Transoceanic pathogen transfer in the age of sail and steam.

In the centuries following Christopher Columbus's 1492 voyage to the Americas, transoceanic travel opened unprecedented pathways in global pathogen circulation. Yet no biological transfer is a single, discrete event. We use mathematical modeling to quantify historical risk of shipborne pathogen introduction, exploring the respective contributions of journey time, ship size, population susceptibility, transmission intensity, density dependence, and pathogen biology. We contextualize our results using port arrivals data from San Francisco, 1850 to 1852, and from a selection of historically significant voyages, 1492 to 1918. We offer numerical estimates of introduction risk across historically realistic ranges of journey time and ship population size, and show that both steam travel and shipping regimes that involved frequent, large-scale movement of people substantially increased risk of transoceanic pathogen circulation.

Using cognitive load theory to develop an emergency airway management curriculum: the Queen's University Mastery Airway Course (QUMAC).

Emergency airway management requires the simultaneous coordination of clinical reasoning and therapeutic interventions in the complex and time-sensitive setting of emergency resuscitation. The cognitive demand associated with these situations is invariably high and must be taken into consideration when designing training programs for this core professional competency. The four-component instructional design model (4C/ID), based on cognitive load theory, was used to develop a 1-year longitudinal airway management curriculum for Emergency Medicine residents. The simulation-based curriculum was designed with the goal of facilitating the construction and automation of schemas by individual residents in preparation for the high cognitive demand associated with emergency airway management in the clinical environment.

RéSUMé: La gestion des voies aériennes en urgence nécessite la coordination simultanée du raisonnement clinique et des interventions thérapeutiques dans le cadre complexe et sensible au temps de la réanimation d'urgence. La demande cognitive associée à ces situations est invariablement élevée et doit être prise en considération lors de la conception des programmes de formation pour cette compétence professionnelle essentielle. Le modèle de conception pédagogique à quatre composantes (4C/ID), fondé sur la théorie de la charge cognitive, a été utilisé pour élaborer un programme longitudinal de gestion des voies aériennes d'un an à l'intention des résidents en médecine d'urgence.

The impact of childhood sexual abuse in anorexia nervosa.

OBJECTIVE: The aim of this study was to examine the impact of childhood sexual abuse (CSA) on clinical characteristics and premature termination of treatment in anorexia nervosa (AN). METHOD: The participants were 77 consecutive patients with AN admitted to an inpatient eating disorders unit. The patients were assessed in terms of eating disorder symptoms, general psychopathology, and CSA history at admission to hospital. RESULTS: Thirty-seven patients (48%) reported a history of CSA before the onset of the eating disorder. Individuals with a history of CSA reported significantly greater psychiatric comorbidity, including higher levels of depression and anxiety, lower self-esteem, more interpersonal problems, and more severe obsessive-compulsive symptoms. Patients with the binge-purge subtype of AN (AN-BP) were significantly more likely to report a history of CSA prior to the onset of the eating disorder as compared with patients with the restricting subtype (AN-R) of the illness (65% of the AN-BP patients vs. 37% of the AN-R patients; p<.02). Contrary to our predictions, abused patients were not significantly more likely to dropout of treatment overall. However, patients of the binge-purge subtype (AN-BP) with a history of CSA were significantly more likely to terminate treatment prematurely as compared with the other patients. CONCLUSIONS: Consistent with previous findings, the present results indicate that the prevalence of CSA is high among individuals seeking inpatient treatment for AN. A history of CSA was associated with greater psychiatric disturbance overall and a higher rate of dropout for patients of the binge-purge subtype.

Predictors of premature termination of inpatient treatment for anorexia nervosa.

OBJECTIVE: The authors examined predictors of premature dropout from a voluntary specialized inpatient treatment program for anorexia nervosa. METHOD: One hundred sixty-six consecutive patients with anorexia nervosa received an admission assessment that consisted of a diagnostic interview and psychometric measures of core eating pathology and associated psychopathology. Survival analysis was used to examine the rate, timing, and prediction of dropout. Predictors included a variety of clinical, demographic, and psychometric variables. RESULTS: Compared with program completers, program dropouts were more likely to have the binge eating/purging type of anorexia nervosa (65% versus 26%), had lower restraint scores, and reported more intense maturity fears and concerns about weight. CONCLUSIONS: Patients with the binge eating/purging type of anorexia nervosa are significantly less likely to complete inpatient treatment for the disorder.

