Who is a tired student? Fatigue and its predictors from a gender perspective

The level of fatigue among medical students is increasing. Exhaustion is an essential symptom of burnout, which may occur even while a student. Our exploratory study sought to identify the characteristics of tired students and to describe factors determining fatigue among medical students. The studied group consisted of second-year medical students (N=193) from a Polish medical university. Statistically significant differences in fatigue appeared between male and female students. We obtained positive correlations between intensity of fatigue and sleepiness, pain intensity, stress, anxiety, depression and negative health conditions, life satisfaction, emotional stability, conscientiousness, and self-efficacy. Predictors relevant for female fatigue were sleepiness, health condition, depression, and conscientiousness (the whole model explains 46% of variance in fatigue). Predictors relevant for male fatigue were sleepiness, health condition, anxiety, and agreeableness (the whole model explains 55% of variance in fatigue). We did not observe differences in fatigue between sleepless, overloaded, or stressed people. Explaining the differences between male and female predictors and levels of fatigue in terms of personality traits through the prism of defined stereotypical social roles is worth considering.

Spatial and Temporal Distribution of Bacterioplankton Molecular Ecological Networks in the Yuan River under Different Human Activity Intensity

Bacterioplankton communities play a crucial role in freshwater ecosystem functioning, but it is unknown how co-occurrence networks within these communities respond to human activity disturbances. This represents an important knowledge gap because changes in microbial networks could have implications for their functionality and vulnerability to future disturbances. Here, we compare the spatiotemporal and biogeographical patterns of bacterioplankton molecular ecological networks using high-throughput sequencing of Illumina HiSeq and multivariate statistical analyses from a subtropical river during wet and dry seasons. Results demonstrated that the lower reaches (high human activity intensity) network had less of an average degree (10.568/18.363), especially during the dry season, when compared with the upper reaches (low human activity intensity) network (10.685/37.552) during the wet and dry seasons, respectively. The latter formed more complexity networks with more modularity (0.622/0.556) than the lower reaches (high human activity intensity) network (0.505/0.41) during the wet and dry seasons, respectively. Bacterioplankton molecular ecological network under high human activity intensity became significantly less robust, which is mainly caused by altering of the environmental conditions and keystone species. Human activity altered the composition of modules but preserved their ecological roles in the network and environmental factors (dissolved organic carbon, temperature, arsenic, oxidation–reduction potential and Chao1 index) were the best parameters for explaining the variations in bacterioplankton molecular ecological network structure and modules. Proteobacteria, Actinobacteria and Bacteroidetes were the keystone phylum in shaping the structure and niche differentiations in the network. In addition, the lower reaches (high human activity intensity) reduce the bacterioplankton diversity and ecological niche differentiation, which deterministic processes become more important with increased farmland and constructed land area (especially farmland) with only 35% and 40% of the community variation explained by the neutral community model during the wet season and dry season, respectively. Keystone species in high human activity intensity stress habitats yield intense functional potentials and Bacterioplankton communities harbor keystone taxa in different human activity intensity stress habitats, which may exert their influence on microbiome network composition regardless of abundance. Therefore, human activity plays a crucial role in shaping the structure and function of bacterioplankton molecular ecological networks in subtropical rivers and understanding the mechanisms of this process can provide important information about human–water interaction processes, sustainable uses of freshwater as well as watershed management and conservation.

Numerical and Experimental Approach for Failure Analysis of Soil Subjected to Surface Explosion Loading

Controlling the hazards to facilities caused by detonation waves is a high priority in engineering design. To protect an underground facility, soil can reduce the destructive effects of detonation waves. Soil dynamic characteristics and the area of the destructive zone are affected by shock wave energy. The material at ground zero is impacted by high-intensity stress and forms a crater. To ensure the safety of the facility, the protective soil layers must be sufficiently thick. Therefore, the purpose of this study was to analyze the destructive effects that caused the deformation and destruction of an external protective soil layer. The results of the explosion experiments and the numerical simulation analysis were compared to explore the dynamic characteristics of the soil affected by the shock wave and the crater effects of on-ground explosions. The analysis model adopted an 8-node hexahedral element to create a three-dimensional solid structure model of the fluid-solid interaction. The material failure analysis demonstrated that the detonation wave destabilized the interior of the soil body, and the nearby high-intensity stress was the key factor for material failure. The results can serve as a reference for the design of soil-covering layers that provide explosion hazard control.

High-Performance Practice Processes

Despite their idiosyncrasies, motor and cognitive learning and endurance sports training have in common that they involve repeated practice. While considerable research has been devoted to the effect of practice on performance, little is known about optimal practice strategies. In this paper, we model the practice process for both skill acquisition and retention, and optimize its profile to maximize performance on a predefined date. For skill acquisition, we find that the optimal process involves multiple phases of practice increase and decrease, yielding U-shaped effort consistent with the principle of distributing practice, and that the transitions between phases are smoother for skills that are easily forgotten (e.g., cognitive skills) than for those that are easily retained (e.g., continuous motor skills). In particular for the latter, an extended period of rest should precede an ultimate high-intensity stress. For skill retention, the optimal practice strategy consists of cycles of either constant effort (for skills that are easily forgotten) or pulsed effort (for skills that are easily retained) consistent with the principle of alternating stress and rest. Our parametric model thus indicates when commonly used high-performance practice strategies are indeed optimal. This paper was accepted by Serguei Netessine, operations management.

