A Capstone Course for Senior Medical Students: from Innovative Elective to Required Core Curriculum

We describe our institution's development and implementation of our Capstone course from a small elective course to the only required fourth-year course. The course's structure evolved from mostly didactic to one including various workshops and simulation sessions. Course content has become increasingly specialty-specific. Implementation requires high faculty and resident involvement. Evaluations indicate a positive impact of the course on participants' self-reported confidence and residency preparedness. Assessment remains pass/fail with more specialty-specific questions. As steadily increasing numbers of medical schools are developing transition to residency courses, we share our Capstone course's evolution and lessons learned over the past nine years.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40670-023-01880-2.

The History of the Post-Graduate Medical and Nursing Officers (PGMNO) course in the British Army

Military medicine has been evolving for over 5000 years of recorded civilisation and conflict. The Army Medical Services performed poorly during the Crimean War and the British Army introduced a professional training course for medical officers in 1860. The Army Medical School and the predecessor of today's Post-Graduate Medical and Nursing Officers (PGMNO) course have had to adapt to changes in British foreign policy and military requirements. The Army Medical School instigated a rigorous scientific medical training which led to major advances in the study of tropical diseases and trauma medicine. These advances were quickly included in the training of future cohorts. Although the Army Medical School has now closed, the PGMNO course thrives at its new location at the Defence Medical Academy, Whittington. Modern general duties medical officers (GDMOs) must be able to provide medical care in a range of austere environments, including humanitarian relief and conflict zones. New clinicians complete their basic military training before completing the PGMNO course and the Diploma in the Medical Care of Catastrophes. This programme ensures that GDMOs and military nurse practitioners gain a wide knowledge of the latest military and humanitarian medicine. The current era will require clinicians who are competent generalists, who can perform in small teams in dispersed locations. This article summarises the development of the British Army's PGMNO course and the evolution of its syllabus as part of the Humanitarian and Disaster Relief Operations special issue of BMJ Military Health.

Competence in Decision Making: Setting Performance Standards for Critical Care

BACKGROUND

Health care professionals must be able to make frequent and timely decisions that can alter the illness trajectory of intensive care patients. A competence standard for this ability is difficult to establish yet assuring practitioners can make appropriate judgments is an important step in advancing patient safety. We hypothesized that simulation can be used effectively to assess decision-making competence. To test our hypothesis, we used a "standard-setting" method to derive cut scores (standards) for 16 simulated ICU scenarios targeted at decision-making skills and applied them to a cohort of critical care trainees.

METHODS

Panelists (critical care experts) reviewed digital audio-video performances of critical care trainees managing simulated critical care scenarios. Based on their collectively agreed-upon definition of "readiness" to make decisions in an ICU setting, each panelist made an independent judgment (ready, not ready) for a large number of recorded performances. The association between the panelists' judgments and the assessment scores was used to derive scenario-specific performance standards.

RESULTS

For all 16 scenarios, the aggregate panelists' ratings (ready/not ready for independent decision making) were positively associated with the performance scores, permitting derivation of performance standards for each scenario.

CONCLUSIONS

Minimum competence standards for high-stakes decision making can be established through standard-setting techniques. We effectively identified "front-line" providers who are, or are not, ready to make independent decisions in an ICU setting. Our approach may be used to assure stakeholders that clinicians are competent to make appropriate judgments. Further work is needed to determine whether our approach is effective in simulation-based assessments in other domains.

Can a weight management conditioning course help with armed forces recruitment?

British Armed Forces are facing the most significant recruitment crisis since 2010. An important contributing factor to the recruitment crisis is the rise in obesity of the UK population. At Army Training Centre Pirbright, a weight management programme (WMP) has been established for recruits who have failed their initial medical assessment (IMA). To determine the proportion of recruits who entered the WMP and passed basic and initial trade training, allowing entry into the British Army. Retrospective service evaluation of recruits entering WMP from inception in April 2015 to August 2018. Medical records were used to assess whether recruits completed initial training. 72.3% of recruits included in the WMP who would have previously failed their IMA because of a high body mass index (BMI) passed basic and initial trade training. This evaluation demonstrates potential for candidates otherwise excluded based on BMI. This WMP delivers structured nutritional support and encourages physical training. Once a BMI enters the accepted range, recruits could enter basic training. This WMP would deliver structured nutritional support and encourage physical training, with the aim of promoting healthy lifestyles. Neither the Royal Navy nor the Royal Air Force currently have a WMP. There is potential for WMPs to be introduced to all three services. UK Armed Forces face a recruitment crisis and need to be adaptable with a population where obesity is prevalent. At Pirbright 72.3% of candidates in the WMP passed basic and initial trade training.

