17 research outputs found
The water supercooled regime as described by four common water models
The temperature scale of simple water models in general does not coincide
with the natural one. Therefore, in order to make a meaningful evaluation of
different water models a temperature rescaling is necessary. In this paper we
introduce a rescaling using the melting temperature and the temperature
corresponding to the maximum of the heat capacity to evaluate four common water
models (TIP4P-Ew, TIP4P-2005, TIP5P-Ew and Six-Sites) in the supercooled
regime. Although all the models show the same general qualitative behavior, the
TIP5P-Ew appears as the best representation of the supercooled regime when the
rescaled temperature is used. We also analyze, using thermodynamic arguments,
the critical nucleus size for ice growth. Finally, we speculate on the possible
reasons why atomistic models do not usually crystalize while the coarse grained
mW model do crystallize.Comment: 8 pages, 8 figure
An update on the observational facilities at CASLEO
Presentamos una puesta al día sobre los diferentes telescopios e instrumentos disponibles en el Complejo Astronómico El Leoncito (CASLEO), Argentina. Todos los telescopios y sus instrumentos están completamente automatizados, y se operan rutinariamente en modo remoto. Los observadores pueden utilizar el telescopio Jorge Sahade (JS) de 2.15 m para im´agenes, polarimetr´ıa CCD, y espectroscop´ıa (tanto en baja como alta resoluci´on), mientras que se encuentran en estudio nuevos desarrollos instrumentales. Actualmente, cerca del 70 % de los astr´onomos optan por observar en forma remota. El telescopio Helen Sawyer Hogg (HSH) de 0.6 m tambi´en se encuentra disponible para observaci´on remota, y puede usarse para obtener im´agenes con un campo de 9.26×9.26 arcmin2 . Tambi´en operan en el CASLEO dos telescopios menores, a trav´es de sendos convenios con el Nicolaus Copernicus Astronomical Centre (NCAC, Polonia) y el Instituto de Astrof´ısica de Andalucía (IAA, España). La comunidad argentina tiene acceso al 20 % del tiempo disponible en cada uno de estos instrumentos (solo en modo servicio).We present an update on the different telescopes and instruments available at the Complejo Astron´omico El Leoncito (CASLEO), Argentina. All the telescopes and their instruments are fully automated, and are routinely operated in remote mode. Observers can use the 2.15 m Jorge Sahade (JS) telescope for imaging, CCD polarimetry, and spectroscopy (both low and high resolution), future instrumental developments are also in progress. Presently, about 70 % of the astronomers opt to observe remotely. The Helen Sawyer Hogg (HSH) 0.6 m telescope is now also available for remote observing, and it can be used to obtain images with a 9.26 × 9.26 arcmin2 field of view. Two smaller telescopes, operated under agreements with NCAC (Poland) and IAA (Spain), respectively, are also operational at CASLEO. The Argentine community has access to 20 % of the available time at each of these instruments (only in service mode).Fil: Aballay, Jose Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; ArgentinaFil: Cellone, Sergio Aldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; ArgentinaFil: Fernández, G. E. L.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; ArgentinaFil: Giménez, M. A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; ArgentinaFil: Giuliani Ramos, Bruno Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; ArgentinaFil: Giuliani, Jose Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; ArgentinaFil: Godoy, Rodolfo Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; ArgentinaFil: Mammana, Luis Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; ArgentinaFil: Molina, Hector Rolando Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; Argentina. Universidad Nacional de San Juan; ArgentinaFil: Ostrov, Pablo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; ArgentinaFil: Pereyra, Pablo Florencio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; ArgentinaFil: Pinto, Juan Domingo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; Argentin
The Changing Landscape for Stroke\ua0Prevention in AF: Findings From the GLORIA-AF Registry Phase 2
Background GLORIA-AF (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation) is a prospective, global registry program describing antithrombotic treatment patterns in patients with newly diagnosed nonvalvular atrial fibrillation at risk of stroke. Phase 2 began when dabigatran, the first non\u2013vitamin K antagonist oral anticoagulant (NOAC), became available. Objectives This study sought to describe phase 2 baseline data and compare these with the pre-NOAC era collected during phase 1. Methods During phase 2, 15,641 consenting patients were enrolled (November 2011 to December 2014); 15,092 were eligible. This pre-specified cross-sectional analysis describes eligible patients\u2019 baseline characteristics. Atrial fibrillation disease