Modeling of the Bitcoin volatility through key financial environment variables: an application of conditional correlation MGARCH models

Since the launch of Bitcoin, there has been a lot of controversy surrounding what asset class it is. Several authors recognize the potential of cryptocurrencies but also certain deviations with respect to the functions of a conventional currency. Instead, Bitcoin’s diversifying factor and its high return potential have generated the attention of portfolio managers. In this context, understanding how its volatility is explained is a critical element of investor decision-making. By modeling the volatility of classic assets, nonlinear models such as Generalized Autoregressive Conditional Heteroskedasticity (GARCH) offer suitable results. Therefore, taking GARCH(1,1) as a reference point, the main aim of this study is to model and assess the relationship between the Bitcoin volatility and key financial environment variables through a Conditional Correlation (CC) Multivariate GARCH (MGARCH) approach. For this, several commodities, exchange rates, stock market indices, and company stocks linked to cryptocurrencies have been tested. The results obtained show certain heterogeneity in the fit of the different variables, highlighting the uncorrelation with respect to traditional safe haven assets such as gold and oil. Focusing on the CC-MGARCH model, a better behavior of the dynamic conditional correlation is found compared to the constant

Estudio de la inmunidad innata en pacientes con apnea obstructiva del sueño: Un microambiente favorable para el progreso tumoral

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Medicina, Departamento de Bioquímica. Fecha de lectura: 23-06-2016Obstructive sleep apnea (OSA) is a syndrome characterized by repetitive pauses of breathing induced by a partial or complete collapse of upper airways during sleep. Intermittent hypoxia (IH), a hallmark characteristic of OSA, has been proposed to be a major determinant of cancer development, and patients with OSA are at a higher risk of tumors; however, the relevance of the innate immune system remains undetermined. Herein, we have demonstrated that Monocytes from patients with OSA exhibited tumor-promoting activity and regulated NK cell maturation. The latter’s suppressive capacity was due to the monocyte surface expression of glycoprotein-A repetitions predominant protein, its interaction with the surrounding TGFβ-latency-associated-peptide and subsequently, the release of the active form of TGFβ during IH. In contrast, monocytes isolated from patients treated with continuous positive airway pressure for more than 6 months lacked the tumor-promoting and suppressive capacity of their OSA counterparts. IH modulates the immune response against tumor growth through crosstalk between monocytes and NK cells via TGFβ. The suppression of sleep apneas with restoration of an adequate oxygenation leads to recovery of the normal immune response in patients with OSA, demonstrating the plasticity of innate immune system. The mechanisms linking OSA and cancer have scarcely been explored and, in our knowledge, this is the first study performed on humans to address the pathophysiological pathways that might explain the association between both entitiesLa Apnea Obstructiva del Sueño (OSA, del inglés obstructive sleep apnea) es un síndrome caracterizado por pausas repetitivas en la respiración, inducidas por un colapso parcial o completo de las vías respiratorias superiores durante el sueño. El seguimiento de varias cohortes de pacientes con OSA ha sugerido una alta incidencia de tumores. En este sentido, la hipoxia intermitente, principal característica de OSA, se ha propuesto como el principal factor desencadenante de tumores en estos pacientes. Curiosamente, a pesar del papel crucial que juega el sistema inmune en la génesis y evolución de los procesos tumorales, esto no ha sido explorado en profundidad en esta patología. En este proyecto hemos estudiado diferentes poblaciones del sistema inmune en los pacientes con OSA, así como su interacción. Los monocitos aislados de estos pacientes expresan un conjunto de genes asociados a un fenotipo alternativo también conocido como TAM (del inglés tumor associated macrophages). Estas células exhiben una marcada actividad pro-tumoral siendo capaces de controlar la actividad citotóxica de las células Natural Killer. Esta regulación de la citotoxicidad se da a través de la liberación de la forma activa del Factor de Crecimiento Tumoral β por parte de los monocitos en condiciones de hipoxia intermitente. En el momento que se realiza este estudio, pocos son los reportes que existen sobre los mecanismos celulares y moleculares que explican la incidencia de tumores en pacientes con OSA. Los datos aquí presentados indagan nuevas vías fisiopatológicas en las que la respuesta inmune innata, influenciada por la hipoxia intermitente, cobra gran relevancia en la aparición de un ambiente favorable a la aparición de tumores dentro del contexto OSA. Por otra parte, hemos confirmado que la restauración de la oxigenación adecuada revierte los efectos observados en el sistema inmune, evitando el deterioro de la respuesta inmune antitumora

