Gaia FGK Benchmark Stars: Effective temperatures and surface gravities

Large Galactic stellar surveys and new generations of stellar atmosphere models and spectral line formation computations need to be subjected to careful calibration and validation and to benchmark tests. We focus on cool stars and aim at establishing a sample of 34 Gaia FGK Benchmark Stars with a range of different metallicities. The goal was to determine the effective temperature and the surface gravity independently from spectroscopy and atmospheric models as far as possible. Fundamental determinations of Teff and logg were obtained in a systematic way from a compilation of angular diameter measurements and bolometric fluxes, and from a homogeneous mass determination based on stellar evolution models. The derived parameters were compared to recent spectroscopic and photometric determinations and to gravity estimates based on seismic data. Most of the adopted diameter measurements have formal uncertainties around 1%, which translate into uncertainties in effective temperature of 0.5%. The measurements of bolometric flux seem to be accurate to 5% or better, which contributes about 1% or less to the uncertainties in effective temperature. The comparisons of parameter determinations with the literature show in general good agreements with a few exceptions, most notably for the coolest stars and for metal-poor stars. The sample consists of 29 FGK-type stars and 5 M giants. Among the FGK stars, 21 have reliable parameters suitable for testing, validation, or calibration purposes. For four stars, future adjustments of the fundamental Teff are required, and for five stars the logg determination needs to be improved. Future extensions of the sample of Gaia FGK Benchmark Stars are required to fill gaps in parameter space, and we include a list of suggested candidates.Comment: Accepted by A&A; 34 pages (printer format), 14 tables, 13 figures; language correcte

Reaching an equilibrium of prices and holdings of goods through direct buying and selling

The Walras approach to equilibrium focuses on the existence of market prices at which the total demands for goods are matched by the total supplies. Trading activities that might identify such prices by bringing agents together as potential buyers and sellers of a good are characteristically absent, however. Anyway, there is no money to pass from one to the other as ordinarily envisioned in buying and selling. Here a different approach to equilibrium -- what it should mean and how it may be achieved -- is offered as a constructive alternative. Agents operate in an economic environment where adjustments to holdings have been needed in the past, will be needed again in a changed future, and money is familiar for its role in facilitating that. Marginal utility provides relative values of goods for guidance in making incremental adjustments, and with money incorporated into utility and taken as num\`eraire, those values give money price thresholds at which an agent will be willing to buy or sell. Agents in pairs can then look at such individualized thresholds to see whether a trade of some amount of a good for some amount of money may be mutually advantageous in leading to higher levels of utility. Iterative bilateral trades in this most basic sense, if they keep bringing all goods and agents into play, are guaranteed in the limit to reach an equilibrium state in which the agents all agree on prices and, under those prices, have no interest in further adjusting their holdings. The results of computer simulations are provided to illustrate how this works

Activism in today’s rapidly changing media ecology: understanding how environmental and LGBTI+ SMOs created new media practices in Chile [2016-2017]

Today’s media ecology is in constant change due to rapid technological innovation, which is reshaping how social movement organisations (SMOs) use the media. Researchers have coined the concepts of ‘media practices’ and ‘hybrid media ecology’ to describe how activists give new uses to a range of online, offline, mainstream and alternative media practices. They have mostly examined grassroots networks against socioeconomic inequalities in Europe and North America and democratisation uprisings in Arab countries. In contrast, post-materialist movement experiences in South America have received scarce attention. Moreover, existing research on post-materialist movements elsewhere has made broad generalisations about them without engaging in their heterogeneity. This thesis aims to address these gaps by studying Chile as a single country case study and comparing the practices of its environmental and LGBTI+ SMOs. It strives to understand better in what ways and for what reasons SMOs have created new media practices in this context, and why these practices have varied across different SMOs. Based on informed grounded theoretical insights built from semi-structured interviews with SMO representatives, and triangulated with an analysis of documents, websites and social media accounts, the thesis makes three key arguments. First, it finds that nearly all the SMOs included in the study have created new media practices principally to reach more publics with the direct help of their constituents. However, there are some important differences regarding SMOs’ organisational responses to this process. The thesis argues that a large minority of the studied SMOs are innovators that lead the development of new media practices, whereas another large minority emulate and indirectly expand these innovations. There are also a few cases of resistance to the media overall. Innovators seem either committed to inclusiveness as an end in itself or inclined to use citizen involvement as a means to gain political leverage, whereas emulators imitate trends in their field to remain current and appropriate. Thus, key to explaining these different objectives are SMOs’ goals and resources. Finally, the thesis contends that innovation is much higher in the LGBTI+ movement while resistance only exists in the environmental movement. Political divisions, resource inequalities and geographical dispersion explain this. These findings make two important contributions to the literature. First, they show that variations across post-materialist movements should not be overlooked as they indicate the influence of the sociopolitical context on SMOs’ media praxis. Secondly, the concepts of innovation, emulation and resistance help account for heterogeneity in how SMOs react to their media ecology and serve as conceptual tools for further comparative research

