Now showing items 4401-4420 of 5442

    • Single-mode limit and bending losses for shallow Rib Si3N4 waveguides 

      Dullo, Firehun Tsige; Tinguely, Jean-Claude; Solbø, Stian; Hellesø, Olav Gaute (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-01-07)
      The single-mode limit and bending losses for shallow rib waveguides are studied using the full vectorial film mode matching method. The maximum rib height for single-mode waveguides is found to be on the order of 10 nm for a rib width of 2 m and a wavelength of 785 nm, with the exact value depending on the core thickness and the polarization. Bending losses are calculated as a function of several ...
    • Quantum chemical studies of asymmetric reactions: Historical aspects and recent examples 

      Hopmann, Kathrin Helen (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-02-18)
      Asymmetric catalysis is essential for the synthesis of chiral compounds such as pharmaceuticals, agrochemicals, fragrances, and flavors. For rational improvement of asymmetric reactions, detailed mechanistic insights are required. The usefulness of quantum mechanical (QM) studies for understanding the stereocontrol of asymmetric reactions was first demonstrated around 40 years ago, with impressive ...
    • The immediate global responses of Aliivibrio salmonicida to iron limitations 

      Thode, Sunniva Katharina; Kahlke, Tim; Robertsen, Espen Mikal; Hansen, Hilde; Haugen, Peik (Journal article; Tidsskriftartikkel, 2015-02-04)
      <i>Background</i>: Iron is an essential micronutrient for all living organisms, and virulence and sequestration of iron in pathogenic bacteria are believed to be correlated. As a defence mechanism, potential hosts therefore keep the level of free iron inside the body to a minimum. In general, iron metabolism is well studied for some bacteria (mostly human or animal pathogens). However, this area ...
    • The autoinducer synthases LuxI and AinS are responsible for temperature-dependent AHL production in the fish pathogen Aliivibrio salmonicida 

      Hansen, Hilde; Purohit, Amit Anand; Leiros, Hanna-Kirsti S.; Johansen, Jostein; Kellermann, Stefanie J.; Bjelland, Ane Mohn; Willassen, Nils Peder (Journal article; Tidsskriftartikkel, 2015-03-24)
      Background: Quorum sensing (QS) is a cell-to-cell communication system used by bacteria to regulate activities such as virulence, bioluminescence and biofilm formation. The most common QS signals in Gram-negative bacteria are N-acyl-homoserine lactones (AHLs). Aliivibrio salmonicida is the etiological agent of cold water vibriosis in Atlantic salmon, a disease which occurs mainly during seasons ...
    • Consensus Clustering Using kNN Mode Seeking 

      Myhre, Jonas Nordhaug; Mikalsen, Karl Øyvind; Løkse, Sigurd; Jenssen, Robert (Chapter; Bokkapittel, 2015-06-09)
      In this paper we present a novel clustering approach which combines two modern strategies, namely consensus clustering, and two stage clustering as represented by the mean shift spectral clustering algorithm. We introduce the recent kNN mode seeking algorithm in the consensus clustering framework, and the information theoretic kNN Cauchy Schwarz divergence as foundation for spectral clustering. In ...
    • Biocryomorphology: integrating microbial processes with ice surface hydrology, topography and roughness 

      Cook, J.; Edwards, A.; Hubbard, Alun Lloyd (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-12-02)
    • Data-intensive computing infrastructure systems for unmodified biological data analysis pipelines 

      Bongo, Lars Ailo; Pedersen, Edvard; Ernstsen, Martin (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-11-18)
      Biological data analysis is typically implemented using a deep pipeline that combines a wide array of tools and databases. These pipelines must scale to very large datasets, and consequently require parallel and distributed computing. It is therefore important to choose a hardware platform and underlying data management and processing systems well suited for processing large datasets. There are many ...
    • UAV photogrammetry and structure from motion to assess calving dynamics at Store Glacier, a large outlet draining the Greenland ice sheet 