Combined antegrade and retrograde access to difficult ureters: revisiting the rendezvous technique

INTRODUCTION

Complex ureteric strictures present a significant challenge to the endourologist and uro-radiologist. Multiple separate interventions to try to cross the stricture are often attempted. We describe our experience managing a heterogenous patient group using the 'rendezvous' procedure.

METHODS AND MATERIALS

16 patients and 18 ureters (one bilateral procedure, and two separate procedures in one patient) underwent rendezvous procedures. Seven patients had coexisting ureteric calculi treated. Each case was followed up for between 3 months and 5 years.

RESULTS

In 16/18 ureters there was technical success at time of surgery; successfully crossing the stricture, allowing ureteroscopic access to the ureter, dilating and/or stenting the ureter. 2/18 were unsuccessful; one secondary to advanced malignancy resulting in a uretero-vaginal fistula and the second a failure to remove a retained, displaced ureteric stent. Of the 18 ureteric procedures; 7/18 were stent free at 3 months, improving to 8/18 stent free at 6 months. 4/18 remained nephrostomy dependent (failure of drainage despite stent or failure to stent) at 3 months, increasing to 6/18 being nephrostomy dependent at 6 months. 1/16 remained dialysis dependent with a nephrostomy tube. For those procedures involving ureteric calculi, 6/7 were stone free and 1/5 had a persistent stone fragment requiring further intervention.

CONCLUSIONS

A combined approach may decrease the number of separate interventions required, with the aim of removing the need for a long-term nephrostomy, as well as providing opportunity to treat ureteric calculi in the context of stricture disease. Our experience has been that where the rendezvous has been required to treat strictures caused by malignant extrinsic compression, stenting has not been successful; this information is key to informed consent in a group of patients who may have a limited life expectancy.

Decision-making skills improve with critical care training: Using simulation to measure progress

PURPOSE

Health care professionals are expected to acquire decision-making skills during their training, but few methods are available to assess progress in acquiring these essential skills. The purpose of this study was to determine whether a simulation methodology could be used to assess whether decision-making skills improve during critical care training.

MATERIALS AND METHODS

Sixteen simulated scenarios were designed to assess a critical care provider's ability to make decisions in the care of a critical ill patient. Seventeen (17) critical care providers managed 8 of the scenarios early during their training and then managed a second set of 8 scenarios (T2) at the conclusion of their training.

RESULTS

Provider's mean global scenario scores (0-9) increased significantly fromT1 and T2 (5.64 ± 0.74) and (6.54 ± 0.64) with a large effect size (1.3). Acute care nurse practitioners and fellows achieved similar overall scores at the conclusion of their training (ACNP 6.43 ± 0.57; Fellows 6.64 ± 0.72).

CONCLUSIONS

These findings provide evidence to support the validity of a simulation-based method to assess progress in decision-making skills. A simulation methodology could be used to establish a performance standard that determined a provider's ability to make independent decisions.

The landscape of nonlinear structural dynamics: an introduction

Nonlinear behaviour is ever-present in vibrations and other dynamical motions of engineering structures. Manifestations of nonlinearity include amplitude-dependent natural frequencies, buzz, squeak and rattle, self-excited oscillation and non-repeatability. This article primarily serves as an extended introduction to a theme issue in which such nonlinear phenomena are highlighted through diverse case studies. More ambitiously though, there is another goal. Both the engineering context and the mathematical techniques that can be used to identify, analyse, control or exploit these phenomena in practice are placed in the context of a mind-map, which has been created through expert elicitation. This map, which is available in software through the electronic supplementary material, attempts to provide a practitioner's guide to what hitherto might seem like a vast and complex research landscape.

