Masaryk University Journals / Časopisy Masarykovy univerzity
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Convergent and divergent predictors of extensive use time and problematic TikTok use
No full textShort videos on TikTok provided an entertaining pastime for 1.5 billion users worldwide in 2023. The increasing popularity of TikTok has generated considerable research interest in the psychological and social predictors of problematic use. However, recent empirical studies on Internet-based activities have found evidence that extensive time spent on TikTok is not necessarily problematic. This study explores convergent and divergent predictors of extensive and problematic TikTok use including demographics, psychological distress, and TikTok activities. A total of 618 Hungarian TikTok users (80.1% women, 18.8% men; Mage = 22.1 years, SD = 4.2) completed an online questionnaire. The unidimensional, six-item Problematic TikTok Use Questionnaire was developed, demonstrating good psychometric properties in terms of factor structure, reliability, and validity. Based on latent profile analysis, 3.07% of TikTok users were found to be at risk of problematic TikTok use. Using a structural equation model, it was found that symptoms of depression, anxiety, and stress had stronger associations with problematic use than with extensive time spent on TikTok. Exploring the Discover page and viewing content creators’ videos predicted only problematic use severity. Exploring the For You page and reading comments posted to others’ videos were the strongest predictors of both extensive use time and problematic use. These factors collectively explained a notable proportion of the variance of problematic use severity (45%). The findings provide a detailed picture of risky use patterns and extend knowledge of the differences between extensive use time and problematic TikTok use
Adaptation Period of Beginning Teachers from the Point of View of Strategic Documents – Czech Republic and Bavaria
No full textThe beginning teachers represent the most vulnerable group of the teaching population in the Czech Republic. This text aims to compare Czech strategic documents covering teacher’s induction with the German ones. In contrast to the Czech Republic, Germany has a functional and established system of support for beginning teachers during their induction period. This comparison considers the institutional and legislative framework from the perspective of the existing (German) and draft (Czech) documents. The efforts in the Czech Republic emphasise the importance of a “comprehensive system of professional support from a genuine functional induction” (Strategie 2030+). As an example of German ones, the text examines the strategic and legislative frameworkof Referendariat in Bavaria. The text assesses the documents in the following key areas: forms of support, the status and role of the “key stakeholders” (teachers, mentors, responsible persons etc.), the activities and interaction between the key stakeholders. 
Assessment of the Hamstring Load of Female Beach Volleyball Players of a Wider Representative Selection of the U16 Category During the Block Jump Using Surface Electromyography
Get PDFBlocking in beach volleyball appears to be an axisymmetric movement - in contrast to an attacking strike or serve, which stress the musculoskeletal system unilaterally. When jumping on a block, the player squats and jumps from this position, so we can say that it is a squat with a jump. In the pre-jump phase, the quadriceps femoris, hip extensors (gluteus maximus and hamstrings) and trunk extensors are engaged. This study deals with this game activity from the point of view of unilateral loading and the involvement of individual muscles in the course of jumping onto a block. The aim of the study is to evaluate the involvement of the hamstring muscle group in female beach volleyball players of a wider representative selection under 16 years (n = 11) average age 13.1 (SD = 0.67) and to find out whether this game activity of the individual is axially symmetrical, at the same time we will assess whether the biceps femoris muscle is more involved in the block jump or if it is the semitendinosus. The main method used was surface electromyography (EMG) and descriptive, inferential statistics methods. For the measurements, we used stable conditions, the blockers did not move, they stood directly against the ball, which was thrown by a member of the research team above the level of the net within the reach of the blocker. Results: the jump to the block is laterally symmetrical in 36% of attempts, in 45% of attempts the right leg is more loaded and in 18% the left leg. Biceps and semitendinosus participate equally in 27% of the block jump. In 27% of the group, the biceps femoris is more involved in this movement task, and in 27% of the cases, the semitendinosus is more involved. Despite the description of individual tendencies in the group, statistical significance was not confirmed in any phase of the movement for any muscle. We recommend a more detailed research solution to this issue
Leaf characteristics and morphophysiological features of selected vascular plants in goltsy deserts of the Khibiny Mountains (Kola Peninsula)
