12,783 research outputs found
Literacy Practices and Schooling: A Case Study from Mozambique
A novel approach to the assessment of literacy is used to tackle the issue of effectiveness of years of schooling. The dichotomy inherent in the literacy rate is rejected in favor of a " practice-based" approach, which considers literacy as a multifaceted phenomenon as advocated in anthropological and economic research. Primary data collected in the poorest region in Mozambique suggest that years of schooling have a differentiated impact on acquired literacy practices of adults. Results that are robust to different specifications are reported. © 2011 Elsevier Ltd
Quantized Maxwell Theory in a Conformally Invariant Gauge
Maxwell theory can be studied in a gauge which is invariant under conformal
rescalings of the metric, and first proposed by Eastwood and Singer. This paper
studies the corresponding quantization in flat Euclidean 4-space. The resulting
ghost operator is a fourth-order elliptic operator, while the operator P on
perturbations of the potential is a sixth-order elliptic operator. The operator
P may be reduced to a second-order non-minimal operator if a dimensionless
gauge parameter tends to infinity. Gauge-invariant boundary conditions are
obtained by setting to zero at the boundary the whole set of perturbations of
the potential, jointly with ghost perturbations and their normal derivative.
This is made possible by the fourth-order nature of the ghost operator. An
analytic representation of the ghost basis functions is also obtained.Comment: 8 pages, plain Tex. In this revised version, the calculation of ghost
basis functions has been amended, and the presentation has been improve
Spectral asymptotics of Euclidean quantum gravity with diff-invariant boundary conditions
A general method is known to exist for studying Abelian and non-Abelian gauge
theories, as well as Euclidean quantum gravity, at one-loop level on manifolds
with boundary. In the latter case, boundary conditions on metric perturbations
h can be chosen to be completely invariant under infinitesimal diffeomorphisms,
to preserve the invariance group of the theory and BRST symmetry. In the de
Donder gauge, however, the resulting boundary-value problem for the Laplace
type operator acting on h is known to be self-adjoint but not strongly
elliptic. The latter is a technical condition ensuring that a unique smooth
solution of the boundary-value problem exists, which implies, in turn, that the
global heat-kernel asymptotics yielding one-loop divergences and one-loop
effective action actually exists. The present paper shows that, on the
Euclidean four-ball, only the scalar part of perturbative modes for quantum
gravity are affected by the lack of strong ellipticity. Further evidence for
lack of strong ellipticity, from an analytic point of view, is therefore
obtained. Interestingly, three sectors of the scalar-perturbation problem
remain elliptic, while lack of strong ellipticity is confined to the remaining
fourth sector. The integral representation of the resulting zeta-function
asymptotics is also obtained; this remains regular at the origin by virtue of a
spectral identity here obtained for the first time.Comment: 25 pages, Revtex-4. Misprints in Eqs. (5.11), (5.14), (5.16) have
been correcte
Non-stationary inflation and panel estimates of the n ew Keynesian Phillips curve for Australia
This paper uses a recent panel method of Russell and Banerjee (2008) to estimate the new Keynesian Phillips curve for Australia. Our estimates show that while the hybrid new Keynesian Phillips curve and backward looking conventional Phillips curve are well determined, estimates of the Phillips curve with the pure forward looking expectations are unsatisfactory.Panel data estimates, new Keynesian Phillips curve, Australia and Unit roots in the rate of inflation.
