5,391 research outputs found
The Generalized Point-Vortex Problem and Rotating Solutions to the Gross-Pitaevskii Equation on Surfaces of Revolution
We study the generalized point-vortex problem and the Gross-Pitaevskii
equation on surfaces of revolution. We find rotating periodic solutions to the
generalized point-vortex problem, which have two two rings of equally
spaced vortices with degrees . In particular we prove the existence of
such solutions when the surface is longitudinally symmetric. Then we seek a
rotating solution to the Gross-Pitaevskii equation having vortices that follow
those of the point-vortex flow for sufficiently small
Instability of Ginzburg-Landau Vortices on Manifolds
We investigate two settings of Ginzburg-Landau posed on a manifold where
vortices are unstable. The first is an instability result for critical points
with vortices of the Ginzburg-Landau energy posed on a simply connected,
compact, closed 2-manifold. The second is a vortex annihilation result for the
Ginzburg-Landau heat flow posed on certain surfaces of revolution with
boundary
VIGAN: Missing View Imputation with Generative Adversarial Networks
In an era when big data are becoming the norm, there is less concern with the
quantity but more with the quality and completeness of the data. In many
disciplines, data are collected from heterogeneous sources, resulting in
multi-view or multi-modal datasets. The missing data problem has been
challenging to address in multi-view data analysis. Especially, when certain
samples miss an entire view of data, it creates the missing view problem.
Classic multiple imputations or matrix completion methods are hardly effective
here when no information can be based on in the specific view to impute data
for such samples. The commonly-used simple method of removing samples with a
missing view can dramatically reduce sample size, thus diminishing the
statistical power of a subsequent analysis. In this paper, we propose a novel
approach for view imputation via generative adversarial networks (GANs), which
we name by VIGAN. This approach first treats each view as a separate domain and
identifies domain-to-domain mappings via a GAN using randomly-sampled data from
each view, and then employs a multi-modal denoising autoencoder (DAE) to
reconstruct the missing view from the GAN outputs based on paired data across
the views. Then, by optimizing the GAN and DAE jointly, our model enables the
knowledge integration for domain mappings and view correspondences to
effectively recover the missing view. Empirical results on benchmark datasets
validate the VIGAN approach by comparing against the state of the art. The
evaluation of VIGAN in a genetic study of substance use disorders further
proves the effectiveness and usability of this approach in life science.Comment: 10 pages, 8 figures, conferenc
Refinement treatment of nasal bone fracture: A 6-year study of 329 patients
SummaryBackgroundThe reliability of X-ray radiography for diagnosing nasal bone fractures (NBFs) remains controversial. Recent studies show that, for determining the orientation and location of the displaced/depressed fracture, nasal sonography is as accurate as facial computed tomography. This retrospective study compared conductor-assisted nasal sonography (CANS) to conventional diagnostic tools and reported subjective patient satisfaction and discomfort after closed reduction combined with tube technique.MethodsThis retrospective study reports the results of 329 refinement treatments for nasal bone fracture (including 199 men and 130 women) performed from 2005 to 2011. All patients were assessed with CANS and completed a survey immediately prior to removing the packing. Questionnaires were adapted from the nasal obstruction symptom evaluation (NOSE) scale.ResultsThe study found that CANS has a 97.2% rate of accuracy in diagnosing NBF. The visual analog scale scores of nasal obstruction, nasal congestion, sleep disturbance, trouble breathing, and inability to move air through the nose were analyzed. The experimental group scores were significantly different from the control group for all scores (p < 0.001).ConclusionCompared to conventional methods, CANS is more accurate for detecting NBF. We recommend its use as an alternative tool for diagnosing a nasal fracture. Because the tube technique balances pressure between the nasopharynx and middle ear during swallowing, patient comfort is enhanced. Application of these modifications can improve accuracy in diagnosing NBF and can improve the quality of NBF treatment
Ileocecal Burkitt's Lymphoma Presenting as Ileocolic Intussusception With Appendiceal Invagination and Acute Appendicitis
Intussusception is a common cause of abdominal pain in children. Although most cases are idiopathic, about 10% of cases have a pathologic lead point. Burkitt's lymphoma is not a common etiology. Burkitt's lymphoma might present primarily as intussusception in children but has rarely been associated with appendicitis. We report a case in which a 10-year-old obese boy who initially presented with acute appendicitis due to ileocolic intussusception with appendiceal invagination. He underwent one-trocar laparoscopy and antibiotic treatment. The symptoms recurred 10 days after discharge. Colonoscopy disclosed ileocecal Burkitt's lymphoma as the pathological lead point. This case emphasizes the importance of the age of the patient and the anatomic location of the intussusception related to possible etiology, and hence the most appropriate surgical procedure
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High-Performance Screen-Printed Thermoelectric Films on Fabrics.
