@techreport{NastanskySiris2024,
  type      = {Working Paper},
  author    = {Nastansky, Andreas and Siris, Sarah},
  title     = {Risikoverbund zwischen Banken und Staaten},
  series = {Statistische Diskussionsbeitr{\"a}ge},
  volume    = {56},
  journal   = {Statistische Diskussionsbeitr{\"a}ge},
  doi       = {10.25932/publishup-61989},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-619891},
  pages     = {50},
  year      = {2024},
  abstract  = {Die Begrenzung systemischer Risiken ist essentieller Bestandteil der neuen internationalen Finanzmarktordnung. Dabei galt es nicht nur die Verflechtung der Banken untereinander, sondern auch die Verbindung zwischen den Staatsfinanzen und der Solvenz der nationalen Bankensysteme (dem sog. Risikoverbund zwischen Staat und Banken) zu durchbrechen. Der Beitrag beleuchtet die Entwicklung der Forderungen gegen{\"u}ber Staaten in den Bankbilanzen der Eurol{\"a}nder und des Eurosystems im Zeitverlauf sowie den daraus erwachsenden Risiken f{\"u}r die Finanzstabilit{\"a}t. Hierzu werden die Determinanten des Risikoverbunds theoretisch wie empirisch analysiert. Die fiskalische Kapazit{\"a}t der Eurostaaten wird anhand verschiedener Faktoren wie der Verschuldungsquote, dem Leistungsbilanzsaldo und der Kredit-BIP L{\"u}cke aufgezeigt; anschließend werden die Strukturen der Bankensysteme im Euroraum untersucht. Im Einzelnen werden die private und staatliche Gesamtverschuldung, die konsolidierte Bankenbilanzsumme und die darin enthaltenen Verbindlichkeiten sowie der Anteil des Bankensektors an der Bruttowertsch{\"o}pfung in Relation zur Wirtschaftsleistung betrachtet. Außerdem finden NPE-Best{\"a}nde in den Bankbilanzen sowie die Renditen der emittierten Staatsanleihen und damit in Verbindung stehenden CDS-Spreads Betrachtung. Zus{\"a}tzlich werden die Konzentration, der Verschuldungsgrad, Liquidit{\"a}tsziffern sowie l{\"a}nderspezifische Unterschiede in Art und Fristigkeit der Refinanzierung der Bankensektoren abgebildet. Auf Basis der empirischen Befunde werden im Hinblick auf die wechselseitigen Ansteckungseffekte zwischen Banken und Staaten Implikationen f{\"u}r die Finanzmarktregulierung diskutiert.},
  language  = {de}
}
@phdthesis{Schifferle2024,
  author    = {Schifferle, Lukas},
  title     = {Optical properties of (Mg,Fe)O at high pressure},
  doi       = {10.25932/publishup-62216},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-622166},
  school      = {Universit{\"a}t Potsdam},
  pages     = {XIV, 90},
  year      = {2024},
  abstract  = {Large parts of the Earth's interior are inaccessible to direct observation, yet global geodynamic processes are governed by the physical material properties under extreme pressure and temperature conditions. It is therefore essential to investigate the deep Earth's physical properties through in-situ laboratory experiments. With this goal in mind, the optical properties of mantle minerals at high pressure offer a unique way to determine a variety of physical properties, in a straight-forward, reproducible, and time-effective manner, thus providing valuable insights into the physical processes of the deep Earth. This thesis focusses on the system Mg-Fe-O, specifically on the optical properties of periclase (MgO) and its iron-bearing variant ferropericlase ((Mg,Fe)O), forming a major planetary building block. The primary objective is to establish links between physical material properties and optical properties. In particular the spin transition in ferropericlase, the second-most abundant phase of the lower mantle, is known to change the physical material properties. Although the spin transition region likely extends down to the core-mantle boundary, the ef-fects of the mixed-spin state, where both high- and low-spin state are present, remains poorly constrained. In the studies presented herein, we show how optical properties are linked to physical properties such as electrical conductivity, radiative thermal conductivity and viscosity. We also show how the optical properties reveal changes in the chemical bonding. Furthermore, we unveil how the chemical bonding, the optical and other physical properties are affected by the iron spin transition. We find opposing trends in the