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From aquaculture sludge to microalgae : Experimental analysis and value chain assessment
Get PDFDenne studien evaluerer hvorvidt mikroalgedyrking og anaerob nedbrytning er biologisk og teknologisk egnet som avfallsbehandling av fiskeslam fra akvakultur. Videre ble denne verdikjedens miljøkonsekvenser, grunnleggende økonomiske påvirkninger og logistiske aspekter vurdert. Potensialet for bioremediering av gjenværende næringsstoffer i avløpsvann fra resirkulerende akvakultursystem (RAS), gjennom dyrking av mikroalger, ble demonstrert. Næringsstoffnivåene i RAS-avløpsvannet ligger vanligvis under de konsentrasjonene som er nødvendige for å opprettholde dyrking av mikroalgekulturer med høy tetthet. Denne utfordringen ble møtt ved å koble den hydrauliske oppholdstiden av RAS-mediet fra oppholdstiden for algene i reaktoren, enten gjennom immobilisering av mikroalger ved hjelp av biofilmdyrking (Paper I) eller ved å bruke membranfiltrering til perfusjonsdyrking (Paper II). I eksperimentene med biofilmdyrking ble en tolags biofilmreaktor testet og forbedret for å kunne tåle saltvann. Fem ulike bærematerialer ble sammenlignet for å finne det som hadde best festeevne for mikroalger. Mikroalgevekst ble testet på alle typer RAS-avløpsvann (ferskvann, brakkvann og saltvann), og resultatene viste at det var mulig å oppnå fullstendig opptak av nitrat (N) og fosfat (P) fra avløpsvannet sammen med god biomasseproduktivitet (Chlorella i ferskvanns RAS-medium: 4.25 g m−2 d−1; Phaeodactylum i brakkvann RAS-medium: 15.28 g m−2 d−1; i saltvanns RAS-medium: 4.35 g m−2 d−1).
Næringsopptak fra RAS-avløpsvann og mikroalgenes biomasseproduktivitet ble også testet i 25 L rørformede fotobioreaktorer. Kontinuerlig dyrking på RAS-medium tilsatt ekstra N-gjødsel ble sammenlignet med perfusjonsdyrking ved hjelp av membranfiltrering (Paper II). Begge dyrkingsmåtene resulterte i opptak av næringsstoffer fra RAS-vannet og jevnt høye biomassetettheter (opptil 3.88 g L 1). Livssyklusanalyse (LCA) ble brukt til å evaluere den miljømessige bærekraften til de to dyrkingsmetodene i en produksjonsskala på 1 hektar. Selv om perfusjonsdyrking senker potensialet for negative miljøpåvirkninger fra avfallsvann medfører det høyere driftskostnader (6 %) og en betydelig økning i kapitalutgifter (opptil 60 %) på grunn av ekstra utstyrs- og energibehov.
For å evaluere potensialet for energigjenvinning gjennom anaerob nedbryting av fiskeslam, ble det samlet inn eksperimentelle data fra prosjektpartnerne. Den flytende bioresten fra forråtnelsesprosessen ble også testet som gjødsel for dyrking av mikroalger. Den integrerte verdikjeden, som kombinerer avfallsstrømmer fra akvakultur til mikroalgedyrking og til næringsstoff- og energigjenvinning ved anaerob nedbryting, ble studert for å forstå massestrømmer og miljømessig bærekraft i et oppskalert produksjonsscenario (Paper III). Et basisscenario for fiskeslambehandling, der 50 % av fiskeslammet tørkes og sendes til Danmark for biogassproduksjon, ble sammenlignet med tre alternative scenarier. En LCA av disse verdikjedene viste at viktige faktorer for miljømessig bærekraft var geografiske forskjeller i sammensetningen av nasjonale elektrisitetskilder, energiforbruk ved tørking av fiskeslam og mikroalgedyrking, samt effektiviteten i biomasseproduksjon. Gjenværende utfordringer er å avklare viktige regulatoriske aspekter, som hvorvidt mat- eller fôrprodukter fra mikroalger dyrket på avløpsvann fra RAS vil kunne godkjennes, eller hvordan biogjødsel fra forråtningsprosessen, som inneholder tungmetaller, skal klassifiseres.This study evaluates the biological and technological suitability of an aquaculture fish sludge waste treatment, using microalgae cultivation and anaerobic digestion (AD). The value chain was further assessed in terms of environmental impacts, preliminary economic as well as logistical aspects. The potential for bioremediation of leftover nutrients from recirculating aquaculture system (RAS) wastewater through microalgae cultivation was demonstrated. Nutrient levels of the RAS effluent water are usually below the concentrations which are necessary to maintain a high-density microalgae culture. This challenge