Conjunctive queries with negation over DL-Lite: a closer look

While conjunctive query (CQ) answering over DL-Lite has been studied extensively, there have been few attempts to analyse CQs with negated atoms. This paper deepens the study of the problem. Answering CQs with safe negation and CQs with a single inequality over DL-Lite with role inclusions is shown to be undecidable, even for a fixed TBox and query.Without role inclusions, answering CQs with one inequality is P-hard and with two inequalities CoNP-hard in data complexity

A model for conservative chaos constructed from multi-component Bose-Einstein condensates with a trap in 2 dimensions

To show a mechanism leading to the breakdown of a particle picture for the multi-component Bose-Einstein condensates(BECs) with a harmonic trap in high dimensions, we investigate the corresponding 2-$d$ nonlinear Schr{\"o}dinger equation (Gross-Pitaevskii equation) with use of a modified variational principle. A molecule of two identical Gaussian wavepackets has two degrees of freedom(DFs), the separation of center-of-masses and the wavepacket width. Without the inter-component interaction(ICI) these DFs show independent regular oscillations with the degenerate eigen-frequencies. The inclusion of ICI strongly mixes these DFs, generating a fat mode that breaks a particle picture, which however can be recovered by introducing a time-periodic ICI with zero average. In case of the molecule of three wavepackets for a three-component BEC, the increase of amplitude of ICI yields a transition from regular to chaotic oscillations in the wavepacket breathing.Comment: 5 pages, 4 figure

Vertex reconstruction algorithms in the PHOBOS experiment at RHIC

The PHOBOS experiment at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory is studying interactions of heavy nuclei at the largest energies available in the laboratory. The high multiplicity of particles created in heavy ion collisions makes precise vertex reconstruction possible using information from a spectrometer and a specialized vertex detector with relatively small acceptances. For lower multiplicity events, a large acceptance, single layer multiplicity detector is used and special algorithms are developed to reconstruct the vertex, resulting in high efficiency at the expense of poorer resolution. The algorithms used in the PHOBOS experiment and their performance are presented.Comment: presented at the Workshop on Tracking In high Multiplicity Environments, TIME0

Isolated vacua in supersymmetric Yang-Mills theories

An explicit proof of the existence of nontrivial vacua in the pure supersymmetric Yang-Mills theories with higher orthogonal SO(N), N>=7 or the G_2 gauge group defined on a 3-torus with periodic boundary conditions is given. Extra vacuum states are separated by an energy barrier from the perturbative vacuum A_i=0 and its gauge copies.Comment: 8 pages, no figures, late

Medición informal del p-valor mediante simulación

Existe un creciente reconocimiento de la importancia de desarrollar el razonamiento inferencial informal (RII) antes de aprender los conceptos formalmente. No obstante todavía hay poca investigación sobre su desarrollo en el aula en el nivel bachillerato (15-18 años). En situaciones informales, la principal dificultad es medir el p-valor de un estadístico, debido que no se tiene la noción de distribución muestral de forma natural. En el presente estudio se analiza el razonamiento de estudiantes de bachillerato para medir el p-valor de un estadístico al usar una aplicación dinámica que crea una distribución muestral empírica mediante la simulación computarizada. Se encuentra que la mayoría de los estudiantes miden el p-valor adecuadamente con ayuda de la simulación, lo que representa un cambio significativo en el RII

Higher order correction to the neutrino self-energy in a medium and its astrophysical applications

We have calculated the 1/M^4 (M the vector boson mass) order correction to the neutrino self-energy in a medium. The possible application of this higher order contribution to the neutrino effective potential is considered in the context of the Early Universe hot plasma and of the cosmological Gamma Ray Burst fireball. We found that, depending on the medium parameters and on the neutrino properties (mixing angle and mass square difference) the resonant oscillation of active to active neutrinos is possible.Comment: 10 pages, revtex style, uses axodraw.sty, 1 figur

Otroacizzia soriae sp. nov., a new Miocene psyllid (Insecta, Hemiptera, Psyllidae) from Dominican amber

new species of the fossil genus Otroacizzia Klimaszewski, 1996 (Hemiptera, Psyllidae) is described as Otroacizzia soriae sp. nov. on the basis of a female specimen. This species is preserved in mid-Miocene amber from La Toca mines, Dominican Republic. The genus Otroacizzia is the most diverse psylloid genus in Dominican amber, with four known species. The new species differs from the three previously known species by the presence of a subapical dark band in the fore wing from the anterior part of the end of vein Rs to the end of vein Cu1b, which has a gap in the middle of the cell c1. Other differences in the fore wing are the presence of a strongly curved vein Cu1b and a cell c1 clearly longer than cell m1. Finally, the antennal segment 3 of the new species is one and a half times longer than segment 4.Se describe una nueva especie del género fósil Otroacizzia Klimaszewski, 1996 (Hemiptera, Psyllidae) a partir de un ejemplar hembra: Otroacizzia soriae sp. nov. Esta especie está conservada en ámbar del Mioceno medio de las minas de La Toca en República Dominicana. Con cuatro especies conocidas, el género Otroacizzia es el género de psiloideo con mayor diversidad en el ámbar dominicano. La nueva especie difiere de las tres especies ya conocidas por la presencia de una banda oscura subapical en el ala anterior desde la parte anterior del final de la vena Rs hasta el final de la vena Cu1b, la cual presenta una discontinuidad en el medio de la celda c1. Otras diferencias en el ala anterior son la presencia de una vena Cu1b fuertemente curvada y una celda c1 claramente más larga que la celda m1. Finalmente, el tercer segmento antenal de la nueva especie es una vez y media más largo que el cuarto segmento

Manage entropy in Architectural Projects: assuming commitments and ordering diversity

It was primary to transfer to the student the importance of his own responsibility on the project, transcending the usual condition of mere academic practice in the school. Their projects are already real actions to transform the reality from the moment in which are the product of a responsible and critical thinking. To the regular development of the Subject of Architectural Projects with theoretical classes and collective corrections in Workshop of Projects, it was incorporated a series of methodologies to activate the individual and collective learning. The project critically acts on city model, proposes an architectural intervention with transformative will and the classroom becomes a social space where individual engagements and collective engagements are added. This dialectic with reality was concluded with the exhibition of projects, which the students explained to the neighbours as the end of the course, first in school and finally in their civic center.Fue primordial transferir al estudiante la importancia de su propia responsabilidad sobre el proyecto, trascendiendo la habitual condición de mera práctica escolar en la Escuela. Sus proyectos son ya verdaderas acciones para transformar la realidad desde el momento mismo en que son el producto de un pensamiento crítico y responsable. Al desarrollo habitual de la Asignatura de Proyectos Arquitectónicos con clases teóricas y correcciones colectivas en Taller de Proyectos se incorporan una serie de metodologías para activar individual y colectivamente el aprendizaje. El proyecto actúa críticamente sobre el modelo de ciudad, propone una intervención arquitectónica con voluntad transformadora y el aula se convierte en un espacio social donde se suman compromisos individuales y compromisos colectivos. Esta dialéctica con la realidad se concluyó con la exposición de los proyectos realizados, que los estudiantes explicaron ante los vecinos del barrio como final de curso, en la Escuela y en su Centro Cívico