Job Polarization in the U.S.: A Reassessment of the Evidence from the 1980s and 1990s

In this paper, we review the evidence for job polarization in the U.S. and provide a description of the occupational employment changes that characterized the U.S. labor market during the 1970s, 1980s, and 1990s. We begin by replicating the existing job polarization trends, which are produced using a modified occupational coding scheme intended to make occupational categories comparable over time. Using two alternative procedures to obtain consistent occupational codes across decades, we show that the finding that jobs polarized in the 1990s relative to the 1980s no longer holds. Instead, we find that occupational employment shifts were very similar during the two decades. In addition, we demonstrate that the method used to rank occupations according to their skill content has a substantial impact on the employment growth in low-skill job categories. Finally, using an additional occupational crosswalk that allows us to obtain consistent occupational categories from 1970 to 2002, we provide evidence in favor of a long-term trend towards employment growth in high-skill jobs and employment decline in some middle-skill jobs, but no sharp contrast between the 1980s and the 1990s. Our findings suggest that the evolution of the occupational employment structure and the divergent wage growth patterns observed during the 1980s and 1990s do not easily fit within the routinization story as usually told.Job Polarization, Occupational Employment, Employment Growth, Wage Inequality

Financial spillovers from the US financial markets to the emerging markets during the subprime crisis: the example of Indian equity markets

This paper provides evidence of spillover effects from the Indian to the US financial markets. We use VAR and Kalman filter analysis to assess the influence of financial stress indicators like the LIBOR-OIS, CDS, the S&P 500 volatility and the exchange rate of the rupee against the Dollar on two indicators of financial stress in India, namely the illiquidity of stock indices and their volatility. We conduct an analysis bases on both daily and monthly frequency and use a database that consists of both aggregate and disaggregated indexes. Our results points to a signification contagion effect after the period following the Lehman Brothers collapse.Subprime crisis, Emerging Markets, VAR analysis, financial stress

Spill-Overs from Good Jobs

Does attracting or losing jobs in high paying sectors have important spill-over effects on wages in other sectors? The answer to this question is central to a proper assessment of many trade and industrial policies. In this paper, we explore this question by examining how predictable changes in industrial composition in favor of high paying sectors affect wage determination at the industry-city level. In particular, we use US Census data over the years 1970 to 2000 to quantify the relationship between changes in industry-specific city-level wages and changes in industrial composition. Our finding is that the spill-over (i.e., general equilibrium) effects associated with changes in the fraction of jobs in high paying sectors are very substantial and persistent. Our point estimates indicate that the total effect on average wages of a change in industrial composition that favors high paying sectors is about 3.5 times greater than that obtained from a commonly used composition-adjustment approach which neglects general equilibrium effects. We interpret our results as being most likely driven by a variant of the mechanism recently emphasized in the heterogenous firm literature whereby changes in competitive pressure cause a reallocation of employment toward the most efficient firms.

Wide Band Propagation in Train-to-Train Scenarios - Measurement Campaign and First Results

Within the next decades the railway systems will change to fully autonomous high speed trains (HSTs). An increase in efficiency and safety and a reduction of costs would go hand in hand. Today’s centralized railway management system and established regulations can not cope with trains driving within the absolute braking distance as it would be necessary for electronic coupling or platooning maneuvers. Hence, to ensure safety and reliability, new applications and changes in the train control and management are necessary. Such changes demand new reliable control communication links between train-to-train (T2T) and future developments on train-to-ground (T2G). T2G will be covered by long term evolution-railway (LTE-R) which shall replace today’s global system for mobile communications-railway (GSM-R). The decentralized T2T communication is hardly investigated and no technology has been selected. This publication focuses on the wide band propagation for T2T scenarios and describes a extensive channel sounding measurement campaign with two HSTs. First results of T2T communication at high speed conditions in different environments are presented

Bayesian Cramér-Rao Lower Bound for Magnetic Field-Based Localization

In this paper, we show how to analyze the achievable position accuracy of magnetic localization based on Bayesian Cramér-Rao lower bounds and how to account for deterministic inputs in the bound. The derivation of the bound requires an analytical model, e.g., a map or database, that links the position that is to be estimated to the corresponding magnetic field value. Unfortunately, finding an analytical model from the laws of physics is not feasible due to the complexity of the involved differential equations and the required knowledge about the environment. In this paper, we therefore use a Gaussian process (GP) that approximates the true analytical model based on training data. The GP ensures a smooth, differentiable likelihood and allows a strict Bayesian treatment of the estimation problem. Based on a novel set of measurements recorded in an indoor environment, the bound is evaluated for different sensor heights and is compared to the mean squared error of a particle filter. Furthermore, the bound is calculated for the case when only the magnetic magnitude is used for positioning and the case when the whole vector field is considered. For both cases, the resulting position bound is below 10cm indicating an high potential accuracy of magnetic localization

Strong lensing in the MareNostrum Universe: biases in the cluster lens population

Strong lensing is one of the most direct probes of the mass distribution in the inner regions of galaxy clusters. It can be used to constrain the density profiles and to measure the mass of the lenses. Moreover, the abundance of strong lensing events can be used to constrain the structure formation and the cosmological parameters through the so-called "arc-statistics" approach. However, several issues related to the usage of strong lensing clusters in cosmological applications are still controversial, leading to the suspect that several biases may affect this very peculiar class of objects. With this study we aim at better understanding the properties of galaxy clusters which can potentially act as strong lenses. We do so by investigating the properties of a large sample of galaxy clusters extracted from the N-body/hydrodynamical simulation MareNostrum Universe. We explore the correlation between the cross section for lensing and many properties of clusters, like the mass, the three-dimensional and projected shapes, their concentrations, the X-ray luminosity and the dynamical activity. We find that the probability of strong alignments between the major axes of the lenses and the line of sight is a growing function of the lensing cross section. In projection, the strong lenses appear rounder within R200, but we find that their cores tend to be more elliptical as the lensing cross section increases. We also find that the cluster concentrations estimated from the projected density profiles tend to be biased high. The X-ray luminosity of strong lensing clusters is higher than that of normal lenses of similar mass and redshift. This is particular significant for the least massive lenses. Finally, we find that the strongest lenses generally exhibit an excess of kinetic energy within the virial radius, indicating that they are more dynamically active than usual clusters.Comment: 22 pages, 18 figures, accepted for publication on A&