Another Look to the Price-Dividend Ratio: A Markov-Switching Approach

This paper analyzes the stationarity of this ratio in the context of a Markov-switching model à la Hamilton (1989) where an asymmetric speed of adjustment is introduced. This particular specification robustly supports a nonlinear reversion process and identifies two relevant episodes: the post-war period from the mid-50’s to the mid-70’s and the so called “90’s boom†period. A three-regime Markov-switching model displays the best regime identification and reveals that only the first part of the 90’s boom (1985-1995) and the post-war period are near-nonstationary states. Interestingly, the last part of the 90’s boom (1996-2000), characterized by a growing price-dividend ratio, is entirely attributed to a regime featuring a highly reverting process.Markov regime-switching, price-dividend ratio stationarity

An Alternative View of the US Price-Dividend Ratio Dynamics

As a necessary condition for the validity of the present value model, the price-dividend ratio must be stationary. However, significant market episodes seem to provide evidence of prices significantly drifting apart from dividends while other episodes show prices anchoring back to dividends. This paper investigates the stationarity of this ratio in the context of a Markov- switching model à la Hamilton (1989) where an asymmetric speed of adjustment towards a unique attractor is introduced. A three-regime model displays the best regime identification and reveals that the first part of the 90’s boom (1985-1995) and the post-war period are characterized by a stationary state featuring a slow reverting process to a relatively high attractor. Interestingly, the latter part of the 90’s boom (1996-2000), characterized by a growing price-dividend ratio, is entirely attributed to a stationary regime featuring a highly reverting process to the attractor. Finally, the post-Lehman Brothers episode of the subprime crisis can be classified into a temporary nonstationary regime.Ministerio de Ciencia e Innovación (Spain), projects SEJ2004-04811/ECON, SEJ2007-66592-C03-01/ECON, ECO2010/16970

Horizontal gene transfer and diverse functional constrains within a common replication-partitioning system in Alphaproteobacteria: the repABC operon

<p>Abstract</p> <p>Background</p> <p>The <it>repABC </it>plasmid family, which is extensively present within <it>Alphaproteobacteria</it>, and some secondary chromosomes of the <it>Rhizobiales </it>have the particular feature that all the elements involved in replication and partitioning reside within one transcriptional unit, the <it>repABC </it>operon. Given the functional interactions among the elements of the <it>repABC </it>operon, and the fact that they all reside in the same operon, a common evolutionary history would be expected if the entire operon had been horizontally transferred. Here, we tested whether there is a common evolutionary history within the <it>repABC </it>operon. We further examined different incompatibility groups in terms of their differentiation and degree of adaptation to their host.</p> <p>Results</p> <p>We did not find a single evolutionary history within the <it>repABC </it>operon. Each protein had a particular phylogeny, horizontal gene transfer events of the individual genes within the operon were detected, and different functional constraints were found within and between the Rep proteins. When different <it>repABC </it>operons coexisted in the same genome, they were well differentiated from one another. Finally, we found different levels of adaptation to the host genome within and between <it>repABC </it>operons coexisting in the same species.</p> <p>Conclusion</p> <p>Horizontal gene transfer with conservation of the <it>repABC </it>operon structure provides a highly dynamic operon in which each member of this operon has its own evolutionary dynamics. In addition, it seems that different incompatibility groups present in the same species have different degrees of adaptation to their host genomes, in proportion to the amount of time the incompatibility group has coexisted with the host genome.</p

Del telecentre de fnals dels noranta a l’espai d’experiències educatives

Des que van sorgir, a fnals dels anys noranta del segle XX, els telecentres han anat evolucionant paral·lelament a l’avenç tecnològic i adaptant-se a les necessitats de la ciutadania pel que fa a l’accés a les TIC i l’adquisició de competències digitals. Fem un repàs de l’evolució d’aquests espais tecnològics

Design and characterization of a pure phase modulator based on TNLC

In this work, we present a complete process to obtain a pure phase modulator based on a twisted nematic liquid crystal display (TNLCD). We first describe a simple technique for measuring the physical parameters of each cell of this device with no ambiguities, and we use them to build a simplified model of the display based on the Jones matrix theory. Then, after selecting a proper optical system for pure phase modulation, an optimal configuration of the system is searched using a numerical algorithm. This procedure drastically reduces the voluminous experimental stage this task normally requires. The presented method is verified through experimental results, finding an excellent agreement between the measurements and the predicted data.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Quantification of high speed actions across a competitive microcycle in professional soccer

The main aim of this study was to compare the high-speed training session (TRs) and competitive match (OMs) demands induced on professional soccer players across an in-season microcycle. Maximum velocity (MV) and the number of actions and distance performed at high (N-HV > 14.4 km·h-1), very high velocity (N-VHV > 19.8 km·h-1) and sprint (N-SP > 25.2 km·h-1), in different distance zones (0–5, 5–15, 15–30, >30 m) were evaluated. Twelve professional soccer players competing within the Spanish 1st Division were the participants of the study. TRs were categorised according to days leading to the match day (MD-5, MD-4, MD-3, MD-1). The results showed significant differences between OMs and TRs across all analysed variables, except for N-HV, N-VHV, and N-SP 15–30m in the comparisons between OMs and MD-4. In addition, N-SP 15–30 m in MD-4 and MD-3 were significantly higher than in MD-1 (ES = 0.87 and 0.80, respectively) without differences in MV highlighting a tapering strategy. To conclude, the current investigation revealed a potential tapering strategy in professional soccer in conjunction to highlighting a way of maintaining MV and high speed actions across low-distance ranges (30 m) across the TRs in order to replicate the velocity peaks occurred in OMs.This study has been funded by the project PPJIA2020.04, of the Precompetitive Research Projects program for Young Researchers of the Own Plan 2020, of the University of Granada

