50 research outputs found

    Stability via closure relations with applications to dissipative and port-Hamiltonian systems

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    We consider differential operators A that can be represented by means of a so-called closure relation in terms of a simpler operator Aext defined on a larger space. We analyse how the spectral properties of A and Aext are related and give sufficient conditions for exponential stability of the semigroup generated by A in terms of the semigroup generated by Aext. As applications we study the long-term behaviour of a coupled wave–heat system on an interval, parabolic equations on bounded domains that are coupled by matrix-valued potentials, and of linear infinite-dimensional port-Hamiltonian systems with dissipation on an interval.</p

    Cathodal HD-tDCS above the left dorsolateral prefrontal cortex increases environmentally sustainable decision-making

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    Environmental sustainability is characterized by a conflict between short-term self-interest and longer-term collective interests. Self-control capacity has been proposed to be a crucial determinant of people’s ability to overcome this conflict. Yet, causal evidence is lacking, and previous research is dominated by the use of self-report measures. Here, we modulated self-control capacity by applying inhibitory high-definition transcranial current stimulation (HD-tDCS) above the left dorsolateral prefrontal cortex (dlPFC) while participants engaged in an environmentally consequential decision-making task. The task includes conflicting and low conflicting trade-offs between short-term personal interests and long-term environmental benefits. Contrary to our preregistered expectation, inhibitory HD-tDCS above the left dlPFC, presumably by reducing self-control capacity, led to more, and not less, pro-environmental behavior in conflicting decisions. We speculate that in our exceptionally environmentally friendly sample, deviating from an environmentally sustainable default required self-control capacity, and that inhibiting the left dlPFC might have reduced participants’ ability to do so

    Characterizing expression changes in noncoding RNAs during aging and heterochronic parabiosis across mouse tissues

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    Molecular mechanisms of organismal and cell aging remain incompletely understood. We, therefore, generated a body-wide map of noncoding RNA (ncRNA) expression in aging (16 organs at ten timepoints from 1 to 27 months) and rejuvenated mice. We found molecular aging trajectories are largely tissue-specifc except for eight broadly deregulated microRNAs (miRNAs). Their individual abundance mirrors their presence in circulating plasma and extracellular vesicles (EVs) whereas tissue-specifc ncRNAs were less present. For miR-29c-3p, we observe the largest correlation with aging in solid organs, plasma and EVs. In mice rejuvenated by heterochronic parabiosis, miR-29c-3p was the most prominent miRNA restored to similar levels found in young liver. miR-29c-3p targets the extracellular matrix and secretion pathways, known to be implicated in aging. We provide a map of organism-wide expression of ncRNAs with aging and rejuvenation and identify a set of broadly deregulated miRNAs, which may function as systemic regulators of aging via plasma and EVs

    Ageing-associated small RNA cargo of extracellular vesicles

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    Previous work on murine models and humans demonstrated global as well as tissue-specific molecular ageing trajectories of RNAs. Extracellular vesicles (EVs) are membrane vesicles mediating the horizontal transfer of genetic information between different tissues. We sequenced small regulatory RNAs (sncRNAs) in two mouse plasma fractions at five time points across the lifespan from 2–18 months: (1) sncRNAs that are free-circulating (fc-RNA) and (2) sncRNAs bound outside or inside EVs (EV-RNA). Different sncRNA classes exhibit unique ageing patterns that vary between the fcRNA and EV-RNA fractions. While tRNAs showed the highest correlation with ageing in both fractions, rRNAs exhibited inverse correlation trajectories between the EV- and fc-fractions. For miRNAs, the EV-RNA fraction was exceptionally strongly associated with ageing, especially the miR-29 family in adipose tissues. Sequencing of sncRNAs and coding genes in fat tissue of an independent cohort of aged mice up to 27 months highlighted the pivotal role of miR-29a-3p and miR-29b-3p in ageing-related gene regulation that we validated in a third cohort by RT-qPCR

    Elevated oxysterol levels in human and mouse livers reflect nonalcoholic steatohepatitis

