79 research outputs found
Rearranging Edgeworth-Cornish-Fisher Expansions
This paper applies a regularization procedure called increasing rearrangement
to monotonize Edgeworth and Cornish-Fisher expansions and any other related
approximations of distribution and quantile functions of sample statistics.
Besides satisfying the logical monotonicity, required of distribution and
quantile functions, the procedure often delivers strikingly better
approximations to the distribution and quantile functions of the sample mean
than the original Edgeworth-Cornish-Fisher expansions.Comment: 17 pages, 3 figure
Cost calculation and prediction in adult intensive care: A ground-up utilization study
Publisher's copy made available with the permission of the publisherThe ability of various proxy cost measures, including therapeutic activity scores (TISS and Omega) and cumulative daily severity of illness scores, to predict individual ICU patient costs was assessed in a prospective “ground-up” utilization costing study over a six month period in 1991. Daily activity (TISS and Omega scores) and utilization in consecutive admissions to three adult university associated ICUs was recorded by dedicated data collectors. Cost prediction used linear regression with determination (80%) and validation (20%) data sets. The cohort, 1333 patients, had a mean (SD) age 57.5 (19.4) years, (41% female) and admission APACHE III score of 58 (27). ICU length of stay and mortality were 3.9 (6.1) days and 17.6% respectively. Mean total TISS and Omega scores were 117 (157) and 72 (113) respectively. Mean patient costs per ICU episode (1991 6801 (2534, range 95,602. Dominant cost fractions were nursing 43.3% and overheads 16.9%. Inflation adjusted year 2002 (mean) costs were AUS). Total costs in survivors were predicted by Omega score, summed APACHE III score and ICU length of stay; determination R2, 0.91; validation 0.88. Omega was the preferred activity score. Without the Omega score, predictors were age, summed APACHE III score and ICU length of stay; determination R2, 0.73; validation 0.73. In non-survivors, predictors were age and ICU length of stay (plus interaction), and Omega score (determination R2, 0.97; validation 0.91). Patient costs may be predicted by a combination of ICU activity indices and severity scores.J. L. Moran, A. R. Peisach, P. J. Solomon, J. Martinhttp://www.aaic.net.au/Article.asp?D=200403
Azimuthal anisotropy of K0s and Lambda prduction at mid-rapidity from Au+Au collisions at root s = 130 GeV
We report STAR results on the azimuthal anisotropy parameter v2 for strange
particles K0S, L and Lbar at midrapidity in Au+Au collisions at sNN = 130 GeV
at RHIC. The value of v2 as a function of transverse momentum of the produced
particles pt and collision centrality is presented for both particles up to pt
3.0 GeV/c. A strong pt dependence in v2 is observed up to 2.0 GeV/c. The v2
measurement is compared with hydrodynamic model calculations. The physics
implications of the pt integrated v2 magnitude as a function of particle mass
are also discussed.Comment: 6 pages, 4 figures, by the STAR collaboratio
Predicting oral anticoagulant response using a pharmacodynamic model
We developed a pharmacokinetic and pharmacodynamic model of warfarin absorption, metabolism, and anticoagulant action appropriate for guiding anticoagulant therapy. The model requires only two independently adjustable parameters to describe warfarin's effect on individual patients. For any given individual, these parameters are rapidly and inexpensively identified using a computer program based on the model. Test data were generated by superimposing Gaussian noise on dose-response curves calculated with the model. Then the computer program was applied to the test data. Future prothrombin complex activities (PCA's) and maintenance doses were predicted accurately early in the course of drug administration. In addition, the program accurately predicted PCA response in two groups of normal volunteers.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44006/1/10439_2006_Article_BF02363455.pd
Production in Relativistic Heavy Ion Collisions at GeV
We report the first observation of in
relativistic heavy ion collisions. The transverse momentum spectrum of
from central Au+Au collisions at
GeV is presented. The ratios of the yield
derived from these data to the yields of negative hadrons, charged kaons, and
mesons have been measured in central and minimum bias collisions and
compared with model predictions and comparable , , and
results. The data indicate no dramatic reduction of
production in relativistic heavy ion collisions despite expected losses due to
rescattering effects.Comment: 6 pages, 3 figures, To be published in PRC
Body Mass Index, Physical Activity, Sedentary Behavior, Sleep, and Gross Motor Skill Proficiency in Preschool Children From a Low- to Middle-Income Urban Setting
BACKGROUND: Limited research reports on the relationship between body mass index (BMI) and physical activity (PA), sedentary behavior (SB), sleep, and gross motor skills (GMS) in low- and middle-income countries. The aim of this study was to (1) describe BMI, PA, SB, sleep duration, and GMS proficiency in South African preschool children and (2) identify relationships between variables. METHODS: BMI, including z scores for height, weight, and BMI were determined. Seven-day PA, SB, and sleep were measured using accelerometry. GMS were assessed using the Test of Gross Motor Development (second edition). Associations were explored by comparing sleep, PA, SB, and GMS between BMI tertiles using the Kruskal-Wallis test. RESULTS: Most (86%) children (n = 78, 50% boys) had a healthy BMI (15.7 [1.3] kg/m2). Children spent 560.5 (52.9) minutes per day in light- to vigorous-intensity PA and 90.9 (30.0) minutes per day in moderate- to vigorous-intensity PA; most (83%) met the current PA guideline. Nocturnal sleep duration was low (9.28 [0.80] h/d). Although daytime naps increased 24-hour sleep duration (10.17 [0.71] h/d), 38% were classified as short sleepers. Around half (54.9%) of participants complied with both PA and sleep guidelines. No associations between variables were found. CONCLUSION: Despite being lean, sufficiently active, and having adequate GMS, many children were short sleepers, highlighting a possible area for intervention
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