175 research outputs found
A Conversation with Ingram Olkin
Ingram Olkin was born on July 23, 1924 in Waterbury, Connecticut. His family
moved to New York in 1934 and he graduated from DeWitt Clinton High School in
1941. He served three years in the Air Force during World War II and obtained a
B.S. in mathematics at the City College of New York in 1947. After receiving an
M.A. in mathematical statistics from Columbia in 1949, he completed his
graduate studies in the Department of Statistics at the University of North
Carolina in 1951. His dissertation was written under the direction of S. N. Roy
and Harold Hotelling. He joined the Department of Mathematics at Michigan State
University in 1951 as an Assistant Professor, subsequently being promoted to
Professor. In 1960, he took a position as Chair of the Department of Statistics
at the University of Minnesota. He moved to Stanford University in 1961 to take
a joint position as Professor of Statistics and Professor of Education; he was
also Chair of the Department of Statistics from 1973--1976. In 2007, Ingram
became Professor Emeritus. Ingram was Editor of the Annals of Mathematical
Statistics (1971--1972) and served as the first editor of the Annals of
Statistics from 1972--1974. He was a primary force in the founding of the
Journal of Educational Statistics, for which he was also Associate Editor
during 1977--1985. In 1984, he was President of the Institute of Mathematical
Statistics. Among his many professional activities, he has served as Chair of
the Committee of Presidents of Statistical Societies (COPSS), Chair of the
Committee on Applied and Theoretical Statistics of the National Research
Council, Chair of the Management Board of the American Education Research
Association, and as Trustee for the National Institute of Statistical Sciences.
He has been honored by the American Statistical Association (ASA) with a Wilks
Medal (1992) and a Founder's Award (1992). The American Psychological
Association gave him a Lifetime Contribution Award (1997) and he was elected to
the National Academy of Education in 2005. He received the COPSS Elizabeth L.
Scott Award in 1998 and delivered the R. A. Fisher Lecture in 2000. In 2003,
the City University of New York gave him a Townsend Harris Medal. An author of
5 books, an editor of 10 books, and an author of more than 200 publications,
Ingram has made major contributions to statistics and education. His research
has focused on multivariate analysis, majorization and inequalities,
distribution theory, and meta-analysis. A volume in celebration of Ingram's
65th birthday contains a brief biography and an interview [Gleser, Perlman,
Press and Sampson (1989)]. Ingram was chosen in 1997 to participate in the
American Statistical Association Distinguished Statistician Video Series and a
videotaped conversation and a lecture (Olkin, 1997) are available from the ASA
(1997, DS041, DS042).Comment: Published in at http://dx.doi.org/10.1214/088342307000000122 the
Statistical Science (http://www.imstat.org/sts/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Min and max scorings for two-sample ordinal data
Journal of the American Statistical Association, March 1992, Vol. 87, No. 417, Theory and MethodsTo analyze two-sample ordinal data, one must often assign some increasing numerical scores to the ordinal categories. The
choice of appropriate scores in these types of analyses is often problematic. This article presents a new approach for reporting
the results of such analyses. Using techniques of order-restricted inference, we obtain the minimum and maximum of standard
two-sample test statistics over all possible assignments of increasing scores. If the range of the min and max values does not
include the critical value for the test statistics, then we can immediately conclude that the result of the analysis remains the same
no matter what choice of increasing scores is used. On the other hand, if the range includes a critical value, the choice of scores
used in the analysis must be carefully justified. Numerous examples are given to clarify our approach
Mixture modeling with applications in schizophrenia research
Finite mixture modeling, together with the EM algorithm, have been widely used in clustering analysis. Under such methods, the unknown group membership is usually treated as missing data. When the "complete data" (log-)likelihood function does not have an explicit solution, the simplicity of the EM algorithm breaks down. Authors, including Rai and Matthews (1993), Lange (1995a) and Titterington (1984), developed modified algorithms therefore. As motivated by research in a large neurobiological project, we propose in this paper a new variant of such modifications and show that it is self-consistent. Moreover, simulations are conducted to demonstrate that the new variant converges faster than its predecessors. Originally published Computational Statistics and Data Analysis, Vol. 53, No. 7, May 200
Young people's experiences of managing Type 1 diabetes at university: a national study of UK university students
Aim: Little is known about the challenges of transitioning from school to university for young people with Type 1 diabetes. In a national survey, we investigated the impact of entering and attending university on diabetes selfβcare in students with Type 1 diabetes in all UK universities. Methods: Some 1865 current UK university students aged 18β24 years with Type 1 diabetes, were invited to complete a structured questionnaire. The association between demographic variables and diabetes variables was assessed using logistic regression models. Results: In total, 584 (31%) students from 64 hospitals and 37 university medical practices completed the questionnaire. Some 62% had maintained routine diabetes care with their home team, whereas 32% moved to the university provider. Since starting university, 63% reported harder diabetes management and 44% reported higher HbA1c levels than before university. At university, 52% had frequent hypoglycaemia, 9.6% reported one or more episodes of severe hypoglycaemia and 26% experienced diabetesβrelated hospital admissions. Female students and those who changed healthcare provider were approximately twice as likely to report poor glycaemic control, emergency hospital admissions and frequent hypoglycaemia. Females were more likely than males to report stress [odds ratio (OR) 4.78, 95% confidence interval (CI) 3.19β7.16], illness (OR 3.48, 95% CI 2.06β5.87) and weight management issues (OR 3.19, 95% CI 1.99β5.11) as barriers to selfβcare. Despite these difficulties, 91% of respondents never or rarely contacted university support services about their diabetes. Conclusion: The study quantifies the high level of risk experienced by students with Type 1 diabetes during the transition to university, in particular, female students and those moving to a new university healthcare provider
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Evaluation of TypeSeq, a Novel High-Throughput, Low-Cost, Next-Generation Sequencing-Based Assay for Detection of 51 Human Papillomavirus Genotypes.
