5,613 research outputs found
Statin-associated muscle symptoms (SAMS) in primary prevention for cardiovascular disease in older adults:A protocol for a systematic review and meta-analysis of randomised controlled trials
IntroductionAlthough statins are commonly used for prevention of cardiovascular disease, there is limited evidence about statin-related adverse effects in older people. Statin-related adverse events (AEs), especially the statin-associated muscle symptoms (SAMS), are the most common reasons for their discontinuation. Therefore, it is important to determine the risk of SAMS in the older population. We will undertake a systematic review and meta-analysis primarily focusing on the risk of SAMS and secondarily targeting myopathy, rhabdomyolysis, AEs and serious AEs, dropouts due to SAMS in run-in period, related permanent discontinuation rate of statins and creatine kinase level, among older people who received statins for primary prevention.Methods and analysisThis study has been developed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols statement. We will include randomised controlled trials in which statin was compared with placebo with at least 1āyear follow-up among older adults aged ā„65. This review is an update of a Cochrane systematic review that included the articles published before 2012. Cochrane Central Register of Controlled Trials, Medline OvidSP and Embase electronic database searches will be performed to identify relevant articles, limiting the publication date from 1 January 2012 to 13 February 2017. There will be no language limitation. Two independent reviewers will screen titles and abstracts and full text in duplicate. Risk of bias and evidence quality will be assessed using the Cochrane Collaborationās tool and the Grading of Recommendations Assessment, Development and Evaluation approach, respectively. A meta-analysis using pooled data will be undertaken, if appropriate. We will also perform metaregression and subgroup analyses to identify sources of heterogeneity.Ethics and disseminationThis study is exempt from ethics approval due to the anonymous and aggregated data used. The outcomes will be disseminated by conference presentations and published in a peer-reviewed journal.Trial registration numberCRD42017058436.</jats:sec
Price Level Convergence Among United States Cities: Lessons for the European Central Bank
We study the dynamics of price indices for major U.S. cities using panel econometric methods and find that relative price levels among cities mean revert at an exceptionally slow rate. In a panel of 19 cities from 1918 to 1995, we estimate the half-life of convergence to be approximately nine years. These estimates provide an upper bound on speed of convergence that participants in European Monetary Union are likely to experience. The surprisingly slow rate of convergence can be explained by a combination of the presence of transportation costs, differential speeds of adjustment to small and large shocks, and the inclusion of non-traded good prices in the overall price index.
Archaeological Survey Investigations of Private Land within the boundaries of the proposed Lower Bois dāArc Creek Reservoir Project, Fannin County, Texas
At the request of a private landowner that has property within the boundaries of the proposed Lower Bois dāArc Creek Reservoir in Fannin County, we completed volunteer archaeological survey investigations on a portion of this tract of private land on July 18, 2015. The proposed Lower Bois dāArc Creek Reservoir is to be more than 16,500 acres in size; the project sponsor is the North Texas Municipal Water District, and the Tulsa District of the U.S. Army Corps of Engineers is currently reviewing the project sponsorās application for a Department of the Army permit under Section 404 of the Clean Water Act to construct the reservoir and associated facilities.
Although the project area associated with the proposed reservoir is more than 17,000 acres, only 5,000 acres of the proposed project have received an archaeological survey. Based on consultation between the project sponsor, the Texas Historical Commission, and the Tulsa District, the remainder of the project area will apparently not receive archaeological survey investigations. The private lands we have investigated along Bois dāArc Creek in the proposed reservoir area have not been examined previously by a professional archaeological survey team; these lands will be inundated by the flood pool of the reservoir as currently proposed. The landowner had contacted the Tulsa District in 2008 to inform them that there were archaeological sites on the property, but the Tulsa District has yet to follow up on that information
Charging of ice-vapor interfaces
International audienceThe time resolved chemical composition of aerosol particles, formed by the oxidation of alpha-pinene has been investigated by liquid chromatography/mass spectrometry (LC-MS) using negative and positive ionisation methods (ESI(-) and APCI(+)). The experiments were performed at the EUPHORE facility in Valencia (Spain) under various experimental conditions, including dark ozone reactions, photosmog experiments with low NOx mixing ratios and reaction with OH radicals in the absence of NOx (H2O2-photolysis). Particles were sampled on PTFE filters at different stages of the reaction and extracted with methanol. The predominant products from alpha-pinene in the particulate phase are cis-pinic acid, cis-pinonic acid and hydroxy-pinonic acid isomers. Another major compound with molecular weight 172 was detected, possibly a hydroxy-carboxylic acid. These major compounds account for 50% to 80% of the identified aerosol products, depending on the time of sampling and type of experiment. In addition, more than 20 different products have been detected and structures have been tentatively assigned based on their molecular weight and responses to the different ionisation modes. The different experiments performed showed that the aerosol formation is mainly caused by the ozonolysis reaction. The highest aerosol yields were observed in the dark ozone experiments, for which also the highest ratios of mass of identified products to the formed aerosol mass were found (30% to 50%, assuming a density of 1 g cm-3)
Thermodynamics and the Global Optimization of Lennard-Jones clusters
Theoretical design of global optimization algorithms can profitably utilize
recent statistical mechanical treatments of potential energy surfaces (PES's).
