Accelerators Beyond The Tevatron?

Following the successful operation of the Fermilab superconducting accelerator three new higher energy accelerators were planned. They were the UNK in the Soviet Union, the LHC in Europe, and the SSC in the United States. All were expected to start producing physics about 1995. They did not. Why?Comment: Presented at SIMPOSIO CINVESTAV-UNAM In Memoriam AUGUSTO GARCIA (1942-2009

Application of Bootstrap Methods in Investigation of Size of the Granger Causality Test for Integrated VAR Systems

This paper examines the size performance of the Toda-Yamamoto test for Granger causality in the case of trivariate integrated and cointegrated VAR systems. The standard asymptotic distribution theory and the residual-based bootstrap approach are applied. A variety of types of distribution of error term is considered. The impact of misspecification of initial parameters as well as the influence of an increase in sample size and number of bootstrap replications on size performance of Toda-Yamamoto test statistics is also examined. The results of the conducted simulation study confirm that standard asymptotic distribution theory may often cause significant over-rejection. Application of bootstrap methods usually leads to improvement of size performance of the Toda-Yamamoto test. However, in some cases the considered bootstrap method also leads to serious size distortion and performs worse than the traditional approach based on ÷2 distribution.bootstrap methods, simulation, Granger causality, bootstrap methods, simulation, Granger causality, VAR models models

Do R&D Subsidies Stimulate or Displace Private R&D? Evidence from Israel

In evaluating the effect of an R&D subsidy we need to know what the subsidized firm would have spent on R&D had it not received the subsidy. Using data on Israeli manufacturing firms in the 1990s we find evidence suggesting that the R&D subsidies granted by the Ministry of Industry and Trade stimulated long-run company-financed R&D expenditures: their long-run elasticity with respect to R&D subsidies is 0.22. At the means of the data, an extra dollar of R&D subsidies increases long-run company-financed R&D expenditures by 41 cents (total R&D expenditures increase by 1.41 dollars). Although the magnitude of this effect is large enough to justify the existence of the subsidy program, it is lower than expected given the dollar-by-dollar matching upon which most subsidized projects are based. This less than full' effect reflects two forces: first, subsidies are sometimes granted to projects that would have been undertaken even in the absence of the subsidy and, second, firms adjust their portfolio of R&D projects-closing or slowing down non-subsidized projects-after the subsidy is received.

Existence and Persistence of Price Dispersion: an Empirical Analysis

Using a unique data set on store-level monthly prices of four homogenous products sold in Israel, I study the existence and characteristics of the dispersion of prices across stores, as well as its persistence over time. I find that price dispersion prevails even after controlling for observed and unobserved product heterogeneity. Moreover, intra-distribution mobility is significant: stores move up and down the cross-sectional price distribution. Thus, consumers cannot learn about stores that consistently post low prices. As a consequence, price dispersion does not disappear and persists over time as predicted by Varian's (1980) model of sales.

Non-Contact Friction for Ion-Surface Interactions

Non-contact friction forces are exerted on physical systems through dissipative processes, when the two systems are not in physical contact with each other, or, in quantum mechanical terms, when the overlap of their wave functions is negligible. Non-contact friction is mediated by the exchange of virtual quanta, with the additional requirement that the scattering process needs to have an inelastic component. For finite-temperature ion-surface interactions, the friction is essentially caused by Ohmic resistance due to the motion of the image charge moving in a dielectric material. A conceivable experiment is difficult because the friction force needs to be isolated from the interaction with the image charge, which significantly distorts the ion's flight path. We propose an experimental setup which is designed to minimize the influence of the image charge interaction though a compensation mechanism, and evaluate the energy loss due to non-contact friction for helium ions (He+) interacting with gold, vanadium, titanium and graphite surfaces. Interactions with the infinite series of mirror charges in the plates are summed in terms of the logarithmic derivatives of the Gamma function, and of the Hurwitz zeta function.Comment: 9 pages; ReVTeX; accepted for publication in Eur.Phys.J.

Model of charge and magnetic order formation in itinerant electron systems

We propose a simple model of charge and/or magnetic order formation in systems containing both localized and itinerant electrons coupled by the on-site, spin-dependent interaction that represents Coulomb repulsion and Hund's rule (a generalized Falicov-Kimball model). Ground state properties of the model are analyzed on the square lattice on a basis of the phase diagrams that have been constructed rigorously, but in a restricted configurational space. For intermediate values of the coupling constants there are considerable ranges of itinerant electron densities where phases with complex charge and magnetic structures of the localized electrons have lower energy than the simplest antiferro- and ferromagnetic ones. A strong tendency towards the antiferromagnetic coupling between spins of localized electrons has been observed close to half-filling for any density of localized electrons, including situations where the magnetic ions are diluted. For small band fillings the ferromagnetic coupling between localized spins is predominant.Comment: 13 pages, 5 figure

Staggering and Synchronization in Price-Setting: Evidence from Multipro-duct Firms

Most of the theoretical literature on price-setting behavior deals with the special case in which only a single price is changed. At the retail-store level, at least, where dozens of products are sold by a single price-setter, price-setting policies are not formulated for individual products. This feature of economic behavior raises a host of questions whose answers carry interesting implications. Are price setters staggered in the timing of price changes? Are price changes of different products synchronized within the store? If so, is this a result of aggregate shocks or of the presence of a store- specific component in the cost of adjusting prices? Can observed small changes in prices be rationalized by a menu cost model? We exploit the multiproduct dimension of the dataset on prices used in Lach and Tsiddon (1992a) to explore several of these and other issues. To the best of our knowledge this is the first empirical work on this subject.