The construction of an achievement test in plane geometry

Thesis (M.S.Ed.)--University of Kansas, Education, 1926

Unmanned aerial vehicle survivability the impacts of speed, detectability, altitude, and enemy capabilities

Warfighters are increasingly relying on Unmanned Aerial Vehicle (UAV) systems at all levels of combat operations. As these systems weave further into the fabric of our tactics and doctrine, their loss will seriously diminish combat effectiveness. This makes the survivability of these systems of utmost importance. Using Agent-based modeling and a Nearly Orthogonal Latin Hypercube design of experiment, numerous factors and levels are explored to gain insight into their impact on, and relative importance to, survivability. Factors investigated include UAV speed, stealth, altitude, and sensor range, as well as enemy force sensor ranges, probability of kill, array of forces, and numerical strength. These factors are varied broadly to ensure robust survivability results regardless of the type of threat. The analysis suggests that a speed of at least 135 knts should be required and that increases in survivability remain appreciable up to about 225 knts. The exception to speed's dominance is in the face of extremely high capability enemy assets. In this case, stealth becomes more important than speed alone. However, the interactions indicate that as both speed and stealth increase, speed yields a faster return on overall survivability and that speed mitigates increased enemy capabilities.http://archive.org/details/unmannederialveh109451948Approved for public release; distribution is unlimited

Nitrite Mode of Action: The Inhibition of Yeast Pyruvate Decarboxylase and Clostridial Pyruvate:ferredoxin Oxidoreductase by Nitric Oxide and Menadione

136 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1988.Nitrite mode of action as an anticlostridial agent was investigated by studying nitric oxide (NO) inhibition of thiamin dependent pyruvate decarboxylases. Two enzymatic decarboxylation systems were studied: pyruvate decarboxylate (PD) from brewer's yeast which catalyzes the non-oxidative decarboxylation of pyruvate and pyruvate:ferredoxin oxidoreductase (PFO) from Clostridium perfringens (CP; ATCC no. 3624A) which catalyzes the oxidative decarboxylation of pyruvate in clostridia. Menadione (MD), which was previously observed to inhibit pyruvate dehyrogenase from pigeon breast muscle in a similar manner to NO, was studied as a possible nitrite alternative.PD was inhibited by NO (50% inhibition @ 0.5mM) under anaerobic but not under aerobic conditions; prior inhibition was not reversed by aerobic conditions. Sodium nitrite (0.5 mM) was not inhibitory. Inhibition of PD by NO was markedly enhanced in the presence of ascorbate. Inhibition of PD by NO appeared to be non-competitive.A purified preparation of PFO from CP was characterized with respect to molecular weight (255,000 daltons), subunit composition (dimer 127,000 daltons each), temperature optimum (45\sp\circC), pH optimum (pH 7.5), Michaelis constant (Km pyruvate = 1.0 mM), and NADH oxidase activity (positive). The effects of NO on PFO resulted in non-competitive inhibition (Ki apparent = 0.015 mM). NADH oxidase activity of PFO was also inhibited by NO. Nitrate was not inhibitory under anaerobic testing conditions at concentrations of 1.0 mM.MD was found to inactivate PD (Ki apparent = 0.065 mM). Inactivation was dependent on the presence of substrate and increased under anaerobic conditions implying a paracatalytic mechanism of inhibition. Structure activity relationships were analyzed for other naphthoquinones, phenolic antioxidants, and known sulfhydryl groups reagents. All the naphthoquinones (NQ) tested were inhibitory at the 0.05 mM concentration (vitamin K\sb4, 13.7%, 1,2-NQ 42%, 1,4-NQ 58%, 1,2-NQ-4-sulfonic acid 33%, 1,4-NQ-2-sulfonic acid 28%) except vitamin K\sb1 and 2,3-dimethyl-1,4-NQ. Incubation of PD with sulfhydryl inhibitors (5$\prime,5\prime$ dithiobis-(2-nitrobenzoic acid), N-ethylmaleimide, or iodoacetate) produced slight inhibition at the 0.5 mM concentration (12.7%, 6.9%, 5.1%) whereas p-chloromercuribenzoic acid inhibited 56.5% at 0.005 mM. Phenolic antioxidants were not significantly inhibitory at 0.1 mM concentration.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD