Structural Change in Transition Economies: Does Foreign Aid Matter?

This paper addresses whether the initial declines in the manufacturing and real wages in transition economies were anything unexpected to justify policy reversal, and whether the “often-recommended” foreign aid would have helped them curb these declines in any significant way. It answers these questions with the help of a two-sector three-factor small open economy model and simulation exercises. It concludes that, given the relative price distortions and the market disequilibria that transition economies inherited from their planning era, the initial declines in their manufacturing and real wages are to be mostly expected. Foreign aid, whose impact is noticeable only when it is in excess of 5% of GDP, does not curb the decline in their real wages in any measurable way and exacerbates the decline in their manufacturing by a few percent.liberalization, structural adjustment, transition economies, East European economies, Soviet Republics, foreign aid

Terahertz Radiation Power Characterization and Optimization of Stack of Intrinsic Josephson Junctions

Terahertz radiation of the stack of intrinsic Josephson junctions in the mesa structure of the layered high-Tc superconductors is analyzed and presented in this work. The dependency of the radiated power to the geometrical parameters, cavity-waveguide boundaries, and magnetic and electric bias has been investigated. This has been done by numerical calculation of the previously proposed coupled sine-Gordon equations, which characterize the electromagnetic dynamics of the stack of the intrinsic Josephson junctions. Using the obtained numerical results from these coupled equations, the effect of the design parameters such as dimensions of the mesa structure and the magnitude of the applied magnetic field and the dc current on the enhancement of the radiated power is studied. Thus, the radiated power is optimized with respect to these considered parameters. By variation of the number of layers, we also investigate the effect of the number of intrinsic Josephson junctions on the total radiated power. The results from this part are also compared with the previous analytical models.Comment: 8 pages, 8 figure

Analytic thermal modeling for dc to midrange modulation frequency response for thin film high-Tc superconductive edge-transition bolometers

Cataloged from PDF version of article.Thin-film superconductive edge-transition bolometers are modeled with a one-dimensional analytic thermal model with joule heating, film and substrate materials, and the physical interface effects taken into consideration. The results from the model agree well with the experimental results of samples made of large-meander-line Yba(2)Cu(3)O(7-x) films on crystalline SrTiO3, LaAlO3, and MgO substrates up to 100 kHz, the limits of the experimental setup. Compared with the results of the SrTiO3 substrate samples, the results from the model of the LaAlO3 and the MgO substrate samples deviate slightly from the measured values at very low modulation frequencies (below similar to 10 Hz). The deviation increases for higher thermal-conductive substrate materials. When the model was used, the substrate absorption and the thermal parameters of the devices could also be investigated. (C) 2001 Optical Society of Americ

Foreign Exchange Controls, Fiscal and Monetary Policy, and the Black Market Premium

This paper examines the relationship between the official and parallel exchange rates, in three Caribbean countries, Guyana, Jamaica and Trinidad, during the 1985-1993 period using cointegration, Granger causality, and reduced form methods. The official and parallel rates are cointegrated in all three countries, but with significant average disparity between them in Guyana and Trinidad, which unlike Jamaica applied infrequent and large adjustments to their official rates. The causation is bi-directional in the case of Jamaica and uni-directional, with changes in the official rate Granger causing changes in the parallel rate, in the cases of Guyana and Trinidad, reflecting the difference in their official exchange rate policies. Our reduced form estimates indicate that exchange controls, expansionary fiscal and monetary policy, and changes of government mostly have the expected positive effect on the black market premium. After past values of the premium, exchange controls exert the strongest impact on the premium.Foreign Exchange Controls, Black Market Exchange Rate, Black Market Premium, Cointegration, Granger Causality

HTS YBCO Resonator Configuration with Coplanar Optimized Flux Concentrator Strongly Coupled to rf SQUID

We developed a novel magnetic coupling module formed of a monolayer superconducting flux concentrator, which is integrated with a coplanar resonator strongly coupled to HTS rf-SQUID. Three types of resonators, including a long stripline resonator between input loop and pick-up loop of the flux concentrator, a complementary split ring resonator (CSRR), and also a spiral shape inside the input loop are explored. The resonance quality factors as well as the coupling to the SQUID of different patterns of these three types of the resonators is evaluated using Finite Element Method (FEM) simulations. Several readout methods to couple the electronic system to the resonators are tested, including inductive (coil) and capacitive (transmission line) couplings, and the optimum readout is reported for each of the resonators. Among the evaluated resonator types, a spiral shape resonator with optimal design showing the highest quality factor (5900) together with the strongest coupling to the SQUID (-0.5 dB) at resonance frequency of 836 MHz, is fabricated using 200 nm thick superconducting YBCO on a 1 mm thick crystalline LaAlO3 substrate. The flux concentrator of the module is optimized by the variation of its linewidths and also its input loop radius to obtain maximum flux transformation efficiency.Comment: 5 page