2,355 research outputs found
Numerical Implementation of Harmonic Polylogarithms to Weight w = 8
We present the FORTRAN-code HPOLY.f for the numerical calculation of harmonic
polylogarithms up to w = 8 at an absolute accuracy of
or better. Using algebraic and argument relations the numerical representation
can be limited to the range . We provide replacement
files to map all harmonic polylogarithms to a basis and the usual range of
arguments to the above interval analytically. We also
briefly comment on a numerical implementation of real valued cyclotomic
harmonic polylogarithms.Comment: 19 pages LATEX, 3 Figures, ancillary dat
Speed control with low armature loss for very small sensorless brushed DC motors
A method for speed control of brushed dc motors is presented. It is particularly applicable to motors with armatures of less than 1 cm3. Motors with very small armatures are difficult to control using the usual pulsewidth-modulation (PWM) approach and are apt to overheat if so driven. The technique regulates speed via the back electromotive force but does not require current-discontinuous drives. Armature heating in small motors under PWM drive is explained and quantified. The method is verified through simulation and measurement. Control is improved, and armature losses are minimized. The method can expect to find application in miniature mechatronic equipment
A safer place for patients: learning to improve patient safety
1 Every day over one million people are treated
successfully by National Health Service (NHS) acute,
ambulance and mental health trusts. However, healthcare
relies on a range of complex interactions of people,
skills, technologies and drugs, and sometimes things do
go wrong. For most countries, patient safety is now the
key issue in healthcare quality and risk management.
The Department of Health (the Department) estimates
that one in ten patients admitted to NHS hospitals will be
unintentionally harmed, a rate similar to other developed
countries. Around 50 per cent of these patient safety
incidentsa could have been avoided, if only lessons from
previous incidents had been learned.
2
There are numerous stakeholders with a role in
keeping patients safe in the NHS, many of whom require
trusts to report details of patient safety incidents and near
misses to them (Figure 2). However, a number of previous
National Audit Office reports have highlighted concerns
that the NHS has limited information on the extent and
impact of clinical and non-clinical incidents and trusts need
to learn from these incidents and share good practice across
the NHS more effectively (Appendix 1).
3 In 2000, the Chief Medical Officerâs report An
organisation with a memory
1
, identified that the key
barriers to reducing the number of patient safety incidents
were an organisational culture that inhibited reporting and
the lack of a cohesive national system for identifying and
sharing lessons learnt.
4 In response, the Department published Building a
safer NHS for patients3 detailing plans and a timetable
for promoting patient safety. The goal was to encourage
improvements in reporting and learning through the
development of a new mandatory national reporting
scheme for patient safety incidents and near misses. Central
to the plan was establishing the National Patient Safety
Agency to improve patient safety by reducing the risk of
harm through error. The National Patient Safety Agency was
expected to: collect and analyse information; assimilate
other safety-related information from a variety of existing
reporting systems; learn lessons and produce solutions.
5 We therefore examined whether the NHS has
been successful in improving the patient safety culture,
encouraging reporting and learning from patient safety
incidents. Key parts of our approach were a census of
267 NHS acute, ambulance and mental health trusts in
Autumn 2004, followed by a re-survey in August 2005
and an omnibus survey of patients (Appendix 2). We also
reviewed practices in other industries (Appendix 3) and
international healthcare systems (Appendix 4), and the
National Patient Safety Agencyâs progress in developing its
National Reporting and Learning System (Appendix 5) and
other related activities (Appendix 6).
