Submovement Organization,Pen Pressure,and Muscle Activity Are Modulated to Precision Demands in 2D Tracking

The authors investigated how tracking performance, submovement organization, pen pressure and muscle activity in forearm and shoulder muscles were affected by target size in a 2D tracking task performed with a pen on a digitizer tablet. Twenty-six subjects took part in an experiment, in which either a small dot or a large dot was tracked, while it moved quasirandomly across a computer screen at a constant velocity of 2 cm/s. The manipulation of precision level was successful, because mean distance to target and the standard deviation of this distance were significantly smaller with the small target than with the large target. With a small target, subjects trailed more behind the center of target and used submovements with larger amplitudes and of shorter duration, resulting in higher tracking accuracy. This change in submovement organization was accompanied by higher pen pressure, while at the same time muscle activity in the forearm extensors and flexors was increased, indicating higher endpoint stability. In conclusion, increased precision demands were accommodated by both a different organization of submovements and higher endpoint stability in a 2D tracking task performed with a pen on a digitizer tablet.     

Gaining the Upper Hand: Evidence of Vertical Asymmetry in Sex-Categorisation of Human Hands

Visual perception is characterised by asymmetries arising from the brain’s preferential response to particular stimulus types at different retinal locations. Where the lower visual field (LVF) holds an advantage over the upper visual field (UVF) for many tasks (e.g., hue discrimination, contrast sensitivity, motion processing), face-perception appears best supported at above-fixation locations (Quek & Finkbeiner, 2014a). This finding is consistent with Previc’s (1990) suggestion that vision in the UVF has become specialised for object recognition processes often required in ”extrapersonal” space. Outside of faces, however, there have been very few investigations of vertical asymmetry effects for higher-level objects. Our aim in the present study was, thus, to determine whether the UVF advantage reported for face-perception would extend to a nonface object – human hands. Participants classified the sex of hand images presented above or below central fixation by reaching out to touch a left or right response panel. On each trial, a briefly presented spatial cue captured the participant’s spatial attention to either the location where the hand was about to appear (valid cue) or the opposite location (invalid cue). We observed that cue validity only modulated the efficiency of the sex-categorisation response for targets in the LVLVF and not the UVF, just as we have reported previously for face-sex categorisation (Quek & Finkbeiner, 2014a). Taken together, the data from these studies provide some empirical support for Previc’s (1990) speculation that object recognition processes may enjoy an advantage in the upper-hemifield.     

Personality traits measured at baseline can predict academic performance in upper secondary school three years late

The aim of the present study was to explore the ability of personality to predict academic performance in a longitudinal study of a Swedish upper secondary school sample. Academic performance was assessed throughout a three‐year period via final grades from the compulsory school and upper secondary school. The Big Five personality factors (Costa & McCrae, 1992 ) – particularly Conscientiousness and Neuroticism – were found to predict overall academic performance, after controlling for general intelligence. Results suggest that Conscientiousness, as measured at the age of 16, can explain change in academic performance at the age of 19. The effect of Neuroticism on Conscientiousness indicates that, as regarding getting good grades, it is better to be a bit neurotic than to be stable. The study extends previous work by assessing the relationship between the Big Five and academic performance over a three‐year period. The results offer educators avenues for improving educational achievement.     

腔内成形术治疗下肢动脉硬化闭塞症的技巧及临床观察

评价腔内成形术（PTA及PTAS）治疗下肢动脉硬化闭塞症的技巧和临床观察。2010年10月至2013年10月,对37例下肢动脉硬化闭塞症血管多段病变患者采用经皮血管腔内成形术和经皮血管腔内成形＋支架植入术治疗。结果36（97％）例手术成功,术后肢体缺血症状完全消失或明显改善,38条患肢皮温明显升高,间歇性跛行消失或距离延长,静息痛好转。术后踝／肱指数（ABI）（0．83±0．12）与术前（0．35±0．07）比较差异有统计学意义（P〈0．05）。合理的腔内成形术（PTA＋PTAS）是治疗下肢动脉硬化闭塞症安全有效的方法。熟练掌握腔内成形术是提高手术成功率和维持通畅率的关键。     

A Fully Automated,Quantitative Test of Upper Limb Function

ABSTRACT. The Rehabilitation Joystick for Computerized Exercise (ReJoyce, Rehabtronics Inc., Edmonton, Alberta, Canada), is a workstation on which participants exercise dexterous movement tasks in the guise of computer games. The system incorporates the ReJoyce Arm and Hand Function Test (RAHFT). Here the authors evaluate the RAHFT against the Action Research Arm Test (ARAT) and the Fugl-Meyer Assessment (FMA). All 3 tests were performed in 36 separate sessions in 13 tetraplegic individuals. Concurrent and criterion validities of the RAHFT were supported by a high level of correlation with the ARAT (r² = .88). Regarding responsiveness, the effect size of the RAHFT at week 6 of 1 hr/day exercise training was 1.8. Regarding reliability, the mean test–retest difference in RAHFT baseline scores was 0.67% ± 3.6%, which was not statistically significant. The RAHFT showed less ceiling effect than either ARAT or FMA. These data help validate the RAHFT as a quantitative, automated alternative to the ARAT and FMA. The RAHFT is the first comprehensive test of arm and dexterous hand function that does not depend on human judgment. It offers a standardized, quantitative outcome evaluation, which can be performed not only in the clinic, but also in the participant's home, administered by a remote therapist over the Internet.     

