1,738 research outputs found
A FETI method with a mesh independent condition number for the iteration matrix
We introduce a framework for FETI methods using ideas from the
decomposition via Lagrange multipliers of H1 0 (Ω) derived by Raviart-Thomas [22] P.-A. Raviart, J.-M. Thomas, Primal Hybrid Finite Element Metho and complemented with the detailed work on polygonal domains developed by Grisvard [17] P. Grisvard, Singularities in Boundary value problems. Recherches en Mathématiques Appliquées, 22. Masson, 1992.. We compute the action of the Lagrange multipliers using the natural H 1/2 00 scalar product, therefore no consistency error appears. As a byproduct, we obtain that the condition number for the iteration matrix is independent of the mesh size and there is no need for preconditioning. This result improves the standard asymptotic bound for this condition number shown by Mandel-Tezaur in [19] J. Mandel, R. Tezaur, Convergence of a substructuring method with Lagrange multipliers. Numer. Math., 73 (1996), 473–487. Numerical results that confirm our theoretical analysis are presented.Nous proposons une nouvelle approche des méthodes FETI: la décomposition de domaine fait appel aux multiplicateurs de Lagrange tels
qu’introduits par Raviart-Thomas [22] P.-A. Raviart, J.-M. Thomas, Primal Hybrid Finite Element Methods for second order eliptic equations. Math. Comp., 31 (1977), 391-413 et au traitement des domaines polygonaux
dù á Grisvard [17] P. Grisvard, Singularities in Boundary value problems. Recherches en Mathématiques Appliquées, 22. Masson, 1992. Ces multiplicateurs utilisent le produit scalaire de H 1/2 00, de sorte qu’aucune erreur de consistance n’apparaît. En outre, nous prouvons que le nombre de condition de la matrice liée à chaque itération est indépendant de la taille du maillage, ce qui améliore le résultat de Mandel-Tezaur [19] J. Mandel, R. Tezaur, Convergence of a substructuring method with Lagrange
multipliers. Numer. Math., 73 (1996), 473–487; par suite, aucun préconditionnement n’est nécessaire. Nous présentons des expériences numériques qui confirment notre analyse.Ministerio de Educación y Cienci
Assessment of quality of life in patients on antiepileptic drugs: a hospital based cross sectional study
Background: Quality of life (QOL) is a broad, multidimensional concept that usually includes subjective evaluations of both positive and negative aspects of life. Very few studies have been carried out on QOLIE 31 in India and research in this area will identify factors affecting QOL. study was therefore conducted to determine the level of health related QOL of patients of epilepsy in a tertiary care teaching hospital. To evaluate patterns of the use of anti-epileptic drugs (AEDs) and their impact on the Quality of Life (QOL) in patients with epilepsy.Methods: The study was a hospital based cross sectional study conducted by the Department of Pharmacology in association with the Department of Medicine, Government Medical College, Srinagar. A total number of 134 patients, aged >18 years were studied for a period of one and a half years, January 2015-July 2016. QOLIE‑31 questionnaire was used for collecting data on health‑related QOL.Results: The mean overall QOLIE-31 score was 53 corresponding to a t-score of 44. Amongst the QOLIE-31 subscales, the highest mean score was the cognitive subscale (73.6) followed by medication effects (55.5) and social functions (52).Conclusions: It is evident from our study that there are many factors that influence QOL of people with epilepsy. Among them, type of drug therapy plays an important role. Adding clinical counselling and other interventions to address the physical, mental, psychological, social, and emotional aspects of health wellbeing is likely to achieve better health outcomes for epilepsy patients
Genetic diversity in modern T. Aman Rice varieties of Bangladesh (Oryza sativa L.)
