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Ten Real-Time Active Control Points (RTACP) across Canada continuously monitor all GPS satellites in view and generate wide area GPS corrections with an update rate of 2 s. Dual frequency high precision geodetic GPS receivers using free running atomic frequency standards (masers, Cs and Rb) provide pseudorange and phase measurements at 1 s intervals. Ionosphere-free, carrier-phase-filtered pseudorange data are combined with rapid GPS satellite orbit predictions and RTACP coordinates in a least-squares adjustment to determine satellite and station clock offsets with respect to a virtual reference clock (VRC). The VRC is maintained us a weighted mean of RTACP long-term clock models. The VRC is related to the mean GPS system time using a long-term linear clock model with correlation time of a few days and it is traceable to UTC (TVRC). This approach mitigates the effects of instabilities of individual RTACP clocks, eliminates clock discontinuities, and provides VRC stability better than 10(-14) for time intervals greater than 1 day. The system provides continuous RTACP clock synchronization with RMS residuals in the range of 0.1-0.5 ns and real-time GPS satellite clock corrections with RMS residuals in the range of 0.3-0.8 ns. The quality of the real-time results are presented and discussed., See also ADA415578. Presented at the Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting (30th) held in Reston, VA on 1-3 Dec 1998. Published in the Annual Precise Time and Time Interval Systems and Applications Meeting Proceedings, p187-200, Dec 1998.

Canadian plans for precise time and time interval services are examined in the light of GPS capabilities developed for geodesy. We present our experience in establishing and operating a geodetic type GPS station in a time laboratory setting, and show sub-nanosecond residuals for time transfer between geodetic sites. We present our approach to establishing realistic standard uncertainties for short-term frequency calibration services over time intervals of hours, and for longer-term frequency dissemination at better than the 10(-15) level of accuracy., Presented at the Annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting (26th) held in Reston, VA on 6-8 Dec 1994. Published in the Annual Precise Time and Time Interval Applications and Planning Meeting Proceedings, p141-152, Dec 1994.

Single unit responses to tone pips (200 ms duration) or clicks were studied in the inferior colliculus of anaesthetized guinea-pigs. In all, 360 neurons were investigated. The tonotopic organization of neurons in the inferior colliculus and shapes of the threshold tuning curves were comparable with the data known in other laboratory animals. The majority of neurons (83.5 percent) displayed a tonic response to tonal stimuli, the remaining 16.5 percent of units responded with a typical "on" reaction at the beginning of the stimulus. The spike-intensity functions of 50 percent of neurons were of the non-monotonic type, the saturation of response was observed usually at 20-30 dB above the threshold. Monaural stimulation of the contralateral ear evoked an excitatory response in all cases; ipsilateral ear stimulation exerted an excitatory response in 61.8 percent of neurons, an inhibitory response in 17.6 percent of neurons and for 20.6 percent of units ipsilateral ear stimulation was uneffective. The occurrence of neuronal responses to stimuli with an interaural time delay or intensity differences was also investigated.