321 research outputs found
Percolation experiment across a 10-year-old interface between Opalinus Clay and Portland concrete
An interface sample between Portland concrete and Opalinus Clay with a contact time of 10 years recovered from a field experiment was investigated by SEM-EDX and X-ray CT. The concrete side showed a large chloride ingress from the claystone alongside a decalcification and an opening of the porosity. Additional XRD, TGA and leaching experiments of the concrete at few centimetres (∼5 cm) away from the interface confirmed the chloride ingress. The interface was then subjected to a long-term percolation experiment accompanied with repeated X-ray CT-scans. Injection of synthetic claystone pore water proceeded into the claystone-part of the sample, and through the concrete part, whereby the outflow was continuously sampled. The bedding joints that were partially desaturated rapidly saturated, while hydraulic conductivity steadily decreased to values similar to unaltered claystone. The analysis of the exfiltrating aliquots shed light on the advective/diffusive properties of water transport and multi-component solute transport
Evaluation of fluopyram for the control of Ditylenchus dipsaci in sugar beet
Fluopyram, a succinate dehydrogenase inhibitor fungicide, has shown potential in controlling Meloidogyne incognita and Rotylenchus reniformis in tomato. The effectiveness of this compound for the control of Ditylenchus dipsaci in sugar beet was evaluated. In this study, laboratory, growth chamber, glasshouse, and field experiments were conducted. In a motility bioassay, the EC50 value was determined with 3.00 μg/ml a.i. after 72 h exposure to fluopyram. The growth chamber experiment did not show any effects on D. dipsaci penetration rate; however, field experiments revealed a positive effect of fluopyram applied at planting in reducing D. dipsaci infectivity. The glasshouse experiment confirmed a limited effect of fluopyram on D. dipsaci population development. Under field conditions, despite a reduction of D. dipsaci penetration rates in spring, fluopyram was not effective in reducing the population development until harvest. Consequently, D. dipsaci densities in plant tissue and soil were high at harvest and not different among treatments. However, root-rot symptoms were significantly reduced at harvest. Fluopyram applied at planting showed good potential to reduce root-rot symptoms caused by D. dipsaci in sugar beet. However, for the long-term reduction of nematode populations in soil, further integrated control measures are needed to reduce the risks of substantial yield losses by D. dipsaci
Micro-X-ray diffraction and chemical mapping of aged interfaces between cement pastes and Opalinus Clay
The safety of a geological repository designed for deep storage of nuclear waste rests on the long-lived isolation properties of the geological environment and the engineered barrier system. To study the chemical and physical behaviour of cementitious/clayey interfaces, such interfaces have been collected during repeat sampling campaigns of the CI Experiment (Cement-Clay Interaction Experiment) at the Mont Terri rock laboratory (St. Ursanne, Switzerland, www.mont-terri.ch) over the last decade. This study focuses on the advanced analysis by µ-XRD mapping to locate and identify the mineral phases on each side of the interface. The hydrates as portlandite, ettringite and C-S-H present in the Portland cement (PC) were dissolved in contact with the Opalinus Clay (OPA) up to different depths (~0.2 mm for portlandite; ~1 mm for ettringite; completely depleted for C-S-H up to 0.1 mm and less visible on a 1-mm-depth) while the ettringite from ESDRED (a low-pH cement type) seems to be destabilized to a larger depth ( ≥ 3 mm ). In contrast to former studies, calcite could not be clearly observed at the interface PC - OPA but was well developed at the interface ESDRED - OPA. The extent of reaction after 10 years is very small in both cases, and dissolution of clay minerals remains below detection. The identification of mineral phases involved in reactions facilitates the understanding of the processes, thus, will help to improve the reactive transport models used to simulate the evolution over long times
Zuckerrüben
In dem Merkblatt wird der biologische Anbau der Zuckerrübe kurz und prägnant beschrieben. Von der Sortenwahl bis zur Ernte und Auslieferung. Diese Publikation schicken wir ihnen als Kopie
Biozuckerrüben
In dem Merkblatt wird der biologische Anbau der Zuckerrübe kurz und prägnant beschrieben. Von der Sortenwahl bis zur Ernte und Auslieferung
Biozuckerrüben
Zuckerrüben gelten als Bodenverbesserer, sind Nährstoffzehrer und nutzen als Tiefwurzler die Vorräte im Unterboden. Zuckerrüben sind eine Bereicherung für getreidebetonte Fruchtfolgen, sind aber arbeitsaufwändig im Anbau. Dank den Erfahrung und Auswertungen aus einigen Jahren Biozuckerrübenanbau in der Schweiz sowie Versuchen der Agroscope ART ist es heute möglich, mit einiger Sicherheit erfolgreich Zuckerrüben biologisch zu kultivieren