Organizational Tenure Diversity as Predictors of Combat Performance in ROK Army

Drawing on the upper-echelons theory and diversity issues, this study examines the relationships between top management team (TMT) organizational tenure, tenure diversity, and combat performance. The study is based on of Korea Combat Training Center (KCTC) that is designed for training and evaluation of the battalion combat power. Findings indicate that battalions with higher levels of TMT tenure have a positive effect on combat performance. Tenure diversity of TMT has a negative effect on combat performance. In addition, results showed that the negative relationships between tenure diversity of TMT and combat performance are attenuated by commander’s shared experience with other TMT members.     

The effect of running speed on joint coupling coordination and its variability in recreational runners

The purpose of this study was to examine the effect of speed on coordination and its variability in running gait using vector coding analysis. Lower extremity kinematic data were collected for thirteen recreational runners while running at three different speeds in random order: preferred speed, 15% faster and 15% lower than preferred speed. A dynamical systems approach, using vector coding and circular statistics, were used to quantify coordination and its variability for selected hip-knee and knee-ankle joint couplings. The influence of running speed was calculated from the continuous data sets of the running cycle, allowing for the identification of time percentages where differences existed. Results indicate that increases in running speed produced moderate alterations in the frequency of movement patterns which were not enough to alter classification of coordination. No effects of speed on coordination variability were observed. This study has demonstrated that coordination and coordination variability is generally stable in the range of ±15% around of preferred speed in recreational runners.     

Anticipating ankle inversion perturbations during a single-leg drop landing alters ankle joint and impact kinetics

Anticipatory responses to inversion perturbations can prevent an accurate assessment of lateral ankle sprain mechanics when using injury simulations. Despite recent evidence of the anticipatory motor control strategies utilized during inversion perturbations, kinetic compensations during anticipated inversion perturbations are currently unknown. The purpose of this investigation was to examine the influence of anticipation to an inversion perturbation during a single-leg drop landing on ankle joint and impact kinetics. Fifteen young adults with no lateral ankle sprain history completed unanticipated and anticipated single-leg drop landings onto a 25° laterally inclined platform from a height of 30 cm. One-dimensional statistical parametric mapping (SPM) was used to analyze net ankle moments and ground reaction forces (GRF) during the first 150 ms post-landing, while peak GRFs, time to peak GRF, peak and average loading rates were compared using a dependent samples t-test (p ≤ 0.05). Results from the SPM analysis revealed significantly greater plantar flexion moment from 58 to 83 ms post-landing (p = 0.004; d = 0.64–0.77), inversion moment from 89 to 91 ms post-landing (p = 0.050; d = 0.58–0.60), and medial GRF from 62 to 97 ms post-landing (p < 0.001; d = 1.00–2.39) during the unanticipated landing condition. Moreover, significantly greater peak plantarflexion (p < 0.001; d = 1.10) and peak inversion moment (p = 0.007; d = 0.94), as well as greater peak (p = 0.002; d = 1.03) and average (p = 0.042; d = 0.66) medial loading rates, were found during the unanticipated landing condition. Our findings suggest alterations to ankle joint and impact kinetics occur during a single-leg drop landing when inversion perturbations are anticipated. Researchers and practitioners using drop-landings onto a tilted surface to assess lateral ankle sprain injury risk should consider implementing protocols that mitigate anticipatory responses.     

Understanding ‘Unlikely (20% Likelihood)’ or ‘20% Likelihood (Unlikely)’ Outcomes: The Robustness of the Extremity Effect

Calls to communicate uncertainty using mixed, verbal‐numerical formats (‘unlikely [0–33%]’) have stemmed from research comparing mixed with solely verbal communications. Research using the new ‘which outcome’ approach to investigate understanding of verbal probability expressions suggests, however, that mixed formats might convey disadvantages compared with purely numerical communications. When asked to indicate an outcome that is ‘unlikely’, participants have been shown to often indicate outcomes with a value exceeding the maximum value shown, equivalent to a 0% probability —an ‘extremity effect’. Recognising the potential consequences of communication recipients expecting an ‘unlikely’ event to never occur, we extend the ‘which outcome’ work across four experiments, using verbal, numerical, and verbal‐numerical communication formats, as well as a previously unconsidered numerical‐verbal format. We examine how robust the effect is in the context of consequential outcomes and over non‐normal distributions. We also investigate whether participants are aware of the inconsistency in their responses from a traditional ‘how likely’ and ‘which outcome’ task. We replicate and extend previous findings, with preference for extreme outcomes (including above maximum values) observed in both verbal and verbal‐numerical formats. Our results suggest caution in blanket usage of recently recommended verbal‐numerical formats for the communication of uncertainty. Copyright © 2018 John Wiley & Sons, Ltd.