Publikationer från Linköpings universitet
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Octonion algebras over schemes and the equivalence of isotopes and isometric quadratic forms
No full textOctonion algebras are certain algebras with a multiplicative quadratic form. In [1], Alsaody and Gille show that for octonion algebras over unital commutative rings there is an equivalence between isotopes and isometric quadratic forms. The contravariant equivalence of unital commutative rings and affine schemes leads us to a question: can the equivalence of isometry and isotopy be generalized to octonion algebras over a not necessarily affine scheme? We present the basic definitions and properties of octonion algebras, both over rings and over schemes. Then we show that an isotope of an octonion algebra Cover a scheme is isomorphic to a twist by an Aut(C)-torsor. We conclude the paper by giving an affirmative answer to our question
When Two Becomes Three: Predicting Stable Ternary Boron-Based Compounds by Populating Unique Lattice Sites in Binary Prototype Structures
No full textBoron-based materials are known for their excellent mechanical properties and structural versatility. However, the discovery of such novel materials is often hindered by challenging synthesis procedures, such as high temperature and pressure, which is why theoretical guidance can be used to identify candidates most promising for synthesis. In this study, new chemical phase spaces are explored utilizing the Materials Project database. 16 boron-based binary prototype structures are identified, each featuring two unique non-boron lattice sites. These sites are subsequently populated with elements from Groups 2 to 14 and expanded into 27 552 ternary compounds. Phase stability assessments identify 166 stable ternary compounds, 155 of which are mechanically stable. Analysis reveals a strong correlation between boron concentration and mechanical properties, with boron-rich compounds exhibiting higher Vickers hardness and improving shear and Young's moduli. Notably, multiple ternary compounds demonstrate significant mechanical property enhancements over their binary counterparts, with some showing Young's modulus improvements of up to 50%. These findings exemplify a pathway for designing novel boron-based materials with exceptional mechanical characteristics.Funding Agencies|Knut och Alice Wallenbergs Stiftelse [2022-06725]; Swedish Research Council [KAW 2020.0033]; Knut and Alice Wallenberg (KAW) Foundation for a Scholar Grant</p
Development of early acquired arithmetic skills and development of reading comprehension facilitate the development of later developing arithmetic skills
No full textThis longitudinal study tested the notion of a hierarchy of maths skill development by examining whether the development of later acquired arithmetic skills rely on development of earlier acquired arithmetic skills. The scores of 307 children on single-digit arithmetic, multi-digit calculation, arithmetic word problem-solving, and reading comprehension obtained at two measurement points were analysed with latent change score models computed to extract individual development change scores, for further analysis using multiple regression. The results provide clear support of the assumption of a hierarchy of maths development as developmental change in single-digit arithmetic was predictive of developmental change in calculation, and developmental change in arithmetic word problem-solving was supported by developmental change in both single-digit arithmetic and calculation. Developmental change in reading comprehension was also uniquely predictive of two aspects of arithmetic developmental change suggesting that formal mathematics requires support from language processes.Funding Agencies|Swedish Council for Working Life and Social Research [2010-0078]</p
Coherent Phonons, Localization, and Slow Polaron Formation in Lead-Free Gold Perovskite
No full textLead-free metal halide perovskites are emerging as less-toxic alternatives to their lead-based counterparts. However, their applicability in optoelectronic devices is limited, and the charge transport dynamics remain poorly understood. Understanding photo-induced charge and structural dynamics is critical for unlocking the potential of these novel systems. In this work, ultrafast optical and Raman spectroscopy combined with band structure calculations are employed to investigate the coupled electronic and vibrational dynamics in Caesium gold bromide, a promising lead-free perovskite. It is found that the band-edge charge transfer states are strongly coupled to Au & horbar;Br stretching phonon modes, leading to frequency modulation of absorption by coherent phonons. Early-stage relaxation is characterized by dynamics of delocalized charge transfer excitation and slowly decaying coherent phonons. The electronic and vibrational relaxation reveals a slow formation of a localized polaronic state in the 10-20 ps timescale. Using a displaced harmonic oscillator model, the polaronic binding energy is estimated to be approximate to 80 meV following lattice relaxation along the phonon modes. Strong exciton-phonon coupling and slow polaron formation via coupling to lattice modes make this material a promising testbed for the control of coherent phonons and localized polaronic states using light.Funding Agencies|Vetenskapsrdet [P2020-90219, P2020-90215]; Swedish Energy Agency [2021-05207, 2023-05244]; Swedish Research Council; KAW WACQT program [NAISS 2023/5-276, 2024/5-372]; NanoLund</p
