Deception

Prose by Stephen Neal

Option Investor Rationality Revisited

Do option investors rationally exercise their options? Numerous studies report evidence of irrational behavior. In this paper, we pay careful attention to intraday option quotes and reach the opposite conclusion. An exercise boundary violation (EBV) occurs when the best bid price for an American option is below the option’s intrinsic value. Far from being unusual, we show that EBVs occur very frequently. Under these conditions, the rational response of an investor liquidating an option is to exercise the option rather than sell it. Empirically, we find that the likelihood of early exercise is strongly influenced by the existence and duration of EBVs. Not only do these results reverse standard theory on American option valuation and optimal exercise strategy, but they also suggest that the ability to avoid selling at an EBV price creates an additional source of value for American options that is unrelated, and in addition to, dividend payments. This additional value may help explain why American options appear overpriced relative to European options

The incidence and prevention of Postoperative Venous Thrombosis

In the last few years a very high incidence of deep vein thrombosis has been reported in the literature. Venous thrombosis and its sequel, pulmonary embolus account for 12. 5% of all postoperative deaths and is the single greatest threat to recovery after surgical operations. This study was undertaken to investigate the incidence of postoperative deep vein thrombosis occurring at Groote Schuur Hospital using the newer methods of diagnosis. No previous similar study has been conducted in South Africa. The high-risk factors predisposing to venous thrombosis have been assessed and the techniques of diagnosis using Radio-active fibrinogen, Doppler ultrasound and Venography have been studied. The local findings reported in this study confirmed the high reported incidence. Methods of prevention of venous thrombosis using low doses heparin and sodium pentosan polysulphate have been assessed

An Exploration of the Promises and Limitations of Passive Direct Methanol Fuel Cells

While Direct Methanol Fuel Cells (DMFC) have a promising future as a long-lasting and environmentally friendly energy source, the use of balance of plant (BOP) equipment, such as pumps, fans, and compressors, create a complex system that can significantly reduce plant efficiency and increase cost. As an alternative, passive DMFCs have been designed and studied due to their ability to run under ambient conditions without any BOP equipment. However, before they become a feasible energy source, more must be understood about their promise and limitations. In this thesis, performance of a self-designed and constructed passive DMFC was investigated. In addition, an analytical mathematical model was developed in order to gain a better understanding of the limitations of the passive DMFC. The model was compared with literature\u27s data to ensure reliability. Passive DMFCs, consisting of one to twelve Membrane Electrode Assemblies (MEAs) were designed, constructed and tested. The smaller scale fuel cell was optimized using different setups and elaborately tested using a variety of fuels, most notably methanol chafing gel, to determine an optimal performance curve. The larger fuel cells were further used to test for long-term performance and practical feasibility. The compact four-cell units could run for at least 24 hours and can provide performance akin to an AA battery. A larger 12-cell fuel cell was also designed and built to test feasibility as a convenient power supply for camping equipment and other portable electronics, and was tested with neat methanol and methanol gel. In all fuel cell prototypes, polarization plots were obtained, along with open circuit voltage (OCV) plots and long-term performance plots. While it is currently not possible to differentiate which methanol fuel source is the best option without a more thorough investigation, methanol gel has shown great potential as a readily available commercial fuel. The three largest restrictions in passive DMFC performance are 1) slow mass transfer of fuel to the anode, 2) slow kinetics of methanol and oxygen electrodes, and 3) methanol crossover. The developed model correctly predicts the effect of methanol crossover and the resulting crossover current on OCV as well as on performance of the fuel cell over the entire voltage-current range. Further, the model correctly predicts the effect of increasing methanol feed concentration on reduced OCV but increased limiting current density. The effect of the proton exchange membrane thickness is also well explained. Finally, the model describes the significant power losses from larger overpotentials, as well as crossover current, and the resulting significant heat generated and low efficiency. Overall, PDMFCs show great promise for potential application provided the cost can be reduced significantly

