A Comparison of Rectangular vs. Circular Radiographic Collimation During Simulated Endodontic Therapy

Rectangular collimation is used in dentistry to reduce radiation by restricting the x-ray beam to approximately the size of a number 2 intraoral film (3.2X4.1 cm). However, this restricted beam size can lead to exposure errors. The aim of this study was to retrospectively evaluate the number of radiographs exposed and the presence of technical errors by the use of traditional circular or rectangular collimators during endodontic therapy on simulated teeth in manikins. A total of 1475 digital radiographs of 84 teeth exposed by 60 dental students were evaluated. Evaluation was done by a board certified endodontist, an endodontic resident, and a dental student. Analysis of the different raters showed no significant differences among the three. Radiographs were randomized and blindly renamed. Repeated-measures mixed-model ANOVA was used to compare the number of radiographs exposed using the different collimators. Although not statistically significant (P\u3c.05), there were 15% more radiographs taken with the rectangular collimator when compared to the circular collimator. Using a repeated-measures logistic regression, there was a significant difference of the proportion of radiographs with cone cuts (P = .0003) taken with a rectangular collimator (59%) compared to radiographs taken with a circular collimator (19%). There was no significant evidence for a collimator difference when considering missed apex (P = .0986) or missed apex due to a cone cut (P = .0631). In order to expose high quality radiographs avoiding cone cuts, a traditional circular collimator may be indicated for use during endodontic therapy

Proposal for Management and Control of Intermodal Containers Using Monte Carlo Simulation

When examining the increased attention in freight transportation, a necessity for sustainable and efficient transportation system appears. The presence of road and traffic complications as well as environmental concerns forces us to develop or adapt an alternative operational system that allows us to overcome these issues. Moreover, the escalation in fuel prices in addition to driver issues for road-only haulage forms an unprofitable and unreliable approach. In this on-going MBA project, container management issues are addressed. A number of delays and their casuals are discussed and analysed. Moreover a Monte Carlo simulation framework is proposed to be used to analyse the interaction of different loading and unloading resources and containers within intermodal container management

The relationship between non-standard work arrangements and injuries in Europe

Abstract Background: Non-standard work arrangements are becoming an increasingly important determinant of health and safety among workers. The main objective of this study is to examine the relationship between indicators of non-standard work arrangements including precarious contract, long working hours, multiple jobs, shift work, and occupational injuries, using a representative European sample and taking into account several sociodemographic and work characteristics. Methods: The study was based on the data of the fifth European Working Conditions Survey (EWCS). For the purpose of this analysis, the sample was restricted to 26839 respondents from the 27 countries of the European Union, who were all employed workers. Associations between non-standard work arrangements and occupational injuries were studied with multilevel modeling techniques while adjusting for several confounders. Results: About 8.44% of the workers suffered from an occupational injury. Multivariate regression model showed an increased injury risk for those working long hours (OR 1.29, 95% CI 1.15 - 1.44), having multiple jobs (OR 1.23, 95% CI 1.03 - 1.47) and shift work (OR 1.35, 95% CI 1.18 - 1.54). The relationship between contract type and occupational injuries was not significant (OR 0.91, 95% CI 0.78 - 1.07). No significant gender difference was observed. Conclusion: This study confirms that indicators of non-standard work arrangements, except for precarious contract type, were significantly associated with occupational injuries. To reduce the burden of occupational injuries, not only risk reduction strategies and interventions are needed but also policy efforts at European level should be undertaken to limit non-standard work arrangements