Experimental determination of sound and high-speed flow interaction

A facility that was used to measure the interaction of flow with sound at high Mach numbers is described. Four inlets with different area variations (or axial gradients) were tested. Sound of selected frequencies and modes (0,0), (1,0), (2,0) was generated with eight circumferential acoustic drivers

The Dynamics of Emerging Market Equity Flows

We study the interrelationship between capital flows, returns, dividend yields and world interest rates in 20 emerging markets. We estimate a vector autoregressionn with these variables to measure the degree to which lower interest rates contribute to increased capital flows and shocks in flows affect the cost of capital among other dynamic relations. We precede the VAR analysis by a detailed examination of endogenous break points in capital flows and the other variables. These structural breaks are traced to the liberalization of emerging equity markets. Our evidence of structural breaks call into question past research which estimates VAR models over the full sample. After a liberalization, we find that equity flows increase by 1.4% of market capitalization. We also show that shocks in equity flows initially increase returns which is consistent with a price pressure hypothesis. While the effect is diminished over time, there also appears to be a permenant impact. This is consistent with our finding that our proxy for the cost of capital, dividend yields, decreases. Finally, our analysis of the transitition dynamics from pre-liberalization to post-liberalization suggests that when capital leaves, it leaves faster than it came in. These results may help us understand the dynamics of the recent crises in Latin America and East Asia.

Aerodynamic and acoustic performance of high Mach number inlets

Experimental results were obtained for two types of high Mach number inlets, one with a translating centerbody and one with a fixed geometry (collapsing cowl) without centerbody. The aerodynamic and acoustic performance of these inlets was examined. The effects of several parameters such as area ratio and length-diameter ratio were investigated. The translating centerbody inlet was found to be superior to the collapsing cowl inlet both acoustically and aerodynamically, particularly for area ratios greater than 1.5. Comparison of length-diameter ratio and area ratio effects on performance near choked flow showed the latter parameter to be more significant. Also, greater high frequency noise attenuation was achieved by increasing Mach number from low to high subsonic values

Dating the Integration of World Equity Markets

Measuring the integration of world capital markets is notoriously difficult. For example, regulatory changes which appear comprehensive may have little impact on the functioning of the capital market if they fail to lead to foreign portfolio inflows. In contrast to the usual practice of documenting the timing of regulatory changes, we specify a reduced-form model for a number of financial time-series (for example, equity returns and dividend yields) and search for a common break in the process generating the data. In addition, we estimate a confidence interval for the break. Information on a variety of financial and macroeconomic indicators is employed to interpret the results and to identify the likely date the equity market becomes financially integrated with world capital markets. We find endogenous break dates that are very accurately estimated but do not always correspond closely to dates of official capital market reforms. After the break, stock markets are on average larger and more liquid than before; returns are more volatile and more highly correlated with the world market return, dividend yields are lower and credit ratings improve.

Linearly scaling direct method for accurately inverting sparse banded matrices

In many problems in Computational Physics and Chemistry, one finds a special kind of sparse matrices, termed "banded matrices". These matrices, which are defined as having non-zero entries only within a given distance from the main diagonal, need often to be inverted in order to solve the associated linear system of equations. In this work, we introduce a new O(n) algorithm for solving such a system, being n X n the size of the matrix. We produce the analytical recursive expressions that allow to directly obtain the solution, as well as the pseudocode for its computer implementation. Moreover, we review the different options for possibly parallelizing the method, we describe the extension to deal with matrices that are banded plus a small number of non-zero entries outside the band, and we use the same ideas to produce a method for obtaining the full inverse matrix. Finally, we show that the New Algorithm is competitive, both in accuracy and in numerical efficiency, when compared to a standard method based in Gaussian elimination. We do this using sets of large random banded matrices, as well as the ones that appear when one tries to solve the 1D Poisson equation by finite differences.Comment: 24 pages, 5 figures, submitted to J. Comp. Phy

Europeanisation should meet international constructivism: the Nordic Plus group and the internalisation of political conditionality by France and the United Kingdom

This article is a plausibility probe for the significance of international constructivist ‘mediating factors’ to explain variation in Europeanisation outcomes. It applies a most similar systems design (or Mill's method of difference) to show that the UK has internalised political conditionality to a larger extent than France at least partially because it has been the object of stronger socialisation pressures within the ‘Nordic Plus’ group. The article contributes to the literature on Europeanisation and development cooperation in two important ways. First, it enlarges its scope of analysis, both geographically (beyond new European Union member states) and thematically (beyond simple measures of aid quality and/or quantity). Second, it emphasises the importance of international (versus domestic) mediating factors. The empirical analysis focusses on three cases of aid sanctions in response to human rights abuses and democratic setbacks: Zimbabwe 2002, Madagascar 2009 and Mozambique 2009