Now showing items 77-96 of 297

  • Diffusion and the formation of vorticity staircases in randomly strained two-dimensional vortices 

    Turner, M.R.; Bassom, Andrew P.; Gilbert, Andrew D. (Cambridge University Press, 2009)
    The spreading and diffusion of two-dimensional vortices subject to weak external random strain fields is examined. The response to such a field of given angular frequency depends on the profile of the vortex and can be ...
  • Digital clocks: simple Boolean models can quantitatively describe circadian systems 

    Akman, Ozgur E.; Watterson, Steven; Parton, Andrew; Binns, Nigel; Millar, Andrew J.; Ghazal, Peter (Royal Society, 2012)
    The gene networks that comprise the circadian clock modulate biological function across a range of scales, from gene expression to performance and adaptive behaviour. The clock functions by generating endogenous rhythms ...
  • Disciplines, geography, and gender in the framing of climate change 

    O'Neill, Saffron J.; Hulme, Mike; Turnpenny, John; Screen, James A. (American Meteorological Society, 2010)
    No abstract available
  • Discrete computation using a perturbed heteroclinic network 

    Ashwin, Peter; Borresen, Jon (Elsevier, 2005)
    Transient synchronization into clusters appears in many biological and physical systems and seems to be important for computation within neural systems. In this paper we show how one can robustly and effectively perform ...
  • Dissipative structures in a nonlinear dynamo 

    Gilbert, Andrew D.; Ponty, Y.; Zheligovsky, V. (Taylor & Francis, 2010-12-02)
    This paper considers magnetic field generation by a fluid flow in a system referred to as the Archontis dynamo: a steady nonlinear magnetohydrodynamic (MHD) state is driven by a prescribed body force. The field and flow become ...
  • Dramatic interannual changes of perennial Arctic sea ice linked to abnormal summer storm activity 

    Screen, James A.; Simmonds, Ian; Keay, Kevin (American Geophysical Union, 2011)
    The perennial (September) Arctic sea ice cover exhibits large interannual variability, with changes of over a million square kilometers from one year to the next. Here we explore the role of changes in Arctic cyclone ...
  • Drift of scroll waves in thin layers caused by thickness features: asymptotic theory and numerical simulations 

    Biktasheva, I. V.; Dierckx, H.; Biktashev, V. N. (American Physical Society, 2015)
    A scroll wave in a very thin layer of excitable medium is similar to a spiral wave, but its behavior is affected by the layer geometry. We identify the effect of sharp variations of the layer thickness, which is separate ...
  • Dynamics of coupled cell networks: synchrony, heteroclinic cycles and inflation 

    Aguiar, M.; Ashwin, Peter; Dias, A.; Field, Michael (Springer Verlag, 2011)
    We consider the dynamics of small networks of coupled cells. We usually assume asymmetric inputs and no global or local symmetries in the network and consider equivalence of networks in this setting; that is, when two ...
  • Dynamics of filaments of scroll waves 

    Biktashev, V. N.; Biktasheva, I. V. (World Scientific, 2014)
    The following sections are included: A Brief History and Motivation; Wave-Particle Duality of Spiral Waves; Perturbative Dynamics of Scrolls, and Tension of Filaments; Scroll Wave Turbulence; Rigidity of Scroll Filaments: ...
  • Dynamics of the nearly parametric pendulum 

    Horton, B.; Sieber, J.; Thompson, J.M.; Wiercigroch, M. (Elsevier, 2011)
  • Dynamics of two laterally coupled semiconductor lasers: strong- and weak-coupling theory. 