Characterization of sub-channel based Málaga atmospheric optical links with real β parameter

A generalization of the Málaga atmospheric optical communications links treated as a finite number of generalized-K distributed sub-channels is analyzed in terms of outage probability and outage rate when its β parameter belongs to the set of real numbers. To the best of the author’s knowledge, this is the first time that β ∈ ℜ is considered. The new analytical expressions derived in this paper lead to a new physical and more realistic interpretation of atmospheric optical links, especially in terms of performance

Reducción de la brecha digital en Comunidades Vulnerables del Sureste de México

In the XXI century, it is crucial for people belonging to vulnerable and highly marginalized communities have access to telecommunications and have the minimum skills required to use technology, as they are rapidly becoming a tool for transmitting and obtaining information. In today information society, remains a digital divide between those who have access to technological computing resources and Internet, and those who do not, presenting a constant challenge for the development of our people. This paper analyzes the impact of a mixed training program, called: REBREDIG-PJA for the reduction of the digital divide in young and adult people from a vulnerable community in southeastern Mexico, which presents high levels of social marginalization. The results of this study are discussed under the guidelines of the National Development Plan (2013-2018) and the National Digital Strategy (2013) for Mexico and are compared with the guidelines stated in the State Development Plan (2012-2018) for Yucatan.En el siglo XXI, es crucial para las personas pertenecientes a comunidades vulnerables y con alto grado de marginación tener acceso a las telecomunicaciones y poseer las competencias mínimas requeridas para utilizar la tecnología, ya que ésta se está convirtiendo rápidamente en una herramienta para difundir y obtener información. En la sociedad actual de la información, persiste una brecha digital entre quienes tienen acceso a los recursos tecnológicos de cómputo e internet y los que no, presentando un desafío constante para el desarrollo de nuestros pueblos. En este trabajo se analizó el impacto de un programa formativo mixto, denominado: REBREDIG-PJA para la reducción de la brecha digital en personas jóvenes y adultas de una comunidad vulnerable del sureste de México, que presenta altos grados de marginación social. Los resultados de este estudio se discuten bajo los lineamientos del Plan Nacional de Desarrollo (2013-2018) y la Estrategia Digital Nacional, (2013) para México y se comparan con los lineamientos declarados en el Plan Estatal de Desarrollo (2012-2018) para Yucatán

Four-features evaluation of text to speech systems for three social robots

The success of social robotics is directly linked to their ability of interacting with people. Humans possess verbal and non-verbal communication skills, and, therefore, both are essential for social robots to get a natural human&amp;-robot interaction. This work focuses on the first of them since the majority of social robots implement an interaction system endowed with verbal capacities. In order to do this implementation, we must equip social robots with an artificial voice system. In robotics, a Text to Speech (TTS) system is the most common speech synthesizer technique. The performance of a speech synthesizer is mainly evaluated by its similarity to the human voice in relation to its intelligibility and expressiveness. In this paper, we present a comparative study of eight off-the-shelf TTS systems used in social robots. In order to carry out the study, 125 participants evaluated the performance of the following TTS systems: Google, Microsoft, Ivona, Loquendo, Espeak, Pico, AT&amp;T, and Nuance. The evaluation was performed after observing videos where a social robot communicates verbally using one TTS system. The participants completed a questionnaire to rate each TTS system in relation to four features: intelligibility, expressiveness, artificiality, and suitability. In this study, four research questions were posed to determine whether it is possible to present a ranking of TTS systems in relation to each evaluated feature, or, on the contrary, there are no significant differences between them. Our study shows that participants found differences between the TTS systems evaluated in terms of intelligibility, expressiveness, and artificiality. The experiments also indicated that there was a relationship between the physical appearance of the robots (embodiment) and the suitability of TTS systems.The research leading to these results has received funding from the projects: “Development of social robots to help seniors with cognitive impairment (ROBSEN)”, funded by the Ministerio de Economía y Competitividad; “RoboCity2030-DIH-CM”, funded by Comunidad de Madrid and co-funded by Structural Funds of the EU; “Robots Sociales para estimulación física, cognitiva y afectiva de mayores (ROSES)” funded by Agencia Estatal de Investigación (AEI).Publicad

Identification and distance estimation of users and objects by means of electronic beacons in social robotics

Social robots are intended to coexist and to communicate with humans in a natural way. This requires these robots to be able to identify people (and objects) around them to use that information during human-robot dialogs. In this work we present how electronic beacons can benefit the interactions between humans and social robots. In particular, Bluetooth 4.0 Low Energy beacons are presented as the most suitable option, among the up-to-date available technologies. In order to show the advantages of the system during human-robot interaction, first, we present the integration of the information provided by these devices in the robot’s dialog system; and after, a hidden toy hunt game is described as a case study of a scenario where electronic beacons ease the interaction between humans and a social robot.The research leading to these results has received funding from the projects: Development of social robots to help seniors with cognitive impairment (ROBSEN), funded by the Ministerio de Economia y Competitividad (DPI2014-57684-R); and RoboCity2030-III-CM, funded by Comunidad de Madrid and cofunded by Structural Funds of the EU (S2013/MIT-2748)