Time-domain analysis of auditory-nerve-fiber firing rates.

Time-domain analysis of firing-rate data from over 200 fibers from the auditory nerve of cat has been used to estimate the formants of the synthetic-syllable stimuli. Distinct groups of fibers are identified based on intervals between peaks in the fiber firing rates. The large extent of some of these groups--over an octave in terms of characteristic frequency--and the lack of short intervals in the longer-interval groups suggest that the behavior of the nonlinear cochlear filters for these signals is effectively wideband with steep high-frequency cutoffs. The measured intervals within each group are very similar, and correspond to the period of the formant that dominates the group's response. These intervals are used to estimate the dynamic speech formants. The overall formant estimates are better than those of the previous spectral analyses of the neural data, and the details of lower-formant dynamics are tracked more precisely. The direct temporal representation of the formant in contrasted with the diffuse spectral representation, the dependence of spectral peaks on nonformant parameters, and the distortion of the spectrum by rectification. It is concluded that a time-domain analysis of the responses to complex stimuli can be an important addition to frequency-domain analysis for neural data, cochlear models, and machine processing of speech.

Rehabilitation of the coronary patient.

52 out of 56 patients with myocardial infarction completed a 6-week rehabilitation programme. The exercise programme started on the second day of admission and continued during the patient's stay in hospital and for 6 weeks thereafter, with weekly attendances at the hospital. All the patients were assessed monthly by a coronary rehabilitation team. 77% of the patients went back to work in an average time of 9.5 weeks after onset of the infarction; 61% went to their original jobs and 16% had to modify their jobs. The approximate hospital cost per patient for the complete course was 11.33 pounds.

Uropygial gland alkane diol diesters in the Kn mutation of the domestic chicken.

Uropygial glands from chickens which are known to have the Kn gene secrete qualitatively the same types of alkane diol diesters as the normal domestic chicken. However, there are many significant differences in the mole percent of individual fatty acids and diols within the diester between the two genetic types of chickens. In general, the mutant chickens have lesser amounts of the shorter chain fatty acids and diols and greater amounts of the longer chain fatty acids and diols. There is also a gene dosage effect with two mutant genes having a greater effect in many cases than a single mutant gene.

Laser tuners using circular piezoelectric benders.

This paper presents the results of an experimental evaluation of a new type of piezoelectric ceramic device designed for use as a laser mirror tuner. Thin plates made from various materials were assembled into a circular bimorph configuration and tested for linearity of movement, maximum travel, and resonant frequency for varying conditions of clamping torque and mirror loading values. Most of the devices tested could accept mirror diameters up to approximately 1.3 cm and maintain a resonant frequency above 2 KHz. Typical mirror translation without measurable tilt was +/-20 microm or greater for applied voltages of less than +/-300 V.