This article investigates the interaction of a spherically symmetric massless scalar eld with a strong gravitational eld. It focuses on the propagation of waves in regions outside any horizons. The two factors acting on the waves can be identiied as a redshift and a backscattering. The innuence of backscattering on the intensity of the outgoing radiation is studied and rigorous quantitative upp...

In vivo oxygen measurement is the key to understanding how biological systems dynamically adapt to reductions in oxygen supply. High spatial resolution oxygen imaging is of particular importance because recent studies address the significance of within-tissue and within-cell heterogeneities in oxygen concentration in health and disease. Here, we report a new technique for in vivo molecular imag...

The first image of a Cosmic Web, Lyman Limit System has just been made in HI emission within the Local Group filament connecting M31 and M33. The corresponding HI distribution function is in very good agreement with that of the QSO absorption lines, confirming the 30-fold increase in surface area expected between 10 cm and 10 cm. The critical observational challenge is crossing the “HI desert”,...