12061 to 12072 of 13949 results
Some molecules, particularly aromatics, have high molar extinction coefficients at wavelengths in the damaging ultraviolet radiation region of the spectrum between 200 and 400 nm. Thus, under a UV radiation […]
The notion that ultraviolet (UV) fluxes, and thus biologically weighted irradiances, were higher on Archaean Earth than on present-day Earth has been a pervasive influence on thinking concerning the nature […]
Some believe that the planet Mars holds promise as a new home for humankind and that it could become the focus of a large scale colonisation effort at some undefined […]
We used ultraviolet radiation dosimeters to investigate human exposure at two polar latitudes with a 24-h photoperiod: at Rothera Station (UK) (67degreesS) and at a field camp in the Haughton […]
During the past decade new questions in science have emerged that require broad inter-disciplinary approaches. ‘Do asteroids and comets cause extinctions?’ and ‘Was there, or is there, life on Mars?’ […]
[1] We analyze Trimpi signatures during 23 and 24 April 1994 at four sites on or near the Antarctic Peninsula (Palmer, Faraday, Rothera, and Halley) on subionospheric VLF signals received […]
The aa index provides the longest geomagnetic data set that can be used in the analysis of magnetospheric and ionospheric phenomena. All phases of the solar cycle show increases in […]
The 2002 Annual Symposium of the British Ecological Society on Macroecology: reconciling divergent perspectives on large-scale ecological patterns was held at the University of Birmingham, UK from 17 to 19 […]
The HF radar Doppler spectral width boundary (SWB) in the cusp represents a very good proxy for the equatorward edge of cusp ion precipitation in the dayside ionosphere. For intervals […]
[1] We present measurements of the convection electric field in the dayside ionosphere during extended intervals when the interplanetary magnetic field (IMF) has a negative Bz component and a significant […]
Global convection mapping using line-of-sight Doppler velocity data from the Super Dual Auroral Radar Network (SuperDARN) is now an accepted method of imaging high-latitude ionospheric convection. This mapping process requires […]
Recent work has suggested that in highly correlated systems, such as sandpiles, turbulent fluids, ignited trees in forest fires and magnetization in a ferromagnet close to a critical point, the […]