The dynamics of the impact and coalescence of droplets on a solid surface

A simple experimental setup to study the impact and coalescence of deposited droplets is described. Droplet impact and coalescence have been investigated by high-speed particle image velocimetry. Velocity fields near the liquid-substrate interface have been observed for the impact and coalescence of 2.4 mm diameter droplets of glycerol∕water striking a flat transparent substrate in air. The experimental arrangement images the internal flow in the droplets from below the substrate with a high-speed camera and continuous laser illumination. Experimental results are in the form of digital images that are processed by particle image velocimetry and image processing algorithms to obtain velocity fields, droplet geometries, and contact line positions. Experimental results are compared with numerical simulations by the lattice Boltzmann method.     

Autonomy-connectedness, acculturation, and independence-interdependence among various cultural groups in a multicultural society

The present study was aimed at investigating the relationships between autonomy-connectedness and adherence to independent and interdependent values in second-generation Dutch immigrant women with a background in countries labeled as collectivistic, and same-aged indigenous Dutch women (N = 180 and N = 157, respectively). Both groups completed the Autonomy-Connectedness Scale (ACS-30; Bekker & Van Assen, 2006) and the Self-Construal Scale (Singelis, 1994). Additionally, those with an immigrant background filled out the Acculturation Questionnaire (Arends-Tóth & Van de Vijver, 2003). Contrary to expectations, both groups had similar levels of self-awareness, whereas the indigenous Dutch women were - after controlling for educational level - more sensitive to others. In both groups, but even more in the group with an immigrant background, adherence to independent values appeared to contribute substantially and positively to self-awareness as well as capacity for managing new situations, and negatively to sensitivity to others. In addition, adherence to interdependent values contributed, for both groups, positively to sensitivity to others, and, for those with an immigrant background, negatively to self-awareness. The ACS-30 appeared to be useful for assessing autonomy-connectedness in the immigrant groups that participated in the study. The results confirm that a simple distinction between native and immigrant Dutch groups in terms of being self- or other-focused should be rejected, and give rise to further, clinically relevant research questions.     

Survey results of the training, nutrition, and mental preparation of triathletes: practical implications of findings

Although triathlon is growing in popularity at a remarkable rate, it has not been extensively studied. The aims of this research were to identify preparation strategies used by triathletes and to categorize these strategies according to gender and consultation with triathlon coaches. Survey data collected from 401 triathletes (207 males, 194 females) revealed training, nutritional, and mental preparation habits. Most participants engaged in strength training, consumed food and/or fluids during and after training, set training and competition goals, and applied mental preparation strategies during training and the hour before racing. Water was the most commonly consumed fluid; positive self-talk was the most used mental strategy. Participants were more likely to consult with a triathlon coach than a nutrition or sport psychology professional. Athletes with more years of experience in triathlon and those competing in longer distances were more likely to consult a triathlon coach. Female triathletes were more likely than male triathletes to train with others, use mental preparation strategies, and report feeling anxious before competitions. More male triathletes reported using nutritional supplements during training than their female counterparts. These findings add to the limited research base on triathletes' training habits, and hopefully will help guide practitioners who work with this group. The results provide guidance for collaborative efforts among training, nutrition, and mental health professionals to best support triathletes.     

Home advantage in professional tennis

Home advantage is a pervasive phenomenon in sport. It has been established in team sports such as basketball, baseball, American football, and European soccer. Attention to home advantage in individual sports has so far been limited. The aim of this study was to examine home advantage in professional tennis. Match-level data are used to measure home advantage. The test used is based on logit models, and consistent specification is addressed explicitly. Depending on the interpretation of home advantage, restrictions on the specification of the model need to be imposed. We find that although significant home advantage exists for men, the performance of women tennis players appears to be unaffected by home advantage.     

Effect of hand paddles and parachute on the index of coordination of competitive crawl-strokers

We investigated the effects of hand paddles and parachute on the relative duration of stroke phases and index of coordination of competitive crawl-strokers. Eleven male-swimmers (age: 21.9 ± 4.5 years; 50-m best time: 24.23 ± 0.75 s) were evaluated in four maximal-intensity conditions: without equipment, with hand paddles, with parachute, and with both hand paddles and parachute. Relative stroke phase duration of each arm, swimming velocity, and stroke rate were analysed from video (60 Hz). The index of coordination was quantified based on the lag time between propulsive phases of each arm, which defined the coordination mode as catch-up, opposition or superposition. The stroke rate decreased in all conditions (P < 0.05) and swimming velocity decreased with parachute and with paddles + parachutes (P < 0.05). The coordination mode changed from catch-up in free swimming (-2.3 ± 5.0%) to opposition with paddles (-0.2 ± 3.8%), parachute (0.1 ± 3.1%), and paddles + parachute (0.0 ± 3.2%). Despite these variations, no significant differences were observed in relative duration of right and left arm-stroke phases, or in index of coordination. We conclude that the external resistances analysed do not significantly influence stroke phase organization, but, as a chronic effect, may lead to greater propulsive continuity.     

Perception and action in golf putting: skill differences reflect calibration

We assessed how golfers cope with the commonly observed systematic overshoot errors in the perception of the direction between the ball and the hole. Experiments 1 and 2, in which participants were required to rotate a pointer such that it pointed to the center of the hole, showed that errors in perceived direction (in degrees of deviation from the perfect aiming line) are destroyed when the head is constrained to move within a plane perpendicular to the green. Experiment 3 compared the errors in perceived direction and putting errors of novice and skilled players. Unlike the perceived direction, putting accuracy (in degrees of deviation from the perfect aiming line) was not affected by head position. Novices did show a rightward putting error, while skilled players did not. We argue that the skill-related differences in putting accuracy reflect a process of recalibration. Implications for aiming in golf are discussed.     

体验式教学法在大学生心理健康教育课中的应用探讨

开设大学生心理健康课程已成为大学生心理健康教育的一项有力举措。尝试把体验式教学法运用到大学生心理健康教育课上,是鼓励学生在特定的情境中学会自我反思、自我辩论、自我体验及自我成长。探讨体验式教学法的理论依据及模式构建,从教学内容、课堂教学组织与教学效果评价三个方面论述大学生心理教育课程的教学模式。     

Impact of gender and prior knowledge on learning performance and motivation in a digital game-based learning biology course

Educational technology research and development - Gender and prior knowledge may affect students' performance and motivation when simulations and games are used for learning. Accommodations...