260 research outputs found
The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
The all sky surveys done by the Palomar Observatory Schmidt, the European
Southern Observatory Schmidt, and the United Kingdom Schmidt, the InfraRed
Astronomical Satellite and the 2 Micron All Sky Survey have proven to be
extremely useful tools for astronomy with value that lasts for decades. The
Wide-field Infrared Survey Explorer is mapping the whole sky following its
launch on 14 December 2009. WISE began surveying the sky on 14 Jan 2010 and
completed its first full coverage of the sky on July 17. The survey will
continue to cover the sky a second time until the cryogen is exhausted
(anticipated in November 2010). WISE is achieving 5 sigma point source
sensitivities better than 0.08, 0.11, 1 and 6 mJy in unconfused regions on the
ecliptic in bands centered at wavelengths of 3.4, 4.6, 12 and 22 microns.
Sensitivity improves toward the ecliptic poles due to denser coverage and lower
zodiacal background. The angular resolution is 6.1, 6.4, 6.5 and 12.0
arc-seconds at 3.4, 4.6, 12 and 22 microns, and the astrometric precision for
high SNR sources is better than 0.15 arc-seconds.Comment: 22 pages with 19 included figures. Updated to better match the
accepted version in the A
Integral Abutment Bridges under Thermal Loading: Field Monitoring and Analysis
Integral abutment bridges (IABs) have gained popularity throughout the United States due to their low construction and maintenance costs. Previous research on IABs has been heavily focused on substructure performance, leaving a need for better understanding of IAB superstructure behavior and interdependent effects. This report presents findings of a field monitoring program for two Illinois IABs (which supplements findings from a parametric study portion of the overall project that are summarized in a previous volume). The field monitoring program included collecting data about (i) global bridge movements; (ii) pile, deck, girder, and approach-slab strains; and (iii) rotations at different abutment interfaces. Field results have been compared to finite-element models of each bridge in order to provide further insight into IAB behavior. Field monitoring results corroborated that IAB longitudinal expansion and contraction is somewhat less than theoretical free expansion and contraction, and is influenced by bridge skew as well. Significant girder stresses were observed, particularly at the girder bottom flange, which should be considered in design. Pile strain values indicate there is likely some reserve pile-deformation capacity typically available.IDOT-R27-115Ope
Meiotic Transmission of Drosophila pseudoobscura Chromosomal Arrangements
Drosophila pseudoobscura harbors a rich gene arrangement polymorphism on the third chromosome generated by a series of overlapping paracentric inversions. The arrangements suppress recombination in heterokaryotypic individuals, which allows for the selective maintenance of coadapted gene complexes. Previous mapping experiments used to determine the degree to which recombination is suppressed in gene arrangement heterozygotes produced non-recombinant progeny in non-Mendelian ratios. The deviations from Mendelian expectations could be the result of viability differences between wild and mutant chromosomes, meiotic drive because of achiasmate pairing of homologues in heterokaryotypic females during meiosis, or a combination of both mechanisms. The possibility that the frequencies of the chromosomal arrangements in natural populations are affected by mechanisms other than adaptive selection led us to consider these hypotheses. We performed reciprocal crosses involving both heterozygous males and females to determine if the frequency of the non-recombinant progeny deviates significantly from Mendelian expectations and if the frequencies deviate between reciprocal crosses. We failed to observe non-Mendelian ratios in multiple crosses, and the frequency of the non-recombinant classes differed in only one of five pairs of reciprocal crosses despite sufficient power to detect these differences in all crosses. Our results indicate that deviations from Mendelian expectations in recombination experiments involving the D. pseudoobscura inversion system are most likely due to fitness differences of gene arrangement karyotypes in different environments
Physical Examination Variables Predict Response to Conservative Treatment of Nonchronic Plantar Fasciitis: Secondary Analysis of a Randomized, Placeboâ Controlled Footwear Study
