A human performance evaluation of airborne-detected windshear display

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1994.Includes bibliographical references (leaves 87-88).by Mark T. Salzberger.M.S

Reducing outcome measures in mental health: a systematic review of the methods

Economic and Social Research Council (ESRC) Grant number ES/J500057/1 and South London and Maudsley NHS Trust

Shedding light on the elusive role of endothelial cells in cytomegalovirus dissemination.

Cytomegalovirus (CMV) is frequently transmitted by solid organ transplantation and is associated with graft failure. By forming the boundary between circulation and organ parenchyma, endothelial cells (EC) are suited for bidirectional virus spread from and to the transplant. We applied Cre/loxP-mediated green-fluorescence-tagging of EC-derived murine CMV (MCMV) to quantify the role of infected EC in transplantation-associated CMV dissemination in the mouse model. Both EC- and non-EC-derived virus originating from infected Tie2-cre(+) heart and kidney transplants were readily transmitted to MCMV-naïve recipients by primary viremia. In contrast, when a Tie2-cre(+) transplant was infected by primary viremia in an infected recipient, the recombined EC-derived virus poorly spread to recipient tissues. Similarly, in reverse direction, EC-derived virus from infected Tie2-cre(+) recipient tissues poorly spread to the transplant. These data contradict any privileged role of EC in CMV dissemination and challenge an indiscriminate applicability of the primary and secondary viremia concept of virus dissemination

Improving the measurement of oral health-related quality of life: Rasch model of the oral health impact profile-14

Objectives: The 14-item Oral Health Impact Profile (OHIP-14) is the most frequently used instrument to measure oral health-related quality-of-life (OHRQoL) in adults. Despite its popularity, its psychometric properties have been predominantly investigated based on the classical test theory while the fundamental principles of measurement have not been fully assessed. Therefore, our aim was to investigate to what extent the OHIP-14 meets the fundamental requirments of measurements. Methods: We used the Rasch model to explore person-item-targeting, unidimensionality, local independence of items, invariance (differential-item-functioning, DIF), and the order of thresholds between response-options in the German version OHIP-14. We used data from osteoarthritis patients because hand disabilities and joint pain might influence oral hygiene. Furthermore, osteoarthritis in the temporomandibular-joint directly affects oral functioning. Results: Five-hundred sixteen patients were included (mean age 66.5 years [+/- 10.2; ranging from 34 to 89]; 71.3% [368] females). The OHIP-14 median total score was 0 (interquartile-range from 0 to 4), indicating a right-skewed distribution because many patients reported good OHRQoL. The instrument was found unidimensional. However, there was strong evidence of local dependency, disordered thresholds between responseoptions, and age-related DIF for item 5. A revised scoring scheme with three instead of five answer-options in all items and eliminating two items resolving local dependency, the newly adapted OHIP-12, showed better reliability and item-fit to the Rasch model than the original OHIP-14. Conclusions: This study assesses, for the first time, the OHIP-14 in terms of fundamental principles of measurement and proposes an item-reduced OHIP-12 as a psychometrically more accurate version of the instrument. Clinical significance: The Rasch model is essential to ensure instruments' precision and clinical meaningfulness when measuring OHRQoL in clinical practice and research. The OHIP-12, derived from the OHIP-14 by deleting two items due to local dependency, with a revised scoring scheme for all items distinguishing three answeroptions instead of five, represents a psychometrically improved version of the instrument.Clinical epidemiolog

Rasch model of the child perceptions questionnaire in multi-country data

Objective To be fit-for-purpose, oral health-related quality of life instruments must possess a range of psychometric properties which had not been fully examined in the 16-item Short Form Child Perceptions Questionnaire for children aged 11 to 14 years (CPQ11-14 ISF-16). We used advanced statistical approaches to determine the CPQ’s measurement accuracy, precision, invariance and dimensionality and analyzed whether age range could be extended from 8 to 15 years. Methods Fit to the Rasch model was examined in 6648 8-to-15-year-olds from Australia, New Zealand, Brunei, Cambodia, Hong Kong, Malaysia, Thailand, Germany, United Kingdom, Brazil and Mexico. Results In all but two items, the initial five answer options were reduced to three or four, to increase precision of the children’s selection. Items 10 (Shy/embarrassed) and 11 (Concerned what others think) showed an ‘extra’ dependency between item scores beyond the relationship related to the underlying latent construct represented by the instrument, and so were deleted. Without these two items, the CPQ was unidimensional. The three oral symptoms items (4 Food stuck in teeth, 3 Bad breath and 1 Pain) were required for a sufficient person-item coverage. In three out of 14 items (21 %), Europe and South America showed regional differences in the patterns of how the answer options were selected. No differential item functioning was detected for age. Conclusion Except for a few modifications, the present analysis supports the combination of items, the cross-cultural validity of the CPQ with 14 items and the extension of the age range from 8 to 15 years. Clinical significance The valid, reliable, shortened and age-extended version of the CPQ resulting from this study should be used in routine care and clinical research. Less items and a wider age range increase its usability. Symptoms items are needed to precisely differentiate between children with higher and lower quality of life

Applying the revised Chinese Job Content Questionnaire to assess psychosocial work conditions among Taiwan's hospital workers

<p>Abstract</p> <p>Background</p> <p>For hospital accreditation and health promotion reasons, we examined whether the 22-item Job Content Questionnaire (JCQ) could be applied to evaluate job strain of individual hospital employees and to determine the number of factors extracted from JCQ. Additionally, we developed an Excel module of self-evaluation diagnostic system for consultation with experts.</p> <p>Methods</p> <p>To develop an Excel-based self-evaluation diagnostic system for consultation to experts to make job strain assessment easier and quicker than ever, Rasch rating scale model was used to analyze data from 1,644 hospital employees who enrolled in 2008 for a job strain survey. We determined whether the 22-item Job Content Questionnaire (JCQ) could evaluate job strain of individual employees in work sites. The respective item responding to specific groups' occupational hazards causing job stress was investigated by using skewness coefficient with its 95% CI through item-by-item analyses.</p> <p>Results</p> <p>Each of those 22 items on the questionnaire was examined to have five factors. The prevalence rate of Chinese hospital workers with high job strain was 16.5%.</p> <p>Conclusions</p> <p>Graphical representations of four quadrants, item-by-item bar chart plots and skewness 95% CI comparison generated in Excel can help employers and consultants of an organization focusing on a small number of key areas of concern for each worker in job strain.</p