• Statistics of weakly nonlinear waves on currents with strong vertical shear 

      Zheng, Zibo; Li, Yan; Ellingsen, Simen Andreas Ådnøy (Journal article; Peer reviewed, 2023)
      We investigate how the presence of a vertically sheared current affects wave statistics, including the probability of rogue waves, and apply it to a real-world case using measured spectral and shear current data from the ...
    • Quantification and uncertainty of root growth stimulation by elevated CO2 in a mature temperate deciduous forest 

      Ziegler, Clare; Kulawska, Aleksandra; Kourmouli, Angeliki; Hamilton, Liz; Shi, Zongbo; MacKenzie, A. Robert; Dyson, Rosemary J.; Johnston, Iain George (Journal article; Peer reviewed, 2023)
      Increasing CO2 levels are a major global challenge, and the potential mitigation of anthropogenic CO2 emissions by natural carbon sinks remains poorly understood. The uptake of elevated CO2 (eCO2) by the terrestrial ...
    • HyperHMM: efficient inference of evolutionary and progressive dynamics on hypercubic transition graphs 

      Moen, Marcus Theodor; Johnston, Iain George (Journal article; Peer reviewed, 2023)
      Motivation: The evolution of bacterial drug resistance and other features in biology, the progression of cancer and other diseases and a wide range of broader questions can often be viewed as the sequential stochastic ...
    • Sequential multilevel assimilation of inverted seismic data 

      Nezhadali, Mohammad; Bhakta, Tuhin; Fossum, Kristian; Mannseth, Trond (Journal article; Peer reviewed, 2023)
      We consider estimation of absolute permeability from inverted seismic data. Large amounts of simultaneous data, such as inverted seismic data, enhance the negative effects of Monte Carlo errors in ensemble-based Data ...
    • Lipid Levels During Adult Lifetime in Men and Women With and Without a Subsequent Incident Myocardial Infarction: A Longitudinal Analysis of Data From the Tromsø Study 1974 to 2016 

      Albrektsen, Grethe; Wilsgaard, Tom; Heuch, Ivar; Løchen, Maja-Lisa; Thelle, Dag Steinar; Njølstad, Inger; Grimsgaard, Sameline; Bønaa, Kaare Harald (Journal article; Peer reviewed, 2023)
      Background The atherosclerotic effect of an adverse lipid profile is assumed to accumulate throughout life, leading to increased risk of myocardial infarction (MI). Still, little is known about age at onset and duration ...
    • Mitochondrial network structure controls cell-to-cell mtDNA variability generated by cell divisions 

      Glastad, Robert Clay; Johnston, Iain (Journal article; Peer reviewed, 2023)
      Mitochondria are highly dynamic organelles, containing vital populations of mitochondrial DNA (mtDNA) distributed throughout the cell. Mitochondria form diverse physical structures in different cells, from cell-wide ...
    • Convergence of Chandrashekar’s Second-Derivative Finite-Volume Approximation 

      Gjesteland, Anita; Svärd, Magnus (Journal article; Peer reviewed, 2023)
      We consider a slightly modified local finite-volume approximation of the Laplacian operator originally proposed by Chandrashekar (Int J Adv Eng Sci Appl Math 8(3):174–193, 2016, https://doi.org/10.1007/s12572-015-0160-z). ...
    • On the formation of coastal rogue waves in water of variable depth 

      Li, Yan; Chabchoub, Amin (Journal article; Peer reviewed, 2023)
      Wave transformation is an intrinsic dynamic process in coastal areas. An essential part of this process is the variation of water depth, which plays a dominant role in the propagation features of water waves, including a ...
    • The aromatic bicomplex for the description of divergence-free aromatic forms and volume-preserving integrators 

      Laurent, Adrien Ange Andre; Mclachlan, Robert I.; Munthe-Kaas, Hans Zanna; Verdier, Olivier Philippe Paul (Journal article; Peer reviewed, 2023)
      Aromatic B-series were introduced as an extension of standard Butcher-series for the study of volume-preserving integrators. It was proven with their help that the only volume-preserving B-series method is the exact flow ...
    • Menopausal hormone therapy, oral contraceptives and risk of chronic low back pain: the HUNT Study 

      Heuch, Ingrid; Heuch, Ivar; Hagen, Knut; Storheim, Kjersti; Zwart, John Anker Henrik (Journal article; Peer reviewed, 2023)
      Background There are indications that use of menopausal hormone therapy (MHT) and oral contraceptives (OC) increases the risk of low back pain (LBP), with higher oestrogen levels involved in the underlying mechanisms. The ...
    • The FluidFlower Validation Benchmark Study for the Storage of CO2 

      Flemisch, Bernd; Nordbotten, Jan Martin; Fernø, Martin; Juanes, Ruben; Both, Jakub Wiktor; Class, Holger; Delshad, Mojdeh; Doster, Florian; Ennis-King, Jonathan; Franc, Jacques; Geiger, Sebastian; Gläser, Dennis; Green, Christopher; Gunning, James; Hajibeygi, Hadi; Jackson, Samuel J.; Jammoul, Mohamad; Karra, Satish; Li, Jiawei; Matthäi, Stephan K.; Miller, Terry; Shao, Qi; Spurin, Catherine; Stauffer, Philip; Tchelepi, Hamdi; Tian, Xiaoming; Viswanathan, Hari; Voskov, Denis; Wang, Yuhang; Wapperom, Michiel; Wheeler, Mary F.; Wilkins, Andrew; Youssef, AbdAllah A.; Zhang, Ziliang (Journal article; Peer reviewed, 2023)
      Successful deployment of geological carbon storage (GCS) requires an extensive use of reservoir simulators for screening, ranking and optimization of storage sites. However, the time scales of GCS are such that no sufficient ...
    • Elliptic curves, ACM bundles and Ulrich bundles on prime Fano threefolds 

