1. 3D finite element analysis of a concrete dam behavior under changing hydrostatic load : a case studyPavel Žvanut, 2022, original scientific article Abstract: In this study, a large arch-gravity Moste Dam was analyzed, where an automated system for the measurements of horizontal displacements of the upper part of the dam was established. Two-dimensional (2D) and three-dimensional (3D) analyses of dam behavior, taking into account the earth pressures and the hydrostatic load, using the finite element method (FEM)-based computer program DIANA, were performed. The influence of lowering the water level of the reservoir by 6.2 m, on the horizontal displacements of the upper part of the dam, at stationary temperature conditions, was investigated. It was found that the results of the performed 2D and 3D FEM analyses fitted in very well with the result of experimentally determined measurement of horizontal displacements (which was 0.48 mm in the upstream direction) that was obtained using a hanging pendulum. An additional comparison of the results of 3D calculations showed that the finite element mesh density had a small effect on the calculated horizontal displacements.
Keywords: concrete dam, finite element method, material properties, structure behavior, measuring instruments, monitoring, ime series analysis, horizontal displacements, hydrostatic pressure
Published in DiRROS: 21.06.2023; Views: 345; Downloads: 194
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2. Sarcopenia parameters in active older adults – an eight-year longitudinal studyKaja Teraž, Uroš Marušič, Miloš Kalc, Boštjan Šimunič, Primož Pori, Bruno Grassi, Stefano Lazzer, Marco Vicenzo Narici, Mojca Gabrijelčič Blenkuš, Pietro Enrico Di Prampero, Carlo Reggiani, Angelina Passaro, Gianni Biolo, Mladen Gasparini, Rado Pišot, 2023, original scientific article Abstract: Background Sarcopenia is a common skeletal muscle syndrome that is common in older adults but can be mitigated by adequate and regular physical activity. The development and severity of sarcopenia is favored by several factors, the most influential of which are a sedentary lifestyle and physical inactivity. The aim of this observational longitudinal cohort study was to evaluate changes in sarcopenia parameters, based on the EWGSOP2 definition in a population of active older adults after eight years. It was hypothesized that selected active older adults would perform better on sarcopenia tests than the average population. Methods The 52 active older adults (22 men and 30 women, mean age: 68.4±5.6 years at the time of their first evaluation) participated in the study at two time points eight-years apart. Three sarcopenia parameters were assessed at both time points: Muscle strength (handgrip test), skeletal muscle mass index, and physical performance (gait speed), these parameters were used to diagnose sarcop0enia according to the EWGSOP2 definition. Additional motor tests were also performed at follow-up measurements to assess participants’ overall fitness. Participants self-reported physical activity and sedentary behavior using General Physical Activity Questionnaire at baseline and at follow-up measurements. Results In the first measurements we did not detect signs of sarcopenia in any individual, but after 8 years, we detected signs of sarcopenia in 7 participants. After eight years, we detected decline in ; muscle strength (-10.2%; p<.001), muscle mass index (-5.4%; p<.001), and physical performance measured with gait speed (-28.6%; p<.001). Similarly, self-reported physical activity and sedentary behavior declined, too (-25.0%; p=.030 and −48.5%; p<.001, respectively). Conclusions Despite expected lower scores on tests of sarcopenia parameters due to age-related decline, participants performed better on motor tests than reported in similar studies. Nevertheless, the prevalence of sarcopenia was consistent with most of the published literature. Trial registration The clinical trial protocol was registered on ClinicalTrials.gov, identifier: NCT04899531
Keywords: elderly, physical activities, sedentary behavior, skeletal muscle disorder, sarcopenia
Published in DiRROS: 29.05.2023; Views: 340; Downloads: 176
