An analysis of relational complexity in an air traffic control conflict detection task

Theoretical analyses of air traffic complexity were carried out using the Method for the Analysis of Relational Complexity. Twenty-two air traffic controllers examined static air traffic displays and were required to detect and resolve conflicts. Objective measures of performance included conflict detection time and accuracy. Subjective perceptions of mental workload were assessed by a complexity-sorting task and subjective ratings of the difficulty of different aspects of the task. A metric quantifying the complexity of pair-wise relations among aircraft was able to account for a substantial portion of the variance in the perceived complexity and difficulty of conflict detection problems, as well as reaction time. Other variables that influenced performance included the mean minimum separation between aircraft pairs and the amount of time that aircraft spent in conflict.

The role of BNP testing in heart failure

Brain natriuretic peptide (BNP) levels are simple and objective measures of cardiac function. These measurements can be used to diagnose heart failure, including diastolic dysfunction, and using them has been shown to save money in the emergency department setting. The high negative predictive value of BNP tests is particularly helpful for ruling out heart failure. Treatment with angiotensin-converting enzyme inhibitors, angiotensin-II receptor blockers, spironolactone, and diuretics reduces BNP levels, suggesting that BNP testing may have a role in monitoring patients with heart failure. However, patients with treated chronic stable heart failure may have levels in the normal range (i.e., BNP less than 100 pg per mL and N-terminal proBNP less than 125 pg per mL in patients younger than 75 years). Increases in BNP levels may be caused by intrinsic cardiac dysfunction or may be secondary to other causes such as pulmonary or renal diseases (e.g., chronic hypoxia). BNP tests are correlated with other measures of cardiac status such as New York Heart Association classification. BNP level is a strong predictor of risk of death and cardiovascular events in patients previously diagnosed with heart failure or cardiac dysfunction.

Cognitive deficits associated with cancer: A model of subjective and objective outcomes

Cancer and its treatment can affect many different aspects of quality of life. As a construct measured subjectively, quality of life shows an inconsistent relationship with objective outcome measures. That is, sometimes subjective and objective outcomes correspond with each other and sometimes they show little or no relationship. In this article, we propose a model for the relationship between subjective and objective outcomes using the example of cognitive function in people with cancer. The model and the research findings on which it is based help demonstrate that, in some circumstances, subjective measures of cognitive function correlate more strongly with psychosocial variables such as appraisal, coping, and emotions than with objective cognitive function. The model may provide a useful framework for research and clinical practice in quality of life for people with cancer.

Legislative and regulatory measures for preventing alcohol-related drownings and near-drownings

Objective: Alcohol contributes to about 30% of drowning fatalities associated with recreational aquatic activity and to 35% of drownings associated with boating. We consider regulatory and legislative strategies for preventing such deaths. Methods: We contacted water police in each Australian State and Territory to identify legislation creating alcohol-related offences for operators of recreational boats in their jurisdiction and to determine whether they conducted random breath testing (RBT). We also sought information from all 152 (81 urban and 71 rural) local government councils in NSW regarding restrictions on consumption of alcohol in public places within their shires. Results: Four Australian States (New South Wales, Queensland, Victoria and South Australia) have legislation prescribing maximum blood alcohol concentrations (BACs) for operators of recreational boats; all support this with RBT Western Australia, Tasmania and the Australian Capital Territory define more general offences for operating vessels while under the influence, of alcohol. Prohibitions or restrictions on consumption of alcohol in public places exist in 78 of the 86 shires in NSW that responded: 69 councils had alcohol-free zones, 53 restricted consumption of alcohol in public parks and reserves, and 33 had prohibitions or restrictions in some aquatic environments. Conclusions/implications: Legislation restricting BACs for recreational boat operators should be adopted in all Australian States and Territories. Optimal legislation would require that all occupants of recreational boats are required to comply with prescribed BAC levels, including when vessels are at anchor. Extension of by-laws prohibiting or restricting the consumption of alcohol specifically in aquatic environments warrants consideration.