Intensiivsus, rõhk ja välde eesti keeles

Uurimuses vaadeldakse, kas ja millised intensiivsuse parameetrid eristavad eesti keeles (a) lauserõhutut, lauserõhulist ja emfaatilise lauserõhuga sõna, (b) sõnarõhulist ja -rõhutut silpi ning (c) kolme väldet, ning kas võimalikud korrelatsioonid on sõltu matud põhitoonist. Intensiivsuse parameetritest on vaatluse all sõnarõhulise silbi intensiivsuse tase, intensiivsuse ulatus sõnas ja intensiivsuse kontuur rõhulises silbis. Uurimuse tulemusena leiti, et lause tasandi tingimusi ‒ lauserõhutut, lauserõhulist ja emfaatilise lauserõhuga sõna ‒ eristab üksteisest rõhulise silbi intensiivsuse tase, mis on tugevalt seotud rõhulise silbi põhitoonitasemega. Sõna tasandi tingimusi ‒ sõna rõhulist silpi ja välteastmeid ‒ eristavad intensiivsuse parameetrid seevastu on põhitoonist sõltumatumad. Sõnarõhulist silpi eristab rõhutust kõrgem intensiivsuse tase, ning välteastmeid eristavad intensiivsuse ulatus sõnas ja intensiivsusekontuur rõhulises silbis. Abstract. Heete Sahkai and Meelis Mihkla: Intensity, stress, and quantity in Estonian. The study examines the correlations of overall intensity with a) deaccented, accented and emphatically accented words; b) stressed and unstressed syllables; and c) short, long and overlong word quantities. The study considers three intensity parameters: the intensity level and the intensity contour of the stressed syllable, and the intensity range of the word. The authors ask whether and which of these parameters correlate with the examined categories, and whether the possible correlations are independent of fundamental frequency. The study finds that the phrase level categories – deaccented, accented, and emphatically accented words – are distinguished by the intensity level of the stressed syllable, which correlates strongly with F0. The intensity parameters that correlate with the word level categories are more independent of F0. The stressed syllable is distinguished from the unstressed syllable by a higher intensity level. The three quantity degrees are distinguished by the intensity range of the word and the intensity contour in the stressed syllable. Keywords: Estonian, word quantity, word stress, phrasal stress, emphasis, acoustic correlates, intensity, fundamental frequency

Longitudinal Functional Assessment of Brain Injury Induced by High-Intensity Ultrasound Pulse Sequences

Exposure of the brain to high-intensity stress waves creates the potential for long-term functional deficits not related to thermal or cavitational damage. Possible sources of such exposure include overpressure from blast explosions or high-intensity focused ultrasound (HIFU). While current ultrasound clinical protocols do not normally produce long-term neurological deficits, the rapid expansion of potential therapeutic applications and ultrasound pulse-train protocols highlights the importance of establishing a safety envelope beyond which therapeutic ultrasound can cause neurological deficits not detectable by standard histological assessment for thermal and cavitational damage. In this study, we assessed the neuroinflammatory response, behavioral effects, and brain micro-electrocorticographic (µECoG) signals in mice following exposure to a train of transcranial pulses above normal clinical parameters. We found that the HIFU exposure induced a mild regional neuroinflammation not localized to the primary focal site, and impaired locomotor and exploratory behavior for up to 1 month post-exposure. In addition, low frequency (δ) and high frequency (β, γ) oscillations recorded by ECoG were altered at acute and chronic time points following HIFU application. ECoG signal changes on the hemisphere ipsilateral to HIFU exposure are of greater magnitude than the contralateral hemisphere, and persist for up to three months. These results are useful for describing the upper limit of transcranial ultrasound protocols, and the neurological sequelae of injury induced by high-intensity stress waves.

Meta-analysis of the General Coral Stress Response: Acropora corals show opposing responses depending on stress intensity

As climate change progresses, reef-building corals must contend more often with suboptimal conditions, motivating a need to understand coral stress response. Here we test the hypothesis that there is a stereotyped transcriptional response that corals enact under any stressful conditions, functionally characterized by downregulation of growth and activation of cell death, response to reactive oxygen species, immunity, and protein homeostasis. We analyze RNA-seq and Tag-Seq data from 14 previously published studies and supplement them with four new experiments involving different stressors, totaling over 600 gene expression profiles from the genus Acropora. Contrary to expectations, we found not one, but two distinct types of response. The type A response was observed under all kinds of high-intensity stress, showed strong correlations between independent projects, and was functionally consistent with the hypothesized stereotyped response. Higher similarity of type A responses irrespective of stress type supports its role as the General Coral Stress Response providing a blanket solution to severely stressful conditions. The distinct type B response was observed under lower intensity stress and was weaker and more variable among studies than type A. Unexpectedly, the type B response was broadly opposite the type A response: biological processes up-regulated under type A response tended to be down-regulated under type B response, and vice versa. Gene network analysis indicated that type B response does not involve specific co-regulated gene groups and is simply the opposite of type A response. We speculate that these paradoxically opposing responses may result from an inherent negative association between stress response and cell proliferation.