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Scientific applications face the challenge of efficiently exploiting increasingly complex parallel and distributed systems. Developing hand-tuned codes is a time-consuming, tedious and hardly reusable task. Reaching high performance appears detrimental to productivity and portability and unreasonable to expect from scientists. Domain-Specific Languages (DSLs) are collaborative environments aiming to overcome such difficulties by decoupling the problem description from the algorithmic implementation. However, developing a competitive tool in High-Performance Computing (HPC) is challenging: DSLs for HPC environments have two additional critical requirements, performance and scalability. Moreover, documented and successful cases are few, making it difficult to popularise DSLs as problem-solving environments for scientific HPC code development. In this context, Saiph is a task-based DSL easing the simulation of physical phenomena from Computational Fluid Dynamics (CFD), developed to meet HPC productivity and performance requirements. This work reports the tuning and evaluation of Saiph using the Taylor–Green Vortex (TGV) problem as a case study. We assess Saiph’s productivity, numerical methods, and high-performance strategies to illustrate its use and demonstrate its competitiveness, viability and benefits for CFD software developments in HPC environments. Hence, we contribute to the popularisation of HPC DSLs as suitable problem-solving environments able to unify modern computational and scientific knowledge., This work has been supported by the Generalitat de Catalunya (contract 2021-SGR-01007), the Spanish Ministry of Science and Technology (contract PID2019-107255 GB), and Severo Ochoa (CEX2021- 001148-S/MCIN/AEI/10.13039/ 501100011033)., Peer Reviewed, Postprint (author's final draft)

Myelin Water Imaging has become an important, while challenging tool in magnetic resonance imaging for visualizing the myelination state of white matter in vivo. Different neurodegenerative diseases, such as multiple sclerosis (MS) or schizophrenia can be linked with a reduction of myelin water fraction (MWF). However, a low signal-to-noise ratio can decrease the quality of MWF maps, which makes noise reduction a crucial step in the pre-processing pipeline. Our goal was to demonstrate the performance of noise reduction using Total generalized variation (TGV) filtering compared to conventional filters, such as Gaussian and Wiener filtering. Here, we aquired accelerated 3D gradient and spin echo (GRASE) images of four subjects with a voxel size of 2.95 mm³ and one subject with 3.95 mm³ voxel size. In all subjects, distinct regions of interest (ROI) were defined in the brain tissue, including five bilateral white matter (WM) structures and whole WM slices. Our results showed significant enhanced fit-to-noise ratio (FNR) values of multi-echo GRASE images filtered with TGV, Gaussian and Wiener algorithms compared to unfiltered. Variability of MWF values in WM ROIs were decreased after filtering with all three methods, while mean MWF values were unchanged between unfiltered and filtered images. FNR and MWF measurements of all subjects demonstrated that pre-filtering the data could result in myelin water maps with improved quality and better definition of small image structures. Finally, noise reduction and thus more reliable myelin water maps can lead to certain advantages in the field of multiple sclerosis.*****Myelin Water Imaging has become an important, while challenging tool in magnetic resonance imaging for visualizing the myelination state of white matter in vivo. Different neurodegenerative diseases, such as multiple sclerosis (MS) or schizophrenia can be linked with a reduction of myelin water fraction (MWF). However, a low signal-to-noise ratio can decrease the

Povećanje konkuretnosti železničkih transportnih sistema u odnosu na druge vidove transportnih sistema u poslednjih šezdeset godina rezultat je intenzivnog razvoja novih generacija brzih vozova. Ove vrste vozova ne samo da zadovoljavaju potrebe za povećanom brzinom prevoza, a tako i kraće vreme putovanja, već i zahteve za povećanje pouzdanosti, sigurnosti i direktne primene energetske efikasnosti na sam sistem transporta. Sa povećanjem brzine vozova, povećavaju se i otpori kretanja, pri čemu pri brzinama većim od 200 km/h udeo otpora vazduha postaje najdominantniji član. Jedna od najefikasnijih mera za smanjenje otpora vazduha, kao i ostalih negativnih posledica koje nastaju pri kretanju velikim brzinama, je razvoj aerodinamičkog oblika voza. U ovom radu su predstavljena neka od konstrukcionih rešenja koja utiču na aerodinamičke karakteristike vozova velikih brzina, pre svega oblik čeonog dela, kao i sličnosti i razlike pojedinih podsistema neophodnih za funkcionisanje savremenih železničkih sisteme vozova velikih brzina. Analizirana su dva pristupa rešavanja problema aerodinamičkog oblika voza i odgovarajuće infrastructure na primeru Japana i Francuske. Razmatrana su dva modela voza velikih brzina, Shinkansen (Japan) i TGV odnosno AGV (Francuska.)., Increased advantages of railway transportation systems over other types of transportation systems in the past sixty years have been a result of an intensive development of the new generations of high-speed trains. Not only do these types of trains comply with the need for increased speed of transportation and make the duration of the journey shorter, but they also meet the demands for increased reliability, safety and direct application of energy efficiency to the transportation system itself. Along with increased train speed, the motion resistance is increased as well, whereby at speeds over 200 km/h the proportion of air resistance becomes the most dominant member. One of the most efficient measures for reducing air resistance, as well as other negative consequences of high-speed motion, is the development of the aerodynamic shape of the train. This paper presents some construction solutions that affect the aerodynamic properties of high-speed trains, first and foremost, the nose shape, as well as the similarities and differences of individual subsystems necessary for the functioning of modern high-speed rail systems. We analysed two approaches to solving the problem of the aerodynamic shape of the train and the appropriate infrastructure using the examples of Japan and France. Two models of high-speed trains, Shinkansen (Japan) and TGV, i.e. AGV (France), have been discussed.

