We present far-ultraviolet spectra of the Seyfert 1.5 galaxy NGC 5548 obtained in 2000 June with the Far Ultraviolet Spectroscopic Explorer (FUSE). Our data span the observed wavelength range 915–1185 Å at a resolution of ∼ 20 km s. The spectrum shows a weak continuum and emission from O VI λλ1032,1038, C III λ977, and He II λ1085. The FUSE data were obtained when the AGN was in a low state, wh...

The concept of systemic photoprotection by dietary means is gaining momentum. Skin is continuously exposed to ultraviolet (UV) radiation, the major cause of skin disorders such as sunburn, photodamage, and nonmelanoma skin cancer. Most of the erythemal annual UV dose is encountered under nonvacation conditions, when no sunscreen is applied. In the absence of topically added compounds, skin prot...

A new approach to derive tropospheric concentrations of some atmospheric trace gases from ground-based UV/vis measurements is described. The instrument, referred to as the MAX-DOAS, is based on the well-known UV/vis instruments, which use the sunlight scattered in the zenith sky as the light source and the method of Differential 5 Optical Absorption Spectroscopy (DOAS) to derive column amounts ...

The current paradigm for the AGN phenomenon is a central engine that consists of an inflow of material accreting in the form of a disk onto a supermassive black hole. Observations in the UV and optical find high velocity ionized material outflowing from the black hole. We present results from Suzaku and XMM-Newton observations of a sample of intrinsic NAL quasars with high velocity outflows. Ou...

We have modelled the evolution of the number of Lyα absorbers with redshift, resulting from the evolution of the ionising background and the Hubble expansion. The contribution of quasars (QSOs) and galaxies to the H i-ionising UV background has been estimated. The QSOs emissivity is derived from recent fits of their luminosity function. The galaxy emissivity is computed using a stellar populati...

OBJECTIVE Physical UV absorbers such as titanium dioxide or zinc oxide have been found to be highly protective against ultraviolet radiation. Sun protection factor depends on the accumulation of the minerals on the skin. UV-absorbing agents must accumulate within the upper skin layers in order to provide a dense light-absorbing layer and guarantee water resistance. The aim of this work was to i...

Responses of American arborvitae (Thuja occidentalis), common yew (Taxus x media) and juniper (Juniperus communis) to enhanced UV-B irradiance were studied. Control plants were grown without UV treatment, but at identical PhaR and temperature regimes. Visual symptoms of the ultraviolet effect noted on Thuja shoots as brown/red discolouration were correlated with the accumulation of phenolic com...

Ultraviolet spectrographs aboard the Hubble Space Telescope (HST) and the Far Ultraviolet Spectroscopic Explorer (FUSE) have proved their value as sensitive probes of the low-density intergalactic medium (IGM) at low redshifts (z < 0.1). Recent observations in Lyα, Lyβ, and occasional higher Lyman lines show that warm photoionized gas in the low-z IGM may contain 20–25% of the baryons, with a N...