3,617 research outputs found
Promoting decentralised and flexible budgets in England: Lessons from the past and future prospects
The UK has traditionally been viewed as a classic example of a unitary state in which central institutions dominate decision making. The recent Labour Government sought to counter this convention through devolution to Scotland, Wales, Northern Ireland and London and administrative decentralization to the English regions. This article examines New Labourâs efforts to promote sub-national policy discretion and fiscal autonomy via the Regional Funding Allocations (RFA) process. Findings are subsequently drawn upon to offer insights into the difficulties the Coalition Government is likely to face in its endeavor to decentralize functions and budgets to local authorities and communities. The paper addresses two central questions (i) Can New Labourâs attempt to promote decentralized and flexible budgets in England be viewed asevidence of a transition to a more fluid, multi-level form of governance? (ii)What lessons can be harnessed from the RFA experience in taking forward the Coalition governmentâs plans to promote fiscal discretion at the sub-national tier? It concludes that there are deep-rooted barriers in Whitehall that may limitthe freedoms and flexibilities pledged to local government and could undermine efforts to decentralize
Carbon monoxide in the solar atmosphere I. Numerical method and two-dimensional models
The radiation hydrodynamic code CO5BOLD has been supplemented with the
time-dependent treatment of chemical reaction networks. Advection of particle
densities due to the hydrodynamic flow field is also included. The radiative
transfer is treated frequency-independently, i.e. grey, so far. The upgraded
code has been applied to two-dimensional simulations of carbon monoxide (CO) in
the non-magnetic solar photosphere and low chromosphere. For this purpose a
reaction network has been constructed, taking into account the reactions which
are most important for the formation and dissociation of CO under the physical
conditions of the solar atmosphere. The network has been strongly reduced to 27
reactions, involving the chemical species H, H2, C, O, CO, CH, OH, and a
representative metal. The resulting CO number density is highest in the cool
regions of the reversed granulation pattern at mid-photospheric heights and
decreases strongly above. There, the CO abundance stays close to a value of 8.3
on the usual logarithmic abundance scale with [H]=12 but is reduced in hot
shock waves which are a ubiquitous phenomenon of the model atmosphere. For
comparison, the corresponding equilibrium densities have been calculated, based
on the reaction network but also under assumption of instantaneous chemical
equilibrium by applying the Rybicki & Hummer (RH) code by Uitenbroek (2001).
Owing to the short chemical timescales, the assumption holds for a large
fraction of the atmosphere, in particular the photosphere. In contrast, the CO
number density deviates strongly from the corresponding equilibrium value in
the vicinity of chromospheric shock waves. Simulations with altered reaction
network clearly show that the formation channel via hydroxide (OH) is the most
important one under the conditions of the solar atmosphere.Comment: 15 pages, 6 figures, final version will contain online materia
Multi-disciplinary Investigation of the Windows of John Thornton, focusing on the Great East Window of York Minster
Twenty-seven samples of glass from panel 2e of John Thorntonâs Great East Window (1405â1408) at York Minster have been analyzed using energy dispersive x-ray analysis in the scanning electron microscope. This paper highlights our findings. Inserts and replacements of early modern and medieval glass have been identifi ed. White (colorless) and colored medieval glass differ significantly in composition, suggesting diff erent sources. Eleven samples of white glass original to the window are identical within analytical error, suggesting they came from the same batch, but the head of Christ is from another panel. Blue and flashed red glass were each the product of more than one batch of melting. Primarily, the condition of the glass is dependent upon silica content. Further investigations of other panels from the Great East Window, and of other windows by Thornton, are ongoing
Viscoelastic response of sonic band-gap materials
A brief report is presented on the effect of viscoelastic losses in a high
density contrast sonic band-gap material of close-packed rubber spheres in air.
The scattering properties of such a material are computed with an on-shell
multiple scattering method, properties which are compared with the lossless
case. The existence of an appreciable omnidirectional gap in the transmission
spectrum, when losses are present, is also reported.Comment: 5 pages, 4 figures, submitted to PR
Performance test of QU-fitting in cosmic magnetism study
QU-fitting is a standard model-fitting method to reconstruct distribution of
magnetic fields and polarized intensity along a line of sight (LOS) from an
observed polarization spectrum. In this paper, we examine the performance of
QU-fitting by simulating observations of two polarized sources located along
the same LOS, varying the widths of the sources and the gap between them in
Faraday depth space, systematically. Markov Chain Monte Carlo (MCMC) approach
is used to obtain the best-fit parameters for a fitting model, and Akaike and
Bayesian Information Criteria (AIC and BIC, respectively) are adopted to select
the best model from four fitting models. We find that the combination of MCMC
and AIC/BIC works fairly well in model selection and estimation of model
parameters in the cases where two sources have relatively small widths and a
larger gap in Faraday depth space. On the other hand, when two sources have
large width in Faraday depth space, MCMC chain tends to be trapped in a local
maximum so that AIC/BIC cannot select a correct model. We discuss the causes
and the tendency of the failure of QU-fitting and suggest a way to improve it.Comment: 8 pages, 9 figures, submitted to MNRA
MVG Mechanism: Differential Privacy under Matrix-Valued Query
Differential privacy mechanism design has traditionally been tailored for a
scalar-valued query function. Although many mechanisms such as the Laplace and
Gaussian mechanisms can be extended to a matrix-valued query function by adding
i.i.d. noise to each element of the matrix, this method is often suboptimal as
it forfeits an opportunity to exploit the structural characteristics typically
associated with matrix analysis. To address this challenge, we propose a novel
differential privacy mechanism called the Matrix-Variate Gaussian (MVG)
mechanism, which adds a matrix-valued noise drawn from a matrix-variate
Gaussian distribution, and we rigorously prove that the MVG mechanism preserves
-differential privacy. Furthermore, we introduce the concept
of directional noise made possible by the design of the MVG mechanism.
