356 research outputs found
Use of programme budgeting and marginal analysis to set priorities for local NHS dental services: learning from the north east of England
Background - Priority setting is necessary where competing demands exceed the finite resources available. The aim of the study was to develop and test a prioritization framework based upon programme budgeting and marginal analysis (PBMA) as a tool to assist National Health Service (NHS) commissioners in their management of resources for local NHS dental services.
Methods - Twenty-seven stakeholders (5 dentists, 8 commissioners and 14 patients) participated in a case-study based in a former NHS commissioning organization in the north of England. Stakeholders modified local decision-making criteria and applied them to a number of different scenarios.
Results - The majority of financial resources for NHS dental services in the commissioning organization studied were allocated to primary care dental practitionersâ contracts in perpetuity, potentially constraining commissionersâ abilities to shift resources. Compiling the programme budget was successful, but organizational flux and difficulties engaging local NHS commissioners significantly impacted upon the marginal analysis phase.
Conclusions - NHS dental practitionersâ contracts resemble budget-silos which do not facilitate local resource reallocation. âContext-specificâ factors significantly challenged the successful implementation and impact of PBMA. A local PBMA champion embedded within commissioning organizations should be considered. Participants found visual depiction of the cost-value ratio helpful during their initial priority setting deliberations
Neutron scattering and molecular correlations in a supercooled liquid
We show that the intermediate scattering function for neutron
scattering (ns) can be expanded naturely with respect to a set of molecular
correlation functions that give a complete description of the translational and
orientational two-point correlations in the liquid. The general properties of
this expansion are discussed with special focus on the -dependence and hints
for a (partial) determination of the molecular correlation functions from
neutron scattering results are given. The resulting representation of the
static structure factor is studied in detail for a model system using
data from a molecular dynamics simulation of a supercooled liquid of rigid
diatomic molecules. The comparison between the exact result for and
different approximations that result from a truncation of the series
representation demonstrates its good convergence for the given model system. On
the other hand it shows explicitly that the coupling between translational
(TDOF) and orientational degrees of freedom (ODOF) of each molecule and
rotational motion of different molecules can not be neglected in the
supercooled regime.Further we report the existence of a prepeak in the
ns-static structure factor of the examined fragile glassformer, demonstrating
that prepeaks can occur even in the most simple molecular liquids. Besides
examining the dependence of the prepeak on the scattering length and the
temperature we use the expansion of into molecular correlation
functions to point out intermediate range orientational order as its principle
origin.Comment: 13 pages, 7 figure
Strong coupling constant from decay within renormalization scheme invariant treatment
We extract a numerical value for the strong coupling constant \alpha_s from
the \tau-lepton decay rate into nonstrange particles. A new feature of our
procedure is the explicit use of renormalization scheme invariance in
analytical form in order to perform the actual analysis in a particular
renormalization scheme. For the reference coupling constant in the
\MSsch-scheme we obtain \alpha_s(M_\tau)= 0.3184 \pm 0.0060_{exp} which
corresponds to \al_s(M_Z)= 0.1184 \pm 0.0007_{exp} \pm 0.0006_{hq mass}. This
new numerical value is smaller than the standard value from -data quoted
in the literature and is closer to \al_s(M_Z)-values obtained from high energy
experiments.Comment: 8 page
Boson gas in a periodic array of tubes
We report the thermodynamic properties of an ideal boson gas confined in an
infinite periodic array of channels modeled by two, mutually perpendicular,
Kronig-Penney delta-potentials. The particle's motion is hindered in the x-y
directions, allowing tunneling of particles through the walls, while no
confinement along the z direction is considered. It is shown that there exists
a finite Bose- Einstein condensation (BEC) critical temperature Tc that
decreases monotonically from the 3D ideal boson gas (IBG) value as the
strength of confinement is increased while keeping the channel's cross
section, constant. In contrast, Tc is a non-monotonic function of
the cross-section area for fixed . In addition to the BEC cusp, the
specific heat exhibits a set of maxima and minima. The minimum located at the
highest temperature is a clear signal of the confinement effect which occurs
when the boson wavelength is twice the cross-section side size. This
confinement is amplified when the wall strength is increased until a
dimensional crossover from 3D to 1D is produced. Some of these features in the
specific heat obtained from this simple model can be related, qualitatively, to
at least two different experimental situations: He adsorbed within the
interstitial channels of a bundle of carbon nanotubes and
superconductor-multistrand-wires NbSn.Comment: 9 pages, 10 figures, submitte
Decay constants, light quark masses and quark mass bounds from light quark pseudoscalar sum rules
The flavor and pseudoscalar correlators are investigated using
families of finite energy sum rules (FESR's) known to be very accurately
satisfied in the isovector vector channel. It is shown that the combination of
constraints provided by the full set of these sum rules is sufficiently strong
to allow determination of both the light quark mass combinations ,
and the decay constants of the first excited pseudoscalar mesons in
these channels. The resulting masses and decay constants are also shown to
produce well-satisfied Borel transformed sum rules, thus providing non-trivial
constraints on the treatment of direct instanton effects in the FESR analysis.
