39449 research outputs found
Sort by
Experimental hypothermia by cold air: a randomized, double-blind, placebo-controlled crossover trial
No full textBackground: Accidental hypothermia is associated with high morbidity and mortality. Research on treatment strategies for accidental hypothermia is complicated by the low incidence and heterogeneous patient population. We have developed a new method for clinical trials of experimental hypothermia, to enable further studies of active rewarming. If cold ambient air is effective as a cooling method, this would mimic the most frequent clinical setting of hypothermic patients and provide a feasible cooling method for field studies. We aimed to induce mild hypothermia in healthy volunteers by exposure to cold ambient air, and tested the hypothesis that drug-induced suppression of endogenous thermoregulation would be required.
Methods: In a randomized, double-blind, crossover design, 15 healthy volunteers wearing wet clothes were put in a windy climate chamber set to 5 °C. Each participant completed the experimental procedure twice, once receiving active drugs (meperidine and buspirone) and once receiving placebo. The experiments were separated by a one-week wash-out period. Primary outcome was core temperature at termination, defined as 3 h of exposure or 35 °C. The between-groups difference was assessed using analysis of covariance (ANCOVA) with left censoring (Tobit model) and individual random intercept. Secondary outcomes were trajectory of core temperature and reduction of shivering.
Results: At termination, the active drug vs placebo group differed in temperature by 1.4 °C. With adjustment for the removal of participants reaching 35 °C, the estimated mean difference was 1.7 °C (1.4–2.0, p < 0.001). Shivering was effectively reduced, but not completely inhibited by the drug regimen, and core temperature declined at a rate of − 0.82 °C per hour.
Conclusion: The novel protocol utilizing cold air as a cooling method and drug-induced suppression of endogenous thermoregulation, is effective and enables future research projects. We have provided suggestions for minor alterations.publishedVersio
Observations on TETRA Encryption Algorithm TEA-3
No full textWe present a number of observations on TEA-3, a stream cipher used in TETRA radio networks that was kept secret until recently. While the same also holds for the six other TETRA encryption algorithms, we pick TEA-3 to start with, as (i) it is not obviously weakened as TEA-{1,4,7} but (ii) in contrast to TEA-2 it is approved for extra-European emergency service, and (iii) as already noted by [MBW23] the TEA-3 design surprisingly contains a non-bijective S-box. Most importantly, we show that the 80-bit non-linear feedback shift register operating on the key decomposes into a cascade of two 40-bit registers. Although this hints at an intentional weakness at first glance, we are not able to lift our results to a practical attack. Other than that, we show how the balanced non-linear feedback functions used in the state register of TEA-3 can be constructed.publishedVersio
Polarized Recruitment of Secretory Vesicles in the Choanoflagellate Salpingoeca rosetta: Insights into the Origin of Neurosecretion
No full textEvolusjonen av strengt regulert sekresjon, som i nevroner, markerte et vendepunkt for opprinnelsen og diversifiseringen av ulike celletyper i dyreriket. Spesialiserte regulerte sekretoriske celler brukes i viktige organismeprosesser og -reaksjonsveier, slik som immunitet og forsvar, metabolisme og vekst, og informasjonsbehandling. De evolusjonære opprinnelsene til regulert sekresjon er midlertid i stor grad ukjente. I denne avhandlingen brukte vi choanoflagellater - søstergruppen til metazoer - for å beskrive lokaliseringen og potensielle funksjoner til nøkkelaktørene involvert i vesikkeltransport, -rekruttering og -festing. For dette tilpasset vi nylig etablerte molekylærbiologiske teknikker, inkludert transient transfeksjon og CRISPR/Cas9-mediert genomredigering. Vi brukte volum-elektronmikroskopi og 3D-organelle-rekonstruksjon for å beskrive knockout-fenotyper. Proteinet Unc13 er et vesikkelfestings- og rekrutteringsprotein i metazoiske regulerte sekretoriske celler, slik som mastceller, nøytrofiler, insulinutskillende beta-celler i bukspyttkjertelen, og i kjemiske pre-synaptiske nevroner. De viktigste proteindomenene som fremhever metazoisk homolog av dette proteinet er bevart i choanoflagellater, og her viser vi at dette proteinet fungerer i apikal vesikkelrekruttering og -fusjon. Knockout av SrUnc13-1 viser defekter i flagelldannelse og celledeling. SPIRE er et aktin nukleatorprotein som, i metazoer, muliggjør aktinnukleering for apikal transport av