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    Non-alcoholic steatohepatitis (NASH), a primary cause of liver disease, leads to complications such as fibrosis, cirrhosis, and carcinoma, but the pathophysiology of NASH is incompletely understood. Epstein Barr virus induced G protein coupled receptor 2 (EBI2) and its oxysterol ligand 7α,25-dihydroxycholesterol (7α,25-diHC) are recently discovered immune regulators. Several lines of evidence suggest a role of oxysterols in NASH pathogenesis, but rigorous testing has not been performed. We measured oxysterol levels in livers of NASH patients by liquid chromatography-mass spectrometry and tested the role of the EBI2-7α,25-diHC-system in a murine feeding model of NASH. Free oxysterol profiling in livers from NASH patients revealed a pronounced increase in 24- and 7-hydroxylated oxysterols in NASH compared to controls. Levels of 24- and 7-hydroxylated oxysterols correlated with histological NASH activity. Histological analysis of murine liver samples demonstrated ballooning and liver inflammation. No significant genotype related differences were observed in Ebi2-/- animals and animals with defects in the 7α,25-diHC synthesizing enzymes CH25H and CYP7B1 compared to wildtype littermate controls,arguing against an essential role of these genes in NASH pathogenesis. Elevated 24- and 7-hydroxylated oxysterol levels were confirmed in murine NASH liver samples. Our results suggest increased bile acid synthesis in NASH samples, as judged by enhanced level of 7α- hydroxycholest-4-en-3-one, and impaired 24S-hydroxycholesterol metabolism as characteristic biochemical changes in livers affected by NASH

    Digitalisierung beruflicher Lern- und Arbeitsprozesse. Impulse aus der Bauwirtschaft und anderen gewerblich-technischen Sektoren

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    Der Sammelband stellt aktuelle Ansätze zum digital unterstützten beruflichen Lernen dar. Die Beiträge geben Einblicke in die dynamische Entwicklung der Schnittstellen von Erwerbsarbeit und beruflicher Aus-, Fort- und Weiterbildung im Kontext der Digitalisierung Arbeits- und Lernmitteln. Der Band schließt damit an die 2019 ebenfalls im Universitätsverlag der Technischen Universität Berlin erschienene Publikation „Berufsbildung am Bau digital“ (hrsg. von Bernd Mahrin und Johannes Meyser) an. Das erste Kapitel erörtert grundsätzliche didaktische Fragen zu digital unterstütztem Lernen und Arbeiten einschließlich der Rahmenbedingungen. Im zweiten Kapitel schließen sich Beiträge zur Kapazitätsentwicklung, zu Standards und zu digitalen Werkzeugen an. Das dritte Kapitel widmet sich konkreten Einzellösungen mit starkem Praxisbezug und hohem Transferpotenzial zum digitalisierten Arbeiten und Lernen im Bausektor und im Metallbereich. Das abschließende vierte Kapitel präsentiert übergreifend nutzbare und frei zugängliche Online-Angebote wie einen Medienpool für Bildungszwecke, eine Lernmedien-Datenbank und ein hybrides Lernsystem mit virtuellem 3D-Gebäudemodell. Das Buch ist entstanden im Rahmen des durch das Bundesministerium für Bildung und Forschung und den Europäischen Sozialfonds geförderten Projektes DigiBAU – Digitales Bauberufliches Lernen und Arbeiten. (DIPF/Orig.)The anthology presents current approaches to digitally supported professional learning. The articles provide insights into the dynamic development of the interfaces between gainful employment and vocational training and further education in the context of digitization of work and learning aids. The volume is thus connected to the publication “Berufsbildung am Bau digital” (edited by Bernd Mahrin and Johannes Meyser), which was published in 2019 by the University Press of the Technische Universität Berlin. The first chapter discusses fundamental didactic questions about digitally supported learning and working, including the framework conditions. The second chapter picks contributions on capacity development, standards, and digital tools out as central themes. The third chapter is dedicated to concrete specific solutions with strong practical relevance and high transfer potential for digitized work and learning in the construction sector and in the metal sector. The final fourth chapter presents comprehensive and freely accessible online offers such as a media pool for educational purposes, a learning media database and a hybrid learning system with a virtual 3D building model. The book was created as part of the DigiBAU project - digital vocational learning and working in the field of construction - funded by the German Federal Ministry of Education and Research and the European Social Fund. (DIPF/Orig.

    Climate change denial is associated with diminished sensitivity in internalizing environmental externalities

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    Despite a strong scientific consensus about the existence of anthropogenic climate change, widespread scepticism in the general population continues to exist. Past research has largely relied on self-reported behaviours or behavioural intentions when investigating downstream 'behavioural' consequences of climate change denial. As a consequence, there remains a large gap in the literature about how belief in climate change interacts with the pursuit of self-interested, environmentally harmful behaviours. To fill that gap, the present research uses a novel, experimental economic paradigm that allows to attach true environmental consequences to laboratory decisions. Based on ~56 000 pollution decisions from 2273 participants in more than 30 countries, we find that belief in climate change meaningfully affects decision-making. Our results show that climate change scepticism predicts self-interested choices and showcases that sceptics have an insensitive acceptance of emissions, reaping benefits no matter how large the climate cost are or how small the personal benefits become. Therefore, our results critically augment meta-analytic evidence arguing that downstream behavioural consequences are small to medium in their effect size. We discuss the use of experimental economic paradigms as a crucial innovation tool for psychological research addressing people's willingness to engage in climate action
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