The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
Gregory A Voth - One of the best experts on this subject based on the ideXlab platform.
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ab initio molecular dynamics simulation of aqueous proton solvation and transport revisited
Journal of Chemical Physics, 2005Co-Authors: Sergei Izvekov, Gregory A VothAbstract:The solvation and transport of the hydrated excess proton is studied using the Car-Parrinello molecular-dynamics (CPMD) simulation method. The simulations were performed using BLYP and HCTH gradient-corrected exchange-correlation energy functionals. The fictitious Electronic Mass was chosen to be small enough so that the underlying water structural and dynamical properties were converged with respect to this important CPMD simulation parameter. An unphysical overstructuring of liquid water in the CPMD simulations using the BLYP functional resulted in the formation of long-lived hydrogen-bonding structures involving the excess proton and a particular (special) water oxygen. The excess proton was observed to be attracted to the special oxygen through the entire length of the BLYP CPMD simulations. Consequently, the excess proton diffusion was limited by the mobility of the special oxygen in the slowly diffusing water network and, in turn, the excess proton self-diffusion coefficient was found to be signific...
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ab initio molecular dynamics propagating the density matrix with gaussian orbitals iii comparison with born oppenheimer dynamics
Journal of Chemical Physics, 2002Co-Authors: Bernhard H Schlegel, Srinivasan S Iyengar, Xiaosong Li, John M Millam, Gregory A Voth, Gustavo E Scuseria, Michael J FrischAbstract:In a recently developed approach to ab initio molecular dynamics (ADMP), we used an extended Lagrangian to propagate the density matrix in a basis of atom centered Gaussian functions. Results of trajectory calculations obtained by this method are compared with the Born–Oppenheimer approach (BO), in which the density is converged at each step rather than propagated. For NaCl, the vibrational frequency with ADMP is found to be independent of the fictitious Electronic Mass and to be equal to the BO trajectory result. For the photodissociation of formaldehyde, H2CO→H2+CO, and the three body dissociation of glyoxal, C2H2O2→H2+2CO, very good agreement is found between the Born–Oppenheimer trajectories and the extended Lagrangian approach in terms of the rotational and vibrational energy distributions of the products. A 1.2 ps simulation of the dynamics of chloride ion in a cluster of 25 water molecules was used as a third test case. The Fourier transform of the velocity–velocity autocorrelation function showed ...
Gabor D Kelen - One of the best experts on this subject based on the ideXlab platform.
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Electronic Mass casualty assessment and planning scenarios emcaps development and application of computer modeling to selected national planning scenarios for high consequence events
Annals of Emergency Medicine, 2009Co-Authors: James J Scheulen, Meridith H Thanner, Christian K Latimer, Jeffrey Brown, Gabor D KelenAbstract:Few tools exist that are sufficiently robust to allow manipulation of key input variables to produce casualty estimates resulting from high-consequence events reflecting local or specific regions of concern. This article describes the design and utility of a computerized modeling simulation tool, Electronic Mass Casualty Assessment and Planning Scenarios (EMCAPS), developed to have broad application across emergency management and public health fields as part of a catastrophic events preparedness planning process. As a scalable, flexible tool, EMCAPS is intended to support emergency preparedness planning efforts at multiple levels ranging from local health systems to regional and state public health departments to Metropolitan Medical Response System jurisdictions. Designed around the subset of the National Planning Scenarios with health effects, advanced by the US Department of Homeland Security, the tool's platform is supported by the detailed descriptions and readily retrievable evidence-based assumptions of each scenario. The EMCAPS program allows the user to manipulate key scenario-based input variables that would best reflect the region or locale of interest. Inputs include population density, vulnerabilities, event size, and potency, as applicable. Using these inputs, EMCAPS generates the anticipated population-based health surge influence of the hazard scenario. Casualty estimates are stratified by injury severity/types where appropriate. Outputs are graph and table tabulations of surge estimates. The data can then be used to assess and tailor response capabilities for specific jurisdictions, organizations, and health care systems. EMCAPS may be downloaded without cost from http://www.hopkins-cepar.org/EMCAPS/EMCAPS.html as shareware.
Giulia Galli - One of the best experts on this subject based on the ideXlab platform.
