Publikationer från Uppsala Universitet
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Tracing chemical depletion in evolved binaries hosting second-generation transition discs
No full textThe mechanisms responsible for chemical depletion across diverse astrophysical environments are not yet fully understood. In this paper, we investigate chemical depletion in post-AGB/post-RGB binary stars hosting second-generation transition discs using high-resolution optical spectra from HERMES/Mercator and UVES/VLT. We performed a detailed chemical abundance analysis of six post-AGB/post-RGB stars and six post-AGB/post-RGB candidates with transition discs in the Galaxy and in the Large Magellanic Cloud. The atmospheric parameters and elemental abundances were obtained through 1D LTE analysis of chemical elements from C to Eu, and 1D NLTE corrections were incorporated for elements from C to Fe. Our results confirmed that depletion efficiency, traced by the [S/Ti] abundance ratio, is higher in post-AGB/post-RGB binaries with transition discs compared to the overall sample of post-AGB/post-RGB binaries. We also examined correlations between derived abundances and binary system parameters (astrometric, photometric, orbital, pulsational). Additionally, we compared the depletion patterns in our sample to those observed in young stars with transition discs and in the interstellar medium. We confirmed that the depletion is significantly stronger in post-AGB/post-RGB binaries with transition discs than in young stars with transition discs. Furthermore, we found that [X/Zn] abundance ratio trends of volatile and refractory elements in post-AGB/post-RGB binaries with transition discs generally resemble similar trends in the interstellar medium (except for trends of [Si/Zn] and [Mg/Zn] ratios). These findings, although based on a limited sample, provide indirect constraints for depletion mechanism in circumbinary discs around post-AGB/post-RGB stars
Design of auxetic metamaterial for enhanced low cycle fatigue life and negative Poisson's ratio through multi-objective Bayesian optimization
No full textAuxetic metamaterials (AM) with negative Poisson's ratio (NPR) offer promising mechanical properties but often suffer from significant stress concentrations, compromising durability and fatigue life. Conventional design approaches, including topology optimization and empirical geometry-based methods, struggle with exploring complex design spaces, while data-driven techniques demand extensive datasets, making fatigue life prediction computationally expensive. To address these challenges, we propose a novel framework that integrates Be<acute accent>zier curve-based geometric parameterization, multi-objective Bayesian optimization (MBO), and fatigue life prediction via elastoplastic homogenization and critical distance theory. This approach systematically explores the design space, simultaneously enhancing NPR and optimizing fatigue resistance while alleviating localized stress concentrations. MBO efficiently balances exploration and exploitation with limited data, making it particularly suitable for computationally intensive fatigue analysis. Optimized AM structures exhibited an 85.11% increase in NPR and a 12.07% improvement in low-cycle fatigue (LCF) life compared to initial designs. Experimental validation confirmed up to 30 times the LCF life and a 2.5-fold NPR increase over conventional AM structures. These findings establish a scalable methodology for AM design, advancing the development of durable, highperformance metamaterials for biomedical, aerospace, and energy-harvesting applications
Regulation of β-cell function through the primary cilium
No full textPrimary cilia are rod-like sensory organelles extending from the surface of most mammalian cells, and recent studies indicate they play critical roles in islet cell function and hormone secretion. Their sensory ability is achieved by specific receptors that initiate signal transduction within the cilium, enabling localized signaling events that can propagate into the cell and modulate its function. Using intact mouse and human islets, we show that GABA and somatostatin, two major paracrine factors in the islet microenvironment, exert their effects through ciliary receptors. We found that GABAB1 receptors were enriched at the ciliary base, but mobilized distally upon GABA binding and selectively induced ciliary Ca²+ influx via activation of voltage-dependent Ca²+ channels. At the same time, cytosolic Ca²+ increases were prevented from propagating into the cilium due to enhanced Ca²+ extrusion at the cilia base, thus isolating the cilium from cytosolic Ca2+ signals. Somatostatin, secreted from islet δ-cells, directly activated ciliary SSTR3 receptors on neighboring β-cells as a consequence of their close proximity within the islet microenvironment. This localized signaling resulted in a rapid reduction of cAMP specifically within the cilium, promoting sustained nuclear entry of the cilia-dependent transcription factor GLI2. This mechanism operated in parallel with the canonical Hedgehog pathway and was critically dependent on ciliary Ca2+ signaling. We further showed that somatostatin was released directly onto β-cell cilia in intact islets, establishing primary cilia as a key site for paracrine regulation of β-cell function. Islets isolated from patients with type-2 diabetes were found to contain cells with reduced cilia length, which in turn led to reduced proximity between β-cell cilia and islet δ-cells. Additionally, cGMP was identified as another important ciliary second messenger. Both GLP-1 and atrial natriuretic peptide stimulated cGMP formation in β-cells, and the nucleotide freely diffused into the cilium, where it triggered increases in Ca2+ at least in part through activation of cyclic nucleotide-gated channels. Moreover, cGMP increases, similar to cAMP reductions, induced stable nuclear translocation of GLI2, indicating intricate interdependence of cAMP and cGMP signaling that may converge on ciliary Ca2+. These findings highlight the primary cilium as a specialized and unique signaling compartment for integrating and interpreting paracrine, endocrine and intracellular cues, with important implications for islet cell function
