19,224 research outputs found
Government Transfer Payments and Strike Activity: Reforming Public Policy
[Excerpt] One of the most controversial labor policy issues is whether strikers should be eligible for government transfer payments, such as unemployment compensation, public assistance, and food stamps. The controversy often focuses on whether payment of such benefits to strikers increases the magnitude of strike activity. In this article, we argue that that is the wrong focus. The key issue is not whether strikers receive benefits, but who finances them. We contend that to the extent that the benefits are financed by the parties to the conflict (the employer and union), the transfers will not affect strike activity. This article extends our recent book on this topic, by briefly describing current and past policies, summarizing our argument for why financing is key, and presenting a proposal for reforming strike-related government transfers
Photon breeding mechanism in relativistic jets: astrophysical implications
Photon breeding in relativistic jets involves multiplication of high-energy
photons propagating from the jet to the external environment and back with the
conversion into electron-positron pairs. The exponential growth of the energy
density of these photons is a super-critical process powered by the bulk energy
of the jet. The efficient deceleration of the jet outer layers creates a
structured jet morphology with the fast spine and slow sheath. In initially
fast and high-power jets even the spine can be decelerated efficiently leading
to very high radiative efficiencies of conversion of the jet bulk energy into
radiation. The decelerating, structured jets have angular distribution of
radiation significantly broader than that predicted by a simple blob model with
a constant Lorentz factor. This reconciles the discrepancy between the high
Doppler factors determined by the fits to the spectra of TeV blazars and the
low apparent velocities observed at VLBI scales as well as the low jet Lorentz
factors required by the observed statistics and luminosity ratio of
Fanaroff-Riley I radio galaxies and BL Lac objects. Photon breeding produces a
population of high-energy leptons in agreement with the constraints on the
electron injection function required by spectral fits of the TeV blazars.
Relativistic pairs created outside the jet and emitting gamma-rays by inverse
Compton process might explain the relatively high level of the TeV emission
from the misaligned jet in the radio galaxies. The mechanism reproduces basic
spectral features observed in blazars including the blazar sequence (shift of
the spectral peaks towards lower energies with increasing luminosity). The
mechanism is very robust and can operate in various environments characterised
by the high photon density.Comment: 6 pages, 3 figures, to appear in the proceedings of the HEPRO
conference, September 24-28, 2007, Dublin, Irelan
Electronic dummy for acoustical testing
Electronic Dummy /ED/ used for acoustical testing represents the average male torso from the Xiphoid process upward and includes an acoustic replica of the human head. This head simulates natural flesh, and has an artificial voice and artificial ears that measure sound pressures at the eardrum or the entrance to the ear canal
Search for Non-Triggered Gamma Ray Bursts in the BATSE Continuous Records: Preliminary Results
We present preliminary results of an off-line search for non-triggered
gamma-ray bursts (GRBs) in the BATSE daily records for about 5.7 years of
observations. We found more GRB-like events than the yield of the similar
search of Kommers et al. (1998) and extended the Log N - log P distribution
down to 0.1 ph cm s. The indication of a turnover of the
log N - log P at a small P is not confirmed: the distribution is straight at
1.5 decades with the power law index -.6 and cannot be fitted with a standard
candle cosmological model.Comment: 4 pages, LaTeX, to appear in Proceedings "Gamma Ray Bursts in the
Afterglow Era", Rome, November 1998, A&AS, 199
Triton's surface age and impactor population revisited in light of Kuiper Belt fluxes: Evidence for small Kuiper Belt objects and recent geological activity
Neptune's largest satellite, Triton, is one of the most fascinating and
enigmatic bodies in the solar system. Among its numerous interesting traits,
Triton appears to have far fewer craters than would be expected if its surface
was primordial. Here we combine the best available crater count data for Triton
with improved estimates of impact rates by including the Kuiper Belt as a
source of impactors. We find that the population of impactors creating the
smallest observed craters on Triton must be sub-km in scale, and that this
small-impactor population can be best fit by a differential power-law size
index near -3. Such results provide interesting, indirect probes of the unseen
small body population of the Kuiper Belt. Based on the modern, Kuiper Belt and
Oort Cloud impactor flux estimates, we also recalculate estimated ages for
several regions of Triton's surface imaged by Voyager 2, and find that Triton
was probably active on a time scale no greater than 0.1-0.3 Gyr ago (indicating
Triton was still active after some 90% to 98% of the age of the solar system),
and perhaps even more recently. The time-averaged volumetric resurfacing rate
on Triton implied by these results, 0.01 km yr or more, is likely
second only to Io and Europa in the outer solar system, and is within an order
of magnitude of estimates for Venus and for the Earth's intraplate zones. This
finding indicates that Triton likely remains a highly geologically active world
at present, some 4.5 Gyr after its formation. We briefly speculate on how such
a situation might obtain.Comment: 14 pages (TeX), plus 2 postscript figures Stern & McKinnon, 2000, AJ,
in pres
Primordial nucleosynthesis as a probe of fundamental physics parameters
We analyze the effect of variation of fundamental couplings and mass scales
on primordial nucleosynthesis in a systematic way. The first step establishes
the response of primordial element abundances to the variation of a large
number of nuclear physics parameters, including nuclear binding energies. We
find a strong influence of the n-p mass difference (for the 4He abundance), of
the nucleon mass (for deuterium) and of A=3,4,7 binding energies (for 3He, 6Li
and 7Li). A second step relates the nuclear parameters to the parameters of the
Standard Model of particle physics. The deuterium, and, above all, 7Li
abundances depend strongly on the average light quark mass hat{m} \equiv
(m_u+m_d)/2. We calculate the behaviour of abundances when variations of
fundamental parameters obey relations arising from grand unification. We also
discuss the possibility of a substantial shift in the lithium abundance while
the deuterium and 4He abundances are only weakly affected.Comment: v2: 34 pages, 2 figures, typo in last GUT scenario corrected, added
discussion and graph of nonlinear behaviour in GUT scenarios, added short
section discussing binding of dineutron and 8Be, refs added, conclusions
unaltered. Accepted for publication, Phys. Rev.
The Amplitude in Generalized Chiral Perturbation Theory
The interaction is studied at one loop order in the framework of
Generalized Chiral Perturbation theoryComment: Compressed+ uuencoded Postscript file, 13pages, 6 figures to appear
in the 2nd ed. of the DAFNE Physics Handboo
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