169 research outputs found
Germany’s decision to phase out nuclear power is fundamentally sensible from an economic perspective
No full textGermany has made a formal commitment to phase out the use of nuclear power by 2022. Erik Gawel and Sebastian Strunz write on the implications of the strategy for Germany’s future energy mix and whether the approach adopted in the country could function as a model for other European states. They argue that while the target is undeniably challenging, long-term it is economically sensible and feasible to phase out both fossil fuels and nuclear energy in favour of renewables
Is conceptual vagueness an asset? Resilience research from the perspective of philosophy of science
No full textI analyze the research on social-ecological resilience from the perspective of philosophy of science in three steps. First, I explore to what degree resilience research exhibits conceptual vagueness. I find a wide spectrum of research, ranging from approaches relying on a concise conceptual framework to the perspective of “resilience thinking”, which builds on a cluster of vague concepts. Second, I set out the methodological arguments in favor and against conceptual vagueness. Merging both strands of reasoning in the third step, I conclude that a trade-off between vagueness and precision exists, which is to be solved differently depending on the context of resilience research. In some contexts, resilience research benefits from conceptual vagueness while in others it depends on precision. Specifically, I argue that in “resilience thinking” the trade-off might be enhanced by a coherent restructuring of the conceptual framework.vagueness, philosophy of science, precision, resilience thinking, socialecological systems
The economic insurance value of ecosystem resilience
No full textEcosystem resilience, i.e. an ecosystem’s ability to maintain its basic functions and controls under disturbances, is often interpreted as insurance: by decreasing the probability of future drops in the provision of ecosystem services, resilience insures risk-averse ecosystem users against potential welfare losses. Using a general and stringent definition of “insurance” and a simple ecological-economic model, we derive the economic insurance value of ecosystem resilience and study how it depends on ecosystem properties, economic context, and the ecosystem user’s risk preferences. We show that (i) the insurance value of resilience is negative (positive) for low (high) levels of resilience, (ii) it increases with the level of resilience, and (iii) it is one additive component of the total economic value of resilience.ecosystem, economic value, insurance, resilience, risk, risk preferences
Energiewende und größere Energieautarkie: Kann beides erreicht werden?
No full textNeben dem Klimaschutz ist die Minderung der Importabhängigkeit bei fossilen Energieträgern ein Ziel der Energiepolitik Deutschlands. Wie wirkt sich die Energiewende auf die Importabhängigkeit aus? Ist eine Importabhängigkeit im Energiebereich überhaupt ein Problem? Nach Ansicht von Sebastian Strunz und Erik Gawel, Helmholtz-Zentrum für Umweltforschung, Universität Leipzig, hat die Energiewende kein »Importabhängigkeitsproblem«. So sei die in der Vergangenheit entstandene Abhängigkeit gerade von russischen Gasimporten nicht den Energiewendezielen anzulasten. Um dennoch Erdgas nicht zur »Achillesferse« der Energiewende werden zu lassen, sollte kurz- und mittelfristig eine Diversifizierung des Angebots eingeleitet sowie langfristig andere Flexibilitätsoptionen angereizt werden. Für Hubertus Bardt, Institut der deutschen Wirtschaft Köln, ist die Energiewende strukturell auf einen internationalen Ausgleich und offene Strommärkte angewiesen und kann nicht auf Grundlage der Vorstellung einer autarken Energieversorgung gelingen. Von grundlegender Bedeutung sei hier vor allem eine stärkere Europäisierung der Energie- und Strompolitik. Das Konzept der Energieautarkie zeige in die falsche Richtung. Die Chancen der internationalen Arbeitsteilung müssten genutzt werden, um die Energiewende erfolgreich gestalten zu können. Andreas Seeliger, Hochschule