Reliability analysis of time series force plate data of community dwelling older adults

Frequency-based analysis of body sway has been used to distinguish between healthy young, healthy elderly adults and elderly adults with Huntingtons disease. Our aim was to assess the reliability of spectral-based outcomes of the centre of pressure (CoP) kinematics in order to determine if these outcomes could be tested for their capability to distinguish between elderly fallers and non-fallers in a future study. We have studied balance for 30 community dwelling healthy older adults 60 years or older. Four test conditions were used. Three successive trials were performed for each condition. CoP kinematics were estimated with a force platform with three strain gauges set in a triangular position. The frequency content of these signals was estimated. Intrasession correlation coefficients (ICC's) were then calculated for all test conditions. The reliability of the selected parameters varied between low and high (ICC 0.652-0.939). The ICC's for the narrow stance tests were higher compared to tests with normal standing conditions (0.771-0.94) to (0.652-0.865). The highest value was obtained in the high frequency band (0.939). These measures should be viewed with caution when screening geriatric patients because their reliability cannot always be assumed

Investigation of pre-structured GaAs surfaces for subsequent site-selective InAs quantum dot growth

In this study, we investigated pre-structured (100) GaAs sample surfaces with respect to subsequent site-selective quantum dot growth. Defects occurring in the GaAs buffer layer grown after pre-structuring are attributed to insufficient cleaning of the samples prior to regrowth. Successive cleaning steps were analyzed and optimized. A UV-ozone cleaning is performed at the end of sample preparation in order to get rid of remaining organic contamination

Power estimation for non-standardized multisite studies

AbstractA concern for researchers planning multisite studies is that scanner and T1-weighted sequence-related biases on regional volumes could overshadow true effects, especially for studies with a heterogeneous set of scanners and sequences. Current approaches attempt to harmonize data by standardizing hardware, pulse sequences, and protocols, or by calibrating across sites using phantom-based corrections to ensure the same raw image intensities. We propose to avoid harmonization and phantom-based correction entirely. We hypothesized that the bias of estimated regional volumes is scaled between sites due to the contrast and gradient distortion differences between scanners and sequences. Given this assumption, we provide a new statistical framework and derive a power equation to define inclusion criteria for a set of sites based on the variability of their scaling factors. We estimated the scaling factors of 20 scanners with heterogeneous hardware and sequence parameters by scanning a single set of 12 subjects at sites across the United States and Europe. Regional volumes and their scaling factors were estimated for each site using Freesurfer's segmentation algorithm and ordinary least squares, respectively. The scaling factors were validated by comparing the theoretical and simulated power curves, performing a leave-one-out calibration of regional volumes, and evaluating the absolute agreement of all regional volumes between sites before and after calibration. Using our derived power equation, we were able to define the conditions under which harmonization is not necessary to achieve 80% power. This approach can inform choice of processing pipelines and outcome metrics for multisite studies based on scaling factor variability across sites, enabling collaboration between clinical and research institutions

The EC-Earth3 Earth system model for the Coupled Model Intercomparison Project 6

The Earth system model EC-Earth3 for contributions to CMIP6 is documented here, with its flexible coupling framework, major model configurations, a methodology for ensuring the simulations are comparable across different high-performance computing (HPC) systems, and with the physical performance of base configurations over the historical period. The variety of possible configurations and sub-models reflects the broad interests in the EC-Earth community. EC-Earth3 key performance metrics demonstrate physical behavior and biases well within the frame known from recent CMIP models. With improved physical and dynamic features, new Earth system model (ESM) components, community tools, and largely improved physical performance compared to the CMIP5 version, EC-Earth3 represents a clear step forward for the only European community ESM. We demonstrate here that EC-Earth3 is suited for a range of tasks in CMIP6 and beyond.Peer reviewe

Intrasession reliability of force platform parameters in community-dwelling older adults

