Structural evolution of protein-biofilms: Simulations and experiments

The control of biofilm formation is a challenging goal that has not been reached yet in many aspects. One unsolved question is the role of van der Waals forces and another is the importance of mutual interactions between the adsorbing and the adsorbed biomolecules ("critical crowding"). In this study, a combined experimental and theoretical approach is presented, which fundamentally probes both aspects. On three model proteins-lysozyme, α-amylase, and bovine serum albumin-the adsorption kinetics is studied experimentally. Composite substrates are used enabling a separation of the short- and the long-range forces. Although usually neglected, experimental evidence is given for the influence of van der Waals forces on the protein adsorption as revealed by in situ ellipsometry. The three proteins were chosen for their different conformational stabilities in order to investigate the influence of conformational changes on the adsorption kinetics. Monte Carlo simulations are used to develop a model for these experimental results by assuming an internal degree of freedom to represent conformational changes. The simulations also provide data on the distribution of adsorption sites. By in situ atomic force microscopy we can also test this distribution experimentally, which opens the possibility to, e.g., investigate the interactions between adsorbed proteins.     

The Probability Ranking Principle Revisited

A theoretic framework for multimedia information retrieval is introduced which guarantees optimal retrieval effectiveness. In particular, a Ranking Principle for Distributed Multimedia-Documents (RPDM) is described together with an algorithm that satisfies this principle. Finally, the RPDM is shown to be a generalization of the Probability Ranking principle (PRP) which guarantees optimal retrieval effectiveness in the case of text document retrieval. The PRP justifies theoretically the relevance ranking adopted by modern search engines. In contrast to the classical PRP, the new RPDM takes into account transmission and inspection time, and most importantly, aspectual recall rather than simple recall.     

Early Crying,Sleeping, and Feeding Problems and Trajectories of Attention Problems From Childhood to Adulthood

This study investigated if crying, sleeping or feeding problems that co-occur (multiple regulatory problems [RPs]) or are persistent predict attention problems and diagnoses of attention deficit hyperactivity disorder (ADHD) in childhood and adulthood. Participants were 342 individuals who were assessed at 5, 20, and 56 months for crying, sleeping, and feeding (RPs) and at 6, 8, and 28 years for ADHD diagnoses, attention problems, and attention span. Infants/toddlers with multiple/persistent RPs had an increased risk of receiving an ADHD diagnosis both in childhood and adulthood compared to those who never had RPs. Multiple/persistent RPs were further associated with a high-decreasing attention problems trajectory from childhood to adulthood. Interventions to alleviate early RPs may prevent the development of attention problems.     

Effect of time-of-day-specific strength training on maximum strength and EMG activity of the leg extensors in men

In this study, we examined the effects of time-of-day-specific strength training on maximum strength and electromyography (EMG) of the knee extensors in men. After a 10-week preparatory training period (training times 17:00-19:00 h), 27 participants were randomized into a morning (07:00-09:00 h, n = 14) and an evening group (17:00-19.00 h, n = 13). Both groups then underwent 10 weeks of time-of-day-specific training. A matched control group (n = 7) completed all testing but did not train. Unilateral isometric knee extension peak torque (MVC) and one-repetition maximum half-squat were assessed before and after the preparatory training and after the time-of-day-specific training at times that were not training-specific (between 09:00 and 16:00 h). During training-specific hours, peak torque and EMG during MVC and submaximum isometric contraction at 40% MVC were assessed before and after the time-of-day-specific training. The main finding was that a significant diurnal difference (P < 0.01) in peak torque between the 07:00 and 17:00 h tests decreased after time-of-day-specific training in the morning group but not in the evening or control groups. However, the extent of this time-of-day-specific adaptation varied between individuals. Electromyography during MVC did not show any time-of-day-specific adaptation, suggesting that peripheral rather than neural adaptations are the main source of temporal specificity in strength training.     

Strategic timing of entry: evidence from video games

This paper investigates how video game publishers’ choice of game release date is affected by the expected level of competition within the game’s product niche. We identify game niches by genre, age-appropriateness, console system, a release cohort, and publisher. First, we show that games are more likely to be released so as to avoid weeks when their niche already faces competition. Next, we show that consumer substitution across games is stronger within most of the dimensions describing product niches. Sales volumes decay quickly after the opening weekend, so at any point in time, a niche will typically be served by few current titles. From this, we calculate that delaying game release 1 week yields substantial increase in revenue for a video game facing higher-than-average competition.     

Development of two short measures for recovery and stress in sport

The Acute Recovery and Stress Scale (ARSS) and the Short Recovery and Stress Scale were first established in German for the purposes of monitoring athletes’ current recovery-stress states in an economical and multidimensional manner. The aim of this paper is to document the development and initial validation of the English versions of these two psychometric monitoring tools. A total of 267 English-speaking athletes from a variety of team and individual sports participated in the study. The English versions demonstrated satisfactory internal consistency for both instruments (Cronbach α of .74–.89). Furthermore, good model fit was found for the eight scales of the ARSS, matching the structure and results of the German counterparts. Correlations among and between the scales reciprocate the theoretical constructs of stress and recovery, supporting the construct validity of the scales. Correlation coefficients within stress and recovery ranged between r_s?=?.29 and .68. The correlations between stress and recovery varied between r_s?=??.29 and ?.64. These constructs were further supported by correlations with the scores of the Recovery-Stress Questionnaire for Athletes, thereby showing convergent validity. The findings demonstrate initial validity and reliability of the two measures and reflect the results of the German versions. However, further research is needed before applying these scales in practical settings.     

Physical activity,sedentary behaviour,and socioeconomic status among Finnish girls and boys aged 6–8 years

We studied differences in physical activity (PA), sedentary behaviour (SB), and the types of PA and SB between Finnish girls and boys and children from different socioeconomic backgrounds (SES). We assessed PA, SB, parental education, and household income using detailed questionnaires in a representative population sample of 486 children (238 girls, 248 boys) aged 6–8 years. Girls spent on average 1.7 h/day and boys 2.0 h/day in total PA (p?=?0.002). Altogether 66% of girls and 54% of boys had less than 2 h of total PA per day (p?=?0.012). Girls had lower levels of unsupervised PA (45 vs. 54 min/day, p?=?0.001), supervised PA (1.5 vs. 1.9 h/week, p?=?0.009), and PA during school recess (1.8 vs. 1.9 h/week, p?=?0.032) than boys. Girls had higher levels of total SB (3.8 vs. 3.4 h/day, p?=?0.015) but lower levels of screen-based SB (1.5 vs. 1.9 h/day, p?<?0.001) than boys. Lower parental education and household income were associated with lower levels of supervised PA in girls (p?=?0.011 and p?=?0.008, respectively) and in boys (p?=?0.006 and p?=?0.003, respectively). Lower parental education and household income were also related to higher levels of screen-based SB in boys (p?=?0.005 and p?<?0.001, respectively) but not in girls. Girls have lower levels of total, unsupervised, and supervised PA, PA during recess, and screen-based SB but higher levels of total SB than boys. Lower parental education and household income are associated with lower levels of supervised PA in both genders and higher levels of screen-based SB in boys.