7,532 research outputs found
Noncompact Gauge-Invariant Simulations of U(1), SU(2), and SU(3)
We have applied a new gauge-invariant, noncompact, Monte Carlo method to
simulate the , , and gauge theories on and
lattices. The Creutz ratios of the Wilson loops agree with the exact results
for for apart from a renormalization of the charge. The
and Creutz ratios robustly display quark confinement at and , respectively. At much weaker coupling, the and
Creutz ratios agree with perturbation theory after a renormalization of
the coupling constant. For the scaling window is near ,
and the relation between the string tension and our lattice QCD
parameter is .Comment: For U(1), we switched from beta = 2 / g^2 to beta = 1 / g^2; 3 pages;
latex and espcrc2.sty; one figure generated by PiCTeX; our contribution to
Lattice '9
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Lender Liability in the Consumer Credit Market
In many countries consumer credit legislation provides for the extension
of liability for product failure to the financial institution that
advances credit to the consumer. In particular, lender liability is imposed
on those credit grantors who closely operate with the supplier
of the good.
This paper provides a rationale for lender-responsibility in the consumer
credit market. It shows that, when judicial enforcement is inefficient
or there is risk of seller liquidation, lender-liability helps to
protect consumers who systematically underestimate the probability
of product failure and overestimate the extent to which they can obtain
compensation
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Optimism and lender liability in the consumer credit market
Credit purchases of consumer goods are commonly made upon terms governed by an agreement between the lender and the seller. This type of purchase is generally subject to a legal principle of joint responsibility under which the lender and the seller are jointly liable to the consumer for breach of the sale contract by the seller.
We study the rationale for this principle in situations where market failure arises because consumers underestimate the risk of product failure - for example due to seller misrepresentation - and it is difficult to enforce seller responsibility. We show that joint responsibility increases welfare and reduces the incentives of sellers to misrepresent the quality of their products
Decision rules and information provision: monitoring versus manipulation
The paper focuses on the organization of institutions designed to
resolve disputes between two parties, when some information is not
veri…able and decision makers may have vested preferences. It shows
that the choice of how much discretional power to grant to the decision
maker and who provides the information are intrinsically related. Direct
involvement of the interested parties in the supply of information
enhances monitoring over the decision maker, although at the cost of
higher manipulation. Thus, it is desirable when the decision maker is
granted high discretion. On the contrary, when the decision maker has
limited discretional power, information provision is better assigned to
an agent with no direct stake. The analysis helps to rationalize some
organizational arrangements that are commonly observed in the context
of judicial and antitrust decision-makin
Broad Line Radio Galaxies: Jet Contribution to the nuclear X-Ray Continuum
It is shown that, for Broad Line Radio Galaxies the strength of the
non-thermal beamed radiation, when present, is always smaller than the
accretion flow by a factor < 0.7 in the 2-10 keV band. The result has been
obtained using the procedure adopted for disentangling the Flat Spectrum Radio
Quasar 3C 273 (Grandi & Palumbo 2004). Although this implies a significantly
smaller non-thermal flux in Radio Galaxies when compared to Blazars, the jet
component, if present, could be important at very high energies and thus easily
detectable with GLAST.Comment: 12 pages including 2 figures (4 files), ApJ accepte
Relativistic Jets from X-ray binaries
In this review I summarise the status of observational research into
relativistic jets from X-ray binaries, highlighting four areas in particular:
(i) How relativistic are the jets ?, (ii) The disc : jet coupling, (iii) the
nature of the underlying flat spectral component, and (iv) the relation between
jets from black holes and those from neutron stars. I have attempted to discuss
the extent of our (limited) physical understanding, and to point the way
towards relevant new observational tests of the various phenomena.Comment: Review article, to be published in `Astrophysics and Cosmology : A
collection of critical thoughts', Springer Lecture Notes in Physic
Jets and outflows in Radio Galaxies: implications for AGN feedback
One of the main debated astrophysical problems is the role of the AGN
feedback in galaxy formation. It is known that massive black holes have a
profound effect on the formation and evolution of galaxies, but how black holes
and galaxies communicate is still an unsolved problem. For Radio Galaxies,
feedback studies have mainly focused on jet/cavity systems in the most massive
and X-ray luminous galaxy clusters. The recent high-resolution detection of
warm absorbers in some Broad Line Radio Galaxies allow us to investigate the
interplay between the nuclear engine and the surrounding medium from a
different perspective. We report on the detection of warm absorbers in two
Broad Line Radio Galaxies, 3C 382 and 3C 390.3, and discuss the physical and
energetic properties of the absorbing gas. Finally, we attempt a comparison
between radio-loud and radio-quiet outflows.Comment: To be published in the proceedings of High Energy Phenomena in
Relativistic Outflows III (HEPRO III, IJMPCS). 4 pages, 2 figure
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