openHSU – Research Showcase

4943
Research outputs
866
People
140
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111
Projects
37
Conferences
20
Journals
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  • Publication
    Open Access
    Galois Theory and Hilbert Irreducibility Theorem
    (Sardar Vallabhbhai National Institute of Technology, 2025) ;
    Jana, Ranjan Kumar
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    Thangadurai, Ravindranathan
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    Sardar Vallabhbhai National Institute of Technology
    In this dissertation, we are studying abstract algebra; mostly, our focus is on studying Galois theory in depth, and then we will study the proof of our main theorem, "Hilbert Irreducibility Theorem," which states that given any irreducible polynomial g (t_1, t_2,...., t_n, x) over the rational numbers, there are an infinite number of rational n-tuples (a_1, a_2,...., a_n) such that f (a_1, a_2,..., a_n, x) is irreducible over the rational numbers. I have omitted the basics of abstract algebra, such as group, ring, and field theory, and motivated the reader to read a basic book to learn these topics. I have presumed that the reader knows linear algebra. I started my dissertation with an introduction to group characters and then extended our discussion to Galois extension and normal extension to provide the basis for studying the Fundamental Theorem of Galois Theory. Then, we fixed our focus on Kummer Extensions and Cyclotomic Extensions. To end our discussion of Galois' theory, we studied solvable groups. Then some complex analysis theorems have been stated, which we will use in our proof of Hilbert's irreducibility theorem. A whole chapter has been dedicated to studying lemmas to prove our theorem, and then in the last chapter, we have proved our theorem.
  • Publication
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    China and the limits of hypothetical hegemony
    (Taylor & Francis, 2024-02-29)
    How is China’s rise leaving its mark on the practices, norms and institutions of international politics? In their article, “China and the Logic of Illiberal Hegemony”, Darren J. Lim and G. John Ikenberry offer a provocative answer to this question. Lim and Ikenberry set out to identify “the logic and practices of an ideal-type order that most closely suits China’s preferences.” They distil three organizational principles or logics that could characterize a potential Chinese model of international order: the logic of difference, the logic of win-win, and the logic of partnerships. The authors argue that while such logics may not be illiberal per se, by attracting autocratic state followers and being based on pragmatic interstate bargaining rather than formal institutions, they may generate illiberal outcomes over time. If this argumentation holds, it raises considerable doubt about the sustainability of liberal international order in the face of China’s continued rise.
  • Publication
    Metadata only
    How much can we improve two-section watch bills?
    (Sage, 2023-10-19)
    Röttger, Stefan
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    Giesche, Melanie
    ;
    Abendroth, Johanna
    ;
    ;
    Matsangas, Panagiotis
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    Shattuck, Nita Lewis
    A traditional two-section watch bill (6 hours on / 6 hours off, starting at midnight – “6/6”) and a two-section watch bill better adapted to the human circadian rhythm (watches of 7, 5, 5, and 7 hours duration, starting at 3 a.m. – “7-5-5-7”) were trialed on two vessels of the German Navy with 67 study participants in a crossover design. Questionnaires were used to assess subjective sleepiness (ESS, KSS) and subjective fatigue (FSS). The psychomotor vigilance task (PVT) was self-administered with wearable devices before and after each watch. Over the course of seven days at sea, PVT performance worsened significantly with the 6/6, but not with the 7-5-5-7 watch bill. In the 6/6 watch bill, number of participants with excessive sleepiness and high levels of fatigue was higher than in the 7-5-5-7 watch bill although not at a statistically significant level. Marked differences between watch bills in crew performance started to emerge after 6 days.
  • Publication
    Open Access
    Hey CLIP, can you capture semantics in brand names?
