27,336 research outputs found
Potential Hazards of Orthodontic Treatment – What Your Patient Should Know
Orthodontic treatment carries with it the risks of tissue damage, treatment failure and an increased predisposition to dental disorders. The dentist must be aware
of these risks in order to help the patient make a fully informed choice whether to proceed with orthodontic treatment. This paper outlines the potential hazards and
suggests how they may be avoided or minimized
Does articulating study casts make a difference to treatment planning?
OBJECTIVE: To assess whether articulating casts in centric relation (CR) compared with intercuspal
position (ICP) makes a difference to treatment planning.
Design: Reliability analysis.
Subjects: Ten orthodontists.
METHODS: Twenty case vignettes were examined on three occasions: twice with the casts in ICP
and once in CR. A series of dichotomous decisions were made relating to the treatment need and
treatment mechanics.
MAIN OUTCOME MEASURES: The changes in treatment decisions were examined. Intra-examiner
agreement between the two hand-held cast assessments (H1 v. H2) and between the first set of
hand-held casts compared with the articulated casts (H1 v. A1) were evaluated using the kappa
statistic. The differences between the kappa statistics for H1 v. H2 and H1 v. A1 were then tested
with the Wilcoxon matched pairs signed rank sum test.
RESULTS: The only statistically significant change in the kappa score between H1 v. H2 and H1 v.
A1 was for the extraction decision (P 0.007). No other statistically significant differences were
found for the other treatment decisions, although trends were identified for orthognathic
surgery and anchorage support decisions.
CONCLUSION: Routine articulation of study models for all orthodontic patients is not supported
by the results of this study. Articulation of the study models did not affect the treatment planning
decisions in a meaningful manner. Further work with selected samples is required to
determine if articulation is helpful for specific malocclusions
Stock assessment of Lates niloticus (L.), Oreochromis niloticus (L.) and Rastrineobola argentea (Pellegrin) using fisheries-dependent data from Tanzania waters of Lake Victoria
Three commercially important fish species, Lates niloticus (L.), Rastrineobola argentea (Pellegrin) and Oreochromis niloticus (L.) that are fished by artisanal fishermen of Lake Victoria, Tanzania part, were studied in Kagera, Mwanza and Mara beaches from October 1997 to July 1999. Catches, effort, exploitation and stock structure were investigated. Beaches for sampling were selected based on importance for landing the above named fish species. The number of boats found on beach that day, the number that lay idle and their means of propulsion were recorded. As many boats as possible were sampled for gear type and gear size. The catches were sorted into species and measured. Variation in the species and size composition of landings was observed between regions, between months and between gears used. The implications of the findings to management are discussed
Cognitive finance: Behavioural strategies of spending, saving, and investing.
Research in economics is increasingly open to empirical results. The advances in behavioural approaches are expanded here by applying cognitive methods to financial questions. The field of "cognitive finance" is approached by the exploration of decision strategies in the financial settings of spending, saving, and investing. Individual strategies in these different domains are searched for and elaborated to derive explanations for observed irregularities in financial decision making. Strong context-dependency and adaptive learning form the basis for this cognition-based approach to finance. Experiments, ratings, and real world data analysis are carried out in specific financial settings, combining different research methods to improve the understanding of natural financial behaviour. People use various strategies in the domains of spending, saving, and investing. Specific spending profiles can be elaborated for a better understanding of individual spending differences. It was found that people differ along four dimensions of spending, which can be labelled: General Leisure, Regular Maintenance, Risk Orientation, and Future Orientation. Saving behaviour is strongly dependent on how people mentally structure their finance and on their self-control attitude towards decision space restrictions, environmental cues, and contingency structures. Investment strategies depend on how companies, in which investments are placed, are evaluated on factors such as Honesty, Prestige, Innovation, and Power. Further on, different information integration strategies can be learned in decision situations with direct feedback. The mapping of cognitive processes in financial decision making is discussed and adaptive learning mechanisms are proposed for the observed behavioural differences. The construal of a "financial personality" is proposed in accordance with other dimensions of personality measures, to better acknowledge and predict variations in financial behaviour. This perspective enriches economic theories and provides a useful ground for improving individual financial services
