The relationship between ARIMA-GARCH and unobserved component models with GARCH disturbances

The objective of this paper is to analyze the consequences of fitting ARIMA-GARCH models to series generated by conditionally heteroscedastic unobserved component models. Focusing on the local level model, we show that the heteroscedasticity is weaker in the ARIMA than in the local level disturbances. In certain cases, the IMA(1,1) model could even be wrongly seen as homoscedastic. Next, with regard to forecasting performance, we show that the prediction intervals based on the ARIMA model can be inappropriate as they incorporate the unit root while the intervals of the local level model can converge to the homoscedastic intervals when the heteroscedasticity appears only in the transitory noise. All the analytical results are illustrated with simulated and real time series

La dimensión constitucional de la guerra: Conflictos armados e intervenciones militares en el extranjero

En España, como ocurre en la mayor parte de los países de nuestro entorno, la participación militar en operaciones armadas fuera del territorio nacional ha devenido en las últimas décadas una realidad cada vez más compleja y, por esta misma razón, cada vez más divergente con, y menos aprehensible para, las normas jurídicas que disciplinan las funciones de las Fuerzas Armadas, los procedimientos de autorización de las acciones bélicas, o los límites materiales de estas últimas

Word-formation from the names of United States presidents

[Abstracts] This paper collects and analyzes the words formed from the names of American presidents, from Washingtonite to Bidenian. The following objectives are set: to find out which formative elements are the most productive in our field of study, to determine the meaning of the neologisms they form and to identify which presidents’ names have served as a morphological base for the creation of a greater number of words, as well as the most frequent ones. Prior to our study, a theoretical background is set out in which the work is contextualized within word-formation in general and deonomastics in particular, a subdiscipline that examines the formation of words from proper nouns. The method followed is a corpus-based study using two sources: the American English Google Books corpus, which was employed to search for words from the end of the 18th century until 2009, and the NOW corpus, which was utilized to seek words appearing from 2010 onwards. Neologisms have been searched using the wildcard tool by inserting an asterisk before or after the names of each president. Once all the words were collected, they were classified according to the word-formation mechanism involved in their creation. It is found that most words formed from the names of American presidents are derived by suffixation, so the analysis is concentrated on words formed by each of the most productive suffixes. In our object of study, these are -esque, -ian, -ite, -ism and -iana. To meet the objectives, the analysis has been divided into two parts. Foremost, a quantitative and diachronic study of the words formed by each of the suffixes is conducted; then, a semantic study is undertaken. The following conclusions have been reached for each suffix. First, the suffix -esque forms adjectival derivatives whose most frequent meaning is ‘resembling X’, and is applied to names of American presidents from the late 19th century to the present. Second, the suffixes -ian and -ite are studied together, as they both form derivatives that function either as adjectives or as nouns; -ian tends to form adjectival derivatives of relational meaning, while -ite usually forms nouns meaning ‘follower or supporter of’, although both suffixes may adopt the characteristics of the other. They are applied from the earliest presidents to the present day; in particular, -ian is the one which derives the types with the highest number of tokens of all suffixes. Third, -ism and -iana form nominal derivatives. On the one hand, words with -ism tend to signify ‘political doctrine of X’, but when attached to -ian the semantic modulation is ‘political doctrine inspired by X’. This suffix is also applied since the beginning of the 19th century and is the one that derives the largest number of types of all suffixes. Finally, the suffix -iana forms derivatives whose meaning is ‘the collected sayings, wisdom or artifacts connected with X’; it is applied since the first rulers as well. The presidents whose names are most productive in word-formation are Thomas Jefferson, Abraham Lincoln, Woodrow Wilson, Ronald Reagan and Donald Trump.Traballo fin de grao (UDC.FIL). Inglés: estudios lingüísticos y literarios. Curso 2022/202

La reforma de las pensiones públicas a través de la definición de sus principios organizativos.

Sin resume

Strategic assessment of transport infrastructure Plans on European integration. Application for the Spanish Strategic Transport and Infrastructure Plan 2005-2020

Traditional transport infrastructure assessment methodologies rarely include the full range of strategic benefits for the transportation system. One of these benefits is the contribution to cross-border integration. However, this is a key issue in strategic planning and decision-making processes, as its inclusion may increase the probability of large-scale transport infrastructure projects being funded. This paper presents a methodology for the measurement of the contribution of Transport Infrastructure Plans to cross-border integration. The methodology is based on the measurement of the improvement in network efficiency in cross-border regions of neighboring countries, via accessibility calculations in a Geographical Information System (GIS) support. The methodology was tested by applying it to the ambitious road and rail network extensions included in the Spanish Strategic Transport and Infrastructure Plan (PEIT) 2005-2020. The results show significant and important network efficiency improvements of the PEIT outside the Spanish border. For the road mode, while the Spanish average accessibility improvement accounts for 2.6%, average improvements in cross-border regions of France and Portugal are of 1.8%. And for the rail mode, the corresponding Spanish value is 34.5%, whereas in neighboring regions it accounts for 20.2%. These results stress the significant importance of this strategic benefit and the consequent need for its inclusion in strategic planning processes. Finally, the paper identifies the potential of the methodology when applied at different administrative levels, such as the local or state levels

