– Bacteria (e.g. E. Coli) are very sensitive to certain chemoattractants (e.g. asparate) which they themselves produce. This leads to chemical instabilities in a uniform population. We discuss here the different case of a single bacterium, following the general scheme of Brenner, Levitov and Budrene. We show that in one and two dimensions (in a capillary or in a thin film) the bacterium can bec...

HE apparent mutation rate depends upon a number of contingencies: the Tprimary error rate, the probability o€ repair, error avoidance by the apparatus of DNA replication, and the probability of detection. The probability of detection of those base pair substitutions which produce an amino acid substitution appears to be highly variable, and presumably reflects the sensitivity of polypeptide fun...

the absence of mental changes and family history. Secondly, the meningeal reaction was not present. Thirdly, the lesion in the corpus stiatum was strictly confined to the caudate nuclei with normal lentiform nuclei. The thalamus showed no pathological abnormality. Fourthly, it is stated by various authors that the lesion in the corpus striatum affects principally the small ganglion cells with s...

Analytic bond-order potentials ~BOP’s! are derived for the s and p bond orders by approximating the many-atom expansion for the bond order within the two-center, orthogonal tight-binding ~TB! model. The analytic expression, BOP4, is obtained by retaining terms to four levels in the continued fractions for the appropriate Green’s functions and describes the s bonds in the dimer C2 , the tetrahed...

While for 25 years it had been clear the DNA contained the basic genetic information, by 1960 it was still not at all clear how that information was expressed. How did a difference in the sequence of nucleotide bases translate into the differences between an elephant and a flea? The boundaries of the problem had been roughed out even before the era of Watson-Crick DNA. It was shown that all of ...