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Seismic design of reinforced concrete frames for minimum embodied CO2 emissions
Optimum structural design of reinforced concrete (RC) frames has been the focus of extensive research. Typically, previous studies set economic cost as the main design objective despite the fact that RC structures are major contributors of CO2 emissions. The limited number of studies examining optimum design of RC frames for minimum CO2 emissions do not address seismic design considerations. However, in many countries around the world, including most of the top-10 countries in CO2 emissions from cement production, RC structures must be designed against earthquake threat. To bridge this gap, the present study develops optimum seismic designs of RC frames for minimum cradle to gate embodied CO2 emissions and compares them with optimum designs based on construction cost. The aim is to identify efficient design practices that minimize the environmental impact of earthquake-resistant RC frames and examine the trade-offs between their cost and CO2 footprint. To serve this goal, an RC frame is optimally designed according to all ductility classes of Eurocode 8 and for various design peak ground accelerations (PGAs), concrete classes and materials embodied CO2 footprint scenarios. It is found that the minimum feasible CO2 emissions of RC frames strongly depend on the adopted ductility class in regions of high seismicity, where low ductility seismic design can generate up to 60% more CO2 emissions than designs for medium and high ductility. The differences reduce, however, as the level of seismicity decreases. Furthermore, CO2 emissions increase significantly with the design PGA. On the other hand, they are less sensitive to the applied concrete class. It is also concluded that, for medium to high values of the ratio of the unit environmental impact of reinforcing steel to the respective impact of concrete, the minimum CO2 seismic designs are very closely related to the minimum cost designs. However, for low values of the same ratio, the minimum cost design solutions can generate up to 13% more emissions than the minimum CO2 designs
Perception of VMS Effectiveness: A British and Canadian Perspective
Variable Message Signs are becoming a common sight on the UK Motorway network and have been well established on North American Freeways for several decades, as highway authorities strive to better manage scarce road network resources and provide travellers with up-to-date traffic information and alternative route options. The flexibility of VMS allows them to display varied information on road conditions, safety messages, alternate routes, speed limits, and general travel information. The steady growth in deployment of VMS in the next few years will lead to enhanced use of information to better manage highways and control levels of traffic congestion. The effectiveness of VMS in achieving this goal, however, depends entirely upon driver response to and perception of the information displayed.
Previous research has indicated that VMS information needs to be timely, accurate, easily understandable and also believable for motorists to take any notice of it and act accordingly. This paper will report on findings from several attitudinal questionnaire surveys, conducted in and around London and Manchester in the UK, and Toronto in Canada, to determine VMS effectiveness. The studies focus on driver perception of the effectiveness of different types of information displayed and drivers’ preferences for future information provision
Molar band re-use and decontamination: a survey of specialists
Objective: To determine the pattern of use and re-use of orthodontic molar bands, and examine infection control measures in a sample of UK orthodontists.
Design: Questionnaire survey.
Subjects and methods: Questionnaires were sent to 204 individuals selected at random from the UK Specialist Orthodontist list. Follow-up questionnaires were sent to those that had not replied within 8 weeks. An overall response rate of 74.5% was achieved.
Main outcome measures: Orthodontic band use and re-use and cross-infection control.
Results: The reported rates of pre-sterilization cleaning and sterilization of orthodontic instruments were 92 and 100%, respectively. Of the respondents, 90% were using bands for molar teeth with the remainder routinely used bonded attachments. Most clinicians (95%) using bands routinely re-used them after being tried-in with 5% discarding them. Pre-sterilization cleaning of re-used molar bands was carried out by 92% of respondents who reclaimed bands. Sterilization of these bands was then carried out by most specialists apart from 2.
Conclusions: The majority of UK specialist orthodontists who responded to the questionnaire are adhering to universal precautions for cross-infection control and are carrying out approved decontamination procedures. The majority are also reusing orthodontic bands that have been tried in the mouth, but found to be the wrong size. The great diversity of reported procedures for decontamination of instruments and bands suggest that more research is required to provide guidelines into the most effective method
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