Multiple Imputation For Missing Ordinal Data

Simulations were used to compare complete case analysis of ordinal data with including multivariate normal imputations. MVN methods of imputation were not as good as using only complete cases. Bias and standard errors were measured against coefficients estimated from logistic regression and a standard data set

Design of the software development and verification system (SWDVS) for shuttle NASA study task 35

An overview of the Software Development and Verification System (SWDVS) for the space shuttle is presented. The design considerations, goals, assumptions, and major features of the design are examined. A scenario that shows three persons involved in flight software development using the SWDVS in response to a program change request is developed. The SWDVS is described from the standpoint of different groups of people with different responsibilities in the shuttle program to show the functional requirements that influenced the SWDVS design. The software elements of the SWDVS that satisfy the requirements of the different groups are identified

A Test-Retest Transition Matrix: A Modification of McNemar’s Test

McNemar introduced what is known today as a test for symmetry in a two by two contingency tables. The logic of the test is based on a sample of matched pairs with a dichotomous response. In our example, the sample consists of the scores before and after an education program and the responses before and after the program. Each pair of scores is from only one person. The pretest divides the group of responders according to their answers to a dichotomous question. The posttest divides the two groups into two groups of like labels. The result is a two by two table. We construct a test of homogeneity, where the proportion of initially partitioned subjects will be equally distributed over the same partition after the program is completed, conditioned on the initial distribution

On Treating A Survey Of Convenience Sample As A Simple Random Sample

Threat of bias has kept many from using data gathered in less than optimal conditions. We maintain that when convenience sampling represents race and gender at nearly correct proportions and can be beneficial, as these two variables are quite often used as stratification variables. We compared a convenience sample with a proven sample. Race and Sex were nearly proportional as was found in the proven sample. We conclude that the convenience sample can be used as though it is simple random

Adolescent distinctions between quality of life and self-rated health in quality of life research

BACKGROUND: In adult quality of life (QOL) research, the QOL construct appears to differ from self-rated health status. Although increased QOL continues to be recognized as an important outcome in health promotion and medical intervention, little research has attempted to explore adolescent perceptual differences between self-rated health and QOL. METHODS: Correlational analyses were performed between self-rated health, physical health days and mental health days, and QOL. Data were collected from two different public high school adolescent samples during two different time periods (1997 & 2003) in two different geographic regions in the USA (a southern & midwestern state) with two different sample sizes (N = 5,220 and N = 140, respectively) using the CDC Youth Risk Behavior Survey (YRBS). The Centers for Disease Control and Preventions' health-related quality of life scale (HRQOL) provided estimates of self-rated health, physical health days and mental health days, and QOL. RESULTS: All correlation coefficients were significant in both samples (p ≤ .0001), suggesting sample size was not a contributing factor to the significant correlations. In both samples, adolescent QOL ratings were more strongly correlated with the mean number of poor mental health days (r = .88, southern sample; r = .89, midwestern sample) than with the mean number of poor physical health days (r = .75, southern sample; r = .79, midwestern sample), consistent with adult QOL research. However, correlation coefficients in both samples between self-rated health and the mean number of poor physical health days was slightly smaller (r = .24, southern, r = .32, midwestern) than that between self-rated health and the mean number of poor mental health days (r = .25, southern, r = .39 midwestern), which is contrary to adult QOL research. CONCLUSION: Similar to adults, these results suggest adolescents are rating two distinct constructs, and that self-rated health and QOL should not be used interchangeably. QOL, in the context of public high school adolescents, is based largely upon self-reported mental health and to a lesser extent on self-reported physical health. Conversely, although self-reported mental health and self-reported physical health both contribute significantly to adolescent self-rated health, mental health appears to make a greater contribution, which is contrary to observations with adults. Health promoting efforts for adolescents may need to focus more on mental health than physical health, when considering population needs and type of micro or macro intervention

Racial Disproportionality as Experienced by Educators of Color: The Perceptions of Educators of Color with Respect to Their Pre-service Preparation

Thesis advisor: Lauri JohnsonEven before working in school as a teacher or administrator, many factors were influential in the preparation process. Given that the vast majority of teachers in the workforce come from traditional university education programs, the role that schools of education play in graduating people of color to enter the teaching force is important to examine. This qualitative case study sought to answer the following research question: What are the perceptions of educators of color with respect to their pre-service education preparation? This study falls within a broader study on the overall perceptions of educators of color with respect to the racial disproportionality and its impact on the educator pipeline and schools. Both from literature and the counter narratives of these educators of color, these topics emerged as salient: the racial diversity of universities and schools of education, the impact of barrier exams, the curriculum of schools of education, and the sense of belonging of people of color in universities and their schools of education. Semi-structured interviews with 12 educators of color in the Cityside Public Schools were examined through the lens of Critical Race Theory (CRT). Findings supported what was found in the literature regarding demographics in schools of education not favoring people of color, exams required to get into school of education being barriers, and people of color feeling disconnected from their universities in a number of ways. Further, participant interviews revealed the additional barrier posed by exams needed to gain teaching certification, the substantial value of connections at various points throughout the pre-service experience, and how important practicum and internship experiences are to aspiring educators.Thesis (EdD) — Boston College, 2018.Submitted to: Boston College. Lynch School of Education.Discipline: Educational Leadership and Higher Education

The white matter connectome as an individualized biomarker of language impairment in temporal lobe epilepsy.

