On the use of machine learning algorithms in the measurement of stellar magnetic fields

Regression methods based in Machine Learning Algorithms (MLA) have become an important tool for data analysis in many different disciplines. In this work, we use MLA in an astrophysical context; our goal is to measure the mean longitudinal magnetic field in stars (H_ eff) from polarized spectra of high resolution, through the inversion of the so-called multi-line profiles. Using synthetic data, we tested the performance of our technique considering different noise levels: In an ideal scenario of noise-free multi-line profiles, the inversion results are excellent; however, the accuracy of the inversions diminish considerably when noise is taken into account. In consequence, we propose a data pre-process in order to reduce the noise impact, which consists in a denoising profile process combined with an iterative inversion methodology. Applying this data pre-process, we have found a considerable improvement of the inversions results, allowing to estimate the errors associated to the measurements of stellar magnetic fields at different noise levels. We have successfully applied our data analysis technique to two different stars, attaining by first time the measurement of H_eff from multi-line profiles beyond the condition of line autosimilarity assumed by other techniques.Comment: Accepted for publication in A&

Atmospheric mixing ratios of methyl ethyl ketone (2-butanone) in tropical, boreal, temperate and marine environments

Methyl ethyl ketone (MEK) enters the atmosphere following direct emission from vegetation and anthropogenic activities, as well as being produced by the gas-phase oxidation of volatile organic compounds (VOCs) such as n-butane. This study presents the first overview of ambient MEK measurements at six different locations, characteristic of forested, urban and marine environments. In order to understand better the occurrence and behaviour of MEK in the atmosphere, we analyse diel cycles of MEK mixing ratios, vertical profiles, ecosystem flux data, and HYSPLIT back trajectories, and compare with co-measured VOCs. MEK measurements were primarily conducted with proton transfer reaction–mass spectrometer (PTR-MS) instruments. Results from the sites under biogenic influence demonstrate that vegetation is an important source of MEK. The diel cycle of MEK follows that of ambient temperature and the forest structure plays an important role in air mixing. At such sites a high correlation of MEK with acetone was observed (e.g. r2 = 0.96 for the SMEAR-Estonia site in a remote hemi-boreal forest in Tartumaa, Estonia, and r2 = 0.89 at the ATTO pristine tropical rainforest site in central Amazonia). Under polluted conditions, we observed strongly enhanced MEK mixing ratios. Overall, the MEK mixing ratios and flux data presented here indicate that both biogenic and anthropogenic sources contribute to its occurrence in the global atmosphere

Spontaneous circadian rhythms in a cold-Adapted natural isolate of Aureobasidium pullulans

Indexación: Scopus.Circadian systems enable organisms to synchronize their physiology to daily and seasonal environmental changes relying on endogenous pacemakers that oscillate with a period close to 24 h even in the absence of external timing cues. The oscillations are achieved by intracellular transcriptional/translational feedback loops thoroughly characterized for many organisms, but still little is known about the presence and characteristics of circadian clocks in fungi other than Neurospora crassa. We sought to characterize the circadian system of a natural isolate of Aureobasidium pullulans, a cold-Adapted yeast bearing great biotechnological potential. A. pullulans formed daily concentric rings that were synchronized by light/dark cycles and were also formed in constant darkness with a period of 24.5 h. Moreover, these rhythms were temperature compensated, as evidenced by experiments conducted at temperatures as low as 10 °C. Finally, the expression of clock-essential genes, frequency, white collar-1, white collar-2 and vivid was confirmed. In summary, our results indicate the existence of a functional circadian clock in A. pullulans, capable of sustaining rhythms at very low temperatures and, based on the presence of conserved clock-gene homologues, suggest a molecular and functional relationship to well-described circadian systems.https://www.nature.com/articles/s41598-017-14085-

