scholarly journals SIMULATION OF MULTIPLE PLASMA EDDIES IN 2D

2020 ◽  
Vol 28 (1) ◽  
pp. 95-104
Author(s):  
DANIEL ALVARADO ◽  
FRANCISCO FRUTOS ALFARO
Keyword(s):  
Diffusion Equation ◽  
Stream Function ◽  
Fourth Order ◽  
Plasma Cells ◽  
Two Dimensions ◽  
The Sun ◽  
Magnetic Diffusion ◽  
Order Scheme ◽  
Convective Cells

In this contribution, we present the simulations of convective plasma cells of the Sun in two dimensions. With a simple stream function, it is possible to visualize multiple n × n convective cells. To obtain the simulation, we solve the magnetic diffusion equation with a fourth order scheme. Some applications for this simulations are also presented.

scholarly journals Robust nonconforming virtual element methods for general fourth-order problems with varying coefficients

2021 ◽  
Author(s):  
Andreas Dedner ◽  
Alice Hodson
Keyword(s):  
Fourth Order ◽  
Perturbation Parameter ◽  
Two Dimensions ◽  
Optimal Error Estimates ◽  
Projection Operators ◽  
Varying Coefficients ◽  
Virtual Element Methods ◽  
Virtual Element ◽  
Perturbation Problems ◽  
Fourth Order Problems

Abstract We present a class of nonconforming virtual element methods for general fourth-order partial differential equations in two dimensions. We develop a generic approach for constructing the necessary projection operators and virtual element spaces. Optimal error estimates in the energy norm are provided for general linear fourth-order problems with varying coefficients. We also discuss fourth-order perturbation problems and present a novel nonconforming scheme which is uniformly convergent with respect to the perturbation parameter without requiring an enlargement of the space. Numerical tests are carried out to verify the theoretical results. We conclude with a brief discussion on how our approach can easily be applied to nonlinear fourth-order problems.

scholarly journals Differences in Clinical Features and Diagnostic Strategies Between IgG4-Related Autoimmune Cholangitis and Cholangiocarcinoma

2021 ◽  
Vol 11 ◽  
Author(s):  
Ke Zhu ◽  
Jin Yang ◽  
Ying-zhen Chen ◽  
Xue-rong Zhang ◽  
Xian-huan Yu ◽  
...  
Keyword(s):  
Ct Scan ◽  
Surgical Resection ◽  
Plasma Cells ◽  
Diagnostic Value ◽  
The Sun ◽  
Autoimmune Cholangitis ◽  
Diagnostic Strategies ◽  
Preoperative Diagnostic ◽  
Clinical Strategy

IgG4-related autoimmune cholangitis (IgG4-AIC) is often difficult to distinguish from cholangiocarcinoma (CCA). This study aimed to determine a practical clinical strategy for distinguishing between IgG4-AIC and CCA to avoid unnecessary surgical resection. We retrospectively collected and compared the clinicopathological data between IgG4-AIC and CCA patients, including the clinical, serological, and radiological characteristics, to follow up on these patients to investigate the prognosis. Among the 377 patients who received surgical resection for suspecting CCA at the Sun Yat-Sen Memorial Hospital between June 2004 and June 2014, 14 patients were diagnosed as IgG4-AIC through histochemistry after surgery. Immunohistochemistry revealed that IgG4 was up-regulated in the plasma cells of IgG4-AIC tissues in 13 out of 14 patients. The serum CA19-9 level was significantly lower than in the CCA group. Patients with IgG4-AIC can only see slight or no enhancement under the contrast enhancement CT scan, while there are no signs of ring-like or delayed enhancement that is unique to CCA. Thirteen patients were followed up, and the time was 12 to 92 months. Three of them were regularly treated with prednisone after surgery, and original symptoms disappeared. Our study demonstrated that the combination of imaging with serum CA19-9 could improve the preoperative diagnostic value and reduce the rate of unnecessary resection.

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