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Now showing items 4537-4556 of 4765
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Understanding Pooling in Graph Neural Networks
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-07-21)Many recent works in the field of graph machine learning have introduced pooling operators to reduce the size of graphs. In this article, we present an operational framework to unify this vast and diverse literature by describing pooling operators as the combination of three functions: selection, reduction, and connection (SRC). We then introduce a taxonomy of pooling operators, based on some of ... -
Understanding the Cool DA White Dwarf Pulsator, G29–38
(Journal article; Tidsskriftartikkel; Peer reviewed, 1997-10-10)The white dwarfs are promising laboratories for the study of cosmochronology and stellar evolution. Through observations of the pulsating white dwarfs, we can measure their internal structures and compositions, critical to understanding post main sequence evolution, along with their cooling rates, allowing us to calibrate their ages directly. The most important set of white dwarf variables to ... -
Understanding the Influence of Lewis Acids on CO2 Hydrogenation: The Critical Effect Is on Formate Rotation
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-11)Lewis acids (LAs) have been shown to accelerate hydrogenation of C0<sub>2</sub>, but the underlying mechanistic details remain to be elucidated. We have employed computational methods to investigate how LAs affect CO<sub>2</sub> hydrogenation with a range of known metal-hydrides (L<sub>n</sub>Ir–H, L<sub>n</sub>Ru–H, L<sub>n</sub>Mn–H, L<sub>n</sub>Co–H). Our results show that LAs can alter the ... -
Undersøkelse av ustabilt fjellparti ved Adjet, Storfjord, Troms. Betydningen av ulike kategorier av glideplan i berggrunnen og mekanismer for utglidning
(Master thesis; Mastergradsoppgave, 2015-05-15)Strukturelle element i berggrunnen kan ha stor betydning for utvikling av ustabile fjellparti og fjellskred. I dette studiet vil det fokuseres på hvilken rolle strukturelle element i berggrunnen har hatt å si for skredhendelsene og deformasjonen i området og hvordan disse har preget det geologiske bildet. Det ustabile fjellpartiet er lokalisert på fjellet Adjet ved tettstedet Skibotn i Storfjord ... -
Undervisning av globale klimaendringar
(Master thesis; Mastergradsoppgave, 2012-11-05)Denne masteroppgåva beskriv korleis naturfaglærarar underviser i temaet globale klimaendringar på Vg1-nivå i vidaregåande opplæring, og kva utfordringar dei møter i denne undervisninga. Studien bruker metodetriangulering og kombinerer dei kvalitative metodane fokusgruppeintervju og observasjon med ei kvantitativ spørjeskjemaundersøking. Fokusgruppeintervjua danna grunnlaget for utarbeidinga av ... -
Undervisning av NMR : en formativ problembasert tilnærming
(Master thesis; Mastergradsoppgave, 2012-05-15)Denne oppgaven presenterer resultatene fra et studie hvor en ny undervisningsmetode er prøvd ut i undervisningen av kjernemagnetisk resonans (NMR). Undervisningen er elevsentrert med bruk av formative undervisningsverktøy, hvor det er benyttet elementer fra den deduktive og den teknologiske undervisningsmetoden. Data er samlet inn i forbindelse med gjennomføringen av et undervisningsopplegg hvor ... -
Undervisning i bioteknologi : laboratoriearbeid
(Master thesis; Mastergradsoppgave, 2010-06-01)Gjennom de siste ti årene har en rask utvikling av nye bioteknologiske metoder vært fremtredene som et resultat av teknologiens fremvekst. For den moderne lærer, i den videregående skole, medfører dette stadig nye utfordringer innenfor tilrettelegging av faglig oppdatert undervisning. Spesielt krevende er det å kunne tilby laboratorieundervisning som gir god læring, og hvor utstyr og materiell ikke ... -
Undervisning i bioteknologi : muligheter og utfordringer
(Master thesis; Mastergradsoppgave, 2008-12-15)Innenfor feltene biokjemi, genetikk og mikrobiologi har det de siste tjue årene vært en rask utvikling av nye metoder i takt med den teknologiske utviklingen, og disse metodene utgjør det vi kaller for bioteknologi. Bioteknologi inngår som målområder i læreplanen både for grunnutdanningen og videregående opplæring. Som følge av den raske utviklingen av feltet har derfor skolene en spesiell ... -
Undervisning i økologi. Forskningsbasert undervisning i tundraregionen
(Master thesis; Mastergradsoppgave, 2012-06-01)TUNDRA Schoolnet er et forskningsbasert skoleprosjekt som ønsker å gi et kunnskapsløft i hvordan klimaendringer påvirker den lokale naturen blant lærere og elever i tundraregionen. Hovedfokuset i denne masteroppgaven ble utviklingen av økologiundervisningsopplegget ”Se rovdyrene!” som skulle tas i bruk på 4 deltakerskoler på Varangerhalvøya. Utdanningssamfunnet er opptatt av at elevers engasjement ... -
Unequivocal structure confirmation of a breitfussin analog by anisotropic NMR measurements
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-09-21)Structural features of proton-deficient heteroaromatic natural products, such as the breitfussins, can severely complicate their characterization by NMR spectroscopy. For the breitfussins in particular, the constitution of the five-membered oxazole central ring cannot be unequivocally established via conventional NMR methods when the 4′-position is halogenated. The level of difficulty is exacerbated ... -
Unexpected Molecular Structure of a Putative Rhenium-Dioxo-Benzocarbaporphyrin Complex. Implications for the Highest Transition Metal Valence in a Porphyrin-Type Ligand Environment
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-10-18)A combination of quantum chemical calculations and synthetic studies was used to address the possibility of very high (>6) valence states of transition metals in porphyrin‐type complexes. With corrole as a supporting ligand, DFT calculations ruled out Re(VII) and Ir(VII) dioxo complexes as stable species. Attempted rhenium insertion into benzocarbaporphyrin (BCP) ligands on the other hand led to two ... -
Ungdom og høyreekstrem radikalisering på internett - en litteraturstudie. Hvordan kan vi forebygge at unge radikaliseres til høyreekstremisme på nett?
