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Wind influences the development, architecture and morphology of plant roots and may modify subsequent interactions between plants and soil (plant–soil feedbacks—PSFs). However, information on wind effects on fine root morphology is scarce and the extent to which wind changes plant–soil interactions remains unclear. Therefore, we investigated the effects of two wind intensity levels by manipulating surrounding vegetation height in a grassland PSF field experiment. We grew four common plant species (two grasses and two non-leguminous forbs) with soil biota either previously conditioned by these or other species and tested the effect of wind on root:shoot ratio, fine root morphological traits as well as the outcome for PSFs. Wind intensity did not affect biomass allocation (i.e. root:shoot ratio) in any species. However, fine-root morphology of all species changed under high wind intensity. High wind intensity increased specific root length and surface area and decreased root tissue density, especially in the two grasses. Similarly, the direction of PSFs changed under high wind intensity in all four species, but differences in biomass production on the different soils between high and low wind intensity were marginal and most pronounced when comparing grasses with forbs. Because soils did not differ in plant-available nor total nutrient content, the results suggest that wind-induced changes in root morphology have the potential to influence plant–soil interactions. Linking wind-induced changes in fine-root morphology to effects on PSF improves our understanding of plant–soil interactions under changing environmental conditions.
Die als Digitalisierung bezeichnete umfassende gesellschaftliche bzw. kulturelle Transformation lässt auch das Grundgesetz nicht unberührt. Die Fortentwicklung der Lehre vom Verfassungswandel ermöglicht es, die verfassungsrechtlichen Dynamiken als einen strukturellen Verfassungswandel zu beschreiben, der sich am Leitbild digitaler Souveränität orientiert. Das Leitbild steht für die Verantwortung und die Legitimität des Staates unter den Bedingungen der Digitalisierung. Enrico Peuker entfaltet es exemplarisch in den verfassungsrechtlichen Kontexten der digitalen Infrastrukturen sowie der "digitalen" Grundrechte. Er plädiert für eine erweiterte Lesart der staatlichen Infrastrukturverantwortung als Optimierungsrecht hinsichtlich des Breitbandausbaus und der IT-Sicherheit und verortet die Grundrechtsentwicklungen in einem Drei-Stufen-Modell aus Interpretation, Innovation und Kodifikation.
Permafrost is warming in the northern high latitudes, inducing highly dynamic thaw-related permafrost disturbances across the terrestrial Arctic. Monitoring and tracking of permafrost disturbances is important as they impact surrounding landscapes, ecosystems and infrastructure. Remote sensing provides the means to detect, map, and quantify these changes homogeneously across large regions and time scales. Existing Landsat-based algorithms assess different types of disturbances with similar spatiotemporal requirements. However, Landsat-based analyses are restricted in northern high latitudes due to the long repeat interval and frequent clouds, in particular at Arctic coastal sites. We therefore propose to combine Landsat and Sentinel-2 data for enhanced data coverage and present a combined annual mosaic workflow, expanding currently available algorithms, such as LandTrendr, to achieve more reliable time series analysis. We exemplary test the workflow for twelve sites across the northern high latitudes in Siberia. We assessed the number of images and cloud-free pixels, the spatial mosaic coverage and the mosaic quality with spectral comparisons. The number of available images increased steadily from 1999 to 2019 but especially from 2016 onward with the addition of Sentinel-2 images. Consequently, we have an increased number of cloud-free pixels even under challenging environmental conditions, which then serve as the input to the mosaicking process. In a comparison of annual mosaics, the Landsat+Sentinel-2 mosaics always fully covered the study areas (99.9–100 %), while Landsat-only mosaics contained data-gaps in the same years, only reaching coverage percentages of 27.2 %, 58.1 %, and 69.7 % for Sobo Sise, East Taymyr, and Kurungnakh in 2017, respectively. The spectral comparison of Landsat image, Sentinel-2 image, and Landsat+Sentinel-2 mosaic showed high correlation between the input images and mosaic bands (e.g., for Kurungnakh 0.91–0.97 between Landsat and Landsat+Sentinel-2 mosaic and 0.92–0.98 between Sentinel-2 and Landsat+Sentinel-2 mosaic) across all twelve study sites, testifying good quality mosaic results. Our results show that especially the results for northern, coastal areas was substantially improved with the Landsat+Sentinel-2 mosaics. By combining Landsat and Sentinel-2 data we accomplished to create reliably high spatial resolution input mosaics for time series analyses. Our approach allows to apply a high temporal continuous time series analysis to northern high latitude permafrost regions for the first time, overcoming substantial data gaps, and assess permafrost disturbance dynamics on an annual scale across large regions with algorithms such as LandTrendr by deriving the location, timing and progression of permafrost thaw disturbances
