Computer Sciences Corporation

About: Computer Sciences Corporation is a based out in . It is known for research contribution in the topics: Spacecraft & Software development. The organization has 1916 authors who have published 2389 publications receiving 62729 citations. The organization is also known as: CSC.

Boron abundances in early b stars: results from the b iii resonance line in iue data

Abstract: We have used archival International Ultraviolet Explorer high-dispersion SWP spectra to study the B III resonance line at 2065.8 A in 44 early B stars. We find a median boron abundance about half that of solar system meteoritic material, consistent with the values found from previous studies of boron in early B stars. About one-third of the stars studied appear to have boron abundances that are a factor of 4 or more lower than this median. Many of these are stars with enhanced nitrogen abundances, confirming the belief that deep envelope mixing can occur in main-sequence B stars. A few stars with low boron abundances have normal N/C ratios. It is unclear whether all of these can be explained as stars where mixing depleted the boron but did not go deep enough to bring CN-processed material to the surface or if some stars were actually formed with an unusually low boron abundance.

A Physical Meteor-Burst Propagation Model and Some Significant Results for Communication System Design

Abstract: This paper describes a meteor-burst communication model based on physical models and astronomical observations of meteor orbits and flux. It compares model results to experimental results and uses them to illuminate this complex propagation medium and to show how "hot spots" of meteor activity vary in position and relative importance with the fundamental meteor-burst link parameters. It also presents antenna and other meteor-burst link design considerations with emphasis on military systems.

Rat poison and food security in the People’s Republic of China: focus on tetramethylene disulfotetramine (tetramine)

Abstract: The last several years have seen a large number of mass poisonings in mainland China, particularly those caused by illicit rodenticides. One rat poison, tetramine (tetramethylene disulfotetramine) is responsible for a great percentage of death and injury in the People’s Republic of China (PRC). Tetramine is an acutely toxic substance with human oral toxicity estimated as low as 0.1 mg/kg, and is widely available in open markets in mainland China—this despite being prohibited for manufacture or sale in the PRC. Being a GABA antagonist, and having an extremely potent effect on the brain stem, many victims can quickly fall into convulsions and die within hours following ingestion. With no known effective antidote at this time, clinical data from the PRC show that acute cases of tetramine poisoning are extremely difficult to treat. The widespread use of tetramine—including its reported sale at a Malaysian outdoor market in September 2002—could exacerbate its hazard to public health, particularly in those areas having large overseas Chinese populations.

Spectral synthesis in the ultraviolet. III - The spectral morphology of normal stars in the mid-ultraviolet

Abstract: The morphology of 218 mid-UV spectra of stars ranging from O through K in spectral type is examined. Several new line and continuum indices are defined and their usefulness as temperature, luminosity, and metallicity discriminants is discussed. Mid-UV stellar continua are found to be markedly affected by abundance. A UV excess, delta(2600-V), is computed which is more sensitive by a factor of 10 to (Fe/H) than is delta(U-B). The relative strength of spectral lines in the mid-UV is not as strongly affected by abundance. Mid-UV spectra are much more sensitive to the temperature of the stellar population than to either metallicity or the dwarf/giant ratio. Mg II 2800 shows unexpected behavior, displaying no sensitivity to abundance for cool stars and a reversed sensitivity in FG dwarfs such that metal-poor stars have stronger Mg II strengths at the same temperature than more metal-rich stars.