El estado y las relaciones internacionales

El Estado-Nación y La Soberanía son conceptos claves en las relaciones internacionales. Ambos conceptos están íntimamente vinculados con la ciencia política y las relaciones internacionales contemporáneas. En el presente capítulo se abordara la importancia del Estado-Nación en el sistema internacional y la participación de México a través del tiempo en la esfera global, para inalizar con las conclusiones, actividades y la bibliografí

Reliability Improvement in III-V Concentrator Solar Cells by Means of Perimeter Protection

This paper presents the evolution in the strategy to assess the reliability of III-V solar cells and a new thermal ageing test carried out over GaAs single junction solar cells at three different temperatures (130, 150 and 170° C). The perimeter of the solar cells has been protected with silicone, which seems to be an effective way of enhancing the reliability of the solar cells. A preliminary analysis of the results indicates a mean time to failure (MTTF) one order of magnitude larger than the one obtained in a previous thermal test with the perimeter uncoated

Simultaneous optimization of even flow and land and timber value in forest planning: a continuous approach

Background: Forest management planning involves deciding which silvicultural treatment should be applied to each stand and at what time to best meet the objectives established for the forest. For this, many mathematical formulations have been proposed, both within the linear and non-linear programming frameworks, in the latter case generally considering integer variables in a combinatorial manner. We present a novel approach for planning the management of forests comprising single-species, even-aged stands, using a continuous, multi-objective formulation (considering economic and even flow) which can be solved with gradient-type methods. Results: The continuous formulation has proved robust in forest with different structures and different number of stands. The results obtained show a clear advantage of the gradient-type methods over heuristics to solve the problems, both in terms of computational time (efficiency) and in the solution obtained (effectiveness). Their improvement increases drastically with the dimension of the problem (number of stands). Conclusions: It is advisable to rigorously analyze the mathematical properties of the objective functions involved in forest management planning models. The continuous bi-objective model proposed in this paper works with smooth enough functions and can be efficiently solved by using gradient-type techniques. The advantages of the new methodology are summarized as: it does not require to set management prescriptions in advance, it avoids the division of the planning horizon into periods, and it provides better solutions than the traditional combinatorial formulations. Additionally, the graphical display of trade-off information allows an a posteriori articulation of preferences in an intuitive way, therefore being a very interesting tool for the decision-making process in forest planningS

Methods to Manage Information Sources for Software Product Managers in the Energy Market - A Reference Model Catalog for the Energy Market

The German energy market is facing several challenges due to changes in regulation, technical advancements as well as increasing energy costs and climate achievements like CO2 reduction. This results in changing requirements for companies in the energy market and thus business information systems, which support their core tasks and processes. Software product managers in energy and software developing companies in charge of driving the functional development of information systems have to deal with these challenges and need to develop new information systems or enhance existing ones. Conceptual models proved helpful to design and implement information systems within several industries. However, identification and management of models as well as impact analysis of model changes results difficult. This contribution describes methods to construct, use and maintain a domain specific reference model catalogue to support requirements analysis for software product manager in the German electricity and gas market

