Einfluss ökologischer Bewirtschaftung und verschiedener Kulturen auf die Regenwurmfauna

Problemstellung/Ziele:Vorkommen und Artenzusammensetzung der Regenwurmpopulation haben eine grosse Bedeutung im nachhaltigen Ackerbau. Als Architekten und Bauarbeiter des Bodens beeinflussen die Regenwürmer verschiedene Parameter der Bodenfruchtbarkeit und damit das Wachstums der Kulturpflanzen. Der Landwirt beeinflusst das Regenwurmvorkommen bei vorgegebenem Standort und Fruchtfolge vor allem durch Bewirtschaftungsmassnahmen wie Düngung, Pflanzenschutz und Bodenbearbeitung. Um Richtung und Ausmass dieser Einflüsse zu erkennen untersuchten wir von 1997 bis 2001 die Regenwurmpopulationen im ökologischen und den integrierten Anbausystemen des Vergleichsversuches Burgrain (D. Dubois, 1999). Fazit: Ökologische Bewirtschaftung förderte auf Burgrain spezifisch das Vorkommen von anözischen Lumbricus und endogäischen Arten; hingegen nicht das Vorkommen von anözischen Nicodrilus Arten. Letztere wurden hingegen sehr deutlich durch die kulturbedingten Bewirtschaftungsmassnahmen beeinflusst. Besonders das Pflügen im Oktober vor Winterweizen wirkte sich negativ auf die tiefgrabenden anözischen Nicodrilus Arten aus. Hier gilt es Verbesserungsmöglichkeiten zu prüfen

Einfluss des Anbausystems auf Ertrag und Gesundheit von Winterweizen

In a long-term trial in central Switzerland, yield and health of winter wheat was examined under organic, extensive and intensive management. In the organic cropping system, soil was ploughed and fertilised with cattle dung. In the extensive system, soil was cultivated ploughless and dung was supplemented by mineral fertiliser. Herbicides were used, but no growth regulators or fungicides. In the intensive system, soil was ploughed and manure was based on cattle dung and mineral fertiliser with 20 % more nitrogen than in the extensive system. For plant protection, herbicides, growth regulators and fungicides were used. In the period from 2004 to 2007, average winter wheat yields of the intensive and the extensive crop management system exceeded those of the organic production by 21.3 % and 5.5 % respectively. This was probably due to the higher level of fertilisation and plant protection. In 2007, a year with frequent rain during the summer, the infestation of grains with Microdochium nivale and Fusarium graminearum was lowest in the organic wheat. In consequence, its germination capacity was higher and the deoxynivalenol content was lower compared with the other systems. The increased grain infestation with F. graminearum and the higher deoxynivalenol content of wheat grains in the extensive system can be explained by the ploughless tillage, with straw from the previous maize crop remaining on the soil surface

Potential loss of nutrients from different rearing strategies for fattening pigs on pasture

Nutrient load and distribution on pasture were investigated with fattening pigs that: 1) spend a proportion of or their entire life on pasture, 2) were fed either restrictively or ad libitum, and 3) were weaned at different times of the year. The N and P retention in pigs decreased the longer they were kept on pasture. The contents of soil inorganic N and exchangeable K were significantly raised compared to the soil outside the enclosures but with no differences between treatments. Pig grazing did not affect extractable soil P. Regular moving of huts, feeding and water troughs was effective in ensuring that nutrients were more evenly distributed on the paddocks. Grass cover, as determined by spectral reflectance, was not related to the experimental treatments but only to time of year. During spring and summer, grass was present in parts of the paddocks, whereas during autumn and winter the pigs kept grass cover below 10%. Fattening pigs on pasture carries a high risk of nutrient loss and it is concluded that the most environmentally acceptable way of keeping fattening pigs on pasture involves a combination of reduced dietary N intake, reduced stocking rate and seasonal rather than all year production

