This research identifies realistic timelines for human survivability during accidental dwelling fires (ADF). It also establishes a time window within which the fire service is likely to affect a rescue of the occupants from ADFs. Through a comparison of these two timelines, the likelihood that the fire service will rescue an occupant before they receive a fatal dose of heat and/or smoke (asphyxiant gases) is established. The dependence of fire service intervention times is also assessed in the context of increasing intervention times resulting from cuts to fire authority budgets. The results show that an increase in the time taken to affect a rescue will lead to an increase in the number of fatalities and the severity of injuries which occur when the occupants of a dwelling become trapped by (or are otherwise unable to escape from) fire within the property. Around 80% of all fire deaths and injuries in Great Britain occur in dwellings. This study analyses national and local fire statistics to identify the typical fire situations and common circumstances which lead to fire deaths and injuries. This statistical analysis has been used to inform the carrying out of thirteen large-scale fire experiments. Asphyxiant gas concentrations and compartment temperatures were gathered during these experiments, in order to establish human survival times resulting from the adverse effects of exposure to these. Statistics have also been analysed and a methodology developed to establish fire service intervention times. Establishing survival times on the basis of an analysis of national statistics constitutes new work within the field of community fire safety. In addition, the author is in a preferential position to establish realistic times for fire service interventions, and there is no evidence that these timelines have previously been developed to this extent or compared to timelines for occupant survival. The findings of this research should be considered by fire authorities as they make important decisions for the development of local fire service resourcing activities in continuing times of austerity.

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Patient safety has been on the research agenda since 2000, when unnecessary harm to patients in providers’ care came to light. In 2005, the improvements in patient safety fell short of expectations, and the patient safety research community recognized that the issues are more difficult to resolve than first thought. One of the tools to address this vexing problem has been voluntary incident reporting systems, although the literature has given incident reporting systems mixed reviews. This qualitative comparative case study comprises 85 semi-structured interviews in two separate divisions of a tertiary care hospital, General Internal Medicine (GIM) and Obstetrics and Neonatology (OBS/NEO). The main line of questioning concerned incident reporting; general views of patient safety were also sought. This is a thesis by publication. The thesis consists of a general introduction to patient safety, a literature review, a description of the methods and cases, followed by the manuscripts. The thesis concludes with a summarization of the findings, and implications of the study. Manuscript one focuses on the reporter end of incident reporting systems. It asks what frames underlie GIM nurse and physician self reporting and peer reporting practices. The findings showed that frames that inhibit reporting are shared by physicians and nurses, such as the fear of blame frame regarding self reporting, and the tattletale frame regarding peer reporting. These frames are underpinned by a focus on the individual, despite the organisational message of reporting for learning. A learning frame is an enabler to incident reporting. Viewing the objective of voluntary incident reporting as learning allows practitioners to depersonalize incident reporting. The focus becomes preventing recurrence and not the individual reporting or reported on. Manuscript two again focuses on the reporter end, and on one type of reportable incident – a problem that healthcare practitioners can fix themselves. The study asks: when faced with such a problem, do practitioners fix it in the moment and forget about it, or do they fix it in the moment and report it? We found that “fixing and forgetting” was the main choice that most GIM practitioners made in situations where they faced problems that they themselves could resolve. These situations included a) handling near misses, which were seen as unworthy of reporting since they did not result in actual harm to the patient, b) prioritizing solving individual patients’ safety problems, which were viewed as unique or one-time events, and c) encountering re-occurring safety problems, which were framed as inevitable, routine events. The paper argues that fixing and forgetting patient safety problems encountered may not serve patient safety as well as fixing and reporting. The latter approach aligns with a preventive view of patient safety. Manuscript three focuses on the practice of double checking, drawing from interviews conducted in both GIM and OBS/NEO. It asks what weaknesses are in the double checking process and what alternative views can help the double checking process enhance patient safety. The findings showed weaknesses in the double checking process, such as: a) double checking trusted as an independent process, b) double (or more) checking as a costly and time consuming procedure, and c) double checking as preventing reporting of near misses. It is proposed that there are alternative ways of viewing and practising double checking in order to enhance patient safety. These include: a) recognizing that double checking requires training, b) introducing automated double checking, and c) expanding double checking beyond error detection. The paper argues that practitioners need to be more aware of the caveats of double checking, and to view the double checking process through alternate lenses to help enhance its effectiveness. Manuscript four focuses on the reporting system more comprehensively, and attends to the reporting process in GIM and OBS/NEO. This is a comparative case study of the two divisions, and considers the different stages in the process and the factors that help shape the process. The findings showed that there were major differences between the two divisions in terms of: a) what comprised a typical report (outcome based vs communication and near-miss based); b) how the reports were investigated (individual manager vs interdisciplinary team); c) learning from reporting (interventions having ambiguous linkages to the reporting system vs interventions having clear linkages to reported incidents); and d) feedback (limited feedback vs multiple feedback). The differences between the two divisions can be explained in terms of: a) the influence of litigation on practice, b) the availability or lack of interprofessional training, and c) the introduction of the reporting system (top-down vs bottom-up approach). A model based on the findings portraying the influences on incident reporting and learning is provided. This thesis contributes to an in-depth understanding of front line perspectives on incident reporting systems and safety, and aims to provide insights into improving patient safety. Implications for practice and research will be addressed.

