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The business problem of having inefficient processes, imprecise process analyses, and simulations as well as non-transparent artificial neuronal network models can be overcome by an easy-to-use modeling concept. With the aim of developing a flexible and efficient approach to modeling, simulating, and optimizing processes, this paper proposes a flexible Concept of Neuronal Modeling (CoNM). The modeling concept, which is described by the modeling language designed and its mathematical formulation and is connected to a technical substantiation, is based on a collection of novel sub-artifacts. As these have been implemented as a computational model, the set of CoNM tools carries out novel kinds of Neuronal Process Modeling (NPM), Neuronal Process Simulations (NPS), and Neuronal Process Optimizations (NPO). The efficacy of the designed artifacts was demonstrated rigorously by means of six experiments and a simulator of real industrial production processes.
This paper reads ‘The Detainee’s Tale as told to Ali Smith’ (2016) as an exemplary demonstration of the work of world literature. Smith’s story articulates an ethics of reading that is grounded in the recipient’s openness to the singular, unpredictable, and unverifiable text of the other. More specifically, Smith’s account enables the very event that it painstakingly stages: the encounter with alterity and newness, which is both the theme of the narrative and the effect of the text on the reader. At the same time, however, the text urges to move from an ethics of literature understood as the responsible reception of the other by an individual reader to a more explicitly convivial and political ethics of commitment beyond the scene of reading.
Promoting the decarbonization of economic activity through climate policies raises many questions. From a macroeconomic perspective, it is important to understand how these policies perform under uncertainty, how they affect short-run dynamics and to what extent they have distributional effects. In addition, uncertainties directly associated with climate policies, such as uncertainty about the carbon budget or emission intensities, become relevant aspects. We study the implications of emission reduction schemes within a Two-Agent New-Keynesian (TANK) model. This quantitative exercise, based on data for the German economy, provides various insights. In the light of frictions and fluctuations, compared to other instruments, a carbon price (i.e. tax) is associated with lower volatility in output and consumption. In terms of aggregate welfare, price instruments are found to be preferable. Conditional on the distribution of revenues from climate policies, quantity instruments can exert regressive effects, posing a larger economic loss on wealth-poor households, whereas price instruments are moderately progressive. Finally, we find that unexpected changes in climate policies can induce substantial aggregate adjustments. With uncertainty about the carbon budget, the costs of adjustment are larger under quantity instruments.
Deoxyribonucleic acid (DNA) nanostructures enable the attachment of functional molecules to nearly any unique location on their underlying structure. Due to their single-base-pair structural resolution, several ligands can be spatially arranged and closely controlled according to the geometry of their desired target, resulting in optimized binding and/or signaling interactions.
This dissertation covers three main projects. All of them use variations of functionalized DNA nanostructures that act as platform for oligovalent presentation of ligands. The purpose of this work was to evaluate the ability of DNA nanostructures to precisely display different types of functional molecules and to consequently enhance their efficacy according to the concept of multivalency. Moreover, functionalized DNA structures were examined for their suitability in functional screening assays. The developed DNA-based compound ligands were used to target structures in different biological systems.
One part of this dissertation attempted to bind pathogens with small modified DNA nanostructures. Pathogens like viruses and bacteria are known for their multivalent attachment to host cells membranes. By blocking their receptors for recognition and/or fusion with their targeted host in an oligovalent manner, the objective was to impede their ability to adhere to and invade cells. For influenza A, only enhanced binding of oligovalent peptide-DNA constructs compared to the monovalent peptide could be observed, whereas in the case of respiratory syncytial virus (RSV), binding as well as blocking of the target receptors led to an increased inhibition of infection in vitro.
In the final part, the ability of chimeric DNA-peptide constructs to bind to and activate signaling receptors on the surface of cells was investigated. Specific binding of DNA trimers, conjugated with up to three peptides, to EphA2 receptor expressing cells was evaluated in flow cytometry experiments. Subsequently, their ability to activate these receptors via phosphorylation was assessed. EphA2 phosphorylation was significantly increased by DNA trimers carrying three peptides compared to monovalent peptide. As a result of activation, cells underwent characteristic morphological changes, where they "round up" and retract their periphery.
The results obtained in this work comprehensively prove the capability of DNA nanostructures to serve as stable, biocompatible, controllable platforms for the oligovalent presentation of functional ligands. Functionalized DNA nanostructures were used to enhance biological effects and as tool for functional screening of bio-activity. This work demonstrates that modified DNA structures have the potential to improve drug development and to unravel the activation of signaling pathways.
