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Circadian and Seasonal effects on resting-state fMRI
Full text linkAt temporal syklisitet er til stede i menneskelig fysiologi og kognisjon er allerede kjent. Det er imidlertid uklart i hvilken grad døgnrytmen og sesongmessige endringer påvirker den nevrale dynamikken. Denne oppgaven setter søkelys på de døgnvariasjoner og sesongvariasjoner som fanges opp av fMRI-undersøkelser i hviletilstand.
I dette arbeidet har vi brukt innsamlede data fra HCP og BETULA’s longitudinelle studier om aldring, hukommelse, og demens. I publikasjon 1 vurderte vi den daglige hjernedynamikken mellom fagene fra HCP-dataene. Funnene tyder på at mens den nevrale aktiviteten, dvs. EC, forblir stabil gjennom dagen, er parameterne som definerer BOLD-signalet, dvs. signalet som fanges opp av fMRI, imidlertid utsatt for døgnrytmepåvirkninger.
Videre har vi undersøkt hvordan tid på døgnet, i dette tilfellet tidspunkt for bildeopptak i fMRI-skanneren, påvirker lengdemålinger av hviletilstandstilkobling. Vi har brukt data fra BETULA-studien om aldring, hukommelse, og demens, i samarbeid med Umeå universitet, Sverige. Det ser ut til at klokkeslett variasjonen er tydelig i longitudinelle sammenligninger innen fag for parameterne som definerer fMRI-signalet, men ikke for EC.
Til slutt har vi vurdert sesong påvirkningene i utvalget mellom individer ved å bruke BETULA-studiedata. Vi har sammenlignet subjekter som er skannet om vinteren og om sommeren. Funnene fra denne publikasjonen antyder at begge parametere som definerer BOLD-signalet og EC er følsomme for variasjoner rundt år.
Avslutningsvis gir funnene inkludert i denne oppgaven nye bevis på daglige og sesongmessige påvirkninger på den menneskelige hjernens funksjonelle dynamikk, vurdert ved hjelp av Bayesianske analysemetoder. Vi tror at funnene våre ikke bare utfyller den eksisterende litteraturen om hviletilstand FC, men peker også på naturlig forekommende sykliske mønstre i voksne prøver som er friske og frie for patologi.Temporal cyclicity is present in human physiology and cognition. It is however unclear to what extent the circadian mechanisms and seasonal changes affect the neural dynamics. The present thesis focuses on circadian and seasonal variability that is captured by resting-state fMRI.
In this work we have used readily collected data from the HCP and BETULA longitudinal study on ageing, memory, and dementia. In publication 1 we aimed to assess the diurnal brain dynamic in between subject sample from the HCP data. The findings suggest that while the neural activity, i.e. the EC, remains stable throughout the day, the parameters that define the BOLD signal, i.e. signal that is captured by the fMRI, is however susceptible to circadian influences.
Further we have investigated how time-of-day, in this case time of image acquisition in the fMRI scanner affects longitudinal measurements of resting-state connectivity. We have used data from the BETULA study on ageing, memory, and dementia, in collaboration with the Umeå University, Sweden. It appears that the time-of-day variability is evident in the longitudinal within subject comparisons for the parameters that define the BOLD signal, however not for EC.
Finally, we have assessed the seasonal influences in the between subject sample using the BETULA study data. We have compared subjects scanned during the winter and summer. The findings from this publication suggests that both parameters that define the BOLD signal and EC are susceptible to circannual variability.
