The transmission of digital signals through random, time-variant, dispersive channels with application to chaff scatter

This paper is a report on the characterization and modeling of a specific dispersive communication channel, a chaff scatter channel. Theoretical and experimental results are given. The basic modeling of the chaff scatter channel as a linear, time-variant, random-parameter filter is given and its salient properties developed. Based on this model, a theoretical analysis of a continuous-phase binary FSK communications system operating over the chaff scatter channel is given. Experimental results obtained in the use of this system on an actual chaff scatter channel are then presented and compared with the theoretical results.     

Transplacental and immediate effect of ortho-aminoazotoluol on organ cultures of embryonal mouse liver

A study was made of the transplacental and direct action of orthoaminoazotoluol (OAAT) in the organ cultures of the embryonic liver of mice of a highly hepatomic CBA line. In direct action in vitro OAAT caused a marked reduction of survival of the organ cultures of the embryonic liver in comparison with control. In the transplacental action of OAAT the toxic effect was replaced at the last periods of cultivation by the growth stimulating one; the percentage of live experimental cultures increased by 30 in comparison with control.     

Lithium in Europe (summary)

Lithium was discovered 160 years ago by Arfvedson, a Swedish geologist. About 50 years ago, lithium carbonate was first produced in industrial quantities by Metallgesellschaft AG in Germany, using a mica-type lithium mineral, the zinnwaldite, as starting material.Europe has no large deposit of spodumene, petalite or amblygonite, which could serve as a base for industrial production of lithium compounds. Only lepidolite occurs in quantities big enough to envisage such a production if the market justifies the higher cost involved in using lepidolite instead of spodumene as basic raw material. This may very well be the case for the feedstock of a nuclear fusion-energy plant.For the time being, nearly all lithium raw material, especially lithium carbonate and the ores for direct application, are imported from America, Russia and Africa.At the present time, Metallgesellschaft is the only industrial producer of lithium compounds in Europe. Other producers, like Rhône Poulenc in France, Montecatini in Italy and Associated Lead in England, have abandoned their lithium activities due to unfavourable economic conditions.Metallgesellschaft produces the whole range of lithium compounds: lithium hydroxide, all types of lithium salts, lithium metal, butyl lithium and the lithium hydrides (especially lithium aluminum hydride). The plant capacity is big enough to satisfy any possible demand.The uses for lithium ores and chemicals are, with a few modifications, the same as in the United States. About 15–20,000 tons of lithium minerals are used in the ceramic, enamelling and glass industry, in many cases in order to replace fluorspar.The most interesting new application of lithium compounds is the use of lithium carbonate in the aluminum industry, which allows either up to 10% higher production and/or cost and energy savings and reduction of fluorine emission. If no new applications (e.g. the lithium battery) develop, growth in the lithium market in Europe is expected to come mainly from the aluminum industry, which could double present consumption of about 2 million lb of lithium carbonate within the next 5–10 years. All other applications, such as production of lithium hydroxide for lubricating greases or lithium chloride for welding fluxes, are quite stable or only slowly increasing. Some uses are shrinking, e.g. the use of lithium bromide for air-conditioning equipment. Also, more highly sophisticated compounds, such as butyl lithium or lithium aluminum hydride, show only very modest growth rates.Europe's total lithium-compound requirements expressed as lithium carbonate equivalents are at present on the order of 7 million lb.The lithium industry can cope with an increase in demand, not only for lithium carbonate but also for the other compounds. No spectacular development in lithium prices is anticipated.     

Improving the diagnostic reliability of rapidly fluctuating plasma hormone levels by optimized multiple-sampling techniques

When plasma hormone levels undergo rapid and large oscillations, as in the case of testosterone, FSH, and LH, a single random sample is likely to yield a result within +/-20% of the true mean value only 68%, 54%, and 30% of the time, respectively. Multiple sampling increases reliability, and computer analysis demonstrates that three equally-spaced samples taken at 6 to 18 min intervals provide the optimum schedule, given certain practical considerations. Pooling of the three plasma samples prior to radioimmunoassay avoids an increased laboratory workload.     

Outpatient needle aspiration biopsy of the prostate

The use of aspiration needle biopsy and needle biopsy of the prostate is described in 38 cases. Aspiration needle biopsy is a fast, safe and reliable procedure that requires no special equipment. It can be used as a preliminary office screening procedure in the diagnosis of carcinoma of the prostate.     

Flächenpressung unter Schrauben aus austenitischen Chrom-Nickel-Stählen

Allowable limits for loads under heads of fasteners out of stainless austenitic chromium nickel steels. Safety and load carrying capacity of fastened joints are determined through the strength of the fasteners, the pressure under the head and nuts which can be endured without plastic deformations and the variation of the actual preload. The strength of screws of stainless steels are known with its variations since long time. The allowable pressure under the head and nut of fasteners for the various austenitic chromium steels in the solution annealed and cold formed condition are not known so far. The result of such investigations for the important austenitic chromium steels are published herewith. The now known loadability limits must be recognized. After loading above these limits a recreational effect was observed for which interpretations and explanations still have to be found.     

Pilot scale exponential growth of Escherichia coli W to high cell concentration with temperature variation

An efficient method to grow Escherichia coli W to high cell concentrations on the pilot scale is described and discussed. The method involves growth linked introduction of glucose and ammonia to the culture, sparging with oxygen, and maintenance of aerobic conditions by gradually decreasing the temperature in the culture in order to keep the oxygen demand within the limits of the capacity of supply. Under these conditions the linear rate of cell mass production is actually the result of exponential growth with a gradually decreasing growth-rate constant. About 10 kg packed cells were produced in a 50 liter working-volume fermentor in one run of 13 hr. The concentration of the cells at the end of the growth was about 47 g dry cells/liter. The expenditure for nutrients was minimal and the controls were of simple automatic nature. From the determined yield constants for glucose, nitrogen, phosphorus, and oxygen it may be inferred that the cells grown by this method are similar to those grown exponentially at constant temperature.     

Driver judgments of relative car velocities.

In a study of the causes of rear end accidents, 11 Ss made judgments of the interval separating the car in which they were riding from a preceding car. Of 154 judgments, only 7 were potentially dangerous, although Ss "tended to underestimate the relative speed differential between their car and the one in front of it." From Psyc Abstracts 36:04:4LN61O. (PsycINFO Database Record (c) 2010 APA, all rights reserved)