77 research outputs found
Hyperthermophily and the origin and earliest evolution of life
The possibility of a high-temperature origin of life has gained support based on indirect evidence of a hot, early Earth and on the basal position of hyperthermophilic organisms in rRNA-based phylogenies. However, although the availability of more than 80 completely sequenced cellular genomes has led to the identification of hyperthermophilic-specific traits, such as a trend towards smaller genomes, reduced proteinencoding gene sizes, and glutamic-acid-rich simple sequences, none of these characteristics are in themselves an indication of primitiveness. There is no geological evidence for the physical setting in which life arose, but current models suggest that the Earth’s surface cooled down rapidly. Moreover, at 100°C the half-lives of several organic compounds, including ribose, nucleobases, and amino acids, which are generally thought to have been essential for the emergence of the first living systems, are too short to allow for their accumulation in the prebiotic environment. Accordingly, if hyperthermophily is not truly primordial, then heat-loving lifestyles may be relics of a secondary adaptation that evolved after the origin of life, and before or soon after separation of the major lineages
Analysis of the effect of El Niño and La Niña on Tecocomulco Lake, central basin, Mexico
Tecocomulco Lake is a relic of the great basin of the central plateau of Mexico. Its surface area changes in response to both the variation in the inputs from inland areas and the effects of the climatic phenomena of El Niño and La Niña. It is endorreic, with a low rainfall and a low and intermittent fluvial input, a high evaporation, and a considerable influx of sediment due to deforestation and a bad management of the basin. The most important plant species is Schoenoplectus californicus that grows massively in muddy areas, decreasing the depth and reducing the flooded area. The lake is visited by birds from USA and Canada, that arrive to nest and reproduce. During the extremely dry years that coincide with the El Niño, approximately 9% of the dry surface is used by the local inhabitants as cropland, which generates a social problem during the extremely rainy years that coincide with the La Niña when the lake area increases and floods the cultivated land. In the 2001-2002 El Niño, the surface of Tecocomulco Lake decreased by 37% and the depth was 0.75-1 m. This may be associated with a higher temperature, and in consequence a high evaporation, a situation that requires corroboration through future studies
MOLA HIDATIDIFORME PARCIAL CON FETO VIVO DEL SEGUNDO TRIMESTRE
La mola hidatidiforme es un embarazo que se caracteriza por una degeneración hidrópica de las vellosidades coriales y habitualmente la ausencia del feto. La mola parcial se caracteriza por ser resultado de una triploidía diándrica y por la presencia de cambios hidatiformes progresivos lentos con capilares vellosos funcionantes, que afectan solamente a algunas de las vellosidades; se asocia con un feto o embrión anormal identifcable (vivo o muerto), membranas o eritrocitos fetales. Se analiza un caso de mola parcial con feto de 18 semanas
Aplicación de análisis de componente principal en sistemas eléctricos de potencia
El análisis de componente principal (ACP) es una técnica estadística de análisis multivariable ampliamente utilizada para encontrar patrones de datos de alta dimensión. La ventaja fundamental de ACP es la reducción del número de dimensiones de los datos, sin que exista mucha pérdida de información. En este artículo se hace una descripción de esta transformación matemática, y se presentan dos aplicaciones en el área de los sistemas eléctricos de potencia.
