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G Wade

Publications and source records attributed to G Wade.

12 recordsLinked to original sources
PubMed1991

An iterative algorithm for scanning tomographic acoustic microscopy.

Acoustic microscopy is capable of providing high-resolution images of small objects. When such a microscope operates in the transmission mode, it produces simply a shadow-graph of all the structures encountered by the acoustic wave passing through the object. The resultant images are difficult to comprehend because of diffraction and overlapping of complex structures. Scanning tomographic acoustic microscopy (STAM) overcomes these difficulties and produces unambiguous micrographs of objects of substantial thickness and complexity. STAM uses the back-and-forth propagation algorithm to reconstruct tomograms of various layers to be imaged. When these layers are physically close to one another, ambiguities appear in the reconstructed images. Using an iterative algorithm eliminates these ambiguities and resolves layers that are only two wavelengths apart.

Algorithms↗
PubMed1990

A randomized double-blind, cross-over study of the linear and nonlinear algorithms for the QT sensing rate adaptive pacemaker.

We have compared the pacing rate responses during cardiopulmonary exercise testing in 11 patients (mean 59 years, six female) with implanted QT sensing rate adaptive pacemakers who were randomly programmed to 1-month periods in the linear and nonlinear algorithms using a double-blind, cross-over design. Exercise testing was performed at the end of each month block and symptoms were scored with the MacMaster questionnaire. With exercise, the time to a 10 beats/min increment in rate was significantly less with the nonlinear compared to the linear algorithm (126 sec vs 255 sec, P = 0.02) but there were no significant differences in exercise duration, the peak pacing rate, the peak VO2, the VO2 at the anaerobic threshold or the mean correlation coefficients of the pacing rate VO2 relationship. Rate oscillation occurred in seven patients in the linear algorithm and in two patients in the nonlinear setting. Initial deceleration of the pacing rate at the onset of exercise occurred in seven patients in the linear algorithm and in four patients in the nonlinear setting. The nonlinear algorithm is associated with a faster response time during exercise and fewer instances of rate instability. However, it has not overcome the problem of a dip in the pacing rate at the beginning of exercise. The major difference in the function of the two algorithms is faster initial acceleration with the nonlinear algorithm. This is explained by the significantly higher values of the slope setting at the lower rate limit for the nonlinear versus the linear algorithm (6.3 ms/ms vs 5.1 ms/ms).

Adult↗
PubMed1990

Effects of lateral ball location, grade, and sex on catching.

To investigate the effects of lateral movement on the quality and quantity of catching as they interact with age, 108 children from Kindergarten through Grade 4 were tested. A ramp was constructed which slowed the descent of the 4-in. fleece ball so that it took 1.8 sec. to arrive at the child's location. Each ball could be delivered to one of five different locations in relation to the child. The child practiced five times, with balls coming in a random sequence to each location, the center of the ramp, 1 ft. and 2 ft. each to the right and left of the center. An increase in number of catches made and in the quality of the performance based on McClenaghan and Gallahue's evaluation were associated with grade. The locations 2 ft. from the center produced the fewest catches within a grade, but 1 ft. from center produced more catches from kindergarteners than the center location and occasionally for upper grades. Evaluations of the performances showed a steady improvement across grades, but there was no effect on the evaluation of catching performance of ball location within a grade. Children appear to be at a preferred stage.

Attention↗
PubMed1989

Body mass as a determinant of seat belt use.

Prevention of death and injury from motor vehicle accidents depends in part on seat belt use. Understanding the determinants of seat belt use is important for developing strategies to increase seat belt use. The cross-sectional association between body mass index (BMI) and self-reported seat belt use was analyzed using data from 3,140 Health Risk Appraisals completed by Tennessee residents during 1986. Persons in the lowest quintile BMI (less than or equal to 21.8 kg/m2) stated they use seat belts 63% (SD = 38%) of the time compared to persons in the highest BMI quintile (greater than or equal to 29.0 kg/m2) who reported using seat belts 50% (SD = 38%) of the time. BMI remained associated with seat belt use after adjustment for age, sex, race, education, cigarette use, alcohol use, drug use, urban/rural residence, state area of residence, miles driven per year, self-reported physical activity, and satisfaction with life. For a 1 kg/m2 increase in BMI, seat belt use declined -0.73% (95% CI = -1.01, -0.46), and the relative odds of not being a frequent seat belt user increased 3% (odds ratio 1.03, 95% CI = 1.01, 1.05). BMI was the third variable selected in a step-wise multiple linear regression after education and race. The BMI/seat belt association, if causal, has implications for (1) targeting of education programs to likely nonusers by traffic safety agencies; (2) targeting health promotion messages to likely nonusers by primary care providers; and (3) design of automobile seats and restraint devices.

Body Weight↗
PubMed1989

Derivation and validation of a decision rule for predicting seat belt utilization.

Information from 3,108 health risk appraisals completed by Tennessee residents in 1986 was used to develop a decision rule for predicting seat belt utilization. The data set was randomly divided into derivation and validation sets. The dependent variable was self-reported seat belt use (percentage). Using multiple linear regression, the following rule was derived: score = [age (years) X 0.24] + [mood-affecting drug use X 4.09] + [miles driven per year X 5.08] + [education level X 11.18] - [race X 18.31] - [cigarette use X 2.73] - [satisfaction with life X 3.50] - [body mass (kg/m2) X 0.83] - [urban/rural residence X 4.08]. Likelihood ratios for persons stating 0 to 25 percent seat belt use were compared with those for persons stating 76 to 100 percent use. The prevalence of 0 to 25 percent seat belt use was 31 percent in the derivation set and 33 percent in the validation set. At the lowest quintile of score (-1 or less), the likelihood ratios were 4.18 and 3.31 in the derivation and validation sets, respectively. At the highest quintile of score (26 or more) the likelihood ratios were 0.29 and 0.38, respectively. At score levels less than 10 the decision rule had a sensitivity of 59 percent and 55 percent and a specificity of 80 percent and 81 percent in the derivation and validation sets, respectively. This decision rule may be used by primary care physicians to identify persons likely not to use seat belts and target them for health promotion efforts.

Choice Behavior↗
PubMed1988

Adapting parametric acoustic arrays for tomographic imaging.

In this paper, we present a theoretical model of a parametric array for tomographic applications. The array in the model is assumed to extend right up to the receiver and its cross section is assumed not to be negligible. These two assumptions have not been previously made in applications concerned with tomography. We invoke conditions that permit the derivation of a simple relation for tomographic reconstruction of variations in the acoustic nonlinear parameter throughout the cross section of an object.

Humans↗
PubMed1988

The pathology of intrauterine thyrotoxicosis: two case reports.

The autopsy findings are described in two infants of hyperthyroid mothers in whom the clinical symptomatology, laboratory data, and autopsy findings strongly suggested intrauterine thyrotoxicosis secondary to transplacental thyroid-stimulating immunoglobulin. Documented intrauterine thyrotoxicosis is extremely rare, and we believe these to be the first detailed pathologic descriptions of the entity. Autopsy findings included slim habitus, massive thyromegaly, hypertrophic cardiomegaly, congestive visceromegaly, pulmonary hypertension, adenopathy, and prominent amniotic fluid aspiration. Both cases illustrate the positive contribution that a carefully performed autopsy, even in the severely macerated stillborn, can make toward better understanding of intrauterine disease.

Adult↗
PubMed1988

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