pres-sure dependence of the refractive index of MgO and (Mg,Fe)O. From 1 atm to ~140 GPa, the refractive index of MgO decreases by ~2.4\% from 1.737 to 1.696 (±0.017). In contrast, the refractive index of (Mg0.87Fe0.13)O (Fp13) and (Mg0.76Fe0.24)O (Fp24) ferropericlase increases with pressure, likely because Fe Fe interactions between adjacent iron sites hinder a strong decrease of polarizability, as it is observed with increasing density in the case of pure MgO. An analysis of the index dispersion in MgO (decreasing by ~23\% from 1 atm to ~103 GPa) reflects a widening of the band gap from ~7.4 eV at 1 atm to ~8.5 (±0.6) eV at ~103 GPa. The index dispersion (between 550 and 870 nm) of Fp13 reveals a decrease by a factor of ~3 over the spin transition range (~44-100 GPa). We show that the electrical band gap of ferropericlase significantly widens up to ~4.7 eV in the mixed spin region, equivalent to an increase by a factor of ~1.7. We propose that this is due to a lower electron mobility between adjacent Fe2+ sites of opposite spin, explaining the previously observed low electrical conductivity in the mixed spin region. From the study of absorbance spectra in Fp13, we show an increasing covalency of the Fe-O bond with pressure for high-spin ferropericlase, whereas in the low-spin state a trend to a more ionic nature of the Fe-O bond is observed, indicating a bond weakening effect of the spin transition. We found that the spin transition is ultimately caused by both an increase of the ligand field-splitting energy and a decreasing spin-pairing energy of high-spin Fe2+.},
  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}
}
@techreport{BruttelEisenkopfNithammer2024,
  type      = {Working Paper},
  author    = {Bruttel, Lisa Verena and Eisenkopf, Gerald and Nithammer, Juri},
  title     = {Pre-election communication in public good games with endogenous leaders},
  series = {CEPA Discussion Papers},
  journal   = {CEPA Discussion Papers},
  number    = {73},
  issn      = {2628-653X},
  doi       = {10.25932/publishup-62395},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-623952},
  pages     = {28},
  year      = {2024},
  abstract  = {Leadership plays an important role for the efficient and fair solution of social dilemmas but the effectiveness of a leader can vary substantially. Two main factors of leadership impact are the ability to induce high contributions by all group members and the (expected) fair use of power. Participants in our experiment decide about contributions to a public good. After all contributions are made, the leader can choose how much of the joint earnings to assign to herself; the remainder is distributed equally among the followers. Using machine learning techniques, we study whether the content of initial open statements by the group members predicts their behavior as a leader and whether groups are able to identify such clues and endogenously appoint a "good" leader to solve the dilemma. We find that leaders who promise fairness are more likely to behave fairly, and that followers appoint as leaders those who write more explicitly about fairness and efficiency. However, in their contribution decision, followers focus on the leader's first-move contribution and place less importance on the content of the leader's statements.},
  language  = {en}
}
@techreport{EstrinKhavulKritikosetal.2024,
  type      = {Working Paper},
  author    = {Estrin, Saul and Khavul, Susanna and Kritikos, Alexander and L{\"o}her, Jonas},
  title     = {Access to digital finance},
  series = {CEPA Discussion Papers},
  journal   = {CEPA Discussion Papers},
  number    = {72},
  issn      = {2628-653X},
  doi       = {10.25932/publishup-62326},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-623261},
  pages     = {27},
  year      = {2024},
