Wake angle for surface gravity waves on a finite depth fluid

Linear water wave theory suggests that wave patterns caused by a steadily moving disturbance are contained within a wedge whose half-angle depends on the depth-based Froude number $F_H$. For the problem of flow past an axisymmetric pressure distribution in a finite-depth channel, we report on the apparent angle of the wake, which is the angle of maximum peaks. For moderately deep channels, the dependence of the apparent wake angle on the Froude number is very different to the wedge angle, and varies smoothly as $F_H$ passes through the critical value $F_H=1$. For shallow water, the two angles tend to follow each other more closely, which leads to very large apparent wake angles for certain regimes.

Depth of anaesthesia monitoring during procedural sedation and analgesia: A systematic review protocol

Background Procedural sedation and analgesia (PSA) is used to attenuate the pain and distress that may otherwise be experienced during diagnostic and interventional medical or dental procedures. As the risk of adverse events increases with the depth of sedation induced, frequent monitoring of level of consciousness is recommended. Level of consciousness is usually monitored during PSA with clinical observation. Processed electroencephalogram-based depth of anaesthesia (DoA) monitoring devices provide an alternative method to monitor level of consciousness that can be used in addition to clinical observation. However, there is uncertainty as to whether their routine use in PSA would be justified. Rigorous evaluation of the clinical benefits of DoA monitors during PSA, including comprehensive syntheses of the available evidence, is therefore required. One potential clinical benefit of using DoA monitoring during PSA is that the technology could improve patient safety by reducing sedation-related adverse events, such as death or permanent neurological disability. We hypothesise that earlier identification of lapses into deeper than intended levels of sedation using DoA monitoring leads to more effective titration of sedative and analgesic medications, and results in a reduction in the risk of adverse events caused by the consequences of over-sedation, such as hypoxaemia. The primary objective of this review is to determine whether using DoA monitoring during PSA in the hospital setting improves patient safety by reducing the risk of hypoxaemia (defined as an arterial partial pressure of oxygen below 60 mmHg or percentage of haemoglobin that is saturated with oxygen [SpO2] less than 90 %). Other potential clinical benefits of using DoA monitoring devices during sedation will be assessed as secondary outcomes. Methods/design Electronic databases will be systematically searched for randomized controlled trials comparing the use of depth of anaesthesia monitoring devices with clinical observation of level of consciousness during PSA. Language restrictions will not be imposed. Screening, study selection and data extraction will be performed by two independent reviewers. Disagreements will be resolved by discussion. Meta-analyses will be performed if suitable. Discussion This review will synthesise the evidence on an important potential clinical benefit of DoA monitoring during PSA within hospital settings.

Motorcyclist hazard perception research: The last 10 years

Motorcycle trauma is a serious issue in Queensland and throughout Australia; the fatality rate per 100 million kilometres travelled for motorcycle riders in Australia is nearly 30 times the rate for drivers of other vehicles (Australian Transport Safety Bureau, 2002). In 2009, the then Queensland Transport (later the Department of Transport and Main Roads or TMR) appointed CARRS-Q to provide a three-year program of Road Safety Research Services for Motorcycle Rider Safety. Funding for this research originated from the Motor Accident Insurance Commission who had the uncommon foresight to fund such a comprehensive program of research.

Two-dimensional bow and stern flows in a finite-depth fluid with constant vorticity