Hate crime disclaimers : barriers to education and policing of hate crimes in Sweden
No full textPolicing hate crimes presents numerous challenges. Police officers play a crucial role in the initial identification of these crimes, yet a lack of knowledge and training often hampers their ability to do so effectively. Despite increased attention to hate crimes over the past decades, the effectiveness of targeted police training remains underexplored. This study examines the barriers faced by Swedish police trainees in recognising hate crimes during a 5-week course on hate crime and discrimination. Drawing on trainees’ accounts and reinterpretations of racist and homophobic hate crimes, the article identifies and codes six central disclaimers that serve to disqualify a crime as a hate crime: the trivialisation disclaimer, the lack-of-evidence disclaimer, the not-the-only-motive disclaimer, the perpetrator’s-mental-status disclaimer, the victim-blaming disclaimer, and the ingroup-bias disclaimer. These disclaimers provide insights that can enhance police education and the initial investigation process of hate crimes. The study also discusses how these barriers to recording hate crimes can impact the investigation process
Defect attention-based lightweight real-time adaptable surface defect analysis
No full textSurface defect diagnosis for steel sheets is essential to maintain the quality of the product. However, it is challenging to do such a task due to the high manufacturing speed of 100-140 m/min, making it impossible to observe defects visually. However, developing a lightweight and real-time adaptable intelligent approach can both overcome this issue and satisfy the requirements of the concept of Industry 4.0. Based on that motivation, this study aimed to satisfy such a demand by introducing an attention-based surface defect identification approach called MobileNetV2-AGCA and UNET-AGCA for defect localisation. The effectiveness of the proposed techniques was evaluated by considering steel strip surface defect images of the NEU-CLS and NEU-DET surface defect dataset where six different defects are included. The Adaptive Graph Channel Attention (AGCA) Module was implemented in an edited version of MobileNetV2 and UNET architecture to improve segmentation accuracy while maintaining or improving the execution speed. According to the experimental results, MobileNetV2-AGCA successfully identified the surface defects with an average accuracy of 99.72%. Regarding defect localisation, UNET-AGCA reached an F1 score of 0.795. It is concluded that the proposed methods provided promising results to be applied to a real-time problem related to surface defect identification and localisation
Not by a long chalk : A case study of the chalk stream restoration work of the Upper River Ivel, Hertfordshire
No full textChalk streams are universally extraordinary mineral rich waters and unique to England as most of them run through there. However, due to anthropogenic activities many are endangered, and the government has declared an emergency. There is now a strategy in place for restoring and recovering the health of chalk streams nationally. But the outcome of chalk stream restoration work is often vague, and three variables are needed to ensure a successful restoration. In a local context there may be factors affecting the restoration. With a social science approach, this case study seeks to find the setbacks and solutions on one of the most pressured chalk streams examples there are: The Upper River Ivel (URI), Hertfordshire, where a restoration project has just taken place. Via a thematic analysis any challenges or opportunities on the restoration and future of the URI was unfolded. By interviewing stakeholders connected to the restoration, results shed light to themes around the complex nature of the URI case, its restoration and future. The research shows that the hinders are intercorrelated to the solutions to the issues the URI is facing. The themes show a focus on 1) resources 2) monitoring and data 3) awareness 4) water valuation 5) water quality 6) water quality, and 7) maintenance. Although there is a consensus between the stakeholders about the aim for the URI and that the project has been positive, the time perspective on when to reach there is where there are various opinions.
