An empirical comparison of the performance of alternative option pricing models

Published as an article in: Investigaciones Economicas, 2005, vol. 29, issue 3, pages 483-523.option pricing, conditional volatility, SNN Nonparametric estimator

Fin de Arafat: La imagen en el mundo

Decenes Jornades de Foment de la Investigació de la FCHS (Any 2004-2005

The Kramer sampling theorem revisited

The classical Kramer sampling theorem provides a method for obtaining orthogonal sampling formulas. Besides, it has been the cornerstone for a significant mathematical literature on the topic of sampling theorems associated with differential and difference problems. In this work we provide, in an unified way, new and old generalizations of this result corresponding to various different settings; all these generalizations are illustrated with examples. All the different situations along the paper share a basic approach: the functions to be sampled are obtaining by duality in a separable Hilbert space H through an H -valued kernel K defined on an appropriate domain

Determinación de los tiempos estándar de producción y diseño de un sistema de costeo de productos : análisis de capacidad de la línea de producción principal en Remodularsa Madeval Fábrica

The thesis project is a guide to establish a design of a costing system for Madeval's company products. This company manufactures modular furniture for closet, kitchen and restroom. In order to establish an adequate costing system, we found the need to accomplish an uprising of processes. With this we were able to record the operations of every one of the production's processes. The processes’ flowcharts, of the main production line, were used as a base to perform an analysis of standard times of these processes. For the development of the aforementioned analysis, we recorded time data of each one of the operations of the principal processes.El proyecto de tesis presente se orienta a establecer un diseño de un sistema de costeo de los productos de la empresa Madeval, la cual se dedica a la fabricación de muebles modulares de closet, cocina y baño. Para determinar el diseño del sistema de costeo adecuado, se encontró la necesidad de realizar un levantamiento de procesos el cual lleve registro de las operaciones de cada uno de los procesos de producción. Los flujogramas de procesos de la línea principal de producción se utilizaron como base para poder proseguir a un análisis de tiempos estándar de cada uno de estos procesos. Para el desarrollo de dicho análisis, se tomaron datos de tiempos de cada una de las operaciones predeterminadas de los procesos principales, y se analizaron los datos mediante métodos estadísticos que permitan establecer las ecuaciones de tiempos estándar de cada proceso

Kimura disease as an uncommon cause of persistent hypereosinophilia: a diagnostic challenge

Kimura disease (KD) is an unusual inflammatory disease of unknown etiology. Despite being described many years ago, KD might cause diagnostic difficulty or be confused with other conditions. Here, we present a 33-year-old Filipino woman who was referred to our hospital for evaluation of persistent eosinophilia and intense pruritus. Blood analysis and peripheral blood smear review showed high eosinophil counts (3.8 x109/L, 40%) that did not show morphological abnormalities. Besides, high serum IgE concentration was detected (33,528 kU/L). Serological tests were positive for Toxocara canis and treatment with albendazol was initiated. Nevertheless, increased eosinophil counts were still present after several months, alongside with high serum IgE concentrations and intense pruritus. During her follow-up, an inguinal adenopathy was detected. The biopsy revealed lymphoid hyperplasia with reactive germinal centers and massive eosinophil infiltration. Proteinaceous deposits of eosinophilic material were also observed. All these findings, together with peripheral blood eosinophilia and high IgE concentrations, confirmed the diagnosis of KD. The diagnosis of KD should be considered in the differential diagnosis of long-standing unexplained eosinophilia in association with high IgE concentrations, pruritus and lymphadenopathies

Dimensions That Influence the Creation of Brand Value of a Music Event and Its Influence on Attendee Satisfaction

Background: Music festivals are part of the cultural industry, and have become an evergrowing phenomenon. It is essential for organisers to identify whether the marketing strategies implemented are positive and effective in generating a competitive advantage. The aim of this study is to identify the elements that make up the brand equity of an emerging music festival, and to find out whether the overall brand equity determines the satisfaction and subsequent behaviours of festival-goers. Methods: Quantitative research was used by conducting an ad hoc structured survey during the development of a live music festival in May 2022. The questionnaire collects information about dimensions that make up the global brand value and how they influence satisfaction and behavioural intentions, consisting of a total of 33 indicators.; Results: Awareness, perceived quality, and loyalty are the most influential dimensions in shaping the brand of a festival. There is a correlation between the overall brand value and the satisfaction of the attendees, and that the latter influences the subsequent loyalty and recommendation of the event. Conclusions: The causal relationships between the dimensions of brand equity and overall brand equity are shown, where three of the four hypotheses are accepted. Similarly, the three hypotheses related to the influence of overall brand image and behavioural intentions are also accepte

Sentiment analysis of COVID-19 cases in Greece using Twitter data.

