A note on the geodesic deviation equation for null geodesics in the Schwarzschild black-hole

We use the Hamiltonian formulation of the geodesic equation in the Schwarzschild space-time so as to get the variational equation as the counterpart of the Jacobi equation in this approach. In this context we are able to apply the Morales-Ramis theorem to link the integrability of the geodesic equation to the integrability, in the sense of differential Galois theory, of the variational equation. This link is strong enough to hold even on geodesics for which the usual conserved quantities fail to be independent, as is the case of circular geodesics. We show explicitly the particular cases of some null geodesics and their variational equations.Comment: 12 page

Práctica de desarrollo de interfaces hardware/software para la monitorización del estado de un PC

Este artículo presenta una práctica laboratorio impartida mediante una metodología de aprendizaje basado en proyectos (ABP) [1] para dotar de la capacidad de diseñar y desarrollar un monitor del estado de un ordenador, integrado en un sistema empotrado que se comunica con una aplicación de escritorio, a nuestros alumnos de la asignatura de Diseño de Microcontroladores (DM) en el contexto del Máster en Ingeniería de Computadores y Redes. Esta práctica abarca la comunicación Hardware/ Software entre un microcontrolador con un núcleo Cortex-M4 y una aplicación software escrita en lenguaje C# usando el entorno Visual Studio Community 2015 a través de puertos series virtuales (VCP). Esta práctica está enfocada como un proyecto que los alumnos han de ir realizando desde cero, avanzando mediante la consecución de hitos, hasta conseguir obtener un sistema final. El sistema a desarrollar se divide en dos partes, por un lado tenemos un PC con un sistema operativo de la familia Windows, en el que se construye una aplicación visual mediante Windows Forms, la cual obtiene información del sistema de forma periódica y la envía al microcontrolador mediante comandos usando el puerto serie (USB o comunicación Bluetooth). Por otro lado tenemos un microcontrolador de la familia STM32 que dispone de un display LCD ejecutando una plataforma completamente libre, .NET Micro Framework, la cual recibe a través del puerto serie la información obtenida gracias a la aplicación software del PC y la muestra en la pantalla, obteniendo así una herramienta de monitorización del PC sin tener que estar conectado físicamente a éste. El desarrollo de este tipo de proyectos se añade la dificultad de la necesidad del uso de diferentes herramientas para el desarrollo del firmware y del software en paralelo, de manera incremental, y enfocadas para ámbitos de uso muy distintos. Esta práctica ha tenido una gran acogida por parte de los alumnos, ya que les ha servido de ejemplo del desarrollo de firmware para un microcontrolador usando la plataforma .NET MF y de su comunicación con el PC por medio de una aplicación visual.This manuscript presents a practical laboratory session imparted using a project-based learning methodology (PBL) to provide the capacity of designing and developing a computer status monitoring device, integrated in an embedded system that communicates with a desktop software tool, to our students in the Computer Engineering Master’s Degree. This practice session encompasses Hardware/ Software communication between a microcontroller with a Cortex-M4 kernel and a desktop software application through virtual COM ports (VCP) written in C# using Visual Studio Community 2015. This lab session is focused as a project that students must be making from scratch by achieving and completing some milestones to obtain a final functional system. The project is divided into two different parts. First, we have a Windows PC where a visual software application that gathers information from the system and sends it periodically to the microcontroller (USB or Bluetooth) has to be built using Windows Forms. On the other hand, we have a microcontroller from the STM32 family that has a 2.4’ LCD display executing .NET Micro Framework that receives the information obtained from the PC through the serial port and displays it in the screen. This way, students create a computer status monitoring tool that does not need to be connected physically to it to receive the information. The development of this project is added to the need of using different tools for firmware and software development, focused to very different fields of use. This practice has been well received by the students, because it has served as an example of the firmware development for a microcontroller using the .NET MF platform as well as the communication between the PC and the microcontroller using a visual software application

Stiff‐Stilbene Ligands Target G‐Quadruplex DNA and Exhibit Selective Anticancer and Antiparasitic Activity

