Health practices and hardiness as mediators in the stress-illness relationship

Two stress and illness models that include the joint mediating effects of health practices and hardiness were tested prospectively over a 2-month period. At the beginning of one academic quarter, 60 female and 26 male undergraduate students completed five subscales indexing hardiness. Stress, health practices, and illness for the prior month were assessed at this time as well as 1 and 2 months later. Stress was measured by the number of negatively rated stressors reported on the Life Experiences Survey. Health practices were measured by the Self Care Inventory. In the first model, illness was measured by the severity of physical symptoms reported on the Seriousness of Illness Rating Scale; in the second model, it was measured by the number of symptoms reported. Correlations between all measures of stress and illness were typical for life events research (r = .22 to .29). In both models, path analyses revealed that stress acted directly to affect illness as well as indirectly by changing health practices. Hardiness also had a direct effect on illness as well as in indirect effect through health practices. Hardiness did not appear to have a stress-buffering effect on illness; rather, its effects on illness appeared to be independent of its effects on stress. Implications for life events research are discussed.     

Cooperation,Knowledge, and Time: Alternating-time Temporal Epistemic Logic and its Applications

Branching-time temporal logics have proved to be an extraordinarily successful tool in the formal specification and verification of distributed systems. Much of their success stems from the tractability of the model checking problem for the branching time logic CTL, which has made it possible to implement tools that allow designers to automatically verify that systems satisfy requirements expressed in CTL. Recently, CTL was generalised by Alur, Henzinger, and Kupferman in a logic known as Alternating-time Temporal Logic (ATL). The key insight in ATL is that the path quantifiers of CTL could be replaced by cooperation modalities, of the form , where is a set of agents. The intended interpretation of an ATL formula is that the agents can cooperate to ensure that holds (equivalently, that have a winning strategy for ). In this paper, we extend ATL with knowledge modalities, of the kind made popular in the work of Fagin, Halpern, Moses, Vardi and colleagues. Combining these knowledge modalities with ATL, it becomes possible to express such properties as group can cooperate to bring about iff it is common knowledge in that . The resulting logic — Alternating-time Temporal Epistemic Logic (ATEL) — shares the tractability of model checking with its ATL parent, and is a succinct and expressive language for reasoning about game-like multiagent systems.     

Psychometric properties of the Spanish Beck Depression Inventory-II in a medical sample

The authors examined the psychometric properties of the Spanish Beck Depression Inventory-II (BDI-II; A. T. Beck, R. A. Steer, & G. K. Brown, 1996) in a sample of individuals undergoing hemodialysis. They performed a confirmatory factor analysis of a previously reported 2-factor solution for the English BDI-II derived from a medical sample. Results indicate that the established model for the English-speaking medical sample provided adequate fit in the present sample. Spanish BDI-II scores were not significantly associated with age or gender in their sample, but they were significantly associated with disease severity. Bilingual participants completed the inventory in both Spanish and English, and their data revealed that BDI-II total scores were similar across language administration. The preliminary data suggest that the Spanish BDI-II can be reliably used in medical samples.     

Hardiness and stress moderation: a test of proposed mechanisms

High and low hardy male and female undergraduates completed an evaluative threat task that was manipulated to influence appraisals of the task in a manner consistent with hardiness theory. High hardy subjects displayed higher frustration tolerance, appraised the task as less threatening, and responded to the task with more positive and less negative affect than did low hardy subjects. Although all subjects displayed increased heart rate (HR) in response to the experimental task, high hardy men displayed lower HR elevations during the task than did low hardy men. Hardiness did not influence HR responses among women. Manipulations of task appraisal revealed a similar pattern where men in the high hardiness appraisal conditions displayed lower levels of physiological arousal during the task than did men in the low hardiness appraisal conditions. Appraisal manipulations had either no effect or the opposite effect among women.     

On Agents That Have the Ability to Choose

We demonstrate ways to incorporate nondeterminism in a system designed to formalize the reasoning of agents concerning their abilities and the results of the actions that they may perform. We distinguish between two kinds of nondeterministic choice operators: one that expresses an internal choice, in which the agent decides what action to take, and one that expresses an external choice, which cannot be influenced by the agent. The presence of abilities in our system is the reason why the usual approaches towards nondeterminism cannot be used here. The semantics that we define for nondeterministic actions is based on the idea that composite actions are unravelled in the strings of atomic actions and tests that constitute them. The main notions used in defining this semantics are finite computation sequences and finite computation runs of actions. The results that we obtain meet our intuitions regarding events and abilities in the presence of nondeterminism.