Efficient solvers for hybridized three-field mixed finite element coupled poromechanics

We consider a mixed hybrid finite element formulation for coupled poromechanics. A stabilization strategy based on a macro-element approach is advanced to eliminate the spurious pressure modes appearing in undrained/incompressible conditions. The efficient solution of the stabilized mixed hybrid block system is addressed by developing a class of block triangular preconditioners based on a Schur-complement approximation strategy. Robustness, computational efficiency and scalability of the proposed approach are theoretically discussed and tested using challenging benchmark problems on massively parallel architectures

Parallel Matrix-free polynomial preconditioners with application to flow simulations in discrete fracture networks

We develop a robust matrix-free, communication avoiding parallel, high-degree polynomial preconditioner for the Conjugate Gradient method for large and sparse symmetric positive definite linear systems. We discuss the selection of a scaling parameter aimed at avoiding unwanted clustering of eigenvalues of the preconditioned matrices at the extrema of the spectrum. We use this preconditioned framework to solve a $3 \times 3$ block system arising in the simulation of fluid flow in large-size discrete fractured networks. We apply our polynomial preconditioner to a suitable Schur complement related with this system, which can not be explicitly computed because of its size and density. Numerical results confirm the excellent properties of the proposed preconditioner up to very high polynomial degrees. The parallel implementation achieves satisfactory scalability by taking advantage from the reduced number of scalar products and hence of global communications

Avaliação de genótipos de feijoeiro comum dos grupos carioca e preto na região Sudoeste de Mato Grosso.

O objetivo desse trabalho é obter cultivares mais apropriadas para a agricultura familiar com uso da irrigação no feijoeiro, atendendo também outras regiões do Estado com características climáticas similares

Avaliação de genótipos de feijoeiro comum dos grupos carioca e preto na região Oeste de Mato Grosso.

O objetivo desse trabalho é obter cultivares mais tolerantes a altas temperaturas, menores altitudes e apropriadas para a agricultura familiar que atendam essas condições no estado de Mato Grosso

Modelling ground rupture due to groundwater withdrawal: applications to test cases in China and Mexico

Abstract. The stress variation induced by aquifer overdraft in sedimentary basins with shallow bedrock may cause rupture in the form of pre-existing fault activation or earth fissure generation. The process is causing major detrimental effects on a many areas in China and Mexico. Ruptures yield discontinuity in both displacement and stress field that classic continuous finite element (FE) models cannot address. Interface finite elements (IE), typically used in contact mechanics, may be of great help and are implemented herein to simulate the fault geomechanical behaviour. Two main approaches, i.e. Penalty and Lagrangian, are developed to enforce the contact condition on the element interface. The incorporation of IE incorporation into a three-dimensional (3-D) FE geomechanical simulator shows that the Lagrangian approach is numerically more robust and stable than the Penalty, thus providing more reliable solutions. Furthermore, the use of a Newton-Raphson scheme to deal with the non-linear elasto-plastic fault behaviour allows for quadratic convergence. The FE – IE model is applied to investigate the likely ground rupture in realistic 3-D geologic settings. The case studies are representative of the City of Wuxi in the Jiangsu Province (China), and of the City of Queretaro, Mexico, where significant land subsidence has been accompanied by the generation of several earth fissures jeopardizing the stability and integrity of the overland structures and infrastructure.</p

Paraneoplastic Anti-Tif1-gamma Autoantibody-positive Dermatomyositis as Clinical Presentation of Hepatocellular Carcinoma Recurrence

Hepatocellular carcinoma (HCC) is rarely associated with autoimmune paraneoplastic syndromes. We report a case of anti-transcriptional intermediary factor-1 gamma (TIF1-??)-positive dermatomyositis (DM) as clinical presentation of HCC recurrence in a 72-year-old male patient admitted to our hospital due to fatigue, myalgia, and typical skin rash. His medical history was notable for hepatitis C-related cir-rhosis, successful treatment with direct-acting antiviral agents, and previously efficacious treatment of HCC. Labo-ratory testing showed significant rhabdomyolysis with anti-TIF1-?? antibodies at high titer, and DM was diagnosed. After a careful diagnostic workup, HCC recurrence was diagnosed. After first-line corticosteroid treatment, azathioprine and in-travenous immunoglobulin treatments were administered; unfortunately, he mounted only partial response. Owing to the compromised performance status, no HCC treatment was feasible, and, according to international guidelines, he received only best supportive care. Here, we discuss the diagnostic, prognostic, and pathogenic roles of anti-TIF1-?? antibodies associated with paraneoplastic DM and the scant literature data on its occurrence in HCC patients. Consider-ing the TIF1 gene family???s established role in oncogenesis, we also review the role of TIF1-?? as a tumor-related neo-antigen, leading to the development of clinically overt anti-TIF1-?? antibodies-positive DM