      Ryan, Johnny C.; Hubbard, Alun Lloyd; Box, Jason E.; Todd, Joe; Christoffersen, Poul; Carr, J. Rachel; Holt, Tom O.; Snooke, Neal A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-01-06)
      This study presents the application of a costeffective, unmanned aerial vehicle (UAV) to investigate calving dynamics at a major marine-terminating outlet glacier draining the western sector of the Greenland ice sheet. The UAV was flown over Store Glacier on three sorties during summer 2013 and acquired over 2000 overlapping, geotagged images of the calving front at an ∼ 40 cm ground sampling ...
    • Kvik: three-tier data exploration tools for flexible analysis of genomic data in epidemiological studies 

      Fjukstad, Bjørn; Olsen, Karina Standahl; Jareid, Mie; Lund, Eiliv; Bongo, Lars Ailo (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-03-30)
      Kvik is an open-source system that we developed for explorative analysis of functional genomics data from large epidemiological studies. Creating such studies requires a significant amount of time and resources. It is therefore usual to reuse the data from one study for several research projects. Often each project requires implementing new analysis code, integration with specific knowledge bases, ...
    • Open-ended recursive approach for the calculation of multiphoton absorption matrix elements 

      Friese, Daniel Henrik; Beerepoot, Maarten T. P.; Ringholm, Magnus; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-02-11)
      We present an implementation of single residues for response functions to arbitrary order using a recursive approach. Explicit expressions in terms of density-matrix-based response theory for the single residues of the linear, quadratic, cubic, and quartic response functions are also presented. These residues correspond to one-, two-, three- and four-photon transition matrix elements. The newly ...
    • Open-Ended Recursive Calculation of Single Residues of Response Functions for Perturbation-Dependent Basis Sets 

      Friese, Daniel Henrik; Ringholm, Magnus; Gao, Bin; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-09-09)
      We present theory, implementation, and applications of a recursive scheme for the calculation of single residues of response functions that can treat perturbations that affect the basis set. This scheme enables the calculation of nonlinear light absorption properties to arbitrary order for other perturbations than an electric field. We apply this scheme for the first treatment of two-photon circular ...
    • Seabed morphology and sedimentary processes on high-gradient trough mouth fans offshore Troms, northern Norway 

      Rydningen, Tom Arne; Laberg, Jan Sverre; Kolstad, Vidar (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-10-01)
      Trough mouth fans (TMF) situated at the mouths of formerly glaciated cross-shelf troughs are important paleoclimatic archives. Whereas the sedimentary processes of large, low-gradient TMFs have received considerable interest, little attention has been paid to the other end member of this landform class, i.e. TMFs with higher slope gradients. Detailed swath-bathymetric data and seismic profiles from ...
    • Multiphysics Simulation of Infrared Signature of an Ice Cube 

      Khawaja, Hassan Abbas; Rashid, Taimur; Eiksund, Oddmar; Brodal, Eivind; Edvardsen, Kåre (Conference object; Konferansebidrag, 2015-12-11)
      This poster presents the Multiphysics numerical methodologies used to simulate the Infrared (IR) signature of an ice cube when taken out of the cold environment (-28 C) and allowed to warm at room temperature conditions by means of natural convection. The ice cube is chosen to simplify the geometry. The cubical geometry can be discretized simply and hence allows easy application of Multiphysics ...
    • Absolute NMR shielding scales and nuclear spin–rotation constants in 175LuX and 197AuX (X= 19F, 35Cl, 79Br and 127I) 

      Demissie, Taye Beyene; Jaszuński, Michal; Komorovsky, Stanislav; Repisky, Michal; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-10-28)
      We present nuclear spin–rotation constants, absolute nuclear magnetic resonance (NMR) shielding constants, and shielding spans of all the nuclei in 175LuX and 197AuX (X = 19F, 35Cl, 79Br, 127I), calculated using coupled-cluster singles-and-doubles with a perturbative triples (CCSD(T)) correction theory, four-component relativistic density functional theory (relativistic DFT), and non-relativistic DFT. ...
    • Communication: The absolute shielding scales of oxygen and sulfur revisited 