Spatially dependent electromagnetically induced transparency

Recent years have seen vast progress in the generation and detection of structured light, with potential applications in high capacity optical data storage and continuous variable quantum technologies. Here we measure the transmission of structured light through cold rubidium atoms and observe regions of electromagnetically induced transparency (EIT). We use q-plates to generate a probe beam with azimuthally varying phase and polarisation structure, and its right and left circular polarisation components provide the probe and control of an EIT transition. We observe an azimuthal modulation of the absorption profile that is dictated by the phase and polarisation structure of the probe laser. Conventional EIT systems do not exhibit phase sensitivity. We show, however, that a weak transverse magnetic field closes the EIT transitions, thereby generating phase dependent dark states which in turn lead to phase dependent transparency, in agreement with our measurements.Comment: 5 Pages, 5 Figure

Developing Evidence-Based Practice in Chaplaincy: A Study of Unit and Chaplain-Specific Integration

Health care chaplains provide spiritual care across diverse hospital units. As a result of the complex and interprofessional nature of health care services, different units are associated with unique integration and collaboration needs. Effective chaplain practice and patient-centered care are enhanced by sensitivity to unit differences. Our research, aimed at quality improvement, examined unit and chaplain integration to promote unit-specific evidence-based practice. Integration was conceptualized by five dimensions: interdependence, newly created professional activities, flexibility, collective ownership of goals, reflection on process. data was collected using the Interprofessional Integration and Collaboration Instrument (Bronstein, 2002), which has appropriate measurement quality (Bainbridge et al., 2015). Addition questions captured chaplain-specific integration and methods of chaplain engagement (charting, referrals). The survey was available in electronic and paper format. Over 150 staff from 10 units participated in the 2017 convenience survey. Survey results were used to develop profiles of unit and chaplain-specific integration; of chaplain engagement; and of perceived contributions of chaplains to patient care. Demographic information was summarized to determine representativeness. The findings contribute to quality improvement and evidence-based practice by identifying how chaplains can effectively integrated within specific units. The findings are being disseminated to unit stakeholders, hospital administration, and other chaplains.https://scholarscompass.vcu.edu/gradposters/1026/thumbnail.jp

The Management of Change: A Case Study

A literature review was conducted to identify some of the requirements for competitiveness and change that are being promoted by leaders in the manufacturing field. A survey was developed based on the literature review and was subsequently administered, via the case study method, at a midwestern US agricultural chemicals firm to determine the company\u27s degree of compliance with the literature\u27\u27s recommendations. To a large degree, the company complied with the requirements

Inorganic carbon dominates total dissolved carbon concentrations and fluxes in British rivers: application of the THINCARB model – thermodynamic modelling of inorganic carbon in freshwaters

River water-quality studies rarely measure dissolved inorganic carbon (DIC) routinely, and there is a gap in our knowledge of the contributions of DIC to aquatic carbon fluxes and cycling processes. Here, we present the THINCARB model (THermodynamic modelling of INorganic CARBon), which uses widely-measured determinands (pH, alkalinity and temperature) to calculate DIC concentrations, speciation (bicarbonate, HCO3−; carbonate, CO32 −; and dissolved carbon dioxide, H2CO3⁎) and excess partial pressures of carbon dioxide (EpCO2) in freshwaters. If calcium concentration measurements are available, THINCARB also calculates calcite saturation. THINCARB was applied to the 39-year Harmonised Monitoring Scheme (HMS) dataset, encompassing all the major British rivers discharging to the coastal zone. Model outputs were combined with the HMS dissolved organic carbon (DOC) datasets, and with spatial land use, geology, digital elevation and hydrological datasets. We provide a first national-scale evaluation of: the spatial and temporal variability in DIC concentrations and fluxes in British rivers; the contributions of DIC and DOC to total dissolved carbon (TDC); and the contributions to DIC from HCO3− and CO32 − from weathering sources and H2CO3⁎ from microbial respiration. DIC accounted for > 50% of TDC concentrations in 87% of the HMS samples. In the seven largest British rivers, DIC accounted for an average of 80% of the TDC flux (ranging from 57% in the upland River Tay, to 91% in the lowland River Thames). DIC fluxes exceeded DOC fluxes, even under high-flow conditions, including in the Rivers Tay and Tweed, draining upland peaty catchments. Given that particulate organic carbon fluxes from UK rivers are consistently lower than DOC fluxes, DIC fluxes are therefore also the major source of total carbon fluxes to the coastal zone. These results demonstrate the importance of accounting for DIC concentrations and fluxes for quantifying carbon transfers from land, via rivers, to the coastal zone