The Nuclear Yukawa Model on a Lattice

We present the results of the quantum field theory approach to nuclear Yukawa model obtained by standard lattice techniques. We have considered the simplest case of two identical fermions interacting via a scalar meson exchange. Calculations have been performed using Wilson fermions in the quenched approximation. We found the existence of a critical coupling constant above which the model cannot be numerically solved. The range of the accessible coupling constants is below the threshold value for producing two-body bound states. Two-body scattering lengths have been obtained and compared to the non relativistic results.Comment: 15 page

Lost and found: the radial quantum number of Laguerre-Gauss modes

We introduce an operator linked with the radial index in the Laguerre-Gauss modes of a two-dimensional harmonic oscillator in cylindrical coordinates. We discuss ladder operators for this variable, and confirm that they obey the commutation relations of the su(1,1) algebra. Using this fact, we examine how basic quantum optical concepts can be recast in terms of radial modes.Comment: Some minor typos fixed

DNA-barcoding Decapoda and Stomatopoda from West-Africa

Codificación del AND de Decápodos y Estomatópodos capturados en Costa Oeste de Áfric

Pelagios and the emerging graph of ancient world data

This paper discusses an emerging cloud of Linked Open Data in the humanities sometimes referred to as the Graph of Ancient World Data (GAWD). It provides historical back- ground to the domain, before gong on to describe the open and decentralised characteristics which have partially characterised its development. This is done principally through the lens of Pelagios, a collaborative initiative led by the authors which connects online historical resources based on common references to places. The benefits and limitations of the approach are evaluated, in particular its low barrier to entry, open architecture and restricted scope. The paper concludes with a number of suggestion for encouraging the adoption of Linked Open Data within other humanities communities and beyond

An integer representation for periodic tilings of the plane by regular polygons

We describe a representation for periodic tilings of the plane by regular polygons. Our approach is to represent explicitly a small subset of seed vertices from which we systematically generate all elements of the tiling by translations. We represent a tiling concretely by a (2+n)×4 integer matrix containing lattice coordinates for two translation vectors and n seed vertices. We discuss several properties of this representation and describe how to exploit the representation elegantly and efficiently for reconstruction, rendering, and automatic crystallographic classification by symmetry detection

Herramienta autor Indesahc para la creación de cursos hipermedia adaptativos

Un elemento fundamental dentro de una plataforma de gestión del aprendizaje (Learning Management Systems, LMS) es la herramienta autor para la producción del material didáctico. En este artículo presentamos un sistema de desarrollo integrado para la creación y evaluación de cursos hipermedia adaptativos accesibles, basados en páginas Web. INDESAHC (Integrated Development System for Adaptive Hypermedia Courses), facilita la introducción del mapa de contenidos del curso, según un modelo del dominio basado en temas, lecciones, conceptos y escenarios tipos, en los cuales se realiza la integración de los archivos de media mediante un entorno visual intuitivo basado en plantillas. Una vez definidas las relaciones entre los temas y los niveles de dificultad de cada lección, se genera el curso hipermedia adaptativo, cuyo diseño final puede ser evaluado a través de una herramienta accesorio llamada EPRules (Educational Prediction Rules). Esta herramienta utiliza algoritmos de minería de datos, para el descubrimiento de información útil para facilitar un proceso de retroalimentación. Se describe además, el modelo didáctico en que se basa INDESAHC y se presenta una metodología eficaz, para evitar los problemas de desorientación y sobrecarga de contenidos en la navegación.In this paper we present an integrated development system for Web Based Adaptive Hypermedia Courses. We have developed an authoring tool called INDESAHC (Integrated Development System for Adaptive Hypermedia Courses) for this purpose. This tool facilitates to the course designer introducing the conceptual map, according to a domain model based on topics, lessons, concepts and learning components. Furthermore, the program allows the integration of media files in the course by means of an intuitive visual environment based on templates. Once defined the relationship among the topics and the difficulty level of each lesson, the user can generate the hypermedia adaptive course. The final design could be evaluated with an accessory tool called EPRules (Educational Prediction Rules). This tool is based on data mining algorithms in order to discover useful information for feedback. We also discuss on how our methodology can avoid the problems of disorientation and cognitive overload

Analysis of nucleotide diversity of NAT2 coding region reveals homogeneity across Native American populations and high intra-population diversity.

N-acetyltransferase 2 (NAT2), an important enzyme in clinical pharmacology, metabolizes antibiotics such as isoniazid and sulfamethoxazole, and catalyzes the transformation of aromatic and heterocyclic amines from the environment and diet into carcinogenic intermediates. Polymorphisms in NAT2 account for variability in the acetylator phenotype and the pharmacokinetics of metabolized drugs. Native Americans, settled in rural areas and large cities of Latin America, are under-represented in pharmacogenetics studies; therefore, we sequenced the coding region of NAT2 in 456 chromosomes from 13 populations from the Americas, and two from Siberia, detecting nine substitutions and 11 haplotypes. Variants *4 (37%), *5B (23%) and *7B (24%) showed high frequencies. Average frequencies of fast, intermediate and slow acetylators across Native Americans were 18, 56 and 25%, respectively. NAT2 intra-population genetic diversity for Native Americans is higher than East Asians and similar to the rest of the world, and NAT2 variants are homogeneously distributed across native populations of the continent

Root-Associated Fungal Communities in Two Populations of the Fully Mycoheterotrophic Plant Arachnitis uniflora Phil. (Corsiaceae) in Southern Chile

The microbiological interactions of the roots of non-photosynthetic plants in South America have been scarcely explored. This study analyzes culturable fungal diversity associated with the mycoheterotrophic plant Arachnitis uniflora Phil. (Corsiaceae) in southern Chile, growing in two different understoreys of native (Nothofagus-dominated) and mixed forest (native, Cupressus sempervirens, and Pinus radiata). Rhizospheric and endophytic fungi were isolated, cultured, and purified to identify microorganisms associated with A. uniflora roots. We showed the different fungi associated with the plant, and that these distributions are influenced by the sampling site. We isolated 410 fungal strains (144 endophytic and 266 from the rhizosphere). We identified 13 operative taxonomical units from plants sampled in the mixed forest, while 15 were from the native forest. Rhizospheric microorganisms were mainly related to Penicillium spp., whereas some pathogenic and saprophytic strains were more frequent inside the roots. Our results have also shown that the fungal strains are weak for phosphate solubilization, but other pathways such as organic acid exudation and indole acetic acid production can be considered as major mechanisms to stimulate plant growth. Our results point to new fungal associates of A. uniflora plants reported in Andean ecosystems, identifying new beneficial endophytic fungi associated with roots of this fully mycoheterotrophic plant.This research was funded by Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT), grant number 1170931 to C.A. (Cesar Arriagada) and Fondo De Fomento al Desarrollo Científico y Tecnológico (FONDECYT), grant number VIU17E0185 to H.H. (Hector Herrera)