Procedure compilation in the refinement calculus

High-level language program compilation strategies can be proven correct by modelling the process as a series of refinement steps from source code to a machine-level description. We show how this can be done for programs containing recursively-defined procedures in the well-established predicate transformer semantics for refinement. To do so the formalism is extended with an abstraction of the way stack frames are created at run time for procedure parameters and variables.

Science-policy in environmental and health risk assessment: if we cannot do without, can we do better?

How can empirical evidence of adverse effects from exposure to noxious agents, which is often incomplete and uncertain, be used most appropriately to protect human health? We examine several important questions on the best uses of empirical evidence in regulatory risk management decision-making raised by the US Environmental Protection Agency (EPA)'s science-policy concerning uncertainty and variability in human health risk assessment. In our view, the US EPA (and other agencies that have adopted similar views of risk management) can often improve decision-making by decreasing reliance on default values and assumptions, particularly when causation is uncertain. This can be achieved by more fully exploiting decision-theoretic methods and criteria that explicitly account for uncertain, possibly conflicting scientific beliefs and that can be fully studied by advocates and adversaries of a policy choice, in administrative decision-making involving risk assessment. The substitution of decision-theoretic frameworks for default assumption-driven policies also allows stakeholder attitudes toward risk to be incorporated into policy debates, so that the public and risk managers can more explicitly identify the roles of risk-aversion or other attitudes toward risk and uncertainty in policy recommendations. Decision theory provides a sound scientific way explicitly to account for new knowledge and its effects on eventual policy choices. Although these improvements can complicate regulatory analyses, simplifying default assumptions can create substantial costs to society and can prematurely cut off consideration of new scientific insights (e.g., possible beneficial health effects from exposure to sufficiently low 'hormetic' doses of some agents). In many cases, the administrative burden of applying decision-analytic methods is likely to be more than offset by improved effectiveness of regulations in achieving desired goals. Because many foreign jurisdictions adopt US EPA reasoning and methods of risk analysis, it may be especially valuable to incorporate decision-theoretic principles that transcend local differences among jurisdictions.

Solaria use in Queensland, Australia

Objective: To describe the demographics of solarium users and the correlates of solarium use in Queensland. Methods: A cross-sectional survey of 9,419 Queensland residents was conducted via an anonymous computer-assisted telephone interview. Results: Overall, 8.8% of the respondents had ever used a solarium and less than 1% had used a solarium in the previous year. Results indicated that users were more likely to be female and younger than non-users, and less than half of the users signed a consent form, suggesting that they had not been made aware of the associated risks by operators. Conclusions: The Queensland Cancer Risk Study was one of the first population-based studies to address solarium use in this State and highlights that the use of solariums in Queensland is low in comparison to other countries. Implications: There is no regulation of compliance with guidelines. It may become necessary to make compliance with the guidelines mandatory to effectively communicate the associated risks.

Task substitution: where to from here?

Meeting future health workforce needs is a challenge for all health professionals.

Verifying data refinements using a model checker

In this paper, we consider how refinements between state-based specifications (e.g., written in Z) can be checked by use of a model checker. Specifically, we are interested in the verification of downward and upward simulations which are the standard approach to verifying refinements in state-based notations. We show how downward and upward simulations can be checked using existing temporal logic model checkers. In particular, we show how the branching time temporal logic CTL can be used to encode the standard simulation conditions. We do this for both a blocking, or guarded, interpretation of operations (often used when specifying reactive systems) as well as the more common non-blocking interpretation of operations used in many state-based specification languages (for modelling sequential systems). The approach is general enough to use with any state-based specification language, and we illustrate how refinements between Z specifications can be checked using the SAL CTL model checker using a small example.

Videophone support for an eight-year-old boy undergoing paediatric bone marrow transplantation

We report the use of an Internet-based videophone to support a child undergoing bone marrow transplantation (BMT). Over the Christmas period, an eight-year-old boy with an underlying diagnosis of attention-deficit/hyperactivity disorder (ADHD) and a history of absconding and aggressive non-compliant behaviour was treated by BMT. We installed an Internet-based videophone in the patient's hospital room two days post-transplant. A second videophone was installed in the patient's home and used the existing home telephone line. In all, 14 videophone calls were made over a nine-day period. The videophone improved interfamily social and emotional support, and appeared to reduce some of the inherent anxiety and distress resulting from paediatric bone marrow transplantation.

Realtime telemedicine

Telemedicine conducted via prerecorded interaction is more convenient than that using realtime interaction. On the other hand, a realtime consultation allows an immediate result to be obtained and there is likely to be a strong educational component for the remote practitioner. The use of the telephone is under-rated in telemedicine. Telephones have been used in outpatient follow-up, mental health, help lines and support groups. Telephones (fixed and mobile) have also been used for data transfer (e.g. for transmission of electrocardiograms). Realtime transfer of still images has been used in telepathology for many years, and more recently for rapid assessment of injuries. Realtime transfer of video images has been widely explored, perhaps most successfully in telepsychiatry. Some realtime telemedicine applications have been taken up with enthusiasm, even if formal evidence of cost-effectiveness may be lacking. Teleradiology and telepsychiatry are two examples where widespread adoption is beginning to occur. Other forms of realtime telemedicine represent 'niche' applications. That is, they appear to be both successful and sustainable in the centres where they were pioneered, but have not been adopted elsewhere. Teledialysis and teleoncology are examples of this type. The patchy diffusion of telemedicine is something that is not yet well understood.

Psychometric properties of the Chinese version of the diabetes empowerment scale

Metabolic control is central to positive clinical outcome in patients with diabetes. Empowerment has been linked to metabolic control in this clinical group. The current study sought to determine key psychometric properties of the Chinese version of the Diabetes Empowerment Scale (C-DES) and to explore the relationship of the C-DES sub-scales to metabolic control in 189 patients with a diagnosis of diabetes. Confirmatory factor analysis established that the five sub-scales of the C-DES offered a highly satisfactory fit to the data. Furthermore, C-DES sub-scales were found to have generally acceptable internal consistency and divergent reliability. However, convergent reliability of C-DES sub-scales could not be established against metabolic control. It is concluded that future research needs to address ambiguities in the relationship between empowerment and metabolic control in order to afford patients an evidenced-based treatment package to assure optimal metabolic control.