The relationship between implied and realized volatility : evidence from the Australian stock index option market

This paper examines the relationship between the volatility implied in option prices and the subsequently realized volatility by using the S&P/ASX 200 index options (XJO) traded on the Australian Stock Exchange (ASX) during a period of 5 years. Unlike stock index options such as the S&P 100 index options in the US market, the S&P/ASX 200 index options are traded infrequently and in low volumes, and have a long maturity cycle. Thus an errors-in-variables problem for measurement of implied volatility is more likely to exist. After accounting for this problem by instrumental variable method, it is found that both call and put implied volatilities are superior to historical volatility in forecasting future realized volatility. Moreover, implied call volatility is nearly an unbiased forecast of future volatility.

Nursing care of the mechanically ventilated patient: what does the evidence say? Part one.

The care of the mechanically ventilated patient is at the core of a nurse's clinical practice in the Intensive Care Unit (ICU). Published work relating to the numerous nursing issues of the care of the mechanically ventilated patient in the ICU is growing significantly. Literature focuses on patient assessment and management strategies for patient stressors, pain and sedation. Yet this literature is fragmentary by nature. The purpose of this paper is to provide a single comprehensive examination of the evidence related to the care of the mechanically ventilated patient. In part one of this two-part paper, the evidence on nursing care of the mechanically ventilated patient is explored with specific focus on patient safety: particularly patient and equipment assessment. Part two of the paper examines the evidence related to the mechanically ventilated patient's comfort, the patient/family unit, patient position, hygiene, management of stressors, pain management and sedation.

Nursing care of the mechanically ventilated patient: What does the evidence say?: Part two

The care of the mechanically ventilated patient is a fundamental component of a nurse's clinical practice in the intensive care unit (ICU). Published work relating to the numerous nursing issues of the care of the mechanically ventilated patient in the ICU is growing significantly, yet is fragmentary by nature. The purpose of this paper is to provide a single comprehensive examination of the evidence related to the care of the mechanically ventilated patient. In part one of this two-part paper, the evidence on nursing care of the mechanically ventilated patient was explored with specific focus on patient safety: particularly patient and equipment assessment. This article, part two, examines the evidence related to the mechanically ventilated patient's comfort: patient position, hygiene, management of stressors (such as communication, sleep disturbance and isolation), pain management and sedation.

'Caring for' behaviours that indicate to patients that nurses 'care about' them

This paper is a report of a study to explore what constitutes nurse-patient interactions and to ascertain patients' perceptions of these interactions. BACKGROUND: Nurses maintain patient integrity through caring practices. When patients feel disempowered or that their integrity is threatened they are more likely to make a complaint. When nurses develop a meaningful relationship with patients they recognize and address their concerns. It is increasingly identified in the literature that bureaucratic demands, including increased workloads and reduced staffing levels, result in situations where the development of a 'close' relationship is limited. METHOD: Data collection took two forms: twelve 4-hour observation periods of nurse-patient interactions in one cubicle (of four patients) in a medical and a surgical ward concurrently over a 4-week period; and questionnaires from inpatients of the two wards who were discharged during the 4-week data collection period in 2005. FINDINGS: Observation data showed that nurse-patient interactions were mostly friendly and informative. Opportunities to develop closeness were limited. Patients were mostly satisfied with interactions. The major source of dissatisfaction was when patients perceived that nurses were not readily available to respond to specific requests. Comparison of the observation and survey data indicated that patients still felt 'cared for' even when practices did not culminate in a 'connected' relationship. CONCLUSION: The findings suggest that patients believe that caring is demonstrated when nurses respond to specific requests. Patient satisfaction with the service is more likely to be improved if nurses can readily adapt their work to accommodate patients' requests or, alternatively, communicate why these requests cannot be immediately addressed.

The relationship between culture, attitude, social networks and quality of life in midlife Australian and Taiwanese citizens

Objectives: The objectives of this study were to specifically investigate the differences in culture, attitudes and social networks between Australian and Taiwanese men and women and identify the factors that predict midlife men and women’s quality of life in both countries. Methods: A stratified random sample strategy based on probability proportional sampling (PPS) was conducted to investigate 278 Australian and 398 Taiwanese midlife men and women’s quality of life. Multiple regression modelling and classification and regression trees (CARTs) were performed to examine the potential differences on culture, attitude, social networks, social demographic factors and religion/spirituality in midlife men and women’s quality of life in both Australia and Taiwan. Results: The results of this study suggest that culture involves multiple functions and interacts with attitudes, social networks and individual factors to influence a person’s quality of life. Significant relationships were found between the interaction between cultural circumstances and a person’s internal and external factors. The research found that good social support networks and a healthy optimistic disposition may significantly enhance midlife men and women’s quality of life. Conclusion: The study indicated that there is a significant relationship between culture, attitude, social networks and quality of life in midlife Australian and Taiwanese men and women. People who had higher levels of horizontal individualism and collectivism, positive attitudes and better social support had better psychological, social, physical and environmental health, while it emerged that vertical individualists with competitive characteristics would experience a lower quality of life. This study has highlighted areas where opportunities exist to further reflect upon contemporary social health policies for Australian and Taiwanese societies and also within the global perspective, in order to provide enhanced quality care for growing midlife populations.