G-quadruplex nucleic acid structures have long been studied as anticancer targets whilst their potential in antiparasitic therapy has only recently been recognized and barely explored. Herein, we report the synthesis, biophysical characterization, and in vitro screening of a series of stiff-stilbene G4 binding ligands featuring different electronics, side-chain chemistries, and molecular geometries. The ligands display selectivity for G4 DNA over duplex DNA and exhibit nanomolar toxicity against Trypasanoma brucei and HeLa cancer cells whilst remaining up to two orders of magnitude less toxic to non-tumoral mammalian cell line MRC-5. Our study demonstrates that stiff-stilbenes show exciting potential as the basis of selective anticancer and antiparasitic therapies. To achieve the most efficient G4 recognition the scaffold must possess the optimal electronics, substitution pattern and correct molecular configuration.M.P.O. thanks the Bristol Chemical Synthesis Centre for Doctoral Training, funded by EPSRC (EP/L015366/1) and the University of Bristol for a PhD studentship. J.C.M./P.P. thank Spanish Ministerio de Ciencia Innovación y Universidades (Grants CTQ2015- 64275-P and RTI2018-099036-B-I00). M.C.G. thanks the European Research Council (ERC-COG: 648239

Analysis of Game Actions and Performance in Young Soccer Players: A Study Using Sequential Analysis

The objective of this research is to analyze the performance of actions in a reduced game situation in a sample of young soccer players. This is a game format in which possession of the ball has to be maintained. The sample consisted of 85 young players aged between 12 and 16 years, observing a total of 58 reduced games and using an analysis instrument called the Game Performance Assessment Instrument (GPAI). The essential data quality analyses are carried out, including the use of correlation indexes, Cohen’s Kappa and the Phi index for intra- and inter-observer reliability. Generalizability and invariance analyses are also performed to estimate the reliability, validity and precision of the numerical structure and its generalizability to other samples or populations with similar distributions. An observational design of nomothetic, punctual and multidimensional types is used, and subsequently, a sequential analysis of the game actions is carried out from the observations. The results show significant relationships between decision-making behaviors (adequate and inadequate) and technical execution behaviors (adequate and inadequate). The findings have highlighted a clear relationship of interdependence between technical execution and decision making. This information is very useful for the design and planning of training oriented to the optimization of sport performance in soccer.Partial funding for open access charge: Universidad de Málag

Real-time detection of uncalibrated sensors using Neural Networks

Nowadays, sensors play a major role in several contexts like science, industry and daily life which benefit of their use. However, the retrieved information must be reliable. Anomalies in the behavior of sensors can give rise to critical consequences such as ruining a scientific project or jeopardizing the quality of the production in industrial production lines. One of the more subtle kind of anomalies are uncalibrations. An uncalibration is said to take place when the sensor is not adjusted or standardized by calibration according to a ground truth value. In this work, an online machine-learning based uncalibration detector for temperature, humidity and pressure sensors was developed. This solution integrates an Artificial Neural Network as main component which learns from the behavior of the sensors under calibrated conditions. Then, after trained and deployed, it detects uncalibrations once they take place. The obtained results show that the proposed solution is able to detect uncalibrations for deviation values of 0.25 degrees, 1% RH and 1.5 Pa, respectively. This solution can be adapted to different contexts by means of transfer learning, whose application allows for the addition of new sensors, the deployment into new environments and the retraining of the model with minimum amounts of data

Enhanced sampling molecular dynamics simulations correctly predict the diverse activities of a series of stiff-stilbene G-quadruplex DNA ligands

