A posteriori error estimators for nonconforming finite element methods of the linear elasticity problem

AbstractIn this work we derive and analyze a posteriori error estimators for low-order nonconforming finite element methods of the linear elasticity problem on both triangular and quadrilateral meshes, with hanging nodes allowed for local mesh refinement. First, it is shown that equilibrated Neumann data on interelement boundaries are simply given by the local weak residuals of the numerical solution. The first error estimator is then obtained by applying the equilibrated residual method with this set of Neumann data. From this implicit estimator we also derive two explicit error estimators, one of which is similar to the one proposed by Dörfler and Ainsworth (2005) [24] for the Stokes problem. It is established that all these error estimators are reliable and efficient in a robust way with respect to the Lamé constants. The main advantage of our error estimators is that they yield guaranteed, i.e., constant-free upper bounds for the energy-like error (up to higher order terms due to data oscillation) when a good estimate for the inf–sup constant is available, which is confirmed by some numerical results

Maximum entropy classification for record linkage

By record linkage one joins records residing in separate files which are believed to be related to the same entity. In this paper we approach record linkage as a classification problem, and adapt the maximum entropy classification method in machine learning to record linkage, both in the supervised and unsupervised settings of machine learning. The set of links will be chosen according to the associated uncertainty. On the one hand, our framework overcomes some persistent theoretical flaws of the classical approach pioneered by Fellegi and Sunter (1969); on the other hand, the proposed algorithm is fully automatic, unlike the classical approach that generally requires clerical review to resolve the undecided cases.Maximum entropy classification for record linkagepublishedVersio

Convective-scale hybrid data assimilation over the Maritime continent

Data assimilation is an important component of numerical weather prediction (NWP); it is used to estimate realistic initial conditions. In recent years, hybrid data assimilation, which combines the traditional climatological representation of background error covariances with an ensemble representation, has gained significant traction. This thesis develops and applies hybrid ensemble-variational data assimilation to a convective-scale tropical simplified model (ABC-DA) and an NWP system over the western Maritime Continent (SINGV-DA) to explore its benefits and how it can be better designed for the tropics. Firstly, the hybrid ensemble-variational data assimilation approach (hybrid-En3DVar) was implemented in ABC-DA. Generally, hybrid-En3DVar outperformed the traditional 3DVar data assimilation approaches. The improvements were sensitive to ensemble size, and were less pronounced when the ensemble was very small. The results also highlighted how the sub-optimal background error covariance model in 3DVar, which uses geostrophic balance as a balance constraint, led to erroneous analysis increments in meridional wind and negatively impacted the forecasts. Secondly, the hybrid ensemble-variational data assimilation approach was implemented in SINGV-DA. Without proper tuning, the initial hybrid-En3DVar setup had a relatively neutral impact compared to 3DVar. However, tuning the weightings for hybrid-En3DVar and time-shifting of ensemble perturbations were vital for improving precipitation forecasts and forecast fits to radiosonde humidity and wind compared to 3DVar. The results also highlighted how the autocovariance structures varied between variables, including the presence of robust cross-correlation structures between the moisture and temperature-related variables in the ensemble-derived background error matrix, which could have physical significance over the Maritime Continent. Thirdly, the localisation aspect of En3DVar was modified to allow for variable-dependent localisation (prescribing different localisation length-scales for different variables) and selective multivariate localisation (knocking-out by localisation certain multi-variate error covariances) in ABC-DA. This was to address two limitations of traditional ensemble-variational data assimilation approaches which were pertinent over the tropics. Using selective multivariate localisation was beneficial, particularly when covariances associated with hydrostatic balance were retained and when zonal wind errors were de-coupled from the mass errors in the cross-covariances. The results also showed that variable-dependent localisation could be beneficial if the localisation length-scales were well-tuned for each variable. Both these enhancements within a pure EnVar framework reduced the forecast root-mean-square errors by about 3-4% for zonal wind and mass variables. These benefits may also apply to hybrid-En3DVar

THE DESIGN OF A DUAL-POLARIZED SMALL BASE STATION ANTENNA WITH HIGH ISOLATION HAVING DIELECTRIC FEEDING STRUCTURE

Abstract-A dual-polarized small base station antenna with a dielectric feeding structure is presented. The proposed antenna is composed of a micro-strip feed line board, eight metallic shorting plates, four dielectric feed substrates, four metallic radiators, a metallic cube, and a radome. A wide impedance bandwidth of 20% (2.45 to 3.0 GHz) is achieved. The proposed antenna has an isolation of greater than 50 dB over the operating bandwidth. Details of the proposed antenna design, and the simulated and measured results are presented and discussed

EFFECT OF SALT (NACL) STRESS ON GERMINATION AND EARLY SEEDLING GROWTH OF FOUR VEGETABLES SPECIES

Due to increasing salinity problems, in this experiment four vegetables species were treated with different concentration of salt solution to study salt effect. Results indicated that salinity caused signifi cant reduction in germination percentage, germination rate, root and shoot lengths and fresh root and shoot weights. Liner relation was developed to fi nd relation between salt stress and plant growth and also between germination and rest of plant characters

Cleavage of Cdc6 by caspase-3 promotes ATM/ATR kinase–mediated apoptosis of HeLa cells

