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a relational framework for simulation modelling
Get PDFThe article processing charge was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – 491192747 and the Open Access Publication Fund of Humboldt-Universität zu Berlin.In this paper we extend the use of a relational approach to simulation modelling, a widely used knowledge practice in sustainability science. Among modellers, there is awareness that model results can only be interpreted in view of the assumptions that inform model construction and analysis, but less systematic questioning of those assumptions. Moreover, current methodological discussions tend to focus on integrating social and ecological dynamics or diverse knowledges and data within a model. Yet choices regarding types of modelling, model structure, data handling, interpretation of results and model validation are not purely epistemic. They are entangled with values, contexts of production and use, power relations, and pragmatic considerations. Situated Modelling extends a relational understanding of the world to scientific knowledge production and with that to modelling itself in order to enable a systematic interrogation of these choices and to research social-ecological transformations relationally. To make tangible the situatedness of simulation modelling, we build on existing practices and describe the situatedness of three distinct modelling approaches. We then suggest four guiding principles for Situated Modelling: 1. attending to the apparatus of knowledge production that is socially and materially embedded and produced by e.g. research infrastructures, power relations, and ways of thinking; 2. considering how agency is distributed between model, world, data, modeller in model construction; 3. creating heterogenous collectives which together occupy the formerly individualised subject position; and 4. using agonism as an epistemic virtue to retain and work with significant differentiations of social-ecological dynamics throughout the modelling process.Peer Reviewe
First Search for Heavy Neutral Leptons with IceCube DeepCore
Get PDFDie Beobachtung von Neutrino-Oszillationen hat gezeigt, dass Neutrinos eine von Null verschiedene Masse haben. Dieses Phänomen wird nicht durch das Standardmodell der Teilchenphysik beschrieben, aber eine mögliche Erklärung für dieses Dilemma ist die Existenz von schweren neutralen Leptonen in Form von rechtshändigen Neutrinos. Abhängig von ihrer Masse und Kopplung zu den Neutrinos des Standardmodells könnten diese Teilchen auch eine wichtige Rolle bei der Lösung weiterer unerklärter Beobachtungen wie Dunkler Materie und der Baryonenasymmetrie des Universums spielen. Diese Arbeit präsentiert die erste Suche nach schweren neutralen Leptonen mit dem IceCube Neutrino-Observatorium. Das standardmäßige Drei-Flavor-Neutrino-Modell wird erweitert, indem ein vierter Massenzustand im GeV-Bereich hinzugefügt wird und eine Mischung mit dem Tau-Neutrino durch den Parameter \ut4 erlaubt wird. Es werden drei Massenwerte für schwere neutrale Leptonen, , von \SI{0.3}{\gev}, \SI{0.6}{\gev} und \SI{1.0}{\gev} getestet, wobei zehn Jahre Daten aus den Jahren 2011 bis 2021 verwendet werden. Für keine der drei getesteten Massen wird ein signifikantes Signal von schweren neutralen Leptonen gemessen. Die resultierenden Einschränkungen für den Mischungsparameter sind \ut4 < 0.19\;(m_4 = \SI{0.3}{\gev}), \ut4 < 0.36\;(m_4 = \SI{0.6}{\gev}) und \ut4 < 0.40\;(m_4 = \SI{1.0}{\gev}) im \SI{90}{\percent} - Konfidenzniveau. Diese erste Analyse legt die grundlegende Basis für zukünftige Suchen nach schweren neutralen Leptonen in IceCube.The observation of neutrino oscillations has established that neutrinos have non-zero masses. This phenomenon is not explained by the standard model of particle physics, but one viable explanation to this dilemma is the existence of heavy neutral leptons in the form of right-handed neutrinos. Depending on their mass and coupling to standard model neutrinos, these particles could also play an important role in solving additional unexplained observations such as dark matter and the baryon asymmetry of the universe. This work presents the first search for heavy neutral leptons with the IceCube Neutrino Observatory. The standard three flavor neutrino model is extended by adding a fourth GeV-scale mass state and allowing mixing with the tau neutrino through the parameter \ut4. Three heavy neutral lepton mass values, , of \SI{0.3}{\gev}, \SI{0.6}{\gev}, and \SI{1.0}{\gev} are tested using ten years of data, collected between 2011 and 2021. No significant signal of heavy neutral leptons is observed for any of the tested masses. The resulting constraints for the mixing parameter are \ut4 < 0.19\;(m_4 = \SI{0.3}{\gev}), \ut4 < 0.36\;(m_4 = \SI{0.6}{\gev}), and \ut4 < 0.40\;(m_4 = \SI{1.0}{\gev}) at \SI{90}{\percent} confidence level. This first analysis lays the fundamental groundwork for future searches for heavy neutral leptons in IceCube
Transforming the Creative and Social Entrepreneurial Ecosystem: The Broker Roles of Rural Collaborative Workspaces
Get PDFCreative social enterprises are increasingly emerging in rural regions, motivated by a desire to take social responsibility through creative approaches. These enterprises integrate entrepreneurial activities with creative social attributes and are sometimes set in rural collaborative workspaces (CWSs) facilitating entrepreneurial activities. Under the frame of entrepreneurial ecosystems (EEs), we argue that CWSs can be seen as brokers, who (1) link resources as liaisons, (2) hold and pass resources as gatekeepers, (3) enhance resource flows as coordinators, and (4) reproduce experiences as representatives. Against this backdrop, this paper presents a case study of two creative social enterprises in a CWS with a cooperative structure in rural Upper Austria by analyzing entrepreneurial biographies about the demand and use of entrepreneurial resources. Through a comparison between before and after the emergence of the CWS, the findings suggest that the EE for creative and social entrepreneurship undergoes two different types of transformation, a radical and a gradual one. The brokerage process of the CWS enhances local resource networks’ transformation of EE and brings the transformation in terms of translocal resources and integral EE of enterprises in the CWS. Additionally, the CWS generates social impacts on the local community through social enterprises. This paper contributes to ecosystem literature by introducing an actor-centric perspective and giving new insights into social entrepreneurship and the transformative power of CWSs as brokers.This paper has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 955907, project CORAL (Exploring the impacts of collaborative workspaces in rural and peripheral areas in the EU).European Union’s Horizon 2020 research and innovation programmePeer Reviewe
Essays in behavioural economics
Get PDFIn der Wirtschaftswissenschaft sind Labor- und Online-Experimente immer beliebter geworden, da sie wertvolle Einblicke liefern, die traditionelle Methoden ergänzen. Diese Dissertation umfasst empirische Arbeiten in klassischen Laborumgebungen (Kapitel 1) und modernen Online-Umgebungen (Kapitel 2 und 3). Die Hauptthemen sind prosoziales Verhalten und Geschlechtsunterschiede in psychologischen Merkmalen und Verhaltensweisen – beides entscheidend für gesellschaftlichen Zusammenhalt und Gleichberechtigung. In Kapitel 1 untersuchen wir in einem Laborexperiment die Ausnutzung von moralischem Spielraum in einer sequenziellen Principal-Agent-Interaktion. Wir erforschen, ob Prinzipale versteckte Informationen als Vorwand für egoistisches Verhalten nutzen. In Kapitel 2 analysieren wir in einem Online-Experiment, wie sich Männer und Frauen in ihrem Durchhaltevermögen nach einem Misserfolg in einem Wettbewerbsumfeld unterscheiden, wobei die Art des Wettbewerbs (fair vs. unfair) variiert wird. In Kapitel 3 führen wir ein neues Maß für Geschlechtsidentität ein, basierend auf einem Online-Experiment. Wir zeigen, dass dieses Maß viele Verhaltensweisen besser erklärt als die biologische Geschlechtsvariable und existierende Geschlechtsidentitätsmaße. Diese Dissertation leistet vier Beiträge: Erstens erweitern wir die Literatur zum moralischen Spielraum auf eine Principal-Agent-Umgebung (Kapitel 1). Zweitens erweitern wir die Literatur zu Geschlechtsunterschieden in der Beharrlichkeit nach einem Misserfolg auf eine Online-Umgebung und unfaire Wettbewerbe (Kapitel 2). Drittens bieten wir ein neues und effektiveres Maß für die Geschlechtsidentität (Kapitel 3). Viertens zeigen wir, wie Methoden des maschinellen Lernens wie Lasso und Random Forest in Online-Experimenten genutzt werden können, um heterogene Effekte zu untersuchen (Kapitel 2).In economics the use of laboratory and online experiments has become more and more popu-
lar, often providing valuable insights that complement traditional observational and theoretical approaches. This dissertation entails empirical work in both classic laboratory setting (Chapter 1) and more modern online ones (Chapter 2 and 3). The main topics of this thesis are related to pivotal themes in nowadays society: pro-social behavior and gender differences in psychological traits and behaviours, two topics whose deeper understanding is crucial to foster societal cohesion and equal opportunities.
In Chapter 1, in a laboratory experiment we study moral wiggle room exploitation in a sequential principal-agent interaction. In particular, we study whether principals use hidden information as an excuse to behave more selfishly.