Part 2. Chemical and physical restraints in the management of mechanically ventilated patients in the ICU: A patient perspective

An important goal of the care for the mechanically ventilated patient is to minimize patient discomfort and anxiety. This is partly achieved by frequent use of chemical and physical restraints. The majority of patients in intensive care will receive some form of sedation. The goal and use of sedation has changed considerably over the past few decades with literature evidencing trends toward overall lighter sedation levels and daily interruption of sedation. Conversely, the use of physical restraint for the ventilated patient in ICU differs considerably between nations and continents. A large portion of the literature on the use of physical restraint is from general hospital wards and residential homes, and not from the ICU environment. Recent literature suggests minimal use of physical restraint in the ICU, and that reduction programmes have been initiated. However, very few papers illuminate the patient's experience of physical and chemical restraints as a treatment strategy. In Part 1 of this two-part review, the evidence on chemical and physical restraints was explored with specific focus on definitions of terms, unplanned extubation, agitation, delirium as well as the impact of nurse–patient ratios in the ICU on these issues. This paper, Part 2, examines the evidence related to chemical and physical restraints from the mechanically ventilated patient's perspective.

Implicit discount rates and fisheries management : is there a relationship?

Fishers are faced with multiple risks, including unpredictability of future catch rates, prices and costs. While the latter are largely beyond the control of fisheries managers, effective fisheries management should reduce uncertainty about future catches. Different management instruments are likely to have different impacts on the risk perception of fishers, and this should manifest itself in their implicit discount rate. Assuming licence and quota values represent the net present value of the flow of expected future profits, then a proxy for the implicit discount rate of vessels in a fishery can be derived by the ratio of the average level of profits to the average licence/quota value. From this, an indication of the risk perception can be derived, assuming higher discount rates reflect higher levels of systematic risk. In this paper, we apply the capital asset pricing model (CAPM) to determine the risk premium implicit in the discount rates for a range of Australian fisheries, and compare this with the set of management instruments in place. We test the assumption that rights based management instruments lower perceptions of risk in fisheries. We find little evidence to support this assumption. although the analysis was based on only limited data.

Development of patient-specific computer simulation tools for endoscopic scoliosis surgery

Endoscopic approaches for anterior correction of idiopathic scoliosis are a relatively new surgical technique. This paper describes the development of patient-specific finite element modelling techniques to investigate the biomechanics of single rod anterior scoliosis correction. Spinal geometry is obtained from pre-operative CT scans and material properties for osteo-ligamentous spinal tissues are based on existing literature. The techniques being developed will allow pre-surgical prediction of stresses, forces and deformations in spinal tissues, rods and screws under post-operative physiological loads.

Application of data mining techniques in the prediction of coronary artery disease : use of anaesthesia time-series and patient risk factor data

