Physiological responses to psychological stress: importance of adiposity in men aged 50-70 years

We tested the hypothesis that overweight/obese men aged 50–70 years will have a greater salivary cortisol, salivary alpha amylase and heart rate (HR) responses to psychological stress compared with age matched lean men. Lean (BMIZ20–25 kg/m2; nZ19) and overweight/obese (BMIZ27–35 kg/m2; nZ17) men (50–70 years) were subjected to a well-characterised psychological stress (Trier Social Stress Test, TSST) at 1500 h. Concentrations of cortisol and alpha amylase were measured in saliva samples collected every 7–15 min from 1400 to 1700 h. HR was recorded using electrocardiogram. Body weight, BMI, percentage body fat, resting systolic and diastolic blood pressure and mean arterial pressure were significantly higher (P!0.05) in overweight/obese men compared with lean men. Both groups responded to the TSST with a substantial elevation in salivary cortisol (372%), salivary alpha amylase (123%) and HR (22%). These responses did not differ significantly between the groups (time!treatment interaction for salivary cortisol, salivary alpha amylase and HR; PZ0.187, PZ0.288, PZ0.550, respectively). There were no significant differences between the groups for pretreatment values, peak height, difference between pretreatment values and peak height (reactivity) or area under the curve for salivary cortisol, salivary alpha amylase or HR (PO0.05 for all). The results showed that, for men with a moderate level of overweight/obesity who were otherwise healthy, the response of salivary cortisol, salivary alpha amylase and HR to acute psychological stress was not impaired.

Performing research as a method of analysis

This paper outlines a theatre-based research method undertaken as a means of analysing and representing data from a study into first-year teachers’ identity transformation. It reports on the processes employed, and the attempt by the researcher to bring together complimentary and innovative ways of interpreting interview data. Interview data from twelve teachers throughout their first year of teaching were scripted, rehearsed and performed to ‘expert’ audiences. The written script provided the basis for analysis of the teachers’ identity transformation as seen through their firsts – epiphanic and/or revelatory experiences that marked a moment of transition or transformation. The script served as an effective tool for data analysis, particularly when developing an understanding of the process of data reduction. Initially dissatisfied with the term ‘data reduction’, believing it to be counter-intuitive to ‘reduce’ the participants’ descriptions of their experiences, the process of scripting emphasised the importance of honing in on meaning, and reconciled such concerns by creating a snapshot of each participant’s first as representative of their experiences. Later, the performance revealed more nuanced understandings of the participants’ experiences as viewed through the eyes of the teacher-actors and audiences. The actors selected to represent the experiences of the first-year teachers in the performance were also teachers. The process of casting, and the teacher-actors’ experiences of rehearsing and performing the work ‘The First Time’ over the past two years will also be discussed. This paper concludes with some of the feedback from various audiences of both the performance and the written thesis from arts- and non-arts-based practitioners. Some feedback contends that the theatre-based method was less rigorous than other more ‘traditional’ methods. Such feedback prompts the consideration of weighing the benefits of employing theatre-based research against the risk of alienating some members of the audiences (both of the performance and the page). This paper includes live/digital excerpts of the theatre-based performance ‘The First Time’.

Restricting prey dispersal can overestimate the importance of predation in trophic cascades

Predators can affect prey populations and, via trophic cascades, predators can indirectly impact resource populations (2 trophic levels below the predator) through consumption of prey (density-mediated indirect effects; DMIEs) and by inducing predator-avoidance behavior in prey (trait-mediated indirect effects; TMIEs). Prey often employ multiple predator-avoidance behaviors, such as dispersal or reduced foraging activity, but estimates of TMIEs are usually on individual behaviors. We assessed direct and indirect predator effects in a mesocosm experiment using a marine food chain consisting of a predator (toadfish--Opsanus tau), prey (mud crab--Panopeus herbstii) and resource (ribbed musse--Geukensia demissa). We measured dispersal and foraging activity of prey separately by manipulating both the presence and absence of the predator, and whether prey could or could not disperse into a predator-free area. Consumption of prey was 9 times greater when prey could not disperse, probably because mesocosm boundaries increased predator capture success. Although predator presence did not significantly affect the number of crabs that emigrated, the presence of a predator decreased resource consumption by prey, which resulted in fewer resources consumed for each prey that emigrated in the presence of a predator, and reduced the overall TMIE. When prey were unable to disperse, TMIEs on mussel survival were 3 times higher than the DMIEs. When prey were allowed to disperse, the TMIEs on resource survival increased to 11-times the DMIEs. We found that restricting the ability of prey to disperse, or focusing on only one predator-avoidance behavior, may be underestimating TMIEs. Our results indicate that the relative contribution of behavior and consumption in food chain dynamics will depend on which predator-avoidance behaviors are allowed to occur and measured.

On the importance of the first observation in GLS detrending in unit root testing

First-differencing is generally taken to imply the loss of one observation, the first, or at least that the effect of ignoring this observation is asymptotically negligible. However, this is not always true, as in the case of generalized least squares (GLS) detrending. In order to illustrate this, the current article considers as an example the use of GLS detrended data when testing for a unit root. The results show that the treatment of the first observation is absolutely crucial for test performance, and that ignorance causes test break-down.

Active learning: the importance of developing a comprehensive measure

This article reports on an investigation into the validity of a widely used scale for measuring the extent to which higher education students employ active learning strategies. The scale is the active learning scale in the Australasian Survey of Student Engagement. This scale is based on the Active and Collaborative Learning scale of the National Survey of Student Engagement. The particular focus of the study was to investigate effects resulting from the addition of a small number of items to the active learning scale designed to capture some highly engaging, mostly online, activities. The items were developed in response to concerns that students studying in distance mode often report lower average scores on active learning scales than their on-campus counterparts. The additional items relate to activities such as working online with other students and faculty. The findings show that average scores on the Australasian Survey of Student Engagement/National Survey of Student Engagement scale increase significantly when the new items are included and that some differences between on-campus and distance education students narrow significantly. These findings have implications for the development of more robust and comprehensive instruments to measure active learning.

Seven heavens? The character and importance of afterlife belief among contemporary Australians

This article draws on in-depth qualitative interviews with 52 people to examine the meaning and character of afterlife belief among contemporary Australians. It explores the varieties of afterlife belief and considers the impact such beliefs have, particularly in relation to death and dying. The analysis reveals that afterlife belief is varied, individualistic and mainly arrived at with little to no reference to orthodox religious teaching. People variously believe in heaven, reincarnation, life on another planet or something more abstract. Those who follow faithfully a religious tradition are largely ignorant of detailed theological doctrines about life after death and like other kinds of believers, exercise their own authority and judgment over matters of belief.