Effects of inhibitory amino acids on the frequency components in sympathetic nerve discharge

The effects of the GABA antagonist picrotoxin and the glycine antagonist strychnine on the frequency components in sympathetic inferior cardiac nerve activity were observed. Picrotoxin (0.03-1.0 mg/kg) increased power in the 10-Hz component of sympathetic activity and produced a dramatic shift in the rhythm to higher frequencies. Only small changes were noted in the 2- to 6-Hz component. Strychnine produced a small generalized increase in power in both frequency bands in sympathetic activity. These data suggest that GABA may play an important role in the generation and maintenance of the 10-Hz rhythm in sympathetic activity while glycine likely inhibits activity at a site of convergence of the two rhythms in sympathetic activity.     

Inferring category characteristics from sample characteristics: Inductive reasoning and social projection.

Inductive reasoning involves generalization from sample observations to categories. This research examined the conditions under which generalizations go beyond the boundaries of the sampled categories. In Experiment 1, participants sampled colored chips from urns. When categorization was not salient, participants revised their estimates of the probability of a particular color even in urns they had not sampled. As categorization became more salient, generalization became limited to the sampled urn. In Experiment 2 the salience of categorization in social induction was varied. When social categorization was not salient, participants projected their own responses to test items to members of a laboratory group even when they themselves did to belong to this group. When salience increased, projection decreased among nonmembers but not among members. In Experiment 3 these results were replicated in a field setting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Bone size and mechanics at the femoral diaphysis across age and sex

The reasons for the increase in fracture rates with age are not fully understood. It is known that there is a decrease in bone mass with a presumed loss of strength. This decrease may possibly be compensated for by changes in cross-sectional geometry. Previous studies, which have been limited by lack of information on subjects' heights and weights, were not able to resolve this issue. In this study, measurements of cross-sectional geometry (area and second moments of area) from 107 specimens of human femoral diaphysis from subjects aged 21-92 years were analysed. Mathematical models of the variation in bone geometry with age were developed. These models included the effects of sex, height and weight. Values of parameters from these models were then used in a biomechanical analysis of the static stresses at the mid-shaft of the femur. Results indicate that although there was a reduction in cortical area in old age, bone tissue was redistributed so that neither bending stresses in the coronal plane nor torsional stresses were higher in old age than in young adulthood. An additional finding was that at any age women had smaller bones, less cortical bone area and higher bone stresses than men. This finding may have some bearing on the higher fracture incidence seen in older women.     

Functional subcaste discrimination (foragers and brood-tenders) in the antCamponotus vagus scop.: polymorphism of cuticular hydrocarbon patterns

In the antCamponotus vagus, when selected foragers that had been earlier removed from the foraging arena and brood-tenders that had been earlier removed from the nest were placed together in a foraging arena, most of the brood-tenders and only a few of the selected foragers were carried back to the nest by nonselected foragers. We hypothesize that cuticular hydrocarbons serve as a cue that allows foragers to discriminate between members of their own subcaste and brood-tenders. It has been established that the proportions of certain hydrocarbons, which are the same regardless of the colony studied, vary from one worker subcaste to another and thus constitute a specific chemical signature. These hydrocarbons belong to a wide range of chemical families (alkanes, monomethylalkanes, and dimethylalkanes). The greatest differences between the two subcastes were observed on the thorax of workers. Principal component analyses performed on the hydrocarbons (or hydrocarbon combinations) corresponding to the 45 main peaks in the cuticular profiles of the head and thorax of brood-tenders and foragers of several colonies show that there exist quantitative differences between the various signatures that characterize the colony, the worker subcastes, and the various body parts within the same species, which can be classified in a hierarchy where the differences between worker subcastes are less pronounced than those between body parts or between colonies.     

Analysis and simulation of new approximation equations for boundary-layer flow on curved surfaces

An accurate and computationally efficent simulation of viscous flow fields exhibiting streamline curvature effects is important for the basic understanding and optimal design of a variety of mechanical systems. Examples include flow part airfoils, marine crafts, and automobiles or flow in diffusors and curved ducts. In this paper a new set of second-order boundary-layer equations is derived for steady incompressible two-dimensional or axisymmetric flow in regions where the streamlines stay approximately parallel to the curved surface. The performances of the new approximation equations and commonly used second-order boundary-layer equations are evaluated in two case studies. First, in a well-defined computer experiment, results from the two different sets of approximation equations are compared with a solution of the full Navier—Stokes equations for laminar flow past a representative body with longitudinal curvature. Then, turbulent flow versions of the new and traditionally used second-order boundary-layer equations are compared with experimental data sets for a representative axisymmetric body with strong longitudinal and transverse curvatures.     

A State Language for the Sequencing in a Hybrid Electric Vehicle

The application of a state language to the real-time control of a hybrid electric vehicle is explained. The state language has been developed both as a specification aid to the system designer and as a means for the programmer to produce microcomputer software. A translator program, which was developed on a VAX minicomputer, preprocesses the state language into a software module to be compiled by the standard Intel PL/M 86 compiler.     

Application of liquid-metal MHD generators to the LMFBR

The feasibility of coupling two-phase liquid-metal magnetohydrodynamic generators (LMMHD) to liquid-metal fast breeder reactors (LMFBR) is examined. Important constraints on the LMFBR-LMMHD system that were not accounted for in earlier studies have been included.A LMMHD cycle coupled to a gas turbine cycle yielded an overall cycle efficiency of 35.2% which is less than the efficiency of 36.2% when the gas turbine cycle is utilized by itself. However, a LMMHD cycle coupled to a steam cycle shows a slight advantage (38.9–39.8% overall cycle efficiencies for generator efficiencies varying from 80 to 90%) over the conventional steam cycle (38.5% efficiency).