Transformation of the images of Kings : Images of KarlXI and Karl XII based on Swedish history textbooks 1885-2014
No full textStudien är en redogörelse av hur läroböcker förändras i innehåll och historieskrivning under dryga 100 år. Den visar på hur olika författare framställer och berättar om två betydelsefulla kungar inom svensk historia. Syftet är att utifrån en innehållsanalys beskriva och analysera skildringar av Karl XI och Karl XIIi läroböcker i historia mellan 1885–2014.De huvudsakliga frågorna berör hur mycket som skrivits omkungarna i läroböckerna, hur de framställs, det vill säga om det är aktörsdriven eller händelsedriven historia samt hur bilden av dessa kungar förändras över tid. Nyfikenheten drivs av tankar kring hur texter förändras genom till exempel omvälvande samhällsförändringar eller förändringar i synsätt som nya författare tar med sig i omskrivningar eller revideringar i befintliga texter. Men undersökningen kommer fokusera kring hur mycket, vad och på vilket sätt författarna väljer att beskriva historien kring två av Sveriges mest omskrivna kungar. Resultatet visar hur läroböcker gått från attfokusera mer på historiens stora män och deras egenskaper, till att belysa historiens utveckling genom händelsedrivna förklaringar och objektiva fakta.
Do LiU researchers publish data – and where? Dataset analysis using ODDPub
No full textSwedish researchers are encouraged to share their research data, with a government goal for all publicly funded research to provide open research data by 2026. Hoshi Larsson (2023) investigated the extent and location of research data from LiU researchers. However, the search was limited to datasets with DOIs listed in DataCite Commons, suggesting that many datasets were excluded in the investigation. Therefore, the purpose of this study is to identify, through articles’ descriptions of open data, to what extent LiU’s researchers are sharing their research data and open code, and if so, which repositories they use for sharing data. This report analyzed LiU articles parallel published in the institute's repository DiVA in 2022 using the ODDPub text-mining algorithm to determine the extent and repositories of LiU researcher’s open research data. The results showed that approximately 10 percent of the articles mentioned data availability, and almost two thirds of the openly shared datasets were in subject-specific repositories. Additionally, 90 percent of LiU's parallel published articles did not mention data availability. The mismatch between data sharing articles detected in Hoshi Larsson (2023) and in this report suggests that findability remains low. The university library should guide researchers on the benefits of data sharing and the importance of findability and provide support in making their research data accessible.Dataset for this report:Hoshi Larsson, K. (2025). Dataset for "Do LiU researchers publish data – and where? Dataset analysis using ODDPub" [Data set]. Zenodo. https://doi.org/10.5281/zenodo.15017715The cover and the first pages were updated in November 2025 when the report was retroactively included in the series.The first version have been downloaded 103 times.2025-12-18: The author has made a change to the abstract (removed one sentence).</p
Selection for tameness alters play-like behaviour in red junglefowl in line with effects of domestication
No full textThe phenotypic alterations brought by domestication have been hypothesized to be driven by selection for tameness. To explore this, we selected red junglefowl (RJF) for high (HF) and low (LF) fear of humans for 14 generations. We previously found that domesticated chickens performed more play-like behaviours during early ontogeny, and therefore, in this study, we explored potential effects of tameness. Groups of three to four chicks were randomly created from each selection line, and each group was moved to an enriched play arena twice per week, from day 6 until day 53 post-hatch. The frequency of 14 different play-like behaviours, categorized as locomotor, social and object play-like behaviour were recorded for 30 min at every observation instance. Every group of three or four birds constituted the independent statistical replicates and measures were averaged within the groups. The frequency of total play-like behaviour as well as object, and locomotor play-like behaviour was significantly higher in LF, while social play-like behaviour was significantly more common in HF. This largely mirrors previous observations of differences between domesticated and ancestral chickens. Hence, our results support the important role of tameness for the evolution of domesticated behaviour.Funding Agencies|Olle Engkvists Stiftelse [231-0032]; Swedish Research Council [2019-04869]</p