Critical review of psychometric tests

Macroscopic haematuria is common in IgA nephropathy, but its significance and influence on prognosis remains uncertain. We compared the clinical and pathological features of 11 adult patients with primary IgA nephropathy who had had a renal biopsy during or shortly after a bleeding episode. Six patients developed transient acute renal failure (ARF) (group 1) and five did not (group 2). Patients of group 1 had a higher percentage of tubular red-blood-cell (RBC) casts (P < 0.05) and of glomerular crescents (P < 0.001). However, crescents were focal and involved less than 50% of glomeruli. Acute tubular necrosis was only present in patients of group 1, and ARF was attributed to the acute tubular changes rather than to the glomerular lesions. Despite a prolonged duration of ARF (mean: 38 days), further outcome did not differ in patients of both groups. We suggest that acute tubular damage and/or tubular obstruction by RBC casts should be considered in any patient who develops ARF soon after a haematuric episode.     

Theory of rate-distortion-optimal, constrainedfilterbanks-application to IIR and FIR biorthogonal designs

We design filterbanks that are best matched to input signal statistics in M-channel subband coders, using a rate-distortion criterion. Previous research has shown that unconstrained-length, paraunitary filterbanks optimized under various energy compaction criteria are principal-component filterbanks that satisfy two fundamental properties: total decorrelation and spectral majorization. In this paper, we first demonstrate that the two properties above are not specific to the paraunitary case but are satisfied for a much broader class of design constraints. Our results apply to a broad class of rate-distortion criteria, including the conventional coding gain criterion as a special case. A consequence of these properties is that optimal perfect-reconstruction (PR) filterbanks take the form of the cascade of principal-component filterbanks and a bank of pre- and post-conditioning filters. The proof uses variational techniques and is applicable to a variety of constrained design problems. In the second part of this paper, we apply the theory above to practical filterbank design problems. We give analytical expressions for optimal IIR biorthogonal filterbanks; our analysis validates a conjecture by several researchers. We then derive the asymptotic limit of optimal FIR biorthogonal filterbanks as filter length tends to infinity. The performance loss due to FIR constraints is quantified theoretically and experimentally. The optimal filters are quite different from traditional filters. Finally, a sensitivity analysis is presented     

Evaluation of ductile tearing in cracked pipes and elbows under bending

A major project was launched in France to develop leak-before-break methods applicable to the primary circuit of pressurized water reactors. An important aspect is to be able to calculate the resistance strength of piping components (tube or elbow) that contain a through-wall circumferential crack. This paper presents details of the development of an experimental method that can be used to define J-R curve, using experiments performed on cracked tubes and elbows at room temperature. Applications for components made from ferritic steel and austenitic steels are described. It is concluded that the procedure could be effective for characterizing the real behaviour of cracked pipes or elbows.     

Wall-coated open tubular column coupled with nitrogen-selective detector for routine GLC determination of diazepam, meprobamate, phenylbutazone, and thioridazine in serum

The selectivity and sensitivity provided by a wall-coated open tubular column coupled with a nitrogen-selective detector allowed rapid, accurate determination of diazepam, meprobamate, phenylbutazone, and thioridazine in serum in the same chromatographic system using 100--200 microliters of sample.     

Correction of the Poisson effect in the elastic analysis of low-cycle fatigue

The amount of fatigue damage is very dependent on the cyclic variation in real strain. It is the current practice to use elastic analysis to assess this strain. In low-cycle fatigue conditions, in which inelastic strains are predominant, elastic analysis underestimates the real value of the variation in strain. To make effective use of the results of elastic analysis despite this shortcoming, corrections need to be made. One such correction concerns the Poisson effect, since Poisson's ratio vis higher for inelastic behaviour. In this paper a method for correcting the Poisson effect in the plastic range is proposed. It consists simply of multiplying the result of the elastic computation by a coefficient Kv. A method is developed for determining this coefficient as a function of the result of the elastic computation. It relies on simple analytical calculations and uses the uniaxial cyclic curve of the material. Examples are provided. The proposed procedure is easy to use and very inexpensive.     

Hemostasis in children undergoing liver transplantation

Faculty workload determination formulas are a means by which program directors can justify their time and that of other faculty. This article is written to assist faculty in this necessary yet time-consuming endeavor. A table of calculations (time/activity ratio) for determination of committed hours, examples of actual workload determination, and a worksheet are provided.