3,755 research outputs found
Weak formulation for singular diffusion equation with dynamic boundary condition
In this paper, we propose a weak formulation of the singular diffusion
equation subject to the dynamic boundary condition. The weak formulation is
based on a reformulation method by an evolution equation including the
subdifferential of a governing convex energy. Under suitable assumptions, the
principal results of this study are stated in forms of Main Theorems A and B,
which are respectively to verify: the adequacy of the weak formulation; the
common property between the weak solutions and those in regular problems of
standard PDEs.Comment: 23 page
Electronic in-plane symmetry breaking at field-tuned quantum criticality in CeRhIn5
Electronic nematics are exotic states of matter where electronic interactions
break a rotational symmetry of the underlying lattice, in analogy to the
directional alignment without translational order in nematic liquid crystals.
Intriguingly such phases appear in the copper- and iron-based superconductors,
and their role in establishing high-temperature superconductivity remains an
open question. Nematicity may take an active part, cooperating or competing
with superconductivity, or may appear accidentally in such systems. Here we
present experimental evidence for a phase of nematic character in the heavy
fermion superconductor CeRhIn5. We observe a field-induced breaking of the
electronic tetragonal symmetry of in the vicinity of an antiferromagnetic (AFM)
quantum phase transition at Hc~50T. This phase appears in out-of-plane fields
of H*~28T and is characterized by substantial in-plane resistivity anisotropy.
The anisotropy can be aligned by a small in-plane field component, with no
apparent connection to the underlying crystal structure. Furthermore no
anomalies are observed in the magnetic torque, suggesting the absence of
metamagnetic transitions in this field range. These observations are indicative
of an electronic nematic character of the high field state in CeRhIn5. The
appearance of nematic behavior in a phenotypical heavy fermion superconductor
highlights the interrelation of nematicity and unconventional
superconductivity, suggesting nematicity to be a commonality in such materials
The Incidence of Arterial Stent Fractures with Exclusion of Coronary, Aortic, and Non-arterial Settings
Background: This study aimed to review the literature regarding fracture of arterial stents, especially its relation to location of placement, clinical relevance, and type of stents. Material and methods: We searched published articles in PubMed up to February 2008 by using the terms: stent fracture or stent breakage. Results: Thirty-one articles met our inclusion and exclusion criteria. Most of the studies reported fractures in stents placed in the superficial femoral artery or popliteal arteries. The cumulative incidence of stent fractures ranged from 2% to 65%, i.e. 0.6 to 60 per 1000 person-months. Stent fractures occur more frequently in the superficial femoral artery and are common when multiple stents are deployed and overlap. Stent fractures are associated with a higher risk of in-stent restenosis and re-occlusion. Conclusion: The incidence of stent fracture, its location of placement, and type of stent used were diverse across studies. Stent fracture may cause clinical deterioration especially in the femoropopliteal segment, and it should be detected before clinical manifestation appears. Further studies with larger study population involving new type of stents for a longer follow up period are warranted.Peer reviewe
{Rearrangement of the antiferromagnetic ordering at high magnetic fields in SmFeAsO and SmFeAsOF single crystals
The low-temperature antiferromagnetic state of the Sm-ions in both
nonsuperconducting SmFeAsO and superconducting SmFeAsOF single
crystals was studied by magnetic torque, magnetization, and magnetoresistance
measurements in magnetic fields up to 60~T and temperatures down to 0.6~K. We
uncover in both compounds a distinct rearrangement of the antiferromagnetically
ordered Sm-moments near ~T. This is seen in both, static and pulsed
magnetic fields, as a sharp change in the sign of the magnetic torque, which is
sensitive to the magnetic anisotropy and hence to the magnetic moment in the
-plane, ({\it i.e.} the FeAs-layers), and as a jump in the magnetization
for magnetic fields perpendicular to the conducting planes. This rearrangement
of magnetic ordering in ~T is essentially temperature independent and
points towards a canted or a partially polarized magnetic state in high
magnetic fields. However, the observed value for the saturation moment above
this rearrangement, suggests that the complete suppression of the
antiferromagnetism related to the Sm-moments would require fields in excess of
60~T. Such a large field value is particularly remarkable when compared to the
relatively small N\'{e}el temperature ~K, suggesting very
anisotropic magnetic exchange couplings. At the transition, magnetoresistivity
measurements show a crossover from positive to negative field-dependence,
indicating that the charge carriers in the FeAs planes are sensitive to the
magnetic configuration of the rare-earth elements. This is indicates a finite
magnetic/electronic coupling between the SmO and the FeAs layers which are
likely to mediate the exchange interactions leading to the long range
antiferromagnetic order of the Sm ions.Comment: 10 pages, 7 figures, accepted in Phys. Rev.
