Gender differences in e-learning satisfaction

In line with recent research, the question this paper raises is whether or not gender differences also exist in e-learning. This study is based on a sample of 1,185 students who are doing on-line courses at the Universidad de Granada in Spain. The main conclusion is that female students are more satisfied than male students with the e-learning subjects that make up the sample. Furthermore, we find that female students assign more importance to the planning of learning, as well as to being able to contact the teacher in various ways.: Gender Studies; Evaluation Methodologies

Planta de producción de ácido cianhídrico

Traballo Fin de Grao en Enxeñaría Química. Curso 2016/2017La elección del tema del proyecto proviene tanto de la inexistencia de proyectos académicos relacionados con el ácido cianhídrico como del incremento de la demanda de este producto en la actualidad. La causa principal es la sustitución de diversos componentes mecánicos del automóvil hasta ahora fabricados con aleaciones ferrosas por componentes fabricados con nylon. Este compuesto disminuye la masa de los automóviles y reduce el rozamiento, por lo que minimiza las pérdidas energéticas. En el proceso de fabricación del nylon, se emplea como intermediario el ácido cianhídrico, por lo que el repunte en el sector automovilístico y la búsqueda de nuevos materiales provoca un aumento en la demanda. Otro de los compuestos derivados del ácido cianhídrico empleado en la fabricación de automóviles es el metacrilato, para los recubrimientos de los focos. Además, a partir del ácido cianhídrico se puede producir el aminoácido metionina de forma sintética. Este aminoácido se emplea en el sector primario como suplemento alimenticio para el ganado. Por todas las razones presentadas anteriormente, se considera una alternativa interesante la elección de la temática para elaborar este proyecto básico. En relación a la elección de alternativas, como se presenta en el apartado análisis de alternativas, se siguen criterios económicos, medioambientales y de seguridad.Universidade de Santiago de Compostela. Departamento de Enxeñaría Químic

Aggregation of biological building blocks: a theoretical and spectroscopic study

521 p.DNA and proteins are involved in biological processes which make possible life. On the one hand, the four DNA bases constitute the alphabet of life. Their normal appearance includes stacked Watson-Crick pairs in order to form DNA strands, reinforced by the existence of the sugar backbone. However, the appearance of unusual structures, such as Hoogsteen pairs, triplexes and quadruplexes, raises the question of which are the intrinsic preferences of the DNA aggregation. On the other hand, proteins are chains of amino acids, whose interactions with DNA strands are the basis of the nucleosome formation. The mechanism which guides the nucleosome formation is still bewildering. The first goal of this thesis is the characterization of the non-covalent interactions in biological species and their aggregates by a combination of DFT calculations and Non-Covalent Interaction approach. The second goal is the elaboration of a reductionist model applying theoretical calculations, based in amino acid-DNA base interactions, in order to explain the leading mechanism of the histone-DNA formation. Finally, the third goal is the study of the intrinsic preferences of the DNA base self-aggregation process, analyzing the tautomerical landscape of the DNA bases, focusing on the competition between hydrogen bond and dispersive contributions. A combination of theoretical calculations and spectroscopic techniques has been used to understand the self-aggregation of purines (guanine) and pyrimidines (cytosine) in gas phase

Tin oxide preparation and characterization and use as a catalyst in the reaction of unsaturated fatty esters epoxidation

