Interrelationships among everyday memory tests: Stability of factor structure with age.

Conducted an experiment in which 158 normal adults (aged 18–77 yrs) completed a battery of tests employing computer and laser-disk technology to simulate learning and memory tasks encountered in daily life. The tests were based on different experimental paradigms and were designed to assess multiple variables related to memory performance across the adult age span. Principal components analyses yielded factors of general memory, attention, and psychomotor speed. The factors remained essentially unchanged when scores were residualized to account for differences in performance related to age. Clinical and research applications of the battery are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

X-Ray Lithography Mask Metrology: Use of Transmitted Electrons in an SEM for Linewidth Measurement

X-ray masks present a measurement object that is different from most other objects used in semiconductor processing because the support membrane is, by design, x-ray transparent. This characteristic can be used as an advantage in electron beam-based x-ray mask metrology since, depending upon the incident electron beam energies, substrate composition and substrate thickness, the membrane can also be essentially electron transparent. The areas of the mask where the absorber structures are located are essentially x-ray opaque, as well as electron opaque. This paper shows that excellent contrast and signal-to-noise levels can be obtained using the transmitted-electron signal for mask metrology rather than the more commonly collected secondary electron signal. Monte Carlo modeling of the transmitted electron signal was used to support this work in order to determine the optimum detector position and characteristics, as well as in determining the location of the edge in the image profile. The comparison between the data from the theoretically-modeled electron beam interaction and actual experimental data were shown to agree extremely well, particularly with regard to the wall slope characteristics of the structure. Therefore, the theory can be used to identify the location of the edge of the absorber line for linewidth measurement. This work provides one approach to improved x-ray mask linewidth metrology and a more precise edge location algorithm for measurement of feature sizes on x-ray masks in commercial instrumentation. This work also represents an initial step toward the first SEM-based accurate linewidth measurement standard from NIST, as well as providing a viable metrology for linewidth measurement instruments of x-ray masks for the lithography community.     

Factor structure of the Wechsler Memory Scale—Revised within a comprehensive neuropsychological battery.

Performed 2 principal factor analyses to examine the construct validity of the Wechsler Memory Scale—Revised (WMS—R) and to determine whether abstraction and memory factors can be extracted from the Halstead-Reitan Neuropsychological Test Battery (HRNB) results. Results from 237 patients support the validity of the verbal memory, delayed recall, and attention and concentration indices of the WMS—R but not the visual memory indices. No separate abstraction factor was found, and none of the HRNB measures loaded substantially on the memory factors defined by WMS—R subtests. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The relationship between accelerating voltage and electron detection modes to linewidth measurement in an SEM

The basic premise underlying the use of the scanning electron microscope (SEM) for linewidth metrology in semiconductor research and production applications is that the video image acquired, displayed, analyzed, and ultimately measured accurately reflects the structure of interest. However, it has been clearly demonstrated that image distortions can be caused by the detected secondary electrons not originating at the point of impact of the primary electron beam and by the type and location of the secondary electron detector. These effects and their contributions to the actual image or linewidth measurement have not been fully evaluated. Effects due to uncertainties in the actual location of electron origination do not affect pitch (line center-to-center or similar-edge-location-to-similar-edge-location spacing) measurements as long as the lines have the same edge geometries and similar profiles of their images in the SEM. However, in linewidth measurement applications, the effects of edge location uncertainty are additive and thus give twice the edge detection error to the measured width. The basic intent of this work is to demonstrate the magnitude of the errors introduced by beam/specimen interactions and the mode of signal detection at a variety of beam acceleration voltages and to discuss their relationship to precise and accurate metrology.     

Using sine wave histograms to estimate analog-to-digital converterdynamic error functions

This paper describes a new method for developing analog-to-digital converter (ADC) error function models using modified sinewave histogram methods. The error models may be used to digitally compensate for nonlinearities introduced by the converter. The histogram modification involves sorting of converter output samples based upon an estimated associated input derivative signal. This error model is based upon a previously unpublished result which shows that sinewave histograms yield distinctly different expected errors for each state based upon input signal slope associated with each output sample. This result thus provides a dynamic dependence for expected errors measured by means of histogram methods. Sorted sinewave histograms are used to estimate slope dependent expected errors at each ADC output state (code). The method provides improved error representation by providing error basis functions for every output code. Simulated results prove that this method removes all slope dependent errors for complex ADC architectures while experimental results for an 8-bit 200 MSPS ADC yielded more than 10 dB improvement in spurious-free-dynamic-range (SFDR) over the full Nyquist band. The new method is thus shown to possess wideband dynamic error character     

Women's perceptions of quality and benefits of postpartum care

Increased competition in the United States has led to increased interest in women's perceptions of their obstetric experience. Family-centered postpartum care (FCPPC) was originated to improve women's perceptions of care quality. This study examined differences in and the hypothesized relationship between quality and beneficence in a group receiving traditional postpartum care (TPPC) and a group receiving FCPPC in a safety-net hospital in West Tennessee. Both groups had high mean quality and beneficence scores; however, the FCPPC group's scores were significantly higher than those of the TPPC group. There was a relationship between quality and beneficence for the combined sample. The findings suggest that nurses should incorporate FCPPC approaches as a means of improving perceived quality and benefits.     

Comparative hemodynamic, left ventricular functional, and antiadrenergic effects of chronic treatment with metoprolol versus carvedilol in the failing heart

BACKGROUND: The basic pharmacology of the third-generation beta-blocking agent carvedilol differs considerably from second-generation compounds such as metoprolol. Moreover, carvedilol may produce different, ie, more favorable, clinical effects in chronic heart failure. For these reasons, we compared the effects of carvedilol and metoprolol on adrenergic activity, receptor expression, degree of clinical beta-blockade, hemodynamics, and left ventricular function in patients with mild or moderate chronic heart failure. METHODS AND RESULTS: The effects of carvedilol versus metoprolol were compared in two concurrent placebo-controlled trials with carvedilol or metoprolol that had common substudies focused on adrenergic, hemodynamic, and left ventricular functional measurements. All subjects in the substudies had chronic heart failure resulting from idiopathic dilated cardiomyopathy. Carvedilol at 50 to 100 mg/d produced reductions in exercise heart rate that were similar to metoprolol at 125 to 150 mg/d, indicating comparable degrees of beta-blockade. Compared with metoprolol, carvedilol was associated with greater improvement in New York Heart Association functional class. Although there were no significant differences in hemodynamic effects between the carvedilol and metoprolol active-treatment groups, carvedilol tended to produce relatively greater improvements in left ventricular ejection fraction, stroke volume, and stroke work compared with changes in the respective placebo groups. Carvedilol selectively lowered coronary sinus norepinephrine levels, an index of cardiac adrenergic activity, whereas metoprolol did not lower coronary sinus norepinephrine and actually increased central venous norepinephrine levels. Finally, metoprolol was associated with an increase in cardiac beta-receptor density, whereas carvedilol did not change cardiac beta-receptor expression. CONCLUSIONS: The third-generation beta-blocking agent carvedilol has substantially different effects on left ventricular function, hemodynamics, adrenergic activity, and beta-receptor expression than dose the second-generation compound metoprolol. Some or all of these differences may explain the apparent differences in clinical results between the two compounds.