Gesture as a window on children's beginning understanding of false belief

Given that gestures may provide access to transitions in cognitive development, preschoolers' performance on standard tasks was compared with their performance on a new gesture false belief task. Experiment 1 confirmed that children (N=45, M age=54 months) responded consistently on two gesture tasks and that there is dramatic improvement on both the gesture false belief task and a standard task from ages 3 to 5. In 2 subsequent experiments focusing on children in transition with respect to understanding false beliefs (Ns=34 and 70, M age=48 months), there was a significant advantage of gesture over standard and novel verbal-response tasks. Iconic gesture may facilitate reasoning about opaque mental states in children who are rapidly developing concepts of mind.     

Nutrition for the young athlete

Athletics is a popular sport among young people. To maintain health and optimize growth and athletic performance, young athletes need to consume an appropriate diet. Unfortunately, the dietary intake of many young athletes follows population trends rather than public health or sports nutrition recommendations. To optimize performance in some disciplines, young athletes may strive to achieve a lower body weight or body fat content and this may increase their risk for delayed growth and maturation, amenorrhoea, reduced bone density, and eating disorders. Although many of the sports nutrition principles identified for adults are similar to those for young athletes, there are some important differences. These include a higher metabolic cost of locomotion and preferential fat oxidation in young athletes during exercise. Young athletes, particularity children, are at a thermoregulatory disadvantage due to a higher surface area to weight ratio, a slower acclimatization, and lower sweating rate. An appropriate dietary intake rather than use of supplements (except when clinically indicated) is recommended to ensure young athletes participate fully and safely in athletics.     

Statistical methods for analysing discrete and categorical data recorded in performance analysis

In this paper, we identify appropriate statistical methods for analysing categorical differences in discrete variables or 'performance indicators' resulting from performance analysis. The random mechanisms associated with discrete events do not follow a normal distribution; that is, the normal distribution is a continuous not a discrete probability distribution. We propose appropriate statistical methods based on two key discrete probability distributions, the Poisson and binomial distributions. Two approaches are proposed and compared using examples from notational analysis. The first approach is based on the classic chi-square test of significance (both the goodness-of-fit test and the test of independence). The second approach adopts a more contemporary method based on log-linear and logit models fitted using the statistical software GLIM. Provided relatively simple one-way and two-way comparisons in categorical data are required, both of these approaches result in very similar conclusions. However, as soon as more complex models or higher-order comparisons are required, the approach based on log-linear and logit models is shown to be more effective. Indeed, when investigating those factors and categorical differences associated with binomial or binary response variables, such as the proportion of winners when attempting decisive shots in squash or the proportion of goals scored from all shots in association football, logit models become the only realistic method available. By applying log-linear and logit models to discrete events resulting from notational analysis, greater insight into the underlying mechanisms associated with sport performance can be achieved.     

Arousal, anxiety, and performance: a reexamination of the Inverted-U hypothesis

Until recently, the traditional Inverted-U hypothesis had been the primary model used by sport psychologists to describe the arousal-performance relationship. However, many sport psychology researchers have challenged this relationship, and the current trend is a shift toward a more "multidimensional" view of arousal-anxiety and its effects on performance. In the current study, 104 college-age participants performed a simple response time task while riding a bicycle ergometer. Participants were randomly assigned to one of eight arousal groups (between 20 and 90% of heart rate reserve) and were told they were competing for a cash prize. Prior to the task, the Competitive State Anxiety Inventory-2 and Sport Anxiety Scale (SAS) were administered to assess the influence of cognitive and somatic anxiety. As hypothesized, regression analysis revealed a significant quadratic trend for arousal and reaction time. This accounted for 13.2% of the variance, F change (1, 101) = 15.10, p < .001, in performance beyond that accounted for by the nonsignificant linear trend. As predicted by the Inverted-U hypothesis, optimal performance on the simple task was seen at 60 and 70% of maximum arousal. Furthermore, for the simple task used in this study, only somatic anxiety as measured by the SAS accounted for significant variance in performance beyond that accounted for by arousal alone. These findings support predictions of the Inverted-U hypothesis and raise doubts about the utility theories that rely on differentiation of cognitive and somatic anxiety to predict performance on simple tasks that are not cognitively loaded.     