A System Dynamics Model Approach for Simulating Hyper-inflammation in Different COVID-19 Patient Scenarios

The exceptionally high virulence of COVID-19 and the patients' precondition seem to constitute primary factors in how pro-inflammatory cytokines production evolves during the course of an infection. We present a System Dynamics Model approach for simulating the patient reaction using two key control parameters (i) virulence, which can be moderate or high and (ii) patient precondition, which can be healthy, not so healthy or serious preconditions. In particular, we study the behaviour of Inflammatory (M1) Alveolar Macrophages, IL6 and Active Adaptive Immune system as indicators of the immune system response, together with the COVID viral load over time. The results show that it is possible to build an initial model of the system to explore the behaviour of the key attributes involved in the patient condition, virulence and response. The model suggests aspects that need further study so that it can then assist in choosing the correct immunomodulatory treatment, for instance the regime of application of an Interleukin 6 (IL-6) inhibitor (tocilizumab) that corresponds to the projected immune status of the patients. We introduce machine learning techniques to corroborate aspects of the model and propose that a dynamic model and machine learning techniques could provide a decision support tool to ICU physicians

Estudi, anàlisi i implantació de millores en un taller de fabricació de canonades

Basat en la continua millora dels mètodes de treball i la introducció de nous avanços tecnològics en el dia a dia de les empreses, l’objecte de treball d’aquest projecte es la anàlisis y estudi de millores per a un taller de fabricació industrial de canonades per la seva posterior implantació. En primer lloc, es fa una explicació sobre la construcció de sistemes de transport de fluids o canonades, així com del principal mètode d’unió de les seccions de tub amb els seus components o accessoris presents en una línia. D’aquesta manera, s’explica els principis de la soldadura, la seva classificació i els residus produïts durant el procés. Tot seguit, es presenta el procediment constructiu de la fabricació d’aquets sistemes, on expliquen la preparació per la unió, el procediment de soldadura, amb els diversos processos amb els que realitzem les unions, els tractaments tèrmics post soldadura i finalment, la inspecció de qualitat mitjançant els assajos no destructius. Una vegada definit el procediment, definim el cas base d’estudi on tractarem d’implementar les millores estudiades. Seguidament, es fa referencia a les possibles millores a implementar amb el fi d’optimitzar el procediment constructiu, així com aconseguir una major eficiència de treball. Finalment, amb la anàlisis i l’estudi de les millores, es mostra els diferents aspectes on es tractarà d’implementar les diverses millores estudiades amb el fi de trobar una major eficiència en el procés reduint temps d’espera i variabilitat en la composició de les soldadures

Variables determinantes del drag-flick en jugadoras de hockey hierba

El penalti córner es una de las situaciones de juego más importantes en el hockey hierba. Las mujeres utilizan menos el drag-flick que los hombres. Los objetivos de este estudio fueron describir los parámetros cinemáticos del drag-flick en jugadoras especialistas y hallar las variables determinantes en el rendimiento en este gesto técnico en jugadoras de hockey. Se analizaron quince lanzamientos de cinco lanzadoras con 6 cámaras del sistema de captura automática VICON registrando a 250 Hz. Para la comparación de medias se utilizó un análisis no paramétrico Kruskall Wallis de un factor (sujeto). Aquellos parámetros en los que se hallaron diferencias significativas, se compararon por pares por medio de una U de Mann Whitney. Las jugadoras 1 (22,5 ? 0,9 m/s) y 3 (22,6 ? 0,7 m/s) registraron velocidades de salida de la bola superiores (p < 0,001) a todas las demás jugadoras (19,1 ? 0,7 m/s jugadora 2; 20,5 ? 0,4 m/s jugadora 4 y 19,9 ? 0,4 m/s jugadora 5). La jugadora 1 basa su aceleración final en un doble apoyo largo, con una secuencia de velocidades y una distancia recorrida lo más amplia posible. Sin embargo, jugadora 3 basa su velocidad en la carrera previa, y en una secuencia de movimientos explosiva. Las características individuales de cada jugadora juegan un papel importante en la elección de una estrategia técnica u otra de lanzamiento