While W.E.B. Du Bois’s first novel, The Quest of the Silver Fleece (1911), is set squarely in the USA, his second work of fiction, Dark Princess: A Romance (1928), abandons this national framework, depicting the treatment of African Americans in the USA as embedded into an international system of economic exploitation based on racial categories. Ultimately, the political visions offered in the novels differ starkly, but both employ a Western literary canon – so-called ‘classics’ from Greek, German, English, French, and US American literature. With this, Du Bois attempts to create a new space for African Americans in the world (literature) of the 20th century. Weary of the traditions of this ‘world literature’, the novels complicate and begin to decenter the canon that they draw on. This reading traces what I interpret as subtle signs of frustration over the limits set by the literature that underlies Dark Princess, while its predecessor had been more optimistic in its appropriation of Eurocentric fiction for its propagandist aims.
Massive Open Online Courses (MOOCs) open up new opportunities to learn a wide variety of skills online and are thus well suited for individual education, especially where proffcient teachers are not available locally. At the same time, modern society is undergoing a digital transformation, requiring the training of large numbers of current and future employees. Abstract thinking, logical reasoning, and the need to formulate instructions for computers are becoming increasingly relevant. A holistic way to train these skills is to learn how to program. Programming, in addition to being a mental discipline, is also considered a craft, and practical training is required to achieve mastery. In order to effectively convey programming skills in MOOCs, practical exercises are incorporated into the course curriculum to offer students the necessary hands-on experience to reach an in-depth understanding of the programming concepts presented. Our preliminary analysis showed that while being an integral and rewarding part of courses, practical exercises bear the risk of overburdening students who are struggling with conceptual misunderstandings and unknown syntax. In this thesis, we develop, implement, and evaluate different interventions with the aim to improve the learning experience, sustainability, and success of online programming courses. Data from four programming MOOCs, with a total of over 60,000 participants, are employed to determine criteria for practical programming exercises best suited for a given audience.
Based on over five million executions and scoring runs from students' task submissions, we deduce exercise difficulties, students' patterns in approaching the exercises, and potential flaws in exercise descriptions as well as preparatory videos. The primary issue in online learning is that students face a social gap caused by their isolated physical situation. Each individual student usually learns alone in front of a computer and suffers from the absence of a pre-determined time structure as provided in traditional school classes. Furthermore, online learning usually presses students into a one-size-fits-all curriculum, which presents the same content to all students, regardless of their individual needs and learning styles. Any means of a personalization of content or individual feedback regarding problems they encounter are mostly ruled out by the discrepancy between the number of learners and the number of instructors. This results in a high demand for self-motivation and determination of MOOC participants. Social distance exists between individual students as well as between students and course instructors. It decreases engagement and poses a threat to learning success. Within this research, we approach the identified issues within MOOCs and suggest scalable technical solutions, improving social interaction and balancing content difficulty.
Our contributions include situational interventions, approaches for personalizing educational content as well as concepts for fostering collaborative problem-solving. With these approaches, we reduce counterproductive struggles and create a universal improvement for future programming MOOCs. We evaluate our approaches and methods in detail to improve programming courses for students as well as instructors and to advance the state of knowledge in online education.
Data gathered from our experiments show that receiving peer feedback on one's programming problems improves overall course scores by up to 17%. Merely the act of phrasing a question about one's problem improved overall scores by about 14%. The rate of students reaching out for help was significantly improved by situational just-in-time interventions. Request for Comment interventions increased the share of students asking for help by up to 158%. Data from our four MOOCs further provide detailed insight into the learning behavior of students. We outline additional significant findings with regard to student behavior and demographic factors. Our approaches, the technical infrastructure, the numerous educational resources developed, and the data collected provide a solid foundation for future research.
Paths Are Made by Walking
(2021)
Introduction
(2021)
This edited volume examines entanglements and disentanglements between Africa and East Germany during and after the Cold War from a global history perspective. Extending the view beyond political elites, it asks for the negotiated and plural character of socialism in these encounters and sheds light on migration, media, development, and solidarity through personal and institutional agency. With its distinctive focus on moorings and unmoorings, the volume shows how the encounters, albeit often brief, significantly influenced both African and East German histories.