Connecting post-release mortality to the physiological stress response of large coastal sharks in a commercial longline fishery

Bycatch mortality is a major factor contributing to shark population declines. Post-release mortality (PRM) is particularly difficult to quantify, limiting the accuracy of stock assessments. We paired blood-stress physiology with animal-borne accelerometers to quantify PRM rates of sharks caught in a commercial bottom longline fishery. Blood was sampled from the same individuals that were tagged, providing direct correlation between stress physiology and animal fate for sandbar (Carcharhinus plumbeus, N = 130), blacktip (C. limbatus, N = 105), tiger (Galeocerdo cuvier, N = 52), spinner (C. brevipinna, N = 14), and bull sharks (C. leucas, N = 14). PRM rates ranged from 2% and 3% PRM in tiger and sandbar sharks to 42% and 71% PRM in blacktip and spinner sharks, respectively. Decision trees based on blood values predicted mortality with >67% accuracy in blacktip and spinner sharks, and >99% accuracy in sandbar sharks. Ninety percent of PRM occurred within 5 h after release and 59% within 2 h. Blood physiology indicated that PRM was primarily associated with acidosis and increases in plasma potassium levels. Total fishing mortality reached 62% for blacktip and 89% for spinner sharks, which may be under-estimates given that some soak times were shortened to focus on PRM. Our findings suggest that no-take regulations may be beneficial for sandbar, tiger, and bull sharks, but less effective for more susceptible species such as blacktip and spinner sharks

Come back Marshall, all is forgiven? : Complexity, evolution, mathematics and Marshallian exceptionalism

Marshall was the great synthesiser of neoclassical economics. Yet with his qualified assumption of self-interest, his emphasis on variation in economic evolution and his cautious attitude to the use of mathematics, Marshall differs fundamentally from other leading neoclassical contemporaries. Metaphors inspire more specific analogies and ontological assumptions, and Marshall used the guiding metaphor of Spencerian evolution. But unfortunately, the further development of a Marshallian evolutionary approach was undermined in part by theoretical problems within Spencer's theory. Yet some things can be salvaged from the Marshallian evolutionary vision. They may even be placed in a more viable Darwinian framework.Peer reviewedFinal Accepted Versio

On possibility of measurement of the electron beam energy using absorption of radiation by electrons in a magnetic field

The possibility of the precise measurement of the electron beam energy using absorption of radiation by electrons in a static and homogeneous magnetic field in a range up to a few hundred GeV energies, was considered in [1]. With the purpose of experimental checking of this method in a range of several tens MeV energies, the possibility of measurement of absolute energy of the electron beam energy with relative accuracy up to 10^{-4} is examined in details.Comment: 14 pages, 10 figure

Relationship between concussion history and concussion knowledge, attitudes, and disclosure behavior in high school athletes

Objective: Examine the association between self-reported concussion history and measures of concussion knowledge, attitude, and disclosure behavior. Design: Cross-sectional survey. Setting: Classroom. Participants: A convenience sample of high school athletes (n = 167; mean age = 15.7 years) from multiple sports completed a validated survey. Independent Variables: Concussion history (main predictor) was defined as the number of self-recalled concussions during participants' high school career. Main Outcome Measures: The outcomes were recalled concussion disclosure behavior (3 measures) and scales assessing both concussion knowledge and concussion attitude. Results: A greater number of previous concussions was associated with worse attitude to concussion and negative concussion disclosure behavior. For every 3 additional self-recalled concussions, there was a mean decrease of 7.2 points (range of possible scores = 14-98) in concussion attitude score (P = 0.002), a 48% decrease in the self-reported proportion of concussion events disclosed (P = 0.013), and an increased prevalence of self-reported participation in games (67%) and practices (125%) while experiencing signs and symptoms of concussion (P < 0.001). Increased concussion history did not affect concussion knowledge score (P = 0.333). Conclusions: Negative trends in concussion disclosure behavior were identified in youth athletes with a positive history of concussion. Improving disclosure in this subgroup will require targeted efforts addressing negative attitude to concussion

Concussion Nondisclosure During Professional Career Among a Cohort of Former National Football League Athletes

