Against the Stream: Ajit Singh and His Battles

This book pays homage to Ajit Singh, economist and intellectual fighter for many causes. It does so through intertwined narratives including, among the major strands, Singh’s life and works, the Faculty of Economics and Politics in Cambridge, and the Punjab and Sikhism — all of which the author manages to weave together with rich prose, fine scholarship and passionate commitment to the subject

Quasi-chemical approximation for polyatomic mixtures

The statistical thermodynamics of binary mixtures of polyatomic species was developed on a generalization in the spirit of the lattice-gas model and the quasi-chemical approximation (QCA). The new theoretical framework is obtained by combining: (i) the exact analytical expression for the partition function of non-interacting mixtures of linear $k$-mers and $l$-mers (species occupying $k$ sites and $l$ sites, respectively) adsorbed in one dimension, and its extension to higher dimensions; and (ii) a generalization of the classical QCA for multicomponent adsorbates and multisite-occupancy adsorption. The process is analyzed through the partial adsorption isotherms corresponding to both species of the mixture. Comparisons with analytical data from Bragg-Williams approximation (BWA) and Monte Carlo simulations are performed in order to test the validity of the theoretical model. Even though a good fitting is obtained from BWA, it is found that QCA provides a more accurate description of the phenomenon of adsorption of interacting polyatomic mixtures.Comment: 27 pages, 8 figure

Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third Edition - Comments and Statistics

The Catalogue, available at the Centre de Donn\'ees Stellaires de Strasbourg, consists of 13573 records concerning the results obtained from different methods for 7778 stars, reported in the literature. The following data are listed for each star: identifications, apparent magnitude, spectral type, apparent diameter in arcsec, absolute radius in solar units, method of determination, reference, remarks. Comments and statistics obtained from CADARS are given.Comment: A&A, in pres

A serious game about recycling rules

Nowadays serious games is one of the biggest existing industries and it is still growing steadily in many sectors. As a major subset of serious games, designing and developing virtual reality applications to support education or promote social behavior has become a promising frontier, because games technology is inexpensive, widely available, fun and entertaining for people of all ages, with several health conditions and different sensory, motor, and cognitive capabilities. In this paper, we provide an overview about a serious game with a perspective of virtual reality for social behavior. The work uses a serious game in an immersive learning environment for recycling learning. In order to improve the user experience the game was developed to work in a cave-like immersive environment, with natural interaction selective alternative. The game includes static and dynamic 3D environments, allowing to share the experience of scenario navigation among users, even geographically distributed.XIII 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

Standard and inverse site percolation of straight rigid rods on triangular lattices: Isotropic and nematic deposition/removal

Numerical simulations and finite-size scaling analysis have been carried out to study standard and inverse percolation of straight rigid rods on triangular lattices. In the case of standard (inverse) percolation, the lattice is initially empty(occupied) and linear $k$-mers ($k$ linear consecutive sites) are randomly and sequentially deposited on(removed from) the lattice, considering an isotropic and nematic scheme. The study is conducted by following the behavior of four critical concentrations with the size $k$, determined for a wide range of $k$ : $(i)$[$(ii)$] standard isotropic[nematic] percolation threshold $\theta_{c,k}$[$\vartheta_{c,k}$], and $(iii)$[$(iv)$] inverse isotropic[nematic] percolation threshold $\theta^i_{c,k}$[$\vartheta^i_{c,k}$]. The obtained results indicate that: $(1)$ $\theta_{c,k}$[$\theta^i_{c,k}$] exhibits a non-monotonous dependence with $k$. It decreases[increases], goes through a minimum[maximum] around $k = 11$, then increases and asymptotically converges towards a definite value for large $k$ $\theta_{c,k \rightarrow \infty}=0.500(2)$[$\theta^i_{c,k \rightarrow \infty}=0.500(1)$]; $(2)$ $\vartheta_{c,k}$[$\vartheta^i_{c,k}$] rapidly increases[decreases] and asymptotically converges towards a definite value for infinitely long $k$-mers $\vartheta_{c,k \rightarrow \infty}=0.5334(6)$[$\vartheta^i_{c,k \rightarrow \infty}=0.4666(6)$]; $(3)$ for both models, the curves of standard and inverse percolation thresholds are symmetric with respect to $\theta = 0.5$. Thus, a complementary property is found $\theta_{c,k} + \theta^i_{c,k} = 1$ (and $\vartheta_{c,k} + \vartheta^i_{c,k} = 1$), which has not been observed in other regular lattices. This condition is analytically validated by using exact enumeration of configurations for small systems; and $(4)$ in all cases, the model presents percolation transition for the whole range of $k$

A serious game about recycling rules

Nowadays serious games is one of the biggest existing industries and it is still growing steadily in many sectors. As a major subset of serious games, designing and developing virtual reality applications to support education or promote social behavior has become a promising frontier, because games technology is inexpensive, widely available, fun and entertaining for people of all ages, with several health conditions and different sensory, motor, and cognitive capabilities. In this paper, we provide an overview about a serious game with a perspective of virtual reality for social behavior. The work uses a serious game in an immersive learning environment for recycling learning. In order to improve the user experience the game was developed to work in a cave-like immersive environment, with natural interaction selective alternative. The game includes static and dynamic 3D environments, allowing to share the experience of scenario navigation among users, even geographically distributed.XIII 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

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