Engineering biotechnological microorganisms to use methanol as a feedstock for bioproduction is a major goal for the synthetic metabolism community. Here, we aim to redesign the natural serine cycle for implementation in E. coli. We propose the homoserine cycle, relying on two promiscuous formaldehyde aldolase reactions, as a superior pathway design. The homoserine cycle is expected to outperform the serine cycle and its variants with respect to biomass yield, thermodynamic favorability, and integration with host endogenous metabolism. Even as compared to the RuMP cycle, the most efficient naturally occurring methanol assimilation route, the homoserine cycle is expected to support higher yields of a wide array of products. We test the in vivo feasibility of the homoserine cycle by constructing several E. coli gene deletion strains whose growth is coupled to the activity of different pathway segments. Using this approach, we demonstrate that all required promiscuous enzymes are active enough to enable growth of the auxotrophic strains. Our findings thus identify a novel metabolic solution that opens the way to an optimized methylotrophic platform.
Formaldehyde is a highly reactive compound that participates in multiple spontaneous reactions, but these are mostly deleterious and damage cellular components. In contrast, the spontaneous condensation of formaldehyde with tetrahydrofolate (THF) has been proposed to contribute to the assimilation of this intermediate during growth on C1 carbon sources such as methanol. However, the in vivo rate of this condensation reaction is unknown and its possible contribution to growth remains elusive. Here, we used microbial platforms to assess the rate of this condensation in the cellular environment. We constructed Escherichia coli strains lacking the enzymes that naturally produce 5,10-methylene-THF. These strains were able to grow on minimal medium only when equipped with a sarcosine (N-methyl-glycine) oxidation pathway that sustained a high cellular concentration of formaldehyde, which spontaneously reacts with THF to produce 5,10-methylene-THF. We used flux balance analysis to derive the rate of the spontaneous condensation from the observed growth rate. According to this, we calculated that a microorganism obtaining its entire biomass via the spontaneous condensation of formaldehyde with THF would have a doubling time of more than three weeks. Hence, this spontaneous reaction is unlikely to serve as an effective route for formaldehyde assimilation.
Medientechnisches Wissen
(2020)
Das mehrbändige Lehrbuch vermittelt Studierenden und Medienwissenschaftlern eine Einführung aus den Naturwissenschaften, Ingenieurwissenschaften und Technik-Disziplinen. Dabei steht im Zentrum, die Lesekompetenz für die jeweilige Disziplin zu etablieren und zu verbessern, damit innerhalb medien- und kulturwissenschaftlicher Studienprogramme Fachtexte der einzelnen Disziplinen diskutiert werden können
Many technical challenges still need to be overcome to improve the quality of the green coffee beans. In this work, the wet Arabica coffee processing in batch and continuous modus were investigated. Coffee beans samples as well as by-products and wastewaters collected at different production steps were analyzed in terms of their content in total phenols, antioxidant capacity, caffeine content, organic acids, reducing sugars, free amino group and protein content. The results showed that 40% of caffeine was removed with pulp. Green coffee beans showed highest concentration of organic acids and sucrose (4.96 ± 0.25 and 5.07 ± 0.39 g/100 g DW for the batch and continuous processing). Batch green coffee beans contained higher amount of phenols. 5-caffeoylquinic Acid (5-CQA) was the main constituent (67.1 and 66.0% for the batch and continuous processing, respectively). Protein content was 15 and 13% in the green coffee bean in batch and continuous processing, respectively. A decrease of 50 to 64% for free amino groups during processing was observed resulting in final amounts of 0.8 to 1.4% in the processed beans. Finally, the batch processing still revealed by-products and wastewater with high nutrient content encouraging a better concept for valorization.
