Why I Teach

Professor Stephen Bricher explains why he teaches

Theoretical Framework for the Study of Genetic Diseases Caused by Dominant Alleles

We propose a theoretical basis for analyzing several features of genetic diseases caused by dominant alleles, including: disease prevalence, genotype penetrance, and the relationship between causal genotype frequency and disease frequency. In addition, we provide a theoretical framework for accurate diagnosis and clinical approaches for disease study, including two examples in which inaccurate and incomplete diagnoses affect the estimates of disease prevalence: First, the disease iceberg effect shows that disease prevalence is often underestimated due to errors introduced by inaccurate diagnosis; second, because lifetime risk of disease is cumulative, and therefore an increasing function of age, measurements of prevalence are inaccurate if people of all ages are not included. Finally, we discuss the aggregation of genetic diseases. We identify theoretical and computational deficiencies associated with using the sibling recurrence-risk ratio as a measure of familial aggregation. We develop an alternative concept of aggregation and propose an associated measure that does not experience the deficiencies. Throughout, we provide clinicians and researchers practical implications of our theoretical framework

Modeling the Disappearance of the Neanderthals Using Concepts of Population Dynamics and Ecology

Current hypotheses regarding the disappearance of Neanderthals (NEA) in Europe fall into two main categories: climate change, and competition. Here we review current research and existing mathematical models that deal with this question, and we propose an approach that incorporates and permits the investigation of the current hypotheses. We have developed a set of differential equations that model population dynamics of anatomically modern humans (AMH) and NEA, their ecological relations to prey species, and their mutual interactions. The model allows investigators to explore each of the two main categories or combinations of both, as well as various forms of competition and/or interference within the context of competition. The model is designed to include a wide variety of hypotheses and associated archaeological evidence, not focused on a particular hypothesis regarding NEA extinction. It therefore provides investigators with a model to impartially examine various hypotheses (individually or in combination) regarding climatic effects, differential resource use, differences in birth/death rates and carrying capacities, competition, interference, disease, interbreeding, and cultural distinctions that might have led to the extinction of NEA. Moreover, the model accommodates the design of scenarios concerning—for example—population growth, hunting, competitive interactions, cultural differences, and climatic influences to investigate which concepts best explain the rapid disappearance of NEA. In addition, our model is a modification of the classical Lotka-Volterra model for a wide range of any two populations competing for a common resource. Specifically, our model explicitly includes the resource as an additional variable, a dependence of important population parameters on resource, as well as accommodates treating one of the populations as invasive

Holding and restraining children for clinical procedures within an acute care setting: an ethical consideration of the evidence

This critical reflection on the ethical concerns of current practice is underpinned by a systematic synthesis of current evidence focusing on why and how children are held or restrained for clinical procedures within acute care and the experiences of those present when a child is held against their wishes. Empirical evidence from a range of clinical settings internationally demonstrates that frequently children are held for procedures to be completed; younger children and those requiring procedures perceived as urgent are more likely to be held. Parents and health professionals express how holding children for procedures can cause feelings of moral distress expressed as uncertainty, guilt and upset and that this act breaches the trusting and protective relationship established with children. Despite this, children’s rights and alternatives to holding are not always respected or explored. Children’s experiences and perceptions are absent from current literature. Children and young people have a moral right to have their voice and protests heard and respected and for these to inform judgements of their best interests and the actions of health professionals. Without robust evidence, debate and recognition that children are frequently held against their wishes in clinical practice for procedures which may not be urgent, children’s rights will continue to be compromised