In conclusion, findings included in the present thesis offers new evidence of diurnal and seasonal influences on the human brain functional dynamics, assessed using Bayesian analysis methods. We believe that our findings not only complement the currently existing body of literature on resting-state FC, but also points to naturally occurring cyclical patterns in healthy, pathology-free adult samples.Doktorgradsavhandlin
Sense-Making Through Hybrid Talk: High-Achieving Secondary Students' Language Use during Practical Work
Full text linkThis study contributes to discussions on facilitating students' sense-making in science by analyzing the utterances of high-achieving students in dialogues during practical work and identifying characteristics of their language use and learning processes. The context of the study is a general science course at an upper secondary school in Norway. During four lessons, students from two classes conducted three exercises in electrochemistry. Data consist of video recordings from group work and whole-class dialogues, students' written explanations, and their grades in science. Using the Bakhtinian concept of hybrid constructions (i.e., utterances including both vernacular and scientific elements), we analyze dialogues about scientific concepts and possible explanations for observations made during practical work. The analysis focuses on mixed-ability groups that include one or two high-achieving students. These students' successful learning processes enable the identification of language use that is part of sense-making dialogues. We found that all students participating in dialogues used a mixture of vernacular talk, hybrid constructions, and scientific language during their learning processes. The content of scientific explanations proposed by high-achieving students initially tended to be correct but superficial. The content then became more complex and hybrid and displayed errors and inaccuracies when students discussed detailed explanatory mechanisms, and finally, it became complex and largely correct. The results indicate that the high-achieving students' use of hybrid constructions during practical work was beneficial for their learning. We discuss challenges related to creating situations in science teaching that encourage all students to engage in hybrid talk during sense-making dialogues.publishedVersio
High-resolution sediment mass-budget of the Shetland Platform during the Paleocene–Early Eocene; constraints on external forcing by uplift and climate
No full textIn the Paleocene–Early Eocene, distinct surface and stratigraphic signals recorded around Shetland have been correlated to hinterland uplift associated with the Icelandic Plume, the effects of the Paleocene–Eocene Thermal Maximum and the opening of the NE Atlantic Ocean. In this paper, we use a large dataset combining >230 000 km2 of 3D and 2D seismic data and >1700 wells to perform a high-resolution analysis of the sediment fluxes and palaeogeographical evolution around Shetland, comparing these results with an empirical–statistical model of sediment generation (BQART equation) to obtain a sediment mass-budget. In the Faroe–Shetland and Northern North Sea basins, two peaks in sediment fluxes are observed: one during the deposition of the Vaila and Lista formations (Selandian–Early Thanetian) and one associated with the Flett and Dornoch formations (close to the Paleocene–Eocene transition). Comparing these peaks with a set of independent observations suggests that both are probably controlled by uplift, with an exceptional match with various constraints on vertical motions during the Paleocene–Eocene transition. Each peak in sediment supply has distinct implications for models of geodynamic evolution. Additionally, both long-term and sharp warming during the Paleocene–Eocene transition appear not to be required to produce the observed sediment supply rates.publishedVersio
Sociolinguistics of spanish learning in Norway: Linguistic attitudes and motivation
No full textDenne studien undersøker sosiolingvistiske holdninger hos norske elever til spansk og hvordan disse påvirker språklæringen. En spørreundersøkelse blant elever ved Ås ungdomsskole og Grevlingen skole viser at holdninger til spansk struktureres i tre dimensjoner: kognitive (språkets nytteverdi og status), affektive (emosjonell tilknytning) og atferdsmessige (praktisk bruk og selvtillit). Studien fremhever behovet for tilpassede undervisningsmetoder som styrker elevenes motivasjon og læringsopplevelse.This study examines the sociolinguistic attitudes of Norwegian students towards Spanish and their influence on language learning. A survey conducted among students at Ås ungdomsskole and Grevlingen skole reveals that attitudes towards Spanish are structured into three dimensions: cognitive (perceived usefulness and status of the language), affective (emotional connection), and behavioral (practical use and confidence). The study highlights the importance of adapted teaching methods to enhance students' motivation and learning experience.Mastergradsoppgave i spansk og latinamerikastudierSPLA350MAHF-SPLAMAHF-LÆF
