Physical Sciences and Mathematics Commons^™

Topologies Invariant Under A Group Action, Paul Bankston

Mathematics, Statistics and Computer Science Faculty Research and Publications

We study links between faithful group actions on a set and topologies on that set. In one direction, a group action has its invariant topologies (so we may regard members of the action to be homeomorphisms relative to those topologies); in the other direction, a topology has its preserving group actions (i.e., the subgroups of the homeomorphism group of the topology). This two-way passage allows us to discuss topological features of group actions as well as symmetry features of topologies.

Aids Epidemiology: A Quantitative Approach, Ron Brookmeyer, Mitchell Gail

Ron Brookmeyer

This comprehensive work confronts the problems that are unique to AIDS research and unites them under a single conceptual framework. It focuses on methods for the design and analysis of epidemiologic studies, the natural history of AIDS and the transmission of HIV, methods for tracking and projecting the course of the epidemic, and statistical issues in therapeutic trials. The various methods of monitoring and forecasting this disease receive comprehensive treatment. These methods include back-calculation, which the authors developed; interpretation of survey data on HIV prevalence; mathematical models for HIV transmission; and approaches that combine different types of epidemiological data. Much …

Student Fact Book, Fall 1994, Wright State University, Office Of Student Information Systems, Wright State University

Wright State University Student Fact Books

The student fact book has general demographic information on all students enrolled at Wright State University for Fall Quarter, 1994.

Application Of The Binomial Index Of Model Fit: What Research Question Is Being Investigated?, Isadore Newman, John Fraas, Timothy Norfolk

John W. Fraas

No abstract provided.

The Relationship Of Dietary And Lifestyle Factors To Bone Mineral Density Of Healthy Singaporean Chinese Women, Ampai Dana Aimsiri

Loma Linda University Electronic Theses, Dissertations & Projects

Few studies have examined the risk factors associated with reduced bone mass in Asians, but none specifically investigated Singaporean Chinese women. The subjects in this study were 16 premenopausal, 8 perimenopausal and 13 postmenopausal women who participated in a larger study which began in 1986. Bone density was measured in 1986 and 1992. Dietary and lifestyle data were collected for this study by personal interview. Association between dietary and lifestyle factors and bone density variables and change in bone density at the end of the 6 year period were assessed by univariate regression analyses.

Postmenopausal women had significantly lower baseline …

An Integrated Infrastructure Management System, William V. Harper, Kamran Majidzadeh

Mathematics Faculty Scholarship

This paper describes an integrated infrastructure system (with emphasis on pavement and bridge management systems) that allows cost minimization or benefit maximization. It integrates separate infrastructure systems so that management may optimally allocate scarce resources across the combined systems. Fuzzy set theory is used in these optimizations to better address the desirability or undesirability of the condition states used to categorize the infrastructure segments modeled. Both steady-state and multi-year models are part of this system. The full mathematical structure of the simpler steady-state problem is presented, and sample multi-year output showing the integrated budgets is given.

Evolving Plane Curves By Curvature In Relative Geometries Ii, Michael E. Gage, Yi Li

Mathematics and Statistics Faculty Publications

In this paper we prove the existence of self-similar solutions to the anisotropic curve shortening equation.

Some Sampling Designs And Estimation Problems, Hassan Lakkis

Mathematics & Statistics Theses & Dissertations

In the first chapter we review some standard estimators in sampling from a finite population, and some design-based estimators in sampling from a continuous universe.

In concert with the theory initiated by professor Douglas Robson (personal communication) and later presented by Cordy (1993), we consider design-based variance estimation for probability sampling from a continuous and spatially distributed universe. Using this theory in chapter two, the sampling design of one random point from each cell of a translated grid is investigated and the problem of edge effects on estimation is illustrated with examples. Also in chapter four, standard systematic sampling methods …

Remarks On Automorphisms Of Subfactors, Phan Loi

Mathematics and Statistics Faculty Publications

We establish certain properties of automorphisms on an inclusion of AFD type II₁ factors with finite index and finite depth and discuss their applications to the classification problem of AFD type III subfactors, including a different proof of a result on subfactors with principal graph D_n.

The Media, Risk Assessment And Numbers: They Don't Add Up, Sharon M. Friedman

RISK: Health, Safety & Environment (1990-2002)

Professor Friedman argues that, for risks to be reported accurately, journalism educators must help their students understand science, numbers and statistics.

