MS

thesisThe presence of change in basal body temperature (BBT) before onset of labor was tested by analyzing BBT charts. Wight-two women agreed to participate and were instructed in the proper measurement and recording of oral BBTs during the last five weeks of pregnancy. Comments were recorded daily for any factors affecting BBT existed. The data analysis was done on all valid charts returned, (25 of 28). Eight of the 25 charts showed isolated BBTs that dropped significantly (< 0.5° F) below the baseline, bur no pattern linked those charts. CUSM analysis showed no significant drop in the baseline BBT at any time during the final 21 days before labor. The findings suggest that BBT can not be used as a predictor of onset of labor in humans

The role of biodiversity on pest control ecosystem services in UK apple orchards

In this thesis I assess the ability of biodiversity to provide a functioning pest control ecosystem service to control moth pest species in UK apple orchards. I assess the ability of four types of farm management: organic, Linking Environment and Farming (LEAF), integrated pest management (IPM) and conventional, to measure the ability of pest predation from birds, and the impact that predation has on apple yields. I firstly describe the history and the landscape of the study area, an overview of the methods used and the farming systems that the field study and experiments took place on in Chapter 2. In Chapter 3 I assess farmland biodiversity by monitoring birds and butterflies as indicator species of biodiversity, to understand if farm management impacts biodiversity levels. Biodiversity was highest on organic orchards, which supports the plethora of studies in the literature. Using this information of biodiversity levels on orchard management types, in Chapter 4 I investigate whether this biodiversity supports a pest control service, and to a natural pest control service compares to a synthetic alternate used on non-organic orchards, through using a sentinel prey experiment in field. Pest control services were greater on organic farms, and followed the same patterns as insectivorous bird abundance, species richness, diversity, and density. This chapter also compares moth pest levels to understand the pest pressures across farms, which harbour different pest control strategies and showed that moth pest levels were broadly similar across all farm management types. Finally, in Chapter 5 I compare the farm management options available to famers, both the natural pest control system and the synthetic control system, using economic valuation methods. Although a natural pest control service from birds is present on organic orchards (Chapter 4), the yield per hectare increased significantly on non-organic orchards (expect LEAF) but is found to be in-different to yield value per hectare of organic orchards in variable scenarios. Importantly, the synthetic alternative to a pest control service available from wild insectivorous birds was found to be an insignificant farm management variable that impacts apple yield and yield value on non-organic orchards

Traumatic posterior fracture-dislocation of the hip joint in adults

During the period July 1994 to September 1998 surgery was carried out on seventy-six hips in seventy-five patients that sustained posterior fracture-dislocation of their hip joints. During my training I was personally involved in thirteen of these cases and was the primary surgeon in seven cases. Because of my personal interest in these patients Dr Siboto provided me the records of all seventy-five patients for my scrutiny. While he has carried out the surgery on all but the seven cases which I operated on, the literature review, the correlating of the data and all of the interpretation is my own personal work. At surgery prospective records were kept of the degree of comminution of the fracture, the presence of marginal impacting and the presence of fragments in the joint. Fractures were then classified according to Thompson and Epstein (1951). The surgical time was recorded as well as the nature of the associated acetabular floor fracture when it occurred. Anatomical reconstruction was always attempted including elevation of marginal impaction and bone grafting where appropriate. Fragments were only discarded when too small and unattached to permit their inclusion in the reconstruction. All patients had neurological assessment preoperatively and their Sciatic nerves were explored and the state of the nerve recorded at surgery. The process of formulating this dissertation took place over a two-year period from September of 1997 until June of 1999. As a result, the number of patients examined in relationship to a specific subject is not constant but alters according to the group under scrutiny at that particular point in time. An initial review of sixty cases in September 1997 was carried out and then an additional fifteen patients up until September 1998 were included where relevant. The aim of carrying out this study was to gain a better understanding of this injury so that we could formulate a management protocol for our patients in Groote Schuur Hospital. First of all, I reviewed the literature to discover exactly what has been written about this pathology. In the process I hoped to gain a better understanding of the problem and attempt to define a more concise approach to the injury by consolidating the broad array of articles written on this subject. Then by reviewing our findings in our large series of patients I aimed to discover whether we were encountering similar problems to the surgeons who had preceded us and whether we had made any new discoveries that might positively contribute to the future management of these patients

