Bound states and extended states around a single vortex in the d-wave superconductors

Making use of the Bogoliubov-de Gennes equation for the d-wave superconductors, we investigate the quasi-particle spectrum around a single vortex. Taking $p_F\xi=10$, we found that there are bound states which are localized around the vortex core, and extended states which are rather uniform, for $|E|<\Delta$ where $E$ is the quasi-particle energy and $\Delta$ is the asymptotic value of the order parameter for away from the vortex.Comment: 4 pages, 6 figure

Jonathan Steele: Inside East Germany. The state that came in from the cold

New York: Urizen, 1977. 227 p

An Analysis of the Traveler\u27s Dilemma with Experimental Evidence

Game theory studies how people should respond in strategic situations and is naturally used for predictive purposes. The optimal strategy predictions yielded by game theoretic reasoning can be surprising when they conflict with preconceived notions of how to play, i.e. the common sense strategy. Consequently, the game theoretically optimal strategy may be a poor predictor of how individuals actually behave in real-life strategic situations. In order to accurately model such situations for predictive purposes it is important to know the limitations of the current game theoretic tools. In the traveler\u27s dilemma, Kaushik Basu presents a parable to illustrate how game theoretic reasoning and intuition can be at odds. The parable is as follows: Two travelers are returning home from a vacation where they purchased identical souvenirs. These souvenirs are, of course, routinely destroyed by the airline. The souvenirs were purchased with cash in an open-air market and as a result the travelers do not have receipts. The airline official in charge of damage claims wants to compensate the travelers fairly but has no way of determining the actual purchase price of the souvenirs. In an attempt to avoid spurious claims the official proposes a method to determine the amount awarded. Each traveler must submit a claim that lies between a known minimum and maximum. (The minimum bound can be thought of as that level of claim below which the airline never disputes for cost reasons and the maximum bound can be thought of as the most the airline\u27s insurance company would pay absent a special policy). If the claims submitted are equal then both receive the amount claimed. However, if traveler 1 submits a lower claim than traveler 2, traveler 1 is considered honest and receives the lower claim plus a reward for honesty (ideally in frequent flyer miles thereby ensuring that the airline will have an opportunity to destroy those items which it missed on the first pass). Traveler 2 also receives the lower claim but in addition a symmetric penalty for lying is levied. Travelers report their claims simultaneously i.e., without knowledge of the other traveler\u27s claim. This ensures that simple, collusive agreements cannot be reached because any such agreement involves a non-credible promise (the rewards are structured such that there it is never in a rational player\u27s best interest to play as he agreed). Game theoretic analysis suggests that two rational players will report the minimum claim. Moreover, this result is a direct consequence of both players attempting to maximize their individual payoff. Adoption of this strategy does not, on the face of it, appear to be the best strategy because both players can clearly improve their payoff simply by submitting random large claims

Will the valuation ratios revert to their historical means? Some evidence from breakpoint tests

If valuation ratios return to their historical means any time soon, then equity prices must fall substantially, or earnings and dividends must accelerate sharply, or some combination of these events must occur. Historical patterns over the past century suggest that stock prices will fall to align valuation ratios with their means. Of course, the means of the valuation ratios could have changed. To assess the likelihood of such changes, the authors employ breakpoint tests, which allow for multiple breakpoints at unknown break dates. The authors also review alternative explanations for changes in the ratios. They conclude that although no single explanation may be convincing by itself, taken in toto with empirical evidence of structural change, the preponderance of evidence suggests that the mean of the dividend-price ratio is now somewhere between 1% and 2%, probably nearer to 1%. They also conclude that the mean price-to-earnings ratio is now somewhere between 20 and 25, perhaps even higher.Stock - Prices

Forest regeneration and future stand trajectories following mountain pine beetle-caused lodgepole pine mortality

