18,029 research outputs found
Memory and self-induced shocks in an evolutionary population competing for limited resources
We present a detailed discussion of the role played by memory, and the nature
of self-induced shocks, in an evolutionary population competing for limited
resources. Our study builds on a previously introduced multi-agent system
[Phys. Rev. Lett 82, 3360 (1999)] which has attracted significant attention in
the literature. This system exhibits self-segregation of the population based
on the `gene' value p (where 0<=p<=1), transitions to `frozen' populations as a
function of the global resource level, and self-induced large changes which
spontaneously arise as the dynamical system evolves. We find that the large,
macroscopic self-induced shocks which arise, are controlled by microscopic
changes within extreme subgroups of the population (i.e. subgroups with `gene'
values p~0 and p~1).Comment: 27 pages, 31 figure
Optical data storage and metallization of polymers
The utilization of polymers as media for optical data storage offers many potential benefits and consequently has been widely explored. New developments in thermal imaging are described, wherein high resolution lithography is accomplished without thermal smearing. The emphasis was on the use of poly(ethylene terephthalate) film, which simultaneously serves as both the substrate and the data storage medium. Both physical and chemical changes can be induced by the application of heat and, thereby, serve as a mechanism for high resolution optical data storage in polymers. The extension of the technique to obtain high resolution selective metallization of poly(ethylene terephthalate) is also described
A simple opto-fluidic switch detecting liquid filling in polymer-based microfluidic systems
A novel detection scheme for detection of liquid levels and bubbles in microfluidic systems, using the principle of total internal reflection (TIR) is presented. A laser beam impinges on the side walls of a channel which are inclined at 45deg. In an unfilled channel of such a "V-groove", TIR deflects the beam by 90deg into a simple light detector. Upon the presence of liquid, the refractive index in the channel changes, thus eliminating deflection by TIR. The detection principle is robust, requiring no calibration, and tolerating alignment errors of the laser larger than the width and depth of the microfluidic channels. The machining of the V-groves can seamlessly be integrated into common polymer microfabrication schemes such as injection molding
Leverage and productivity growth in emerging economies: Is there a threshold effect?
While credit is essential for investment, innovation and economic growth, there are risks to unfettered credit booms. The present paper provides an innovative micro-economic approach to identify the threshold leverage beyond which corporate indebtedness becomes âexcessiveâ. In particular, the paper hypothesizes a non-linear relationship in that moderate leverage could boost growth while very high leverage could restrict total factor productivity growth, through increased likelihood of financial distress and bankruptcy. Estimates of a threshold model for a group of emerging CEE countries confirm the non-linear relationship, after controlling for various firm, industry and financial market characteristics.Financial support from ESRC grant RES-062-23-0986 is gratefully acknowledge
Pressure-energy correlations and thermodynamic scaling in viscous Lennard-Jones liquids
We use molecular dynamics simulation results on viscous binary Lennard-Jones
mixtures to examine the correlation between the potential energy and the
virial. In accord with a recent proposal [U. R. Pedersen et. al. Phys. Rev.
Lett. 100, 015701 (2008)], the fluctuations in the two quantities are found to
be strongly correlated, exhibiting a proportionality constant, Gamma,
numerically equal to one-third the slope of an inverse power law approximation
to the intermolecular potential function. The correlation is stronger at higher
densities, where interatomic separations are in the range where the inverse
power law approximation is more accurate. These same liquids conform to
thermodynamic scaling of their dynamics, with the scaling exponent equal to
Gamma. Thus, the properties of strong correlation between energy and pressure
and thermodynamic scaling both reflect the ability of an inverse power law
representation of the potential to capture interesting features of the dynamics
of dense, highly viscous liquids.Comment: 5 pages, 4 figures; published version, one figure remove
Evolutionary quantum game
We present the first study of a dynamical quantum game. Each agent has a
`memory' of her performance over the previous m timesteps, and her strategy can
evolve in time. The game exhibits distinct regimes of optimality. For small m
the classical game performs better, while for intermediate m the relative
performance depends on whether the source of qubits is `corrupt'. For large m,
the quantum players dramatically outperform the classical players by `freezing'
the game into high-performing attractors in which evolution ceases.Comment: 4 pages in two-column format. 4 figure
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