Fakultet for naturvitenskap og teknologi: Recent submissions
Now showing items 4041-4060 of 5327
-
The last 2 Myr of accretionary wedge construction in the central Hikurangi margin (North Island, New Zealand): Insights from structural modeling
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-07-17)Three depth-converted and geologically interpreted seismic profiles provide a clear image of the offshore outer accretionary wedge associated with oblique subduction of the Pacific Plate beneath the central Hikurangi margin. Plio-Quaternary turbidites deposited over the pelagic cover sequence of the Hikurangi Plateau have been accreted to the margin by imbrication along E-verging thrust faults that ... -
Splay fault branching from the Hikurangi subduction shear zone: Implications for slow slip and fluid flow
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-12-25)Prestack depth migration data across the Hikurangi margin, East Coast of the North Island, New Zealand, are used to derive subducting slab geometry, upper crustal structure, and seismic velocities resolved to ∼14 km depth. We investigate the potential relationship between the crustal architecture, fluid migration, and short-term geodetically determined slow slip events. The subduction interface is ... -
A Decade of Biochemical and Structural Studies of the DNA Repair Machinery of Deinococcus radiodurans: Major Findings, Functional and Mechanistic Insight and Challenges
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-04-27)The Deinococcus radiodurans bacterium is extremely resistant to ionising radiation and desiccation and can withstand a 200-fold higher radiation dose than most other bacteria with no loss of viability. The mechanisms behind this extreme resistance are not fully understood, but it is clear that several factors contribute to this phenotype. Efficient scavenging of reactive oxygen species and repair ... -
Reconstruction of hydrographic changes in the southern Norwegian Sea during the past 135 kyr and the impact of different foraminiferal Mg/Ca cleaning protocols
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-08-20)The shallow subsurface hydrography in the southern Norwegian Sea during the past 135,000 years was investigated using parallel measurements of Mg/Ca and δ18O in shells of the planktic foraminiferal species Neogloboquadrina pachyderma. Two cleaning methods were applied prior to Mg/Ca analysis, “Mg cleaning” and “full cleaning” methods. Different results were obtained, which are most likely due to a ... -
Simulating seismic chimney structures as potential vertical migration pathways for CO2 in the Snøhvit area, SW Barents Sea: model challenges and outcomes
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-03-16)Carbon capture and storage (CCS) activities at the Snøhvit field, Barents Sea, will involve carrying out an analysis to determine which parameters affect the migration process of CO2 from the gas reservoir, to what degree they do so and how sensitive these parameters are to any changes. This analysis will aim to evaluate the effects of applying a broad but realistic range of reservoir, fault and gas ... -
The build-up, configuration, and dynamical sensitivity of the Eurasian ice-sheet complex to Late Weichselian climatic and oceanic forcing
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-12-01)The Eurasian ice-sheet complex (EISC) was the third largest ice mass during the Last Glacial Maximum (LGM), after the Antarctic and North American ice sheets. Despite its global significance, a comprehensive account of its evolution from independent nucleation centres to its maximum extent is conspicuously lacking. Here, a first-order, thermomechanical model, robustly constrained by empirical evidence, ... -
Evolution of a high-latitude sediment drift inside a glacially-carved trough based on high-resolution seismic stratigraphy (Kveithola, NW Barents Sea)
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-09-01)Kveithola is a glacially-carved, E-W trending trough located in the NW Barents Sea, an epicontinental shelf sea of the Arctic Ocean located off northern Norway and Russia. A set of confined sediment drifts (the “Kveithola Drift”) is located in the inner part of the trough. In general, drift deposits are commonly characterized by high lateral continuity, restricted occurrence of hiatuses and relatively ... -
Distribution and characteristics of overdeepenings beneath the Greenland and Antarctic ice sheets: Implications for overdeepening origin and evolution
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-09-15)Glacier bed overdeepenings are ubiquitous in glacier systems and likely exert significant influence on ice dynamics, subglacial hydrology, and ice stability. Understanding of overdeepening formation and evolution has been hampered by an absence of quantitative empirical studies of their distribution and morphology, with process insights having been drawn largely from theoretical or numerical studies. ... -
Linking the basement geology along the Africa-South America coasts in the South Atlantic
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-05-13)The match of geological units of the dissected Kaoko-Dom Feliciano-Gariep orogenic system exposed along the coasts of the South Atlantic is poorly understood. Two suites of intrusive rocks crop out in the Angra Fria Bay area, a part of the Coastal Terrane of the Kaoko Belt in Namibia. U–Pb zircon dating of three samples from the younger suite provided ages of 574 ± 6, 586 ± 3 and 584 ± 7 Ma, similar ... -
Level crossings, excess times, and transient plasma-wall interactions in fusion plasmas
