Qucosa - Publikationsserver der Universität Leipzig
Not a member yet
16020 research outputs found
Sort by
125Te NMR study of the bulk of topological insulators Bi2Te3 and Sb2Te3
No full textThe narrow band gap semiconductors Bi2Te3 and Sb2Te3 are well known for their room temperature thermoelectric performance. Recently, they were shown to serve as model systems of three-dimensional topological insulators with a bulk band gap and very robust, spin-resolved surface states due to a special band inversion in their periodic bulk. Evidently, it is of interest to investigate the special surface states with a local probe like nuclear magnetic resonance (NMR). However, especially the bulk NMR of these materials shows peculiar and rather unexpected phenomena, e. g., a magnetic field induced deformation of the local charge symmetry and excessive line broadening due to a special internuclear coupling. Here we report a comprehensive account of the room temperature NMR properties of the spin-1/2 nucleus 125Te of single crystalline Bi2Te3 and Sb2Te3. This includes a very unusual spin-lattice relaxation that seems not to be reflected in the NMR shift, as well as an exchange enhanced NMR line broadening
Robotic Competitions to Design Future Transport Systems: The Case of JRC AUTOTRAC 2020
No full textVehicle automation and connectivity bring new opportunities for safe and sustainable mobility in urban and highway networks.
Such opportunities are however not directly associated with traffic flow improvements. Research on exploitation of connected
and automated vehicles (CAVs) toward a more efficient traffic currently remains at a theoretical level, and/or based
on simulation models with limited reliability. Furthermore, testing CAVs in the real world is still costly and very challenging
from an implementation perspective. A possible alternative is to use automated robots. By designing and testing both the
low- and the high-level controllers of CAVs, it is indeed possible to reach a better understanding of the challenges that future
vehicles will need to face. Robotic applications can effectively test these challenges within a wide variety of research
communities—for example, via robotic competitions. Along this direction, the Joint Research Centre has organized the first
European robotic traffic competition for automated miniature vehicles. Each team participated with four robots and was
judged based on a set of indicators that assess the collective behaviors of the vehicles. Results show the suitability of the
methodology with different teams proposing completely different approaches to deal with the challenge and thus achieving
different results. Future competitions may further raise awareness about the possibility of using CAVs to improve traffic and
to engage with a broader community to design systems that are really capable of achieving this goal
Review: Yasna Bozhkova. Between Worlds: Mina Loy’s Aesthetic Itineraries
No full textYasna Bozhkova’s exciting new study of the modernist author, artist, and entrepreneur
Mina Loy (1882–1966) participates in a promising new phase in Loy studies.
After an initial period of predominantly feminist rediscovery in the 1980s and 1990s,
scholarly interest broadened in the new millennium, with critics seeking to restore
Loy’s rightful place in the modernist canon and come to terms with her diverse,
shifting aesthetics and their challenge to bourgeois sensibilities. This revival of interest
has been facilitated by significant editorial efforts: as unpublished texts
became accessible, new avenues of research emerged. Seeking to assess the aesthetic
trajectory of a writer and artist who was a satellite to all the modernist greats while
managing to remain committed to an orbit entirely her own, Between Worlds is a
timely and enriching contribution to the field in a year that also saw the publication
of a new biography (Mary Ann Caws) and awaits an exhibition of Loy’s visual artworks
at Bowdoin College of Art in 2023 – the first since 1959
A guide to adhesion GPCR research