Killing With Kindness: A Comparative Study of the Impact of Targeted Killings on Peace Processes
No full textEnchanted Reception : Religion and the Supernatural in Medieval Troy Narratives
No full textThis volume offers a series of cross-cultural, in-depth studies of twelfth- to fifteenth-century medieval Troy narratives, mainly romances. Source texts are situated across a wide range of language traditions and include famous literary highlights (e.g. Benoît, Guido, Tzetzes and Eustathios) as well as lesser-known work (e.g. the Irish tradition) and expert comparative analyses within the same language traditions (e.g. Middle English, German). With a unique synchronical focus, it highlights the classical reception of religious and supernatural elements, events and characters in the Middle Ages, embedded in the contemporary socio-cultural (notably Christian-political) ideological context. The volume subscribes to the transnational perspective that has long since proven its relevance for medieval studies and actively builds bridges between the ‘eastern’ Byzantine and ‘western’ vernacular traditions, which on a scholarly level are often still segregated
The Digital Horizon : A Study of the Digitalisation of Swedish Museums and the Policies Governing Them in the 21st Century
No full textThis thesis examines the intersection of digitalisation efforts within Swedish museums, cultural heritage policies, and academic research to understand their mutual influences and potential challenges. By employing a Hermeneutic method to analyse policy documents and conducting interviews with museum professionals, this research investigates how digitalisation is talked about in policy documents, research and how it is utilised in museums, and if there is a connection of information between these parties. The aim is to shed light on the extent to which the findings and insights obtained from research are being utilised in the real-world context of Swedish museums and policies. While Swedish policymakers advocate digital transformation to enhance accessibility, engagement, and preservation, findings suggest a complex reality in which museum professionals navigate limited resources and communication gaps with governing agencies. These contrasts highlight a need for stronger collaboration and communication among policymakers, museum professionals, and researchers to harness digitalisation's potential fully. In response, this thesis advocates for increased knowledge-sharing and strengthened communications to bridge these divides and foster digital competence within the museum sector. This study contributes to the academic discourse on digital cultural heritage by underscoring the importance of clear policy frameworks that reflect both scholarly insights and the operational realities faced by museums, ultimately suggesting pathways toward a more integrated and sustainable approach to digitalisation in cultural heritage institutions
Methodology for Multiparameter Evaluation of Barriers Against Proliferation of Minor Actinides
No full textThere exist elements apart from uranium and plutonium that could potentially be used to construct the core of a nuclear explosive device. These belong to the so-called minor actinides (MAs), which exist in nonnegligible amounts in spent nuclear fuel (SNF) and are in nearly all cases not covered by international safeguards. Future reprocessing of SNF could result in significant separation of these elements, potentially leading to new proliferation concerns. In this work, a methodology for a transparent assessment of the barriers against proliferation of MAs has been developed and applied to the case of neptunium, americium, and curium separated from spent fuel from pressurized water reactors. In this methodology, openly available data and Monte Carlo simulations have been used to assess the barriers posed by a number of parameters relevant to the production of a nuclear explosive device from SNF. The evaluation shows that the properties of neptunium present low barriers to proliferation and that it should be discussed within the context of future nonproliferation treaties and possibly be placed under international safeguards. The properties of americium and curium present higher barriers to proliferation, meaning that these elements require less focus in the nonproliferation context
Screening accuracy and developmental language disorder remain stable between 2.5 and 3 years
