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At least 163 records · Page 9Linked to original sources
PubMed1998

Crash risks of older drivers: a panel data analysis.

Considerable progress has been made on understanding older drivers' safety issues. None the less, findings from previous research have been rather inconclusive. Differences in data and research methodology have been suggested as factors that contribute to the discrepancies in previous findings. One of the methodological limitations is the lack of considering temporal order between events (i.e. the time between onset of medical condition, symptom and crash). Without time-series data, a 'snap-shot' of medical conditions and driving patterns were often linked to more than 1 year--of crash data, hoping to accumulate enough data on crashes. The interpretation of the results from these studies is difficult in that one cannot explicitly attribute the increase in highway crash rates to medical conditions and/or physical limitations. This paper uses a panel data analysis to identify factors that place older drivers at greater crash risk. Our results show that factors that place female drivers at greater crash risk are different from those influencing male drivers. More risk factors were found to be significant in affecting older men's involvement in crashes than older women. When the analysis controlled for the amount of driving, women who live alone or who experience back pain were found to have a higher crash risk. Similarly, men who are employed, score low on word-recall tests, have a history of glaucoma, or use antidepressant drugs were found to have a higher crash risk. The most influential risk factors in men were the number of miles driven, and use of antidepressants.

Accidents, Traffic↗
PubMed1978

[Planning and data analysis in prospective controlled clinical trials (author's transl)].

Planning of prospective controlled clinical trials in surgery requires the use of test and control groups, sufficiently frequent repetition of experiments, random allocation of patients to the groups (example), and balancing. The descriptive data analysis should be performed in a stepwise manner (list of new data, rank list, range, median, quartiles, histogram, mean value standard deviation). The advantages of the median-quartile-system and the prerequisites for application of various significance tests are pointed out. In the conduct of controlled clinical trials, the consultative role of experimental surgeons is proposed.

Clinical Trials as Topic↗
PubMed1989

Histopathological classification of dementias by multivariate data analysis.

Autopsied brains from 55 demented patients, clinically classified according to DSM-III criteria into AD/SDAT and MID and 19 nondemented individuals were available for this study. Using general clinical, gross neuroanatomical and histopathological data three separate dementia classes, namely AD/SDAT, MID and AD-MID, were visualized in two-dimensional space by multivariate data analysis. This analysis revealed that the pathology in AD-MID patients were not merely a linear combination of the pathology in AD/SDAT and MID, indicating that AD-MID might represent a dementia type of its own.

Aged↗
PubMed1998

Correlation of human jejunal permeability (in vivo) of drugs with experimentally and theoretically derived parameters. A multivariate data analysis approach.

The effective permeability (Peff) in the human jejunum (in vivo) of 22 structurally diverse compounds was correlated with both experimentally determined lipophilicity values and calculated molecular descriptors. The permeability data were previously obtained by using a regional in vivo perfusion system in the proximal jejunum in humans as part of constructing a biopharmaceutical classification system for oral immediate-release products. pKa, log P, and, where relevant, log Pion values were determined using the pH-metric technique. On the basis of these experiments, log D values were calculated at pH 5.5, 6.5, and 7.4. Multivariate data analysis was used to derive models that correlate passive intestinal permeability to physicochemical descriptors. The best model obtained, based on 13 passively transcellularly absorbed compounds, used the variables HBD (number of hydrogen bond donors), PSA (polar surface area), and either log D5.5 or log D6.5 (octanol/water distribution coefficient at pH 5.5 and 6.5, respectively). Statistically good models for prediciting human in vivo Peff values were also obtained by using only HBD and PSA or HBD, PSA, and CLOGP. These models can be used to predict passive intestinal membrane diffusion in humans for compounds that fit within the defined property space. We used one of the models obtained above to predict the log Peff values for an external validation set consisting of 34 compounds. A good correlation with the absorption data of these compounds was found.

Humans↗
PubMedDate not supplied

Data analysis issues for protocols with overlapping enrollment.

Many persons with HIV require and take several medications. The efficacy and safety of many of these medications are uncertain. Usually limited data on drug interactions are available. Thus simultaneous and sequential enrolment of patients into multiple studies is desired for reasons of science and efficiency. This paper discusses the analysis of data arising from coenrolment in multiple studies sponsored by the Community Programs for Clinical Research on AIDS (CPCRA). Factorial designs and those in which patients are sequentially instead of simultaneously randomized are compared. Approaches to data analysis, based on intention-to-treat, for individual and pairs of trials are described. An antiretroviral trial and a trial for prophylaxis of Pneumocystis carinii pneumonia (PCP) are used for illustration. We conclude that such analyses may yield useful information on drug interactions and that a more vigorous coenrolment policy should be pursued in AIDS research.

AIDS-Related Opportunistic Infections↗
PubMed1996

A review of crash data analysis in a defect and recall investigation of the general motors C/K pickup trucks.