Comparative effects of calcium channel antagonism and beta-1 selective blockade on exercise performance in physically active hypertensive patients

The current recommendations by the American Heart Association for health promotion are that all persons should partake in regular physical activity in order to reduce the risk of cardiovascular disease. Regular physical exercise reduces blood pressure and is an important component of the management of hypertension. It is therefore important that patients with hypertension participate in habitual physical exercise. Many hypertensive patients who exercise will require anti-hypertensive medication. However, some antihypertensive agents cause fatigue during exercise. In order for patients to gain the full benefits of an active lifestyle, it is important that the prescribed antihypertensive agent does not prevent them performing and enjoying sustained exercise. It has been well documented that β-blockers cause premature fatigue during physical exercise. The effects on exercise performance of other first line antihypertensive medications, such as calcium channel antagonists have not been extensively investigated. In particular, the effects of these agents on prolonged submaximal exercise endurance have not been well studied. The object of this thesis was to compare the effects of isradipine, a dihydropyridine calcium channel antagonist, to those of atenolol, a β₁-selective antagonist, on maximal and submaximal exercise performance and on short duration high-intensity exercise in physically active hypertensive patients. The study design was a crossover trial where drug treatments were double blinded and randomised. Physically active volunteers with mild to moderate hypertension were recruited. 11 subjects performed i) progressive exercise to exhaustion for determination of maximal oxygen consumption (VO₂max), maximal work load and cardiorespiratory responses to maximal exercise, ii) prolonged submaximal exercise for determination of exercise endurance, cardiorespiratory responses and ratings of perceived exertion (APE), and iii) short duration, high intensity exercise consisting of a 30 second maximal exercise test (Wingate test) to determine skeletal muscle power output, following 4 weeks ingestion of isradipine (2.5mg bd), atenolol (50mg bd) or placebo. Diastolic blood pressure at rest was reduced by both atenolol and isradipine, but was lowered to a greater extent by atenolol (83.3 vs 89.0 vs 96.1 mmHg, atenolol vs isradipine vs placebo, p<.0005). Systolic blood pressure at rest tended to be similarly reduced by both agents, but was significantly reduced during maximal and submaximal exercise by atenolol only (p<.001, atenolol vs isradipine, placebo). Heart rate at rest and during maximal and submaximal exercise was decreased by atenolol only (p<.0005, atenolol vs isradipine, placebo). Maximal exercise performance was reduced after atenolol ingestion compared to placebo but not after isradipine ingestion. Peak workload achieved during the maximal exercise test was decreased after atenolol but unchanged after isradipine ingestion (214 vs 243 W, atenolol vs placebo, p<.01). Similarly, VO₂max was reduced after atenolol compared to placebo but was unchanged after isradipine ingestion (33.6 vs 36.4, 33.6 vs 36.1 mlO₂/kg/min, atenolol vs placebo, atenolol vs isradipine, p<.05). Both atenolol and isradipine ingestion reduced submaximal endurance time compared to placebo (27.8 vs 46.4, 34.4 vs 46.4 min, atenolol vs placebo, isradipine vs placebo, p<.005), and increased rating of perceived exertion (APE) after 30 min of submaximal exercise (p<.05). Submaximal oxygen consumption (VO₂), ventilation, respiratory exchange ratio (REA) and blood lactate, glucose and free fatty acid concentrations were not altered after the ingestion of either agent. Neither agent influenced peak skeletal muscle power, total work done, or rate of fatigue during the Wingate test compared to placebo. The results of these studies indicate that impaired performance and increased RPE during submaximal exercise after ingestion of either atenolol or isradipine is not due to alterations of ventilation, VO₂, RER, or blood lactate, glucose and free fatty acid concentrations during prolonged submaximal exercise. Similarly, reduced submaximal exercise performance after atenolol or isradipine ingestion is not due to factors which would also limit the ability of skeletal muscle to perform short duration, high intensity exercise before a bout of prolonged exercise. This study demonstrates that prolonged submaximal exercise testing can reveal an impairment in exercise performance after ingestion of antihypertensive medication which is not evident during maximal exercise testing. This finding is important as prolonged submaximal exercise is the form of exercise which most hypertensive patients actually perform. Further research is required on the effects of anti-hypertensive medications on submaximal exercise performance before firm recommendations can be made regarding medications most suitable for the physically active hypertensive patient. The results of these and other studies indicate that it is not yet possible to make claims that the calcium channel antagonist agents are without effect on physical exercise performance in physically active hypertensive patients

