Methodology for the prediction of paroxysmal atrial fibrillation based on heart rate variability feature analysis.

Atrial fibrillation (AF) is the most clinically diagnosed arrhythmia, as its prevalence increases with age, and its initial stage is paroxysmal atrial fibrillation (PAF). This pathology usually triggers hemodynamic disorders that can generate cerebrovascular accidents (CVA), causing morbidity and even death. The aim of this study is to predict the occurrence of PAF episodes in order to take precautions to prevent PAF episodes. The PhysioNet AFPDB prediction database was used to extract 77 heart rate variability (HRV) features using time domain, geometrical analysis, Poincaré plot, nonlinear analysis, detrended fluctuation analysis, autoregressive modeling, fast Fourier transform (FFT), Lomb-Scargle periodogram, wavelet packet transform (WPT) and bispectrum measurements. The number of features was reduced using the near-zero value, correlation, and recursive feature elimination (RFE) methods for time windows of 1, 2, 5, 10, and 30 min. Feature selection was performed using backwards selection, genetic algorithm, analysis of variance (ANOVA), and non-dominated sorting genetic algorithm (NSGA-III) methods, and then random forest, conditional random forest, k-nearest neighbor (KNN), and support vector machine (SVM) classification algorithms were applied and evaluated using 10-fold cross-validation. The proposed method achieved a precision of 93.24% with a 5-minute window and 89.21% with a 2-minute window, improving performance in predicting PAF when compared with similar studies in the literature.

Percepción de los efectos COVID-19 en la educación presencial y a distancia en estudiantes universitarios del Perú / Perception of the COVID-19 effects in face-to-face and distance education in peruvian university students

La pandemia originó muchos cambios debido al distanciamiento social, uno de ellos es en cuanto a las clases virtuales universitarias. Por esto, el objetivo fue validar un instrumento que mida la percepción de los efectos del COVID-19 sobre la educación a distancia en estudiantes universitarios de las ciencias de la salud y otras carreras en el Perú. Se realizó un estudio instrumental y transversal. Participaron miles de estudiantes de ciencias de la salud y de otras carreras que estudiaban a distancia durante la primera ola del Coronavirus. Se diseñó y validó la encuesta sobre la percepción de que tiene de las repercusiones que causó la emergencia sanitaria sobre en la educación presencial y a distancia; además, se validó de forma exploratoria otra escala para medir la percepción de la propagación del coronavirus. El análisis arrojó alta confiabilidad y buena consistencia interna, con adecuados valores del alfa de Cronbach, para el Análisis Factorial Exploratorio (AFE) se empleó la prueba de Bartlett y el coeficiente Kaiser-Meyer-Olkin. Todos los ítems recibieron una evaluación favorable por parte de los expertos (V de Aiken > 0,70); esto con respecto de la relevancia, representatividad y claridad. Se identificó tres factores medios virtuales, su uso y la presencialidad, todos índices de saturación fueron superiores a 0,50. La encuesta demostró ser confiable y representativa, esto sobre todo por haber sido evaluada en estudiantes de los distintos departamentos peruanos; la cual puede servir para evaluar esto en diversas poblaciones semejantes(AU)

The pandemic caused many changes due to social distancing, one of them is in terms of virtual university classes. Therefore, the objective was to validate an instrument that measures the perception of the effects of COVID-19 on distance education in university students of health sciences and other careers in Peru. An instrumental and cross-sectional study was carried out. Thousands of distance learning students from health sciences and other careers participated during the first wave of the Coronavirus. The survey on the perception that it has of the repercussions caused by the health emergency on face-to-face and distance education was designed and validated; in addition, another scale was exploratory to measure the perception of the spread of the coronavirus. The analysis showed high reliability and good internal consistency, with adequate Cronbach's alpha values. For the Exploratory Factor Analysis (EFA), the Bartlett test and the Kaiser-Meyer-Olkin coefficient were used. All the items received a favorable evaluation by the experts (Aiken's V> 0.70); this with respect to relevance, representativeness and clarity. Three virtual average factors were identified, their use and presence, all saturation indices were greater than 0.50. The survey proved to be reliable and representative, this above all because it was evaluated in students from the different Peruvian departments; which can be used to evaluate this in diverse similar populations(AU)

