1,074 research outputs found

    Effectiveness and Content Analysis of Interventions to Enhance Oral Antidiabetic Drug Adherence in Adults with Type 2 Diabetes : Systematic Review and Meta-Analysis

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    We thank Frederic Bergeron, information scientist, for assistance in search strategies. We thank American Journal Experts for editing the text. Source of financial support: This study was funded by the Laval University Chair on Adherence to Treatments. This Chair is supported by nonrestricted grants from AstraZeneca Canada, Merck Canada, Sanofi Canada, and Pfizer Canada and from the Prends soin de toi program (a Quebec provincial program for the improvement of public health).Peer reviewedPostprin

    Evaporation and clustering of ammonia droplets in a hot environment

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    Recent developments in the transition to zero-carbon fuels show that ammonia is a valid candidate for combustion. However, liquid ammonia combustion is difficult to stabilize due to a large latent heat of evaporation, which generates a strong cooling effect that adversely affects the flame stabilization and combustion efficiency. In addition, the slow burning rate of ammonia enhances the undesired production of NOx and N2O. To increase the flame speed, ammonia must be blended with a gaseous fuel having a high burning rate. In this context, a deeper understanding of the droplet dynamics is required to optimize the combustor design. To provide reliable physical insights into diluted ammonia sprays blended with gaseous methane, direct numerical simulations are employed. Three numerical experiments were performed with cold, standard, and hot ambient in nonreactive conditions. The droplet radius and velocity distribution, as well as the mass and heat coupling source terms are compared to study the effects on the evaporation. Since the cooling effect is stronger than the heat convection between the droplet and the environment in each case, ammonia droplets do not experience boiling. On the other hand, the entrainment of dry air into the ammonia-methane mixture moves the saturation level beyond 100% and droplets condense. The aforementioned phenomena are found to strongly affect the droplet evolution. Finally, a three-dimensional Voronoi analysis is performed to characterize the dispersive or clustering behavior of droplets by means of the definition of a clustering index

    Analysis of meteorology-chemistry interactions during air pollution episodes using online coupled models within AQMEII Phase-2

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    This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).This study reviews the top ranked meteorology and chemistry interactions in online coupled models recommended by an experts’ survey conducted in COST Action EuMetChem and examines the sensitivity of those interactions during two pollution episodes: the Russian forest fires 25 Jul -15 Aug 2010 and a Saharan dust transport event from 1 Oct -31 Oct 2010 as a part of the AQMEII phase-2 exercise. Three WRF-Chem model simulations were performed for the forest fire case for a baseline without any aerosol feedback on meteorology, a simulation with aerosol direct effects only and a simulation including both direct and indirect effects. For the dust case study, eight WRF-Chem and one WRF-CMAQ simulations were selected from the set of simulations conducted in the framework of AQMEII. Of these two simulations considered no feedbacks, two included direct effects only and five simulations included both direct and indirect effects. The results from both episodes demonstrate that it is important to include the meteorology and chemistry interactions in online-coupled models. Model evaluations using routine observations collected in AQMEII phase-2 and observations from a station in Moscow show that for the fire case the simulation including only aerosol direct effects has better performance than the simulations with no aerosol feedbacks or including both direct and indirect effects. The normalized mean biases are significantly reduced by 10-20% for PM10 when including aerosol direct effects. The analysis for the dust case confirms that models perform better when including aerosol direct effects, but worse when including both aerosol direct and indirect effects, which suggests that the representation of aerosol indirect effects needs to be improved in the model.Peer reviewedFinal Published versio

    Heavy quark flavour dependence of multiparticle production in QCD jets

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    After inserting the heavy quark mass dependence into QCD partonic evolution equations, we determine the mean charged hadron multiplicity and second multiplicity correlators of jets produced in high energy collisions. We thereby extend the so-called dead cone effect to the phenomenology of multiparticle production in QCD jets and find that the average multiplicity of heavy-quark initiated jets decreases significantly as compared to the massless case, even taking into account the weak decay products of the leading primary quark. We emphasize the relevance of our study as a complementary check of bb-tagging techniques at hadron colliders like the Tevatron and the LHC.Comment: Version revised, accepted for publication in JHEP, 21 pages and 7 figure

    Study of CO2 desublimation during cryogenic carbon capture using the lattice Boltzmann method

