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180 results on '"Begg, Melissa D."'

13. A comparison of regression approaches for analyzing clustered data

Author

Desai, Manisha and Begg, Melissa D.

Subjects
Public health -- Research, Methodology -- Analysis, Government, Health care industry
Abstract

Objectives. We used 3 approaches to analyzing clustered data to assess the impact of model choice on interpretation. Methods. Approaches 1 and 2 specified random intercept models but differed in standard versus novel specification of covariates, which impacts ability to separate within- and between-cluster effects. Approach 3 was based on standard analysis of paired differences. We applied these methods to data from the National Collaborative Perinatal Project to examine the association between head circumference at birth and intelligence (IQ) at age 7 years. Results. Approach 1, which ignored within- and between-family effects, yielded an overall IQ effect of 1.1 points (95% confidence interval [CI]=0.9, 1.3) for every 1-cm increase in head circumference. Approaches 2 and 3 found comparable within-family effects of 0.6 points (95% C1=0.4, 0.9) and 0.69 points (95% C1=0.4, 1.0), respectively. Conclusions. Our findings confirm the importance of applying appropriate analytic methods to clustered data, as well as the need for careful covariate specification in regression modeling. Method choice should be informed by the level of interest in cluster-level effects and item-level effects.

Published
2008

14. Serologic evidence of prenatal influenza in the etiology of schizophrenia

Author

Brown, Alan S., Begg, Melissa D., Gravenstein, Stefan, Schaefer, Catherine A., Wyatt, Richard J., Bresnahan, Michaeline, Babulas, Vicki P., and Susser, Ezra S.

Subjects
Fetal diseases -- Complications and side effects, Schizophrenia -- Research, Schizophrenia -- Risk factors, Health, Psychology and mental health
Published
2004

19. Paternal Age and Risk of Schizophrenia in Adult Offspring

Author

Brown, Alan S., Schaefer, Catherine A., Wyatt, Richard J., Begg, Melissa D., Goetz, Raymond, Bresnahan, Michaeline A., Harkavy-Friedman, Jill, Gorman, Jack M., Malaspina, Dolores, and Susser, Ezra S.

Published
2002

28. Enhanced reverse transcriptase-polymerase chain reaction for prostate specific antigen as an indicator of true pathologic stage in patients with prostate cancer

Author

Katz, Aaron E., de Vries, Glen M., Begg, Melissa D., Raffo, Anthony J., Cama, Cristoforo, O'Toole, Kathleen, Buttyan, Ralph, Benson, Mitchell C., and Olsson, Carl A.

Subjects
Prostate cancer -- Diagnosis, Tumor staging -- Methods, Prostate-specific antigen -- Testing, Health
Abstract

Background. As up to 50% of all patients with prostate cancer who have undergone radical prostatectomy are found to be understaged subsequent to surgery, a more sensitive early staging modality currently is needed. A molecular assay that detects prostate specific antigen (PSA)-synthesizing cells in the peripheral circulation of patients with prostate cancer is described. Methods. An enhanced reverse-transcriptase polymerase chain reaction (RT-PCR) assay specific for PSA mRNA was performed on RNA extracted from blood drawn from 94 patients before radical prostatectomy. Surgical specimens were examined to determine the extent of tumor spread. The assay was compared with imaging modalities, digital rectal examination, and serum PSA level as predictors of pathology. Additionally, patients were monitored postoperatively by serum PSA level to determine any potential correlation between patient RT-PCR scores and subsequent tumor recurrence. Results. Postoperative pathology revealed that 36 of the 94 patients had extraprostatic disease at the time of surgery. Enhanced RT-PCR identified 26 of these patients from preoperative blood specimens (72% sensitivity). The test was negative for 51 of the 58 patients with organ-confined disease (88% specificity). An odds ratio analysis showed that no other preoperative staging modality was related more strongly to extraprostatic or organ-confined disease. Follow-up PSA determinations revealed that RT-PCR positive patients were at higher risk for a recurrence. At 6 months after surgery, the rates for an increased PSA were 19 and 2% for RT-PCR-positive and -negative patients, respectively. Conclusions. The data from this follow-up study continue to support the utility of enhanced RT-PCR as an early staging modality for radical prostatectomy candidates. Cancer 1995; 75:1642-8.

Published
1995

29. Serum prolactin levels in homosexuals and bisexual men with HIV infection

Author

Gorman, Jack M., Warne, Patricia A., Begg, Melissa D., Cooper, Thomas B., Novacenko, Hana, Williams, Janet B.W., Rabkin, Judith, and Stern, Yaakov

Subjects
Gay men -- Physiological aspects, Bisexuality -- Health aspects, Prolactin -- Analysis, HIV infection -- Physiological aspects, Health, Psychology and mental health
Published
1992

34. Using Visual Analogies To Teach Introductory Statistical Concepts.

Author

Ancker, Jessica S. and Begg, Melissa D.

Subjects
MATHEMATICAL literacy, COGNITION, LITERATURE reviews
Abstract

Introductory statistical concepts are some of the most challenging to convey in quantitative literacy courses. Analogies supplemented by visual illustrations can be highly effective teaching tools. This literature review shows that to exploit the power of analogies, teachers must select analogies familiar to the audience, explicitly link the analog with the target concept, and avert misconceptions by explaining where the analogy fails. We provide guidance for instructors and a series of visual analogies for use in teaching medical and health statistics. [ABSTRACT FROM AUTHOR]

Published
2017
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37. Identifying and Aligning Expectations in a Mentoring Relationship

Author

Huskins, W. Charles, Huskins, W. Charles, Silet, Karin, Weber-Main, Anne Marie, Begg, Melissa D., Fowler Jr, Vance G., Hamilton, John, Fleming, Michael, Huskins, W. Charles, Huskins, W. Charles, Silet, Karin, Weber-Main, Anne Marie, Begg, Melissa D., Fowler Jr, Vance G., Hamilton, John, and Fleming, Michael

Published
2011

50. Paternal Age and Risk of Schizophrenia in Adult Offspring

Author

Brown, Alan S., primary, Schaefer, Catherine A., additional, Wyatt, Richard J., additional, Begg, Melissa D., additional, Goetz, Raymond, additional, Bresnahan, Michaeline A., additional, Harkavy-Friedman, Jill, additional, Gorman, Jack M., additional, Malaspina, Dolores, additional, and Susser, Ezra S., additional

Published
2003
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