5,334 research outputs found
Study of the volume and spin collapse in orthoferrite LuFeO_3 using LDA+U
Rare earth (R) orthoferrites RFeO_3 exhibit large volume transitions
associated with a spin collapse. We present here ab initio calculations on
LuFeO_3. We show that taking into account the strong correlation among the
Fe-3d electrons is necessary. Indeed, with the LDA+U method in the Projector
Augmented Wave (PAW), we are able to describe the isostructural phase
transition at 50 GPa, as well as a volume discontinuity of 6.0% at the
transition and the considerable reduction of the magnetic moment on the Fe
ions. We further investigate the effect of the variation of U and J and find a
linear dependence of the transition pressure on these parameters. We give an
interpretation for the non-intuitive effect of J. This emphasizes the need for
a correct determination of these parameters especially when the LDA+U is
applied to systems (e.g in geophysical investigations) where the transition
pressure is a priori unknown
Bluebelle pilot randomised controlled trial of three wound dressing strategies to reduce surgical site infection in primary surgical wounds
Objective Surgical site infection (SSI) affects up to 25% of primary surgical wounds. Dressing strategies may influence SSI risk. The Bluebelle study assessed the feasibility of a multicentre randomised controlled trial (RCT) to evaluate the effectiveness and cost-effectiveness of different dressing strategies to reduce SSI in primary surgical wounds.
Design A pilot, factorial RCT.
Setting Five UK hospitals.
Participants Adults undergoing abdominal surgery with a primary surgical wound.
Interventions Participants were randomised to ‘simple dressing’, ‘glue-as-a-dressing’ or ‘no dressing’, and to the time at which the treatment allocation was disclosed to the surgeon (disclosure time, before or after wound closure).
Primary and secondary outcome measures Feasibility outcomes focused on recruitment, adherence to randomised allocations, reference assessment of SSI and response rates to participant-completed and observer-completed questionnaires to assess SSI (proposed primary outcome for main trial), wound experience and symptoms, and quality of life (EQ-5D-5L).
Results Between March and November 2016, 1115 patients were screened; 699 (73.4%) were eligible and approached, 415 (59.4%) consented and 394 (35.3%) were randomised (simple dressing=133, glue=129 and ‘no dressing’=132). Non-adherence to dressing allocation was 2% (3/133), 6% (8/129) and 15% (20/132), respectively. Adherence to disclosure time was 99% and 86% before and after wound closure, respectively. The overall rate of SSI (reference assessment) was 18.1% (51/281). Response rates to the Wound Healing Questionnaire and other questionnaires ranged from >90% at 4 days to 68% at 4–8 weeks.
Conclusions A definitive RCT of dressing strategies including ‘no dressing’ is feasible. Further work is needed to optimise questionnaire response rates
Raman and nuclear magnetic resonance investigation of alkali metal vapor interaction with alkene-based anti-relaxation coating
The use of anti-relaxation coatings in alkali vapor cells yields substantial
performance improvements by reducing the probability of spin relaxation in wall
collisions by several orders of magnitude. Some of the most effective
anti-relaxation coating materials are alpha-olefins, which (as in the case of
more traditional paraffin coatings) must undergo a curing period after cell
manufacturing in order to achieve the desired behavior. Until now, however, it
has been unclear what physicochemical processes occur during cell curing, and
how they may affect relevant cell properties. We present the results of
nondestructive Raman-spectroscopy and magnetic-resonance investigations of the
influence of alkali metal vapor (Cs or K) on an alpha-olefin, 1-nonadecene
coating the inner surface of a glass cell. It was found that during the curing
process, the alkali metal catalyzes migration of the carbon-carbon double bond,
yielding a mixture of cis- and trans-2-nonadecene.Comment: 5 pages, 6 figure
Density Functional Study of Cubic to Rhombohedral Transition in -AlF
Under heating, -AlF undergoes a structural phase transition from
rhombohedral to cubic at temperature around 730 K. The density functional
method is used to examine the =0 energy surface in the structural parameter
space, and finds the minimum in good agreement with the observed rhombohedral
structure. The energy surface and electronic wave-functions at the minimum are
then used to calculate properties including density of states, -point
phonon modes, and the dielectric function. The dipole formed at each fluorine
ion in the low temperature phase is also calculated, and is used in a classical
electrostatic picture to examine possible antiferroelectric aspects of this
phase transition.Comment: A 6-page manuscript with 4 figures and 4 table
Development and testing of a database of NIH research funding of AAPM members: A report from the AAPM Working Group for the Development of a Research Database (WGDRD).