In the process of assessing the safety of the fuel-containment system of the 1973-1987 General Motors C/K truck, the National Highway Traffic Safety Administration and General Motors Corporation have written and submitted numerous documents to a public file between October 1992 and April 1993. Five substantial reports have been issued by the National Highway Traffic Safety Administration and General Motors Corporation describing data analysis of crashes recorded on state and federal databases. Both the National Highway Traffic Safety Administration and General Motors Corporation have used crash data, in some cases the same data, to examine the claim that a defect in the fuel system design of General Motors Corporation C/K trucks poses an unreasonable risk of death or injury. The comparative analysis presented in this paper demonstrates how crash databases and their summary statistics can be used to support opposed positions in a safety dispute. Understanding differences in the analysis is fundamental to obtaining an insight into the role of field crash data, including its relevance and shortcomings, in defect and recall investigations.

Accidents, Traffic↗
PubMed1984

Permutation methods for the structured exploratory data analysis (SEDA) of familial trait values.

A collection of functions that contrast familial trait values between and across generations is proposed for studying transmission effects and other collateral influences in nuclear families. Two classes of structured exploratory data analysis (SEDA) statistics are derived from ratios of these functions. SEDA-functionals are the empirical cumulative distributions of the ratio of the two contrasts computed within each family. SEDA-indices are formed by first averaging the numerator and denominator contrasts separately over the population and then forming their ratio. The significance of SEDA results are determined by a spectrum of permutation techniques that selectively shuffle the trait values across families. The process systematically alters certain family structure relationships while keeping other familial relationships intact. The methodology is applied to five data examples of plasma total cholesterol concentrations, reported height values, dermatoglyphic pattern intensity index scores, measurements of dopamine-beta-hydroxylase activity, and psychometric cognitive test results.

Adolescent↗
PubMed1994

Computer assisted clinical data analysis.

The Diagnosis Related Groups patient classification scheme coupled with desk top PC technology permits sophisticated analysis of patient medical data. Individuals with no programming knowledge can produce sophisticated analysis. The functionality and structure of the 3M Analytical Workstation are described and example analysis reports are presented.

Computer Systems↗
PubMedDate not supplied

A JAVA environment for medical image data analysis: initial application for brain PET quantitation.

Analysis software for medical image data tends to be expensive and usable only in a restricted environment. Therefore the aim of the current project was to implement a flexible framework for medical image processing and visualization which is portable among platforms and open to different data formats including DICOM 3.0. The software was designed as a set of tools which encapsulate specialized functionality. The tools are full stand alone applications, but they are also able to present a co-operating environment within which images and other information are communicated in real time. Currently, the emphasis is on quantitative analysis of PET data by kinetic modelling. However, general viewing capabilities are included, and the design is flexible enough that other types of processing can easily be integrated by simply plugging in Java classes. The software is successfully applied to PET data quantitation in clinical research studies and even patient studies. Portability was aimed at by encoding the programs in Java. Experience shows that the implementation of such a complex and computationally demanding Java application is feasible. Although there are major portability issues to consider, configurations can be found on which the software runs stably and at a speed comparable to C code if just-in-time compilation is available.

Brain↗
PubMed1996

[Transformations of parameters in the generalized Poisson distribution for test data analysis].

The generalized Poisson distribution is a distribution which approximates various forms of mixtures of Poisson distributions. The mean and variance of the generalized Poisson distribution, which are simple functions of the two parameters of the distribution, are more useful than the original parameters in test data analysis. Therefore, we adopted two types of transformations of parameters. The first model has new parameters of mean and standard deviation. The second model contains new parameters of mean and variance/mean. An example indicates that the transformed parameters are convenient to understand the properties of data.

Adult↗
PubMed1998

Absolute metabolite quantification by in vivo NMR spectroscopy: V. Multicentre quantitative data analysis trial on the overlapping background problem.

The goal of this study was to establish the best approach for quantifying nuclear magnetic resonance (NMR) lines, that in the frequency domain are overlapping with broad, unwanted background features. To perform the quantitative data analysis in a controlled way, test signals were designed and utilised, derived from two different real-world in vivo nuclear magnetic resonance signals. One of the main conclusions of the study was that the quantification methods currently available to the biomedical research groups can deliver the correct values of the quantitative parameters, but that great care should be taken in using optimal input parameters for the computer programs concerned.

Bayes Theorem↗
PubMed1984

An assay for pattern formation in dictyostelium discoideum using monoclonal antibodies, flow cytometry, and subsequent data analysis.

