Components Of Defense System Research Articles

Studies on lipid peroxidation in rat tissues following administration of low and moderate doses of cadmium chloride

The susceptibility to lipid peroxidation (LPO) of liver, kidneys, brain, lungs, heart, and testes was assessed in rats administered intraperitoneally with various doses of cadmium (Cd). Dose-response studies were carried out with male Long Evans rats (12-week-old; 300 ± 33 g) injected with 25, 125, 500, and 1250 μg Cd/kg as CdCl 2 and sacrificed after 24 h. In time-response studies, animals were administered with 25 and 500 μg Cd/kg as CdCl 2 and sacrificed after 2, 6, 12, 24, and 72 h. Exposure of rats to low and moderate doses of Cd by the intraperitoneal route stimulated LPO in all the tissues investigated as assessed by the measurement of thiobarbituric acid reactive substances (TBARS). Lungs and brain were the most responsive, and these tissues and liver displayed early responses following Cd exposure. Comparison of LPO to various tissue indicators (for liver: alanine aminotransferase (ALT), sorbitol dehydrogenase (SDH), alkaline phosphatase (ALP); for lungs: ALP, gamma-glutamyl transpeptidase (GGT)) suggested that low doses of Cd stimulated LPO without any evidence of acute damages. These results suggest that LPO is an early and sensitive consequence of Cd exposure as determined in various organs. Investigation of liver, lungs, and heart antioxidant defense system components (glutathione peroxidase (GPX), glutathione reductase (GR), glucose-6-phosphate dehydrogenase (G6PDH), superoxide dismutase (SOD)) revealed that GPX might be considered as a potential modulator of the Cd-induced LPO reaction in lungs and heart tissues.

The Software Life Cycle—A Management and Technological Challenge in the Department of Defense

The importance of software in defense systems continues to intensify as new systems emerge in response to increasing threats and declining force levels. The need to manage this software as a critical component of defense systems over their life cycle is becoming widely recognized. A general awareness of this need as an institutional problem requiring special attention within the Office of the Secretary of Defense has been growing as software problems have reached top level defense management visibility with increasing regularity. Software costs are continuing to multiply in step with advancing weapons systems sophistication, and opportunities for cost avoidance now are leveraged against large dollar investments. These conditions characterize the computer industry at large, but very little overall focus has been visible to improve the software development process. Consequently, the Department of Defense (DoD) has undertaken a two part effort to accelerate both near-term and long-term improvements in software development for weapons system applications. These efforts, the establishment of software life cycle management policy and practices, and the vigorous development and application of new software technology are discussed in considerable depth.

Inadequacy of Cost Per “Kill” as Measure of Effectiveness

Cost per enemy “kill” is a commonly used measure for determining the relative worth of competitive components for a defense system. If the defense system components are employed in such a manner that they do not affect each other, this measure of effectiveness appears to be suitable for many situations. If there are interactions among the components of a defense system, however, a comparison based on cost per enemy “kill” which is not obtained from consideration of the over-all defense system can be misleading. This paper presents an analysis which indicates that such misleading situations often exist. To perform this analysis, a somewhat simplified mathematical model is developed to represent the actions and outcomes of an enemy attack against a defense system. The mathematical model permits partial analytical treatment of moderately complicated attack-defense situations and may be useful in many types of military operations-research work.