The contribution of skate blade properties to skating speed

The purpose of the study was to investigate the relative contribution of skate blade properties to on-ice skating speed. Thirty-two male ice hockey players (mean age = 19±2.65 yrs.) representing the Ontario Minor Hockey Association (OMHA; Midget AAA and Junior), Canadian Inter University Sport (CIS: Varsity), Ontario hockey league (OHL) and East Coast Hockey League (ECHL), and the playing positions of forwards (n=18) and defense (n=14) were recruited to participate. Skate related equipment worn by the players for the purpose of the research was documented and revealed that 80% of the players wore Bauer skates, Tuuk blade holders and LS2 skate blades. Subjects completed a battery of eight on-ice skating drills used to measure and compare two aspects of skating speed; acceleration [T1(s)] and total time to complete each drill [TT(s)] while skating on three skate blade conditions. The drills represented skills used in the game of hockey, both in isolation (e.g., forward skating, backward skating, stops and starts, and cornering) and in sequence to simulate the combination of skills used in a shift of game play. The three blade conditions consisted of (i) baseline, represented by the blades worn by the player throughout their current season of play; (ii) experimental blades (EB), represented by brand name experimental blades with manufacturers radius of contour and a standardized radius of hollow; and (iii) customized experimental blades (CEB), represented by the same brand name experimental blades sharpened to the players’ preference as identified in the baseline condition. No significant differences were found in acceleration time [T1(s)] or total time to complete [TT(s)] the isolated drills across blade conditions; however significant differences were revealed in both T1(s) and TT(s) measured during the execution of the sequenced drill across blade conditions. A iii Bonferroni post hoc test revealed that players skated significantly faster when skating on the CEB condition compared to the baseline condition (p≤.05). A questionnaire assessing subjects perceived comfort, confidence and effort expended while skating on the experimental blades revealed that players were significantly more comfortable when skating on the CEB versus the EB condition (p≤.05). Outcomes of the study provide evidence to suggest that the experimental skate blades customized with the players preferred blade sharpening characteristics results in faster skating speed in a combination drill representing skills performed in gameplay.

On the Effects of Mergers on Equilibrium Outcomes in a Common Property Renewable Asset Oligopoly

This paper examines a dynamic game of exploitation of a common pool of some renewable asset by agents that sell the result of their exploitation on an oligopolistic market. A Markov Perfect Nash Equilibrium of the game is used to analyze the effects of a merger of a subset of the agents. We study the impact of the merger on the equilibrium production strategies, on the steady states, and on the profitability of the merger for its members. We show that there exists an interval of the asset's stock such that any merger is profitable if the stock at the time the merger is formed falls within that interval. That includes mergers that are known to be unprofitable in the corresponding static equilibrium framework.

Motivation, the Engine of Learning

This essay centers in motivation as a fundamental aspect of learning and in the double way sense that this relation must have. It defines the word “motivation” and the manner how relationship between students and teachers come about in the game of helping out or reduce motivation, and thus learning. It also defines the reason why teachers must help build up the so called “intrinsic motivation”, ending with the importance this has and how it can be achieved.

Performance and prediction: Bayesian modelling of fallible choice in chess

Evaluating agents in decision-making applications requires assessing their skill and predicting their behaviour. Both are well developed in Poker-like situations, but less so in more complex game and model domains. This paper addresses both tasks by using Bayesian inference in a benchmark space of reference agents. The concepts are explained and demonstrated using the game of chess but the model applies generically to any domain with quantifiable options and fallible choice. Demonstration applications address questions frequently asked by the chess community regarding the stability of the rating scale, the comparison of players of different eras and/or leagues, and controversial incidents possibly involving fraud. The last include alleged under-performance, fabrication of tournament results, and clandestine use of computer advice during competition. Beyond the model world of games, the aim is to improve fallible human performance in complex, high-value tasks.

Role playing game eletrônico: uma tecnologia lúdica para aprender e ensinar matemática

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A Construção de identidades online por meio do Role Playing Game: relações com o ensino e aprendizagem de matemática em curso à distância

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Autonomic stress responses elicited by watching a live broadcast soccer game: a pilot study

Aim: Increased rates of hospitalization due to cardiovascular events have been reported during phases of World Soccer Championships (WSC). The purpose of this pilot study was to explore acute psychological and physiological effects of watching a live broadcast soccer game during the WSC 2006. Methods: Seven male supporters (age: M=24; SD=2.7) of the Swiss National Soccer Team watched a game of their team in a controlled laboratory setting. Heart rate (HR), heart rate variability (HRV), salivary cortisol, alpha-amylase (sAA), and testosterone concentrations, as well as several mood ratings were captured repeatedly before, during, and after the game. Results: Subjects reported feeling stressed, and HR and sAA activity showed an increase during the game. In contrast, HRV, cortisol and testosterone were unaffected. Conclusion: Watching a sports competition seems to specifically affect the sympathetic nervous system, which can be measured by sensitive electrocardiographic and salivary markers.

