Changes in kinematics and arm–leg coordination during a 100-m breaststroke swim

The purpose of this study was to compare arm–leg coordination and kinematics during 100 m breaststroke in 26 (8 female; 18 male) specialist breaststroke swimmers. Laps were recorded using three 50-Hz underwater cameras. Heart rate and blood lactate were measured pre- and post-swim. Arm–leg coordination was defined using coordination phases describing continuity between recovery and propulsive phases of upper and lower limbs: coordination phase 1 (time between end of leg kick and start of the arm pull phases); and coordination phase 2 (time between end of arm pull and start of leg kick phases). Duration of stroke phases, coordination phases, swim velocity, stroke length (SL), stroke rate (SR) and stroke index (SI) were analysed during the last three strokes of each lap that were unaffected by turning or finishing. Significant changes in velocity, SI and SL (P < 0.05) were found between laps. Both sexes showed significant increase (P < 0.05) in heart rate and blood lactate pre- to post-swim. Males had significantly (P < 0.01) faster swim velocities resulting from longer SLs (P = 0.016) with no difference in SR (P = 0.064). Sex differences in kinematic parameters can be explained by anthropometric differences providing males with increased propelling efficiency.     

30 min of treadmill walking at self-selected speed does not increase gait variability in independent elderly

Walking is one of the preferred exercises among elderly, but could a prolonged walking increase gait variability, a risk factor for a fall in the elderly? Here we determine whether 30 min of treadmill walking increases coefficient of variation of gait in elderly. Because gait responses to exercise depend on fitness level, we included 15 sedentary and 15 active elderly. Sedentary participants preferred a lower gait speed and made smaller steps than the actives. Step length coefficient of variation decreased ~16.9% by the end of the exercise in both the groups. Stride length coefficient of variation decreased ~9% after 10 minutes of walking, and sedentary elderly showed a slightly larger step width coefficient of variation (~2%) at 10 min than active elderly. Active elderly showed higher walk ratio (step length/cadence) than sedentary in all times of walking, but the times did not differ in both the groups. In conclusion, treadmill gait kinematics differ between sedentary and active elderly, but changes over time are similar in sedentary and active elderly. As a practical implication, 30 min of walking might be a good strategy of exercise for elderly, independently of the fitness level, because it did not increase variability in step and stride kinematics, which is considered a risk of fall in this population.     

The Invisible Scholar: Authors of Legal Scholarship in Criminology and Criminal Justice Journals

This study assesses the authorship of legal scholarship within 20 criminology and criminal justice (CCJ) journals from 2005 to 2015, examining trends over time and variation across journals in the prevalence of sole-authorship and the mean number of authors and identifying the most prolific authors of legal scholarship published in CCJ journals. The study thus sheds light on the extent of collaboration among CCJ legal scholars and identifies CCJ legal scholars who have remained largely invisible due to their focus on a marginalized subfield.     

Infant Pathways to Externalizing Behavior: Evidence of Genotype × Environment Interaction

To further the understanding of the effects of early experiences, 9-month-old infants were observed during a frustration task. The analytical sample was composed of 348 linked triads of participants (adoptive parents, adopted child, and birth parent[s]) from a prospective adoption study. It was hypothesized that genetic risk for externalizing problems and affect dysregulation in the adoptive parents would independently and interactively predict a known precursor to externalizing problems: heightened infant attention to frustrating events. Results supported the moderation hypotheses involving adoptive mother affect dysregulation: Infants at genetic risk showed heightened attention to frustrating events only when the adoptive mother had higher levels of anxious and depressive symptoms. The Genotype × Environment interaction pattern held when substance use during pregnancy was considered.     

Software to Promote Young Children’s Growth in Literacy: A Comparison of Online and Offline Formats

The primary goal of this research was to extend our understanding of the strengths and weaknesses inherent in online and offline early literacy software programs designed for young learners. A taxonomy of reading skills was used to contrast online software with offline closed system (compact disc) based programs with respect to number of skills taught, quality of instruction and scaffolding during instruction. Overall, online programs were more comprehensive and provided instruction for more skills than offline software at either the Kindergarten or Grade 1 level. However, offline programs demonstrated some developmentally appropriate selectivity in skills trained. Quality of instruction was variable within and across all programs. Scaffolding of instruction was also variable and surprisingly few programs, either online or offline, provided automatic movement across levels of difficulty. These outcomes have important implications for the selection of instructional materials by parents and educators involved in early literacy instruction and also for future software design.     