This thesis reports three experiments investigating how age-related declines in visual motion processing affect older drivers’ ability to drive safely. In particular, these experiments assess the efficacy of: 1) A test of motion sensitivity, the Peripheral Motion Contrast Threshold (PMCT) test, which evaluates ones’ contrast threshold for detecting motion in the periphery, and 2) the 3D multiple-object tracking test (3D MOT), which evaluates the maximum stimulus speed at which one can maintain visual attention on several objects moving in three dimensions. Two versions of the PMCT test—the PMCT-10 and the shorter PMCT-2—were employed. Driving safety was measured via a high fidelity driving simulator, in addition to several self-report measures and archival data. Study 1 showed that PMCT-2 and PMCT-10 thresholds were associated with number of crashes in the simulator and other indices of unsafe driving. Study 2 examined whether the PMCT-2 could predict older driver performance during a different set of simulated driving scenarios, and whether it was associated retrospectively with real world crash rates. PMCT-2 results were significantly correlated with simulated crash risk. Moreover, Study 2 provided the first evidence that PMCT scores are associated with real-world crash, albeit in a small retrospective sample. Study 3 examined the relationship between results from both the PMCT-2 and 3D MOT tests and simulated driving. Multiple object tracking has previously been associated with older drivers' performance. Results showed a strong relationship in our sample between crash rates and 3D MOT results. However, we failed to replicate the results showing a relationship between PMCT and crash occurrence. This may have been due to high rates of subject attrition due to simulator sickness, which resulted in a small final sample. Overall, findings from the three studies demonstrate that results from PMCT and 3D MOT are associated with older drivers’ performance measures, such as crash rates, dangerous lane deviations, and speeding. These findings support visual motion processing measures as viable candidates for inclusion in a multi-domain assessment of older drivers’ fitness to drive.

The dynamics of the intrinsically unstable premixed flames propagating in channels is studied by means of numerical modelling in this work. Critical conditions of extinction and the influence of the thermal-diffusive effect on the dynamics of flame propagating in planar channels with cold sidewalls under gravity is investigated. For the horizontally propagating flames, the appearance of inversion influences the effect of thermal-diffusion on the asymmetry of flame fronts. For upwards propagating flames, the convex shape of the flame imposed by the mode of ignition combined with buoyancy can suppress the thermal-diffusive effects; in contrast, the buoyancy alone cannot damp the thermal diffusive effects even for quite large Froud numbers in regard to the appearance of inversion. The variation of Lewis number has no essential effect on the planar flame shape formation when flame propagates downward. Lowering Lewis number can significantly decrease the critical conditions of extinction. However, if Lewis number is smaller than some limit, its further effect on the critical extinction conditions is unsignificant. In the two-step consecutive reaction, the effects of the ratio of Damkohler numbers, heat release rates, activation energy and Lewis number on the separation and fragmentation of flames are considered. The inversion is more pronounced in combustion with separated flame fronts than for single-step reactions. However, the inversion is obvious only when the two flame fronts are close enough to each other. Thus, the details of combusiiition chemistry may have a strong effect on the stability of the flame front. The thermal diffusive effect of the first flame is, in certain way, dominant and has influence on the second flame. The presence of the first reaction suppresses the thermal-diffusive effect of the second reaction in regard to the appearance of inversion. The propagation of flames at a variety of Reynolds number ranging from 70 to 1000 are explored. For longer channels or a flat initial flame front, the inversion of the flame is apparent for Reynolds number higher than 200. For large &, the computational grids should be very fine because of the small thickness of preheat zone. The Generalized Curvilinear Coordinate Gridding method is introduced and an elliptic grid generator based on the variational approach is employed to construct the solution-adaptive grids. However, we found out that the global structure of the algorithm required by the adaptive grid approach might be not as efficient as simplified non-adaptive grids for prospective use of massively parallel computers.