      Ciliberto, Ciro; Flamini, Flaminio; Knutsen, Andreas Leopold (Journal article; Peer reviewed, 2023)
      Let X be any smooth prime Fano threefold of degree 2g−2 in Pg+1 , with g ∈ {3, . . . , 10, 12}. We prove that for any integer d satisfying ⌊ g+3 2 ⌋ d g+3 the Hilbert scheme parametriz- ing smooth irreducible elliptic ...
    • Marginalized iterative ensemble smoothers for data assimilation 

      Stordal, Andreas Størksen; Lorentzen, Rolf Johan; Fossum, Kristian (Journal article; Peer reviewed, 2023)
      Data assimilation is an important tool in many geophysical applications. One of many key elements of data assimilation algorithms is the measurement error that determines the weighting of the data in the cost function to ...
    • Covering tour problem with varying coverage: Application to marine environmental monitoring 

      Torabi, Parisa; Oleynik, Anna; Hemmati, Ahmad; Alendal, Guttorm (Journal article; Peer reviewed, 2023)
      In this paper, we present a novel variant of the Covering Tour Problem (CTP), called the Covering Tour Problem with Varying Coverage (CTP-VC). We consider a simple graph 𝐺 = (𝑉 ,𝐸), with a measure of importance assigned ...
    • Machine learning in marine ecology: an overview of techniques and applications 

      Rubbens, Peter; Brodie, Stephanie; Cordier, Tristan; Desto Barcellos, Diogo; DeVos, Paul; Fernandes-Salvador, Jose A; Fincham, Jennifer; Gomes, Alessandra; Handegard, Nils Olav; Howell, Kerry L.; Jamet, Cédric; Kartveit, Kyrre Heldal; Moustahfid, Hassan; Parcerisas, Clea; Politikos, Dimitris V.; Sauzède, Raphaëlle; Sokolova, Maria; Uusitalo, Laura; Van den Bulcke, Laure; van Helmond, Aloysius; Watson, Jordan T.; Welch, Heather; Beltran-Perez, Oscar; Chaffron, Samuel; Greenberg, David S.; Kühn, Bernhard; Kiko, Rainer; Lo, Madiop; Lopes, Rubens M.; Möller, Klas Ove; Michaels, William; Pala, Ahmet; Romagnan, Jean-Baptiste; Schuchert, Pia; Seydi, Vahid; Villasante, Sebastian; Malde, Ketil; Irisson, Jean-Olivier (Journal article; Peer reviewed, 2023)
      Machine learning covers a large set of algorithms that can be trained to identify patterns in data. Thanks to the increase in the amount of data and computing power available, it has become pervasive across scientific ...
    • Numerical Treatment of State-Dependent Permeability in Multiphysics Problems 

      Stefansson, Ivar; Keilegavlen, Eirik (Journal article; Peer reviewed, 2023)
      Constitutive laws relating fluid potentials and fluxes in a nonlinear manner are common in several porous media applications, including biological and reactive flows, poromechanics, and fracture deformation. Compared to ...
    • DarSIA: An Open-Source Python Toolbox for Two-Scale Image Processing of Dynamics in Porous Media 

      Nordbotten, Jan Martin; Benali, Benyamine; Both, Jakub Wiktor; Brattekås, Bergit; Storvik, Erlend; Fernø, Martin (Journal article; Peer reviewed, 2023)
      Understanding porous media flow is inherently a multi-scale challenge, where at the core lies the aggregation of pore-level processes to a continuum, or Darcy-scale, description. This challenge is directly mirrored in image ...
    • A posteriori error estimation and adaptivity for multiple-network poroelasticity 

      Ødegaard, Emilie Eliseussen; Rognes, Marie Elisabeth; Thompson, Travis B. (Journal article; Peer reviewed, 2023)
      The multiple-network poroelasticity (MPET) equations describe deformation and pressures in an elastic medium permeated by interacting fluid networks. In this paper, we (i) place these equations in the theoretical context ...
    • Decay of solitary waves of fractional Korteweg-de Vries type equations 

      Eychenne, Arnaud; Valet, Frederic Fernand Jacques (Journal article; Peer reviewed, 2023)
      We study the solitary waves of fractional Korteweg-de Vries type equations, that are related to the 1- dimensional semi-linear fractional equations: |D|αu + u − f (u) = 0, with α ∈ (0, 2), a prescribed coefficient p∗(α), ...
    • Decay estimates of Green's matrices for discrete-time linear periodic systems 

      Malyshev, Alexander; Sadkane, M. (Journal article; Peer reviewed, 2023)
      We study periodic Lyapunov matrix equations for a general discrete-time linear periodic system Bpxp−Apxp−1=fp, where the matrix coefficients Bp and Ap can be singular. The block coefficients of the inverse operator of the ...