Chemistry at the Nanoscale

Traditionally the kinetics of a chemical reaction has been studied as a set of coupled ordinary differential equations. The law of mass action, a tried and tested principle for reactions involving macroscopic quantities of reactants, gives rise to deterministic equations in which the variables are species concentrations. In recent years, though, as smaller and smaller systems – such as an individual biological cell, say – can be studied quantitatively, the importance of molecular discreteness in chemical reactions has increasingly been realized. This is particularly true when the system is far from the ‘thermodynamic limit’ when the numbers of all reacting molecular species involved are several orders of magnitude smaller than Avogadro’s number. In such situations, each reaction has to be treated as a probabilistic ‘event’ that occurs by chance when the appropriate reactants collide. Explicitly accounting for such processes has led to the development of sophisticated statistical methods for simulation of chemical reactions, particularly those occurring at the cellular and sub-cellular level. In this article, we describe this approach, the so-called stochastic simulation algorithm, and discuss applications to study the dynamics of model regulatory networks.     

A static method for obtaining a calibration factor for SRM bicycle power cranks

Many scientists and coaches are interested in mechanical power produced during cycling, and use Schoberer Rad Me\technik (SRM) bicycle power cranks to obtain this data. However, it has been expensive and difficult to calibrate SRM cranks, causing much of the collected data to be unreliable. We present a static method, derived from first principles, for obtaining a calibration factor for SRM cranks. A known mass and lever arm (chainring of a known diameter) are used to apply a known torque load to the instrument in four positions, and the output frequencies are used to calculate the calibration factor in Hz/Nm. The reproducibility of this method is ±0.01 Hz/Nm, which is acceptable for the application of the instrument, which is measurement of mechanical power application by cyclists at the crank. The method is reliable, inexpensive, and easy to set up, and will allow higher confidence in data collected using SRM power cranks. We recommend calibration of the power meter once every six months because of the measured drift of the calibration factor over time.     

Analyzing the temporal evolution of students’ behaviors in open-ended learning environments

Metacognition and self-regulation are important for developing effective learning in the classroom and beyond, but novice learners often lack effective metacognitive and self-regulatory skills. However, researchers have demonstrated that metacognitive processes can be developed through practice and appropriate scaffolding. Betty’s Brain, an open-ended computer-based learning environment, helps students practice their cognitive skills and develop related metacognitive strategies as they learn science topics. In this paper, we analyze students’ activity sequences in a study that compared different categories of adaptive scaffolding in Betty’s Brain. The analysis techniques for measuring students’ cognitive and metacognitive processes extend our previous work on using sequence mining methods to discover students’ frequently-used behavior patterns by (i) developing a systematic approach for interpreting derived behavior patterns using a cognitive/metacognitive task model and (ii) analyzing the evolution of students’ frequent behavior patterns over time. Our results show that it is possible to identify students’ learning behaviors and analyze their evolution as they work in the Betty’s Brain environment. Further, the results illustrate that changes in student behavior were generally consistent with the scaffolding provided, suggesting that these metacognitive strategies can be taught to middle school students in computer-based learning environments.     

What factors motivate male and female Generation Z students to become engaged as peer teachers? A mixed-method study among medical and dental students in the gross anatomy course

Peer-teaching is widely established in anatomy teaching and offers well-described advantages. Nevertheless, at Ulm University, Germany, a reduction in the number of peer teacher applicants for the dissection course was observed. This study examined factors related to the attractiveness of a position as a peer teacher for Generation Z students. Participants of the gross anatomy course were asked to evaluate factors influencing the attractiveness of a peer teacher position using a six-point Likert scale. Additionally, open-ended questions were analyzed qualitatively. Sex-specific subgroup analysis was performed comparing students of low and high motivation to apply for a tutorship. Of the 374 students who participated in this study (response rate 53%), 38% stated that they were intending to apply as peer teachers. Data indicated that students displayed intrinsic motivation to apply for a tutorship because of the opportunity to improve their anatomy knowledge and/or their pleasure in teaching. In contrast, extrinsic factors like remuneration of the tutorship and its relevance for their curriculum vitae were least important. Anatomy educators underestimated the demotivating factor of the workload associated with the tutorship and encouraged students less frequently to apply than peer teachers. Only minor sex-specific differences could be identified. Nevertheless, female students were encouraged less frequently to apply than their male peers. In summary, Generation Z students apply as peer teachers because they are enthusiastic about the task. To motivate students to commit to extracurricular activities like a tutorship, anatomy educators should actively encourage students—particularly females—more frequently to apply.