333 research outputs found
Hydrochemistry of northwest Spain ponds and its relationships to groundwaters
We built a classification system for lentic ecosystems and groundwaters in South-East León based on degree of mineralization and composition of major ions. In the ponds with the softest water (< 5 mEq/L), chlorides and bicarbonates were the main mineralizing anions. In contrast, in more highly mineralized ponds (> 5 mEq/L), all major ions were at comparable proportions. In these more mineralized shallow lakes, more sulphates could be found compared to less mineralized waters in the region. Independently of the level of mineralization, calcium was the predominant cation, although shallow lakes with lower mineral content favoured sodium over magnesium. The intense summer evaporation and the filling in autumn of ponds which had completely dried out and remained dry during the summer triggered changes not only in the mineral content, but also in the ionic composition of the water, with an increase in the concentrations of all ions in autumn. Overall mineralization and alkalinization were the two chief factors shaping the chemical variability of groundwater in our region. The length of flows discharging into groundwater-influenced areas shaped the general features of the wetlands studied, so that the degree of mineralization of the water in any given lake was determined in large measure by the geographical position. Thus, the greater length of flows in southerly areas of the study zone led to an increase in the more highly mineralized shallow lakes of the salinity of groundwater and of surfacing groundwater. Nonetheless, a substantial number of the ponds investigated are apparently linked to the aquifers under the "raña" formations. The chemical make-up of the water in these bodies is to some extent related to precipitation in the form of rain or in other forms and is apparently little influenced by groundwater. Hence the ponds are made up of slightly mineralized sheets of water, and can be tracked to discharges from brief surfacing groundwater flows. A link to deeper regional flows can be identified by the presence of comparatively more mineralized water bodies. Overall, outflows do not correspond to the chemical pattern of groundwaters, suggesting a more complex explanation for the hydrology of the study area.Se realizó una tipificación de los sistemas leníticos y del agua subterránea en el sureste de la provincia de León basada en su grado de mineralización y composicón iónica mayoritaria. En las lagunas más dulces (<5 mEq/L) cloruro y bicarbonato fueron los aniones con mayor peso en la mineralización. Por el contrario, en las lagunas más mineralizadas (>5 mEq/L) las proporciones de los aniones mayoritarios fueron muy semejantes, con un incremento de sulfato respecto a las aguas menos mineralizadas. Con independencia del nivel de mineralización, el calcio fue el catión predominante, aunque la disminución del contenido mineral favoreció al sodio sobre el magnesio. La intensa evaporación producida durante el verano y el llenado en otoño de las lagunas que permanecieron secas en el periodo anterior provocaron cambios no sólo en el contenido mineral, sino también en la composición iónica del agua, con aumento de las concentraciones de todos los iones en otoño. La mineralización global y la alcalinización fueron los dos procesos más importantes que marcaron la varibilidad hidroquímica del agua subterránea. La longitud del flujo de descarga en las áreas bajo la influencia del agua subterránea ha condicionado las características de los humedales estudiados, de modo que el nivel de mineralización del agua ha estado determinado en buena medida por su posición geográfica. Es así que el aumento de la longitud de flujo hacia el sur del área de estudio ha determinado un incremento de la concentración salina del agua subterránea y de su manifestación en superficie, en formaciones palustres más mineralizadas. No obstante, una parte importante de las lagunas estudiadas aparecen ligadas a los acuíferos de rañas y el carácter hidroquímico de sus aguas está relacionado, en parte, con el agua meteórica y aparece poco influenciado por el agua subterránea. Constituyen, por tanto, láminas de agua poco mineralizada, identíficándose como descargas de flujos subterráneos cortos. La conexión con flujos regionales más profundos se reconocen como lagunas que comparativamente son altamente mineralizadas. Sin embargo, estas descargas no tienen correspondencia con el quimismo de las aguas subterráneas, lo que otorga una cierta complejidad al comportamiento hidrológico observado en el área de estudio
A composite indicator of urban quality of life : an application to European cities
La mejora de la calidad de vida urbana se ha convertido en uno de los principales retos a los que se enfrentan las ciudades actualmente, no solo porque la aglomeración de personas hace que su calidad de vida sea más propensa a ser deteriorada, sino porque en un contexto de globalización creciente las ciudades deben competir cada vez en mayor medida por atraer capital físico y humano. Así, la calidad de vida es un factor importante en las decisiones de localización de personas y empresas.
