Parallelism and the perception of illusory contours

The role of symmetry in the perception of illusory contours has been a subject of controversy ever since Kanizsa proposed his theory of illusory contours based on Gestalt principles. Today it is widely agreed that illusory contours do not necessarily occur more readily with inducers that can be 'amodally' completed to symmetrical objects than with inducers that cannot. But the question of whether symmetrical inducers produce weaker illusory contours than do unsymmetrical ones is still controversial. A novel determinant of illusory contour strength, parallelism, is proposed. Experiments are reported which indicate that illusory contours induced by 'blobs' which have boundaries that are nearby and parallel to the illusory contour are weaker than illusory contours induced by blobs that do not have this property. It is suggested that the display that has been most widely used by researchers to support their claims for a weakening of illusory contours with symmetrical inducers is weak primarily because of parallelism.     

Glucagon-like peptide I enhances the insulinotropic effect of glibenclamide in NIDDM patients and in the perfused rat pancreas

OBJECTIVE: To investigate the acute effects of glibenclamide and glucagon-like peptide I (GLP-I) and their combination in perfused isolated rat pancreas and in patients with secondary failure to sulfonylureas. RESEARCH DESIGN AND METHODS: Rat islets were perfused with 10 nmol/l GLP-I in combination with 2 mumol/l glibenclamide. In human experiments, GLP-I (0.75 pmol. kg-1.min-1) was given as a continuous infusion during 240 min, while glibenclamide (3.5 mg) was administered orally. Eight patients participated in the study (age 57.6 +/- 2.7 years, BMI 28.7 +/- 1.5 kg/m2, mean +/- SE). In all subjects, blood glucose was first normalized by insulin infusion administered by an artificial pancreas (Biostator). RESULTS: GLP-I increased the insulinotropic effect of glibenclamide fourfold in the perfused rat pancreas. In human experiments, treatment with GLP-I alone and in combination with glibenclamide significantly decreased basal glucose levels (5.1 +/- 0.4 and 4.5 +/- 0.1 vs. 6.0 +/- 0.3 mmol/l, P < 0.01), while with only glibenclamide, glucose concentrations remained unchanged. GLP-I markedly decreased total integrated glucose response to the meal (353 +/- 60 vs. 724 +/- 91 mmol.l-1. min-1, area under the curve [AUC] [-30-180 min], P < 0.02), whereas glibenclamide had no effect (598 +/- 101 mmol.l-1. min-1, AUC [-30-180 min], NS). The combined treatment further enhanced the glucose lowering effect of GLP-I (138 +/- 24 mmol. l-1.min, AUC [-30-180 min], P < 0.001). GLP-I, glibenclamide, and combined treat-stimulated meal-induced insulin release as reflected by insulinogenic indexes (control 1.44 +/- 0.4; GLP-I 6.3 +/- 1.6, P < 0.01; glibenclamide 6.8 +/- 2.1, P < 0.01; combination 20.7 +/- 5.0, P < 0.001). GLP-I inhibited basal but not postprandial glucagon responses. Using paracetamol as a marker for gastric emptying rate of the test meal, treatment with GLP-I decreased gastric emptying at 180 min by approximately 50% compared with the control subjects (P < 0.01). CONCLUSIONS: In acute experiments on overweight patients with NIDDM, GLP-I exerted a marked antidiabetogenic action on the basal and postprandial state. The peptide stimulated insulin, suppressed basal glucagon release, and prolonged gastric emptying. The glucose-lowering effect of GLP-I was further enhanced by glibenclamide. This action may be at least partially accounted for by a synergistic effect of these two compounds on insulin release. Glibenclamide per se enhanced postprandial but not basal insulin release and exerted a less pronounced antidiabetogenic effect compared with GLP-I.     

Convection in a concentric annulus with heat generating porous media and a permeable inner boundary

The effects of a permeable inner boundary on the maximum temperature and the convective flows were investigated numerically for a two-dimensional horizontal annulus containing a uniformly heat generating porous media. The time-dependent governing equations were nondimensionalized and put into an explicit finite difference numerical form. The finite difference equations were obtained from truncated Taylor series expansions using a central differencing scheme. Nondimensional temperatures and streamlines were obtained for heat generation rates ranging from 20 to 1,500 W/m³ corresponding to a range of modified Rayleigh numbers of 324 to 24,340 and for several combinations of isothermally heated wall conditions for annuli of radius ratio of 2. It was found that multi-cellular flows occur at the highest Rayleigh numbers investigated.     

The future of behavior therapy.

Predicts the future of behavior therapy, focusing on theoretical development, therapeutic techniques, and empirical research. The importance of cognitive and affective processes in behavior change will attract increasing attention. Already one of the most widely adopted approaches, behavior therapy will be used to treat an expanded range of psychiatric disorders and health problems. Research will focus on comparative outcome studies and provide probes for investigating the nature of specific disorders and the mechanisms of therapeutic change. (PsycINFO Database Record (c) 2010 APA, all rights reserved)