26,929 research outputs found
Field resonance propulsion concept
A propulsion concept was developed based on a proposed resonance between coherent, pulsed electromagnetic wave forms, and gravitational wave forms (or space-time metrics). Using this concept a spacecraft propulsion system potentially capable of galactic and intergalactic travel without prohibitive travel times was designed. The propulsion system utilizes recent research associated with magnetic field line merging, hydromagnetic wave effects, free-electron lasers, laser generation of megagauss fields, and special structural and containment metals. The research required to determine potential, field resonance characteristics and to evaluate various aspects of the spacecraft propulsion design is described
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Abundance and distribution of larval fishes and shrimps in the Laguna Madre, Texas : a hypersaline lagoon
To Texas Water Development BoardContract nos. IAC (88-89)1636 and (90-91)0751October 1990Tidal inlets connecting the Gulf of Mexico with estuarine waters are widely spaced and relatively narrow along the Texas coast. These inlets provide the sole route for ingress of larvae to the estuary for estuarine-dependent marine species and the egress of juveniles and sub-adults of these species back to the ocean. This study was an investigation of the abundance and distribution of ichthyoplankton of selected fishes and shrimps in an area where the opening and maintenance of a new tidal pass has been proposed in the Laguna Madre, a sub-tropical, hypersaline lagoon along the southern Texas coast. Surface and bottom ichthyoplankton samples were taken bimonthly in four zones in the Laguna Madre in areas which were directly influenced by tidal inlets from the Gulf of Mexico and areas isolated from such connections. Seasonal composition of the ichthyoplankton was similar to that reported from other Gulf of Mexico and southeastern United States estuaries with winter catches dominated by offshore spawners and summer catches dominated by inshore and estuarine spawners. The pelagic larvae of three species of estuarine spawners, bay anchovy (Anchoa mitchilli), spotted seatrout (Cynoscion nebulosus), and black drum (Pogonias cromis), were common throughout the Laguna Madre at salinities up to 50°/00. Pelagic larvae of offshore spawners were abundant only in the area near the tidal inlet and only a few individuals were found dispersed throughout the lagoon. The majority of these species are distributed throughout the Laguna Madre as juveniles but the dispersion or advection of these species to areas not closely associated with tidal inlets occurs at development stages older than the pelagic larval stage. These data suggest that opening and maintaining a tidal inlet in the upper Laguna Madre would increase the opportunity for recruitment of larvae of offshore spawners into an area currently unoccupied by these life-history stages.Marine Scienc
Evaluation of an anthropomorphic user interface in a travel reservation context and affordances
This paper describes an experiment and its results concerning research that has been going on for a number ofyears in the area of anthropomorphic user interface feedback. The main aims of the research have been to examine theeffectiveness and user satisfaction of anthropomorphic feedback in various domains. The results are of use to all interactivesystems designers, particularly when dealing with issues of user interface feedback design. There is currently somedisagreement amongst computer scientists concerning the suitability of such types of feedback. This research is working toresolve this disagreement. The experiment detailed, concerns the specific software domain of Online Factual Delivery in thespecific context of online hotel bookings. Anthropomorphic feedback was compared against an equivalent non-anthropomorphicfeedback. Statistically significant results were obtained suggesting that the non-anthropomorphic feedback was more effective.The results for user satisfaction were however less clear. The results obtained are compared with previous research. Thissuggests that the observed results could be due to the issue of differing domains yielding different results. However the resultsmay also be due to the affordances at the interface being more facilitated in the non-anthropomorphic feedback
Risk Aversion and Incentive Effects
A menu of paired lottery choices is structured so that the crossover point to the high-risk lottery can be used to infer the degree of risk aversion. With "normal" laboratory payoffs of several dollars, most subjects are risk averse and few are risk loving. Scaling up all payoffs by factors of twenty, fifty, and ninety makes little difference when the high payoffs are hypothetical. In contrast, subjects become sharply more risk averse when the high payoffs are actually paid in cash. A hybrid "power/expo" utility function with increasing relative and decreasing absolute risk aversion nicely replicates the data patterns over this range of payoffs from several dollars to several hundred dollars