  abstract  = {Financing entrepreneurship spurs innovation and economic growth. Digital financial platforms that crowdfund equity for entrepreneurs have emerged globally, yet they remain poorly understood. We model equity crowdfunding in terms of the relationship between the number of investors and the amount of money raised per pitch. We examine heterogeneity in the average amount raised per pitch that is associated with differences across three countries and seven platforms. Using a novel dataset of successful fundraising on the most prominent platforms in the UK, Germany, and the USA, we find the underlying relationship between the number of investors and the amount of money raised for entrepreneurs is loglinear, with a coefficient less than one and concave to the origin. We identify significant variation in the average amount invested in each pitch across countries and platforms. Our findings have implications for market actors as well as regulators who set competitive frameworks.},
  language  = {en}
}
@phdthesis{Littmann2024,
  author    = {Littmann, Daniela-Christin},
  title     = {Large eddy simulations of the Arctic boundary layer around the MOSAiC drift track},
  doi       = {10.25932/publishup-62437},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-624374},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xii, 110},
  year      = {2024},
  abstract  = {The icosahedral non-hydrostatic large eddy model (ICON-LEM) was applied around the drift track of the Multidisciplinary Observatory Study of the Arctic (MOSAiC) in 2019 and 2020. The model was set up with horizontal grid-scales between 100m and 800m on areas with radii of 17.5km and 140 km. At its lateral boundaries, the model was driven by analysis data from the German Weather Service (DWD), downscaled by ICON in limited area mode (ICON-LAM) with horizontal grid-scale of 3 km. The aim of this thesis was the investigation of the atmospheric boundary layer near the surface in the central Arctic during polar winter with a high-resolution mesoscale model. The default settings in ICON-LEM prevent the model from representing the exchange processes in the Arctic boundary layer in accordance to the MOSAiC observations. The implemented sea-ice scheme in ICON does not include a snow layer on sea-ice, which causes a too slow response of the sea-ice surface temperature to atmospheric changes. To allow the sea-ice surface to respond faster to changes in the atmosphere, the implemented sea-ice parameterization in ICON was extended with an adapted heat capacity term. The adapted sea-ice parameterization resulted in better agreement with the MOSAiC observations. However, the sea-ice surface temperature in the model is generally lower than observed due to biases in the downwelling long-wave radiation and the lack of complex surface structures, like leads. The large eddy resolving turbulence closure yielded a better representation of the lower boundary layer under strongly stable stratification than the non-eddy-resolving turbulence closure. Furthermore, the integration of leads into the sea-ice surface reduced the overestimation of the sensible heat flux for different weather conditions. The results of this work help to better understand boundary layer processes in the central Arctic during the polar night. High-resolving mesoscale simulations are able to represent temporally and spatially small interactions and help to further develop parameterizations also for the application in regional and global models.},
  language  = {en}
}
@phdthesis{WindirschWoiwode2024,
  author    = {Windirsch-Woiwode, Torben},
  title     = {Permafrost carbon stabilisation by recreating a herbivore-driven ecosystem},
  doi       = {10.25932/publishup-62424},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-624240},
  school      = {Universit{\"a}t Potsdam},
  pages     = {X, 104, A-57},
  year      = {2024},
  abstract  = {With Arctic ground as a huge and temperature-sensitive carbon reservoir, maintaining low ground temperatures and frozen conditions to prevent further carbon emissions that contrib-ute to global climate warming is a key element in humankind's fight to maintain habitable con-ditions on earth. Former studies showed that during the late Pleistocene, Arctic ground condi-tions were generally colder and more stable as the result of an ecosystem dominated by large herbivorous mammals and vast extents of graminoid vegetation - the mammoth steppe. Characterised by high plant productivity (grassland) and low ground insulation due to animal-caused compression and removal of snow, this ecosystem enabled deep permafrost aggrad-ation. Now, with tundra