1,121 research outputs found
Ballistic magnon heat conduction and possible Poiseuille flow in the helimagnetic insulator CuOSeO
We report on the observation of magnon thermal conductivity 70
W/mK near 5 K in the helimagnetic insulator CuOSeO, exceeding that
measured in any other ferromagnet by almost two orders of magnitude. Ballistic,
boundary-limited transport for both magnons and phonons is established below 1
K, and Poiseuille flow of magnons is proposed to explain a magnon mean-free
path substantially exceeding the specimen width for the least defective
specimens in the range 2 K 10 K. These observations establish
CuOSeO as a model system for studying long-wavelength magnon dynamics.Comment: 10pp, 9 figures, accepted PRB (Editor's Suggestion
Chimeric influenza virus hemagglutinin containing either the NH2 terminus or the COOH terminus of G protein of vesicular stomatitis virus is defective in transport to the cell surface.
The effect of variation in interpretation of the La Trobe radiographic foot atlas on the prevalence of foot osteoarthritis in older women: the Chingford general population cohort.
Background: The prevalence of foot osteoarthritis (OA) is much less understood than hip, knee and hand OA. The foot is anatomically complex and different researchers have investigated different joints with lack of methodological standardisation across studies. The La Trobe Foot Atlas (LFA) is the first to address these issues in providing quantitative assessment of radiographic foot OA, but has not been tested externally. The aim of this study was to evaluate three different interpretive approaches to using the LFA for grading OA when scoring is difficult due to indistinct views of interosseous space and joint contour. Methods: Foot radiographs of all remaining participants (n = 218) assessed in the Chingford Women Study 23 year visit (mean (SD) for age: 75.5 years (5.1)) were scored using the LFA defined protocol (Technique 1). Two revised scoring strategies were applied to the radiographs in addition to the standard LFA analyses. Technique 2 categorised joints that were difficult to grade as 'missing'. Technique 3 included joints that were difficult to grade as an over estimated score. Radiographic OA prevalence was defined for the foot both collectively and separately for individual joints. Results: When radiographs were scored using the LFA (Technique 1), radiographic foot OA was present in 89.9%. For Technique 2 the presence of radiographic foot OA was 83.5% and for Technique 3 it was 97.2%. At the individual joint level, using Technique 1, the presence of radiographic foot OA was higher with a wider range (18.3-74.3%) than Technique 2 (17.9-46.3%) and lower with a wider range (18.3-74.3%) than Technique 3 (39.9-79.4%). Conclusion: The three different ways of interpreting the LFA scoring system when grading of individual joints is technically difficult and result in very different estimates of foot OA prevalence at both the individual joint and global foot level. Agreement on the best strategy is required to improve comparability between studies
Magnetism and structure of LixCoO2 and comparison to NaxCoO2
The magnetic properties and structure of LixCoO2 for x between 0.5 and 1.0
are reported. Co4+ is found to be high-spin in LixCoO2 for x between 0.94 and
1.0 and low-spin for x between 0.50 and 0.78. Weak antiferromagnetic coupling
is observed, increasing in strength as more Co4+ is introduced. At an x value
of about 0.65, the temperature-independent contribution to the magnetic
susceptibility and the electronic contribution to the specific heat are
largest. Neutron diffraction analysis reveals that the lithium oxide layer
expands perpendicular to the basal plane and the Li ions displace from their
ideal octahedral sites with decreasing x. A comparison of the structures of the
NaxCoO2 and LixCoO2 systems reveals that the CoO2 layer changes substantially
with alkali content in the former but is relatively rigid in the latter.
Further, the CoO6 octahedra in LixCoO2 are less distorted than those in
NaxCoO2. We postulate that these structural differences strongly influence the
physical properties in the two systems
Factors associated with alcohol reduction in harmful and hazardous drinkers following alcohol brief intervention in Scotland: a qualitative enquiry
Background: Alcohol Brief Intervention (ABI) uses a motivational counselling approach to support individuals to
reduce excessive alcohol consumption. There is growing evidence on ABI’s use within various health care settings,
although how they work and which components enhance success is largely unknown. This paper reports on the
qualitative part of a mixed methods study. It explores enablers and barriers associated with alcohol reduction
following an ABI. It focuses on alcohol’s place within participants’ lives and their personal perspectives on reducing
consumption. There are a number of randomised controlled trials in this field though few ABI studies have
addressed the experiences of hazardous/harmful drinkers. This study examines factors associated with alcohol
reduction in harmful/hazardous drinkers following ABI.
Methods: This qualitative study was underpinned by a realist evaluation approach and involved semistructured
interviews with ten harmful or hazardous alcohol drinkers. Participants (n = 10) were from the
intervention arm of a randomised controlled trial (n = 124). All had received ABI, a 20 min motivational
counselling interview, six months previously, and had reduced their alcohol consumption. Interviews were
recorded, transcribed verbatim and thematically analysed.
