2,484 research outputs found
New Market Power Models and Sex Differences in Pay
In the context of certain general equilibrium search models, it is possible to infer the elasticity of labor supply to the firm from the elasticity of the quit rate with respect to the wage. We use this framework to estimate the elasticity of labor supply for men and women workers at a chain of grocery stores operating in the southwestern United States, identifying separation elasticities from differences in wages and separation rates across different job titles within the firm. We estimate elasticities of labor supply to the firm of about 2.7 for men and about 1.5 for women, suggesting significant wage-setting power for the firm. Since women have lower elasticities of labor supply to the firm, a Robinson-style monopsony model might explain lower relative pay of women in the grocery industry. The wage gaps we observe among workers in US retail grocery stores are close to what the monopsony model predicts for the elasticities we have estimated.monopsony papers, labor supply, grocery stores, elasticity
Estimating the Firm's Labor Supply Curve in a "New Monopsony" Framework: School Teachers in Missouri
In the context of certain dynamic models, it is possible to infer the elasticity of labor supply to the firm from the elasticity of the quit rate with respect to the wage. Using this property, we estimate the average labor supply elasticity to public school districts in Missouri. We take advantage of the plausibly exogenous variation in pre-negotiated district salary schedules to instrument for actual salary. Instrumental variables estimates lead to a labor supply elasticity estimate of about 3.7, suggesting the presence of significant market power for school districts, especially over more experienced teachers. The presence of monopsony power in this labor market may be partially explained by institutional features of the teacher labor market.labor monopsony, teachers
Modern Models of Monopsony in Labor Markets: A Brief Survey
This brief survey contains a review of several new empirical papers that attempt to measure the extent of monopsony in labor markets. As noted originally by Joan Robinson, monopsonistic exploitation represents the gap between the value of a worker's marginal product and the worker's wage, and it represents both a distortion in the allocation of resources and an income transfer away from workers. The evidence surveyed from a fairly broad range of labor markets suggests that monopsony may be far more pervasive than is sometimes suggested.imperfect labor markets, monopsony
VLBI for Gravity Probe B. VII. The Evolution of the Radio Structure of IM Pegasi
We present measurements of the total radio flux density as well as
very-long-baseline interferometry (VLBI) images of the star, IM Pegasi, which
was used as the guide star for the NASA/Stanford relativity mission Gravity
Probe B. We obtained flux densities and images from 35 sessions of observations
at 8.4 GHz (wavelength = 3.6 cm) between 1997 January and 2005 July. The
observations were accurately phase-referenced to several extragalactic
reference sources, and we present the images in a star-centered frame, aligned
by the position of the star as derived from our fits to its orbital motion,
parallax, and proper motion. Both the flux density and the morphology of IM Peg
are variable. For most sessions, the emission region has a single-peaked
structure, but 25% of the time, we observed a two-peaked (and on one occasion
perhaps a three-peaked) structure. On average, the emission region is elongated
by 1.4 +- 0.4 mas (FWHM), with the average direction of elongation being close
to that of the sky projection of the orbit normal. The average length of the
emission region is approximately equal to the diameter of the primary star. No
significant correlation with the orbital phase is found for either the flux
density or the direction of elongation, and no preference for any particular
longitude on the star is shown by the emission region.Comment: Accepted for publication in the Astrophysical Journal Supplement
Serie
A device for testing the electronic and mechanical properties of conducting polymers with electron paramagnetic resonance spectroscopy
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.Includes bibliographical references (leaf 35).Conducting polymers have the potential to serve the technical and commercial communities with novel actuators, sensors, and biomimetic devices. The conjugated structures of these polymers and the addition of dopants enable conduction. [1] One current goal in the conducting polymer field is to observe and understand the events by which these polymers carryout their active mechanical functions (contraction and expansion) upon the application of a potential. This thesis presents the design and a prototype of a new device for investigating the relationship between the mechanical and electronic properties of conducting polymers with EPR Spectroscopy. The performance of the testing device was explored with a controlled experiment. The results of this experiment suggest that the response of conducting polymer actuators to mechanical inputs can be examined with EPR Spectroscopy.by Nicholas R. Powley.S.B
Discovery of an Energetic Pulsar Associated with SNR G76.9+1.0
We report the discovery of PSR J2022+3842, a 24 ms radio and X-ray pulsar in
the supernova remnant G76.9+1.0, in observations with the Chandra X-ray
telescope, the Robert C. Byrd Green Bank Radio Telescope, and the Rossi X-ray
Timing Explorer (RXTE). The pulsar's spin-down rate implies a rotation-powered
luminosity Edot = 1.2 x 10^{38} erg/s, a surface dipole magnetic field strength
B_s = 1.0 x 10^{12} G, and a characteristic age of 8.9 kyr. PSR J2022+3842 is
thus the second-most energetic Galactic pulsar known, after the Crab, as well
as the most rapidly-rotating young, radio-bright pulsar known. The radio
pulsations are highly dispersed and broadened by interstellar scattering, and
we find that a large (delta-f / f ~= 1.9 x 10^{-6}) spin glitch must have
occurred between our discovery and confirmation observations. The X-ray pulses
are narrow (0.06 cycles FWHM) and visible up to 20 keV, consistent with
magnetospheric emission from a rotation-powered pulsar. The Chandra X-ray image
identifies the pulsar with a hard, unresolved source at the midpoint of the
double-lobed radio morphology of SNR G76.9+1.0 and embedded within faint,
compact X-ray nebulosity. The spatial relationship of the X-ray and radio
emissions is remarkably similar to extended structure seen around the Vela
pulsar. The combined Chandra and RXTE pulsar spectrum is well-fitted by an
absorbed power-law model with column density N_H = (1.7\pm0.3) x 10^{22}
cm^{-2} and photon index Gamma = 1.0\pm0.2; it implies that the Chandra
point-source flux is virtually 100% pulsed. For a distance of 10 kpc, the X-ray
luminosity of PSR J2022+3842 is L_X(2-10 keV) = 7.0 x 10^{33} erg s^{-1}.
Despite being extraordinarily energetic, PSR J2022+3842 lacks a bright X-ray
wind nebula and has an unusually low conversion efficiency of spin-down power
to X-ray luminosity, L_X/Edot = 5.9 x 10^{-5}.Comment: 8 pages in emulateapj format. Minor changes (including a shortened
abstract) to reflect the version accepted for publicatio
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