In Chapter 2, in an online experiment we study how men and women differ in their persistence after experiencing failure in a competitive environment, exogenously varying the nature of the competition; fair vs unfair.
In Chapter 3, based on an online experiment we propose a new measure of gender identity and show that it explains many behaviours better than the biological sex variable and better than gender identity measures already existing in the literature.
The contribution of this thesis is fourfold. First we extend the moral wiggle room literature to a principal-agent setting (Chapter 1), second we extend the literature of gender differences in persistence after failure to an online setting and to unfair competitions (Chapter 2), third we provide a new and more effective gender identity measure (Chapter 3), fourth we apply machine learning methods such as lasso and random forest estimation in an online experiment about gender differences, showcasing how these methods can be used to investigate heterogeneous effects in the context of experiments (Chapter 2)
Multisource Synthesized Inventory of CRitical Infrastructure and HUman-Impacted Areas in AlaSka (SIRIUS)
Get PDFThe Arctic region has undergone warming at a rate more than 3 times higher than the global average. This warming has led to the degradation of near-surface permafrost, resulting in decreased ground stability. This instability not only poses a primary hazard to Arctic infrastructure and human-impacted areas but can also lead to secondary ecological hazards from infrastructure failure associated with hazardous materials. This development underscores the need for a comprehensive inventory of critical infrastructure and human-impacted areas. The inventory should be linked to environmental data to assess their susceptibility to permafrost degradation as well as the ecological consequences that may arise from infrastructure failure. Here, we provide such an inventory for Alaska, a vast state covering approximately 1.7 × 106 km2, with a population of over 733 000 people and a history of industrial development on permafrost. Our Synthesized Inventory of CRitical Infrastructure and HUman-Impacted Areas in AlaSka (SIRIUS) integrates data from (i) the Sentinel-1/2-derived Arctic Coastal Human Impact dataset (SACHI); (ii) OpenStreetMap (OSM); (iii) the pan-Arctic Catchment Database (ARCADE); (iv) a dataset of permafrost extent, probability and mean annual ground temperatures; and (v) the Contaminated Sites Database and reports to create a unified new dataset of critical infrastructure and human-impacted areas as well as permafrost and watershed information for Alaska. The integration process included harmonizing spatial references, extents and geometries across all the datasets as well as incorporating a uniform usage type classification scheme for the infrastructure data. Additionally, we employed text-mining techniques to generate complementary geospatial data from textual reports on contaminated sites, including details on contaminants, cleanup duration and the affected media. The combination of SACHI and OSM enhanced the detail of the usage type classification for infrastructure from 5 to 13 categories, allowing the identification of elements critical to Arctic communities beyond industrial sites. Further, the new inventory integrates the high spatial detail of OSM with the unbiased infrastructure detection capability of SACHI, accurately representing 94 % of the polygonal infrastructure and 78 % of the linear infrastructure, respectively. The SIRIUS dataset is presented as a GeoPackage, enabling spatial analysis and queries of its components, either as a function of or in combination with one another. The dataset is available on Zenodo at https://doi.org/10.5281/zenodo.8311243 (Kaiser et al., 2023).Bundesministerium für Bildung und ForschungHumboldt-Universität zu BerlinHorizon 2020Peer Reviewe
Light-induced electron dynamics in and around metallic nanostructures
Get PDFGegenstand der Untersuchungen dieser Arbeit ist die analytische und numerische Studie der plasmonischen Eigenschaften vorhanden in Silbernanodrähten von verschiedener horizontaler Geometrie aufgrund verschiedener Modelle der optischen Antwort der
Leitungselektronen. Nach einer hierarchischen Anordnung von linearen Volumen-Materialmodellen, welche innerhalb der plasmonischen Literatur genutzt werden, untersuchen wir die Verwicklung von (nicht)lokaler und dispersiver Antwort mit
geometrischen Parametern von Monomeren und Dimeren. Unsere analytischen Studien fokussieren sich auf einzelne zylindrische Drähte, wobei wir das Auftreten von Radius-abhängiger Dämpfung in lokalisierten Oberflächenplasmonen nachweisen, ähnlich dem
Konzept der begrenzten mittleren freien Weglänge diskutiert von Kreibig und Mitarbeitern. Weiterhin wird ein Streuproblem mit transversaler Nichtlokalität und "No-slip"- Randbedingung gelöst, gefolgt von einer Diskussion einer Randbedingung, welche
zwischen “No-Slip”- und “Slip”-Bedinung interpoliert. Aus numerischer Sicht wird die Streuung an abgerundeten und gleichseitigen dreieckigen und Bowtie-Drähten behandelt mit Fokus auf einer vollanalytischen Beschreibung der Eckenrundung mittels Bézier-