This thesis is concerned with two-dimensional free surface flows past semi-infinite surface-piercing bodies in a fluid of finite-depth. Throughout the study, it is assumed that the fluid in question is incompressible, and that the effects of viscosity and surface tension are negligible. The problems considered are physically important, since they can be used to model the flow of water near the bow or stern of a wide, blunt ship. Alternatively, the solutions can be interpreted as describing the flow into, or out of, a horizontal slot. In the past, all research conducted on this topic has been dedicated to the situation where the flow is irrotational. The results from such studies are extended here, by allowing the fluid to have constant vorticity throughout the flow domain. In addition, new results for irrotational flow are also presented. When studying the flow of a fluid past a surface-piercing body, it is important to stipulate in advance the nature of the free surface as it intersects the body. Three different possibilities are considered in this thesis. In the first of these possibilities, it is assumed that the free surface rises up and meets the body at a stagnation point. For this configuration, the nonlinear problem is solved numerically with the use of a boundary integral method in the physical plane. Here the semi-infinite body is assumed to be rectangular in shape, with a rounded corner. Supercritical solutions which satisfy the radiation condition are found for various values of the Froude number and the dimensionless vorticity. Subcritical solutions are also found; however these solutions violate the radiation condition and are characterised by a train of waves upstream. In the limit that the height of the body above the horizontal bottom vanishes, the flow approaches that due to a submerged line sink in a $90^\circ$ corner. This limiting problem is also examined as a special case. The second configuration considered in this thesis involves the free surface attaching smoothly to the front face of the rectangular shaped body. For this configuration, nonlinear solutions are computed using a similar numerical scheme to that used in the stagnant attachment case. It is found that these solution exist for all supercritical Froude numbers. The related problem of the cusp-like flow due to a submerged sink in a corner is also considered. Finally, the flow of a fluid emerging from beneath a semi-infinite flat plate is examined. Here the free surface is assumed to detach from the trailing edge of the plate horizontally. A linear problem is formulated under the assumption that the elevation of the plate is close to the undisturbed free surface level. This problem is solved exactly using the Wiener-Hopf technique, and subcritical solutions are found which are characterised by a train of sinusoidal waves in the far field. The nonlinear problem is also considered. Exact relations between certain parameters for supercritical flow are derived using conservation of mass and momentum arguments, and these are confirmed numerically. Nonlinear subcritical solutions are computed, and the results are compared to those predicted by the linear theory.

Weight-related risk perception among healthy and overweight pregnant women: A cross-sectional study

Objective The objective of this study was to evaluate weight-related risk perception in early pregnancy and to compare this perception between women commencing pregnancy healthy weight and overweight. Study design Pregnant women (n=664) aged 29±5 (mean±s.d.) years were recruited from a metropolitan teaching hospital in Australia. A self-administered questionnaire was completed at around 16 weeks of gestation. Height measured at baseline and self-reported pre-pregnancy weight were used to calculate body mass index. Cross-sectional analysis was conducted. Differences between groups were assessed using chi-squared tests for categorical variables and t-tests or Mann–Whitney U tests for continuous variables depending on distribution. Result Excess gestational weight gain (GWG) during pregnancy was more important in leading to health problems for women or their child compared with pre-pregnancy weight. Personal risk perception for complications was low for all women, although overweight women had slightly higher scores than healthy-weight women (2.4±1.0 vs 2.9±1.0; P<0.001). All women perceived their risk for complications to be below that of an average pregnant woman. Conclusion Women should be informed of the risk associated with their pre-pregnancy weight (in the case of maternal overweight) and excess GWG. If efforts to raise risk awareness are to result in preventative action, this information needs to be accompanied by advice and appropriate support on how to reduce risk.

The influence of financial risk tolerance and risk perception on individual investment decision-making in a financial advice context

The aim of this thesis is to examine how risk tolerance and risk perception, two important but often misunderstood constructs, jointly influence client investment decisions in a financial advice context. By distinguishing the roles of these two risk constructs in client decision-making, in this thesis a new direction in studying financial/investment risks is provided while practice and regulation in the financial services industry is potentially informed. Based on the literature relating to risks and individual decision-making, a theoretical framework is developed and relevant hypotheses are tested in two studies with financial adviser clients in Australia. Results reveal that financial risk tolerance influences asset allocation both directly and indirectly through risk perception. The intervening role of risk perception suggests that risk tolerance affects how clients perceive the riskiness of an investment product which influences client decision-making.

