13979 research outputs found
Sort by
Sprachliche Formierungen von Technologierisiken und ihre Folgen
Get PDFFrüherkennung und Einschätzung des Umgangs mit Technologierisiken gehören zum Kerngeschäft der Technikfolgenabschätzung (TA). Die kommunikative Behandlung von Technologierisiken stellt einen Teil der gesellschaftlichen Umgangsweisen mit Risiken dar, die ihrerseits Folgen für die Entwicklung von neuen Technologien in der Gesellschaft hat. Im Zuge der Konfrontation der TA mit NEST (new and emerging science and technologies) und ihren unbekannten Zukünften rückt die Bedeutung von Debatten-Assessments in den Blick der TA. Hierfür sind besonders Analytiken der sozial- und sprachwissenschaftlichen Diskursforschung gefragt, die sowohl die sprachliche Thematisierungen von Technologien als Risiken sowie deren Folgen als Diskursrisiken analysieren können. Der Schwerpunkt zeigt, was unterschiedliche soziologische und sprachwissenschaftliche Diskursforschungen erkennen und wie ihre Einsichten die TA als Folgenforschung bereichern können
Parahydrogen-induced polarization enables the single-scan NMR detection of a 236 kDa biopolymer at nanomolar concentrations
Get PDFNuclear magnetic resonance (NMR) experiments utilizing parahydrogen-induced polarization (PHIP) were performed to elucidate the PHIP activity of the synthetic 236 kDa biopolymer poly-γ-(4-propargyloxy)-benzyl-L-glutamate) (PPOBLG). The homopolypeptide was successfully hyperpolarized and the enhanced signals were detected in 11.7 T solution NMR as a function of the PPOBLG concentration. The hydrogenation with parahydrogen caused signal enhancements of 800 and more for the vinyl protons of the side chain at low substrate concentration. As a result of this high enhancement factor, even at 13 nM of PPOBLG, a single scan ¹H-NMR detection of the hyperpolarized protons was possible, owing to the combination of hyperpolarization and density of PHIP active sites
Simulated biomechanical performance of morphologically disparate ant mandibles under bite loading
No full textInsects evolved various modifications to their mouthparts, allowing for a broad exploration of feeding modes. In ants, workers perform non-reproductive tasks like excavation, food processing, and juvenile care, relying heavily on their mandibles. Given the importance of biting for ant workers and the significant mandible morphological diversity across species, it is essential to understand how mandible shape influences its mechanical responses to bite loading. We employed Finite Element Analysis to simulate biting scenarios on mandible volumetric models from 25 ant species classified in different feeding habits. We hypothesize that mandibles of predatory ants, especially trap-jaw ants, would perform better than mandibles of omnivorous species due to their necessity to subdue living prey. We defined simulations to allow only variation in mandible morphology between specimens. Our results demonstrated interspecific differences in mandible mechanical responses to biting loading. However, we found no evident differences in biting performance between the predatory and the remaining ants, and trap-jaw mandibles did not show lower stress levels than other mandibles under bite loading. These results suggest that ant feeding habit is not a robust predictor of mandible biting performance, a possible consequence of mandibles being employed as versatile tools to perform several tasks
Mutation induced infection waves in diseases like COVID-19
Get PDFAfter more than 6 million deaths worldwide, the ongoing vaccination to conquer the COVID-19 disease is now competing with the emergence of increasingly contagious mutations, repeatedly supplanting earlier strains. Following the near-absence of historical examples of the long-time evolution of infectious diseases under similar circumstances, models are crucial to exemplify possible scenarios. Accordingly, in the present work we systematically generalize the popular susceptible-infected-recovered model to account for mutations leading to repeatedly occurring new strains, which we coarse grain based on tools from statistical mechanics to derive a model predicting the most likely outcomes. The model predicts that mutations can induce a super-exponential growth of infection numbers at early times, which self-amplify to giant infection waves which are caused by a positive feedback loop between infection numbers and mutations and lead to a simultaneous infection of the majority of the population. At later stages—if vaccination progresses too slowly—mutations can interrupt an ongoing decrease of infection numbers and can cause infection revivals which occur as single waves or even as whole wave trains featuring alternative periods of decreasing and increasing infection numbers. This panorama of possible mutation-induced scenarios should be tested in more detailed models to explore their concrete significance for specific infectious diseases. Further, our results might be useful for discussions regarding the importance of a release of vaccine-patents to reduce the risk of mutation-induced infection revivals but also to coordinate the release of measures following a downwards trend of infection numbers
