Polymer materials are increasingly widely used in high-fire-risk applications, such as aviation interior components. This study aimed to compare the tensile, thermal, and flame-retardant properties of test samples made from ultra-performance materials, polyetherimide (PEI) and polyetherketoneketone (PEKK), using the fused filament fabrication process (FFF). The tensile tests were performed for these materials at different raster angles (0, 45, and 90°). The thermomechanical tests were done in the axial, perpendicular, and through-thickness directions to the extruded filaments. The impact of printing parameters on the flame retardancy of 3D-printed samples was investigated in vertical burn tests with varying specimen thicknesses and printing directions. Experimentally, it was testified that PEKK had better isotropic behaviour than PEI for mechanical performance, thermal expansion, and fire-resistant properties, which are essential in fabricating intricately shaped products.

Introduction. Despite its importance for sports, the problem of the interaction of genetic and environmental factors affecting sports results in competitions is still not fully understood. This study aimed to evaluate the effect of walking in nature on stress levels and performance of taekwondo athletes during the competition period. Materials and Methods. The participants of this study were 12 Latvian taekwondo athletes, including males (n = 6) and females (n = 6), aged 17-23. The experiment was held four weeks before the International Sweden Taekwondo Competition (2022). The participants underwent twelve training sessions, including 40 minutes of walking in nature, in zones 1 and 2 (HR 101-141 bpm). The Depression and Anxiety Stress Scale questionnaire, gas discharge visualization, and the Determination Test were used to measure the stress levels. The data were analyzed using the mean, standard deviations, the Shapiro-Wilk test, paired sample t-test, and Wilcoxon signed-rank test. Results. The results of the paired sample t-test and Wilcoxon signed-rank test showed that walking in nature significantly affects stress levels ( DASS questionnaire, W = 78.00, as a p-value of 0.002 is < 0.05, gas discharge visualization, t(11) = 8.420, as a p-value of 0.001 is < 0.05, and the Determination Test, t(11) = −5.116, as a p-value of 0.001 is < 0.05) at the 5% level. Conclusions. The findings support visiting natural environments by walking in nature as a potentially helpful activity in taekwondo athletes’ strategy to reduce stress levels. Thus, while coaches may choose different strategies or activities to reduce stress, for many athletes, walking in nature and natural environments helps reduce stress levels.

The theory of basic emotions posits that a set of fundamental emotions—happiness, sadness, anger, fear, disgust, and surprise—are associated with universally recognizable facial expressions. One method for studying facial expressions is the Facial Action Coding System (FACS), which allows researchers to measure facial muscles to identify the emotions expressed by participants. Preschool is an important period for the development of kids and their ability to understand emotions. In this stage, children’s physical activity (PA) levels tend to decrease significantly, with children spending more time sedentary, such as sitting for six to eight hours a day and engaging in screen-based activities. The present study aimed to assess the basic emotional states and neutral levels of preschoolers (aged 5–6 years) participating in outdoor activities, using FaceReader (FR) as a facial emotion analysis tool. The results indicate that the outdoor activity intervention had a significant impact on the emotional states of the experimental group (EG), with marked reductions in sadness (p = .002) and disgust (p = .01), as well as significant increases in valence (p = .01) and arousal (p = .004). These findings showed the importance of outdoor activities in reducing negative emotions among preschool-aged children.

Breathing exercises are widely used to enhance respiratory function and athletic performance. This study aimed to assess the efficacy of a modified exercise regimen on respiratory parameters and its effect on the performance of young swimmers in competition. Thirty-one swimmers aged 16–17 from various clubs in Latvia were selected, comprising an experimental group (n = 15, height: 174.36 ± 7.85 cm, weight: 65.80 ± 9.35 kg, body mass index: 21.60 ± 1.54) and a control group (n = 16, height: 180.78 ± 7.05 cm, weight: 69.90 ± 6.49 kg, body mass index: 21.40 ± 1.56). With an average of eight years of experience, participants trained for approximately 43–45 weeks annually (pool and gym sessions), with an average training duration of 20 ± 2 hours per week. Measurements were conducted on days one and 30, involving spirometry and swimming performance assessment based on the best results in the freestyle 100-meter distance. The experiment consisted of a modified breathing exercise performed thrice weekly for four weeks. Significant improvements were observed in the experimental group compared to the control group in forced vital capacity (p = 0.02), peak inspiratory flow (p = 0.001), and performance (p = 0.001), with p-values < 0.05. However, no significant changes were noted in peak expiratory flow (p = 0.46 > 0.05). The findings indicate that modified breathing exercises effectively enhance respiratory parameters and performance in competitive swimmers.

This pilot study examined the effects of a 12-week reaction training program on physical and cognitive performance (choice reaction) in U20 Latvian fencers. Five qualified right-handed male fencers (aged 14.8–18.6 years) completed the Vienna Test System choice reaction task at baseline and after 12 weeks while cycling through five heart rate zones (1–5). Reaction speed (RS), motor speed (MS), choice reaction time (CR), and heart rate (HR) were recorded. Paired-sample t-tests indicated no significant group-level changes: RS (t = 1.46, p = 0.21, d = 0.65, 95% CI [−36.92, 118.92]), MS (t = 2.37, p = 0.07, d = 1.06, 95% CI [−3.14, 40.34]), CR (t = 1.70, p = 0.16, d = 0.76, 95% CI [−37.30, 156.26]), and HR (t = −2.69, p = 0.054, d = −1.20, 95% CI [−12.53, 0.17]). Individual responses revealed that three athletes improved CR in low- to moderate-intensity zones (−12.66% to −27.18%), whereas heart rate increased modestly (1.35% to 9.60%). Given the critical age for developing choice reaction, these findings should be considered as preliminary and exploratory, offering initial insights into how training might influence cognitive performance in young fencers and demonstrating that responses can differ across heart rate zones and among individuals.

In the context of global digital transformation, countries are adapting school curricula and improving students' digital literacy. Together with students' active engagement in digital environments, these findings support the growing role of digital literacy. Although the integration of digital literacy into school curricula is widely acknowledged, there is a lack of consensus regarding the definitions and implementations of the concept. Additionally, there is limited research on the concept of digital literacy in the context of general school education. This qualitative systematic review primarily aims to address this lack of clarity by analysing two questions: (1) how is the concept of digital literacy defined and applied in the research literature within the context of general school education, and (2) what underlying reasons contribute to its diverse interpretations? A review of scientific articles on the practical implementation of digital literacy was conducted, utilising the following databases: EBSCOhost, Scopus, and Web of Science. Sixteen articles that met the search criteria were analysed and conceptualised. The first research question was answered by identifying and formulating eight conceptual categories of digital literacy within general school education: digital tools, ethics, pedagogy, information, cognitive domain, emotional domain, social domain, and individual domain. The second research question was answered as follows: context dependence and various perspectives were proposed as potential causes for the diversity of definitions. The findings of this study clarify the concept of digital literacy by enriching existing frameworks with new, significant categories, thereby supporting its integration into general school education. Additionally, it contributes to the ongoing discourse on digital literacy in school education and highlights the need for future research to explore its application across various educational subjects.