The values of and obtained are in good agreement with the
values implied by recent hadronic decay analyses and the ratios obtained
from ChPT. New light quark mass bounds based on FESR's involving weight
functions which strongly suppress spectral contributions from the excited
resonance region are also presented.Comment: 28 pages, 10 figure
Resummation of the hadronic tau decay width with the modified Borel transform method
A modified Borel transform of the Adler function is used to resum the
hadronic tau decay width ratio. In contrast to the ordinary Borel transform,
the integrand of the Borel integral is renormalization--scale invariant. We use
an ansatz which explicitly accounts for the structure of the leading infrared
renormalon. Further, we use judiciously chosen conformal transformations for
the Borel variable, in order to map sufficiently away from the origin the other
ultraviolet and infrared renormalon singularities. In addition, we apply Pade
approximants for the corresponding truncated perturbation series of the
modified Borel transform, in order to further accelerate the convergence.
Comparing the results with the presently available experimental data on the tau
hadronic decay width ratio, we obtain . These predictions
virtually agree with those of our previous resummations where we used ordinary
Borel transforms instead.Comment: 32 pages, 2 eps-figures, revtex; minor changes in the formulations; a
typo in Eq.(47) corrected; version as appearing in Phys. Rev.
Search for W' bosons decaying to an electron and a neutrino with the D0 detector
This Letter describes the search for a new heavy charged gauge boson W'
decaying into an electron and a neutrino. The data were collected with the D0
detector at the Fermilab Tevatron proton-antiproton Collider at a
center-of-mass energy of 1.96 TeV, and correspond to an integrated luminosity
of about 1 inverse femtobarn. Lacking any significant excess in the data in
comparison with known processes, an upper limit is set on the production cross
section times branching fraction, and a W' boson with mass below 1.00 TeV can
be excluded at the 95% C.L., assuming standard-model-like couplings to
fermions. This result significantly improves upon previous limits, and is the
most stringent to date.Comment: submitted to Phys. Rev. Let
Search for a scalar or vector particle decaying into Zgamma in ppbar collisions at sqrt(s) = 1.96 TeV
We present a search for a narrow scalar or vector resonance decaying into
Zgamma with a subsequent Z decay into a pair of electrons or muons. The data
for this search were collected with the D0 detector at the Fermilab Tevatron
ppbar collider at a center of mass energy sqrt(s) = 1.96 TeV. Using 1.1 (1.0)
fb-1 of data, we observe 49 (50) candidate events in the electron (muon)
channel, in good agreement with the standard model prediction. From the
combination of both channels, we derive 95% C.L. upper limits on the cross
section times branching fraction (sigma x B) into Zgamma. These limits range
from 0.19 (0.20) pb for a scalar (vector) resonance mass of 600 GeV/c^2 to 2.5
(3.1) pb for a mass of 140 GeV/c^2.Comment: Published by Phys. Lett.
Measurement of the Isolated Photon Cross Section in p-pbar Collisions at sqrt{s}=1.96 TeV
The cross section for the inclusive production of isolated photons has been
measured in p anti-p collisions at sqrt{s}=1.96 TeV with the D0 detector at the
Fermilab Tevatron Collider. The photons span transverse momenta 23 to 300 GeV
and have pseudorapidity |eta|<0.9. The cross section is compared with the
results from two next-to-leading order perturbative QCD calculations. The
theoretical predictions agree with the measurement within uncertainties.Comment: 7 pages, 5 figures, submitted to Phys.Lett.
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