38,852 research outputs found
The Incidence of Reserve Requirements in Brazil: Do Bank Stockholders Share the Burden?
There is consensus in the economic literature that the reserve requirements are a tax levied upon financial intermediation, yet the incidence of the tax remains controversial. In this paper, we test whether changes in reserve requirements in Brazil impact the stock returns of the financial system distinctly from the rest of the economy. We find evidence that Brazilian bank stock returns were affected by changes in reserve requirements on both time deposits and transaction accounts, which implies that the tax burden of required reserves was not fully passed through to banks' borrowers or clients. Stock returns of non-financial firms were also affected by these changes, suggesting that in some cases, reserve requirements on time deposits and transaction accounts served as a non-neutral instrument of monetary or fiscal policy in Brazil.
Quantum statistical correlations in thermal field theories: boundary effective theory
We show that the one-loop effective action at finite temperature for a scalar
field with quartic interaction has the same renormalized expression as at zero
temperature if written in terms of a certain classical field , and if
we trade free propagators at zero temperature for their finite-temperature
counterparts. The result follows if we write the partition function as an
integral over field eigenstates (boundary fields) of the density matrix element
in the functional Schr\"{o}dinger field-representation, and perform a
semiclassical expansion in two steps: first, we integrate around the
saddle-point for fixed boundary fields, which is the classical field ,
a functional of the boundary fields; then, we perform a saddle-point
integration over the boundary fields, whose correlations characterize the
thermal properties of the system. This procedure provides a
dimensionally-reduced effective theory for the thermal system. We calculate the
two-point correlation as an example.Comment: 13 pages, 1 figur
Continuity properties of a factor of Markov chains
Starting from a Markov chain with a finite alphabet, we consider the chain
obtained when all but one symbol are undistinguishable for the practitioner. We
study necessary and sufficient conditions for this chain to have continuous
transition probabilities with respect to the past
Charm and longitudinal structure functions with the Kharzeev-Levin-Nardi model
We use the Kharzeev-Levin-Nardi model of the low gluon distributions to
fit recent HERA data on charm and longitudinal structure functions. Having
checked that this model gives a good description of the data, we use it to
predict and to be measured in a future electron-ion collider. The
results interpolate between those obtained with the de Florian-Sassot and
Eskola-Paukkunen-Salgado nuclear gluon distributions. The conclusion of this
exercise is that the KLN model, simple as it is, may still be used as an
auxiliary tool to make estimates both for heavy ion and electron-ion
collisions.Comment: 6 pages, 7 figure
Dimensional reduction of the CPT-even electromagnetic sector of the Standard Model Extension
The CPT-even abelian gauge sector of the Standard Model Extension is
represented by the Maxwell term supplemented by
, where the
Lorentz-violating background tensor, , possesses
the symmetries of the Riemann tensor. In the present work, we examine the
planar version of this theory, obtained by means of a typical dimensional
reduction procedure to dimensions. The resulting planar electrodynamics
is composed of a gauge sector containing six Lorentz-violating coefficients, a
scalar field endowed with a noncanonical kinetic term, and a coupling term that
links the scalar and gauge sectors. The dispersion relation is exactly
determined, revealing that the six parameters related to the pure
electromagnetic sector do not yield birefringence at any order. In this model,
the birefringence may appear only as a second order effect associated with the
coupling tensor linking the gauge and scalar sectors.The equations of motion
are written and solved in the stationary regime. The Lorentz-violating
parameters do not alter the asymptotic behavior of the fields but induce an
angular dependence not observed in the Maxwell planar theory.Comment: 13 pages, revtex style, no figures, to appear in Physical Review
D(2011
Particle Learning for General Mixtures
This paper develops particle learning (PL) methods for the estimation of general mixture models. The approach is distinguished from alternative particle filtering methods in two major ways. First, each iteration begins by resampling particles according to posterior predictive probability, leading to a more efficient set for propagation. Second, each particle tracks only the "essential state vector" thus leading to reduced dimensional inference. In addition, we describe how the approach will apply to more general mixture models of current interest in the literature; it is hoped that this will inspire a greater number of researchers to adopt sequential Monte Carlo methods for fitting their sophisticated mixture based models. Finally, we show that PL leads to straight forward tools for marginal likelihood calculation and posterior cluster allocation.Business Administratio
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