Printing techniques could offer a scalable approach to fabricate thermoelectric (TE) devices on flexible substrates for power generation used in wearable devices and personalized thermo-regulation. However, typical printing processes need a large concentration of binder additives, which often render a detrimental effect on electrical transport of the printed TE layers. Here, we report scalable screen-printing of TE layers on flexible fiber glass fabrics, by rationally optimizing the printing inks consisting of TE particles (p-type Bi0.5Sb1.5Te3 or n-type Bi2Te2.7Se0.3), binders, and organic solvents. We identified a suitable binder additive, methyl cellulose, which offers suitable viscosity for printability at a very small concentration (0.45-0.60 wt.%), thus minimizing its negative impact on electrical transport. Following printing, the binders were subsequently burnt off via sintering and hot pressing. We found that the nanoscale defects left behind after the binder burnt off became effective phonon scattering centers, leading to low lattice thermal conductivity in the printed n-type material. With the high electrical conductivity and low thermal conductivity, the screen-printed TE layers showed high room-temperature ZT values of 0.65 and 0.81 for p-type and n-type, respectively
CARS and SHG microscopy to follow the collagen production in living human corneal fibroblasts and mesenchymal stem cells in fibrin gel 3D cultures
Coherent anti-Stokes Raman scattering (CARS) microscopy is combined with
second harmonic generation (SHG) technique in order to follow the early stage
of stem cell differentiation within a 3D scaffold. CARS microscopy can detect
lipid membranes and droplet compartments in living cells and SHG microscopy
enables a strong imaging contrast for molecules with a non-centrosymmetric
ordered structure like collagen. One of the first evidence of hMSCs
differentiation is the formation of an extracellular matrix (ECM) where the
collagen protein is its main component. This work demonstrated the multimodal
CARS and SHG microscopy as a powerful non-invasive label free technique to
investigate the collagen production dynamic in living cell 3D cultures. Its
ability to image the cell morphology and the produced collagen distribution on
a long term (4 weeks) experiment allowed to obtain important information about
the cell-scaffold interaction and the ECM production. The very low limit
reached in detecting collagen has permitted to map even the small amount of
collagen produced by the cells in few hours of culture. This demonstrates
multimodal CARS and SHG microscopy as a novel method to follow cells collagen
production and cells differentiation process. In addition the experiment shows
that the technique is a powerful tool for imaging of very thick sections (about
4 mm). The study conducted on mesenchymal stem cell in fibrin gel cultures
confirmed that differentiation stimulus is induced by the scaffold. The
monitoring of stem cell differentiation within a scaffold in a non-destructive
way will be an important advantage in regenerative medicine and tissue
engineering field.Comment: 15 pages, 5 figures, ECONOS 201
A Robust and Accurate Traveltime Calculation from
We improve the accuracy and stability of
traveltime calculation method using frequency-domain
modeling algorithm. We perform a parameter analysis to
obtain the optimum combination of frequency and damping
factor and thus improve the accuracy of traveltime.
Then we obtain the empirical formula for our numerical
algorithm. Lastly, we propose the adaptive frequency and
the adaptive damping factor for an inhomogeneous model
to eliminate the distortion in the traveltime contour. Twodimensional
numerical examples verify that the proposed
algorithm gives a much smaller traveltime error and a
better traveltime contour for the complex model. Compared
to the other two methods, this algorithm computes
traveltime that is close to a directly transmitted wave. We
demonstrated our algorithm on 2D IFP Marmousi models,
and the numerical results show that our algorithm is a
faster traveltime calculation method of a directly transmitted
wave for imaging the subsurface and transmission
tomography.This study is sponsored by the Chinese State Natural Science Foundation (49825108), the Chinese Academy of Sciences (KZCX2-109 and KZ951-B1-407-02), and the Korea Foundation for Advanced Studies. This work was
also financially supported by the National Laboratory
Project of the Ministry of Science and Technology and
the Brain Korea 21 project of the Ministry of Education
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