Scalar conservation laws with stochastic forcing

We show that the Cauchy Problem for a randomly forced, periodic multi-dimensional scalar first-order conservation law with additive or multiplicative noise is well-posed: it admits a unique solution, characterized by a kinetic formulation of the problem, which is the limit of the solution of the stochastic parabolic approximation

The determinants of "domestic" original sin in emerging market economies

This paper explains why domestic debt composition in some emerging economies is risky. To this end, it carries out a systematic analysis of the determinants of the so-called domestic original sin, which refers to the inability of emerging economies to borrow domestically in local currency, at long maturities and fixed interest rates. As such, the latter is a measure of financial vulnerabilities arising from domestic debt composition, which encompasses maturity mismatches, rollover risk and interest payment contingency. The paper builds on a large dataset compiled by the authors from national sources. It finds that domestic original sin is particularly severe when inflation is lofty, the debt service-to-GDP ration high, the slope of the yield curve inverted and the investor base narrow. These results suggest that sound macroeconomic policies, attractive long-term yields and policies aimed at widening the investor base are instrumental to overcome domestic original sin, reduce domestic debt riskiness and tilt its composition towards safer, long-term, unindexed, local currency instrumentsOriginal sin, domestic debt, emerging economies

Domestic Debt Structures in Emerging Markets : New Empirical Evidence

This paper explains why public domestic debt composition in emerging economies can be risky, namely in foreign currency, with a short maturity or indexed. It analyses empirically the determinants of these risk sources separately, developing a new large dataset compiled from national sources for 33 emerging economies over 1994-2006. The paper finds that economic size, the breadth of the domestic investor base, inflation and fiscal soundness are all associated with risky public domestic debt compositions, yet to an extent that varies considerably in terms of magnitude and significance across sources of risk. Only inflation impacts all types of risky debt, underscoring the overarching importance of monetary credibility to make domestic debt compositions in emerging economies safer. Given local bond markets' rapid development, monitoring risky public domestic debt compositions in emerging economies becomes increasingly relevant to global financial stability.Public domestic debt, composition, risk, emerging economies.

The determinants of ‘domestic’ original sin in emerging market economies

This paper explains why domestic debt composition in emerging economies is risky. It carries out an analysis of the determinants of ‘domestic’ original sin, which refers to the inability of emerging economies to borrow domestically in local currency, at long maturities and fixed interest rates. The latter is a measure of financial vulnerabilities arising from domestic debt composition, which encompasses maturity mismatches, rollover risk and interest payment contingency. The paper builds on a large dataset compiled by the authors from national sources. It finds that domestic original sin is severe when inflation is lofty, the debt service-to-GDP ratio high, the slope of the yield curve inverted and the investor base narrow. These results suggest that sound macroeconomic policies, attractive long-term yields and policies aimed at widening the investor base are instrumental to reduce domestic debt riskiness and tilt its composition towards safer, long-term, unindexed, local currency instruments. JEL Classification: F34, F41, G15domestic debt, emerging economies, Original sin

Incompatibility boundaries for properties of community partitions

We prove the incompatibility of certain desirable properties of community partition quality functions. Our results generalize the impossibility result of [Kleinberg 2003] by considering sets of weaker properties. In particular, we use an alternative notion to solve the central issue of the consistency property. (The latter means that modifying the graph in a way consistent with a partition should not have counterintuitive effects). Our results clearly show that community partition methods should not be expected to perfectly satisfy all ideally desired properties. We then proceed to show that this incompatibility no longer holds when slightly relaxed versions of the properties are considered, and we provide in fact examples of simple quality functions satisfying these relaxed properties. An experimental study of these quality functions shows a behavior comparable to established methods in some situations, but more debatable results in others. This suggests that defining a notion of good partition in communities probably requires imposing additional properties.Comment: 17 pages, 3 figure

Load management strategy for Particle-In-Cell simulations in high energy particle acceleration

In the wake of the intense effort made for the experimental CILEX project, numerical simulation cam- paigns have been carried out in order to finalize the design of the facility and to identify optimal laser and plasma parameters. These simulations bring, of course, important insight into the fundamental physics at play. As a by-product, they also characterize the quality of our theoretical and numerical models. In this paper, we compare the results given by different codes and point out algorithmic lim- itations both in terms of physical accuracy and computational performances. These limitations are illu- strated in the context of electron laser wakefield acceleration (LWFA). The main limitation we identify in state-of-the-art Particle-In-Cell (PIC) codes is computational load imbalance. We propose an innovative algorithm to deal with this specific issue as well as milestones towards a modern, accurate high-per- formance PIC code for high energy particle acceleration

A pressure impulse theory for hemispherical liquid impact problems

Liquid impact problems for hemispherical fluid domain are considered. By using the concept of pressure impulse we show that the solution of the flow induced by the impact is reduced to the derivation of Laplace's equation in spherical coordinates with Dirichlet and Neumann boundary conditions. The structure of the flow at the impact moment is deduced from the spherical harmonics representation of the solution. In particular we show that the slip velocity has a logarithmic singularity at the contact line. The theoretical predictions are in very good agreement both qualitatively and quantitatively with the first time step of a numerical simulation with a Navier-Stokes solver named Gerris.Comment: 11 pages, 14 figures, Accepted for publication in European Journal of Mechanics - B/Fluid

Diffusion limit for the radiative transfer equation perturbed by a Wiener process

The aim of this paper is the rigorous derivation of a stochastic non-linear diffusion equation from a radiative transfer equation perturbed with a random noise. The proof of the convergence relies on a formal Hilbert expansion and the estimation of the remainder. The Hilbert expansion has to be done up to order 3 to overcome some diffculties caused by the random noise.Comment: 27 page