Background: Despite a focus on the incidence and effects of concussion, nondisclosure of sports-related concussions among retired players from the National Football League (NFL) has yet to be examined. Purpose: Examine the prevalence of and factors associated with nondisclosure of sports-related concussions in former NFL athletes. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A sample of 829 former NFL players completed a general health survey. This historical cohort included players who had played before World War II to 2001. Respondents retrospectively recalled sports-related concussions that they sustained during their professional careers and whether at least one of these sports-related concussions was not reported to medical staff. We computed the prevalence of nondisclosure among those recalling sport-related concussions during their professional careers. Multivariable binomial regression estimated adjusted prevalence ratios (PR) with 95% confidence intervals (CIs) controlling for race/ethnicity, number of years played, primary position played, professional career concussion history, and playing era. Playing era was categorized by whether the majority of a player’s career was before or after a 1976 rule change to limit contact (“spearing”). Results: Overall, 417 (50.3%) respondents reported they had sustained a concussion and did not inform medical staff at least once during their professional playing career. Nonwhite respondents had a higher prevalence of nondisclosure than white/non-Hispanic respondents (adjusted PR = 1.19; 95% CI, 1.02-1.38). An interaction between professional career concussion history and playing era was also found (P =.08). Compared with those in the pre–spearing rule change group with 1 or 2 concussions, all other groups had larger prevalences of nondisclosure (increases ranging from 41% to 153% in multivariable models). Across concussion strata, nondisclosure prevalence was generally higher in the post–spearing rule change group than the pre–spearing rule change group, with the largest differences found among those with 1 or 2 concussions or those with 3 or 4 concussions. Conclusion: A large proportion of former NFL players in this historical cohort reported at least one instance of not disclosing sports-related concussions to medical staff. Future research on concussion nondisclosure needs to identify mechanisms to improve football players’ intentions to disclose concussion-related symptoms to health care providers and to equip health care providers with more effective strategies for timely identification of concussion

Bayesian approach to the assessment of the population-specific risk of inhibitors in hemophilia A patients : A case study

Background: Developing inhibitors is a rare event during the treatment of hemophilia A. The multifacets and uncertainty surrounding the development of inhibitors further complicate the process of estimating inhibitor rate from the limited data. Bayesian statistical modeling provides a useful tool in generating, enhancing, and exploring the evidence through incorporating all the available information. Methods: We built our Bayesian analysis using three study cases to estimate the inhibitor rates of patients with hemophilia A in three different scenarios: Case 1, a single cohort of previously treated patients (PTPs) or previously untreated patients; Case 2, a meta-analysis of PTP cohorts; and Case 3, a previously unexplored patient population - patients with baseline low-titer inhibitor or history of inhibitor development. The data used in this study were extracted from three published ADVATE (antihemophilic factor [recombinant] is a product of Baxter for treating hemophilia A) post-authorization surveillance studies. Noninformative and informative priors were applied to Bayesian standard (Case 1) or random-effects (Case 2 and Case 3) logistic models. Bayesian probabilities of satisfying three meaningful thresholds of the risk of developing a clinical significant inhibitor (10/100, 5/100 [high rates], and 1/86 [the Food and Drug Administration mandated cutoff rate in PTPs]) were calculated. The effect of discounting prior information or scaling up the study data was evaluated. Results: Results based on noninformative priors were similar to the classical approach. Using priors from PTPs lowered the point estimate and narrowed the 95% credible intervals (Case 1: from 1.3 [0.5, 2.7] to 0.8 [0.5, 1.1]; Case 2: from 1.9 [0.6, 6.0] to 0.8 [0.5, 1.1]; Case 3: 2.3 [0.5, 6.8] to 0.7 [0.5, 1.1]). All probabilities of satisfying a threshold of 1/86 were above 0.65. Increasing the number of patients by two and ten times substantially narrowed the credible intervals for the single cohort study (1.4 [0.7, 2.3] and 1.4 [1.1, 1.8], respectively). Increasing the number of studies by two and ten times for the multiple study scenarios (Case 2: 1.9 [0.6, 4.0] and 1.9 [1.5, 2.6]; Case 3: 2.4 [0.9, 5.0] and 2.6 [1.9, 3.5], respectively) had a similar effect. Conclusion: Bayesian approach as a robust, transparent, and reproducible analytic method can be efficiently used to estimate the inhibitor rate of hemophilia A in complex clinical settings

Quantifying heterogeneous responses of fish community size structure using novel combined statistical techniques

To understand changes in ecosystems, the appropriate scale at which to study them must be determined. Large marine ecosystems (LMEs) cover thousands of square kilometres and are a useful classification scheme for ecosystem monitoring and assessment. However, averaging across LMEs may obscure intricate dynamics within. The purpose of this study is to mathematically determine local and regional patterns of ecological change within an LME using empirical orthogonal functions (EOFs). After using EOFs to define regions with distinct patterns of change, a statistical model originating from control theory is applied (Nonlinear AutoRegressive Moving Average with eXogenous input – NARMAX) to assess potential drivers of change within these regions. We have selected spatial data sets (0.5° latitude × 1°longitude) of fish abundance from North Sea fisheries research surveys (spanning 1980–2008) as well as of temperature, oxygen, net primary production and a fishing pressure proxy, to which we apply the EOF and NARMAX methods. Two regions showed significant changes since 1980: the central North Sea displayed a decrease in community size structure which the NARMAX model suggested was linked to changes in fishing; and the Norwegian trench region displayed an increase in community size structure which, as indicated by NARMAX results, was primarily linked to changes in sea-bottom temperature. These regions were compared to an area of no change along the eastern Scottish coast where the model determined the community size structure was most strongly associated to net primary production. This study highlights the multifaceted effects of environmental change and fishing pressures in different regions of the North Sea. Furthermore, by highlighting this spatial heterogeneity in community size structure change, important local spatial dynamics are often overlooked when the North Sea is considered as a broad-scale, homogeneous ecosystem (as normally is the case within the political Marine Strategy Framework Directive)

