827 research outputs found

    ARCADE: Absolute Radiometer for Cosmology, Astrophysics, and Diffuse Emission

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    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

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    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

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    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

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    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

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    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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