CIEGEN: A system for testing knowledge base compilation heuristics on a microcomputer

The expert system has proven itself to be a valuable aid in diagnosing and treating problems in domains requiring expertise. The commercial world has been alerted to this fact and the thrust is to make the expert system portable and available on small computers. The goal of this research has been to lay the groundwork for a domain independent expert system builder on a microcomputer. The result of this effort was CIEGEN, a system consisting of a rule compiler, inference engine, and rule generator developed on the IBM PC. It is domain independent, responsible for transforming a knowledge base of rules into heuristic based decision trees, and capable of performing backward chaining consultations. The system is also heuristic independent, allowing a knowledge base to be compiled by different heuristics and compared using the log created by the inference engine. A subgoal of the development of CIEGEN has been to study the heuristics used to compile a knowledge base because the efficiency of the expert system is based on the intelligence of the heuristic. The heuristic used by EMYCIN was implemented and compared with a heuristic developed by the author. For the six types of knowledge based generated by CIEGEN\u27s rule generator, EMYCIN\u27s heuristic, on the average, executed more quickly --Abstract, page ii

Trends shaping Africa's agricultural landscape

International audienc

The quiet rise of medium-scale farms in Malawi

Medium-scale farms have become a major force in Malawi's agricultural sector. Malawi's most recent official agricultural survey indicates that these account for over a quarter of all land under cultivation in Malawi. This study explores the causes and multifaceted consequences of the rising importance of medium-scale farms in Malawi. We identify the characteristics and pathways of entry into farming based on surveys of 300 medium-scale farmers undertaken in 2014 in the districts of Mchinji, Kasungu and Lilongwe. The area of land acquired by medium-scale farmers in these three districts is found to have almost doubled between 2000 and 2015. Just over half of the medium-scale farmers represent cases of successful expansion out of small-scale farming status; the other significant proportion of medium-scale farmers are found to be urban-based professionals, entrepreneurs and/or civil servants who acquired land, some very recently, and started farming in mid-life. We also find that a significant portion of the land acquired by medium-scale farmers was utilized by others prior to acquisition, that most of the acquired land was under customary tenure, and that the current owners were often successful in transferring the ownership structure of the acquired land to a long-term leaseholding with a title deed. The study finds that, instead of just strong endogenous growth of small-scale famers as a route for the emergence of medium-scale farms, significant farm consolidation is occurring through land acquisitions, often by urban-based people. The effects of farmland acquisitions by domestic investors on the country's primary development goals, such as food security, poverty reduction and employment, are not yet clear, though some trends appear to be emerging. We consider future research questions that may more fully shed light on the implications of policies that would continue to promote land acquisitions by medium-scale farms. (Résumé d'auteur

Evolutionary analysis of rapidly evolving RNA viruses

Recent advances in sequencing technology and computing power mean that we are in an unprecedented position to analyse large viral sequence datasets using state-of-the-art methods, with the aim of better understanding pathogen evolution and epidemiology. This thesis concerns the evolutionary analysis of rapidly evolving RNA viruses, with a focus on avian influenza and the use of Bayesian methodologies which account for uncertainty in the evolutionary process. As avian influenza viruses present an epidemiological and economic threat on a global scale, knowledge of how they are circulating and evolving is of substantial public health importance. In the first part of this thesis I consider avian influenza viruses of haemagglutinin (HA) subtype H7 which, along with H5, is the only subtype for which highly pathogenic influenza has been found. I conduct a comprehensive phylogenetic analysis of available H7 HA sequences to reveal global evolutionary relationships, which can help to target influenza surveillance in birds and facilitate the early detection of potential pandemic strains. I provide evidence for the continued distinction between American and Eurasian sequences, and suggest that the most likely route for the introduction of highly pathogenic H5N1 avian influenza to North America would be through the smuggling of caged birds. I proceed to apply novel methods to better understand the evolution of avian influenza. Firstly, I use an extension of stochastic mutational mapping methods to estimate the dN/dS ratio of H7 HA on different neuraminidase (NA) subtype backgrounds. I find dN/dS to be higher on the N2 NA background than on N1, N3 or N7 NA backgrounds, due to differences in selective pressure. Secondly, I investigate reassortment, which generates novel influenza strains and precedes human influenza pandemics. The rate at which reassortment occurs has been difficult to assess, and I take a novel approach to quantifying reassortment across phylogenies using discrete trait mapping methods. I also use discrete trait mapping to investigate inter-subtype recombination in early HIV-1 in Kinshasa, the epicentre of the HIV-1 group M epidemic. In the final section of the thesis, I describe a method whereby epidemiological parameters may be inferred from viral sequence data isolated from different infected individuals in a population. To conclude, I discuss the findings of this thesis in the context of other evolutionary and epidemiological studies, suggest future directions for avian influenza research and highlight scenarios in which the methods described in this thesis might find further application

