Fakultet for naturvitenskap og teknologi: Recent submissions
Now showing items 4061-4080 of 5414
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Alt er sukret med risiko. Bruk av risikostyringsteori ved utforming av endringsforslag som berører akuttkirurgi i Nasjonal Helse- og Sykehusplan
(Master thesis; Mastergradsoppgave, 2016-12-17)Oppgaven tar for seg utfordringer i helsevesenet tilknyttet risikostyring. Det skal foretas en gjennomgang av plan- og beslutningsprosessene rundt stortingsmeldingen Nasjonal Helse- og Sykehusplan (2016-2019), for å se nærmere på hvordan prosessene har ført til den foreslåtte omorganiseringen. Sentralisering av akuttkirurgi vil være oppgavens case. Oppgavens problemstilling er: I hvilken grad er de ... -
Fører utsettelsesatferd til økt risiko i trafikken? En studie av bilister
(Master thesis; Mastergradsoppgave, 2016-12-09)Selv om Norge er et av de mest trafikksikre landene i Europa i følge Trygg Trafikk, er det registrert et høyt antall trafikkulykker her til lands med forskjellig skadegrad. Disse utgjør ikke bare en betydelig samfunnsøkonomisk kostnad, men det er også mange familier og personer som blir rammet, derfor er det viktig å kunne forklare hvorfor ulykker oppstår for å kunne begrense kostnadene og skåne ... -
Sources and turnover of organic carbon and methane in fjord and shelf sediments off Northern Norway
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-10-22)To better understand the present and past carbon cycling and transformation processes in methane-influenced fjord and shelf areas of northern Norway, we compared two sediment cores from the Hola trough and from Ullsfjorden. We investigated (1) the organic matter composition and sedimentological characteristics to study the sources of organic carbon (C<sub>org</sub>) and the factors influencing ... -
Statistics of Regional Surface Temperatures after 1900: Long-Range versus Short-Range Dependence and Significance of Warming Trends
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016)This paper studies regional climate variability for the time period 1900–2013 using parsimonious stochastic models. Instrumental data records on 5° × 5°, 2° × 2°, and equal-area grids are examined. A long-range dependent (LRD) stochastic process is used as a simplified description of the multitude of response times in the climate system. Fitting a linear trend to the global mean surface temperature ... -
The origin dependence of the material constants: the permittivity and the inverse permeability
(Journal article; Tidsskriftartikkel; Peer reviewed, 2015-05-26)New derivations of origin-independent expressions for the electric permittivity are presented, starting either from the response function of the current density that defines the absorption coefficient, or from the off-resonance single-photon scattering amplitude that leads to the Kramers–Heisenberg dispersion formula. The resulting expression for the permittivity is compared with earlier work ... -
Auto-correlation function and frequency spectrum due to a super-position of uncorrelated exponential pulses
(Peer reviewed; Journal article; Tidsskriftsartikkel, 2017-03)The auto-correlation function and the frequency power spectral density due to a super-position of uncorrelated exponential pulses are considered. These are shown to be independent of the degree of pulse overlap and thereby the intermittency of the stochastic process. For constant pulse duration and a one-sided exponential pulse shape, the power spectral density has a Lorentzian shape which is flat ... -
Open-ended formulation of self-consistent field response theory with the polarizable continuum model for solvation
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-11-15)The study of high-order absorption properties of molecules is a field of growing importance. Quantumchemical studies can help design chromophores with desirable characteristics. Given that most experiments are performed in solution, it is important to devise a cost-effective strategy to include solvation effects in quantum-chemical studies of these properties. We here present an open-ended ... -
Power law spectra and intermittent fluctuations due to uncorrelated Lorentzian pulses
(Peer reviewed; Journal article; Tidsskriftsartikkel, 2017-02)A stochastic model for intermittent fluctuations due to a super-position of uncorrelated Lorentzian pulses is presented. For a constant pulse duration, this is shown to result in an exponential power spectral density for the stationary process. A random distribution of pulse durations modifies the frequency spectrum, and several examples are shown to result in power law spectra. The distribution of ... -
Using satellite execution to reduce latency for mobile/cloud applications
(Peer reviewed; Journal article; Tidsskriftsartikkel, 2016-02-03)We demonstrate a practical way to reduce latency for mobile .NET applications that interact with cloud services, without disrupting application architectures. We provide a programming abstraction for location-independent code, which has the potential to execute either locally or at a satellite execution environment in the cloud, where other cloud services can be accessed with low latency. This ... -
Modification of the high-latitude ionospheric F region by high-power HF radio waves at frequencies near the fifth and sixth electron gyroharmonics
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-02-01)We study the modification effects of the high-latitude ionospheric F region induced by a highpower O-mode HF radio wave injected towards the magnetic zenith, at frequencies near the fifth and sixth electron gyroharmonics using the EISCAT/Heating facility. Multi-instrument diagnostics with the EISCAT incoherent scatter radar (930 MHz) at Tromsø, Norway, the CUTLASS coherent radar at Hankasalmi, ... -
