e- physics at the Frascati National Laboratories. The
physics case for an e+e- collider running at high luminosity at the phi
resonance energy and also reaching a maximum center of mass energy of 2.5 GeV
is discussed, together with the specific aspects of a very high luminosity
tau-charm factory. Subjects connected to Kaon decay physics are not discussed
here, being part of another INFN Roadmap working group. The significance of the
project and the impact on INFN are also discussed. All the documentation
related to the activities of the working group can be found in
http://www.roma1.infn.it/people/bini/roadmap.html.Comment: INFN Roadmap Report: 86 pages, 25 figures, 9 table
TRY plant trait database â enhanced coverage and open access
Plant traitsâthe morphological, anatomical, physiological, biochemical and phenological characteristics of plantsâdetermine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of traitâbased plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traitsâalmost complete coverage for âplant growth formâ. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and traitâenvironmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives
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