Towards REBOUNDLESS Circular Economy Business Models: a case of Product Service System in mobility
Full text linkThis study developed a conceptual virtual laboratory (CVL) built upon system dynamics
(SD) to for ex-ante estimation of Rebound Effects (RE) in mobility in five research stages
(RS). In RS1, the Problem was defined based on an existing conceptual framework to
identify the activation of potential rebound mechanisms in circular economy
interventions. In RS2, the conceptual constructs were translated into a hybrid stock and
flow diagram, depicting the main causal links, stocks, and flows. RS3 formalized the
dynamic hypothesis by referencing validated simulation models in Product-Service
Systems (PSS), Circular Economy (CE), and RE from the Systems Dynamics (SD)
literature. In RS4, the model underwent a validation process following established SD
literature. Finally, in RS5, 19 scenarios were analyzed to identify leverage points and
inform the selection and testing of intervention strategies for mitigating RE. The results
of the research process are discussed regarding its theoretical and practical implications
and the factors enabling the investigation itself.Masteroppgave i systemdynamikkGEO-SD350INTL-PSYKINTL-JUSINTL-MEDINTL-MNMASV-SYSDYINTL-KMDJMASV-SYSDINTL-HFINTL-S
Mechanisms behind endocrine disruption of Smoltification and seawater tolerance in Atlantic Salmon (Salmo salar) by Testosterone, 11 Keto Testosterone and 17β-Estradiol
Full text linkMaster's Thesis in BiologyBIO399MAMN-HAVSJMAMN-BI
Interpretable machine learning and feature selection in the search for dark matter
Full text linkThe field of high energy physics and the ATLAS experiment aims to discover yet unknown fundamental particles of our universe. Part of this objective is the search for dark matter. New ways of analysing high energy physics data have been introduced by deep learning, and could potentially improve the conventional analyses. However, deep learning models are complex and difficult to interpret, and their decisions should not be trusted blindly. The topic of interpretable machine learning, also called machine learning model interpretation, has become important in recent years as we try to understand the decisions of deep learning models. This thesis applies deep learning in the search for dark matter using data from the ATLAS experiment. It focuses on feature selection to optimize machine learning performance. It applies machine learning model interpretation methods to explain the decisions of deep learning models, such that their predictions can be understood, and to some degree trusted.Masteroppgave i Programvareutvikling samarbeid med HVLPROG399MAMN-PRO
The cardiac response to prolonged high-intensity physical stress: the relationship between exercise, echocardiographic parameters and Cardiac Troponin I in middle-aged athletes without obstructive coronary artery disease. The North Sea Race Endurance Exercise Study (NEEDED) 2018
Full text linkBakgrunn: Helsegevinstene forbundet med regelmessig fysisk aktivtet er udiskutable. Det er imidlertid fortsatt usikkert om svært hard og langvarig trening er gunstig for middelaldrende mosjonister, og om dette kan føre til hjerteskade. Biomarkører, som kardial troponin, og ultralydparametre kan potensielt brukes til å oppdage ugunstig hjertepåvirkning forbundet med hard fysisk aktivitet. Utfordringene er at det foreligger begrensede data hvordan disse markørene naturlig oppfører seg ved hard trening hos friske individer. I denne doktoravhandlingen er hovedformålet å få en bedre forståelse av sammenhengen mellom høyintensitets utholdenhetstrening og endringer i hjertefunksjon og struktur (ved ultralyd) og hjertetroponiner hos friske middelaldrende mosjonister uten signifikant koronarsykdom.
Metoder: Studiedeltagere ble rekruttert fra tidligere deltagelse i Nordsjørittet (91 km langt sykkelritt), og hvor signifikant koronarsykdom var utelukket. Ekkokardiografi ble utført før, umiddelbart etter, og 24 timer etter en laktat- og belastningstest (La-CPET) og ny deltagelse i Nordsjørittet i 2018. Blodprøver inkludert kardial Troponin I ble tatt før, 3- og 24 timer etter begge belastningene. Ny CT av koronarkarene ble utført etter rittet i 2018.
Resultater: I Artikkel 1 fant vi forbigående reduksjon i venstre ventrikkelfunksjon rett etter belastning. Etter arbeidet med høyest totalbelastning (rittet), fant vi økt GWW, som gjenspeiler redusert myokardial effektivitet, dette var ikke tilstede etter belastningstesten. I Artikkel II fant vi at GWW, undersøkt i hvile, var den sterkeste prediktoren for fysisk kapasitet. I Artikkel III fant vi at deltagerne med høyest kardial troponin I, etter belastning, hadde lavere myokardial deformasjon i anteroseptale segmenter av venstre ventrikkel enn deltagere med lavere troponinutslipp. Forskjellene i de anteroseptale segmentene var ikke tilstede før eller 24-timer etter belastningene.
