Now showing items 105-124 of 357

  • 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 ...
  • Envelope quasisolitons in dissipative systems with cross-diffusion 

    Biktashev, V. N.; Tsyganov, M. A. (American Physical Society, 2011)
    We consider two-component nonlinear dissipative spatially extended systems of reaction-cross-diffusion type. Previously, such systems were shown to support "quasisoliton" pulses, which have a fixed stable structure but can ...
  • Equitability revisited: why the 'equitable threat score' is not equitable 

    Hogan, Robin J.; Ferro, Christopher A.T.; Jolliffe, Ian T.; Stephenson, David B. (American Meteorological Society, 2010)
    In the forecasting of binary events, verification measures that are “equitable” were defined by Gandin and Murphy to satisfy two requirements: 1) they award all random forecasting systems, including those that always issue ...
  • Erroneous arctic temperature trends in the ERA-40 reanalysis: A closer look 

    Screen, James A.; Simmonds, Ian (American Meteorological Society, 2011)
    Atmospheric reanalyses can be useful tools for examining climate variability and change; however, they must be used cautiously because of time-varying biases that can induce artificial trends. This study explicitly documents ...
  • Error bounds in the gap metric for dissipative balanced approximations 

    Guiver, Chris; Opmeer, Mark R. (Elsevier, 2013)
    We derive an error bound in the gap metric for positive real balanced truncation and positive real singular perturbation approximation. We prove these results by working in the context of dissipative driving-variable ...
  • Estimates of past and future ozone trends from multi-model simulations using a flexible smoothing spline methodology 

    Scinocca, John F.; Stephenson, David B.; Bailey, Trevor C.; Austin, John (American Geophysical Union, 2010)
    A novel additive model analysis of multimodel trends is presented. The approach is motivated by, and particularly suited to, the analysis of multimodel time series of varying length. This Time series Additive Model (TSAM) ...
  • The evaluation of directionally writhing polymers 

    Prior, C.B.; Berger, M.A. (arXiv.org, 2010)
    We discuss the appropriate techniques for modelling the geometry of open ended elastic polymer molecules. The molecule is assumed to have fixed endpoints on a boundary surface. In particular we discuss the concept of the ...
  • Event collisions in systems with delayed switches 

    Sieber, J.; Kowalczyk, P. (Elsevier, 2006)
    We study dynamical systems that switch between two different vector fields depending on a discrete variable. If the two vector fields have linearly unstable fixed points and the switch is subject to a hysteresis and to a ...
  • The evolution of connectivity in metabolic networks. 

    Pfeiffer, Thomas; Soyer, Orkun S.; Bonhoeffer, Sebastian (Public Library of Science, 2005)
    Processes in living cells are the result of interactions between biochemical compounds in highly complex biochemical networks. It is a major challenge in biology to understand causes and consequences of the specific design ...
  • Evolution of Kelvin-Helmholtz activity on the dusk flank magnetopause 

    Foullon, Claire; Farrugia, Charles J.; Fazakerley, Andrew; Owen, Christopher J.; Gratton, F.T.; Torbert, R.B. (American Geophysical Union (AGU), 2008)
    Our purpose is to characterize the evolution of the magnetopause Kelvin-Helmholtz (KH) wave activity with changes in thickness of the adjacent boundary layer, geomagnetic latitude and interplanetary magnetic field (IMF) ...
  • Evolution of response dynamics underlying bacterial chemotaxis 

    Soyer, Orkun S.; Goldstein, Richard A. (BioMed Central, 2011)
    Background: The ability to predict the function and structure of complex molecular mechanisms underlying cellular behaviour is one of the main aims of systems biology. To achieve it, we need to understand the evolutionary ...
  • Evolution of spiral and scroll waves of excitation in a mathematical model of ischaemic border zone 

    Biktashev, V. N.; Biktasheva, I. V.; Sarvazyan, N. A. (Public Library of Science, 2011)
    Abnormal electrical activity from the boundaries of ischemic cardiac tissue is recognized as one of the major causes in generation of ischemia-reperfusion arrhythmias. Here we present theoretical analysis of the waves of ...
  • Evolution of taxis responses in virtual bacteria: non-adaptive dynamics. 

    Goldstein, Richard A.; Soyer, Orkun S. (Public Library of Science, 2008)
    Bacteria are able to sense and respond to a variety of external stimuli, with responses that vary from stimuli to stimuli and from species to species. The best-understood is chemotaxis in the model organism Escherichia ...
  • Evolution of the L1 halo family in the radial solar sail circular restricted three-body problem 

    Verrier, Patricia; Waters, Thomas; Sieber, J. (Springer Verlag, 2014)
    We present a detailed investigation of the dramatic changes that occur in the L1 halo family when radiation pressure is introduced into the Sun–Earth circular restricted three-body problem (CRTBP). This photo-gravitational ...
  • The evolution of writhe in kink-unstable flux ropes and erupting filaments 

    Torok, T.; Kliem, B.; Berger, M.A.; Linton, M.G.; Demoulin, P.; van Driel-Gesztelyi, L. (IOP Publishing, 2014)
    The helical kink instability of a twisted magnetic flux tube has been suggested as a trigger mechanism for solar filament eruptions and coronal mass ejections (CMEs). In order to investigate if estimations of the pre-emptive ...
  • Evolution under Fluctuating Environments Explains Observed Robustness in Metabolic Networks 

    Soyer, Orkun S.; Pfeiffer, Thomas (Public Library of Science, 2010)
    A high level of robustness against gene deletion is observed in many organisms. However, it is still not clear which biochemical features underline this robustness and how these are acquired during evolution. One hypothesis, ...
  • Evolving Bayesian Emulators for Structured Chaotic Time Series, with application to large climate models 

    Williamson, Daniel; Blaker, Adam T. (Society for Industrial and Applied Mathematics and American Statistical Association, 2014)
    We develop Bayesian dynamic linear model Gaussian processes for emulation of time series output for computer models that may exhibit chaotic behavior, but where this behavior retains some underlying structure. The statistical ...
  • An exact solution for arbitrarily rotating gaseous polytropes with index unity 

    Kong, Dali; Zhang, Keke; Schubert, Gerald (Oxford University Press for Royal Astronomical Society, 2015)
    Many gaseous planets and stars are rapidly rotating and can be approximately described by a polytropic equation of state with index unity.We present the first exact analytic solution, under the assumption of the oblate ...
  • Excitability in ramped systems: the compost-bomb instability 

    Wieczorek, Sebastian; Ashwin, Peter; Luke, Catherine M.; Cox, Peter M. (Royal Society, 2011)
    The paper studies a novel excitability type where a large excitable response appears when a system’s parameter is varied gradually, or ramped, above some critical rate. This occurs even though there is a (unique) stable ...