Effects of anxiety on decision making and visual search behaviour in complex sport situations

Introduction Current empirical findings indicate that the efficiency of decision making (both for experts and near-experts) in simple situations is reduced under increased stress (Wilson, 2008). Explaining the phenomenon, the Attentional Control Theory (ACT, Eysenck et al., 2007) postulates an impairment of attentional processes resulting in a less efficient processing of visual information. From a practitioner’s perspective, it would be highly relevant to know whether this phenomenon can also be found in complex sport situations like in the game of football. Consequently, in the present study, decision making of football players was examined under regular vs. increased anxiety conditions. Methods 22 participants (11 experts and 11 near-experts) viewed 24 complex football situations (counterbalanced) in two anxiety conditions from the perspective of the last defender. They had to decide as fast and accurate as possible on the next action of the player in possession (options: shot on goal, dribble or pass to a designated team member) for equal numbers of trials in a near and far distance condition (based on the position of the player in possession). Anxiety was manipulated via a competitive environment, false feedback as well as ego threats. Decision time and accuracy, gaze behaviour (e.g., fixation duration on different locations) as well as state anxiety and mental effort were used as dependent variables and analysed with 2 (expertise) x 2 (distance) x 2 (anxiety) ANOVAs with repeated measures on the last two factors. Besides expertise differences, it was hypothesised that, based on ACT, increased anxiety reduces performance efficiency and impairs gaze behaviour. Results and Discussion Anxiety was manipulated successfully, indicated by higher ratings of state anxiety, F(1, 20) = 13.13, p < .01, ηp2 = .40. Besides expertise differences in decision making – experts responded faster, F(1, 20) = 11.32, p < .01, ηp2 = .36, and more accurate, F(1,20) = 23.93, p < .01, ηp2 = .55, than near-experts – decision time, F(1, 20) = 9.29, p < .01, ηp2 = .32, and mental effort, F(1, 20) = 7.33, p = .01, ηp2 = .27, increased for both groups in the high anxiety condition. This result confirms the ACT assumption that processing efficiency is reduced when being anxious. Replicating earlier findings, a significant expertise by distance interaction could be observed, F(1, 18) = 18.53, p < .01, ηp2 = .51), with experts fixating longer on the player in possession or the ball in the near distance and longer on other opponents, teammates and free space in the far distance condition. This shows that experts are able to adjust their gaze behaviour to affordances of displayed playing patterns. Additionally, a three way interaction was found, F(1, 18) = 7.37 p = .01, ηp2 = .29, revealing that experts utilised a reduced number of fixations in the far distance condition when being anxious indicating a reduced ability to pick up visual information. Since especially the visual search behaviour of experts was impaired, the ACT prediction that particularly top-down processes are affected by anxiety could be confirmed. Taken together, the results show that sports performance is negatively influenced by anxiety since longer response times, higher mental effort and inefficient visual search behaviour were observed. From a practitioner’s perspective, this finding might suggest preferring (implicit) perceptual cognitive training; however, this recommendation needs to be empirically supported in intervention studies. References: Eysenck, M. W., Derakshan, N., Santos, R., & Calvo, M. G. (2007). Anxiety and cognitive performance: Attentional control theory. Emotion, 7, 336-353. Wilson, M. (2008). From processing efficiency to attentional control: A mechanistic account of the anxiety-performance relationship. Int. Review of Sport and Exercise Psychology, 1, 184-201.

From the heart of Israel : Jewish tales and types

by Bernard Drachman. Illustr. by A. Warshawsky

Towards a new concept of leadership

In the present work we have posited some necessary guidelines to reformulate an essential pillar of leadership: the relationship group-leader. The set of enunciations that are developed are meant to establish the basic principles of the theoretical interpretation of this essential phenomenon of social life. In most works dealing with leadership we usually find that texts are centred on the leader. However, the process possesses another member of even greater importance embodied in the social group that forms around him or her. Thus, social actors need to reach a higher degree of sociability and to express, amongst other things, needs and goals, and they look for them openly in a chosen representative. And he or she, in turn, must fulfil the expectations of the group. In other words, the asymmetry of said relationship is inverted. Moreover, at the leader's end, we must discern between the person and the 'character'. This is how the particular game of leadership unfolds. The resulting construct accounts for the construction of a significant social feat.

