Energy consumption in the US reconsidered. Evidence across sources and economic sectors

This study analyzes the impact of GDP shocks in USA on primary energy consumption and the reverse impact in a comprehensive and novel framework, distinguishing by economic sectors (commercial, industrial, residential and transportation) and energy source, i.e., total fossil (coal, natural gas and petroleum), nuclear, and renewable (hydroelectric, geothermal and biomass) for the period 1973:1 to 2015:2. To this end, we apply Granger causality analysis through the Hatemi-J [1] and Toda and Yamamoto [2] approaches from a time series perspective to evaluate the existence of asymmetries on this bidirectional relationship. The empirical results suggest that the impact of GDP on primary energy consumption is heterogeneous and energy source-specific, and an asymmetric behavior appears among cycles. Moreover, it seems clear that the US economy is highly dependent on petroleum energy consumption. The renewable energy sources do not seem to show any relationshipsources seem to show no relationship with economic growth, and finally, our results suggest that energy consumption in the industrial sector is key to economic growth and is also very sensitive to negative economic shocks

La acción tutorial en la Universidad de Sevilla: Una apuesta por la docencia de calidad

La Universidad de Sevilla, en su apuesta por una docencia de calidad, contempló, en su I Plan Propio de Docencia (2008-2012), acciones tendentes a fomentar el desarrollo de la orientación y la acción tutorial. La consideración de estas acciones pone de manifiesto la importancia de los sistemas de acogida, la orientación y la tutorización como un elemento esencial de la calidad de la enseñanza. En este trabajo presentamos el proceso que se ha llevado a cabo en la Universidad de Sevilla para potenciar la orientación y la acción tutorial como elementos de una docencia de calidad, las cuales han desembocado en la creación de un Sistema Integral de Orientación y Tutoría (US-Orienta), apoyado por el II Plan Propio de Docencia (2013-2016) y coordinado desde el recién creado Secretariado de Orientación

Energy consumption in the US reconsidered. Evidence across sources and economic sectors

This study analyzes the impact of GDP shocks in USA on primary energy consumption and the reverse impact in a comprehensive and novel framework, distinguishing by economic sectors (commercial, industrial, residential and transportation) and energy source, i.e., total fossil (coal, natural gas and petroleum), nuclear, and renewable (hydroelectric, geothermal and biomass) for the period 1973:1 to 2015:2. To this end, we apply Granger causality analysis through the Hatemi-J [1] and Toda and Yamamoto [2] approaches from a time series perspective to evaluate the existence of asymmetries on this bidirectional relationship. The empirical results suggest that the impact of GDP on primary energy consumption is heterogeneous and energy source-specific, and an asymmetric behavior appears among cycles. Moreover, it seems clear that the US economy is highly dependent on petroleum energy consumption. The renewable energy sources do not seem to show any relationshipsources seem to show no relationship with economic growth, and finally, our results suggest that energy consumption in the industrial sector is key to economic growth and is also very sensitive to negative economic shocks

Monocapas de ácidos grasos. III. Ácidos paimítico, láurico y oleíco sobre disoluciones acuosas que contienen solutos con grupos funcionales alcohólicos.

Monocapas de ácidos grasos. III. Ácidos palmítico, láurico y oleico sobre disoluciones acuosas que contienen solutos con grupos funcionales alcohólicos. Se ha estudiado la influencia que ejercen la longitud y la insaturación de la cadena acílica sobre las características de las monocapas de ácidos grasos sparcidas sobre medios acuosos que contienen etanol, glicerina, glucosa o sacarosa, utilizando una balanza de superficie de tipo Langmuir. La estabilidad de la monocapa es función de la longitud de la cadena acílica y de la presencia de insaturación. En general, los mismos factores que disminuyen la estabilidad de la monocapa pueden favorecer las transiciones iiacia configuraciones con estructuras más expandidasMonolayers of fatty acids. III. Palmitic, Laurie and Oleic Acids on aqueous solutions containig solutes witli alcoholic functional groups. Tiie influence exerted by the length or the insaturation of acyl chain on characteristics of fatty acid monolayers spread on aqueous solutions containing ethanol, glycerol, glucose or sucrose, is studied using a Langmuir type surface balance. The monolayer stability is function of acyl chain length and presence of insaturarion. Generally, the factors decreasing monolayer stability can help transformations towards configurations with more expanded structures

Monocapas de ácidos grasos I. Ácido esteárico sobre disoluciones acuosas de etanol