Gas identification with tin oxide sensor array and self-organizing maps: adaptive correction of sensor drifts

Low-cost tin oxide gas sensors are inherently nonspecific. In addition, they have several undesirable characteristics such as slow response, nonlinearities, and long-term drifts. This paper shows that the combination of a gas-sensor array together with self-organizing maps (SOM's) permit success in gas classification problems. The system is able to determine the gas present in an atmosphere with error rates lower than 3%. Correction of the sensor's drift with an adaptive SOM has also been investigate

Motivations to consume ecological foods in alternative food networks (AFNs) in southern Spain

Purpose The purpose of this paper is to identify the motivations to consume ecological foods in alternative food networks (AFNs). Design/methodology/approach In total, 150 questionnaires were applied; the questionnaire was adapted from Food Choice Questionnaire (Steptoe et al., 1995). Data were analyzed by means of multivariate statistics with factor and cluster analysis. In order to identify statistical differences (p<0.05), Kruskal–Wallis and Mann–Whitney nonparametric tests were performed. Findings Ten factors or motivations were found: social ecological concern, nutritional content, sensory aspects, certifications, naturalness, specialized consumption, trust in the seller, economic aspects, health and availability. Four groups were obtained and called: citizen consumers, in-process citizen consumers, conscious social consumers with no interest in certifications and conscious pragmatic consumers. It is concluded that differentiated consumers visit these establishments and their motivations are diverse, albeit they concur, to a varying extent, with the objectives of AFNs, finding a mixture of hedonic and ethical motivations. Practical implications This sort of works about specific places of consumption as well as specific consumers, in this case ecological, contributes to the development of future social research on other contexts, different consumers and products. Originality/value This sort of research has been carried out in various European cities, with a number of foods and over various sales channels; however, at present there is a debate around AFNs and the veracity of their goals. This way, the present work can contribute with an answer to whether the goals match the motivations of consumers

La negociación colectiva sobre salud laboral a partir de la Ley de Prevención de Riesgos Laborales.

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Diseño de un silo de fondo cónico para almacenar maíz con capacidad de 25 toneladas con carga y descarga

The silo is the most important form of storage the grain used in the agricultural industry, thanks to its efficiency for preserving the quality and nutrients of the grain of maize, nowadays maize is an essential part in the economy of our country the same form the maize also important for human consumption because of their excellent properties to stimulate the mind, strengthen the brain and help our organism. This project is oriented to the structural design of a cylindrical silo made of sheet metal with a capacity of twenty-five tons,has the advantage of being removable for easy transport of it, also it will store maize efficiently and safely. with this proyect developing not only we will get adecuate grain storage, but the transport and assembly of the container is also provided. In this degree work we know the ways to preserve the grain of corn in addition to its features in order to facilitate the storage of grain in the silo. The silo is designed based on the Eurocódigo1: Actions in silos and tanks structures (EN 1991-4), which gives rules for structural calculation, it is performed by the influence of various parameters such as the density of grain, pressures acting on the silo walls, specific gravity among others.Los silos son las formas de almacenamiento de grano más importantes utilizadas en la industria agrícola por su eficiencia al preservar la calidad y los nutrientes del grano de maíz, en la actualidad el maíz es parte fundamental en la economía de nuestro país como también es importante para el consumo humano debido a sus excelentes propiedades para estimular el ánimo y fortalecer al cerebro gracias a que contiene un gran número de proteínas asimilables por el organismo. Este proyecto está orientado al diseño estructural de un silo cilíndrico elaborado de chapa metálica de 25 toneladas tiene la ventaja de ser desmontable para su fácil transportación, Además almacenara maíz de forma eficiente y segura. Al desarrollar este proyecto no solo se obtendrá un adecuado almacenamiento del grano, sino también, se facilitará el transporte y armado del recipiente. En el trabajo de grado se conoce las formas para preservar al grano de maíz además de sus características con el fin de facilitar el almacenaje del grano en el silo. El silo se encuentra diseñado en base al Eurocódigo1: Acciones en estructuras silos y depósitos (UNE-EN 1991-4), la cual da unas reglas para el cálculo estructural que se realiza bajo la influencia de distintos parámetros como la densidad del grano, capacidad de almacenamiento, presiones que actúan sobre las paredes del silo, peso específico entre otras