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towards an assessment of the accuracy of density functional theory for first principles simulations of water ii
Journal of Chemical Physics, 2004Co-Authors: Eric Schwegler, Jeffrey C Grossman, Francois Gygi, Giulia GalliAbstract:A series of Car–Parrinello (CP) molecular dynamics simulations of water are presented, aimed at assessing the accuracy of density functional theory in describing the structural and dynamical properties of water at ambient conditions. We found negligible differences in structural properties obtained using the Perdew–Burke–Ernzerhof or the Becke–Lee–Yang–Parr exchange and correlation energy functionals; we also found that size effects, although not fully negligible when using 32 molecule cells, are rather small. In addition, we identified a wide range of values of the fictitious Electronic Mass (μ) entering the CP Lagrangian for which the Electronic ground state is accurately described, yielding trajectories and average properties that are independent of the value chosen. However, care must be exercised not to carry out simulations outside this range, where structural properties may artificially depend on μ. In the case of an accurate description of the Electronic ground state, and in the absence of proton ...
Sergei Izvekov - One of the best experts on this subject based on the ideXlab platform.
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ab initio molecular dynamics simulation of aqueous proton solvation and transport revisited
Journal of Chemical Physics, 2005Co-Authors: Sergei Izvekov, Gregory A VothAbstract:The solvation and transport of the hydrated excess proton is studied using the Car-Parrinello molecular-dynamics (CPMD) simulation method. The simulations were performed using BLYP and HCTH gradient-corrected exchange-correlation energy functionals. The fictitious Electronic Mass was chosen to be small enough so that the underlying water structural and dynamical properties were converged with respect to this important CPMD simulation parameter. An unphysical overstructuring of liquid water in the CPMD simulations using the BLYP functional resulted in the formation of long-lived hydrogen-bonding structures involving the excess proton and a particular (special) water oxygen. The excess proton was observed to be attracted to the special oxygen through the entire length of the BLYP CPMD simulations. Consequently, the excess proton diffusion was limited by the mobility of the special oxygen in the slowly diffusing water network and, in turn, the excess proton self-diffusion coefficient was found to be signific...
Ieva Andersone - One of the best experts on this subject based on the ideXlab platform.
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Latvia: : Amendments adopted to the Electronic Mass Media Law
2020Co-Authors: Ieva AndersoneAbstract:On 19 January 2016, new amendments to the Latvian Electronic Mass Media Law (EMML) came into force. The amendments have been adopted by Saeima (the Latvian Parliament) on 17 December 2015. The amendments are substantial, as they introduce new concepts in the EMML, supplement the list of must-carry provisions, and supplement the conditions on which the Latvian regulatory authorities may suspend broadcasts and on-demand services from other countries, including European Union countries.
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The National Electronic Mass Media Council explores legaloptions to limit certain retransmissions
2020Co-Authors: Ieva AndersoneAbstract:The Nacionala elektronisko pla�sazinas lidzeklu padome (National Electronic Mass Media Council), the national regulatory authority, has been recently exploring legal options for limiting retransmission of certain television broadcasts, which might be contrary to Latvian and EU law. Within the context of the Ukraine and Crimea crisis, the Council has received numerous complaints that several Russian language television channels contain broadcasts, which allegedly promote war and military conflict, as well as include incitement to hatred and destruction of the territorial unity of countries. Also, the Public Consultative Council, a consulting body to the Council, is of the opinion that several channels intentionally broadcast misleading information unfavourable to Latvian territorial integrity.
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Latvia: : Amendments to Electronic Media Law adopted
2020Co-Authors: Ieva AndersoneAbstract:On 24 April 2014, the Saeima (the Latvian Parliament) has adopted amendments to the Electronic Media Law. The amendments clarify the criteria for the status of national Electronic Mass media, modify the conditions on which a broadcasting permit may be revoked, extend the period for storing the records of broadcasts and provide for other minor changes.
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Latvia: Regulator suspends the retransmission of a Russian TV channel
2020Co-Authors: Ieva AndersoneAbstract:On 7 April 2016, the Nacionālā elektronisko plassaziņas līdzekļu padome (National Electronic Mass Media Council), the national regulatory authority (the Council) adopted a decision to suspend the retransmission of the TV channel Rossija RTR for a period of 6 months. The suspension duty applies to all retransmission operators; to cable and satellite operators, as well as to Internet television providers.