Outcomes of a proficiency-based skills curriculum at the beginning of the fourth year for senior medical students entering surgery

INTRODUCTION

We hypothesized that a proficiency-based curriculum administered early in the fourth year to senior medical students (MS4) would achieve outcomes comparable to a similar program administered during surgical internship.

METHODS

MS4 (n = 18) entering any surgical specialty enrolled in a proficiency-based skills curriculum at the beginning of the fourth year that included suturing/knot-tying, on-call problems, laparoscopic, and other skills (urinary catheter, sterile prep/drape, IV placement, informed consent, electrosurgical use). Assessment was at 4-12 weeks after training by a modified Objective Structured Assessment of Technical Skills (OSATS). Suturing and knot tying tasks were assessed by time and OSATS technical proficiency (TP) scores (1 [novice], 3 [proficient], 5 [expert]). Outcomes were compared with PGY-1 residents who received similar training at the beginning of internship and assessment 4-12 weeks later. Data are presented as mean values ± standard deviation; statistical significance was assessed by Student's t test.

RESULTS

Fifteen of 18 MS4 (83%) reached proficiency on all 15 tasks, and 2 others were proficient on all but 1 laparoscopic task. Compared with PGY-1s, MS4 were significantly faster for 3 of 5 suturing and tying tasks and total task time (547 ± 63 vs 637 ± 127 s; P < .05). Mean TP scores were similar for both groups (MS4, 3.4 ± 0.5 vs PGY-1, 3.1 ± .57; P = NS). MS4 OSATS scores were higher for IV placement, informed consent, and urinary catheter placement, but lower for prep and drape and for management of on-call problems.

CONCLUSION

MS4 who participate in a proficiency-based curriculum taught early in the fourth year are able to meet proficiency targets in a high percentage of cases. This approach should better prepare MS4 for surgical internship.

Retention of suturing and knot-tying skills in senior medical students after proficiency-based training: Results of a prospective, randomized trial

PURPOSE

We evaluated suturing skills performance and retention in senior medical students (MS4) at the beginning of their fourth year and 7 months later.

METHODS

MS4 students entering a surgery specialty were randomized to a proficiency-based suturing/knot-tying curriculum at the beginning of fourth year (Intervention, n = 11) versus no training (Control, n = 10). Time and technical proficiency (TP, proficiency ≥3) were assessed at baseline and 7 months. Performance was compared with past "Boot-Camp" MS4, categorical PGY-1 interns and PGY-2 residents. Data are mean ± SD.

RESULTS

At baseline, Intervention and Control MS4 had similar total task times (848 ± 199 vs 845 ± 209 seconds) and TP scores (1.8 ± 0.15 vs 1.8 ± 0.3). At 7 months, Intervention MS4 total task times were faster (549 ± 80 vs 719 ± 151 seconds, P < .01) and mean TP scores greater (3.3 ± 0.6 vs 2.1 vs 0.4, P < .001) than Control MS4. Intervention MS4 also performed better at 7 months than Boot-Camp MS4 (662 ± 171 seconds and 2.6 ± 0.5, P < .04) and were similar to PGY-1 interns (601 ± 74 seconds, TP 2.7 ± 0.7 seconds) and end of PGY-2 residents (475 ± 81 seconds and 3.6 ± 0.3 seconds).

CONCLUSION

A proficiency-based suturing and knot-tying curriculum taught early in the fourth year results in improved MS4 performance compared with no training or a traditional "boot camp" program.

Perceptual Thresholds for Acoustical Guitar Models

Synthesised acoustic guitar sounds based on a detailed physical model are used to provide input for psychoacoustical testing. Thresholds of perception are found for changes in the main parameters of the model. Using a three-alternative forced-choice procedure, just-noticeable diff erences are presented for changes in frequency and damping of the modes of the guitar body, and also for changes in the tension, bending stiff ness and damping parameters of the strings. These are compared with measured data on the range of variation of these parameters in a selection of guitars.