Infrastructure, investment and development evaluation: A Complex Stakeholder Perception Mapping approach for improving local and regional economic development outcomes

Partial evaluation of infrastructure investments have resulted in expensive mistakes, unsatisfactory outcomes and increased uncertainties for too many stakeholders, communities and economies in both developing and developed nations. "Complex Stakeholder Perception Mapping" (CSPM), is a novel approach that can address existing limitations by inclusively framing, capturing and mapping the spectrum of insights and perceptions using extended Geographic Information Systems. Maps generated in CSPM offer presentations of flexibly combined, complex perceptions of stakeholders on multiple aspects of development. CSPM extends the applications of GIS software in non-spatial mapping and of Multi-Criteria Analysis with a multidimensional evaluation platform and augments decision science capabilities in addressing complexities. Application of CSPM can improve local and regional economic gains from infrastructure projects and aid any multi-objective and multi-stakeholder decision situations.

Common psychotic symptoms can be explained by the theory of ecological perception

The symptoms of psychiatric illness are diverse, as are the causes of the illnesses that cause them. Yet, regardless of the heterogeneity of cause and presentation, a great deal of symptoms can be explained by the failure of a single perceptual function – the reprocessing of ecological perception. It is a central tenet of the ecological theory of perception that we perceive opportunities to act. It has also been found that perception automatically causes actions and thoughts to occur unless this primary action pathway is inhibited. Inhibition allows perceptions to be reprocessed into more appropriate alternative actions and thoughts. Reprocessing of this kind takes place over the entire frontal lobe and it renders action optional. Choice about what action to take (if any) is the basis for the feeling of autonomy and ultimately for the sense-of-self. When thoughts and actions occur automatically (without choice) they appear to originate outside of the self, thereby providing prima facie evidence for some of the bizarre delusions that define schizophrenia such as delusional misidentification, delusions of control and Cotard’s delusion. Automatic actions and thoughts are triggered by residual stimulation whenever reprocessing is insufficient to balance automatic excitatory cues (for whatever reason). These may not be noticed if they are neutral and therefore unimportant whereas actions and thoughts with a positive bias are desirable. Responses to negative stimulus, on the other hand, are always unwelcome, because the actions that are triggered will carry the negative bias. Automatic thoughts may include spontaneous positive feelings of love and joy, but automatic negative thoughts and visualisations are experienced as hallucinations. Not only do these feel like they emerge from elsewhere but they carry a negative bias (they are most commonly critical, rude and are irrationally paranoid). Automatic positive actions may include laughter and smiling and these are welcome. Automatic behaviours that carry a negative bias, however, are unwelcome and like hallucinations, occur without a sense of choice. These include crying, stereotypies, perseveration, ataxia, utilization and imitation behaviours and catatonia.

Investigating the concept of potential quality: An exploratory study in the real estate industry

Purpose The purpose of this research is to examine the concept of “potential quality” – that is, a company's tangible search qualities (such as the physical servicescape and virtual servicescape) – within the context of the real‐estate industry in the USA. Design/methodology/approach This qualitative study collects data by conducting personal in‐depth interviews with 34 respondents who had been recent buyers or renters of property. The data are then coded and themed to identify quality dimensions relevant to this industry. Findings The results indicate that a buyer's perception of the overall service quality of real‐estate service consists of two components: the interaction with a realtor (process quality); and the virtual servicescape, especially the firm's website design and content (potential quality). The study concludes that existing scales (such as SERVQUAL and RESERV) fail to capture the tangible component of service quality sufficiently in the real‐estate industry. Research limitations/implications The study uses data from only one industry (real estate) and from only one demographic segment (professionals in higher education). Practical implications Service providers of intangible, high‐contact services must appreciate the importance of the virtual servicescape as a surrogate quality indicator that can help to reduce information asymmetries and consumers' uncertainty with regard to initiating a business relationship. Real estate firms need to pay attention to the training of agents and the design and content of their e‐service systems. Originality/value This study integrates potential quality, process quality, and outcome quality in a comprehensive proposed model. In particular, the study identifies “potential quality” as a combination of the attributes of the virtual service environment and the physical service environment.

