Learning and location

In this paper we study whether learning from rivals affects within-market location decisions between competing firms. We show it does, using detailed locational data from two leading hamburger chains in the UK. Using four different tests, we demonstrate that alternative explanations - pre-emption and product differentiation - have less bite than between firm learning

Fast food - the early years: geography and the growth of a chain-store in the UK

We examine the development of UK outlets of a major fast food chain, from inauguration in 1974 until 1990, after which industry structure changed somewhat. The chain effectively introduced the counter-service burger concept. Locational spread across local authority district markets is explained by the characteristics of the areas where the outlets are sited. Of special interest is the effect of scale economies, measured by outlet numbers in neighboring districts. Both first and second entry are examined. We find that the hazard of first entry is positively influenced by market size and population density and negatively by distance from company headquarters

Market structure and entry in fast food

One of the phenomena of the twentieth century, chainstores, are remarkably little studied by economists. Amongst open questions are the following: What factors influence the pattern of their openings? Does the spread of one constrain others having broadly the same retail offer? Do they locate close to competitors? To answer such questions, one must examine a time path of development- put simply one must observe actual entry. This is precisely what is done in a series of papers (Toivanen and Waterson, 2000; 2001; Sault, Toivanen and Waterson -hereafter STW, 2002; forthcoming) we are working on concerning the spread of restaurant outlets in the UK. This paper sketches the main elements of our program, then examines a particular issue, the micro-geography of location, in detail

Collective vibrational states with fast iterative QRPA method

An iterative method we previously proposed to compute nuclear strength functions is developed to allow it to accurately calculate properties of individual nuclear states. The approach is based on the quasi-particle-random-phase approximation (QRPA) and uses an iterative non-hermitian Arnoldi diagonalization method where the QRPA matrix does not have to be explicitly calculated and stored. The method gives substantial advantages over conventional QRPA calculations with regards to the computational cost. The method is used to calculate excitation energies and decay rates of the lowest lying 2+ and 3- states in Pb, Sn, Ni and Ca isotopes using three different Skyrme interactions and a separable gaussian pairing force.Comment: 10 pages, 11 figure

Study of odd-mass N=82 isotones with realistic effective interactions

The microscopic quasiparticle-phonon model, MQPM, is used to study the energy spectra of the odd $Z=53 - 63$, N=82 isotones. The results are compared with experimental data, with the extreme quasiparticle-phonon limit and with the results of an unrestricted $2s1d0g_{7/2}0h_{11/2}$ shell model (SM) calculation. The interaction used in these calculations is a realistic two-body G-matrix interaction derived from modern meson-exchange potential models for the nucleon-nucleon interaction. For the shell model all the two-body matrix elements are renormalized by the $\hat{Q}$-box method whereas for the MQPM the effective interaction is defined by the G-matrix.Comment: Elsevier latex style espart, 26 pages, submitted to Nuclear Physics

Self Consistent and Renormalized particle-particle RPA in a Schematic Model

The dynamical effects of ground state correlations for excitation energies and transition strengths near the superfluid phase transition are studied in the soluble two level pairing model, in the context of the particle-particle self consistent Random Phase Approximation (SCRPA). Exact results are well reproduced across the transition region, beyond the collapse of the standard particle-particle Random Phase Approximation. The effects of two-body correlation in the SCRPA are displayed explicitly.Comment: 11 pages, revtex, 3ps figures, to appear in Phys. Rev.

A Substorm Onset Observed by the POLAR Spacecraft in Conjunction with the IMAGE Chain

We present observations of the Polar spacecraft of magnetospheric substorm signatures in the plasma sheet midway along auroral field lines between the ionosphere and the equatorial plasma sheet. An isolated substorm on October 17, 1997, is studied in detail. The onset time at 2040:42 UT was defined to be almost simultaneous (within 20 sec) on the ground and at Polar altitude (~ 4RE. At Polar, the onset was manifested as strong magnetic field variations and plasma flow bursts with amplitudes exceeding 20 nT and 100 km/s, respectively. Bursts of parallel Poynting flux of ~ 0.5 ergs/cm2 were related to these variations, and they were predominantly directed toward the ionosphere. In addition, a sequence of weak magnetic field variations and flow bursts were observes at Polar ~ 10 min before the onset. Associated with this, a weak westward electrojet was observed on the ground. We discuss the importance of these observations in the physics of substorm onset