@article{KindermannDoblerNiedeggenetal.2022, author = {Kindermann, Liana and Dobler, Magnus and Niedeggen, Daniela and Chimbioputo Fabiano, Ezequiel and Linst{\"a}dter, Anja}, title = {Dataset on woody aboveground biomass, disturbance losses, and wood density from an African savanna ecosystem}, series = {Data in Brief}, volume = {42}, journal = {Data in Brief}, publisher = {Elsevier}, address = {Amsterdam, Niederlande}, issn = {2352-3409}, doi = {10.1016/j.dib.2022.108155}, pages = {1 -- 16}, year = {2022}, abstract = {This dataset comprises tree inventories and damage assessments performed in Namibia's semi-arid Zambezi Region. Data were sampled in savannas and savanna woodlands along steep gradients of elephant population densities to capture the effects of those (and other) disturbances on individual-level and stand-level aboveground woody biomass (AGB). The dataset contains raw data on dendrometric measures and processed data on specific wood density (SWD), woody aboveground biomass, and biomass losses through disturbance impacts. Allometric proxies (height, canopy diameters, and in adult trees also stem circumferences) were recorded for n = 6,179 tree and shrub individuals. Wood samples were taken for each encountered species to measure specific wood density. These measurements have been used to estimate woody aboveground biomass via established allometric models, advanced through our improved methodologies and workflows that accounted for tree and shrub architecture shaped by disturbance impacts. To this end, we performed a detailed damage assessment on each woody individual in the field. In addition to estimations of standing biomass, our new method also delivered data on biomass losses to different disturbance agents (elephants, fire, and others) on the level of plant individuals and stands. The data presented here have been used within a study published with Ecological Indicators (Kindermann et al., 2022) to evaluate the benefits of our improved methodology in comparison to a standard reference method of aboveground biomass estimations. Additionally, it has been employed in a study on carbon storage and sequestration in vegetation and soils (Sandhage-Hofmann et al., 2021). The raw data of dendrometric measurements can be subjected to other available allometric models for biomass estimation. The processed data can be used to analyze disturbance impacts on woody aboveground biomass, or for regional carbon storage estimates. The data on species-specific wood density can be used for application to other dendrometric datasets to (re-) estimate biomass through allometric models requiring wood density. It can further be used for plant functional trait analyses.}, language = {en} } @article{PerkinsRoseGrossartetal.2021, author = {Perkins, Anita and Rose, Andrew and Grossart, Hans-Peter and Rojas-Jimenez, Keilor Osvaldo and Barroso Prescott, Selva Kiri and Oakes, Joanne M.}, title = {Oxic and Anoxic Organic Polymer Degradation Potential of Endophytic Fungi From the Marine Macroalga, Ecklonia radiata}, series = {Frontiers in Microbiology}, volume = {12}, journal = {Frontiers in Microbiology}, publisher = {Frontiers in microbiology}, address = {Lausanne, Schweiz}, issn = {1664-302X}, doi = {10.3389/fmicb.2021.726138}, pages = {1 -- 13}, year = {2021}, abstract = {Cellulose and chitin are the most abundant polymeric, organic carbon source globally. Thus, microbes degrading these polymers significantly influence global carbon cycling and greenhouse gas production. Fungi are recognized as important for cellulose decomposition in terrestrial environments, but are far less studied in marine environments, where bacterial organic matter degradation pathways tend to receive more attention. In this study, we investigated the potential of fungi to degrade kelp detritus, which is a major source of cellulose in marine systems. Given that kelp detritus can be transported considerable distances in the marine environment, we were specifically interested in the capability of endophytic fungi, which are transported with detritus, to ultimately contribute to kelp detritus degradation. We isolated 10 species and two strains of endophytic fungi from the kelp Ecklonia radiata. We then used a dye decolorization assay to assess their ability to degrade organic polymers (lignin, cellulose, and hemicellulose) under both oxic and anoxic conditions and compared their degradation ability with common terrestrial fungi. Under oxic conditions, there was evidence that Ascomycota isolates produced cellulose-degrading extracellular enzymes (associated with manganese peroxidase and sulfur-containing lignin peroxidase), while Mucoromycota isolates appeared to produce both lignin and cellulose-degrading extracellular enzymes, and all Basidiomycota isolates produced lignin-degrading enzymes (associated with laccase and lignin peroxidase). Under anoxic conditions, only three kelp endophytes degraded cellulose. We concluded that kelp fungal endophytes can contribute to cellulose degradation in both oxic and anoxic environments. Thus, endophytic kelp fungi may play a significant role in marine carbon cycling via polymeric organic matter degradation.