Mothers' perception of the quality of childhood sibling relationships affected by disability

The quality of the sibling relationship has an important role in the development of psychosocial skills throughout childhood. While the literature suggests that the significance of sibling relationships is heightened when one sibling has a disability, empirical findings about the quality of these relationships are few and inconsistent. The present study aimed to address this gap, by investigating mothers’ perspectives about the impact of disability on the quality of the childhood sibling relationship. Forty-one mothers with a child with disability, and 48 with no children with disability completed an online questionnaire that assessed the amount of perceived warmth/closeness and conflict in their children’s sibling relationship. It was found that while there were no differences in reported conflict between the two groups, mothers with a child with disability reported significantly lower warmth/closeness in their children’s sibling relationship than mothers without a child with disability. Demographic variables such as number of children, gender grouping, target gender, target age and age order did not moderate this result. Mothers overall reported significantly more warmth/closeness for younger rather than older children, and more conflict when the sibling was younger than the target child as opposed to older than them. Clinical implications for intervention are discussed.

Angular dependence of the response of the nanoDot OSLD system for measurements at depth in clinical megavoltage beams

Purpose The purpose of this investigation was to assess the angular dependence of a commercial optically stimulated luminescence dosimeter (OSLD) dosimetry system in MV x-ray beams at depths beyondd max and to find ways to mitigate this dependence for measurements in phantoms. Methods Two special holders were designed which allow a dosimeter to be rotated around the center of its sensitive volume. The dosimeter's sensitive volume is a disk, 5 mm in diameter and 0.2 mm thick. The first holder rotates the disk in the traditional way. It positions the disk perpendicular to the beam (gantry pointing to the floor) in the initial position (0°). When the holder is rotated the angle of the disk towards the beam increases until the disk is parallel with the beam (“edge on,” 90°). This is referred to as Setup 1. The second holder offers a new, alternative measurement position. It positions the disk parallel to the beam for all angles while rotating around its center (Setup 2). Measurements with five to ten dosimeters per point were carried out for 6 MV at 3 and 10 cm depth. Monte Carlo simulations using GEANT4 were performed to simulate the response of the active detector material for several angles. Detector and housing were simulated in detail based on microCT data and communications with the manufacturer. Various material compositions and an all-water geometry were considered. Results For the traditional Setup 1 the response of the OSLD dropped on average by 1.4% ± 0.7% (measurement) and 2.1% ± 0.3% (Monte Carlo simulation) for the 90° orientation compared to 0°. Monte Carlo simulations also showed a strong dependence of the effect on the composition of the sensitive layer. Assuming the layer to completely consist of the active material (Al2O3) results in a 7% drop in response for 90° compared to 0°. Assuming the layer to be completely water, results in a flat response within the simulation uncertainty of about 1%. For the new Setup 2, measurements and Monte Carlo simulations found the angular dependence of the dosimeter to be below 1% and within the measurement uncertainty. Conclusions The dosimeter system exhibits a small angular dependence of approximately 2% which needs to be considered for measurements involving other than normal incident beams angles. This applies in particular to clinicalin vivo measurements where the orientation of the dosimeter is dictated by clinical circumstances and cannot be optimized as otherwise suggested here. When measuring in a phantom, the proposed new setup should be considered. It changes the orientation of the dosimeter so that a coplanar beam arrangement always hits the disk shaped detector material from the thin side and thereby reduces the angular dependence of the response to within the measurement uncertainty of about 1%. This improvement makes the dosimeter more attractive for clinical measurements with multiple coplanar beams in phantoms, as the overall measurement uncertainty is reduced. Similarly, phantom based postal audits can transition from the traditional TLD to the more accurate and convenient OSLD.

Excess water storage depth - A water management practice to control simetryn and thiobencarb runoff from paddy fields

Experiments were carried out to verify the effectiveness of the excess water storage depth (EWSD) in reducing runoff losses of simetryn and thiobencarb from paddy fields upon appreciable rainfall events. A paddy plot having an EWSD of 2 cm was effective in controlling runoff with the herbicide losses of less than 1% of the applied herbicides. Meanwhile, a plot with 0-cm EWSD lost 18.1 and 3.7% of the applied mass of simetryn and thiobencarb, respectively. Therefore, an appropriate EWSD is essential during the recommended 7-day water holding period in order to completely hold the water inside the field in case of rainfall.

