Panel discussion: inflation targeting

Monetary policy ; Banks and banking, Central ; European Central Bank

Hysteretic resistance spikes in quantum Hall ferromagnets without domains

We use spin-density-functional theory to study recently reported hysteretic magnetoresistance \rho_{xx} spikes in Mn-based 2D electron gases [Jaroszy\'{n}ski et al. Phys. Rev. Lett. (2002)]. We find hysteresis loops in our calculated Landau fan diagrams and total energies signaling quantum-Hall-ferromagnet phase transitions. Spin-dependent exchange-correlation effects are crucial to stabilize the relevant magnetic phases arising from distinct symmetry-broken excited- and ground-state solutions of the Kohn-Sham equations. Besides hysteretic spikes in \rho_{xx}, we predict hysteretic dips in the Hall resistance \rho_{xy}. Our theory, without domain walls, satisfactorily explains the recent data.Comment: 4 pages, 4 figures, published version (some changes to the text; same figures as in v1

Numerical Analysis of Three-dimensional Acoustic Cloaks and Carpets

We start by a review of the chronology of mathematical results on the Dirichlet-to-Neumann map which paved the way towards the physics of transformational acoustics. We then rederive the expression for the (anisotropic) density and bulk modulus appearing in the pressure wave equation written in the transformed coordinates. A spherical acoustic cloak consisting of an alternation of homogeneous isotropic concentric layers is further proposed based on the effective medium theory. This cloak is characterised by a low reflection and good efficiency over a large bandwidth for both near and far fields, which approximates the ideal cloak with a inhomogeneous and anisotropic distribution of material parameters. The latter suffers from singular material parameters on its inner surface. This singularity depends upon the sharpness of corners, if the cloak has an irregular boundary, e.g. a polyhedron cloak becomes more and more singular when the number of vertices increases if it is star shaped. We thus analyse the acoustic response of a non-singular spherical cloak designed by blowing up a small ball instead of a point, as proposed in [Kohn, Shen, Vogelius, Weinstein, Inverse Problems 24, 015016, 2008]. The multilayered approximation of this cloak requires less extreme densities (especially for the lowest bound). Finally, we investigate another type of non-singular cloaks, known as invisibility carpets [Li and Pendry, Phys. Rev. Lett. 101, 203901, 2008], which mimic the reflection by a flat ground.Comment: Latex, 21 pages, 7 Figures, last version submitted to Wave Motion. OCIS Codes: (000.3860) Mathematical methods in physics; (260.2110) Electromagnetic theory; (160.3918) Metamaterials; (160.1190) Anisotropic optical materials; (350.7420) Waves; (230.1040) Acousto-optical devices; (160.1050) Acousto-optical materials; (290.5839) Scattering,invisibility; (230.3205) Invisibility cloak

An experimental and analytical investigation of proprotor whirl flutter

The results of an experimental parametric investigation of whirl flutter are presented for a model consisting of a windmilling propeller-rotor, or proprotor, having blades with offset flapping hinges mounted on a rigid pylon with flexibility in pitch and yaw. The investigation was motivated by the need to establish a large data base from which to assess the predictability of whirl flutter for a proprotor since some question has been raised as to whether flutter in the forward whirl mode could be predicted with confidence. To provide the necessary data base, the parametric study included variation in the pylon pitch and yaw stiffnesses, flapping hinge offset, and blade kinematic pitch-flap coupling over a large range of advance ratios. Cases of forward whirl flutter and of backward whirl flutter are documented. Measured whirl flutter characteristics were shown to be in good agreement with predictions from two different linear stability analyses which employed simple, two dimensional, quasi-steady aerodynamics for the blade loading. On the basis of these results, it appears that proprotor whirl flutter, both forward and backward, can be predicted

Bank Corporate Lending: A Bubble in Progress and Suggested Remedies

The causes of the Great Recession that began in 2008, and the solutions to prevent a recurrence, have been argued over endlessly. The government has responded with various actions: e.g., the Dodd-Frank Act (2010); stronger oversight of the activities of commercial and investment banks; and other measures. A significant unaddressed financial concern are the procedures for bank lending to businesses, which is largely unrestricted as to loan policies, required collateral and other safeguards, and the strength of loan covenants that protect the bank during the duration of the loan. This paper discusses the situation with regard to loan covenants and suggests various remedies

Residential Mortgages and Public Policy: What to do with Fannie and Freddie?

The current debate on U.S. housing policy focuses on the role of the government in supporting the mort-gage market. Existing organizations (Fannie Mae/Freddie Mac) are in conservatorship, and Congress is considering alternative structures and guarantees including catastrophic insurance in support of the coverage from private companies. This research reviews public policy and the experience of governmental catastrophic insurance with particular reference to FDIC coverage for bank accounts

Net Income vs. Cash Flow Analysis: Improving Misleading Financial Reporting

Standard GAAP accrual accounting protocols can contain misleading (and even fraudulent) information because of certain long-acknowledged interpretations required in constructing financial statements. The occurrence of defaults and bankruptcies in recent years has become a serious problem for regulators, investors, lenders and creditors. This poster reviews an alternative document - the statement of cash flows - that inherently is less prone to manipulation and misinterpretation. The research suggested is to compare various failed company profit and loss results just prior to the incident, to the cash flow statement results for the same period

The Decay Properties of the Finite Temperature Density Matrix in Metals

Using ordinary Fourier analysis, the asymptotic decay behavior of the density matrix F(r,r') is derived for the case of a metal at a finite electronic temperature. An oscillatory behavior which is damped exponentially with increasing distance between r and r' is found. The decay rate is not only determined by the electronic temperature, but also by the Fermi energy. The theoretical predictions are confirmed by numerical simulations