Los esfuerzos por mejorar el nivel de calidad de vida urbana requieren de su evaluación previa, lo cual no es una tarea fácil por tratarse de un fenómeno multidimensional y abstracto. Adicionalmente, la subjetividad implícita en este concepto posibilita que cada ciudad pueda otorgar una importancia diferente a las distintas dimensiones que lo integran. Se hace necesario por tanto que dicha subjetividad sea conservada. El presente artículo propone un indicador sintético aplicable a contextos urbanos europeos que permita aproximar la calidad de vida que ofrecen las ciudades, respetando las distintas formas que tienen de alcanzarla.The improvement of liveability has become one of the main challenges that cities face today. This is not only necessary because the excessive concentration of people in urban areas constitutes a threat to the urban quality of life, but also cities are increasingly forced to compete by attracting physical and human capital. In this sense, the quality of life is a factor that plays an important role in location decisions of both individuals and companies.
These efforts to improve the existing level of quality of life in cities require a prior assessment, which is not an easy task because this is a multidimensional phenomenon that involves a high degree of abstraction. An added difficulty is the subjectivity inherent in this concept, which means that each city will be giving a different weight to the different aspects that make it up. Therefore, it is desirable to preserve this subjectivity. In this article, we propose a composite indicator to assess the urban quality of life offered by different European cities, preserving the different ways they might have to reach it.Fil: Valcárcel Aguiar, Beatriz.
Universidad de Santiago de Compostela. Departamento de Economía CuantitativaFil: Murias Fernández, Pilar.
Universidad de Santiago de Compostela. Departamento de Economía CuantitativaFil: De Miguel Domínguez, José Carlos.
Universidad de Santiago de Compostela. Departamento de Economía Cuantitativ
Sexualidad en embarazo y postparto: la necesidad de educación afectivo-sexual
El estudio de la sexualidad femenina durante el embarazo y tras el parto ha sido infravalorado hasta la fecha. Sin embargo, son numerosos los factores biopsicosocioculturales asociados a estos acontecimientos que influyen en la vivencia de la sexualidad, la intimidad y el placer de las mujeres, y la de sus parejas. Por ello, por medio del presente trabajo se pretende visibilizar dichas condiciones especiales de la maternidad y poner en valor la educación afectivo-sexual como estrategia de acompañamiento a estos desafíos vitales.
A strain of Bacillus thuringiensis containing a novel cry7Aa2 gene that is toxic to Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae)
The genome of the Bacillus thuringiensis BM311.1 strain was sequenced and assembled in 359 contigs containing a total of 6,390,221 bp. The plasmidic ORF of a putative cry gene from this strain was identified as a potential novel Cry protein of 1138 amino acid residues with a 98% identity compared to Cry7Aa1 and a predicted molecular mass of 129.4 kDa. The primary structure of Cry7Aa2, which had eight conserved blocks and the classical structure of three domains, differed in 28 amino acid residues from that of Cry7Aa1. The cry7Aa2 gene was amplified by PCR and then expressed in the acrystalliferous strain BMB171. SDS-PAGE analysis confirmed the predicted molecular mass for the Cry7Aa2 protein and revealed that after in vitro trypsin incubation, the protein was degraded to a toxin of 62 kDa. However, when treated with digestive fluids from Leptinotarsa decemlineata larvae, one major proteinase-resistant fragment of slightly smaller size was produced. The spore and crystal mixture produced by the wild-type BM311.1 strain against L. decemlineata neonate larvae resulted in a LC50 value of 18.8 mu g/mL, which was statistically similar to the estimated LC50 of 20.8 mu g/mL for the recombinant BMB17-Cry7Aa2 strain. In addition, when this novel toxin was activated in vitro with commercial trypsin, the LC50 value was reduced 3.8-fold to LC50 = 4.9 mu g/mL. The potential advantages of Cry7Aa2 protoxin compared to Cry7Aa1 protoxin when used in the control of insect pests are discussed.This research was funded by the Programa Nacional de España (No. AGL2015-70584-C2-2-R) and the Gobierno de Navarra (No. IIQ14065: RI1)
L-arginine ameliorates defective autophagy in GM2 gangliosidoses by mTOR modulation
