Search results for "convergence"

Last Interglacial Hydroclimate Seasonality Reconstructed From Tropical Atlantic Corals

2018

The seasonality of hydroclimate during past periods of warmer than modern global temperatures is a critical component for understanding future climate change scenarios. Although only partially analogous to these scenarios, the last interglacial (LIG, Marine Isotope Stage 5e, ~127–117 ka) is a popular test bed. We present coral δ18O monthly resolved records from multiple Bonaire (southern Caribbean) fossil corals (Diploria strigosa) that date to between 130 and 118 ka. These records represent up to 37 years and cover a total of 105 years, offering insights into the seasonality and characteristics of LIG tropical Atlantic hydroclimate. Our coral δ18O records and available coral Sr/Ca-sea surf…

Palaeoenvironmental changes in the arid and subarid belt (Sahara-Sahel-Arabian peninsula) from 150 kyr to present

2004

The PEP III Arid to Subarid Belt includes the largest hot desert in the world, the Sahara- Arabian desert and the Sahel zone. The region of interest extends south of the Atlas Mountains and south and east of the Mediterranean Sea to approximately 10 °N and shows a broadly zonal pattern with a varying seasonal distribution of precipitation. In the north (ca. 20–23 °N), rainfall results from the southward displacement of the midlatitude westerlies during winter whereas the south is governed by seasonal northward migration of the Intertropical Convergence Zone (ITCZ). Contraction and expansion phases of these presently semi-arid to hyper-arid desert areas result from significant changes in loc…

PRICE CONVERGENCE IN THE EUROPEAN CAR MARKET

2008

International audience; This paper examines price convergence in the European Union car market over the period 1995-2005. We find that there is a clear evidence of price convergence among the EU15 countries, but not before 1999. Moreover, countries of the Economic and Monetary Union (EMU) started convergence previously to the EU15 as a whole. Finally, exchange rate changes have significantly contributed to price dispersion over time across countries. The results provide significant evidence that trade liberalization and the EMU have enhanced the process of regional integration in the European automobile industry, even though there is room for further measures to promote integration.

Convergence in car prices among European countries

2011

This article contributes to the literature on price convergence in Europe by investigating the existence of stochastic and deterministic convergence of car prices in the EU15 countries. We apply recently developed econometric techniques that allow for multiple structural breaks to an up-to-date dataset. We find considerable evidence of both types of convergence in our sample of countries and car models, therefore suggesting a tendency for relative prices to equalize over time. In addition, we find evidence regarding the importance in this convergence process of both legislative changes taking place in the years 1996 and 2002, and the implementation of Economic and Monetary Union (EMU).

VERTICAL MOTION CHANGES RELATED TO NORTH-EAST BRAZIL RAINFALL VARIABILITY: A GCM SIMULATION

1996

The atmospheric structure over north-east Brazil during anomalous rainfall years is studied in the 11 levels of the outputs of the Laboratoire de Meteorologie Dynamique atmospheric general circulation model (LMD AGCM). Seven 19-year simulations were performed using observed sea-surface temperature (SST) corresponding to the period 1970– 1988. The ensemble mean is calculated for each month of the period, leading to an ensemble-averaged simulation. The simulated March-April rainfall is in good agreement with observations. Correlations of simulated rainfall and three SST indices relative to the equatorial Pacific and northern and southern parts of the Atlantic Ocean exhibit stronger relationsh…

Electronic structure calculations with GPAW: a real-space implementation of the projector augmented-wave method.

2011

Electronic structure calculations have become an indispensable tool in many areas of materials science and quantum chemistry. Even though the Kohn-Sham formulation of the density-functional theory (DFT) simplifies the many-body problem significantly, one is still confronted with several numerical challenges. In this article we present the projector augmented-wave (PAW) method as implemented in the GPAW program package (https://wiki.fysik.dtu.dk/gpaw) using a uniform real-space grid representation of the electronic wavefunctions. Compared to more traditional plane wave or localized basis set approaches, real-space grids offer several advantages, most notably good computational scalability an…

On the convergence of the finite element approximation of eigenfrequencies and eigenvectors to Maxwell's boundary value problem

1981

Stick-slip and convergence of feedback-controlled systems with Coulomb friction

2020

An analysis of stick-slip behavior and convergence of trajectories in the feedback-controlled motion systems with discontinuous Coulomb friction is provided. A closed-form parameter-dependent stiction region, around an invariant equilibrium set, is proved to be always reachable and globally attractive. It is shown that only asymptotic convergence can be achieved, with at least one but mostly an infinite number of consecutive stick-slip cycles, independent of the initial conditions. Theoretical developments are supported by a number of numerical results with dedicated convergence examples.

A general framework for a class of non-linear approximations with applications to image restoration

2018

Este artículo se encuentra disponible en la página web de la revista en la siguiente URL: https://www.sciencedirect.com/science/article/abs/pii/S0377042717301188 Este es el pre-print del siguiente artículo: Candela, V., Falcó, A. & Romero, PD. (2018). A general framework for a class of non-linear approximations with applications to image restoration. Journal of Computational and Applied Mathematics, vol. 330 (mar.), pp. 982-994, que se ha publicado de forma definitiva en https://doi.org/10.1016/j.cam.2017.03.008 This is the pre-peer reviewed version of the following article: Candela, V., Falcó, A. & Romero, PD. (2018). A general framework for a class of non-linear approximations with applic…

A fast heuristic for solving the D1EC coloring problem

2010

In this paper we propose an efficient heuristic for solving the Distance-1 Edge Coloring problem (D1EC) for the on-the-fly assignment of orthogonal wireless channels in wireless as soon as a topology change occurs. The coloring algorithm exploits the simulated annealing paradigm, i.e., a generalization of Monte Carlo methods for solving combinatorial problems. We show that the simulated annealing-based coloring converges fast to a sub optimal coloring scheme even for the case of dynamic channel allocation. However, a stateful implementation of the D1EC scheme is needed in order to speed-up the network coloring upon topology changes. In fact, a stateful D1EC reduces the algorithm’s convergen…