416 research outputs found
q-deformed dynamics and Josephson junction
We define a generalized rate equation for an observable in quantum mechanics,
that involves a parameter q and whose limit gives the standard
Heisenberg equation. The generalized rate equation is used to study dynamics of
current biased Josephson junction. It is observed that this toy model
incorporates diffraction like effects in the critical current. Physical
interpretation for q is provided which is also shown to be q-deformation
parameter.Comment: LaTeX 9 pages, submitted Mod. Phys. Lett. B, e-mail: [email protected]
Geometry of escort distributions
Given an original distribution, its statistical and probabilistic attributs
may be scanned by the associated escort distribution introduced by Beck and
Schlogl and employed in the formulation of nonextensive statistical mechanics.
Here, the geometric structure of the one-parameter family of the escort
distributions is studied based on the Kullback-Leibler divergence and the
relevant Fisher metric. It is shown that the Fisher metric is given in terms of
the generalized bit-variance, which measures fluctuations of the crowding index
of a multifractal. The Cramer-Rao inequality leads to the fundamental limit for
precision of statistical estimate of the order of the escort distribution. It
is also quantitatively discussed how inappropriate it is to use the original
distribution instead of the escort distribution for calculating the expectation
values of physical quantities in nonextensive statistical mechanics.Comment: 12 pages, no figure
(How) does productivity matter in the foundational economy?
Academics and policy makers have increasingly recognised the importance of mundane economic activities – variously termed foundational or everyday – by academics and policy makers. The foundational or everyday economy is now featuring in local industrial strategy and economic action plans, because the desirable high-tech sectors on the ‘frontier’ cannot diffuse prosperity within and between regions. This paper aims to distinguish between several different approaches to the foundational or everyday economy and argues that a constructive approach needs to break with the preoccupation about improving productivity. This argument is developed in three stages. First, we distinguish between a social approach and a more technical economic approach to delimiting this other mundane economy; the defining feature of the foundational in the social approach is contribution to wellbeing and in the technical economic approach it is low productivity. The second section presents and explores productivity evidence on output per worker hour across a range of foundational activities and by region. Drawing out the implications of observed diversity and heterogeneity, the third section develops an argument about how productivity has limited relevance as measure and target in foundational activitie
Performance Evaluation of Multiple Differential Detection for Third Generation Mobile Communication System
Third generation mobile communication system is widely used nowadays. One of its parameter standard, which is QPSK modulation has been adopted by International Telecommunication Union (ITU) to be used in IMT-2000. However, due to amplitude variations introduced in QPSK, a rather robust and reliable data modulation technique, namely the p/4-shift Differential QPSK is proposed. For detection
purposes, two types of detectors are evaluated for their
performance in AWGN and Rayleigh fading channels.A differential detection technique called multiple differential detection technique which uses maximumlikelihood sequence estimation (MLSE) of the
transmitted phases is compared with conventional
differential detection which uses symbol-by-symbol
detection. By using some of the IMT-2000 standard
parameters, the simulation results show that multiple
differential detection scheme performs much better
than conventional differential detection scheme
National Vascular Registry: 2015 Annual Report.
The National Vascular Registry is commissioned by the Healthcare Quality Improvement
Partnership (HQIP) to measure the quality and outcomes of care for patients who undergo
major vascular surgery in NHS hospitals in England and Wales. It aims to provide
comparative information on the performance of NHS vascular units and thereby support
local quality improvement as well as inform patients about major vascular interventions
delivered in the NHS. As such, all NHS hospitals in England, Wales, Scotland and Northern
Ireland are encouraged to participate in the Registry.
The measures used to describe the patterns and outcomes of care are drawn from various
national guidelines including: the “Provision of Services for Patients with Vascular Disease”
document and the Quality Improvement Frameworks published by the Vascular Society, and
the National Institute for Health and Care Excellence (NICE) guidelines on stroke and
peripheral arterial disease.
This report provides a description of the care provided by NHS vascular units, and contains
information on the process and outcomes of care for: (i) patients undergoing abdominal
aortic aneurysm (AAA) repair, (ii) patients undergoing carotid endarterectomy, (iii) patients
undergoing a revascularisation procedure (angioplasty/stent or bypass) or major
amputation for lower-limb peripheral arterial disease (PAD). In addition, the report
presents the findings of an organisational audit conducted in August 2015
National Vascular Registry: 2014 Progress Report.
The National Vascular Registry is commissioned by the Healthcare Quality Improvement
Partnership (HQIP) to measure the quality and outcomes of care for patients who undergo
major vascular surgery in NHS hospitals in England and Wales. It aims to provide
comparative information on the performance of NHS hospitals and thereby support local
quality improvement as well as inform patients about the care delivered in the NHS. As
such, all NHS hospitals in England, Wales, Scotland and Northern Ireland are encouraged to
participate in the Registry.
The measures used to describe the patterns and outcomes of care are drawn from various
national guidelines including: the “2014 The Provision of Services for Patients with Vascular
Disease” and the Quality Improvement Frameworks published by the Vascular Society, and
the National Institute for Health and Care Excellence (NICE) guidelines on stroke and
peripheral arterial disease.