No full textAdhesion G protein-coupled receptors (aGPCRs) are a class of structurally and functionally highly intriguing cell surface receptors with essential functions in health and disease. Thus, they display a vastly unexploited pharmacological potential. Our current understanding of the physiological functions and signaling mechanisms of aGPCRs form the basis for elucidating further molecular aspects. Combining these with novel tools and methodologies from different fields tailored for studying these unusual receptors yields a powerful potential for pushing aGPCR research from singular approaches toward building up an in-depth knowledge that will facilitate its translation to applied science. In this review, we summarize the state-of-the-art knowledge on aGPCRs in respect to structure-function relations, physiology, and clinical aspects, as well as the latest advances in the field. We highlight the upcoming most pressing topics in aGPCR research and identify strategies to tackle them. Furthermore, we discuss approaches how to promote, stimulate, and translate research on aGPCRs 'from bench to bedside' in the future
Evaluation of the Blood Neutrophil-to-Lymphocyte Ratio (NLR) as a Diagnostic and Prognostic Biomarker in Dogs with Chronic Enteropathy and Dogs with Portosystemic Shunt
No full textDie Dissertation befasst sich mit der Neutrophil-zu-Lymphozyten Ratio (NLR) als diagnostischer und prognostischer Marker bei Hunden mit chronsicher Darmerkrankung (IBD) und bei Hunden mit protosystemischem Shunt (PSS). Es handelt sich um eine kummulative Arbeit, welche zwei Publikationen zu den genannten Themen beinhaltet und diskutiert. In der Literaturrecherche wird auf die beiden untersuchten Erkrankungen, sowie auf Leukozyten und die NLR als Marker für chronsiche und akute Entzündungen (auch vergleichend mit Erkenntnissen aus der Humanmedizin) eingegangen. Die beiden Publikationen beschreiben zwei retrospektive Studien, die den Nutzen der NLR als Marker bei Hunden mit IBD und PSS untersuchen. Zusammenfassend kann man sagen dass die NLR bei Hunden mit chronischer Darmerkrankung vielversprechenden Nutzen zeigt, beispielsweise zur frühzeitigen Unterklassifizerung der Erkrankung. Für Hunde mit Portosystemischem Shunt zeigte die NLR nur begrenzten diagnostischen Nutzen, jedoch lässt sich ggf. eine Aussage über die Anzahl der notwendigen chirurgischen Eingriffe zum Verschluss des Shunt-Gefäßes ableiten.:1. Introduction
2. Review of Literature
2.1 Chronic Enteropathies in Dogs
2.1.1 Food-responsive Enterpathy (FRE)
2.1.2 Antibiotic-responsive Enteropathy (ARE)
2.1.3 Idiopathic Inflammatory Bowel Disease
2.1.4 Protein-Losing Enteropathy
2.2 Portosystemic Shunt in Dogs
2.2.1 Classification and Pathophysiology
2.2.2 Clinical Presentation
2.2.3 Clinical Diagnostics
2.2.4 Medical Treatment
2.2.5 Surgical Treatment
2.3 Diagnostic and Prognostic Biomarkers ans Scoring Systems in Dogs with Chronic Enteropathies
2.3.1 CIBDAI and CCECAI Scoring Systems
2.3.2 Fecal α1-Proteinase-Inhibitor, Calprotectin, and S100A12 Concentrations
2.3.3 Serum Albumin, C-Reactive Protein, Cobalamin, ans Folic Acid Concentrations
2.4 Diagnostic and Prognostic Biomarkers in Dogs with PSS
2.5 Leukogram - Morphology and Functions of Leukocytes
2.5.1 Neutrophilic Granulocytes
2.5.2 Eosinophilic Granulocytes
2.5.3 Basophilic Granulocytes
2.5.4 Lymphocytes
2.5.5 Monocytes
2.5.6 Stress Leukogram and Inflammatory Leukogram Changes
2.5.7 The Neutrophil-to-Lymphocyte Ratio (NLR) and Its Utility in Humans and Small Animals
2.6 Aimy and Hypothesis
3. Own Publications
3.1 The Blood Neutrophil-to-Lymphocyte Ratio (NLR) as a Diagnostic Marker in Dogs with Chronic Enteropathy
3.2 Evaluation of the Blood Neutrophil-to-Lymphocyte Ratio (NLR) as a Diagnostic and Prognostic Biomarker in Dogs with Portosystemic Shunt
4 Discussion
4.1 Objective of the study
4.2 Discussion of the results
4.3 Limitations of the study
4.4 Conclusions
5. Summary
6. Zusammenfassung
7. References
8. Acknowledgement
Entity Resolution on Heterogeneous Knowledge Graphs
No full textWith the ever-growing size of the internet, the need for structured information is growing alongside the web. Knowledge Graphs (KG) aim to address this information need by enabling users to dynamically represent complex relationships in a semantically enriched data structure. Typically, such graphs encompass information from various domains or data sources, which often necessitates merging two KGs. This involves identifying the same real-world entities and concepts across the separate sources, a process known as Entity Resolution (ER).