Contrasting packing modes for tubular assemblies in chlorosomes
Get PDFThe largest light-harvesting antenna in nature, the chlorosome, is a heterogeneous helical BChl self-assembly that has evolved in green bacteria to harvest light for performing photosynthesis in low-light environments. Guided by NMR chemical shifts and distance constraints for Chlorobaculum tepidum wild-type chlorosomes, the two contrasting packing modes for syn-anti parallel stacks of BChl c to form polar 2D arrays, with dipole moments adding up, are explored. Layered assemblies were optimized using local orbital density functional and plane wave pseudopotential methods. The packing mode with the lowest energy contains syn-anti and anti-syn H-bonding between stacks. It can accommodate R and S epimers, and side chain variability. For this packing, a match with the available EM data on the subunit axial repeat and optical data is obtained with multiple concentric cylinders for a rolling vector with the stacks running at an angle of 21° to the cylinder axis and with the BChl dipole moments running at an angle ß ∼ 55° to the tube axis, in accordance with optical data. A packing mode involving alternating syn and anti parallel stacks that is at variance with EM appears higher in energy. A weak cross-peak at -6 ppm in the MAS NMR with 50 kHz spinning, assigned to C-18¹, matches the shift of antiparallel dimers, which possibly reflects a minor impurity-type fraction in the self-assembled BChl c
Utility-based performance evaluation of biometric sample quality measures
No full textThe quality score of a biometric sample is intended to predict the sample’s degree of utility for biometric recognition. Different authors proposed different definitions for utility. A harmonized definition of utility would be useful to facilitate the comparison of biometric sample quality assessment algorithms. In this article, we compare different definitions of utility and apply them to both face image and fingerprint image data sets containing multiple samples per biometric instance and covering a wide range of potential quality issues. The results differ only slightly. We show that discarding samples with low utility scores results in rapidly declining false non-match rates. The obtained utility scores can be used as target labels for training biometric sample quality assessment algorithms and as baseline when summarizing utility-prediction performance in a single plot or even in a single figure of merit
Radiation-induced DNA double-strand breaks in cortisol exposed fibroblasts as quantified with the novel foci-integrated damage complexity score (FIDCS)
Get PDFWithout the protective shielding of Earth’s atmosphere, astronauts face higher doses of ionizing radiation in space, causing serious health concerns. Highly charged and high energy (HZE) particles are particularly effective in causing complex and difficult-to-repair DNA double-strand breaks compared to low linear energy transfer. Additionally, chronic cortisol exposure during spaceflight raises further concerns, although its specific impact on DNA damage and repair remains unknown. This study explorers the effect of different radiation qualities (photons, protons, carbon, and iron ions) on the DNA damage and repair of cortisol-conditioned primary human dermal fibroblasts. Besides, we introduce a new measure, the Foci-Integrated Damage Complexity Score (FIDCS), to assess DNA damage complexity by analyzing focus area and fluorescent intensity. Our results show that the FIDCS captured the DNA damage induced by different radiation qualities better than counting the number of foci, as traditionally done. Besides, using this measure, we were able to identify differences in DNA damage between cortisol-exposed cells and controls. This suggests that, besides measuring the total number of foci, considering the complexity of the DNA damage by means of the FIDCS can provide additional and, in our case, improved information when comparing different radiation qualities
The discovery of an overseen pygmy backswimmer in Europe (Heteroptera, Nepomorpha, Pleidae)
