Machine learning identification of piezoelectric properties.

The behavior of a piezoelectric element can be reproduced with high accuracy using numerical simulations. However, simulations are limited by knowledge of the parameters in the piezoelectric model. The identification of the piezoelectric model can be addressed using different techniques but is still a problem for manufacturers and end users. In this paper, we present the use of a machine learning approach to determine the parameters in the model. In this first work, the main sensitive parameters, c11, c13, c33, c44 and e33 were predicted using a neural network numerically trained by using finite element simulations. Close to one million simulations were performed by changing the value of the selected parameters by ±10% around the starting point. To train the network, the values of a PZT 27 piezoelectric ceramic with a diameter of 20 mm and thickness of 2 mm were used as the initial seed. The first results were very encouraging, and provided the original parameters with a difference of less than 0.6% in the worst case. The proposed approach is extremely fast after the training of the neural network. It is suitable for manufacturers or end users that work with the same material and a fixed number of geometries

Neural Unbalanced Optimal Transport via Cycle-Consistent Semi-Couplings

Comparing unpaired samples of a distribution or population taken at different points in time is a fundamental task in many application domains where measuring populations is destructive and cannot be done repeatedly on the same sample, such as in single-cell biology. Optimal transport (OT) can solve this challenge by learning an optimal coupling of samples across distributions from unpaired data. However, the usual formulation of OT assumes conservation of mass, which is violated in unbalanced scenarios in which the population size changes (e.g., cell proliferation or death) between measurements. In this work, we introduce NubOT, a neural unbalanced OT formulation that relies on the formalism of semi-couplings to account for creation and destruction of mass. To estimate such semi-couplings and generalize out-of-sample, we derive an efficient parameterization based on neural optimal transport maps and propose a novel algorithmic scheme through a cycle-consistent training procedure. We apply our method to the challenging task of forecasting heterogeneous responses of multiple cancer cell lines to various drugs, where we observe that by accurately modeling cell proliferation and death, our method yields notable improvements over previous neural optimal transport methods

A physical-chemical study of water resources in 5 hydropower projects: Estudo físico-químico de recursos hídricos em 5 projetos hidrelétricos

Over the last 60 years, renewable energies have substantially developed; in 2021, around 12.8% of global primary energy came from these technologies. Thus, even though renewable energies have good global acceptance present challenges in quantifying the environmental, social, and cultural effects, generating a lack of knowledge of the impact caused. Nowadays, hydropower is the renewable source with the most significant participation; at the end of 2020, the hydropower installed capacity worldwide was 1,330 GW, and 4,370 TWh were generated in that year. Therefore, the manuscript aims to determine if there are changes in water quality due to the use of hydropower generation in five projects distributed in Ecuador, Argentina, and Uruguay. The methodology is quantitative experimental; experimental because it takes water samples to measure parameters and qualitatively compares the lab results to do statistical analyses. Based on the ten samples gathered, it concluded that from 14 physical and chemical parameters, the principal divergences fluctuated in the presence of dissolved solids (26%), total solids (21%), bicarbonates (15%), total hardness (14%), suspended solids (6%), and sodium (4%). Additionally, values show organic matter existence due to vegetation decomposition, and metabolites formed in dams such as Salto Grande, Hidroagoyan, Minas San Francisco, Baba, and Coca Codo Sinclair.&nbsp

Una propuesta interdisciplinar para trabajar la competencia digital docente en el Grado de Educación Infantil (UPV/EHU)

In the pandemic occurred in the new millennium it has become clear the presence and importance of Information and Communication Technologies in the day-to-day life, including early childhood. Therefore, the initial teacher training must consider the development of digital teaching competence (DTC). Because of that, in the second year of the Degree in Early Childhood Education a multidisciplinary work called "Influence of Screens in Childhood" is proposed. This case study analyses if this proposal facilitates the development of DTC. The sample consists of 166 university students. The content of digital concept maps has been analysed in relation to students' reflection about the influence of screens. The analysis of the oral presentations of their conclusions has been carried out through an observation scale and a self-assessment scale. From the realised analysis, it is concluded that the DTC of future teachers and the approach to the digital world have been successfully achieved thanks to the model on which the proposal is based. However, it is also clear that the possibility of transferring these results will depend on future research located in different contexts, which use other interfaces, or are related to other Degrees

Factores asociados a la calidad en la toma de la muestra de Papanicolau por el personal de enfermería del Puesto de Salud Elvira Rugama, SILAIS Granada II Semestre 2014

El Papanicolaou es un estudio sencillo con que se examinan células del cérvix, y es capaz de detectar células atípicas del epitelio cervical. Se desarrolló en los años 30 y lleva el nombre de su inventor el Dr. George Papanicolaou. La citología Cervico Uterina Papanicolaou hoy en día se considera como una poderosa herramienta exitosa para el diagnóstico precoz del cáncer cuello uterino y a partir de su descubrimiento en donde el valor predictivo negativo es el parámetro que más se utiliza en la evaluación de su efectividad, para la detección del cáncer antes mencionada. Los falsos negativos son el principal problema del tamizaje y su principal explicación se debe a una redacción y una lectura realizada en forma inadecuada en los establecimientos y laboratorios en los sistemas de salud. El Papanicolaou es altamente utilizado en las instituciones de salud es un método fácil de realizar, de régimen ambulatorio, inocuo, de bajo costo y de una eficacia de hasta un 95%, si se realiza e interpreta de forma correcta, sin embargo a pesar de sus beneficios en pleno sigo XXI muchas mujeres continúan negándose a realizar la toma, estudios demuestran que las mujeres a quienes no se le realiza esta prueba tiene mayor riesgo de padecer Cáncer invasor de las que si se le práctica. (Noma de prevención del cáncer cervico uterino edición 2000.MINSA). Este estudio se realizó abordando algunos factores que inciden en la calidad de la muestra del Papanicolaou que realiza el personal de enfermería en el puesto Salud Elvira Rugama II semestre 201

Diseño, construcción y evaluación de un analizador autónomo in situ para la monitorización de los niveles de fósforo y nitrógeno en aguas superficiales. Primeros resultados.