Kurven. Dies enthüllt den Krümmungsradius als neuen geometrischen Parameter. Das Variieren der Lückenbreite und Eckenrundung führt zu Verstärkungsfaktoren, welche relevant für oberflächenverstärkte Raman-Streuung einzelner Moleküle sind, in ausgezeichneten räumlichen Bereichen abhängig von der Art der Resonanz. Innerhalb der
Extinktionsspektren von dreieckigen und Bowtie-Drähten erscheint eine Sequenz von nichtlokalen Maxima. Diese Sequenz ist am sensitivsten in Bezug auf die Änderung der Krümmung. Die Identifikation der (Hybrid-)Resonanzen basiert auf simulierten Ladungsdichteverteilungen.Subject of this thesis is the analytical and numerical study of the plasmonic properties present in silver nanowires of different horizontal geometries due to different models of optical response of conduction electrons. Following a hierarchical arrangement of
linear bulk material models, used throughout the plasmonic literature, we investigate the intertwining of (non)local and dispersive response with geometrical parameters of monomers and dimers. Our analytical studies focus on single cylindrical wires, revealing the occurrence of radius-dependent damping of localized surface plasmons similar to the concept of limited-mean-free-path discussed by Kreibig and coworkers. Further, a scattering problem with transverse nonlocality and s no-slip condition is solved followed by a discussion of a boundary condition interpolating between the slip and no-slip conditions. On a numerical level, the scattering by rounded and equilateral triangular and bowtie nanowires is treated based on
a full analytical description of the corner rounding via Bézier curves revealing the radius of curvature as a new geometrical degree of freedom. Tuning of gap size and corner rounding reveals enhancement factors relevant for surface-enhanced Raman scattering of single molecules in distinguished spatial domains dependent on the type of resonance. Within
the extinction spectra a nonlocal peak sequence emerges. This sequence is most sensitive to curvature variations and arises in the triangular monomer and bowtie dimer. The identification of (hybrid) resonances is based on charge density simulations
Correct decision for the wrong reasons?
Get PDFThe article processing charge was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – 491192747 and the Open Access Publication Fund of Humboldt-Universität zu Berlin.Data comparison problems are used in teaching and science education research that focuses on students’ ability to compare datasets and their conceptual understanding of measurement uncertainties. However, the evaluation of students’ decisions in these problems can pose a problem: e.g., students making a correct decision for the wrong reasons. Three previous studies, that share the same context and data comparison problem but where participants had increasing conceptual knowledge of measurement uncertainties, are revisited. The comparison shows a troublesome result: increasing conceptual knowledge does not lead to better decision making in the data comparison problem. In this research, we have looked into this apparent discrepancy by comparing and reanalyzing the data from these three studies. We have analyzed students’ justifications by coding them based on the compared quantity and the deciding criterion, giving a highly detailed insight into what they do when comparing the datasets. The results show clear differences in the quality of the justifications across the studies and by combining the results with the decisions, we could successfully identify four cases of correct and incorrect decisions for right or wrong reasons. This analysis showed a high prevalence of correct decisions for wrong reasons in two of the studies, resolving the discrepancy in the initial comparison of these studies. The implication of our analysis is that simply asking students to make a decision in data comparison problems is not a suitable probe to gauge their ability to compare datasets or their conceptual understanding of measurement uncertainties and a probe like this should always be complemented by an analysis of the justification.Peer Reviewe
Matters of Perspective at the Humboldt Forum
Get PDFIn this exhibition review I discuss the curatorial choices employed in the installation Matters of Perspective in the Humboldt Forum’s Ethnological Museum, Berlin. I examine the exhibition’s key framing elements, analyze the sub-installation entitled Das Deutsche in mir ist indirekt, and conclude with a discussion of the adjacent artwork Township Wall, interpreting its role in shaping perceptions about the African collections. I argue that Matters of Perspective is strident in revealing aspects of the German colonial past pertinent to the encounter with ethnological collections at a time of roiling public debate. It boldly introduces historical issues of race, difference, and German colonial legacies, and does especially well at profiling socialist histories of transnational solidarity during the Cold War. Yet, overall, the exhibition deals in a language of contrition