Niederrhein, unterstreicht, dass Wirtschaftlichkeit, Umweltverträglichkeit und Versorgungssicherheit die relevanten Zielgrößen sind und in diesem Zusammenhang die Energiewende nur ein Instrument bzw. einen Instrumentenmix ist. Auch zeige das Beispiel der USA, dass Energiewende und Energieautarkie gleichzeitig erreichbar seien. Zwar sei ein abschließendes Fazit noch nicht möglich, nach aktuellem Stand dürfte aber die Energiewende zulasten einer größeren Energieautarkie führen. Die Politik sollte deshalb bei zukünftigen Maßnahmen eine Verschiebung hin zu einer etwas ausgeglicheneren Zielgewichtung anstreben. Sibyl D. Steuwer, FU Ber
Human innate lymphocytes in host defense, tissue function and reproduction
No full textThe immune system is present in all tissues of the human body. In order to respond appropriately to infections, cells of the innate and adaptive immune system work in concert. In this thesis, we focused on natural killer cells (NK cells) and mucosa associated invariant T cells (MAIT cells), that are both present in peripheral blood and enriched in certain tissues such as the liver and, in case of NK cells, also the uterus where they are thought to be important regulators at the maternal-fetal interface. NK cells are able to react readily towards, among other things, virus-infected cells whereas MAIT cells are triggered by both cytokines in viral infections and bacterial metabolites during bacterial infections.Hepatitis C virus (HCV) is a major cause of chronic viral hepatitis and is known to impact the immune system at several instances in order to establish chronic infection. Yet, with recent advances in anti-viral treatment, the infection can now be cured in a short period of time. As a result of this, it is possible to study the impact of HCV on the immune system in a dynamic setting. Therefore we investigated both NK cells and MAIT cells in HCV before, during, and after viral clearance of the infection. Despite rapid clearance of virus, imprints inflicted by chronic HCV infection remained within NK cells and MAIT cells over time. More specifically, MAIT cells were dysfunctional, present at a reduced frequency, and displayed an altered phenotype that was only partially restored upon infection clearance. Along similar lines, also the NK cell phenotype and the diversity of the NK cell compartment remained altered after rapid HCV viral clearance. We observed persistently reduced intraindividual diversity of NK cells after elimination of chronic HCV, whereas the interindividual diversity, more linked to liver damage, was restored over time.Next, we studied peritoneal MAIT cells in ascites of patients with liver cirrhosis on the basis of viral hepatitis and other causes, and in the context of spontaneous bacterial peritonitis (SBP), a frequent and severe complication occurring in these patients. First, we could recapitulate the loss of MAIT cells in peripheral blood of cirrhosis patients in line with previous studies. Of note, in ascites, MAIT cells were more frequent than in blood and displayed a tissue-residency phenotype with increased functionality as compared to peripheral blood MAIT cells. Strikingly, during SBP, MAIT cells were the most recruited immune cells to the peritoneal cavity. Lastly, we investigated uterine NK cells (uNK cells) and hypothesized that these cells underwent a stepwise differentiation in response to endometrial regeneration and pregnancy. We present a model where uNK cells continuously differentiate throughout the menstrual cycle. This differentiation was associated with a functional shift towards immunomodulation and enhanced angiogenic function, possibly to aid in spiral artery formation during pregnancy.In conclusion, we present data suggesting that chronic infections can leave a long-lasting imprint on the immune system. We further demonstrate that immune cell frequency, phenotype, and function can be altered depending on the respective tissue the cells reside in. This work increases our understanding of how innate lymphocytes respond to environmental cues, such as acute or chronic viral and bacterial challenges, as well as to normal physiological processes of the human body.List of scientific papersI. Julia Hengst*, Benedikt Strunz*, Katja Deterding, Hans-Gustaf Ljunggren, Edwin Leeansyah, Michael P. Manns Markus Cornberg, Johan K. Sandberg, Heiner Wedemeyer* and Niklas K. Björkström*. Nonreversible MAIT cell-dysfunction in chronic hepatitis C virus infection despite successful interferon-free therapy. European Journal of Immunology. 