vesikler via interaksjonen med Myosin-5 (MYO5) motorprotein og Rab3 vesikkelmarkørprotein. Transient transfeksjon av S. rosetta homologer SrSPIRE, SrMYO5 og SrRab8 (stamfarprotein til metazoisk-spesifikk Rab3) avslører apikal lokalisering av deres respektive punkter. Denne avhandlingen fremhever den bevarte reguleringen i apikal vesikkeltransport, -rekruttering og -fusjon i metazoer og choanoflagellater. Regulert sekresjon slik vi ser den i komplekse metazoiske celletyper dateres minst tilbaketil den siste felles stamfaren til choanoflagellater og metazoer.The evolution of tightly regulated secretion, such as in neurons, marked a turning point for the origins and diversification of cell types in the animal kingdom. Specialized regulated secretory cells are employed in key organismal processes and pathways, such as in immunity and defense, metabolism and growth, and information processing. However, the evolutionary origin of regulated secretion is largely unknown. In this thesis, we used choanoflagellates – the sister group of metazoans – to describe the localization and potential functions of the key players involved in vesicle transport, recruitment, and tethering. For this, we adopted recently established techniques, including transient transfection and CRISPR/Cas9-mediated genome editing. We used volume electron microscopy and 3D organelle reconstruction to describe knockout phenotypes. Protein Uncoordinated-13 (Unc13) is a vesicle tethering and recruitment protein in metazoan-regulated secretory cells, such as the mast cells, neutrophils, insulin-secreting pancreatic beta-cells, and in chemical pre-synapses in neurons. The major domains that highlight the metazoan homolog of this protein are conserved in choanoflagellates, and here we show that this protein functions in apical vesicle recruitment and fusion. Knocking out SrUnc13-1 shows defects in flagellum formation and cell division. Protein SPIRE homolog (in short, SPIRE), is an actin nucleator protein that, in metazoans, enables actin nucleation for apical transport of vesicles via the interaction with Myosin-5 (MYO5) motor protein and Rab3 vesicle marker protein. Transient transfection of S. rosetta homologs SrSPIRE, SrMYO5, and SrRab8 (ancestral protein of metazoan-specific Rab3) reveals apical localization of their respective punctae. Overall, this thesis highlights the conserved regulation in apical vesicle transport, recruitment, and fusion in metazoans and choanoflagellates.Doktorgradsavhandlin
A scoping review on early childhood caries and inequalities using the Sustainable Development Goal 10 framework
No full textBackground
Social inequalities contribute to health disparities. This study aimed to map evidence on early childhood caries (ECC) related to the United Nations' Sustainable Development Goal 10 (SDG 10).
Methods
A scoping review was conducted in May 2024 following the PRISMA-ScR guidelines. A literature search was performed in PubMed, Web of Science, and CINAHL for studies published in English and addressing population level social inequalities. Studies measuring individual level of social inequalities were excluded as they were covered by other SDGs. However, studies incorporating individual measures as additional measures of population level social inequality were included. Retrieved papers were summarized, inductively analysed and a conceptual framework linking SDG 10 was developed.
Results
Of 452 studies retrieved, 42 met the inclusion criteria. Studies measured inequality among groups (deprivation, family income, indigenous communities, ethnicity, minority status) [14 studies], institutions (type of school, nursery or school facility, school poverty index, public primary health care units) [five studies], and inequality in communities (neighbourhood socio-economic status, Human Development Index, employment rate, income inequality, sanitary sewer and water supply, residents/household ratio, urban vs rural vs remote rural, accessibility index, location index, the slope index of inequality) [24 studies]. These levels of social inequalities were linked to higher prevalence of ECC; social and economic policies contributed to widening inequalities in ECC severity; and although effective interventions targeted at at-risk populations could reduce dental health disparities, study interventions differed by deprivation status. Six studies (14.3%) addressed SDG 10.1, 33 (78.6%) addressed SDG 10.2, 11 (26.2%) addressed SDG 10.3, and three (7.1%) addressed SDG 10.4. Fourteen studies (33.3%) addressed a combination of SDGs. The conceptual framework highlights the role of structural inequalities stemming from the cumulative impact of institutional decisions and systemic inequalities.
