42,248 research outputs found
Taylorism, targets and the pursuit of quantity and quality by call centre management
The paper locates the rise of the call centre within the context of the development of Taylorist methods and technological change in office work in general. Managerial utilisation of targets to impose and measure employees' quantitative and qualitative performance is analysed in four case-study organisations. The paper concludes that call centre work reflects a pardigmic re-configuration of customer servicing operations, and that the continuing application of Taylorist methods appears likely
The impact of stochastic physics on climate sensitivity in EC-Earth
Stochastic schemes, designed to represent unresolved sub-grid scale
variability, are frequently used in short and medium-range weather forecasts,
where they are found to improve several aspects of the model. In recent years,
the impact of stochastic physics has also been found to be beneficial for the
model's long term climate. In this paper, we demonstrate for the first time
that the inclusion of a stochastic physics scheme can notably affect a model's
projection of global warming, as well as its historical climatological global
temperature. Specifically, we find that when including the 'stochastically
perturbed parametrisation tendencies' scheme (SPPT) in the fully coupled
climate model EC-Earth v3.1, the predicted level of global warming between 1850
and 2100 is reduced by 10% under an RCP8.5 forcing scenario. We link this
reduction in climate sensitivity to a change in the cloud feedbacks with SPPT.
In particular, the scheme appears to reduce the positive low cloud cover
feedback, and increase the negative cloud optical feedback. A key role is
played by a robust, rapid increase in cloud liquid water with SPPT, which we
speculate is due to the scheme's non-linear interaction with condensation.Comment: Under review in Journal of Geophysical Research: Atmosphere
Analytic solutions of the magnetic annihilation and reconnection problems. I. Planar flow profiles
The phenomena of steady-state magnetic annihilation and reconnection in the vicinity of magnetic nulls are considered. It is shown that reconnective solutions can be derived by superposing the velocity and magnetic fields of simple magnetic annihilation models. These solutions contain most of the previous models for magnetic merging and reconnection, as well as introducing several new solutions. The various magnetic dissipation mechanisms are classified by examining the scaling of the Ohmic diffusion rate with plasma resistivity. Reconnection solutions generally allow more favorable "fast" dissipation scalings than annihilation models. In particular, reconnection models involving the advection of planar field components have the potential to satisfy the severe energy release requirements of the solar flare. The present paper is mainly concerned with magnetic fields embedded in strictly planar flows—a discussion of the more complicated three-dimensional flow patterns is presented in Part II [Phys. Plasmas 4, 110 (1997)]
The shape of primordial non-Gaussianity and the CMB bispectrum
We present a set of formalisms for comparing, evolving and constraining
primordial non-Gaussian models through the CMB bispectrum. We describe improved
methods for efficient computation of the full CMB bispectrum for any general
(non-separable) primordial bispectrum, incorporating a flat sky approximation
and a new cubic interpolation. We review all the primordial non-Gaussian models
in the present literature and calculate the CMB bispectrum up to l <2000 for
each different model. This allows us to determine the observational
independence of these models by calculating the cross-correlation of their CMB
bispectra. We are able to identify several distinct classes of primordial
shapes - including equilateral, local, warm, flat and feature (non-scale
invariant) - which should be distinguishable given a significant detection of
CMB non-Gaussianity. We demonstrate that a simple shape correlator provides a
fast and reliable method for determining whether or not CMB shapes are well
correlated. We use an eigenmode decomposition of the primordial shape to
characterise and understand model independence. Finally, we advocate a
standardised normalisation method for based on the shape
autocorrelator, so that observational limits and errors can be consistently
compared for different models.Comment: 32 pages, 20 figure
Primordial non-Gaussianity and the CMB bispectrum
We present a new formalism, together with efficient numerical methods, to
directly calculate the CMB bispectrum today from a given primordial bispectrum
using the full linear radiation transfer functions. Unlike previous analyses
which have assumed simple separable ansatze for the bispectrum, this work
applies to a primordial bispectrum of almost arbitrary functional form, for
which there may have been both horizon-crossing and superhorizon contributions.
We employ adaptive methods on a hierarchical triangular grid and we establish
their accuracy by direct comparison with an exact analytic solution, valid on
large angular scales. We demonstrate that we can calculate the full CMB
bispectrum to greater than 1% precision out to multipoles l<1800 on reasonable
computational timescales. We plot the bispectrum for both the superhorizon
('local') and horizon-crossing ('equilateral') asymptotic limits, illustrating
its oscillatory nature which is analogous to the CMB power spectrum
Gravitational wave energy spectrum of a parabolic encounter
We derive an analytic expression for the energy spectrum of gravitational
waves from a parabolic Keplerian binary by taking the limit of the Peters and
Matthews spectrum for eccentric orbits. This demonstrates that the location of
the peak of the energy spectrum depends primarily on the orbital periapse
rather than the eccentricity. We compare this weak-field result to strong-field
calculations and find it is reasonably accurate (~10%) provided that the
azimuthal and radial orbital frequencies do not differ by more than ~10%. For
equatorial orbits in the Kerr spacetime, this corresponds to periapse radii of
rp > 20M. These results can be used to model radiation bursts from compact
objects on highly eccentric orbits about massive black holes in the local
Universe, which could be detected by LISA.Comment: 5 pages, 3 figures. Minor changes to match published version; figure
1 corrected; references adde
Survey of J=0,1 mesons in a Bethe-Salpeter approach
The Bethe-Salpeter equation is used to comprehensively study mesons with
J=0,1 and equal-mass constituents for quark masses from the chiral limit to the
b-quark mass. The survey contains masses of the ground states in all
corresponding J^{PC} channels including those with "exotic" quantum numbers.
The emphasis is put on each particular state's sensitivity to the low- and
intermediate-momentum, i.e., long-range part of the strong interaction.Comment: 8 pages, 4 figure
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