The Moncloa in Twitter: a quantitative analysis in the post-COVID era

El fin de la fase aguda de la pandemia, inicia una vuelta a la normalidad en convivencia con el Coronavirus. Así, se inicia un periodo de transición e incertidumbre social, política y económica que, para la OMS y el FEM, podría implicar un reinicio de carácter mundial desde principios más equilibrados. El objetivo de este trabajo es identificar las claves que marcan el comportamiento relacional del Gobierno de España en Twitter desde su cuenta oficial @Desdelamoncloa, en relación con estos principios y los intereses de la población. Metodología: se realiza un análisis cuantitativo (análisis de contenido) multivariable en SPSS (coeficiente alfa de Krippendorff = 0,867) sobre un corpus de 2735 tuits emitidos entre el 1 de abril de 2021 y el 30 de marzo de 2022. Resultados: los resultados muestran una mayor prevalencia de contenido con carácter institucional y económico, el empleo de un lenguaje formal/solemne, y regularidad en la frecuencia de emisión por fecha y hora (Jordan, 2017; Acebes y Montanera, 2019). Discusión y conclusiones: Twitter se consolida como una poderosa herramienta de gestión de las relaciones en el ámbito institucional (Marcos-García, 2021; Castillo-Esparcia et al., 2020a) orientada a generar confianza en la opinión pública (Greenhill, 2020; Hucker, 2020), pero se observa: a) un relevante desajuste entre las temáticas de los mensajes emitidos y los intereses de la población en este periodo de transición y, b) consolida las tesis que destacan una infrautilización institucional de su potencial interactivo (Rivas-de-Roca et al., 2021).Introduction: The end of the acute phase of the pandemic, begins a return to normality in coexistence with the Coronavirus. Thus, a period of transition and social, political and economic uncertainty begins that, for WHO and WEF, could imply a global reset from more balanced principles. The objective of this work is to identify the keys that mark the relational behavior of the Government of Spain on Twitter from its official account @DesdelaMoncloa, in relation to these principles and the interests of the population. Methodology: multivariate quantitative analysis (content analysis) is performed in SPSS SPSS (Krippendorff alpha coefficient = 0.867) over a corpus of 2735 tweets issued between April 1, 2021 and March 30, 2022. Results: the results show a higher prevalence of content with an institutional and economic character, the use of a formal/solemn language, and regularity in broadcast frequency by date and time (Jordan, 2017; Acebes and Montanera, 2019). Discussion and conclusions: Twitter is consolidated as a powerful relationship management tool in the institutional field (Marcos-García, 2021; Castillo-Esparcia et al., 2020a) aimed at building trust in public opinion (Greenhill, 2020; Hucker, 2020), but it is observed: a) a significant mismatch between the themes of the messages issued and the interests of the population in this period of transition and, b) consolidates the theses that highlight an institutional underutilization of its interactive potential (Rivas-de-Roca et al., 2021)

Total replacement of recycled aggregate and treated wastewater: concrete recycling in extremis

Million tons of construction and demolition waste (CDW) are generated every year around the world, and most of them are not adequately disposed, generating significant pollution on water, soil and air. Additionally, the use of freshwater in industrial processes, such as the production of cement, concrete manufacturing and curing for newly-built structures; has damaged the health of our freshwater ecosystems, reducing their volume and hindering their natural cycle of renovation. Therefore, the incorporation of recycled aggregate (RA) and treated wastewater (TW) as substitutes for the usual aggregates (UA) and freshwater, could generate significant environmental benefits. In this research, a comparative analysis of the experimental results of the properties of fresh and hardened concrete with different replacement percentage of UA for RA, is presented; and as an innovation the use TW. The results show that, regardless of the replacement percentage and use of treated wastewater, a concrete with RA and TW (recycled concrete in extremis, CRiE) had a satisfactory and acceptable or equivalent performance, not differing significantly from the performance of conventional concrete (CC), confirming that the use of RA for concrete building is feasible.Peer ReviewedPostprint (published version

On the development of a MODEM for data transmission and control of electrical household appliances using the low-voltage power-line

This paper presents a CMOS 0,6μm mixed-signal MODEM ASIC for data transmission on the low-voltage power line. The circuit includes all the analog circuitry needed for input interfacing and modulation/demodulation (PLL-based frequency synthesis, slave filter banks with PLL master VCO for tuning, decision circuitry, etc.) plus the logic circuitry needed for control purposes. The circuit operates correctly in the whole industrial temperature range, from -45 to 80°C, under 5% variations of the 3.3V supply voltage.Comisión Interministerial de Ciencia y Tecnología FD97-1611(TIC)Ministerio de Ciencia y Tecnología TIC200 1-092

CMOS mixed-signal MODEM for data transmission and control of electrical household appliances using the low-voltage power-line

This paper presents a CMOS 0.6μm mixed-signal MODEM ASIC for data transmission using the low-voltage power line. This circuit includes all the analog blocks needed for input interfacing and modulation/demodulation (PLL-based frequency synthesis, slave filter banks with PLL master VCO for tuning, and decision circuitry) plus the logic circuitry needed for control purposes. The circuit operates correctly within the industrial temperature range, from -45 to 80°C, under 5% variations of the 3.3V supply voltage.Comisión Interministerial de Ciencia y Tecnología 1FD97-1611(TIC)Ministerio de Ciencia y Tecnología TIC2001-092

