Sortenbedingte Unterschiede der N-Effizienz und Beziehung zum Wurzelwachstums von Weizen (Triticum aestivum L.) unter den Bedingungen des Ökologischen Landbaus

N Uptake at EC 32, 62 and 92 was determined in 6 wheat varieties in field trials under conditions of conventional and organic farming over 3 years. Root growth potential was assessed in a separate trial under controlled conditions. Rank of varieties regarding N-uptake was dependent on yield level of the test environments and was mainly due to differences in uptake during grain filling. In one variety high N uptake potential coincided with high root growth in later growth stages

Anfälligkeit von Leguminosen gegenüber Meloidogyne hapla

Green manure legumes are a necessary element of organic crop rotations. However, they are able to propagate nematodes especially Meloidogyne and Paratylenchus species. The results of a pot experiment showed that plant species of the genera Pisum, Vicia, Trifolium had a higher propagation rate of Meloidogyne hapla than salad Latuca sativa while plant species of the genera Medicago and Melilotus were less susceptible to infestation of nematodes. It is concluded that crop rotation management especially in vegetable production has to consider the different susceptibility of the legumes and further research has to test more species and varieties

Einfluss des Ertragspotentials des Standorts und des Anbausystems auf den Züchtungserfolg bei Weizen in Deutschland

Baking quality is a major problem of wheat production in organic farming in Germany. The main reason is low protein content, but also different gluten characteristics. The aim of our investigations was to verify, whether selection of varieties with special adaptation to organic farming (or OF systems with particular low input) is advantageous. 66 Genotypes of winter wheat (registered German varieties, breeding lines, older varieties and varieties bred for organic farming) were compared in 5 environments over two years. Yield, protein content and quality parameters were assessed. Aptitude to LI- or HI- conditions was determined using intravarietal linear regression. While selection for special adaptation proved to be superior for yield and protein yield, this could not be confirmed for gluten characteristics

Umsetzen praktischer Energiebedarfsforschung in strategischen Energiemodellen

Im folgenden wird zum einen auf die zuvor angesprochenen grundsätzlichen Probleme der Behandlung von "Energiebedarf" in strategischen Energiemodellen eingegangen und zum anderen werden die heute gebräuchlichen Verfahren der modellmäßigen Abbildung des "Energiebedarfs" diskutiert, um dann aus der Sicht desjenigen, der mit Fragen der Energieplanung befaßt ist, Anforderungen an die Energiebedarfsforschung abzuleiten. Zunächst aber seien einige Anmerkungen zum Sinn und Zweck, zu den Möglichkeiten und Grenzen strategischer Energiemodelle gemacht

Generation of unpredictable time series by a Neural Network

A perceptron that learns the opposite of its own output is used to generate a time series. We analyse properties of the weight vector and the generated sequence, like the cycle length and the probability distribution of generated sequences. A remarkable suppression of the autocorrelation function is explained, and connections to the Bernasconi model are discussed. If a continuous transfer function is used, the system displays chaotic and intermittent behaviour, with the product of the learning rate and amplification as a control parameter.Comment: 11 pages, 14 figures; slightly expanded and clarified, mistakes corrected; accepted for publication in PR

Biochemical properties of Paracoccus denitrificans FnrP:Reactions with molecular oxygen and nitric oxide

In Paracoccus denitrificans, three CRP/FNR family regulatory proteins, NarR, NnrR and FnrP, control the switch between aerobic and anaerobic (denitrification) respiration. FnrP is a [4Fe-4S] cluster containing homologue of the archetypal O2 sensor FNR from E. coli and accordingly regulates genes encoding aerobic and anaerobic respiratory enzymes in response to O2, and also NO, availability. Here we show that FnrP undergoes O2-driven [4Fe-4S] to [2Fe-2S] cluster conversion that involves up to 2 O2 per cluster, with significant oxidation of released cluster sulfide to sulfane observed at higher O2 concentrations. The rate of the cluster reaction was found to be ~6-fold lower than that of E. coli FNR, suggesting that FnrP can remain transcriptionally active under microaerobic conditions. This is consistent with a role for FnrP in activating expression of the high O2 affinity cytochrome c oxidase under microaerobic conditions. Cluster conversion resulted in dissociation of the transcriptionally active FnrP dimer into monomers. Therefore, along with E. coli FNR, FnrP belongs to the subset of FNR proteins in which cluster type is correlated with association state. Interestingly, two key charged residues, Arg140 and Asp154, that have been shown to play key roles in the monomer-dimer equilibrium in E. coli FNR are not conserved in FnrP, indicating that different protomer interactions are important for this equilibrium. Finally, the FnrP [4Fe-4S] cluster is shown to undergo reaction with multiple NO molecules, resulting in iron nitrosyl species and dissociation into monomers

Use of an Atrial Lead with Very Short Tip-To-Ring Spacing Avoids Oversensing of Far-Field R-Wave

The AVOID-FFS (Avoidance of Far-Field R-wave Sensing) study aimed to investigate whether an atrial lead with a very short tip-to-ring spacing without optimization of pacemaker settings shows equally low incidence of far-field R-wave sensing (FFS) when compared to a conventional atrial lead in combination with optimization of the programming.Patients receiving a dual chamber pacemaker were randomly assigned to receive an atrial lead with a tip-to-ring spacing of 1.1 mm or a lead with a conventional tip-to-ring spacing of 10 mm. Postventricular atrial blanking (PVAB) was programmed to the shortest possible value of 60 ms in the study group, and to an individually determined optimized value in the control group. Atrial sensing threshold was programmed to 0.3 mV in both groups. False positive mode switch caused by FFS was evaluated at one and three months post implantation.A total of 204 patients (121 male; age 73±10 years) were included in the study. False positive mode switch caused by FFS was detected in one (1%) patient of the study group and two (2%) patients of the control group (p = 0.62).The use of an atrial electrode with a very short tip-to-ring spacing avoids inappropriate mode switch caused by FFS without the need for individual PVAB optimization.ClinicalTrials.gov NCT00512915

Response of ecologically-mediated shallow intertidal shore transitions to extreme hydrodynamic forcing (RESIST)

This paper reports on the preliminary results from a true-to-scale flume experiment carried out to better understand plant and sediment responses, as well as their interactions, under extreme hydrodynamic forcing in shallow coastal salt and brackish water marsh settings. We report here on bed level changes under individual plant seedlings and denser plant arrangements transplanted from seed and field sites on the Scheldt estuary and on the response of vertically extracted sediment cores from two UK field sites with contrasting sediment characteristics and plant species occupying the surface. Due to the relatively recent completion of the experiment in addition to time-consuming, complex data processing and analysis methods more time is required before definitive quantitative results can be reported. Initial insights into the general behaviour of salt marsh sediments under horizontal and vertical wave-driven hydrodynamic forcing, however, confirm marsh surfaces to be highly stable structures, at least during extreme storm surge events

Régulation de l'activité électrique du locus coeruleus et son implication dans la physiologie et la physiopathologie du contrôle moteur

BORDEAUX2-BU Santé (330632101) / SudocSudocFranceF