Conclusion
This scoping review underscores the profound influence of social inequality on ECC through interactions between multi-level factors. Further research is needed to explore the links between ECC and other SDG 10 targets, especially in low- and lower-middle-income countries.publishedVersio
Hydrocarbon seepage in the Southern Norwegian North Sea - An evaluation of the source-to-seep system within the “dry belt”
No full textThis thesis have investigated the origins of emerged oil slicks within the "dry belt of Norway." Four candidates are presented as potential carrier beds, connceting the Central Graben to Block 9/12. Additionally, vertical migration pathways from deeper buried source rocks of Paleozoic age are defined and visualized. This study concludes that the Ekofisk Fm is the most plausible carrier bed from the Central Graben, and that vertical migration along salt-induced crestal faults provide connections between identified shallow accumulations and carrier beds. Furthermore, petroleum of Paleozoic age is proposed to be present in sub-salt traps, with further migration through the thinner parts of the Zechstein Salt post-halokinesis.Masteroppgave i geovitenskapGEOV399MAMN-GEO
Forurensningsmyndighetens adgang til å fremme hensynet til effektiv energiutnyttelse etter forurensningsloven
Full text linkMasteroppgaveJUS399MAJUR-2MAJU
A systematic method to integrate co-produced causal loop diagrams based on feedback stories
Full text linkWithin participatory systems dynamics, more practitioners are compiling co-produced causal loop diagrams (CLDs) to analyse and report workshop outputs. Though not formalized, existing documented techniques have been limited to analyses of representations in single-group diagrams predicated on, at times, untraceable subjective judgements. This paper addresses the need for a systematic method to guide and justify the subjective decisions made in the integration process. We propose a multistep, three-stage process that synthesizes feedback stories from representations in diagrams (i.e. what is represented) and transcripts of the participatory process (i.e. what is said). This approach enables practitioners to report the interpretive scheme through which qualitative data are analysed and, thus, support the subjective decisions they made during the integration process. Using a case study, we demonstrate the application of this method and its potential for narrowing the semantic distance between participants, practitioners and external audience for interpreting and analysing an integrated diagram.publishedVersio
Screening of tumor suppressor microRNAs to boost the killing efficacy of suicide gene therapy for brain cancer treatment
Full text linkMaster's Thesis in Biomedical SciencesBMED395MAMD-MEDB
Fragmenting forest governance: Land tenure and the REDD+ paradox in Kigoma pilot project, Tanzania
Full text linkForest economists and governance scholars disagreed in early REDD + literature over the potentially recentralizing effects of the performance-based global forest carbon mitigation mechanism. Economists argued conditional payments for measurable forest protection would incentivize sustainable forest management, despite institutional challenges. Critics viewed this assumption as too rationalistic. Proponents of participatory forest management in Tanzania argued REDD + funding was wasted creating new pilot projects from scratch, instead of upscaling existing forestry programmes. This article uses an in-depth ethnographic case study of rent and accountability relations in a failed REDD + test pilot project site, showing the complexity of trans-local governance arrangements. Fragmented actors compete over diverse interests, overlapping spheres of authority and tenure regimes. Empirically, it examines how project implementation with unclear land tenure exacerbated boundary conflict and insecurity, tracing upwards accountability relations including stigmatizing elected village leaders, overriding of decisions made within a village assembly meeting by district level authorities, using strategies of forum shopping and evoking the politics of scale via ward councils. This highlights the need for future forest policies to prioritize questions of land tenure, political accountability and the context-specific interactions of forest users before blueprint technical solutions that involve biophysical measurement of trees to estimate forest carbon densities.publishedVersio
Machine Truth : The Construction and Contestation of Epistemic Authority in Automated Fact-checking
Full text linkDenne doktorgradsavhandlingen utforsker automatisering av faktasjekking—en praksis som systematisk vurderer sannhetsgehalten i informasjonspåstander publisert i media. Ideen om å innlemme kunstig intelligens (KI) og praksiser for informasjonsverifisering i nyhetsarbeidet oppsto blant programmerere og faktasjekkere, og var en respons på det økende problemet med desinformasjon og det økende presset på journalister om å verifisere overveldende mengder informasjon. Noen konseptualiserer denne tilstanden som en epistemisk krise. Siden slutten av 2010-tallet har det blitt tatt flere initiativer for å designe verktøyer som kan sjekke medierte fakta ved bruk av KI-algoritmer. Automatiserte verktøy for faktasjekking og faktatjenester blir ofte fremstilt som om de er i stand til å produsere det jeg kaller «maskinsannhet»—informasjonstype produsert av algoritmiske teknologier og kommunisert som epistemisk autoritative utsagn om virkeligheten. Men etter nesten ti år, kan ikke automatiserte verktøy for faktasjekking sjekke fakta automatisk, eller de gjør det med betydelige mangler og begrensninger. Dermed er deres epistemiske autoritet fortsatt omstridt. Denne doktorgradsstudien undersøker den korte og brokete historien om automatisert faktasjekking.
