Does Immigration Affect the Phillips Curve? Some Evidence for Spain

The Phillips curve has flattened in Spain over 1995-2006: unemployment has fallen by 15 percentage points, with roughly constant inflation. This change has been more pronounced than elsewhere. We argue that this stems from the immigration boom in Spain over this period. We show that the New Keynesian Phillips curve is shifted by immigration if natives’ and immigrants’ labor supply or bargaining power differ. Estimation of the curve for Spain indicates that the fall in unemployment since 1995 would have led to an annual increase in inflation of 2.5 percentage points if it had not been largely offset by immigration.Phillips curve, immigration

Detecting big structural breaks in large factor models

Constant factor loadings is a standard assumption in the analysis of large dimensional factor models. Yet, this assumption may be restrictive unless parameter shifts are mild. In this paper we develop a new testing procedure to detect big breaks in factor loadings at either known or unknown dates. It is based upon testing for structural breaks in a regression of the first of the ¯r factors estimated by PC for the whole sample on the remaining r−1 factors, where r is chosen using Bai and Ng´s (2002) information criteria. We argue that this test is more powerful than other tests available in the literature on this issue.structural break; large factor model

Wald Tests of I(1) against I(d) alternatives : some new properties and an extension to processes with trending components

This paper analyses the power properties, under fixed alternatives, of a Wald-type test, i.e., the (Efficient) Fractional Dickey-Fuller (EFDF) test of I(1) against I(d), d

Simple Wald tests of the fractional integration parameter : an overview of new results

This paper presents an overview of some new results regarding an easily implementable Wald test-statistic (EFDF test) of the null hypotheses that a time-series process is I(1) or I(0) against fractional I(d) alternatives, with d?(0,1), allowing for unknown deterministic components and serial correlation in the error term. Specifically, we argue that the EFDF test has better power properties under fixed alternatives than other available tests for fractional roots, as well as analyze how to implement this test when the deterministic components or the long-memory parameter are subject to structural breaks.Fractional processes, Deterministic components, Power, Structural breaks

Estimation of Characteristics-based Quantile Factor Models

This paper studies the estimation of characteristic-based quantile factor models where the factor loadings are unknown functions of observed individual characteristics while the idiosyncratic error terms are subject to conditional quantile restrictions. We propose a three-stage estimation procedure that is easily implementable in practice and has nice properties. The convergence rates, the limiting distributions of the estimated factors and loading functions, and a consistent selection criterion for the number of factors at each quantile are derived under general conditions. The proposed estimation methodology is shown to work satisfactorily when: (i) the idiosyncratic errors have heavy tails, (ii) the time dimension of the panel dataset is not large, and (iii) the number of factors exceeds the number of characteristics. Finite sample simulations and an empirical application aimed at estimating the loading functions of the daily returns of a large panel of S\&P500 index securities help illustrate these properties

Improving the Inertial Response of a Grid-Forming Voltage Source Converter

In recent years, the use of synchronous generators (SGs) has been displaced due to the increased use of renewable energy sources. These types of plants mostly use power electronic converters to connect to power grids, which, due to their mode of operation, cannot provide the same services. This paper analyzes the synchronization of Grid-Forming converters (GFM) without phase-locked loop (PLL) through the active power control loop. Stability analysis shows that when increasing the emulated moment of inertia in a voltage source converter (VSC) using grid-forming control, the system becomes oscillatory. The paper proposes a novel compensation mechanism in order to damp the system oscillation, allowing the implementation of inertia emulation. Finally, the real-time implementation is executed using a Hardware in the Loop experimental set-up. The response of VSC under grid disturbances is simulated in a real time simulator, while the proposed control system is implemented in a real-time controller platform

Synthesis and addition of Al-substituted Tobermorite particles to cement pastes

The last generation of cement hydration accelerators relies on the seeding effect induced by amorphous calcium silicate hydrate particles. However, little is known about the effect of variables, such as the degree of crystallinity and morphology, on their performance. In this work, particles with a Ca/(Si+Al) molar ratio of 0.83 and different proportions of aluminum substitution for silicon were synthesized under hydrothermal conditions. X-ray diffractograms, nuclear magnetic resonance spectra, and scanning electron microscopy images showed that this altered the degree of crystallinity, structure, and morphology of the particles. Nevertheless, the addition of the synthesis products to cement pastes and their subsequent study by isothermal calorimetry and mechanical tests showed that the variables with the largest impact on cement hydration are the dosage and the proper dispersion of the particles. In fact, the use of a dispersing agent is highly recommended while drying of the particles should be avoided to prevent irreversible agglomeration processes from taking place