Objective: To investigate the intrasession reliability of center of pressure (COP) parameters calculated from force platform measurements. Design: A cross-sectional study. Setting: Gait and balance laboratory. Participants: Community-dwelling healthy older adults (N=63) above the age of 62 years (mean age, 78.74y). Interventions: Not applicable. Main Outcome Measures: COP was estimated from a force platform, and the following parameters were calculated: (1) the total length of the COP displacement, (2) area of sway, (3) length of the COP displacement in the sagittal plane, and (4) length of the COP displacement in the frontal plane. Intraclass correlation coefficients (ICCs) were calculated by using 3 successive trials with 4 different test conditions. The test conditions were (1) normative standing with eyes open, (2) normative standing with eyes closed, (3) narrow stance with eyes open, and (4) narrow stance with eyes closed. Results: The ICCs for the tests with eyes closed (0.710-0.946) were higher than those for tests with eyes open (0.841-0.945). The highest value was obtained for the vector sum of the COP during anteroposterior movement in narrow stance with eyes closed (0.946). The value .710 was the lowest of all parameters and was an outlier for the narrow stance with eyes closed test, which was otherwise very reliable. Conclusions: Eight of 16 calculated ICCs showed excellent reliability (>0.90). They can be recommended for further use in clinical trials. Tests with closed eyes were more reliable than tests with eyes open. We recommend using eyes closed test conditions when assessing static balance control. For these tests, all the calculated ICCs were over 0.90, except for measurements of sway area

Positioning, Structuring and Controlling with Nanoprecision

Abstract. Key industries such as the automotive, electronic, medical and laboratory technical industries have continually rising demands for precise manufacturing, handling and control techniques. This is true for the manufacture of injection nozzles for engines as indeed also for the irradiation of extremely fine wafer structures and in the field of scanning probe microscopy

New insights into the flow dynamics of a deep freshwater aquifer in the semi-arid and saline Cuvelai-Etosha Basin, Northern Namibia: Results of a multi-environmental tracer study

Study region: A paleo-megafan system of the Cubango River in the northern parts of the semi-arid Cuvelai-Etosha Basin, shared by Angola and Namibia. It hosts a deep freshwater aquifer, the so-called Kalahari-Ohangwena 2 (KOH-2), with the potential to resolve the imminent regional water supply shortages. Study focus: Hydrogeochemical and multi-environmental tracer studies incorporating the use of age tracers ¹⁴C, ³⁶Cl, ⁸¹Kr and ⁴He to determine the age of groundwater and provide insights into the flow dynamics of the KOH-2. New hydrological insights for the region: Stable water isotopes and noble gas thermometry show that in a period with higher rainfall and recharge, temperatures were at least 3 – 4 °C lower than today. Several arguments led to the conclusion that younger groundwater, possibly of an age of 35,000 years, is mixed with ancient saline pore water. These include: 1) the correlation of measured ³⁶Cl and ⁸¹Kr ratios, as well as ⁴He concentrations, using a binary mixing model, and 2) the substantial variation in ⁸¹Kr ages, ranging from 40,000 to 170,000 years, over relatively short distances—a phenomenon challenging to explain by advective groundwater flow equations. Consequently, the ages derived from ⁸¹Kr measurements serve as indicators of the extent of freshening and therefore describe mixing ages rather than absolute travel times.ISSN:2214-581

Restricted use of glycopeptides in paediatric cancer patients with fever and neutropenia

Until now, studies confirming the safety of glycopeptide restriction in the empirical treatment of prolonged fever and neutropenia included only nine children. In an open-label observational study, the use of teicoplanin in paediatric oncology patients was investigated. A period of unrestricted use (2001-2003) was compared with a second period (2004) following implementation of a restrictive treatment guideline. Empirical first-line treatment consisted of piperacillin/tazobactam; in 2004, fosfomycin was added after 72 h as the second-line combination instead of teicoplanin. In total, 213 episodes (n=163 in 2001-2003; n=50 in 2004) managed with teicoplanin or fosfomycin (only 2004) were eligible. Empirical treatment of fever of unknown origin with teicoplanin was reduced by 97%. In 2004, the mean length of stay was 0.4 days shorter, no infection-related death occurred and no vancomycin-resistant enterococci were detected. Restriction of empirical glycopeptides is safe in paediatric cancer patients after first-line treatment with piperacillin/tazobactam. Fosfomycin appears to offer a feasible and cost-saving alternative in second-line combination therapy