6,646 research outputs found
âHardyâs Two Voices: âThe Oxenâ and its Contexts'
This essay surveys a variety of important contexts for considering Hardy's âThe Oxenâ: biographical, historical, literary-historical, religious, and personal, among them. It will seek to open up possibilities of reading the poem that extend beyond what can seem its de facto status as a (self-evident) exemplification of Hardy's attitudes on matters of religion. Critics sometimes give the impression that this is a poem about which there is little more to be said, but these pieces seek to counter this by close examination of its ways of saying. The companion essay (in a following issue) will offer a metrical reading of âThe Oxen,â seeking to show that a close study of the expressive dynamics of metre in this poem allow one to examine how extensive is the poem's meaning, and how characteristically it is shaped by an internal drama of voice and intonation
"The Exileâs Harpâ: Tennysonâs Lost World of Music
From the earliest reviews, the trope of music has shaped the image of Tennyson for critics and readers. Tennyson's talent is one that joins voice and ear:\ud
Nature [âŠ] has taught Mr. Tennyson to sing as a poet should sing, â she has taught him to throw his whole soul into his harmonies.\ud
He has a fine ear for melody and harmony too â and rare and rich glimpses of imagination. He has â genius
Image analysis of the AXAF VETA-I x ray mirror
Initial core scan data of the VETA-I x-ray mirror proved disappointing, showing considerable unpredicted image structure and poor measured FWHM. 2-D core scans were performed, providing important insight into the nature of the distortion. Image deconvolutions using a ray traced model PSF was performed successfully to reinforce our conclusion regarding the origin of the astigmatism. A mechanical correction was made to the optical structure, and the mirror was tested successfully (FWHM 0.22 arcsec) as a result
Supernova Remnant Kes 17: Efficient Cosmic Ray Accelerator inside a Molecular Cloud
Supernova remnant Kes 17 (SNR G304.6+0.1) is one of a few but growing number
of remnants detected across the electromagnetic spectrum. In this paper, we
analyze recent radio, X-ray, and gamma-ray observations of this object,
determining that efficient cosmic ray acceleration is required to explain its
broadband non-thermal spectrum. These observations also suggest that Kes 17 is
expanding inside a molecular cloud, though our determination of its age depends
on whether thermal conduction or clump evaporation is primarily responsible for
its center-filled thermal X-ray morphology. Evidence for efficient cosmic ray
acceleration in Kes 17 supports recent theoretical work that the strong
magnetic field, turbulence, and clumpy nature of molecular clouds enhances
cosmic ray production in supernova remnants. While additional observations are
needed to confirm this interpretation, further study of Kes 17 is important for
understanding how cosmic rays are accelerated in supernova remnants.Comment: 13 pages, 6 figures, 4 table
Preconditioning and triggering of offshore slope failures and turbidity currents revealed by most detailed monitoring yet at a fjord-head delta
Rivers and turbidity currents are the two most important sediment transport processes by volume on Earth. Various hypotheses have been proposed for triggering of turbidity currents offshore from river mouths, including direct plunging of river discharge, delta mouth bar flushing or slope failure caused by low tides and gas expansion, earthquakes and rapid sedimentation. During 2011, 106 turbidity currents were monitored at Squamish Delta, British Columbia. This enables statistical analysis of timing, frequency and triggers. The largest peaks in river discharge did not create hyperpycnal flows. Instead, delayed delta-lip failures occurred 8â11 h after flood peaks, due to cumulative delta top sedimentation and tidally-induced pore pressure changes. Elevated river discharge is thus a significant control on the timing and rate of turbidity currents but not directly due to plunging river water. Elevated river discharge and focusing of river discharge at low tides cause increased sediment transport across the delta-lip, which is the most significant of all controls on flow timing in this setting
Precision of the calibration of the AXAF engineering test article (VETA) mirrors
Measurements of the VETA encircled energies have been performed at 5 energies within 16 radii ranging from 0.05 to 200 arcseconds. We report here on the analysis of the accuracy of those measurements. A common 'error tree' structure applies, and we present representative numbers for the larger terms. At 0.277, 1.5, and 2.07 keV, and for radii of 3 arcsec and larger, our measurements have estimated 1 sigma errors of 0.6 to 1.5 percent. Effects of measurement statistics and of the VETA test mount limit the accuracy at smaller angles, and modulation by the counter window support structure together with the imperfect position repeatability limit the accuracy for the 0.93 and 2.3 keV energies. We expect to mitigate these limitations when calibrating the complete AXAF flight mirror assembly
0103-72.6: A New Oxygen-Rich Supernova Remnant in the Small Magellanic Cloud
010372.6, the second brightest X-ray supernova remnant (SNR) in the Small
Magellanic Cloud (SMC), has been observed with the {\it Chandra X-Ray
Observatory}. Our {\it Chandra} observation unambiguously resolves the X-ray
emission into a nearly complete, remarkably circular shell surrounding bright
clumpy emission in the center of the remnant. The observed X-ray spectrum for
the central region is evidently dominated by emission from reverse shock-heated
metal-rich ejecta. Elemental abundances in this ejecta material are
particularly enhanced in oxygen and neon, while less prominent in the heavier
elements Si, S, and Fe. We thus propose that 010372.6 is a new
``oxygen-rich'' SNR, making it only the second member of the class in the SMC.