Monocapas de ácidos grasos. I. Acido esteárico sobre disoluciones acuosas de etanol. Se ha estudiado la estructura y estabilidad de monocapas de ácido esteárico esparcidas sobre disoluciones acuosas que contienen etanol. Las experiencias se han realizado en una iaalanza de superficie comercial tipo Langmuir y se ha operado en condiciones isotérmicas. Las monocapas presentan estructuras de tipo sólida o de líquido condensado en función de la concentración de etanol en la subíase. La estructura que adopta la monocapa es prácticamente independiente de la temperatura. La pérdida de moléculas de ácido esteárico de la monocapa por disolución en la subíase se incrementa a los valores más elevados de temperatura y de concentración de etanol.Monolayers of fatty acids. I. Stearic acid on aqueous solutions of ethanol. The structure and stability of fatty acid monolayers spread on aqueous solutions with ethanol has been studied. The experiments were carried out isothermically using a commercial Langmuir balance (Lauda). Monolayers exhibit solid or condensed liquid structure depending of the ethanol concentration in the subphase. Temperature has not a significant influence on the monolayer. Structure there is a loss of stearic acid film through solution into the adjacent subphase. This loss is increased with the temperature and ethanol concentration in the subphase

Monolayers of fatty acids. II. Stearic acid on aqueous solutions containing solutes with alcoholic functional groups

Se ha estudiado la estructura y estabilidad de monocapas de ácido esteárico esparcidas sobre disoluciones acuosas que contienen glicerina, glucosa y sacarosa. Las experiencias se han realizado en una balanza de superficie connercial tipo Langmuir y se ha operado en condiciones isotérmicas. Las monocapas presentan un polimorfismo estructural que depende de la composición del medio acuoso y de la temperatura. La estabilidad de la monocapa está muy relacionada con la estructura que adopta sus moléculas. Las monocapas con estructuras más expandidas suelen poseer mayor estabilidad.The structure and the stability of stearic acid monolayers spread on aqueous solutions with glycerol, glucose or sucrose are studied using a commercial film balance (Lauda). The experiments were carried out isothermically. Monolayers exhibit structural polymorphism depending on temperature and subphase composition. The stability of the molecules on the subphase is a function of their structure. Generally, the most stable monolaye|rs are those with more expanded structure

Influence of pH and type of acid anion on the linear viscoelastic properties of Egg Yolk

Libro en acceso abierto en Internet. Patrocinador: Andalousian Government through the project TEP-6134-2010

Interfacial/foaming properties and antioxidant activity of a silkworm (Bombyx mori) pupae protein concentrate

The current consumer demand for healthier diets, the growing interest in the search for new sources of protein, and the desire to reduce the negative effects on the environment have increased interest in the study of insect proteins. The present study focused on the technofunctional characteristics (interfacial and foaming properties) and the in-vitro antioxidant activity of a protein concentrate obtained from silkworm (Bombyx mori) pupae (SPC). The isoelectric point of the SPC was close to pH 4.0–5.0 as determined by protein solubility and z potential analysis. Given that the SPC had solubilities of ~50% and z potentials of ~20 mV at pH 2.0 and 8.0, it was decided to further study SPC properties at these pH values. The supernatant obtained after adjustment of SPC to pH 8.0 showed higher (p < 0.05) antioxidant activity than that at pH 2.0 when analysed by the ferric reducing antioxidant power (FRAP) assay (168.0 ± 3.0 V. 43.5 ± 8.1 μmol Trolox Eq. ·g−1 protein). However, no significant differences in antioxidant activity were found between pH 2.0 and 8.0 when using the oxygen radical absorbance capacity (ORAC) assay (1826.0 ± 131.9 vs. 1659.2 ± 46.8 μmol Trolox Eq. g−1 protein). The interfacial properties of SPC were determined at pH 2.0 and 8.0 during protein adsorption and after reaching the pseudo equilibrium state by means of dilatational and interfacial shear rheology following by foaming capacity and stability analyses. Faster adsorption kinetic values were obtained at pH 8 ( Vs. at pH 2.0). However, lower kinetic values at pH 2.0 increased the elastic behaviour of the viscoelastic interfacial film formed (E's ⁓ 30 mN/m at pH 2.0 V. E's ⁓ 20 mN/m at pH 8.0), which can be related with the higher protein sizes found at pH 2.0. These rearrangements of the SPC components appeared to increase its foaming capacity, whereas the foaming capacity of SPC adjusted to pH 8.0 was minimal.University of Seville for the VPPI-US grant (Ref.-II.5)Ministerio de Ciencia, Innovación y Universidades (España) / FEDER RTI2018-097100-B-C2

