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

Ubicación y peso de Micelio de Sclerotinia sclerotiorum para producir infeccion en lechuga (Lactuca sativa)

p.85-88El objetivo del presente trabajo es evaluar la distancia crítica para la inoculación del micelio de Sclerotinia sclerotiorum al cuello de la planta de lechuga (Lactuca sativa) y el peso del mismo para producir infección y caída de las plántulas en cámara de cultivo. La mayor cantidad de plantas caídas se obtuvo con 0,7 y 2,8 grs de inoculo (masa miceliar) ubicado junto al cuello de la planta. Estos resultados pueden ser de utilidad para estudios acerca del control cultural, químico o biológico de la podredumbre ocasionada por S. sclerotiorum en lechuga

Local stochastic non-Gaussianity and N-body simulations

Large-scale clustering of highly biased tracers of large-scale structure has emerged as one of the best observational probes of primordial non-Gaussianity of the local type (i.e. f_{NL}^{local}). This type of non-Gaussianity can be generated in multifield models of inflation such as the curvaton model. Recently, Tseliakhovich, Hirata, and Slosar showed that the clustering statistics depend qualitatively on the ratio of inflaton to curvaton power \xi after reheating, a free parameter of the model. If \xi is significantly different from zero, so that the inflaton makes a non-negligible contribution to the primordial adiabatic curvature, then the peak-background split ansatz predicts that the halo bias will be stochastic on large scales. In this paper, we test this prediction in N-body simulations. We find that large-scale stochasticity is generated, in qualitative agreement with the prediction, but that the level of stochasticity is overpredicted by ~30%. Other predictions, such as \xi independence of the halo bias, are confirmed by the simulations. Surprisingly, even in the Gaussian case we do not find that halo model predictions for stochasticity agree consistently with simulations, suggesting that semi-analytic modeling of stochasticity is generally more difficult than modeling halo bias.Comment: v3: minor changes matching published versio

Inter-rater agreement and reliability of the COSMIN (COnsensus-based Standards for the selection of health status Measurement Instruments) Checklist

<p>Abstract</p> <p>Background</p> <p>The COSMIN checklist is a tool for evaluating the methodological quality of studies on measurement properties of health-related patient-reported outcomes. The aim of this study is to determine the inter-rater agreement and reliability of each item score of the COSMIN checklist (n = 114).</p> <p>Methods</p> <p>75 articles evaluating measurement properties were randomly selected from the bibliographic database compiled by the Patient-Reported Outcome Measurement Group, Oxford, UK. Raters were asked to assess the methodological quality of three articles, using the COSMIN checklist. In a one-way design, percentage agreement and intraclass kappa coefficients or quadratic-weighted kappa coefficients were calculated for each item.</p> <p>Results</p> <p>88 raters participated. Of the 75 selected articles, 26 articles were rated by four to six participants, and 49 by two or three participants. Overall, percentage agreement was appropriate (68% was above 80% agreement), and the kappa coefficients for the COSMIN items were low (61% was below 0.40, 6% was above 0.75). Reasons for low inter-rater agreement were need for subjective judgement, and accustom to different standards, terminology and definitions.</p> <p>Conclusions</p> <p>Results indicated that raters often choose the same response option, but that it is difficult on item level to distinguish between articles. When using the COSMIN checklist in a systematic review, we recommend getting some training and experience, completing it by two independent raters, and reaching consensus on one final rating. Instructions for using the checklist are improved.</p

Hunting for Primordial Non-Gaussianity in the Cosmic Microwave Background

Since the first limit on the (local) primordial non-Gaussianity parameter, fNL, was obtained from COBE data in 2002, observations of the CMB have been playing a central role in constraining the amplitudes of various forms of non-Gaussianity in primordial fluctuations. The current 68% limit from the 7-year WMAP data is fNL=32+/-21, and the Planck satellite is expected to reduce the uncertainty by a factor of four in a few years from now. If fNL>>1 is found by Planck with high statistical significance, all single-field models of inflation would be ruled out. Moreover, if the Planck satellite finds fNL=30, then it would be able to test a broad class of multi-field models using the four-point function (trispectrum) test of tauNL>=(6fNL/5)^2. In this article, we review the methods (optimal estimator), results (WMAP 7-year), and challenges (secondary anisotropy, second-order effect, and foreground) of measuring primordial non-Gaussianity from the CMB data, present a science case for the trispectrum, and conclude with future prospects.Comment: 33 pages, 4 figures. Invited review, accepted for publication in the CQG special issue on nonlinear cosmological perturbations. (v2) References added. More clarifications are added to the second-order effect and the multi-field consistency relation, tauNL>=(6fNL/5)^2

A systematic review with procedural assessments and meta-analysis of Low Level Laser Therapy in lateral elbow tendinopathy (tennis elbow)

