The role of humidity and UV-C emission in the inactivation of B. subtilis spores during atmospheric-pressure dielectric barrier discharge treatment

Experiments are performed to assess the inactivation of Bacillus subtilis spores using a non-thermal atmospheric-pressure dielectric barrier discharge. The plasma source used in this study is mounted inside a vacuum vessel and operated in controlled gas mixtures. In this context, spore inactivation is measured under varying nitrogen/oxygen and humidity content and compared to spore inactivation using ambient air. Operating the dielectric barrier discharge in a sealed vessel offers the ability to distinguish between possible spore inactivation mechanisms since different process gas mixtures lead to the formation of distinct reactive species. The UV irradiance and the ozone density within the plasma volume are determined applying spectroscopic diagnostics with neither found to fully correlate with spore inactivation. It is found that spore inactivation is most strongly correlated with the humidity content in the feed gas, implying that reactive species formed, either directly or indirectly, from water molecules are strong mediators of spore inactivation

Modeling and predicting the CBOE market volatility index

The authors are very grateful to financial support from the ESRC under the Grant RES-062-23-0311 (Fernandes) and from CNPq-Brazil (Medeiros), respectively

The drivers of biogeochemistry in beach ecosystems: A cross-shore transect from the dunes to the low water line

This study addresses key processes in high-energy beach systems using an interdisciplinary approach. We assess spatial variations in subsurface pore water residence times, salinity, organic matter (OM) availability, and redox conditions and their effects on nutrient cycles as well as on microbial community patterns and microphytobenthos growth. At the study site on Spiekeroog Island, southern North Sea, beach hydrology is characterized by the classical zonation with an upper saline plume (USP), a saltwater wedge, and a freshwater discharge tube in between. Sediment and pore water samples were taken along a cross-shore transect from the dunes to the low water line reaching sediment depths down to 5 m below sediment surface. Spatial variations in pore water residence time, salinity, and organic matter availability lead to steep redox and nutrient gradients. Vertical and horizontal differences in the microbial community indicate the influence of these gradients and salinity on the community structure. Modeled seawater flux through the USP and freshwater flux through the tube are on average 2.8 and 0.75 m3 per day and meter of shoreline, respectively. Furthermore, ridge sediments at the lower beach discharge seawater at rates of 0.5 and 1.0 m3 per day and meter of shoreline towards the runnel and seaside, respectively. Applying seawater and freshwater fluxes and representative nutrient concentrations for the discharge zones, nutrient fluxes to adjacent nearshore waters are 117 mmol NH4+, 55 mmol PO43 − and 575 mmol Si(OH)4 per day and meter of shoreline. We propose that this nutrient efflux triggers growth of microphytobenthos on sediment surfaces of the discharge zone. A first comparison of nutrient discharge rates of the beach site with a nearby sandy backbarrier tidal flat margin indicates that the beach system might be of less importance in supplying recycled nutrients to nearshore waters than the backbarrier tidal flat area

Enhancing the relevance of Shared Socioeconomic Pathways for climate change impacts, adaptation and vulnerability research

This paper discusses the role and relevance of the shared socioeconomic pathways (SSPs) and the new scenarios that combine SSPs with representative concentration pathways (RCPs) for climate change impacts, adaptation, and vulnerability (IAV) research. It first provides an overview of uses of social–environmental scenarios in IAV studies and identifies the main shortcomings of earlier such scenarios. Second, the paper elaborates on two aspects of the SSPs and new scenarios that would improve their usefulness for IAV studies compared to earlier scenario sets: (i) enhancing their applicability while retaining coherence across spatial scales, and (ii) adding indicators of importance for projecting vulnerability. The paper therefore presents an agenda for future research, recommending that SSPs incorporate not only the standard variables of population and gross domestic product, but also indicators such as income distribution, spatial population, human health and governance

Methoden für die Analyse von kurz-, mittel- und langfristigen Sohlhöhenentwicklungen an der Elbe – Möglichkeiten und Grenzen – Ergänzung Sedimentfracht

Der der "Ergänzung Sedimentfracht" zugrunde liegende Artikel: Reiß, Marcel et al. (2023): "Methoden für die Analyse von kurz-, mittel- und langfristigen Sohlhöhenentwicklungen an der Elbe - Möglichkeiten und Grenzen" ist unser diesem Link in HENRY abrufbar: https://hdl.handle.net/20.500.11970/113687Die "Ergänzung Sedimentfracht" wurden von DWA nur online veröffentlicht: https://www.gfa-news.de/news/20230824_00

Methoden für die Analyse von kurz-, mittel- und langfristigen Sohlhöhenentwicklungen an der Elbe – Möglichkeiten und Grenzen

Ergänzender Artikel: Reiß, Marcel et al. (2023): Methoden für die Analyse von kurz-, mittel- und langfristigen Sohlhöhenentwicklungen an der Elbe – Möglichkeiten und Grenzen – Ergänzung Sedimentfracht. Siehe: https://hdl.handle.net/20.500.11970/11368

Inactivation of B. subtilis spores by low pressure plasma—influence of optical filters and photon/particle fluxes on the inactivation efficiency

Inactivation experiments were performed with Bacillus subtilis spores in a low pressure double inductively coupled plasma (DICP) system. Argon, nitrogen and oxygen at 5 Pa were used as feed gas to change the emission spectrum in the range of 100 nm to 400 nm, as well as between radical and metastable densities. Optical filters were applied, to block particles and selected wavelengths from the spores. By determining absolute photon fluxes, the sporicidal efficiency of various wavelength ranges was evaluated. The results showed good agreement with other plasma experiments, as well as with monochromatic light inactivation experiments from a synchrotron. The findings indicated that the inactivation rate constants of broadband plasma emission and monochromatic light were identical, and that no synergistic effect exists. Furthermore, the influence of radicals, ions and metastables on the inactivation efficiency was of minor importance in the set-up used, and radiation was the main reason for spore inactivation