Warfarin has well-proven benefit (stroke prevention) but an associated increase in harm (major bleeding) in patients with atrial fibrillation (AF). Current clinical prediction rules (CPRs) are limited in that stroke CPRs predict only the probabilities of “stroke” and “no stroke” and bleeding CPRs predict only “bleed” and “no bleed” despite the fact that outcomes actually include combinations of these four groups. The study objective was to evaluate methods to create a CPR that calculates individual patient probabilities of warfarin’s four combined benefit/harm outcome groups: i) no stroke/no bleed; ii) no stroke/bleed; iii) stroke/no bleed; iv) stroke/bleed. Methods: Patient-level data were analyzed from a randomized controlled trial database (n=9,155) and an observational anticoagulant clinic database (n=5,475) from start of trial or time of AF diagnosis respectively (baseline), until end of follow-up. Patients were stratified into the four groups based on their outcomes during follow-up. Due to high mortality in both datasets, death was included as an outcome. Decision tree modeling and polytomous logistic regression (PLR) were conducted to identify baseline patient factors predicting each outcome group. Results: Based on a literature review of recent high quality RCTs, benefit and harm are reported separately and not at a more individualized level than subgroup analysis. In this individualized combined benefit/harm analysis, both PLR and decision tree modeling identified predictors of no stroke/no bleed, no stroke/bleed, stroke/no bleed and death without a prior stroke or bleed. PLR results predicted probabilities of combined benefit/harm outcomes for every patient but required detailed computation. However, results could potentially be converted into automated form for ease of use. Decision trees provided a visual algorithm approach to risk assessment but did not i) predict the probability of warfarin’s combined benefit/harm outcomes based on all predictors simultaneously, ii) predict the probability of these outcomes for every patient or iii) provide statistical parameters of predictive value (odds ratios). Conclusions: The PLR technique could be used to predict patient probabilities of combined benefit/harm outcomes with warfarin. The study results require validation, preferably prospectively, in other cohorts. If validated, this approach should be tested to determine if it aids patient decision-making.

Ammonia refrigeration systems are widely used in industry. Demand of these systems is expected to increase due to the advantages of ammonia as refrigerant and because ammonia is considered a green refrigerant. Therefore, it is important to evaluate the risks in existing and future ammonia refrigeration systems to ensure their safety. LOPA (Layer of Protection Analysis) is one of the best ways to estimate the risk. It provides quantified risk results with less effort and time than other methods. LOPA analyses one cause-consequence scenario per time. It requires failure data and PFD (Probability of Failure on Demand) of the independent protection layers available to prevent the scenario. Complete application of LOPA requires the estimation of the severity of the consequences and the mitigated frequency of the initiating event for risk calculations. Especially in existing ammonia refrigeration systems, information to develop LOPA is sometimes scarce and uncertain. In these cases, the analysis relies on expert opinion to determine the values of the variables required for risk estimation. Fuzzy Logic has demonstrated to be useful in this situation allowing the construction of expert systems. Based on fuzzy logic, the LOPA method was adapted to represent the knowledge available in standards and good industry practices for ammonia refrigeration. Fuzzy inference systems were developed for severity and risk calculation. Severity fuzzy inference system uses the number of life threatening injuries or deaths, number of injuries and type of medical attention required to calculate the severity risk index. Frequency of the mitigated scenario is calculated using generic data for the initiating event frequency and PFD of the independent protection layers. Finally, the risk fuzzy inference system uses the frequency and severity values obtained to determine the risk of the scenario. The methodology was applied to four scenarios. Risk indexes were calculated and compared with the traditional approach and risk decisions were made. In conclusion, the fuzzy logic LOPA method provides good approximations of the risk for ammonia refrigeration systems. The technique can be useful for risk assessment of existing ammonia refrigeration systems.

Abstract This study concerns contents of several organotin compounds, monobutyltin (MBT), dibutyltin (DBT), tributyltin (TBT), monophenyltin (MPhT), diphenyltin (DPhT) and triphenyltin (TPhT), in seafood. Seafood samples were collected from markets and coastal zone in Taiwan, and contents of organotins were analyzed by Grignard reagent derivation coupled with GC/FPD. Besides, the tolerable daily intake (TDI) of (TBT+DBT), mean body weight of Taiwan citizen and the consumption of seafood were used to derive the tolerable average residue level (TARL) of the compounds. The risk assessment was implemented by comparing the content to TARL. The contents of TBT, DBT, MBT, TPhT, DPhT and MPhT in seafood ranged N. D~48.36 ng Sn/g wet wt., N. D~36.68 ng Sn/g wet wt., N. D~79.19 ng Sn/g wet wt., N. D~225.53 ng Sn/g wet wt., N. D~128.16 ng Sn/g wet wt., N. D ~ 95.44 ng Sn/g wet wt., respectively. Reference survey showed that mean body weight of Taiwan citizen is 54.42 Kg, and seafood consumption rate is 127.59 g/day/person. A TARL of 44.27 ng Sn/g wet wt. is derived accordingly. Of all the 71 samples, only 4 contain more (TBT+DBT) than the TARL. On the other hand, (TBT+DBT) contents weighed by consumed ratio averaged 3.87 ng Sn/g wet wt., which is far under the TARL. Different visions lead to the same conclusion that (TBT+DBT) content of seafood in Taiwan is far away from dangerous level. This study also concluded that cooking process doesn¡¦t affect the contents of organotin compounds of seafood, and the Grignard reagents contribute to the TBT blank signal. Furthermore, the independence between organotins and factors such as classifications, sampling area or habitat was discussed.