2014 Fall.A mountain pine beetle (MPB) (Dendroctonus ponderosae) outbreak that began in the late 1990s has killed lodgepole pine (Pinus contorta var. latifolia) on up to 10 million hectares in western North America. Over one million hectares have been affected in northern Colorado and southern Wyoming. The large footprint of this disturbance has prompted widespread concern about the composition, structure, and function of forests as they develop following MPB. In this dissertation, I ask how variation in species composition and mortality level will affect the future forest in the Southern Rockies. I used forest growth models to predict forest structure and fuel loads during the century after MPB outbreak. I compared three lodgepole pine-dominated forest types (all > 80 % lodgepole by basal area) and the simulated effects of no-action and fuel reduction treatments. Forest with Engelmann spruce (Picea engelmannii) and subalpine fir (Abies lasiocarpa var. lasiocarpa) became much more dominated by these species, resulting in highly hazardous canopy fuels. In contrast, stands of lodgepole and aspen (Populus tremuloides) did not shift composition and did not show a marked increase in fire hazard. The effects of management were also differed: hazardous fuels were best mitigated in the forest types with spruce and fir, but treatment had few positive effects in the stands of only lodgepole and aspen due to their lower hazard without treatment. The results show management of lodgepole-dominated forests must consider even subtle variation in composition to be effective. I also examined post-outbreak regeneration in these forests. In mixed lodgepole pine and aspen stands, I asked if regeneration is sufficient to reforest areas affected by MPB. Both species excel in high light environments that are created by overstory mortality, but lodgepole pine is thought to require ground disturbance to regenerate. Aspen regeneration can be prevented by browsing. I found lodgepole regeneration is occurring in 85% of stands, and all stands had aspen sucker density above 1000 stems ha-1. Many suckers are damaged by browsing, but my results suggest that sufficient quantities of down lodgepole pine may protect suckers and allow them to recruit to the overstory. Overall, I conclude aspen and lodgepole forests are regenerating successfully and that these areas will remain mixed forests of both species in the future. Finally, I measured the effects of mortality level on regeneration. I compared regeneration density and growth of lodgepole, spruce, and fir in high (85% of basal area) and moderate (40% of basal area) mortality forest. Lodgepole pine regeneration density and growth was high where outbreak was most severe, though all species grew faster in high mortality than moderate mortality. All three species will likely be important to future forest in areas with high mortality, and lodgepole pine will play a substantial role. In contrast, in moderate mortality areas lodgepole pine regeneration is nearly absent and spruce and fir are growing fastest. Here the forest understory will be made up of shade tolerant species, and the forest will become progressively more dominated by these species as this stratum develops

Mutual funds, fee transparency, and competition

Mutual funds enable small, less experienced investors to hold diversified portfolios of stocks and bonds at relatively low costs. Though the mutual fund market is competitive in many ways, fees can vary substantially for what are essentially identical products. This may be due to bundling of services, but it may also reflect some confusion on the part of less experienced investors, which inhibits comparative shopping among funds. Suggested reforms for improved fee disclosure seek to make fees more transparent for less informed investors and should improve competitive discipline among funds.Mutual funds

Magneto-Optical Spectrum Analyzer

We present a method for the investigation of gigahertz magnetization dynamics of single magnetic nano elements. By combining a frequency domain approach with a micro focus Kerr effect detection, a high sensitivity to magnetization dynamics with submicron spatial resolution is achieved. It allows spectra of single nanostructures to be recorded. Results on the uniform precession in soft magnetic platelets are presented.Comment: 5 pages, 7 figure

On pressure and temperature waves within a cavitation bubble

The presented work is about the detailed pressure, temperature and velocity distribution within a plane, cylindrical and spherical cavitation bubble. The review of Plesset & Prosperetti (1977) and more recently the review of Feng & Leal (1997) describe the time behavior of the gas within a spherical bubble due to forced harmonic oscillations of the bubble wall. We reconsider and extend those previous works by developing from the conversation laws and the ideal gas law a boundary value problem for the distribution of temperature and velocity amplitude within the bubble. This is done for a plane, cylindrical, or spherical bubble. The consequences due to shape differences are discussed. The results show that an oscillating temperature boundary layer is formed in which the heat conduction takes places. With increasing dimensionless frequency, i.e. Péclet number, the boundary-layer thickness decreases and compression modulus approaches its adiabatic value. This adiabatic behaviour is reached at lower frequencies for the plane geometry in comparison with cylindrical and spherical geometry. This is due to the difference in the volume specific surface, which is 1, 2, 3 times the inverse bubble height/radius for the plane, cylindrical and spherical bubble respectively. For the plane bubble the analysis ends up in an eigenvalue problem with four eigenvalues and modes. The analytical result is not distinguishable from the numerical result for the plane case gained by a finite element solution. Interestingly if the diffusion time for the temperature distribution is of the order of the traveling time of a pressure wave no adiabatic behavior is observed. A parameter map for the different regimes is given. Since only the behavior of the gas within the bubble is considered the analysis is independent of the surface tension coefficient and the inertia of the surrounding liquid. For the plane bubble since there is no curvature there is no pressure change over the free surface. Despite of this a plane bubble is manly academic, since due to inertia the pressure within the fluid would have to be infinity if the liquid volume around the bubble is unbounded.http://deepblue.lib.umich.edu/bitstream/2027.42/84253/1/CAV2009-final57.pd

A People's History of Modern Europe

From the monarchical terror of the Middle Ages to the mangled Europe of the Twenty-first Century, A People's History of Modern Europe tracks the history of the continent through the deeds of those whom mainstream history tries to forget. Europe provided the perfect conditions for a great number of political revolutions from below. The German peasant wars of Thomas Müntzer, the bourgeoisie revolutions of the eighteenth century through to the rise of the industrial worker in England and the turbulent journey of the Russian Soviets, the role of the European working class throughout the Cold War, students in 1968 and through to the present day, where we continue to fight to forge an alternative to the barbaric economic system. With sections focusing on the role of women, this history sweeps away the tired platitudes of the privileged which our current understanding is based upon, and provides an opportunity to see our history differently