Water Management Using Drones and Satellites in Agriculture

This document intends to be a presentation of the Special Issue “Water Management Using Drones and Satellites in Agriculture”. The objective of this Special Issue is to provide an overview of recent advances in the methodology of using remote sensing techniques for managing water in agricultural systems. Its eight peer-reviewed articles focus on three topics: new equipment for characterizing water bodies, development of satellite-based technologies for determining crop water requirements in order to enhance irrigation efficiency, and monitoring crop water status through proximal and remote sensing. Overall, these contributions explore new solutions for improving irrigation management and an efficient assessment of crop water needs, being of great value for both researchers and advisors.S

Evaluación del almacenamiento temporal de agua en depresiones del microrrelieve

Jornadas de Investigación en la Zona No Saturada de Suelo, ZNS 2005, A Coruña, 16-18 de noviembre de 2005La rugosidad de la superficie del suelo es un parámetro que puede afectar considerablemente a las propiedades hidrológicas del mismo. La estimación del almacenamiento temporal de agua en microdepresiones (ATM), esto es, el volumen de agua que puede ser almacenado en las hondonadas antes del inicio de la escorrentía, resulta útil para la profundización en el conocimiento y la modelación de los procesos erosivos. El objetivo de este trabajo es comparar diferentes métodos de cálculo del ATM, empleando modelos empíricos y geométricos, en superficies de suelo cubiertas con cantidades crecientes de residuos vegetales. Las estimaciones de ATM se efectuaron a partir de medidas de microrrelieve que se efectuaron mediante rugosímetro de agujas y rugosímetro laser en redes de 30mm x 30 mm y de 2 mm x 2 mm, respectivamente. La magnitud del volumen de ATM depende en gran medida de las condiciones de borde consideradas en la modelación y de las características de la red de muestreo. Debido al pequeño tamaño de las parcelas experimentales, parece realista usar modelos que tengan en cuenta el efecto de borde. Cuando se modifica la resolución de la red de muestreo, aumentando el tamaño de la celdilla, no se aprecian diferencias significativas en los valores de la rugosidad aleatoria, RR, ni tampoco del almacenamiento potencial en microdepresiones, ATM, estimado teniendo en cuenta el efecto de borde. Sin embargo, si se considera que existe drenaje libre en los bordes de la pequeña parcela experimental los valores de ATM tienden a disminuir conforme disminuye la resolución. En ambos casos, con y sin efecto de borde, se aprecia un aumento de la imprecisión de los datos de RR y ATM al aumentar la escala de medida. La topografía de la superficie del suelo presenta una gran dependencia espacial, que está relacionada con el tamaño de unidades estructurales como terrones y agregados, y el almacenamiento temporal se ve afectado, de modo considerable, por la escala de medida y el tamaño de la parcela experimental / Soil surface roughness is a parameter that may influence considerably the hydraulic properties at the soil surface. Evaluation of maximum water depression storage (MDS), i.e. the absolute volume of water that potentially can be stored at a rough surface before water runoff starts, will be useful to increase knowledge and to improve modelling of erosive processes. This work aims at comparing different MDS estimation methods, using both empirical and geometrical models in soil surfaces covered with different crop residue amounts. Point elevations were measured by means of a pin meter and a laser relief meter; using 30 mm x 30 mm and 2 mm x 2 mm grids, respectively. Surface water depression storage was found to depend mainly on the type of boundary conditions assigned to the test surfaces and on the grid parameters. Because of the small size of the experimental plots, it was concluded that models taken into account plot boundary effects result in more realistic estimations. When resolution of the experimental plot is modified by increasing grid size, only minor differences in roughness roughness, RR, and maximum depressional storage, MDS, assessed by taking into account boundary effects values are not, were observed. However, when modelling is performed under free drainage conditions at the boundary of the small experimental plots, MDS values were found to decrease with decreasing grid resolution. In both studied cases, i.e. with and without boundary effect, accuracy of RR and MDS values increases as the grid resolution increases. Soil surface topography is characterized by high spatial dependence, associated with the size of soil structural units, aggregates and clods and maximum depressional storage is controlled by the upper and lower cutoff length scales of the sampled plot, i. e., grid resolution and plot siz