12,548 research outputs found
The Changing Economic Status of U.S. Disabled Men: Trends and Their Determinants, 1982–1991
In this paper, we track the level of economic well-being of the population of men who began receiving Social Security Disability Insurance (SSDI) benefits in 1980–81 from the time just after they became beneficiaries (in 1982) to 1991, nearly a decade later. We present measures of the economic well-being of disabled individuals and their nondisabled peers as indicators of the relative economic position of these two groups. These measures also provide an intertemporal comparison of well-being and hardship as disabled persons and their nondisabled peers age and retire. We first show several economic well-being indicators for this group of new male recipients of disability benefits in 1982 and 1991. Then, we compare their economic position to that of a matched group of nondisabled males with sufficient work histories to have been disability-insured, that is, eligible for SSDI benefits had they been unable to engage in substantial gainful employment. Because labor market changes over this decade have led to a relative deterioration in the position of younger and less-educated workers, we compare men with disabilities to those without disabilities and distinguish different age and educational levels within the groups. In studying these comparative trends in well-being, we focus on the prevalence of poverty and its correlates. We conclude by assessing the antipoverty effectiveness of Social Security income support for both younger and older men who became SSDI recipients in 1980–81.
The Changing Economic Status of Disabled Women, 1982–1991: Trends and Their Determinants
This study provides an assessment of the intertemporal economic well-being of a representative sample of women who began receiving Social Security Disability Insurance (SSDI) in 1980–81. We compare their economic circumstances over the 1982–1991 period with those of disabled men who also began receiving SSDI in those years and with those of a matched sample of nondisabled women who had sufficient work experience for benefit eligibility should they have become disabled. In 1982, the new SSDI women beneficiaries were a relatively poor segment of U.S. society: one quarter of them lived in poverty and 48 percent had incomes below 150 percent of the poverty line. As of 1991, over one-half of these disabled women lived in families with income below 150 percent of the poverty line. Social Security benefits to disabled women have played an important, and growing, role in sustaining economic status. Nevertheless, the level of well-being of these women lies substantially below that of the comparison groups. We statistically relate the poverty status of these new female recipients to sociodemographic factors that would be expected to contribute to lower levels of well-being, and we simulate the effect of Social Security benefits in reducing poverty and replacing earnings. We suggest a number of SSDI-related policy changes that could, at low cost, reduce poverty among the poorest women.
Do Teens Make Rational Choices? The Case of Teen Nonmarital Childbearing
With emphasis on the role of economic incentives, we explore the determinants of a woman’s choice of whether or not to give birth as an unmarried teenager. Our data are taken from the Panel Study of Income Dynamics. Guided by a simple utility-maximization model, we represent the income possibilities available to teenaged women if they do and do not give birth out of wedlock. We estimate these choice-conditioned income possibilities through a two-stage probit procedure, relying on the observed incomes of a secondary sample of somewhat older women. The response of the young women in our primary sample to these income expectations is measured after controlling for the effects of a variety of other factors, including the characteristics of the girl’s family, the social and economic environment in which she lives (including such policy-related factors as expenditures by states on family planning programs and education), and her own prior choices. We use the estimated structural parameters from our model to simulate the effects of a variety of policy interventions on the probability of becoming an unmarried teen mother. Our estimations provide evidence that income expectations have a persistent influence on the childbearing decision. They also provide evidence that the provision of public family planning expenditures and increases in parental education could reduce the prevalence of teen nonmarital births.