No full textAIM: This study re-evaluated the classification accuracy of language screening. This is because the new Swedish child health programme moved this screening from 3 to 2.5 years of age. Another aim was to investigate the stability of diagnoses between these two time points. METHODS: Children were recruited consecutively during 2016-2017 from three Child Health Services in Gävle, Sweden. Forty-eight monolingual children (31 boys) and 93 bilingual children (38 boys) underwent language screening and a clinical examination by a speech and language pathologist at 2.5 years of age. They were re-examined after 6 months (at 36-38 months) for clinical diagnosis. RESULTS: Of the 48 monolingual children, 45 retained their status at both 2.5 and 3 years of age, while three no longer met the criteria for development language disorder. Among the 93 bilingual children, 87 retained their 2.5-year status at age 3, two no longer met the criteria, and four new cases were diagnosed. These differences were not statistically significant. All changes in screening parameters between 2.5 and 3 years were within the 95% Confidence Interval, indicating stable classification. CONCLUSION: Screening accuracy and language status were robust between 2.5 and 3 years, providing no support for a wait-and-see approach
Long Term Outcomes of Endovascular Repair for Blunt Traumatic Aortic Injury : A Twenty Year Multicentre Follow Up Study
No full textObjective: This retrospective, multicentre, observational study analysed patients who underwent endovascular repair for blunt traumatic aortic injury (BTAI) at four tertiary trauma referral centres over twenty years. It aimed to determine early and long term survival, to analyse aortic and device related complications, and to assess the re-intervention rate after endovascular repair for BTAI. Methods: All patients treated from 1 January 2001 to 31 October 2021 were identified using local hospital registries and two national registries: the Swedish vascular registry (Swedvasc) and Swedish trauma registry (SweTrau). Patient, treatment, and follow up data were extracted from medical records and radiology data by review of congregated imaging. The report was structured according to the STROBE checklist. Results: Ninety five patients were included: 80 were male (84%), the median age was 42 years (interquartile range [IQR] 27, 64), and median follow up time was 6.1 years (IQR 0.7, 12.4). The thirty day mortality rate was 16% (15 of 93), 40% of these were caused by traumatic brain injury and 33% by aortic related causes. Estimated overall survival was 57% (standard error 6.6) at fifteen years after index treatment. Aortic re- intervention procedures (re-stenting, coiling, or explantation) were performed in 14 of 86 patients (16%), six of whom underwent stent graft explantation. Seven of the 14 patients (50%) who underwent aortic re- intervention presented with symptoms and six of 14 had a device related complication. All complications that required aortic re-intervention were diagnosed within eighteen months of the index procedure. There was no association between injury grade and aortic re-intervention. Conclusion: Thoracic endovascular aortic repair is an effective treatment for patients with BTAI needing intervention. It carries low rates of device related complications and death, and the long term outcomes are acceptable. As all aortic complications requiring re-intervention were identified during the first two years after index treatment, with half of the patients reporting symptoms, future follow up protocols should be adjusted accordingly
Eating disorders and psychiatric comorbidity among first-year university students in Sweden : Prevalence and risk factors
No full textBackground: This study explored eating disorders (ED) prevalences, comorbidity of ED with other mental disorders, and risk factors for ED among university students. ED included binge eating disorder (BED), bulimia nervosa (BN), or other specified feeding and eating disorders (OSFED). Methods: A total of 3425 first-year university students in Sweden completed an online survey covering a range of criteria for psychiatric diagnoses, within the World Mental Health International College Student (WMH-ICS) initiative. Pearson's chi 2 -tests were used to compare algorithm-based diagnostic prevalences for eating disorders and other comorbid psychiatric disorders between three groups: students with ED with or without other comorbid psychiatric disorders (A), students with psychiatric disorders but no ED comorbidity (B), and students with no psychiatric disorders (C). Multinomial logistic regression was used to calculate between-group comparisons of odds ratios for independent risk factors, where group B served as the reference group for comparisons with groups A and C. Results: Of the total sample, 75% had at least one psychiatric disorder and 28% had at least one lifetime ED diagnosis. Students with ED (group A) reported higher prevalences for comorbid anxiety disorders, depression, suicidal behavior, and non-suicidal self-injury compared to students with psychiatric disorders but no ED (group B). Group A participants exhibited a higher risk of hazardous drinking, were more likely to have received medical treatment, and to identify as bisexual. Compared to group B, students with no psychiatric disorders (group C) were more likely to report better mental and physical health, but less likely to engage in hazardous drinking, and to have sought mental health treatment. Conclusions: A large proportion of students with ED had additional psychiatric disorders, indicating that individuals with ED suffer from multiple mental health problems. It is crucial that student health services acquire competency to offer effective ED assessment and treatment