While the flexibility and dedicated graph structure are great for modeling complicated information, it is challenging for data integration tools to handle the heterogeneous schemata and utilize the rich relational information present in the KGs. A recent trend that addresses this issue is to utilize Knowledge Graph Embeddings (KGE) to transform the information of the KG into dense vectors, translating the semantic and relational similarity between entities into distances between the entity embeddings in the vector space. Even though this research area is relatively new, improvements have been seen at a neck-breaking pace.
Still, KGE-based Entity Resolution suffers from a variety of problems. The early methods, in particular, mainly incorporated the graph structure into the matching process treating entity attribute values as second-class citizens. Therefore, in our EAGER framework, we aimed to investigate the possibilities of using KGEs in conjunction with attribute similarities as input for a variety of machine learning models.
We introduced a new dataset family from the movie and TV show domain with a shallow graph structure. In conjunction with datasets sampled from open KGs like DBpedia and Wikidata, we were able to evaluate our approach on a spectrum graph densities. While attribute similarities on their own are better for shallow graphs, and KGEs on their own are better for more densely connected graphs, our results show that we generally obtained significantly better results when combining KGEs with attribute similarities than either on their own. Overall, our combination approach significantly outperformed state-of-the-art matching frameworks designed for tabular data.
KGE-based matching is largely focused on learning the embeddings. In the final step, the nearest neighbors are used to obtain the matching candidates. This is usually done using metrics like cosine similarity or Euclidean distance in the vector space. A problem of high-dimensional data like embeddings is hubness, which means that some data points become nearest neighbors of many other data points. At the same time, some entities are nearest neighbors of none. This is detrimental to match quality since, typically, one entity from one data source is matched with one or, at most, a few entities in the other data source. To address this problem we investigated hubness reduced nearest neighbor search in our kiez framework. We reduce speed penalties incurred by the hubness reduction by relying on Approximate Nearest Neighbor search (ANN).
Our results show that using ANN allows us to reap the quality benefits of hubness reduction while sacrificing practically nothing in terms of speed.
One major bottleneck of ER lies in its quadratic complexity a-priori, i.e., all entities of one data source must be compared with all entities of the other data source. A common solution to this problem is to include a blocking step. Here, likely matching entities are placed into the same block and comparisons are then only performed inside the block.
Traditionally blocking comes from the world of databases, which is not capable to deal with the heterogeneity of the schemata of KGs and ignores the rich relational structure that makes this data structure so powerful. Furthermore, most blocking approaches rely on symbolic techniques, e.g., overlap on token level. Embeddings of language models can capture the semantics of attribute information and enable clustering of similar concepts that might be dissimilar when solely relying on string metrics. For our framework named klinker we therefore expand a relational blocking approach to enable the use of embedding-based approaches and conversely expand deep learning-based tabular blockers to incorporate relational information. We are then able to investigate relational blocking on the neuro-symbolic spectrum. Our results show that our relational enhancements to state-of-the-art approaches significantly improve the results.
The implemented (neuro-)symbolic methods can outperform even sophisticated deep-learning-based methods in terms of quality and speed. Our newly implemented hybrid methods that combine symbolic and embedding-based techniques show promising directions for future research.
We make all our results publicly available as open-source libraries.