}, language = {en} } @article{HauffeRathSchelletal.2021, author = {Hauffe, Robert and Rath, Michaela and Schell, Mareike and Ritter, Katrin and Kappert, Kai and Deubel, Stefanie and Ott, Christiane and J{\"a}hnert, Markus and Jonas, Wenke and Sch{\"u}rmann, Annette and Kleinridders, Andr{\´e}}, title = {HSP60 reduction protects against diet-induced obesity by modulating energy metabolism in adipose tissue}, series = {Molecular Metabolism}, volume = {53}, journal = {Molecular Metabolism}, publisher = {Elsevier}, address = {Amsterdam, Niederlande}, issn = {2212-8778}, doi = {10.1016/j.molmet.2021.101276}, pages = {1 -- 14}, year = {2021}, abstract = {Objective Insulin regulates mitochondrial function, thereby propagating an efficient metabolism. Conversely, diabetes and insulin resistance are linked to mitochondrial dysfunction with a decreased expression of the mitochondrial chaperone HSP60. The aim of this investigation was to determine the effect of a reduced HSP60 expression on the development of obesity and insulin resistance. Methods Control and heterozygous whole-body HSP60 knockout (Hsp60+/-) mice were fed a high-fat diet (HFD, 60\% calories from fat) for 16 weeks and subjected to extensive metabolic phenotyping. To understand the effect of HSP60 on white adipose tissue, microarray analysis of gonadal WAT was performed, ex vivo experiments were performed, and a lentiviral knockdown of HSP60 in 3T3-L1 cells was conducted to gain detailed insights into the effect of reduced HSP60 levels on adipocyte homeostasis. Results Male Hsp60+/- mice exhibited lower body weight with lower fat mass. These mice exhibited improved insulin sensitivity compared to control, as assessed by Matsuda Index and HOMA-IR. Accordingly, insulin levels were significantly reduced in Hsp60+/- mice in a glucose tolerance test. However, Hsp60+/- mice exhibited an altered adipose tissue metabolism with elevated insulin-independent glucose uptake, adipocyte hyperplasia in the presence of mitochondrial dysfunction, altered autophagy, and local insulin resistance. Conclusions We discovered that the reduction of HSP60 in mice predominantly affects adipose tissue homeostasis, leading to beneficial alterations in body weight, body composition, and adipocyte morphology, albeit exhibiting local insulin resistance.}, language = {en} } @article{HauffeRathAgyapongetal.2022, author = {Hauffe, Robert and Rath, Michaela and Agyapong, Wilson and Jonas, Wenke and Vogel, Heike and Schulz, Tim Julius and Schwarz, Maria and Kipp, Anna Patricia and Bl{\"u}her, Matthias and Kleinridders, Andr{\´e}}, title = {Obesity Hinders the Protective Effect of Selenite Supplementation on Insulin Signaling}, series = {Antioxidants}, volume = {11}, journal = {Antioxidants}, edition = {5}, publisher = {MDPI}, address = {Basel, Schweiz}, issn = {2076-3921}, doi = {10.3390/antiox11050862}, pages = {1 -- 16}, year = {2022}, abstract = {The intake of high-fat diets (HFDs) containing large amounts of saturated long-chain fatty acids leads to obesity, oxidative stress, inflammation, and insulin resistance. The trace element selenium, as a crucial part of antioxidative selenoproteins, can protect against the development of diet-induced insulin resistance in white adipose tissue (WAT) by increasing glutathione peroxidase 3 (GPx3) and insulin receptor (IR) expression. Whether selenite (Se) can attenuate insulin resistance in established lipotoxic and obese conditions is unclear. We confirm that GPX3 mRNA expression in adipose tissue correlates with BMI in humans. Cultivating 3T3-L1 pre-adipocytes in palmitate-containing medium followed by Se treatment attenuates insulin resistance with enhanced GPx3 and IR expression and adipocyte differentiation. However, feeding obese mice a selenium-enriched high-fat diet (SRHFD) only resulted in a modest increase in overall selenoprotein gene expression in WAT in mice with unaltered body weight development, glucose tolerance, and insulin resistance. While Se supplementation improved adipocyte morphology, it did not alter WAT insulin sensitivity. However, mice fed a SRHFD exhibited increased insulin content in the pancreas. Overall, while selenite protects against palmitate-induced insulin resistance in vitro, obesity impedes the effect of selenite on insulin action and adipose tissue metabolism in vivo.