was approached by uncoupling the hydraulic retention time (HRT) of the RAS medium and the HRT of the algae in the reactor, either through immobilization during microalgae biofilm cultivation (Paper I) or perfusion cultivation through membrane filtration (Paper II). In the biofilm cultivation experiments, a twinlayer biofilm reactor was tested and improved for its saltwater suitability. Five different carrier materials were compared to determine the best material for microalgae attachment and durability. Microalgae growth was tested on all RAS effluent water types (fresh-, brackish, and salt water), demonstrating the possibility of a complete uptake of nitrate (N) and phosphate (P) from RAS effluent water while obtaining good biomass productivity (Chlorella on freshwater RAS medium: 4.25 g m-2 d-1; Phaeodactylum on brackish RAS medium: 15.28 g m-2 d-1; on saltwater RAS medium: 4.35 g m-2 d-1).
The nutrient uptake from RAS effluent water and microalgal biomass productivity was also tested in 25 L tubular photobioreactors. Continuous cultivation on RAS medium with additional N fertilizer and perfusion cultivation through membrane filtration were compared (Paper II). Nutrient remediation from the RAS effluent water, as well as stable high biomass densities were achieved in both cultivation modes (up to 3.88 g L-1). A life cycle assessment (LCA) was used to evaluate the two cultivation methods for environmental sustainability on a 1-ha scale. While perfusion cultivation has a lower environmental impact potential for low-nutrient wastewater, it entails higher operational costs (6%) and significantly increased capital expenses (up to 60 %) due to additional equipment and energy demands.
For the evaluation of the energy recovery potential though anaerobic digestion on fish sludge, data was collected from project partners. The liquid digestate from the AD process was also tested as a fertilizer for microalgae cultivation. The integrated value chain from aquaculture waste streams, through microalgae cultivation and anaerobic digestion for nutrient and energy recovery, was then assessed in terms of mass-flows, economic feasibility and environmental sustainability of an upscaled production scenario (Paper III). A baseline scenario (where 50% of the fish sludge is dried and shipped to Denmark for biogas production) was compared to three alternative sludge treatment scenarios. An LCA revealed that geographical differences in the national electricity mix, the energy consumption of sludge drying and microalgae cultivation, and the biogas efficiency of the AD process were major hotspots in the environmental sustainability and economic feasibility of these value chains. Important remaining challenges are regulatory factors such as the use of microalgae grown on RAS wastewater for products other than non-food/feed materials and the classification of the biofertilizer derived from the AD process (mainly in terms of heavy metal content).Doktorgradsavhandlin
Historiebruk blant tradwives på sosiale medier: En analyse av innlegg publisert på Instagram mellom 2020 og 2025.
Get PDFThis master’s thesis examines how women who identify as tradwives, use history in their Instagram posts to legitimize their messages and construct identity and community. Furthermore, the thesis highlights how this use of history reflects ideological and cultural tensions. Methodologically, the study is based on qualitative analyses of posts from five selected Instagram accounts, in the period between 2020 and 2025. The analysis is twofold, employing a contextual approach in one part and an intertextual approach in the other. Jörn Rüsen’s typology of historical narratives is used as the theoretical framework.
The main findings show that tradwife profiles selectively use history to promote traditional gender roles and conservative values. This is often expressed through nostalgic, aesthetic, and religious depictions of earlier historical periods. In such representations, history is used as an ideological tool to create continuity and authority. The study identifies three main categories of tradwives - nostalgic, critical, activist - who each use history in different ways to confirm or challenge contemporary norms.
