387 research outputs found

    The mean velocity of two-state models of molecular motor

    Full text link
    The motion of molecular motor is essential to the biophysical functioning of living cells. In principle, this motion can be regraded as a multiple chemical states process. In which, the molecular motor can jump between different chemical states, and in each chemical state, the motor moves forward or backward in a corresponding potential. So, mathematically, the motion of molecular motor can be described by several coupled one-dimensional hopping models or by several coupled Fokker-Planck equations. To know the basic properties of molecular motor, in this paper, we will give detailed analysis about the simplest cases: in which there are only two chemical states. Actually, many of the existing models, such as the flashing ratchet model, can be regarded as a two-state model. From the explicit expression of the mean velocity, we find that the mean velocity of molecular motor might be nonzero even if the potential in each state is periodic, which means that there is no energy input to the molecular motor in each of the two states. At the same time, the mean velocity might be zero even if there is energy input to the molecular motor. Generally, the velocity of molecular motor depends not only on the potentials (or corresponding forward and backward transition rates) in the two states, but also on the transition rates between the two chemical states

    Crisis-Induced Social Conflicts in the European Union – Trade Union Perspectives: The Emergence of 'Crisis Corporatism' or the Failure of Corporatist Arrangements?

    Get PDF
    This paper aims to explore the role of labour and trade unions in the repeated shifts of crisis phenomena over the past years. It addresses the question why, confronted with the very profoundness of the crisis, they have failed to develop politically relevant and socially progressive strategies so far. The presented argument not only refers to structural power relations but in particular to the political struggles and processes in which more far-reaching ambitions have been knocked into shape. In that context, the focus is above all on economic stimulus packages, financial market regulation, and current budget consolidation. The paper will be organised as follows: It will start with some general problems of trade unions in generating sufficient power and organisational capacities against the background of the unfolding crisis within the European Union (EU). The next section empirically highlights these developments by discussing the cases of Germany, France, and Spain. The paper then concludes highlighting common challenges and chances, but also the difficulties to form new progressive European alliances

    Implementation of mean-timing and subsequent logic functions on an FPGA

    Full text link
    This article describes the implementation of a mean-timer and coincidence logic on a Virtex-5 FPGA for trigger purposes in a particle physics experiment. The novel feature is that the mean-timing and the coincidence logic are not synchronized with a clock which allows for a higher resolution of approximately 400 ps, not limited by a clock frequency.Comment: 15 pages, 11 figure

    The effects of financialisation and financial development on investment: Evidence from firm-level data in Europe

    Get PDF
    In this paper we estimate the effects of financialization on physical investment in selected western European countries using panel data based on the balance-sheets of publicly listed non-financial companies (NFCs) supplied by Worldscope for the period 1995-2015. We find robust evidence of an adverse effect of both financial payments (interests and dividends) and financial incomes on investment in fixed assets by the NFCs. This finding is robust for both the pool of all Western European firms and single country estimations. The negative impacts of financial incomes are non-linear with respect to the companies’ size: financial incomes crowd-out investment in large companies, and have a positive effect on the investment of only small, relatively more credit-constrained companies. Moreover, we find that a higher degree of financial development is associated with a stronger negative effect of financial incomes on companies’ investment. This finding challenges the common wisdom on ‘finance-growth nexus’. Our findings support the ‘financialization thesis’ that the increasing orientation of the non-financial sector towards financial activities is ultimately leading to lower physical investment, hence to stagnant or fragile growth, as well as long term stagnation in productivity

    Noncommutative Burgers Equation

    Get PDF
    We present a noncommutative version of the Burgers equation which possesses the Lax representation and discuss the integrability in detail. We find a noncommutative version of the Cole-Hopf transformation and succeed in the linearization of it. The linearized equation is the (noncommutative) diffusion equation and exactly solved. We also discuss the properties of some exact solutions. The result shows that the noncommutative Burgers equation is completely integrable even though it contains infinite number of time derivatives. Furthermore, we derive the noncommutative Burgers equation from the noncommutative (anti-)self-dual Yang-Mills equation by reduction, which is an evidence for the noncommutative Ward conjecture. Finally, we present a noncommutative version of the Burgers hierarchy by both the Lax-pair generating technique and the Sato's approach.Comment: 24 pages, LaTeX, 1 figure; v2: discussions on Ward conjecture, Sato theory and the integrability added, references added, version to appear in J. Phys.