and shrub vegetation common in the terrestrial Arctic, these effects are not in place anymore. However, it appears to be possible to recreate this ecosystem local-ly by artificially increasing animal numbers, and hence keep Arctic ground cold to reduce or-ganic matter decomposition and carbon release into the atmosphere. By measuring thaw depth, total organic carbon and total nitrogen content, stable carbon iso-tope ratio, radiocarbon age, n-alkane and alcohol characteristics and assessing dominant vegetation types along grazing intensity transects in two contrasting Arctic areas, it was found that recreating conditions locally, similar to the mammoth steppe, seems to be possible. For permafrost-affected soil, it was shown that intensive grazing in direct comparison to non-grazed areas reduces active layer depth and leads to higher TOC contents in the active layer soil. For soil only frozen on top in winter, an increase of TOC with grazing intensity could not be found, most likely because of confounding factors such as vertical water and carbon movement, which is not possible with an impermeable layer in permafrost. In both areas, high animal activity led to a vegetation transformation towards species-poor graminoid-dominated landscapes with less shrubs. Lipid biomarker analysis revealed that, even though the available organic material is different between the study areas, in both permafrost-affected and sea-sonally frozen soils the organic material in sites affected by high animal activity was less de-composed than under less intensive grazing pressure. In conclusion, high animal activity af-fects decomposition processes in Arctic soils and the ground thermal regime, visible from reduced active layer depth in permafrost areas. Therefore, grazing management might be utilised to locally stabilise permafrost and reduce Arctic carbon emissions in the future, but is likely not scalable to the entire permafrost region.},
  language  = {en}
}
@techreport{KritikosMalirantaNippalaetal.2024,
  type      = {Working Paper},
  author    = {Kritikos, Alexander and Maliranta, Mika and Nippala, Veera and Nurmi, Satu},
  title     = {Does gender of firm ownership matter?},
  series = {CEPA Discussion Papers},
  journal   = {CEPA Discussion Papers},
  number    = {76},
  issn      = {2628-653X},
  doi       = {10.25932/publishup-63619},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-636194},
  pages     = {1 -- 39},
  year      = {2024},
  abstract  = {We examine how the gender of business-owners is related to the wages paid to female relative to male employees working in their firms. Using Finnish register data and employing firm fixed effects, we find that the gender pay gap is - starting from a gender pay gap of 11 to 12 percent - two to three percentage-points lower for hourly wages in female-owned firms than in male-owned firms. Results are robust to how the wage is measured, as well as to various further robustness checks. More importantly, we find substantial differences between industries. While, for instance, in the manufacturing sector, the gender of the owner plays no role for the gender pay gap, in several service sector industries, like ICT or business services, no or a negligible gender pay gap can be found, but only when firms are led by female business owners. Businesses in male ownership maintain a gender pay gap of around 10 percent also in the latter industries. With increasing firm size, the influence of the gender of the owner, however, fades. In large firms, it seems that others - firm managers - determine wages and no differences in the pay gap are observed between male- and female-owned firms.},
  language  = {en}
}
@techreport{HertelKenneckeReicheetal.2024,
  author    = {Hertel, Kyra and Kennecke, Andreas and Reiche, Michael and Schmidt-Kopplin, Diana and Tillmann, Diana and Winkler, Marco},
  title     = {Bericht zum Auftaktworkshop des Forschungsprojektes "Workflow-Management-Systeme f{\"u}r Open-Access-Hochschulverlage (OA-WFMS)"},
  doi       = {10.25932/publishup-63805},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-638057},
  year      = {2024},
