Mean Reversion in Equilibrium Asset Prices

Recent empirical studies have found that stock returns contain substantial negative serial correlation at long horizons. We examine this finding with a series of Monte Carlo simulations in order to demonstrate that it is consistent with an equilibrium model of asset pricing. When investors display only a moderate degree of risk aversion, commonly used measures of mean reversion in stock prices calculated from actual returns data nearly always lie within a 60 percent confidence interval of the median of the Monte Carlo distributions. From this evidence, we conclude that the degree of serial correlation in the data could plausibly have been generated by our model.

Cardiopulmonary exercise testing for predicting early outcomes after major cancer resection: A systematic review

Background: Postoperative complications after major surgery are thought to be associated with reduced fitness. Surgical cancer patients are often malnourished, cachexic and subject to neoadjuvant chemotherapy resulting in low preoperative fitness levels. This review examined the associations between aerobic fitness, as determined objectively by preoperative cardiopulmonary exercise testing (CPEX), and short-term morbidity after cancer surgery. Methods: A literature search using databases of PubMed, Medline, Embase, Cumulative Index to Nursing and Allied Health Literature (CINAHL) and the Cochrane Library for studies that examined associations between preoperative CPEX variables and postoperative complications following surgery for the ten commonest cancers. Results: A total of 21 observational studies were identified with 4957 patients that underwent CPEX testing prior to lung, colorectal, liver, oesophagogastric, bladder and pancreas resections. The median sample size was 105 patients (range 64 - 1684). No studies were found for breast or brain cancers or lymphoma. In lung cancer patients undergoing thoracotomy, a VO2peak ≤ 15ml/kg/min was associated with an increased risk of respiratory complications and death. None of the studies in other cancer types had adequate sample sizes to report on mortality. CPEX testing had mostly poor to average discriminatory accuracy to predict postoperative morbidity in other cancer resection surgeries. Findings across studies were inconsistent, and detection and selective reporting biases were likely to be significant. Conclusion: The utility of CPEX testing prior to cancer surgery is questionable and currently should not be used as a discriminatory tool, except in patients undergoing lung cancer resection by thoracotomy. Larger studies with more robust methodologies are currently required to determine the utility of CPEX

Does physical activity protect against the development of gastroesophageal reflux disease, Barrett’s oesophagus and oesophageal adenocarcinoma?:A review of the literature with a meta-analysis

Physical activity affects the functioning of the gastrointestinal system through both local and systemic effects and may play an important role in reducing the risk of esophageal adenocarcinoma. This review assesses the biological mechanisms and epidemiological evidence for the relationship between physical activity and the development of esophageal adenocarcinoma and its precursor diseases: gastroesophageal reflux disease (GORD) and Barrett's esophagus. A search of PubMed, Medline, Embase, and CINAHL was conducted from their inceptions to 25th March 2017 for analytical studies that examined associations between recreational and/or occupational levels of physical activity and the risk of GORD, Barrett's esophagus, and esophageal adenocarcinoma. Where appropriate, a meta-analysis of effects was undertaken. Seven studies were included (2 cohort, 5 case control). For GORD, there were three case-control studies with 10 200 cases among 78 034 participants, with a pooled estimated OR of 0.67 (95% CI 0.57–0.78) for high versus low levels of recreational physical activity. In Barrett's esophagus, there was a single case-control study, which reported no association, OR 1.19 (95% CI 0.82–1.73). For esophageal adenocarcinoma, there were three studies (two prospective cohort, one case control) with 666 cases among 910 376 participants. The largest cohort study reported an inverse association for high versus low levels of recreational physical activity, RR 0.68, 95% CI 0.48–0.96. The remaining two studies reported no associations with either occupational or combined recreational and occupational activity. Heterogeneity in the measurement of exposure (recreational, occupational, and both) made a pooled estimate for esophageal adenocarcinoma inappropriate. Although limited, there is some evidence that higher levels of recreational physical activity may reduce the risk of both GORD and esophageal adenocarcinoma, but further large cohort studies examining the type, intensity and duration of activities that may be beneficial are needed

Relationship of speech rhythm, stuttering frequency and discourse type

The present study aimed to compare the speech rhythm of reading and conversation in Cantonese and investigates the relationship between stuttering frequency and speech rhythm across the two types of discourse. Eight native Cantonese-speaking adults diagnosed with stuttering participated in the study. Each participant read a non-emotion-provoking expository passage in the reading task and engaged in conversation on casual topics with the investigator in the conversation task. Speech rhythm and stuttering frequency of the collected speech samples were analyzed. Speech pattern in reading was shown to be more syllable-timed than in conversation using acoustic analysis. However, results showed no significant difference in stuttering frequency in reading and conversation. The relationship between difference in speech rhythm and stuttering frequency in reading and conversation in Cantonese was discussed with reference to the current model of causes of stuttering and the linguistic features of Cantonese. The findings provided insight on appropriate use of reading and conversation tasks in clinical assessment and treatment of stuttering.published_or_final_versionSpeech and Hearing SciencesBachelorBachelor of Science in Speech and Hearing Science

