A Plane Wave Virtual Element Method for the Helmholtz Problem

We introduce and analyze a virtual element method (VEM) for the Helmholtz problem with approximating spaces made of products of low order VEM functions and plane waves. We restrict ourselves to the 2D Helmholtz equation with impedance boundary conditions on the whole domain boundary. The main ingredients of the plane wave VEM scheme are: i) a low frequency space made of VEM functions, whose basis functions are not explicitly computed in the element interiors; ii) a proper local projection operator onto the high-frequency space, made of plane waves; iii) an approximate stabilization term. A convergence result for the h-version of the method is proved, and numerical results testing its performance on general polygonal meshes are presented

Exponentially Fitted Discontinuous Galerkin Schemes for Singularly Perturbed Problems

New discontinuous Galerkin schemes in mixed form are introduced for symmetric elliptic problems of second order. They exhibit reduced connectivity with respect to the standard ones. The modifications in the choice of the approximation spaces and in the stabilization term do not spoil the error estimates. These methods are then used for designing new exponentially fitted schemes for advection dominated equations. The presented numerical tests show the good performances of the proposed schemes.Fil: Lombardi, Ariel Luis. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Matemática; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pietra, Paola. Consiglio Nazionale delle Ricerche. Istituto di Matematica Applicata e Tecnologie Informatiche; Itali

Comparison of Enhanced Organic Rankine Cycles for Geothermal Power Units

Binary cycles have drawn the attention as a technical solution for the geothermal power production. This attention is mainly due to the huge potential of medium-low temperature geothermal sources, typically exploited by means of a binary cycle, and the relevance of the environmental concern, which can be conveniently dealt with by means of a closed cycle. The binary cycle has been therefore the object of an extended research activity, in order to attain higher plant performance. A crucial matter is the improvement of the heat introduction process. For a given geothermal fluid in liquid state, i.e. for a variable temperature heat source, in a conventional ORC the working fluid evaporation process is responsible for an important second law loss: removal of this loss allows greater power and possibly higher cycle efficiency to be attained. Aim of the present paper is to investigate and compare recently proposed technical solutions based on the current technology, which do not entail considerable operating risk or relevant investment; they can however lead to an improvement in plant performance and economics. The selected cycle options were dealt with in the open literature, and try to reduce the heat introduction second law loss: in the first one, the so called OFC, this loss is strongly reduced, because heat is introduced in the cycle when the working fluid is in liquid phase, but a dissipative flash process is then required. In the second one, the so called Pinch Point Smoother, this loss is reduced because the working fluid heating curve is smoothed by means of a flow split, which allows a fraction of the working fluid flow to evaporate at a pressure lower than the pressure of the main flow, but mechanical recompression is then required to inject the separated flow fraction into the turbine. The result of comparison may depend both on the temperature level of thermal sources involved and on the working fluid selected: the present paper will discuss several examples, representative of geothermal applications, and try to assess whether the adoption of these solutions can be convenient for geothermal exploitation

A Quantum Drift-Diffusion model and its use into a hybrid strategy for strongly confined nanostructures

International audienceIn this paper we derive by an entropy minimization technique a local Quantum Drift-Diffusion (QDD) model that allows to describe with accuracy the transport of electrons in confined nanostructures. The starting point is an effective mass model, obtained by considering the crystal lattice as periodic only in the one dimensional longitudinal direction and keeping an atomistic description of the entire two dimensional cross-section. It consists of a sequence of one dimensional device dependent Schrödinger equations, one for each energy band, in which quantities retaining the effects of the confinement and of the transversal crystal structure are inserted. These quantities are incorporating into the definition of the entropy and consequently the QDD model that we obtain has a peculiar quantum correction that includes the contributions of the different energy bands. Next, in order to simulate the electron transport in a gate-all-around Carbon Nanotube Field Effect Transistor, we propose a spatial hybrid strategy coupling the QDD model in the Source/Drain regions and the Schrödinger equations in the channel. Self-consistent computations are performed coupling the hybrid transport equations with the resolution of a Poisson equation in the whole three dimensional domain

An LC-MS/MS method for the determination of budesonide and 16α-hydroxyprednisolone in dog plasma

open6noAlthough budesonide is frequently used in veterinary medicine for the treatment of canine respiratory and bowel inflammatory diseases, knowledge is lacking regarding its kinetics in this species. We developed and validated a liquid chromatography–tandem mass spectrometry method for the determination of budesonide and its metabolite 16a-hydroxyprednisolone in dog plasma. The analytes were extracted by solid phase extraction and analysis was performed by high performance liquid chromatography–tandem mass spectrometry, with positive electrospray ionization. This method allows budesonide and one of its main metabolites to be simultaneously quantified in dog plasma at fairly low concentrations. The proposed protocol is very easy and fast to execute, without compromising analytical performances. A small amount (0.5mL) of plasma is required, making this approach suitable for pharmacokinetic studies also in small sized dogs.openGazzotti, Teresa; Barbarossa, Andrea; Zironi, Elisa; Roncada, Paola; Pietra, Marco; Pagliuca, GiampieroGazzotti, Teresa; Barbarossa, Andrea; Zironi, Elisa; Roncada, Paola; Pietra, Marco; Pagliuca, Giampier

Targeting Syndecan-1, a molecule implicated in the process of vasculogenic mimicry, enhances the therapeutic efficacy of the L19-IL2 immunocytokine in human melanoma xenografts