    (Tilburg University, 2023) ;
    Cassani, Giovanni
    ;
    Tilburg University
    ;
    Garrido Alhama, Raquel
    Congruence between brand names and other flagships of a brand are important tools to effectively communicate to, and set the right expectations in consumers. In this study, we explore congruence of brand features as a problem that could potentially be evaluated by computational models trained on cross-modal stimuli such as CLIP. As a by-product we explore to what extent these models capture sound symbolic associations in our stimuli set, and analyse the relationship between (sub-) lexical information and shape dimensions in brand logos. Instead of human participants, we employ CLIP- and BERT-based computational models to make decisions about similarity between a multitude of brand names, brand descriptions and brand logos. We show that our results support proposals of statistical co-occurrence as an underlying mechanism of sound symbolic associations, and argue that CLIP can be carefully used as a tool for maneuvering through naming and logo design decisions.
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  • Publication
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    Cognitive profiles of adolescent inpatients with substance use disorder
    (MDPI, 2022-05-21) ;
    Lüken, Luisa Marie
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    Kelker, Lea
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    Holtmann, Martin
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    ;
    Legenbauer, Tanja
    The prevalence of substance abuse is high during adolescence, and several studies have linked the use of alcohol and cannabis in adolescence to different cognitive impairments. To investigate whether specific cognitive deficits can be observed in adolescents with substance use disorder (SUD), we compared the cognitive profiles of inpatient adolescents diagnosed with SUD to a control group matched for sex, age and educational status. The inpatient adolescents received diagnoses of cannabis use disorder, alcohol use disorder or both. We compared the WISC-V profiles of 22 inpatients (45.5% female, Mage: 14.5; SD: 0.8) and the WAIS-IV profiles of 27 inpatients (44.4% female, Mage: 17.1; SD: 0.9) to 49 matched control participants with no diagnosed SUD. At the time of testing, participants were hospitalized for treatment of their SUD and were abstinent for a period of at least 6 weeks. To gain greater power, we jointly analyzed the Verbal Comprehension Index, Working Memory Index, Processing Speed Index and Full Scale IQ as assessed by WISC-V and WAIS-IV. The clinical group performed significantly worse than the control group on all the above indices. When only the group of inpatients was observed, in a model with the factors sex, educational status, presence of a comorbid diagnosis of depression and the number of comorbid diagnoses, only the factor educational status was significantly associated with the Full Scale IQ, whereas the factors sex and a comorbid diagnosis of depression in this group were associated with the Processing Speed Index. The results show that adolescents diagnosed with SUD (cannabis and/or alcohol) display broad cognitive impairments after 6 weeks of abstinence. Future research is required to further explore the role of comorbid diagnoses.
  • Publication
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    Entwicklungsstörungen in der Kindheit
    (Hogrefe, 2022-07-19) ;
    Koglin, Ute
    Entwicklungsstörungen beziehen sich auf globale oder spezifische (umschriebene) Abweichungen von Verhalten oder Fähigkeiten. Sie haben ihren Ursprung in der Kindheit. Durch die im DSM 5 und ICD-11 neu eingeführte Bezeichung als Neuroentwicklungsstörungen wird deutlich, dass die Störungen auch aufgrund ihrer hohen gemeinsamen Anteile in der Symptomatik und der bedeutsamen Komorbiditäten eher über eine dimensionale Betrachtung zu verstehen sind. Analysen von Krankenkassendaten lassen die Schlussfolgerung zu, dass Entwicklungsstörungen mit 17 % die mit Abstand häufigste Diagnose psychischer Störungen im Kinder- und Jugendbereich darstellen. Ursachen und Risikofaktoren für Entwicklungsstörungen erweisen sich als heterogen, jedoch mit einem engen Bezug zur neuronalen Entwicklung. Nicht nur die Entwicklungsstörungen oder Verhaltensstörungen in der Kindheit an sich, sondern auch die häufig damit assoziierten negativen Folgen für den Alltag können sich deutlich auf die Lebensqualität von betroffenen Kindern und ihren Familien auswirken. Elterliche Belastungen und famliliärer Stress im Kontext einer Entwicklungsstörung des Kindes können zusätzlich dazu beitragen, dass sich die wahrgenommene gesundheitsbezogene Lebensqualität verringert. Gezielte Interventionen können dazu beitragen, Familien zu entlasten und die Lebensqualität zu verbessern.
