The Dynamical Behaviour of Test Particles in a Quasi-Spherical Spacetime and the Physical Meaning of Superenergy

We calculate the instantaneous proper radial acceleration of test particles (as measured by a locally defined Lorentzian observer) in a Weyl spacetime, close to the horizon. As expected from the Israel theorem, there appear some bifurcations with respect to the spherically symmetric case (Schwarzschild), which are explained in terms of the behaviour of the superenergy, bringing out the physical relevance of this quantity in the study of general relativistic systems.Comment: 14 pages, Latex. 4 figures. New references added. Typos corrected. To appear in Int. J. Theor. Phy

Nonlinear electrophoresis of dielectric and metal spheres in a nematic liquid crystal

Electrophoresis is a motion of charged dispersed particles relative to a fluid in a uniform electric field. The effect is widely used to separate macromolecules, to assemble colloidal structures, to transport particles in nano- and micro-fluidic devices and displays. Typically, the fluid is isotropic (for example, water) and the electrophoretic velocity is linearly proportional to the electric field. In linear electrophoresis, only a direct current (DC) field can drive the particles. An alternate current (AC) field is more desirable because it allows one to overcome problems such as electrolysis and absence of steady flows. Here we show that when the electrophoresis is performed in a nematic fluid, the effect becomes strongly non-linear with a velocity component that is quadratic in the applied voltage and has a direction that generally differs from the direction of linear velocity. The new phenomenon is caused by distortions of the LC orientation around the particle that break the fore-aft (or left-right) symmetry. The effect allows one to transport both charged and neutral particles, even when the particles themselves are perfectly symmetric (spherical), thus enabling new approaches in display technologies, colloidal assembly, separation, microfluidic and micromotor applications.Comment: 15 pages, 4 figure

DVINO: A RISC-V vector processor implemented in 65nm technology

This paper describes the design, verification, implementation and fabrication of the Drac Vector IN-Order (DVINO) processor, a RISC-V vector processor capable of booting Linux jointly developed by BSC, CIC-IPN, IMB-CNM (CSIC), and UPC. The DVINO processor includes an internally developed two-lane vector processor unit as well as a Phase Locked Loop (PLL) and an Analog-to-Digital Converter (ADC). The paper summarizes the design from architectural as well as logic synthesis and physical design in CMOS 65nm technology.The DRAC project is co-financed by the European Union Regional Development Fund within the framework of the ERDF Operational Program of Catalonia 2014-2020 with a grant of 50% of total eligible cost. The authors are part of RedRISCV which promotes activities around open hardware. The Lagarto Project is supported by the Research and Graduate Secretary (SIP) of the Instituto Politecnico Nacional (IPN) from Mexico, and by the CONACyT scholarship for Center for Research in Computing (CIC-IPN).Peer ReviewedArticle signat per 43 autors/es: Guillem Cabo∗, Gerard Candón∗, Xavier Carril∗, Max Doblas∗, Marc Domínguez∗, Alberto González∗, Cesar Hernández†, Víctor Jiménez∗, Vatistas Kostalampros∗, Rubén Langarita∗, Neiel Leyva†, Guillem López-Paradís∗, Jonnatan Mendoza∗, Francesco Minervini∗, Julian Pavón∗, Cristobal Ramírez∗, Narcís Rodas∗, Enrico Reggiani∗, Mario Rodríguez∗, Carlos Rojas∗, Abraham Ruiz∗, Víctor Soria∗, Alejandro Suanes‡, Iván Vargas∗, Roger Figueras∗, Pau Fontova∗, Joan Marimon∗, Víctor Montabes∗, Adrián Cristal∗, Carles Hernández∗, Ricardo Martínez‡, Miquel Moretó∗§, Francesc Moll∗§, Oscar Palomar∗§, Marco A. Ramírez†, Antonio Rubio§, Jordi Sacristán‡, Francesc Serra-Graells‡, Nehir Sonmez∗, Lluís Terés‡, Osman Unsal∗, Mateo Valero∗§, Luís Villa† // ∗Barcelona Supercomputing Center (BSC), Barcelona, Spain. Email: [email protected]; †Centro de Investigación en Computación, Instituto Politécnico Nacional (CIC-IPN), Mexico City, Mexico; ‡ Institut de Microelectronica de Barcelona, IMB-CNM (CSIC), Spain. Email: [email protected]; §Universitat Politecnica de Catalunya (UPC), Barcelona, Spain. Email: [email protected] (author's final draft

Evaluación in vitro de la actividad antibacteriana de los extractos etanólicos de Uncaria tomentosa; Piper aduncun; Artemisa absinthium frente a Escherichia coli ATCC 25922