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    Cryogenic carbon capture (CCC) can preferentially desublimate CO2 out of the flue gas. A widespread application of CCC requires a comprehensive understanding of CO2 desublimation properties. This is, however, highly challenging due to the multiphysics behind it. This study proposes a lattice Boltzmann (LB) model to study CO2 desublimation on a cooled cylinder surface during CCC. In two-dimensional (2-D) simulations, various CO2 desublimation and capture behaviours are produced in response to different operation conditions, namely, gas velocity (Péclet number Pe) and cylinder temperature (subcooling degree Tsub). As Pe increases or Tsub decreases, the desublimation rate gradually becomes insufficient compared with the CO2 supply via convection/diffusion. Correspondingly, the desublimated solid CO2 layer (SCL) transforms from a loose (i.e. cluster-like, dendritic or incomplete) structure to a dense one. Four desublimation regimes are thus classified as diffusion-controlled, joint-controlled, convection-controlled and desublimation-controlled regimes. The joint-controlled regime shows quantitatively a desirable CO2 capture performance: fast desublimation rate, high capture capacity, and full cylinder utilization. Regime distributions are summarized on a Pe–Tsub space to determine operation parameters for the joint-controlled regime. Moreover, three-dimensional simulations demonstrate four similar desublimation regimes, verifying the reliability of 2-D results. Under regimes with loose SCLs, however, the desublimation process shows an improved CO2 capture performance in three dimensions. This is attributed to the enhanced availability of gas–solid interface and flow paths. This work develops a reliable LB model to study CO2 desublimation, which can facilitate applications of CCC for mitigating climate change

    Scaling of the coercivity with the geometrical parameters in epitaxial Fe antidot arrays

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    We studied a series of square lattice antidot arrays, with diameter and lattice parameter from hundreds of nanometers to some microns, fabricated using two lithography techniques in epitaxial Fe(001) films. The coercivity increase of each array with respect to its base film can be scaled to a simple geometric parameter, irrespective of the lithography technique employed. Magnetic transmission x-ray microscopy studies, in arrays fabricated on polycrystalline Fe films deposited on silicon nitride membranes, evidenced the propagation of reversed domains from the edges of the arrays, in agreement with the coercivity analysis of the epitaxial arrays and with micromagnetic models

    Mass-dependent evolution of the relation between supermassive black hole mass and host spheroid mass since z ~ 1

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    We investigate the evolution of supermassive black hole mass (M_BH) and the host spheroid mass (M_sph) in order to track the history of the M_BH-M_sph relationship. The typical mass increase of M_BH is calculated by a continuity equation and accretion history, which is estimated from the active galactic nucleus (AGN) luminosity function. The increase in M_sph is also calculated by using a continuity equation and a star formation model, which uses observational data for the formation rate and stellar mass function. We find that the black hole to spheroid mass ratio is expected to be substantially unchanged since z~1.2 for high mass objects (M_BH>10^8.5M_SUN and M_sph>10^11.3M_SUN). In the same redshift range, the spheroid mass is found to increase more rapidly than the black hole mass if M_sph>10^11M_SUN. The proposed mass-dependent model is consistent with the current available observational data in the M_BH-M_sph diagram.Comment: 15 pages, 8 figures, accepted to MNRA

    Chronology of mineralization of the permanent mandibular second molar teeth and forensic age estimation

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    Forensic age estimation frequently relies upon the chronology of mineralization of the third molar teeth. However, even when present, third molar teeth cannot always be used for estimating age in people who are classified as minors. Seconds molars develop earlier and in a more predictable way, and therefore are often more reliable for age estimation in this age group. This study aims to contribute to forensic age estimation using an age threshold of 14-years, studying the stages of development of permanent mandibular second molar teeth mineralization. 367 orthopantograms of a Portuguese population group, aged between 3 and 19 years, were studied. The stages of mineralization of mandibular permanent second molar teeth were studied following the classification stages proposed by Demirjian et al. Stage descriptive analysis was performed, and associations between age and stage were studied.A logistic regression to determine age over 14 years, using maturation stages and sex as a predictive variables, was made. A second sample was used for testing the model. The significance level was set at 5%. The model correctly classified 92.0% of cases overall. The equation was tested in the second sample, and the results showed that there were no statistical significant differences between the binary real age (i.e. age < 14 and age ≥ 14 years) and the estimated age (p = 0.109). The developed model is useful for age estimation using 14-years as a threshold. However, stage maturation analyses showed that stage F, in males, and stages G and H, in both sexes, lead to an estimated age with significant statistical differences from chronological age
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