Non-competes, business dynamism, and concentration: Evidence from a Florida case study

Most research on non-competes has focused on employees; here we study how non-competes affect firm location choice, growth, and consequent regional concentration, using Florida's 1996 legislative change that eased restrictions on their enforcement. Difference-in-differences models show that following the change, establishments of large firms were more likely to enter Florida; they also created a greater proportion of jobs and increased their share of employment in the state. Entrepreneurs or establishments of small firms, in contrast, were less likely to enter Florida following the law change; they also created a smaller proportion of new jobs and decreased their share of employment. Consistent with these location and job creation dynamics, regional business concentration increased following the law change in Florida. Nationwide cross-sections demonstrate consistent correlations between state-level non-compete enforcement and the location, employment, and concentration dynamics illustrated in Florida

Results of the 1977 southern California pismo clam survey

A Pismo clam, Tivela stultorum, survey was conducted in January 1977 on selected southern California beaches. Effort and catch information was collected through clammer interviews. Estimates for the two day survey were 1,596 clammers spending 2,506 hours to take 6,139 clams. Comparisons were made between the 1977 survey results and previous surveys. Clams were collected for length and age studies. Compliance to the 4.5-inch (114.3 mm) minimum size limit appeared to be good. (15pp.

Foraging activity by the southern brown bandicoot (Isoodon obesulus) as a mechanism for soil turnover

Mammals that forage for food by biopedturbation can alter the biotic and abiotic characteristics of their habitat, influencing ecosystem structure and function. Bandicoots, bilbies, bettongs and potoroos are the primary digging marsupials in Australia, although most of these species have declined throughout their range. This study used a snapshot approach to estimate the soil turnover capacity of the southern brown bandicoot (Isoodon obesulus, Shaw 1797), a persisting digging Australian marsupial, at Yalgorup National Park, Western Australia. The number of southern brown bandicoots was estimated using mark-recapture techniques. To provide an index of digging activity per animal, we quantified the number of new foraging pits and bandicoot nose pokes across 18 plots within the same area. The amount of soil displaced and physical structure of foraging pits were examined from moulds of 47 fresh foraging pits. We estimated that an individual southern brown bandicoot could create ∼45 foraging pits per day, displacing ∼10.74kg of soil, which extrapolates to ∼3.9 tonnes of soil each year. The digging activities of the southern brown bandicoots are likely to be a critical component of soil ecosystem processe

Nonequilibrium Dynamics of Charged Particles in an Electromagnetic Field: Causal and Stable Dynamics from 1/c Expansion of QED

We derive from a microscopic Hamiltonian a set of stochastic equations of motion for a system of spinless charged particles in an electromagnetic (EM) field based on a consistent application of a dimensionful 1/c expansion of quantum electrodynamics (QED). All relativistic corrections up to order 1/c^3 are captured by the dynamics, which includes electrostatic interactions (Coulomb), magnetostatic backreaction (Biot-Savart), dissipative backreaction (Abraham-Lorentz) and quantum field fluctuations at zero and finite temperatures. With self-consistent backreaction of the EM field included we show that this approach yields causal and runaway-free equations of motion, provides new insights into charged particle backreaction, and naturally leads to equations consistent with the (classical) Darwin Hamiltonian and has quantum operator ordering consistent with the Breit Hamiltonian. To order 1/c^3 the approach leads to a nonstandard mass renormalization which is associated with magnetostatic self-interactions, and no cutoff is required to prevent runaways. Our new results also show that the pathologies of the standard Abraham-Lorentz equations can be seen as a consequence of applying an inconsistent (i.e. incomplete, mixed-order) expansion in 1/c, if, from the start, the analysis is viewed as generating a low-energy effective theory rather than an exact solution. Finally, we show that the 1/c expansion within a Hamiltonian framework yields well-behaved noise and dissipation, in addition to the multiple-particle interactions.Comment: 17 pages, 2 figure

Unimolecular reaction rates in solution and in the isolated molecule: Comparison of diphenyl butadiene nonradiative decay in solutions and supersonic jets

The recent study of diphenyl butadiene (DPB) in supersonic jets and in solution by Shepanski et al.(1) and by Courtney and Felming(2), respectively, provides an opportunity to compare the isomerization rates measured in the isolated molecule (jet) with those measured at very low viscosity in solution. These comparisons should shed light on the vibrational energy flows between “optical” and “reactive” modes in the isolated molecule and on the connection between activated, friction dependent, models of barrier crossing in solution,(3-5) and statistical RRK (or RRKM) theories of gas phase unimolecular reactions(6)

Series-hybrid bearing - An approach to extending bearing fatigue life at high speeds

Fluid film bearing of hybrid device consists of orifice compensated annular thrust bearing and self-acting journal bearing. In series hybrid bearing, both ball bearing and annular thrust bearing carry full system thrust load, but two bearings share speed. Operation of system is stable and automatically fail-safe