5,146 research outputs found

    The Impact of the 1996 SSI Childhood Disability Reforms: Evidence from Matched SIPP-SSA Data

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    The Personal Responsibility and Work Opportunity Reconciliation Act of 1996 changed the definition of disability used to determine eligibility for disabled children under the Supplemental Security Income (SSI) program and made other changes in the program. The law required the redetermination of eligibility status for children potentially affected by the new definition of disability. As a result, an estimated 100,000 children were expected to lose SSI benefits. The goal of this paper is to understand the impact of benefit loss on affected children and their families. The analysis draws on data from the 1992, 1993 and 1996 panels of the Survey of Income and Program Participation matched with Social Security Administration records on SSI program participation. The data are used to analyze the impact of the loss of SSI income as a result of the 1996 legislation on family labor supply, welfare program participation, and income and poverty. Compared with families that lost SSI benefits due to normal attrition from the program, the excess benefit loss due to the 1996 childhood disability reforms is associated with lower levels of family labor supply, higher levels of participation in AFDC/TANF and food stamps, and lower levels of family income relative to poverty. For some outcomes, these effects—measured one month after benefit loss—persist for up to 12 months.

    Welfare Reform and Immigrant Participation in the Supplemental Security Income Program

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    We examine the effect of the 1996 welfare reform legislation on participation in the Supplemental Security Income (SSI) program by immigrants. Although none of the immigrants on the SSI rolls before welfare reform lost eligibility, the potential exists for future impacts on the SSI caseload and the well-being of recent immigrants. We use microdata files from the Social Security Administration’s Continuous Work History Sample matched to administrative data on SSI participation for the period 1993 to 1999. We estimate simple models of SSI participation and compare our results to the existing literature. We then estimate a series of difference-in-differences models of SSI participation. These models compare SSI participation by immigrants relative to nativeborn individuals, and among affected immigrants relative to unaffected immigrants and native-born individuals, before and after welfare reform. Descriptive results indicate that the percentage of immigrants and natives receiving SSI decreased after welfare reform, but by a larger percentage for natives than for immigrants. The probability of SSI participation decreased after welfare reform for immigrants who were affected by the legislation relative to immigrants who were unaffected. The difference-in-differences estimate is positive for immigrants relative to otherwise similar natives, but the estimated effect among affected immigrants is about half as large as the effect for unaffected immigrants. When the sample is limited to low earners as a proxy for the SSI means test, the results are qualitatively unchanged but quantitatively much stronger. Authors’ Acknowledgements We are grateful to Ulyses Balderas for assisting with the collection of some data used here. A previous version of this paper was presented at the 2004 Western Regional Science Association Annual Meeting, February 25-28, 2004, Maui, HI.

    Factors Influencing Employment in the U.S. Automobile Industry

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    During the 1980s, increased attention was paid by the united Auto Workers union and politicians to the U.S. automobile industry and the problems it was facing from Japanese competition. Now, with 1992 being a presidential election year, the candidates are continuing to draw attention to what they see as the problems of the U.S. auto industry. And this concern is not without reason. The share of the u.s. market held by the Big Three domestic producers (GM, Ford, and Chrysler), has decreased dramatically over the past three decades. As is shown in Figure 1, the market share of u.s. based producers has fallen from a high of 95.11% in 1962, to around 82% in the mid-1970S, to a low of around 64% in 1987 (MVMA World Motor Vehicle Data, 1990). These figures become even more alarming if we look at the market share of foreign transplants (i.e. foreign auto production plants in the U.S.) and imports taken together. They accounted for 41% of the market in 1990 (Singleton, 1992, p.22)

    The structure of classical extensions of quantum probability theory

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    On the basis of a suggestive definition of a classical extension of quantum mechanics in terms of statistical models, we prove that every such classical extension is essentially given by the so-called Misra–Bugajski reduction map. We consider how this map enables one to understand quantum mechanics as a reduced classical statistical theory on the projective Hilbert space as phase space and discuss features of the induced hidden-variable model. Moreover, some relevant technical results on the topology and Borel structure of the projective Hilbert space are reviewed

    The size, concentration, and growth of biodiversity-conservation nonprofits

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    Nonprofit organizations play a critical role in efforts to conserve biodiversity. Their success in this regard will be determined in part by how effectively individual nonprofits and the sector as a whole are structured. One of the most fundamental questions about an organization’s structure is how large it should be, with the logical counterpart being how concentrated the whole sector should be. We review empirical patterns in the size, concentration, and growth of over 1700 biodiversity-conservation nonprofits registered for tax purposes in the United States within the context of relevant economic theory. Conservation-nonprofit sizes vary by six to seven orders of magnitude and are positively skewed. Larger nonprofits access more revenue streams and hold more of their assets in land and buildings than smaller or midsized nonprofits do. The size of conservation nonprofits varies with the ecological focus of the organization, but the growth rates of nonprofits do not

