Absorption lines from molecular hydrogen ($\rm H_2$) in the spectra of background sources are a powerful probe physical conditions intervening cold neutral medium. At high redshift, $z>2$, $\rm H_2$ conveniently shifted optical domain, allowing use ground-based telescopes to perform high-resolution spectroscopy, which is essential for proper analysis gas. We describe recent observational progre...

The appropriate and safe use of inhaled corticosteroids (ICS) is an important issue in managing asthma, and we read with interest the article by Wales et al (June 1999).1 This is now the seventh report showing increased adrenal suppression with very high doses of fluticasone propionate (FP) compared to budesonide (BUD) in volunteers.2–7 However, normal subjects do not generally receive these do...

The pair-production absorption of high-energy -rays by intergalactic low-energy photons is expected to produce a high-energy cuto in the spectra of sources which is a sensitive function of redshift. We rst discuss the expected absorption coe cient as a function of energy and redshift derived by Stecker and De Jager by making use of a new empirically based calculation of the spectral energy dist...