Papers by Katherine Halvorsen
This comprehensive account of statistics education in the USA describes the changes in the Americ... more This comprehensive account of statistics education in the USA describes the changes in the American Statistical Association's (ASA) statistics education efforts during the past 30 years. These changes include the creation of committees that support the work of statistics educators in mathematics departments in four-year colleges and universities, in two-year colleges, and in schools, along with ASA recommendations on course requirements for undergraduate statistics majors and guidelines for assessment and instruction in statistics education in kindergarten through secondary school and in the first-year of college (the GAISE reports). The paper concludes with continuing and new challenges, along with future opportunities, for statistics educators in the United States and other countries.
Journal of Business Finance & Accounting, 1993
Medical Uses of Statistics, 2019
22 COMBINING RESULTS FROM INDEPENDENT INVESTIGATIONS META-ANALYSIS IN CLINICAL RESEARCH Katherine... more 22 COMBINING RESULTS FROM INDEPENDENT INVESTIGATIONS META-ANALYSIS IN CLINICAL RESEARCH Katherine Taylor Halvorsen, D. Sc., Elisabeth Burdick, MS, Graham A. Colditz, MD, DPH, Howard S. Frazier, MD, and Frederick Mosteller, Ph. D. ABSTRACT ...
American Journal of Epidemiology, 1989
Long term recalls of dietary intake are frequently used in case-control studies, but their validi... more Long term recalls of dietary intake are frequently used in case-control studies, but their validity and reliability have not been established. In this study, 91 middle-aged adults (median age, 50 years) who were participants in the Longitudinal Study of Child Health and Development at the Harvard School of Public Health in Boston, Massachusetts, starting in the early 1930s, were asked in 1984-1985 to report present food intake and to recall food intakes at ages 5-7 years. 18 years, and 30 years using food frequency questionnaires. Their recalled intakes were validated by comparison with historical records of intake collected during the earlier time periods. Recall of food intake in the distant past was a better predictor of historical intake than was current diet. However, correlations between recalled and historical consumption for individual foods and food groups were generally low, rarely exceeding 0.3. Current intakes exerted a powerful influence on accuracy of recall. The consideration of participant characteristics did not prove to be consistently useful in explaining variations in food item and food group-related recall. The authors conclude that recall of food intake in the distant past may be a sufficiently valid estimate of past intake to justify its collection.
Amstat News the Membership Magazine of the American Statistical Association, 2010
Amstat News the Membership Magazine of the American Statistical Association, 2013
Amstat News the Membership Magazine of the American Statistical Association, 2014
Los encargados de la enseñanza de las matemáticas desde preescolar hasta undécimo año, tienen una... more Los encargados de la enseñanza de las matemáticas desde preescolar hasta undécimo año, tienen una tarea muy importante e influyente en el desarrollo de la sociedad. Son los docentes quienes deben formar a los estudiantes en esta área. Sin embargo, algunos de los docentes encargados de la formación, en matemáticas, no tienen la preparación adecuada para hacerlo, principalmente, los docentes de los niveles más básicos como desde preescolar hasta primaria. Conscientes de la necesidad de formación y capacitación de docentes en servicio, y en formación, es que algunas organizaciones de los Estados Unidos han trabajado tanto en diagnosticar la magnitud del problema como de plantear posibles soluciones al mismo dentro de su nación. Palabras clave Educación matemática, formación docente, sistema educativo.
