12,076 research outputs found

    Literacy, Numeracy and Labour Market Outcomes in Canada

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    Most research on the contribution of human capital to economic growth and its role in the distribution of income uses indirect measures of human capital such as educational attainment and work experience. Such measures are arguably inputs into the production of human capital in the form of skills, competencies and knowledge. This study uses Canadian data from the international Adult Literacy Survey to analyse the role of directly observed skills -- specifically, prose, document and quantitative literacy -- on individual labour market earnings. The contributions of unobserved skills are taken into account using input measures (education and experience). We find that literacy skills have a large and statistically significant causal effect on earnings. As much as one-third of the return to education may be due to the combined effects of education on literacy and of literacy skills on earnings. In contrast, very little of the return to labour market experience is associated with the combined effects of experience on literacy and literacy skills on earnings.

    Narratives of the self in bilingual speakers: the neurophenomenal space

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    We tell one another stories of our lives. Sharing subjective experience is part of what it means to be an embodied, languaging being. In order to explore this aspect of our nature we need to relate our phenomenal experience to its neural bases as we talk. I describe a three-step procedure to do so as a person recounts a personal story. The first step characterizes their subjective experience. I describe two complementary ways to do so. The second step infers the attentional and attributional processes that compose that experience. I suppose that telling a personal story is a form of reliving it. The process of mental simulation involved recruits other attributional processes and is itself nested under one that sustains attention to the goal of telling the story. The third step identifies these processes with their possible neural bases expressed through the language network. I take the mapping from the phenomenal to the neural to be the neurophenomenal space and offer a visualization of it. I illustrate the procedure using the hypothetical example of a bilingual speaker who tells of a recent experience walking in a new city

    Infection frequently triggers thrombotic microangiopathy in patients with preexisting risk factors : a single-institution experience

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    Thrombotic microangiopathies are rare conditions characterized by microangiopathic hemolytic anemia, microthrombi, and multiorgan insult. The disorders, which include hemolytic uremic syndrome and thrombotic thrombocytopenic purpura, are often acute and life threatening. We report a retrospective analysis of 65 patients presenting to our institution from 1997 to 2008 with all forms of thrombotic microangiopathy. Therapeutic plasma exchange was a requirement for analysis and 65 patients were referred to our institution; 66% of patients were female and median age at presentation was 52 years. Bacterial infection was the most commonly identified etiologic factor and in the multivariate model was the only significant variable associated with survival outcome (odds ratio 5.1, 95% confidence interval, 1.2-21.7). As infection can be considered a common trigger event for thrombotic microangiopathy, patients with hepatobiliary sepsis may benefit from elective cholecystectomy. We conclude that bacterial infection frequently triggers TTP and other thrombotic microangiopathies in patients with preexisting risk factors and propose a model for the development of these syndromes

    Ageing and literacy skills: Evidence from Canada, Norway and the United States

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    We study the relationship between age and literacy skills in Canada, Norway and the U.S. &- countries that represent a wide range of literacy outcomes - using data from the 1994 and 2003 International Adult Literacy Surveys. In cross-sectional data there is a weak negative partial relationship between literacy skills and age. However, this relationship could reflect some combination of age and cohort effects. In order to identify age effects, we use the 1994 and 2003 surveys to create synthetic cohorts. Our analysis shows that the modest negative slope of the literacy-age profile in cross-sectional data arises from offsetting ageing and cohort effects. Individuals from a given birth cohort lose literacy skills after they leave school at a rate greater than indicated by cross-sectional estimates. At the same time, more recent birth cohorts have lower levels of literacy. These results suggest a pervasive tendency for literacy skills to decline over time and that these countries are doing a poorer job of educating successive generations. All three countries show similar patterns of skill loss with age, as well as declining literacy across successive cohorts. The countries differ, however, in the part of the skill distribution where falling skills are most evident. In Canada the cross-cohort declines are especially large at the top of the skill distribution. In Norway declining skills across cohorts are more prevalent at the bottom of the distribution. In the U.S. the decline in literacy skills over time is most pronounced in the middle of the distribution