Konklusjoner: Middelaldrende mosjonister uten signifikant koronarsykdom hadde treningsinduserte endringer i kardial struktur og funksjon forenlig med idrettshjerte. Vi fant forbigående reduksjon i hjertefunksjon, mest uttalt etter den hardeste belastningen. Høy kardial troponinrespons var assosiert med reduksjon i regional myokardfunksjon, en mulig mekanisme for troponinutslipp etter fysisk belastning, men endringene var ikke permanente. Vi fant ikke bevis for uheldige hjertepåvirkning ved hard fysisk aktivitet, selv om mosjonistene trente hardt og hvor ukentlig treningsdose overgikk gjeldende helseanbefalinger for fysisk aktivitet for den generelle befolkningen.Background: The health benefits of physical exercise are indisputable. However, the safety of middle-aged athletes engaging in vigorous physical activity and the potential for maladaptive cardiac responses remains uncertain. Biomarkers of myocardial injury, cardiac troponins, and echocardiography may be used to identify adverse cardiac responses to exercise. The challenge is limited data on the natural impact of exercise on these markers. This thesis aimed to understand the relationship between high-intensity endurance exercise and alterations in echocardiographic parameters and cardiac troponins in healthy recreational athletes without significant coronary artery disease.
Methods: Study individuals were recruited from healthy subjects, without significant coronary artery disease, who previously had participated in a 91 km mountain bike race, the North Sea Race. Echocardiography was assessed before, immediately after, and 24 hours following a lactate- and cardiopulmonary exercise test (La-CPET) and after new participation in the North Sea Race 2018. Cardiac Troponin I was collected at baseline, 3- and 24-hours following the exercises. A new CT coronary angiography was performed after the race.
Results: In Paper I, temporary reductions in left ventricular function were evident immediately following both exercises. The exercise with the highest workload (race) was associated with increased GWW (global wasted work) shortly following exercise, reflecting reduced myocardial efficiency. In Paper II, we found GWW at baseline to be the strongest independent predictor of physical fitness. In Paper III, we found that subjects with a high cardiac Troponin I (cTnI) response exhibited lower anteroseptal strain in the left ventricle shortly following both exercises compared to normal-cTnI responders. The differences in anteroseptal strain were not present before- or 24 hours following the exercises.
Conclusions: Middle-aged recreational athletes without significant coronary artery disease had findings consistent with exercise-induced cardiac remodelling at rest and evidence of temporary reductions in cardiac function shortly after exercise, most profound following the race. A high post-exercise cTnI response was associated with reduced regional myocardial function, which may provide a mechanism for exerciseinduced cTnI release, but the myocardial alterations were not permanent. In this thesis, we found no evidence of maladaptive cardiac responses to strenuous exercise, even though the middle-aged study subjects engaged in heavy exercise and a weekly exercise that surpasses current health recommendations for the general population.Doktorgradsavhandlin
Novruz: a case study of the Azerbaijani diaspora in Stavanger and their celebration in 2023
Full text linkDenne oppgaven undersøker hvordan identiteter rekonstrueres gjennom feiringen av Novruz i Stavanger, Norge. Målet er å undersøke samspillet mellom tradisjoner, tilhørigheter og innvandreropplevelser i en diasporakontekst. Basert på etnografisk feltarbeid bestående deltakende observasjoner og semi-strukturerte intervjuer utført våren 2023, utforsker studien hvordan feiringens praksiser, gjenstander og etablerte omgivelser fremmer aserbajdsjanernes følelser av tilhørighet eller identitet. Studien tar i bruk Thomas A. Tweed sin religionsteori, utviklet gjennom hans historiske og etnografiske studie av eksilkubanere som tilhører en katolsk helligdom i Miami. Ved å forske på hvordan Aserbajdsjanere feirer og forstår Novruz, samt deres motivasjoner for å feire Novruz i Stavanger, belyser studien en rekke funn knyttet til tilhørighet. Funnene indikerer at den aserbajdsjanske diasporaen i Stavanger har et ønske om å tilhøre et fellesskap som deler minner fra det gamle hjemlandet, samt ta vare på sin nedarvede kultur som samlet opprettholder deres identiteter. Disse ønskene blir oppfylt gjennom de mange krysningene og dvelingene