Hydrography and circulation in the Filchner Depression, Weddell Sea, Antarctica

Cold and dense Ice Shelf Water (ISW) emerging from the Filchner-Ronne Ice Shelf cavity in the southwestern Weddell Sea flows northward through the Filchner Depression to eventually descend the continental slope and contribute to the formation of bottom water. New ship-born observations of hydrography and currents from Filchner Depression in January 2013 suggest that the northward flow of ISW takes place in a mid-depth jet along the eastern flank of the depression, thus questioning the traditional view with outflow along the western flank. This interpretation of the data is supported by results from a regional numerical model, which shows that ISW flowing northward along the eastern coast of Berkner Island turns eastward and crosses the depression to its eastern side upon reaching the Filchner ice front. The ice front represents a sudden change in the thickness of the water column and thus a potential vorticity barrier. Transport estimates of northward ISW flux based on observations ranges from 0.2-1.0 Sv

Machine learning for property valuation : an empirical study of how property price predictions can improve property tax estimations in Norway

This thesis investigates whether machine learning methods can improve property price predictions, leading to more accurate property tax estimations in Norway. This study is important to ensure fair and trustworthy taxation for Norwegian taxpayers. The current method for predicting property values is a hedonic pricing model, developed by Statistics Norway using multiple linear regression. This model shows that 25% of all predicted property prices deviate by more than 20% of their observed price. These predictions are further used to estimate property tax, and the deviation in the current model suggests there is potential for improvement. The use of machine learning to improve property price predictions has yet to be explored by Statistics Norway. Consequently, this thesis investigates the predictive performance of more advanced machine learning methods on transacted properties, covering three districts in Oslo, from 2005 to 2020. These methodologies include decision trees, Random Forest, gradient boosting, and neural networks. All methodologies, except decision trees, performed better than multiple linear regression. Gradient boosting produced the best results, with an RMSE of 0.1140 compared to an RMSE of 0.2132 from the multiple linear regression. The total percentage of predictions deviating more than 20% of observed values were 6.4% using the gradient boosting approach, providing an improvement of 74% to the current method. The main conclusion drawn from this research confirms the superiority of machine learning methods for property valuation, capable of improving the current methods for estimating property tax in Norway. Additionally, the use of Local Interpretable Model-agnostic Explanations (LIME) can make the results transparent and compliant with current GDPR legislation for automated decisions. This thesis recommends the implementation of gradient boosting as the new method for property valuation in Norway. Keywords – Property tax, machine learning, LIME, GDPR, gradient boostingnhhma

Acute toxicity testing of the tire rubber-derived chemical 6PPD-quinone on Atlantic salmon (Salmo salar) and brown trout (Salmo trutta)

Recent identification of 6PPD-quinone as the chemical causing acute toxicity in coho salmon has led to substantial concern regarding toxicity of this contaminant for other aquatic species. Environmental occurrence of 6PPD-quinone is probably high as it is an oxidation product of a common tire rubber additive. Research on 6PPD-quinone toxicity in fish has revealed a rather unusual pattern, with closely related species exhibiting responses ranging from extreme sensitivity to no effect. Of eleven previously studied fish species, 6PPD-quinone was toxic to four. The species-specific toxicity of 6PPD-quinone complicates urgently needed environmental risk assessment. We investigated acute toxicity of 6PPD-quinone in Atlantic salmon and brown trout alevins (sac fry). These species have previously not been tested for sensitivity to 6PPD-quinone. The fish were exposed in static conditions in eight treatments with initial concentrations ranging from 0.095–12.16 µg/L. Fish were observed for 48 h and changes in concentrations of 6PPD-quinone were monitored throughout the experiment. No mortalities or substantial changes in behaviour were recorded in either Atlantic salmon or brown trout. This provides an important first step in assessing effects of 6PPD-quinone on these highly economically and culturally important species.acceptedVersio

Presence of 6PPD-quinone in runoff water samples from Norway using a new LC–MS/MS method

The chemical 6PPD-quinone is highly toxic to some fish species of the Oncorhynchus and Salvelinus genera and is the oxidation product of the common car tire additive 6PPD. We present a new sample preparation method that involves liquid-liquid extraction of water samples followed by silica-based solid phase extraction prior to LC–MS/MS analysis. The new sample preparation method showed good analyte recovery from spiked water samples (78%–91%) and a low ion suppression effect, surpassing previously published methods. This new method was successfully validated, achieving a limit of quantification of 5 ng/L and estimated expanded measurement uncertainty of 18.6%. In a proof-of-concept study, the method was applied to several water samples from various sources in Southern Norway. These were runoff samples from tunnel washing, from a tunnel runoff treatment plant and downstream of the plant drain. In addition, two water samples from puddles were included: one was run-off from an artificial soccer turf field and one from a puddle on a country road. The results of the analyses revealed that the concentration of 6PPD-quinone was above the LC50 reported for coho salmon (Oncorhynchus kisutch) in all samples except the samples from and downstream of the treatment plant. The highest measured concentration was 258 ng/L, which is the 2.7-fold of the reported LC50 in coho salmon (95 ng/L). Our initial data emphasize the need for more comprehensive environmental monitoring of 6PPD-quinone as well as toxicological studies in aquatic organisms. car tire, liquid chromatography, mass spectrometry, runoff water, artificial turf pitch, 6PPDQ, 6PPD-quinonepublishedVersio