Starch and Glycogen Analyses
(2020)
For complex carbohydrates, such as glycogen and starch, various analytical methods and techniques exist allowing the detailed characterization of these storage carbohydrates. In this article, we give a brief overview of the most frequently used methods, techniques, and results. Furthermore, we give insights in the isolation, purification, and fragmentation of both starch and glycogen. An overview of the different structural levels of the glucans is given and the corresponding analytical techniques are discussed. Moreover, future perspectives of the analytical needs and the challenges of the currently developing scientific questions are included
Fontane als Leser
(2020)
Einführung
(2020)
Henrik Ibsen behandelt in seinem Schauspiel Ein Volksfeind (1882) einen Umweltskandal, was das Stück zeitlos aktuell macht. Heutige Inszenierungen können umstandslos an die hier vorgestellten Umweltprobleme und den Umgang damit in der nach dem Mehrheitsprinzip verfahrenden Demokratie anknüpfen. In dem Beitrag wird zunächst der Begriffsgeschichte von „Volksfeind“ nachgegangen, vom Römischen Reich über die Französische Revolution, die totalitären Diktaturen des 20. Jahrhunderts bis zur heutigen Bundesrepublik und den USA. Im Weiteren werden die im Stück thematisierten Verhältnisse von Mehrheit und Minderheit sowie Macht und Recht im politisch-gesellschaftlichen Gefüge vor dem Hintergrund demokratietheoretischer Überlegungen von Alexis die Tocqueville, John Stuart Mill und Emma Goldman untersucht. Schließlich werden die im Volksfeind aufgeworfenen Fragen nach der Möglichkeit von Bildung und politischer Mündigkeit vor dem Hintergrund heutiger postfaktischer Tendenzen, von Politik mit „alternativen Fakten“, Bullshit und Lügen diskutiert.
Eine relevante und höchst aktuelle Überschneidung fachübergreifender und fachspezifischer sprachlicher Phänomene hat Elisabeth Wehling mit ihrem 2016 erschienenen Buch „Politisches Framing“ einer breiten Öffentlichkeit, die weit über fachwissenschaftliche Kreise hinaus geht, dargelegt. Wehling erläutert darin an zahlreichen Beispielen, dass in politischen Debatten und für ihre Wirkung nicht zuerst die vorgetragenen Fakten entscheidend sind, sondern gedankliche Deutungsrahmen — in den Kognitionswissenschaften Frames genannt — die den Fakten eine Bedeutung verleihen. Informationen werden demnach in Relation zu Erfahrungen und Vorwissen als relevant oder irrelevant eingeordnet sowie durch Frames bewertet und interpretiert. Dadurch beeinflussen Frames — häufig unbewusst — Denken und Handeln. (Wehling, S. 17 ff.) Eine Auseinandersetzung mit den von Wehling dargelegten Erkenntnissen im Rahmen des Politikunterrichts ermöglicht die Entwicklung und Förderung von sprachlicher und fachlicher Kompetenz. Dieser Beitrag fasst die von Wehling dargelegten Erkenntnisse zusammen und erläutert das didaktische Potenzial des Themas Politisches Framing anhand kompetenzbezogener Aufgaben für den Politikunterricht.
Materielle Miniaturen
(2020)
Andere Räume : Pupenhäuser
(2020)
Hilbigs Italienreise
(2020)
Zu Heiner Müllers Paaren
(2020)