La síntesis y la caracterización del óxido de estaño se estudiaron en este trabajo para evaluar su actividad catalítica en la reacción de epoxidación del metilricinoleato proveniente del aceite de ricino. La obtención del óxido se realiza por el método de precipitación controlada, encontrándose que se obtienen ventajas significativas al emplear soluciones acuosas de SnCl2.2H2O como precursor. Su caracterización se efectuó por medio de las técnicas de DTA, TGA, DRX, encontrándose que para obtener un alto rendimiento hacia el sistema casiterita el valor de pH óptimo fue de 6.25, mientras que un pH de 8.0 conlleva hacia el sistema romarchita. En el caso de las técnicas de MEB y área superficial, se determinó que el tamaño de partícula encontrado estaba por debajo de los 50 nm con un área superficial de 19 m2/g. El ester ricinoleico se obtuvo a partir del aceite empleando metilato de sodio como catalizador y seguidamente se hace reaccionar con peróxido de hidrógeno como agente oxidante y óxido de estaño para producir un epóxido. Finalmente, los productos de reacción se identifican por cromatografía de gases, encontrando que los óxidos de estaño son activos para la obtención de epóxidos con un mejor desempeño del sistema cristalino romarchita (SnO) principalmente hacia el metil-12-hidroxi-9,10-epoxioctadecanoato (MHEOD). Abstract Tin oxide synthesis and characterization were studied in the present work in order to evaluate its catalytic activity in the reaction of methyl ricinoleate from castor oil. Oxide is obtained through the controlled precipitation method, and significant advantages are obtained when using water solutions of SnCl2.2H2O as precursor. Its characterization was done using the techniques DTA, TGA, XRD, finding that in order to have high performance for the cassiterite system the optimum pH value was 6,25 whereas a pH of 8.0 was leading to the romarchite system. When using SEM techniques and a surface area, the size of the particle found was below 50 nm with a surface area of 19 m2/g. The ricinoleate ester was obtained from the oil using sodium methylate as catalyst and then making it react with hydrogen peroxide as oxidant agent and tin oxide to produce an epoxide. Finally, reaction products are identified through gas chromatography finding that tin oxides are active for obtaining epoxides with better performance of the romarchite crystal system (SnO) especially towards the methyl-12-hydroxi-9, 10-epoxioctadecanote (MHEOD)

Análisis Psicofisiológico de Estímulos Sonoros

Electroencephalography signals (EEG) has captured the general interest of the scientific community; nowadays, the most part of the investigations of the topic are focused on the emotional psychophysiological effect that this kind of signals are able to show according different types of stimuli; therefore, this document shows the analysis of different sets of EEG signals, captured by NeuroSky headset, under the stimulation produced by emotional content sounds from the IADS (International Affective Digital Sounds); furthermore, some EEG signals from the "DREAMER" dataset were also analyzed. From this document was mainly concluded that there was a corresponsive result between subjective and objective data as valence and arousal values were corresponsive with EEG frequency bands; furthermore, for DREAMER set, electrodes of the right hemisphere were the ones with more energy.Las señales de electroencefalografía (EEG) han captado el interés de la comunidad científica; actualmente, la mayoría de las investigaciones están enfocadas a cómo estas señales reflejan la respuesta psicofisiológica de las personas, en términos emocionales, respecto a diferentes estímulos; por esta razón, en este documento se presenta el análisis de señales de EEG captadas por el headset de NeuroSky ante estímulos sonoros con contenido emocional provenientes de la IADS (International Affective Digital Sounds); además, se analizaron algunas señales del dataset de EEG “DREAMER”. De este desarrollo se llegó a que hay una correspondencia entre los valores de Valencia y Arousal con las bandas de frecuencia de EEG, observando además que, para el caso del DREAMER, los electrodos correspondientes al hemisferio derecho presentaban la mayoría de la energía en el cerebro

Correlation Analysis of High-Throughput Fruit Phenomics and Biochemical Profiles in Native Peppers (Capsicum spp.) from the Primary Center of Diversification

[Abstract] The main goal of this work was to investigate the relationship between the fruit morphology and biochemical composition of peppers (Capsicum spp.). For that purpose, one hundred native varieties from the Andean region, where the genus Capsicum has its origin, were analysed for different phytochemical compounds. In addition, pepper fruits were assessed with the highly precise phenomics tool Tomato Analyzer. The collection showed a broad variability which was more evident within the C. annuum group. On average, C. frutescens accessions displayed the highest levels of solid soluble content, pH, polyphenols and antioxidant activity. The Tomato Analyzer descriptors under the categories of size, shape index, and latitudinal section, mostly contributed to the variance among Capsicum groups. C. annuum hold the larger fruits, whereas C. frutescens comprised fruits of smaller sizes. The correlation analysis revealed that biochemical traits were negatively correlated with the fruit parameters related to size, suggesting that huger fruits contain lower amounts of chemical metabolites. The multivariate approximations demonstrated that Andean peppers assorted according to morphometric and colorimetric characteristics, but independently of their species or geographical origin. Groups of valuable native varieties carrying promising traits were identified.Ministerio de Economía y Competitividad; RTA2015-00042-C02-02Xunta de Galicia; ED431C 2018/57This research was funded by Spanish Institute for Agricultural and Food Research and Technology (INIA), co–financed by the European Regional Development Fund (FEDER) (Project RTA2015-00042-C02-02), and by Xunta de Galicia (Project ED431C 2018/57