Video review using a reliable evaluation metric improves team function in high-fidelity simulated trauma resuscitation

OBJECTIVE

To demonstrate that instruction of proper team function can occur using high-fidelity simulated trauma resuscitation with video-assisted debriefing and that this process can be integrated rapidly into a standard general surgery curriculum.

DESIGN

The rater reliability of our team metric was assessed by having physicians and nonphysicians rate the same video-recorded trauma simulations at intervals in time. To assess the effectiveness of video debriefing, subjects participated in a 3-week trauma team training course that consisted of 2 video-recorded simulation sessions, each approximately 2 hours in length separated by a 90-minute debriefing session. To assess the impact of the debriefing session, video recordings of participants performing resuscitations before and after the debriefing were reviewed by a panel of blinded traumatologists and graded using our team evaluation instrument.

SETTING

The study took place at the high-fidelity simulation center at a large, urban academic training hospital.

PARTICIPANTS

All 11 PGY-2 general surgery and combined general surgery and plastic surgery residents at our institution.

RESULTS

Our instrument was found to have high interrater correlation (interclass correlation coefficient [ICC], 0.926; 95% confidence interval, 0.893-0.953). Initially, residents were either unsure as to their competency to serve as team leader (70%) or felt they were not competent to serve as team leader (30%). Ninety percent of residents found the video debriefing very to extremely helpful in improving team function and clinical competency. All participants felt more competent as both team leaders and team members because of the video debriefing. The mean team function score improved significantly after video debriefing (4.39 [±0.3] vs 5.45 [±0.4] prevideo vs postvideo review, p < 0.05).

CONCLUSIONS

Video review with debriefing is an effective means of teaching team competencies and improving team function in simulated trauma resuscitation. This strategy can be integrated readily into the surgical curriculum analogous to other applications of simulation technology.

Team behavior during trauma resuscitation: a simulation-based performance assessment

INTRODUCTION

Trauma resuscitations require a coordinated response from a diverse group of health care providers. Currently, there are no widely accepted methods of assessing team effectiveness in this setting. Simulation affords a method to assess team effectiveness. The purpose of this study was to use a simulation setting to develop a specialized assessment instrument for team response in trauma resuscitation.

METHODS

We developed our assessment instrument using clinical simulation. Four teams of 3 postgraduate year-2 surgical trainees in conjunction with scripted confederates were videotaped enacting 6 separate trauma resuscitation scenarios that mirrored clinical conditions encountered at our level 1 trauma center. Ten of the resulting videotaped scenarios represented a spectrum of team behavior (ineffective to effective) and were scored by 8 experienced clinicians using the Mayo High Performance Teamwork Scale.

RESULTS

Based in part on the Mayo High Performance Teamwork Scale, we created a prototype trauma team assessment tool consisting of 7 attributes that we scored in binary fashion (present/absent). We validated this prototype by assigning a normalized ranking score to each of the 10 scenarios based on the score supplied by each rater. The presence/absence of the 7 attributes varied significantly among scenarios (52.5% to 93.8%; P < .001). Median scores differed significantly comparing the 5 lowest-ranking scenarios with the 5 highest-ranking scenarios (P < .001).

CONCLUSION

Our prototype instrument may be effective at assessing team effectiveness during trauma resuscitations. This instrument may prove useful for assessing team competency skills, providing timely feedback to teams, and examining the relationship between effective team function and clinically important outcomes. Further, it may be applicable to other high-acuity, time-sensitive clinical situations.

Performance of Residents and Anesthesiologists in a Simulation-based Skill Assessment

Background

Anesthesiologists and anesthesia residents are expected to acquire and maintain skills to manage a wide range of acute intraoperative anesthetic events. The purpose of this study was to determine whether an inventory of simulated intraoperative scenarios provided a reliable and valid measure of anesthesia residents' and anesthesiologists' skill.