Militarywide Survey Of Whole-Grain Food Products And Total Dietary Fiber Analysis Of The Military Ration, John Paul Warber

Loma Linda University Electronic Theses, Dissertations & Projects

Numerous scientific bodies have made the recommendation to increase consumption of whole-grain breads and cereals. This study used a telephone survey to assess the availability of whole-grain foods in a random selection of 109 military installations and 30 military hospitals. Surveyed installations represent over 70% of the active duty military population assigned in the continental United States.

Military food service specialists were asked questions regarding the availability of the following whole-grain products: bread, rolls, buns, flour, pancake mix, brown rice, and ready-to-eat cereals (RTE). They were then asked to read the product ingredient list to validate their perceptions. Perceived availability …

Measurement Of Blood Flow In Reflected Muco-Gingival Tissue Flaps In Cats : Using The Radiolabeled Microsphere Method, Gary T. Wuchenrich

Loma Linda University Electronic Theses, Dissertations & Projects

Blood flow to the maxilla and mandible may vary due to differences in vascular supply and in physiologic, metabolic and pathologic conditions. In general it is accepted that oral tissues have an abundant blood supply; however, there is little information quantifying blood flow to these regions. In this study, the maxillary tissues were chosen to measure the blood flow in attached and reflected gingival tissue in adult cats using the radiolabeled microsphere method.

Sixteen cats with permanent dentition, clean mouths, and without inflamed gingiva upon visual inspection were used and divided into two groups. Group 1 consisted of six cats …

Long-Term Posttreatment Upper Incisor Inclination : Relative To Facial Axis Angulation As A Measure For Incisor Placement, David Lawrence Sparks

Loma Linda University Electronic Theses, Dissertations & Projects

This study was designed to determine whether upper central incisor inclination approximated the facial axis, long-term, posttreatment, regardless of the initial malocclusion or immediate posttreatment incisor inclination. Lateral head films at pretreatment, immediate posttreatment and long-term posttreatment were traced and evaluated. The sample was divided into facial type. Angle classification and treatment type (extraction vs. non-extraction). Statistical analyses included means, standard deviations, confidence intervals, population t tests and chi-square tabulations.

The results revealed that the upper central incisor did not approximate the facial axis after a minimum of 7 years posttreatment. This failed to support the use of the facial …

Identification Of Risk Factors Associated With Pulpal Disease, Shelley R. Aronson

Loma Linda University Electronic Theses, Dissertations & Projects

A few studies have identified etiologic factors in pulpal disease, but little is known about the odds ratios of factors associated with pulpal disease. Odds ratios are well established measures of the effects of exposure to a particular outcome, and are comparisons of exposure to non-exposure in cases versus controls. The purpose of this study was to compare exposure of individual teeth to hypothesized risk factors in endodontic cases and in controls. This case-control study consisted of a chart review of 301 endodontic cases and 301 controls. Caries, types of restorations, and periodontal disease were the most significant factors. With …

Statistical Properties And Problems In Modeling The Bolivian Foreign Exchange Market, Gover Barja

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Bolivian foreign exchange market is explained in terms of the official and parallel exchange rates. The data covers the post hyper inflationary period from 1986 to 1992. The distribution of the rate of depreciation of the official and parallel exchange rates is long tailed and strongly departs from normality due to the existence of outliers. A market interactions model of the autoregressive kind is estimated using robust regression. This procedure produces M-parameter estimates using iteratively reweighted least squares. The robust method handles well the outlier problem and at the same time it reveals the true nature of the statistical …

An Empirical Study Of Small-Area Variation For Icd-9 Surgical Procedures, Paula Diehr, Kevin Cain, Zhan Ye, John Loeser

UW Biostatistics Working Paper Series

Objective. Several measures of variation have been used in SAVA. One study of DRGs found that the coefficient of variation from analysis of variance (CVA) had superior performance. That work is replicated here for ICD-9 surgical procedures, and extended to age/sex-standardized rates. Results are compared with those in the literature, and recommendations are made for assessing small-area variation in future studies.

Data Sources. Data were taken from Washington State's "Episode of Illness" file of hospital discharges in the State in 1987. Up to three ICD-9 surgical procedures and a unique patient identifier were available for each discharge.

