Precision constrained stochastic resonance in a feedforward neural network

Stochastic resonance (SR) is a phenomenon in which the response of a nonlinear system to a subthreshold information-bearing signal is optimized by the presence of noise. By considering a nonlinear system (network of leaky integrate-and-fire (LIF) neurons) that captures the functional dynamics of neuronal firing, we demonstrate that sensory neurons could, in principle harness SR to optimize the detection and transmission of weak stimuli. We have previously characterized this effect by use of signal-to-noise ratio (SNR). Here in addition to SNR, we apply an entropy-based measure (Fisher information) and compare the two measures of quantifying SR. We also discuss the performance of these two SR measures in a full precision floating point model simulated in Java and in a precision limited integer model simulated on a field programmable gate array (FPGA). We report in this study that stochastic resonance which is mainly associated with floating point implementations is possible in both a single LIF neuron and a network of LIF neurons implemented on lower resolution integer based digital hardware. We also report that such a network can improve the SNR and Fisher information of the output over a single LIF neuron.     

The practice of recruitment and selection of student nurses at a college of nursing in Kwazulu/Natal

This is a report on a study that was conducted to obtain the nurse-educators and student nurses' views regarding recruitment and selection techniques used at a particular college of nursing to attract school leavers for nurse training. A survey was conducted on a sample of forty student nurses at their third and fourth year level of training as well as twenty nurse-educators. Analysis of findings revealed that a substantial number of nurse-educators were not well versed with the selection policy followed at the college. Furthermore, it showed that recruitment was not done and that the selection criteria used were not relevant to the nature and scope of the curriculum of the four year comprehensive diploma course.