Excited-state quantum phase transitions in a two-fluid Lipkin model

Background: Composed systems have became of great interest in the framework of the ground state quantum phase transitions (QPTs) and many of their properties have been studied in detail. However, in these systems the study of the so called excited-state quantum phase transitions (ESQPTs) have not received so much attention. Purpose: A quantum analysis of the ESQPTs in the two-fluid Lipkin model is presented in this work. The study is performed through the Hamiltonian diagonalization for selected values of the control parameters in order to cover the most interesting regions of the system phase diagram. [Method:] A Hamiltonian that resembles the consistent-Q Hamiltonian of the interacting boson model (IBM) is diagonalized for selected values of the parameters and properties such as the density of states, the Peres lattices, the nearest-neighbor spacing distribution, and the participation ratio are analyzed. Results: An overview of the spectrum of the two-fluid Lipkin model for selected positions in the phase diagram has been obtained. The location of the excited-state quantum phase transition can be easily singled out with the Peres lattice, with the nearest-neighbor spacing distribution, with Poincar\'e sections or with the participation ratio. Conclusions: This study completes the analysis of QPTs for the two-fluid Lipkin model, extending the previous study to excited states. The ESQPT signatures in composed systems behave in the same way as in single ones, although the evidences of their presence can be sometimes blurred. The Peres lattice turns out to be a convenient tool to look into the position of the ESQPT and to define the concept of phase in the excited states realm

Performing Immobility in Contemporary Palestinian Theatre

After the Oslo Accords (1993-1995), Palestine has witnessed the consolidation of a closure regime that limits the freedom of movement of its population. This system has located Palestine in a marginal position within the global patterns of mobility and has had an impact in the internal social dynamics and in artistic representation. Theatre can portray, represent and challenge this process of immobilization. Through the analysis of the play Confinement, produced by Al-Harah in 2010, this paper will analyze how theatre can open new spaces of representation which allows alternative narratives within the intricate panorama of the Israeli occupation

Non-Ergodicity of the 1D Heisenberg Model

The relevance of zero-energy functions, coming from zero-energy modes and present in the structure of bosonic Green's functions, is often underestimated. Usually, their values are fixed by assuming the ergodicity of the dynamics, but it can be shown that this is not always correct. As the zero-energy functions are connected to fundamental response properties of the system under analysis (specific heat, compressibility, susceptibility, etc.), their correct determination is not an irrelevant issue. In this paper we present some results regarding the zero-energy functions for the Heisenberg chain of spin-1/2 with periodic boundary conditions as functions of the number of sites, temperature and magnetic field. Calculations are pursued for finite chains, using equations of motion, exact diagonalization and Lanczos technique, and the extrapolation to thermodynamic limit is studied.Comment: 4 pages, 2 figure

Cell Receptors for Influenza a Viruses and the Innate Immune Response

The interaction of the hemagglutinin (HA) of the influenza A viruses (IAV) with the cell surface is a key factor for entry of the virus and productive infection of the cell. This glycoprotein has affinity for sialic acids (SA), and different strains present specificity for SA bound through α2,3 or α2,6 linkages to the underlying sugar chain, which is usually related with host and cell tropism. Nucleic acid recognizing receptors (mainly RIG-I and Toll-like receptors) are the most extensively studied pattern recognition receptors for IAV. However, due to the ability of the HA of avian, swine, or human influenza viruses to bind differently linked SA and also to the high levels and variability of glycosylations of their major virion glycoprotein components, HA and NA, IAV interacting proteins on the cell surface could also play an important role in initiating different signaling pathways to elicit the immune response in infected cells. But, at present, these processes are not well understood. In this mini-review we discuss how the interactions of IAV with cell surface receptors on immune cells might be important for the induction of specific innate immune responses and as a result, for pathogenicity in humans

Model and neural control of the depth of anesthesia during surgery

At present, the experimentation of anesthetic drugs on patients requires a regulation protocol, and the response of each patient to several doses of entry drug must be well known. Therefore, the development of pharmacological dose control systems is a promising field of research in anesthesiology. In this paper it has been developed a non-linear compartmental pharmacokinetic-pharmacodynamical model which describes the anesthesia depth effect on a sufficiently reliable way over a set of patients with the depth effect quantified by the Bi-Spectral Index. Afterwards, an Artificial Neural Network (ANN) predictive controller has been designed based on the depth of anesthesia model so as to keep the patient on the optimum condition while he undergoes surgical treatment. For the purpose of quantifying the efficiency of the neural predictive controller, a classical proportional-integral-derivative controller has also been developed to compare both strategies. Results show the superior performance of predictive neural controller during Bi- Spectral Index reference tracking.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

The Prediction of Training Proficiency in Firefighters: A Study of Predictive Validity in Spain

The present study provides results of criterion validity in the selection of firefighters in Spain. The predictors were cognitive skills, job knowledge, and physical aptitudes, and the criterion was training proficiency. The process involves 639 candidates, but only 44 complete successfully the selection process. Our results support previous evidence showing that general cognitive ability is the best predictor of training proficiency, with an operational validity of .57. With respect to the other predictors, job knowledge presented an operational validity of .55 and physical tests of .49. In addition, multiple regression analysis showed that cognitive aptitude explains 33% of the variance, but when physical aptitudes are included the explained variance increases to 50%. If we also add job knowledge, explained variance increases to 55%. Our study offers recent results of criterion validity in a barely investigated job, gathered in a country other than the one where prior research had been carried out. Este estudio ofrece resultados de la validez de criterio en la selección de bomberos en España. Los predictores fueron las aptitudes cognitivas, el conocimiento del puesto y las aptitudes físicas, siendo el criterio el aprovechamiento de la formación. El proceso comenzó con 639 candidatos, de los cuales solamente 44 superaron la selección. Nuestros resultados apoyan la evidencia previa, mostrando que la aptitud cognitiva general es el mejor predictor, con una validez operativa de .57, seguido del conocimiento del puesto con .55 y las pruebas físicas con .49. Además, el análisis de regresión múltiple mostró que la aptitud cognitiva explica un 33% de la varianza, que se incrementa hasta el 50% al incluir pruebas físicas y hasta el 55% si además se añade conocimiento del puesto. Estos resultados resultan especialmente interesantes al haber sido obtenidos en un país diferente al de las principales investigaciones de referencia (i.e., Estados Unidos de América)