The outer shell is the limb-brightened, soft X-ray emission from the swept-up
SMC interstellar medium. The presence of O-rich ejecta and the SNR's location
within an H{\small II} region attest to a massive star core-collapse origin for
010372.6. The elemental abundance ratios derived from the ejecta suggest an
18 M progenitor star.Comment: 6 pages (ApJ emulator format), including 5 figures and 2 tables. For
high quality Figs.1,2, & 3, contact [email protected]. Accepted by the ApJ
Letter
Equality of bond percolation critical exponents for pairs of dual lattices
For a certain class of two-dimensional lattices, lattice-dual pairs are shown
to have the same bond percolation critical exponents. A computational proof is
given for the martini lattice and its dual to illustrate the method. The result
is generalized to a class of lattices that allows the equality of bond
percolation critical exponents for lattice-dual pairs to be concluded without
performing the computations. The proof uses the substitution method, which
involves stochastic ordering of probability measures on partially ordered sets.
As a consequence, there is an infinite collection of infinite sets of
two-dimensional lattices, such that all lattices in a set have the same
critical exponents.Comment: 10 pages, 7 figure
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Within- and Between-Child Variation in Repeated Urinary Pesticide Metabolite Measurements over a 1-Year Period
Background: Children are exposed to pesticides from many sources and routes, including dietary and incidental ingestion, dermal absorption, and inhalation. Linking health outcomes to these exposures using urinary metabolites requires understanding temporal variability within subjects to avoid exposure misclassification. Objectives: We characterized the within- and between-child variability of urinary organophosphorus and pyrethroid metabolites in 23 participants of the Childrenâs Pesticide Exposure StudyâWashington over 1 year and examined the ability of one to four spot urine samples to categorize mean exposures. Methods: Each child provided urine samples twice daily over 7- to 16-day sessions in four seasons in 2003 and 2004. Samples were analyzed for five pyrethroid and five organophosphorus (OP) metabolites. After adjusting for specific gravity, we used a customized maximum likelihood estimation linear mixed-effects model that accounted for values below the limit of detection to calculate intraclass correlation coefficients (ICC) and conducted surrogate category analyses. Results: Within-child variability was 2â11 times greater than between-child variability. When restricted to samples collected during a single season, ICCs were higher in the fall, winter, and spring than in summer for OPs, and higher in summer and winter for pyrethroids, indicating an increase in between-person variability relative to within-person variability during these seasons. Surrogate category analyses demonstrated that a single spot urine sample did not categorize metabolite concentrations well, and that four or more samples would be needed to categorize children into quartiles consistently. Conclusions: Urinary biomarkers of these short half-life pesticides exhibited substantial within-person variability in children observed over four seasons. Researchers investigating pesticides and health outcomes in children may need repeated biomarker measurements to derive accurate estimates of exposure and relative risks. Citation: Attfield KR, Hughes MD, Spengler JD, Lu C. 2014. Within- and between-child variation in repeated urinary pesticide metabolite measurements over a 1-year period. Environ Health Perspect 122:201â206; http://dx.doi.org/10.1289/ehp.130673
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