2,417 research outputs found
When images work faster than words: The integration of content-based image retrieval with the Northumbria Watermark Archive
Information on the manufacture, history, provenance, identification, care and conservation of paper-based artwork/objects is disparate and not always readily available. The Northumbria Watermark Archive will incorporate such material into a database, which will be made freely available on the Internet providing an invaluable resource for conservation, research and education. The efficiency of a database is highly dependant on its search mechanism. Text based mechanisms are frequently ineffective when a range of descriptive terminologies might be used i.e. when describing images or translating from foreign languages. In such cases a Content Based Image Retrieval (CBIR) system can be more effective. Watermarks provide paper with unique visual identification characteristics and have been used to provide a point of entry to the archive that is more efficient and effective than a text based search mechanism. The research carried out has the potential to be applied to any numerically large collection of images with distinctive features of colour, shape or texture i.e. coins, architectural features, picture frame profiles, hallmarks, Japanese artists stamps etc. Although the establishment of an electronic archive incorporating a CBIR system can undoubtedly improve access to large collections of images and related data, the development is rarely trouble free. This paper discusses some of the issues that must be considered i.e. collaboration between disciplines; project management; copying and digitising objects; content based image retrieval; the Northumbria Watermark Archive; the use of standardised terminology within a database as well as copyright issues
Projected free energies for polydisperse phase equilibria
A `polydisperse' system has an infinite number of conserved densities. We
give a rational procedure for projecting its infinite-dimensional free energy
surface onto a subspace comprising a finite number of linear combinations of
densities (`moments'), in which the phase behavior is then found as usual. If
the excess free energy of the system depends only on the moments used, exact
cloud, shadow and spinodal curves result; two- and multi-phase regions are
approximate, but refinable indefinitely by adding extra moments. The approach
is computationally robust and gives new geometrical insights into the
thermodynamics of polydispersity.Comment: 4 pages, REVTeX, uses multicol.sty and epsf.sty, 1 postscript figure
include
Patient satisfaction after conversion from warfarin to direct oral anticoagulants for patients on extended duration of anticoagulation for venous thromboembolism – The SWAN Study
Background
Warfarin is an anticoagulant medication proven effective in the initial treatment and secondary prevention of venous thromboembolism. Anti-Xa direct oral anticoagulants are alternatives to warfarin; however there is limited data assessing satisfaction after switching from warfarin to an anti-Xa direct oral anticoagulant in patients for treatment of venous thromboembolism.
Objectives
To assess medication satisfaction in patients requiring anticoagulation for venous thromboembolism after conversion from warfarin to an anti-Xa direct oral anticoagulant.
Methods
A retrospective cohort study with prospective assessment of satisfaction and review of adverse events following anti-Xa direct oral anticoagulant replacement of warfarin for treatment of venous thromboembolism. Out of 165 patients who had switched from warfarin to rivaroxaban or apixaban from an outpatient haematology practice, 126 patients consented for a survey of patient’s relative satisfaction of anti-Xa direct oral anticoagulant therapy compared with previous warfarin therapy using the Anti-Clot Burden and Benefits Treatment Scale and SWAN Score.
Results
The mean Anti-Clot Burden and Benefits and SWAN Score was 93% (56/60) and 83% (24.8/30) respectively reflecting high satisfaction with anti-Xa direct oral anticoagulants. 120 patients stated preference for anti-Xa direct oral anticoagulants over warfarin. Leading perceptions driving this was the reduction in frequency of medical contact and fewer bleeding side effects. Thirteen patients (10.3%) experienced an adverse event after the anti-Xa direct oral anticoagulant switch (majority were non-major bleeding) but most remained on anti-Xa direct oral anticoagulant treatment after management options were implemented with continued high satisfaction scores.
Conclusions
Patient satisfaction with anti-Xa direct oral anticoagulant therapy for the treatment and prevention of venous thromboembolism after switching from warfarin in routine clinical practice appeared high. Improved patient convenience including reduced frequency of medical contact and fewer unpredictable side effects were perceived as significant advantages of anti-Xa direct oral anticoagulants compared to warfarin
Cross-sectional scanning tunneling microscopy of InAs/GaAs(001) submonolayer quantum dots
Cross-sectional scanning tunneling microscopy (X-STM) was employed to
characterize the InAs submonolayer quantum dots (SMLQDs) grown on top of a
Si-doped GaAs(001) substrate in the presence of (2X4) and c(4X4) surface
reconstructions. Multiple layers were grown under different conditions to study
their effects on the formation, morphology and local composition of the SMLQDs.
The morphological and compositional variations in SMLQDs were observed by both
filled and emptystate imaging. A detailed analysis of indium segregation in the
SMLQDs layers was described by fitting local indium concentration profile with
a standard segregation model. A strong influence of arsenic flux over the
formation of the SMLQDs and indium incorporation was observed and reported. We
investigated the well-width fluctuations of the InGaAs quantum well (QW) in
which SMLQDs were formed . The monolayer fluctuations of the well width were
negligible compared to the more pronounced compositional fluctuations in all
the layers. Keywords: Submonolayer quantum dots, Surface reconstruction, X-STM,
Indium segregatio
Nuclear structure of 30S and its implications for nucleosynthesis in classical novae
The uncertainty in the 29P(p,gamma)30S reaction rate over the temperature
range of 0.1 - 1.3 GK was previously determined to span ~4 orders of magnitude
due to the uncertain location of two previously unobserved 3+ and 2+ resonances
in the 4.7 - 4.8 MeV excitation region in 30S. Therefore, the abundances of
silicon isotopes synthesized in novae, which are relevant for the
identification of presolar grains of putative nova origin, were uncertain by a
factor of 3. To investigate the level structure of 30S above the proton
threshold (4394.9(7) keV), a charged-particle spectroscopy and an in-beam
gamma-ray spectroscopy experiments were performed. Differential cross sections
of the 32S(p,t)30S reaction were measured at 34.5 MeV. Distorted wave Born
approximation calculations were performed to constrain the spin-parity
assignments of the observed levels. An energy level scheme was deduced from
gamma-gamma coincidence measurements using the 28Si(3He,n-gamma)30S reaction.
Spin-parity assignments based on measurements of gamma-ray angular
distributions and gamma-gamma directional correlation from oriented nuclei were
made for most of the observed levels of 30S. As a result, the resonance
energies corresponding to the excited states in 4.5 MeV - 6 MeV region,
including the two astrophysically important states predicted previously, are
measured with significantly better precision than before. The uncertainty in
the rate of the 29P(p,gamma)30S reaction is substantially reduced over the
temperature range of interest. Finally, the influence of this rate on the
abundance ratios of silicon isotopes synthesized in novae are obtained via 1D
hydrodynamic nova simulations.Comment: 22 pages, 12 figure
Existence of Spinorial States in Pure Loop Quantum Gravity
We demonstrate the existence of spinorial states in a theory of canonical
quantum gravity without matter. This should be regarded as evidence towards the
conjecture that bound states with particle properties appear in association
with spatial regions of non-trivial topology. In asymptotically trivial general
relativity the momentum constraint generates only a subgroup of the spatial
diffeomorphisms. The remaining diffeomorphisms give rise to the mapping class
group, which acts as a symmetry group on the phase space. This action induces a
unitary representation on the loop state space of the Ashtekar formalism.
Certain elements of the diffeomorphism group can be regarded as asymptotic
rotations of space relative to its surroundings. We construct states that
transform non-trivially under a -rotation: gravitational quantum states
with fractional spin.Comment: 26 pages, 6 figures. Changes made to section 2 and Lemma
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