Far-infrared transmission studies of c-axis oriented superconducting MgB2 thin film

We reported far-infrared transmission measurements on a c-axis oriented superconducting MgB$_{2}$ thin film in the frequency range of 30 $\sim$ 250 cm$^{-1}$. We found that these measurements were sensitive to values of scattering rate $1/\tau$ and superconducting gap $2\Delta$. By fitting the experimental transmission spectra at 40 K and below, we obtained $1/\tau =$ (700 $\sim$ 1000) cm$^{-1}$ and $2\Delta (0)\cong$ 42 cm$^{-1}$. These two quantities suggested that MgB$_{2}$ belong to the dirty limit.Comment: submitted at May

Geophysical and atmospheric evolution of habitable planets

The evolution of Earth-like habitable planets is a complex process that depends on the geodynamical and geophysical environments. In particular, it is necessary that plate tectonics remain active over billions of years. These geophysically active environments are strongly coupled to a planet's host star parameters, such as mass, luminosity and activity, orbit location of the habitable zone, and the planet's initial water inventory. Depending on the host star's radiation and particle flux evolution, the composition in the thermosphere, and the availability of an active magnetic dynamo, the atmospheres of Earth-like planets within their habitable zones are differently affected due to thermal and nonthermal escape processes. For some planets, strong atmospheric escape could even effect the stability of the atmosphere

Book Review: Mary and Frankenstein, Written By: Linda Bailey, Illustrated By: Júlia Sardà

Abstract. Dust and stars in the plane of the Milky Way create a ”Zone of Avoidance” in the extragalactic sky. Galaxies are distributed in gigantic labyrinth formations, filaments and great walls with occasional dense clusters. They can be traced all over the sky, except where the dust within our own galaxy becomes too thick – leaving about 25 % of the extragalactic sky unaccounted for. Our Galaxy is a natural barrier which constrains the studies of large-scale structures in the Universe, the peculiar motion of our Local Group of galaxies and other streaming motions (cosmic flows) which are important for understanding formation processes in the Early Universe and for cosmological models. Only in recent years have astronomers developed the techniques to peer through the disk and uncover the galaxy distribution in the Zone of Avoidance. I present the various observational multi-wavelength procedures (optical, far infrared, near infrared, radio and X-ray) that are currently being pursued to map the galaxy distribution behind our Milky Way, including a discussion of the (different) limitations and selection effects of these (partly) complementary approaches. The newly unveiled large-scal