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-04-19)Based on a stochastic model for intermittent fluctuations in the boundary region of magnetically confined plasmas, an expression for the level crossing rate is derived from the joint distribution of the process and its derivative. From this the average time spent by the process above a certain threshold level is obtained. This provides novel predictions of plasma–wall interactions due to transient ... -
Magnetic properties with multiwavelets and DFT: The complete basis set limit achieved
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-04-11)Multiwavelets are emerging as an attractive alternative to traditional basis sets such as Gaussian-type orbitals and plane waves. One of their distinctive properties is the ability to reach the basis set limit (often a chimera for traditional approaches) reliably and consistently by fixing the desired precision ε. We present our multiwavelet implementation of the linear response formalism, applied ... -
Analytic calculations of anharmonic infrared and Raman vibrational spectra
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-01-07)Using a recently developed recursive scheme for the calculation of high-order geometric derivatives of frequency-dependent molecular properties [Ringholm et al., J. Comp. Chem., 2014, 35, 622], we present the first analytic calculations of anharmonic infrared (IR) and Raman spectra including anharmonicity both in the vibrational frequencies and in the IR and Raman intensities. In the case of anharmonic ... -
Spatiotemporal patterns of particulate matter (PM) and associations between PM and mortality in Shenzhen, China
(Peer reviewed; Journal article; Tidsskriftsartikkel, 2016-03-02)Background: Most studies on air pollution exposure and its associations with human health in China have focused on the heavily polluted industrial areas and/or mega-cities, and studies on cities with comparatively low air pollutant concentrations are still rare. Only a few studies have attempted to analyse particulate matter (PM) for the vibrant economic centre Shenzhen in the Pearl River Delta. ... -
How accurate is DFT for iridium-mediated chemistry?
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-09-27)Iridium chemistry is versatile and widespread, with superior performance for reaction types such as enantioselective hydrogenation and C−H activation. In order to gain insight into the mechanistic details of such systems, density functional theory (DFT) studies are often employed. But how accurate is DFT for modeling iridium-mediated transformations in solution? We have evaluated how well DFT ... -
Position, swimming direction and group size of fin whales (Balaenoptera physalus) in the presence of a fast-ferry in the Bay of Biscay
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-03-12)We analyze group size, swimming direction and the orientation of fin whales relative to a fast ferry in the Bay of Biscay. Fin whale groups (≥3 individuals) were on average closer to the vessel than single individuals and pairs (F1,114 = 4.94, p = 0.028) and were more often observed within a high-risk angle ahead of the ferry (binomial probability: p = 7.60 × 10−11). Also, small groups tend to swim ... -
Non-nearest neighbour ICD in clusters
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-04-19)Interatomic Coulombic decay (ICD) is an electronic decay process of excited, ionized systems. It has been shown to occur in a multitude of small and large systems. The effects of more than one possible decay partner are discussed in detail illustrated by simulated ICD electron spectra of NeAr clusters and pure Ne clusters. Hereby, the mostly underestimated contribution of decay with non-nearest ... -
Dynamics of the Terra Nova Bay Polynya: The potential of multi-sensor satellite observations
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-10-10)Research on processes leading to formation, maintenance, and disappearance of polynyas in the Polar Regions benefits significantly from the use of different types of remote sensing data. The Sentinels of the European Space Agency (ESA), together with other satellite missions, provide a variety of data from different parts of the electromagnetic spectrum, at different spatial scales, and with ... -
Gas hydrate stability zone of the Barents Sea and Kara Sea region
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-11-29)In this study we assess the present-day gas hydrate stability zone for the Barents Sea and Kara Sea region. Thereby, we make use of a data-based 3D lithosphere-scale pressure and thermal model. The resulting gas hydrate stability zone varies within >1km across the study area and strongly correlates with the local geological settings and the corresponding geothermal gradient. Gas hydrates containing ... -
On the improvement and acceleration of eigenvalue decomposition in spectral methods using GPUs
(Master thesis; Mastergradsoppgave, 2016-12-08)The key objectives in this thesis are; the study of GPU-accelerated eigenvalue decomposition in an effort to uncover both benefits and pitfalls, and then to investigate and facilitate a future GPU implementation of the symmetric QR algorithm with permutations. With the current trend of having ever larger datasets both in terms of features and observations, we propose that GPU computation can help ... -
Neutral atmosphere temperature trends and variability at 90 km, 70°N, 19°E, 2003-2014
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-06-27)Neutral temperatures at 90 km height above Tromsø, Norway, have been determined using ambipolar diffusion coefficients calculated from meteor echo fading times using the Nippon/Norway Tromsø Meteor Radar (NTMR). Daily temperature averages have been calculated from November 2003 to October 2014 and calibrated against temperature measurements from the Microwave Limb Sounder (MLS) on board Aura. ...