The behavior of electron density and temperature during ionospheric heating near the fifth electron gyrofrequency
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-01-27)The experimental phenomena involving the changes in electron temperature and electron density as a function of pump frequency during an ionospheric heating campaign at European Incoherent Scatter near Tromsø, Norway, are reported. When the pump frequency is slightly above the fifth electron gyrofrequency, the UHF radar observation shows some apparent enhancements over a wide altitude range in radar ... -
Paleo-methane emissions recorded in foraminifera near the landward limit of the gas hydrate stability zone offshore western Svalbard
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-02-26)We present stable isotope and geochemical data from four sediment cores from west of Prins Karls Forland (ca. 340 m water depth), offshore western Svalbard, recovered from close to sites of active methane seepage, as well as from shallower water depths where methane seepage is not presently observed. Our analyses provide insight into the record of methane seepage in an area where ongoing ocean ... -
Visible-light photocatalytic double C–H Functionalization of indoles: a synergistic experimental and computational study
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-02-21)Herein is disclosed a novel visible-light photocatalytic double C–H functionalization of indoles. The reaction affords 2,3-difunctional- ized indoles in up to 84% yield, but the reaction rate depends strongly on electronic substituent effects. Mechanistic DFT studies and control experiments suggest that the secondary functionalization occurs through an independent photocatalytic oxidation ... -
A complex contour based perfectly matched layer applied to a pattern generating model equation.
(Master thesis; Mastergradsoppgave, 2017-02-17)The observable universe consists of several non equilibrium systems that generate spatiotemporal behaviour in the form of various patterns. As the elementary laws of physics and chemistry are unable to explain the pattern forming behaviour of such systems, scientists have turned to desktop experiments and model equations to gain further insight. The model equations that generate numerical solutions ... -
Separable representations of the Poisson, Helmholtz and complex Helmholtz kernels
(Master thesis; Mastergradsoppgave, 2017-02-15)For high accuracy applications of integral operators in higher dimensions the complexity of operation and storage usually grows exponentially with dimensions. One method that has proven successful for handling these difficulties are the separation of the integral kernels as linear combinations of products of one-dimensional kernels, commonly referred to as separation of variables. In this ... -
A solvable blob-model for magnetized plasmas
(Peer reviewed; Journal article; Tidsskriftsartikkel, 2016-09-06)A simple analytically solvable model for blobs in magnetized plasmas is proposed. The model gives results for a scaling of the blob velocity with the amplitude of the density perturbation. Limiting cases are considered: one where the plasma motion is strictly perpendicular to an externally imposed toroidal magnetic field, and one where the electrons can move along magnetic field lines to compensate ... -
Fluctuation statistics in the scrape-off layer of Alcator C-Mod
(Peer reviewed; Journal article; Tidsskriftsartikkel, 2016-03-30)We study long time series of the ion saturation current and floating potential, sampled by Langmuir probes dwelled in the outboard mid-plane scrape-off layer and embedded in the lower divertor baffle of Alcator C-Mod. A series of ohmically heated L-mode plasma discharges is investigated with line-averaged plasma density ranging from ${{\bar{n}}_{\text{e}}}/{{n}_{\text{G}}}=0.15$ to 0.42, where n G ... -
Oxidative stress in two tropical species after exposure to diesel oil
(Peer reviewed; Journal article; Tidsskriftsartikkel, 2016-08-03)Recent offshore petroleum exploration has increased the risks of oil spills worldwide. We investigated biomarker responses to diesel oil exposure in two tropical and subtropical species, the clam Anomalocardia flexuosa and the polychaete Laeonereis culveri. Animals were exposed to oil-spiked sediment at two different concentrations (0.5 L and 1.0 L m−2). Activities of antioxidant enzymes catalase ... -
Baseline levels of oxidative stress biomarkers in species from a subtropical estuarine system (Paranaguá Bay, southern Brazil)
(Peer reviewed; Journal article; Tidsskriftsartikkel, 2016-08-10)Offshore petroleum exploration has increased the risks of oil spills in coastal tropical and subtropical habitats. Monitoring tools are needed to assess and protect environmental health. We determined baseline values of antioxidant biomarkers (CAT, SOD, GPx, GST, MDA) for five ecologically relevant species in a subtropical system in southern Brazil. Regional baseline levels are compared with literature ... -
Isolation and complete genome sequence of the thermophilic Geobacillus sp. 12AMOR1 from an Arctic deep-sea hydrothermal vent site
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-02-24)Members of the genus Geobacillus have been isolated from a wide variety of habitats worldwide and are the subject for targeted enzyme utilization in various industrial applications. Here we report the isolation and complete genome sequence of the thermophilic starch-degrading Geobacillus sp. 12AMOR1. The strain 12AMOR1 was isolated from deep-sea hot sediment at the Jan Mayen hydrothermal Vent ...