Efficient time series detection of the strong stochasticity threshold in Fermi-Pasta-Ulam oscillator lattices

In this work we study the possibility of detecting the so-called strong stochasticity threshold, i.e. the transition between weak and strong chaos as the energy density of the system is increased, in anharmonic oscillator chains by means of the 0-1 test for chaos. We compare the result of the aforementioned methodology with the scaling behavior of the largest Lyapunov exponent computed by means of tangent space dynamics, that has so far been the most reliable method available to detect the strong stochasticity threshold. We find that indeed the 0-1 test can perform the detection in the range of energy density values studied. Furthermore, we determined that conventional nonlinear time series analysis methods fail to properly compute the largest Lyapounov exponent even for very large data sets, whereas the computational effort of the 0-1 test remains the same in the whole range of values of the energy density considered with moderate size time series. Therefore, our results show that, for a qualitative probing of phase space, the 0-1 test can be an effective tool if its limitations are properly taken into account.Comment: 5 pages, 2 figures; accepted for publication in Physical Review

Evolution of Daily Gene Co-expression Patterns from Algae to Plants

Daily rhythms play a key role in transcriptome regulation in plants and microalgae orchestrating responses that, among other processes, anticipate light transitions that are essential for their metabolism and development. The recent accumulation of genome-wide transcriptomic data generated under alternating light:dark periods from plants and microalgae has made possible integrative and comparative analysis that could contribute to shed light on the evolution of daily rhythms in the green lineage. In this work, RNA-seq and microarray data generated over 24 h periods in different light regimes from the eudicot Arabidopsis thaliana and the microalgae Chlamydomonas reinhardtii and Ostreococcus tauri have been integrated and analyzed using gene co-expression networks. This analysis revealed a reduction in the size of the daily rhythmic transcriptome from around 90% in Ostreococcus, being heavily influenced by light transitions, to around 40% in Arabidopsis, where a certain independence from light transitions can be observed. A novel Multiple Bidirectional Best Hit (MBBH) algorithm was applied to associate single genes with a family of potential orthologues from evolutionary distant species. Gene duplication, amplification and divergence of rhythmic expression profiles seems to have played a central role in the evolution of gene families in the green lineage such as Pseudo Response Regulators (PRRs), CONSTANS-Likes (COLs), and DNA-binding with One Finger (DOFs). Gene clustering and functional enrichment have been used to identify groups of genes with similar rhythmic gene expression patterns. The comparison of gene clusters between species based on potential orthologous relationships has unveiled a low to moderate level of conservation of daily rhythmic expression patterns. However, a strikingly high conservation was found for the gene clusters exhibiting their highest and/or lowest expression value during the light transitions

Conserved gene modules regulate light signals in algae and plants

In the Plant Development Unit (PDU) we aim to discover mechanisms that allowed photosynthetic organisms to reach the level of developmental complexity shown today. Plants are particularly good models as they have been evolving as light autotrophs for millions of years, ever since the first bacteria developed oxygenic photosynthesis and killed 99% of existing species in the process. But light is not only the main source of energy for plants, it is also one of the main regulators of their development, as endo-symbiotic cyanobacteria (chloroplasts) perfected their physiological synchronization with the emerging eukaryotes (1). Another important aspect of plant evolution was the transit to the aerial world and the acquisition of characteristics that allowed them to successfully colonise this new habitat (2). In the PDU we have followed the evolution of the day length response (photoperiod) that coordinates the daily physiological activities of plants and can be also used to regulate seasonal behaviours such as winter recesses or flowering time (3). When gene expression networks from photoperiod experiments from microalgae, bryophytes and higher plants are compared, a common nodular structure is discovered (4). Following these discoveries, we have isolated ancestor algal genes that show the same function as higher plants in the response to photoperiod such as the CONSTANS-DOF module (5). We are currently investigating common regulatory mechanisms in photoperiod sensing such as the effect on the circadian clock, senescence, retrograde signalling (6) and protein stability (7

Representaciones sociales de los docentes sobre la enseñanza de los contenidos de Matemática en los programas de Ingeniería de la UNEFM

La investigación tuvo como propósito identificar las representaciones sociales de los docentes sobre la enseñanza de los contenidos de Matemática II en los programas de ingeniería de la Universidad Nacional Experimental Francisco de Miranda (UNEFM). Los informantes claves fueron tres docentes cuya carga académica incluyó cursos de dicha unidad curricular. Bajo el paradigma cualitativo, se desarrolló el procedimiento descrito por Moscovici (1961, 1979) y Abric (1996) para identificar las representaciones sociales del proceso de enseñanza de los contenidos de Matemática II haciendo énfasis en la estructura del campo de la representación desde la teoría del núcleo central. Con la información recolectada se procedió al análisis estructural con la técnica de escalerización para el cálculo de los índices de centralidad, prestigio y abstracción. Respecto a los hallazgos, los docentes están conscientes, y se encuentra muy arraigado en su núcleo central el uso de estrategias en su planificación que favorezca el aprendizaje duradero y con significado. Los mismos docentes se han percatado que ha llegado el momento de dejar a un lado el uso de estrategias y recursos tradicionales y desarrollar otras formas para presentar a los estudiantes la importancia que merece las relaciones de los contenidos con la realidad a través de las diversas aplicaciones puesto que los mismos quedan desvinculados de la problemática que se aborda en las diferentes ingenierías