Introduction and evaluation of the ACS BCon basic course in Zaragoza, Spain

Background: The American College of Surgeons Bleeding Control Basic (BCon) course aimed at teaching hemorrhage control techniques in the USA had not yet been taught in Spain. The purpose of this study is to assess its implementation among students and healthcare employees in the Lozano Blesa University Hospital of Zaragoza, a middle-sized Spanish city. Methods: The study was conducted in a University Hospital and at the University of Zaragoza, scheduling four free B-Con sessions from 2017 to 2018. Two groups were identified as forming the population: healthcare employees and medical students. An anonymous questionnaire was completed at the end of the course regarding content, applicability, usefulness, relevance, and satisfaction. Study variables were ranked from 0 to 10: poor (when graded from 0 to 3), fair (4 to 6) and good (7 to 10). Results were compared between the groups, expressed in percentages and ¿ 2 tested to analyze significant differences if any. Results: Among the 83 individuals who completed the course, 46 were medical students and 37 healthcare employees; 61% women and 39% men; aged 21 years to 52 years. Attendees evaluated satisfaction with the highest grade (84%), followed by usefulness (73%), applicability (70%), and relevance (66%). There was no variable graded as poor. The comparison of perceptions between groups did not reveal statistical differences based on a 0.05 significance level. Conclusion: We concluded that the B-Con course was valued as good for relevance, usefulness, applicability, and satisfaction by the majority of the studied population. Level of Evidence: Level III

Self-consistent numerical dispersion relation of the ablative Rayleigh-Taylor instability of double ablation fronts in inertial confinement fusion

The linear stability analysis of accelerated double ablation fronts is carried out numerically with a self-consistent approach. Accurate hydrodynamic profiles are taken into account in the theoretical model by means of a fitting parameters method using 1D simulation results. Numerical dispersión relation is compared to an analytical sharp boundary model [Yan˜ez et al., Phys. Plasmas 18, 052701 (2011)] showing an excellent agreement for the radiation dominated regime of very steep ablation fronts, and the stabilization due to smooth profiles. 2D simulations are presented to validate the numerical self-consistent theory

Caracterización de tamaños de partícula: comparación entre difracción laser (ld) y microscopía electrónica de barrido (sem)

Two of the most significant properties of particles are size and shape; they often have direct influence on the materials behavior. Since the particulate systems are constituted by 3D particles of different size, the characterization of this property has to be given by a particle size distribution (PSD) . Among the most popular techniques for PSDs measurement, the image analysis (IA) presents some disadvantages: sampling errors, the analysis of only hundred or a few thousand particles to represent the whole population, the use a 2-D projected image of a 3-D particle and long analysis times. In contrast, the laser diffraction technique allows fast particulate systems characterization, processes a high number of particles per assay and provides highly reproducible results. However, LD provides no details about the particle morphology. Both techniques can be considered complementary, however several data interpretation problems appear whe n the results are compared. To do so, it is necessary to understand the meaning of the size descriptors given by each technique and under which conditions the comparison of results from different size analyzers can be done. In this sense, this work explores first the number of particles required to obtain reproducible PSDs by SEM. Then, it presents a comprehensive characterization of PVC particles by assessing a set of size and shape descriptors. The PSDs obtained by IA-SEM and LD were mathematically transformed to be compared. Finally, IA-SEM data was used to evaluate the convenience of using more than one size descriptor to represent the particles volume.Fil: Hegel, C.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Planta Piloto de Ingeniería Química (i); ArgentinaFil: Jones, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahia Blanca; ArgentinaFil: Cabrera, Fernanda Anabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Planta Piloto de Ingeniería Química (i); ArgentinaFil: Yañez, Maria Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahia Blanca; ArgentinaFil: Bucala, Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Planta Piloto de Ingeniería Química (i); Argentin

Comparative pan-genome analysis of Piscirickettsia salmonis reveals genomic divergences within genogroups

Indexación: Scopus.Piscirickettsia salmonis is the etiological agent of salmonid rickettsial septicemia, a disease that seriously affects the salmonid industry. Despite efforts to genomically characterize P. salmonis, functional information on the life cycle, pathogenesis mechanisms, diagnosis, treatment, and control of this fish pathogen remain lacking. To address this knowledge gap, the present study conducted an in silico pan-genome analysis of 19 P. salmonis strains from distinct geographic locations and genogroups. Results revealed an expected open pan-genome of 3,463 genes and a core-genome of 1,732 genes. Two marked genogroups were identified, as confirmed by phylogenetic and phylogenomic relationships to the LF-89 and EM-90 reference strains, as well as by assessments of genomic structures. Different structural configurations were found for the six identified copies of the ribosomal operon in the P. salmonis genome, indicating translocation throughout the genetic material. Chromosomal divergences in genomic localization and quantity of genetic cassettes were also found for the Dot/Icm type IVB secretion system. To determine divergences between core-genomes, additional pan-genome descriptions were compiled for the so-termed LF and EM genogroups. Open pan-genomes composed of 2,924 and 2,778 genes and core-genomes composed of 2,170 and 2,228 genes were respectively found for the LF and EM genogroups. The core-genomes were functionally annotated using the Gene Ontology, KEGG, and Virulence Factor databases, revealing the presence of several shared groups of genes related to basic function of intracellular survival and bacterial pathogenesis. Additionally, the specific pan-genomes for the LF and EM genogroups were defined, resulting in the identification of 148 and 273 exclusive proteins, respectively. Notably, specific virulence factors linked to adherence, colonization, invasion factors, and endotoxins were established. The obtained data suggest that these genes could be directly associated with inter-genogroup differences in pathogenesis and host-pathogen interactions, information that could be useful in designing novel strategies for diagnosing and controlling P. salmonis infection. © 2017 Nourdin-Galindo, Sánchez, Molina, Espinoza-Rojas, Oliver, Ruiz, Vargas-Chacoff, Cárcamo, Figueroa, Mancilla, Maracaja-Coutinho and Yañez.https://www.frontiersin.org/articles/10.3389/fcimb.2017.00459/ful