KIC~8975515: a fast-rotating (γ\gamma Dor - δ\delta Sct) hybrid star with Rossby modes and a slower δ\delta Sct companion in a long-period orbit

{KIC~8975515 is a \emph{Kepler} double-lined spectroscopic binary system with hybrid pulsations. Two components have similar atmospheric properties (T$_{\rm eff}$ $\sim$ 7400~K), and one of them is a fast rotator ($v\sin i = 162$ versus 32 km/s). Our aim is to study the \emph {Kepler} light curve in great detail in order to determine the frequencies of the pulsations, to search for regular spacing patterns in the Fourier spectrum, if any, and to discuss their origin in the context of binarity and fast rotation. In this paper, we study the properties of the stellar pulsations based on a careful analysis in the low-, intermediate- and high-frequency regions of the Fourier spectrum. This is done by performing repeated frequency-search analyses with successive prewhitenings of all the significant frequencies detected in the spectrum. Moreover, we searched for regular period spacings among the $g$ modes, as well as frequency splitting among the $g$ and $p$ modes. In the low-frequency regime, five regular period spacing patterns including one series of prograde $g$ modes and four series of retrograde $r$ modes were detected. The $r$ modes are well-distributed with respect to the harmonics of the rotational frequency of the fast-rotating star $f_{\rm rot}$ = 1.647 d$^{-1}$. The dominant $g$ mode is $f_{2}$ = 2.37 d$^{-1}$. The strongest p mode, at $f_{1}$ = 13.97 d$^{-1}$, forms a singlet. In the high-frequency region, we identified two multiplets of regularly split $p$ modes with mean frequency spacings of 0.42 d$^{-1}$ and 1.65 d$^{-1}$. We detected some series of retrograde $r$ and prograde $g$ modes as well as two multiplets of $p$ modes with frequency spacings related to the stellar rotation of both components of the twin system KIC~8975515. We identified the fast-rotating component as a hybrid pulsator with $r$ modes and the slowly-rotating component as a $\delta$ Sct pulsator.Comment: Accepted to publish on A \&

Rehabilitación protésica removible y su relación con la calidad de vida del paciente desdentado

Tesis (Cirujano Dentista)La Calidad de Vida relacionada con la salud oral ha sido entre otros establecida como un parámetro para evaluar el tratamiento de una enfermedad. El desdentamiento forma parte de la realidad mundial, y se presenta como uno de los indicadores más importante de la salud oral de adultos, ya que refleja los efectos acumulativos de la salud/enfermedad y factores sociales. La pérdida de dientes compromete la función del sistema estomatognático, disminuyendo la Calidad de Vida del paciente. El tratamiento de estos pacientes en base a prótesis removibles convencionales es ampliamente utilizado. Una rehabilitación removible permite el reemplazo de dientes y estructuras vecinas, preserva la salud de las estructuras remanentes, devuelve estética facial pérdida y función masticatoria, entre otras. Por consiguiente devuelve las funciones orales pérdidas mejorando la salud oral del paciente. El objetivo general que plantea esta investigación es analizar la Calidad de Vida, mediante el Índice OHIP-14, antes y después de la rehabilitación protésica removible. Esta investigación presenta un enfoque cuantitativo y diseño cohorte, donde se observó la variación de la Calidad de Vida según el tipo de rehabilitación protésica realizadas por los alumnos de Cuarto y Quinto año de las cátedras de Prótesis Dentomaxilar y Clínica Integrada del Adulto y Odontogeriatría respectivamente, durante un periodo de 6 meses de seguimiento posterior a la instalación de la rehabilitación protésica

