Now showing items 100-119 of 352

  • An Elementary Proof of the Simplicity of the Mathieu Groups M11 and M23 

    Chapman, Robin (Mathematical Association of America (MAA), 1995)
  • 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 ...
  • 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 ...