Reddening the hearts and minds: The frontier myth and American identity in Vietnam War literature.

I provide many examples from films and novels to illustrate a pattern resulting from the Vietnam War's threat to the frontier myth. The frontier myth is re-established in Vietnam War literature through a roughly chronological progression taking the American soldier from identification with the cowboy stereotype at the war's outset to an Indian stereotype in the war's aftermath. When the United States lost the Vietnam War, American cultural identity was threatened. The notion of losing a military engagement was not reconcilable with the providential view of history and the frontier myth. Cultural constructions were needed which could situate Vietnam veterans without demolishing these fundamentally important cultural notions. Thus, defeated American veterans are depicted as Native Americans.Ramifications of the "reddening" of Vietnam War veterans are revealed in Philip Caputo's Indian Country as Christian Starkmann's growth is metaphorically linked with competing images of cowboy-ness and Indian-ness. That novel shows how a specific character celebrates an "othered" status as he recognizes the way he has been situated by the frontier myth and the American experience of the Vietnam War. Textual associations of Native Americans with Vietnam War veterans reveals a long-lasting and perhaps inescapable history of racism, but they also reveal a powerful ability of literary veterans to undergo both metaphorical and actual shifts in identity when they recognize the work of the frontier myth in American culture.Vietnam War literature reveals much about American identity, culture, history, and myth. I examine novels by Philip Caputo, Tim O'Brien, and Michael Herr to analyze ways war myths and myths of the American frontier are invoked and altered in Vietnam War literature. These novels dispel myths by revealing them to be ineffective in making sense of the narrators' experiences. In the process of debunking these myths, the narrators show that the war did not make sense. As a result, a new type of myth emerges which states that the only sense to be made of the Vietnam War is that it was an anomaly. Thus, Vietnam War literature creates an anti-myth that allows for the continuation of cultural adherence to the frontier myth

CIEGEN: A System for Testing Knowledge Base Compilation Heuristics on a Microcomputer

The expert system has proven itself to be a valuable aid in diagnosing and treating problems in domains requiring expertise. The commercial world has been alerted to this fact and the thrust is to make the expert system portable and available on small computers. The goal of this research has been to lay the groundwork for a domain independent expert system builder on a microcomputer. The result of this effort was CIEGEN, a system consisting of a rule compiler, inference engine, and rule generator developed on the IBM PC. It is domain independent, responsible for transforming a knowledge base of rules into heuristic based decision trees, and capable of performing backward chaining consultations. The system is also heuristic independent, allowing a knowledge base to be compiled by different heuristics and compared using the log created by the inference engine. A subgoal of the development of CIEGEN has been to study the heuristics used to compile a knowledge base because the efficiency of the expert system is based on the intelligence of the heuristic. The heuristic used by EMYCIN was implemented and compared with a heuristic developed by the author. For the six types of knowledge based generated by CIEGEN\u27s rule generator, EMYCIN\u27s heuristic, on the average, executed more quickly

Effects of glaucoma and snoring on cerebral oxygenation in the visual cortex: a study using functional Near Infrared Spectroscopy (fNIRS)