Despite the known health hazards associated with exposure to lead, occupational lead poisoning remains a health problem. Although a variety of public health programs have been implemented to control this exposure, knowledge of which occupational groups are at greatest risk is incomplete. This research developed and applied a lead risk model that generated estimates of lead-using industries and numbers of employees potentially exposed to lead, and then, validated the model through a lead exposure prevalence survey among construction workers. The lead risk model was developed using data from the National Occupational Exposure Survey, state lead registries, lead inspection results from the Occupational Safety and Health Administration, and other sources. The model was applied to Massachusetts County Business Patterns and Department of Employment and Training databases to produce state and county estimates of numbers of employees potentially exposed to lead, and lead-using companies, ranked by exposure risk. The sensitivity of the state lead registry was evaluated using estimates from this model. To validate the model, a prevalence survey of lead exposure was conducted among a sample of 127 western Massachusetts plumbers. Based on the model, an estimated 1% (20,825) of Massachusetts employees are potentially exposed to lead, 53% are at moderate or high risk of lead exposure, and 74% work within a 5 contiguous-county area in eastern Massachusetts. There are 3,448 lead-using facilities, representing 2% of total companies. The model also showed a high sensitivity (70%) for state regulated construction groups within the lead registry, but low sensitivities for all other construction industries. The geometric mean for blood lead and zinc protoporphyrin among plumbers in the prevalence survey were 7.0 $\mu$g/dl and 30.9 $\mu$g/dl, respectively, indicating relatively low levels of lead exposure. Current smokers, smoking at the workplace, and hand scraping metal were associated with higher lead levels, while wearing protective equipment at work was associated with lower levels. The model identified non-traditional lead-using industries, thus, potentially allowing the state to better target educational and medical intervention activities to reduce the risk of occupational lead exposure. Similar lead-reduction activities can be applied to other states that adopt the model.

Injury epidemiology, a relatively new sub-discipline of epidemiology, has continued to evolve since the ground-breaking work by Dr. William Haddon during the 1960s. The case-crossover design is a relatively new epidemiological methodology developed specifically for investigating the transient effects of a brief exposure on the onset of an acute outcome. This dissertation work provides some initial empirical data illustrating the strengths and limitations of the case-crossover design as applied within the field of occupational injury epidemiology. The review of the literature details the utility of the case-crossover study design, the currently known strengths and limitations, and confirms the under-utilization of this design to date. Examples from an on-going multi-center, interview-based, case-crossover study of acute traumatic occupational hand injuries are utilized to highlight some of the strengths and weaknesses of this new method, as applied to injury research. The application demonstrates the importance of temporal factors in determining the etiology of occupational acute traumatic hand injury. The findings point out the need to know more about the timing of high risk work tasks and transient exposures throughout the work day. These factors should be taken into consideration when developing intervention strategies for the prevention of hand injuries in the workplace. To evaluate the potential impact of information bias on the results of this study, a reliability study was also conducted. The findings from this test-retest study suggest that the frequency and duration of unusual transient workplace exposures, occurring proximal to the time of an injury, can be reliably recalled using a telephone interview.

Enhancing our understanding of the relation that exists between productivity and musculoskeletal disorders is essential to the successful design of person-machine systems for safe and comfortable human use. This research comprises two experiments to study the trade-offs between productivity and shoulder musculoskeletal discomfort in a repetitive task performed at different repetition rates. The objective of the first experiment was to determine from velocity profiles which theoretical movement time model adequately predicted the times for a mail sorting task. Based on the percentage of the total variance explained by the regression models, it was concluded that the optimized initial impulse model (Meyer et al., 1988) using one sub-movement provided the best prediction for the movement times associated with the repetitive task. In addition, the effects of different duty cycles upon movement time were studied. It was found that a decrease in repetition rate produced an increase in mean movement time. In the second experiment a regression model that related biodemographic, anthropometric, workplace and kinematic factors to shoulder musculoskeletal discomfort was developed. Also, the effects of these ergonomic factors upon shoulder musculoskeletal discomfort were studied. It was found that the kinematic variables played the most important role in increasing the percentage of the total variance explained by the regression model. Results showed a significant linear relationship between weight and shoulder musculoskeletal discomfort. High weight values were associated with higher discomfort scores. To diminish the discomfort values it was recommended the improvement of the worker-machine system by designing adjustable equipment within the capabilities of the people to optimize their performance at work. The associations between (1) the number of repetitions, (2) movement time and (3) shoulder musculoskeletal discomfort were studied. It was determined that, if the anthropometry of the working population is considered, an adjustment point for the movement time could be identified (which determines the productivity level of the workers) and a better design of a repetitive task could be achieved. Finally regarding the discomfort-productivity trade-off evaluation, it was found that higher SMD scores were associated with longer movement time values regardless of the experimental population percentile.