}, language = {en} } @techreport{LessmannGrunerKalkuhletal.2024, type = {Working Paper}, author = {Lessmann, Kai and Gruner, Friedemann and Kalkuhl, Matthias and Edenhofer, Ottmar}, title = {Emissions Trading with Clean-up Certificates}, series = {CEPA Discussion Papers}, journal = {CEPA Discussion Papers}, number = {79}, issn = {2628-653X}, doi = {10.25932/publishup-64136}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-641368}, pages = {35}, year = {2024}, abstract = {We analyze how conventional emissions trading schemes (ETS) can be modified by introducing "clean-up certificates" to allow for a phase of net-negative emissions. Clean-up certificates bundle the permission to emit CO2 with the obligation for its removal. We show that demand for such certificates is determined by cost-saving technological progress, the discount rate and the length of the compliance period. Introducing extra clean-up certificates into an existing ETS reduces near-term carbon prices and mitigation efforts. In contrast, substituting ETS allowances with clean-up certificates reduces cumulative emissions without depressing carbon prices or mitigation in the near term. We calibrate our model to the EU ETS and identify reforms where simultaneously (i) ambition levels rise, (ii) climate damages fall, (iii) revenues from carbon prices rise and (iv) carbon prices and aggregate mitigation cost fall. For reducing climate damages, roughly half of the issued clean-up certificates should replace conventional ETS allowances. In the context of the EU ETS, a European Carbon Central Bank could manage the implementation of cleanup certificates and could serve as an enforcement mechanism.}, language = {en} } @misc{WernerCiceroneKliegletal.1984, author = {Werner, John S. and Cicerone, Carola M. and Kliegl, Reinhold and DellaRosa, Denise}, title = {Spectral efficiency of blackness induction}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-16897}, year = {1984}, abstract = {The spectral efficiency of blackness induction was measured in three normal trichromatic observers and in one deuteranomalous observer. The psychophysical task was to adjust the radiance of a monochromatic 60-120′ annulus until a 45′ central broadband field just turned black and its contour became indiscriminable from a dark surrounding gap that separated it from the annulus. The reciprocal of the radiance required to induce blackness with annulus wavelengths between 420 and 680 nm was used to define a spectral-efficiency function for the blackness component of the achromatic process. For each observer, the shape of this blackness-sensitivity function agreed with the spectral-efficiency function based on heterochromatic flicker photometry when measured with the same 60-120′ annulus. Both of these functions matched the Commission Internationale de l'Eclairage Vλ function except at short wavelengths. Ancillary measurements showed that the latter difference in sensitivity can be ascribed to nonuniformities of preretinal absorption, since the annular field excluded the central 60′ of the fovea. Thus our evidence indicates that, at least to a good first approximation, induced blackness is inversely related to the spectral-luminosity function. These findings are consistent with a model that separates the achromatic and the chromatic pathways.}, language = {en} } @phdthesis{Ketzer2024, author = {Ketzer, Laura}, title = {The impact of stellar activity evolution on atmospheric mass loss of young exoplanets}, doi = {10.25932/publishup-62681}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-626819}, school = {Universit{\"a}t Potsdam}, pages = {x, 208}, year = {2024}, abstract = {The increasing number of known exoplanets raises questions about their demographics and the mechanisms that shape planets into how we observe them today. Young planets in close-in orbits are exposed to harsh environments due to the host star being magnetically highly active, which results in high X-ray and extreme UV fluxes impinging on the planet. Prolonged exposure to this intense photoionizing radiation can cause planetary atmospheres to heat up, expand and escape into space via