610 research outputs found

    "The Measurement of Chronic and Transitory Poverty: with Application to the United States"

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    This paper proposes a method of measuring chronic and transitory poverty based on any additively-decomposable index of aggregate poverty. Chronic poverty and transitory poverty in the United States are measured using data from the Panel Study of Income Dynamics (1987 interviewing year). In an attempt to identify the most impoverished subpopulations, poverty indices are decomposed according to race, type of household and educational qualifications of the head of the household.

    The Effect of Geographic Mobility on Male Labour-Force Particpants in the United States

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    We use both fixed-effects and random-effects regression models to measure the effect of geographic mobility on earnings of labor-force participants in the United States. The results support the human-capital hypothesis: six years after moving, real earnings of male labor-force participants are about 20 percent higher than they would have been had the move not occurred. Men younger than 40, and men with family-unit incomes no more than five times the poverty line, experience even larger benefits from moving. The geographic mobility that is characteristic of the United States’ flexible labor market, in general, is beneficial to the movers

    Measurement Error In Cross-Sectional and Longitudinal Labor Market Surveys: Results From Two Validation Studies

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    This paper reports evidence on the error properties of survey reports of labor market variables such as earnings and work hours. Our primary data source is the PSID Validation Study, a two-wave panel survey of a sample of workers employed by a large firm which also allowed us access to its very detailed records of its workers earnings. etc. The second data source uses individuals' 1977 and 1978 (March Current Population Survey) reports of earnings, matched to Social Security earnings records. In both data sets, individuals: reports of earnings are fairly accurately reported, and the errors are negatively related to true earnings. The latter property reduces the bias due to measurement error when earnings are used as an independent variable, but (unlike the classical-error case) leads to some bias when earnings are the dependent variable. Measurement-error-induced biases when change in earnings is the variable of interest are larger, but not dramatically so. Various measures of hourly earnings were much less reliable than annual earnings. Retrospective reports of unemployment showed considerable under-reporting, even of long spells.

    Quantitative PCR assays for detection of five Alaskan fish species: Lota lota, Salvelinus alpinus, Salvelinus malma, Thymallus arcticus, and Cottus cognatus from environmental DNA

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    The North Slope of Alaska contains arctic fish populations that are important for subsistence of local human populations, and under threat from natural resource extraction and climate change. We designed and evaluated four quantitative PCR assays for detection of environmental DNA from five Alaskan fish species present on the North Slope of Alaska: burbot (Lota lota), arctic char (Salvelinus alpinus), Dolly Varden (Salvelinus malma), arctic grayling (Thymallus arcticus), and slimy sculpin (Cottus cognatus). All assays were designed and tested for species specificity and sensitivity, and all assays detected target species from filtered water samples collected from the field. These assays will enable efficient and economical detection of the above species from lakes and rivers. This in turn will provide managers with improved knowledge of current distributions and future range shifts associated with climate and development threats, enabling more timely management

    (±)-9-exo-Amino-5,6,7,8-tetrahydro-5,8-methano-9H-benzocyclohepten-8-ol Hydrochloride

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    This is the published version, also available here: http://www.dx.doi.org/10.1107/S0567740878004458

    Stress Preconditioning of Spreading Depression in the Locust CNS

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    Cortical spreading depression (CSD) is closely associated with important pathologies including stroke, seizures and migraine. The mechanisms underlying SD in its various forms are still incompletely understood. Here we describe SD-like events in an invertebrate model, the ventilatory central pattern generator (CPG) of locusts. Using K+ -sensitive microelectrodes, we measured extracellular K+ concentration ([K+]o) in the metathoracic neuropile of the CPG while monitoring CPG output electromyographically from muscle 161 in the second abdominal segment to investigate the role K+ in failure of neural circuit operation induced by various stressors. Failure of ventilation in response to different stressors (hyperthermia, anoxia, ATP depletion, Na+/K+ ATPase impairment, K+ injection) was associated with a disturbance of CNS ion homeostasis that shares the characteristics of CSD and SD-like events in vertebrates. Hyperthermic failure was preconditioned by prior heat shock (3 h, 45°C) and induced-thermotolerance was associated with an increase in the rate of clearance of extracellular K+ that was not linked to changes in ATP levels or total Na+/K+ ATPase activity. Our findings suggest that SD-like events in locusts are adaptive to terminate neural network operation and conserve energy during stress and that they can be preconditioned by experience. We propose that they share mechanisms with CSD in mammals suggesting a common evolutionary origin