Towards a new concept of leadership

In the present work we have posited some necessary guidelines to reformulate an essential pillar of leadership: the relationship group-leader. The set of enunciations that are developed are meant to establish the basic principles of the theoretical interpretation of this essential phenomenon of social life. In most works dealing with leadership we usually find that texts are centred on the leader. However, the process possesses another member of even greater importance embodied in the social group that forms around him or her. Thus, social actors need to reach a higher degree of sociability and to express, amongst other things, needs and goals, and they look for them openly in a chosen representative. And he or she, in turn, must fulfil the expectations of the group. In other words, the asymmetry of said relationship is inverted. Moreover, at the leader's end, we must discern between the person and the 'character'. This is how the particular game of leadership unfolds. The resulting construct accounts for the construction of a significant social feat.

Towards a new concept of leadership

In the present work we have posited some necessary guidelines to reformulate an essential pillar of leadership: the relationship group-leader. The set of enunciations that are developed are meant to establish the basic principles of the theoretical interpretation of this essential phenomenon of social life. In most works dealing with leadership we usually find that texts are centred on the leader. However, the process possesses another member of even greater importance embodied in the social group that forms around him or her. Thus, social actors need to reach a higher degree of sociability and to express, amongst other things, needs and goals, and they look for them openly in a chosen representative. And he or she, in turn, must fulfil the expectations of the group. In other words, the asymmetry of said relationship is inverted. Moreover, at the leader's end, we must discern between the person and the 'character'. This is how the particular game of leadership unfolds. The resulting construct accounts for the construction of a significant social feat.

Economic Implications of Enlargement. Bruges European Economic Policy (BEEP) Briefing 1/2002

The Eastern enlargement is about to be decided by the European Council. As expected, the “end game “ of the negotiations and assessments is heavily biased by a narrow perspective on net transfers, on income compensations to Central European farmers and on the psychological politics of a single “big bang “. None of these three so-called key items of the end game are of much relevance to appreciate the significance of enlargement. Net transfers have little to do with the costs and benefits of club membership for countries which pay, and can lead to addiction and lethargy rather than extra growth if market integration, macro-economic stability and domestic reforms are not taken serious (as the case of Greece before 1997 has demonstrated). Income compensations for Eastern farmers are crucial for this pressure group, and symbolically of some importance in domestic politics because of the perversity that rich farmers get more, but their absence is likely to serve the public interest in candidate countries far better. And being part of the big bang, as against getting in one or three years later, has assumed a dramatic meaning during this end game, far beyond its true proportions. This hectic European theatre tends to obscure what enlargement is mainly about, now that the stability and values have been secured for the peoples from Central Europe. In a guaranteed setting of peace, freedom and security, enlargement is about greater prosperity.

The Political Logic of Disintegration: Seven Lessons from the Soviet Collapse. CEPS Essay (No. 1), September 2012

In short, the European Union, as we know it, no longer exists. The very foundations on which it was built are eroding. Shared memories of the Second World War have faded away – half the 15- and 16-year-olds in German high schools do not know that Hitler was a dictator, while a third believe that he protected human rights. The collapse of the Soviet Union has stripped away the geopolitical rationale for European unity. The democratic welfare state that was at the heart of the post-war political consensus is under siege by, among other things, sheer demographics. And the prosperity that bolstered the European project’s political legitimacy is vanishing. More than six out of ten Europeans believe that the lives of today’s children will be more difficult than those of people from their own generation. Against this background, how unthinkable is the EU’s disintegration? Should Europeans make the mistake of taking the Union for granted? Should they assume that the Union would not collapse because it should not collapse? Here, Europe’s capacity to learn from the Soviet precedent could play a crucial part. For the very survival of the EU may depend on its leaders’ ability to manage a similar mix of political, economic and psychological factors that were in play in the process of the Soviet collapse. The game of disintegration is primarily a political one driven much more by the perceptions and misperceptions of the political actors than simply by the constellation of the structural factors – institutional and economic.

Michigan Stadium, Syracuse game, 1998

[Opening game of enlarged Michigan Stadium, attendance 111,012, view from the north]