Digital subtraction radiography requires close matching of the contrast in the films to be subtracted. A digital melhod is presented permitting the retrospective correction of film contrast differences. The method is nonparanietric and derives the required gray level transformation directly from the histograms associated with the radiographs. This transform is shown to be unique and monotonic. ...

PURPOSE This study examined the use of the Tucker linear equating method in producing an individual student's score in 3 groups with bridging stations over 3 consecutive days of the clinical performance examination (CPX) and compared the differences in scoring patterns by bridging number. METHODS Data were drawn from 88 examinees from 3 different CPX groups-DAY1, DAY2, and DAY3-each of which ...

A novel approach to quantifying postural stability in single leg stance is assessment of time-to-boundary (TTB) of center of pressure (COP) excursions. TTB measures estimate the time required for the COP to reach the boundary of the base of support if it were to continue on its instantaneous trajectory and velocity, thus quantifying the spatiotemporal characteristics of postural control. Our pu...

In Table 4, the values for mean and standard deviation are incorrect. Please see the corrected Table 4 here.

Hungry, unrestrained rats (N = 7) were rewarded for pressing a response beam in excess of 11 different force requirements. Changes in peak force production as a function of peak force requirement were examined by analyses of the first four moments of distributions of peak response forces: constant error, the within-subject standard deviation, skewness, and kurtosis. Results were similar to thos...

A new approach for predicting a wide range of physical and thermodynamic properties is proposed. It involves calculation of the molecular descriptors of a target compound of unknown properties, followed by regression of this vector of molecular descriptors versus a database of compounds with known descriptors and measured properties. The regression model, obtained for the descriptors of a targe...

OBJECTIVES Few studies have explicitly tested whether the health disadvantage among older blacks is consistent across the entire range of education. We examined racial differences in the cross-sectional association of education with physical and cognitive function performance in older adults. METHODS Participants included over 9500 blacks and whites, aged ≥ 65 years, from the Chicago Health a...

In the absence of relevant prior experience, popular Bayesian estimation techniques usually begin with some form of "uninformative" prior distribution intended to have minimal inferential influence. Bayes rule will still produce nice-looking estimates and credible intervals, but these lack the logical force attached to experience-based priors and require further justification. This paper concer...

Assume that we observe a small set of entries or linear combinations of entries of an unknown matrix A0 corrupted by noise. We propose a new method for estimating A0 which does not rely on the knowledge or an estimation of the standard deviation of the noise σ. Our estimator achieves, up to a logarithmic factor, optimal rates of convergence under the Frobenius risk and, thus, has the same predi...