Here we analyze the basin-hopping algorithm to explain its success in locating
the global minima of Lennard-Jones (LJ) clusters, even those such as \LJ{38}
for which the PES has a multiple-funnel topography, where trapping in local
minima with different morphologies is expected. We find that a key factor in
overcoming trapping is the transformation applied to the PES which broadens the
thermodynamic transitions. The global minimum then has a significant
probability of occupation at temperatures where the free energy barriers
between funnels are surmountable.Comment: 13 pages, 13 figures, revte
The double-funnel energy landscape of the 38-atom Lennard-Jones cluster
The 38-atom Lennard-Jones cluster has a paradigmatic double-funnel energy
landscape. One funnel ends in the global minimum, a face-centred-cubic (fcc)
truncated octahedron. At the bottom of the other funnel is the second lowest
energy minimum which is an incomplete Mackay icosahedron. We characterize the
energy landscape in two ways. Firstly, from a large sample of minima and
transition states we construct a disconnectivity tree showing which minima are
connected below certain energy thresholds. Secondly we compute the free energy
as a function of a bond-order parameter. The free energy profile has two
minima, one which corresponds to the fcc funnel and the other which at low
temperature corresponds to the icosahedral funnel and at higher temperatures to
the liquid-like state. These two approaches show that the greater width of the
icosahedral funnel, and the greater structural similarity between the
icosahedral structures and those associated with the liquid-like state, are the
cause of the smaller free energy barrier for entering the icosahedral funnel
from the liquid-like state and therefore of the cluster's preferential entry
into this funnel on relaxation down the energy landscape. Furthermore, the
large free energy barrier between the fcc and icosahedral funnels, which is
energetic in origin, causes the cluster to be trapped in one of the funnels at
low temperature. These results explain in detail the link between the
double-funnel energy landscape and the difficulty of global optimization for
this cluster.Comment: 12 pages, 11 figures, revte
UNDERSTANDING TECHNOLOGY ADOPTION THROUGH SYSTEM DYNAMICS MODELING: IMPLICATIONS FOR AGRIBUSINESS MANAGEMENT
This work demonstrates the utility of sophisticated simulation tools in aiding agribusiness managers' decision making. The system dynamics model developed here provides insight into the use of such models to evaluate potential adoption rates and diffusion patterns of yield mapping and monitoring technologies. The model allows for comparative analyses of the possible effects of different profit assumptions on adoption and diffusion.Agribusiness, Research and Development/Tech Change/Emerging Technologies,
Magnetic Wreaths and Cycles in Convective Dynamos
Solar-type stars exhibit a rich variety of magnetic activity. Seeking to
explore the convective origins of this activity, we have carried out a series
of global 3D magnetohydrodynamic (MHD) simulations with the anelastic spherical
harmonic (ASH) code. Here we report on the dynamo mechanisms achieved as the
effects of artificial diffusion are systematically decreased. The simulations
are carried out at a nominal rotation rate of three times the solar value
(3), but similar dynamics may also apply to the Sun. Our previous
simulations demonstrated that convective dynamos can build persistent toroidal
flux structures (magnetic wreaths) in the midst of a turbulent convection zone
and that high rotation rates promote the cyclic reversal of these wreaths. Here
we demonstrate that magnetic cycles can also be achieved by reducing the
diffusion, thus increasing the Reynolds and magnetic Reynolds numbers. In these
more turbulent models, diffusive processes no longer play a significant role in
the key dynamical balances that establish and maintain the differential
rotation and magnetic wreaths. Magnetic reversals are attributed to an
imbalance in the poloidal magnetic induction by convective motions that is
stabilized at higher diffusion levels. Additionally, the enhanced levels of
turbulence lead to greater intermittency in the toroidal magnetic wreaths,
promoting the generation of buoyant magnetic loops that rise from the deep
interior to the upper regions of our simulated domain. The implications of such
turbulence-induced magnetic buoyancy for solar and stellar flux emergence are
also discussed.Comment: 21 pages, 16 figures, accepted for publication in Ap
Revealing the galaxy-halo connection in IllustrisTNG
We use the IllustrisTNG (TNG) simulations to explore the galaxy-halo
connection as inferred from state-of-the-art cosmological,
magnetohydrodynamical simulations. With the high mass resolution and large
volume achieved by combining the 100 Mpc (TNG100) and 300 Mpc (TNG300) volumes,
we establish the mean occupancy of central and satellite galaxies and their
dependence on the properties of the dark matter haloes hosting them. We derive
best-fitting HOD parameters from TNG100 and TNG300 for target galaxy number
densities of Mpc and Mpc, respectively, corresponding to a minimum galaxy stellar
mass of and
, respectively, in hosts more massive
than . Consistent with previous work, we find that
haloes located in dense environments, with low concentrations, later formation
times, and high angular momenta are richest in their satellite population. At
low mass, highly-concentrated haloes and those located in overdense regions are
more likely to contain a central galaxy. The degree of environmental dependence
is sensitive to the definition adopted for the physical boundary of the host
halo. We examine the extent to which correlations between galaxy occupancy and
halo properties are independent and demonstrate that HODs predicted by halo
mass and present-day concentration capture the qualitative dependence on the
remaining halo properties. At fixed halo mass, concentration is a strong
predictor of the stellar mass of the central galaxy, which may play a defining
role in the fate of the satellite population. The radial distribution of
satellite galaxies, which exhibits a universal form across a wide range of host
halo mass, is described accurately by the best-fit NFW density profile of their
host haloes.Comment: 20 pages, 13 figures, 1 table, comments welcom
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