When Do Single Mothers Work? An Analysis of the 1990 Census Data

This study analyzes the relative effect of the amount of public assistance income received one year on the probability that a single mother is employed the following year compared to a variety of other determinants of employment status. The analysis is based on a national sample which was drawn from the Public Use Micro data 5 percent Sample (PUMS) of the 1990 U.S. Census. It consists of the 275,744female householders who were divorced, separated, widowed or never married, and living with their own children age 18 and under. Logistic regression was utilized to calculate the probability of being employed in 1990 according to sources and amounts of income in 1989, level of education, age, work experience, number and age of children, race, and marital status. The results indicate that greater amounts of public assistance income reduced the probability of being employed. However, several other factors-including race-ethnicity, family form and size, educational background and previous earnings-were significant, independent determinants of labor-force status. In particular, African- American women, women with children under six, women with relatively low levels of education and low earnings in the previous year, and nevermarried women all faced a reduced probability of being employed in 1990 regardless of how much public assistance income they received in 1989. The paper concludes with an assessment of the implications of these findings for current debates on the relationships among welfare receipt, work incentives, and employment

The P2X(7 )receptor is a candidate product of murine and human lupus susceptibility loci: a hypothesis and comparison of murine allelic products

Systemic lupus erythematosus and its murine equivalent, modelled in the New Zealand Black and New Zealand White (NZB × NZW)F(1 )hybrid strain, are polygenic inflammatory diseases, probably reflecting an autoimmune response to debris from cells undergoing programmed cell death. Several human and murine loci contributing to disease have been defined. The present study asks whether the proinflammatory purinergic receptor P2X(7), an initiator of a form of programmed cell death known as aponecrosis, is a candidate product of murine and human lupus susceptibility loci. One such locus in (NZB × NZW)F(1 )mice is lbw3, which is situated at the distal end of NZW chromosome 5. We first assess whether NZB mice and NZW mice carry distinct alleles of the P2RX(7 )gene as expressed by common laboratory strains, which differ in sensitivity to ATP stimulation. We then compare the responses of NZB lymphocytes, NZW lymphocytes and (NZB × NZW)F(1 )lymphocytes to P2X(7 )stimulation. NZB and NZW parental strains express the distinct P2X(7)-L and P2X(7)-P alleles of P2RX(7), respectively, while lymphocytes from these and (NZB × NZW)F(1 )mice differ markedly in their responses to P2X(7 )receptor stimulation. NZB mice and NZW mice express functionally distinct alleles of the proinflammatory receptor, P2X(7). We show that current mapping suggests that murine and human P2RX(7 )receptor genes lie within lupus susceptibility loci lbw3 and SLEB4, and we argue that these encode a product with the functional characteristics consistent with a role in lupus. Furthermore, we argue that aponecrosis as induced by P2X(7 )is a cell death mechanism with characteristics that potentially have particular relevance to disease pathogenesis

Abnormal Speech Motor Control in Individuals with 16p11.2 Deletions.

Speech and motor deficits are highly prevalent (>70%) in individuals with the 600 kb BP4-BP5 16p11.2 deletion; however, the mechanisms that drive these deficits are unclear, limiting our ability to target interventions and advance treatment. This study examined fundamental aspects of speech motor control in participants with the 16p11.2 deletion. To assess capacity for control of voice, we examined how accurately and quickly subjects changed the pitch of their voice within a trial to correct for a transient perturbation of the pitch of their auditory feedback. When compared to controls, 16p11.2 deletion carriers show an over-exaggerated pitch compensation response to unpredictable mid-vocalization pitch perturbations. We also examined sensorimotor adaptation of speech by assessing how subjects learned to adapt their sustained productions of formants (speech spectral peak frequencies important for vowel identity), in response to consistent changes in their auditory feedback during vowel production. Deletion carriers show reduced sensorimotor adaptation to sustained vowel identity changes in auditory feedback. These results together suggest that 16p11.2 deletion carriers have fundamental impairments in the basic mechanisms of speech motor control and these impairments may partially explain the deficits in speech and language in these individuals

Thyroid hormones correlate with resting metabolic rate, not daily energy expenditure, in two charadriiform seabirds

K. Woo, M. Le Vaillant, T. van Nus, and especially A. Wesphal, J. Schultner and I. Dorresteijn, assisted with field work, often under unpleasant conditions. K. Wauthier was instrumental in wrestling the gamma counter into submission. P. Redman and C. Hambly conducted the isotopic analyses. K. Scott and K. Campbell provided the FoxBox. K.H.E. benefited from a Natural Sciences and Engineering Research Council (NSERC) Vanier Scholarship, Association of Canadian Universities for Northern Studies Garfield Weston Northern Studies Award and the Arctic Institute of North America Jennifer Robinson Scholarship. Research support came from Bird Studies Canada/Society of Canadian Ornithologists James Baillie Award, Animal Behavior Society Research Grant, American Ornithologists’ Union Research Grant, Frank Chapman Research Grant, the Waterbird Society Nisbet Grant and NSERC Discovery Grants to J.F.H. and W.G.A. Any use of trade names is for descriptive purposes only and does not imply endorsement by the US Government.Peer reviewedPublisher PD

