Scaling the Equipment and Play Area in Children’s Sport to improve Motor Skill Acquisition: A Systematic Review

BACKGROUND: This review investigated the influence of scaling sports equipment and play area (e.g., field size) on children’s motor skill acquisition. METHODS: Peer-reviewed studies published prior to February 2015 were searched using SPORTDiscus and MEDLINE. Studies were included if the research (a) was empirical, (b) involved participants younger than 18 years, (c) assessed the efficacy of scaling in relation to one or more factors affecting skill learning (psychological factors, skill performance and skill acquisition factors, biomechanical factors, cognitive processing factors), and (d) had a sport or movement skills context. Risk of bias was assessed in relation to selection bias, detection bias, attrition bias, reporting bias and other bias. RESULTS: Twenty-five studies involving 989 children were reviewed. Studies revealed that children preferred using scaled equipment over adult equipment (n = 3), were more engaged in the task (n = 1) and had greater self-efficacy to execute skills (n = 2). Eighteen studies demonstrated that children performed skills better when the equipment and play area were scaled. Children also acquired skills faster in such conditions (n = 2); albeit the practice interventions were relatively short. Five studies showed that scaling led to children adopting more desirable movement patterns, and one study associated scaling with implicit motor learning. CONCLUSION: Most of the studies reviewed provide evidence in support of equipment and play area scaling. However, the conclusions are limited by the small number of studies that examined learning (n = 5), poor ecological validity and skills tests of few trials

Justice at the margins: witches, poisoners, and social accountability in Northern Uganda

Recent responses to people alleged to be ‘witches’ or ‘poisoners’ among the Madi of northern Uganda are compared with those of the 1980s. The extreme violence of past incidents is set in the context of contemporary upheavals and, in effect, encouragement from Catholic and governmental attitudes and initiatives. Mob justice has subsequently become less common. From 2006, a democratic system for dealing with suspects was introduced, whereby those receiving the highest number of votes are expelled from the neighborhood or punished in other ways. These developments are assessed with reference to trends in supporting ‘traditional’ approaches to social accountability and social healing as alternatives to more conventional measures. Caution is required. Locally acceptable hybrid systems may emerge, but when things turn nasty, it is usually the weak and vulnerable that suffer

Fast rates in statistical and online learning

The speed with which a learning algorithm converges as it is presented with more data is a central problem in machine learning --- a fast rate of convergence means less data is needed for the same level of performance. The pursuit of fast rates in online and statistical learning has led to the discovery of many conditions in learning theory under which fast learning is possible. We show that most of these conditions are special cases of a single, unifying condition, that comes in two forms: the central condition for 'proper' learning algorithms that always output a hypothesis in the given model, and stochastic mixability for online algorithms that may make predictions outside of the model. We show that under surprisingly weak assumptions both conditions are, in a certain sense, equivalent. The central condition has a re-interpretation in terms of convexity of a set of pseudoprobabilities, linking it to density estimation under misspecification. For bounded losses, we show how the central condition enables a direct proof of fast rates and we prove its equivalence to the Bernstein condition, itself a generalization of the Tsybakov margin condition, both of which have played a central role in obtaining fast rates in statistical learning. Yet, while the Bernstein condition is two-sided, the central condition is one-sided, making it more suitable to deal with unbounded losses. In its stochastic mixability form, our condition generalizes both a stochastic exp-concavity condition identified by Juditsky, Rigollet and Tsybakov and Vovk's notion of mixability. Our unifying conditions thus provide a substantial step towards a characterization of fast rates in statistical learning, similar to how classical mixability characterizes constant regret in the sequential prediction with expert advice setting.Comment: 69 pages, 3 figure

Mormons and evolution : a history of B. H. Roberts and his attempt to reconcile science and religion