Results: Participants described their views on alcohol, its’ place in their lives, their personal perspectives on
reducing their consumption and future aspirations.
Conclusions: The findings provide an insight into participants’ views on alcohol, ABI, and the barriers and enablers
to change. Participants described a cost benefit analysis, with some conscious consideration of the advantages and
disadvantages of reducing intake or abstaining from alcohol. Findings suggest that, whilst hospital admission can act
as a catalyst, encouraging individuals to reflect on their alcohol consumption through ABI may consolidate this, turning
this reflective moment into action. Sustainability may be enhanced by the presence of a ‘significant other’ who
encourages and experiences benefit. In addition having a purpose or structure with activities linked to employment
and/or social and leisure pursuits offers the potential to enhance and sustain reduced alcohol consumption.
Trial registration: Trial registration number TRN NCT00982306 September 22nd 200
Pressure-Induced Effects on the Structure of the FeSe Superconductor
A polycrystalline sample of FeSe, which adopts the tetragonal PbO-type
structure (P4/nmm) at room temperature, has been prepared using solid state
reaction. We have investigated pressure-induced structural changes in
tetragonal FeSe at varying hydrostatic pressures up to 0.6 GPa in the
orthorhombic (T = 50 K) and tetragonal (T = 190 K) phases using high resolution
neutron powder diffraction. We report that the structure is quite compressible
with a Bulk modulus around 31 GPa to 33 GPa and that the pressure response is
anisotropic with a larger compressibility along the c-axis. Key bond angles of
the SeFe4 pyramids and FeSe4 tetrahedra are also determined as a function of
pressure
Discovery, activity and characterisation of an AA10 lytic polysaccharide oxygenase from the shipworm symbiont Teredinibacter turnerae
Background: The quest for novel enzymes for cellulosic biomass-degradation has recently been focussed on lytic polysaccharide monooxygenases (LPMOs/PMOs), Cu-containing proteins that catalyse the oxidative degradation of otherwise recalcitrant polysaccharides using O2 or H2O2 as a co-substrate. Results: Although classical saprotrophic fungi and bacteria have been a rich source of lytic polysaccharide monooxy genases (LPMOs), we were interested to see if LPMOs from less evident bio-environments could be discovered and assessed for their cellulolytic activity in a biofuel context. In this regard, the marine shipworm Lyrodus pedicellatus represents an interesting source of new enzymes, since it must digest wood particles ingested during its natural tunnel boring behaviour and plays host to a symbiotic bacterium, Teredinibacter turnerae, the genome of which has revealed a multitude of enzymes dedicated to biomass deconstruction. Here, we show that T. turnerae encodes a cellulose-active AA10 LPMO. The 3D structure, at 1.4 Å resolution, along with its EPR spectrum is distinct from other AA10 polysaccharide monooxygenases insofar as it displays a “histidine-brace” catalytic apparatus with changes to the surrounding coordination sphere of the copper. Furthermore, TtAA10A possesses a second, surface accessible, Cu site 14 Å from the classical catalytic centre. Activity measurements show that the LPMO oxidises cellulose and thereby signifcantly augments the rate of degradation of cellulosic biomass by classical glycoside hydrolases. Conclusion: Shipworms are wood-boring marine molluscs that can live on a diet of lignocellulose. Bacterial sym bionts of shipworms provide many of the enzymes needed for wood digestion. The shipworm symbiont T. turnerae produces one of the few LPMOs yet described from the marine environment, notably adding to the capability of shipworms to digest recalcitrant polysaccharides
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Spring School on Language, Music, and Cognition: Organizing Events in Time
The interdisciplinary spring school “Language, music, and cognition: Organizing events in time” was held from February 26 to March 2, 2018 at the Institute of Musicology of the University of Cologne. Language, speech, and music as events in time were explored from different perspectives including evolutionary biology, social cognition, developmental psychology, cognitive neuroscience of speech, language, and communication, as well as computational and biological approaches to language and music. There were 10 lectures, 4 workshops, and 1 student poster session.
Overall, the spring school investigated language and music as neurocognitive systems and focused on a mechanistic approach exploring the neural substrates underlying musical, linguistic, social, and emotional processes and behaviors. In particular, researchers approached questions concerning cognitive processes, computational procedures, and neural mechanisms underlying the temporal organization of language and music, mainly from two perspectives: one was concerned with syntax or structural representations of language and music as neurocognitive systems (i.e., an intrapersonal perspective), while the other emphasized social interaction and emotions in their communicative function (i.e., an interpersonal perspective). The spring school not only acted as a platform for knowledge transfer and exchange but also generated a number of important research questions as challenges for future investigations
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