El estudio del flujo pulsante es de vital importancia para esclarecer el efecto que tiene sobre el rendimiento de una turbina, además de permitir desarrollar técnicas que permiten aprovechar la energía contenida en los pulsos como el concepto de control activo. También se ha desarrollado un método de extrapolación de mapas de turbinas.

El estudio del flujo pulsante es de vital importancia para esclarecer el efecto que tiene sobre el rendimiento de una turbina, además de permitir desarrollar técnicas que permiten aprovechar la energía contenida en los pulsos como el concepto de control activo. También se ha desarrollado un método de extrapolación de mapas de turbinas.

El estudio del flujo pulsante es de vital importancia para esclarecer el efecto que tiene sobre el rendimiento de una turbina, además de permitir desarrollar técnicas que permiten aprovechar la energía contenida en los pulsos como el concepto de control activo. También se ha desarrollado un método de extrapolación de mapas de turbinas.

El estudio del flujo pulsante es de vital importancia para esclarecer el efecto que tiene sobre el rendimiento de una turbina, además de permitir desarrollar técnicas que permiten aprovechar la energía contenida en los pulsos como el concepto de control activo. También se ha desarrollado un método de extrapolación de mapas de turbinas.

La présente étude évalue l’impact de l’implantation d’un train à grande vitesse (TGV) sur la croissance de l’emploi, dans le corridor Québec-Windsor. Pour ce faire, nous utilisons un modèle économétrique qui considère l’accessibilité aux marchés nord-américains. La croissance de l’emploi est évaluée sur la période du dernier recensement (2001-2006) et répartie en 413 unités spatiales pour tout le Canada. Les deux trajets à l’étude s’étendent de la ville de Québec à la ville de Windsor. Le premier trajet passe sur la rive nord du fleuve et compte peu d’arrêts dans les villes intermédiaires. Le deuxième traverse les régions plus urbanisées de la rive sud et s’arrête dans plusieurs villes moyennes. L’étude se divise en trois étapes. La première consiste à calculer les variables d’accessibilité avec le logiciel ArcGIS afin de prendre en considération l’augmentation du niveau d’accessibilité due au TGV. Ensuite, la variable d’accessibilité sans TGV est intégrée à un modèle de régression multiple de façon à déterminer quelle est sa contribution réelle à la croissance de l’emploi. Dans la dernière étape, nous utilisons les variables d’accessibilité et le coefficient de régression pour estimer l’impact du TGV sur la croissance de l’emploi. Les résultats obtenus démontrent que le coefficient de régression pour l’accessibilité est de 1,8 %, et qu’il est statistiquement significatif. Pour chaque augmentation d’un écart type d’accessibilité, l’emploi connaît une croissance supplémentaire de 1,8 %. Notre analyse des résultats nous permet de constater que l’impact du TGV est concentré dans les villes qui possèdent une gare. La plus forte croissance d’emplois se retrouve dans les plus grandes agglomérations. Le nombre d’emplois créés est relativement faible pour le reste du corridor et nul pour les autres unités spatiales canadiennes. Le nombre d’emplois créés pour chaque trajet est d’environ 24 000 pour la rive nord et de 22 000 pour la rive sud. Finalement, le TGV devrait aussi

Se han considerado diferentes trazados del futuro AVE Madrid-Lisboa por Extremadura. A tenor de los diferentes criterios cualitativos escogidos (población servida directa por el AVE, distancias, nº de paradas, coste de las obras, impacto ambiental, intermodalidad y transporte de mercancías) se han tratado de hallar los trazados más adecuados de cara a optimizar los efectos positivos de desarrollo y progreso que una infraestructura de este tipo produciría a nivel territorial en Extremadura. Efectos que, por otra parte, se conocen mejor gracias a la década de experiencia que se ha obtenido en ciudades como Ciudad Real y Puertollano, muy semejantes en la mayoría de los aspectos a las extremeñas (Cáceres, Mérida, Badajoz,...). Algunos de los criterios descritos anteriormente (ser la zona de mayor población de Extremadura, tener trazados por relieves más suaves, tener menor impacto ambiental o mayor intermodalidad), determinan que los trazados que discurren por Mérida y Badajoz crean mayor vertebración de la región y tienen unas consecuencias mucho más favorables que otros, donde el trazado no conecta en altas prestaciones las tres ciudades más importantes de Extremadura: Cáceres, Mérida y Badajoz (denominados en la tesina Centro CMB-1,2 y Sur-S).