How do very open economies adjust to large immigration flows? Recent evidence from Spanish regions

In recent years, Spain has received unprecedented immigration flows. Between 2001 and 2006 the fraction of the population born abroad more than doubled, increasing from4.8% to 10.8%. For Spanish provinces with above-median inflows (relative to population),immigration increased by 24% the number of high school dropouts while only increasingcollege graduates by 11%. We study different channels by which regional labor markets haveabsorbed the large increase in relative supply of low educated workers. We identify theexogenous supply shock using historical immigrant settlement patterns by country of origin.Using data from the Labor Force Survey and the decennial Census, we find a large expansion ofemployment in high immigration regions. Disaggregating by industry, the absorption operatedthrough large increases in the share of low-educated workers, compared to the same industry inlow-immigration regions. We do not find changes in sectoral specialization. Overall, andperhaps surprisingly, the pattern of absorption is very similar to the one found in the US.

Gross capital flows: Dynamics and crises

This paper analyzes the behavior of international capital flows by foreign and domestic agents,dubbed gross capital flows, over the business cycle and during financial crises. We show thatgross capital flows are very large and volatile, especially relative to net capital flows. Whenforeigners invest in a country, domestic agents invest abroad, and vice versa. Gross capital flowsare also pro-cyclical. During expansions, foreigners invest more domestically and domesticagents invest more abroad. During crises, total gross flows collapse and there is a retrenchmentin both inflows by foreigners and outflows by domestic agents. These patterns hold for differenttypes of capital flows and crises. This evidence sheds light on the sources of fluctuations drivingcapital flows and helps discriminate among existing theories. Our findings seem consistent withcrises affecting domestic and foreign agents asymmetrically, as would be the case under thepresence of sovereign risk or asymmetric information.

International capital flows and credit market imperfections: A tale of two frictions

The financial crisis of 2007-08 has underscored the importance of adverse selection in financialmarkets. This friction has been mostly neglected by macroeconomic models of financialimperfections, however, which have focused almost exclusively on the effects of limited pledgeability.In this paper, we fill this gap by developing a standard growth model with adverseselection. Our main results are that, by fostering unproductive investment, adverse selection:(i) leads to an increase in the economy s equilibrium interest rate, and; (ii) it generates a negativewedge between the marginal return to investment and the equilibrium interest rate. Underfinancial integration, we show how this translates into excessive capital inflows and endogenouscycles. We also extend our model to the more general case in which adverse selection and limitedpledgeability coexist. We conclude that both frictions complement one another and show thatlimited pledgeability exacerbates the effects of adverse selection.

Late and post-Hercyniam low temperature veins in the Catalonian Coastal Ranges

Many of the veins enclosed within the Paleozoic basement of the Catalonian Coastal Ranges show severa1 common characteristics: low temperature of formation (between 75 and 200C), the presence of complex polisaline fluids and a certain relationship to the pretriassic paleosurface. Mineralogical composition and age are variable, ranging from Pb-Zn veins with carbonate gangue of late Hercynian age through metal poor fluorite rich veins to barite rich veins of Triasssic age. Mineralizing fluids are not related to late Hercynianmagmatism and deposition took place in active fractures developed either in extensional as in compressive regimes.

The Hercynian ore deposits from the Catalonian Coastal Ranges

Many mineralizations, showings and geochemical anomalies have been found in the Hercynian of the Catalonian Coastal Ranges during the last ten years. Many of them are enclosed in the Paleozoic sediments and volcanics and display pre-metamorphic syngenetic characteristics. The lower carboniferous manganese and base meta1 deposits appear to be formed from hydrothermal fluids springing up in the sea floor through active fractures controlling the filling of the basins in a extensional geotectonic setting. Although less evidence and more controversy is available, similar ore forming processes could have taken place in older Paleozoic times. The deformation and metamorphism have not played an important remobilization role, and most epigenetic deposits of Hercynian age are related to the hydrothermal cells induced by the post-metamorphic granitic intrusives.

Impacts on the deep-sea ecosystem by a severe coastal storm

Major coastal storms, associated with strong winds, high waves and intensified currents, and occasionally with heavy rains and flash floods, are mostly known because of the serious damage they can cause along the shoreline and the threats they pose to navigation. However, there is a profound lack of knowledge on the deep-sea impacts of severe coastal storms. Concurrent measurements of key parameters along the coast and in the deep-sea are extremely rare. Here we present a unique data set showing how one of the most extreme coastal storms of the last decades lashing the Western Mediterranean Sea rapidly impacted the deep-sea ecosystem. The storm peaked the 26th of December 2008 leading to the remobilization of a shallow-water reservoir of marine organic carbon associated with fine particles and resulting in its redistribution across the deep basin. The storm also initiated the movement of large amounts of coarse shelf sediment, which abraded and buried benthic communities. Our findings demonstrate, first, that severe coastal storms are highly efficient in transporting organic carbon from shallow water to deep water, thus contributing to its sequestration and, second, that natural, intermittent atmospheric drivers sensitive to global climate change have the potential to tremendously impact the largest and least known ecosystem on Earth, the deep-sea ecosystem.

