Psychology and mental health: An enduring partnership.

Discusses the relationship between psychology and the National Institute of Mental Health's (NIMH's) funding of research in the behavioral sciences and the diagnosis, treatment, and prevention of mental illness. It is pointed out that, despite the fears of biological reductionism, the NIMH is determined to maintain a balanced program across the broad spectrum of its efforts. The funding of current research efforts in a variety of areas is outlined. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the numerical solution of the stokes equations using the finite element method

A numerical solution of the stationary Stokes equations is considered based on the work of Crouzeix and Raviart [1]. The finite element method is used to discretize the partial differential equations, and a direct discretization of the velocity field and pressure is given which is applicable in both two and three dimensions. It is shown that not every arbitrary element can be used, and a condition is given to check whether or not an element is admissible. The system of linear equations is solved using the method of Powell and Hestenes for constrained optimization (see [2]).     

Activity of units in the hippocampal circuit of the rat during differential classical conditioning.

Recorded unit activity from electrodes chronically implanted in various hippocampal areas of 17 male Holtzman albino rats during differential classical conditioning. 1 auditory frequency signaled food, another signaled electric shock. Unit activity was recorded during 1 sec. prior to applications of the tones and during the 1-sec CS-UCS intervals. Response latencies and changes in frequency of unit activity throughout the recording period were determined. Units in the dentate had longer latencies than units in the hippocampus, some of which responded within 16 msec. of the application of the CS. The dentate was the only area to show excitation in response to a positive signal and inhibition in response to a negative signal. (18 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Appraisal of the self-schema construct in cognitive models of depression.

Discusses the role of self-schemata in cognitive models of depression and evaluates the empirical support for this notion according to criteria consonant with this construct's usage in cognitive psychology and social cognition. Whereas the concept of a negative self-schema was initially proposed as a distal cognitive diathesis to depressive disorder, measurement problems have hindered a meaningful test of this construct's predictive capacity. Furthermore, conceptual and design-related confounds in extant depressive-schema studies prevent the demonstration of schematic processing independent of the effects of depressed mood on the dependent variables used. It is argued that reconceptualizing self-schema in cognitive-structural terms may help address and resolve some of these current problems. For example, methods used to assess more general knowledge structures, such as semantic networks, might be profitably used to verify whether information about the self is similarly organized. This can then begin the process of specifying the exact nature of the information thought to be stored within this structure and allow researchers to move beyond a simple dichotomy of positive and negative elements to models that better reflect the complexity of self-construal. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sensation seeking and anxiety: Assessment of responses to specific stimulus situations.

Investigated findings of research which indicate the presence of a personality dimension identified as sensation seeking. Sensation seekers have been characterized as seeking a level of optimal stimulation, evidenced in thrill-oriented types of behavior. This study with 127 undergraduates sought to determine if there was a relationship between sensation seeking and anxiety level. It was expected that sensation seeking would not be accompanied by an increase in tension. Results tend to confirm that expectation, thus providing some degree of additional validity to the concept of sensation seeking as a specific personality dimension. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An analytical examination of mathematical models for the rainfall rate distribution function

A large, digitized data base is employed in a detailed examination of the mathematical form of the point rainfall-rate distribution function. The optimum form is found to depend on both the data sampling rate and the rain rate limits considered. In general, the lognormal function appears to provide a very good approximation to the distribution. It is found, however, that a better fit is provided by piecewise power-law approximations to different portions of the distribution. As the sampling interval is reduced to the ultimate limit imposed by the tipping bucket itself, a single power relationship is found to provide the best fit over the range of rainfall rates from several mm/h to the observed upper limit.     

Convergence of sensory input on units in the hippocampal system of the rat.

Recorded unit responses to auditory and visual stimuli from chronically implanted electrodes in the limbic system of 22 albino male Holtzman rats. The stimuli were presented first in a random order and later in a classical sensory conditioning paradigm in which a flash of light followed a tone. Short latency unit responses to both light and tone were found in the medial septum and the cingulate cortex. The conditioning paradigm did not cause significant changes in the firing rates of nonresponding units and did not significantly change existing responses. Only small transient changes were noticed in CA1 hippocampal units. It is concluded that sensory responses could be detected in the hippocampus and its afferents, but a classical sensory paradigm is not an efficient way to enhance hippocampal responsiveness to neutral stimuli. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Thermodynamic evaluation of chemically vapour- deposited Si3N4 films prepared by nitradation of dichlorosilane

The chemical vapour deposition (CVD) of Si₃N₄ layers based on the nitridation of dichlorosilane (SiH₂Cl₂) is evaluated thermodynamically. A study of the Gibbs free energy as a function of the temperature shows that Si₃N₄ deposition from the SiH₂Cl₂-NH₃ system is favoured to a greater extent than that from the SiH₂Cl₂-N₂ system. A similar study of the CVD of silicon oxynitride layers by the concomitant oxidation (with O₂, N₂O or CO₂) and nitridation (with NH₃) of SiH₂Cl₂ shows that the reactions of SiH₂Cl₂ with O₂ and N₂O are thermodynamically more favoured than its reaction with NH₃. The reverse effect is obtained when CO₂ is used as the oxidizing agent. A thermodynamic analysis of the SiH₂Cl₂-NH₃ system was made by solving numerically a set of equations involving the partial pressure of each species and the equilibrium constants at the temperature under consideration. From these calculations we can predict the gas phase composition, the amount of deposit expected and the efficiency of the deposition under various experimental conditions.