Get PDFThe stability of biota in the extreme conditions of the goltsy deserts during ongoing climate change is determined by the adaptive characteristics of individual species. This study aimed to assess the characteristics of vascular plants (Salix polaris, Salix hastata, Saxifraga oppositifolia, Carex bigelowii, and Luzula arcuata) to the conditions of existence in the Khibiny goltsy deserts. The assessment was based on the morphological and anatomical leaf structures, pigment content and the intensity of photosynthesis. Biomorphological adaptations of high-altitude plants include miniaturization, plagiotropy, and compactization. The leaves of the studied plant species in the goltsy deserts exhibit features characteristic of mesophytes and xerophytes. For deciduous shrubs, a dorsoventral leaf structure with a high palisade coefficient was observed. For herbaceous perennials, a homogeneous type of mesophyll structure with a uniform distribution of chloroplasts and a thick cuticle was observed. The chlorophyll and carotenoid content ranges were comparable to those of the same species in the Khibiny mountain tundra belt and the Arctic tundra of Western Svalbard, indicating genetic determinism in the chlorophyll content of these species. The highest values of photosynthetic activity were found in graminoids (Carex bigelowii and Luzula arcuata) and Salix polaris. The characteristics of these species provide greater stability in the extreme conditions of the goltsy deserts and under climate change. Saxifraga oppositifolia exhibited the lowest values of photosynthetic activity
The first phylogenetic and ecophysiological characterisation of Ankistrodesmus antarcticus CCAP 202/25, an Antarctic green alga isolated from freshwater ice
Get PDFGlacier ice algae and snow algae are important primary producers in extreme cold environments and significantly impact global processes through their role in carbon cycling and glacier melting by reducing surface albedo. These organisms have evolved unique cold-adaptation mechanisms, making them promising candidates for biotechnological applications, yet few species are characterised in detail. Such studies are also becoming particularly urgent, as polar cryospheric habitats are rapidly changing because of the ongoing climate change. Here we describe the phylogenetic placement and ecophysiological characterisation of the strain Ankistrodesmus antarcticus CCAP 202/25 that was isolated from a sample of green-coloured icicle collected on Sabrina Island (Balleny Islands, Antarctica). Cells maintained the size and shape that were reported in the original description of the strain in 1968. Analysis of the 18S rDNA confirmed its placement in the Selenastraceae family and, more specifically, in the highly supported and ecologically diversified Monoraphidium V clade, suggesting that a revision of its taxonomic assignment to the genus Ankistrodesmus will be necessary. Comparison of secondary structures of ITS2 rDNA uncovered several closely related strains with diverse or unknown origin that should be regarded as conspecific with Ankistrodesmus antarcticus CCAP 202/25. Therefore, more data are necessary to get a detailed insight into the phylogenetic and ecological diversification within this group. The cultivation of the strain in crossed gradients of temperature and light reflected adaptation of the species to cold Antarctic habitats. Similarly to psychrophilic species, Ankistrodesmus antarcticus was able to grow at 1°C, but the highest growth rates were recorded in a wide range of temperature (6–25°C) making its ecophysiological classification difficult. The ability of the species to utilise very low intensity (and simultaneously wide range) of photosynthetically active radiation also indicates its adaptation to a polar cryospheric habitat, where light availability can often represent the limiting factor, but significant fluctuations of irradiance can be common, both short-term and long-term
Sociolingvistický kontext činnosti Jana Husa : (analýza filmové adaptace Jan Hus podle stejnojmenného románu a scénáře Evy Kantůrkové)
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"Remédios supersticiosos para curar" : amuletos y talismanes del Siglo de Oro
No full textBased on a selection of words referring to amulets, talismans, and relics obtained from the CorLexIn corpus, we intend to offer a characterisation and description of their morphology and uses, based mainly on lexicographical sources close to the context of the 17th century, which will also allow to analyse their treatment in this context. In addition to the lexicographical work, we propose a document-based analysis using the data provided by the academic corpus, which offers a more general view, as opposed to the vision offered by CorLexIn, which has a more specialised profile and a closer perspective to the linguistic reality of the seventeenth-century period.A partir de una selección de voces alusivas a amuletos, talismanes y reliquias extraída a partir del corpus CorLexIn, pretendemos ofrecer una caracterización y descripción de su morfología y usos a partir, principalmente, de fuentes lexicográficas próximas al contexto del siglo XVII, que permitirá, asimismo, comprobar su tratamiento en este contexto. Complementario al trabajo lexicográfico, se propone un análisis de tipo documental a partir de los datos proporcionados por los corpus académicos — de carácter más general — frente a la visión que ofrecería CorLexIn, con un perfil más especializado y una visión más cercana a la realidad lingüística del periodo seiscentista