An approach to measuring service productivity

A productivity analysis by sector reveals that, traditionally, the levels reached by this variable have been smaller in the service sector than in industrial sector. However, the contributions to know this service production facet have been scarce in spite of the influence of this event on a environment where services are the most important economic activity. This research expects to constitute an introduction for more detailed studies about the unfavourable performance causes of this variable and about the adaptation of the indexes which have been used to measure it.El análisis sectorial de la productividad pone de manifiesto que, tradicionalmente, los niveles alcanzados por esta variable han sido más reducidos en el sector servicios que en el de fabricación de bienes. Sin embargo, a pesar de la importancia que este hecho puede tener en un entorno caracterizado por la creciente terciarización de la actividad económica, las aportaciones al conocimiento de tal aspecto de la producción en aquel sector son escasas. Esta investigación pretende constituir el preámbulo de estudios más pormenorizados sobre las causas del desfavorable comportamiento de dicha magnitud y sobre la adecuación de los índices utilizados para su medida

Seasonality effect analysis and recognition of charging behaviors of electric vehicles: A data science approach

Electric vehicles (EVs) presence in the power grid can bring about pivotal concerns regarding their energy requirements. EVs charging behaviors can be affected by several aspects including socio-economics, psychological, seasonal among others. This work proposes a case study to analyze seasonal effects on charging patterns, using a public real-world based dataset that contains information from the aggregated load of the total charging stations of Boulder, Colorado. Our approach targets to forecast and recognize EVs demand considering seasonal factors. Principal component analysis (PCA) was used to provide a visual representation of the variables and their contribution and the correlation among them. Then, twelve classification models were trained and tested to discriminate among seasons the charging load of electric vehicles. Later, a benchmark stage is presented for regression as well as for classification results. For regression models, examined through Mean Absolute Percentage Error (MAPE) and Root Mean Square Error (RMSE), the random Forest provides better prediction than quasi-Poisson model widely. However, it was observed that for large variations in electric vehicles’ charging load, quasi-Poisson fits better than random forest. For the classification models, evaluated through Accuracy and the Area under the Curve, the Lasso and elastic-net regularized generalized linear (GLMNET) model provided the best global performance with accuracy up to 100% when evaluated on the test dataset. The results of this work offer great insights for enhancing demand response strategies that involve PEV charging regarding charging habits across seasons

Characterization of the cyanobacterium Oscillatoria sp. isolated from extreme sulphureous water from Los Baños de la Hedionda (S Spain)

Los Baños de la Hedionda (Málaga, S Spain) is a natural sulphureous spa (150-200 µM sulphide). Although this high sulphide levels can affect the photosynthetic process, there are numerous photosynthetic microorganisms inhabiting the spa. Among them, we isolated a strain of the cyanobacterium Oscillatoria sp., a genus well known by its tolerance to sulphide. Objectives Firstly, to analyze the photosynthetic characteristics and growth rate of the isolated strain, as well as the effect of the presence of sulphide in both processes. Secondly, to determine the limit of genetic adaptation of this strain to sulphide. Methods The resistance of the isolated strain to sulphide was studied by analyzing the effect of increasing sulphide levels (up to 1600 µM) on photosynthetic performance and growth. The limit of genetic adaptation was explored using an evolutionary experimental design named as ratchet protocol. This design allows discerning the maximum capacity of genetic adaptation of Oscillatoria sp. to the exposure of increasing doses of sulphide Conclusions The strain showed maximum growth rates at 200 µM sulphide although reduced rates can be found up to 800 µM sulphide. A significant increase in resistance was achieved in all derived populations during the ratchet experiment (surviving at sulphide concentrations higher than 2 mM). Moreover, they showed different evolutionary potential to adapt to sulphide, depending on historical contingency.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.Spanish Ministry of Science and Innovation through CGL2014-53682-P project. Predoctoral State Grant from Scientific and Technical Research and Innovation Plan, Spanish Ministry of Economy, Industry and Competitiveness I+D+i ECC/1402/2013, 201