Healthy Schools-Healthy Kids: a controlled evaluation of a comprehensive universal eating disorder prevention program.

This study was a controlled evaluation of a comprehensive school-based universal prevention program involving male and female students, parents, teachers, school administrators and local public health professionals. A total of 982 male and female Grades 6 and 7 middle school students (and 91 teachers/school administrators) completed self-report surveys at baseline on measures of body satisfaction, internalization of media ideals, size acceptance, disordered eating, weight-based teasing, weight loss and muscle-gaining behaviours, and perceptions of school climate (teachers only). Eighty-four percent of the students repeated the surveys immediately following the 8-month school-wide intervention and 71% again 6 months later. Repeated measures ANCOVAs revealed that participation in the Healthy Schools-Healthy Kids (HS-HK) program had a positive influence by reducing the internalization of media ideals among male and female students and by reducing disordered eating among female students. The program was also associated with reductions in weight-loss behaviours among the students, although this effect was lost by the 6-month follow-up. When the intervention students were sub-divided into low versus high-risk groups, the high-risk group appeared to benefit most from the intervention with significant reductions in internalization of media ideals, greater body satisfaction, and reduced disordered eating over time. There were no intervention effects for teachers. Challenges of engaging teachers in prevention are discussed.

Correlates of weight loss and muscle-gaining behavior in 10- to 14-year-old males and females.

BACKGROUND: This study examined the influence of appearance and social acceptance esteem, awareness and internalization of media stereotypes, body size acceptance, and teasing on the weight loss and muscle-gaining behaviors of 10- to 14-year-old boys and girls. METHODS: Male (n = 670) and female (n = 788) students were drawn from one of four public senior middle schools (grades 6-8) in Southern Ontario as part of a longitudinal outcome-based study. Students' baseline self-report questionnaires, measuring the above variables, were analyzed for the purposes of this study. RESULTS: A higher percentage of girls reported engaging in weight loss behaviors, whereas a higher percentage of boys admitted to muscle gaining and the use of specific weight control methods such as laxative use and vomiting. Regression analyses revealed that internalization of media messages and body size acceptance were equally predictive of boys' weight loss and muscle-gaining behaviors, while teasing was found to also predict their muscle-gaining behavior. Among the girls, appearance esteem, internalization of media stereotypes, and body size acceptance were predictive of weight loss behaviors. None of the study variables were predictive of girls' muscle-gaining behavior. CONCLUSIONS: Weight loss and muscle-gaining behaviors appear to have their onset in children as young as 10 years. The findings support the need for prevention programs that focus on media literacy and ways to decrease weight-based teasing in the school setting.

Female adolescents with anorexia nervosa and their parents: a case-control study of exercise attitudes and behaviours.

BACKGROUND: Few studies of physical activity in patients with anorexia nervosa (AN) have included a suitable control group. Nor has such research considered the influence of parents' activity on that of their children. Our first prediction was that adolescents with AN would be significantly more active than healthy controls both prior to, and during, the progression of their disorder. We also expected that the activity levels of parents and their daughters would be correlated, and that this relationship would be stronger in patient than control families. Finally, we expected that the AN parents would be more active and report a greater commitment to exercise than the control parents. METHOD: In a case-control design, we employed multiple indicators of physical activity from adolescent females and their parents, using longitudinal, retrospective, self-report measurements. RESULTS: AN patients were significantly more active than controls both during the course of their disorder and prior to its onset. Parents' activity related to their daughter's activity, but this relationship was not stronger in the parents of the patients. CONCLUSIONS: Future research is needed to determine whether the relationship between parents' and children's activity levels reflects environmental or genetic influences, or a combination of both factors. The important observation of a significant increase in patients' activity levels at least a year prior to diagnosis of the disorder suggests that enhanced physical activity may play a role in the development of the disorder. This may also serve as an early warning sign of a subclinical eating disorder in adolescent girls.