Decompensated cirrhosis as presentation of LKM1/LC1 positive type 2 autoimmune hepatitis in adulthood. A rare clinical entity of difficult management

Background: Autoimmune hepatitis (AIH) is a chronic and aggressive liver disease that rapidly evolves into cirrhosis and end-stage liver disease if not timely diagnosed and treated with immunosuppressive therapy. AIH is classified into type 1 and type 2 according to the autoantibody pattern, with smooth muscle antibodies and/or antinuclear antibodies as serological markers of AIH-1, while antiliver cytosol antibody type 1 and/or antiliver/kidney microsomal antibody type 1 characterize type 2 AIH, which mainly affects children, including infants, and adolescents. Case Summary: We describe a case of type 2 AIH, clinically onset in a 34-year-old woman with decompensated cirrhosis. Only a thorough analysis of the autoantibody profile allowed for a diagnosis of an AIH-2 evolved into cirrhosis. The patient received a moderate corticosteroid therapy without achieving optimal disease control. We discuss the controversial decision of whether or not to treat the patient with immunosuppressive therapy, which should be balanced with the potential risk of infectious and other complications. A review of the literature on the management of patients with autoimmune cirrhosis is also presented. Conclusions: AIH-2 can be clinically onset in adult patients with cirrhosis and its complications, without being preceded by major clinical signs. Due to the difficult management of cirrhosis with immunosuppressive treatments, a patient-tailored strategy with a case-by-case approach is needed to prevent major complications such as infections, potentially precluding liver transplantation the only curative therapy

Upregulated Expression of Toll-like Receptor 4 in Peripheral Blood of Ischaemic Stroke Patients Correlates with Cyclooxygenase 2 Expression

AbstractObjectivesAn inflammatory process following stroke in human brains and systemic inflammatory responses after stroke in humans have been reported by numerous investigators. The aim of the study was to investigate if genes involved in the cyclooxygenase 2 (COX-2) pathway are upregulated at peripheral level in patients after transient ischaemic attack (TIA) and stroke.Design of StudyBlood samples were obtained from two groups of patients undergoing carotid endarterectomy. The first group included 25 patients who presented TIA or ischaemic stroke. The second group included 35 patients who had an asymptomatic internal carotid artery stenosis. Total RNA was isolated and the expression of Toll-like Receptor 4 (TLR4), COX-2, membrane-associated Prostaglandin E synthase (mPGES-1), Prostaglandin E2 receptors (EP3 and EP4) was analysed by real time RT-PCR.ResultsExpression of COX-2 and TLR4 were significantly increased in symptomatic patients (p<0.001). Correlation analysis showed that TLR4 expression significantly correlated with COX-2 expression (R=0.65; p<0.01) in ischaemic stroke patients. This correlation was not observed in TIA and asymptomatic patients.ConclusionsOur results suggest that the peripheral mechanism of inflammatory injury after stroke may be mediated by TLR4 through a COX-2-dependent pathway

Crescimento da batateira em sistema de preparo profundo de solo e sucessão de poáceas.

O presente estudo, realizado com a cultivar Atlantic, teve como objetivo comparar o sistema de preparo convencional (PC) de solo adotado para a cultura da batata, em sucessão à cultura do milho, a um sistema de preparo profundo (PP), em sucessão a três diferentes poáceas (milho, capim Marandu capim Tanzânia) quanto à dinâmica do crescimento da batateira. A produção em matéria seca (MS, t/ha) da parte aérea das poáceas variou conforme: Tanzânia PP (26,56) > Marandu PP (19,94) > Milho PP (5,57) = Milho PC (5,720)