826 research outputs found
ARCADE: Absolute Radiometer for Cosmology, Astrophysics, and Diffuse Emission
The Absolute Radiometer for Cosmology, Astrophysics, and Diffuse Emission
(ARCADE) is a balloon-borne instrument designed to measure the temperature of
the cosmic microwave background at centimeter wavelengths. ARCADE searches for
deviations from a blackbody spectrum resulting from energy releases in the
early universe. Long-wavelength distortions in the CMB spectrum are expected in
all viable cosmological models. Detecting these distortions or showing that
they do not exist is an important step for understanding the early universe. We
describe the ARCADE instrument design, current status, and future plans.Comment: 12 pages, 6 figures. Proceedings of the Fundamental Physics With CMB
workshop, UC Irvine, March 23-25, 2006, to be published in New Astronomy
Review
Comparison of the COBE FIRAS and DIRBE Calibrations
We compare the independent FIRAS and DIRBE observations from the COBE in the
wavelength range 100-300 microns. This cross calibration provides checks of
both data sets. The results show that the data sets are consistent within the
estimated gain and offset uncertainties of the two instruments. They show the
possibility of improving the gain and offset determination of DIRBE at 140 and
240 microns.Comment: Accepted for publication in the Astrophysical Journal 11 pages, plus
3 figures in separate postscript files. Figure 3 has three part
A Hydrodynamical Approach to CMB mu-distortions
Spectral distortion of the cosmic microwave background provides a unique
opportunity to probe primordial perturbations on very small scales by
performing large-scale measurements. We discuss in a systematic and pedagogic
way all the relevant physical phenomena involved in the production and
evolution of the mu-type spectral distortion. Our main results agree with
previous estimates (in particular we show that a recently found factor of 3/4
arises from relativistic corrections to the wave energy). We also discuss
several subleading corrections such as adiabatic cooling and the effects of
bulk viscosity, baryon loading and photon heat conduction. Finally we calculate
the transfer function for mu-distortions between the end of the mu-era and now.Comment: 45 page
Infant mental health home visiting therapists- fidelity to the Michigan IMH- HV model in community practice settings
Implementation research suggests that fidelity to a therapeutic model is important for enhancing outcomes, yet can be difficult to achieve in community practice settings. Furthermore, few published studies have reported on characteristics of treatment fidelity. The present study examined fidelity to the Infant Mental Health Home Visiting (IMH- HV) model among 51 therapists with a range of experience practicing in community settings across the state of Michigan. IMH therapists completed fidelity checklists after every session with participating families to track use of 15 treatment strategies central to the IMH- HV model across the 12- month study period. Results indicated that the most commonly endorsed components utilized in home visits were developmental guidance and infant- parent psychotherapy, followed by the provision of emotional support. Use of IMH- HV components did not vary over time for the entire sample; however, patterns of strategies used showed somewhat more variability among more experienced therapists and when serving higher risk families. Findings demonstrate that IMH- HV therapists report a range of adherence to the model in community settings, with greatest fidelity to several model core components. Ongoing training in the flexible use of all core strategies may further enhance fidelity and contribute to positive outcomes for caregivers and their children receiving IMH- HV services.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154900/1/imhj21839.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154900/2/imhj21839_am.pd
The Spectrum of the CMB Anisotropy from the Combined COBE FIRAS and DMR Observations
We analyze the Cosmic Microwave Background (CMB) anisotropy data from the
independent COBE FIRAS and DMR observations. We extract the frequency spectrum
of the FIRAS signal that has the spatial distribution seen by DMR and show that
it is consistent with CMB temperature fluctuations in the radiation well into
the Wien region of the spectrum. Conversely, we form a map of the Planckian
component of the sky temperature from FIRAS and show that it correlates with
the DMR anisotropy map. The rms fluctuations at angular scales of 7 degrees are
48 \pm 14 uK for the FIRAS data compared with 35 \pm 2 uK for the DMR data and
31 \pm 6 uK for the correlated combination (1 sigma uncertainties). The
consistency of these data, from very different instruments with very different
observing strategies, provide compelling support for the interpretation that
the signal seen by DMR is, in fact, temperature anisotropy of cosmological
origin. The data also limit rms fluctuations in the Compton y parameter,
observable via the Sunyaev- Zel'dovich effect, to Delta_y < 3 x 10^{-6} (95%
CL) on 7 degree angular scales.Comment: 15 pages, Latex (AASv4 macro) including 3 Postscript figures, to
appear in ApJ, vol. 486, Sept 10, 199
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