Ligands with the capability to bind G-quadruplexes (G4s) specifically, and to control G4 structure and behaviour, offer great potential in the development of novel therapies, technologies and functional materials. Most known ligands bind to a pre-formed topology, but G4s are highly dynamic and a small number of ligands have been discovered that influence these folding equilibria. Such ligands may be useful as probes to understand the dynamic nature of G4 in vivo, or to exploit the polymorphism of G4 in the development of molecular devices. To date, these fascinating molecules have been discovered serendipitously. There is a need for tools to predict such effects to drive ligand design and development, and for molecular-level understanding of ligand binding mechanisms and associated topological perturbation of G4 structures. Here we study the G4 binding mechanisms of a family of stiff-stilbene G4 ligands to human telomeric DNA using molecular dynamics (MD) and enhanced sampling (metadynamics) MD simulations. The simulations predict a variety of binding mechanisms and effects on G4 structure for the different ligands in the series. In parallel, we characterize the binding of the ligands to the G4 target experimentally using NMR and CD spectroscopy. The results show good agreement between the simulated and experimentally observed binding modes, binding affinities and ligand-induced perturbation of the G4 structure. The simulations correctly predict ligands that perturb G4 topology. Metadynamics simulations are shown to be a powerful tool to aid development of molecules to influence G4 structure, both in interpreting experiments and to help in the design of these chemotypes

Los documentos de idoneidad técnica como potenciales incentivadotes de la industrialización de la construcción.

Los documentos de idoneidad técnica como potenciales incentivadotes de la industrialización de la construcción

Assessing vulnerability of functional diversity to species loss: a case study in Mediterranean agricultural systems

"This is the peer reviewed version of the following article: Functional Ecology 31.2 (2017): 427-435, which has been published in final form at https://doi.org/10.1111/1365-2435.12709. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions"Increasing land-use intensification is leading to biodiversity losses world-wide, which can reduce the functioning of ecosystems. However, it is increasingly clear that not all species are equally important for ecosystem processes: whereas the loss of a functionally unique species may reduce the capacity of the community to perform some functions, losing a functionally redundant species should have a much smaller impact. Assessing the vulnerability of functional diversity (FD) to species extinctions can help to predict the impacts of land-use intensification. This approach consists in ranking species according to their risk of extinction and then estimating the trajectory followed by FD as species are lost from local communities. However, the most widely used FD indices are not independent of species richness, being much more sensitive to the loss of species in species-poor than in species-rich sites. This may result in misleading interpretations, affecting our ability to rank communities according to the vulnerability of their FD to species loss, by confounding it with the initial level of species richness. Here, we propose comparing the trajectory of FD under the most plausible order of species loss with that followed under random species losses as an effective way to remove the trivial effect of species richness in the assessments of vulnerability to species loss. After decoupling vulnerability from species richness, we used it to analyse the effect of agricultural intensification on the vulnerability of arable plant communities in Mediterranean agricultural fields. Our results show that management strategies aiming to increase the functionality of these systems should focus on intermediately intensified fields, where small reductions in the level of intensification are likely to benefit arable plant diversity, increasing the number of species and FD and decreasing the vulnerability of FD to species losses. Removing the effect of species richness is essential to attain unbiased estimations of the vulnerability of communities to species loss, especially when species-poor communities are considered. Combining vulnerability with information on taxonomic and functional diversity appears as a promising tool to inform decision-making processes, anticipating the effects of local extinction

Bio-inspired computational memory model of the Hippocampus: an approach to a neuromorphic spike-based Content-Addressable Memory

The brain has computational capabilities that surpass those of modern systems, being able to solve complex problems efficiently in a simple way. Neuromorphic engineering aims to mimic biology in order to develop new systems capable of incorporating such capabilities. Bio-inspired learning systems continue to be a challenge that must be solved, and much work needs to be done in this regard. Among all brain regions, the hippocampus stands out as an autoassociative short-term memory with the capacity to learn and recall memories from any fragment of them. These characteristics make the hippocampus an ideal candidate for developing bio-inspired learning systems that, in addition, resemble content-addressable memories. Therefore, in this work we propose a bio-inspired spiking content-addressable memory model based on the CA3 region of the hippocampus with the ability to learn, forget and recall memories, both orthogonal and non-orthogonal, from any fragment of them. The model was implemented on the SpiNNaker hardware platform using Spiking Neural Networks. A set of experiments based on functional, stress and applicability tests were performed to demonstrate its correct functioning. This work presents the first hardware implementation of a fully-functional bio-inspired spiking hippocampal content-addressable memory model, paving the way for the development of future more complex neuromorphic systems.Comment: 15 pages, 5 figures, journal, Spiking Neural Networ