Syndromic surveillance with the use of Internet data has been used to track and forecast epidemics for the last two decades, using different sources from social media to search engine records. More recently, studies have addressed how the World Wide Web could be used as a valuable source for analysing the reactions of the public to outbreaks and revealing emotions and sentiment impact from certain events, notably that of pandemics. Objective: The objective of this research is to evaluate the capability of Twitter messages (tweets) in estimating the sentiment impact of COVID-19 cases in Greece in real time as related to cases. Methods: 153,528 tweets were gathered from 18,730 Twitter users totalling 2,840,024 words for exactly one year and were examined towards two sentimental lexicons: one in English language translated into Greek (using the Vader library) and one in Greek. We then used the specific sentimental ranking included in these lexicons to track i) the positive and negative impact of COVID-19 and ii) six types of sentiments: Surprise, Disgust, Anger, Happiness, Fear and Sadness and iii) the correlations between real cases of COVID-19 and sentiments and correlations between sentiments and the volume of data. Results: Surprise (25.32%) mainly and secondly Disgust (19.88%) were found to be the prevailing sentiments of COVID-19. The correlation coefficient (R2 ) for the Vader lexicon is &#8722; 0.07454 related to cases and &#8722; 0.,70668 to the tweets, while the other lexicon had 0.167387 and &#8722; 0.93095 respectively, all measured at significance level of p < 0.01. Evidence shows that the sentiment does not correlate with the spread of COVID-19, possibly since the interest in COVID-19 declined after a certain time

El mantenimiento de los bienes culturales como garantía para su conservación

La conservación del Patrimonio se debe basar fundamentalmente en la preservación. Cuando se trata de obras expuestas a la intemperie no resulta viable implantar medidas preventivas que permitan controlar las condiciones ambientales que influyen de manera determinante en el desarrollo de los procesos de deterioro. En estos casos, la conservación preventiva se debe centrar en mantener en buen estado los materiales de construcción y los elementos arquitectónicos, tanto estructurales como funcionales o de protección y en la aplicación de programas de mantenimiento. Este tipo de actuaciones permiten la detección precoz de los daños evitando un agravamiento de la patología y son, además, un mecanismo que rentabiliza las inversiones económicas que las instituciones encargadas de la tutela de los bienes culturales dedican a su restauración. Por otra parte, las labores de control y mantenimiento permiten evaluar la idoneidad de los tratamientos y de las soluciones adoptadas.The Conservation of Cultural Heritage must be based mainly upon preservation. When it comes to in situ outdoor works, it is not possible to apply preventive measures to control the environmental conditions that influence the deterioration process. In these cases, preventive conservation must be focused on maintaining both the structural and functional construction materials and the architectonical elements in a good state, or in protection and also implementation of maintenance programs. These kinds of actions will allow the early detection of damage, avoiding the worsening of the pathology. They will also make profitable the economic investment made for the restorations works by institutions responsible for the protection of cultural heritage. On the other hand, control and maintenance actions allow the assessment of the suitability of the adopted treatments and solutionsA conservação do Património deve-se basar fundamentalmente na preservação. Quando se está a tratar de obras expostas à intemperie, não resulta viável implantar medidas preventivas que permitam controlar as condições ambientais que influiem de maneira determinante no desenvolvimento dos processos de deterioração. Nestes casos, a conservação preventiva deve-se centrar em manter em bom estado os materiais de construção e os elementos arquitectónicos, tanto estructurais como funcionais ou de protecção, e na aplicação de programas de manutenção. Este tipo de actuações permitem a detecção precoz dos danos, evitando um agravamento da patologia e, além disso, são um mecanismo que rentabiliza as inversões económicas que as instituções encarregadas da tutela dos bens culturais dedicam à sua restauração. Por outro lado, as labores de controlo e manutenção permitem avaliar a idoneidade dos tratamentos e das soluções adotada

Types and Distribution of Bioactive Polyunsaturated Aldehydes in a Gradient from Mesotrophic to OligotrophicWaters in the Alborán Sea (Western Mediterranean)

Polyunsaturated aldehydes (PUAs) are bioactive molecules suggested as chemical defenses and infochemicals. In marine coastal habitats, diatoms reach high PUA production levels during bloom episodes. Two fractions of PUA can usually be analyzed: pPUA obtained via artificial breakage of collected phytoplankton cells and dissolved PUA already released to the environment (dPUA). In nature, resource supply arises as a main environmental controlling factor of PUA production. In this work, we monitored the vertical distribution and daily variation of pPUA associated with large-size phytoplankton and dPUA, at three sites located in the Alboran Sea from mesotrophic to oligotrophic waters. The results corroborate the presence of large-size PUA producers in oligotrophic and mesotrophic waters with a significant (58%-85%) diatom biomass. In addition to diatoms, significant correlations between pPUA production and dinoflagellate and silicoflagellate abundance were observed. 2E,4E/Z-Heptadienal was the most abundant aldehyde at the three sites with higher values (17.1 fg center dot cell(-1)) at the most oligotrophic site. 2E,4E/Z-Decadienal was the least abundant aldehyde, decreasing toward the oligotrophic site. For the first time, we describe the daily fluctuation of pPUA attributable to cellular physiological state and not exclusively to taxonomical composition. Our results demonstrate the persistence of threshold levels of dPUA deep in the water column, as well as the different chromatographic profiles of dPUA compared with pPUA. We propose different isomerization processes that alter the chemical structure of the released PUAs with unknown effects on their stability, biological function, and potential bioactivity