Now showing items 330-349 of 1108

  • 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 ...
  • Exact harmonic coefficients for a magnetic ring head 

    Wilton, David T.; Middleton, Barry K.; Aziz, Mustafa M. (IEEE, 1999)
    The magnetic field of a ring head has been analyzed by Westmijze [1953], using a conformal mapping, and by Fan [1961], using Fourier techniques. Here these methods are reexamined and combined to give, for the first time, ...
  • Exactly-solvable problems for two-dimensional excitons 

    Parfitt, D.G.W.; Portnoi, M.E. (Nova Science Publishers, 2004)
    Several problems in mathematical physics relating to excitons in two dimensions are considered. First, a fascinating numerical result from a theoretical treatment of screened excitons stimulates a re-evaluation of the ...
  • 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 ...
  • Excitation and Imaging of Precessional Modes in Soft-Magnetic Squares 

    Neudert, A.; Keatley, Paul Steven; Kruglyak, V.V.; McCord, Jeffrey; Hicken, R.J. (Institute of Electrical and Electronics Engineers (IEEE), 2008)
    We investigated the high-frequency modes of 40 mum wide, 160 nm thick Fe 70Co8B12Si10 squares using time-resolved scanning Kerr microscopy. Two modes were identified using pulsed field excitation while the spatial character ...
  • Excitation of propagating spin waves with global uniform microwave fields 

    Au, Y.; Davison, T.; Ahmad, E.; Keatley, Paul Steven; Hicken, R.J.; Kruglyak, V.V. (American Institute of Physics, 2011)
    We demonstrate a magnonic architecture that converts global free-space uniform microwaves into spin waves propagating in a stripe magnonic waveguide. The architecture is based upon dispersion mismatch between the narrow ...
  • Excitation of remarkably nondispersive surface plasmons on a nondiffracting, dual-pitch metal grating 

    Hibbins, Alastair P.; Sambles, J. Roy; Lawrence, Christopher R. (American Institute of Physics, 2002)
    A nondiffracting metallic lamellar grating formed from three equally spaced grooves per repeat period, with one being slightly shallower than the other two is examined at microwave frequencies. When filled with a slightly ...
  • Exciton and electron-hole plasma formation dynamics in ZnO 

    Hendry, Euan; Koeberg, Mattijs; Bonn, Mischa (American Physical Society, 2007)
    We employ optical pump-THz probe measurements to study the formation of excitons and electron-hole plasmas following photogeneration of a hot electron-hole gas in the direct gap semiconductor zinc oxide. Below the Mott ...
  • Exciton storage in a nanoscale Aharonov-Bohm ring with electric field tuning 

    Fischer, Andrea M.; Campo, Vivaldo L.; Portnoi, M.E.; Römer, Rudolf A. (American Physical Society, 2009)
    We study analytically the optical properties of a simple model for an electron-hole pair on a ring subjected to perpendicular magnetic flux and in-plane electric field. We show how to tune this excitonic system from optically ...
  • Excitons and interband terahertz transitions in narrow-gap carbon nanotubes 

    Portnoi, M.E.; Downing, C.A.; Hartmann, Richard R.; Shelykh, I.A. (Institute of Electrical and Electronics Engineers (IEEE), 2013)
    We show, via a solution of the quasi-one-dimensional two-body problem applied to a Dirac system, that excitonic effects suppress the one-dimensional Van Hove singularity in single-walled carbon nanotubes with narrow band gaps.
  • Excitons in narrow-gap carbon nanotubes 

    Hartmann, Richard R.; Shelykh, I.A.; Portnoi, M.E. (American Physical Society, 2011)
    We calculate the exciton binding energy in single-walled carbon nanotubes with narrow band gaps, accounting for the quasirelativistic dispersion of electrons and holes. Exact analytical solutions of the quantum relativistic ...
  • Exospheric models for the X-ray emission from single Wolf-Rayet stars 

    Ignace, R.; Oskinova, L.M.; Foullon, Claire (Oxford University Press / Royal Astronomical Society, 2000)
    We review existing ROSAT detections of single Galactic Wolf-Rayet (WR) stars and develop wind models to interpret the X-ray emission. The ROSAT data, consisting of bandpass detections from the ROSAT All-Sky Survey (RASS) ...