Kovacs Effect in a Fragile Glass Model

The Kovacs protocol, based on the temperature shift experiment originally conceived by A.J. Kovacs for glassy polymers, is implemented in an exactly solvable dynamical model. This model is characterized by interacting fast and slow modes represented respectively by spherical spins and harmonic oscillator variables. Due to this fundamental property, the model reproduces the characteristic non-monotonic evolution known as the ``Kovacs effect'', observed in polymers, in granular materials and models of molecular liquids, when similar experimental protocols are implemented.Comment: 8 pages, 6 figure

Development Patterns and the Recreation Value of Amenities

Public open spaces around and within urban areas have been increasingly developed due to greater population pressures. My paper investigates if land around public open spaces is likely to get developed faster since households are attracted to the recreation value as well as the environmental amenities of the public open space. There has been inadequate attention in the literature to the influence of the different sources of value of open space on housing prices. While views of open space are certainly an important source of value to households, public open space is also valued because households enjoy recreation at the open space. Adopting the monocentric city model, simulations examine how the different sources of value of public open space influence the developed area, rent gradient and the development density of an urban area. The monocentric city model has residents competing for housing around a single central business district (CBD) while developers choose the density of development from the expected prices of the homes at that location in the city. Simulations of the closed city model result in equilibrium rent gradients for land and the housing, a utility level, and a city boundary. By referencing the monocentric city model with two-dimensional coordinates, Wu and Plantinga (2003) are able to more spatially explicitly examine the influence of amenities on the equilibrium state of the city. Amenities are shown to generate leap-frog development, influence the developed area of the city, the population density, rent gradients and location of different income groups. Although different shapes and areas of amenities are examined in their paper, there is no investigation of the proper proximity of these amenities to each other. Several small amenities dispersed far apart from each other in the city may result in less total amount of developed land than if there is only a single large amenity. Another reason that the proximity of amenities to each other matters is that the net benefits from recreation are influenced by the spatial arrangement of the amenities. Consumer´s surplus from recreation trips to the amenity is the net benefit of the amenity, with the price of a recreation trip including the travel cost to the amenity. The travel costs from recreation at amenities depend on how widely dispersed the amenities are in the city. While several amenities located widely throughout a city lower the travel costs of recreation, the city tends to diffuse more too resulting in a larger developed area. On the other hand, a single centrally located amenity contracts the city resulting in a smaller developed area although the travel costs of recreation rise slightly. Simulations from the model collect information on the aggregate amount of recreation trips, recreational net benefits, and the developed area. More localized benefits of amenities like nice views and cleaner air have a stronger influence on housing prices and development densities than the less localized benefits of amenities like recreation. If the travel costs for recreation are low, then only the localized benefits of amenities influence housing prices and development densities. However, if the demand for recreation and the travel costs to reach the amenity is high, the benefits of recreation have the potential to influence the housing prices and development densities in that area of the city. There are several potential solutions to the problem of recreation benefits of the amenities leading to the unwanted development of natural or agricultural land. The simplest solution is to regulate that no recreation take place at the amenity. Of course, the nice views and cleaner air may still draw development outward, and the enforcement of no recreation is necessary. Rather than prohibit recreation, raising user fees at recreation sites is a way to generate revenue for the city while simultaneously restraining sprawl. If the cost of travel to a recreation site is high, development is more likely near the site since households want the benefit of a trip without the high cost of travel to the site. If roads to the recreation site are improved to reduce the cost of travel, households will prefer to locate close to the central business district rather than the recreation site to reduce the cost of their daily commutes.Public Economics,

Magnetization and Loss Measurements of YBCO CORC and Roebel Cables for Accelerators using ±T dipole Susceptometer

This CORC sample Magnetization reaches about 900 kA/m (cable volume) and 2200 kA/m (strand volume) near injection This Roebel cable reaches about 2000 kA/m (cable volume) and 2400 kA/m (strand volume) near injection These values agree well with individual tape values if (i) we normalize to strand volume, Correct CORC for twisting These values can be compared to NbTi Minj = 10 kA/m b3 = 3-6 units Nb3Sn Minj = 100 kA/m b3 = 30 units Here Minj is 100 X higher than NbTi and 10 X higher than NbTi Not insurmountable, but must be considered when thinking about particle beam steering magnet qualit

Identifying Individual Discount Rates and Valuing Public Open Space with Stated Preference Models

An individual's rate of time preference is an important consideration for individuals deciding whether to support a public good since the benefits of a public good often come in the future. Our study finds individual discount rates from a contingent valuation method (CVM) question where the time frame of the payment schedule is varied across surveys. We find discount rates similar to the rates found in the recent revealed preference and experimental literature of around 30%. Our CVM question addresses the preservation of additional open space adjacent to a large regional park at the urban fringe of Portland, Oregon.Resource /Energy Economics and Policy, H43, Q51, Q15,

Center Vortex Model for the Infrared Sector of SU(3) Yang-Mills Theory - Vortex Free Energy

The vortex free energy is studied in the random vortex world-surface model of the infrared sector of SU(3) Yang-Mills theory. The free energy of a center vortex extending into two spatial directions, which is introduced into Yang-Mills configurations when acting with the 't Hooft loop operator, is verified to furnish an order parameter for the deconfinement phase transition. It is shown to exhibit a weak discontinuity at the critical temperature, corresponding to the weak first order character of the transition.Comment: 13 pages, 2 figures containing 3 eps file

Semi-Empirical Cepheid Period-Luminosity Relations in Sloan Magnitudes

In this paper we derive semi-empirical Cepheid period-luminosity (P-L) relations in the Sloan ugriz magnitudes by combining the observed BVI mean magnitudes from the Large Magellanic Cloud Cepheids (LMC) and theoretical bolometric corrections. We also constructed empirical gr band P-L relations, using the publicly available Johnson-Sloan photometric transformations, to be compared with our semi-empirical P-L relations. These two sets of P-L relations are consistent with each other.Comment: 4 pages, 2 tables and 2 figures, ApJ accepte