<p>Abstract</p> <p>Background</p> <p>Recent reviews have indicated that low level level laser therapy (LLLT) is ineffective in lateral elbow tendinopathy (LET) without assessing validity of treatment procedures and doses or the influence of prior steroid injections.</p> <p>Methods</p> <p>Systematic review with meta-analysis, with primary outcome measures of pain relief and/or global improvement and subgroup analyses of methodological quality, wavelengths and treatment procedures.</p> <p>Results</p> <p>18 randomised placebo-controlled trials (RCTs) were identified with 13 RCTs (730 patients) meeting the criteria for meta-analysis. 12 RCTs satisfied half or more of the methodological criteria. Publication bias was detected by Egger's graphical test, which showed a negative direction of bias. Ten of the trials included patients with poor prognosis caused by failed steroid injections or other treatment failures, or long symptom duration or severe baseline pain. The weighted mean difference (WMD) for pain relief was 10.2 mm [95% CI: 3.0 to 17.5] and the RR for global improvement was 1.36 [1.16 to 1.60]. Trials which targeted acupuncture points reported negative results, as did trials with wavelengths 820, 830 and 1064 nm. In a subgroup of five trials with 904 nm lasers and one trial with 632 nm wavelength where the lateral elbow tendon insertions were directly irradiated, WMD for pain relief was 17.2 mm [95% CI: 8.5 to 25.9] and 14.0 mm [95% CI: 7.4 to 20.6] respectively, while RR for global pain improvement was only reported for 904 nm at 1.53 [95% CI: 1.28 to 1.83]. LLLT doses in this subgroup ranged between 0.5 and 7.2 Joules. Secondary outcome measures of painfree grip strength, pain pressure threshold, sick leave and follow-up data from 3 to 8 weeks after the end of treatment, showed consistently significant results in favour of the same LLLT subgroup (p < 0.02). No serious side-effects were reported.</p> <p>Conclusion</p> <p>LLLT administered with optimal doses of 904 nm and possibly 632 nm wavelengths directly to the lateral elbow tendon insertions, seem to offer short-term pain relief and less disability in LET, both alone and in conjunction with an exercise regimen. This finding contradicts the conclusions of previous reviews which failed to assess treatment procedures, wavelengths and optimal doses.</p

Testing of cryogenic photomultiplier tubes for the MicroBooNE experiment

The MicroBooNE detector, to be located on axis in the Booster Neutrino Beamline (BNB) at the Fermi National Accelerator Laboratory (Fermilab), consists of two main components: a large liquid argon time projection chamber (LArTPC), and a light collection system. Thirty-two 8-inch diameter Hamamatsu R5912-02mod cryogenic photomultiplier tubes (PMTs) will detect the scintillation light generated in the liquid argon (LAr). This article first describes the MicroBooNE PMT performance test procedures, including how the light collection system functions in the detector, and the design of the PMT base. The design of the cryogenic test stand is then discussed, and finally the results of the cryogenic tests are reported

Optimising corticosteroid injection for lateral epicondylalgia with the addition of physiotherapy: A protocol for a randomised control trial with placebo comparison

<p>Abstract</p> <p>Background</p> <p>Corticosteroid injection and physiotherapy are two commonly prescribed interventions for management of lateral epicondylalgia. Corticosteroid injections are the most clinically efficacious in the short term but are associated with high recurrence rates and delayed recovery, while physiotherapy is similar to injections at 6 weeks but with significantly lower recurrence rates. Whilst practitioners frequently recommend combining physiotherapy and injection to overcome harmful effects and improve outcomes, study of the benefits of this combination of treatments is lacking. Clinicians are also faced with the paradox that the powerful anti-inflammatory corticosteroid injections work well, albeit in the short term, for a non-inflammatory condition like lateral epicondylalgia. Surprisingly, these injections have not been rigorously tested against placebo injections. This study primarily addresses both of these issues.</p> <p>Methods</p> <p>A randomised placebo-controlled clinical trial with a 2 × 2 factorial design will evaluate the clinical efficacy, cost-effectiveness and recurrence rates of adding physiotherapy to an injection. In addition, the clinical efficacy and adverse effects of corticosteroid injection beyond that of a placebo saline injection will be studied. 132 participants with a diagnosis of lateral epicondylalgia will be randomly assigned by concealed allocation to one of four treatment groups – corticosteroid injection, saline injection, corticosteroid injection with physiotherapy or saline injection with physiotherapy. Physiotherapy will comprise 8 sessions of elbow manipulation and exercise over an 8 week period. Blinded follow-up assessments will be conducted at baseline, 4, 8, 12, 26 and 52 weeks after randomisation. The primary outcome will be a participant rating of global improvement, from which measures of success and recurrence will be derived. Analyses will be conducted on an intention-to-treat basis using linear mixed and logistic regression models. Healthcare costs will be collected from a societal perspective, and along with willingness-to-pay and quality of life data will facilitate cost-effectiveness and cost-benefit analyses.</p> <p>Conclusion</p> <p>This trial will utilise high quality trial methodologies in accordance with CONSORT guidelines. Findings from this study will assist in the development of evidence based practice recommendations and potentially the optimisation of resource allocation for rehabilitating lateral epicondylalgia.</p> <p>Trial registration</p> <p>Australian New Zealand Clinical Trials Register ACTRN12609000051246</p