I denne avhandlingen blir automatisert faktasjekking studert som en sosioteknisk innovasjon—en utvikling som introduserer algoritmisk logikk i arbeidet med faktasjekking. Jeg tar utgangspunkt i de tverrfaglige røttene til automatisert faktasjekking og utvikler et teoretisk rammeverk basert på konsepter fra sosial epistemologi, vitenskaps- og teknologistudier (STS) og innovasjonsstudier. Ved å drøfte den epistemiske praksisen faktasjekking sammen med automatiserte teknologier, svarer avhandlingen på forskningsspørsmålet: Hvordan konstruerer og bestrider forsknings- og praksisfellesskapet den epistemiske autoriteten til automatisert faktasjekking som en sosioteknisk innovasjon?
Forskningsspørsmålet blir besvart gjennom funn fra tre kvalitative studier som dette doktorgradsprosjektet består av i tillegg til kappen. Artikkel 1 er en kartleggingsstudie av akademisk forskning på automatisert faktasjekking, og den baserer seg på en tematisk og disiplinorientert analyse. Studien utforsker den forståelsen informatikk og journalistikkforskning har av fenomenet automatisk faktasjekking, og introduserer en tverrfaglig definisjon av automatisk faktasjekking. Artikkel 2 undersøker de strategiske innrammingene nye oppstartsselskaper gjør av sine automatiserte verifiseringsverktøy og -tjenester. Studien analyserer selskapenes primære kommunikasjonskanaler, nemlig deres nettsider. Artikkel 3 er en teknografisk casestudie av et oppstartsselskap og dets forsøk på å skape et automatisert verktøy for faktasjekking eller en KI-redaktør. Ved hjelp av intervjuer med ansatte, dokumentanalyser og teknografiske notater identifiserer studien de utfordringene seslskapet møtte under utviklingen av sitt automatiserte verktøy for faktasjekking.
Basert på funnene i de tre artiklene, undersøker kappen den teknologiske og sosiale konstruksjonen av automatisert faktasjekking innen forsknings- og praksisfellesskapene. I kappen gjør jeg en sosioteknisk undersøkelse av de epistemiske autoriteten til disse verktøyene og tjenestene. Forsknings- og praksisfellesskapene ser på automatisert faktasjekking enten som et teknologisk verktøy eller som en sosial praksis med mål om å forbedre faktasjekkingen. Jeg problematiserer automatisert faktasjekking som en epistemisk autoritet drevet frem av motstridende paradigmer innen informatikk og journalistikk. Til tross for det begrensede gjennomslaget for automatiserte verktøy for faktasjekking, har oppstartsbedrifter etablert seg innen nyhetsøkosystemer ved å hevde teknologisk og journalistisk ekspertise, og tilbyr automatiserte løsninger for å øke tilliten til nyheter.
