Dynamical Sieve of Eratosthenes

In this document, prime numbers are related as functions over time, mimicking the Sieve of Eratosthenes. For this purpose, the mathematical representation is a uni-dimentional time line depicting the number line for positive natural numbers N, where each number n represents a time t. In the same way as the Eratosthenes' sieve, which iteratively mark as composite the multiples of each prime, starting at each prime. This dynamical prime number function P(s) zero-cross all composite numbers departing from primes, following a linear progression over time.Comment: 9 page

The Kink variety in systems of two coupled scalar fields in two space-time dimensions

In this paper we describe the moduli space of kinks in a class of systems of two coupled real scalar fields in (1+1) Minkowskian space-time. The main feature of the class is the spontaneous breaking of a discrete symmetry of (real) Ginzburg-Landau type that guarantees the existence of kink topological defects.Comment: 12 pages, 5 figures. To appear in Phys. Rev.

Anticipated synchronization in coupled inertia ratchets with time-delayed feedback: a numerical study

We investigate anticipated synchronization between two periodically driven deterministic, dissipative inertia ratchets that are able to exhibit directed transport with a finite velocity. The two ratchets interact through an unidirectional delay coupling: one is acting as a master system while the other one represents the slave system. Each of the two dissipative deterministic ratchets is driven externally by a common periodic force. The delay coupling involves two parameters: the coupling strength and the (positive-valued) delay time. We study the synchronization features for the unbounded, current carrying trajectories of the master and the slave, respectively, for four different strengths of the driving amplitude. These in turn characterize differing phase space dynamics of the transporting ratchet dynamics: regular, intermittent and a chaotic transport regime. We find that the slave ratchet can respond in exactly the same way as the master will respond in the future, thereby anticipating the nonlinear directed transport

Synopsis of a computer program designed to interface a personal computer with the fast data acquisition system of a time-of-flight mass spectrometer

Briefly described are the essential features of a computer program designed to interface a personal computer with the fast, digital data acquisition system of a time-of-flight mass spectrometer. The instrumentation was developed to provide a time-resolved analysis of individual vapor pulses produced by the incidence of a pulsed laser beam on an ablative material. The high repetition rate spectrometer coupled to a fast transient recorder captures complete mass spectra every 20 to 35 microsecs, thereby providing the time resolution needed for the study of this sort of transient event. The program enables the computer to record the large amount of data generated by the system in short time intervals, and it provides the operator the immediate option of presenting the spectral data in several different formats. Furthermore, the system does this with a high degree of automation, including the tasks of mass labeling the spectra and logging pertinent instrumental parameters

Normative and Audience Discourses on Public Service Journalism at a “Critical Juncture”: the Case of TVE in Spain

The concept of journalism, its metatheory and, in particular, public service journalism is regulated by feedback between political models (legal and normative framework), academic precepts and social practices. Scant attention has been paid to date to the impact that these models have on citizens’ discourses, which is especially relevant at “critical junctures”, i.e. periods in which the old institutions are collapsing and require renovation (McChesney, 2007). Hence, this paper addresses the issue in the Spanish context in order to explore the similarities and differences between the academic/legal/normative framework and audience discourses. The former has been studied using documents, reports and legislation, and the latter explored by means of discussion groups with viewers of the newscasts of Televisión Española (TVE)

On supersymmetric Dirac delta interactions

In this paper we construct $\mathcal{N}=2$ supersymmetric (SUSY) quantum mechanics over several configurations of Dirac-$\delta$ potentials from one single delta to a Dirac " comb \rq\rq. We show in detail how the building of supersymmetry on potentials with delta interactions placed in two or more points on the real line requires the inclusion of quasi-square wells. Therefore, the basic ingredient of a supersymmetric Hamiltonian containing two or more Dirac-$\delta$s is the singular potential formed by a Dirac-$\delta$ plus a step ($\theta$) at the same point. In this $\delta/\theta$ SUSY Hamiltonian there is only one singlet ground state of zero energy annihilated by the two supercharges or a doublet of ground states paired by supersymmetry of positive energy depending on the relation between the Dirac well strength and the height of the step potential. We find a scenario of either unbroken supersymmetry with Witten index one or supersymmetry breaking when there is one " bosonic\rq\rq and one " fermionic\rq\rq ground state such that the Witten index is zero. We explain next the different structure of the scattering waves produced by three $\delta/\theta$ potentials with respect to the eigenfunctions arising in the non-SUSY case. In particular, many more bound states paired by supersymmetry exist within the supersymmetric framework compared with the non-SUSY problem. An infinite array of equally spaced $\delta$-interactions of the same strength but alternatively attractive and repulsive are susceptible of being promoted to a ${\cal N}=2$ supersymmetric system...Comment: Submitted to EPJ PLUS; typos corrected and minor changes adde

La disautonomía felina (Síndrome de Key-Gaskell) : caso clínico

Un caso de disautonomía felina en un gato de 10 meses (síndrome de Key-Gaskell). Los síntomas clínicos reflejaron disfunción simpática y parasimpática del sistema nervioso autónomo. E diagnóstico fue basado en la obtención de un grado 4 por el sistema de graduación por síntomas para disautonomía felina propuesto por Sharp (1989). Los síntomas más destacados fueron: midriasis bilateral sin respuesta a la luz, protusión bilateral del tercer párpado, reducción de la secreción lacrimal, regurguitación, retención urinaria, estreñimiento y bradicardia. El animal necesitó ser eutanasiado al cuarto día de hospitalización