28 research outputs found
Energy dependence of pion double charge exchange
The energy dependence of forward angle pion double charge exchange is calculated in the energy range of 0–250 MeV. The most striking feature is a peak around 40 MeV which is in excellent agreement with the data when distorted waves obtained from a realistic optical model are used. Two possible short-range corrections to the reaction mechanism are addressed
The Pion Double Charge Exchange Formalism in Point-Like and Finite Range-Like Pion-Nucleon Interaction
Microstructure and electrical conductivity in shape and size controlled molybdenum particle thick film
Allelopathic Effects of Exotic Tree Species on Microorganisms and Plants in Galicia (Spain)
Allelopathic and autotoxicity effects of barley (Hordeum vulgare L. ssp. vulgare) root exudates
The allelopathic activity of barley (Hordeum vulgare L. ssp. vulgare) root exudates was studied
by comparing their effects on seedling establishment in barley itself and in two weed species, Bromus diandrus Roth. and Lolium rigidum Gaudin, using an original laboratory protocol, named ‘seed-after-seed’. In this protocol, the donor and the receiver species of watersoluble
allelochemicals are grown one after the other in the same dishes, in conditions reducing resource competition between both species. Growth of all receptive species (weeds and barley) was inhibited in a dose-dependent manner, when using increasing barley seed densities (0, 8, 19 and 25 seeds per Petri dish). In our conditions, the barley varieties and landraces exhibited different allelopathic activities against weeds or barley. The allelopathic potential of
the barley root exudates was also dependent on the receiver species. Indeed, the released allelochemicals proved to be more toxic against the weed plants than on barley itself. Furthermore, the toxicity of the allelochemicals increased after their release by roots,
between day 0 and day 6. These allelochemicals might contribute to the plant community dynamics and their usefulness as bio-herbicides deserves further consideration