(Master thesis; Mastergradsoppgave, 2022-06-01)Høyreekstreme grupper benytter i stor grad internett og sosiale medier til å rekruttere og radikalisere nye medlemmer. Samtidig har internett blitt en viktig del av de fleste menneskers liv, og særlig barn og unge tilbringer mye tid på ulike nettsteder og sosiale medier. Dette, sammen med det faktum at både Norge og andre europeiske og vestlige land opplever en økning i antall unge som radikaliseres ... -
Uni- and triaxial accelerometric signals agree during daily routine, but show differences between sports
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-10-10)Accelerometers objectively monitor physical activity, and ongoing research suggests they can also detect patterns of body movement. However, different types of signal (uniaxial, captured by older studies, vs. the newer triaxial) and or/device (validated Actigraph used by older studies, vs. others) may lead to incomparability of results from different time periods. Standardization is desirable. We ... -
The Unidirectional Pulse Propagation Equation for Cylindrical Vector modes
(Master thesis; Mastergradsoppgave, 2015-07-27)A new model for the unidirectional pulse propagation equations (UPPE) was developed by Per Jacobsen[1], this model is based on the assumption of cylindrical vector (CV) modes. The model will be strong for CV type electrical eld representations where only a few modes will be excited. In this thesis we will investigate the model further. The model will be implemented as a pseudo spectral method where ... -
Unification of sparse Bayesian learning algorithms for electromagnetic brain imaging with the majorization minimization framework
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-10-01)Methods for electro- or magnetoencephalography (EEG/MEG) based brain source imaging (BSI) using sparse Bayesian learning (SBL) have been demonstrated to achieve excellent performance in situations with low numbers of distinct active sources, such as event-related designs. This paper extends the theory and practice of SBL in three important ways. First, we reformulate three existing SBL algorithms ... -
Unified detection system for automatic, real-time, accurate animal detection in camera trap images from the arctic tundra
(Master thesis; Mastergradsoppgave, 2017-06-01)A more efficient and effective approach for detecting animal species in digital images is required. Every winter, the Climate-ecological Observatory for Arctic Tundra (COAT) project deploys several dozen camera traps in eastern Finnmark, Norway. These cameras capture large volumes of images that are used to study and document the impact of climate changes on animal populations. Currently, the images ... -
Unified Power Control of Permanent Magnet Synchronous Generator Based Wind Power System with Ancillary Support during Grid Faults
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-10-08)A unified active power control scheme is devised for the grid-integrated permanent magnet synchronous generator-based wind power system (WPS) to follow the Indian electricity grid code requirements. The objective of this paper is to propose control schemes to ensure the continuous integration of WPS into the grid even during a higher percentage of voltage dip. In this context, primarily a constructive ... -
Unified transport scaling laws for plasma blobs and depletions
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-06-14)We study the dynamics of seeded plasma blobs and depletions in an (effective) gravitational field. For incompressible flows, the radial center of mass velocity of blobs and depletions is proportional to the square root of their initial cross-field size and amplitude. If the flows are compressible, this scaling holds only for ratios of amplitude to size larger than a critical value. Otherwise, the ... -
A unique class I polyhydroxyalkanoate synthase (PhaC) from Brevundimonas sp. KH11J01 exists as a functional trimer: A comparative study with PhaC from Cupriavidus necator H16
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-05-06)Polyhydroxyalkanoates (PHAs) are natural biodegradable polyesters that are produced by numerous prokaryotic microorganisms primarily as a carbon- and energy reserve. The PhaC enzyme catalyzes the last step in the PHA biosynthesis pathway and synthesizes PHA polymers from hydroxyalkanoic acids. A type I PhaC from a PHAproducing marine bacterium Brevundimonas sp. KH11J01 (BrPhaC) was identified, ... -
Unique core genomes of the bacterial family vibrionaceae: insights into niche adaptation and speciation
(Journal article; Tidsskriftartikkel; Peer reviewed, 2012)The criteria for defining bacterial species and even the concept of bacterial species itself are under debate, and the discussion is apparently intensifying as more genome sequence data is becoming available. However, it is still unclear how the new advances in genomics should be used most efficiently to address this question. In this study we identify genes that are common to any group of genomes ...