Dieting among preadolescent and young adolescent females.

We examined the prevalence of dieting and negative eating attitudes among 2279 females (aged 10-14 years) in southern Ontario. Self-report questionnaires revealed that 29.3% of the girls were currently trying to lose weight and 10.5% had scores greater than the clinical threshold for disordered eating (Children's version of the Eating Attitudes Test [ChEAT] score > or = 20). Those with elevated ChEAT scores were more likely than those with lower scores to be engaged in dieting and other extreme weight control methods.

Factors affecting performance on a target monitoring task employing an automatic tracker.

The experiments in this paper examined the extent to which performance on a task employing an automatic tracker was similar to performance on tasks employing other types of automation that have been studied more extensively. Automated target tracking is being used in many sensor and navigation systems to improve performance and help the operator cope with increased data loads. With many automated systems these goals are not met. In particular, the operator often misses errors made by the automated system and may report no decrease in workload. Several hypotheses have been offered for the operator's failure to monitor an automated system adequately. These include lack of experience with the manual task, a vigilance decrement, complacency, and inappropriate level of automation. The relevance of each of these hypotheses to failure to monitor an automatic tracker adequately was examined. Performance and perceived workload on a target tracking task employing an automatic tracker, in which participants had to detect and then update the position of several targets (e.g. ships) at regular intervals, were measured as a function of number of targets, training with the manual task, experience, and time on task. The results suggested that failure to detect errors made by the automated system was due largely to the lack of visibility of the automation errors relative to other errors. However, complacency could not be ruled out entirely. Unlike some other tasks, the availability of a reliable automatic tracker did lead to a substantial reduction in perceived workload.

Looking good-family focus on appearance and the risk for eating disorders.

OBJECTIVE: Evidence suggests that eating-disordered families are overly concerned with social appearance and physical attractiveness. However, some argue that parental values are not sufficient to produce disordered eating in their offspring unless combined with certain third-factor effects of the child such as a psychological or biologic vulnerability. We tested this hypothesis by predicting that proneness to anxiety (neuroticism) and a family appearance focus would relate interactively (after controlling for body size) to a measure of weight preoccupation. METHOD: Data from 158 healthy young women were used in the analyses. RESULTS: Statistical analyses confirmed our hypothesis in a multiple regression model that accounted for 42% of the variance in weight preoccupation. DISCUSSION: Findings support the view that family risk factors have a more potent influence on young women who are easily made anxious-perhaps because they are more sensitive to, or more likely to internalize, pressures and expectations to conform to family values.

School-based peer support groups: a new approach to the prevention of disordered eating.

The goal of the present study was to evaluate the effectiveness of a school-based peer support group designed to improve body esteem and global self-esteem and to reduce negative eating attitudes and behaviors. A total of 214 girls in grades 7 and 8, 115 of whom were in the control group, completed self-report questionnaires immediately before and following the intervention, and three months later. The findings revealed that participation in the 10-session group, facilitated by public health nurses, led to increases in weight-related esteem and decreases in dieting. The role of peer support groups in the prevention of disordered eating is discussed.

Replication of a peer support program designed to prevent disordered eating: is a life skills approach sufficient for all middle school students?

The evaluation of a school-based peer support group previously shown to improve body esteem and global self-esteem and reduce dieting in young adolescent girls was replicated in the present study. A total of 282 girls in grades 7 and 8, 196 of whom were in the control group, completed self-report questionnaires immediately before and after the life skills intervention, and 3 months later. Contrary to the findings reported in the original study, participation in the 10-session peer support group did not lead to improvements in body esteem or eating attitudes and behaviors beyond what was experienced by the control group. Interestingly, participants of the current intervention group exhibited higher disordered eating scores at baseline than those participants in the original study. Implications for matching prevention curriculum with the developmental and symptom levels of students are discussed.