Methods

Twelve simulated acute intraoperative scenarios were designed to assess the performance of 64 residents and 35 anesthesiologists. The participants were divided into four groups based on their training and experience. There were 31 new CA-1, 12 advanced CA-1, and 22 CA-2/CA-3 residents as well as a group of 35 experienced anesthesiologists who participated in the assessment. Each participant managed a set of simulated events. The advanced CA-1 residents, CA-2/CA-3 residents, and 35 anesthesiologists managed 8 of 12 intraoperative simulation exercises. The 31 CA-1 residents each managed 3 intraoperative scenarios.

Results

The new CA-1 residents received lower scores on the simulated intraoperative events than the other groups of participants. The advanced CA-1 residents, CA-2/CA-3 residents, and anesthesiologists performed similarly on the overall assessment. There was a wide range of scores obtained by individuals in each group. A number of the exercises were difficult for the majority of participants to recognize and treat, but most events effectively discriminated among participants who achieved higher and lower overall scores.

Conclusion

This simulation-based assessment provided a valid method to distinguish the skills of more experienced anesthesia residents and anesthesiologists from residents in early training. The overall score provided a reliable measure of a participant's ability to recognize and manage simulated acute intraoperative events. Additional studies are needed to determine whether these simulation-based assessments are valid measures of clinical performance.

Multiple hyperechoic testicular lesions are a common finding on ultrasound in Cowden disease and represent lipomatosis of the testis

Cowden disease (CD) is a genetic disease associated with multiple hamartomas and malignant neoplasms. During investigations for possible subnormal fertility, a series of eight males with CD underwent ultrasound scanning of their testes. Our findings detail the seven adult patients that were found to have multiple and bilateral testicular lesions on ultrasound. These lesions in Cowden's patients represent a newly described testicular pathology - lipomatosis of the testis. Here we detail the radiological findings. Ultrasound findings showed multiple (estimated 40+) discreet lesions randomly scattered thoughout the parenchyma of each affected testis. The lesions themselves had heterogeneous echo texture, but all being hyperechoic and with a variable size from 1 mm to 6 mm. One patient underwent MR examination of the lesions in which a high T(1) signal was seen, but no useful characteristic features were identifiable.

Wave propagation in two-dimensional periodic lattices

Plane wave propagation in infinite two-dimensional periodic lattices is investigated using Floquet-Bloch principles. Frequency bandgaps and spatial filtering phenomena are examined in four representative planar lattice topologies: hexagonal honeycomb, Kagomé lattice, triangular honeycomb, and the square honeycomb. These topologies exhibit dramatic differences in their long-wavelength deformation properties. Long-wavelength asymptotes to the dispersion curves based on homogenization theory are in good agreement with the numerical results for each of the four lattices. The slenderness ratio of the constituent beams of the lattice (or relative density) has a significant influence on the band structure. The techniques developed in this work can be used to design lattices with a desired band structure. The observed spatial filtering effects due to anisotropy at high frequencies (short wavelengths) of wave propagation are consistent with the lattice symmetries.

Stress urinary incontinence: current understanding

Many new concepts were introduced in epidemiology, a etiopathology and treatment of stress urinary incontinence. This review gives a short account of these concepts and compares the results of commonly used treatment options with new ones recently introduced.

Stress urinary incontinence: current understanding

Many new concepts were introduced in epidemiology, a etiopathology and treatment of stress urinary incontinence. This review gives a short account of these concepts and compares the results of commonly used treatment options with new ones recently introduced.

Reliability and Validity of a Simulation-based Acute Care Skills Assessment for Medical Students and Residents

Background

Medical students and residents are expected to be able to manage a variety of critical events after training, but many of these individuals have limited clinical experiences in the diagnosis and treatment of these conditions. Life-sized mannequins that model critical events can be used to evaluate the skills required to manage and treat acute medical conditions. The purpose of this study was to develop and test simulation exercises and associated scoring methods that could be used to evaluate the acute care skills of final-year medical students and first-year residents.

Methods

The authors developed and tested 10 simulated acute care situations that clinical faculty at a major medical school expects graduating physicians to be able to recognize and treat at the conclusion of training. Forty medical students and residents participated in the evaluation of the exercises. Four faculty members scored the students/residents.

Results

The reliability of the simulation scores was moderate and was most strongly influenced by the choice and number of simulated encounters. The validity of the simulation scores was supported through comparisons of students'/residents' performances in relation to their clinical backgrounds and experience.

