Jens Berger

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Understanding crop responses to increasing atmospheric CO2 requires knowledge of how their root systems grow, proliferate and function. The effect of elevated CO2 on the growth and proliferation of wheat root system (Triticum aestivum L.), was examined. Two pairs of sister lines of wheat contrasting in vigour (CV97 and CV207) and tillering (7750N and(More)
Pulmonary epithelia of air-breathing vertebrates are covered by a thin, fluid layer that is essential for immune defense and gas diffusion. The composition of this layer is maintained by ion transport mechanisms, including Cl(-) transport. The present study focuses on the function of basolateral Cl(-) channels in Xenopus pulmonary epithelia, since knowledge(More)
In this paper, we identify quality dimensions which are relevant for speech communication services, such as mobile telephony or Voice-over-IP. These include dimensions perceived when listening to degraded speech, talking against echoes, double-talk capabilities, interacting with delay, conversing over channels with time-varying characteristics, and(More)
The impairment factor methodology has been adopted by telecommunication experts (ITU-T, ETSI) for describing the relative impact of telephone transmission degradations on the overall quality of transmitted speech. Input parameters to this methodology are mainly instrumentally measurable characteristics of the transmission path, with the exception of low(More)
This paper describes a new methodology for the speech quality assessment of hands-free terminals and discusses the results of a pilot study performed in 1996 at the Berlin laboratories for speech quality assessment at the Technology Centre of Deutsche Telekom. Up to now, critical speech quality aspects of hands-free terminals are usually assessed with(More)
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