Study Design. We …

Prediction Of Breeding Values For Unmeasured Traits From Measured Traits, Kristin L. Barkhouse, L. Dale Van Vleck

Conference on Applied Statistics in Agriculture

Henderson (1977, 1984) described a method for prediction of breeding values for traits not in the model for records. This method may be practical for animal or sire models for the case when no measurements can be obtained on any animals for some traits to be evaluated. The least squares equations are augmented with A^-1⊗G_N^-1 rather than with A^-1⊗G₀^-1 where A is the numerator relationship and G₀and G_N are the genetic covariance matrices for measured and for all traits. This method can be used for each unmeasured trait or …

Applications Of Estimable Functions In Agricultural Research With Special Emphasis On The Glm Procedure Of Sas., L. Munyakazi, R. L. Hintz, B. D. Selby

Conference on Applied Statistics in Agriculture

An understanding of estimable functions is essential when using an overparameterized linear model. The most attractive features of these functions are their invariance property to the solution vector and their wide range of practical applications in agricultural research. This study reviews some of the ways that estimable functions can be used by the agricultural scientist.

Extrapolating Intra-Cluster Correlation To Optimize The Size Of Segments In An Area Frame., E. Carfagna, F. J. Gallego

Conference on Applied Statistics in Agriculture

In the frame of the "Rapid Crop Area Estimates in the European Community" we use a sample of squared segments (pieces of land) of 49 ha. each; estimates are made for difference of crop areas between years. The optimum size seems to be larger than the current one, and much larger if ground survey data are obtained by photo-interpretation. The main purpose of this paper is to assess a method, based on splitting the segments into pieces of 1/4 ha., to forecast the precision of estimates with larger segments. The tests made for France confirm the belief that better estimates …

Modelling Within-Plant Spatial Dependencies Of Cotton Yield, E. B. Moser, R. E. Macchiavelli, D. J. Boquet

Conference on Applied Statistics in Agriculture

In field experiments during 1987-1990, cotton plants were grown under 8 different levels of nitrogen application to assess the impact of nitrogen fertilization on the fruiting and yield distribution of cotton within the plant (Boquet et al. 1993).lr.dividual boll weights and average seedcotton yield were determined at each fruiting site fur each main-stem node along the plant. Various models of dependence and independence are possible to explain and account for the dependencies of the yields among the sites and nodes of the plant. Here we investigate models of total yield per node and yield per node adjusted for the number …

Fitting Bole-Volume Equations To Spatially Correlated Within-Tree Data, Timothy G. Gregoire, Oliver Schabenberger

Conference on Applied Statistics in Agriculture

Equations to predict the volume of an individual tree bole between stump height and the height at which its diameter has tapered to a specified minimum are common in forestry. When fitting such a regression equation, a sample of trees which span the range of sizes needed for eventual application of the equation is selected. Bole diameter is measured at ascending heights on the bole. Each tree, therefore, contributes multiple measurements to the data fitted to the equation. In contrast to past practice, we model these data in a manner which accounts for the likely spatial correlation among measurements within …

A Bootstrap Analysis Of Temperature Effects On Bean Leaf Beetle Egg Hatch Times, Kenneth J. Koehler

Conference on Applied Statistics in Agriculture

The bean leaf beetle (Cerotoma trifurcata) is a significant soybean pest in the Midwest. The possibility of reducing crop damage by disrupting the synchrony between emergence of F2 adults and the availability of young green pods requires an increased understanding of bean leaf beetle (BLB) phenology. An important consideration in predicting emergence of F2 adults is the influence of temperature on the rates of egg and larval development. In this article we concentrate on the analysis of data from a controlled study of the effects of temperature on both the hatch time distribution and the viability of BLB …

Nonlinear Regression Functions For Forage Nutrient Disappearance From Bags Incubated In The Rumen, W. J. E. Potts, B. P. Glenn, J. B. Reeves, R. A. Erdman

Conference on Applied Statistics in Agriculture

Seven nonlinear regression functions are compared for fitting rumen in situ disappearance data. The standard function is based on a simple one-compartment model. In addition, we consider a time lag modification, a two-compartment model, and functions based on underlying probability models for degradation time. The empirical suitability of the seven regression functions are assessed using two in situ experiments involving forages fed to dairy cows. A function based on the loglogistic distribution is shown to have empirical and theoretical advantages.