In 2014, the Registry published NHS trust and surgeon-level information for elective infrarenal
Abdominal Aortic Aneurysm (AAA) repair and carotid endarterectomy on the Registry
website. From 28 October, information on both procedures has been available on the
www.vsqip.org.uk website for all UK NHS trusts that currently perform them. For English
NHS trusts, the same information was published for individual consultants, as part of NHS
England’s “Everyone Counts: Planning for Patients 2013/4” initiative. Consultant-level
information was also published for NHS hospitals in Wales, Scotland and Northern Ireland
for consenting surgeons.
This progress report aims to complement that information by (1) providing an overview of
care delivered by the NHS at a national level, and (2) describing various developments
within the National Vascular Registry. The Registry will publish its next annual report on
major vascular surgery in November 2015
Design Simulation of Multiple Differential Transceiver at 2.0 GHz for Third Generation Mobile Communication System
Third generation mobile communication system is widely used nowadays. One of its parameter standard, which is QPSK modulation has been adopted by International Telecommunication Union (ITU) to be used in IMT-2000. However, due to amplitude variations introduced in QPSK, a rather robust and reliable data modulation technique, namely the 7c/4-shift Differential QPSK is proposed. For detection purposes, two types of detectors are evaluated for their performance in AWGN and Rayleigh fading channels. A differential detection technique called multiple differential detection technique which uses maximum-likelihood sequence estimation (MLSE) of the transmitted phases is compared with conventional differential detection which uses symbol-bysymbol detection. By using some of the IMT-2000 standard parameters, the simulation results show that multiple differential detection scheme performs much
better than conventional differential detection scheme
Editor's Choice - Delays to Surgery and Procedural Risks Following Carotid Endarterectomy in the UK National Vascular Registry.
OBJECTIVE: Guidelines recommend that patients suffering an ischaemic transient ischaemic attack (TIA) or stroke caused by carotid artery stenosis should undergo carotid endarterectomy (CEA) within 14 days. METHOD: The degree to which UK vascular units met this standard was examined and whether rapid interventions were associated with procedural risks. The study analysed patients undergoing CEA between January 2009 and December 2014 from 100 UK NHS hospitals. Data were collected on patient characteristics, intervals of time from symptoms to surgery, and 30-day postoperative outcomes. The relationship between outcomes and time from symptom to surgery was evaluated using multilevel multivariable logistic regression. RESULTS: In 23,235 patients, the median time from TIA/stroke to CEA decreased over time, from 22 days (IQR 10-56) in 2009 to 12 days (IQR 7-26) in 2014. The proportion of patients treated within 14 days increased from 37% to 58%. This improvement was produced by shorter times across the care pathway: symptoms to referral, from medical review to being seen by a vascular surgeon, and then to surgery. The spread of the median time from symptom to surgery among NHS hospitals shrank between 2009 and 2013 but then grew slightly. Low-, medium-, and high-volume NHS hospitals all improved their performance similarly. Performing CEA within 48 h of symptom onset was associated with a small increase in the 30-day stroke and death rate: 3.1% (0-2 days) compared with 2.0% (3-7 days); adjusted odds ratio 1.64 (95% CI 1.04-2.59) but not with longer delays. CONCLUSIONS: The delay from symptom to CEA in symptomatic patients with ipsilateral 50-99% carotid stenoses has reduced substantially, although 42% of patients underwent CEA after the recommended 14 days. The risk of stroke after CEA was low, but there may be a small increase in risk during the first 48 h after symptoms
Barnett-Pegg formalism of angle operators, revivals, and flux lines
We use the Barnett-Pegg formalism of angle operators to study a rotating
particle with and without a flux line. Requiring a finite dimensional version
of the Wigner function to be well defined we find a natural time quantization
that leads to classical maps from which the arithmetical basis of quantum
revivals is seen. The flux line, that fundamentally alters the quantum
statistics, forces this time quantum to be increased by a factor of a winding
number and determines the homotopy class of the path. The value of the flux is
restricted to the rational numbers, a feature that persists in the infinite
dimensional limit.Comment: 5 pages, 0 figures, Revte
Work extremum principle: Structure and function of quantum heat engines
We consider a class of quantum heat engines consisting of two subsystems
interacting via a unitary transformation and coupled to two separate baths at
different temperatures . The purpose of the engine is to extract
work due to the temperature difference. Its dynamics is not restricted to the
near equilibrium regime. The engine structure is determined by maximizing the
extracted work under various constraints. When this maximization is carried out
at finite power, the engine dynamics is described by well-defined temperatures
and satisfies the local version of the second law. In addition, its efficiency
is bounded from below by the Curzon-Ahlborn value and from
above by the Carnot value . The latter is reached|at finite
power|for a macroscopic engine, while the former is achieved in the equilibrium
limit . When the work is maximized at a zero power, even a small
(few-level) engine extracts work right at the Carnot efficiency.Comment: 16 pages, 5 figure
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