Note on arithmetic codes and arithmetic distance

Cyclic arithmetic codes and their distance properties with demonstration of modular arithmetic weight invariance to code word cyclic shift

Water Balance of a Small Lake in a Permafrost Region

The work upon which this report is based was supported in part by funds (Project A-031-ALAS) provided by the United States Department of the Interior, Office of Water Resources Research, as authorized under the Water Resources Act of 1964, as amended

Flexible high speed codec

The project's objective is to develop an advanced high speed coding technology that provides substantial coding gains with limited bandwidth expansion for several common modulation types. The resulting technique is applicable to several continuous and burst communication environments. Decoding provides a significant gain with hard decisions alone and can utilize soft decision information when available from the demodulator to increase the coding gain. The hard decision codec will be implemented using a single application specific integrated circuit (ASIC) chip. It will be capable of coding and decoding as well as some formatting and synchronization functions at data rates up to 300 megabits per second (Mb/s). Code rate is a function of the block length and can vary from 7/8 to 15/16. Length of coded bursts can be any multiple of 32 that is greater than or equal to 256 bits. Coding may be switched in or out on a burst by burst basis with no change in the throughput delay. Reliability information in the form of 3-bit (8-level) soft decisions, can be exploited using applique circuitry around the hard decision codec. This applique circuitry will be discrete logic in the present contract. However, ease of transition to LSI is one of the design guidelines. Discussed here is the selected coding technique. Its application to some communication systems is described. Performance with 4, 8, and 16-ary Phase Shift Keying (PSK) modulation is also presented

Remnants of an ancient metabolism without phosphate

Phosphate is essential for all living systems, serving as a building block of genetic and metabolic machinery. However, it is unclear how phosphate could have assumed these central roles on primordial Earth, given its poor geochemical accessibility. We used systems biology approaches to explore the alternative hypothesis that a protometabolism could have emerged prior to the incorporation of phosphate. Surprisingly, we identified a cryptic phosphate-independent core metabolism producible from simple prebiotic compounds. This network is predicted to support the biosynthesis of a broad category of key biomolecules. Its enrichment for enzymes utilizing iron-sulfur clusters, and the fact that thermodynamic bottlenecks are more readily overcome by thioester rather than phosphate couplings, suggest that this network may constitute a "metabolic fossil" of an early phosphate-free nonenzymatic biochemistry. Our results corroborate and expand previous proposals that a putative thioester-based metabolism could have predated the incorporation of phosphate and an RNA-based genetic system. PAPERCLIP

Calibration of a Liquid Scintillator with Geiger-Mueller Counters

It was the purpose of this experiment to examine the difference in the density determinations and, since the Geiger tube threshold is much lower, to calibrate the liquid scintillator so that it is capable to determining the absolute particle density with greater accuracy

Fire Retardant Treated Lumber

THE STORY of fire retardant lumber is as old as man. Since the day that he learned to make a fire, man has endeavored to learn how to control it. Wood is one of man\u27s oldest building materials. History has recorded the uses that he has made of wood, as well as the conflagrations that have caused him to investigate the possibilities of reducing the combustibility of wood

Ted Stein: Recollections of a Friend and Colleague

Measuring the impact of Ted Stein\u27s tragic death presents a difficult task, because his contributions to colleagues and friends were so large and various. Ted possessed a multitude of admirable qualities and unlimited potential for further contributions to the development of international legal theory, to the Law School, to the community, and to his family