RICHNESS, CELLULOLYTIC ACTIVITY, AND FUNGICIDE SUSCEPTIBILITY OF FUNGI FROM A BIRD BIOLOGICAL COLLECTION / Riqueza, actividad celulolítica y susceptibilidad a fungicidas de hongos de una colección biológica de aves

Biological collections in natural history museums serve important purposes to the scientific community and the general public, however, their value and utility might be diminished by biodeterioration. We studied a biological collection that represents more than sixty years of avifauna sampling of Colombia, the country with the highest bird diversity. An initial inspection of the collection showed that the general appearance of some specimens was compromised by mold-like growth on their surfaces. We aimed at (i) identifying the taxonomic affiliation of these fungi, (ii) evaluating their cellulolytic activity, and (iii) probing chemical agents that could be utilized to control their growth. The most common fungi genera were Aspergillus, Penicillium, Chaetomium, and Trichophyton, most of which can degrade cellulose. Zinc chloride and salicylic acid showed to be effective fungicides. Based on this, we propose some actions to control the fungi-pest in this biological collection of birds.

Las colecciones biológicas en los museos de historia natural juegan un papel importante tanto para la comunidad cientifica como para el público en general. Sin embargo, su valor y utilidad pueden verse afectados por la biodeterioración de sus ejemplares. Se estudio una colección biológica de aves que representa más de sesenta anos de esfuerzo de muestreo de la avifauna del pais más rico en aves. Una inspección inicial mostró que la apariencia general de algunos de los especimenes de la colección se encontraba afectada por hongos. Los objetivos de este estudio fueron (i) identificar la afiliación taxonómica de los hongos, (ii) determinar la actividad celulolítica y (iii) probar agentes químicos que puedan ser utilizados para controlar su desarrollo. Los géneros de hongos más comunes fueron Aspergillus, Penicillium, Chaetomium y Trichophyton, de los cuales la mayoria presentan la capacidad de degradar celulosa. Adicionalmente, el cloruro de zinc y el ácido salicilico actuaron como fungicidas efectivos. De acuerdo con en estos resultados proponemos algunas acciones para controlar la contaminación por hongos en la colección de aves.

[Respiratory symptoms associated with asthma prevalence and air pollution in preschool children]. / Prevalencia de síntomas respiratorios indicativos de asma y asociación con contaminación atmosférica en preescolares de Bucaramanga, Colombia.

INTRODUCTION: Increases in the air pollution levels has well-documented harmful effects on human health, especially exacerbating problems of asthma and other allergies. OBJECTIVE: The prevalence of symptoms associated with asthma was determined in preschool populations in zones with differing levels of air pollution. MATERIALS AND METHODS: A cross-sectional study was conducted in Bucaramanga, Colombia, comparing respiratory symptoms in 768 children under seven years in two urban zones with different pollution levels of particulate matter and ozone. Morbidity was evaluated for respiratory indicators of asthma by means of a questionnaire version previously validated in Spanish. RESULTS: The use of cigarettes (27.5%) and aerosols (22.7%) were the most frequent source of indoor air pollution. Wheezing prevalence was 25.6% (95% CI 23.2-29.8%) and diagnosis of asthma was 8.4% (95% CI 6.2-11.5%), with no differences between zones. The final multivariate model did not show an association between outdoor pollution and symptoms related with asthma. However, concrete flooring and presence of mold did show an association with these symptoms. CONCLUSIONS: Indoor air quality rather than outdoor air pollution may play a more important role in producing respiratory symptoms related with asthma in preschool children in the city of Bucaramanga, Colombia.