A field experiment was conducted from June to December, 2013 to study the genetic diversity of 15 modern T. Aman rice varieties of Bangladesh (Oryza sativa L.) with a view to assess the superior genotype in future hybridization program for developing new rice varieties that is suitable for the target environment. Analysis of variance for each trait showed significant differences among the varieties. High heritability associated with high genetic advance in percent of mean was observed for plant height and thousand seed weight which indicated that selection for these characters would be effective. Hence, thrust has to be given for these characters in future breeding program to improve the yield trait in rice. Multivariate analysis based on 10 agronomic characters indicated that the 15 varieties were grouped into four distant clusters. The inter cluster distance was maximum between cluster II and cluster IV. The highest intra-cluster distance was found in cluster IV. Based on positive value of vector 1 and vector 2, plant height and 1000-seed weight had maximum contribution towards genetic divergence. From the results, it can be concluded that the varieties BRRI dhan40, BRRI dhan44, BRRI dhan46, BRRI dhan49 and BINA dhan7 may be selected for future hybridization program
Analisa Biomassa Dan Kandungan Logam Berat Pada Beras Merah Hasil Pemupukan Kompos Sludge Dari Pabrik Kertas Dan Pulp
Pabrik kertas dan pulp menghasilkan limbah cair dan limbah padat (sludge). Limbah cair dikelolamelalui instalansi pengelolaan air limbah (IPAL), sedangkan sludge hanya di timbun dalam tanah.Upaya yang dilakukan untuk mengelola sludge adalah diubah menjadi pupuk melaluipengomposan, karena sludge mengandung unsur hara yang dibutuhkan oleh tanaman. Penelitian inibertujuan menguji kandungan logam berat yang terdapat pada sampel padi merah hasil pemupukankompos sludge yang diperoleh dari penelitian sebelumnya. Dari tanaman padi merah terlebihdahulu dilakukan uji biomassa, selanjutnya dilakukan pengujian kadar protein dan kadar logam,terhadap beras merah. Analisis kandungan protein dengan metode Kjedahl dan pengukurankonsentrasi logam dan logam berat dengan metode spektrofotometer serapan atom. Hasil penelitianmenunjukkan bahwa padi merah hasil pemupukan kompos sludge memiliki biomassa yang lebihtinggi dari pada kontrol (yang tidak dilakukan pemupukan kompos sludge). Peningkatan optimalbiomassa dan kadar protein pada pemupukan kompos sludge 3 kg/m2 yaitu 78 gram dan 11,1%.Biomassa tanaman padi meningkat sebanyak 20 gram (dari 58 gram menjadi 78 gram) ketika padapemupukan kompos sludge 0 kg/m2 menjadi 3 kg/m2. Kandungan protein beras merah meningkatsebanyak 2,8% (dari 8,3% menjadi 11%) ketika pada pemupukan kompos sludge 0 kg/m2 menjadi3 kg/m2. Hasil analisis logam pada beras merah menunjukkan penambahan dosis kompos sludgetidak menaikkan kandungan logam (α = 0,05). Kandungan logam Cu, Zn, Mn dan Fe berturut-turut2,41 ppm; 7,77 ppm; 32,7 ppm dan 37,71 ppm. Kandungan logam Cu dan Zn yang teranalisismasih aman untuk beras. Logam berat seperti Pb, Cd dan Cr tidak terdeteksi walaupun pada sampelyang pemupukannya 4,5 kg/m2
Imaging Biomarkers for Precision Medicine in Locally Advanced Breast Cancer
Guidelines from the American National Comprehensive Cancer Network (NCCN)recommend neoadjuvant chemotherapy (NAC) to patients with locally advanced breast cancer (LABC) to downstage tumors before surgery. However, only a small fraction (15-17%) of LABC patients achieve complete pathologic response (pCR), i.e. no residual tumor in the breast, after treatment. Measuring tumor response during
53 neoadjuvant chemotherapy can potentially help physicians adapt treatment thus, potentially improving the pCR rate. Recently, imaging biomarkers that are used to measure the tumor’s functional and biological features have been studied as pre-treatment markers for pCR or as an indicator for intra-treatment tumor response. Also, imaging biomarkers have been the focus of intense research to characterize tumor heterogeneity as well as to advance our understanding of the principle mechanisms behind chemoresistance. Advances in investigational radiology are moving rapidly to high-resolution imaging, capturing metabolic data, performing tissue characterization and statistical modelling of imaging biomarkers, with an endpoint of personalized medicine in breast cancer treatment. In this commentary, we present studies within the framework of imaging biomarkers used to measure breast tumor response to chemotherapy. Current studies are showing that significant progress has been made in the accuracy of measuring tumor response either before or during chemotherapy, yet the challenges at the forefront of these works include translational gaps such as needing large-scale clinical trials for validation, and standardization of imaging methods. However, the ongoing research is showing that imaging biomarkers may play an important role in personalized treatments for LABC
Recent advances in parametric nonlinear model order reduction: treatment of shocks, contact and interfaces, structure-preserving hyper reduction, acceleration of multiscale formulations, and application to design optimization
