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The effect of frustration upon performance on a motor task with high grade mental retardates
Darwin-Lagrangian Analysis for the Interaction of a Point Charge and a Magnet: Considerations Related to the Controversy Regarding the Aharonov-Bohm and Aharonov-Casher Phase Shifts
The classical electromagnetic interaction of a point charge and a magnet is
discussed by first calculating the interaction of point charge with a simple
model magnetic moment and then suggesting a multiparticle limit. The Darwin
Lagrangian is used to analyze the electromagnetic behavior of the model
magnetic moment (composed of two oppositely charged particles of different mass
in an initially circular orbit) interacting with a passing point charge. The
changing mangetic moment is found to put a force back on a passing charge; this
force is of order 1/c^2 and depends upon the magnitude of the magnetic moment.
It is suggested that in the limit of a multiparticle magnetic toroid, the
electric fields of the passing charge are screened out of the body of the
magnet while the magnetic fields penetrate into the magnet. This is consistent
with our understanding of the penetration of electromagnetic velocity fields
into ohmic conductors. Conservation laws are discussed. The work corresponds to
a classical electromagnetic analysis of the interaction which is basic to
understanding the controversy over the Aharonov-Bohm and Aharonov-Casher phase
shifts and represents a refutation of the suggestions of Aharonov, Pearle, and
Vaidman.Comment: 33 page
MACS: Multi-agent COTR system for Defense Contracting
The field of intelligent multi-agent systems has expanded rapidly in the recent past. Multi-agent architectures and systems are being investigated and continue to develop. To date, little has been accomplished in applying multi-agent systems to the defense acquisition domain. This paper describes the design, development, and related considerations of a multi-agent system in the area of procurement and contracting for the defense acquisition community
Ingestion of a Nutritional Supplement Pre-Workout Will Increase Exercise Time-to-Fatigue
Everyone fatigues at the end of an intense exercise bout. However, previous research has indicated that ingestion of a mixed nutrient supplement one hour pre-exercise will increase exercise time-to-fatigue¹. For this experiment, four females between the ages 20-50 participated in a controlled pilot study. Exercise was performed using a row machine, where time- to-fatigue was measured from a baseline of 80% max HR (220 minus age). The nutrient supplement was ingested 1 hour pre-rowing and contained 30g of protein, 5g carbohydrate, and 3g of fat. Results showed that pre-exercise ingestion of a mixed protein supplement did increase row time-to-fatigue
Effects of antenatal betamethasone on preterm human and mouse ductus arteriosus: comparison with baboon data.
BackgroundAlthough studies involving preterm infants ≤34 weeks gestation report a decreased incidence of patent ductus arteriosus after antenatal betamethasone, studies involving younger gestation infants report conflicting results.MethodsWe used preterm baboons, mice, and humans (≤276/7 weeks gestation) to examine betamethasone's effects on ductus gene expression and constriction both in vitro and in vivo.ResultsIn mice, betamethasone increased the sensitivity of the premature ductus to the contractile effects of oxygen without altering the effects of other contractile or vasodilatory stimuli. Betamethasone's effects on oxygen sensitivity could be eliminated by inhibiting endogenous prostaglandin/nitric oxide signaling. In mice and baboons, betamethasone increased the expression of several developmentally regulated genes that mediate oxygen-induced constriction (K+ channels) and inhibit vasodilator signaling (phosphodiesterases). In human infants, betamethasone increased the rate of ductus constriction at all gestational ages. However, in infants born ≤256/7 weeks gestation, betamethasone's contractile effects were only apparent when prostaglandin signaling was inhibited, whereas at 26-27 weeks gestation, betamethasone's contractile effects were apparent even in the absence of prostaglandin inhibitors.ConclusionsWe speculate that betamethasone's contractile effects may be mediated through genes that are developmentally regulated. This could explain why betamethasone's effects vary according to the infant's developmental age at birth
Exploration and exploitation in the presence of network externalities
This paper examines the conditions under which exploration of a new, incompatible technologyis
conducive to firm growth in the presence of network externalities. In particular,
this studyis motivated bythe divergent evolutions of the PC and the workstation markets in
response to a new technology: reduced instruction set computing (RISC). In the PC market,
Intel has developed new microprocessors bymaintaining compatibilitywith the established
architecture, whereas it was radicallyr eplaced byRISC in the workstation market. History
indicates that unlike the PC market, the workstation market consisted of a large number
of power users, who are less sensitive to compatibilitythan ordinaryusers. Our numerical
analysis indicates that the exploration of a new, incompatible technologyis more likelyto
increase the chance of firm growth when there are a substantial number of power users or
when a new technologyis introduced before an established technologytakes off.
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Weighted-density approximation for general nonuniform fluid mixtures
In order to construct a general density-functional theory for nonuniform
fluid mixtures, we propose an extension to multicomponent systems of the
weighted-density approximation (WDA) of Curtin and Ashcroft [Phys. Rev. A 32,
2909 (1985)]. This extension corrects a deficiency in a similar extension
proposed earlier by Denton and Ashcroft [Phys. Rev. A 42, 7312 (1990)], in that
that functional cannot be applied to the multi-component nonuniform fluid
systems with spatially varying composition, such as solid-fluid interfaces. As
a test of the accuracy of our new functional, we apply it to the calculation of
the freezing phase diagram of a binary hard-sphere fluid, and compare the
results to simulation and the Denton-Ashcroft extension.Comment: 4 pages, 4 figures, to appear in Phys. Rev. E as Brief Repor
Can filesharers be triggered by economic incentives? Results of an experiment
Illegal filesharing on the internet leads to considerable financial losses for artists and copyright owners as well as producers and sellers of music. Thus far, measures to contain this phenomenon have been rather restrictive. However, there are still a considerable number of illegal systems, and users are able to decide quite freely between legal and illegal downloads because the latter are still difficult to sanction. Recent economic approaches account for the improved bargaining position of users. They are based on the idea of revenue-splitting between professional sellers and peers. In order to test such an innovative business model, the study reported in this article carried out an experiment with 100 undergraduate students, forming five small peer-to-peer networks.The networks were confronted with different economic conditions.The results indicate that even experienced filesharers hold favourable attitudes towards revenue-splitting.They seem to be willing to adjust their behaviour to different economic conditions
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