Aims: Tay–Sachs and Sandhoff diseases (GM2 gangliosidosis) are autosomal recessive disorders of lysosomal function that cause progressive neurodegeneration in infants and young children. Impaired hydrolysis catalysed by β-hexosaminidase A (HexA) leads to the accumulation of GM2 ganglioside in neuronal lysosomes. Despite the storage phenotype, the role of autophagy and its regulation by mTOR has yet to be explored in the neuropathogenesis. Accordingly, we investigated the effects on autophagy and lysosomal integrity using skin fibroblasts obtained from patients with Tay–Sachs and Sandhoff diseases. Results: Pathological autophagosomes with impaired autophagic flux, an abnormality confirmed by electron microscopy and biochemical studies revealing the accelerated release of mature cathepsins and HexA into the cytosol, indicating increased lysosomal permeability. GM2 fibroblasts showed diminished mTOR signalling with reduced basal mTOR activity. Accordingly, provision of a positive nutrient signal by L-arginine supplementation partially restored mTOR activity and ameliorated the cytopathological abnormalities. Innovation: Our data provide a novel molecular mechanism underlying GM2 gangliosidosis. Impaired autophagy caused by insufficient lysosomal function might represent a new therapeutic target for these diseases. Conclusions: We contend that the expression of autophagy/lysosome/mTOR-associated molecules may prove useful peripheral biomarkers for facile monitoring of treatment of GM2 gangliosidosis and neurodegenerative disorders that affect the lysosomal function and disrupt autophagy
Effect of Oxytocin, Cloprostenol or Buserelin in Semen Doses on Sow Fertility
[EN] During the periods January to April, May to August, and September to December in two consecutive years, sows were assigned at breeding to receive semen doses supplemented with 87 µg cloprostenol (PG; n = 158), 5 IU oxytocin (OT; n = 154), 2 µg buserelin (GN; n = 93), or served as non-supplemented controls (CON; n = 605). Sows were inseminated at the detection of estrus, and again 24 h later, but only the first inseminations were supplemented. Compared to CON, only buserelin increased pregnancy and farrowing rates (p ≤ 0.05); there was no effect of a period or a treatment × period interaction. Litter size was larger (p ≤ 0.001) for all seminal additive groups during the first two periods and tended to increase in GN compared to CON (p ≤ 0.1) during the third period, resulting in a tendency (p < 0.1) for a period × treatment interaction. The addition of cloprostenol, oxytocin or buserelin to semen doses at first insemination increases litter size in multiparous sows.SIThis research received no external fundin
Enzymatic fine-tuning for 2-(6-hydroxynaphthyl) β-d-xylopyranoside synthesis catalyzed by the recombinant β-xylosidase BxTW1 from Talaromyces amestolkiae
This article is distributed under the terms of the Creative Commons Attribution 4.0 International License.-- et al.[Background]: Glycosides are compounds displaying crucial biological roles and plenty of applications. Traditionally, these molecules have been chemically obtained, but its efficient production is limited by the lack of regio- and stereo-selectivity of the chemical synthesis. As an interesting alternative, glycosidases are able to catalyze the formation of glycosides in a process considered green and highly selective. In this study, we report the expression and characterization of a fungal ß-xylosidase in Pichia pastoris. The transglycosylation potential of the enzyme was evaluated and its applicability in the synthesis of a selective anti-proliferative compound demonstrated. [Results]: The ß-xylosidase BxTW1 from the ascomycete fungus Talaromyces amestolkiae was cloned and expressed in Pichia pastoris GS115. The yeast secreted 8 U/mL of ß-xylosidase that was purified by a single step of cation-exchange chromatography. rBxTW1 in its active form is an N-glycosylated dimer of about 200 kDa. The enzyme was biochemically characterized displaying a K m and k cat against p-nitrophenyl-ß-d-xylopyranoside of 0.20 mM and 69.3 s¿1 respectively, and its maximal activity was achieved at pH 3 and 60 °C. The glycan component of rBxTW1 was also analyzed in order to interpret the observed loss of stability and maximum velocity when compared with the native enzyme. A rapid screening of aglycone specificity was performed, revealing a remarkable high number of potential transxylosylation acceptors for rBxTW1. Based on this analysis, the enzyme was successfully tested in the synthesis of 2-(6-hydroxynaphthyl) ß-d-xylopyranoside, a well-known selective anti-proliferative compound, enzymatically obtained for the first time. The application of response surface methodology, following a Box-Behnken design, enhanced this production by eightfold, fitting the reaction conditions into a multiparametric model. The naphthyl derivative was purified and its identity confirmed by NMR. [Conclusions]: A ß-xylosidase from T. amestolkiae was produced in P. pastoris and purified. The final yields were much higher than those attained for the native protein, although some loss of stability and maximum velocity was observed. rBxTW1 displayed remarkable acceptor versatility in transxylosylation, catalyzing the synthesis of a selective antiproliferative compound, 2-(6-hydroxynaphthyl) ß-d-xylopyranoside. These results evidence the interest of rBxTW1 for transxylosylation of relevant products with biotechnological interest.This work was carried out with funding from projects BIO2015-68387-R, RTC-2014-1777-3 and CTQ2015-64597-C2 from MINECO and S2013/MAE2972
from Comunidad de Madrid, as well as from the Natural Sciences and Engineering Research Council of Canada. M. Nieto-Domínguez thanks the MINECO for an FPU fellowship.We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI).Peer Reviewe
Razonamiento y argumentación en Ciencias. Diferentes puntos de vista en el currículo oficial