Obtaining Models For Alfalfa, Sorghum, And Wheat Residue Decomposition, H. H. Schomberg, T. W. Popham

Conference on Applied Statistics in Agriculture

Crop residues provide an economical means for controlling wind and water erosion in addition to being a valuable source of plant nutrients. As residues decompose they lose nutrients, mass and the ability to protect the soil surface from erosive forces. The research was designed to evaluate rates of residue decomposition of sorghum, wheat and alfalfa on the soil surface and buried, in five soil moisture regimes. Moisture was applied to soil by line source irrigation and bags containing crop residues were retrieved and analyzed across time. Thus, observations were repeated in both space and time .

Wieder and Lang (1982) …

Determination Of The Inoculation Frequency, Timing Of Inoculation And Dose Of A Bacterial Ruminal Inoculant For Acidosis Prevention In Feedlot Cattle, J. F. Boucher, W. J. Smolenski, J. A. Robinson

Conference on Applied Statistics in Agriculture

We are evaluating the efficacy of a ruminal bacterial inoculant (Megasphaera elsdenii 407 A) for prevention of acute acidosis in grain-fed cattle. As a part of this process, we examined the effects of inoculation frequency, timing of inoculation and dose of 407 A for prevention of acute acidosis in ruminally fistulated cattle. Three levels of frequency, two levels of timing and three doses were considered, however, a complete 3x2x3 factorial study was not run because of resource constraints. The study was conducted in two separate trials. The first was designed as a 3x2 factorial experiment with inoculation frequency and timing …

Design For The Experimenter, O. B. Allen, D. A.J. Ryan

Conference on Applied Statistics in Agriculture

Three research problems, for which there was no obvious textbook design available, are presented. Each of the three involve constructing incomplete block designs for factorial treatment arrangements. While the designs are not likely optimal by any of the classical criteria, they meet the objectives of the research projects. The constructions involved confounding, with incomplete blocks, those effects which were of least interest. However, effects of interest were also allowed to be slightly non-orthogonal to blocks in order to be able to examine a larger number of effects of interest.

Experimental Error In Agronomic Field Trials, Thomas M. Loughin, D. F. Cox, Paul N. Hinz, William T. Schapaugh Jr., Lora Kilgore-Norquest

Conference on Applied Statistics in Agriculture

Agronomic experiments often summarize work carried out in trials run in several locations over several years, referred to generically as environments. The appropriate statistical analyses for these experiments depend on definitions used for experimental error. The results of one such experiment, in which identical designs were used in each environment, illustrate the commonalities and differences in analyses that can result from using different definitions of experimental error.

Markov-Recapture Population Estimates, E. Paul Wileyto

Conference on Applied Statistics in Agriculture

This paper reviews recent development of a method for estimating insect populations. It is like mark-recapture methods, except that marking is done passively at bait stations by the insects themselves, and capture probabilities are generated using a simple Markov process model. Assumptions about rates of marking and capture are made from the sampling scheme, and the estimate is based upon the resulting multinomial probability distribution and maximum likelihood methods. The paper continues to review the sampling distributions for the population estimate, revealed by simulation, and explores correction of the bias. Relative likelihood based confidence intervals are compared with two standard …

Predicting Common Crupina Habitat With Geographic And Remote Sensing Data, Timothy S. Prather, Bahman Shafii, Robert H. Callihan

Conference on Applied Statistics in Agriculture

Field surveys for common crupina, as part of an eradication program, are time intensive and could be made more efficient if common crupina habitat could be predicted. Slope, aspect, and vegetation data were used as generalized plant community variables to predict common crupina habitat using a transformed logistic regression. Models were constructed using either aspect or slope as an explanatory variable such that one model predicted the overall effect of either slope or aspect and a set of models predicted the effect of slope or aspect at each of three vegetation classes. A second data set was used to validate …

Stratification And Cluster Estimator On An Area Frame By Squared Segments With An Aligned Sample, M. Fuentes, F J. Gallego

Conference on Applied Statistics in Agriculture

Several European countries (Portugal, Spain, Greece, Rumania, and the Czech Republic) make crop surveys on area frame with an aligned systematic sampling of squared segments. So far crop area estimates are obtained with standard formulae for random sampling, without using the spatial structure of the sample. This is in general conservative, the estimated standard error is larger than the error actually made. Taking as clusters the set of segments with the same relative position in a block, gives often lower but very unstable variances. A more stable variance estimate is computed by repeated random permutations of the sample segments in …