Anomalous roughening of Hele-Shaw flows with quenched disorder

The kinetic roughening of a stable oil-air interface moving in a Hele-Shaw cell that contains a quenched columnar disorder (tracks) has been studied. A capillary effect is responsible for the dynamic evolution of the resulting rough interface, which exhibits anomalous scaling. The three independent exponents needed to characterize the anomalous scaling are determined experimentally. The anomalous scaling is explained in terms of the initial acceleration and subsequent deceleration of the interface tips in the tracks coupled by mass conservation. A phenomenological model that reproduces the measured global and local exponents is introduced.

Systematic weakly nonlinear analysis of interfacial instabilities in Hele-Shaw flows

We develop a systematic method to derive all orders of mode couplings in a weakly nonlinear approach to the dynamics of the interface between two immiscible viscous fluids in a Hele-Shaw cell. The method is completely general: it applies to arbitrary geometry and driving. Here we apply it to the channel geometry driven by gravity and pressure. The finite radius of convergence of the mode-coupling expansion is found. Calculation up to third-order couplings is done, which is necessary to account for the time-dependent Saffman-Taylor finger solution and the case of zero viscosity contrast. The explicit results provide relevant analytical information about the role that the viscosity contrast and the surface tension play in the dynamics of the system. We finally check the quantitative validity of different orders of approximation and a resummation scheme against a physically relevant, exact time-dependent solution. The agreement between the low-order approximations and the exact solution is excellent within the radius of convergence, and is even reasonably good beyond this radius.

Phase-field model of Hele-Shaw flows in the high-viscosity contrast regime

A one-sided phase-field model is proposed to study the dynamics of unstable interfaces of Hele-Shaw flows in the high viscosity contrast regime. The corresponding macroscopic equations are obtained by means of an asymptotic expansion from the phase-field model. Numerical integrations of the phase-field model in a rectangular Hele-Shaw cell reproduce finger competition with the final evolution to a steady-state finger.

Particle dispersion in synthetic turbulent flows

We study particle dispersion advected by a synthetic turbulent flow from a Lagrangian perspective and focus on the two-particle and cluster dispersion by the flow. It has been recently reported that Richardson¿s law for the two-particle dispersion can stem from different dispersion mechanisms, and can be dominated by either diffusive or ballistic events. The nature of the Richardson dispersion depends on the parameters of our flow and is discussed in terms of the values of a persistence parameter expressing the relative importance of the two above-mentioned mechanisms. We support this analysis by studying the distribution of interparticle distances, the relative velocity correlation functions, as well as the relative trajectories.

Phase-field model for Hele-Shaw flows with arabitrary contrast II: numerical approach

We present a phase-field model for the dynamics of the interface between two inmiscible fluids with arbitrary viscosity contrast in a rectangular Hele-Shaw cell. With asymptotic matching techniques we check the model to yield the right Hele-Shaw equations in the sharp-interface limit, and compute the corrections to these equations to first order in the interface thickness. We also compute the effect of such corrections on the linear dispersion relation of the planar interface. We discuss in detail the conditions on the interface thickness to control the accuracy and convergence of the phase-field model to the limiting Hele-Shaw dynamics. In particular, the convergence appears to be slower for high viscosity contrasts.

Interface dynamics in Hele-Shaw flows with centrifugal forces. Preventing cusp singularities with rotation

A class of exact solutions of Hele-Shaw flows without surface tension in a rotating cell is reported. We show that the interplay between injection and rotation modifies the scenario of formation of finite-time cusp singularities. For a subclass of solutions, we show that, for any given initial condition, there exists a critical rotation rate above which cusp formation is suppressed. We also find an exact sufficient condition to avoid cusps simultaneously for all initial conditions within the above subclass.

Langevin approach to generate synthetic turbulent flows

We present an analytical scheme, easily implemented numerically, to generate synthetic Gaussian turbulent flows by using a linear Langevin equation, where the noise term acts as a stochastic stirring force. The characteristic parameters of the velocity field are well introduced, in particular the kinematic viscosity and the spectrum of energy. As an application, the diffusion of a passive scalar is studied for two different energy spectra. Numerical results are compared favorably with analytical calculations.