  • Publication
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    Structural equation modeling of common cognitive abilities in preschool-aged children using WPPSI-IV and BRIEF-P
    (MDPI, 2022-07-21)
    Fiedler, Sören
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    Krüger, Nina
    ;
    Various studies have addressed the relationship between intelligence and executive functions (EF). There is widespread agreement that EF in preschool children is a unitary construct in which the subordinate factors of Updating, Inhibition, and Shifting are still undifferentiated and correlate moderately with a general factor of intelligence (g). The aim of this study is to investigate the common structural relationship between these two constructs using confirmatory factor analysis. Furthermore, we intend to close the gap of more daily life-associated executive functions and replicate findings in preschool-aged children. Data from a sample of N = 124 average developed children without severe impairments (aged 4 years 0 months–6 years 11 months) were analyzed using the data pool of the standardization and validation studies on the German Wechsler Preschool and Primary Scale of Intelligence—Fourth Edition. Additionally, Executive functions were assessed using a standardized parent-completed questionnaire (BRIEF-P) on their children’s everyday behavior. A second-order factor solution revealed that a model with a loading of the common factor of general intelligence (g-factor) onto the EF factor fits the data best. To specify possible method effects due to different sources of measurements, a latent method factor was generated. The results indicate a heterogeneous method effect and a decreasing factor loading from g on to EF while controlling for the method factor.
  • Publication
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    Accounting for intraindividual profiles in the Wechsler Intelligence Scales improves the prediction of school performance
    (MDPI, 2022-10-27)
    Lenhard, Alexandra
    ;
    IQ scores are often used to predict school performance. However, for children with learning disabilities, the predictive validity of IQ scores appears to be low. In the fourth and fifth versions of the Wechsler Intelligence Scales for Children (WISC), new ancillary indices were introduced. The General Ability Index (GAI) is a broad measure of fluid reasoning with verbal, visual–spatial, and figural test items. By contrast, the Cognitive Proficiency Index (CPI) combines different executive functions known to be frequently affected in children with dyslexia, ADHD, or combined learning disorders. To date, there is little evidence to demonstrate that these measures improve the prediction of school performance beyond the Full-scale IQ (FSIQ). We therefore used lasso regression to explore the predictive validity of these measures for school grades. The analyzed samples were taken from the German standardization samples of the WISC-IV and the WISC-V. In most cases, the prediction of school performance was not considerably improved by taking the GAI or the CPI into account. However, when the individual discrepancy between the CPI and the GAI was high, the FSIQ lost its predictive validity in elementary school. In this subgroup of children, reading and writing skills were best predicted by the CPI, whereas math skills were limited by the lowest score (i.e., the minimum out of the CPI and the GAI).
  • Publication
    Metadata only
    Does the association between preschool media use and language difficulties at school entry vary by first language of the child and parental education?
    (MDPI, 2023-11-25)
    Hammrich, Chiara Maria
    ;
    Götz, Simon
    ;
    ;
    Weyers, Simone
    Background: Both media use and social background affect children’s language development. The aim of this study was to explore the association between media use and different aspects of language difficulties (grammar, auditory memory, articulation) and social background (first language (FL), parental education (PE)) in more detail. Methods: We analyzed data from 4015 children from the 2013/14 school entry examination in a Western German city. Media use, FL, and PE were assessed by social history, and language difficulties by sociopediatric screening. We calculated Prevalence Ratios with a 95% Confidence Interval for language difficulties by media use and FL/PE; compared models with and without interaction terms; and estimated the predicted prevalence of language difficulties by media use and FL/PE. Results: Children with non-German FL/low PE had a higher media use and more language difficulties. However, the gradual association between media use and grammatical abilities/recommendation of training was more pronounced in children with German FL and medium/high PE. e.g., especially in the preposition subtest. Conclusions: The association between media use and language difficulties varies regarding different aspects of social background and language difficulties. Still, extensive media use is linked with language difficulties for all children. The media competence of young families remains crucial in times of digitalization.