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[en] Objective: Using raw, sub-second-level accelerometry data, we propose and validate a method for identifying and characterizing walking in the free-living environment. We focus on sustained harmonic walking (SHW), which we define as walking for at least 10 s with low variability of step frequency. Approach: We utilize the harmonic nature of SHW and quantify the local periodicity of the tri-axial raw accelerometry data. We also estimate the fundamental frequency of the observed signals and link it to the instantaneous walking (step-to-step) frequency (IWF). Next, we report the total time spent in SHW, number and durations of SHW bouts, time of the day when SHW occurred, and IWF for 49 healthy, elderly individuals. Main results: The sensitivity of the proposed classification method was found to be 97%, while specificity ranged between 87% and 97% and the prediction accuracy ranged between 94% and 97%. We report the total time in SHW between 140 and 10 min d−1 distributed between 340 and 50 bouts. We estimate the average IWF to be 1.7 steps-per-second. Significance: We propose a simple approach for the detection of SHW and estimation of IWF, based on Fourier decomposition. (note)
[en] Middle-aged marathon runners have an increased risk of developing atrial fibrillation (AF). A previous study described that repetitive marathon running was associated with left atrial (LA) dysfunction. However, whether this change is common in marathon runners and which runners are at risk of LA dysfunction remain unknown. The purpose of this study was to determine which factors could predict LA dysfunction. We prospectively examined 12 healthy amateur volunteers (9 males, 31 ± 8 years old) who participated in a full marathon. All echocardiographic measurements and speckle-tracking echocardiography were performed before and after the marathon. The endpoint was defined as reduced LA reservoir strain 1 day after the marathon (non-responder group). Seven participants were in the non-responder group. Age (35 ± 9 vs. 26 ± 2 years, p = 0.020), augmentation index (76 ± 12 vs. 55 ± 8, p = 0.002), and diastolic blood pressures (83 ± 11 vs. 70 ± 7 mmHg, p = 0.021) in the non-responder group were significantly higher compared with the responder group. In multivariate linear regression analysis, only the augmentation index was an independent predictor of reduced LA reservoir function after the marathon (β = − 0.646, p = 0.023). The augmentation index was a predictive marker for reduction in LA reservoir function after a marathon in healthy amateur volunteers.
[en] The development of two radioactivity-in-soil reference materials is described – one for peat and one for soil with high sand content. Each bulk material was processed, subdivided and measured before being sent to participants in an NPL Environmental Radioactivity Proficiency Test Exercise. Activity concentrations of radionuclides in each material were determined by ‘consensus’ evaluations of participants’ results using two weighted mean methods. The project demonstrated the use of such exercises in delivering reference materials to the user community. - Highlights: • Two radioactivity-in-soil reference materials have been developed. • Activity concentration data were collated from 21 laboratories. • Weighted means were calculated using two methods.
[en] A real-time internal dose assessment exercise has been conducted in which participants were required to make decisions about sampling requirements, seek relevant information about the 'incident' and make various interim dose assessments. At the end of the exercise, each participant was requested to make a formal assessment, providing statements of the methods, models and assumptions used in that assessment. In this paper we describe how the hypothetical assessment case was set up and the exercise was conducted, the responses of the participants and the assessments of dose that they made. Finally we discuss the lessons learnt from the exercise and suggest how the exercise may be adapted to a wider range of participants. (authors)
[en] This paper is focused on innovation of laboratory exercises in course Distributed Systems and Computer Networks. These exercises were introduced in November of 2012 and replaced older exercises in order to reflect real life applications
[en] Background: It is evident that a growing number of studies advocate a wrist-worn accelerometer for the assessment of patterns of physical activity a priori, yet the veracity of this site rather than any other body-mounted location for its accuracy in classifying activity is hitherto unexplored. Objective: The objective of this review was to identify the relative accuracy with which physical activities can be classified according to accelerometer site and analytical technique. Methods: A search of electronic databases was conducted using Web of Science, PubMed and Google Scholar. This review included studies written in the English language, published between database inception and December 2017, which characterized physical activities using a single accelerometer and reported the accuracy of the technique. Results: A total of 118 articles were initially retrieved. After duplicates were removed and the remaining articles screened, 32 full-text articles were reviewed, resulting in the inclusion of 19 articles that met the eligibility criteria. Conclusion: There is no ‘one site fits all’ approach to the selection of accelerometer site location or analytical technique. Research design and focus should always inform the most suitable location of attachment, and should be driven by the type of activity being characterized. (topical review)
[en] The purpose of this study was to compare the effects of laser photobiomodulation therapy (lPBMt) and ultrasound therapy (UST) in patients with chronic non-specific low back pain (CNLBP). Forty-five patients with CNLBP aged 30–40 years were divided randomly into three groups of 15 subjects each. The lPBMt group received 8 weeks of lPBMt with an exercise program, while the UST group received 8 weeks of UST with the same exercise program; the control group received only the exercise program for 8 weeks. Pain, disability, functional performance, and lumbar range of motion were assessed at the beginning of the study and after 8 weeks. There were no significant differences in demographic and clinical characteristics among the three groups at baseline (p > 0.05). At the end of the study, there were significant improvements in pain, disability, and functional performance in the two experimental groups (p < 0.05), but changes in the control group were non-significant. However, lumbar range of motion was significantly improved only in the lPBMt group (p < 0.05). When the three groups were compared in terms of a change in clinical variables, there was a significant difference among the three groups in all measures in favor of lPBMt group. Based on our results, both lPBMt or UST combined with an 8-week exercise program seemed to be effective methods for decreasing pain, reducing disability, and increasing functional performance in patients with CNLBP, although lPBMt is more effective than UST.
[en] The particle-in-the-box, with or without an additional potential, is proposed as an excellent laboratory to teach and explore the details of the linear variational method using a non-orthogonal basis. The xn(a - x)n and xn(a/2 - x)(a - x)n polynomials are shown to form a complete basis for the even and odd states, respectively, of the particle confined to the x in [0, a] interval. A short and simple Octave code is presented as the natural extension to the hand calculations when the basis set grows in size.