Demographic, parental, and personal factors and youth athletes' concussion-related knowledge and beliefs

Context: Currently, significant attention is focused on improving care for patients with concussions through legislative mandates that include educational interventions. Few researchers have examined young athletes' concussion knowledge and the factors that may influence their knowledge. Objective: To use the socioecological model to examine demographic, parental, and personal factors associated with youth athletes' knowledge of concussion. Our ultimate goal is to inform the planning and implementation of youth sport concussion-related interventions. Design: Cross-sectional survey. Setting: Gymnasium and classroom. Patients or Other Participants: North Carolina and Arizona youth athletes (n ¼ 225; age ¼ 8 to 15 years) active in football, boys' or girls' soccer, boys' or girls' ice hockey, or boys' or girls' lacrosse in 2012-2013. Main Outcome Measure(s): Participants completed a validated, self-administered survey. The intention and belief measures were guided by the theory of planned behavior. Perceptions of concussion and intention to seek care were examined using descriptive statistics. Athletes' concussion knowledge was modeled using linear regressions and generalized estimating equations, with child demographic and personal factors and parental knowledge and attitudes about concussion as predictors. Results: Geography, sport, parental attitudes toward concussion, and athlete age were associated with athlete knowledge in the univariable analyses (P, .10). In the multivariable model, geographic location (North Carolina versus Arizona, mean difference [MD] ¼ 2.2, 95% confidence interval [CI] ¼ 1.1, 3.2), sport (girls' soccer versus girls' lacrosse, MD ¼ 2.2, 95% CI ¼ 0.7, 3.6), more favorable parental attitudes toward concussion (MD ¼ 1.2 for a 2-standard deviation shift; 95% CI ¼ 0.3, 2.1), and older age (.12 years, MD ¼ 1.6; 95% CI ¼ 0.5, 2.6) were associated with better knowledge about concussion. Conclusions: Geographic location, sport, parental attitudes about concussion, and athlete's age influenced athletes' concussion-related perceptions, indicating the need to address multiple levels of the socioecological model when targeting youth sport interventions. Parental interventions that translate to an improved culture of youth sport by improving youth athletes' perceptions and experiences are key areas for future work

A randomized controlled trial investigating the feasibility and adherence to an aerobic training program in healthy individuals

Context: Concussion management is moving from passive rest strategies to active interventions, including aerobic exercise therapy. Little information is available regarding the feasibility and adherence of these programs. Objectives: To determine whether an aerobic exercise training program intended for rehabilitation in people with concussion is feasible. Healthy, nonconcussed subjects were studied in this phase 1 trial. Design: Phase 1 parallel-group, randomized controlled trial in a sample of healthy (nonconcussed), recreationally active university students. Setting: Laboratory. Patients: 40 healthy university students. Methods: Participants were equally randomized to acute concussion therapy intervention (ACTIVE) training or nontraining groups. All participants completed maximal cardiopulmonary exercise tests on a stationary cycle ergometer at 2 test sessions approximately 14 days apart. During this 2-week study period, ACTIVE training participants completed six 30-minute cycling sessions, progressing from 60% to 80% of the participant's individualized maximal oxygen consumption. A subset of participants (NACTIVE = 12, Nnontraining = 11) wore physical activity monitors throughout the 2-week study period. Main Outcomes Measures: Study protocol and randomization effectiveness, exercise safety and adherence, and progressive intensity of the ACTIVE training procedures. Results: No adverse events occurred during any exercise sessions. Twelve ACTIVE training participants (60%) completed all training sessions, and every participant completed at least 4 sessions. Heart rate increased throughout the training period (P < .001), but symptom changes and training adherence remained stable despite the progressively increasing workload. ACTIVE training participants completed approximately 30 additional minutes of physical activity on training sessions days, although that was not statistically significant (P = .20). Conclusions: University-aged students were adherent to the ACTIVE training protocol. Future research should investigate the safety and feasibility of aerobic training programs in acutely concussed individuals to determine their appropriateness as a clinical rehabilitation strategy