    Constructing A Flexible Likelihood Function For Spectroscopic Inference

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    We present a modular, extensible likelihood framework for spectroscopic inference based on synthetic model spectra. The subtraction of an imperfect model from a continuously sampled spectrum introduces covariance between adjacent datapoints (pixels) into the residual spectrum. For the high signal-to-noise data with large spectral range that is commonly employed in stellar astrophysics, that covariant structure can lead to dramatically underestimated parameter uncertainties (and, in some cases, biases). We construct a likelihood function that accounts for the structure of the covariance matrix, utilizing the machinery of Gaussian process kernels. This framework specifically address the common problem of mismatches in model spectral line strengths (with respect to data) due to intrinsic model imperfections (e.g., in the atomic/molecular databases or opacity prescriptions) by developing a novel local covariance kernel formalism that identifies and self-consistently downweights pathological spectral line "outliers." By fitting many spectra in a hierarchical manner, these local kernels provide a mechanism to learn about and build data-driven corrections to synthetic spectral libraries. An open-source software implementation of this approach is available at http://iancze.github.io/Starfish, including a sophisticated probabilistic scheme for spectral interpolation when using model libraries that are sparsely sampled in the stellar parameters. We demonstrate some salient features of the framework by fitting the high resolution VV-band spectrum of WASP-14, an F5 dwarf with a transiting exoplanet, and the moderate resolution KK-band spectrum of Gliese 51, an M5 field dwarf.Comment: Accepted to ApJ. Incorporated referees' comments. New figures 1, 8, 10, 12, and 14. Supplemental website: http://iancze.github.io/Starfish

    Mechanical Properties of Red Maple Structural Lumber

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    Efficient utilization of hardwood structural lumber depends on developing better procedures of grading and property assignment. In this study, we evaluated the properties of red maple 2- by 4-in. (standard 38- by 89-mm) lumber tested in bending and in tension and compression parallel to the grain and compared the results to published values derived by ASTM D 245 clear wood procedures. The results indicate that significant increases in allowable properties could be obtained using procedures based on tests of full-size lumber. The results also demonstrate that the relationships between lumber strength in compression parallel to grain and bending strength and between tension parallel to grain and bending strength are similar to those for softwood species. Thus, procedures used to assign properties to mechanically graded softwood species should be applicable to red maple

    Durability of Structural Lumber Products at High Temperatures. Part I. 66°C at 75%RH and 82°C at 30%RH

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    Background. The effect of temperature on properties can be separated into reversible and permanent effects. The National Design Specification (NDS) provides factors (Ct) for reducing properties for reversible effects but provides little guidance on permanent effects.Objectives. The primary objective of this paper is to evaluate the effect of prolonged heating (permanent effect) on the flexural properties of solid-sawn and composite lumber products exposed at 66°C and 75% relative humidity (RH) and at 82°C and 30% RH. A second objective is to determine how to estimate total effects.Procedures. Solid-sawn lumber, laminated veneer lumber (LVL), and laminated strand lumber (LSL) were heated continuously for up to 6 years. After each exposure period, the lumber was conditioned to room temperature at the specified RH and then tested on edge in third-point bending. Some lumber was also tested hot at 66°C after 48 h of exposure and after 3 years of exposure.Results. After 3 years of continuous exposure at 66°C and 75% RH, solid-sawn Spruce-Pine-Fir (SPF) and Douglas-fir retained about 72% of their original modulus of rupture (MOR) and southern pine about 47%. For the first 2 to 3 years of exposure, changes in MOR of LVL were similar to that of solid-sawn SPF and Douglas-fir. After almost 6 years of exposure, SPF retained about 67% MOR and LVL 26% to 49%. The MOR of LSL was more sensitive to duration of exposure than was the MOR of either solid-sawn lumber or LVL, with a residual MOR of 47% after 28 months. After 21 months at 82°C and 30% RH, solid-sawn lumber retained 50% to 55% MOR, LVL 41%, and LSL 45%. For all products, modulus of elasticity was less sensitive to thermal degradation than was MOR.Conclusions. The effect of temperature on MOR of solid-sawn lumber is independent of grade. Composite lumber is more sensitive than solid-sawn to change in strength due to thermal degradation. The difference in MOR between species and product types may be less at low humidity levels than at high. The total effect of temperature on MOR can be estimated by adding the reversible plus the permanent effects. Available literature suggests that the wood used in attics of residential construction is not likely to experience significant accumulation of exposure at temperatures ≥66°C over the life of the structure

    Predicting The Effect of Moisture Content On The Flexural Properties of Douglas-Fir Dimension Lumber

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    Current procedures for adjusting estimates of the mechanical properties of lumber for changes in moisture content are based on trends in the observed means. The present study was initiated to develop analytical procedures for adjusting estimates of the flexural properties of 2-inch-thick Douglas-fir dimension lumber that would be applicable to all levels of the flexural properties. Equations are derived for adjusting modulus of rupture (MOR), modulus of elasticity (MOE), moment capacity (RS = MOR x section modulus), and flexural stiffness (EI = MOEX moment of inertia) for changes in moisture content. The best of these equations are found to be significantly more accurate than current procedures for adjusting estimates of strength properties such as MOR and RS. Because MOE and EI are less affected by changes in moisture content, most of the equations work well for these properties
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