ABSTRACT
A common method from statistics for analyzing data is principal component analysis (PCA). The purpose of PCA is to identify the dependence structure behind a multivariable stochastic observation in order to obtain a compact description of it. The paper describes the mathematical fundamentals of PCA and two applications in power system area
Ultrabiomicroscopic-Histopathologic Correlations in Individuals with Autosomal Dominant Congenital Microcoria: Three-Generation Family Report
Background: Congenital microcoria (CMC) is due to a maldevelopment of the dilator pupillae muscle of the iris, with a pupil diameter of less than 2 mm. It is associated with juvenile open angle glaucoma and myopia. We report on a three-generation Mexican-Mestizo family with CMC. The eldest member’s iris biopsy proved muscle anomalies. Further, we analyzed novel ultrasound biomicroscopy findings in the family members who did not require surgery. Patients and Methods: A 62-year-old woman, her 41-year-old son and her 9-year-old grandson affected with microcoria since birth, documented by clinical examination and ultrasound biomicroscopy. The eldest member underwent phacoemulsification, and a biopsy of the iris and the anterior capsule of the lens was taken. Results: Ultrasound biomicroscopy confirmed the CMC diagnosis showing iris thinning and a pupil diameter of less than 2 mm. Histopathology of the iris showed a significant reduction of smooth muscle cells, but no alterations of the anterior lens capsule. Discussion: Although CMC is a rare disorder, which is due to a maldevelopment of the dilator pupillae muscle of the iris, it could be associated with juvenile open angle glaucoma and myopia; therefore, precise diagnosis is required. Ultrasound biomicroscopy could be a great option to confirm the disorder
The Importance of Autophagy and Proteostasis in Metabolic Cardiomyopathy
Metabolic cardiomyopathy and other heart disorders are associated with proteostasis derailment and subsequent autophagy. Proteostasis is a process of protein homeostasis, and autophagy is a mechanism of self-degradation for surviving cells facing stressful conditions. Metabolic challenges have been linked to excess reactive oxygen species. Cardiomyocyte proteotoxicity, an important underlying pathologic mechanism in cardiac disease, is characterized by chronic accumulation of misfolded or unfolded proteins that can lead to proteotoxic formation or aggregation of soluble peptides. Autophagic processes are mediated by the ubiquitin-proteasome and autophagy-lysosome systems, fundamental for cardiac adaptation to physiological and pathological stress. Cellular proteostasis alterations in cardiomyopathy are represented by myocardial remodeling and interstitial fibrosis with reduced diastolic function and arrhythmias. Autophagy regulation may be a potential therapeutic strategy for metabolic cardiomyopathy necessary for the treatment of fibrosis and cardiac tissue remodeling alterations. Furthermore, autophagy has been shown to be active in the perimeter of cardiovascular fibrotic tissue as mechanism of fibrosis recovery and scarring secondary to cell apoptosis. In the present work, we review the current knowledge on the role of autophagy and proteostasis in the pathogenesis of heart failure to resolve the ever-expanding epidemic of metabolic cardiomyopathy and heart failure associated with substantial morbidity and mortality
Relación entre actividad física y obesidad en escolares de primaria del norte de México
The objective of this study was to analyze the relationship between levels of physical activity and obesity in elementary school students belonging to a state public school in the city of Chihuahua, Mexico. A descriptive, correlational and cross-sectional study was carried out, a sample was selected for convenience, 326 schoolchildren of 9.1 ± 2 years of age (178 girls and 148 boys). The levels of Physical Activity (PA) were estimated through an interview, using the "The Godin-Shephard Leisure-Time Physical Activity Questionnaire" (GSLTPAQQ) and to identify obesity the Body Mass Index (BMI) and the Waist Circumference (WC). The statistical analysis showed us negative bilateral Pearson correlations with significance between vigorous PA and BMI (r = -. 139, p≤0.050), as well as between WC (r = -. 