Las plantas han sido utilizadas tradicionalmente con fines medicinales y son un recurso valioso para encontrar nuevas moléculas con actividad farmacológica ante afecciones de origen microbiológico, especialmente de tipo bacteriana y que actualmente constituyen un problema de salud pública, principalmente por la resistencia adquirida de los microorganismos a los fármacos usados en su tratamiento habitual y otros factores que contribuyen al surgimiento de cepas resistentes. El objetivo del presente estudio fue la evaluación in-vitro de la actividad antibacteriana de los extractos etanólicos de las plantas Uncaria tomentosa (uña de gato), Piper aduncum (matico), y Artemisa absinthium (ajenjo) frente a la cepa de Escherichia coli (E coli) ATCC 25922. Los extractos vegetales fueron obtenidos mediante el método de maceración, usando como solvente el etanol al 96%; se identificaron los principales metabolitos secundarios presentes en los extractos obtenidos mediante reacciones cualitativas específicas para confirmar la presencia de dichos compuestos y posteriormente se evaluó la actividad antibacteriana mediante el método de microdilución en placa estandarizado por: Clinical and Laboratory Standards Institute (CLSI) M100 29th ed., para determinar la concentración mínima inhibitoria (MIC) de los extractos alcohólicos frente a E. coli. El estudio fue de tipo exploratorio y experimental, obteniéndose los siguientes resultados: Uncaria tomentosa presentó una concentración mínima inhibitoria (CMI) a los 625 µg/ml, mientras que para el caso de Artemisia absinthium y Piper aduncum no se evidenció efecto bactericida, sin embargo, se observó una disminución leve en el crecimiento bacteriano, por lo que podría sugerirse que estas plantas poseen un efecto bacteriostático.The plants have been used traditionally for medicinal purposes and could constitute a valuable resource to find new molecules with pharmacological activity in the face of conditions of microbiological origin, especially with the bacterial type. Those that currently constitute a public health problem, mainly due to the resistance acquired from microorganisms to the drugs used in their usual treatment and other factors that contribute to the emergence of resistant bacteria. The purpose of this research was the in-vitro evaluation of the antibacterial activity of ethanol extracts of ethanol plants of Uncaria tomentosa (cat's claw), Piper aduncum (matico), and Artemisa absinthium (wormwood) against the strain of E Coli ATCC 25922. The plant extracts were obtained through the maceration method using 96% ethanol as a solvent. The main functional groups present in the extracts obtained were identified by specific qualitative reactions to confirm the species and subsequently, the antibacterial activity was evaluated by the method of microdilution on the plate standardized by Clinical and Laboratory Standards Institute (CLSI) M100 29 to determine the minimum inhibitory concentration (MIC) of alcoholic extracts against E. coli. The research was exploratory and experimental. It shows the following results: Uncaria tomentosa had a minimum inhibitory concentration (MIC) at 625 µg/ml, while the case of Artemisia absinthium and Piper aduncum no bactericidal effect was observed; however, a slight decrease was observed in bacterial growth so it could arise to hurt that these plants have a bacteriostatic effect.Bioquímico FarmacéuticoCuenc

Induced-charge electro-osmosis around metal and Janus spheres in water: Patterns of flow and breaking symmetries

We establish experimentally the flow patterns of induced-charge electro-osmosis around immobilized metallic spheres in aqueous electrolyte. The ac field modifies local electrolyte concentration and causes quadrupolar flows with inward velocities being smaller than the outward ones. At high fields, the flow becomes irregular, with vortices smaller than the size of the sphere. Janus metallodielectric spheres create dipolar flows and pump the fluid from the dielectric toward the metallic part. The experimentally determined far-field flows decay with distance as r-3

Liquid crystal-enabled electro-osmosis through spatial charge separation in distorted regions as a novel mechanism of electrokinetics

Electrically controlled dynamics of fluids and particles at microscales is a fascinating area of research with applications ranging from microfluidics and sensing to sorting of biomolecules. The driving mechanisms are electric forces acting on spatially separated charges in an isotropic medium such as water. Here, we demonstrate that anisotropic conductivity of liquid crystals enables new mechanism of highly efficient electro-osmosis rooted in space charging of regions with distorted orientation. The electric field acts on these distortion-separated charges to induce liquid crystal-enabled electro-osmosis. Their velocities grow with the square of the field, which allows one to use an alternating current field to drive steady flows and to avoid electrode damage. Ionic currents in liquid crystals that have been traditionally considered as an undesirable feature in displays, offer a broad platform for versatile applications such as liquid crystal-enabled electrokinetics, micropumping and mixing