Center for Statistical Research in the Environmental, Earth, and Life Sciences
The Center is a focal point for the research interests and accomplishments of several faculty members in the Department of Statistical Science. Most of these projects involve collaborations, both off-campus and on-campus, that are important to progress in the medical, environmental, and earth sciences. This research center fosters joint investigations of a rich variety of developments of new methodologies for data analysis in these particular areas of scientific research. Selected co-investigators and colloquium speakers enhance the intellectual pursuits of both faculty and graduate students with these interests.
Projects that are ideal for the Center draw upon a common set of statistical research specialties, which include
Some recent professional activities of Professors Gray, Gunst, Harris, McGee, Schucany and Woodward are described here. The list conveys the breadth of our commitment to these thriving branches of research within the discipline of statistical science.
| Functional Magnetic Resonance Imaging (fMRI) of Cognitive Functioning, UTSWMC. Functional MRI of cognitive functioning is utilized increasingly for the study of neurological disorders, including the evaluation of the response to treatment. More needs to be known about the reproducibility of fMRI findings for many cognitive tasks. A research team addressed this in a pilot study of five healthy volunteers.SMU statisticians worked with researchers at the University of Texas Southwestern Medical Center (UTSWMC) on statistical inference for fMRI data, with applications in the treatment of stroke patients. |
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Dick Gunst, Wayne Woodward, and Bill Schucany are collaborating with medical imaging colleagues at the UTSWMC on a new initiative in functional magnetic resonance imaging (fMRI). The main initial thrust of the initiative is statistical modeling of SPECT data that were taken on veterans of the Persian Gulf War who are suffering from what is now being called the Gulf War Syndrome. Dr. Robert Haley and colleagues at UTSWMC have characterized the Gulf War Syndrome using factor analyses of data collected from questionnaires administered to the veterans. Subsequent work has led the researchers to believe that fMRI might refine the understanding of the areas of the brain that have been affected. Current analyses of brain imaging data do not comprehensively incorporate spatial and temporal variation in the measurements, two focal points of the research by the Gunst, Schucany, Woodward and graduate student research assistants from the Department of Statistical Science.
Improving Learning of Technical Material by the Disabled. Buddy Gray has developed some software to help the handicapped learn statistics. His voice-activated technical word processor allowed a quadriplegic SMU undergraduate to successfully handle all of the material in our sophomore service course. This computer program also was essential to a blind master’s student completing his degree program that included a substantial amount of equations. Both NSF and NIH are considering how this package might be an essential assistance to people of all ages with disabilities.
New Methodology for Medical Data . How should one scatterplot data on twins? Mike Ernst, Rudy Guerra, and Bill Schucany answered this very basic question satisfactorily in a 1996 article in The American Statistician. A test of the broader class of bivariate interchangeability (which includes identical twins) was published in 1999 in the Journal of the American Statistical Association by Ernst and Schucany. Their results apply to medical baseline test/retest situations. Ian Harris has published a paper in Journal of Agricultural, Biological and Environmental Sciences in collaboration with Brent Burch and Roy St. Laurent of Northern Arizona University on the topic of measurement comparison. They investigate a type of correlation coefficient that is suitable for comparison of an approximate measurement with a more exact "gold standard" measurement. The method is applied to data on infarctions in canines.
Improved Diagnostic Tool for Heart Disease . Buddy Gray and Wayne Woodward are using signal-processing techniques in a fundamentally new research project using sonograms to classify patients with heart disease. This development promises to be a dramatic departure with greater accuracy than the present approach with electrocardiograms.
Other Biostatistical Projects . With researchers at the Parkinson’s Disease Association of Dallas, at Presbyterian Hospital Bill Schucany is beginning a new analytical approach to early diagnosis of this neurological disorder. Basic research at Baylor Research Institute on immunology and liver cancer require the analysis of microarray data. Bill Schucany and Sherry Wang are beginning to discuss this topic with medical scientists at Baylor. Similar collaborations are also beginning on campus with Monnie McGee.
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Improving Chemical Modeling for Air Pollution Data . A multivariate receptor model is a latent variable model used to assess the composition and contribution of various pollution sources to an airshed. Dick Gunst is evaluating the effect of temporal dependence and measurement error correlation when using the effective variance solution to the chemical mass balance equations. Multivariate estimators that account for the multiple correlations in the data are under development. |
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Environmental Impact of Automobile Emissions. Automobile and truck emissions are primary sources of atmospheric pollution that contribute to respiratory and other health problems. The complexity of vehicle engine design and operation and of combustion processes make the identification of ways to reduce emissions an exceptionally difficult and expensive task. Dick Gunst has provided expertise on the statistical design and analysis of experiments to automobile manufacturers and major oil companies that contributed to major reductions in vehicle emissions. Recent analyses of data from cooperative studies by both automobile manufacturers and oil companies on the effects of fuel sulfur on emissions has led to tighter EPA standards for permissible levels of sulfur in fuels |
New Data Analysis Tools for Ecology . Bill Schucany in collaboration with Pat Gerard, Mississippi State University, have developed some new techniques and published them in Biometrics and the Journal of Agricultural, Biological, and Environmental Statistics. They have extended the methodology for line-transect sampling in certain environmental settings. These flexible new estimators allow ecologists to more effectively combine such data on the same species of plants or animals from the field with fewer assumptions on the form of the detectability function away from the line. Sergio Juarez in dissertation research with Bill Schucany is evaluating new robust estimators for analyzing excedances over a threshold. The applications involve extremes in ozone measurements.
| Spatial Modeling of Global Temperature Change . Temperature change varies both over time and throughout spatial locations on the globe. Monthly temperature measurements are available for over a century, but the locations of the temperature measurements are concentrated in highly developed countries and some well traveled ocean locations. The lack of a uniform pattern of environmental monitoring stations throughout the globe presents formidable challenges to any attempt to use station data to measure global climatic temperature change. Dick Gunst has developed improved spatial models that accommodate the uneven spatial density of monitoring stations around the globe. These models are contributing to the calculation of more accurate estimates of global temperature change and, equally important, the uncertainty in those estimates. |
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Time Series Analysis of Global Temperatures . These data show a general increase over the past 100 years. There has been considerable controversy in the scientific community concerning whether this trend is a "deterministic" trend that should be predicted to continue or whether it is simply a "random" trending behavior that is part of the natural cycle of temperature changes. Through research funded by the Department of Energy, Wayne Woodward and Buddy Gray have developed methods for assessing whether an observed trend in a time series is deterministic or random.
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Seismic Signal Processing for Nuclear Monitoring. Wayne Woodward and Buddy Gray have been involved with the "ultimate environmental protection problem" of detecting underground nuclear explosions. Through funding from the Department of Defense, they have developed new statistical outlier testing methodology to be used with the data obtained from a global network of seismic stations designed to detect unusual seismic events that may be linked to underground nuclear testing. |
Agricultural Sciences. In other research, Bill Schucany and Pat Gerard have devised a new technique for analyzing the freeze hardiness of plants. They produced a new method for identifying change points in thermal records. These discontinuities, minima, and inflection points can be valuable information for plant scientists investigating the cold tolerance of various species.