    Strain Modulated Electronic Properties of Ge Nanowires - A First Principles Study

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    We used density-functional theory based first principles simulations to study the effects of uniaxial strain and quantum confinement on the electronic properties of germanium nanowires along the [110] direction, such as the energy gap and the effective masses of the electron and hole. The diameters of the nanowires being studied are up to 50 {\AA}. As shown in our calculations, the Ge [110] nanowires possess a direct band gap, in contrast to the nature of an indirect band gap in bulk. We discovered that the band gap and the effective masses of charge carries can be modulated by applying uniaxial strain to the nanowires. These strain modulations are size-dependent. For a smaller wire (~ 12 {\AA}), the band gap is almost a linear function of strain; compressive strain increases the gap while tensile strain reduces the gap. For a larger wire (20 {\AA} - 50 {\AA}), the variation of the band gap with respect to strain shows nearly parabolic behavior: compressive strain beyond -1% also reduces the gap. In addition, our studies showed that strain affects effective masses of the electron and hole very differently. The effective mass of the hole increases with a tensile strain while the effective mass of the electron increases with a compressive strain. Our results suggested both strain and size can be used to tune the band structures of nanowires, which may help in design of future nano-electronic devices. We also discussed our results by applying the tight-binding model.Comment: 1 table, 8 figure

    The Algorithmic Origins of Life

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    Although it has been notoriously difficult to pin down precisely what it is that makes life so distinctive and remarkable, there is general agreement that its informational aspect is one key property, perhaps the key property. The unique informational narrative of living systems suggests that life may be characterized by context-dependent causal influences, and in particular, that top-down (or downward) causation -- where higher-levels influence and constrain the dynamics of lower-levels in organizational hierarchies -- may be a major contributor to the hierarchal structure of living systems. Here we propose that the origin of life may correspond to a physical transition associated with a shift in causal structure, where information gains direct, and context-dependent causal efficacy over the matter it is instantiated in. Such a transition may be akin to more traditional physical transitions (e.g. thermodynamic phase transitions), with the crucial distinction that determining which phase (non-life or life) a given system is in requires dynamical information and therefore can only be inferred by identifying causal architecture. We discuss some potential novel research directions based on this hypothesis, including potential measures of such a transition that may be amenable to laboratory study, and how the proposed mechanism corresponds to the onset of the unique mode of (algorithmic) information processing characteristic of living systems.Comment: 13 pages, 1 tabl

    A Deep Multicolor Survey. VI. Near-Infrared Observations, Selection Effects, and Number Counts

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    I present near-infrared J (1.25um), H (1.65um), and K (2.2um) imaging observations of 185 square arcminutes in 21 high galactic latitude fields. These observations reach limiting magnitudes of J ~ 21 mag, H ~ 20 mag and K ~ 18.5 mag. The detection efficiency, photometric accuracy and selection biases as a function of integrated object brightness, size, and profile shape are quantified in detail. I evaluate several popular methods for measuring the integrated light of faint galaxies and show that only aperture magnitudes provide an unbiased measure of the integrated light that is independent of apparent magnitude. These J, H, and K counts and near-infrared colors are in best agreement with passive galaxy formation models with at most a small amount of merging (for Omega_M = 0.3, Omega_Lambda = 0.7).Comment: AJ Accepted (Feb 2001). 28 pages, 7 embedded ps figures, AASTEX5. Minor changes to submitted version. Also available at http://www.astronomy.ohio-state.edu/~martini/pubs

    Beyond shareholder primacy? Reflections on the trajectory of UK corporate governance.

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    Core institutions of UK corporate governance, in particular the City Code on Takeovers and Mergers, the Combined Code on Corporate Governance and the law on directors’ duties, are strongly orientated towards the norm of shareholder primacy. Beyond the core, however, stakeholder interests are better represented, in particular at the intersection of insolvency and employment law. This reflects the influence of European Community laws on information and consultation of employees. In addition, there are signs that some institutional shareholders are redirecting their investment strategies, under government encouragement, away from a focus on short-term returns, in such a way as to favour stakeholder-inclusive practices by firms. On this basis we suggest that the UK system is currently in a state of flux and that the debate over shareholder primacy has not been concluded
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