Coupling techniques in boundary-combined methods for solving elliptic problems with singularities

Three coupling strategies in matching the Ritz-Galerkin method and the finite element method are introduced for general elliptic equations, and useful numerical techniques are provided. Numerical experiments have been carried out for solving the typical, singular Motz problem, which shows that optimal convergence rates of numerical solutions can be achieved by using the combined methods and techniques provided in this paper.     

Reproducibility and validity of an extensive semiquantitative food frequency questionnaire among Greek school teachers

The involvement of mental health professionals in determinations of dangerousness is both common and controversial. Among the various contexts for these evaluations, the release of potentially violent forensic patients from maximum security facilities evokes justified concern from involved experts and apprehension to outrage from the immediate community. We sought to examine how conclusions are reached on dangerousness at two sequential stages: clinical recommendations and Manifest Dangerousness Hearings decisions. In an archival study of 245 patients, we found that lack of progress in the institution and physical assaultiveness were the strongest correlates with dangerousness. In contrast, experts and review boards appeared to be relatively less influenced by diagnosis, types of treatment, and sociodemographic variables.     

Inhibition of plasma membrane Ca(2+)-ATPase activity by volatile anesthetics

BACKGROUND: The precise sites and mechanisms of action of volatile anesthetics remain unknown. Recently, several integral membrane proteins have been suggested as potential targets to which anesthetics can bind at hydrophobic regions. Impairment of cell Ca2+ homeostasis has been postulated as one of the possible mechanisms of anesthetic action. To test these hypotheses, the authors selected the human erythrocyte Ca(2+)-ATPase as a model membrane protein. This enzyme is an integral membrane protein that is instrumental in maintaining Ca2+ homeostasis in the cell in which it is the sole Ca(2+)-transporting system. Thus, any functional alteration of the Ca(2+)-ATPase by anesthetics may lead to serious perturbations in Ca(2+)-regulated processes in the cell. METHODS: The Ca(2+)-ATPase activity was measured as a function of increased concentration of four volatile anesthetics: halothane, isoflurane, enflurane, and desflurane. RESULTS: All four anesthetics significantly inhibited the Ca(2+)-ATPase activity in a dose-dependent manner. The half-maximal inhibition occurred at anesthetic concentrations from 0.3 to 0.7 vol% at 37 degrees C, which, except for desflurane, is a clinically relevant concentration range. The greater the clinical potency of the volatile anesthetics studied, the less was the concentration required to inhibit the Ca(2+)-ATPase activity. The inhibition was less at 25 degrees C than at 37 degrees C, which is consistent with direct interactions of the nonpolar interfaces of the enzyme with the nonpolar of the portions of the anesthetics. CONCLUSIONS: The authors' findings indicate that the Ca(2+)-ATPase is a suitable model for investigating the mechanism of action of volatile anesthetics on the integral membrane protein, and that this inhibition may be specific.     

Design and simulation of waveguide electrooptic beam deflectors

Numerical simulation based on the scalar beam propagation method, was used to investigate the performance of waveguide electrooptic beam deflectors. The deflectors under investigation consist of a stack of electrooptically controlled prisms in a waveguide. The results were compared to earlier simplified analysis. It was found that for given overall device dimensions, the number of interfaces between prisms in a prism-type electrooptic deflector has significant influence on the device performance when it is small. To avoid wavefront distortion, unwanted reflection from the interfaces, and asymmetry in the deflection angles caused by small number of interfaces, one should use more than about ten interfaces in a typical deflector. Additional insights of device operation and design issues are discussed     

On the extension of the compositional rule of inference

In this article we introduce an extension of Zadeh's compositional rule of inference in terms of the general rule of inference using a triangular norm extended to n arguments. Using this extension, all inferences schemes, crisp as well as fuzzy, based on the compositional rule of inference can be obtained in a uniform way. © 1993 John Wiley & Sons, Inc.     

Portosystemic shunt in Budd-Chiari syndrome: long-term survival and factors affecting shunt patency in 25 patients in Western countries

BACKGROUND: In Budd-Chiari syndrome (BCS) treated by portosystemic shunt, postoperative shunt thrombosis is associated with high morbidity and mortality rates. The aim of this study was to determine factors associated with shunt thrombosis. METHODS: From 1985 to 1991, 25 patients underwent portosystemic shunt for BCS. According to the patency of the shunt during the postoperative period and follow-up, patients were divided into two groups including 17 patients with patent shunt and 8 (32%) with shunt thrombosis. RESULTS: In patients with patent shunt, actuarial survival rate at 5 years was 87% versus 38% in patients with shunt thrombosis (p < 0.05). Duration of symptoms before operation was higher in patients with shunt thrombosis than in patients with patent shunt (315 +/- 483 vs 109 +/- 168 days, p < 0.05). In patients with patent shunt, extensive fibrosis or cirrhosis was observed in 3 of 17 (18%) versus in 5 of 8 (63%) of patients with shunt thrombosis (p < 0.05). Shunt thrombosis was observed in 3 of 3 patients (100%) with the combination of myeloproliferative disorder, duration of symptoms more than 100 days, and cirrhosis versus 0 of 6 (0%) patients without this combination (p < 0.05). CONCLUSIONS: In acute form of BCS (with short history of the disease and absence of extensive fibrosis or cirrhosis), early portal decompression is mandatory, with low risk of shunt thrombosis and good long-term results. In chronic form of BCS, the risk of shunt thrombosis is high and long-term results are bad; in these patients, orthotopic liver transplantation must be considered.