The Origin of Warped, Precessing Disks in X-Ray Binaries

The radiation-driven warping instability discovered by Pringle holds considerable promise as the mechanism responsible for producing warped, precessing accretion disks in X-ray binaries. This instability is an inherently global mode of the disk, thereby avoiding the difficulties with earlier models for the precession. Here we follow up earlier work to study the linear behavior of the instability in the specific context of a binary system. We treat the influence of the companion as an orbit-averaged, quadrupole torque on the disk. The presence of this external torque allows the existence of solutions in which the direction of precession of the warp is retrograde with respect to disk rotation, in addition to the prograde solutions which exist in the absence of external torques.Comment: 12 pages, 3 figure

Strong Evidence for a Buried AGN in UGC 5101: Implications for LINER-Type Ultra-Luminous Infrared Galaxies

We report on the results of 3--4 $\mu$m spectroscopy of the ultra-luminous infrared galaxy (ULIRG) UGC 5101. It has a cool far-infrared color and a LINER-type optical spectrum, and so, based on a view gaining some currency, would be regarded as dominated by star formation. However, we find that it has strong 3.4 $\mu$m carbonaceous dust absorption, low-equivalent-width 3.3 $\mu$m polycyclic aromatic hydrocarbon (PAH) emission, and a small 3.3 $\mu$m PAH to far-infrared luminosity ratio. This favors an alternative scenario, in which an energetically dominant AGN is present behind obscuring dust. The AGN is plausibly obscured along all lines of sight (a `buried AGN'), rather than merely obscured along our particular line of sight. Such buried AGNs have previously been found in thermal infrared studies of the ULIRGs IRAS 08572+3915 and IRAS F00183$-$7111, both classified optically as LINERs. We argue that buried AGNs can produce LINER-type optical spectra, and that at least some fraction of LINER-type ULIRGs are predominantly powered by buried AGNs.Comment: 11 pages, 1 figure, accepted by ApJ Lette

Erratum: Luminosity function, sizes and FR dichotomy of radio-loud AGN

This erratum corrects a number of formulae containing mistakes in the paper 'Luminosity function, sizes and FR dichotomy of radio-loud AGN', 2007, MNRAS, v. 381, p.1548. The corrections do not alter any of the conclusions in the original paper.Comment: single page, no figures, erratum to MNRAS, 2007, v. 381, p. 154

Financial exchange rates and international currency exposures

Our goal in this project is to gain a better empirical understanding of the international financial implications of currency movements. To this end, we construct a database of international currency exposures for a large panel of countries over 1990-2004. We show that trade-weighted exchange rate indices are insufficient to understand the financial impact of currency movements. We show that our currency measure has high explanatory power for the valuation term in net foreign asset dynamics: exchange rate valuation shocks are sizable, not quickly reversed and may entail substantial wealth redistributions. Further, we demonstrate that many developing countries hold short foreign-currency positions, leaving them open to negative valuation effects when the domestic currency depreciates. However, we also show that many of these countries have substantially reduced their foreign currency exposure over the last decade. --Financial integration,capital flows,external assets and liabilities

Financial Exchange Rates and International Currency Exposures

Our goal in this project is to gain a better empirical understanding of the international financial implications of currency movements. To this end, we construct a database of international currency exposures for a large panel of countries over 1990-2004. We show that trade-weighted exchange rate indices are insufficient to understand the financial impact of currency movements. Further, we demonstrate that many developing countries hold short foreign-currency positions, leaving them open to negative valuation effects when the domestic currency depreciates. However, we also show that many of these countries have substantially reduced their foreign currency exposure over the last decade. Last, we show that our currency measure has high explanatory power for the valuation term in net foreign asset dynamics: exchange rate valuation shocks are sizable, not quickly reversed and may entail substantial wealth shocks.Financial integration, capital flows, external assets and liabilities

AGRICULTURAL POLICY DEVELOPMENTS IN THE UNITED STATES: 1991-93

Agricultural and Food Policy,

TRENDS AND DEVELOPMENTS IN UNITED STATES AGRICULTURAL POLICY: 1993-1995

A number of factors including budget pressures, emphasis on environmentally sensitive agriculture, emphasis on finding agricultural export markets, and anti-agricultural program sentiment have fueled a climate for change in United States agricultural policy. Whether significant changes will occur depends on the political strength of agricultural interest groups and on the compromises which can be reached between them. Several notable achievements have been accomplished in recent domestic agricultural policy legislation. The 1995 farm bill will define the commodity and conservation programs for the next five years. In addition to domestic developments, there have been history-setting accomplishments in reducing barriers to international agricultural trade. The tri-partite North American Free Trade Agreement became effective January 1, 1994. The Uruguay Round Agreement of the General Agreement on Tariffs and Trade was completed in late 1994 and will become effective in 1995.Agricultural and Food Policy,