BackgroundPlantar fasciitis is a common, disabling condition, and the prognosis of conservative treatment is difficult to predict.ObjectiveTo determine whether initial clinical findings could help predict patient response to conservative treatment that primarily consisted of supportive footwear and stretching.SettingPatients were recruited and seen at 2 outpatient podiatric clinics in the Chicago, Illinois, metropolitan area.PatientsSeventyâ seven patients with nonchronic plantar fasciitis were recruited. Patients were excluded if they had a heel injection in the previous 6 months or were currently using custom foot orthoses at the time of screening. Sixtyâ nine patients completed the final followâ up visit 3 months after receiving the footwear intervention.MethodsTreatment failure was considered a <50% reduction in heel pain at 3 month followâ up. Logistic regression models evaluated the possible association between more than 30 clinical and physical examination findings prospectively assessed at enrollment, and treatment response.ResultsInability to dorsiflex the ankle past â 5° (odds ratio [OR] 3.9, P = .024), nonsevere (â ¤7 on ordinal scale) firstâ step pain (OR 3.8, P = .021), and heel valgus in relaxed stance (OR 4.0, P = .014) each predicted treatment failure in multivariable analysis (receiver operating characteristic area under the curve = .769). Limited ankle dorsiflexion also correlated with greater heel pain severity at initial presentation (r = â 0.312, P = .006).ConclusionsPatients with severe ankle equinus were nearly 4 times more likely to experience a favorable response to treatment centered on home Achilles tendon stretching and supportive therapy. Thus, earlier use of more advanced therapies may be most appropriate in those presenting without severe ankle equinus or without severe first step pain. The findings from our study may not be clinically intuitive because patients with less severe equinus and less severe pain at presentation did worse with conservative care.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146867/1/pmrj436.pd
The Atacama Cosmology Telescope: Extragalactic Sources at 148 GHz in the 2008 Survey
We report on extragalactic sources detected in a 455 square-degree map of the
southern sky made with data at a frequency of 148 GHz from the Atacama
Cosmology Telescope 2008 observing season. We provide a catalog of 157 sources
with flux densities spanning two orders of magnitude: from 15 to 1500 mJy.
Comparison to other catalogs shows that 98% of the ACT detections correspond to
sources detected at lower radio frequencies. Three of the sources appear to be
associated with the brightest cluster galaxies of low redshift X-ray selected
galaxy clusters. Estimates of the radio to mm-wave spectral indices and
differential counts of the sources further bolster the hypothesis that they are
nearly all radio sources, and that their emission is not dominated by
re-emission from warm dust. In a bright (>50 mJy) 148 GHz-selected sample with
complete cross-identifications from the Australia Telescope 20 GHz survey, we
observe an average steepening of the spectra between 5, 20, and 148 GHz with
median spectral indices of , , and . When the
measured spectral indices are taken into account, the 148 GHz differential
source counts are consistent with previous measurements at 30 GHz in the
context of a source count model dominated by radio sources. Extrapolating with
an appropriately rescaled model for the radio source counts, the Poisson
contribution to the spatial power spectrum from synchrotron-dominated sources
with flux density less than 20 mJy is C^{\rm Sync} = (2.8 \pm 0.3) \times
10^{-6} \micro\kelvin^2.Comment: Accepted to Ap
The Atacama Cosmology Telescope: A Measurement of the Cosmic Microwave Background Power Spectrum at 148 and 218 GHz from the 2008 Southern Survey
We present measurements of the cosmic microwave background (CMB) power
spectrum made by the Atacama Cosmology Telescope at 148 GHz and 218 GHz, as
well as the cross-frequency spectrum between the two channels. Our results
clearly show the second through the seventh acoustic peaks in the CMB power
spectrum. The measurements of these higher-order peaks provide an additional
test of the {\Lambda}CDM cosmological model. At l > 3000, we detect power in
excess of the primary anisotropy spectrum of the CMB. At lower multipoles 500 <
l < 3000, we find evidence for gravitational lensing of the CMB in the power
spectrum at the 2.8{\sigma} level. We also detect a low level of Galactic dust
in our maps, which demonstrates that we can recover known faint, diffuse
signals.Comment: 19 pages, 13 figures. Submitted to ApJ. This paper is a companion to
Hajian et al. (2010) and Dunkley et al. (2010
JWST MIRI flight performance: The Medium-Resolution Spectrometer
The Medium-Resolution Spectrometer (MRS) provides one of the four operating
modes of the Mid-Infrared Instrument (MIRI) on board the James Webb Space
Telescope (JWST). The MRS is an integral field spectrometer, measuring the
spatial and spectral distributions of light across the 5-28 wavelength
range with a spectral resolving power between 3700-1300. We present the MRS's
optical, spectral, and spectro-photometric performance, as achieved in flight,
and we report on the effects that limit the instrument's ultimate sensitivity.