Se describe un prototipo de analizador automatizado de bajo costo capaz de operar in situ junto a un cuerpo de agua realizando la determinación analítica de los niveles de fósforo (ortofosfato) y nitrógeno (nitrato+nitrito), así como pH y temperatura, transmitiendo los resultados obtenidos a una estación remota mediante internet inalámbrica. Las determinaciones de fósforo y nitrógeno son realizadas mediante métodos de desarrollo de color con detección fotométrica implementados en un sistema de flujo pulsado. Para el control y adquisición de datos se recurrió a la plataforma de microcontroladores Arduino. El sistema opera con baterías recargables y habilita el uso de un panel solar para su recarga. La evaluación preliminar de los métodos analíticos realizada en el laboratorio arrojó cifras de mérito perfectamente adecuadas para los fines buscados. Está prevista una evaluación de campo donde se estudiará el desempeño del equipo en condiciones reales. Se entiende que el uso de este tipo de sistemas que no requieren personal para su operación puede resultar de utilidad en el análisis ambiental.A prototype of a low-cost automated analyser capable of in situ operation next to a water body is described. The analyser can determine levels of phosphorus (orthophosphate) and nitrogen (nitrate+nitrite), along with pH and temperature, transmitting the results to a remote station via wireless internet. Phosphorus and nitrogen determinations are carried out by means of photometric methods, implemented in a pulsed-flow system. For control and data acquisition the open-source Arduino platform of microcontrollers was used. The system runs on rechargeable batteries, with the possible support of a solar panel. Preliminary evaluation of the analytical methods carried out in the laboratory showed figures of merit fit for the purpose. A field evaluation is foreseen in the near future, where the analyser will be tested under real conditions. This type of instruments is considered to be potentially useful in environmental analysis

Genetic factors associated with population size may increase extinction risks and decrease colonization potential in a keystone tropical pine

Pioneer species are essential for forest regeneration and ecosystem resilience. Pinus chiapensis is an endangered pioneer key species for tropical montane cloud forest regeneration in Mesoamerica. Human activities have severely reduced some P. chiapensis populations, which exhibited a small or null colonization potential suggesting the involvement of genetic factors associated with small populations. We explored the relationships between (i) population genetic diversity (allozymes) and population size, including sampling size effects, (ii) fitness estimates associated with colonization potential (seed viability and seedling performance) in a common environment and population size, and (iii) fitness estimates and observed heterozygosity in populations with sizes spanning five orders of magnitude. All the estimates of genetic diversity and fitness increased significantly with population size. Low fitness was detected in progenies of small populations of disturbed and undisturbed habitats. Progenies with the lowest observed heterozygosity displayed the lowest fitness estimates, which, in turn, increased with heterozygosity, but seed viability peaked at intermediate heterozygosity values suggesting inbreeding and outbreeding depression. Inbreeding depression appears to be the most immediate genetic factor in population decline. Conservation efforts should try to maintain large and genetically diverse populations, enhance gene flow by restoring connectivity between adjacent populations, and avoid genetically distant individuals

Sn nanoparticles on gas diffusion electrodes: Synthesis, characterization and use for continuous CO2 electroreduction to formate

Electrochemical reduction of CO2 has been pointed out as an interesting strategy to convert CO2 into useful chemicals. In addition, coupling CO2 electroreduction with renewable energies would allow storing electricity from intermittent renewable sources such as wind or solar power. In this work, an easy and fast method is adapted for the synthesis of pure and carbon supported Sn nanoparticles. The resulting nanoparticles have been characterized by transmission electron microscopy and their electrocatalytic properties towards CO2 reduction evaluated by cyclic voltammetry. Carbon supported Sn nanoparticles have been subsequently used to prepare Gas Diffusion Electrodes (Sn/C-GDEs). The electrodes have been characterized by scanning electron microscopy and also by cyclic voltammetry. Finally, the electrodes were tested on a continuous and single pass CO2 electroreduction filter-press type cell system in aqueous solution, to obtain formate at ambient pressure and temperature. These Sn/C-GDEs allow working at high current densities with low catholyte flow. Thus, for instance, at 150 mA cm−2, a 70% Faradaic Efficiency (FE) was obtained with a formate concentration of 2.5 g L−1. Interestingly, by increasing the current density to 200 mA cm−2 and decreasing the flow rate, a concentration over 16 g L−1 was reached. Despite the high concentrations obtained, further research is still required to keep high FE operating at high current densities.This work was conducted under the framework of the Spanish Ministry of Economy and Competitiveness projects CTQ2013-48280-C3-1-R and CTQ2013-48280-C3-3-R. Andrés Del Castillo also acknowledges the research grant from University of Cantabria, co-financed by the Regional Government of Cantabria