The boundary contour method for two-dimensional Stokes flow and incompressible elastic materials

 A variant of the boundary element method, called the boundary contour method (BCM), offers a further reduction in dimensionality. Consequently, boundary contour analysis of two-dimensional (2-D) problems does not require any numerical integration at all. While the method has enjoyed many successful applications in linear elasticity, the above advantage has not been exploited for Stokes flow problems and incompressible media. In order to extend the BCM to these materials, this paper presents a development of the method based on the equations of Stokes flow and its 2-D kernel tensors. Potential functions are derived for quadratic boundary elements. Numerical solutions for some well-known examples are compared with the analytical ones to validate the development. Received 28 August 2001 / Accepted 15 January 2002     

Achievable performance over the correlated Rician channel

The correlated Rician channel is a useful model for a slowly fading channel, in which the complex fading process is composed of two quadrature Gaussian processes with a given autocorrelation function. For slow fading the correlation between adjacent symbols is relatively high. The authors investigate the achievable error probabilities over the channel, employing coherent detection and ideal side information on the realization of the fading processes at the receiver. An underlying decoding delay constraint which precludes the use of (ideal) interleaving is assumed. Coded BPSK performance is addressed both with and without the piecewise constant approximation (according to which the fading value remains constant during the symbol duration). For the latter case, that is no piecewise constant approximation, the analysis relies on the Fredholm determinant associated with the fading process autocorrelation function. The authors focus on the exponentially correlated channel. The “worst case” pairs of codewords are identified. The exponential behavior of the error probability with random coding (and i.i.d. Gaussian inputs) is analyzed, and the behavior of the cut-off rate and capacity is addressed. The results enhance the insight to the effect of the basic parameters governing the performance and these are examined in view of previous works and compared to relevant performance results for the block-fading channel model     

A behavioral probe of the growth of intake potential during the inter-meal interval in the rat.

The rat's willingness to ingest glucose after an initial intraoral intake test was probed by beginning a 2nd intraoral intake test at variable durations (1–220 min). In Exp 1, after an initial meal of 12.5% glucose solution averaging 26.9?±?1.7 ml, the size of the 2nd (probe) meal of the same stimulus increased linearly from 4.0?±?0.9 ml after a 1-min delay to 15.4?±?2.7 ml after a 120-min delay. In Exp 2, intraoral intake of a more concentrated (37.5%) glucose solution rose more slowly as a function of delay from 2.4?±?2.7 ml to 4.9?±?0.6 ml. For each glucose concentration, the linear recovery function and a slope that depends on stimulus concentration are consistent with a role for gastric emptying during the delay in intake recovery. In Exp 3, rats ingested 12.5% or 37.5% glucose to satiety in an initial test and received, after a variable delay, either the same or the other concentration as the probe stimulus. The same volumes were ingested at each delay whether the glucose concentration of the probe stimulus was the same or was switched from that presented in the initial test. This result shows that the taste and caloric properties of the probe stimulus played no role in determining how much of it would be ingested… (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Application of a general health policy model in the American health care crisis

There is near consensus that the US health care system requires reform. Only a quarter of the American public has faith in the current system. Health care was one of the major issues considered in the 1992 US presidential election and the search for innovative solutions has transcended administrations.     

Study of isolated apparent amniogenic limb deficiency in Hungary, 1975-1984

Rat brain cortex slices and synaptosomes preincubated with [3H]noradrenaline were used to investigate whether the NMDA-evoked noradrenaline release is modulated by agonists or antagonists at presynaptic alpha 2-adrenoceptors. In experiments on slices, noradrenaline and the preferential alpha-adrenoceptor agonists talipexole (former B-HT 920) and clonidine inhibited the NMDA-evoked tritium overflow whereas the selective alpha 1-adrenoceptor agonists cirazoline and methoxamine were ineffective. The alpha 2-adrenoceptor antagonists rauwolscine and idazoxan facilitated the NMDA-evoked tritium overflow whereas the preferential alpha 1-adrenoceptor antagonist prazosin was ineffective. The concentration-response curve of talipexole for its inhibitory effect on NMDA-evoked overflow was shifted to the right by idazoxan (apparent pA2 = 7.5). The EC50 of NMDA (97 mumol/l) for its stimulating effect on tritium overflow was not substantially changed by blockade of alpha 2-autoreceptors with 1 mumol/l rauwolscine (EC50 of NMDA in the presence of the alpha 2-adrenoceptor antagonist, 155 mumol/l), but the maximal overflow of tritium was increased 2.5 fold by this rauwolscine concentration. In experiments on synaptosomes, talipexole and noradrenaline inhibited the NMDA-evoked tritium overflow. The inhibitory effect of talipexole was abolished by idazoxan which, given alone, was ineffective, as was prazosin. Talipexole did also not produce an inhibition when tritium overflow was evoked by NMDA in the presence of omega-conotoxin GVIA 0.1 mumol/l; the latter, by itself, decreased the response to NMDA by about 55%.(ABSTRACT TRUNCATED AT 250 WORDS)     

Serogrouping of Bacteroides nodosus isolates from 62 sources in the United States

Bacteroides nodosus isolates from 62 sources in the United States were obtained from sheep with infectious foot diseases. Serotypic analysis of these isolates revealed 21 serotypes (designated I-XXI). These serotypes were compared with British and Australian/New Zealand B nodosus strains by use of reciprocal tube agglutination tests. These tests, as well as the cross-matching tube agglutination tests of the US serotypes, resulted in arranging the US serotypes into 11 serogroups, and comparing these serogroups with their Australian/New Zealand serogroup and British serotype counterparts. Three US serogroups and 1 additional British serotype had little or no relationship to any of the Australian/New Zealand serogroups A-H (the vaccine strains). One or more of these unrelated serogroups were found in 29% of the sources studied. The most frequently found US serotype was serotype XV at 29%. The most frequently found US serogroups were the serogroups analogous to serogroup B (43.5%) and serogroup H (37%); the other serogroups were found in 22.6% or less of the sources studied. Evaluation of 3 sources revealed that multiple serotypes in a single flock are common, multiple serotypes from a single lesion are possible, B nodosus isolates obtained from goats (unlike those from cattle) appear identical to the isolates obtained from sheep, and disease can appear in vaccinated animals, even in a flock that appears to be harboring only a single serogroup-B serotype (the serogroup for which there are 3 strains in the current vaccine).     

Parkinson's disease. Second of two parts

At no time in the past have the basic and clinical sciences applied to Parkinson's disease been so active. Experimental therapies under study at present promise to improve on the limitations of existing treatments. Future progress in understanding the causation and pathogenesis of the disorder will permit the development of new treatments that will slow, halt, or even reverse the currently inexorable progressive course of Parkinson's disease.     

Self-efficacy expectations predict survival for patients with chronic obstructive pulmonary disease.

Evaluated the validity of self-efficacy expectations as predictors of mortality for 119 patients with chronic obstructive pulmonary disease. Ss completed 4 physiological measures that represent common clinical indicators of disease severity: forced expiratory volume in 1 s(FEV1.0), arterial blood gas measurement of resting partial pressure of oxygen (PaO?), single-breath diffusing capacity (DLCO), and maximum oxygen uptake (V02max) during exercise. In addition, self-reported self-efficacy expectation for walking on a treadmill was measured. Self-efficacy was a significant univariate predictor of 5-yr survival. However, when controlling for FEV1.0 in multivariate survival analysis, self-efficacy had only a marginal effect. Simple self-report scales may provide significant information about health status. (PsycINFO Database Record (c) 2010 APA, all rights reserved)