Metallomics, 2013
Vanadium, abbreviated V, is an early transition metal that readily forms coordination complexes w... more Vanadium, abbreviated V, is an early transition metal that readily forms coordination complexes with a variety of biological products such as proteins, metabolites, membranes and other structures. The formation of coordination complexes stabilizes metal ions, which in turn impacts the biodistribution of the metal. To understand the biodistribution of V, V in oxidation state IV in the form of vanadyl sulfate (25, 50, 100 mg V daily) was given orally for 6 weeks to 16 persons with type 2 diabetes. Elemental V was determined using Graphite Furnas Atomic Absorption Spectrometry against known concentrations of V in serum, blood or urine. Peak serum V levels were 15.4±6.5, 81.7±40 and 319±268 ng/ml respectively, and mean peak serum V was positively correlated with dose administered (r=0.992, p=0.079), although large inter-individual variability was found. Total serum V concentration distribution fit a one compartment open model with a first order rate constant for excretion with mean half times of 4.7±1.6 days and 4.6±2.5 days for the 50 and 100 mg V dose groups respectively. At steady state, 24 hour urinary V output was 0.18±0.24 and 0.97±0.84 mg in the 50 and 100 mg V groups respectively, consistent with absorption of 1 percent or less of the administered dose. Peak V in blood and serum were positively correlated (r=0.971, p<0.0005). The serum to blood V ratio for the patients receiving 100 mg V was 1.7±0.45. Regression analysis showed that glycohemoglobin was a negative predictor of the natural log (ln) peak serum V (R 2 =0.40, p=0.009) and a positive predictor of the euglycemic hyperinsulinemic clamp results at high insulin values (R 2 =0.39, p=0.010). Insulin sensitivity measured by euglycemic hyperinsulinemic clamp was not significantly correlated with ln peak serum V. Globulin and glycohemoglobin levels taken together were negative predictors of fasting blood glucose (R 2 =0.49, p=0.013). Although V accumulation in serum was dose-dependent, no correlation between total serum V concentation and the insulin-like response was found in this first attempt to correlate anti-diabetic activity with total serum V. This study suggests that V pools other than total serum V are likely related to the insulin-like effect of this metal. These results,
Journal of the American Statistical Association, 1981
In general, the algorithm does not require the total enu-meration of all tables consistent with t... more In general, the algorithm does not require the total enu-meration of all tables consistent with the given marginals. As a result, it is faster than existing algorithms. ... Given the integral, rxc matrix X whose coefficients are count data for a two-way classification scheme, the ...
Journal of Experimental Medicine, 1998
The thymus plays a critical role in the maturation and production of T lymphocytes and is a targe... more The thymus plays a critical role in the maturation and production of T lymphocytes and is a target of infection by human immunodeficiency virus (HIV) and the related simian immunodeficiency virus (SIV). Using the SIV/macaque model of AIDS, we examined the early effects of SIV on the thymus. We found that thymic infection by SIV resulted in increased apoptosis 7–14 d after infection, followed by depletion of thymocyte progenitors by day 21. A marked rebound in thymocyte progenitors occurred by day 50 and was accompanied by increased levels of cell proliferation in the thymus. Our results demonstrate a marked increase in thymic progenitor activity very early in the course of SIV infection, long before marked declines in peripheral CD4+ T cell counts.
BMC Biology, 2012
Background The Deepwater Horizon disaster was the largest marine oil spill in history, and total ... more Background The Deepwater Horizon disaster was the largest marine oil spill in history, and total vertical exposure of oil to the water column suggests it could impact an enormous diversity of ecosystems. The most vulnerable organisms are those encountering these pollutants during their early life stages. Water-soluble components of crude oil and specific polycyclic aromatic hydrocarbons have been shown to cause defects in cardiovascular and craniofacial development in a variety of teleost species, but the developmental origins of these defects have yet to be determined. We have adopted zebrafish, Danio rerio, as a model to test whether water accumulated fractions (WAF) of the Deepwater Horizon oil could impact specific embryonic developmental processes. While not a native species to the Gulf waters, the developmental biology of zebrafish has been well characterized and makes it a powerful model system to reveal the cellular and molecular mechanisms behind Macondo crude toxicity. Res...
Applied Animal Behaviour Science, 2007
In female canids, including domestic dogs (Canis familiaris), scent-marking with urine is thought... more In female canids, including domestic dogs (Canis familiaris), scent-marking with urine is thought to convey information on reproductive state, yet little is known about how urinary behaviour changes across specific stages of the oestrous cycle. We measured urinary behaviour (proportion of directed urinations) of 10 intact Jack Russell Terriers across anoestrus, proestrus, and oestrus during walks in familiar and novel environments. Females ranged in age from 1.3 to 8.7 years. We assessed stage of oestrus using vaginal cytology, behaviour, and physical signs. Proportions of directed urinations were higher during proestrus and oestrus than anoestrus, and were higher in older females than younger females. Our findings indicate that in female Jack Russell Terriers, scent-marking with urine advertises reproductive state and continues to develop in adulthood. Additional data are needed to determine if these findings generalize to female dogs of other breeds and mixed breeds.
American Heart Journal, 1988
In C. Reading (Ed.), Data and context in statistics education: Towards an evidence-based society.... more In C. Reading (Ed.), Data and context in statistics education: Towards an evidence-based society. Proceedings of the Eighth International Conference on Teaching Statistics (ICOTS8, July, 2010), Ljubljana, Slovenia. Voorburg, The Netherlands: International Statistical Institute. www.stat.auckland.ac.nz/~iase/publications.php [© 2010 ISI/IASE] FORMULATING STATISTICAL QUESTIONS AND IMPLEMENTING STATISTICS PROJECTS IN AN INTRODUCTORY APPLIED STATISTICS COURSE
Uploads
Papers by Katherine Halvorsen