    Interaction of Noncommutative Plane Waves in 2+1 Dimensions

    Get PDF
    In this paper the interaction of extended waves in a noncommutative modified 2+1 dimensional U(2) sigma model are studied. Using the dressing method, we construct an explicit two-wave solution of the noncommutative field equation. The scattering of these waves and large time factorization are discussed.Comment: 12 pages, 4 figures, latex; V.2: two references adde

    Managerial power in the German model: the case of Bertelsmann and the antecedents of neoliberalism

    Get PDF
    Our article extends the research on authoritarian neoliberalism to Germany, through a history of the Bertelsmann media corporation – sponsor and namesake of Germany’s most influential neoliberal think-tank. Our article makes three conceptual moves. Firstly, we argue that conceptualizing German neoliberalism in terms of an ‘ordoliberal paradigm’ is of limited use in explaining the rise and fall of Germany’s distinctive socio-economic model (Modell Deutschland). Instead, we locate the origins of authoritarian tendencies in the corporate power exercised by managers rather than in the power of state-backed markets imagined by ordoliberals. Secondly, we focus on the managerial innovations of Bertelsmann as a key actor enmeshed with Modell Deutschland. We show that the adaptation of business management practices of an endogenous ‘Cologne School’ empowered Bertelsmann’s postwar managers to overcome existential crises and financial constraints despite being excluded from Germany’s corporate support network. Thirdly, we argue that their further development in the 1970s also enabled Bertelsmann to curtail and circumvent the forms of labour representation associated with Modell Deutschland. Inspired by cybernetic management theories that it used to limit and control rather than revive market competition among its workforce, Bertelsmann began to act and think outside the postwar settlement between capital and labour before the settlement’s hotly-debated demise since the 1990s

    Spin alignment and violation of the OZI rule in exclusive ω\omega and ϕ\phi production in pp collisions

    Get PDF
    Exclusive production of the isoscalar vector mesons ω\omega and ϕ\phi is measured with a 190 GeV/c/c proton beam impinging on a liquid hydrogen target. Cross section ratios are determined in three intervals of the Feynman variable xFx_{F} of the fast proton. A significant violation of the OZI rule is found, confirming earlier findings. Its kinematic dependence on xFx_{F} and on the invariant mass MpVM_{p\mathrm{V}} of the system formed by fast proton pfastp_\mathrm{fast} and vector meson VV is discussed in terms of diffractive production of pfastVp_\mathrm{fast}V resonances in competition with central production. The measurement of the spin density matrix element ρ00\rho_{00} of the vector mesons in different selected reference frames provides another handle to distinguish the contributions of these two major reaction types. Again, dependences of the alignment on xFx_{F} and on MpVM_{p\mathrm{V}} are found. Most of the observations can be traced back to the existence of several excited baryon states contributing to ω\omega production which are absent in the case of the ϕ\phi meson. Removing the low-mass MpVM_{p\mathrm{V}} resonant region, the OZI rule is found to be violated by a factor of eight, independently of xFx_\mathrm{F}.Comment: 23 pages, 13 figures and 5 table

    Prime movers : mechanochemistry of mitotic kinesins

    Get PDF
    Mitotic spindles are self-organizing protein machines that harness teams of multiple force generators to drive chromosome segregation. Kinesins are key members of these force-generating teams. Different kinesins walk directionally along dynamic microtubules, anchor, crosslink, align and sort microtubules into polarized bundles, and influence microtubule dynamics by interacting with microtubule tips. The mechanochemical mechanisms of these kinesins are specialized to enable each type to make a specific contribution to spindle self-organization and chromosome segregation

    Measurement of the charged-pion polarisability

    Get PDF
    The COMPASS collaboration at CERN has investigated pion Compton scattering, πγπγ\pi^-\gamma\rightarrow \pi^-\gamma, at centre-of-mass energy below 3.5 pion masses. The process is embedded in the reaction πNiπγ  Ni\pi^-\mathrm{Ni}\rightarrow\pi^-\gamma\;\mathrm{Ni}, which is initiated by 190\,GeV pions impinging on a nickel target. The exchange of quasi-real photons is selected by isolating the sharp Coulomb peak observed at smallest momentum transfers, Q2<0.0015Q^2<0.0015\,(GeV/cc)2^2. From a sample of 63\,000 events the pion electric polarisability is determined to be $\alpha_\pi\ =\ (\,2.0\ \pm\ 0.6_{\mbox{\scriptsize stat}}\ \pm\ 0.7_{\mbox{\scriptsize syst}}\,) \times 10^{-4}\,\mbox{fm}^3undertheassumption under the assumption \alpha_\pi=-\beta_\pi$, which relates the electric and magnetic dipole polarisabilities. It is the most precise measurement of this fundamental low-energy parameter of strong interaction, that has been addressed since long by various methods with conflicting outcomes. While this result is in tension with previous dedicated measurements, it is found in agreement with the expectation from chiral perturbation theory. An additional measurement replacing pions by muons, for which the cross-section behavior is unambigiously known, was performed for an independent estimate of the systematic uncertainty.Comment: Published version: 9 pages, 3 figures, 1 tabl
    corecore