920 resultados para Real and nominal effective exchange rates
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Some properties of the higher grading integrable generalizations of the conformal affine Toda systems are studied. The fields associated to the non-zero grade generators are Dirac spinors. The effective action is written in terms of the Wess-Zumino-Novikov-Witten (WZNW) action associated to an affine Lie algebra, and an off-critical theory is obtained as the result of the spontaneous breakdown of the conformal symmetry. Moreover, the off-critical theory presents a remarkable equivalence between the Noether and topological currents of the model. Related to the off-critical model we define a real and local lagrangian provided some reality conditions are imposed on the fields of the model. This real action model is expected to describe the soliton sector of the original model, and turns out to be the master action from which we uncover the weak-strong phases described by (generalized) massive Thirring and sine-Gordon type models, respectively. The case of any (untwisted) affine Lie algebra furnished with the principal gradation is studied in some detail. The example of s^l(n) (n = 2, 3) is presented explicitly. © SISSA/ISAS 2003.
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Incluye Bibliografía
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Incluye Bibliografía
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Chiral symmetry breaking in QCD is studied introducing a confining effective propagator, as proposed recently by Cornwall, and considering the effect of dynamically massive gluons. The effective confining propagator has the form 1/(k2 +m2)2 and we study the bifurcation equation finding limits on the parameter m below which a satisfactory fermion mass solution is generated. Since the coupling constant and gluon propagator are damped in the infrared, due to the presence of a dynamical gluon mass, the major part of the chiral breaking is only due to the confining propagator and related to the low momentum region of the gap equation. We study the asymptotic behavior of the gap equation containing this confinement effect and massive gluon exchange, and find that the symmetry breaking can be approximated by an effective four-fermion interaction generated by the confining propagator. We compute some QCD chiral parameters as a function of m, finding values compatible with the experimental data. We find a simple approximate relation between the fermion condensate and dynamical mass for a given representation as a function of the parameters appearing in the effective confining propagator. © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence.
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Introduction The social agenda is long-term in nature, in the sense that poverty alleviation along with a better distribution of income, wealth and opportunities are long-term goals. A sound macroeconomic policy, on the other hand, has to do largely with the consistent management of short-term policy instruments pursuing a sustainable and predictable pace for aggregate economic variables and major prices (wages, inflation, interest rates and exchange rates). In spite of the different arena and rationale in which they play, there are strong links between the two. First and most obvious, macroeconomic adjustment and structural reform are more likely to be sustainable when they are equitable. Second, social intervention —i.e., policies, programmes and reforms aimed at improving social performance in the long run—, needs stable funding which is not always available in view of macroeconomic constraints. Third, macroeconomic instability —especially episodes of recession or hyperinflation— increases poverty and inequality, while restoring macroeconomic equilibrium does not restore previous social balances. Finally, there is no unique macroeconomic policy mix to tackle a given situation, and the policy options may not be neutral from a social standpoint. Monetary, fiscal and exchange rate policies, together with structural reform, have major consequences for the social wellbeing of societies, not only in terms of protection against shocks and crises but also in terms of equity. Many, if not all, of the necessary social policies are of a domestic nature. This report thus concentrates on domestic strategies aimed at maximizing the linkages between consistent macroeconomic policies and social progress. Pursuing them, however, depends to a considerable extent on the international enabling environment in which the global financial system, the unsettled debt crisis and increasing ODA flows play a significant role. Countries operate in a world economy where market players everywhere immediately scrutinize domestic monetary, financial or fiscal policy decisions and the performance of exchange rate regimes of individual countries. Under these conditions, the room for manoeuvre of policymakers has become considerably constrained. Consequently, it is becoming increasingly complex to incorporate the social dimensions into such policy decisions, to the extent that external analysts consider that authorities are sacrificing sound macroeconomic policies. The main message of the report is that the expediency of short-term economic efficiency as embedded in much of the advice on macroeconomic stability needs to be tempered by long-term development objectives. The report starts with a short historical background which describes the ascendancy of macroeconomic policies over social development policies (chapter I). It continues with an evaluation of the relation between macroeconomic consistency and social effort (chapter II), and the importance of sustainable and stable growth for social progress (chapter III). The report then turns to the need for an equity-enhancing growth strategy (chapter IV) and an analysis of the priorities of social policies in an integrated approach to growth (chapter V). The final chapter adds some final institutional remarks.
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