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3. The effect of menstrual cycle on perceptual responses in athletes : a systematic review with meta-analysisAna Carolina Paludo, Armin Paravlić, Kristýna Dvořáková, Marta Gimunová, 2022, review article Abstract: This article aimed to investigate the effects of menstrual cycle phases on perceptual responses in athletes by means of systematic review and meta-analysis. The search was conducted in the PubMed, Web of Science, and Sport Discus databases considering articles with two or more menstrual phases for comparison. The PECO criteria were used for the keywords “menstrual cycle,” “athletes,” and “perceptual responses” with their respective entry terms. Of 1.165 records identified, 14 articles were available for the final evaluation, while eight articles were eligible for a meta-analysis. The perceptual responses evaluated in the studies were: motivation, competitiveness, sleep quality, stress, muscle soreness, fatigue, perceived effort, mood, menstrual symptoms, perceived endurance, and readiness. The meta-analysis was conducted for perceived effort only. The results showed that the level of perceived exertion does not differ two phases of the menstrual cycle (MD = 3.03, Q = 1.58, df = 1, p = 0.209), whereas RPE was 19.81 ± 0.05 and 16.27 ± 0.53 at day 1–5 and day 19–24, respectively. Two studies found statistically significant changes in motivation and competitiveness during the cycle, with better outcomes in ovulatory phase compared to follicular and luteal. One study found an increase in mood disturbance in the pre-menstrual phase (vs. mid-cycle); one decreased vigor in the menstrual phase (vs. luteal); one increased the menstrual symptoms in the follicular phase (vs. ovulation), and one study reported increased fatigue and decreased sleep quality on luteal phase (vs. follicular). The remaining studies and variables were not affected by the menstrual cycle phase. Based on the results from the studies selected, some perceptual responses are affected in different menstrual cycle phases. A “favorable” subjective response in athletes was noticed when the ovarian hormones present an increase in concentration levels compared to phases with lower concentration. Different perceptual variables and methodological approaches limit the generalization of the conclusion.
Keywords: athletes, female, behavior, menstrual cycle, hormones, perceptual responses
Published in DiRROS: 19.07.2022; Views: 458; Downloads: 393
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5. Effect of CeO[sub]2 doping on the microstructure and corrosion behavior of CoCuNiTi high-entropy alloy coatingsMing-xing Ma, Liang Zhao, Zhi-xin Wang, Shang-zhi Li, Chen Dong, 2021, original scientific article Keywords: high-entropy alloy coating, CoCuNiTi, microstructure, corrosion behavior, laser cladding
Published in DiRROS: 06.05.2022; Views: 515; Downloads: 120
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6. Physical activity drops during summer holidays for 6- to 9-year-old childrenTadeja Volmut, Rado Pišot, Jurij Planinšec, Boštjan Šimunič, 2021, original scientific article Abstract: Regular physical activity (PA) reduces the health risk of childhood obesity and associated chronic diseases as well as mental health problems. Since PA declines as children age as well with future generations it is of highest importance to intervene in school and out-of-school settings. Out-of-school periods affect children's PA as it is mainly left to the interest and motivation of their parents. We compared accelerometer-based PA patterns in 93 6- to 9-year old children assessed four times: before (May/June), during (August), and after (September) summer holidays and at a 1-year follow up (May/June). Before summer holidays children were assessed also for anthropometry and motor tests. During summer holidays overall PA decreased by 18% (p < 0.001), physical inactivity increased by 5.5% (p < 0.001), moderate PA decreased by 53% (p < 0.001) and moderate to vigorous PA decreased by 45% (p < 0.001) when compared to before summer holidays. Furthermore, overall PA remained diminished also after summer holidays by 8.8% (p = 0.001) but recovered to baseline values at 1-year follow up. About 30% of overall PA and moderate to vigorous PA decrease during summer holidays could be explained by children's fitness level as a greater decrease was found in children with better results in standing long jump and 300-meter running time. Our finding detects an alarming summer holiday decrease in children PA that should not be neglected in future studies and intervention designs.
Keywords: MVPA, children, vacations, physical inactivity, sedentary behavior, accelerometer
Published in DiRROS: 19.01.2021; Views: 1115; Downloads: 989
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