Directional noise allows the impact of the noise on the utility of the
matrix-valued query function to be moderated. Finally, we experimentally
demonstrate the performance of our mechanism using three matrix-valued queries
on three privacy-sensitive datasets. We find that the MVG mechanism notably
outperforms four previous state-of-the-art approaches, and provides comparable
utility to the non-private baseline.Comment: Appeared in CCS'1
Regulating Scotland's social landlords: localised resistance to technologies of performance management
Influenced by Foucault's later work on governmentality, this paper explores the regulation of social landlords as a 'technology of performance' concerned with governing the conduct of dispersed welfare agencies and the professionals within them. This is a mode of power that is both voluntary and coercive; it seeks to realise its ambitions not through direct acts of intervention, but by promoting the responsible self-governance of autonomous subjects. Through an analysis of the regulatory framework for social landlords in Scotland, this paper highlights the creation of a performance culture that seeks to mobilise housing organisations to reconcile their local management systems and service provision to external standards, whilst simultaneously wielding punitive interventions for non-compliance. However, housing professionals are not passive in all of this, and indeed, actively challenged and resisted these top-down attempts to govern them at arm's-length
NLTE modeling of Stokes vector center-to-limb variations in the CN violet system
The solar surface magnetic field is connected with and even controls most of
the solar activity phenomena. Zeeman effect diagnostics allow for measuring
only a small fraction of the fractal-like structured magnetic field. The
remaining hidden magnetic fields can only be accessed with the Hanle effect.
Molecular lines are very convenient for applying the Hanle effect diagnostics
thanks to the broad range of magnetic sensitivities in a narrow spectral
region. With the UV version of the Zurich Imaging Polarimeter ZIMPOL II
installed at the 45 cm telescope of the Istituto Ricerche Solari Locarno
(IRSOL), we simultaneously observed intensity and linear polarization
center-to-limb variations in two spectral regions containing the (0,0) and
(1,1) bandheads of the CN B 2 {\Sigma} - X 2 {\Sigma} system. Here we present
an analysis of these observations. We have implemented coherent scattering in
molecular lines into a NLTE radiative transfer code. A two-step approach was
used. First, we separately solved the statistical equilibrium equations and
compute opacities and intensity while neglecting polariza- tion. Then we used
these quantities as input for calculating scattering polarization and the Hanle
effect. We have found that it is impossible to fit the intensity and
polarization simultaneously at different limb angles in the frame- work of
standard 1D modeling. The atmosphere models that provide correct intensity
center-to-limb variations fail to fit linear polar- ization center-to-limb
variations due to lacking radiation field anisotropy. We had to increase the
anisotropy by means of a specially introduced free parameter. This allows us to
successfully interpret our observations. We discuss possible reasons for
underestimating the anisotropy in the 1D modeling.Comment: 15 pages, 10 figures, accepted for publication in
Astronomy&Astrophysic
The solar photospheric abundance of carbon.Analysis of atomic carbon lines with the CO5BOLD solar model
The use of hydrodynamical simulations, the selection of atomic data, and the
computation of deviations from local thermodynamical equilibrium for the
analysis of the solar spectra have implied a downward revision of the solar
metallicity. We are in the process of using the latest simulations computed
with the CO5BOLD code to reassess the solar chemical composition. We determine
the solar photospheric carbon abundance by using a radiation-hydrodynamical
CO5BOLD model, and compute the departures from local thermodynamical
equilibrium by using the Kiel code. We measure equivalent widths of atomic CI
lines on high resolution, high signal-to-noise ratio solar atlases. Deviations
from local thermodynamic equilibrium are computed in 1D with the Kiel code. Our
recommended value for the solar carbon abundance, relies on 98 independent
measurements of observed lines and is A(C)=8.50+-0.06, the quoted error is the
sum of statistical and systematic error. Combined with our recent results for
the solar oxygen and nitrogen abundances this implies a solar metallicity of
Z=0.0154 and Z/X=0.0211. Our analysis implies a solar carbon abundance which is
about 0.1 dex higher than what was found in previous analysis based on
different 3D hydrodynamical computations. The difference is partly driven by
our equivalent width measurements (we measure, on average, larger equivalent
widths with respect to the other work based on a 3D model), in part it is
likely due to the different properties of the hydrodynamical simulations and
the spectrum synthesis code. The solar metallicity we obtain from the CO5BOLD
analyses is in slightly better agreement with the constraints of
helioseismology than the previous 3D abundance results. (Abridged)Comment: Astronomy and Astrophysics, accepte
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