Extracción de paaguicidas en suelo empleando dióxido de carbono supercrítico-cosolventes / Extracton of pessticides in soil using supercritical carbon dioxide -co-solvents / Extracço de pragguicidas em solo utilizndo dióxido de carbono supercriitica- co-solvente

En este estudio se evaluó la eficiencia de tres solventes orgánicos (acetato de etilo, metanol y acetona) empleados como cosolventes en la extracción con fluidos supercríticos (EFS) de una mezcla de plaguicidas con diferentes características fisicoquímicas. Los análisis se realizaron por medio de cromatografía de gases con detección simultánea por microcaptura electrónica (µECD) y nitrógeno-fósforo (NPD) acoplados en paralelo. Se hicieron extracciones a muestras de suelo fortificadas con los plaguicidas empleando dióxido de carbono supercrítico (CO2SC) como fase extractante a 35 °C y 14 MPa adicionando 10 mL de cada cosolvente. Se encontró que el metanol ofrece la mayor eficiencia en el proceso de extracción obteniendo valores de recuperación entre 51,24 y 123,50%.

In this study, three organic solvents (ethyl acetate, methanol and acetone) were used as cosolvent in supercritical fluid extraction (SFE) of a mixture of pesticides with different physical and chemical properties present in soil. These pesticides were determined by gas chromatography with electronic microcapture detector (µECD) and nitrogen-phosphorus detector (NPD), coupled in parallel. The extractions were performed on spiked soil samples using supercritical carbon dioxide (CO2SC) as the extracting phase to 35 °C and 14 MPa, using 10 mL of each cosolvent and it was found that methanol offers the greatest efficiency in the extraction process obtaining recovery values between 51.24 and 123.50%.

No estudo se avaliou três solventes orgânicos (acetato de etila, metanol e acetona), como cosolvente em a extração com fluido supercrítico (EFS) de uma mixtura de praguicidas com diferentes propiedades física e química (organoclorados, or-ganofosforados, organonitrogenados e piretróides) presentes no solo, determinadas por cromatografia gaseosa com in-jecção pulsed splitless e detecção simultânea por µECD e nitrogênio-fósforo (NPD) acoplados em paralelo, as extrações foram realizadas em amostras de solo fortificadas, usando dióxido de carbono (CO2), como a fase de extração a 35 °C 14 MPa, com 10 mL de cada solvente e constatamos que o metanol oferece a maior eficiência da remoção de todos os pragui-cidas e obter recuperação valores entre 51,24 e 123,50%.

Prevalencia de síntomas respiratorios indicativos de asma y asociación con contaminación atmosférica en preescolares de Bucaramanga, Colombia / Respiratory symptoms associated with asthma prevalence and air pollution in preschool children

Introducción. Actualmente se sabe que el incremento de los niveles de contaminación atmosférica externa e interna se asocia con efectos nocivos para la salud, especialmente asma y otras alergias. Objetivos. Determinar la prevalencia de síntomas respiratorios indicativos de asma en la población preescolar y compararla entre zonas con diferentes niveles de contaminación atmosférica en Bucaramanga, Colombia.Materiales y métodos. Estudio observacional analítico de corte transversal que compara los síntomas respiratorios en menores de siete años de dos zonas de la ciudad con niveles diferentes de contaminación por material sólido en partículas y ozono. La morbilidad fue medida con un cuestionario sobre síntomas respiratorios indicativos de asma, validado al español. Resultados. Se estudiaron 768 niños distribuidos de las zonas de alta y baja contaminación. El uso de cigarrillos (27,5%) y aerosoles (22,7%) se encontraron como las fuentes de contaminación más frecuentes dentro de las viviendas. La prevalencia de ruidos respiratorios a lo largo de la vida fue de 25,6% (IC95% 23,2-29,8) y la de diagnóstico médico de asma fue de 8,4% (IC95% 6,2-11,5), sin diferencias significativas entre las zonas. El modelo final no mostró asociación entre la contaminación atmosférica y la presencia de síntomas respiratorios indicativos de asma. Por el contrario, la presencia de pisos de cemento y moho mostró una asociación significativa con estos síntomas. Conclusiones. Es posible que en Bucaramanga los factores de contaminación domiciliaria puedan tener un mayor efecto sobre la presencia de síntomas respiratorios indicativos de asma en menores de siete años que los contaminantes externos.