Although much has been written describing the various reactions to the origin of Species in America, the Mormon reaction to Darwinism has been largely ignored. This dissertation will recount the history of this reaction as exemplified by the life and works of B. H. Roberts. Roberts's intellectual pursuits early in life reveal a period of Latter-day Saint history when Mormons enjoyed relative intellectual freedom. However, the encroachment of secular knowledge upon the isolation of the Saints resulted in a conservative reaction to secular learning. The LDS response to Roberts's later work, including his own unique theory of evolution, best illustrates the conservative reaction that continues to the present. Roberts's early work is marked by speculation regarding origins and creation. Like many Church leaders who preceded him, Roberts believed that all Latter-day Saints should take full advantage of secular learning in order to best understand the workings of the divine; according to Roberts, science should be a support and supplement to theology. Later in life, the conservative reaction to Roberts's belief in the theory of evolution is illustrative of the changing intellectual climate. In his major theological treatise, The Truth, The Way, The Life, Roberts tries to combine all extant knowledge, including the theory of evolution, into a coherent whole. In April of 1930, Mormon Apostle Joseph Fielding Smith publicly opposed Roberts's evolutionary views in favor of a literal reading of scripture. The public confrontation between Smith and Roberts led to a private debate before the Quorum of the Twelve Apostles. After much deliberation, the Quorum of the Twelve decided that nothing could be gained by further consideration of the matter. Reaffirming a statement issued by the First Presidency of the Church in 1909, they agreed that God had created man; anything beyond this was mere speculation. Roberts died of diabetes one year after the debate and his masterwork remained unpublished until 1994

BayesCG As An Uncertainty Aware Version of CG

The Bayesian Conjugate Gradient method (BayesCG) is a probabilistic generalization of the Conjugate Gradient method (CG) for solving linear systems with real symmetric positive definite coefficient matrices. We present a CG-based implementation of BayesCG with a structure-exploiting prior distribution. The BayesCG output consists of CG iterates and posterior covariances that can be propagated to subsequent computations. The covariances are low-rank and maintained in factored form. This allows easy generation of accurate samples to probe uncertainty in subsequent computations. Numerical experiments confirm the effectiveness of the posteriors and their low-rank approximations.Comment: 31 Pages including supplementary material (main paper is 22 pages, supplement is 9 pages). Computer codes are available at https://github.com/treid5/ProbNumCG_Sup

Attitudes Toward the Practical Incorporation of Scenario Based Training (SBT) into a Commercial Pilot Training Syllabus: A Preliminary Study

As aviation moves into its second century, aircraft accidents still occur, though at a very low rate. With that said, the rate of pilot-related accidents in General Aviation (GA) has not decreased when compared against the rate of mechanical-related accidents in GA. According to the 2010 Nall Report, the number of GA aircraft accidents that were pilot-related made up for 73.9% (857 accidents), mechanical-related accidents made up for 15.0% (174 accidents) and other unknown causes made up for 11.1% (129 accidents) of all accidents that year (Kenny, 2011). According to Kenny (2011), “Most pilot-related accidents reflect specific failures of flight planning or decision-making or the characteristic hazards of high-risk phases of flight.” As pilot-related accident rates continue to be higher than mechanical-related accidents, exploration and experimentation is being conducted to look for new ways to address this issue

Maturation of auditory temporal integration and inhibition assessed with event-related potentials (ERPs)

Background: We examined development of auditory temporal integration and inhibition by assessing electrophysiological responses to tone pairs separated by interstimulus intervals (ISIs) of 25, 50, 100, 200, 400, and 800 ms in 28 children aged 7 to 9 years, and 15 adults.Results: In adults a distinct neural response was elicited to tones presented at ISIs of 25 ms or longer, whereas in children this was only seen in response to tones presented at ISIs above 100 ms. In adults, late N1 amplitude was larger for the second tone of the tone pair when separated by ISIs as short as 100 ms, consistent with the perceptual integration of successive stimuli within the temporal window of integration. In contrast, children showed enhanced negativity only when tone pairs were separated by ISIs of 200 ms. In children, the amplitude of the P1 component was attenuated at ISIs below 200 ms, consistent with a refractory process.Conclusions: These results indicate that adults integrate sequential auditory information into smaller temporal segments than children. These results suggest that there are marked maturational changes from childhood to adulthood in the perceptual processes underpinning the grouping of incoming auditory sensory information, and that electrophysiological measures provide a sensitive, non-invasive method allowing further examination of these changes