Hybrid simulation scheme for volatility modulated moving average fields

We develop a simulation scheme for a class of spatial stochastic processes called volatility modulated moving averages. A characteristic feature of this model is that the behaviour of the moving average kernel at zero governs the roughness of realisations, whereas its behaviour away from zero determines the global properties of the process, such as long range dependence. Our simulation scheme takes this into account and approximates the moving average kernel by a power function around zero and by a step function elsewhere. For this type of approach the authors of [8], who considered an analogous model in one dimension, coined the expression hybrid simulation scheme. We derive the asymptotic mean square error of the simulation scheme and compare it in a simulation study with several other simulation techniques and exemplify its favourable performance in a simulation study

Effect of sport-tinted contact lenses for contrast enhancement on retinal straylight measurements

PURPOSE: To investigate the effect of two tinted contact lenses (CL) designed for outdoor sports activity on the psychometric determination of retinal straylight using the compensation comparison method. METHODS: Thirteen emmetropic subjects were randomly fitted with two different tinted Nike Maxsight (Bausch & Lomb, Rochester, NY, USA) CL in one eye, while the contralateral eye was fitted with a clear lens made of the same material (Optima 38, Bausch & Lomb). Three valid straylight measurements were taken on each eye before and a few minutes after lens insertion, when lens stabilization had occurred. RESULTS: The subjects' mean straylight values were 0.90 +/- 0.09 at baseline and 0.95 +/- 0.10 with the clear Optima 38 CL. Straylight values were 0.97 +/- 0.10 and 1.0 +/- 0.10 log units with the amber and grey-green tinted CL, respectively. Differences in straylight between baseline (without CL) and with the clear CL in place were neither statistically significant (p = 0.066) nor was there a significant difference between baseline and the amber CL (p = 0.052). However, the grey-green CL showed a statistically significant difference from baseline (p = 0.006). Differences in straylight with the clear CL compared with the grey-green CL were also statistically different from zero (p = 0.002) showing an increased straylight value for the tinted CL. These differences were variable, but consistent for each subject, thus those showing higher or lower changes with one tinted lens tended to show the same trend with the second lens (r(2) = 0.736). CONCLUSIONS: Despite increases having been found in straylight values with tinted contact lenses, those changes are not likely to induce clinically significant changes in visual function under photopic conditions, even for the grey-green CL, which seems to increase straylight values more significantly than the amber CL. This difference between the tinted CL could suggest a wavelength dependence of straylight values, although this should be investigated further by controlling for pupil size and subjects' pigmentation, as well as by using neutral density filters

Communicating climate change risk: A content analysis of ipcc\u27s summary for policymakers

This study investigated the effectiveness of climate change risk communication in terms of its theoretical potential to stimulate recipients\u27 awareness and behavioral change. We selected the summary for policy makers (SPM) of the most recent Intergovernmental Panel on Climate Change (IPCC) report in order to conduct a content analysis; the extended parallel process model and construal level theory served as conceptual lenses to perform the analysis. Specifically, we evaluated to what extent the SPM included informational elements of threat, efficacy and psychological distance related to climate change. The results showed that threat information was prominently present, but efficacy information was less frequently included, and when it was, more often in the latter parts of the SPM. With respect to construal level it was found that in the IPCC report concrete representations were used only sparingly. Theoretical relevance and implications for climate change risk communication with key audiences are discussed

Atmospheric Drivers of Wind Turbine Blade Leading Edge Erosion: Review and Recommendations for Future Research

Leading edge erosion (LEE) of wind turbine blades causes decreased aerodynamic performance leading to lower power production and revenue and increased operations and maintenance costs. LEE is caused primarily by materials stresses when hydrometeors (rain and hail) impact on rotating blades. The kinetic energy transferred by these impacts is a function of the precipitation intensity, droplet size distributions (DSD), hydrometeor phase and the wind turbine rotational speed which in turn depends on the wind speed at hub-height. Hence, there is a need to better understand the hydrometeor properties and the joint probability distributions of precipitation and wind speeds at prospective and operating wind farms in order to quantify the potential for LEE and the financial efficacy of LEE mitigation measures. However, there are relatively few observational datasets of hydrometeor DSD available for such locations. Here, we analyze six observational datasets from spatially dispersed locations and compare them with existing literature and assumed DSD used in laboratory experiments of material fatigue. We show that the so-called Best DSD being recommended for use in whirling arm experiments does not represent the observational data. Neither does the Marshall Palmer approximation. We also use these data to derive and compare joint probability distributions of drivers of LEE; precipitation intensity (and phase) and wind speed. We further review and summarize observational metrologies for hydrometeor DSD, provide information regarding measurement uncertainty in the parameters of critical importance to kinetic energy transfer and closure of data sets from different instruments. A series of recommendations are made about research needed to evolve towards the required fidelity for a priori estimates of LEE potential.publishedVersio