that, while familiar in a German cultural context, from other vantage points may appear to some viewers as more self-congratulatory than critical. In other words, the exhibition’s framing of perspectives is rather out of focus with the substantive matters of power, history, and structural racism at stake when addressing colonial legacies in a museum setting such as this one.In dieser Ausstellungsrezension diskutiere ich die kuratorischen Entscheidungen, die im Rahmen der Installation Ansichtssache(n) im Ethnologischen Museum des Humboldt Forums in Berlin getroffen wurden. Ich untersuche die Kernelemente der Ausstellung, analysiere die Teilausstellung Das Deutsche in mir ist indirekt und schließe mit einer Diskussion des angrenzenden Kunstwerks Township Wall, wobei ich die Rolle dieses Kunstwerks in Bezug auf die Wahrnehmung der afrikanischen Sammlungen interpretiere. Ich argumentiere, dass Ansichtssache(n) Aspekte der deutschen kolonialen Vergangenheit aufzeigt, die für die Auseinandersetzung mit ethnologischen Sammlungen in einer Zeit hitziger öffentlicher Debatten relevant sind. Die Ausstellung behandelt auf mutige Weise historische Themen wie race, Differenz und deutsches Kolonialerbe und stellt besonders gut die sozialistische Geschichte der transnationalen Solidarität während des Kalten Krieges dar. Doch insgesamt bedient sich die Ausstellung einer Sprache der Reue, die in der deutschen Kulturlandschaft zwar nicht unbekannt ist, die aber aus manchen Blickwinkeln eher selbstgefällig als kritisch erscheint. Mit anderen Worten sind die Perspektiven der Ausstellung nicht auf die wesentlichen Fragen von Macht, Geschichte und strukturellem Rassismus gerichtet, um die es bei der Auseinandersetzung mit kolonialem Erbe in einem Museum wie dem vorliegenden eigentlich gehen sollte.Peer Reviewe
A Lexical Phonology Approach to Russian–German Consonantal Interference
Get PDFDer Spracherwerb umfasst einen vielschichtigen Prozess, der die Beherrschung verschiedener linguistischer Elemente, insbesondere der Phonologie, beinhaltet. Der Erwerb einer Zweitsprache (L2) stellt häufig eine Herausforderung bei der Assimilation der phonologischen Struktur der Zielsprache dar, die von der Phonologie der Muttersprache (L1) beeinflusst wird. Das Phänomen der phonologischen Interferenz, bei dem die phonologischen Regeln der L1 den Erwerb der L2 beeinflussen, hat das Interesse von Forschern auf dem Gebiet des Zweitspracherwerbs geweckt. Diese Masterarbeit untersucht die phonologische Interferenz zwischen Russisch und Deutsch mit einem besonderen Schwerpunkt auf den Mechanismen der Regelanwendung und -ordnung. Hierbei werden nicht nur allgemeine Stimmhaftigkeitsalternationen wie Auslautsverhärtung und regressive Assimilation berücksichtigt, sondern auch Regeln, die nur im phonologischen System des Russischen als L1 vorkommen. Darüber hinaus zielt die Untersuchung darauf ab, die Erkenntnisse von Rubach (1984) über die Rolle der Regelzuweisung zu den Komponenten der lexikalischen Phonologie bei der phonologischen Interferenz zu festigen und zu erweitern, indem die in der Literatur gefundenen Fälle des Transfers vom Russischen ins Deutsche untersucht werden. Die angestrebten Ergebnisse dieser Masterarbeit umfassen ein umfangreiches Verständnis der Zuweisung russischer phonologischer Regeln innerhalb der lexikalischen Phonologie. Durch die Untersuchung der Regelordnung und -anwendung in den Phonologien sowohl von L1 als auch von L2 strebt diese Studie einen Beitrag zu der Entwicklung einer einheitlichen Theorie der phonologischen Interferenz im Zweitspracherwerb an.Language acquisition involves a complex process encompassing the mastery of various linguistic elements, particularly phonology. Acquiring a second language (L2) often presents challenges in assimilating the target language's phonological structure, influenced by the native language's (L1) phonology. The phenomenon of phonological interference, wherein the phonological rules of the L1 impact the acquisition of the L2, has been a subject of interest for researchers in the field of second language acquisition. This master's thesis investigates phonological interference between Russian and German, with a particular emphasis on the mechanisms of rule application and ordering. It aims to elucidate the role of rule ordering in Russian to German phonological interference, taking into account rules related to voice alternations, such as final devoicing and regressive devoicing, while also addressing rules unique to the phonology of Russian as the L1. Additionally, the investigation aims to solidify and extend the findings of Rubach (1984) on the role of rule allocation to Lexical Phonology components in phonological interference, by examining cases of Russian to German transfer found in the literature. Expected outcomes from this master's thesis include a deep understanding of Russian phonological rule allocation within the framework of Lexical Phonology. By exploring rule ordering and application in both L1 and L2 phonologies, this study aims to contribute to the development of a unified theory of phonological interference in second language acquisition