Evaluation of hemodialysis vascular access. Perspective from Mexico

Chronic kidney disease (CKD) has become a global health problem. In 2019, it was related to 2.53% of general global mortality (2.35-2.66%); in the same year, in Latin America, mortality related to CKD reached 5.25% (4.92-5.49%), with an annual increase of 3.37%, proving increased mortality of 102% between 1990 and 2017. A nephrology specialty in Mexico recently fulfilled its first 50 years. Despite being relatively young, nephrologists are interested in “new” sub-specialties of nephrology and learning novel techniques and problem-solving skills. Our group is the first in our country to focus solely and exclusively on comprehensive VA care and we want to position ourselves as the first Mexican interdisciplinary group focused on vascular access (GIMEXAV)

El turismo de naturaleza: opción para el desarrollo socioeconómico y cultural del circuito Cúcuta, Chinácota, Bochalema y Durania en el departamento Norte de Santander, Colombia

The objective of the research was to promote nature tourism as an alternative to the socioeconomic and cultural development under a sustainable perspective, in the area between the towns of Durania, Bochalema and Chinácota, Norte de Santander Department, Republic of Colombia. The research was qualitative and ethnographic method used in interventions in communities with tourism potential of the state.Customs of the inhabitants, the local cuisine, historic sites, recreational areas, crafts and tourist areas in general were observed. Key informant interviews were also intentionally selected. The research results show that the three municipalities studied have high potential to develop nature tourism boom and its positive impact on improving socioeconomic conditions and cultural preservation of communities. These findings andsubsequent socialization in public bodies Department, made the linkage of the Research Group of UDES CIEMPIÉS, home Cúcuta, the Bureau of Ecotourism Norte de Santander and participation in the preparation of the Tourism Development Plan Department, which was included in this study the proposed tourist circuit. Also in the academic, has initiated the formation of a culture of regional tourism among members of the educational community UDES allowing organize fairs, conferences and tours as a way to integrate the academy to the development of the municipalities.El objetivo de la investigación fue promover el turismo de naturaleza como una alternativa para el desarrollo socioeconómico y cultural, bajo una perspectiva sustentable, en la zona comprendida entre los municipios de Durania, Bochalema y Chinácota, Departamento Norte de Santander, República de Colombia. La investigación fue cualitativa y empleó el método etnográfico en las intervenciones realizadas en las comunidades con potencial turístico de la entidad. Se observaron las costumbres de los habitantes, la gastronomía local, los sitios históricos, áreas recreacionales, artesanías y zonas de interés turístico en eneral. También se realizaron entrevistas a informantes claves seleccionados intencionalmente. Los resultados de la investigación evidencian que los tres municipios estudiados poseen altas potencialidades para desarrollarel turismo de naturaleza y su auge impactará positivamente en la mejora de las condiciones socioeconómicas y de preservación cultural de las comunidades. Estos hallazgos, y su posterior socialización en los entes públicos del Departamento, posibilitaron la vinculación del Grupo de Investigación CIEMPIES de la UDES, sede Cúcuta, a la Mesa de Ecoturismo del Norte de Santander y su participación en la elaboración delPlan de Desarrollo Turístico del Departamento, en el cual fue incluido el circuito turístico propuesto en este estudio. Asimismo, en el orden académico, se ha iniciado la formación de una cultura del turismo regional entre los miembros de la comunidad educativa de la UDES lo que ha permitido organizar ferias, congresos y excursiones como una manera de integrar la academia al desarrollo de los municipios