a hydrodynamic escape process known as photoevaporation. For super-Earth and sub-Neptune-type planets, this can even lead to the complete erosion of their primordial gaseous atmospheres. A factor of interest for this particular mass-loss process is the activity evolution of the host star. Stellar rotation, which drives the dynamo and with it the magnetic activity of a star, changes significantly over the stellar lifetime. This strongly affects the amount of high-energy radiation received by a planet as stars age. At a young age, planets still host warm and extended envelopes, making them particularly susceptible to atmospheric evaporation. Especially in the first gigayear, when X-ray and UV levels can be 100 - 10,000 times higher than for the present-day sun, the characteristics of the host star and the detailed evolution of its high-energy emission are of importance. In this thesis, I study the impact of stellar activity evolution on the high-energy-induced atmospheric mass loss of young exoplanets. The PLATYPOS code was developed as part of this thesis to calculate photoevaporative mass-loss rates over time. The code, which couples parameterized planetary mass-radius relations with an analytical hydrodynamic escape model, was used, together with Chandra and eROSITA X-ray observations, to investigate the future mass loss of the two young multiplanet systems V1298 Tau and K2-198. Further, in a numerical ensemble study, the effect of a realistic spread of activity tracks on the small-planet radius gap was investigated for the first time. The works in this thesis show that for individual systems, in particular if planetary masses are unconstrained, the difference between a young host star following a low-activity track vs. a high-activity one can have major implications: the exact shape of the activity evolution can determine whether a planet can hold on to some of its atmosphere, or completely loses its envelope, leaving only the bare rocky core behind. For an ensemble of simulated planets, an observationally-motivated distribution of activity tracks does not substantially change the final radius distribution at ages of several gigayears. My simulations indicate that the overall shape and slope of the resulting small-planet radius gap is not significantly affected by the spread in stellar activity tracks. However, it can account for a certain scattering or fuzziness observed in and around the radius gap of the observed exoplanet population.}, language = {en} } @article{DeekenReichertZechetal.2022, author = {Deeken, Friederike and Reichert, Markus and Zech, Hilmar and Wenzel, Julia and Wedemeyer, Friederike and Aguilera, Alvaro and Aslan, Acelya and Bach, Patrick and Bahr, Nadja Samia and Ebrahimi, Claudia and Fischbach, Pascale Christine and Ganz, Marvin and Garbusow, Maria and Großkopf, Charlotte M. and Heigert, Marie and Hentschel, Angela and Karl, Damian and Pelz, Patricia and Pinger, Mathieu and Riemerschmid, Carlotta and Rosenthal, Annika and Steffen, Johannes and Strehle, Jens and Weiss,, Franziska and Wieder, Gesine and Wieland, Alfred and Zaiser, Judith and Zimmermann, Sina and Walter, Henrik and Lenz, Bernd and Deserno, Lorenz and Smolka, Michael N. and Liu, Shuyan and Ebner-Priemer, Ulrich Walter and Heinz, Andreas and Rapp, Michael A.}, title = {Patterns of Alcohol Consumption Among Individuals With Alcohol Use Disorder During the COVID-19 Pandemic and Lockdowns in Germany}, series = {JAMA Network Open}, volume = {5}, journal = {JAMA Network Open}, edition = {8}, publisher = {JAMA Network / American Medical Association}, address = {Chicago, Illinois, USA}, issn = {2574-3805}, doi = {10.1001/jamanetworkopen.2022.24641}, pages = {1 -- 11}, year = {2022}, abstract = {Importance Alcohol consumption (AC) leads to death and disability worldwide. Ongoing discussions on potential negative effects of the COVID-19 pandemic on AC need to be informed by real-world evidence. Objective To examine whether lockdown measures are associated with AC and consumption-related temporal and psychological within-person mechanisms. Design, Setting, and Participants This quantitative, intensive, longitudinal cohort study recruited 1743 participants from 3 sites from February 20, 2020, to February 28, 2021. Data were provided before and within the second lockdown of the COVID-19 pandemic in Germany: before lockdown (October 2 to November 1, 2020); light lockdown (November 2 to December 15, 2020); and hard lockdown (December 16, 2020, to February 28, 2021). Main Outcomes and Measures Daily ratings of AC (main outcome) captured during 3 lockdown phases (main variable) and temporal (weekends and holidays) and psychological (social isolation and drinking intention) correlates. Results Of the 1743 screened participants, 189 (119 [63.0\%] male; median [IQR] age, 37 [27.5-52.0] years) with at least 2 alcohol use disorder (AUD) criteria according to the Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition) yet without the need for medically supervised alcohol withdrawal were included. These individuals provided 14 694 smartphone ratings from October 2020 through February 2021. Multilevel modeling revealed significantly higher AC (grams of alcohol per day) on weekend days vs weekdays (β = 11.39; 95\% CI, 10.00-12.77; P < .001). Alcohol consumption was above the overall average on Christmas (β = 26.82; 95\% CI, 21.87-31.77; P < .001) and New Year's Eve (β = 66.88; 95\% CI, 59.22-74.54; P < .001). During the hard lockdown, perceived social isolation was significantly higher (β = 0.12; 95\% CI, 0.06-0.15; P < .001), but AC was significantly lower (β = -5.45; 95\% CI, -8.00 to -2.90; P = .001). Independent of lockdown, intention to drink less alcohol was associated with lower AC (β = -11.10; 95\% CI, -13.63 to -8.58; P < .001). Notably, differences in AC between weekend and weekdays decreased both during the hard lockdown (β = -6.14; 95\% CI, -9.96 to -2.31; P = .002) and in participants with severe AUD (β = -6.26; 95\% CI, -10.18 to -2.34; P = .002). Conclusions and Relevance This 5-month cohort study found no immediate negative associations of lockdown measures with overall AC. Rather, weekend-weekday and holiday AC patterns exceeded lockdown effects. Differences in AC between weekend days and weekdays evinced that weekend drinking cycles decreased as a function of AUD severity and lockdown measures, indicating a potential mechanism of losing and regaining control. This finding suggests that temporal patterns and drinking intention constitute promising targets for prevention and intervention, even in high-risk individuals.}, language = {en} } @article{BrahmsHeinzelRappetal.2022, author = {Brahms, Markus and Heinzel, Stephan and Rapp, Michael A. and M{\"u}ckstein, Marie and Hortob{\´a}gyi, Tibor and Stelzel, Christine and Granacher, Urs}, title = {The acute effects of mental fatigue on balance performance in healthy young and older adults - A systematic review and meta-analysis}, series = {Acta Psychologica}, volume = {225}, journal = {Acta Psychologica}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1873-6297}, doi = {10.1016/j.actpsy.2022.103540}, pages = {1 -- 13}, year = {2022}, abstract = {Cognitive resources contribute to balance control. There is evidence that mental fatigue reduces cognitive resources and impairs balance performance, particularly in older adults and when balance tasks are complex, for example when trying to walk or stand while concurrently performing a secondary cognitive task. We conducted a systematic literature search in PubMed (MEDLINE), Web of Science and Google Scholar to identify eligible studies and performed a random effects meta-analysis to quantify the effects of experimentally induced mental fatigue on balance performance in healthy adults. Subgroup analyses were computed for age (healthy young vs. healthy older adults) and balance task complexity (balance tasks with high complexity vs. balance tasks with low complexity) to examine the moderating effects of these factors on fatigue-mediated balance performance. We identified 7 eligible studies with 9 study groups and 206 participants. Analysis revealed that performing a prolonged cognitive task had a small but significant effect (SMDwm = -0.38) on subsequent balance performance in healthy young and older adults. However, age- and task-related differences in balance responses to fatigue could not be confirmed statistically. Overall, aggregation of the available literature indicates that mental fatigue generally reduces balance in healthy adults. However, interactions between cognitive resource reduction, aging and balance task complexity remain elusive.}, language = {en} } @article{CorbettSiegelThulin2024, author = {Corbett, Tim and Siegel, Bj{\"o}rn and Thulin, Mirjam}, title = {Towards Pluricultural and Connected Histories}, series = {PaRDeS}, journal = {PaRDeS}, number = {29}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-574-3}, issn = {1614-6492}, doi = {10.25932/publishup-64598}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-645988}, pages = {15 -- 27}, year = {2024}, language = {en} }