Impact forces at dipped rail joints

Impact forces develop at the wheel/rail interface due to the presence of defects in the running surface of the wheel and/ or the railhead. This paper reports on wheel impacts, caused by permanently dipped rail joints, that are characterised by high-frequency impact forces generated by high amplifications of the static load that occur for a very short duration (P1 forces), followed by relatively low frequency, lower amplitude forces (P2 forces) that occur for a longer duration. These impact forces are affected by the design of components adjacent to the wheel and rail, namely the bogie’s primary suspension and rail seat pads; the influences of stiffness and damping characteristics of these components are investigated. A modified three-dimensional simulation model of the dynamics of the wagon/track system that includes defects in the track is created and is used to obtain the time series of the impact force. This is converted into impact force factors that are compared with a set of field-measured data reported in the literature. A simplified equation for the determination of impact force factors due to dipped rail joints is also proposed and validated.

Integrating the impact of climate into event based failure models for water pipes

This paper presents an event-based failure model to predict the number of failures that occur in water distribution assets. Often, such models have been based on analysis of historical failure data combined with pipe characteristics and environmental conditions. In this paper weather data have been added to the model to take into account the commonly observed seasonal variation of the failure rate. The theoretical basis of existing logistic regression models is briefly described in this paper, along with the refinements made to the model for inclusion of seasonal variation of weather. The performance of these refinements is tested using data from two Australian water authorities.

Impact of child labor on academic performance : evidence from the program "Edúcame Primero Colombia"

In this study, the effects of different variables of child labor on academic performance are investigated. To this end, 3302 children participating in the child labor eradication program “Edúcame Primero Colombia” were interviewed. The interview format used for the children's enrollment into the program was a template from which socioeconomic conditions, academic performance, and child labor variables were evaluated. The academic performance factor was determined using the Analytic Hierarchy Process (AHP). The data were analyzed through a logistic regression model that took into account children who engaged in a type of labor (n = 921). The results showed that labor conditions, the number of weekly hours dedicated to work, and the presence of work scheduled in the morning negatively affected the academic performance of child laborers. These results show that the relationship between child labor and academic performance is based on the conflict between these two activities. These results do not indicate a linear and simple relationship associated with the recognition of the presence or absence of child labor. This study has implications for the formulation of policies, programs, and interventions for preventing, eradicating, and attenuating the negative effects of child labor on the social and educational development of children.

An investigation of the impact of various geographical scales for the specification of spatial dependence

Ecological studies are based on characteristics of groups of individuals, which are common in various disciplines including epidemiology. It is of great interest for epidemiologists to study the geographical variation of a disease by accounting for the positive spatial dependence between neighbouring areas. However, the choice of scale of the spatial correlation requires much attention. In view of a lack of studies in this area, this study aims to investigate the impact of differing definitions of geographical scales using a multilevel model. We propose a new approach -- the grid-based partitions and compare it with the popular census region approach. Unexplained geographical variation is accounted for via area-specific unstructured random effects and spatially structured random effects specified as an intrinsic conditional autoregressive process. Using grid-based modelling of random effects in contrast to the census region approach, we illustrate conditions where improvements are observed in the estimation of the linear predictor, random effects, parameters, and the identification of the distribution of residual risk and the aggregate risk in a study region. The study has found that grid-based modelling is a valuable approach for spatially sparse data while the SLA-based and grid-based approaches perform equally well for spatially dense data.

The impact of mobile phone distraction on the braking behaviour of young drivers : a hazard-based duration model

