55,310 research outputs found
Inflation and Budget Deficit: What is the Relationship in Portugal?
The main causes of Portuguese inflation, based on annual data from 1954 to 1995, using the Johansen method, allows us to conclude that variation in Portuguese inflation is determined essentially by foreign inflation and by variation in the effective exchange rate of the Portuguese Escudo (PTE). In the long-term, the relationship between inflation rate and the growth rate of unit labour costs is almost unitary. However, the response of inflation change to the equilibrium error between inflation rate and changes in unit labour costs is slow and almost insignificant, while the response of unit labour costs to this disequilibrium is fast and significant, what suggests that the direction of causality is much more evident from the inflation rate on unit labour costs, than the reverse. The budget deficit as a percentage of GDP, are not significant in the short-term, in relation to variation in inflation as a dependent variable. However, it is significant in the relation to unit labour costs as a dependent variable, so we can have an indirect positive relation between inflation and lagged budget deficit.Inflation, Budget Deficit, Unit Roots, and Cointegration
Stability of Closed Timelike Geodesics
The existence and stability under linear perturbations of closed timelike
geodesics (CTGs) in Bonnor-Ward spacetime is studied in some detail. Regions
where the CTG exist and are linearly stable are exhibited.Comment: 5 pages, REvTex, discussion added. PLA, in pres
Reliability of the optimized perturbation theory in the 0-dimensional scalar field model
We address the reliability of the Optimized Perturbation Theory (OPT) in the
context of the 0-dimensional scalar field model. The effective
potential, the self-energy and the 1PI four-point Green's function for the
model are computed using different optimization schemes and the results
contrasted to the exact results for the model. Our results are also compared to
those obtained with the -expansion and with those from ordinary
perturbation theory. The OPT results are shown to be stable even at large
couplings and to have better convergence properties than the ones produced in
the -expansion. It is also shown that the principle of minimal sensitive
optimization procedure used in conjunction with the OPT method tends to always
produce better results, in particular when applied directly to the self-energy.Comment: 38 pages, 13 figures, v2 Physica A versio
Modulation of near-field heat transfer between two gratings
We present a theoretical study of near-field heat transfer between two
uniaxial anisotropic planar structures. We investigate how the distance and
relative orientation (with respect to their optical axes) between the objects
affect the heat flux. In particular, we show that by changing the angle between
the optical axes it is possible in certain cases to modulate the net heat flux
up to 90% at room temperature, and discuss possible applications of such a
strong effect
Changing the University System Management: a study of the Italian scenario
Over recent years, the Italian University System has been handling a phase of deep
changes, which have had significant impact on its mission and on the way it operates.
The most important of these changes have been to the organisation of universities, their
recruitment procedures and in terms of improvements to the quality and efficiency of
the university system itself. In this perspective, the objective of this research was to carry
out a critical analysis of the process of change, with special reference to improving
efficiency by making the transition from cash-based accounting to accrual accounting. In
order to achieve this objective, the starting point was the legislation of reference that
sets out the terms for the move to financial accrual accounting. A comparative analysis
was then carried out at an international level, with the purpose of highlighting the
strengths and weaknesses identified during the implementation of these new
procedures within the public field. This was followed by an analysis of the details of the
theory defining the accounting principles to be used in the process of preparing
university’s financial statements. Finally, the study identified the main critical points
relating to implementation of the new accounting system, offering, at the same time,
several thoughts concerning possible subsequent analyses on this topic
Extremum-entropy-based Heisenberg-like uncertainty relations
In this work we use the extremization method of various information-theoretic
measures (Fisher information, Shannon entropy, Tsallis entropy) for
-dimensional quantum systems, which complementary describe the spreading of
the quantum states of natural systems. Under some given constraints, usually
one or two radial expectation values, this variational method allows us to
determine an extremum-entropy distribution, which is the \textit{least-biased}
one to characterize the state among all those compatible with the known data.
Then we use it, together with the spin-dependent uncertainty-like relations of
Daubechies-Thakkar type, as a tool to obtain relationships between the position
and momentum radial expectation values of the type , for -dimensional systems of fermions with spin . The
resulting uncertainty-like products, which take into account both spatial and
spin degrees of freedom of the fermionic constituents of the system, are shown
to often improve the best corresponding relationships existing in the
literature.Comment: Accepted for publication in Journal of Physics
Cosmological solutions in generalized hybrid metric-Palatini gravity
We construct exact solutions representing a
Friedmann-Lema\^itre-Robsertson-Walker (FLRW) universe in a generalized hybrid
metric-Palatini theory. By writing the gravitational action in a scalar-tensor
representation, the new solutions are obtained by either making an ansatz on
the scale factor or on the effective potential. Among other relevant results,
we show that it is possible to obtain exponentially expanding solutions for
flat universes even when the cosmology is not purely vacuum. We then derive the
classes of actions for the original theory which generate these solutions.Comment: 14 pages, 17 figure
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