Using graphics processors to accelerate the computation of the matrix inverse

We study the use of massively parallel architectures for computing a matrix inverse. Two different algorithms are reviewed, the traditional approach based on Gaussian elimination and the Gauss-Jordan elimination alternative, and several high performance implementations are presented and evaluated. The target architecture is a current general-purpose multi-core processor (CPU) connected to a graphics processor (GPU). Numerical experiments show the efficiency attained by the proposed implementations and how the computation of large-scale inverses, which only a few years ago would have required a distributed-memory cluster, take only a few minutes on a hybrid architecture formed by a multi-core CPU and a GPU

Observaciones con lámpara de hendidura: Reflexión especular y dispersión escleral

The slit lamp enables the user to inspect some eye segments by different illumination techniques. One of them, specular reflection, allow the user to evaluate the corneal endothelium. This work shows two photographs about different techniques: specular reflection is valuable for examining the corneal endothelium and scattering sclero-corneal illumination for studying the structure and transparency of the cornea. El biomiscroscopio o lámpara de hendidura permite la observación de las distintas estructuras que componen el globo ocular mediante diferentes técnicas de observación. En este trabajo se presentan dos técnicas distintas: la reflexión especular que permite la visualización de las células endoteliales y la dispersión escleral que permite la detección de opacidades corneales

Unleashing GPU acceleration for symmetric band linear algebra kernels and model reduction

Linear algebra operations arise in a myriad of scientific and engineering applications and, therefore, their optimization is targeted by a significant number of high performance computing (HPC) research efforts. In particular, the matrix multiplication and the solution of linear systems are two key problems with efficient implementations (or kernels) for a variety of high per- formance parallel architectures. For these specific prob- lems, leveraging the structure of the associated matrices often leads to remarkable time and memory savings, as is the case, e.g., for symmetric band problems. In this work, we exploit the ample hardware concurrency of many-core graphics processors (GPUs) to accelerate the solution of symmetric positive definite band linear systems, introducing highly tuned versions of the corre- sponding LAPACK routines. The experimental results with the new GPU kernels reveal important reductions of the execution time when compared with tuned imple- mentations of the same operations provided in Intel’s MKL. In addition, we evaluate the performance of the GPU kernels when applied to the solution of model or- der reduction problems and the associated matrix equa- tions.Ernesto Dufrechou and Pablo Ezzatti acknowledge the support from Programa de Desarrollo de las Ciencias Básicas, and Agencia Nacional de Investigación e Innovacioón, Uruguay. Enrique S. Quintana-Ortí was sup- ported by project TIN2011-23283 of the Ministry of Science and Competitiveness (MINECO) and EU FEDER, and project P1-1B2013-20 of the Fundació Caixa Castelló-Bancaixa and UJI

The Antioxidant Potential of the Mediterranean Diet in Patients at High Cardiovascular Risk: An In-Depth Review of the PREDIMED

Cardiovascular disease (CVD) is the leading global cause of death. Diet is known to be important in the prevention of CVD. The PREDIMED trial tested a relatively low-fat diet versus a high-fat Mediterranean diet (MedDiet) for the primary prevention of CVD. The resulting reduction of the CV composite outcome resulted in a paradigm shift in CV nutrition. Though many dietary factors likely contributed to this effect, this review focuses on the influence of the MedDiet on endogenous antioxidant systems and the effect of dietary polyphenols. Subgroup analysis of the PREDIMED trial revealed increased endogenous antioxidant and decreased pro-oxidant activity in the MedDiet groups. Moreover, higher polyphenol intake was associated with lower incidence of the primary outcome, overall mortality, blood pressure, inflammatory biomarkers, onset of new-onset type 2 diabetes mellitus (T2DM), and obesity. This suggests that polyphenols likely contributed to the lower incidence of the primary event in the MedDiet groups. In this article, we summarize the potential benefits of polyphenols found in the MedDiet, specifically the PREDIMED cohort. We also discuss the need for further research to confirm and expand the findings of the PREDIMED in a non-Mediterranean population and to determine the exact mechanisms of action of polyphenols

Solving Algebraic Riccati Equations on Hybrid CPU-GPU Platforms

The solution of Algebraic Riccati Equations is required in many linear optimal and robust control methods such as LQR, LQG, Kalman filter, and in model order reduction techniques like the balanced stochastic truncation method. Numerically reliable algorithms for these applications rely on the sign function method, and require O(8n3) floating-point arithmetic operations, with n in the range of 103 −105 for many practical applications. In this paper we investigate the use of graphics processors (GPUs) to accelerate the solution of Algebraic Riccati Equations by off-loading the computationally intensive kernels to this device. Experiments on a hybrid platform compose by state-of-the-art general-purpose multi-core processors and a GPU illustrate the potential of this approach.Sociedad Argentina de Informática e Investigación Operativ