Braking is a crucial driving task with a direct relationship with crash risk, as both excess and inadequate braking can lead to collisions. The objective of this study was to compare the braking profile of young drivers distracted by mobile phone conversations to non-distracted braking. In particular, the braking behaviour of drivers in response to a pedestrian entering a zebra crossing was examined using the CARRS-Q Advanced Driving Simulator. Thirty-two licensed drivers drove the simulator in three phone conditions: baseline (no phone conversation), hands-free, and handheld. In addition to driving the simulator, each participant completed questionnaires related to driver demographics, driving history, usage of mobile phones while driving, and general mobile phone usage history. The drivers were 18–26 years old and split evenly by gender. A linear mixed model analysis of braking profiles along the roadway before the pedestrian crossing revealed comparatively increased decelerations among distracted drivers, particularly during the initial 20 kph of deceleration. Drivers’ initial 20 kph deceleration time was modelled using a parametric accelerated failure time (AFT) hazard-based duration model with a Weibull distribution with clustered heterogeneity to account for the repeated measures experiment design. Factors found to significantly influence the braking task included vehicle dynamics variables like initial speed and maximum deceleration, phone condition, and driver-specific variables such as licence type, crash involvement history, and self-reported experience of using a mobile phone whilst driving. Distracted drivers on average appear to reduce the speed of their vehicle faster and more abruptly than non-distracted drivers, exhibiting excess braking comparatively and revealing perhaps risk compensation. The braking appears to be more aggressive for distracted drivers with provisional licenses compared to drivers with open licenses. Abrupt or excessive braking by distracted drivers might pose significant safety concerns to following vehicles in a traffic stream.

Rescaling clustering trees using impact ratios for robust hierarchical speaker clustering

We present a novel method for improving hierarchical speaker clustering in the tasks of speaker diarization and speaker linking. In hierarchical clustering, a tree can be formed that demonstrates various levels of clustering. We propose a ratio that expresses the impact of each cluster on the formation of this tree and use this to rescale cluster scores. This provides score normalisation based on the impact of each cluster. We use a state-of-the-art speaker diarization and linking system across the SAIVT-BNEWS corpus to show that our proposed impact ratio can provide a relative improvement of 16% in diarization error rate (DER).

Demographic faultlines in boards : impact of diversity and board size

Negative board diversity-organizational outcomes research findings have highlighted the importance of studying board demographic faultlines. Based on research gaps, this study focuses on gender diversity, age diversity, board size and faultlines formation in corporate boards. It proposes a positive linear diversity-faultlines relationship based on self-categorization and social identity theories, interaction effects of gender diversity and age diversity on faultlines based on contingency theories, and a U-shaped board size-faultlines strength relationship. The hypotheses were tested in 288 large companies listed on the Australian Securities Exchange using archival data. The results provided partial support for the interaction effects relationships and support to the U-shaped board size-faultlines strength relationship. The findings indicate that boards with low levels of age diversity experience a negative linear relationship between gender diversity and faultlines such that higher representation of women leads to weaker faultlines. The results also suggest that small- and large-sized boards experience stronger faultlines strength than medium-sized board. These results inform practice and underline implications of board demographic diversity and board size.

Users’ perception of using web search engines and their impact on the perceived intention to reuse the systems

In today’s world of information-driven society, many studies are exploring usefulness and ease of use of the technology. The research into personalizing next-generation user interface is also ever increasing. A better understanding of factors that influence users’ perception of web search engine performance would contribute in achieving this. This study measures and examines how users’ perceived level of prior knowledge and experience influence their perceived level of satisfaction of using the web search engines, and how their perceived level of satisfaction affects their perceived intention to reuse the system. 50 participants from an Australian university participated in the current study, where they performed three search tasks and completed survey questionnaires. A research model was constructed to test the proposed hypotheses. Correlation and regression analyses results indicated a significant correlation between (1) users’ prior level of experience and their perceived level of satisfaction in using the web search engines, and (2) their perceived level of satisfaction in using the systems and their perceived intention to reuse the systems. A theoretical model is proposed to illustrate the causal relationships. The implications and limitations of the study are also discussed.

Impact of community pharmacist intervention discussing patients’ beliefs to improve medication adherence