The conclusion is that the use of history among tradwives represents an example of ideological and at times misleading use of the past. The study shows how social media serves as an arena for the dissemination of history and ideological mobilization, and it contributes to a greater understanding of how the past is used in digital spaces to promote cultural and political agendas.Historie mastergradsoppgaveHIS350MAHF-LÆHRMAHF-HI
Bevisføring i møte med kunstig intelligens: Er domstolene rustet til å håndtere de nye bevisene?
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Når blir en stat part i en væpnet konflikt eller krig gjennom å yte militær bistand til en av partene i konflikten? Om grensene for partsstatus gjennom militær bistand.
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Flyselskapers ansvar overfor passasjerer ved kanselleringer og lange forsinkelser - Særlig om rekkevidden av ansvarsfritaket ved «ekstraordinære omstendigheter» i EU-forordning (EF) 261/2004 artikkel 5 nr. 3
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Screening and Functional Evaluation of Novel Ligands Targeting Cysteine Sulfinic Acid Decarboxylase
Get PDFCysteinsulfinsyre-dekarboksylase (CSAD) er et enzym som inngår i biosyntesen av taurin hos pattedyr. Den tilhører foldetype I-superfamilien av pyridoksalfosfat (PLP)-avhengige enzymer. Selv om taurin ikke regnes som en essensiell aminosyre, er den en av de mest forekommende frie aminosyrene i kroppen. Den spiller en sentral rolle i hjernen, ryggmargen, muskelvev, netthinnen, leukocytter, og flere andre organer. Pattedyr er avhengige av å ha tilstrekkelig mengder med taurin i kroppen, og tilskudd gjennom kosten er nødvendig for individer med taurinmangel. Lave taurinnivåer er assosiert med nyresvikt, utviklingsforstyrrelser, kardiomyopati, og nevrodegenerative sykdommer som Parkinsons-, Alzheimers-, og Huntingtons sykdom. Til tross for taurins uomtvistelige viktighet, er mengden forskning på dens biosyntese begrenset. I denne metabolske veien omdanner CSAD cystein sulfinsyre (CSA) til hypotaurin, som deretter oksideres til taurin ved hjelp av et flavinholdig hypotaurin-monooksygenase. Identifikasjon av nye forbindelser som kan aktivere, stabilisere, eller hemme CSAD kan ha betydelig innvirkning på taurinsyntesen. En slik modulering kan legge til rette for fremskritt innen utvikling av nye terapeutiske metoder for behandling av taurinrelaterte nevrologiske lidelser. Basert på dette, har dette prosjektet som formål å uttrykke og rense mus-CSAD, og samtidig undersøke mulige forbindelser som kan binde til proteinet. For å oppnå dette ble 50 forbindelser, tidligere identifisert av tidligere medlemmer av laboratoriet, screenet ved hjelp av en fluorescensbasert termisk stabilitetsanalyse. Videre ble aktivitetsanalyser gjennomført ved bruk av to forskjellige kvantitative metoder, og treffene ble deretter enzymatisk testet med tanke på CSAD. I tillegg ble effekten av karbidopa og oxymatrine på den enzymatiske aktiviteten på CSAD evaluert. Totalt ble åtte forbindelser observert å påvirke den enzymatiske aktiviteten med mer enn 20 %, og disse ble videre undersøkt gjennom dose-respons forsøk for å bestemme deres inhibitoriske potens. Etakrynsyre (2-[2,3-diklor-4-(2-metylidenbutanoyl)fenoksy]eddiksyre) og PCIPYR-0303 ((5-kloro-1-cyklopropylmetyl-6-okso-1,6-dihydro-pyridazin-4-yl)-pyridin-2-yl-acetonitril) ble observert å ha den mest konsistente og potente inhiberingen på CSAD. Steady-state kinetiske studier ble utført for disse to forbindelsene for å undersøke deres bindingsmekanismer nærmere. Foreløpige resultat viste at etakrinsyre utviste ukompetitiv inhiberingskinetikk, mens en blandet type inhibering ble observert for PCIPYR-0303.Cysteine Sulfinic Acid Decarboxylase (CSAD) is an enzyme involved in taurine biosynthesis in mammals and belongs to the fold type I superfamily of pyridoxal phosphate (PLP)-dependent enzymes. Although taurine is not an essential amino acid, it is one of the most abundant free amino acids in the body. It plays a crucial role in the brain, spinal cord, muscle tissue, retina, leukocytes, and other organs. Mammals depend on adequate levels of taurine in the body, and those deficient in this amino acid must obtain it through dietary supplementation. Low taurine levels have been associated with renal failure, developmental abnormalities, cardiomyopathy, and neurodegenerative diseases such as Parkinson's disease, Alzheimer's disease, and Huntington's disease. Despite taurine's undisputable importance, research on its biosynthesis