Experimental Studies of the NaCs 53Π0 and a3Σ+ States
We report high resolution measurements of 372 NaCs 53Π0(v, J) ro-vibrational level energies in the range 0 ≤ v ≤ 22. The data have been used to construct NaCs 53Π0 potential energy curves using the Rydberg–Klein-Rees and inverted perturbation approximation methods. Bound-free 53Π0(v, J) → 1(a)3Σ+ emission has also been measured, and is used to determine the repulsive wall of the 1(a)3Σ+ state and the 53Π0 → 1(a)3Σ+ relative transition dipole moment function. Hyperfine structure in the 53Π0 state has not been observed in this experiment. This null result is explained using a simple vector coupling model
Comparing Segmentation by Time and by Motion in Visual Search: An fMRI Investigation
Abstract
Brain activity was recorded while participants engaged in a difficult visual search task for a target defined by the spatial configuration of its component elements. The search displays were segmented by time (a preview then a search display), by motion, or were unsegmented. A preparatory network showed activity to the preview display, in the time but not in the motion segmentation condition. A region of the precuneus showed (i) higher activation when displays were segmented by time or by motion, and (ii) correlated activity with larger segmentation benefits behaviorally, regardless of the cue. Additionally, the results revealed that success in temporal segmentation was correlated with reduced activation in early visual areas, including V1. The results depict partially overlapping brain networks for segmentation in search by time and motion, with both cue-independent and cue-specific mechanisms.</jats:p
Plasmas in Saturn's magnetosphere
The solar wind plasma analyzer on board Pioneer 2 provides first observations of low-energy positive ions in the magnetosphere of Saturn. Measurable intensities of ions within the energy-per-unit charge (E/Q) range 100 eV to 8 keV are present over the planetocentric radial distance range about 4 to 16 R sub S in the dayside magnetosphere. The plasmas are found to be rigidly corotating with the planet out to distances of at least 10 R sub S. At radial distances beyond 10 R sub S, the bulk flows appear to be in the corotation direction but with lesser speeds than those expected from rigid corotation. At radial distances beyond the orbit of Rhea at 8.8 R sub S, the dominant ions are most likely protons and the corresponding typical densities and temperatures are 0.5/cu cm and 1,000,000 K, respectively, with substantial fluctuations. It is concluded that the most likely source of these plasmas in the photodissociation of water frost on the surface of the ring material with subsequent ionization of the products and radially outward diffusion. The presence of this plasma torus is expected to have a large influence on the dynamics of Saturn's magnetosphere since the pressure ratio beta of these plasmas approaches unity at radial distances as close to the planet as 6.5 R sub S. On the basis of these observational evidences it is anticipated that quasi-periodic outward flows of plasma, accompanied with a reconfiguration of the magnetosphere beyond about 6.5 R sub S, will occur in the local night sector in order to relieve the plasma pressure from accretion of plasma from the rings
Borazineâ CF3â Adducts for Rapid, Room Temperature, and Broad Scope Trifluoromethylation
A fluoroformâ derived borazine CF3â transfer reagent is used to effect rapid nucleophilic reactions in the absence of additives, within minutes at 25â °C. Inorganic electrophiles spanning seven groups of the periodic table can be trifluoromethylated in high yield, including transition metals used for catalytic trifluoromethylation. Organic electrophiles included (hetero)arenes, enabling Câ H and Câ X trifluoromethylation reactions. Mechanistic analysis supports a dissociative mechanism for CF3â transfer, and cation modification afforded a reagent with enhanced stability.Von Fluoroform abgeleitet wurde ein stabiles Reagenz für nukleophile Trifluormethylierungen anorganischer und organischer Elektrophile (E) bei Raumtemperatur. Das Reaktionsspektrum umfasst 18 anorganische Elemente, nucleophile aromatische Substitutionen sowie CF3â â Additionen an Carbonylverbindungen und Imine. Kinetische Studien sprechen für einen dissoziativen Mechanismus.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141871/1/ange201711316-sup-0001-misc_information.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141871/2/ange201711316.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141871/3/ange201711316_am.pd
Borazineâ CF3â Adducts for Rapid, Room Temperature, and Broad Scope Trifluoromethylation
A fluoroformâ derived borazine CF3â transfer reagent is used to effect rapid nucleophilic reactions in the absence of additives, within minutes at 25â °C. Inorganic electrophiles spanning seven groups of the periodic table can be trifluoromethylated in high yield, including transition metals used for catalytic trifluoromethylation. Organic electrophiles included (hetero)arenes, enabling Câ H and Câ X trifluoromethylation reactions. Mechanistic analysis supports a dissociative mechanism for CF3â transfer, and cation modification afforded a reagent with enhanced stability.A trifluoromethylating matter: A stable fluoroformâ derived reagent facilitates the nucleophilic trifluoromethylation of a broad array of inorganic and organic electrophiles (E) at room temperature. The reaction scope includes 18 inorganic elements, nucleophilic aromatic substitution, and CF3â addition to carbonyl and imine compounds. Kinetic analysis supports a dissociative mechanism.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141342/1/anie201711316_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141342/2/anie201711316.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141342/3/anie201711316-sup-0001-misc_information.pd
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