    The enthalpies of combustion and formation of [2.2]-paracyclophane and triptycene

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    The enthalpies of combustion, ΔHoc, for crystalline [2.2]-paracyclophane (C16H16) and triptycene (C20H14) have been measured by oxygen combustion calorimetry. The derived standard enthalpies of formation at 298.15 K in the crystalline state are (34.59±0.19) and (51.87±0.20) kcalth mol-1. The strain present in these molecular systems is discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33825/1/0000082.pd

    Quantitative PCR Assays for Detection of Five Arctic Fish Species: \u3ci\u3eLota lota\u3c/i\u3e, \u3ci\u3eCottus cognatus\u3c/i\u3e, \u3ci\u3eSalvelinus alpinus\u3c/i\u3e, \u3ci\u3eSalvelinus malma\u3c/i\u3e, and \u3ci\u3eThymallus arcticus\u3c/i\u3e from Environmental DNA

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    The North Slope of Alaska contains arctic fish populations that are important for subsistence of local human populations, and are under threat from natural resource extraction and climate change. We designed and evaluated four quantitative PCR assays for the detection of environmental DNA from five Alaskan fish species present on the North Slope of Alaska: burbot (Lota lota), arctic char (Salvelinus alpinus), Dolly Varden (Salvelinus malma), arctic grayling (Thymallus arcticus), and slimy sculpin (Cottus cognatus). All assays were designed and tested for species specificity and sensitivity, and all assays detected target species from filtered water samples collected from the field. These assays will enable efficient and economical detection and monitoring of these species in lakes and rivers. This in turn will provide managers with improved knowledge of current distributions and future range shifts associated with climate and development threats, enabling more timely management

    The Southern Galactic Plane Survey: The Test Region

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    The Southern Galactic Plane Survey (SGPS) is a project to image the HI line emission and 1.4 GHz continuum in the fourth quadrant of the Milky Way at high resolution using the Australia Telescope Compact Array (ATCA) and the Parkes Radio Telescope. In this paper we describe the survey details and goals, present lambda 21-cm continuum data, and discuss HI absorption and emission characteristics of the SGPS Test Region (325.5 deg < l < 333.5 deg; -0.5 deg < b < +3.5 deg). We explore the effects of massive stars on the interstellar medium (ISM) through a study of HI shells and the HI environments of HII regions and supernova remnants. We find an HI shell surrounding the HII region RCW 94 which indicates that the region is embedded in a molecular cloud. We give lower limits for the kinematic distances to SNRs G327.4+0.4 and G330.2+1.0 of 4.3 kpc and 4.9 kpc, respectively. We find evidence of interaction with the surrounding HI for both of these remnants. We also present images of a possible new SNR G328.6-0.0. Additionally, we have discovered two small HI shells with no counterparts in continuum emission.Comment: 17 pages, 7 embedded EPS figures, 10 low-res jpeg figures, uses emulateapj5.sty. Accepted for publication in the Astrophysical Journal. Version with all full resolution figures embedded is available at http://www.astro.umn.edu/~naomi/sgps/papers/SGPS.ps.g

    Long-term correction of ornithine transcarbamylase deficiency by WPRE-mediated overexpression using a helper-dependent adenovirus

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    The urea cycle disorders (UCDs) are important models for developing gene replacement therapy for liver diseases. Long-term correction of the most common UCD, ornithine transcarbamylase (OTC) deficiency, has yet to be achieved in clinical or preclinical settings. The single human clinical trial using early-generation adenovirus (Ad) failed to show any biochemical correction. In adult OTC-deficient mice, an E1/E2-deleted Ad vector expressing the mouse OTC gene, but not the human, was only transiently therapeutic. By using post-transcriptional overexpression in the context of the less immunogenic helper-dependent adenoviral vector, we achieved metabolic correction of adult OTC-deficient mice for \u3e6 months. Demonstrating this result were normalized orotic aciduria, normal hepatic enzyme activity, and elevated OTC RNA and protein levels in the absence of chronic hepatotoxicity. Overexpressing the human protein may have overcome two potential mechanisms accounting for poor cross-species complementation: a kinetic block at the level of mitochondrial import or a dominant negative effect by the mutant polypeptide. These data represent an important approach for treating human inborn errors of hepatocyte metabolism like the UCDs that require high-level transduction and gene expression for clinical correction
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