som blir initiert av Novruz feiringen. Dette er prosesser som midlertidig transporterer Stavanger-aserbajdsjanere lokasjons– og tidsmessig til deres tidligere hjemland. Samtidig blir de orientert i nåtiden gjennom omgivelsene som skaper følelsen av et hjem og som gir aserbajdsjanerne muligheten til å videreføre sin kulturarv til nye generasjoner.This thesis investigates the ways in which identities are reconstructed through the celebration of Novruz in Stavanger, Norway. The aim is to examine the interplay between traditions, belongings and immigrant experiences in a diaspora context. Based on brief ethnographic fieldwork consisting of participant observation and semi-structured interviews conducted in the spring 2023, this study explores how celebrational practices, artifacts and spaces foster Azerbaijanis’ senses of belonging or identity. To analyze my findings, I rely on Thomas A. Tweed’s theory of religion, developed through his historical and ethnographic study of Cuban exiles at a Catholic Shrine in Miami. I propose to examine Azerbaijanis’ expressed desire for belonging through a study of how they celebrate Novruz, how they understand Novruz, and their motivations for celebrating Novruz in Stavanger. My findings indicate that the Azerbaijani diaspora in Stavanger has a desire to belong to a community that share memories of the old homeland, and to maintain their inherited culture, that contribute to the sustenance of their identities. These two desires are temporarily fulfilled through the many crossings and dwellings the celebration initiates – processes that transport Stavanger-Azerbaijanis locatively and temporally to their previous homeland and situate them in the present by creating a space in which they feel at home and pass on Azerbaijani heritage to new generations.Religionsvitenskap mastergradsoppgaveRELV350MAHF-RELVMAHF-LÆH
Age-related variations in mental health and wellbeing during the first wave of the COVID-19 pandemic: a multi-country survey analysis
Full text linkBackground: The COVID-19 pandemic substantially impacted mental health. This study explored age-related differences in the mental health and wellbeing of participants during the initial wave of the COVID-19 pandemic.
Methods: Secondary analyses of data from 21,106 participants collected between July and December 2020 across 152 countries was conducted. Multivariable logistic regression models were used to determine the relationship between the dependent variables and age after accounting for potential confounders. The dependent variables examined were emotional distress, social isolation, sleep pattern changes, sexual activity changes, financial security, housing and food insecurity, changes in family relationships, memory complaints, and post-traumatic stress syndrome (PTSS). Age groups were considered: young adults (18–24), adults (25–49), and older individuals (≥50). The confounding variables were sociodemographic variables namely: sex (male or female), marital status (single or has had a relationship), employment status (employed, unemployed, student, or retiree), educational status (none, primary, secondary, or college/university), country of residence income (low-income countries, lower-middle-income countries, upper-middle-income countries, and high-income countries) and pandemic stringency index indicating the comprehensiveness of pandemic policies adopted at country level.
Results: Of the 21,106 participants, 12,807 (60.7%) were aged 25–49. Compared to those over 50, 18–24-year-olds had significantly higher odds of increased sexual activity (AOR: 4.41), housing insecurity (AOR: 1.73), and PTSD (AOR: 3.22), but lower odds of social isolation (AOR: 0.66), food insecurity (AOR: 0.85), and memory complaints (AOR: 0.53). Similarly, 25–49-year-olds had higher odds of increased sexual activity (AOR: 2.65), housing insecurity (AOR: 2.28), food insecurity (AOR: 1.14), worsened family relationships (AOR: 1.15), and PTSD (AOR: 2.24), but lower odds of social isolation (AOR: 0.84), sleep disturbances (AOR: 0.82), and memory complaints (AOR: 0.81). Emotional distress and financial insecurity did not differ significantly across age groups.
Conclusion: The study highlights age-specific variations in mental health challenges during the pandemic. The nuanced impact of age on mental wellbeing emphasizes the need for targeted interventions. Future research should explore the interplay between age, pandemic-related factors, and specific mental health outcomes to inform tailored support mechanisms for diverse age groups.publishedVersio