Disentangling mechanisms involved in the adaptation of the cyanobacterium Microcystis aeruginosa to the extreme sulphureous water from Los Baños de la Hedionda (S Spain)

Backgrounds Los Baños de la Hedionda (Málaga, S Spain) is a natural sulphureous spa where sulphide can reach a concentration of 150-200 µM. Although this ion has biocide properties, including inhibition of the photosynthetic process, a rich flora can be found in this extreme environment. Objectives To study the adaptation mechanisms allowing resistance of photosynthetic microorganisms to these sulphureous waters Methods For this purpose, a modified Luria–Delbrück fluctuation analysis was carried out. The adaptation to La Hedionda waters of three different strains of the cyanobacterium Microcystis aeruginosa (Kützing) Kützing (isolated from a non-sulphureous freshwater reservoir) was analyzed in order to find out if it was achieved by a physiological adaptation process (acclimation) or by the selection of rare spontaneous mutations (genetic adaptation). Conclusions Several resistant strains were obtained after 6 weeks of cultivation with La Hedionda waters. The fluctuation analysis showed that genetic adaptation was the phenomenon that allowed resistant M. aeruginosa cells from the three strains to survive, with similar mutation rates in the order of magnitude of 1 mutant resistant cell per 106-107 cell division-1. It could be hypothesized that this cyanobacterium could adapt to sulphureous environment by the selection of favoured mutants.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.Spanish Ministry of Science and Innovation through CGL2014-53682-P project. Predoctoral State Grant from Scientific and Technical Research and Innovation Plan, Spanish Ministry of Economy, Industry and Competitiveness I+D+i ECC/1402/2013, 201

Effect of Biofumigation on Typical Weeds of Strawberry Fields

This research was conducted to evaluate the effect of biofumigation using fresh organic matter on typical weeds present in strawberry fields of southern Spain. Field experiments consisted of biofumigation (BF) treatment over 45 days, at two locations, with hen droppings or horse manure at a dose of 3 kg m-2, alone or in combination with solarization (BF+S) in an experimental randomized block design. Results showed good control of the main weed species, Poa annua, Portulaca oleracea and Lolium rigidum, with comparative populations of the three species under BF/BF+S of 42/4/8, 18/9/12, and 15/0/1 plants m-2 respectively. In addition, 20 seeds each of several weeds were sown inside cloth bags and were submitted to the treatment. The efficiency of biofumigation combined with solarization in the control of P. oleracea, Cynodon dactilon and Echinochloa crus-galli was 77/0, 50/15, and 30/2, as a percentage of germination of control/BF+S. Laboratory experiments consisted of simulating field conditions using a mix of soil, water and different fresh organic matter in a plastic bag, into which different seeds were sown and kept under controlled conditions over 30 days at 27ºC. Fresh organic matter used was whole strawberry plants, horse manure, hen droppings, and combinations of these. Best results were obtained with hen droppings, which showed effective control of Malva parviflora, Medicago sp., E. crus-galli, Amaranthus retroflesuxus, Chenopodium album and P. oleracea, while strawberry residues and horse manure were not useful as herbicides, sometimes even less so than the solarization treatment. Biofumigation with fresh hen droppings and solarization showed promising results in preliminary experiments