CSRP's Impact on low-income preschoolers' preacademic skills: self-regulation as a mediating mechanism

Based on theoretically driven models, the Chicago School Readiness Project (CSRP) targeted low-income children's school readiness through the mediating mechanism of self-regulation. The CSRP is a multicomponent, cluster-randomized efficacy trial implemented in 35 Head Start-funded classrooms (N = 602 children). The analyses confirm that the CSRP improved low-income children's self-regulation skills (as indexed by attention/impulse control and executive function) from fall to spring of the Head Start year. Analyses also suggest significant benefits of CSRP for children's preacademic skills, as measured by vocabulary, letter-naming, and math skills. Partial support was found for improvement in children's self-regulation as a hypothesized mediator for children's gains in academic readiness. Implications for programs and policies that support young children's behavioral health and academic success are discussed.     

Vaginal lacerations from consensual intercourse in adolescents

Objective

(1) To describe lacerations of the vaginal fornices, an injury known to be associated with consensual sexual intercourse, including known complications and treatment course, (2) to contrast these injuries with injuries sustained during sexual assault, and (3) to discuss the assessment of adolescent patients for sexual injuries.

Methods

We present a case series of 4 female adolescent patients seen at a children's hospital over a period of 6 months. Each patient developed significant vaginal bleeding after sexual intercourse, and 3 of the patients presented to the emergency department with vital signs consistent with compensated shock.

Results

Each patient was evaluated by pediatric surgery, and found to have a laceration of the vagina. Three of the patients described consensual intercourse prior to the onset of bleeding, and had lacerations of the vaginal fornices; these patients were determined to have injuries resulting from consensual sexual intercourse. The fourth patient reported sexual assault as the cause of her injuries, and was treated for longitudinal lacerations of the vaginal wall.

Conclusions

Lacerations of the upper vagina are not frequently reported in forced vaginal intercourse, but are occasionally reported as injuries sustained during consensual coitus. In the absence of reported sexual assault, a severe vaginal fornix laceration is consistent with the diagnosis of coital injury from consensual intercourse. Diagnosis and treatment of this injury can be delayed due to the sensitive nature of these injuries. Bleeding can be profuse, leading to hemorrhagic shock, and these injuries may require transfusion of blood products and surgical repair in some cases. Complications may include hemoperitoneum, pneumoperitoneum, or retroperitoneal hematoma, even in the absence of complete vaginal perforation.

Practice implications

Knowledge of the consensual sexual injuries that may occur in adolescent patients can guide diagnosis, treatment, and counseling for the patient and her family, preventing long-term medical complications and legal consequences.     

An analysis of the relationship between the linear hammer speed and the thrower applied forces during the hammer throw for male and female throwers

The purpose of this study was to investigate the relationship between the cable force and linear hammer speed in the hammer throw and to identify how the magnitude and direction of the cable force affects the fluctuations in linear hammer speed. Five male (height: 1.88 +/- 0.06 m; body mass: 106.23 +/- 4.83 kg) and five female (height: 1.69 +/- 0.05 m; body mass: 101.60 +/- 20.92 kg) throwers participated and were required to perform 10 throws each. The hammer's linear velocity and the cable force and its tangential component were calculated via hammer head positional data. As expected, a strong correlation was observed between decreases in the linear hammer speed and decreases in the cable force (normalised for hammer weight). A strong correlation was also found to exist between the angle by which the cable force lags the radius of rotation at its maximum (when tangential force is at its most negative) and the size of the decreases in hammer speed. These findings indicate that the most effective way to minimise the effect of the negative tangential force is to reduce the size of the lag angle.