An experimental study of costly coordination
This paper reports data for coordination game experiments with random matching. The experimental design is based on changes in an effort-cost parameter, which do not alter the set of Nash equilibria nor do they alter the predictions of adjustment theories based on imitation or best response dynamics. As expected, however, increasing the effort cost lowers effort levels. Maximization of a stochastic potential function, a concept that generalizes risk dominance to continuous games, predicts this reduction in efforts. An error parameter estimated from initial two-person, minimum-effort games is used to predict behavior in other three-person coordination games
An explanation of anomalous behavior in models of political participation
This paper characterizes behavior with “noisy” decision making for models of political interaction characterized by simultaneous binary decisions. Applications include: voting participation games, candidate entry, the volunteer's dilemma, and collective action problems with a contribution threshold. A simple graphical device is used to derive comparative statics and other theoretical properties of a “quantal response” equilibrium, and the resulting predictions are compared with Nash equilibria that arise in the limiting case of no noise. Many anomalous data patterns in laboratory experiments based on these games can be explained in this manner
Three-body forces and proton-rich nuclei
We present the first study of three-nucleon (3N) forces for proton-rich
nuclei along the N=8 and N=20 isotones. Our results for the ground-state
energies and proton separation energies are in very good agreement with
experiment where available, and with the empirical isobaric multiplet mass
equation. We predict the spectra for all N=8 and N=20 isotones to the proton
dripline, which agree well with experiment for 18Ne, 19Na, 20Mg and 42Ti. In
all other cases, we provide first predictions based on nuclear forces. Our
results are also very promising for studying isospin symmetry breaking in
medium-mass nuclei based on chiral effective field theory.Comment: 5 pages, 4 figures, minor changes, published versio
Classroom Games: A Prisoner's Dilemma
Game theory is often introduced in undergraduate courses in the context of a prisoner's dilemma paradigm, which illustrates the conflict between social incentives to cooperate and private incentives to defect. We present a very simple card game that efficiently involves a large number of students in a prisoner's dilemma. The extent of cooperation is affected by the payoff incentives and by the nature of repeated interaction. The exercise can be used to stimulate a discussion of a wide range of topics such as bankruptcy, quality standards, or price competition.prisoner's dilemma, game theory, experimental economics, classroom experiments
A Comparison of Electrical Breakdown Characteristics of Composite Materials Prepared With Unmodified Micro and Nano Scale Barium Titanate
High permittivity polymer matrix composites (PMCs) have been widely researched, especially in the field of microelectronics. For this study, high permittivity materials were investigated for their potential to form part of a multi-layer electric field detector. The two main requirements for such composites were high permittivity and a dielectric strength comparable to most standard polymers used as dielectric materials. Polystyrene was selected as a host polymer due to its high dielectric strength and amorphous structure. Barium titanate, a ferroelectric ceramic from the perovskite family, was selected as a high permittivity filler. Polymer permittivity in PMCs is usually orders of magnitude lower compared to the filler permittivity, although the resultant permittivity of the composite is generally markedly lower than the permittivity of the filler may suggest. This is because very little energy is stored in the ceramic filler, such that any increase in composite permittivity is due to an increase in the average field with the polymer matrix.[1]Micro and nano scale barium titanate was blended into polystyrene in an effort to discern the initial differences between composites prepared with the two different filler types. It was found that the micro scale barium titanate was well dispersed and from studying SEM micrographs, appeared to have a good particle size distribution. The nanoscale barium titanate was found to be very poorly dispersed in polystyrene, with a wide particle size distributions formed of weakly bound aggregations and some seemingly chemically bonded agglomerations which were regular in shape with a surface texture which was indicative of tightly bound primary particles. Consistent with the differences in particle dispersion within the micro and nano composites, there was a marked difference in AC breakdown strength between the different materials. All electrical breakdown data was analysed using a 2 parameter Weibull distribution. Figure 1 compares the ? values for the micro and nano composites at different filler loadings.<br/
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