Føresetnader for å ta vare på dei nordiske språka i språkteknologien

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The teacher’s function in literature conversations. Guidance, support and dialogue.

Bacheloroppgave, grunnskolelærerutdanning, 2014.Norsk: Temaet i denne bacheloroppgaven er lærerens rolle i litterære samtaler. Hensikten med oppgaven er å finne ut om støtte og veiledning fra læreren har innvirkning på elevers deltakelse i litterære samtaler. Problemstillingen min er: Hvordan kan veiledning og støtte fra læreren bidra til elevenes deltakelse i samtaler om litteratur? Oppgaven er basert på kvalitativ datainnsamling, hvor jeg har tatt i bruk deltakende observasjon i samtale med elever. Samtalen dreide som om en bok vi hadde lest og denne samtalen ble utført på fire forskjellige grupper, en gang med sterk lærerstyring og en gang med en svakere lærerstyring. Dette for å finne svar på problemstillingen min i forhold til hvor mye veiledning og støtte spiller inn for deltakelsen til elevene. Funnene i observasjonene knyttes opp mot teori. Teorien det er tatt utgangspunkt i er: sosiokulturell læringsteori med Vygotsky, Bruner, Bakthin og Dyste, samt teori om litterære samtaler hentet fra Anne- Kari Skarðhamar, Åsmund Hennig, Tove Sommervold og Kunnskapsløftet. Resultatet av mine undersøkelser gav flere indikasjoner på at litterære samtaler elevene i mellom, uten noe særlig form for styring fra læreren, ikke vil føre til det store læringsutbytte for dem. Ut i fra hvordan min undersøkelse var organisert, viste det seg at det var signifikante forskjeller i elevenes deltakelse i de to metodene, sterk og svak lærerstyring.English: This bachelor’s theme is the teacher’s function in literature conversations. The purpose is to investigate if support and guidance from the teacher has impact concerning the student’s participation in such conversations. My thesis is: How can guidance and support from the teacher contribute regarding participation in literature conversations? The assignment is based on qualitative collection of data, where I have used sympathetic observation in conversation with students. The conversation dealt with a book we had read, and the students was conducted in four different groups; once with strong teacher directive in literature, the other with weak teacher directive. This was to investigate my thesis concerning how much of a role guidance and support plays in the student’s contribution. The results from my observations are then tied up to theory. The theory used is sociocultural learning theory by Vygosky, Bruner, Bakthin and Dyste, and theory about literature conversations from Anne-Kari Skardhamar, Åsmund Hennig, Tove Sommervold and Kunnskapsløftet. The result from my investigations shows several indications that literature conversations among students, without directives from the teacher, gives a negative learning outcome. My study shows significant differences in the student’s contribution in the two methods; strong and weak teacher directive

Rethinking the role of solar energy under location specific constraints

In this manuscript we evaluate the potential of photovoltaic systems to meet some dedicated energy demand in specific geographic locations. Our approach is based on location-specific constraints rather than on pre-established, location-independent methodologies or assumptions. First, we propose that a thorough analysis of the socio-economic and technical possibilities of a location must act as the guide to optimize the deployment of renewables. This requires detailed knowledge of the area. Second, we propose that optimizing the exploitation of renewables by focusing on a particular location can also lead to successful outcomes with global impact. With this in mind we focus our attention on the Arctic region, known for its highly seasonal solar availability, and the challenge posed by increasing cruise ship tourism and corresponding air pollution. Our study targets Tromsø city, Norway, and we show that solar energy generation could be a strong contribution for charging cruise ships in the summer with no need for generation and transmission investments. Our study opens the door to shifting to a location specific paradigm to seek sustainable energy solutions with the possibility to have a global impact

Detecting the linear and non-linear causal links for disturbances in the power grid

Unscheduled power disturbances cause severe consequences for customers and grid operators. To avoid suchevents, it is important to identify the causes and localize the sources of the disturbances in the power distribution network. In this work, we focus on a specific power grid in the Arctic region of Northern Norway that experiences an increased frequency of failures of unspecified origin