The significance of our results is ensured by utilizing a rigorous Bayesian statistical testing regime
The relationship between myopia and near work, time outdoors and socioeconomic status in children and adolescents
No full textThis study examined environmental and social risk factors for myopia in over 1400 children aged 3–18 in Leipzig, Germany. It found that less frequent outdoor activity and longer durations of near work were significantly associated with a higher risk of myopia, even after accounting for age, sex, and socioeconomic status. Daily outdoor time and limiting long near work sessions may help prevent myopia, suggesting the need for preventive strategies at all ages.:Abbreviations and Acronyms
1 Introduction
1.1 Background
1.1.1 Epidemiology
1.2.2 Definition
1.1.3 Emmetropization
1.1.4 Genetic Factors
1.1.5 Mechanisms of Eye Growth
1.1.6 Historical Context
1.2 State of Research
1.2.1 Time Outdoors
1.2.2 Near Work
1.2.3 Social Status
1.3 LIFE Child
2 Study Rationale
3 Publication
4 Summary
5 References
Statement of Contribution
Declaration of Originality
Curriculum Vitae
List of PublicationsIn dieser Studie wurden Umwelt- und soziale Risikofaktoren für Myopie bei über 1400 Kindern im Alter von 3 bis 18 Jahren in Leipzig untersucht. Es zeigte sich, dass seltener Aufenthalt im Freien und längere Phasen von Naharbeit signifikant mit einem höheren Risiko für Myopie verbunden waren – unabhängig von Alter, Geschlecht und sozioökonomischem Status. Tägliches Sonnenlicht und die Begrenzung von ausgedehnter Naharbeit könnten demnach zur Vorbeugung von Myopie beitragen. Präventionsmaßnahmen sollten altersübergreifend erfolgen.:Abbreviations and Acronyms
1 Introduction
1.1 Background
1.1.1 Epidemiology
1.2.2 Definition
1.1.3 Emmetropization
1.1.4 Genetic Factors
1.1.5 Mechanisms of Eye Growth
1.1.6 Historical Context
1.2 State of Research
1.2.1 Time Outdoors
1.2.2 Near Work
1.2.3 Social Status
1.3 LIFE Child
2 Study Rationale
3 Publication
4 Summary
5 References
Statement of Contribution
Declaration of Originality
Curriculum Vitae
List of Publication
Infrastrukturbedarfe und Hemmnisse: Ergebnisse der Kommunalbefragung 2024
No full textIn weiten politischen, gesellschaftlichen und wissenschaftlichen Kreisen besteht der Konsens, dass Bund, Länder und Kommunen in den kommenden Jahren gezielt zusätzlich investieren müssen, um Infrastruktur, Wirtschaft und Gesellschaft zukunftsfähig zu machen. Trotz einer Belebung des Investitionsgeschehens auf der kommunalen Ebene sind die realisierten Ist-Investitionen in den vergangenen 20 Jahren i. d. R. hinter den infrastrukturellen Bedarfen zurückgeblieben. Kommunalbefragungen bieten in diesem Kontext eine wertvolle Ergänzung zu öffentlichen Statistikdaten, indem sie entscheidungsrelevante Informationen zu Investitionsbedarfen und infrastrukturellen Herausforderungen liefern.
Vor diesem Hintergrund führt das KOMKIS im zweijährigen Turnus eine Kommunalbefragung durch, um die Investitions- und Instandhaltungsbedarfe im Freistaat Sachsen systematisch zu erfassen. Der vorliegende KOMKIS Report Nr. 13 fasst die Ergebnisse der parallel erschienenen KOMKIS Analyse 29 zusammen
Within- and between-subject consistency of perceptual segmentation in periodic noise: A combined behavioral tapping and EEG study
No full textIt is remarkable that human listeners can perceive periodicity in noise, as the isochronous repetition of a particular noise segment is not accompanied by sali-ent physical cues in the acoustic signal. Previous research suggested that listeners rely on short temporally local and idiosyncratic features to perceptually segmen tperiodic noise sequences. The present study sought to test this assumption by disentangling consistency of perceptual segmentation within and between listeners. Presented periodic noise sequences either consisted of seamless repetitionsof a 500-ms segment or of repetitions of a 200-ms segment that were interleaved with 300-ms portions of random noise. Both within- and between-subject consistency was stronger for interleaved (compared with seamless) periodic sequences.The increased consistency likely resulted from reduced temporal jitter of poten-tial features used for perceptual segmentation when the recurring segment was shorter and occurred interleaved with random noise. These results support the notion that perceptual segmentation of periodic noise relies on subtle temporally local features. However, the finding that some specific noise sequences were seg-mented more consistently across listeners than others challenges the assumption that the features are necessarily idiosyncratic. Instead, in some specific noise samples, a preference for certain spectral features is shared between individuals