Get PDFThe Pleidae, or pygmy backswimmers, is a family of aquatic bugs (Hemiptera, Heteroptera, Nepomorpha) containing four genera. Here, we describe Plea cryptica sp. nov. and redescribe its sister species, Plea minutissima Leach, 1817. Whereas the morphological distinction of these closely related species is only possible for males, molecular data clearly separate them. As part of our taxonomic study, we provide comprehensive molecular data including more than 200 DNA barcodes from all over Europe, complete nuclear ribosomal DNA, full mitochondrial genome data, and 3D scans for both species. Furthermore, the same molecular markers are also presented for Neoplea striola (Fieber, 1844). We used Maximum Likelihood (ML) analyses to reconstruct the phylogeny of the Pleidae and Notonectoidea based on available mitogenomic data. Our study represents a successful implementation of the proposed concept of taxonomics, using data from high-throughput sequencing technologies for integrative taxonomic studies, and allowing high confidence for both biodiversity and ecological research
Implementation quality of cooperative learning and teacher beliefs — a mixed methods study
Get PDFCooperative learning (CL) refers to teaching methods in which students work in small groups to help one another learn and improve their learning outcomes. Often CL is described by five basic elements: (1) positive interdependence, (2) individual accountability, (3) promotive interaction, (4) social skills and (5) group processing. The positive effects of CL have been extensively documented. The quality of implementation, mostly determined by application of the five basic elements of CL, has been shown to be significantly related to the effectiveness of the methods. However, due to the complex demands that designing CL sequences places on teachers, the question of how and why they implement CL methods is not trivial. The present study used an explanatory mixed methods design with sequential phases (quantitative–qualitative) to investigate the implementation of CL in school practice. A survey, structured interviews with teachers and classroom observations rated on an observation scale including indicators of the basic elements of CL were used to gather data in a total of 49 German classrooms. Results show that the implementation quality of CL lessons was rather low. Only 7% of the observed teachers implemented the basic elements. Even group goals and individual accountability, the two most important elements of CL, were implemented in only 17% of the lessons observed. Survey results indicated that implementation quality is related to teachers’ evaluation of CL with regard to its appropriateness for different learning goals (r = .40*) and diverse students (r = .36*). Qualitative analysis of the teacher interviews analysed by thematic coding showed differences between teachers with high and low implementation quality regarding their beliefs. Teachers with high implementation quality see more value in social learning processes and feel more responsible for the success of CL. The results show a theory–practice gap and point to the relevance of beliefs for CL implementation
Retrieval methods for legal question answering in German
Get PDFThis thesis investigates the effectiveness of various Information Retrieval (IR) Systems in addressing legal questions formulated in layman’s terms within the German legal domain. The study utilizes the GerLayQA[3] dataset, comprising legal questions sourced from
the popular online platform “Frag-einen-Anwalt.de” aiming to evaluate the capability of IR systems to retrieve relevant paragraphs from German legal texts in response to these queries. The research employs a diverse range of retrieval methods, including baseline approaches such as TF-IDF and BM25 and more advanced techniques based on state-of-the-art language models. A significant focus is placed on comparing the performance of pre-trained and fine-tuned Bi-Encoder models and highlighting the impact of domain-specific training on retrieval accuracy. Furthermore, the study explores the
potential of a Retrieve-and-Re-Rank pipeline combining the efficiency of Bi-Encoders with the precision of Cross-Encoders. This approach is evaluated against single-stage retrieval methods to assess its viability in the legal domain. This work makes a novel contribution by developing and evaluating a Majority Vote IR model, which aggregates results from multiple retrieval methods through a majority voting mechanism and thereby tries to minimize the effect of any single IR system weakness. This ensemble approach is
compared against individual models to determine its effectiveness in improving retrieval performance. The performance of these systems is rigorously evaluated using standard information retrieval metrics, including the Precision@k, Recall@k, F1@k-Score, and the
Normalized Discounted Cumulative Gain (NDCG). The results are critically analyzed to identify the strengths and limitations of each approach within the context of German Legal Information Retrieval. This research aims to contribute to the growing field of legal
AI by providing insights into the applicability and challenges of various IR techniques for processing German layman legal queries. The findings have implications for developing more accessible and efficient legal information systems, potentially closing the gap between complex legal language and public understanding