{SelfPose}: {3D} Egocentric Pose Estimation from a Headset Mounted Camera
We present a solution to egocentric 3D body pose estimation from monocular
images captured from downward looking fish-eye cameras installed on the rim of
a head mounted VR device. This unusual viewpoint leads to images with unique
visual appearance, with severe self-occlusions and perspective distortions that
result in drastic differences in resolution between lower and upper body. We
propose an encoder-decoder architecture with a novel multi-branch decoder
designed to account for the varying uncertainty in 2D predictions. The
quantitative evaluation, on synthetic and real-world datasets, shows that our
strategy leads to substantial improvements in accuracy over state of the art
egocentric approaches. To tackle the lack of labelled data we also introduced a
large photo-realistic synthetic dataset. xR-EgoPose offers high quality
renderings of people with diverse skintones, body shapes and clothing,
performing a range of actions. Our experiments show that the high variability
in our new synthetic training corpus leads to good generalization to real world
footage and to state of theart results on real world datasets with ground
truth. Moreover, an evaluation on the Human3.6M benchmark shows that the
performance of our method is on par with top performing approaches on the more
classic problem of 3D human pose from a third person viewpoint.Comment: 14 pages. arXiv admin note: substantial text overlap with
arXiv:1907.1004
Keep it SMPL: Automatic Estimation of 3D Human Pose and Shape from a Single Image
We describe the first method to automatically estimate the 3D pose of the
human body as well as its 3D shape from a single unconstrained image. We
estimate a full 3D mesh and show that 2D joints alone carry a surprising amount
of information about body shape. The problem is challenging because of the
complexity of the human body, articulation, occlusion, clothing, lighting, and
the inherent ambiguity in inferring 3D from 2D. To solve this, we first use a
recently published CNN-based method, DeepCut, to predict (bottom-up) the 2D
body joint locations. We then fit (top-down) a recently published statistical
body shape model, called SMPL, to the 2D joints. We do so by minimizing an
objective function that penalizes the error between the projected 3D model
joints and detected 2D joints. Because SMPL captures correlations in human
shape across the population, we are able to robustly fit it to very little
data. We further leverage the 3D model to prevent solutions that cause
interpenetration. We evaluate our method, SMPLify, on the Leeds Sports,
HumanEva, and Human3.6M datasets, showing superior pose accuracy with respect
to the state of the art.Comment: To appear in ECCV 201
hypersaline infusion protocol through the portal vein may focus electroporation on tumor tissue, but is it really safe? Ppreliminary results
Introduction: irreversible Electroporation (IRE) is highly dependent on the electrical conductivity of the tissue and the high conductivity of tumor tissue, which leads to a lower field than that in the surrounding healthy tissue. Hypersaline Infusion (HI) through the portal vein focuses IRE on scattered liver tumors, by creating a differential conductivity between the different types of tissue. The aim of this study is to determine the effects of the HI protocol on the hepatic and histological biochemical results. Methods: Ten male Sprague Dawley rats were used for HI protocol. Blood samples were collected at pre-, immediately post-, 24-hrs, 72-hrs, 1- week and 3-weeks post-HI. All the animals were sacrificed after a one-month follow-up in order to collect histological samples. Results: The mortality rate in this procedure reached 30% (3/10). Only the pH and transaminases at 24-hrs were significantly and directly linked to mortality (p=0.036 and p=0.004, respectively). The three non-surviving animals had a four-time higher AST level at 24-hrs. Natremianormalized at 24-hrs post-HI. Statistically significant differences were found in hepatic necrosis between the non-surviving (n=3) and surviving rats (n=7) (30.67 ± 10.97 vs. 2.86 ± 7.56% respectively, p=0.01). Discussion: HI through the portal system involves a significant risk of possibly lethal cytolysis and acidosis. Therefore, compensatory measures and a reduced saline overload are warranted to improve the survival rates
One More Awareness Gap? The BehaviourâImpact Gap Problem
Preceding research has made hardly any attempt to measure the ecological impacts of pro-environmental behaviour in an objective way. Those impacts were rather supposed or calculated. The research described herein scrutinized the ecological impact reductions achieved through pro-environmental behaviour and raised the question how much of a reduction in carbon footprint can be achieved through voluntary action without actually affecting the socio-economic determinants of life. A survey was carried out in order to measure the difference between the ecological footprint of âgreenâ and âbrownâ consumers. No significant difference was found between the ecological footprints of the two groupsâsuggesting that individual pro-environmental attitudes and behaviour do not always reduce the environmental impacts of consumption. This finding resulted in the formulation of a new proposition called the BIG (behaviourâimpact gap) problem, which is an interesting addition to research in the field of environmental awareness gaps
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