Promiscuous and lineage-specific roles of cell cycle regulators in haematopoiesis

Haematopoietic cell number is maintained by a delicate balance between cell proliferation, differentiation and death. Gene knockout studies in mice have revealed the complex roles of cyclins, CDKs, and CDK inhibitors in regulating cell proliferation and differentiation in the haematopoietic system. These studies point to families of cell cycle regulators which display both redundant and unique roles within a lineage and developmental-stage specific manner. Moreover, the promiscuity of these cell cycle regulators is critical for haematopoietic cell proliferation and differentiation. In this review, we discuss the current evidence from mouse models that the complexity and multifarious nature of the haematopoietic system is critical for its form and function

Australia\u27s Embrace of a Cashless Society: A Quantitative Analysis

This paper presents a mixed method approach to determine whether Australia is ready to become a cashless society. First, the rising trend of digital payment methods is investigated, followed by a discussion of government policies on digital payments surveying the level of adoption in cashless transactions. Next, a list of cashless society readiness indicators is established, and a research model for the research topic introduced. Data from the Global Findex database and statistical data from the Reserve Bank of Australia were analysed to highlight Australia\u27s readiness for adopting a near cashless society within the research period. As a mixed-method approach was adopted for the research topic, the next step was to interpret quantitative and qualitative data using an integrated approach to provide a better picture of the degree and the likely timeframe Australia becomes cashless in the future

Physical activity in the aetiology and preoperative management of oesophageal adenocarcinoma

Oesophageal adenocarcinoma has the fastest growing incidence of any solid tumour in the western world. Physical activity affects gastric emptying, intra-gastric pressure, systemic inflammation, and the regulation of body weight and may play an important role in the aetiology of the metaplasia-dysplasia-carcinoma sequence of oesophageal adenocarcinoma. Furthermore, exercise causes physiological adaptations resulting in improved cardiac output and lung ventilation volumes, as well as increased capillary and mitochondrial density in skeletal muscle, all of which improves efficiency in cellular aerobic respiration. As major surgery places large physiological stresses on the human body through; blood loss, catabolic muscle breakdown, systemic inflammatory vasodilation, and disruption of normal lung mechanics, the adaptive changes, achieved through preoperative exercise, may maximise cardiopulmonary and skeletal muscle reserves and reduce the risk of postoperative complications after cancer resection surgery (oesophagectomy). This research aimed to investigate: 1) associations between both occupational and recreational levels of physical activity and the development of Barrett’s oesophagus, the precursor lesion of oesophageal adenocarcinoma; 2) the feasibility of delivering a shortterm preoperative exercise programme (prehabilitation) in a feasibility randomised controlled trial; and (3) associations between preoperative aerobic fitness, as measured objectively by cardiopulmonary exercise testing, and postoperative outcomes after oesophagectomy. Results from a population-based prospective cohort study of 30 445 participants suggested a U-shaped association between occupational levels of physical activity and the risk of Barrett’s oesophagus, where moderate levels of activity in standing occupations had an inverse association with disease risk (when compared to sedentary occupations), HR=0.50, 95% CI 0.31-0.82, p=0.006, but heavy manual occupations were associated with an increased risk, HR=1.66, 95% CI 0.91-3.00, p=0.09. No associations were found between recreational activity and the risk of Barrett’s oesophagus (HR 1.34, 95% CI 0.72-2.50, p=0.35, highest vs. lowest levels of activity). A single blinded, parallel group, randomised controlled feasibility trial of prehabilitation in 11 patients with oesophageal adenocarcinoma showed that a hospital-based exercise programme in the time period between completion of neoadjuvant chemotherapy and surgery was safe and acceptable to patients awaiting curative surgery. A hospital-based cohort study of 254 patients found that there was no association between aerobic fitness (VO2peak) and postoperative complications after oesophagectomy (OR 1.00, 95% CI 0.94-1.07, p=0.86). This suggests that the impact of fitness on postoperative outcome, in the context of oesophagectomy, is likely to be insubstantial. Overall, this thesis suggests that occupational levels of physical activity may play a role in the aetiology of oesophageal adenocarcinoma, but preoperative fitness, even if feasibly modifiable with prehabilitation, may not significantly affect the risk of short-term postoperative morbidity after oesophagectomy