Finding the ‘Who’ in Whooping Cough: Vaccinated Siblings are Important Pertussis Sources in Infants 6 Months of Age and Under

Objectives: To describe the epidemiology of pertussis, and to identify changes in the source of pertussis in infants 6 months of age and under, during the 2008–2012 epidemic in south metropolitan Perth. Design and setting: Analysis of all pertussis cases notified to the South Metropolitan Population Health Unit and recorded on the Western Australian Notifiable Infectious Disease Database over the study period. Information on the source of pertussis was obtained from enhanced surveillance data. Results: Notification rates were highest in the 5–9 years age group, followed by the 0–4 years and 10–14 years age groups. There was a significant increase in the proportion of known sources who were siblings from the early epidemic period of 2008–2010, compared with the peak epidemic period of 2011–2012 (14.3% versus 51.4%, p = 0.002). The majority of sibling sources were fully vaccinated children aged 2 and 3 years. Conclusions: The incidence of pertussis was highest in children aged 12 years and under in this epidemic. At its peak, siblings were the most important sources of pertussis in infants 6 months and younger, particularly fully vaccinated children aged 2 and 3 years. Waning immunity before the booster at 4 years may leave this age group susceptible to infection. Even if cocooning programs could achieve full vaccination coverage of parents and ensure all siblings were fully vaccinated according to national schedules, waning immunity in siblings could provide a means for ongoing transmission to infants. Recent evidence suggests that maternal antenatal vaccination would significantly reduce the risk of pertussis in infants 3 months of age and under

Community-associated Clostridium difficile infection in emergency department patients in Western Australia

Clostridium difficile infection (CDI) is primarily associated with hospitalised patients, however, community-associated CDI (CA-CDI) has increased in Australia. We aimed to investigate the epidemiology and outcomes of CA-CDI cases presenting to hospital emergency departments in Western Australia (WA). A retrospective case-control study of CA-CDI cases presenting at six emergency departments in WA from July 2013 to June 2014 was performed. Clinical signs, recent medication, hospitalisations and potential risk factors for CA-CDI were investigated for cases (n = 34) and unmatched controls (n = 62) who were infected with another gastrointestinal pathogen, including Campylobacter spp., Salmonella spp., Aeromonas spp., Shigella sonnei and Escherichia coli O157. Elevated white cell count (31.3% vs 8.2%, p &lt; 0.01), female gender (67.6% vs 41.9%, p &lt; 0.05), age =65 years (41.2% vs 21.0%, p &lt; 0.05) and antimicrobial use in the previous month (41.2% vs 11.3%, p &lt; 0.01) were significantly more frequent among cases compared to controls. After multivariable analysis, antibiotic use (odds ratio 8.49, 95% confidence interval 2.75–26.21) and age =65 years (3.03, 1.05–8.75) were significantly associated with CA-CDI. Ribotype (RT) 014/020 was most common (40.7%) among 27 C. difficile isolates followed by RTs 002 (14.8%), 001, 056 and 244 (all 7.4%). CA-CDI was associated with advanced age and recent antibiotic use compared to those infected with other gastrointestinal pathogens. RT 014 has also recently been found at high prevalence in public lawn spaces, and previously RT 014 strains from humans and pigs in Australia were closely genetically related, suggesting CA-CDI may be linked with these community reservoirs

Effectiveness evaluation of digital contact tracing for COVID-19 in New South Wales, Australia

Background: Digital proximity tracing apps were rolled out early in the COVID-19 pandemic in many countries to complement conventional contact tracing. Empirical evidence about their benefits for pandemic response remains scarce. We evaluated the effectiveness and usefulness of COVIDSafe, Australia's national smartphone-based proximity tracing app for COVID-19. Methods: In this prospective study, done in New South Wales (NSW), Australia, we included all individuals in the state who were older than 12 years with confirmed, locally acquired SARS-CoV-2 infection between May 4 and Nov 4, 2020. We used data from the NSW Notifiable Conditions Information Management System, the national COVIDSafe database, and information from case interviews, including information on app usage, the number of app-suggested contacts, and the number of app-suggested contacts determined by public health staff to be actual close contacts. We calculated the positive predictive value and sensitivity of COVIDSafe, its additional contact yield, and the number of averted public exposure events. Semi-structured interviews with public health staff were done to assess the app's perceived usefulness. Findings: There were 619 confirmed COVID-19 cases with more than 25 300 close contacts identified by conventional contact tracing during the study period. COVIDSafe was used by 137 (22%) cases and detected 205 contacts, 79 (39%) of whom met the close contact definition. Its positive predictive value was therefore 39%. 35 (15%) of the 236 close contacts who could have been expected to have been using the app during the study period were identified by the app, making its estimated sensitivity 15%. 79 (0·3%) of the estimated 25 300 contacts in NSW were app-suggested and met the close contact definition. The app detected 17 (<0·1%) additional close contacts who were not identified by conventional contact tracing. COVIDSafe generated a substantial additional perceived workload for public health staff and was not considered useful. Interpretation: The low uptake of the app among cases probably led to a reduced sensitivity estimate in our study, given that only contacts who were using the app could be detected. COVIDSafe was not sufficiently effective to make a meaningful contribution to the COVID-19 response in Australia's most populous state over a 6 month period. We provide an empirical evaluation of this digital contact tracing app that questions the potential benefits of digital contact tracing apps to the public health response to COVID-19. Effectiveness evaluations should be integrated into future implementations of proximity contact tracing systems to justify their investment. Funding: New South Wales Ministry of Health (Australia); National Health and Medical Research Council (Australia

Modelling Direct Messaging Networks with Multiple Recipients for Cyber Deception

Cyber deception is emerging as a promising approach to defending networks and systems against attackers and data thieves. However, despite being relatively cheap to deploy, the generation of realistic content at scale is very costly, due to the fact that rich, interactive deceptive technologies are largely hand-crafted. With recent improvements in Machine Learning, we now have the opportunity to bring scale and automation to the creation of realistic and enticing simulated content. In this work, we propose a framework to automate the generation of email and instant messaging-style group communications at scale. Such messaging platforms within organisations contain a lot of valuable information inside private communications and document attachments, making them an enticing target for an adversary. We address two key aspects of simulating this type of system: modelling when and with whom participants communicate, and generating topical, multi-party text to populate simulated conversation threads. We present the LogNormMix-Net Temporal Point Process as an approach to the first of these, building upon the intensity-free modeling approach of Shchur et al. to create a generative model for unicast and multi-cast communications. We demonstrate the use of fine-tuned, pre-trained language models to generate convincing multi-party conversation threads. A live email server is simulated by uniting our LogNormMix-Net TPP (to generate the communication timestamp, sender and recipients) with the language model, which generates the contents of the multi-party email threads. We evaluate the generated content with respect to a number of realism-based properties, that encourage a model to learn to generate content that will engage the attention of an adversary to achieve a deception outcome

Challenges Facing Asian Sex Workers in Western Australia: Implications for Health Promotion and Support Services

Introduction: Asian sex workers are a significant part of the Australian sex industry. Criminal laws, racism, isolation, poor English language skills and stigma and discrimination combine to increase the vulnerability of Asian sex workers in Australia. To inform service delivery and potential legislative reform, we undertook a study of sex worker health and safety in Western Australia with a focus on Asian sex workers. Methods: This was a mixed methods study in which peer researchers played an essential role. We undertook a survey (available online and in paper form and translated into three languages other than English), semi-structured interviews with sex workers, and interviews with key advisors. Results: In our study, Asian sex workers were older, had lower levels of education, more likely to have sex work as their main source of income, work longer hours and work exclusively in a shop-front massage parlor compared to their non-Asian counterparts. The vast majority of Asian sex workers in our study said they had poor English language skills and the greatest proportion spoke Chinese languages. Sex work had a positive impact on the well-being of many respondents, and their level of psychological distress was similar to the general Australian population. Stress and "bad clients" were common negative impacts of sex work. Asian study participants were less likely than their non-Asian counterparts to smoke, undertake risky drinking or use illicit drugs. A similar proportion of Asian sex workers reported being assaulted compared to their non-Asian counterparts. Discussion/Conclusion: The major challenges facing Asian sex workers in WA seem to be stigma and discrimination, stress, social isolation, and confusion about their legal standing leading to a fear of authorities, particularly the police. Our findings support the need for enhanced targeted peer-based health promotion outreach services for Asian sex workers, increased Asian language services in sexual health clinics and decriminalization of sex work