5,796 research outputs found

    Reading sentences with a late closure ambiguity: does semantic information help?

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    Stowe (1989) reported that semantic information eliminates garden paths in sentences with the direct-object vs. subject ambiguity, such as Even before the police stopped the driver was very frightened. Three experiments are presented which addressed some methodological problems in Stowe's study. Experiment 1, using a word-by-word, self-paced reading task with grammaticality judgements, manipulated animacy of the first subject noun while controlling for the plausibility of the transitive action. The results suggest that initial sentence analysis is not guided by animacy. Experiment 2 and 3, using the self-paced task with grammaticality judgements and eye-tracking, varied the plausibility of the direct-object nouns to test revision effects. Plausibility was found to facilitate revision without fully eliminating garden paths, in line with various revision models. The findings support the view of a sentence processing system relying heavily on syntactic information, with semantic information playing a weaker role both in initial analysis and during revision, thus supporting serial, syntax-first models and ranked-parallel models relying on structural criteria

    A foundation for provitamin A biofortification of maize: genome-wide association and genomic prediction models of carotenoid levels.

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    Efforts are underway for development of crops with improved levels of provitamin A carotenoids to help combat dietary vitamin A deficiency. As a global staple crop with considerable variation in kernel carotenoid composition, maize (Zea mays L.) could have a widespread impact. We performed a genome-wide association study (GWAS) of quantified seed carotenoids across a panel of maize inbreds ranging from light yellow to dark orange in grain color to identify some of the key genes controlling maize grain carotenoid composition. Significant associations at the genome-wide level were detected within the coding regions of zep1 and lut1, carotenoid biosynthetic genes not previously shown to impact grain carotenoid composition in association studies, as well as within previously associated lcyE and crtRB1 genes. We leveraged existing biochemical and genomic information to identify 58 a priori candidate genes relevant to the biosynthesis and retention of carotenoids in maize to test in a pathway-level analysis. This revealed dxs2 and lut5, genes not previously associated with kernel carotenoids. In genomic prediction models, use of markers that targeted a small set of quantitative trait loci associated with carotenoid levels in prior linkage studies were as effective as genome-wide markers for predicting carotenoid traits. Based on GWAS, pathway-level analysis, and genomic prediction studies, we outline a flexible strategy involving use of a small number of genes that can be selected for rapid conversion of elite white grain germplasm, with minimal amounts of carotenoids, to orange grain versions containing high levels of provitamin A

    Long-term follow-up, quality of life, and survival of patients with Lambert-Eaton myasthenic syndrome

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    ObjectiveTo study survival and to characterize long-term functional impairments and health-related quality of life (HRQOL) of patients with Lambert-Eaton myasthenic syndrome (LEMS).MethodsIn this observational study, survival of patients with LEMS, separately for nontumor (NT) and small cell lung cancer (SCLC), was compared to that of the Dutch general population and patients with SCLC. Disease course in patients with LEMS was recorded retrospectively. Several scales for functional impairments and health-related quality of life were assessed.ResultsWe included 150 patients with LEMS. Survival was similar to that of the general population in 65 patients with NT-LEMS. Tumor survival was significantly longer in 81 patients with SCLC-LEMS compared to patients with non-LEMS SCLC (overall median survival 17 vs 7.0 months, p <0.0001). At diagnosis, 39 (62%) of 63 patients with complete follow-up data were independent for activities of daily living, improving to 85% at the 1-year follow-up. The physical HRQOL composite score (55.9) was significantly lower than in the general population (76.3, p <0.0001) and comparable to that of patients with myasthenia gravis (60.5). The mental HRQOL composite score was 71.8 in patients with LEMS, comparable to that of the general population (77.9, p = 0.19) and patients with myasthenia gravis (70.3).ConclusionsThis study shows that patients with NT-LEMS have normal survival. Patients with SCLC-LEMS have an improved tumor survival, even after correction for tumor stage. A majority of patients with LEMS report a stable disease course and remain or become independent for self-care after treatment

    First Measurement of the Tensor Structure Function b1b_1 of the Deuteron

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    The \Hermes experiment has investigated the tensor spin structure of the deuteron using the 27.6 GeV/c positron beam of \Hera. The use of a tensor polarized deuteron gas target with only a negligible residual vector polarization enabled the first measurement of the tensor asymmetry \At and the tensor structure function \bd for average values of the Bj{\o}rken variable 0.01<0.450.01<0.45 and of the squared four-momentum transfer 0.5GeV2<5GeV20.5 {\rm GeV^2} <5 {\rm GeV^2}. The quantities \At and \bd are found to be non-zero. The rise of \bd for decreasing values of xx can be interpreted to originate from the same mechanism that leads to nuclear shadowing in unpolarized scattering

    Flavor decomposition of the sea quark helicity distributions in the nucleon from semi-inclusive deep-inelastic scattering

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    Double-spin asymmetries of semi-inclusive cross sections for the production of identified pions and kaons have been measured in deep-inelastic scattering of polarized positrons on a polarized deuterium target. Five helicity distributions including those for three sea quark flavors were extracted from these data together with re-analyzed previous data for identified pions from a hydrogen target. These distributions are consistent with zero for all three sea flavors. A recently predicted flavor asymmetry in the polarization of the light quark sea appears to be disfavored by the data.Comment: 5 pages, 3 figure

    Nuclear Polarization of Molecular Hydrogen Recombined on a Non-metallic Surface

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    The nuclear polarization of H2\mathrm{H}_2 molecules formed by recombination of nuclear polarized H atoms on the surface of a storage cell initially coated with a silicon-based polymer has been measured by using the longitudinal double-spin asymmetry in deep-inelastic positron-proton scattering. The molecules are found to have a substantial nuclear polarization, which is evidence that initially polarized atoms retain their nuclear polarization when absorbed on this type of surfac

    Quark helicity distributions in the nucleon for up, down, and strange quarks from semi--inclusive deep--inelastic scattering

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    Polarized deep--inelastic scattering data on longitudinally polarized hydrogen and deuterium targets have been used to determine double spin asymmetries of cross sections. Inclusive and semi--inclusive asymmetries for the production of positive and negative pions from hydrogen were obtained in a re--analysis of previously published data. Inclusive and semi--inclusive asymmetries for the production of negative and positive pions and kaons were measured on a polarized deuterium target. The separate helicity densities for the up and down quarks and the anti--up, anti--down, and strange sea quarks were computed from these asymmetries in a ``leading order'' QCD analysis. The polarization of the up--quark is positive and that of the down--quark is negative. All extracted sea quark polarizations are consistent with zero, and the light quark sea helicity densities are flavor symmetric within the experimental uncertainties. First and second moments of the extracted quark helicity densities in the measured range are consistent with fits of inclusive data
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