characteristics, medical outcomes, and concomitant diseases and medications were collected. Data were analyzed using descriptive statistics. Results Of the total patients, 45.5% were female; median age was 71 (interquartile range: 64, 78) years. Patients were from Europe (47.1%), North America (22.5%), Asia (20.3%), Latin America (6.0%), and the Middle East/Africa (4.0%). Most had high stroke risk (CHA2DS2-VASc [Congestive heart failure, Hypertension, Age 6575 years, Diabetes mellitus, previous Stroke, Vascular disease, Age 65 to 74 years, Sex category] score 652; 86.1%); 13.9% had moderate risk (CHA2DS2-VASc = 1). Overall, 79.9% received oral anticoagulants, of whom 47.6% received NOAC and 32.3% vitamin K antagonists (VKA); 12.1% received antiplatelet agents; 7.8% received no antithrombotic treatment. For comparison, the proportion of phase 1 patients (of N = 1,063 all eligible) prescribed VKA was 32.8%, acetylsalicylic acid 41.7%, and no therapy 20.2%. In Europe in phase 2, treatment with NOAC was more common than VKA (52.3% and 37.8%, respectively); 6.0% of patients received antiplatelet treatment; and 3.8% received no antithrombotic treatment. In North America, 52.1%, 26.2%, and 14.0% of patients received NOAC, VKA, and antiplatelet drugs, respectively; 7.5% received no antithrombotic treatment. NOAC use was less common in Asia (27.7%), where 27.5% of patients received VKA, 25.0% antiplatelet drugs, and 19.8% no antithrombotic treatment. Conclusions The baseline data from GLORIA-AF phase 2 demonstrate that in newly diagnosed nonvalvular atrial fibrillation patients, NOAC have been highly adopted into practice, becoming more frequently prescribed than VKA in Europe and North America. Worldwide, however, a large proportion of patients remain undertreated, particularly in Asia and North America. (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients With Atrial Fibrillation [GLORIA-AF]; NCT01468701
Systematic Characterization of Gas Phase Binary Pre-Nucleation Complexes Containing H<sub>2</sub>SO<sub>4</sub> + X, [ X = NH<sub>3</sub>, (CH<sub>3</sub>)NH<sub>2</sub>, (CH<sub>3</sub>)<sub>2</sub>NH, (CH<sub>3</sub>)<sub>3</sub>N, H<sub>2</sub>O, (CH<sub>3</sub>)OH, (CH<sub>3</sub>)<sub>2</sub>O, HF, CH<sub>3</sub>F, PH<sub>3</sub>, (CH<sub>3</sub>)PH<sub>2</sub>, (CH<sub>3</sub>)<sub>2</sub>PH, (CH<sub>3</sub>)<sub>3</sub>P, H<sub>2</sub>S, (CH<sub>3</sub>)SH, (CH<sub>3</sub>)<sub>2</sub>S, HCl, (CH<sub>3</sub>)Cl)]. A Computational Study
A systematic
characterization of gas phase binary prenucleation complexes between
H<sub>2</sub>SO<sub>4</sub> (SA) and other molecules present in the
atmosphere (NH<sub>3</sub>, (CH<sub>3</sub>)NH<sub>2</sub>, (CH<sub>3</sub>)<sub>2</sub>NH, (CH<sub>3</sub>)<sub>3</sub>N, H<sub>2</sub>O, (CH<sub>3</sub>)OH, (CH<sub>3</sub>)<sub>2</sub>O, HF, CH<sub>3</sub> F, PH<sub>3</sub>, (CH<sub>3</sub>)PH<sub>2</sub>, (CH<sub>3</sub>)<sub>2</sub>PH, (CH<sub>3</sub>)<sub>3</sub>P, H<sub>2</sub>S, (CH<sub>3</sub>)SH, (CH<sub>3</sub>)<sub>2</sub>S, HCl, (CH<sub>3</sub>)Cl) has been carried out using the ωB97X-D/6-311++(2d,2p)
method at the DFT level of theory. A relationship between the energy
gap of the SA’s LUMO and the partner molecule’s HOMO,
and the increasing number of methyl groups −CH<sub>3</sub> in
the SA’s partner molecule is provided. The binding energies
of the bimolecular complexes are found to be related to the electron
density in the hydrogen bond critical point, the HOMO–LUMO
energy gap, the nature of the hydrogen acceptor atom, and the frequencies
shift of acid OH bonds. The results show how the frontier orbital
compatibility determines the binding energy and that the properties
of SA’s OH bond which remains free of interactions are affected
by the bimolecular adduct formation
Frontier molecular orbital analysis for determining the equilibrium geometries of atmospheric prenucleation complexes
A systematic characterization of the frontier molecular orbitals (FMO) of gas-phase prenucleation complexes between H2SO4 and other molecules present in the atmosphere (NH3, H2O, (CH3)OH, HF, (CH3)2PH, (CH3)SH) is carried out using the ωB97X-D/6-311++(2d,2p) method at the density functional theory level of theory. The FMO theory principles are taken into account to gain insight into the nature of intermolecular interactions. The results show that the highest occupied molecular orbital/lowest unoccupied molecular orbital molecular system characterization can be adopted as a complementary tool of analysis in supporting the study of atmospheric prenucleation processes. It is shown that the stability and the spatial arrangement of molecular systems can be also thought in terms of inter- and intra-molecular energy gaps ΔEHL that play an important role in the development of association processes.Fil: Sebastianelli, Paolo. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina. Universidad Nacional de La Pampa; ArgentinaFil: Pereyra, Rodolfo Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentin