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Mixed Form (mixed + form)
Selected AbstractsCarotid Sinus Hypersensitivity is Common in Patients Presenting with Hip Fracture and Unexplained FallsPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 9 2009M.Sc., VASILEIOS SACHPEKIDIS M.D. Background:We tried to determine the prevalence of carotid sinus hypersensitivity (CSH) in patients with hip fractures with and without a clear history of an accidental fall. Methods:We studied 51 patients hospitalized for a hip fracture and 51 matched controls from our outpatients department. All patients were subjected to a carotid sinus massage in the supine and upright position. Patients were categorized in accidental (Group A) and unexplained (Group B) fallers. Results:Six of 33 (18.2%) patients in Group A and 12 of 18 (66.7%) patients in Group B (P < 0.001) had a positive response to the carotid sinus massage. Nine controls (17.6%) also demonstrated CSH. Patients in Group B were older (A: 75.5 ± 8.5 years vs B: 80.1 ± 5.9 years, P =0.029) and were more likely to have a history of unexplained falls or syncope in the past (A: 0% vs B: 66.7%, P < 0.0001) than individuals in group A. Vasodepressor/mixed forms accounted for the majority of CSH responses in Group B (75%). When compared with the control group, CSH was still more common in Group B (B: 66.7% vs control: 17.6%, P < 0.0001) but not in Group A (A: 18.2% vs control: 17.6%, P =1.000). Conclusions:The prevalence of CSH is increased in elderly patients with hip fractures, only in those who present with an unexplained fall and report a history of syncope or unexplained falls in the past. The vasodepressor/mixed forms account for the majority of CSH responses in the group of unexplained fallers. [source] Adsorbing colloid flotation for removal of metal ions in waters from base metal minesENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 1 2002H. Sabti Adsorbing Colloid Flotation (ACF) has been shown in laboratory experiments to be effective for the removal of heavy metals (Zn, Cu, Cd and Pb) from dilute solutions. Sodium dodecyl sulphate (SDS) and sodium oleate (NaOl) were used as surfactants in single or mixed form, with Fe(OH)3 as a flocculant for colloid formation. These reagents worked best for zinc and copper ions for a feed concentration of 50 parts per million (ppm). The removal of lead improved significantly by the use of Fe(OH)3 and NaLS (Sodium lauryl sulphate), while the best removal of cadmium was achieved by the use of Al(OH)3 and HTMABr (hexadecyltrimethylammonium bromide). Flotation experiments were conducted with feed concentrations of 50 and 500 parts per billion (ppb) and 50 ppm (parts per million). The experimental results showed that the residual concentration of metal ions decreased significantly with the decrease in the feed concentration. This could be the effect of excessive (much more than stoichiometric ratio) amounts of surfactant and flocculant, compared to the feed concentrations, required in the effective flotation of dilute feed solutions. The surfactant concentration and feed pH had the largest effects on the process, as observed in the case of cadmium removal. This can be attributed to the flocformation and flotation tendencies of the colloid-metal complexes at various solution pH and surfactant concentrations. The ACF method was applied to a number of natural drainage solutions from the metal mines at Te Aroha, New Zealand, and the experimental results demonstrate that significant removal is achieved for most of the heavy metals. [source] An a posteriori error estimator for the mimetic finite difference approximation of elliptic problemsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 11 2008Lourenço Beirão da Veiga Abstract We present an a posteriori error indicator for the mimetic finite difference approximation of elliptic problems in the mixed form. We show that this estimator is reliable and efficient with respect to an energy-type error comprising both flux and pressure. Its performance is investigated by numerically solving the diffusion equation on computational domains with different shapes, different permeability tensors, and different types of computational meshes. Copyright © 2008 John Wiley & Sons, Ltd. [source] Convergence of MPFA on triangulations and for Richards' equationINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 12 2008R. A. Klausen Abstract Spatial discretization of transport and transformation processes in porous media requires techniques that handle general geometry, discontinuous coefficients and are locally mass conservative. Multi-point flux approximation (MPFA) methods are such techniques, and we will here discuss some formulations on triangular grids with further application to the nonlinear Richards equation. The MPFA methods will be rewritten to mixed form to derive stability conditions and error estimates. Several MPFA versions will be shown, and the versions will be discussed with respect to convergence, symmetry and robustness when the grids are rough. It will be shown that the behavior may be quite different for challenging cases of skewness and roughness of the simulation grids. Further, we apply the MPFA discretization approach for the Richards equation and derive new error estimates without extra regularity requirements. The analysis will be accompanied by numerical results for grids that are relevant for practical simulation. Copyright © 2008 John Wiley & Sons, Ltd. [source] Psychotherapeutic case conceptualization using plan analysis for bipolar affective disorder,JOURNAL OF CLINICAL PSYCHOLOGY, Issue 4 2009Ueli Kramer Abstract Valid individualized case conceptualization methodologies, such as plan analysis, are rarely used for the psychotherapeutic treatment conceptualization and planning of bipolar affective disorder (BD), even if data do exist showing that psychotherapy interventions might be enhanced by applying such analyses for treatment planning for several groups of patients. We applied plan analysis as a research tool (Caspar, 1995) to N=30 inpatients presenting BD, who were interviewed twice. Our study aimed at producing a prototypical plan structure encompassing the most relevant data from the 30 individual case conceptualizations. Special focus was given to links with emotions and coping plans. Inter-rater reliability of these plan analyses was considered sufficient. Results suggest the presence of two subtypes based on plananalytic principles: emotion control and relationship control, along with a mixed form. These subtypes are discussed with regard to inherent plananalytic conflicts, specific emotions and coping plans, as well as symptom level and type. Finally, conclusions are drawn for enhancing psychotherapeutic practice with BD patients, based on the motive-oriented therapeutic relationship. © 2009 Wiley Periodicals, Inc. J Clin Psychol 65: 1,16, 2009. [source] A FEM,DtN formulation for a non-linear exterior problem in incompressible elasticityMATHEMATICAL METHODS IN THE APPLIED SCIENCES, Issue 2 2003Gabriel N. Gatica Abstract In this paper, we combine the usual finite element method with a Dirichlet-to-Neumann (DtN) mapping, derived in terms of an infinite Fourier series, to study the solvability and Galerkin approximations of an exterior transmission problem arising in non-linear incompressible 2d-elasticity. We show that the variational formulation can be written in a Stokes-type mixed form with a linear constraint and a non-linear main operator. Then, we provide the uniqueness of solution for the continuous and discrete formulations, and derive a Cea-type estimate for the associated error. In particular, our error analysis considers the practical case in which the DtN mapping is approximated by the corresponding finite Fourier series. Finally, a reliable a posteriori error estimate, well suited for adaptive computations, is also given. Copyright © 2003 John Wiley & Sons, Ltd. [source] Preconditioners for the discretized time-harmonic Maxwell equations in mixed formNUMERICAL LINEAR ALGEBRA WITH APPLICATIONS, Issue 4 2007Chen Greif Abstract We introduce a new preconditioning technique for iteratively solving linear systems arising from finite element discretization of the mixed formulation of the time-harmonic Maxwell equations. The preconditioners are motivated by spectral equivalence properties of the discrete operators, but are augmentation free and Schur complement free. We provide a complete spectral analysis, and show that the eigenvalues of the preconditioned saddle point matrix are strongly clustered. The analytical observations are accompanied by numerical results that demonstrate the scalability of the proposed approach. Copyright © 2007 John Wiley & Sons, Ltd. [source] Multiscale methods for elliptic homogenization problems,NUMERICAL METHODS FOR PARTIAL DIFFERENTIAL EQUATIONS, Issue 2 2006Zhangxin ChenArticle first published online: 10 JUN 200 Abstract In this article we study two families of multiscale methods for numerically solving elliptic homogenization problems. The recently developed multiscale finite element method [Hou and Wu, J Comp Phys 134 (1997), 169,189] captures the effect of microscales on macroscales through modification of finite element basis functions. Here we reformulate this method that captures the same effect through modification of bilinear forms in the finite element formulation. This new formulation is a general approach that can handle a large variety of differential problems and numerical methods. It can be easily extended to nonlinear problems and mixed finite element methods, for example. The latter extension is carried out in this article. The recently introduced heterogeneous multiscale method [Engquist and Engquist, Comm Math Sci 1 (2003), 87,132] is designed for efficient numerical solution of problems with multiscales and multiphysics. In the second part of this article, we study this method in mixed form (we call it the mixed heterogeneous multiscale method). We present a detailed analysis for stability and convergence of this new method. Estimates are obtained for the error between the homogenized and numerical multiscale solutions. Strategies for retrieving the microstructural information from the numerical solution are provided and analyzed. Relationship between the multiscale finite element and heterogeneous multiscale methods is discussed. © 2005 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2006 [source] Nocturia: An austrian study on the multifactorial etiology of this symptom,,NEUROUROLOGY AND URODYNAMICS, Issue 5 2009H. Christoph Klingler Abstract Aims To identify the different factors contributing to nocturia in a clinical setting. Patients and Methods Three hundred twenty-four patients (133 women, 191 men; mean age 63 years) were entered into this multi-institutional study. When presenting with nocturia we obtained detailed medical history and performed urine analysis, post-void residual volume and renal ultrasonography. Bothersome score and quality of life were evaluated using visual analogue scale and Kings' Health Questionnaire (KHQ), respectively. Patients were asked to complete a 48-hr voiding diary (VD). Nocturia and its associated problems were evaluated using KHQ and VD in conjunction with concurrent health variables. Results Mean nocturia was 2.8 in men versus in 3.1 women. Fifty percent of patients were aged >65 years, 60% had daytime lower urinary tract symptoms (LUTS) as well as nocturia, 33% had cardiac pathologies and 7% had peripheral edema. Principal causes for nocturia were global polyuria in 17%, nocturnal polyuria (NP) in 33% and reduced functional capacity <250 ml in 16.2%; 21.2% had mixed forms of NP and reduced bladder capacity and 12.6% suffered from other causes. Mean bothersome score was higher in women (P,<,0.001) and in patients with NP (P,=,0.012). Quality of life was significantly lower in women (P,=,0.001), in patients aged >65 years (P,=,0.029) and in those with reduced functional capacity (P,<,0.001). Mean voided 24-hr urine was higher in women (P,=,0.033) and in patients aged <65 years (P,=,0.019). Conclusions Nocturia had a high impact on bothersome score, strong associations with poor health and other LUTS. NP was the predominant cause of nocturia. Neurourol. Urodynam. 28:427,431, 2009. © 2009 Wiley-Liss, Inc. [source] | ||||||||||||||||