Anti-angiogenic therapy of solid tumors has until now failed to produce the long lasting clinical benefits desired, possibly due to the complexity of the neoangiogenic process. Indeed, a prominent role is played by "vasculogenic" or "vascular" mimicry (VM), a phenomenon in which aggressive cancer cells form an alternative microvascular circulation, independently of endothelial cell angiogenesis. In this study we observed, in melanoma patient cell lines having vasculogenic/stem-cell like phenotype and in melanoma tumors, the syndecan-1 co-expression with VM markers, such as CD144 and VEGFR-2. We show that melanoma cells lose their ability to form tubule-like structures in vitro after blocking syndecan-1 activity by the specific human recombinant antibody, OC-46F2. Moreover, in a human melanoma xenograft model, the combined therapy using OC-46F2 and L19-IL2, an immunocytokine specific for the tumor angiogenic-associated B-fibronectin isoform(B-FN), led to a complete inhibition of tumor growth until day 90 from tumor implantation in 71% of treated mice, with statistically significant differences compared to groups treated with OC-46F2 or L19-IL2 as monotherapy. Furthermore, in the tumors recovered from mice treated with OC-46F2 either as monotherapy or in combination with L19-IL2, we observed a dramatic decrease of vascular density and loss of VM structures. These findings indicate for the first time a role of syndecan-1 in melanoma VM and that targeting syndecan-1, together with B-FN, could be promising in improving the treatment of metastatic melanoma

Evaluation of clinicopathological features in cats with chronic gastrointestinal signs

Food-responsive enteropathy (FRE), idiopathic inflammatory bowel disease (IBD), and alimentary tract lymphoma (AL) are often the remaining differentials for cats presenting with chronic gastrointestinal (GI) signs. Differential diagnosis is further complicated by overlapping clinicopathological features and histopathological changes, however. In this study we describe the clinical presentation of cats with chronic GI signs secondary to FRE, IBD, and AL, and evaluate possible associations between clinical, clinicopathological, ultrasonographic findings and diagnosis. The medical records of client-owned cats with chronic GI signs secondary to FRE, IBD, and AL were reviewed. Univariate and multivariate logistic regression models and receiver-operating characteristic curve (ROC) analysis were used for testing the data. Of the 56 cats included in the study, 22 were diagnosed with FRE (mean age, 70 months ± 49), 17 with IBD (mean age, 101 months ± 40), and 17 with AL (mean age, 122 months ± 45). Cats with FRE were younger and presented more often with diarrhea and less frequently with muscle wasting than cats with IBD or AL. In cats with AL, serum cobalamin levels were lower than in those with FRE or IBD (239 ± 190 ng/L vs. 762 ± 408 ng/L and 625 ± 443 ng/L, respectively) and folate levels were higher than in cats with IBD (18.2 ± 4.2 μg/L vs. 9.1 ± 4.7 μg/L, respectively). Multivariate/ROC curve analysis showed increased values of BUN (sensitivity 100, specificity 29.4, criterion >37 mg/dl) and serum folate (sensitivity 80, specificity 100, criterion >15.6 μg/L) and reduced values of cobalamin (sensitivity 100, specificity 62.5, criterion â¤540 ng/L), which suggested a diagnosis of AL versus IBD. Some clinicopathological features evaluated at diagnosis might suggest AL; however, because differentiating AL from IBD is often difficult, definitive diagnosis should be based on invasive diagnostic workup

A Block Solver for the Exponentially Fitted IIPG-0 method

We consider an exponentially fitted discontinuous Galerkin method and propose a robust block solver for the resulting linear systems.Comment: 8 pages, 2 figures, 2 table

ATUAÇÃO CONTEMPORÂNEA E O CINEMA DE GARAGEM: CORPOS DE INFERNINHO NAS BORDAS DO FICCIONAL

Propomos neste artigo uma discussão que leva em consideração as contaminações entre teatro e cinema, com um olhar voltado à atuação, ao acontecimento e ao processo criativo que desloca a ênfase da autoria única para praticar um tipo de composição que se dá no plural. Para isso, investigamos essas relações a partir do contexto de realização do filme Inferninho (2018, Ceará – Brasil), trabalho resultante da amizade e encantamento entre o coletivo de cinema Alumbramento e o Grupo Bagaceira de Teatro. A proposta reflexiva partiu de mapeamento conceitual a fim de levantar questionamentos sobre a atuação contemporânea; de nossa percepção como espectadoras e espectador do filme em questão; além de entrevista com a equipe de produção. Consideramos as noções de cinema de garagem e brodagem (Marcelo Ikeda), amizade e contemporâneo (Giorgio Agamben) como estímulos para a discussão

Paralelización del modelo Híbrido Clásico-Cuántico para un Dispositivo Semiconductor Mosfet Nanométrico

The expensive reengineering of the sequential software and the difficult parallel programming are two of the many technical and economic obstacles to the wide use of HPC. We investigate the chance to improve in a rapid way the performance of a numerical serial code for the simulation of the transport of a charged carriers in a Double-Gate MOSFET. We introduce the Drift-Diffusion-Schrödinger-Poisson (DDSP) model and we study a rapid parallelization strategy of the numerical procedure on shared memory architectures.El transformar un software secuencial en uno paralelo, es costoso y difícil, lo cual constituye solo dos de los muchos obstáculos técnicos y económicos que se tienen que enfrentar cuando se desea hacer uso de sistemas HPC. En este trabajo investigamos la posibilidad de mejorar de forma rápida y eficiente el desempeño de un código numérico secuencial que se encarga de realizar la simulación del comportamiento y transporte de un flujo de electrones en un dispositivo semiconductor MOSFET doble puerta y de escala nanométrico. Se  introduce el modelo Drift-Diffusion- Schrödinger-Poisson (DDSP) y se estudia una estrategia de paralelización rápida del procedimiento numérico, óptimo específicamente para arquitecturas a memoria compartida