Kepler Observations of the Three Pre-Launch Exoplanet Candidates: Discover of Two Eclipsing Binaries and a New Exoplanet

Three transiting exoplanet candidate stars were discovered in a ground-based photometric survey prior to the launch of NASA's Kepler mission. Kepler observations of them were obtained during Quarter 1 of the Kepler mission. All three stars are faint by radial velocity follow-up standards, so we have examined these candidates with regard to eliminating false positives and providing high confidence exoplanet selection. We present a first attempt to exclude false positives for this set of faint stars without high-resolution radial velocity analysis. This method of exoplanet confirmation will form a large part of the Kepler mission follow-up for Jupiter-sized exoplanet candidates orbiting faint stars. Using the Kepler light curves and pixel data, as well as medium-resolution reconnaissance spectroscopy and speckle imaging, we find that two of our candidates are binary stars. One consists of a late-F star with an early M companion, while the other is a K0 star plus a late M-dwarf/brown dwarf in a 19 day elliptical orbit. The third candidate (BOKS-1) is an r = 15 G8V star hosting a newly discovered exoplanet with a radius of 1.12 R_(Jupiter) in a 3.9 day orbit

Phleborheography: A Correlative Study with Venography

The Vascular Laboratory of Henry Ford Hospital has used the Cranley-Grass Phleborheograph (PRG) as the primary noninvasive method to determine the presence or absence of deep venous thrombosis (DVT) in the lower limbs since December 1977. In order to determine its proper role and clinical reliability, we compared the diagnostic accuracy of phleborheography with contrast venography. From December 1977 through December 1978, 483 cases (963 limbs) were successfully examined by PRG. Ofthese, 111 cases (216 limbs) also had contrast venography. The PRG was confirmed as normal in 151 out of 157 (6 false negatives). There were 53 abnormal PRCs, with 35 confirmed by venography and 18 false positives. Six PRCs were considered equivocal. Sensitivity on a per limb basis was .85. The overall specificity was .86, and when equivocal examinations were excluded, it was .89. Phleborheography is safe, reliable, widely applicable, and well-tolerated. However, skilled technicians and careful interpretation are essential to its success

Paying the pipers: mitigating the impact of anticoagulant rodenticides on predators and scavengers

Anticoagulant rodenticides, mainly second-generation forms, or SGARs, dominate the global market for rodent control. Introduced in the 1970s to counter genetic resistance in rodent populations to first-generation compounds such as warfarin, SGARs are extremely toxic and highly effective killers. However, their tendency to persist and accumulate in the body has led to the widespread contamination of terrestrial predators and scavengers. Commercial chemicals that are classified by regulators as persistent, bio-accumulative, and toxic (PBT) chemicals and that are widely used with potential environmental release, such as dichloro-diphenyl-trichloroethane (DDT) or polychlorinated biphenyls (PCBs), have been removed from commerce. However, despite consistently failing ecological risk assessments, SGARs remain in use because of the demand for effective rodent-control options and the lack of safe and humane alternatives. Although new risk-mitigation measures for rodenticides are now in effect in some countries, the contamination and poisoning of nontarget wildlife are expected to continue. Here, we suggest options to further attenuate this problem

Adverse outcome pathway and risks of anticoagulant rodenticides to predatory wildlife

Despite a long history of successful use, routine application of some anticoagulant rodenticides (ARs) may be at a crossroad due to new regulatory guidelines intended to mitigate risk. An adverse outcome pathway for ARs was developed to identify information gaps and end points to assess the effectiveness of regulations. This framework describes chemical properties of ARs, established macromolecular interactions by inhibition of vitamin K epoxide reductase, cellular responses including altered clotting factor processing and coagulopathy, organ level effects such as hemorrhage, organism responses with linkages to reduced fitness and mortality, and potential consequences to predator populations. Risk assessments have led to restrictions affecting use of some second-generation ARs (SGARs) in North America. While the European regulatory community highlighted significant or unacceptable risk of ARs to nontarget wildlife, use of SGARs in most EU member states remains authorized due to public health concerns and the absence of safe alternatives. For purposes of conservation and restoration of island habitats, SGARs remain a mainstay for eradication of invasive species. There are significant data gaps related to exposure pathways, comparative species sensitivity, consequences of sublethal effects, potential hazards of greater AR residues in genetically resistant prey, effects of low-level exposure to multiple rodenticides, and quantitative data on the magnitude of nontarget wildlife mortality