Conclusion

Acute care skills can be validly and reliably measured using a simulation technology. However, multiple simulated encounters, covering a broad domain, are needed to effectively and accurately estimate student/resident abilities in acute care settings.

An acute care skills evaluation for graduating medical students: a pilot study using clinical simulation

PURPOSE

This investigation aimed to explore the measurement properties of scores from a patient simulator exercise.

METHODS

Analytic and holistic scores were obtained for groups of medical students and residents. Item analysis techniques were used to explore the nature of specific examinee actions. Interrater reliability was calculated. Scores were contrasted for third year medical students, fourth year medical students and emergency department residents.

RESULTS

Interrater reliabilities for analytic and holistic scores were 0.92 and 0.81, respectively. Based on item analysis, proper timing and sequencing of actions discriminated between low- and high-ability examinees. In general, examinees with more advanced training obtained higher scores on the simulation exercise.

CONCLUSION

Reliable and valid measures of clinical performance can be obtained from a trauma simulation provided that care is taken in the development and scoring of the scenario.

Seismic observations of splitting of the mid-transition zone discontinuity in Earth's mantle

The transition zone of Earth's mantle is delineated by globally observed discontinuities in seismic properties at depths of about 410 and 660 kilometers. Here, we investigate the detailed structure between 410 and 660 kilometers depth, by making use of regional stacks of precursors to the SS phase. The previously observed discontinuity at about 520 kilometers depth is confirmed in many regions, but is found to be absent in others. There are a number of regions in which we find two discontinuities at about 500 and 560 kilometers depth, an effect which can be interpreted as a "splitting" of the 520 kilometer discontinuity. These observations provide seismic constraints on the sharpness and observability of mineralogical phase transitions in the mantle transition zone.

Reduced seizure threshold and hippocampal cell loss in rats exposed to alcohol during the brain growth spurt

BACKGROUND

Epilepsy is a prominent sign of neurologic dysfunction in some children with fetal alcohol syndrome (FAS). However, it is unknown whether the epileptic disorders in these children are directly due to the neuroteratogenic effects of alcohol or to some other factor accompanying maternal alcoholism. The hippocampus is vulnerable to alcohol-induced pathologic changes, and dysfunction of the hippocampus often manifests as epilepsy. We examined the effect of alcohol exposure during development on the seizure threshold and examined the relationship between alteration of seizure threshold and alcohol-induced neuronal loss from the hippocampus.

METHODS

Rat pups received 0.85, 2.5, or 3.75 g/kg of alcohol via intragastric intubation daily over postnatal days (PD) 4-9. An intubated control and a suckle control group were also included. To assess the effect of a single day of alcohol exposure, an additional group received 3.75 g/kg of alcohol on PD 4 alone. Behavioral seizure thresholds were determined by intravenous infusion of the proconvulsant, pentylenetetrazol (PTZ), on PD 31 or on PD 90. In addition, electrographic seizure thresholds were determined by recording extracellular field potentials from the dentate gyrus. The number of hippocampal CA1 pyramidal cells, CA3 pyramidal cells, and granule cells of the dentate gyrus were determined by stereology.

RESULTS

Daily exposure to alcohol resulted in a dose-dependent decrease in the seizure threshold and in the selective loss of CA1 pyramidal cells. Reduction in the seizure threshold was significantly correlated with loss of CA1 pyramidal cells. Recordings of extracellular field potentials confirmed the alcohol-induced reduction in seizure threshold, demonstrated that PTZ-induced seizures involve hippocampal-parahippocampal circuitry, and provided evidence that the hippocampal formation is the generator of the PTZ-induced seizures in alcohol-exposed animals.

CONCLUSIONS

These findings demonstrate that exposure of the developing brain to alcohol can permanently reduce the threshold for both behavioral and electrographic seizures and can selectively kill hippocampal CA1 pyramidal cells. Both the pathologic findings and the physiologic recordings support the concept that the reduced seizure threshold in alcohol-exposed animals is due to hippocampal pathology.