The dynamics of French public debt: Paths for fiscal consolidations
We analyze possible targets for the French debt-to-GDP ratio with a small model. The role of the US and German GDP growth, prices of raw materials, ECB monetary policy, and domestic policy is analyzed in the debt dynamics. We find that external conditions, together with policies to stimulate growth and to generate a government surplus, play a fundamental role in the French fiscal consolidation.Debt to GDP Ratio, French Economy, International Factors
Euclidean Maxwell Theory in the Presence of Boundaries. II
Zeta-function regularization is applied to complete a recent analysis of the
quantized electromagnetic field in the presence of boundaries. The quantum
theory is studied by setting to zero on the boundary the magnetic field, the
gauge-averaging functional and hence the Faddeev-Popov ghost field. Electric
boundary conditions are also studied. On considering two gauge functionals
which involve covariant derivatives of the 4-vector potential, a series of
detailed calculations shows that, in the case of flat Euclidean 4-space bounded
by two concentric 3-spheres, one-loop quantum amplitudes are gauge independent
and their mode-by-mode evaluation agrees with the covariant formulae for such
amplitudes and coincides for magnetic or electric boundary conditions. By
contrast, if a single 3-sphere boundary is studied, one finds some
inconsistencies, i.e. gauge dependence of the amplitudes.Comment: 24 pages, plain-tex, recently appearing in Classical and Quantum
Gravity, volume 11, pages 2939-2950, December 1994. The authors apologize for
the delay in circulating the file, due to technical problems now fixe
The dynamics of Spanish public debt and sustainable paths for fiscal consolidation
This paper analyses possible patterns for the Spain debt-to-GDP ratio with a small macroeconomic model. The role of international macroeconomic variables (such as the US and French GDP growth rates, prices of raw materials, ECB monetary policy stance) and domestic policy instruments is analyzed in the debt dynamics. We find that external conditions, together with policies aimed to stimulate the growth and fulfilling Maastricht restrictions on deficit, play a fundamental role for fiscal consolidation in Spain and help to reach a sustainable pattern.Debt to GDP Ratio, Spain Economy, International Factors, SUR
New Developments in the Spectral Asymptotics of Quantum Gravity
A vanishing one-loop wave function of the Universe in the limit of small
three-geometry is found, on imposing diffeomorphism-invariant boundary
conditions on the Euclidean 4-ball in the de Donder gauge. This result suggests
a quantum avoidance of the cosmological singularity driven by full
diffeomorphism invariance of the boundary-value problem for one-loop quantum
theory. All of this is made possible by a peculiar spectral cancellation on the
Euclidean 4-ball, here derived and discussed.Comment: 7 pages, latex file. Paper prepared for the Conference "QFEXT05:
Quantum Field Theory Under the Influence of External Conditions", Barcelona,
September 5 - September 9, 2005. In the final version, the presentation has
been further improved, and yet other References have been adde
Quantum Effects in Friedmann-Robertson-Walker Cosmologies
Electrodynamics for self-interacting scalar fields in spatially flat
Friedmann-Robertson-Walker space-times is studied. The corresponding one-loop
field equation for the expectation value of the complex scalar field in the
conformal vacuum is derived. For exponentially expanding universes, the
equations for the Bogoliubov coefficients describing the coupling of the scalar
field to gravity are solved numerically. They yield a non-local correction to
the Coleman-Weinberg effective potential which does not modify the pattern of
minima found in static de Sitter space. Such a correction contains a
dissipative term which, accounting for the decay of the classical configuration
in scalar field quanta, may be relevant for the reheating stage. The physical
meaning of the non-local term in the semiclassical field equation is
investigated by evaluating this contribution for various background field
configurations.Comment: 17 pages, plain TeX + 5 uuencoded figure
One-Loop Effective Action for Euclidean Maxwell Theory on Manifolds with Boundary
This paper studies the one-loop effective action for Euclidean Maxwell theory
about flat four-space bounded by one three-sphere, or two concentric
three-spheres. The analysis relies on Faddeev-Popov formalism and
-function regularization, and the Lorentz gauge-averaging term is used
with magnetic boundary conditions. The contributions of transverse,
longitudinal and normal modes of the electromagnetic potential, jointly with
ghost modes, are derived in detail. The most difficult part of the analysis
consists in the eigenvalue condition given by the determinant of a
or matrix for longitudinal and normal modes. It is shown that the
former splits into a sum of Dirichlet and Robin contributions, plus a simpler
term. This is the quantum cosmological case. In the latter case, however, when
magnetic boundary conditions are imposed on two bounding three-spheres, the
determinant is more involved. Nevertheless, it is evaluated explicitly as well.
The whole analysis provides the building block for studying the one-loop
effective action in covariant gauges, on manifolds with boundary. The final
result differs from the value obtained when only transverse modes are
quantized, or when noncovariant gauges are used.Comment: 25 pages, Revte
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