2016, vol. 46 (9), pp. 2204-22010. *Contributed equally. https://doi.org/10.1002/eji.201646447 II. Benedikt Strunz*, Julia Hengst*, Katja Deterding, Michael P. Manns, Markus Cornberg, Hans-Gustaf Ljunggren, Heiner Wedemeyer* & Niklas K. Björkström*. Chronic hepatitis C virus infection irreversibly impacts human natural killer cell repertoire diversity. Nature Communications. 2018, vol. 9 (1), pp. 2275-12. *Contributed equally. https://doi.org/10.1038/s41467-018-04685-9 III. Christian E. Niehaus*, Benedikt Strunz*, Martin Cornillet, Christine S. Falk, Ansgar Schnieders, Benjamin Maasoumy, Svenja Hardtke, Michael P. Manns, Anke R.M. Kraft*, Niklas K. Björkström*, Markus Cornberg*. MAIT cells are enriched and highly functional in ascites of patients with decompensated liver cirrhosis. Hepatology. 2020, vol. 72 (4), pp. 1378-1393. *Contributed equally. https://doi.org/10.1002/hep.31153 IV. Benedikt Strunz, Jonna Bister, Russell S. Hamilton, Hanna Jönsson, Ylva Crona-Guterstam, Egle Kvedaraite, Iva Filipovic, Natalie Sleiers, Bogdan Dumitrescu, Danielle Friberg, Mats Brännström, Antonio Lentini, Björn Reinius, Martin Cornillet, Tim Willinger, Sebastian Gidlöf, Martin A. Ivarsson, and Niklas K. Björkström. Continuous human uterine NK cell differentiation in response to endometrial regeneration and pregnancy. [Manuscript]</p
Klimaabgabe für Kohlekraftwerke: Ein richtiger Schritt zur Erreichung des Klimaziels?
No full textLange Zeit favorisierte das Bundesministerium für Wirtschaft und Energie eine zusätzliche Klimaabgabe für alte Kohlekraftwerke zur Erreichung der deutschen Klimaziele. Mit dem Kompromiss vom 1. Juli scheint dieser Vorschlag jetzt vom Tisch zu sein. Sind die Alternativvorschläge zur Erreichung der mittel- bis langfristigen klimapolitischen Ziele effektiver? Für Erik Gawel und Sebastian Strunz, Helmholtz-Zentrum für Umweltforschung – UFZ, Leipzig, ist die vom Koalitionsausschuss favorisierte Variante »die schlechteste« – ohne Stilllegung von CO2-Zertifikaten würden Altkraftwerke in einer überdies kurz- und mittelfristig gar nicht benötigten Kapazitätsreserve gehalten, die strukturellen Anreize für den Stromsektor dürften stark begrenzt sein. Der ursprüngliche Vorschlag des Bundeswirtschaftsministeriums hätte dagegen emissionsintensive Kraftwerke belastet, samt Stilllegung von Zertifikaten. So wäre der jüngsten Renaissance der Braunkohleverstromung strukturell entgegengesteuert worden. Auch nach Ansicht von Sonja Peterson, Institut für Weltwirtschaft an der Universität Kiel, gehen die Vorschläge, die jetzt alternativ zur Klimaabgabe diskutiert werden, in die falsche Richtung: »Sie kosten die deutschen Steuerzahler viel Geld, vergrößern die Ineffizienzen in Deutschland und der EU und sparen am Ende EU-weit keinerlei Emissionen ein.« Die diskutierte Klimaabgabe gehe immerhin in die richtige Richtung. Für Hartmut Möllring, Minister für Wissenschaft und Wirtschaft in Sachsen-Anhalt, ist dagegen die Ablehnung des Klimabeitrags »eine gute Nachricht«. Der angedachte Klimabeitrag sei ordnungspolitisch und verfassungsrechtlich bedenklich, ohne dass damit tatsächlich ein Beitrag zum Klimaschutz geleistet worden wäre. Carl-Friedrich Elmer, Martin Faulstich und Christian Hey, Sachverständigenrat für Umweltfragen (SRU), sehen in den an Stelle des Klimabeitrags beschlossenen Alternativen weniger effiziente und effektive Einzelmaßnahmen. Dessen ungeachtet könnte aber der Klimabeitra
Exploring human uterine immune cell dynamics with a focus on natural killer cells and mait cells
