Liquid-core capsules have wide-ranging applications in the high-efficiency encapsulation and controlled release of drugs, dyes, enzymes, and other substrates. Their great utility has driven the rapid development of various preparation techniques. However, there remains no convenient technique for the preparation of submicrometer liquid-core capsules with shell thicknesses less than 100 nm. Here, we demonstrate a new interfacial free-radical polymerization approach for the straightforward preparation of liquid-core polymer capsules. Conceptually, this interfacial free-radical polymerization is analogous to the classical "nylon rope trick" wherein hydrophobic and hydrophilic monomers alternately copolymerize to constrain the polymerization at interfaces, but its free-radical mechanism allows precise control of initiation, which makes it possible to finely disperse the immiscible phases prior to polymerization.

This paper employs a hazard model to analyse the impact of education and two types of prison employment programmes on recidivism over a ten-year period for 4515 prisoners released from Ohio prisons in 1992. Estimations with a Weibull mixture model and propensity score approach provide two means for investigating self-selection bias. Selection bias is detected for participation in the most common prison job programme but has little effect on estimated marginal savings impacts of prison industry and education programmes. Estimates of the cost savings from postponing return to prison due to programme participation are provided. The potential for cost savings through decreasing or delaying return to prison is an important finding given the substantial and increasing cost of incarceration. Copyright (c) The London School of Economics and Political Science 2008.

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Income taxes vary significantly across states. Typical measures of these variations utilize aggregate measures, such as per capita taxes or taxes per thousand dollars of income. In this article the income tax systems, as opposed to the taxes paid, are described and compared for the various states. It is demonstrated that the diversity in the treatment of individuals for income tax purposes is vast. We propose that analysis of state taxation and its effect on individuals and businesses be conducted on a disaggregated basis.The era of state taxation of personal income was ushered in with the Wisconsin progressive income tax of 1911.Since then the income tax has grown both in popularity and importance. Currently, 40 states levy a comprehensive income tax with a total revenue contribution second only to that of sales taxes. In addition, the recent trend has been toward even greater reliance on income taxation as the growth of income tax receipts outstripped most other sources of state funding (see Gold, 1983). Although this development has been hailed for altering the predominantly regressive state revenue systems (Rock, 1983), income taxes present problems for the analyst and policymaker alike.Unlike sales or property taxes, the income tax allows great diversity in implementation. Variations among state income tax AUTHORS' NOTE: We wish to thank the Marquette University Department of Economics semmar group and an anonymous referee for helpful suggestions. Any remaining errors are, of course, our own.

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