The low-temperature superstructure of a 0 -NaV 2 O 5 is determined by synchrotron radiation x-ray diffraction. The high-temperature structure is confirmed to be centrosymmetric, but the modulated structure is found to be acentric Fmm2 on the 2a 3 2b 3 4c supercell. An analysis using superspace symmetry shows that there are modulated and nonmodulated chains of vanadium atoms, tentatively assigned to magnetic and nonmagnetic chains. The arrangement of these chains is different from any model previously considered. [S0031-9007 (99)09001-8] PACS numbers: 61.44.Fw, 61.50.Ks, 61.66.Fn, 75.30.FvAn intensified interest in low-dimensional quantum systems was incited by the discovery of the first inorganic spin-Peierls compound CuGeO 3 [1]. The magnetic order corresponded to a superstructure comprising a dimerization of the copper atoms along the chains, with displacements of neighboring oxygen atoms through elastic coupling [2]. This model was in full accordance with a pairing of the spins on the copper chains. Modulations on neighboring chains were out of phase, thus explaining the second component of one-half of the modulation wave vector.More recently, a 0 -NaV 2 O 5 was found to exhibit a spin-Peierls transition at T SP 34 K [3]. Superstructure reflections in x-ray scattering were observed at q ͑ 1 2 ,

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DISCLAIMER: Staff Discussion Notes (SDNs) showcase policy-related analysis and research being developed by IMF staff members and are published to elicit comments and to encourage debate. The views expressed in Staff Discussion Notes are those of the author(s) and do not necessarily represent the views of the IMF, its Executive Board, or IMF management.

This paper examines the impact of macroeconomic and financial sector policy announcements in the United States, the United Kingdom, the euro area, and Japan during the recent crisis on interbank credit and liquidity risk premia. Announcements of interest rate cuts, liquidity support, liability guarantees, and recapitalization were associated with a reduction of interbank risk premia, albeit to a different degree during the subprime and global phases of the crisis. Decisions not to reduce interest rates and bail out individual banks in an ad hoc manner had adverse repercussions, both domestically and abroad. The results are robust to controlling for the surprise content of announcements and using alternative measures of financial distress.

This Working Paper should not be reported as representing the views of the IMF.The views expressed in this Working Paper are those of the author(s) and do not necessarily represent those of the IMF or IMF policy. Working Papers describe research in progress by the author(s) and are published to elicit comments and to further debate. JEL Classification Numbers:

This Policy Discussion Paper should not be reported as representing the views of the IMF. The views expressed in this Policy Discussion Paper are those of the author(s) and do not necessarily represent those of the IMF or IMF policy. Policy Discussion Papers describe research in progress by the author(s) and are published to elicit comments and to further debate. Recent years have witnessed a surge in the issuance of Islamic capital market securities (sukuk) by corporates and public sector entities amid growing demand for alternative investments. As the sukuk market continues to develop, new challenges and opportunities for sovereign debt managers and capital market development arise. This paper reviews the key developments in the sukuk market and informs the debate about challenges and opportunities going forward.

The global financial crisis has placed the spotlight squarely on bank stress tests. Stress tests conducted in the lead-up to the crisis, including those by IMF staff, were not always able to identify the right risks and vulnerabilities. Since then, IMF staff has developed more robust stress testing methods and models and adopted a more coherent and consistent approach. This paper articulates the solvency stress testing framework that is being applied in the IMF's surveillance of member countries' banking systems, and discusses examples of its actual implementation in FSAPs to 18 countries which are in the group comprising the 25 most systemically important financial systems ("S-25") plus other G-20 countries. In doing so, the paper also offers useful guidance for readers seeking to develop their own stress testing frameworks and country authorities preparing for FSAPs. A detailed Stress Test Matrix (STeM) comparing the stress test parameters applie in each of these major country FSAPs is provided, together with our stress test output templates.

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