What should an index of school segregation measure?

The article aims to make a methodological contribution to the education segregation literature, providing a critique of previous measures of segregation used in the literature, as well as suggesting an alternative approach to measuring segregation. Specifically, the paper examines Gorard, Fitz and Taylor's finding that social segregation between schools, as measured by free school meals (FSM) entitlement, fell significantly in the years following the 1988 Education Reform Act. Using Annual Schools Census data from 1989 to 2004, the paper challenges the magnitude of their findings, suggesting that the method used by Gorard et al. seriously overstates the size of the fall in segregation. We make the case for a segregation curve approach to measuring segregation, where comparisons of the level of segregation are possible regardless of the percentage FSM eligibility. Using this approach, we develop a new method for describing both the level and the location of school segregation

Female participation increases and gender segregation. ESRI WP564, May 2017

This article examines the impact of a large increase in female participation on occupational segregation. Increases in female participation may decrease occupational segregation if women enter male dominated sectors but may increase segregation if they enter already female dominated sectors. Using Ireland as a test case due to the recent large increase in female participation rates, we firstly carry out a decomposition analysis between 1991 and 2006 and find that the rise in female employment was driven predominantly by increased demand while between one tenth and one fifth of the rise was due to women increasing their share of occupational employment. Formal measures of segregation show that occupational segregation fell over this time period. The formal measures of segregation show that the level of occupational grouping is important with stagnation or smaller falls in segregation using a broad occupational grouping and sharper falls using a more detailed occupational grouping. Our findings support previous U.S. research that found a rise in female participation resulted in a decline in occupational segregation

Quantifying the Energetics and Length Scales of Carbon Segregation to Fe Symmetric Tilt Grain Boundaries Using Atomistic Simulations

Segregation of impurities to grain boundaries plays an important role in both the stability and macroscopic behavior of polycrystalline materials. The research objective in this work is to better characterize the energetics and length scales involved with the process of solute and impurity segregation to grain boundaries. Molecular dynamics simulations are used to calculate the segregation energies for carbon within multiple grain boundary sites over a database of 125 symmetric tilt grain boundaries in Fe. The simulation results show that the majority of atomic sites near the grain boundary have segregation energies lower than in the bulk. Moreover, depending on the boundary, the segregation energies approach the bulk value approximately 5-12 \AA\ away from the center of the grain boundary, providing an energetic length scale for carbon segregation. A subsequent data reduction and statistical representation of this dataset provides critical information such as about the mean segregation energy and the associated energy distributions for carbon atoms as a function of distance from the grain boundary, which quantitatively informs higher scale models with energetics and length scales necessary for capturing the segregation behavior of impurities in Fe. The significance of this research is the development of a methodology capable of ascertaining segregation energies over a wide range of grain boundary character (typical of that observed in polycrystalline materials), which herein has been applied to carbon segregation in a specific class of grain boundaries in iron

The Divergence Index: A Decomposable Measure of Segregation and Inequality

Decomposition analysis is a critical tool for understanding the social and spatial dimensions of inequality, segregation, and diversity. In this paper, I propose a new measure - the Divergence Index - to address the need for a decomposable measure of segregation. Although the Information Theory Index has been used to decompose segregation within and between communities, I argue that it measures relative diversity not segregation. I demonstrate the importance of this conceptual distinction with two empirical analyses: I decompose segregation and relative homogeneity in the Detroit metropolitan area, and I analyze the relationship between the indexes in the 100 largest U.S. cities. I show that it is problematic to interpret the Information Theory Index as a measure of segregation, especially when analyzing local-level results or any decomposition of overall results. Segregation and diversity are important aspects of residential differentiation, and it is critical that we study each concept as the structure and stratification of the U.S. population becomes more complex

Segregation by thermal diffusion in granular shear flows

Segregation by thermal diffusion of an intruder immersed in a sheared granular gas is analyzed from the (inelastic) Boltzmann equation. Segregation is induced by the presence of a temperature gradient orthogonal to the shear flow plane and parallel to gravity. We show that, like in analogous systems without shear, the segregation criterion yields a transition between upwards segregation and downwards segregation. The form of the phase diagrams is illustrated in detail showing that they depend sensitively on the value of gravity relative to the thermal gradient. Two specific situations are considered: i) absence of gravity, and ii) homogeneous temperature. We find that both mechanisms (upwards and downwards segregation) are stronger and more clearly separated when compared with segregation criteria in systems without shear.Comment: 8 figures. To appear in J. Stat. Mec

Oxygen vacancy segregation and space-charge effects in grain boundaries of dry and hydrated BaZrO3

A space-charge model is applied to describe the equilibrium effects of segregation of double-donor oxygen vacancies to grain boundaries in dry and wet acceptor-doped samples of the perovskite oxide BaZrO3. The grain boundary core vacancy concentrations and electrostatic potential barriers resulting from different vacancy segregation energies are evaluated. Density-functional calculations on vacancy segregation to the mirror-symmetric \Sigma 3 (112) [-110] tilt grain boundary are also presented. Our results indicate that oxygen vacancy segregation can be responsible for the low grain boundary proton conductivity in BaZrO3 reported in the literature