Behavior of simetryn and thiobencarb in rice paddy lysimeters and the effect of excess water storage depth in controlling herbicide run-off

Eight small-scale lysimeters with different excess water storage depths (EWSDs) were used to investigate the behavior of two herbicides, simetryn and thiobencarb, under paddy conditions. The concentration of simetryn dissipated similarly in all the lysimeters, while the thiobencarb concentration varied significantly because thiobencarb can adsorb onto the dissolved organic matter in a manure slurry, which was applied to six of the lysimeters. The herbicide losses (the percentage of the applied mass) from the lysimeters were reversely proportional with the EWSD. The correlation was stronger for simetryn than for thiobencarb. An appropriate EWSD is required to effectively prevent herbicide run-off from the paddy field, especially when a rainfall event occurs soon after herbicide application.

Crash risk perception of sleepy driving and its comparisons with drink driving and speeding: Which behavior is perceived as the riskiest?

- Objective Driver sleepiness is a major crash risk factor, but may be under-recognized as a risky driving behavior. Sleepy driving is usually rated as less of a road safety issue than more well-known risky driving behaviors, such as drink driving and speeding. The objective of this study was to compare perception of crash risk of sleepy driving, drink driving, and speeding. - Methods In total, 300 Australian drivers completed a questionnaire that assessed crash risk perceptions for sleepy driving, drink driving, and speeding. Additionally, the participants perception of crash risk was assessed for five different contextual scenarios that included different levels of sleepiness (low, high), driving duration (short, long), and time of day/circadian influences (afternoon, night-time) of driving. - Results The analysis confirmed that sleepy driving was considered a risky driving behavior, but not as risky as high levels of speeding (p < .05). Yet, the risk of crashing at 4 am was considered as equally risky as low levels of speeding (10 km over the limit). The comparisons of the contextual scenarios revealed driving scenarios that would arguably be perceived as quite risky due to time of day/circadian influences were not reported as high risk. - Conclusions The results suggest a lack of awareness or appreciation of circadian rhythm functioning, particularly the descending phase of circadian rhythm that promotes increased sleepiness in the afternoon and during the early hours of the morning. Yet, the results suggested an appreciation of the danger associated with long distance driving and driver sleepiness. Further efforts are required to improve the community’s awareness of the impairing effects from sleepiness and in particular, knowledge regarding the human circadian rhythm and the increased sleep propensity during the circadian nadir.

Do stakeholders or social obligations drive corporate social and environmental responsibility reporting? Managerial views from a developing country

Purpose – The purpose of this study is to explore senior managers’ perception and motivations of corporate social and environmental responsibility (CSER) reporting in the context of a developing country, Bangladesh. Design/methodology/approach – In-depth semi-structured interviews were conducted with 25 senior managers of companies listed on the Dhaka Stock Exchange. Publicly available annual reports of these companies were also analysed. Findings – The results indicate that senior managers perceive CSER reporting as a social obligation. The study finds that the managers focus mostly on child labour, human resources/rights, responsible products/services, health education, sports and community engagement activities as part of the social obligations. Interviewees identify a lack of a regulatory framework along with socio-cultural and religious factors as contributing to the low level of disclosures. These findings suggest that CSER reporting is not merely stakeholder-driven, but rather country-specific social and environmental issues play an important role in relation to CSER reporting practices. Research limitations/implications – This paper contributes to engagement-based studies by focussing on CSER reporting practices in developing countries and are useful for academics, practitioners and policymakers in understanding the reasons behind CSER reporting in developing countries. Originality/value – This paper addresses a literature “gap” in the empirical study of CSER reporting in a developing country, such as Bangladesh. This study fills a gap in the existing literature to understand managers’ motivations for CSER reporting in a developing country context. Managerial perceptions on CSER issues are largely unexplored in developing countries.