EEG Sleep Slow-Wave Activity as a Mirror of Cortical Maturation
Deep (slow wave) sleep shows extensive maturational changes from childhood through adolescence, which is reflected in a decrease of sleep depth measured as the activity of electroencephalographic (EEG) slow waves. This decrease in sleep depth is paralleled by massive synaptic remodeling during adolescence as observed in anatomical studies, which supports the notion that adolescence represents a sensitive period for cortical maturation. To assess the relationship between slow-wave activity (SWA) and cortical maturation, we acquired sleep EEG and magnetic resonance imaging data in children and adolescents between 8 and 19 years. We observed a tight relationship between sleep SWA and a variety of indexes of cortical maturation derived from magnetic resonance (MR) images. Specifically, gray matter volumes in regions correlating positively with the activity of slow waves largely overlapped with brain areas exhibiting an age-dependent decrease in gray matter. The positive relationship between SWA and cortical gray matter was present also for power in other frequency ranges (theta, alpha, sigma, and beta) and other vigilance states (theta during rapid eye movement sleep). Our findings indicate a strong relationship between sleep EEG activity and cortical maturation. We propose that in particular, sleep SWA represents a good marker for structural changes in neuronal networks reflecting cortical maturation during adolescenc
Paravalvular leakage after mitral valve replacement: improved long-term survival with aggressive surgery?
Background: Following mitral valve replacement, surgical closure of paravalvular leaks is usually advised in severely symptomatic patients and in those requiring blood transfusions for persisting haemolysis. However, the long-term prognosis of less symptomatic patients or those not needing blood transfusions is unknown. Methods: Between 1987 and 1997, we observed 96 patients with mitral paravalvular leakage. A paraprosthetic leak was diagnosed after a median time of 119 days (range: 1 day-23 years) after primary mitral valve replacement. During an average follow-up of 5 years (range: 1-23 years), 50/96 patients were referred for surgical closure. Results: Compared with patients who received conservative treatment, those referred for surgery had a significantly lower mean preoperative haematocrit (P=0.002) with a higher proportion of patients being in the NYHA class III/IV (P=0.03). Age, gender, left ventricular function and number and size of leaks did not differ between the groups. The 30-day postoperative mortality for valve reoperation was 6% (3/50); during follow-up three further patients died, resulting in an overall mortality rate of 12%. In the group treated conservatively there was a mortality rate of 26% (12/46). Thus, the actuarial survival for patients referred for surgery was 98, 90 and 88% after 1, 5 and 10 years, compared with 90, 75 and 68% for patients treated conservatively (long-rank P=0.03). In addition, there was a significant increase in mean haematocrit levels (P=0.0001) and an improvement in NYHA class III/IV symptoms (P=0.002), vertigo (P=0.001) and fatigue (P=0.001) after surgery. Conclusions: Following mitral valve replacement, a more aggressive surgical treatment is recommended for patients with paraprosthetic leaks. Surgery should be offered to less symptomatic patients, as well as those not requiring blood transfusio
Impacts of Forest Management on Forest Bird Occurrence Patterns-A Case Study in Central Europe
The global increase in demand for wood products, calls for a more sustainable management of forests to optimize both the production of wood and the conservation of forest biodiversity. In this paper, we evaluate the status and future trends of forest birds in Central European forests, assuming different forest management scenarios that to a varying degree respond to the demand for wood production. To this end, we use niche models (Boosted Regression Trees and Generalized Linear Models) to model the responses of 15 forest bird species to predictors related to forest stand (e.g., stand volume of specific tree species) and landscape structure (e.g., percentage cover), and to climate (bioclimatic variables). We then define five distinct forest management scenarios, ranging from set-aside to productivity-driven scenarios, project them 100 years into the future, and apply our niche models into these scenarios to assess the birds' responses to different forest management alternatives. Our models show that the species' responses to management vary reflecting differences in their ecological niches, and consequently, no single management practice can benefit all species if applied across the whole landscape. Thus, we conclude that in order to promote the overall forest bird species richness in the study region, it is necessary to manage the forests in a multi-functional way, e.g., by spatially optimizing the management practices in the landscape
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