The Effects of Welfare and Tax Reform: The Material Well-Being of Single Mothers in the 1980s and 1990s

The tax and welfare programs that provide income and in-kind benefits to single mothers have changed dramatically in recent years. These changes began as far back as the mid-1980s and culminated with the 1996 welfare law that 'ended welfare as we knew it.' These tax and welfare changes have sharply increased the employment of single mothers and cut welfare rolls. However, little is know about the effects of these policy changes on the living conditions of single mothers and their children. Studies of those leaving welfare have found that a substantial percentage have problems paying rent, purchasing enough food, and paying utility bills. Other studies have found a decline in income among the worst-off single mothers. The goal of this paper is to examine the material well-being of single mothers and their families before and soon after welfare reform. Using data from two nationally representative household surveys we examine the consumption patterns of single mothers and their families. We find that the material conditions of single mothers did not decline in recent years, either in absolute terms or relative to single childless women or married mothers. In most cases, our evidence suggests that the material conditions of single mothers have improved slightly, even for highly disadvantaged single mothers.

Further Results on Measuring the Well-Being of the Poor Using Income and Consumption

In the U.S., analyses of poverty rates and the effects of anti-poverty programs rely almost exclusively on income data. In earlier work (Meyer and Sullivan, 2003) we emphasized that conceptual arguments generally favor using consumption data to measure the well-being of the poor, and, on balance, data quality issues favor consumption in the case of single mothers. Our earlier work did not show that income and consumption differ in practice. Here we further examine data quality issues and show that important conclusions about recent trends depend on whether one uses consumption or income. Changes in the distribution of resources for single mothers differ sharply in recent years depending on whether measured by income or consumption. Measures of overall and sub-group poverty also sharply differ. In addition to examining broader populations and a longer time period, we also consider new dimensions of data quality such as survey and item nonresponse, imputation, and precision. Finally, we demonstrate the flaws in a recent paper that compares income and consumption data.

Quark fragmentation functions in a diquark model for proton and Λ\Lambda hyperon production

A simple quark-diquark model for nucleon and $\Lambda$ structure is used to calculate leading twist light-cone fragmentation functions for a quark to inclusively decay into P or $\Lambda$. The parameters of the model are determined by fitting to the known deep-inelastic structure functions of the nucleon. When evolved from the initial to the final $Q^2$ scale, the calculated fragmentation functions are in remarkable agreement (for $z>0.4$) with those extracted from partially inclusive $ep$ and $e^+ e^-$ experiments at high energies. Predictions are made, using no additional parameters, for longitudinally and transversely polarized quarks to fragment into p or $\Lambda$.Comment: 15 pages, latex, figures may be obtained by writing to hafsa%png-qau%[email protected]

Coping with the cold: Space heating and the urban poor in developing countries

10.1016/j.eneco.2004.04.011Energy Economics263345-357EECO

Nonlinear electrical properties of grain boundaries in oxygen ion conductors - Modeling the varistor behavior

We report on numerical simulations of the grain-boundary varistor behavior recently observed in Y2O3-doped CeO2 of high purity. The aim of this study is to disclose the nature of the nonlinear electrical properties of the grain boundaries in oxygen ion conductors. Under small voltages (< 25 mV), the simulation shows a linear current-voltage relation dominated by the grain-boundary resistance. Under intermediate voltages (25-200 mV), the simulation discloses a grain-boundary resistance breakdown and a nonlinear current-voltage relation. The increase of ionic charge carriers in the grain-boundary space-charge layer is the cause for the nonlinear behavior. Calculations are compared to experimental results. (c) 2005 The Electrochemical Society

Accelerating Bayesian inference for evolutionary biology models.

Bayesian inference is widely used nowadays and relies largely on Markov chain Monte Carlo (MCMC) methods. Evolutionary biology has greatly benefited from the developments of MCMC methods, but the design of more complex and realistic models and the ever growing availability of novel data is pushing the limits of the current use of these methods. We present a parallel Metropolis-Hastings (M-H) framework built with a novel combination of enhancements aimed towards parameter-rich and complex models. We show on a parameter-rich macroevolutionary model increases of the sampling speed up to 35 times with 32 processors when compared to a sequential M-H process. More importantly, our framework achieves up to a twentyfold faster convergence to estimate the posterior probability of phylogenetic trees using 32 processors when compared to the well-known software MrBayes for Bayesian inference of phylogenetic trees. https://bitbucket.org/XavMeyer/hogan. [email protected]. Supplementary data are available at Bioinformatics online

Integrating process design and control: An application of optimal control to chemical processes

In this paper, the optimal design of process systems generically used in chemical industries is studied. The closely coupled nature of optimal design specification of the equipment, the determination of the optimal process parameters in steady-state, moreover, some issues of the application of optimal control is shown. The solution of the overall optimization problem including (i) optimal design of the equipment and (ii) specification of its optimal control strategy can be found relying on two different design concepts, namely, on the conventionally used sequential or, on the newly emerged simultaneous design approaches. This paper gives the theoretical background of the ideas and presents a comparative summary of the approaches. The two approaches are contrasted to each other in which the effects of the interaction of optimal process design and optimal control is highlighted. A new simultaneous optimization procedure providing economic and operability benefits over the traditional stand-alone approach is proposed. The applicability of the idea is demonstrated by means of a design study carried out for optimal design of a coaxial heat exchanger and a reactive distillation column for the synthesis of ethyl tert butyl ether (ETBE), relying on the benefits of the utilization of optimal control

Solid H\u3csub\u3e2\u3c/sub\u3e and D\u3csub\u3e2\u3c/sub\u3e: Remarkable Differences in Some NMR Properties

The differences in the observed properties of solid H2 and D2 are reviewed, and in particular those encountered in NMR experiments. The failure to detect a sharp NMR (I=1) impurity ‘‘isolated pair’’ spectrum in p-D2 is discussed in terms of a larger crystalline field than in H2, where an intense and sharp pair spectrum has been observed. Furthermore, we discuss the dramatic (I=1) solid echo signal loss with decreasing temperature which is observed in solid D2, but not for solid H2. A theory of the solid echo damping through orientational fluctuations is developed. This theory accounts for the observed solid echo decay in D2 as a function of the pulse spacing time τ and leads to an estimation of the order parameter fluctuation amplitude and the correlation time τc. However, the theory cannot account for the loss of spin (as determined from Curie’s law), which must occur for very small values of τ that are not covered by the theory