    Erzgraber, H.; Wieczorek, Sebastian; Krauskopf, Bernd (American Physical Society, 2008)
    The stability and nonlinear dynamics of two semiconductor lasers coupled side to side via evanescent waves are investigated by using three different models. In the composite-cavity model, the coupling between the lasers ...
  • Dynamics on networks of cluster states for globally coupled phase oscillators 

    Ashwin, Peter; Orosz, Gábor; Wordsworth, John; Townley, Stuart (Society for Industrial and Applied Mathematics, 2007)
    Systems of globally coupled phase oscillators can have robust attractors that are heteroclinic networks. We investigate such a heteroclinic network between partially synchronized states where the phases cluster into three ...
  • Dynamo action in the ABC flows using symmetries 

    Jones, Samuel Edward; Gilbert, Andrew D. (Taylor & Francis, 2013-09-25)
    This paper concerns kinematic dynamo action by the 1:1:1 ABC flow, in the highly conducting limit of large magnetic Reynolds number Rm. The flow possesses 24 symmetries, with a symmetry group isomorphic to the group O24 ...
  • Effective diffusion of scalar fields in a chaotic flow 

    Turner, M. R.; Gilbert, Andrew D.; Thuburn, John (American Institute of Physics, 2008)
    The advection of a tracer field in a fluid flow can create complex scalar structures and increase the effect of weak diffusion by orders of magnitude. One tool to quantify this is to measure the flux of scalar across contour ...
  • Effects of frozen soil on soil temperature, spring infiltration, and runoff: results from the PILPS 2(d) experiment at Valdai, Russia 

    Luo, Lifeng; Robock, Alan; Vinnikov, Konstantin Y.; Schlosser, C. Adam; Slater, Andrew G.; Boone, Aaron; Braden, Harald; Cox, Peter M.; De Rosnay, Patricia; Dickinson, Robert E.; Dai, Yongjiu; Duan, Qingyun; Etchevers, Pierre; Henderson-Sellers, Ann; Gedney, Nicola; Gusev, Yevgeniy M.; Habets, Florence; Kim, Jinwon; Kowalczyk, Eva; Mitchell, Ken; Nasonova, Olga N.; Noilhan, Joel; Pitman, Andrew; Schaake, John; Shmakin, Andrey B.; Smirnova, Tatiana G.; Wetzel, Peter; Xue, Yongkang; Yang, Zong-Liang; Zeng, Qing-Cun (American Meteorological Society, 2009-12-18)
    The Project for Intercomparison of Land-Surface Parameterization Schemes phase 2(d) experiment at Valdai, Russia, offers a unique opportunity to evaluate land surface schemes, especially snow and frozen soil parameterizations. ...
  • Elevated risk of stillbirth in males: systematic review and meta-analysis of more than 30 million births 

    Mondal, Debapriya; Galloway, Tamara S.; Bailey, Trevor C.; Mathews, Fiona (BioMed Central, 2014)
    BACKGROUND: Stillbirth rates have changed little over the last decade, and a high proportion of cases are unexplained. This meta-analysis examined whether there are inequalities in stillbirth risks according to sex. METHODS: ...
  • Elliptic behaviour in the sawtooth standard map 

    Ashwin, Peter (Elsevier, 1997)
    This paper examines the standard map with sawtooth nonlinearity when the eigenvalues of the Jacobian lie on the unit circle. This is an area-preserving map of the torus to itself that is linear except on a line on which ...
  • Emergence and maintenance of functional modules in signaling pathways 

    Soyer, Orkun S. (BioMed Central, 2007)
    Background: While detection and analysis of functional modules in biological systems have received great attention in recent years, we still lack a complete understanding of how such modules emerge. One theory is that ...
  • Encoding via conjugate symmetries of slow oscillations for globally coupled oscillators 

    Ashwin, Peter; Borresen, Jon (American Physical Society, 2004)
    We study properties of the dynamics underlying slow cluster oscillations in two systems of five globally coupled oscillators. These slow oscillations are due to the appearance of structurally stable heteroclinic connections ...
  • Energy-crossing number relations for braided magnetic fields 

    Berger, M.A. (American Physical Society, 1993)
    This Letter derives lower bounds on the energy of braided magnetic fields, based on crossing number techniques pioneered by Freedman and He. Mean crossing numbers are defined for magnetic fields inside a cylinder; for ...