Modelling of the radiative properties of an opaque porous ceramic layer

Solid Oxide Fuel Cells (SOFCs) operate at temperatures above 1,100 K where radiation effects can be significant. Therefore, an accurate thermal model of an SOFC requires the inclusion of the contribution of thermal radiation. This implies that the thermal radiative properties of the oxide ceramics used in the design of SOFCs must be known. However, little information can be found in the literature concerning their operating temperatures. On the other hand, several types of ceramics with different chemical compositions and microstructures for designing efficient cells are now being tested. This is a situation where the use of a numerical tool making possible the prediction of the thermal radiative properties of SOFC materials, whatever their chemical composition and microstructure are, may be a decisive help. Using this method, first attempts to predict the radiative properties of a lanthanum nickelate porous layer deposited onto an yttria stabilized zirconium substrate can be reported

Similarity solutions for unsteady shear-stress-driven flow of Newtonian and power-law fluids : slender rivulets and dry patches

Unsteady flow of a thin film of a Newtonian fluid or a non-Newtonian power-law fluid with power-law index N driven by a constant shear stress applied at the free surface, on a plane inclined at an angle α to the horizontal, is considered. Unsteady similarity solutions representing flow of slender rivulets and flow around slender dry patches are obtained. Specifically, solutions are obtained for converging sessile rivulets (0 < α < π/2) and converging dry patches in a pendent film (π/2 < α < π), as well as for diverging pendent rivulets and diverging dry patches in a sessile film. These solutions predict that at any time t, the rivulet and dry patch widen or narrow according to |x|3/2, and the film thickens or thins according to |x|, where x denotes distance down the plane, and that at any station x, the rivulet and dry patch widen or narrow like |t|−1, and the film thickens or thins like |t|−1, independent of N

Criteria for return to running after anterior cruciate ligament reconstruction: a scoping review

Objective To describe the criteria used to guide clinical decision-making regarding when a patient is ready to return to running (RTR) after ACL reconstruction. Design Scoping review. Data sources The MEDLINE (PubMed), EMBASE, Web of Science, PEDro, SPORT Discus and Cochrane Library electronic databases. We also screened the reference lists of included studies and conducted forward citation tracking. Eligibility criteria for selecting studies Reported at least one criterion for permitting adult patients with primary ACL reconstruction to commence running postoperatively. Results 201 studies fulfilled the inclusion criteria and reported 205 time-based criteria for RTR. The median time from when RTR was permitted was 12 postoperative weeks (IQR=3.3, range 5-39 weeks). Fewer than one in five studies used additional clinical, strength or performance-based criteria for decision-making regarding RTR. Aside from time, the most frequently reported criteria for RTR were: full knee range of motion or amp;gt;95% of the non-injured knee plus no pain or pain amp;lt;2 on visual analogue scale; isometric extensor limb symmetry index (LSI)amp;gt; 70% plus extensor and flexor LSIamp;gt; 70%; and hop test LSIamp;gt; 70%. Conclusions Fewer than one in five studies reported clinical, strength or performance-based criteria for RTR even though best evidence recommends performance-based criteria combined with time-based criteria to commence running activities following ACL reconstruction.The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors

Confusion after spine injury: cerebral fat embolism after traumatic rupture of a Tarlov cyst: Case report

<p>Abstract</p> <p>Background</p> <p>Acute low back pain is a very common symptom and reason for many medical consultations. In some unusual circumstances it could be linked to a rare aetiology.</p> <p>Case presentation</p> <p>We report a 70-year-old man with an 8-month history of left posterior thigh and leg pain who had sudden confusion after a fall from standing. It was due to cerebral fat embolism suspected by computed tomography scan, later confirmed by brain magnetic resonance imaging (MRI). A spinal MRI scan was then performed and revealed a sacral fracture which drained into an unknown perineurial cyst (Tarlov cyst). Under medical observation the patient fully recovered within three weeks.</p> <p>Conclusions</p> <p>Sacral perineurial cysts are rare, however they remain a potential cause of lumbosacral radiculopathy.</p

A massive, quiescent galaxy at redshift of z=3.717

In the early Universe finding massive galaxies that have stopped forming stars present an observational challenge as their rest-frame ultraviolet emission is negligible and they can only be reliably identified by extremely deep near-infrared surveys. These have revealed the presence of massive, quiescent early-type galaxies appearing in the universe as early as z$\sim$2, an epoch 3 Gyr after the Big Bang. Their age and formation processes have now been explained by an improved generation of galaxy formation models where they form rapidly at z$\sim$3-4, consistent with the typical masses and ages derived from their observations. Deeper surveys have now reported evidence for populations of massive, quiescent galaxies at even higher redshifts and earlier times, however the evidence for their existence, and redshift, has relied entirely on coarsely sampled photometry. These early massive, quiescent galaxies are not predicted by the latest generation of theoretical models. Here, we report the spectroscopic confirmation of one of these galaxies at redshift z=3.717 with a stellar mass of 1.7$\times$10$^{11}$ M$_\odot$ whose absorption line spectrum shows no current star-formation and which has a derived age of nearly half the age of the Universe at this redshift. The observations demonstrates that the galaxy must have quickly formed the majority of its stars within the first billion years of cosmic history in an extreme and short starburst. This ancestral event is similar to those starting to be found by sub-mm wavelength surveys pointing to a possible connection between these two populations. Early formation of such massive systems is likely to require significant revisions to our picture of early galaxy assembly.Comment: 6 pages, 7 figures. This is the final preprint corresponding closely to the published version. Uploaded 6 months after publication in accordance with Nature polic

