During recent years there has been remarkable progress in the understanding and practical use of chlorophyll fluorescence in plant science. This 'renaissance' of chlorophyll fluorescence was induced by the urgent need of applied research (like plant stress physiology, ecophysiology, phytopathology etc.) for quantitative, non-invasive, rapid methods to assess photosynthesis in intact leaves. Recent developments of suitable instrumentation and methodology have substantially increased these possibilities. Actually, a vast amount of knowledge on chlorophyll fluorescence had already accumulated over more than 50 years, since the discovery of the Kautsky effect in 1931 (Kautsky and Hirsch 1931) (for reviews, see e.g., Lavorel and Etienne 1977, Briantais et al. 1986, Renger and Schreiber 1986). On the one hand this knowledge was mechanistic, resulting from biophysically oriented basic research. On the other hand it was phenomenological, originating from applied plant physiological research. Until recently the phenomenology of whole leaf chlorophyll fluorescence appeared far too complex to find serious attention of biophysicists. Thus, for a long time, there was a gap between applied and basic research in chlorophyll fluorescence. Developments in instrumentation (Ogren and Baker 1985, Schreiber 1986, Schreiber et al. 1986) and methodology (Bradbury and Baker 1981, Krause et al. 1982, Quick and Horton 1984, Dietz et al. 1985, Demmig et al. 1987, Weis and Berry 1987, Bilger et al. 1989, Genty et al. 1989) has succeeded in closing this gap and bringing these two disciplines into sufficiently close contact and in mutually stimulating interaction. Consequently the present "renaissance" of chlorophyll fluorescence may be the product of a fruitful dynamic interaction between three different research disciplines, i.e., basic and applied research linked to new developments in instrumentation and methodology (see scheme in Fig. 1). As a result, measuring chlorophyll fluorescence has become a very attractive means of obtaining rapid, semiquantitative information on photosynthesis, used by an increasing number of researchers not only in the laboratory but also in the field. The wide range of possible applications is reflected by the broad spectrum of contributions to this issue of Photosynthesis Research.The progress made in chlorophyll fluorescence instrumentation and methodology has also induced new developments in the adjacent fields of absorbance spectroscopy (e.g., Klughammer et al. or Harbinson et al. in this issue), photoacoustic spectroscopy (e.g., Canaani, Dau and Hansen, Kolbowski et al. or Snel et al. in this issue) and chlorophyll luminescence (delayed fluorescence) (Bilger and Schreiber in this issue). These new developments are expected to play a role in Basic Research Applied Research \/ Instrumentation and Methodology Fig. 1. Stimulating interactions between different fields in chlorophyll fluorescence research, which have resulted in rapid progress during recent years.

The anterior cingulate cortex (ACC) is a critical component of the human mediofrontal neural circuit that monitors ongoing processing in the cognitive system for signs of erroneous outcomes. Here, we show that the consumption of alcohol in moderate doses induces a significant deterioration of the ability to detect the activation of erroneous responses as reflected in the amplitude of brain electrical activity associated with the ACC. This impairment was accompanied by failures to instigate performance adjustments after these errors. These findings offer insights into how the effects of alcohol on mediofrontal brain function may result in compromised performance.

Our data show a considerable decrease in HPA over a 15-yr period of time, both in male and female subjects. Differences between male and female subjects are predominantly caused by differences in time spent in moderate and very vigorous activities. In the course of time, organized sports activities became a relatively more important contributor of weekly HPA.

SUMMARYThe world needs sustainable, efficient, and renewable energy production. We present the plant microbial fuel cell (plant-MFC), a concept that exploits a bioenergy source in situ. In the plant-MFC, plants and bacteria were present to convert solar energy into green electricity. The principal idea is that plants produce rhizodeposits, mostly in the form of carbohydrates, and the bacteria convert these rhizodeposits into electrical energy via the fuel cell. Here, we demonstrated the proof of principle using Reed mannagrass. We achieved a maximal electrical power production of 67 mW m À2 anode surface. This system was characterized by: (1) nondestructive, in situ harvesting of bioenergy; (2) potential implementation in wetlands and poor soils without competition to food or conventional bioenergy production, which makes it an additional bioenergy supply; (3) an estimated potential electricity production of 21 GJ ha À1 year À1 ð5800 kWh ha À1 year À1 Þ in Europe; and (4) carbon neutral and combustion emission-free operation.