Erträge und Bodenparameter nach 20 Jahren Direktsaat und Pflug

Seit 1994 werden auf der Dauerbeobachtungsfläche Oberacker am Inforama Rütti in Zollikofen auf einem schwach humosen sandigen Lehm die beiden Anbausysteme Direktsaat und Pflug miteinander verglichen. In einem Streifenversuch mit sechs verschiedenen Parzellen werden im Rahmen einer Fruchtfolge die sechs Kulturen Eiweisserbsen – Winterweizen – Ackerbohnen – Wintergerste – Zuckerrüben – Silomais angebaut. Nach 20 Versuchsjahren wurden die Nährstoffversorgung des Bodens untersucht und die Erträge statistisch ausgewertet. Die Bodenproben wurden schichtweise bis in eine Tiefe von 50 cm entnommen und auf organischen Kohlenstoff (Corg), Stickstofftotalgehalt (Ntot), Phosphor (P), Calcium (Ca), Kalium (K), Magnesium (Mg), pH-Wert und Lagerungsdichte untersucht. Im Gegensatz zum Pflugsystem waren bei Direktsaat Corg, Ntot, K und Mg in der obersten Bodenschicht angereichert, der pH-Wert war tiefer und P und Ca zeigten leichte Konzentrationsmaxima bei rund 20 cm Tiefe. Über das ganze Bodenprofil betrachtet war der Vorrat an Corg und allen untersuchten Nährelementen in beiden Systemen vergleichbar hoch. Der über 20 Jahre gemittelte Relativertrag ist bei der Direktsaat im Vergleich zum Pflug um 2,6 % tendenziell, aber nicht signifikant höher. Bei der langjährig auf die Direktsaat abgestimmten Fruchtfolge (ab 2000 ohne Kartoffeln) mit permanenter Bodenbedeckung erbrachten Wintergetreide und Leguminosen im Direktsaatsystem sogar signifikant höhere Erträge als bei gepflügten Böden

Precise Neutron Magnetic Form Factors

Precise data on the neutron magnetic form factor G_{mn} have been obtained with measurements of the ratio of cross sections of D(e,e'n) and D(e,e'p) up to momentum transfers of Q^2 = 0.9 (GeV/c)^2. Data with typical uncertainties of 1.5% are presented. These data allow for the first time to extract a precise value of the magnetic radius of the neutron.Comment: 10 pages, 2 figures, submitted to Physics Letters

Automated detection of atrial fibrillation using long short-term memory network with RR interval signals

Atrial Fibrillation (AF), either permanent or intermittent (paroxysnal AF), increases the risk of cardioembolic stroke. Accurate diagnosis of AF is obligatory for initiation of effective treatment to prevent stroke. Long term cardiac monitoring improves the likelihood of diagnosing paroxysmal AF. We used a deep learning system to detect AF beats in Heart Rate (HR) signals. The data was partitioned with a sliding window of 100 beats. The resulting signal blocks were directly fed into a deep Recurrent Neural Network (RNN) with Long Short-Term Memory (LSTM). The system was validated and tested with data from the MIT-BIH Atrial Fibrillation Database. It achieved 98.51% accuracy with 10-fold cross-validation (20 subjects) and 99.77% with blindfold validation (3 subjects). The proposed system structure is straight forward, because there is no need for information reduction through feature extraction. All the complexity resides in the deep learning system, which gets the entire information from a signal block. This setup leads to the robust performance for unknown data, as measured with the blind fold validation. The proposed Computer-Aided Diagnosis (CAD) system can be used for long-term monitoring of the human heart. To the best of our knowledge, the proposed system is the first to incorporate deep learning for AF beat detection

The Q2Q^2-dependence of the generalised Gerasimov-Drell-Hearn integral for the deuteron, proton and neutron

The Gerasimov-Drell-Hearn (GDH) sum rule connects the anomalous contribution to the magnetic moment of the target nucleus with an energy-weighted integral of the difference of the helicity-dependent photoabsorption cross sections. The data collected by HERMES with a deuterium target are presented together with a re-analysis of previous measurements on the proton. This provides a measurement of the generalised GDH integral covering simultaneously the nucleon-resonance and the deep inelastic scattering regions. The contribution of the nucleon-resonance region is seen to decrease rapidly with increasing $Q^2$. The DIS contribution is sizeable over the full measured range, even down to the lowest measured $Q^2$. As expected, at higher $Q^2$ the data are found to be in agreement with previous measurements of the first moment of $g_1$. From data on the deuteron and proton, the GDH integral for the neutron has been derived and the proton--neutron difference evaluated. This difference is found to satisfy the fundamental Bjorken sum rule at $Q^2 = 5$ GeV$^2$.Comment: 12 pages, 10 figure

Flavor decomposition of the sea quark helicity distributions in the nucleon from semi-inclusive deep-inelastic scattering

Double-spin asymmetries of semi-inclusive cross sections for the production of identified pions and kaons have been measured in deep-inelastic scattering of polarized positrons on a polarized deuterium target. Five helicity distributions including those for three sea quark flavors were extracted from these data together with re-analyzed previous data for identified pions from a hydrogen target. These distributions are consistent with zero for all three sea flavors. A recently predicted flavor asymmetry in the polarization of the light quark sea appears to be disfavored by the data.Comment: 5 pages, 3 figure

Nuclear Polarization of Molecular Hydrogen Recombined on a Non-metallic Surface

The nuclear polarization of $\mathrm{H}_2$ molecules formed by recombination of nuclear polarized H atoms on the surface of a storage cell initially coated with a silicon-based polymer has been measured by using the longitudinal double-spin asymmetry in deep-inelastic positron-proton scattering. The molecules are found to have a substantial nuclear polarization, which is evidence that initially polarized atoms retain their nuclear polarization when absorbed on this type of surfac