Abstract-In this paper, we present a stable, recursive algorithm for the Gabor filter that achieves-to within a multiplicative constant-the fastest possible implementation. For a signal consisting of samples, our implementation requires ( ) multiply-and-add (MADD) operations, that is, the number of computations per input sample is constant. Further, the complexity is independent of the values of and in the Gabor kernel, and the coefficients of the recursive equation have a simple, closed-form solution given and . Our implementation admits not only a "forward" Gabor filter but an inverse filter that is also ( ) complexity.

We have examined the hypothesis that diploid cells grown in vitro age, and propose that only proliferative potential and not life-span is telescoped. We suggest that explanted or transplanted diploid cells are driven to divide by the process of subculturing in vitro or in vivo and, in response to this pressure, also complete their differentiation and become refractory to further mitotic stimulation. We conclude that differentiation rather than "mortality" distinguishes diploid from transformed cells and that the former may not age in vitro, but are lost because culture methods are selective for cycling cells.

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Determination of the percentage of cells in clumps on a stained smear of human peripheral blood porvided a useful, accurate technique for measuring cell adhesiveness. Smears of human peripheral blood drawn with EDTA were prepared on a blood slide centrifuge, stained, and examined under a light microscope. Statistical analysis showed that the method resulted in a Poisson distribution of particles on the slide, where a particle was considered to be a simple cell, or two or more cells which appeared to be touching, Analysis of the distributions of erythrocytes and leukocytes showed that clumps were formed before the cells were deposited on the slide. When adhesiveness of erythrocytes or leukocytes was increased by incubation with antiserum to the corresponding cell type, the percentage of that cell type in clumps increased proportionately, Preliminary results using the method showed that normal human donors had similar to 1% of their erythrocytes and 1- 5% of their leukocytes in clumps. In chronic myelocytic leukemia, as many as 60% of the leukocytes were in clumps.

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