Desarrollo de materiales poliméricos porosos mediante electrohilado

Si el diámetro de las fibras que forman una matriz de polímero se reduce desde una escala micrométrica a nanométrica, se produce una serie de características extraordinarias. Entre estas características se encuentran un gran aumento en el área superficial (del orden de 1000 veces mayor), una mayor flexibilidad de la funcionalidad de la superficie y una mejor resistencia mecánica (por ejemplo, rigidez, resistencia a la tracción). Estas propiedades hacen que las matrices de polímeros nanofibrilares sean excelentes candidatos en muchas aplicaciones de gran importancia, que incluyen aplicaciones químicas, alimentarias, farmacéuticas, electrónicas o biomédicas. Hay varios parámetros que están íntimamente relacionados con las propiedades y características de las fibras obtenidas mediante electrospinning, por lo que su control durante la ejecución del proceso es indispensable. Juegan un papel importante en la formación y estructura de las fibras. En el siguiente trabajo, procedemos a estudiar tres variables del proceso de electrohilado; en primer lugar, se estudiará el efecto de la concentración del disolvente; en segundo lugar, se estudiará cómo las nanofibras obtenidas afectan a un cambio en el valor de la diferencia de potencial aplicada; y, finalmente, se estudiará el efecto producido por la humedad en el ambiente.If the diameter of the fibers that form a polymer matrix is reduced from a micrometric to nanometric scale, a series of extraordinary features take place. Among these features are a huge increase in surface area (in the order of 1000 times higher), a greater flexibility of the surface functionality and a better mechanical resistance (e.g. rigidity, tensile strength). These properties make nanofibrillary polymer matrices excellent candidates in many applications of great importance, including chemical, food, pharmaceutical, electronic or biomedical applications. There are several parameters that are intimately related to the properties and characteristics of the fibers obtained by means of electrospinning, so their control during the execution of the process is indispensable. They play an important role in the formation and structure of fibers. In the following work we proceed to study three variables of the electrospinning process; firstly, the effect of the concentration of the solvent will be studied; secondly, it will be studied how the nanofibers obtained affect a change in the value of the applied potential difference; and, finally, the effect produced by humidity in the environment will be studied.Plan Propio de la Universidad de Sevilla Proyecto: 2017/00000962Ministerio de Economía y Competitividad (España) CTQ2015-71164-

The delimitation of metropolitan areas as a governance instrument: the case of the Valencian Community

Partiendo de la naturaleza multidimensional, flexible y abierta de los procesos urbanos, el trabajo propone una metodología de definición y delimitación de áreas metropolitanas con fines normativos, asumiendo que existen tantas potenciales delimitaciones como perspectivas desde las que es posible abordar esta tarea. El enfoque propuesto se articula en varios pasos que toman en consideración aspectos normativos, vínculos funcionales, características morfológicas, delimitaciones preexistentes, la gobernanza multinivel y las redes de cooperación. En el trabajo se ilustra esta aproximación aplicándola en la Comunidad Valenciana, cuyos espacios metropolitanos forman un caso de estudio idóneo al tratarse de ejemplos paradigmáticos de tipos distintos de configuración metropolitana. Los análisis realizados, extrapolables a otros territorios, muestran que en el enfoque propuesto el producto final no es tanto un mapa de las áreas metropolitanas valencianas como la sistematización de los distintos aspectos que deben considerarse en el proceso de definición. Así, son igualmente relevantes las fases del proceso, la discusión en ellas recogida, y no únicamente las fronteras que delimitan las áreas metropolitanas. Ello facilita que estas sean modulables, adaptables a la coyuntura específica en que son adoptadas, a través de la consideración crítica de las decisiones tomadas en cada una de las etapas.Based on the multidimensional, flexible and open nature of urban processes, the paper proposes a methodology for defining and delimiting metropolitan areas for normative purposes, assuming that there are as many potential delimitations as different perspectives from which it is possible to approach this task to suit public policy objectives. The proposed approach is articulated in several steps that take into consideration normative aspects, functional links, morphological characteristics, pre-existing delimitations, multilevel governance and intermunicipal cooperation networks. The paper illustrates this approach by applying it to the Valencian Community, whose metropolitan areas form an ideal case study as they are paradigmatic examples of different types of metropolitan configuration. The analyses carried out, which can be extrapolated to other territories, show that in the proposed approach the final product is not so much a map of the Valencian metropolitan areas as the systematization of the different aspects to be considered in the definition process and in making it available to the agents involved. Thus, the deliverable are the phases of the process, the discussion therein collected, and not only the boundaries that delimit the metropolitan areas. This facilitates that these are modulable, adaptable to the specific circumstances in which they are adopted, through the critical consideration of the decisions taken in each of the stages.Proyectos PID2020/112734RB-C31 y PID2020-114896RB-I00 (Agencia Estatal de Investigación, AEI/10.13039/501100011033; Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020) y AICO/2021/062 (Conselleria de Innovación, Universidades, Ciencia y Sociedad Digital; Programa de I+D+I de la Comunitat Valenciana)