Non-Verbal Communication for a Virtual Reality Interface

The steady growth of technology has allowed to extend all forms of human-computer communication. Since the emergence of more sophisticated interaction devices, Human Computer Interaction (HCI) science has added the issue of Non-Verbal Communication (NVC). Nowadays, there are a lot of applications such as interactive entertainments and virtual reality requiring more natural and intuitive interfaces. Human gestures constitute a great space of actions expressed by the body, face, and/or hands. Hand Gesture is frequently used in people’s daily life, thus it is an alternative form to communicate with computers in an easy way. This paper introduces a real-time hand gesture recognition and tracking system to identify different and dinamic hand postures. In order to improve the user experience, a set of different system functions into a virtual world had been implemented so interaction can be performed by the user through a data glove device.XIV Workshop Computación Gráfica, Imágenes y Visualización (WCGIV).Red de Universidades con Carreras en Informática (RedUNCI

Non-Verbal Communication for a Virtual Reality Interface

The steady growth of technology has allowed to extend all forms of human-computer communication. Since the emergence of more sophisticated interaction devices, Human Computer Interaction (HCI) science has added the issue of Non-Verbal Communication (NVC). Nowadays, there are a lot of applications such as interactive entertainments and virtual reality requiring more natural and intuitive interfaces. Human gestures constitute a great space of actions expressed by the body, face, and/or hands. Hand Gesture is frequently used in people’s daily life, thus it is an alternative form to communicate with computers in an easy way. This paper introduces a real-time hand gesture recognition and tracking system to identify different and dinamic hand postures. In order to improve the user experience, a set of different system functions into a virtual world had been implemented so interaction can be performed by the user through a data glove device.XIV Workshop Computación Gráfica, Imágenes y Visualización (WCGIV).Red de Universidades con Carreras en Informática (RedUNCI

Reality Computing: An end-to-end process for Herpetological Heritage

Documentation of institutional biological collections are essential for scientific studies and conservation of the biodiversity of a region. In particular, preserved specimens require the development of a short- and long-term plan to prevent damage. In this context, the 3D digitisation of this type of documentation provides innovative mechanisms to safeguard the valuable information provided by the collections and at the same time prevent any possible loss of information. At the moment, the potential of laser scanning in model reconstruction is well-known, but developed works using this method for 3D construction reveal a lack of reliable, precise and flexible solutions. Furthermore, visualisation of results is often very useless and does not go beyond web-based applications. This work presents an analysis of 3D modelling using two digitisation techniques: laser scanning and photogrammetry; combined with real time VR and AR visualizations and 3D printing.XVI Workshop Computación Gráfica, Imágenes y Visualización (WCGIV)Red de Universidades con Carreras en Informática (RedUNCI

Reality Computing: An end-to-end process for Herpetological Heritage

Documentation of institutional biological collections are essential for scientific studies and conservation of the biodiversity of a region. In particular, preserved specimens require the development of a short- and long-term plan to prevent damage. In this context, the 3D digitisation of this type of documentation provides innovative mechanisms to safeguard the valuable information provided by the collections and at the same time prevent any possible loss of information. At the moment, the potential of laser scanning in model reconstruction is well-known, but developed works using this method for 3D construction reveal a lack of reliable, precise and flexible solutions. Furthermore, visualisation of results is often very useless and does not go beyond web-based applications. This work presents an analysis of 3D modelling using two digitisation techniques: laser scanning and photogrammetry; combined with real time VR and AR visualizations and 3D printing.XVI Workshop Computación Gráfica, Imágenes y Visualización (WCGIV)Red de Universidades con Carreras en Informática (RedUNCI

Constraints on temporal variation of fundamental constants from GRBs

The formation of a strange or hybrid star from a neutron star progenitor is believed to occur when the central stellar density exceeds a critical value. If the transition from hadron to quark matter is of first order, the event has to release a huge amount of energy in a very short time and we would be able to observe the phenomenon even if it is at cosmological distance far from us; most likely, such violent quark deconfinement would be associated with at least a fraction of the observed gamma ray bursts. If we allow for temporal variations of fundamental constants like $\Lambda_{QCD}$ or $G_N$, we can expect that neutron stars with an initial central density just below the critical value can enter into the region where strange or hybrid stars are the true ground state. From the observed rate of long gamma ray bursts, we are able to deduce the constraint $\dot{G}_N/G_N \lesssim 10^{-17} {\rm yr^{-1}}$, which is about 5 orders of magnitude more stringent than the strongest previous bounds on a possible increasing $G_N$.Comment: 5 pages, no figure. v3: refereed versio