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631.
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633.
Background
Recently several studies have shown that people use contextual information to make predictions about the rest of the sentence or story as the text unfolds. Using event related potentials (ERPs) we tested whether these on-line predictions are based on a message-level representation of the discourse or on simple automatic activation by individual words. Subjects heard short stories that were highly constraining for one specific noun, or stories that were not specifically predictive but contained the same prime words as the predictive stories. To test whether listeners make specific predictions critical nouns were preceded by an adjective that was inflected according to, or in contrast with, the gender of the expected noun. 相似文献634.
Laurence Barker 《Journal of Algebra》2008,319(9):3810-3853
Rhetorical biset functors can be defined for any family of finite groups that is closed under subquotients up to isomorphism. The rhetorical p-biset functors almost coincide with the rational p-biset functors. We show that, over a field with characteristic zero, the rhetorical biset functors are semisimple and, furthermore, they admit a character theory involving primitive characters of automorphism groups of cyclic groups. 相似文献
635.
A. Cappelli R. Tuffi K. Schwertassek K. Czapla J. Plail E. Freedman H. Nechamkin R. Gerber K. Lathrop H. Rath O. Mecheels J. W. Groß E. v. Roll K. Heidler S. G. Barker B. A. Ryberg W. I. Tepnin P. M. Heertjes H. Anton F. Riecke W. Sserdjukow N. A. Juschkow 《Analytical and bioanalytical chemistry》1944,127(1):155-156
636.
Stability of Viscous Shocks in Isentropic Gas Dynamics 总被引:1,自引:0,他引:1
Blake Barker Jeffrey Humpherys Keith Rudd Kevin Zumbrun 《Communications in Mathematical Physics》2008,281(1):231-249
In this paper, we examine the stability problem for viscous shock solutions of the isentropic compressible Navier–Stokes equations,
or p-system with real viscosity. We first revisit the work of Matsumura and Nishihara, extending the known parameter regime for
which small-amplitude viscous shocks are provably spectrally stable by an optimized version of their original argument. Next,
using a novel spectral energy estimate, we show that there are no purely real unstable eigenvalues for any shock strength.
By related estimates, we show that unstable eigenvalues are confined to a bounded region independent of shock strength. Then
through an extensive numerical Evans function study, we show that there are no unstable spectra in the entire right-half plane,
thus demonstrating numerically that large-amplitude shocks are spectrally stable up to Mach number M ≈ 3000 for 1 ≤ γ ≤ 3. This strongly suggests that shocks are stable independent of amplitude and the adiabatic constant γ.
We complete our study by showing that finite-difference simulations of perturbed large-amplitude shocks converge to a translate
of the original shock wave, as expected.
This work was supported in part by the National Science Foundation award numbers DMS-0607721 and DMS-0300487. 相似文献
637.
Cercignani M Barker GJ 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2008,191(2):171-183
Quantitative models of magnetization transfer (MT) allow the estimation of physical properties of tissue which are thought to reflect myelination, and are therefore likely to be useful for clinical application. Although a model describing a two-pool system under continuous wave-saturation has been available for two decades, generalizing such a model to pulsed MT, and therefore to in vivo applications, is not straightforward, and only recently have a range of equations predicting the outcome of pulsed MT experiments been proposed. These solutions of the 2-pool model are based on differing assumptions and involve differing degrees of complexity, so their individual advantages and limitations are not always obvious. This paper is concerned with the comparison of three differing signal equations. After reviewing the theory behind each of them, their accuracy and precision is investigated using numerical simulations under variable experimental conditions such as degree of T1-weighting of the acquisition sequence and SNR, and the consistency of numerical results is tested using in vivo data. We show that while in conditions of minimal T1-weighting, high SNR, and large duty cycle the solutions of the three equations are consistent, they have a different tolerance to deviations from the basic assumptions behind their development, which should be taken into account when designing a quantitative MT protocol. 相似文献
638.
S M Leary G J Parker V L Stevenson G J Barker D H Miller A J Thompson 《Magnetic resonance imaging》1999,17(5):773-776
A sensitive magnetic resonance imaging (MRI) method to measure spinal cord cross-sectional area with the potential to monitor disease progression has recently been developed. As changes in cord area due to disease are usually small, assessment of the reliability of the methodology is essential in serial studies of spinal cord atrophy. The aim of this study was to institute and evaluate a protocol of quality assurance to determine long-term reproducibility of serial studies. Serial MRI of the spinal cord was carried out in five healthy volunteer controls over 1 year. Cross-sectional spinal cord areas were measured in a total of 46 scans. The mean coefficient of variation of all subjects over one year was 1.35%. The intra-observer coefficient of variation for same scan analysis was 0.63%. This study has confirmed high reliability of our serial data over one year and the on-going quality assurance protocol enables continuing evaluation of the reproducibility of results in serial studies. Quality assurance is an essential and practical component of all serial MRI studies, without which the clinical implications of change cannot be reliably evaluated. 相似文献
639.
Chun‐Lin Deng Jeremy P. Bard Jessica A. Lohrman Joshua E. Barker Lev N. Zakharov Darren W. Johnson Michael M. Haley 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(12):3974-3978
We describe two novel hybrid receptors combining a phosphorus‐/nitrogen‐containing (PN) phosphonamidate heterocycle with urea recognition units in an arylethynyl backbone. Structural, spectroscopic and computational studies reveal that the origin of superior binding for hydrogen sulfate (HSO4?) anion is correlated with the formation of strong hetero‐complementary hydrogen bonds with the phosphonamidate motif. We further demonstrate that the hybrid host system is capable of capturing/transporting the HSO4? anion from an aqueous, biphasic system. 相似文献
640.