Irradiation effects studies of NERVA materials

Several materials used in the NERVA project were irradiated at cryogenic temperatures to neutron fluences between 10 to the 17th and 10 to the 19th power newtons per square centimeter. Tensile properties were determined over a temperature range to evaluate the effects of irradiation on the material properties. The expected radiation damage typical of other materials was observed. A general increase in strength and decrease in ductility occurred. The effects at liquid nitrogen temperatures are more pronounced since radiation induced defects are not annealed out

Comparison of display enhancement with intelligent decision-aiding

Currently, two main approaches exist for improving the human-machine interface component of a system in order to improve overall system performance, display enhancement and intelligent decision aiding. Each of these two approaches has its own set of advantages and disadvantages, as well as introduce its own set of additional performance problems. These characteristics should help identify which types of problem situations and domains are better aided by which type of strategy. The characteristic issues are described of these two decision aiding strategies. Then differences in expert and novice decision making are described in order to help determine whether a particular strategy may be better for a particular type of user. Finally, research is outlined to compare and contrast the two technologies, as well as to examine the interaction effects introduced by the different skill levels and the different methods for training operators

Hypnozoites in Plasmodium: Do Parasites Parallel Plants?

The phenomenon of relapsing malaria has been recognised for centuries. It is caused in humans by the parasite species Plasmodium vivax and Plasmodium ovale, which can arrest growth at an early, asymptomatic stage as hypnozoites inside liver cells. These dormant parasites can remain quiescent for months or years, then reactivate causing symptomatic malaria. The dynamics of hypnozoite dormancy and reactivation are well documented but the molecular basis remains a complete mystery. Here, I observe that the process has striking parallels with plant vernalisation, whereby plants remain dormant through the winter before flowering in spring. Vernalisation is thoroughly studied in several plant species and its mechanisms are known in exquisite detail. Vernalisation may thus provide a useful framework for interrogating hypnozoite biology.European Research Council [Plasmocycle]

Missing the marks? Dispersion in corporate bond valuations across mutual funds

We study the dispersion of month-end valuations placed on identical corporate bonds by different mutual funds. Such dispersion is related to bond-specific characteristics associated with liquidity and market volatility. TRACE may have contributed to the general decline in dispersion over our sample period, though other factors most likely played roles. Further tests reveal marking patterns to be consistent with returns smoothing behavior by managers. Funds with ambiguous marking policies and those holding 'hard-to-mark' bonds appear more prone to smooth reported returns. From a regulatory perspective, we see little downside to requiring funds to explicitly state their marking standards. --

Pascal Spreading of Short-Term Interest Rate Contracts

This paper examines the spreading and pricing of short-term interest rate futures contracts and shows how traditional types of calendar spread positions can emerge as explicit arbitrage solutions. A specific set of intuitive spreading structures – “Pascal’s Spreading Triangle” – arises when the underlying daily risk factors are identified as the stochastic coefficients of a high-ordered polynomial approximation to the yield curve. No empirically estimated hedge ratios are required for these arbitrage strategies. Application of this Pascal Spreads framework to pricing and trading the LIFFE’s Short Sterling deposit futures market over the 1989 to 1998 sample period reveals that the LIFFE’s Short Sterling arbitrage sector’s efficiency has improved markedly over time. The improvement over the decade coincides with the dramatic declines in futures trading transactions costs. As a byproduct, the framework extracts and measures the quantitative impact of the Y2K millennium-turn pricing distortion on the December 1999 Short Sterling futures contract

Crisis Dynamics of Implied Default Recovery Ratios: Evidence From Russia and Argentina

The Russian GKO default crisis provides a unique window into the impact of changing default probabilities and recovery ratio assumptions on credit-sensitive sovereign bond prices. This paper introduces a joint implied parameter approach to extract both the expected recovery ratio and the default probability term structure. The methodology is applied to both Russian Federation and Republic of Argentina US dollar-denominated Eurobonds before and after the GKO crisis. For the Russian bonds, the sample paths suggest a two-phase revaluation. Shifts in default probabilities account for most of the initial price collapse. Marked decreases in the projected default recovery ratio dominate the continued Russian bond price declines. The "contagion effect" impact of the default crisis on the Argentine Eurobond market actually resembles the Russian case much more than the raw price data indicate. The crucial Argentine distinction is that investors never cut recovery value assumptions

A technique for passive attitude control of solar oriented interplanetary spacecraft

Passive damping technique for attitude control of solar orientated interplanetary spacecraf

Training programs and implementation process of positive youth development programs

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