We show that caspase-3 cleaves Cdc6 at D290/S and D442/G sites, producing p32-tCdc6 (truncated Cdc6) and p49-tCdc6, respectively, during etoposide- or tumor necrosis factor (TNF)-α–induced apoptosis. The expression of these tCdc6 proteins, p32- and p49-tCdc6, promotes etoposide-induced apoptosis. The expression of tCdc6 perturbs the loading of Mcm2 but not Orc2 onto chromatin and activates ataxia telangiectasia mutated (ATM) and ATM and Rad-3 related (ATR) kinase activities with kinetics similar to that of the phosphorylation of Chk1/2. The activation kinetics are consistent with elevated cellular levels of p53 and mitochondrial levels of Bax. The tCdc6-induced effects are all suppressed to control levels by expressing a Cdc6 mutant that cannot be cleaved by caspase-3 (Cdc6-UM). Cdc6-UM expression attenuates the TNF-α–induced activation of ATM and caspase-3 activities. When ATM or ATR is down-expressed by using the small interfering RNA technique, the TNF-α– or tCdc6-induced activation of caspase-3 activities is suppressed in the cells. These results suggest that tCdc6 proteins act as dominant-negative inhibitors of replication initiation and that they disrupt chromatin structure and/or induce DNA damage, leading to the activation of ATM/ATR kinase activation and p53–Bax-mediated apoptosis

Factors associated with stroke in patients with paroxysmal atrial fibrillation beyond CHADS2 score

Background: This study was conducted to investigate factors associated with stroke in pa­tients with paroxysmal atrial fibrillation (PAF) beyond CHADS2 score in terms of left ventricular (LV) diastolic function or left atrial (LA) function. Methods: One hundred and sixty-one patients with PAF and age less than 75 (mean age 61 ± 10; 69 male) who underwent transthoracic echocardiography were investigated. Patients were divided into two groups according to the stroke status (group 1 — no stroke vs. group 2 — presence of stroke). Baseline echocardiographic parameters and LA segmental (4 segments: basal septal, lateral, inferior, and anterior) strain rate (SR) during normal sinus rhythm were analyzed. Results: CHAD score (except S2) was similar between the two groups (0.6 ± 0.7 vs. 0.9 ± 0.7, p = 0.125). Patients with stroke had slightly lower body mass index (24.5 ± 2.7 vs. 23.4 ± ± 2.4, p = 0.052). Echocardiographic parameters did not show any differences in both systolic and diastolic functions between the two groups, however elevated E/E’ ratio was noted (9.5 ± ± 3.8 vs. 11.6 ± 3.9, p = 0.010) due to higher E velocity (63.5 ± 15.9 vs. 70.9 ± 16.0 cm/s, p = 0.046). In the analysis of LA SR, there are no differences of SR among the 4 segments. However, standard deviations (SD) of time to peak SR (SD of tA-SR) of the 4 segments were higher in patients with stroke (10.9 ± 9.9 vs. 22.1 ± 18.1 ms, p = 0.009) which indicates dyssynchronous contraction of LA. In multivariate analysis, SD of tA-SR (OR 1.074, CI 1.024–1.128, p = 0.004) and elevated E/E’ (OR 1.189, CI 1.006–1.406, p = 0.048) were independently associated with stroke in patients with PAF. Conclusions: Elevated E velocity, E/E’ and SD of tA-SR were associated with occurrence of stroke in patients with PAF even with similar CHAD scores. Increased SD of tA-SR and E/E’ were independently associated with stroke in patients with PAF.

Psoralea corylifolia

Pancreatic beta-cell death is known to be the cause of deficient insulin production in diabetes mellitus. Oxidative stress is one of the major causes of beta-cell death. In this study, we investigated the effects of Psoralea corylifolia L. seed (PCS) extract on beta-cell death. Oral administration of PCS extract resulted in a significant improvement of hyperglycemia in streptozotocin-induced diabetic mice. PCS extract treatment improved glucose tolerance and increased serum insulin levels. To study the mechanisms involved, we investigated the effects of PCS extract on H2O2-induced apoptosis in INS-1 cells. Treatment with PCS extract inhibited cell death. PCS extract treatment decreased reactive oxygen species level and activated antioxidative enzymes. Among the major components of PCS extract, psoralen and isopsoralen (coumarins), but not bakuchiol, showed preventive effects against H2O2-induced beta-cell death. These findings indicate that PCS extract may be a potential pharmacological agent to protect against pancreatic beta-cell damage caused by oxidative stress associated with diabetes

Haddad Syndrome with PHOX2B Gene Mutation in a Korean Infant

Congenital central hypoventilation syndrome with Hirschsprung's disease, also known as Haddad syndrome, is an extremely rare disorder with variable symptoms. Recent studies described that congenital central hypoventilation syndrome had deep relation to the mutation of the PHOX2B gene in its diagnosis and phenotype. We report a newborn male infant with clinical manifestations of recurrent hypoventilation with hypercapnea and bowel obstruction. These clinical manifestations were compatible with congenital central hypoventilation syndrome and Hirschsprung's disease, and polyalanine 26 repeats in the PHOX2B gene supported the diagnosis of congenital central hypoventilation. We described a first case of Haddad syndrome in Korean and its clinical and genetic characteristics were discussed