The high morbidity and mortality associated with atherosclerotic coronary vascular disease (CVD) and its complications are being lessened by the increased knowledge of risk factors, effective preventative measures and proven therapeutic interventions. However, significant CVD morbidity remains and sudden cardiac death continues to be a presenting feature for some subsequently diagnosed with CVD. Coronary vascular disease is also the leading cause of anaesthesia related complications. Stress electrocardiography/exercise testing is predictive of 10 year risk of CVD events and the cardiovascular variables used to score this test are monitored peri-operatively. Similar physiological time-series datasets are being subjected to data mining methods for the prediction of medical diagnoses and outcomes. This study aims to find predictors of CVD using anaesthesia time-series data and patient risk factor data. Several pre-processing and predictive data mining methods are applied to this data. Physiological time-series data related to anaesthetic procedures are subjected to pre-processing methods for removal of outliers, calculation of moving averages as well as data summarisation and data abstraction methods. Feature selection methods of both wrapper and filter types are applied to derived physiological time-series variable sets alone and to the same variables combined with risk factor variables. The ability of these methods to identify subsets of highly correlated but non-redundant variables is assessed. The major dataset is derived from the entire anaesthesia population and subsets of this population are considered to be at increased anaesthesia risk based on their need for more intensive monitoring (invasive haemodynamic monitoring and additional ECG leads). Because of the unbalanced class distribution in the data, majority class under-sampling and Kappa statistic together with misclassification rate and area under the ROC curve (AUC) are used for evaluation of models generated using different prediction algorithms. The performance based on models derived from feature reduced datasets reveal the filter method, Cfs subset evaluation, to be most consistently effective although Consistency derived subsets tended to slightly increased accuracy but markedly increased complexity. The use of misclassification rate (MR) for model performance evaluation is influenced by class distribution. This could be eliminated by consideration of the AUC or Kappa statistic as well by evaluation of subsets with under-sampled majority class. The noise and outlier removal pre-processing methods produced models with MR ranging from 10.69 to 12.62 with the lowest value being for data from which both outliers and noise were removed (MR 10.69). For the raw time-series dataset, MR is 12.34. Feature selection results in reduction in MR to 9.8 to 10.16 with time segmented summary data (dataset F) MR being 9.8 and raw time-series summary data (dataset A) being 9.92. However, for all time-series only based datasets, the complexity is high. For most pre-processing methods, Cfs could identify a subset of correlated and non-redundant variables from the time-series alone datasets but models derived from these subsets are of one leaf only. MR values are consistent with class distribution in the subset folds evaluated in the n-cross validation method. For models based on Cfs selected time-series derived and risk factor (RF) variables, the MR ranges from 8.83 to 10.36 with dataset RF_A (raw time-series data and RF) being 8.85 and dataset RF_F (time segmented time-series variables and RF) being 9.09. The models based on counts of outliers and counts of data points outside normal range (Dataset RF_E) and derived variables based on time series transformed using Symbolic Aggregate Approximation (SAX) with associated time-series pattern cluster membership (Dataset RF_ G) perform the least well with MR of 10.25 and 10.36 respectively. For coronary vascular disease prediction, nearest neighbour (NNge) and the support vector machine based method, SMO, have the highest MR of 10.1 and 10.28 while logistic regression (LR) and the decision tree (DT) method, J48, have MR of 8.85 and 9.0 respectively. DT rules are most comprehensible and clinically relevant. The predictive accuracy increase achieved by addition of risk factor variables to time-series variable based models is significant. The addition of time-series derived variables to models based on risk factor variables alone is associated with a trend to improved performance. Data mining of feature reduced, anaesthesia time-series variables together with risk factor variables can produce compact and moderately accurate models able to predict coronary vascular disease. Decision tree analysis of time-series data combined with risk factor variables yields rules which are more accurate than models based on time-series data alone. The limited additional value provided by electrocardiographic variables when compared to use of risk factors alone is similar to recent suggestions that exercise electrocardiography (exECG) under standardised conditions has limited additional diagnostic value over risk factor analysis and symptom pattern. The effect of the pre-processing used in this study had limited effect when time-series variables and risk factor variables are used as model input. In the absence of risk factor input, the use of time-series variables after outlier removal and time series variables based on physiological variable values’ being outside the accepted normal range is associated with some improvement in model performance.

The relationship between particulate air pollution and emergency hospital visits for hypertension in Beijing, China

BACKGROUND: A number of epidemiological studies have examined the adverse effect of air pollution on mortality and morbidity. Also, several studies have investigated the associations between air pollution and specific-cause diseases including arrhythmia, myocardial infarction, and heart failure. However, little is known about the relationship between air pollution and the onset of hypertension. OBJECTIVE: To explore the risk effect of particulate matter air pollution on the emergency hospital visits (EHVs) for hypertension in Beijing, China. METHODS: We gathered data on daily EHVs for hypertension, fine particulate matter less than 2.5 microm in aerodynamic diameter (PM(2.5)), particulate matter less than 10 microm in aerodynamic diameter (PM(10)), sulfur dioxide, and nitrogen dioxide in Beijing, China during 2007. A time-stratified case-crossover design with distributed lag model was used to evaluate associations between ambient air pollutants and hypertension. Daily mean temperature and relative humidity were controlled in all models. RESULTS: There were 1,491 EHVs for hypertension during the study period. In single pollutant models, an increase in 10 microg/m(3) in PM(2.5) and PM(10) was associated with EHVs for hypertension with odds ratios (overall effect of five days) of 1.084 (95% confidence interval (CI): 1.028, 1.139) and 1.060% (95% CI: 1.020, 1.101), respectively. CONCLUSION: Elevated levels of ambient particulate matters are associated with an increase in EHVs for hypertension in Beijing, China.