scholarly journals On generalized donating regions: Classifying Lagrangian fluxing particles through a fixed curve in the plane

2015 ◽  
Vol 424 (2) ◽  
pp. 861-877 ◽  
Author(s):  
Qinghai Zhang
Keyword(s):  
1950 ◽  
Vol 1 ◽  
pp. 19-23
Author(s):  
Minoru Kurita

On the euclidean plane one-parametric motion is in general a roulett motion, exceptions being a translation at each instant and a rotation with a fixed center; here we mean by a roulett motion a motion in which a certain curve rolls on another fixed curve without slipping. In this paper we extend this fact to the case of Klein spaces and investigate in detail especially the cases of the euclidean space and the projective space.


Author(s):  
Paweł Jarczyk ◽  
Vladimir Mityushev

We discuss the conductivity of two-dimensional media with coated neutral inclusions of finite conductivity. Such an inclusion, when inserted in a matrix, does not disturb the uniform external field. We are looking for shapes of the core and coating in terms of the conformal mapping ω ( z ) of the unit disc onto coated inclusions. The considered inverse problem is reduced to an eigenvalue problem for an integral equation containing singular integrals over a closed curve L 1 on the transformed complex plane. The conformal mapping ω ( z ) is constructed via eigenfunctions of the integral equation. For each fixed curve L 1 , the boundary of the core is given by the curve ω ( L 1 ). The boundary of the coating is obtained by the mapping of the unit circle. It is justified that any shaped inclusion with a smooth boundary can be made neutral by surrounding it with an appropriate coating. Shapes of the neutral inclusions are obtained in analytical form when L 1 is an ellipse.


2020 ◽  
Vol 28 (2) ◽  
pp. 173-184 ◽  
Author(s):  
Rohit Kumar Mishra

AbstractWe show that a vector field in {\mathbb{R}^{n}} can be reconstructed uniquely from the knowledge of restricted Doppler and first integral moment transforms. The line complex we consider consists of all lines passing through a fixed curve {\gamma\subset\mathbb{R}^{n}}. The question of reconstruction of a symmetric m-tensor field from the knowledge of the first {m+1} integral moments was posed by Sharafutdinov [Integral Geometry of Tensor Fields, Inverse Ill-posed Probl. Ser. 1, De Gruyter, Berlin, 1994, p. 78]. In this work, we provide an answer to Sharafutdinov’s question for the case of vector fields from restricted data comprising of the first two integral moment transforms.


SIAM Review ◽  
2013 ◽  
Vol 55 (3) ◽  
pp. 443-461 ◽  
Author(s):  
Qinghai Zhang
Keyword(s):  

1951 ◽  
Vol 2 ◽  
pp. 55-61 ◽  
Author(s):  
Minoru Kurita

A curve c2 of finite length L2 moves on a euclidean plane. Let the number of points of intersection of c2 with the fixed, curve C1 of length Ls1 be n, and the element of kinematic measure of the position of c2 be dK.


1910 ◽  
Vol 29 ◽  
pp. 65-74
Author(s):  
John Miller
Keyword(s):  

The surfaces here considered were first discussed by Monge as surfaces whose normals are tangents to given developables. Under the name general surfaces moulures, Darboux treats them as the surfaces traced out by a fixed curve on a plane which rolls on a developable. When the developable is a cylinder he gives the general coordinates in his Leçons sur la Theorie Generale des Surfaces (Volume I., page 105). This led me to take up the more general case, but I later found that Darboux had also considered this in an ingenious and elegant manner in his Leçons sur les Systèmes Orthogonaux et les Coordonnées Curvilignes (Tome 1, pages 26–34). Perhaps this quite difFerent discussion will present some interesting points in analysis.


2014 ◽  
Vol 121 (4) ◽  
pp. 719-729 ◽  
Author(s):  
Darsim L. Haji ◽  
Mohamed M. Ali ◽  
Alistair Royse ◽  
David J. Canty ◽  
Sandy Clarke ◽  
...  

Abstract Background: Left atrial pressure and its surrogate, pulmonary capillary wedge pressure (PCWP), are important for determining diastolic function. The role of transthoracic echocardiography (TTE) in assessing diastolic function is well established in awake subjects. The objective was to assess the accuracy of predicting PCWP by TTE and transesophageal echocardiography (TEE) during coronary artery surgery. Methods: In 27 adult patients undergoing on-pump coronary artery surgery, simultaneous echocardiographic and hemodynamic measurements were obtained immediately before anesthesia (TTE), after anesthesia and mechanical ventilation (TTE and TEE), during conduit harvest (TEE), and after separation from cardiopulmonary bypass (TEE). Results: Twenty patients had an ejection fraction (EF) of 0.5 or greater. With the exception of E/e′ and S/D ratios, echocardiographic values changed over the echocardiographic studies. In patients with low EF, E velocity, deceleration time, pulmonary vein D, S/D, and E/e′ ratios correlated well with PCWP before anesthesia. After induction of anesthesia using TTE or TEE, correlations were poor. In normal EF patients, correlations were poor for both TEE and TTE at all five stages. The sensitivity and specificity of echocardiographic values were not high enough to predict raised PCWP except for a fixed curve pattern of interatrial septum (area under the curve 0.89 for PCWP ≥17, and 0.98 for ≥18 mmHg) and S/D less than 1 (area under the curve 0.74 for PCWP ≥17, and 0.78 for ≥18 mmHg). Conclusion: Doppler assessment of PCWP was neither sensitive nor specific enough to be clinically useful in anesthetized patients with mechanical ventilation. The fixed curve pattern of the interatrial septum was the best predictor of raised PCWP.


EP Europace ◽  
2020 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
D Duncker ◽  
M Svetlosak ◽  
F Guerra ◽  
K V Nagy ◽  
P Vanduynhoven ◽  
...  

Abstract Introduction Reprocessing of electrophysiology (EP) catheters in daily routine varies through countries and may depend on national laws, catheter (cath.) models or supplier. Data on reprocessing of EP materials is sparse and remains a matter of controversy. The aim of this study is to collect data on reprocessing usage through EHRA countries. Methods and results A structured online questionnaire comprising 27 questions was distributed among electrophysiologists in EHRA countries. Two-hundred-and-two participants from 34 countries completed the survey (161 males, 36.8 ± 5.8 years old). Overall, 111 (55%) of respondents currently use reprocessed materials and 30 (15%) have used them in the past. Cables, diagnostic cath. with deflectable curve and diagnostic cath. with fixed curve were the most frequently reprocessed materials (87%, 80% and 78% respondents, respectively). Maximum number of times (median) a cath. was usually reprocessed was 6 for diagnostic cath. and 5 for ablation cath. Among potential benefits of reprocessing, cost reduction for the providing hospital (65%), cost reduction for the health provider (42%) and making EP procedure available for more patients (42%) were most frequently reported. Respondents reported a need to change the reprocessed material due to its insufficient functionality in around 15% of cases. They were also concerned about the quality of the reprocessed material (58%), contamination issues (52%) and loss of precision (47%). Nineteen (17%) users of reprocessed EP material reported at least one complication potentially related to the reprocessing during their whole reprocessing experience. Sixty-six (73%) respondents who did not use reprocessed EP material would consider using it in the future. Conclusions Reprocessing of EP material is heterogeneously managed among the EHRA countries, as wide differences are present in terms of national and local regulations, clinical practice and technical aspects. Nonetheless, the current data show that European electrophysiologists consider the use of reprocessed EP material as generally safe and cost-effective.


2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
F Zanon ◽  
L Marcantoni ◽  
G Pastore ◽  
E Baracca ◽  
C Picariello ◽  
...  

Abstract Background His bundle pacing (HBP) can be affected by high thresholds and low sensing. Thus, in selected patients including a back-up lead is advisable. Objective Single-centre retrospective analysis of a large HBP experience, focusing on the back-up lead utilization over the years. Methods 677 pts (76±8 years; 433 males) were implanted with HBP from 2004 to 2019 July. The pts received S-HBP (67%) or NS-HBP by the 3830 lead. The pacing indications were AV block 54%, sinus node disease 17%, slow atrial fibrillation 23%, heart failure 6%. Ischemic cardiopathy was found in 26%; hypertension in 83%, diabetes in28% pts. Baseline QRS duration was 123±32 ms and EF 56±12%. Results 266 (39%) pts received the back-up lead. In sinus rhythm we implanted 3-chamber PM (His lead:LV port; VV delay 80 ms: His pulses and apical pacing during the refractory period). 30 pts (11%) received a particular type of 3-chamber PM which provides back-up pacing only if His capture fails, thus saving energy. In atrial fibrillation 2-chamber PM was implanted (His lead: atrial port, DVI). We recorded a significant decrease of back-up lead use over the years, strictly related to operators/centre experience (>70% during the first years, nearly 10% during the last year). The C315 fixed curve sheath, strongly contributed to the rapid reduction of back-up lead use thanks to better lead fixation and stability. Conclusion The back-up lead utilization is progressively decreasing. It is strictly related to the operator/centre experience. The presence of the back-up lead could strengthen the Hisian pacing reliability, potentially impacting pacing indication even in advanced conduction disturbances and saving device longevity. Funding Acknowledgement Type of funding source: None


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