Marvin B. Shapiro

DEVELOPMENT OF THE ISOLATION PEEP IN LABORATORY-BRED SQUIRREL MONKEYS

The development of Isolation Peeps (IPs) was studied in seven laboratory-reared squirrel monkeys (Saimiri sciureus) over the age range of one day to two years. IPs were identified by specified criteria from the wide range of vocalizations recorded and analysed by descriptive and statistical methods. Despite the presence of substantial maturational changes in IPs, the data reveal individuality or vocal signature at all ages tested. Furthermore, the animals had developed by the end of the study unique and stable IPs comparable to those recorded previously from wild-caught adults.

The choice of reference points in best-match file searching

Improvements to the exhaustive search method of best-match file searching have previously been achieved by doing a preprocessing step involving the calculation of distances from a reference point. This paper discusses the proper choice of reference points and extends the previous algorithm to use more than one reference point. It is shown that reference points should be located outside of data clusters. The results of computer simulations are presented which show that large improvements can be achieved by the proper choice and location of multiple reference points.

An Algorithm for Reconstructing Protein and RNA Sequences

An algorithm for deriving the primary sequence of a protein or RNA is presented. The data is in the form of short sequences of letters which must be fitted together to form the unknown complete sequence. A computer program for carrying out the steps is described, with an example. It is shown that the algorithm cannot make an error and empirical results are given which illustrate the successful use of the algorithm in reconstructing complete sequences known to be solvable.

A new technique for measuring muscle fiber conduction velocities in full interference patterns

The motor unit potential shape, mainly its duration and frequency spectra, and the EMG IP crispiness and its frequency spectra are affected by the muscle fiber conduction velocities (MFCVs). Present techniques are somewhat deficient in that they are not adaptable to measure MFCVs continuously and intramuscularly in the presence of interference patterns, and to do so without interfering with the ongoing muscular activity. In this study a cross-correlation with averaging correlograms technique is presented. An EMG needle electrode, with two recording surfaces 1 cm apart, continuously record two channels of EMG activity which is analog-to-digital converted. Contiguous segments of the signals are cross-correlated, the evolved correlograms are averaged together, averaging-out the time-unlocked noise, and averaging-in a peak that represent the average time it takes the EMG signal to propagate from one recording surface to the other. From the distance between these two recording surfaces and the above calculated propagation time the MFCVs can be computed and monitored intramuscularly either in weak or in strong, in isometric or isotonic contractions. But for the fact that a needle is introduced, there is no interference with the muscle electrical activity. It is expected that this technique may add to EMG diagnosis of neuromuscular disorders, will be used to monitor muscular fatigue and applied in normalizing EMG spectra, conditioning them for a better use in diagnostic electromyography.

Spectral analysis of the EEG in hepatic encephalopathy treated with levodopa

Abstract A marked increase in the low frequencies is the hallmark of the EEG changes in hepatic encephalopathy (HE). These changes are the best known correlates to the clinical state. In many cases with HE, dramatic clinical and electroencephalographic improvement were observed in response to levodopa treatment. In this study frequency analysis of EEG records that had been taken in acute HE was performed and EEG power values before treatment were compared to power values during lactulose-neomycin-levodopa treatment, when clinical and EEG improvement occured. Nine cases were recorded both before and during treatment, six were recorded only before and one case only during treatment. The power-spectral calculations were performed on long time segments with overlaying and averaging, and a special data window (Blackman-Harris 4 sample window) was used, in order to increase resolution. As expected it was found that there was a marked and significant decrease in the low-frequencies power in response to treatment, which also correlated well with the clinical improvement. It was found, contrary to the impression one may get from the clinical EEG records, that the alpha and beta frequencies power was not affected either by the HE dysmetabolic state, or by the treatment and did not correlate at all with the clinical improvement. These findings suggest that the slow-wave generating processes are in fact activated by the hepatic encephalopathy dysmetabolic states, and that this phenomenon may not be due to ‘slowing’ of the alpha and the beta generating processes. These last processes did not respond to the dysmetabolic state, nor did they respond to the treatment with high doses of levodopa. This might also suggest that the alpha and beta generating processes are neither dopaminergic nor serotoninergic. In addition it seems that the slow-wave generating processes are levodopa responders. This last conclusion is somewhat weaker than the others, as all our cases were treated with lactulose and neomycin as well as levodopa, and one may attribute the reduction of slow waves to the metabolic improvement and not to the direct effect of levodopa.

Reconstruction of protein and nucleic acid sequences: IV. The algebra of free monoids and the fragmentation stratagem

The problem of determining the sequence of a biopolymer from its fragments is stated in mathematical terms. Using concrete properties of a free monoid, certain general classes of biopolymers are shown to be insolvable from fragment data produced by complete digestion where enzymes specific for any possible combination of chemical bonds are employed.

A Note on Lee and Schachter's Algorithm for Delaunay Triangulation

Lee and Schachter have presented an algorithm for the Delaunay triangulation of a set of points whose convex hull is a rectangular region. An addendum to that algorithm is presented which gives the Delaunay triangulation of a set of points with an arbitrary convex hull. Timing results are also given.