6 An organisation with a memory1
was an important
milestone in the NHSâs patient safety agenda and marked
the drive to improve reporting and learning. At the
local level the vast majority of trusts have developed a
predominantly open and fair reporting culture but with
pockets of blame and scope to improve their strategies for
sharing good practice. Indeed in our re-survey we found
that local performance had continued to improve with more
trusts reporting having an open and fair reporting culture,
more trusts with open reporting systems and improvements
in perceptions of the levels of under-reporting. At the
national level, progress on developing the national reporting
system for learning has been slower than set out in the
Departmentâs strategy of 2001
3
and there is a need to
improve evaluation and sharing of lessons and solutions by
all organisations with a stake in patient safety. There is also
no clear system for monitoring that lessons are learned at the
local level. Specifically:
a The safety culture within trusts is improving, driven
largely by the Departmentâs clinical governance
initiative
4
and the development of more effective risk
management systems in response to incentives under
initiatives such as the NHS Litigation Authorityâs
Clinical Negligence Scheme for Trusts (Appendix 7).
However, trusts are still predominantly reactive in
their response to patient safety issues and parts of
some organisations still operate a blame culture.
b All trusts have established effective reporting systems
at the local level, although under-reporting remains
a problem within some groups of staff, types of
incidents and near misses. The National Patient Safety
Agency did not develop and roll out the National
Reporting and Learning System by December 2002
as originally envisaged. All trusts were linked to the
system by 31 December 2004. By August 2005, at
least 35 trusts still had not submitted any data to the
National Reporting and Learning System.
c Most trusts pointed to specific improvements
derived from lessons learnt from their local incident
reporting systems, but these are still not widely
promulgated, either within or between trusts.
The National Patient Safety Agency has provided
only limited feedback to trusts of evidence-based
solutions or actions derived from the national
reporting system. It published its first feedback report
from the Patient Safety Observatory in July 2005
3-loop Massive Contributions to the DIS Operator Matrix Element
Contributions to heavy flavour transition matrix elements in the variable
flavour number scheme are considered at 3-loop order. In particular a
calculation of the diagrams with two equal masses that contribute to the
massive operator matrix element is performed. In the Mellin
space result one finds finite nested binomial sums. In -space these sums
correspond to iterated integrals over an alphabet containing also square-root
valued letters.Comment: 4 pages, Contribution to the Proceedings of QCD '14, Montpellier,
July 201
XXX. Discours
This is the author accepted manuscript. The final version is available from Springer Verlag via the DOI in this record.Mapping between non-preference- and preference-based health-related quality-of-life instruments has become a common technique for estimating health state utility values for use in economic evaluations. Despite the increased use of mapped health state utility estimates in health technology assessment and economic evaluation, the methods for deriving them have not been fully justified. Recent guidelines aim to standardise reporting of the methods used to map between instruments but do not address fundamental concerns in the underlying conceptual model. Current mapping methods ignore the important conceptual issues that arise when extrapolating results from potentially unrelated measures. At the crux of the mapping problem is a question of validity; because one instrument can be used to predict the scores on another, does this mean that the same preference for health is being measured in actual and estimated health state utility values? We refer to this as conceptual validity. This paper aims to (1) explain the idea of conceptual validity in mapping and its implications; (2) consider the consequences of poor conceptual validity when mapping for decision making in the context of healthcare resource allocation; and (3) offer some preliminary suggestions for improving conceptual validity in mapping
3-Loop Heavy Flavor Corrections in Deep-Inelastic Scattering with Two Heavy Quark Lines
We consider gluonic contributions to the heavy flavor Wilson coefficients at
3-loop order in QCD with two heavy quark lines in the asymptotic region . Here we report on the complete result in the case of two equal
masses for the massive operator matrix element ,
which contributes to the corresponding heavy flavor transition matrix element
in the variable flavor number scheme. Nested finite binomial sums and iterated
integrals over square-root valued alphabets emerge in the result for this
quantity in and -space, respectively. We also present results for the
case of two unequal masses for the flavor non-singlet OMEs and on the scalar
integrals ic case of , which were calculated without a further
approximation. The graphs can be expressed by finite nested binomial sums over
generalized harmonic sums, the alphabet of which contains rational letters in
the ratio .Comment: 10 pages LATEX, 1 Figure, Proceedings of Loops and Legs in Quantum
Field Theory, Weimar April 201
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