Abstract.It is well known that leveraged exchange-traded funds (LETFs) do not reproduce the corresponding multiple of index returns over extended (quarterly or annual) investment horizons. For instance, in 2008 and early 2009, most LETFs underperformed the corresponding static strategies. In this paper, we study this phenomenon in detail. We give an exact formula linking the return of a leveraged fund with the corresponding multiple of the return of the unleveraged fund and its realized variance. This formula is tested empirically over quarterly horizons for 56 leveraged funds (44 double-leveraged and 12 triple-leveraged) using daily prices since January 2008 or since inception, according to the fund considered. The results indicate excellent agreement between the formula and the empirical data. The study also shows that leveraged funds can be used to replicate the returns of the underlying index, provided we use a dynamic rebalancing strategy. Empirically, we find that rebalancing frequencies required to achieve this goal are moderate-on the order of one week between rebalancings. Nevertheless, this need for dynamic rebalancing leads to the conclusion that LETFs as currently designed may be unsuitable for buy-and-hold investors.

Objectives:To determine the predictors of knowledge and awareness of concussion symptoms and outcomes through a survey of athletes, parents of players and coaches in sports settings in Canada.Methods:A cross-sectional survey of athletic communities in Canada was conducted. Respondents’ concussion knowledge score consists of responses to questions about the symptoms, diagnosis, and treatment of a concussion and the timing of return-to-sport post-concussion. The percentage of correct responses was defined as the “identification rate.” The extent to which participant factors affected the scores was examined by univariate and multivariate analyses.Results:Respondents were able to identify a mean of 80.6% of symptoms. Cognitive symptoms were most commonly known, and mental health symptoms associated with concussion were least known, and health professionals, coaches, and those with a personal history of concussion had the highest levels of overall knowledge. Language, age, educational level, annual household income, and traumatic brain injury history were good predictors of better concussion knowledge.Conclusion:Those designing and implementing interventions aimed at concussion management and prevention should ensure that younger, lower income, lower educational, non-English-speaking persons, and those without experience of traumatic brain injury or concussion be specifically accounted for in the design and implementation of interventions to prevent and treat concussion and mild traumatic brain injury.

Our findings indicate that underreporting of concussion among those players interviewed appears to be prevalent and associated with misconceptions about injury risk, and a culture that both reinforces and encourages underreporting with tacit or overt complicity of parents and coaches. Our findings support the need to alter the culture of violence and tough play in hockey by education, rule changes, economic measures, and changes in governance of the sport. Interviewing more stakeholders and policy makers would shed light on such potential interventions.

Objectives:Sport-related traumatic brain injuries are a significant public health burden, with hundreds of thousands sustained annually in North America. While sports offer numerous physical and social health benefits, traumatic brain injuries such as concussion can seriously impact a player’s life, athletic career, and sport enjoyment. The culture in many sports encourages winning at all costs, placing athletes at risk for traumatic brain injuries. As social media has become a central part of everyday life, the content of users’ messages often reflects the prevailing culture related to a particular event or health issue.Methods:We hypothesized that Twitter data might be useful for understanding public perceptions and misperceptions of sport-related traumatic brain injuries. We performed a content and sentiment analysis of 7483 Twitter® tweets related to traumatic brain injuries in sports collected during June and July 2013.Results:We identified five major themes. Users tweeted about personal traumatic brain injuries experiences, reported traumatic brain injuries in professional athletes, shared research about sport-related concussions, and discussed policy and safety in injury prevention, such as helmet use. We identified mixed perceptions of and sentiment toward traumatic brain injuries in sports: both an understanding that brain injuries are serious and disregard for activities that might reduce the public burden of traumatic brain injuries were prevalent in our Twitter analysis.Conclusion:While the scientific and medical community considers a concussion a form of traumatic brain injuries, our study demonstrates a misunderstanding of this fact among the public. In our current digital age, social media can provide useful insight into the culture around a health issue, facilitating implementation of prevention and treatment strategies.