A new and simple variable-angle accessory for infrared specular reflectance

A simple, low-cost accessory (patent pending) with only two flat mirrors and a new variable-angle mechanism has been developed for infrared specular reflectance measurements. The system allows the angles of incidence to be varied continuously from 15° (near normal incidence) to 85° (near grazing angle) without losing the alignment of the accessory. The reflectivity of boron nitride thin films deposited on metallic substrates has been measured at different angles of incidence to demonstrate the utility of this accessory

Radionuclide Determination In Surface Water Samples By Inductively Coupled Plasma With Sector Field Mass Spectrometry (ICP-SFMS)

The determination of naturally occurring radionuclides in the environment by inductively coupled plasma mass spectrometry of high resolution (ICP-SFMS) has gained recognition over the last fifteen years, relative to the radiometric techniques, as the result of improvement in instrumental performance, sample introduction equipment and sample preparation. With the increase in instrumental sensitivity, it is now possible to measure ultratrace levels of many radioisotopes.The aim of this work was to determined the natural radionuclides (232Th, 234U, 235U and 238U) in surface water using Inductively Coupled Plasma-Sector Field Mass Spectrometry (ICP-SFMS). The samples were sampling from Lerma river, State of Mexico at february to april 2015. The process of treatment of sample consisted in perform an acid digestion according to the 3015A USEPA method followed of the direct measurement in ICP-SFMS. Results obtained were: a) identify the presence of 232Th, 234U, 235U and 238U isotopes in water, b) isotopic ratios were for 234U/238U=1.133 ± 0.016. ICP-SFMS has gained popularity in the field of radiochemistry, particularly as a method of detection for long lived-actinides

Glycerol Valorization towards a Benzoxazine Derivative through a Milling and Microwave Sequential Strategy

Glycerol and aminophenol intermolecular condensation has been investigated through a milling and microwave-assisted sequential strategy, towards the synthesis of a benzoxaxine derivative. Mechanochemical activation prior to the microwave-assisted process could improve the probability of contact between the reagents, and greatly favors the higher conversion of aminophenol. At the same time, following a mechanochemical–microwave sequential approach could tune the selectivity towards the formation of a benzoxazine derivative, which could find application in a wide range of biomedical area

Investigación de operaciones I : 1a. parte

1 archivo PDF (285 páginas) ; 2a edición 2000, 4a reimpresión 2004Material para el programa de la materia de Investigación de Operaciones I que imparte el Departamento de Sistemas de la División de Ciencias Básicas e Ingeniería de la UAM-A. Con el objetivo de proporcionar los elementos analíticos necesarios para la formulación, análisis y solución de problemas de programación lineal y familiarizarlo con los fundamentos teóricos y ventajas computacionales de los métodos de solución

Detection of Atrial Fibrillation Driver Locations Using CNN and Body Surface Potentials

[EN] Atrial fibrillation (AF) is characterized by complex and irregular propagation patterns, and AF onset locations and drivers responsible for its perpetuation are main targets for ablation procedures. Several Deep Learningbased methods have proposed to detect AF, but the estimation of the atrial area where the drivers are found is a topic where further research is needed. In this work, we propose to estimate the zone where AF drivers are found from body surface potentials (BSPs) and Convolutional Neural Networks (CNN), modeling a supervised classification problem. Accuracy in the test set was 0.89 when using noisy BSPs (SNR=20dB), while the Cohen¿s Kappa was 0.85. Therefore, the proposed method could help to identify target regions for ablation using a non-invasive procedure, and avoiding the use of ECG Imaging (ECGI).This work has been partially supported by: Ministerio de Ciencia e Innovacion (PID2019-105032GB-I00), Instituto de Salud Carlos III, and Ministerio de Ciencia, Innovacion y Universidades (supported by FEDER Fondo Europeo de Desarrollo Regional PI17/01106 and RYC2018-024346B-750), Consejeria de Ciencia, Universidades e Innovacion of the Comunidad de Madrid through the program RIS3 (S-2020/L2-622), EIT Health (Activity code 19600, EIT Health is supported by EIT, a body of the European Union) and the European Union's Horizon 2020 research and innovation program under the Marie Skodowska-Curie grant agreement No. 860974.Cámara-Vázquez, MÁ.; Hernández-Romero, I.; Morgado-Reyes, E.; Guillem Sánchez, MS.; Climent, AM.; Barquero-Pérez, Ó. (2021). Detection of Atrial Fibrillation Driver Locations Using CNN and Body Surface Potentials. 1-4. https://doi.org/10.22489/CinC.2021.2561