Introduction. Increases in the air pollution levels has well-documented harmful effects on human health, especially exacerbating problems of asthma and other allergies. Objective. The prevalence of symptoms associated with asthma was determined in preschool populations in zones with differing levels of air pollution. Materials and methods. A cross-sectional study was conducted in Bucaramanga, Colombia, comparing respiratory symptoms in 768 children under seven years in two urban zones with different pollution levels of particulate matter and ozone. Morbidity was evaluated for respiratory indicators of asthma by means of a questionnaire version previously validated in Spanish. Results. The use of cigarettes (27.5%) and aerosols (22.7%) were the most frequent source of indoor air pollution. Wheezing prevalence was 25.6% (95% CI 23.2-29.8%) and diagnosis of asthma was 8.4% (95% CI 6.2-11.5%), with no differences between zones. The final multivariate model did not show an association between outdoor pollution and symptoms related with asthma. However, concrete flooring and presence of mold did show an association with these symptoms. Conclusions. Indoor air quality rather than outdoor air pollution may play a more important role in producing respiratory symptoms related with asthma in preschool children in the city of Bucaramanga, Colombia.

La tierra nuestra de cada día / The land of our everyday

El texto plantea los conflictos agrarios que se han constituido en uno de los principales retos para la estabilidad social y política en Bolivia, situación que afecta las posibilidades de un desarrollo agropecuario y rural vigoroso con el propósito de abatir la pobreza rural, generando un proceso de transformación productiva del agro

IgE and non-IgE food allergy.

BACKGROUND: Food allergy (FA) is characterized by an abnormal immunologic reactivity to food proteins. The gastro-intestinal tract serves not only a nutritive function but also is a major immunologic organ. Although previously thought to be triggered primarily by an IgE-mediated mechanism of injury, considerable evidence now suggests that non-IgE mechanisms may also be involved in the pathogenesis of FA. OBJECTIVE: To review the immunologic disturbances that occur in FA and to correlate these with the clinical manifestations expressed in affected target organs based upon a classification of IgE and non-IgE mechanisms. METHODS: Data collected from a computerized MEDLINE search were used for the analysis of the following topics: immediate GI hypersensitivity, oral allergy syndrome, acute urticaria and angioedema, acute bronchospasm, celiac disease, cow's milk enteropathy, dietary protein enterocolitis, breast milk colitis, proctolitis, proctitis, dermatitis herpetiformis, Heiner syndrome, eosinophilic gastroenteritis, atopic dermatitis, asthma, attention-deficit-hyperactivity disorder and behavioral disorders, as well as systems affected by mucosal associated lymphoid tissue-mediated injury of associated lymphoid tissues and the immunologic deviation to Th1 or Th2 mechanisms of FA. CONCLUSIONS: The results of this review allow the construction of a central, unifying hypothesis for a new classification of FA as follows: the clinical manifestations of FA, expressed in affected target organs, may be the result of immunologic injury mediated by interaction of food antigens with contiguous elements of mucosal associated lymphoid tissue. These appear to be modulated by relative imbalances of the Th1/Th2 paradigm, which may be the ultimate determinant governing the expression of FA as IgE-mediated, non--IgE-mediated, or mixed forms of IgE/non-IgE mechanisms of FA.

De la Reforma Agraria a la guerra por la tierra?

En el presente artículo, se muestran las virtudes y las limitaciones de las políticas públicas agrícolas desde la Reforma Agraria, pero con una tención especial al trabajo efectuado desde la promulgación de la Ley INRA, durante la primera gestión de Sánchez de Lozada