      Komorovsky, Stanislav; Repisky, Michal; Malkin, Elena; Ruud, Kenneth; Gauss, Jürgen (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-03-04)
      We present an updated semi-experimental absolute shielding scale for the 17O and 33S nuclei. These new shielding scales are based on accurate rotational microwave data for the spin–rotation constants of H2 17O [Puzzarini et al., J. Chem. Phys. 131, 234304 (2009)], C17O [Cazzoli et al., Phys. Chem. Chem. Phys. 4, 3575 (2002)], and H2 33S [Helgaker et al., J. Chem. Phys. 139, 244308 (2013)] ...
    • Relativistic four-component calculations of indirect nuclear spin-spin couplings with efficient evaluation of the exchange-correlation response kernel 

      Kristkova, Anezka; Komorovsky, Stanislav; Repisky, Michal; Malkin, Vladimir G.; Malkina, Olga L. (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-03-16)
      In this work, we report on the development and implementation of a new scheme for efficient calculation of indirect nuclear spin-spin couplings in the framework of four-component matrix Dirac-Kohn-Sham approach termed matrix Dirac-Kohn-Sham restricted magnetic balance resolution of identity for J and K, which takes advantage of the previous restricted magnetic balance formalism and the density ...
    • Chemometric analysis for pollution source assessment of harbour sediments in Arctic locations 

      Pedersen, Kristine Bondo; Lejon, Tore; Jensen, Pernille E.; Ottosen, Lisbeth M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-04-16)
      Pollution levels, pollutant distribution and potential source assessments based on multivariate analysis (chemometrics) were made for harbour sediments from two Arctic locations; Hammerfest in Norway and Sisimiut in Greenland. High levels of heavy metals were detected in addition to organic pollutants. Preliminary assessments based on Principal Component Analysis (PCA) revealed different sources and ...
    • Multivariate methods for evaluating the efficiency of electrodialytic removal of heavy metals from polluted harbour sediments 

      Pedersen, Kristine Bondo; Kirkelund, Gunvor M.; Ottosen, Lisbeth M.; Jensen, Pernille E.; Lejon, Tore (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-02-11)
      Chemometrics was used to develop a multivariate model based on 46 previously reported electrodialytic remediation experiments (EDR) of five different harbour sediments. The model predicted final concentrations of Cd, Cu, Pb and Zn as a function of current density, remediation time, stirring rate, dry/wet sediment, cell set-up as well as sediment properties. Evaluation of the model showed that ...
    • Microbial methane formation in deep aquifers of a coal-bearing sedimentary basin, Germany 

      Gründger, Friederike; Jimenez, N.; Thielemann, T.; Straaten, N.; Lüders, T.; Richnow, H. H.; Krüger, M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-03-20)
      Coal-bearing sediments are major reservoirs of organic matter potentially available for methanogenic subsurface microbial communities. In this study the specific microbial community inside lignite-bearing sedimentary basin in Germany and its contribution to methanogenic hydrocarbon degradation processes was investigated. The stable isotope signature of methane measured in groundwater and coal-rich ...
    • Description of spatio-temporal gait parameters in elderly people and their association with history of falls: Results of the population-based cross-sectional KORA-Age study 

      Thaler-Kall, Kathrin; Peters, Annette; Thorand, Barbara; Grill, Eva; Autenrieth, Christine S.; Horsch, Alexander; Meisinger, Christa (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-03-25)
      Background: In this epidemiological study we described the characteristics of spatio-temporal gait parameters among a representative, population-based sample of 890 community-dwelling people aged 65 to 90 years. In addition, we investigated the associations between certain gait parameters and a history of falls in study participants. <p>Methods: In descriptive analyses spatio-temporal gait parameters ...