remains limited. In this pathway, CSAD converts cysteine sulfinic acid (CSA) to hypotaurine, which is later oxidized to taurine by a flavin-containing hypotaurine monooxygenase. Identifying novel compounds that activate, stabilize, or inhibit CSAD could significantly influence taurine production. Such modulation could enable advancements in new therapeutic strategies for managing taurine-related neurological disorders. Based on this, the present project aimed to express and purify mouse CSAD and investigate potential compounds capable of binding. To achieve this, a library of 50 compounds previously identified by former lab members was screened using a fluorescence-based thermal stability assay. Next, activity assays were performed using two different quantitative methods, and the selected hits were enzymatically tested against CSAD. In addition, the impact of carbidopa and oxymatrine on the enzymatic activity of CSAD was evaluated. This screening identified eight compounds that exhibited an effect on the enzymatic activity exceeding 20 %. These compounds were further tested in dose-response experiments to determine their inhibitory potency, and IC50 values were calculated. Among the tested compounds, ethacrynic acid (2-[2,3-dichloro-4-(2- methylidenebutanoyl)phenoxy]aceticacid) and PCIPYR-0303 ((5-Chloro-1-cyclopropylmethyl-6-oxo-1,6-dihydro-pyridazin-4-yl)-pyridin-2-yl-acetonitrile) showed the most consistent and potent inhibitory effects. Steady-state kinetic studies were conducted using these two compounds to investigate their binding mechanisms. Preliminary results indicated that ethacrynic acid showed uncompetitive inhibition kinetics, while PCIPYR-0303 had a mixed type of inhibition.Masteroppgave i FarmasiFARM399/05HMATF-FAR
Sea ice variability from the penultimate glacial to the last interglacial in the Eastern Fram Strait
Get PDFThe ongoing reduction of Arctic sea ice underscores the need to understand the drivers behind sea ice variability and associated ocean-climate impacts. The Last Interglacial, Marine Isotope (sub)Stage (MIS) 5e, and its transitions offer insights into sea ice variability during a period warmer than pre-industrial, and intervals of large climatic changes. This study examines a marine sediment core from the eastern Fram Strait, covering late MIS 6 to early MIS 5b (140–90 ka). We analysed organic biomarkers, including the PIP25 sea ice index and dinoflagellate cyst assemblages, complemented by stable oxygen isotopes, total organic carbon, and sediment physical properties (ice rafted debris, X-ray fluorescence, magnetic susceptibility). Our findings demonstrate a progression from extensive sea ice cover during late MIS 6 to a marginal ice zone during Termination II (T II) and open ocean conditions during MIS 5e, influenced by the Svalbard-Barents Sea Ice Sheet (SBIS) and warm Atlantic surface waters, superimposed on the gradual changes in Northern Hemisphere summer insolation. During late MIS 6, intermittent local polynyas formed by katabatic winds and Atlantic water intrusions temporarily disrupted the sea ice cover. During T II, the marginal ice zone environment, combined with organic matter-rich meltwater influx from the retreating SBIS may have enhanced the biological pump. MIS 5e exhibited a “two-step” warming with the strongest influence of Atlantic waters around ~120 ka. Low to absent concentrations of biomarkers and dinoflagellate cysts immediately following MIS 5e complicate interpretations of sea ice and oceanic conditions during MIS 5d to MIS 5c, a crucial climatic interval characterised by periods with northern hemisphere summer insolation values comparable to today. These findings highlight the complexities of understanding Arctic sea ice responses to ocean-climate drivers and the need for further investigation into the unresolved MIS 5 proxy signals, crucial for improving our understanding of future sea ice decline and the associated ocean-climate impactspublishedVersio
Midtøsten i læreboka - historiedidaktiske perspektiver på lærebøker i endring
Get PDFHistorie mastergradsoppgaveHIS350MAHF-LÆHRMAHF-HI
Sports-Related Advertising in Response to Contemporary Social Discourses
No full textSyftet med denna studie är att analysera hur tre sportrelaterade reklamfilmer använder retoriska strategier för att förmedla ideologiska budskap och påverka samtida samhällsdiskurser. Genom kvalitativ textanalys undersöks reklamfilmerna i ett bredare socialt sammanhang för att förstå hur samhälleliga faktorer kan forma deras narrativ och de frågor de lyfter.
