1,890 research outputs found
Scaling the Equipment and Play Area in Childrenâs 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 childrenâs 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 âwitchesâ or âpoisonersâ 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 âtraditionalâ 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
Assessing multiple threats to seabird populations using flesh-footed shearwaters Ardenna carneipes on Lord Howe Island, Australia as case study
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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
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A second look at Alexander Pope and Newtonian science
"This Long Disease, My Life": Alexander Pope and the
Sciences by Marjorie Nicolson and G.S. Rousseau has been the
standard work on Alexander Pope and Newtonian science ever
since it was published in 1968. Literary scholars and
biographers continue to be swayed by its influence.
Unfortunately, the work they so often rely upon is in need
of some revision.
The literary evidence offered by Nicolson and Rousseau
suggests that Pope was a staunch Newtonian. However, this
is an exaggeration. They also claim that his scientific
references were almost exclusively Newtonian. Once again,
this is not entirely correct.
The evidence contained in this thesis attempts to amend
the inaccuracies in their work. It suggests that Pope was
not as staunch a Newtonian as was formerly believed. Other
philosophies influenced Pope's work almost as much as
Newtonian science. Pope also participated in scientific
satire and voiced some reservations against the new science.
This evidence suggests that Pope was a transitional
figure. He lived in a world where Newton and his science
were beginning to be appreciated; however, many other
philosophies continued to be influential and Newton had not
yet become the cultural icon that he would later become in
the late-eighteenth century. A second look at Alexander
Pope and the sciences reveals the actual nature of the
period in which he lived.
In order to prove this thesis, the first chapter begins
by defining the problem. The next two chapters then create
a solid foundation upon which the rest of this work is
based. Chapter Two discusses the enigmatic nature of
Newton's philosophy and the different versions of Newtonian
science that emerged as a result. Chapter Three attempts to
define a consistent version of Newtonian science. Once
defined, this version will be used as the standard
throughout the work. Chapter Four will present the evidence
that suggests that the literary works of Alexander Pope were
influenced by this version of Newtonian science. Chapter
Five will exhibit evidence that suggests that other
philosophies in general and the work of Bernard Fontenelle
in particular also influenced the work of Alexander Pope.
Chapter Six will give a short history of the Scriblerus Club
and explain how Pope sanctioned the scientific satire of its
members. This approach will reveal a man who was influenced
by many different ideas and had many different facets to his
complex personality
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), âMost pilot-related accidents reflect specific failures of flight planning or decision-making or the characteristic hazards of high-risk phases of flight.â 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
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