Magnetically quantized continuum distorted waves.

A new derivation of continuum distorted-wave theory is presented. It is generalized to magnetically quantized continuum distorted waves. The context is analytic continuation of hydrogenic-state wave functions from below to above threshold, using parabolic coordinates and quantum numbers including m the magnetic quantum number. This continuation applies to excitation, charge transfer, ionization, and double and hybrid events for both light- and heavy-particle collisions. It is applied to the calculation of double-differential cross sections for the single ionization of the hydrogen atom and for a hydrogen molecule by a proton for electrons ejected in the forward direction at a collision energy of 50 keV and 100 keV respectively.

A controlled evaluation of diagnostic criteria in the development of a rheumatology expert system.

As an intermediate stage in the development of an expert system to support undergraduate teaching in rheumatology, a decision tree incorporating the diagnostic criteria to be used in the expert system was produced by a team of rheumatologists. In a controlled trial, 119 final-year medical students each diagnosed 10 rheumatology cases, drawn from a pool of 96 cases, with or without the aid of the decision tree. Students who used the decision tree correctly diagnosed the following conditions more frequently than the control group: polymyalgia rheumatica (p less than 0.05), myopathies (p less than 0.01), systemic lupus erythematosus (p less than 0.05), pyrophosphate arthropathy (p less than 0.05), seronegative spondylarthropathies (p less than 0.01), intra-articular bleeding (p less than 0.05) and traumatic synovitis (p less than 0.05). The overall diagnostic accuracy of the students who used the decision tree was 81% compared with 68% for the control group (p less than 0.001).

Intelligent dialogue based on statistical models of clinical decision-making.

The independence Bayesian model has been used widely in computer programs designed to support clinical decision-making. A reasoning strategy has been developed to enable these programs to conduct clinically pertinent dialogue and explain their reasoning. It has been implemented in a program for the diagnosis of acute abdominal pain based on the Bayesian model of de Dombal et al. Several features of the dialogue design have been adopted from artificial intelligence research, including shared initiative and critiquing. The program adopts a flexible goal-driven strategy, attempting to confirm the clinician's diagnosis or rule out the likeliest alternative. Symptoms and signs are selected in order of their expected weights of evidence in favour of the hypothesized disease.

A microcomputer based audit of fracture of the proximal femur in the elderly.

A microcomputer was used for patient record management and statistical analysis to study prospectively an elderly female population with femoral neck fracture. Of 150 patients studied, 58% presented with a cervical fracture and 42% with a trochanteric fracture. The patients with trochanteric fracture were significantly older than the patients with cervical fracture (P less than 0.001), required a longer stay in hospital (P less than 0.01) and returned to their previous environment less frequently. The proportion of trochanteric fractures increased with age. In view of the ageing population and the rising incidence of femoral neck fracture, these findings have important implications for the future allocation of hospital resources.