Purpose: The purpose of this study was to investigate the effects of snoring and glaucoma on the visual Haemodynamic Response (HDR) using functional Near Infrared Spectroscopy (fNIRS). Methods: We recruited 8 glaucoma patients (aged 56-79), 6 habitual snorers (aged 26-61) and 10 healthy control participants (aged 21-78). Glaucoma patients were of varying subtypes and under care of ophthalmologists. Prior to testing visual acuity, blood pressure, heart rate and a medical history were taken. HDRs were recorded over the primary visual cortex (V1) using a reversing checkerboard paradigm. Results & Discussion: All participants showed the characteristic increase of Oxyhaemoglobin concentration ([HbO]) and decrease of Deoxyhaemoglobin concentration ([HbR]) during visual stimulation (p < 0.001, η2 = 0.78). Despite this, there were signifi cant group differences with a large effect size (η2 = 0.28). During visual stimulation normal participants had greater [HbO] compared to snorers and glaucoma patients (p < 0.01). Both glaucoma patients and snorers presented with comparable HDR for [HbO] and [HbR] in V1. Importantly, during visual stimulation, the increased [HbO] in glaucoma patients correlated well with their visual fi elds and self-reported activities of daily living (r = -0.98, r = -0.82, p < 0.05). Both glaucoma patients and snorers presented with an attenuated HDR in V1. Our results suggest a possible vascular link between these conditions

The Clinical Teaching Fellow role:exploring expectations and experiences

BackgroundMany UK junior doctors are now taking a year out of the traditional training pathway, usually before specialty training, and some choose to work as a clinical teaching fellow (CTF). CTFs primarily have responsibility for delivering hospital-based teaching to undergraduate medical students. Only a very small amount of literature is available regarding CTF posts, none of which has explored why doctors choose to undertake the role and their expectations of the job. This study aimed to explore the expectations and experiences of CTFs employed at NHS hospital Trusts in the West Midlands.MethodsCTFs working in Trusts in the West Midlands region registered as students on the Education for Healthcare Professionals Post Graduate Certificate course at the University of Birmingham in August 2019 took part in a survey and a focus group.ResultsTwenty-eight CTFs participated in the survey and ten participated in the focus group. In the survey, participants reported choosing a CTF role due to an interest in teaching, wanting time out of training, and being unsure of which specialty to choose. Expectations for the year in post were directly related to reasons for choosing the role with participants expecting to develop teaching skills, and have a break from usual clinical work and rotations. The focus group identified five main themes relating to experiences starting their job, time pressures and challenges faced in post, how CTF jobs differed between Trusts, and future career plans. Broadly, participants reported enjoying their year in a post at a mid-year point but identified particular challenges such as difficulties in starting the role and facing time pressures in their day-to-day work.ConclusionThis study has provided a valuable insight into the CTF role and why doctors choose a CTF post and some of the challenges experienced, adding to the sparse amount of literature. Understanding post holders’ experiences may contribute to optimisation of the role. Those employing CTFs should consider ensuring a formal handover process is in place between outgoing and incoming CTFs, having a lead person at their Trust responsible for evaluating changes suggested by CTFs, and the balance of contractual duties and personal development time

A systematic review of the diagnostic and prognostic value of urinary protein biomarkers in urothelial bladder cancer

For over 80 years, cystoscopy has remained the gold-standard for detecting tumours of the urinary bladder. Since bladder tumours have a tendency to recur and progress, many patients are subjected to repeated cystoscopies during long-term surveillance, with the procedure being both unpleasant for the patient and expensive for healthcare providers. The identification and validation of bladder tumour specific molecular markers in urine could enable tumour detection and reduce reliance on cystoscopy, and numerous classes of biomarkers have been studied. Proteins represent the most intensively studied class of biomolecule in this setting. As an aid to researchers searching for better urinary biomarkers, we report a comprehensive systematic review of the literature and a searchable database of proteins that have been investigated to date. Our objective was to classify these proteins as: 1) those with robustly characterised sensitivity and specificity for bladder cancer detection; 2) those that show potential but further investigation is required; 3) those unlikely to warrant further investigation; and 4) those investigated as prognostic markers. This work should help to prioritise certain biomarkers for rigorous validation, whilst preventing wasted effort on proteins that have shown no association whatsoever with the disease, or only modest biomarker performance despite large-scale efforts at validation