The MRS flight performance has been quantified using observations of stars,
planetary nebulae, and planets in our Solar System. The precision and accuracy
of this calibration was checked against celestial calibrators with well-known
flux levels and spectral features. We find that the MRS geometric calibration
has a distortion solution accuracy relative to the commanded position of 8 mas
at 5 and 23 mas at 28 . The wavelength calibration is accurate
to within 9 km/sec at 5 and 27 km/sec at 28 . The uncertainty in
the absolute spectro-photometric calibration accuracy was estimated at 5.6 +-
0.7 %. The MIRI calibration pipeline is able to suppress the amplitude of
spectral fringes to below 1.5 % for both extended and point sources across the
entire wavelength range. The MRS point spread function (PSF) is 60 % broader
than the diffraction limit along its long axis at 5 and is 15 % broader
at 28 . The MRS flight performance is found to be better than prelaunch
expectations. The MRS is one of the most subscribed observing modes of JWST and
is yielding many high-profile publications. It is currently humanity's most
powerful instrument for measuring the mid-infrared spectra of celestial sources
and is expected to continue as such for many years to come.Comment: 16 pages, 21 figure
The Atacama Cosmology Telescope: Data Characterization and Map Making
We present a description of the data reduction and mapmaking pipeline used
for the 2008 observing season of the Atacama Cosmology Telescope (ACT). The
data presented here at 148 GHz represent 12% of the 90 TB collected by ACT from
2007 to 2010. In 2008 we observed for 136 days, producing a total of 1423 hours
of data (11 TB for the 148 GHz band only), with a daily average of 10.5 hours
of observation. From these, 1085 hours were devoted to a 850 deg^2 stripe (11.2
hours by 9.1 deg) centered on a declination of -52.7 deg, while 175 hours were
devoted to a 280 deg^2 stripe (4.5 hours by 4.8 deg) centered at the celestial
equator. We discuss sources of statistical and systematic noise, calibration,
telescope pointing, and data selection. Out of 1260 survey hours and 1024
detectors per array, 816 hours and 593 effective detectors remain after data
selection for this frequency band, yielding a 38% survey efficiency. The total
sensitivity in 2008, determined from the noise level between 5 Hz and 20 Hz in
the time-ordered data stream (TOD), is 32 micro-Kelvin sqrt{s} in CMB units.
Atmospheric brightness fluctuations constitute the main contaminant in the data
and dominate the detector noise covariance at low frequencies in the TOD. The
maps were made by solving the least-squares problem using the Preconditioned
Conjugate Gradient method, incorporating the details of the detector and noise
correlations. Cross-correlation with WMAP sky maps, as well as analysis from
simulations, reveal that our maps are unbiased at multipoles ell > 300. This
paper accompanies the public release of the 148 GHz southern stripe maps from
2008. The techniques described here will be applied to future maps and data
releases.Comment: 20 pages, 18 figures, 6 tables, an ACT Collaboration pape
Pennsylvania Folklife Vol. 38, No. 4
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