Self-reported stress and psychophysiological reactivity in paramedics

Background: As an important group of health care professionals, paramedics accomplish sophisticated and frequently stressful tasks.

Design: The study investigated self-reported stress burden, self-reported health status, coping strategies, personality traits and psychophysiological reactivity in paramedics.

Methods: 30 paramedics were compared with 30 professionals from other disciplines, in terms of self-reported stress, physical complaints, coping strategies, personality traits and psychophysiological reactivity during aversive visual and acoustic stimuli, and cognitive challenge. Regression analyses were performed for the prediction of stress burden and physical complaints in paramedics according to coping and personality factors.

Results: Paramedics reported lower stress and less somatic complaints, and exhibited reduced electrodermal activity and heart rate responses to experimental stimuli, as well as higher respiratory sinus arrhythmia. They indicated less negative coping strategies, reduced empathy, and higher conscientiousness and sensation seeking. Higher self-reported stress burden and more physical symptoms were associated inter alia with more negative coping strategies, less conscientiousness and lower empathy.

Conclusion: The findings support the notion of reduced self-reported stress burden, and improved general health and stress resistance in paramedics. In addition to health benefits, stress tolerance may contribute to the prevention of performance decline during situations in which health and life are at stake.     

Rate of Torque Development and Feedforward Control of the Hip and Knee Extensors: Gender Differences

The purpose of this study was to determine whether women demonstrate decreased rate of torque development (RTD) of the hip and knee extensors and altered onset timing of the vastus lateralis and gluteus maximus during a drop-jump task when compared with men. On average, women demonstrated significantly lower normalized RTD of the hip extensors (women: 11.6 ± 1.3 MVT.s^?1, men: 13.1 ± 0.9 MVT.s^?1; p ≤ .01); however, there was no significant difference in knee extensor RTD. Women also demonstrated significantly earlier activation of their vastus lateralis (women: 206.0 ± 130.6 ms, men: 80.9 ± 69.6 ms; p ≤ .01) and gluteus maximus (women: 85.7 ± 58.6 ms, men: 54.5 ± 35.4 ms; p = .02). In both men and women, there was a significant negative correlation between the hip extensor RTD and the vastus lateralis electromyographic onset time (men: r = –.386, p = .046; women: r = –.531, p = .008). The study findings suggest that women may utilize a feedforward control strategy in which they activate their knee extensors earlier than men to compensate for deficits in hip extensor RTD. The impaired capacity to rapidly stabilize the hip and knee joints during dynamic maneuvers may contribute to the increased risk of anterior cruciate ligament injury observed in women.     

Prospective Elementary Teachers Learning to Reason Flexibly with Sums and Differences: Number Sense Development Viewed Through the Lens of Collective Activity

I present a viable learning trajectory for prospective elementary teachers’ number sense development with a focus on whole-number place value, addition, and subtraction. I document a chronology of classroom mathematical practices in a Number and Operations course. The findings provide insights into prospective elementary teachers’ number sense development. These include the role of standard algorithms and their relationship to the evolution of classroom mathematical practices that involve reasoning flexibly about number composition, sums, and differences.     

Bi-Directional Relationship Between Self-Regulation and Improved Eating: Temporal Associations With Exercise,Reduced Fatigue,and Weight Loss

ABSTRACT. Severely obese men and women (body mass index ≥ 35 ≤ 55 kg/m²; M_age = 44.8 years, SD = 9.3) were randomly assigned to a 6-month physical activity support treatment paired with either nutrition education (n = 83) or cognitive-behavioral nutrition (n = 82) methods for weight loss. Both groups had significant improvements in physical activity, fatigue, self-regulation for eating, and fruit and vegetable intake. Compared to those in the nutrition education group, participants in the behavioral group demonstrated greater overall increases in fruit and vegetable intake and physical activity. These group differences were associated with changes that occurred after Month 3. Increased physical activity predicted reduced fatigue, β = ?.19, p =.01. A reciprocal relationship between the mediators of that relationship, which were changes in self-regulation and fruit and vegetable intake, was identified. There was significantly greater weight loss over six months in the behavioral nutrition group when contrasted with the nutrition education group. Self-regulation for eating and fruit and vegetable intake were significant predictors of weight loss over both three and six months. Findings enabled a better understanding of psychosocial effects on temporal aspects of weight loss and may lead to more effective behavioral treatments for weight loss.     

Testing a bi-factor model to disentangle general and specific factors of motivation in self-determination theory

We examined the utility of the bi-factor model for disentangling general motivation and specific motivations (i.e., amotivation, external, introjected, identified, and intrinsic regulations) in relation to goal progress and physical activity (PA). Participants (N = 186 undergraduate students; M_age = 19.26 years) completed assessments of motivation and PA at Time 1. Four weeks later, PA and goal progress were assessed at Time 2. Results indicated that the exploratory bi-factor model specifying motivational regulations as the specific factors and general motivation as the general factor was a good fit to the data. Results of the structural equation model indicated that identified and intrinsic regulations and general motivation predicted concurrent PA at Time 1. A novel finding was that controlling for concurrent PA at Time 1, general motivation emerged as the only predictor of Time 2 goal progress and PA. Results highlight the importance of examining general motivation in addition to quality of motivation in tandem because general motivation emerged as the sole significant longitudinal predictor of PA outcomes.     

Sleep deprivation impairs object recognition in mice

Many studies in animals and humans suggest that sleep facilitates learning, memory consolidation, and retrieval. Moreover, sleep deprivation (SD) incurred after learning, impaired memory in humans, mice, rats, and hamsters. We investigated the importance of sleep and its timing in an object recognition task in OF1 mice subjected to 6h SD either immediately after the acquisition phase (0-6 SD) or 6h later (7-12 SD), and in corresponding undisturbed controls. Motor activity was continuously recorded with infrared sensors. All groups explored two familiar, previously encountered objects to a similar extent, both at the end of the acquisition phase and 24h later during the test phase, indicating intact familiarity detection. During the test phase 0-6 SD mice failed to discriminate between the single novel and the two familiar objects. In contrast, the 7-12 SD group and the two control groups explored the novel object significantly longer than the two familiar objects. Plasma corticosterone levels determined after SD did not differ from time-matched undisturbed controls, but were significantly below the level measured after learning alone. ACTH did not differ between the groups. Therefore, it is unlikely that stress contributed to the memory impairment. We conclude that the loss of sleep and the activities the mice engaged in during the SD, impaired recognition memory retrieval, when they occurred immediately after acquisition. The delayed SD enabled memory consolidation during the 6h when the mice were allowed to sleep, and had no detrimental effect on memory. Neither SD schedule impaired object familiarity processing, suggesting that only specific cognitive abilities were sensitive to the intervention. Sleep may either actively promote memory formation, or alternatively, sleep may provide optimal conditions of non-interference for consolidation.