An assay for determining the proportions of prespore cells in a simple multicellular organism, the slug stage of Dictyostelium discoideum, was established using a prespore-specific monoclonal antibody and a fluorescence-activated cell sorter. Appropriate techniques for data analysis were developed. The effects of slug size and age were determined. Small slugs have a lower percentage of prespore cells than large slugs. The percentage of prespore cells increases and then decreases in slugs aged between a few hours and 9 days. Pronounced effects were observed on the size of cells in aging slugs. In particular unlabelled (mostly prestalk) cells were larger than prespore cells in young slugs, but after 6 days migration they became considerably smaller than prespore cells. The fact that all unlabelled cells were coordinately shifted in size, suggests that these cells (which comprise prestalk, prestalklike, and predisc cells) are related to each other.

Antibodies, Monoclonal↗
PubMed1992

Clinical assessment of the knowledge base of an expert system for data analysis in laboratory medicine.

Despite the apparent demand for a consultation system, only a few expert systems have been developed for laboratory medicine. Some studies on the diagnostic precision of such systems have been reported, but the efficiency of their knowledge bases has not yet been investigated. An expert system, named BLOOD, for data analysis in a hematology laboratory, which is written in C-Prolog and runs on VAX-station, has already been reported to have excellent diagnostic reliability and ability to cope with the fuzziness involved in clinical diagnostic procedures. A quantitative examination of the knowledge base of BLOOD using real laboratory data from 58 patients diagnosed as having iron deficiency anemia clearly revealed the verbosity of the knowledge base, and proved that it was effective for obtaining a group of essential diagnostic rules.

Anemia, Hypochromic↗
PubMed1981

[Data analysis in health insurance].

In the last fifty years four to six mathematical research endeavours of general significance only have been designed in the field of health insurance. It is inconsequent to discuss the changes needed in the insurance system without having at one's disposal minimal mathematically-statistically firm basic figures. The present work first generally defines the mathematical bases in the health insurance field. The purpose of the project, within the first large scale data analysis, is above all the development of concepts for the institutionalized, systematic and periodical exploitation of the data available to health insurance carriers and their testing with econometric models. At the same time, thanks to methods to regularly collect data in the various health care sectors, the dependence of cost factors on medical care supply, on the structure of the insured population and on the cost causes will be studied at periodic intervals. Cheap sampling concepts shall be developed and tested in order to obtain the data which are not gathered directly. In a few fields data collection through surveys will be organized in order to allow for comprehensive interdisciplinary interpretation of the data.

Health Services↗
PubMed1983

Structured exploratory data analysis (SEDA) of finger ridge-count inheritance: I. Major gene index, midparental correlation, and offspring-between-parents function in 125 south Indian families.

Fourteen dermatoglyphic traits measured on 125 Velanadu Brahmin families were analyzed for mode of inheritance using three Structured Exploratory Data Analysis (SEDA) statistics: the major gene index, the offspring between parents function, and the traditional midparental correlation coefficient. Since the traits are integer valued with restricted ranges of variation, we simulated various transmission models with discrete expression to better understand the nature of the SEDA statistics for such variables. In addition, permutation procedures were employed to aid the interpretation of the SEDA results. These analyses suggest that corresponding homologous fingers on the left and right hands exhibit similar transmission characteristics. The relationship of the parent and child total ridge-counts of the two hands separately, as well as their combined total, virtually simulate complete Galtonian blending inheritance. Results for the individual digital ridge-counts as well as the pattern-intensity-index variable also suggest a multifactorial mode of transmission or possibly one involving several genes.

Dermatoglyphics↗
PubMed1982

Interactive computer programs in sequence data analysis.

We present interactive computer programs for the analysis of nucleic acid sequences. In order to handle these programs, minimum computer experience is sufficient. The nucleotide sequence of the human gamma globin gene complex is used as an example to illustrate the data analysis.

Base Sequence↗
PubMed1994

Categorical data analysis of the effect on bull fertility of butylated hydroxytoluene addition to semen extenders prior to freezing.

Butylated hydroxytoluene is an antioxidant that has antiviral properties and sustains sperm viability during freezing and thawing. A field trial involving 11 bulls and 19,000 AI was conducted to determine whether addition of .5 mM butylated hydroxytoluene to whole milk extender during seminal processing affected bull fertility as estimated by nonreturn rates generated by cows bred to the bulls. Effects of bull, batch of semen nested within bull, treatment, and month of AI were studied. Nonreturn rates were recorded for each month for every bull, batch of semen (ejaculates pooled on a given day), and treatment combination. Because some bulls had < 6 batches of semen, the original experimental design was reduced to two smaller designs. Categorical data analysis with maximum likelihood estimation was used for analysis of nonreturn rates. The results from three models were used to interpret the data. The nonreturn rates were approximately 73.9% for the butylated hydroxytoluene treatment and 74.1% for the control. In all models, bull effect was significant, but batch, month of AI, and treatment had no effect on bull fertility. Addition of .5 mM butylated hydroxytoluene to whole milk extender during semen processing did not affect bull nonreturn rates.

Animals↗