Universal Vectorial and Ultrasensitive Nanomechanical Force Field Sensor

Miniaturization of force probes into nanomechanical oscillators enables ultrasensitive investigations of forces on dimensions smaller than their characteristic length scale. Meanwhile it also unravels the force field vectorial character and how its topology impacts the measurement. Here we expose an ultrasensitive method to image 2D vectorial force fields by optomechanically following the bidimensional Brownian motion of a singly clamped nanowire. This novel approach relies on angular and spectral tomography of its quasi frequency-degenerated transverse mechanical polarizations: immersing the nanoresonator in a vectorial force field does not only shift its eigenfrequencies but also rotate eigenmodes orientation as a nano-compass. This universal method is employed to map a tunable electrostatic force field whose spatial gradients can even take precedence over the intrinsic nanowire properties. Enabling vectorial force fields imaging with demonstrated sensitivities of attonewton variations over the nanoprobe Brownian trajectory will have strong impact on scientific exploration at the nanoscale

Patient-physician interaction in general practice and health inequalities in a multidisciplinary study: design, methods and feasibility in the French INTERMEDE study

<p>Abstract</p> <p>Background</p> <p>The way in which patients and their doctors interact is a potentially important factor in optimal communication during consultations as well as treatment, compliance and follow-up care. The aim of this multidisciplinary study is to use both qualitative and quantitative methods to explore the 'black box' that is the interaction between the two parties during a general practice consultation, and to identify factors therein that may contribute to producing health inequalities. This paper outlines the original multidisciplinary methodology used, and the feasibility of this type of study.</p> <p>Methods and design</p> <p>The study design combines methodologies on two separate samples in two phases. Firstly, a qualitative phase collected ethnographical and sociological data during consultation, followed by in-depth interviews with both patients and doctors independently. Secondly, a quantitative phase on a different sample of patients and physicians collected data via several questionnaires given to patients and doctors consisting of specific 'mirrored' questions asked post-consultation, as well as collecting information on patient and physician characteristics.</p> <p>Discussion</p> <p>The design and methodology used in this study were both successfully implemented, and readily accepted by doctors and patients alike. This type of multidisciplinary study shows great potential in providing further knowledge into the role of patient/physician interaction and its influence on maintaining or producing health inequalities. The next challenge in this study will be implementing the multidisciplinary approach during the data analysis.</p

Synchronized Audio-Visual Transients Drive Efficient Visual Search for Motion-in-Depth

In natural audio-visual environments, a change in depth is usually correlated with a change in loudness. In the present study, we investigated whether correlating changes in disparity and loudness would provide a functional advantage in binding disparity and sound amplitude in a visual search paradigm. To test this hypothesis, we used a method similar to that used by van der Burg et al. to show that non-spatial transient (square-wave) modulations of loudness can drastically improve spatial visual search for a correlated luminance modulation. We used dynamic random-dot stereogram displays to produce pure disparity modulations. Target and distractors were small disparity-defined squares (either 6 or 10 in total). Each square moved back and forth in depth in front of the background plane at different phases. The target’s depth modulation was synchronized with an amplitude-modulated auditory tone. Visual and auditory modulations were always congruent (both sine-wave or square-wave). In a speeded search task, five observers were asked to identify the target as quickly as possible. Results show a significant improvement in visual search times in the square-wave condition compared to the sine condition, suggesting that transient auditory information can efficiently drive visual search in the disparity domain. In a second experiment, participants performed the same task in the absence of sound and showed a clear set-size effect in both modulation conditions. In a third experiment, we correlated the sound with a distractor instead of the target. This produced longer search times, indicating that the correlation is not easily ignored

Caterpillars and fungal pathogens: two co-occurring parasites of an ant-plant mutualism

In mutualisms, each interacting species obtains resources from its partner that it would obtain less efficiently if alone, and so derives a net fitness benefit. In exchange for shelter (domatia) and food, mutualistic plant-ants protect their host myrmecophytes from herbivores, encroaching vines and fungal pathogens. Although selective filters enable myrmecophytes to host those ant species most favorable to their fitness, some insects can by-pass these filters, exploiting the rewards supplied whilst providing nothing in return. This is the case in French Guiana for Cecropia obtusa (Cecropiaceae) as Pseudocabima guianalis caterpillars (Lepidoptera, Pyralidae) can colonize saplings before the installation of their mutualistic Azteca ants. The caterpillars shelter in the domatia and feed on food bodies (FBs) whose production increases as a result. They delay colonization by ants by weaving a silk shield above the youngest trichilium, where the FBs are produced, blocking access to them. This probable temporal priority effect also allows female moths to lay new eggs on trees that already shelter caterpillars, and so to occupy the niche longer and exploit Cecropia resources before colonization by ants. However, once incipient ant colonies are able to develop, they prevent further colonization by the caterpillars. Although no higher herbivory rates were noted, these caterpillars are ineffective in protecting their host trees from a pathogenic fungus, Fusarium moniliforme (Deuteromycetes), that develops on the trichilium in the absence of mutualistic ants. Therefore, the Cecropia treelets can be parasitized by two often overlooked species: the caterpillars that shelter in the domatia and feed on FBs, delaying colonization by mutualistic ants, and the fungal pathogen that develops on old trichilia. The cost of greater FB production plus the presence of the pathogenic fungus likely affect tree growth