Analysen vilar på ett teoretiskt ramverk som innefattar Aristoteles retoriska övertalningsmedel, Lloyd F. Bitzers begrepp om den retoriska situationen, Jens E. Kjeldsens och Roland Barthes perspektiv på visuell retorik, John B. Thompsons och Michael Freedens teorier om ideologi, samt bidrag från Helge Østbye m.fl. om reklamformer och från David Bordwell och Kristin Thompson om narrativ struktur.
Resultatet visar att dessa tre reklamfilmer svarar på specifika retoriska situationer i sin samtid, men förblir relevanta även idag. De använder retoriska grepp för att engagera sig i kritiska samhällsdiskurser, särskilt sådana som rör marginalisering av vissa grupper, och uppmanar tittaren till reflektion och handling för social förändring.The purpose of this study is to analyze how three sports-related video advertisements use rhetorical strategies to convey ideological messages and influence contemporary social discourse. Through qualitative text analysis, the advertisements are examined within a broader social context to understand how societal factors can shape their narratives and the issues they address.
The analysis is grounded in a theoretical framework that includes Aristotle’s rhetorical appeals, Lloyd F. Bitzer’s concept of the rhetorical situation, Jens E. Kjeldsen’s and Roland Barthes’ perspectives on visual rhetoric, John B. Thompson’s and Micheal Freeden’s theories on ideology, as well as contributions from Helge Østbye et al. on advertising forms and from David Bordwell and Kristin Thompson on narrative structure.
The findings suggest that these three video advertisements respond to specific rhetorical situations of their time while remaining relevant today. They employ rhetorical strategies to engage with critical social discourses, particularly those addressing the marginalization of certain groups, encouraging viewers to reflect and take action toward social change.Masteroppgave i medier og kommunikasjonMEVI350MASV-MEV
Owning the Competition: A Theoretical Analysis of Market Power, Innovation, and Welfare under Overlapping Ownership
Get PDFThe presence of overlapping ownership has increased significantly over the past decade, sparking a rise in both theoretical and empirical literature discussing its effects on firms and consumers in the market.
When focusing on the effect that overlapping ownership has on competition, it is commonly assumed to soften incentives to compete between rival firms, thereby reducing total welfare. However, overlapping ownership may also influence another strategic decision made by firms: their investments in research and development (R\&D). Such investments can reduce production costs, increase profits, and potentially improve overall welfare in the market.
In this thesis, I first present a symmetric duopoly model, before I extend it to an asymmetric setting to illustrate how the relationship between reduced output (due to softened competition) and increased R\&D investment may vary depending on model assumptions.
The findings show that in the symmetric model, increased overlapping ownership reduces total output, raises R\&D investment if technological spillovers in the market are sufficiently large, and decreases welfare unless the spillovers are high enough. In the asymmetric model, however, these effects depend on the degree of asymmetry. By assuming that only one firm holds shares in its competitor, the impacts on output and R\&D investment differ across the firms. This introduces the possibility of positive net welfare effects under certain conditions—even with lower levels of spillover.MasteroppgaveECON391MASV-SØKPROF-SØ