150, p≤0.010). In addition, schoolchildren with obesity showed that they perform significantly less vigorous PA per week, when compared to those who are overweight (p≤0.050), and those with normal weight (p≤0.010). The results indicate that the majority of the schoolchildren with higher BMI and WC significantly perform less vigorous PA. Similarly, we can establish that schoolchildren with obesity significantly perform less vigorous PA per week. Therefore, it is necessary to promote vigorous physical activities inside and outside of school in this type of population, in order to prevent obesity.El objetivo del presente estudio fue analizar la relación entre los niveles de actividad física y obesidad en escolares de primaria pertenecientes a una escuela pública estatal de la ciudad de Chihuahua, México. Se realizó un estudio descriptivo, correlacional y transversal, se seleccionó una muestra por conveniencia, 326 escolares de 9.1±2 años de edad (178 niñas y 148 niños). Los niveles de Actividad Física (AF) fueron estimados mediante una entrevista, utilizando el “The Godin-Shephard Leisure-Time Physical Activity Questionnaire” (GSGSLTPAQQ) y para identificar la obesidad se utilizó el Índice de Masa Corporal (IMC) y la Circunferencia de Cintura (CC). El análisis estadístico nos mostró correlaciones bilaterales de Pearson negativas con significancia entre la AF vigorosa y el IMC (r=-.139, p≤0.050), así como entre la CC (r=-.150, p≤0.010). Además los escolares con obesidad mostraron que realizan significativamente menos AF vigorosa por semana, al compararlos vs los que presentan sobrepeso (p≤0.050), y los que presentan normo peso (p≤0.010). Los resultados nos indican que la mayoría de los escolares que presentan mayor IMC y CC realizan menos AF vigorosa de forma significativa. De igual forma podemos establecer, que los escolares con obesidad realizan menos AF vigorosa por semana de forma significativa. Por lo que es necesario que se promuevan actividades físicas vigorosas dentro y fuera de la escuela en este tipo de poblaciones, con el fin de prevenir la obesidad. 
Composteo de un suelo contaminado con hidrocarburos fracción pesada con cáscara de naranja y gallinaza como cosustratos
Se estudió el composteo de un suelo contaminado con hidrocarburos fracción pesada (HFP), empleando dos cosustratos, cáscara de naranja y gallinaza. Se caracterizó el suelo, con 11698 mg HFP/kg. El composteo se llevó a cabo durante ocho semanas. Además, en un experimento de bioestimulación, se adicionaron nutrientes inorgánicos para alcanzar la relación C: N: P igual a 100:15:1. Se observó una eficiencia de degradación de HFP de 57.63% para la composta de cáscara de naranja y de 37.53% para la composta de gallinaza. Estas eficiencias no mejoraron en el experimento de bioestimulación. La concentración final alcanzada de 5829.7 mg HFP /kg para la composta con cáscara de naranja superó el límite máximo permisible (6000 kg/kg) para un suelo de uso industrial señalado en la NOM-138- SEMARNAT/SSA1-2012 en un plazo de ocho semanas. Esto coincide con el incremento del conteo bacteriano final de la composta.We studied the composting process of heavy fraction hydrocarbon (HFH) contaminated soil, using two co-substrates, orange peel and chicken manure. Soil was characterized with 11698 mg HFP/kg. It was composted for eight weeks. In addition, in an experiment of biostimulation, inorganic nutrients were added to achieve the C: N: P ratio equal to 100:15:1. A degradation efficiency of 57.63 %of HFP for orange peel compost and 37.53 %s for compost of chicken manure were observed. These efficiencies did not improve in the biostimulation experiment. The final concentration of 5829.7 HFP mg/kg for the orange peel compost exceeded the maximum permissible limit (6000 kg/kg) for a soil for industrial us, indicated in the NOM-138-SEMARNAT/SSA1-2012, in only eight weeks. This coincides with the increase of final bacterial counts of the compost
Perfil Fisiológico y Rendimiento Deportivo en Jugadoras de Baloncesto Universitario
Propósito: identificar diferencias en capacidades físicas y tiro libre en jugadoras de baloncesto universitario por posición de juego. Método: quince jugadoras de baloncesto representativas de la Universidad Autónoma de Chihuahua, edad 21.7 (± 2.5) años, peso 70.7 (8.6) kg, altura 170 (7.5) cm y la experiencia de baloncesto de 10.0 (3.6) años se dividieron de acuerdo con su posición de juego en grupos de Point Guard (PG) (n = 6), Forward (PF) (n = 5) y Center (C) (n = 4). El perfil físico específico del baloncesto incluyó la capacidad aeróbica estimada con la Prueba de recuperación intermitente YoYo, agilidad (prueba de agilidad de baloncesto), velocidad (prueba de velocidad de cancha 3/4), salto vertical (contramovimiento vertical prueba de salto), determinación de porcentaje de tiro libre estático y dinámico. No se detectaron diferencias significativas en las comparaciones entre grupos en ninguna de las variables, lo cual no es de esperarse debido a que se ha reportado que los jugadores PG tienden a ser más veloces, ágiles y con mayor potencia en piernas que los centros, evidenciando el bajo nivel de los PG, mismos que presentaron un IMC con sobrepeso. Conclusión: se encontraron valores homogéneos entre los grupos, lo que no es representativo de la literatura en la que PG y PF presentan mejor estado físico.