Dette er en av de første doktorgradsavhandlingene som undersøker automatisert faktasjekking med et kvalitativt perspektiv, og den bidrar med en tverrfaglig definisjon av automatisert faktasjekking. Dette er "et sosioteknisk verktøy og en praksis som søker autonomi i arbeidet med informasjonsverifisering med begrenset epistemisk autoritet. Det innebærer å behandle data for å oversette journalistisk kunnskap til semantiske enheter – påstander, bevis og forklaringer – og beregne kompatibiliteten mellom de semantiske enhetene for å styrke og akselerere menneskets evne til å verifisere informasjon." Denne definisjonen understreker viktigheten av tverrfaglige perspektiver i forskning på og utvikling av automatiserte verktøy for faktasjekking som er ment å håndtere desinformasjon i nyhetsøkosystemer.This doctoral thesis explores the automation of ex-post fact-checking—a practice of systematically assessing the veracity of information claims published in the media. The idea of integrating Artificial Intelligence (AI) technologies and information verification practices emerged among computer scientists and fact-checkers in response to the growing disinformation problem and the accompanying pressure on news workers to verify overwhelming amounts of information. Media and information scholars conceptualize this condition as an epistemic crisis. Since the late 2010s, several initiatives have been launched to design tools suitable to check mediated facts using AI algorithms. Automated fact-checking tools and services are often communicated as capable of producing what I call “machine truth”—information produced by algorithmic intermediaries communicated as epistemically authoritative assertions about reality. However, after almost a decade-long effort, automated fact-checking tools do not actually check facts automatically, or they do so with substantial flaws and limitations. Thus, their epistemic authority is still questionable. This doctoral study explores the short yet insightful and scantly researched history of this effort.
In this thesis, automated fact-checking is studied as a sociotechnical innovation— an endeavor that introduces algorithmic logic to ex-post fact-checking. Emphasizing the interdisciplinary roots of automated fact-checking, I draw on a theoretical framework built on concepts from social epistemology, Science and Technology Studies (STS), and innovation studies. I tie together fact-checking as an epistemic practice with automation technologies as a sociotechnical innovation and answer the research question: How do research and practice communities construct and contest the epistemic authority of automated fact-checking as a sociotechnical innovation?
The research question is addressed through findings from three qualitative studies, corresponding to three articles written as a part of this PhD project. Article 1 is a scoping literature review offering a disciplinary and thematic analysis of academic research about automated fact-checking. The study explores the computational and journalistic understanding of the phenomenon and offers an interdisciplinary definition of automated fact-checking. Article 2 explores the strategic framing of automated information verification tools and services by news startups. The study qualitatively analyses strategic framing practices via news startup websites as their primary communication channel. Article 3 is a technographic case study of a news startup and its attempt to create an automated fact-checking tool or AI editor. Interviews with company-related stakeholders, along with document analysis and technographic notes, helped me to identify the challenges that this particular automated fact-checking startup faced.
Based on the findings of the three articles, the framing introduction examines the technological and social construction of automated fact-checking according to perspectives from research and practice communities. An examination of the sociotechnical contestation of the epistemic authority of such tools and services follows this. Findings reveal that the research and practice communities view automated fact-checking as either a technological tool or a social practice aimed at enhancing ex-post fact-checking. The study examines the contestation of automated fact-checking as driven by conflicting paradigms in computer science and journalism. Despite the limited potential of automated fact-checking tools and services, news startups establish themselves within news ecosystems by asserting both technological and journalistic expertise and presenting their technologies as automated solutions to restore trust in a news ecosystem affected by an epistemic crisis.
To conclude, as one of the first qualitative doctoral studies of automated fact-checking, the main contribution of this thesis is to advance an interdisciplinary understanding of automated fact-checking. It is “a sociotechnical tool and a practice that seeks autonomy in information verification tasks with limited epistemic authority. Such tasks are processing data to translate journalistic knowledge into semantic units – claim, evidence, and resolution/explanation - and calculating the compatibility of semantic units with each other to enhance and speed up the human ability to verify information.” This definition underlines the importance of involving interdisciplinary perspectives when studying and developing automated fact-checking tools and services as epistemic intermediaries that potentially can tackle the disinformation surge in news ecosystems.Doktorgradsavhandlin