International audienceParametric, projection-based, Model Order Reduction (MOR) is a mathematical tool for constructing a parametric Reduced-Order Model (ROM) by projecting a given parametric High Dimensional Model (HDM) onto a Reduced-Order Basis (ROB). It is rapidly becoming indispensable for a large number of applications including, among others, computational-based design and optimization, multiscale analysis, statistical analysis, uncertainty quantification, and model predictive control. It is also essential for scenarios where real-time simulation responses are desired. During the last two decades, linear, projection-based, parametric MOR has matured and made a major impact in many fields of engineering including electrical engineering, acoustics, and structural acoustics, to name only a few. By comparison, nonlinear, projection-based, parametric MOR remains somehow in its infancy. Nevertheless, giant strides have been recently achieved in many of its theoretical, algorithmic, and offline/online organizational aspects. The main purpose of this lecture is to highlight some of these advances, discuss their mathematical and computer science underpinnings, and report on their impact for an important class of problems in aerodynamics, fluid mechanics, nonlinear solid mechanics and structural dynamics, failure analysis, multiscale analysis, uncertainty quantification, and design optimization. To this effect, nonlinear, projection-based, parametric MOR will be first interpreted as a constrained semidiscretization on a subset of a compact Stiefel manifold, using a low-dimensional basis of global shape functions constructed a posteriori — that is, after some knowledge about the response of the system of interest has been developed. Usually, such a knowledge is gathered using the given parametric HDM and an offline training procedure where the model parameters are sampled with a greedy strategy based on a cost-effective ROM error indicator. Specifically, a set of problems related to the parametric problem of interest are solved at the sampled parameter points using the given HDM, and the computed solution snapshots are compressed to obtain the desired global ROB. Depending on the mathematical type of the governing equations underlying the given HDM, a dual ROB is also constructed and the sought-after nonlinear parametric ROM is constructed by Galerkin (or Petrov-Galerkin) projection of the HDM onto the global ROB (and its dual counterpart)
The effects of phosphanegold(I) thiolates on the biological properties of Acanthamoeba castellanii belonging to the T4 genotype
BACKGROUND: Gold compounds have shown promise in the treatment of non-communicable diseases such as rheumatoid arthritis and cancer, and are considered of value as anti-microbial agents against Gram-negative and Gram-positive bacteria, and have anti-parasitic properties against Schistosoma mansoni, Trypanosoma brucei, Plasmodium falciparum, Leishmania infantinum, Giardia lamblia, and Entamoeba histolytica. They are known to affect enzymatic activities that are required for the cellular respiration processes. METHODS: Anti-amoebic effects of phosphanegold(I) thiolates were tested against clinical isolate of A. castellanii belonging to the T4 genotype by employing viability assays, growth inhibition assays, encystation assays, excystation assays, and zymographic assays. RESULTS: The treatment of A. castellanii with the phosphanegold(I) thiolates tested (i) had no effect on the viability of A. castellanii as determined by Trypan blue exclusion test, (ii) did not affect amoebae growth using PYG growth medium, (iii) did not inhibit cellular differentiation, and (iv) had no effect on the extracellular proteolytic activities of A. castellanii. CONCLUSION: Being free-living amoeba, A. castellanii is a versatile respirator and possesses respiratory mechanisms that adapt to various aerobic and anaerobic environments to avoid toxic threats and adverse conditions. For the first time, our findings showed that A. castellanii exhibits resistance to the toxic effects of gold compounds and could prove to be an attractive model to study mechanisms of metal resistance in eukaryotic cells
Is there an optimal minimally invasive technique for left anterior descending coronary artery bypass?
<p>Abstract</p> <p>Background</p> <p>The aim of this retrospective study was to evaluate the clinical outcome of three different minimally invasive surgical techniques for left anterior descending (LAD) coronary artery bypass grafting (CABG): Port-Access surgery (PA-CABG), minimally invasive direct CABG (MIDCAB) and off-pump totally endoscopic CABG (TECAB).</p> <p>Methods</p> <p>Over a decade, 160 eligible patients for elective LAD bypass were referred to one of the three techniques: 48 PA-CABG, 53 MIDCAB and 59 TECAB. In MIDCAB group, Euroscore was higher and target vessel quality was worse. In TECAB group, early patency was systematically evaluated using coronary CT scan. During follow-up (mean 2.7 ± 0.1 years, cumulated 438 years) symptom-based angiography was performed.</p> <p>Results</p> <p>There was no conversion from off-pump to on-pump procedure or to sternotomy approach. In TECAB group, there was one hospital cardiac death (1.7%), reoperation for bleeding was higher (8.5% vs 3.7% in MIDCAB and 2% in PA-CABG) and 3-month LAD reintervention was significantly higher (10% vs 1.8% in MIDCAB and 0% in PA-CABG). There was no difference between MIDCAB and PA-CABG groups. During follow-up, symptom-based angiography (n = 12) demonstrated a good patency of LAD bypass in all groups and 4 patients underwent a no LAD reintervention. At 3 years, there was no difference in survival; 3-year angina-free survival and reintervention-free survival were significantly lower in TECAB group (TECAB, 85 ± 12%, 88 ± 8%; MIDCAB, 100%, 98 ± 5%; PA-CABG, 94 ± 8%, 100%; respectively).</p> <p>Conclusions</p> <p>Our study confirmed that minimally invasive LAD grafting was safe and effective. TECAB is associated with a higher rate of early bypass failure and reintervention. MIDCAB is still the most reliable surgical technique for isolated LAD grafting and the least cost effective.</p
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