Neutron diffraction on purple membranes - Essential water molecules in the light-driven proton pump bacteriorhodopsin

Neutron diffraction and time-resolved laser-spectroscopic experiments on the light-driven proton-pump bacterio-rhodopsin revealed the location of water molecules and their functional importance. About seven water molecules in the proton pathway across this membrane protein were determined at 15% rel. humidity in the ground state

Finding "real people": Trust and diversity in the interface between professional and citizen journalists

The increase of social media and web blogs has enabled a new generation of citizen journalism to provide new perspectives into local communities. However traditional news organisations are currently struggling to incorporate this new form of journalism into their existing organisational workflow. We present an analysis from 10 interviews with professional journalists and explore the current issues faced by professional journalists when searching for reliable and reputable local news sources as well as the perceived role of citizen journalists within a large news organisation. From this analysis we present a set of design implications for building systems that support interaction between citizen and professional journalists in order to encourage participatory news production and diversify national news perspectives

Observations of atmospheric variability and soil exhalation rate of radon-222 at a Russian forest site - Technical approach and deployment for boundary layer studies

A monitor for continuous observations of the atmospheric Rn-222 daughter activity has been improved and successfully implemented in a field study in the European Taiga (Fyodorovskoye Forest Reserve). The alpha-activity of the short-lived Rn-222 and Rn-220 (Pb-212) decay products, which are attached to aerosols, is accumulated on a quartz aerosol filter and assayed on line by alpha-spectroscopy. The alpha-activity from the Pb-212 daughters is determined by spectroscopy and corrected for. This monitor is suitable to measure Rn-222 activities at hourly resolution down to 0.5 Bq m(-3) with an uncertainty well below +/-20%. The prototype of this monitor is run in Heidelberg on the roof of the Institute's building about 20 m above ground. For this site, the atmospheric radioactive disequilibrium was determined between the Rn-222 daughter Po-214 and Rn-222, which has to be known in order to derive the atmospheric Rn-222 activity with the static filter method. We derived a mean disequilibrium Po-214/Rn-222 = 0.704 +/- 0.081 for various meteorological conditions through parallel Rn-222 gas measurements with a slow pulse ionisation chamber. At the Russian field site, continuous activity observations were performed from July 1998 until July 2000 with half a year's interruption in summer/fall 1999. During intensive campaigns, a second monitor was installed at Fyodorovskoye at 15.6 m (July/August 1998), and at 1.8 m (July/August 1999 and October 1999) above ground. As expected, pronounced diurnal cycles of the Rn-222 daughter activity were observed at all sites, particularly during summer when the vertical mixing conditions in the atmospheric surface layer vary strongly between day and night. The lower envelope of the continuous measurements at Fyodorovskoye and at Heidelberg changes on synoptic timescales by a factor of 4-10 due to long-range transport changes between continental to more maritime situations. Generally, the Rn-222 activity at 26.3 m height at Fyodorovskoye is lower by a factor of 2-3 compared to Heidelberg at 20 m above ground. This unexpected result is due to considerably lower Rn-222 exhalation rates from the soils measured in the footprint of the Fyodorovskoye Forest tower compared to Heidelberg. With the inverted chamber technique Rn-222 exhalation rates in the range 3.3-7.9 Bq m(-2) h(-1) were determined at Fyodorovskoye for summer 1998 and autumn 1999 (wet conditions with water table depths between 5 and 70 cm). Only during the very dry summer of 1999 the mean Rn-222 exhalation rate increased by about a factor of five. All measured exhalation rates at the Fyodorovskoye Forest are considerably smaller by a factor of 2-10 compared to observations in the vicinity of Heidelberg (ca 50-60 Bq m(-2) h(-1)) and generally in Western Europe