Las perspectivas constructivistas del aprendizaje y de la enseñanza de las ciencias señalan la importancia de que los
alumnos aprendan a razonar y a argumentar. Los nuevos currículos de ciencias deberían tener en cuenta el campo de las destrezas
cognitivas y de pensamiento. A ese respecto, hemos diseñado un marco referencial y una clave de vaciado y de categorización de
contenidos procedimentales que nos han permitido evaluar si el currículo oficial de la Argentina fomenta el aprendizaje de las
estrategias de razonamiento y de argumentación en niveles de enseñanza no universitarios y en la formación de profesoresThe constructivist approaches to learning in science teaching show towards the importance of students learning how
to reason an argument. The new science curriculum should contemplate the field of cognitive and thinking skills. To evaluate if the
official curriculum in Argentina promotes reasoning and argumenting strategies at different educational levels and in teacher
education, a reference scheme and a procedure for categorizing methodological content has been designed.S
Valoración crítica del programa de la asignatura anatomía III aplicada al Policlínico Universitario A critical valuation of the Anatomy III subject program applied to the university clinic
La universidad, como institución social es la encargada de formar los recursos humanos para el desarrollo de la sociedad, refleja sus valores y responde a sus intereses, acorde con el momento histórico y el contexto socio cultural. Se realizó una revisión del programa de la asignatura Anatomía III, con el objetivo de valorar su diseño en cuanto a contenidos y habilidades, así como su pertinencia y calidad. Se analizaron sus objetivos generales, educativos e instructivos, contenidos y distribución de fondo de tiempo, sistema de evaluación, métodos, medios de enseñanza y literatura recomendada. Determinamos que el programa tiene bien diseñados sus objetivos generales instructivos y educativos, pero presenta factores que generan dificultades en el desarrollo del programa como el distanciamiento del perfil del egresado, falta de comprensión por falta del resto del cuerpo académico, y que abordan al sujeto de forma fragmentada. Recomendamos que la propuesta sea valorada en el colectivo de la disciplina, enfatizando la vinculación básico clínica, incorporando las estancias en cada territorio al hacer el examen práctico descentralizado y considerar la esencialidad de los contenidos para la reestructuración del programa. Palabras clave: Evaluación Educacional, Anatomía, Universidades, Estudiantesde Medicina, Escuelas Médicas, Materiales De Enseñanza, Programas. ABSTRACT The University as a social institution is dedicated to create the human resources in order to develop society, reflecting its values and answering for its interests according to the historical moment and the social -cultural context A review of the program of Anatomy III was made with the purpose of validating its design according to the contents and skills as well as its quality. The general educative and instructed objects were analyzed as well as the contents and distribution of the time planned for preparation of the teaching activities, system of evaluation, methods, teaching aids and literature recommended. It is pointed out that the program has instructive educative general objectives well designed, but presents some factors causing difficulties in the development of the program, as the distance from the profile of the graduate, lacking of comprehensiveness by the members of the academic staff and fragmentary way of approaching the individual. It is recommended that the proposal be assessed by the staff,emphasizing the clinical-basic link and adding rotations in every territory, making a decentralized practical examination and considering the essence of contents for the re-structuring of the program. Key words: Educational Evaluation , Anatomy. Universities, Medical Students, Medical Schools, Teaching Aids. Programs
Análisis de la argumentación dialógica generada a partir de un problema auténtico sobre electricidad (análise da argumentação dialógica gerada a partir de um problema autêntico sobre eletricidade)
Desde la perspectiva del aprendizaje de las ciencias como construcción social del conocimiento, se pretende que los estudiantes elaboren argumentos acerca de cuestiones y problemas científicos. Este argumento se lo significa como un argumento situado, existiendo métodos y criterios que permiten su análisis y comparación (Duschl, 1990; Driver y Newton, 1997; Jiménez, 1998). El presente trabajo se realiza en el marco de la investigación de Tesis de Doctorado de la primera de los autores. Su propósito es poner en evidencia qué potencialidad tiene un problema auténtico para promover la argumentación durante una prueba piloto aplicada a una pareja de futuras profesoras de Física y Química. El problema plantea la transformación de la energía eléctrica en una resistencia óhmica y se diseña a partir de una salida integradora del Proyecto AcAb (García-Rodeja et al., 1994). Del análisis de las transcripciones surgen aspectos epistémicos y argumentativos
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