ObjectiveThe distributed white matter network underlying language leads to difficulties in extracting clinically meaningful summaries of neural alterations leading to language impairment. Here we determine the predictive ability of the structural connectome (SC), compared with global measures of white matter tract microstructure and clinical data, to discriminate language impaired patients with temporal lobe epilepsy (TLE) from TLE patients without language impairment.MethodsT1- and diffusion-MRI, clinical variables (CVs), and neuropsychological measures of naming and verbal fluency were available for 82 TLE patients. Prediction of language impairment was performed using a robust tree-based classifier (XGBoost) for three models: (1) a CV-model which included demographic and epilepsy-related clinical features, (2) an atlas-based tract-model, including four frontotemporal white matter association tracts implicated in language (i.e., the bilateral arcuate fasciculus, inferior frontal occipital fasciculus, inferior longitudinal fasciculus, and uncinate fasciculus), and (3) a SC-model based on diffusion MRI. For the association tracts, mean fractional anisotropy was calculated as a measure of white matter microstructure for each tract using a diffusion tensor atlas (i.e., AtlasTrack). The SC-model used measurement of cortical-cortical connections arising from a temporal lobe subnetwork derived using probabilistic tractography. Dimensionality reduction of the SC was performed with principal components analysis (PCA). Each model was trained on 49 patients from one epilepsy center and tested on 33 patients from a different center (i.e., an independent dataset). Randomization was performed to test the stability of the results.ResultsThe SC-model yielded a greater area under the curve (AUC; .73) and accuracy (79%) compared to both the tract-model (AUC: .54, p < .001; accuracy: 70%, p < .001) and the CV-model (AUC: .59, p < .001; accuracy: 64%, p < .001). Within the SC-model, lateral temporal connections had the highest importance to model performance, including connections similar to language association tracts such as links between the superior temporal gyrus to pars opercularis. However, in addition to these connections many additional connections that were widely distributed, bilateral and interhemispheric in nature were identified as contributing to SC-model performance.ConclusionThe SC revealed a white matter network contributing to language impairment that was widely distributed, bilateral, and lateral temporal in nature. The distributed network underlying language may be why the SC-model has an advantage in identifying sub-components of the complex fiber networks most relevant for aspects of language performance

Potential economic impacts from improving breastfeeding rates in the UK

This article has been made available through the Brunel Open Access Publishing Fund.RATIONALE: Studies suggest that increased breastfeeding rates can provide substantial financial savings, but the scale of such savings in the UK is not known. OBJECTIVE: To calculate potential cost savings attributable to increases in breastfeeding rates from the National Health Service perspective. DESIGN AND SETTINGS: Cost savings focussed on where evidence of health benefit is strongest: reductions in gastrointestinal and lower respiratory tract infections, acute otitis media in infants, necrotising enterocolitis in preterm babies and breast cancer (BC) in women. Savings were estimated using a seven-step framework in which an incidence-based disease model determined the number of cases that could have been avoided if breastfeeding rates were increased. Point estimates of cost savings were subject to a deterministic sensitivity analysis. RESULTS: Treating the four acute diseases in children costs the UK at least £89 million annually. The 2009-2010 value of lifetime costs of treating maternal BC is estimated at £959 million. Supporting mothers who are exclusively breast feeding at 1 week to continue breast feeding until 4 months can be expected to reduce the incidence of three childhood infectious diseases and save at least £11 million annually. Doubling the proportion of mothers currently breast feeding for 7-18 months in their lifetime is likely to reduce the incidence of maternal BC and save at least £31 million at 2009-2010 value. CONCLUSIONS: The economic impact of low breastfeeding rates is substantial. Investing in services that support women who want to breast feed for longer is potentially cost saving

An Australian Survey of Current Prescribing Practices of Methotrexate in Rheumatoid Arthritis

A 15-item questionnaire was distributed by Australia Post between October-December 1992, to Australian rheumatologists. The sample was ascertained from the Australian Rheumatology Association (ARA) Directory. Any ARA registrant whose practice was limited strictly to paediatrics or non clinical research, e.g. immunology, was excluded. A total of 180 eligible practising rheumatologists was identified. Second and third mailings of the questionnaire were made to non-respondents at intervals of about one month. The analysis was based mainly on descriptive statistics