Alpha Air Sample Counting Efficiency Versus Dust Loading: Evaluation of a Large Data Set.

Dust loading on air sample filters is known to cause a loss of efficiency for direct counting of alpha activity on the filters, but the amount of dust loading and the correction factor needed to account for attenuated alpha particles is difficult to assess. In this paper, correction factors are developed by statistical analysis of a large database of air sample results for a uranium and plutonium processing facility at the Savannah River Site. As is typically the case, dust-loading data is not directly available, but sample volume is found to be a reasonable proxy measure; the amount of dust loading is inferred by a combination of the derived correction factors and a Monte Carlo model. The technique compares the distribution of activity ratios [beta/(beta + alpha)] by volume and applies a range of correction factors on the raw alpha count rate. The best-fit results with this method are compared with MCNP modeling of activity uniformly deposited in the dust and analytical laboratory results of digested filters. A linear fit is proposed to evenly-deposited alpha activity collected on filters with dust loading over a range of about 2 mg cm to 1,000 mg cm.

Experimental systems implementation of a hybrid optical-digital correlator.

A high-speed hybrid optical-digital correlator system was designed, constructed, modeled, and demonstrated experimentally. This correlator is capable of operation at approximately 3000 correlations/s. The input scene is digitized at a resolution of 512 x 512 pixels and the phase information of the two-dimensional fast Fourier transform calculated and displayed in the correlator filter plane at normal video frame rates. High-fidelity reference template images are stored in a phase-conjugating optical memory placed at the nominal input plane of the correlator and reconstructed with a high-speed acousto-optic scanner; this allows for cross correlation of the entire reference data set with the input scene within one frame period. A high-speed CCD camera is used to capture the correlation-plane image, and rapid correlation-plane processing is achieved with a parallel processing architecture.

Compact phase-conjugating correlator: simulation and experimental analysis.

A simulation and experimental investigation of a recently proposed, compact, phase-conjugating correlator is undertaken. The effects of noise and other distortions in the input image and in the correlator filter plane are considered. As with other phase-only designs, the phase-conjugating correlator is sensitive to distortion of the input image while being robust in the presence of filter-plane distortions; this robustness is enhanced by the phase-conjugating property of the design.

Interaction of multiple distortions in spatial light modulators.

Spatial light modulators are the key components in real-time optical image-processing systems. The phase and the intensity of their outputs will often depart from ideal behavior. An experimental method is described that permits the effects of multiple distortions, present simultaneously, to be modeled. A computer simulation of a bismuth silicon oxide-based correlator is presented, with spatial light modulators subject to three types of distortion, including phase and amplitude. The experimental method permits both the main effects of the distortions and their interactions to be predicted. Combining all the distortions simultaneously gives a more accurate assessment of the suitability of a spatial light modulator for a given optical processing task. Images of 256 × 256 pixels were used, and the simulation took 15 min. with a Sun SPARCstation 2.

Factors influencing the adoption and maintenance of Canadian, facility-based worksite health promotion programs.

PURPOSE: The purpose of this study was to determine senior management's rationale for adopting and maintaining worksite health promotion programs and the congruence of this rationale with the program objectives of health professionals who manage the programs. DESIGN: A multiple case study design was used. SETTING: Nine major Canadian organizations which had adopted facility-based health promotion programs were the settings for this study. DATA COLLECTION: Semi-structured interviews (22 conducted) and two questionnaires (36 completed) were the methods used to collect data. RESPONDENTS: Senior managers involved in program adoption, senior managers responsible for program budgets, and senior health professionals responded to the interviews and questionnaires. RESULTS: Impetus for health promotion program adoption in the organizations we studied had more to do with tangential issues such as an organization moving to a new facility or having access to unused space than with employee health or organizational performance considerations. The most common program adoption rationale was related to employee recruitment/retention. Program continuance was based on process issues such as participation rates and the quality of activity offerings rather than on health or organizational outcomes. While health professionals and senior management both considered human relations and morale more important than cost savings outcomes, health professionals considered cost savings outcomes more important than did senior management. CONCLUSIONS: It is important for health promotion professionals to develop program objectives which are shared by organizational management. Future program adoptions and maintenance will be influenced by closer analyses of the effect of these programs on organizational performance.

Reinstitution of neuroleptic treatment with molindone in a patient with a history of neuroleptic malignant syndrome.

The decision to reinstitute neuroleptic treatment in patients with a history of neuroleptic treatment is fraught with hazards. A case is reported in which neuroleptic treatment was successfully reintroduced with molindone after previous bouts of neuroleptic malignant syndrome (NMS) with trifluoperazine and thioridazine. Molindone may represent an alternative neuroleptic to consider in patients with a history of NMS, although all neuroleptics including clozapine and molindone may potentially precipitate this syndrome.

Idiopathic membranoproliferative (mesangiocapillary) glomerulonephritis: a clinicopathologic study.

In 51 patients with type 1 and 9 patients with type 2 membranoproliferative glomerulonephritis, we found a male predominance in both types, a wide age range but with younger patients having predominantly type 2 disease, and clinical presentations that varied and included the nephrotic syndrome, an abnormal urinalysis only, acute nephritis, and recurrent hematuria. Hypertension and impaired renal function at the time of first evaluation, which were present in more than one-third of the patients, presaged a poor prognosis; in most of these patients end-stage renal failure or worsening of renal function occurred. Acute nephritis at onset was also related to a deteriorating course and was especially frequent in patients with type 2 membranoproliferative glomerulonephritis. Retrospective analysis of treatment regimens, in which patients were given an average of 1 year of therapy with prednisone alone or combined with cytotoxic agents, showed no effect in patients who had progressive forms of the glomerulopathy.

Normal renal function: CIN and CPAH in healthy donors before and after nephrectomy.

To establish normal values for glomerular filtration rate and effective renal plasma flow for age and sex, the records of 141 healthy renal transplant donors were reviewed. These patients had no history of renal or systemic disease, had normal physical examinations, and had normal laboratory studies in addition to having studies of the clearances of insulin (Cin) and para-amino hippurate (Cpah) preoperatively. Regression analysis of the clearance data revealed no significant sex differences in renal function. A linear age-related decline in renal function begins in the 20's and decreases by 4 ml/min per decade for Cin and by 35 ml/min per decade for Cpah through the 60's, our oldest patients studied; therefore, the absolute lower limits of normal (lower fifth percentile) for Cin and Cpah were calculated as a function of age. Residual function was constant with average postoperative clearances 70% of preoperative values regardless of age.