Thesis (Ph. D.)--Ohio State University, 2003. / Title from first page of PDF file. Document formatted into pages; contains xvi, 239 p.; also includes graphics (some col). Includes abstract and vita. Advisor: Sherman D. Hanna, College of Human Ecology. Includes bibliographical references (p. 230-239).

Water as a route of opportunistic bacterial disease transmission has not been well established. The use of epidemiological evidence linking drinking water bacterial contamination to health effects in a population is lacking and very costly to obtain. Also, the significance of exposure to low-level contamination is difficult to determine epidemiologically. This makes it difficult to estimate the impact on a community. The use of risk assessment approach allows an understanding of low-level exposure; and to define it in a more quantitative fashion. Microbial risk assessment was employed to determine the risks associated with exposure to selected opportunistic bacterial pathogens (Aeromonas hydrophila and Pseudomonas aeruginosa) present in drinking water from various sources. An extensive analysis was conducted on drinking water obtained from various sources including point-of-use (POU)-treated water, tap water with POUconnection, tap water, bottled water, and water from vending machines and storage tanks. Enumerated bacteria included: A. hydrophila, heterotrophic plate count (HPC) bacteria, Mycobacteriuni spp., Plesiomonas shigelloides, P. aeruginosa, and total and fecal coliforms. It was found that opportunistic pathogens were present in small numbers in drinking water. Neither fecal coliforms nor P. shigelloides were found in the drinking water samples. The annual risks of colonization based on the consumption of 2L/day/person for drinking water were determined to be as high as 7.9x10⁻⁵ and 9.9x10⁻⁴ for A. hydrophila and P. aeruginosa, respectively at exposure levels ranging from 90 to 10 CFliimL. respectively. The results obtained indicates that the risk of colonization is a transient process, and the probability of infection may be very but could result in the most vulnerable (very young, the elderly and immunocompromised). More studies are needed on the occurrence of opportunistic pathogens in drinking water from various sources and animal andjor human feeding studies to better define dose-response in both healthy and immunocomprimised individuals. There is no doubt that the greatest need for microbial risk assessment is the occurrence data. Therefore, national surveys in drinking water from various sources will help in the developing of microbial risk assessment for opportunistic bacterial pathogens. The use of conventional methods as well as molecular approaches are recommended in order to obtain a more accurate identification of waterborne bacterial pathogens.

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Despite the overwhelming amount of research conducted on forensic risk assessments in the last twenty years there has been a distinct lack of information on the use of the professional override to adjust actuarial scores. The current study was designed to fill the gap in the research literature examining the effects from using the professional override in the Level of Service Inventory – Ontario Revision (LSI-OR). While there has been recent research conducted indicating that overrides or adjusted actuarial risk assessments are not as accurate as purely actuarial methods (Gore, 2007; Hanson et al., 2007; Hogg, 2011; Wormith, Hogg, & Guzzo, 2012) there is a lack of research conducted solely on the use of professional overrides in forensic risk assessment. This study analysed data from 40,539 provincial offenders in Ontario, Canada. The sample was primarily male (83.9%), White (63.0%), and was comprised of violent (53.0%), sexual (3.3%), and non-violent offenders (43.7%). Predictive validity analyses were conducted to determine the effects of the override for the total sample and then stratified by gender and ethnicity. Special attention was paid to the effects of the override compared between violent, sexual, and non-violent offenders. Results showed that the General Risk/Need score was most strongly correlated with non-violent recidivism over violent and sexual recidivism and that the General Risk/Need was significantly more correlated with non-violent recidivism for female offenders compared to male offenders. Correlation analyses showed that the initial risk levels appeared to be better predictors of general, violent, and non-violent recidivism whereas the final risk levels appeared to be better predictors of sexual recidivism in some cases. For violent and sexual offenders, the initial risk levels were significantly stronger predictors of general, violent, and non-violent recidivism than the final risk levels yet the final risk levels were non-significantly stronger predictors of sexual recidivism. There were no significant differences between the initial and final risk levels’ prediction estimates of the recidivism outcomes for non-violent offenders. Further, there were many more overrides used to increase risk levels than to decrease risk levels overall; sexual offenders had more overrides used to increase risk levels than violent and non-violent offenders combined. Risk level matrices indicated that there were many discrepancies between the number of offenders overridden and their corresponding recidivism rates. Regression analyses indicated additional discrepancies between the significant predictors of recidivism and the significant predictors of the override. Though there were certain methodological limitations to the current study the results still provide important information on the use of the override in a sample of male and female Ontario offenders. The results showed that the override resulted in decreased predictive validity of multiple recidivism outcomes. The conflicting information between the prediction of sexual recidivism and general, violent, or non-violent recidivism prevents a clear message being drawn from this study, yet the equivocal results provide further doubt and criticism of the use of adjusted actuarial practices in forensic risk assessment. Training assessors for how to use the override and examinations of the effects of the override for various offender groups must be improved and more frequently monitored. Further research should also focus on the reasons why overrides are used and if there are any biases concerning certain offender types. Misuse of the override has far-reaching ethical and legal implications that must be limited to ensure the future of forensic risk assessment is as accurate and appropriate as possible.

No description available.

Thesis (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Political Science, 2007. / Title from title screen (viewed on Feb 5, 2008). Includes bibliographical references (p. 99-103).