Reconstruction of bowing point friction force in a bowed string

A method is presented for reconstructing the friction force and the velocity at the bowing point of a string excited by a rosined bow sliding transverse to the string. Two versions of the method of reconstruction are presented, each approximate in different ways, but both capable of sufficient accuracy to allow useful application to problems of understanding frictional interactions in this dynamical system. The method is illustrated with simulated data to verify its accuracy, and results are shown for two contrasting cases of observed stick-slip string motion. As has been found in other investigations, the friction force during sliding is not determined by the instantaneous sliding speed. The results seem to be compatible with a thermally based model of rosin friction.

The management of occupational health by NHS Trusts in the north of England

This paper reports the findings of an audit of the management of occupational health arrangements in 36 NHS Trusts in the Northern and Yorkshire region of England. A questionnaire was designed based on a national NHS occupational health standard to obtain data on eight categories of occupational health activity: health and safety; pre-employment assessments; Infection Control; health surveillance; sickness absence; ill-health retirement; health promotion and record storage. The management arrangements for occupational health were varied. Assessments of workplace hazards, prevention of HIV-positive workers from performing exposure-prone invasive procedures and the assessment of pregnant workers were identified as issues for further consideration. Provision of competent and effective occupational health services will assist in the management of sickness absence and in the protection and promotion of health of staff. It will also contribute to the health and safety of patients.

Lessons from patient notification exercises following the identification of hepatitis B e antigen positive surgeons in an English health region

The results of hepatitis B virus (HBV) serology from notification exercises conducted in cohorts of patients exposed to three surgeons positive for hepatitis B e antigen (HBeAg) identified in one English health region in 1994 and 1995 were reviewed. Of 777 patients notified, serology results at six months or more after exposure were available for 514 individuals who had not received post exposure prophylaxis. In one case DNA analysis confirmed transmission of HBV from surgeon to patient. Pre-existing natural immunity to HBV was found in a further 19 patients, none of whom had evidence of recent infection, and in 13 patients (classified as cases of undetermined origin) transmission during surgery could not be excluded. The overall estimated transmission rate was 0.2% for confirmed cases (95% confidence interval (CI) 0.004-1.1) and 2.7% (95% CI 1.5-4.5) if cases of undetermined origin were included. The management of recall exercises should consider the risks of the operative procedures performed and the time that has elapsed since exposure.

The transient behaviour of models of bowed-string motion

Theoretical models of the action of a bowed string may be able to shed light on differences of "playability" between different violins. Subjective judgements seem to be concerned, at least in part, with the robustness with which one particular oscillation regime of the string (the "Helmholtz motion") may be obtained under different bowing conditions. In this paper, after a review of bowed-string modelling, systematic simulation is used to obtain plots of the basin of attraction of the Helmholtz motion in a particular subspace of the player's control space. Variations in the size and structure of this basin of attraction are seen when parameters of the problem are varied, and some physical interpretation of these variations is given. Some parallels and contrasts are pointed out between the particular features of the bowed string as a nonlinear system, and the range of more familiar dynamical systems. (c) 1995 American Institute of Physics.

Asthma and factory emissions in northern England: addressing public concern by combining geographical and epidemiological methods

STUDY OBJECTIVE

The prevalence of asthma was assessed to investigate respiratory health effects of airborne emissions from a factory. A geographical information system allowed flexible definition of study areas in terms of their size, distance, and location in relation to the factory. The value of the approach for this type of investigation is focussed on.

SETTING

The factory is located in the south western part of a small market town in County Durham.

MEASUREMENTS AND MAIN RESULTS

A total of 1573 asthma cases were identified from general practitioner computerised repeat prescribing systems. Population denominators were defined from family health services authority patient registers. The area within 1 km and immediately to the north east of the factory had an age and sex standardised asthma prevalence 24% (confidence interval 4, 44%) in excess of the expected rate (p = 0.01). The increased prevalence was confined to middle aged and elderly adults living in the area between 0.5 and 1 km to the north east of the factory.

CONCLUSIONS

The value of combining the skills of geographers and epidemiologists in addressing public health issues is shown, particularly through the use of geographical information systems which proved powerful and effective.