Hyperspectral Unmixing on Multicore DSPs: Trading Off Performance for Energy

Wider coverage of observation missions will increase onboard power restrictions while, at the same time, pose higher demands from the perspective of processing time, thus asking for the exploration of novel high-performance and low-power processing architectures. In this paper, we analyze the acceleration of spectral unmixing, a key technique to process hyperspectral images, on multicore architectures. To meet onboard processing restrictions, we employ a low-power Digital Signal Processor (DSP), comparing processing time and energy consumption with those of a representative set of commodity architectures. We demonstrate that DSPs offer a fair balance between ease of programming, performance, and energy consumption, resulting in a highly appealing platform to meet the restrictions of current missions if onboard processing is required

Toward Light-Controlled Supramolecular Peptide Dimerization

The selective photodeprotection of the NVoc-modified FGG tripeptide yields the transformation of its 1:1 receptor−ligand complex with cucurbit[8]uril into a homoternary FGG2@CB8 assembly. The resulting lightinduced dimerization of the model peptide provides a tool for the implementation of stimuli-responsive supramolecular chemistry in biologically relevant contexts.The work was supported by the Associate Laboratory for Green ChemistryLAQV (UIDB/50006/2020) and by the Applied Molecular Biosciences UnitUCIBIO (UIDB/ 04378/2020), both financed by FCT. FCT/MCTES is also acknowledged for supporting the National Portuguese NMR Network (ROTEIRO/0031/2013-PINFRA/22161/2016, cofinanced by FEDER through COMPETE 2020, POCI, PORL, and FCT through PIDDAC) and for the grants PTDC/QUICOL/32351/2017, PTDC/QUI-QFI/30951/2017, and CEECIND/00466/2017 (N.B.). U.P. thanks the Spanish Ministry of Science, Innovation, and Universities (CTQ2017-89832-P). We are grateful to Dr. J.P. Da Silva for the mass spectrometry data (equipment financed by CRESC Algarve 2020 and COMPETE 2020; project EMBRC.PT ALG-01-0145-FEDER022121). Funding for open access charge: Universidad de Huelva / CBU

Dual role of copper on the reactivity of activated carbons from coal and lignocellulosic precursors

The synthesis of copper-doped activated carbons from different origin (i.e., lignocellulosic and bituminous coal) by a wet impregnation and low temperature calcination procedure has been explored, as well as the role of copper particles on the physicochemical and structural features of the resulting materials. The textural characterization and isothermal reactivity analysis of the pristine and doped activated carbons have shown that the role of copper during the calcination step strongly depended on the nature of the carbon matrix. Copper impregnation of a coal-derived activated carbon catalyzed the air gasification of the material at a very low temperature (i.e., 325 °C), bringing about the development of microporosity on the doped carbon. In contrast, when copper was immobilized on a lignocellulose-derived activated carbon, the metallic species act as combustion retardant during the calcination step, protecting the carbon matrix during the catalytic gasification. In both cases, the resulting materials displayed a homogenous distribution of copper within the carbon matrix, while preserving large textural properties.The authors thank the Spanish MICINN for financial support (projects CTM2008-01956/TECNO and Acción Integrada AIB2010PT-00209). MH thanks CSIC for a postdoctoral contract. MA thanks FCT for her PhD fellowship (SFRH/BD/71673/2010). The authors also thank Cordex for kindly providing the sisal residues.Peer reviewe

The Impact of the Multi-core Revolution on Signal Processing

This paper analyzes the influence of new multi- core and many-core architectures on Signal Processing. The article covers both the architectural design and the programming models of current general-purpose multi-core processors and graphics processors (GPU), with the goal of identifying their possibilities and impact on signal processing applications

Tuning the selectivity of natural oils and fatty acids/esters deoxygenation to biofuels and fatty alcohols : A review

The chemical transformation of natural oils provides alternatives to limited fossil fuels and produces compounds with added value for the chemical industries. The selective deoxygenation of natural oils to diesel-ranged hydrocarbons, bio-jet fuels, or fatty alcohols with controllable selectivity is especially attractive in natural oil feedstock biorefineries. This review presents recent progress in catalytic deoxygenation of natural oils or related model compounds (e.g., fatty acids) to renewable liquid fuels (green diesel and bio-jet fuels) and valuable fatty alcohols (unsaturated and saturated fatty alcohols). Besides, it discusses and compares the existing and potential strategies to control the product selectivity over heterogeneous catalysts. Most research conducted and reviewed has only addressed the production of one category; therefore, a new integrative vision exploring how to direct the process toward fuel and/or chemicals is urgently needed. Thus, work conducted to date addressing the development of new catalysts and studying the influence of the reaction parameters (e.g., temperature, time and hydrogen pressure) is summarized and critically discussed from a green and sustainable perspective using efficiency indicators (e.g., yields, selectivity, turnover frequencies and catalysts lifetime). Special attention has been given to the chemical transformations occurring to identify key descriptors to tune the selectivity toward target products by manipulating the reaction conditions and the structures of the catalysts. Finally, the challenges and future research goals to develop novel and holistic natural oil biorefineries are proposed. As a result, this critical review provides the readership with appropriate information to selectively control the transformation of natural oils into either biofuels and/or value-added chemicals. This new flexible vision can help pave the wave to suit the present and future market needs