Purpose: to identify differences in physical abilities and free throw shoot in college basketball players by playing position. Method: fifteen representative basketball players from the Autonomous University of Chihuahua, age 21.7 (± 2.5) years, weight 70.7 (8.6) kg, height 170 (7.5) cm and basketball experience of 10.0 (3.6) years were divided according with their playing position in groups of Point Guard (PG) (n = 6), Forward (PF) (n = 5) and Center (C) (n = 4). Basketball specific physical profile included aerobic capacity estimated with the YoYo Intermittent Recovery Test, agility (basketball agility test), speed (3/4 court speed test), vertical jump (vertical countermovement jump test), Determination of percentage of static and dynamic free kick. No significant differences were detected in the comparisons between groups in any of the variables, which is not to be expected because it has been reported that PG players tend to be faster, more agile and with more power in the legs than the centers, evidencing the low level of the GPs, who presented an overweight BMI. Conclusion: homogeneous values were found between the groups, which is not representative of the literature in which PG and PF present better physical condition
Cinética de fitoextracción de arsénico y cadmio mediante Myriophyllum aquaticum y Wolffia columbiana
Se estudió la cinética de fitoextracción de arsénico y cadmio, en plantas acuáticas Myriophyllum aquaticum (Vell.) Verdc. y Wolffia columbiana Karsten expuestas a cuatro muestras de agua, con concentraciones de 0.49, 0.82, 1.43 y 2.42 mg/L de arsénico y 0.16, 0.26, 0.99 y 2.05 mg/L de cadmio. Se obtuvieron los parámetros del modelo de Michaelis-Menten, destacando la velocidad máxima de remoción para M. aquaticum (0.049 mg As kg-1 h-1; 0.616 mg Cd kg-1 h-1) y W. columbiana (0.273 mg As
kg-1 h-1; 1428 mg Cd kg-1 h-1), necesarios para predecir el tiempo y la velocidad para restaurar cuerpos de agua. De acuerdo con el factor de bioconcentración ambas especies son hiperacumuladoras de cadmio y acumuladoras de arsénico. W. columbiana concentró arsénico cuatro veces más que M. aquaticum. W. columbiana logró concentrar tres veces más cadmio que arsénico, mientras que M. aquaticum extrajo más de 35 veces cadmio que arsénico.The kinetics of phytoextraction of arsenic and cadmium were studied in Myriophyllum aquaticum (Vell.) Verdc. and Wolffia columbiana Karsten aquatic plants, exposed to four water samples with concentrations of 0.49, 0.82, 1.43, 2.42 mg/L of arsenic and 0.16, 0.26, 0.99, 2.05 mg/L of cadmium. The parameters of the Michaelis-Menten model were obtained, standing out the maximum removal rate for M. aquaticum (0.049 mg As kg-1 h-1; 0.616 mg Cd kg-1 h-1) and W. columbiana (0.273 mg As kg-1 h-1; 1428 mg Cd kg-1 h-1), necessary to predict to rate the time and speed to restore bodies of water. According to the bioconcentration factor both species are hyperaccumulative for cadmium and they are arsenic accumulators. W. columbiana concentrated arsenic four times more than M. aquaticum. W. columbiana managed to concentrate three times more cadmium than arsenic, while M. aquaticum extracted
35 more times cadmium than arsenic
- …