Background Adherence to evidence based medicines in patients who have experienced a myocardial infarction remains low. Individual’s beliefs towards their medicines are a strong predictor of adherence and may influence other factors that impact on adherence. Objective To investigate if community pharmacists discussing patients’ beliefs about their medicines improved medication adherence at 12 months post myocardial infarction. Setting This study included 200 patients discharged from a public teaching hospital in Queensland, Australia, following a myocardial infarction. Patients were randomised into intervention (n = 100) and control groups (n = 100) and followed for 12 months. Method All patients were interviewed between 5 to 6 weeks, at 6 and 12 months post discharge by the researcher using the repertory grid technique. This technique was used to elicit the patient’s individualised beliefs about their medicines for their myocardial infarction. In the intervention group, patients’ beliefs about their medicines were communicated by the researcher to their community pharmacist. The pharmacist used this information to tailor their discussion with the patient about their medication beliefs at designated time points (3 and 6 months post discharge). The control group was provided with usual care. Main outcome measure The difference in non-adherence measured using a medication possession ratio between the intervention and control groups at 12 months post myocardial infarction. Results There were 137 patients remaining in the study (intervention group n = 72, control group n = 65) at 12 months. In the intervention group 29 % (n = 20) of patients were non-adherent compared to 25 % (n = 16) of patients in control group. Conclusion Discussing patients’ beliefs about their medicines for their myocardial infarction did not improve medication adherence. Further research on patients beliefs should focus on targeting non-adherent patients whose reasons for their non-adherence is driven by their medication beliefs.

The impact of litigation risk on the strategic timing of management earnings forecasts

This paper examines whether managers strategically time their earnings forecasts (MEFs) as litigation risk increases. We find as litigation risk increases, the propensity to release a delayed forecast until after the market is closed (AMC) or a Friday decreases but not proportionally more for bad news than for good news. Host costly this behaviour is to investors is questionable as share price returns do not reveal any under-reaction to strategically timed bad news MEF released AMC. We also find evidence consistent with managers timing their MEFs during a natural no-trading period to better disseminate information.

An observational analysis of the impact of board dynamics and directors’ participation on perceived board effectiveness

This study addresses calls for closer examination of board dynamics by offering an inside view of director interactions. Video-observations of three board meetings at each of two Australian corporations matched with director interviews and secondary data reveal distinct patterns of director interactions, their sources of variation and impact on perceived board effectiveness. Our data reveal that director interactions are multi-dimensional and dynamic: while group interactions across agenda items are similar, with a few directors leading the discussion, the contributing directors change across items. Moreover, directors’ inclusiveness and evenness of participation are associated with higher perceptions of board effectiveness. Last, we find that director interactions change with the nature of the items, board climate and board meeting arrangements. The study contributes to the literature by moving beyond the individual-level analysis of directors’ skills or independence, and offering a detailed view of how the joint group and individual dimensions of board dynamics affect board functioning.

Australian consumer attitudes and decision making on renewable energy technology and its impact on the transformation of the energy sector

This paper critically examines research on consumer attitudes and behavior towards solar photovoltaic (PV) and renewable energy technology in Australia. The uptake of renewable energy technology by residential consumers in Australia in the past decade has transformed the electricity supply and demand paradigm. Thus, this paper reviews Australian research on consumer behavior, understanding and choices in order to identify gaps in knowledge. As the role of the consumer transforms there is a critical need to understand the ways consumers may respond to future energy policies to mitigate unforeseen negative social and economic consequence of programs designed to achieve positive environmental outcomes.

Performance of new-generation portable water-filled road safety barriers under vehicular impact

Portable water-filled barriers (PWFB) are roadside structures used to enhance safety at roadside work-zones. Ideally, a PWFB system is expected to protect persons and objects behind it and redirect the errant vehicle. The performance criteria of a road safety barrier system are (i) redirection of the vehicle after impact and (ii) lateral deflection within allowable limits. Since its inception, the PWFB has received criticism due to its underperformance compared to the heavier portable concrete barrier. A new generation composite high energy absorbing road safety barrier was recently developed by the authors.

Pharmaceutical company influences on medication prescribing and their potential impact on quality use of medicines

Background Pharmaceuticals are big business, reporting strong market growth year after year. The ‘gatekeepers’ of this market are prescribers of medicines, who are the major target of pharmaceutical companies, utilizing direct and indirect influences. Methods This paper draws on previous research investigating pharmaceutical company prescribing influences to develop a qualitative model demonstrating the synergism between commercial influences on prescribing. The generic model was used to explore a realistic but hypothetical scenario to ascertain the applicability of the model. Results and Discussion A generic influence model was developed. The model was readily able to be adapted to reflect a realistic practice scenario. Conclusion Prescriber awareness of the linkages between various seemingly separate marketing techniques could potentially improve medicines usage in an evidence-based practice paradigm.