Health state utilities for infertility and subfertility

Background: Health state utility values allow for comparison of treatments across different diseases. Utility values for fertility-impaired health states are currently unavailable. Such values are necessary in order to determine the relative costs-effectiveness of fertility treatments. Methods: This study aimed to determine utility weights for infertile and subfertile health states. In addition, it explored the Dutch general population’s opinions regarding the inclusion of infertility treatments in the Dutch health insurers’ basic benefit package. An online questionnaire was designed to determine the health-related quality of life values of six fertility-impaired health states. The study population consisted of a representative sample of the Dutch adult population. Respondents were asked to evaluate the health states through direct health valuation methods, i.e. the Visual Analogue Scale (VAS) and the Time Trade-Off (TTO) method. In addition, respondents were asked about their opinions regarding reimbursement of fertility-related treatments. Results: The respondents’ (n = 767) VAS scores ranged from 0.640 to 0.796. TTO utility values ranged from 0.792 to 0.868. Primary infertility and subfertility was valued lower than secondary infertility and subfertility. In total, 92% of the respondents stated that fertility treatments should be fully or partially reimbursed by the health insurance basic benefit package. Conclusions: Having fertility problems results in substantial disutilities according to the viewpoint of the Dutch general population. The results make it possible to compare the value for money of infertility treatment to that of treatments in other disease areas. There is strong support among the general population for reimbursing fertility treatments through the Dutch basic benefit package

Automatic Morphometry of Nerve Histological Sections

A method for the automatic segmentation, recognition and measurement of neuronal myelinated fibers in nerve histological sections is presented. In this method, the fiber parameters i.e. perimeter, area, position of the fiber and myelin sheath thickness are automatically computed. Obliquity of the sections may be taken into account. First, the image is thresholded to provide a coarse classification between myelin and non-myelin pixels. Next, the resulting binary image is further simplified using connected morphological operators. By applying semantic rules to the zonal graph axon candidates are identified. Those are either isolated or still connected. Then, separation of connected fibers is performed by evaluating myelin sheath thickness around each candidate area with an Euclidean distance transformation. Finally, properties of each detected fiber are computed and false positives are removed. The accuracy of the method is assessed by evaluating missed detection, false positive ratio and comparing the results to the manual procedure with sampling. In the evaluated nerve surface, a 0.9% of false positives was found, along with 6.36% of missed detections. The resulting histograms show strong correlation with those obtained by manual measure. The noise introduced by this method is significantly lower than the intrinsic sampling variability. This automatic method constitutes an original tool for morphometrical analysis

El Mañana: Año II Número 9 - (09/01/29)

There is no consensus on the treatment of multifocal primary cutaneous anaplastic large cell lymphoma (C-ALCL). Radiotherapy (RT) and methotrexate (MTX) are the current treatment options, but their efficacy is unknown. Recently, targeted therapies showed promising results in C-ALCL, and may therefore be an attractive first choice of treatment. To assess the efficacy of conventional treatment strategies for patients with multifocal C-ALCL, and to define which patients may require novel targeted therapies. In this multicenter study, treatment was evaluated in patients initially presenting (n=24) or relapsing with multifocal C-ALCL (n=17; 23 relapses). Distinction was made between cases with ≤ 5 (n=36) and >5 lesions (n=11). Treatments most commonly used were radiotherapy (n=21), systemic chemotherapy (n=9) and low-dose methotrexate (MTX; n=7) with complete response rates of 100%, 78% and 43%, respectively, and an overall response rate of 100%, 100%, and 57%, respectively. Four patients showed a complete spontaneous regression. Sixteen of 24 patients (67%) first presenting with multifocal C-ALCL relapsed, including all five patients initially treated with CHOP. Compared with patients presenting with 2-5 skin lesions, patients presenting with >5 lesions had a higher chance of developing extracutaneous relapse (56 vs 20%) and more often died of lymphoma (44% vs 7%). Patients with ≤5 lesions should be treated with low-dose RT (2x4 Gy). Maintenance low-dose MTX (20 mg/week) is a suitable option in patients with >5 lesions. Targeted therapies may be considered in rare patients refractory to MTX or patients developing extracutaneous disease. This article is protected by copyright. All rights reserve