Robust monomer-distribution biosignatures in evolving digital biota

Because organisms synthesize component molecules at rates that reflect those molecules' adaptive utility, we expect a population of biota to leave a distinctive chemical signature on their environment that is anomalous given the local (abiotic) chemistry. We observe the same effect in the distribution of computer instructions used by an evolving population of digital organisms, and characterize the robustness of the evolved signature with respect to a number of different changes in the system's physics. The observed instruction abundance anomaly has features that are consistent over a large number of evolutionary trials and alterations in system parameters, which makes it a candidate for a non-Earth-centric life-diagnosticComment: 22 pages, 4 figures, 1 table. Supplementary Material available from C

The discoveries of uranium 237 and symmetric fission — From the archival papers of Nishina and Kimura

Shortly before the Second World War time, Nishina reported on a series of prominent nuclear physical and radiochemical studies in collaboration with Kimura. They artificially produced 231Th, a member of the natural actinium series of nuclides, by bombarding thorium with fast neutrons. This resulted in the discovery of 237U, a new isotope of uranium, by bombarding uranium with fast neutrons, and confirmed that 237U disintegrates into element 93 with a mass number of 237. They also identified the isotopes of several middle-weighted elements produced by the symmetric fission of uranium. In this review article, the highlights of their work are briefly summarized along with some explanatory commentaries

LIQUID THERMAL DIFFUSION

A revised and expanded version of NNES-DC-1. The liquid thermal diffusion method for the separation of isotopes is described. The discussion includes the experimental aspects of the method, description of equipment, and the theoretical aspects of the process as applied to the design, development, and performance criteria. A short history of the liquid thermal diffusion method from 1940 to 1945 is preserted along; with a survey of relevant literature prior to 1940. The remainder of the report is concerned with theoretical aspects. (J.R.D.

Extraction, analysis and interpretation of intracrystalline amino acids from fossils

A new protocol for the extraction and analysis of intracrystalline macromolecules has been developed that allows the rapid determination of the amino-acid composition of fossils. The technique utilizes decalcification with 2 M HCI, characterization of the soluble fraction of the biomolecules by automated amino-acid analysis, and differentiation using multivariate statistics. Compared to other methods, this technique allows sampling of indigenous degraded proteins in addition to the preserved remains of peptides, leading to the recovery of data from more reliable indigenous sources. Although the extraction method is demonstrated using fossil samples to demonstrate gross phylogenetic differences, there is much potential to use these biomolecules for a wide range of application