1,056 research outputs found
Simulations of energetic beam deposition: from picoseconds to seconds
We present a new method for simulating crystal growth by energetic beam
deposition. The method combines a Kinetic Monte-Carlo simulation for the
thermal surface diffusion with a small scale molecular dynamics simulation of
every single deposition event. We have implemented the method using the
effective medium theory as a model potential for the atomic interactions, and
present simulations for Ag/Ag(111) and Pt/Pt(111) for incoming energies up to
35 eV. The method is capable of following the growth of several monolayers at
realistic growth rates of 1 monolayer per second, correctly accounting for both
energy-induced atomic mobility and thermal surface diffusion. We find that the
energy influences island and step densities and can induce layer-by-layer
growth. We find an optimal energy for layer-by-layer growth (25 eV for Ag),
which correlates with where the net impact-induced downward interlayer
transport is at a maximum. A high step density is needed for energy induced
layer-by-layer growth, hence the effect dies away at increased temperatures,
where thermal surface diffusion reduces the step density. As part of the
development of the method, we present molecular dynamics simulations of single
atom-surface collisions on flat parts of the surface and near straight steps,
we identify microscopic mechanisms by which the energy influences the growth,
and we discuss the nature of the energy-induced atomic mobility
Spitzer Observations of the North Ecliptic Pole
We present a photometric catalog for Spitzer Space Telescope warm mission
observations of the North Ecliptic Pole (NEP; centered at , ). The observations are
conducted with IRAC in 3.6 m and 4.5 m bands over an area of 7.04
deg reaching 1 depths of 1.29 Jy and 0.79 Jy in the 3.6
m and 4.5 m bands respectively. The photometric catalog contains
380,858 sources with 3.6 m and 4.5 m band photometry over the
full-depth NEP mosaic. Point source completeness simulations show that the
catalog is 80% complete down to 19.7 AB. The accompanying catalog can be
utilized in constraining the physical properties of extra-galactic objects,
studying the AGN population, measuring the infrared colors of stellar objects,
and studying the extra-galactic infrared background light.Comment: 10 pages, 11 figures and 3 tables. Accepted to the ApJ
Inhomogeneous non-Gaussianity
We propose a method to probe higher-order correlators of the primordial
density field through the inhomogeneity of local non-Gaussian parameters, such
as f_NL, measured within smaller patches of the sky. Correlators between
n-point functions measured in one patch of the sky and k-point functions
measured in another patch depend upon the (n+k)-point functions over the entire
sky. The inhomogeneity of non-Gaussian parameters may be a feasible way to
detect or constrain higher-order correlators in local models of
non-Gaussianity, as well as to distinguish between single and multiple-source
scenarios for generating the primordial density perturbation, and more
generally to probe the details of inflationary physics.Comment: 16 pages, 2 figures; v2: Minor changes and references added. Matches
the published versio
Chromium sequencing: The doors open for genomics of obligate plant pathogens
It is challenging to sequence and assemble genomes of obligate plant pathogens and microorganisms because of limited amounts of DNA, comparatively large genomes and high numbers of repeat regions. We sequenced the 1.2 gigabase genome of an obligate rust fungus, Austropuccinia psidii, the cause of rust on Myrtaceae, with a Chromium 10X library. This technology has mostly been applied for single-cell sequencing in immunological studies of mammals. We compared scaffolds of a genome assembled from the Chromium library with one assembled from combined paired-end and mate-pair libraries, sequenced with Illumina HiSeq. Chromium 10X provided a superior assembly, in terms of number of scaffolds, N50 and number of genes recovered. It required less DNA than other methods and was sequenced and assembled at a lower cost. Chromium sequencing could provide a solution to sequence and assemble genomes of obligate plant pathogens where the amount of available DNA is a limiting factor. © 2018 Future Science. All rights reserved
Trispectrum from Ghost Inflation
Ghost inflation predicts almost scale-invariant primordial cosmological
perturbations with relatively large non-Gaussianity. The bispectrum is known to
have a large contribution at the wavenumbers forming an equilateral triangle
and the corresponding nonlinear parameter is typically of
order . In this paper we calculate trispectrum from ghost inflation
and show that the corresponding nonlinear parameter is typically of
order . We investigate the shape dependence of the trispectrum and see
that it has some features different from DBI inflation. Therefore, our result
may be useful as a template to distinguish ghost inflation from other models of
inflation by future experiments.Comment: 25 pages, 10 figure
Scale-dependence of Non-Gaussianity in the Curvaton Model
We investigate the scale-dependence of f_NL in the self-interacting curvaton
model. We show that the scale-dependence, encoded in the spectral index
n_{f_NL}, can be observable by future cosmic microwave background observations,
such as CMBpol, in a significant part of the parameter space of the model. We
point out that together with information about the trispectrum g_NL, the
self-interacting curvaton model parameters could be completely fixed by
observations. We also discuss the scale-dependence of g_NL and its implications
for the curvaton model, arguing that it could provide a complementary probe in
cases where the theoretical value of n_{f_NL} is below observational
sensitivity.Comment: 14 pages, 5 figures, Eq.(10) correcte
Physiotherapy alone or in combination with corticosteroid injection for acute lateral epicondylitis in general practice: A protocol for a randomised, placebo-controlled study
<p>Abstract</p> <p>Background</p> <p>Lateral epicondylitis is a painful condition responsible for loss of function and sick leave for long periods of time. In many countries, the treatment guidelines recommend a wait-and-see policy, reflecting that no conclusions on the best treatment can be drawn from the available research, published studies and meta-analyses.</p> <p>Methods/Design</p> <p>Randomized double blind controlled clinical trial in a primary care setting. While earlier trials have either compared corticosteroid injections to physical therapy or to naproxen orally, we will compare the clinical effect of physiotherapy alone or physiotherapy combined with corticosteroid injection in the initial treatment of acute tennis elbow. Patients seeing their general practitioner with lateral elbow pain of recent onset will be randomised to one of three interventions: 1: physiotherapy, corticosteroid injection and naproxen or 2: physiotherapy, placebo injection and naproxen or 3: wait and see treatment with naproxen alone. Treatment and assessments are done by two different doctors, and the contents of the injection is unknown to both the treating doctor and patient. The primary outcome measure is the patient's evaluation of improvement after 6, 12, 26 and 52 weeks. Secondary outcome measures are pain, function and severity of main complaint, pain-free grip strength, maximal grip strength, pressure-pain threshold, the patient's satisfaction with the treatment and duration of sick leave.</p> <p>Conclusion</p> <p>This article describes a randomized, double blind, controlled clinical trial with a one year follow up to investigate the effects of adding steroid injections to physiotherapy in acute lateral epicondylitis.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov Identifier: NCT00826462</p
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