No full textThe uterine immune system is crucial for the establishment of a healthy pregnancy and further development of the embryo. Although a lot is known about endometrial immune cell frequencies, phenotype, and function there are several aspects of the endometrial immune system that remain unknown. In this thesis, I explored several different aspects of the uterine immune system.In paper I, we investigated the dynamics of endometrial mucosal associated invariant T cells (MAIT) cells in various reproductive states and assessed their ability to react to the sexually transmitted bacteria Neisseria gonorrhoeae. In addition, we examined the tissue-residency properties of endometrial MAIT cells using unique human samples obtained after uterus transplantation.In paper II, we conducted a twin study to investigate what drives baseline differences in the endometrial immune system between healthy individuals. The results provide understanding of how the uterine immune cells respond to environmental factors and change through the course of a woman’s life. We found that there is more immune variation in immune cells of the endometrium compared to blood immune cells and that the differences are driven by distinct factors.In paper III, we explored uterine NK (uNK) cell differentiation in relation to the endometrial regeneration occurring during the menstrual cycle and pregnancy. Our findings reveal that uNK cells differentiate continuously throughout the menstrual cycle, with a notable shift towards enhanced angiogenic function and immunomodulatory properties. This functional shift could potentially aid in spiral artery formation during early pregnancy.In summary, this thesis provides valuable new insights into reproductive immunology and explains various aspects of the function of the uterine immune system.LIST OF SCIENTIFIC PAPERSI. Jonna Bister, Ylva Crona-Guterstam, Benedikt Strunz, Bogdan Dumitrescu, Karin Haij Bhattarai, Volkan Özenci, Mats Brännström, Martin A. Ivarsson, Sebastian Gidlöf, and Niklas K. Björkström. Human endometrial MAIT cells are transiently tissue resident and respond to Neisseria gonorrhoeae. Mucosal Immunology, 2021, vol.14 (2), pp. 357-365 https://doi.org/10.1038/s41385-020-0331-5II. Jonna Bister, Iva Filipovic*, Dan Sun*, Ylva Crona-Guterstam, Martin Cornillet, Andrea Ponzetta, Jakob Michaëlsson, Sebastian Gidlöf, Martin A. Ivarsson, Benedikt Strunz, and Niklas K. Björkström. Tissue-specific nonheritable influences drive endometrial immune system variation. Science Immunology, 2024, vol. 9 (94), eadj7168 https://doi.org/10.1126/sciimmunol.adj7168III. Benedikt Strunz, Jonna Bister, Russell S. Hamilton, Hanna Jönsson, Ylva Crona-Guterstam, Egle Kvedaraite, Iva Filipovic, Natalie Sleiers, Bogdan Dumitrescu, Danielle Friberg, Mats Brännström, Antonio Lentini, Björn Reinius, Martin Cornillet, Tim Willinger, Sebastian Gidlöf, Martin A. Ivarsson, and Niklas K. Björkström. Continuous human uterine NK cell differentiation in response to endometrial regeneration and pregnancy. Science Immunology, 2021, vol. 6 (56), eabb7800 https://doi.org/10.1126/sciimmunol.abb7800*These authors contributed equally to the manuscript</p
Is conceptual vagueness an asset? Resilience research from the perspective of philosophy of science
No full textI analyze the research on social-ecological resilience from the perspective of philosophy of science in three steps. First, I explore to what degree resilience research exhibits conceptual vagueness. I find a wide spectrum of research, ranging from approaches relying on a concise conceptual framework to the perspective of resilience thinking, which builds on a cluster of vague concepts. Second, I set out the methodological arguments in favor and against conceptual vagueness. Merging both strands of reasoning in the third step, I conclude that a trade-off between vagueness and precision exists, which is to be solved differently depending on the context of resilience research. In some contexts, resilience research benefits from conceptual vagueness while in othersit depends on precision. Specifically, I argue that in resilience thinking the trade-off might be enhanced by a coherent restructuring of the conceptual framework
Radtke, Jörg, und Norbert Kersting (Hrsg.) (2018): Energiewende. Politikwissenschaftliche Perspektiven
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