Dual exposure interferometry

The application of dual exposure differential interferometry to gas dynamics and flow visualization is discussed. A differential interferometer with Wallaston prisms can produce two complementary interference fringe systems, depending on the polarization of the incident light. If these two systems are superimposed on a film, with one exposure during a phenomenon, the other before or after, the phenomenon will appear on a uniform background. By regulating the interferometer to infinite fringe distance, a resolution limit of approximately lambda/500 can be obtained in the quantitative analysis of weak phase objects. This method was successfully applied to gas dynamic investigations

Nonlinear magnetoacoustic waves in a cold plasma

The equations describing planar magnetoacoustic waves of permanent form in a cold plasma are rewritten so as to highlight the presence of a naturally small parameter equal to the ratio of the electron and ion masses. If the magnetic field is not nearly perpendicular to the direction of wave propagation, this allows us to use a multiple-scale expansion to demonstrate the existence and nature of nonlinear wave solutions. Such solutions are found to have a rapid oscillation of constant amplitude superimposed on the underlying large-scale variation. The approximate equations for the large-scale variation are obtained by making an adiabatic approximation and in one limit, new explicit solitary pulse solutions are found. In the case of a perpendicular magnetic field, conditions for the existence of solitary pulses are derived. Our results are consistent with earlier studies which were restricted to waves having a velocity close to that of long-wavelength linear magnetoacoustic waves

A solitary-wave solution to a perturbed KdV equation

We derive the approximate form and speed of a solitary-wave solution to a perturbed KdV equation. Using a conventional perturbation expansion, one can derive a first-order correction to the solitary-wave speed, but at the next order, algebraically secular terms appear, which produce divergences that render the solution unphysical. These terms must be treated by a regrouping procedure developed by us previously. In this way, higher-order corrections to the speed are obtained, along with a form of solution that is bounded in space. For this particular perturbed KdV equation, it is found that there is only one possible solitary wave that has a form similar to the unperturbed soliton solution

Post-resolution treatment of depositors at failed banks: implications for the severity of banking crises, systemic risk, and too-big-to-fail

Bank failures are widely viewed in all countries as more damaging to the economy than the failure of other firms of similar size for a number of reasons. The failures may produce losses to depositors and other creditors, break long-standing bank-customers loan relationships, disrupt the payments system, and spillover in domino fashion to other banks, financial institutions and markets, and even to the macroeconomy (Kaufman, 1996). Thus, bank failures are viewed as potentially more likely to involve contagion or systemic risk than the collapse of other firms. The risk of such actual or perceived damage is often a popular justification for explicit or implicit government-provided or sponsored safety nets under banks, including explicit deposit insurance and implicit government guarantees, such as "too-big-to-fail" (TBTF), that may protect de jure uninsured depositors and possibly other bank stakeholders against some or all of the loss.Bank failures ; Deposit insurance

Post-resolution treatment of depositors at failed banks: implications for the severity of banking crises, systemic risk, and too big to fail

Losses from bank failures have significant adverse implications for bank stakeholders, as well as for the macroeconomy. This article examines the potential sources of such losses, in particular the losses that may occur after the date a bank is failed, and makes recommendations on how to minimize these losses.Bank failures ; Financial crises ; Deposit insurance ; Bank deposits

The Vicious Cycle of the Foreign Military Debt

This paper aims at estimating first the effects of defense spending on the main determinants of growth, and second the extent to and the channels through which the military debt of Greece influences the overall debt burden of the country, and consequently the critical determinants of economic growth and development. Increased imports of sophisticated weapons and military equipment can be financed at the cost of investment (guns v. ploughshares), or/and at the cost of human capital formation (guns v. butter and chalk), or at the cost of increasing the foreign debt of the country. It is this last case which is investigated in this paper. Our empirical results indicate that whatever the necessity and the benefits of the security aspect of defense, its economic costs are quite substantial. The military as a claimant of resources has a negative and non trivial effect on physical capital accumulation, and human capital formation. Moreover, financing increased military imports through borrowing from abroad has a negative and significant effect on the determinants of growth and development.Key Words: Defense Burden, Foreign Military Debt, Growth Rate, Investment, Education.

Bank crisis resolution and foreign-owned banks

In many countries in recent years, failure to efficiently resolve large insolvent banks has come at a high cost both to taxpayers and to the countries’ aggregate income. The increasing entry of foreign banks has complicated the resolution process. ; This article explores some special problems in the efficient resolution of insolvent banks raised by cross border banking, particularly weighing the costs and benefits of foreign bank entry via branches versus subsidiary banks. These problems lie primarily in the cross country differences in both the closure rule and the deposit insurance structure. ; The authors propose a four-point program for resolving insolvent institutions efficiently but note that the presence of foreign-owned banks may make adhering to these principles difficult. To mitigate these problems, the authors propose several policies: central multinational deposit insurance, a single insolvency resolution agency, and common or harmonized laws regarding insolvency resolution and enforcement. ; In the absence of such policies, the authors suggest that entry by way of subsidiaries rather than branches presents the lesser set of problems for the host country. For all forms of entry, they conclude, resolution costs can be most effectively controlled through the universal adoption of well-designed and enforced prompt corrective action policies and legal closure rules based on market values of assets and liabilities.Bank failures