ABSTRACT
In this research, we present an alternative methodology to search for ring-like structures in the sky with unusually large temperature gradients, namely, Hawking points (HPs), in the Cosmic ...Microwave Background (CMB), which are possible observational effects associated with Conformal Cyclic Cosmology (CCC). To assess the performance of our method, we constructed an artificial data set of HP, according to CCC, and we were able to retrieve $95 {{\ \rm per\ cent}}$ of ring-like anomalies from it. Furthermore, we scanned the Planck CMB sky map and compared it to simulations according to ΛCDM, where we applied robust statistical tests to assess the existence of HP. Even though no significant ring-like structures were observed, we report the largest excess of HP candidates found at α =1 per cent significance level for the analysed sky maps (CMB at 70GHz, SEVEM, SMICA, and Commander-Ruler), and we stress the need to continue the theoretical and experimental research in this direction.
The aim of the study is to report the frequency of missed diagnoses on magnetic resonance and computerised tomographic imaging in neuro-ophthalmic patients who were referred to an academic ...ophthalmology department, with apparent normal imaging. The authors included all neuro-ophthalmic patients, referred to their department during a 5½-year period. The neuroimaging of these patients were reviewed by a neuro-ophthalmologist side by side with a neuro-radiologist. In the study period, 75 neuro-ophthalmic patients were referred with an apparent normal scan. Re-evaluation of these images gave a diagnosis in 11 patients (15%). Meningiomas were missed most frequently. In half of these patients, no contrast was used in the primary studies. The authors conclude that neuro-ophthalmic pathology can easily be missed on routine neuroimaging studies.
The method of geodesic deviations has been applied to derive accurate analytic approximations to geodesics in Schwarzschild space-time. The results are used to construct analytic expressions for the ...source terms in the Regge-Wheeler and Zerilli-Moncrief equations, which describe the propagation of gravitational waves emitted by a compact massive object moving in the Schwarzschild background space-time. The wave equations are solved numerically to provide the asymptotic form of the wave at large distances for a series of non-circular bound orbits with periastron distances up to the ISCO radius, and the power emitted in gravitational waves by the extreme-mass ratio binary system is computed. The results compare well with those of purely numerical approaches.
The method of geodesic deviations provides analytic approximations to geodesics in arbitrary background space-times. As such the method is a useful tool in many practical situations. In this note we ...point out some subtleties in the application of the method related to secular motions, in first as well as in higher order. In particular we work out the general second-order contribution to bound orbits in Schwarzschild space-time and show that it provides very good analytical results all the way up to the innermost stable circular orbit.
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