  abstract  = {Das Forschungsprojekt „Workflow-Management-Systeme f{\"u}r Open-Access-Hochschulverlage (OA-WFMS)" ist eine Kooperation zwischen der HTWK Leipzig und der Universit{\"a}t Potsdam. Ziel ist es, die Bedarfe von Universit{\"a}ts- und Hochschulverlagen und Anforderungen an ein Workflow-Management-Systeme (WFMS) zu analysieren, um daraus ein generisches Lastenheft zu erstellen. Das WFMS soll den Publikationsprozess in OA-Verlagen erleichtern, beschleunigen sowie die Verbreitung von Open Access und das nachhaltige, digitale wissenschaftliche Publizieren f{\"o}rdern. Das Projekt baut auf den Ergebnissen der Projekte „Open-Access-Hochschulverlag (OA-HVerlag)" und „Open-Access-Strukturierte-Kommunikation (OA-STRUKTKOMM)" auf. Der diesem Bericht zugrunde liegende Auftaktworkshop fand 2024 in Leipzig mit Vertreter:innen von zehn Institutionen statt. Der Workshop diente dazu, Herausforderungen und Anforderungen an ein WFMS zu ermitteln sowie bestehende L{\"o}sungsans{\"a}tze und Tools zu diskutieren. Im Workshop wurden folgende Fragen behandelt: a. Wie kann die Organisation und {\"U}berwachung von Publikationsprozessen in wissenschaftlichen Verlagen durch ein WFMS effizient gestaltet werden? b. Welche Anforderungen muss ein WFMS erf{\"u}llen, um Publikationsprozesse optimal zu unterst{\"u}tzen? c. Welche Schnittstellen m{\"u}ssen ber{\"u}cksichtigt werden, um die Interoperabilit{\"a}t der Systeme zu garantieren? d. Welche bestehenden L{\"o}sungsans{\"a}tze und Tools sind bereits im Einsatz und welche Vor- und Nachteile haben diese? Der Workshop gliederte sich in zwei Teile : Teil 1 behandelte Herausforderungen und Anforderungen (Fragen a. bis c.), Teil 2 bestehende L{\"o}sungen und Tools (Frage d.). Die Ergebnisse des Workshops fließen in die Bedarfsanalyse des Forschungsprojekts ein. Die im Bericht dokumentierten Ergebnisse zeigen die Vielzahl der Herausforderungen der bestehenden Ans{\"a}tze bez{\"u}glich des OA-Publikationsmanagements . Die Herausforderungen zeigen sich insbesondere bei der Systemheterogenit{\"a}t, den individuellen Anpassungsbedarfen und der Notwendigkeit der systematischen Dokumentation. Die eingesetzten Unterst{\"u}tzungssysteme und Tools wie Dateiablagen, Projektmanagement- und Kommunikationstools k{\"o}nnen insgesamt den Anforderungen nicht gen{\"u}gen, f{\"u}r Teill{\"o}sungen sind sie jedoch nutzbar. Deshalb muss die Integration bestehender Systeme in ein zu entwickelndes OA-WFMS in Betracht gezogen und die Interoperabilit{\"a}t der miteinander interagierenden Systeme gew{\"a}hrleistet werden. Die Beteiligten des Workshops waren sich einig, dass das OA-WFMS flexibel und modular aufgebaut werden soll. Einer konsortialen Softwareentwicklung und einem gemeinsamen Betrieb im Verbund wurde der Vorrang gegeben. Der Workshop lieferte wertvolle Einblicke in die Arbeit der Hochschulverlage und bildet somit eine solide Grundlage f{\"u}r die in Folge zu erarbeitende weitere Bedarfsanalyse und die Erstellung des generischen Lastenheftes.},
  language  = {de}
}
@techreport{BorckMulder2024,
  type      = {Working Paper},
  author    = {Borck, Rainald and Mulder, Peter},
  title     = {Energy policies and pollution in two developing country cities},
  series = {CEPA Discussion Papers},
  journal   = {CEPA Discussion Papers},
  number    = {78},
  issn      = {2628-653X},
  doi       = {10.25932/publishup-63847},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-638472},
  pages     = {37},
  year      = {2024},
  abstract  = {We study the effect of energy and transport policies on pollution in two developing country cities. We use a quantitative equilibrium model with choice of housing, energy use, residential location, transport mode, and energy technology. Pollution comes from commuting and residential energy use. The model parameters are calibrated to replicate key variables for two developing country cities, Maputo, Mozambique, and Yogyakarta, Indonesia. In the counterfactual simulations, we study how various transport and energy policies affect equilibrium pollution. Policies may be induce rebound effects from increasing residential energy use or switching to high emission modes or locations. In general, these rebound effects tend to be largest for subsidies to public transport or modern residential energy technology.},
  language  = {en}
}