Gender, motivation, and coping in the evaluation of leadership effectiveness.

Examined the effects of gender, coping, and motivational orientation in evaluating individual leadership. Ss were 17 female and 31 male graduate students in an intensive leadership development program at a leading business school. The Shanan Sentence Completion Technique, Jackson's Personality Research Form, and Raven's Advanced Progressive Matrices were used to predict peer ratings of leadership at the end of the 9-mo program. The data reveal significant gender differences on the measures of motivation, with men showing higher levels of agentic instrumental tendencies and women exhibiting higher levels of communal-social qualities. These qualities, in turn were differentially correlated with evaluations of leadership. Women exhibiting strong agentic characteristics were negatively perceived as leaders. There was no relationship between agentic or communal qualities and evaluations of leadership received by male leaders. Finally, individuals with active coping tendencies were evaluated as more effective leaders for both genders. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Local linear perceptrons for classification

A structure composed of local linear perceptrons for approximating global class discriminants is investigated. Such local linear models may be combined in a cooperative or competitive way. In the cooperative model, a weighted sum of the outputs of the local perceptrons is computed where the weight is a function of the distance between the input and the position of the local perceptron. In the competitive model, the cost function dictates a mixture model where only one of the local perceptrons give output. Learning of the local models' positions and the linear mappings they implement are coupled and both supervised. We show that this is preferable to the uncoupled case where the positions are trained in an unsupervised manner before the separate, supervised training of mappings. We use goodness criteria based on the cross-entropy and give learning equations for both the cooperative and competitive cases. The coupled and uncoupled versions of cooperative and competitive approaches are compared among themselves and with multilayer perceptrons of sigmoidal hidden units and radial basis functions (RBFs) of Gaussian units on the application of recognition of handwritten digits. The criteria of comparison are the generalization accuracy, learning time, and the number of free parameters. We conclude that even on such a high-dimensional problem, such local models are promising. They generalize much better than RBF's and use much less memory. When compared with multilayer perceptrons, we note that local models learn much faster and generalize as well and sometimes better with comparable number of parameters.     

Analysis of cylindrical-to-plane-wave conversion by volume holograms

The properties of volume holograms produced by the interference of a cylindrical and a plane wave are studied. By analogy with Kogelnik's treatment of the plane wave, coupled differential equations are derived, and solved, for a transmission hologram illuminated by a cylindrical wave.     

Production of highly-sinterable rare-earth oxide powders by controlled humidity dewatering of precursors

The sintering behavior of rare-earth oxide powders produced from reverse strike hydroxide, oxalate and carbonate precursors was studied. The influences of controlled humidity dewatering of precursors on powder morphology and sintering behavior were extensively studied, and were compared with those produced by oven drying or dewatering by using organic washes (ATA method). Significant differences in behavior were observed for hydroxide- and carbonate-derived powders dewatered in different ways; oxalate-derived powders showed little behavioral dependence on dewatering method. In general, controlled humidity dewatering proved effective in leading to highly-sinterable powders from any of the three precursors investigated, ATA treatment was effective for hydroxide and oxalate precursors, and oven drying generally led to good sinterability only for oxalate-derived powders. Compaction behavior and surface area of the powders were also determined and attempts were made to correlate these characteristics with sintering behavior.     

Apparatus and instruments for the laboratory study of multi–anchored flexible retaining walls

Details are presented of the apparatus and instruments developed for the study of the behaviour of laboratory scale multi–anchored flexible retaining walls. The instruments enabled measurements to be made of the earth pressures on and the bending moments in very flexible walls. The shearing and thrust forces at wall base level and the individual anchor wire loads, as well as the movements of the wall and the retained sand, were also monitored throughout a simulated wall construction sequence.     

Left colon gangrene after acute inferior mesenteric artery occlusion

We report here an experience with five patients, aged 58 to 70, suffering gangrene of the left colon after spontaneous inferior mesenteric artery occlusion. All cases were the result of arteriosclerosis; in two, small aortic aneurysms were present and might have been responsible for emboli to the inferior mesenteric artery. The dead bowel was resected in all patients; three patients survived. No primary anastomoses were done and they are not recommended. Because ligation of the patent inferior mesenteric artery has been done so often without ill effects during aortic surgery, the collateral circulation to the left colon can be considered excellent. Gangrene is therefore rare and requires major interference with collateral circulation by emboli or arteriosclerotic occlusion. The clinical symptoms and signs may be confusing.     

Novel injectable urethral bulking agents for the treatment of urinary incontinence

Stress urinary incontinence is a highly prevalent disorder resulting from weak urethral closure mechanisms. Endoscopic injection of a urethral bulking agent (UBA) under the urethral mucosa increases coaptation, which improves continence. Collagen is an efficient agent, although its effects are limited in time. Other materials still suffer either from a short-lasting effect or migration in distant organs. We evaluated here novel UBAs using an ex vivo model, with respect to criteria of ease of injection, ability to form a high and stable tissue bulking, implant elasticity and tissue reaction. One approach involves solutions of polymers in water-miscible organic solvents that precipitates in situ. In this manner, high and stable bulks were routinely obtained using various commercial polymers. Selected solvents reduced the tissue reaction to the implant. Microsphere suspensions in hydrogels also proved to be efficient UBA, although less stable bulks were obtained. Thermosetting chitosan hydrogels showed promising results with respect to bulk stability and isoelasticity with surrounding tissues. Different strategies have thus been compared and optimised ex vivo. Further experiments are required to compare the ability of these materials to induce a sustained in vivo bulking effect.