BackgroundHuman papillomaviruses (HPV) cause over 500 000 cervical cancers each year, most of which occur in low-resource settings. Human papillomavirus genotyping is important to study natural history and vaccine efficacy. We evaluated TypeSeq, a novel, next-generation, sequencing-based assay that detects 51 HPV genotypes, in 2 large international epidemiologic studies.MethodsTypeSeq was evaluated in 2804 cervical specimens from the Study to Understand Cervical Cancer Endpoints and Early Determinants (SUCCEED) and in 2357 specimens from the Costa Rica Vaccine Trial (CVT). Positive agreement and risks of precancer for individual genotypes were calculated for TypeSeq in comparison to Linear Array (SUCCEED). In CVT, positive agreement and vaccine efficacy were calculated for TypeSeq and SPF10-LiPA.ResultsWe observed high overall and positive agreement for most genotypes between TypeSeq and Linear Array in SUCCEED and SPF10-LiPA in CVT. There was no significant difference in risk of precancer between TypeSeq and Linear Array in SUCCEED or in estimates of vaccine efficacy between TypeSeq and SPF10-LiPA in CVT.ConclusionsThe agreement of TypeSeq with Linear Array and SPF10-LiPA, 2 well established standards for HPV genotyping, demonstrates its high accuracy. TypeSeq provides high-throughput, affordable HPV genotyping for world-wide studies of cervical precancer risk and of HPV vaccine efficacy
A Pilot Study of IL-2RΞ± Blockade during Lymphopenia Depletes Regulatory T-cells and Correlates with Enhanced Immunity in Patients with Glioblastoma
Preclinical studies in mice have demonstrated that the prophylactic depletion of immunosuppressive regulatory T-cells (T(Regs)) through targeting the high affinity interleukin-2 (IL-2) receptor (IL-2RΞ±/CD25) can enhance anti-tumor immunotherapy. However, therapeutic approaches are complicated by the inadvertent inhibition of IL-2RΞ± expressing anti-tumor effector T-cells.To determine if changes in the cytokine milieu during lymphopenia may engender differential signaling requirements that would enable unarmed anti-IL-2RΞ± monoclonal antibody (MAbs) to selectively deplete T(Regs) while permitting vaccine-stimulated immune responses.A randomized placebo-controlled pilot study was undertaken to examine the ability of the anti-IL-2RΞ± MAb daclizumab, given at the time of epidermal growth factor receptor variant III (EGFRvIII) targeted peptide vaccination, to safely and selectively deplete T(Regs) in patients with glioblastoma (GBM) treated with lymphodepleting temozolomide (TMZ).Daclizumab treatment (n = 3) was well-tolerated with no symptoms of autoimmune toxicity and resulted in a significant reduction in the frequency of circulating CD4+Foxp3+ TRegs in comparison to saline controls (n = 3)( p = 0.0464). A significant (p<0.0001) inverse correlation between the frequency of TRegs and the level of EGFRvIII specific humoral responses suggests the depletion of TRegs may be linked to increased vaccine-stimulated humoral immunity. These data suggest this approach deserves further study.ClinicalTrials.gov NCT00626015
Evidence for single-dose protection by the bivalent HPV vaccine-Review of the Costa Rica HPV vaccine trial and future research studies.
The Costa Rica Vaccine Trial (CVT), a phase III randomized clinical trial, provided the initial data that one dose of the HPV vaccine could provide durable protection against HPV infection. Although the study design was to administer all participants three doses of HPV or control vaccine, 20% of women did not receive the three-dose regimens, mostly due to involuntary reasons unrelated to vaccination. In 2011, we reported that a single dose of the bivalent HPV vaccine could be as efficacious as three doses of the vaccine using the endpoint of persistent HPV infection accumulated over the first four years of the trial; findings independently confirmed in the GSK-sponsored PATRICIA trial. Antibody levels after one dose, although lower than levels elicited by three doses, were 9-times higher than levels elicited by natural infection. Importantly, levels remained essentially constant over at least seven years, suggesting that the observed protection provided by a single dose might be durable. Much work has been done to assure these non-randomized findings are valid. Yet, the group of recipients who received one dose of the bivalent HPV vaccine in the CVT and PATRICIA trials was small and not randomly selected nor blinded to the number of doses received. The next phase of research is to conduct a formal randomized, controlled trial to evaluate the protection afforded by a single dose of HPV vaccine. Complementary studies are in progress to bridge our findings to other populations, and to further document the long-term durability of antibody response following a single dose
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