Inhibition and working memory: effect of acute sleep deprivation on a random letter generation task]

The literature contains inconsistent data on the effects of acute sleep deprivation on the superior cognitive functions. The primary purpose of this study is to determine the effectiveness of inhibition, one of the functions of the working memory executive centre (EC), over an extended, 36-hour waking period. Inhibition is a cognitive mechanism whereby individuals ignore non-relevant information recorded in their working memory. We also tested the effects of a 36-hour period of acute sleep deprivation on simple reaction time. Twelve young, healthy volunteers (M = 21.5 years, sigma = 2.3) performed a random generation task involving letters and a simple reaction time psychomotor test over four sessions held at 10-hour intervals. Each participant was assigned a "constant routine." Participants were kept awake in a prone position within a room whose environment was held strictly constant (light, noise, temperature, meals, etc.). This control procedure provided assurance that any variation in participant performance was solely caused by sleep deprivation. The random generation task, nearly two minutes in length, consisted in verbally producing a sequence of 100 letters in a random fashion (i.e. by inhibiting, for example, alphabetical order) and by keeping to a set rhythm. Our assumption was that capacity for inhibition diminished as the number of hours of sleep deprivation increased. The simple reaction test, 10 minutes in length, involved pressing a button as swiftly as possible to cause a black square to disappear from a screen. In this case our assumption was that acute sleep deprivation alters simple reaction time. Analysis of variance (ANOVA) through repeated measures using the "sessions" factor as an intra-subject variable showed no significant changes in randomization indices of the random generation task, contrary to analysis of average simple reaction times. Participants' reaction times deteriorated over the first two minutes of the test during the night they were deprived of sleep. It would seem that the contradictory results of previous studies of the effects of acute sleep deprivation on the inhibition function would be due to errors in factor identification. In conclusion, the inhibition function, as measured during the performance of a brief task, seems to remain intact during an extended, 36-hour waking period. Simple reaction time assessed by means of a brief psychomotor test is affected during a night of sleep deprivation. The working-memory inhibition executive function shows greater resistance to acute sleep deprivation than does psychomotor reaction time for the performance of short tasks.     

A Kripke Semantics for the Logic of Gelfand Quantales

Gelfand quantales are complete unital quantales with an involution, *, satisfying the property that for any element a, if a b a for all b, then a a* a = a. A Hilbert-style axiom system is given for a propositional logic, called Gelfand Logic, which is sound and complete with respect to Gelfand quantales. A Kripke semantics is presented for which the soundness and completeness of Gelfand logic is shown. The completeness theorem relies on a Stone style representation theorem for complete lattices. A Rasiowa/Sikorski style semantic tableau system is also presented with the property that if all branches of a tableau are closed, then the formula in question is a theorem of Gelfand Logic. An open branch in a completed tableaux guarantees the existence of an Kripke model in which the formula is not valid; hence it is not a theorem of Gelfand Logic.     

Shaping the Field of Theology and Science: A Critique of Nancey Murphy

Nancey Murphy is a key second-generation figure in the field of religion and science. Through a variety of responsibilities, some of which are reviewed here, she has worked as a discipline builder over the last fifteen years. After trying to convey the general spirit of Murphy's work, the author focuses on five areas where readers might resist her conclusions, including her "postmodern" theory of scientific (and religious) knowledge and truth, her treatment of theology and science as "separate but equal," and her defense of physicalism.     

The effects of a programme of training in structured group counselling

This study examined the effects of a programmes of experiential training in structured group counselling, based on the approach of Sheldon Rose. Participants were 32 undergraduate and graduate students, divided into three groups, who participated in the group work as part of a course in Core Counseling skills. The groups met for two hours per week for eight weeks. At the end of each exercise the participants completed a 12-item questionnaire giving their evalution and experience of the exercise they had just finished. The questionnaires were initially factors analysed and produced three main factg43ors, labelled task orientation, cohesion and conflict. Factor scores were used for all subsequent analyses. A series of one-way analyses of variance showed how the groups reacted to the different exercises, and discriminant analysis was used to determine how the climate and method of the individual groups could be differentially characterised in terms of the questionnaire factors. It was concluded that the membership of structured groups may be a major determinant of the group climate and experience.     

Escaping Homelessness: The Influences of Self-Efficacy and Time Perspective on Coping With Homelessness1

This study explored whether self-efficacy and time perspective of homeless adults (N= 82) living in a shelter affected their coping strategies related to obtaining housing and employment. Participants with high self-efficacy searched more for housing and employment and stayed at the shelter for a shorter duration, whereas participants with low self-efficacy were more likely to request an extension of their stay at the shelter. Those high on future orientation had shorter durations of homelessness and were more likely to enroll in school and to report gaining positive benefits from their predicament, whereas those with a high present orientation had more avoidant coping strategies. Despite the predictive power of self-efficacy and future orientation of proactive search behaviors, there were no predictors of obtaining stable housing, which is a scarce resource in the area. However, a high present orientation predicted obtaining temporary housing. A present temporal perspective may be adaptive in finding short-term solutions to an unstable situation, such as homelessness. The role of time perspective in crisis situations is discussed, as well as the severe environmental constraints on the exercise of personal control over reality dictated by social, economic, and political forces.     

Coping with type 1 diabetes through emerging adulthood: Longitudinal associations with perceived control and haemoglobin A1c

Objective: This study, which is part of a larger longitudinal study focusing on the biopsychosocial functioning of emerging adults with type 1 diabetes, examined how perceived personal control, coping and HbA_1c relate to one another over time.

Design and main outcome measures: Emerging adults with type 1 diabetes (18–30 years old) participated in a two-wave longitudinal study spanning five years (N = 164 at Time 1). At both times, patients completed questionnaires on perceived control and coping (i.e. diabetes integration, avoidant coping and passive resignation). HbA_1c values were obtained from treating clinicians. We investigated the directionality of effects using cross-lagged path analysis.

Results: Higher HbA_1c values predicted relative decreases in diabetes integration and increases in avoidant coping five years later. Feeling less in control over diabetes predicted the use of passive coping over time. Passive coping predicted a relative decrease in perceived control five years later.

Conclusion: These findings indicate that tackling poor glycaemic control is not only important to avoid medical complications but also to prevent patients from resorting to more avoidant coping strategies. Furthermore, given the longitudinal interplay between perceived control and passive coping, it is important that intervention efforts include both cognitive and behavioural components to be effective.     

Reclaiming Evangelism

This paper introduces approaches to reclaiming evangelism, noting the challenges and opportunities of our changing global context, and stressing the importance of authentic witness. The author draws on the Council for World Mission's work promoting the development of missional congregations as life‐affirming communities and its statement identifying six conversation threads (the absence of God; secularism; issues of identity; how we affirm life; the sources we use to shape and nurture our faith; and how we overcome fear and violence in our societies and in the world) that need to be developed on Christian witness in a pluralist world.