The Bretton Woods agencies and sub-Saharan Africa in the 1990s : facing the tough questions

Both the International Monetary Fund (IMF) and the World Bank recognize that sub - Saharan Africa (SSA) represents a difficult and complex development challenge. The author proposes that the Bank and the IMF take four institutional steps to deal effectively with the region's problems in the near term. First, the agencies should reconsider their planned net capital contribution to help overcome the region's severe foreign exchange constraints. Secondly, the Brady proposals represented a major conceptual step forward toward alleviating the private debt overhang that seriously burdens at least a dozen countries in the region. Additional efforts to reduce the private debts of the low-income countries will be needed to achieve the objectives of the proposals. Thirdly, the Bank's analysis of the problems facing the region argues for a faster and more comprehensive reform program. In the 1990s the Bretton Woods agencies will face increasing pressures to give more weight to issues of social equity and political variables. Lastly, the Bank and Fund will have to improve their ability to work together to maximize their effectiveness. The Bank and Fund should collaborate in long-term planning for SSA. Policy Framework Papers should go beyond the current three year horizon and plan some issues for five to ten years. The Bank should also take the lead in organizing external assistance efforts and policy reform programs.Environmental Economics&Policies,Banks&Banking Reform,Economic Adjustment and Lending,Strategic Debt Management,Economic Theory&Research

Conformal anomaly as a source of soft photons in heavy ion collisions

We introduce a novel photon production mechanism stemming from the conformal anomaly of QCDxQED and the existence of strong (electro)magnetic fields in heavy ion collisions. Using the hydrodynamical description of the bulk modes of QCD plasma, we show that this mechanism leads to the photon production yield that is comparable to the yield from conventional sources. This mechanism also provides a significant positive contribution to the azimuthal anisotropy of photons, $v_2$, as well as to the radial "flow". We compare our results to the data from the PHENIX Collaboration.Comment: 5 pages, 3 figures; version accepted to Phys. Rev. Let

Deconfinement of Constituent Quarks and the Hagedorn Temperature

The double phase transition of hadronic matter, $H$, first, to the gas of deconfined constituent quarks (for brevity called {\it valons}), $Q$, and then, secondly, the phase transition from $Q$ to quark-gluon plasma, $QGP$, is considered within bag model ideology. In distinction from previous double phase transition investigations, it is not supposed that at zero chemical potential (~$\mu=0$~) transition temperatures $T_d$ (for $H~\leftrightarrow~Q$) and $T_{ch}$ (for $Q~\leftrightarrow~ QGP$, chiral restoration) coincide. Then for plausible range of chosen bag constants, $B_Q$ for $Q$ and $B_q$ for $QGP$ the phase transition $H~ \leftrightarrow~ QGP$ can proceed {\it only via the $Q$ phase} (at least at not too much $\mu$). For small $\mu$ the gap, $T_{ch}~-~T_d$, is quite essential, up to $\approx~50$ MeV. The physical meaning of the $H~ \leftrightarrow~ Q$ transition temperature, $T_d$, coincide with that of the Hagedorn temperature, $T_H$.Comment: 9 pages, 11 Postscript figure

Effects of Bose-Einstein Condensation on forces among bodies sitting in a boson heat bath

We explore the consequences of Bose-Einstein condensation on two-scalar-exchange mediated forces among bodies that sit in a boson gas. We find that below the condensation temperature the range of the forces becomes infinite while it is finite at temperatures above condensation.Comment: 10 pages, 2 figure

Optimality Inequalities for Average Cost Markov Decision Processes and the Optimality of (s,S) Policies

Optimality Inequalities for Average Cost Markov Decision Processes and the Optimality of (s,S) Policie