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The Megamaser Cosmology Project (MCP) measures the Hubble Constant by determining geometric distances to circumnuclear 22 GHz H2O megamasers in galaxies at low redshift (z < 0.05) but well into the Hubble flow. In combination with the recent, exquisite observations of the Cosmic Microwave Background by WMAP and Planck, these measurements provide a direct test of the standard cosmological model and constrain the equation of state of dark energy. The MCP is a multi-year project that has recently completed observations and is currently working on final analysis. Based on distance measurements to the first four published megamasers in the sample, the MCP currently determines H0 = 69.3 ± 4.2 km s−1 Mpc−1. The project is finalizing analysis for five additional galaxies. When complete, we expect to achieve a ~4% measurement. Given the tension between the Planck prediction of H0 in the context of the standard cosmological model and astrophysical measurements based on standard candles, the MCP provides a critical and independent geometric measurement that does not rely on external calibrations or a distance ladder.
High-resolution computed tomography (HRCT) is important in the evaluation of cochlear implant candidates. This study examines the accuracy of radiological assessment of cochlear patency in relation to findings at the time of surgery. Older and newer HRCT methods and attending and senior radiologist interpretations are compared in a large series of cochlear implant patients.
Subjects were 50 adults (22 to 74 years) and 31 children (2.4 to 11.7 years) who received either a 3M/House or a Nucleus 22-channel cochlear implant. Attending radiologist reports were obtained by chart review and the scans were re-reviewed for this study by a senior radiologist. Accuracy in detecting cochlear ossification ranged from 86.4 per cent for attending radiologists, with all HRCT scans, to 94.7 per cent for the senior radiologist with newer HRCT scans. False positives were rare, but false negatives did occur. Overall, best results were obtained with newer HRCT scans and a senior radiologist.
Knowledge of the presence and extent of cochlear ossification is important to the implant surgeon and for patient counselling. Technical guidelines and a check list for interpretation of results are presented.
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