PURPOSE: To produce and maintain a database of National Institutes of Health (NIH) funding of the American Association of Physicists in Medicine (AAPM) members, to perform a top-level analysis of these data, and to make these data (hereafter referred to as the AAPM research database) available for the use of the AAPM and its members. METHODS: NIH-funded research dating back to 1985 is available for public download through the NIH exporter website, and AAPM membership information dating back to 2002 was supplied by the AAPM. To link these two sources of data, a data mining algorithm was developed in Matlab. The false-positive rate was manually estimated based on a random sample of 100 records, and the false-negative rate was assessed by comparing against 99 member-supplied PI_ID numbers. The AAPM research database was queried to produce an analysis of trends and demographics in research funding dating from 2002 to 2015. RESULTS: A total of 566 PI_ID numbers were matched to AAPM members. False-positive and -negative rates were respectively 4% (95% CI: 1-10%, N = 100) and 10% (95% CI: 5-18%, N = 99). Based on analysis of the AAPM research database, in 2015 the NIH awarded 116M, which is lower than the historic mean of $120M (in 2015 USD). CONCLUSIONS: A database of NIH-funded research awarded to AAPM members has been developed and tested using a data mining approach, and a top-level analysis of funding trends has been performed. Current funding of AAPM members is lower than the historic mean. The database will be maintained by members of the Working group for the development of a research database (WGDRD) on an annual basis, and is available to the AAPM, its committees, working groups, and members for download through the AAPM electronic content website. A wide range of questions regarding financial and demographic funding trends can be addressed by these data. This report has been approved for publication by the AAPM Science Council
High sensitivity cardiac troponin T and N-terminal pro-BNP predict cardiovascular events and death in patients with type 2 diabetes mellitus
n/
Prospects for terahertz imaging the human skin cancer with the help of gold-nanoparticles-based terahertz-to-infrared converter
The design is suggested, and possible operation parameters are discussed, of
an instrument to inspect a skin cancer tumour in the terahertz (THz) range,
transferring the image into the infrared (IR) and making it visible with the
help of standard IR camera. The central element of the device is the THz-to-IR
converter, a Teflon or silicon film matrix with embedded 8.5 nm diameter gold
nanoparticles. The use of external THz source for irradiating the biological
tissue sample is presumed. The converter's temporal characteristics enable its
performance in a real-time scale. The details of design suited for the
operation in transmission mode (in vitro) or on the human skin in reflection
mode {in vivo) are specified.Comment: To be published in the proceedings of the FANEM2018 workshop - Minsk,
3-5 June 201
Transient Gamma Ray Spectrometer Measurements of Gamma-Ray Lines from Novae. I. Limits on the Positron Annihilation Line in Five Individual Novae
The Transient Gamma Ray Spectrometer (TGRS) on board the WIND spacecraft has
spent most of the interval 1995-1997 in a high-altitude orbit where gamma-ray
backgrounds are low. Its high-resolution Ge spectrometer is thus able to detect
weak lines which are slightly offset from stronger background features. One
such line is predicted from nucleosynthesis in classical novae, where
beta-decays on a time-scale of a few hours in an expanding envelope produce
positrons that annihilate to generate a line which is blueshifted by a few keV
away from the background annihilation line at 511 keV. The broad TGRS field of
view contained five known Galactic novae during 1995 January - 1997 June, and
we have searched the spectra taken around the times of these events for the
blueshifted nova annihilation line. Although no definite detections were made,
the method is shown to be sensitive enough to detect novae occurring on
ONeMg-rich white dwarfs out to about 2.5 kpc.Comment: 27 pp. + 10 figs., or offprint mailed by request to
[email protected]
Understanding settlement services literacy and the provision of settlement services for humanitarian migrants in Australia : a service provider perspective
Over the past 40 years, successive Australian Governments have developed a comprehensive programme of settlement services (SS) designed to improve settlement outcomes for humanitarian migrants. Many humanitarian migrants do not arrive with the appropriate skills and abilities to fully benefit from available SS. “Settlement services literacy” (SSL) has been proposed as a framework to contextualise factors that may enable or constrain humanitarian migrants' utilisation of SS. The aim of this study was to investigate the provision of SS in relation to SSL, that is humanitarian migrants' ability to effectively
access information and services, to critically assess services, and to politically mobilise and effect change. Qualitative interviews were conducted with 26 service providers representing 19 organisations in Greater Western Sydney (n = 8) and Melbourne (n = 11). The study found that SS programmes address many of the indicators that promote SSL acquisition. However, this is not achieved systematically, nor do the programmes reflect all indicators across the three SSL levels. This study provides new insights into various factors impacting the effectiveness of SS provision and SSL acquisition. These insights can inform future programme policy reforms and contribute to more effective and responsive service systems that meet the diverse and complex needs of humanitarian migrants
- …