Lagrangian Formalism in Perturbed Nonlinear Klein-Gordon Equations

We develop an alternative approach to study the effect of the generic perturbation (in addition to explicitly considering the loss term) in the nonlinear Klein-Gordon equations. By a change of the variables that cancel the dissipation term we are able to write the Lagrangian density and then, calculate the Lagrangian as a function of collective variables. We use the Lagrangian formalism together with the Rice {\it Ansatz} to derive the equations of motion of the collective coordinates (CCs) for the perturbed sine-Gordon (sG) and $\phi^{4}$ systems. For the $N$ collective coordinates, regardless of the {\it Ansatz} used, we show that, for the nonlinear Klein-Gordon equations, this approach is equivalent to the {\it Generalized Traveling Wave Ansatz} ({\it GTWA})Comment: 9 page

Lepton-number-violating decays of heavy flavors induced by doubly-charged Higgs boson

We study lepton-number-violating (LNV) decays of heavy flavors ($\tau$ lepton and top quark) induced by doubly-charged Higgs boson in the Higgs triplet model. It is found that the branching fractions of LNV $\tau^- \to \ell^{+}M_1^-M_2^-$ decays are highly suppressed compared with the current experimental limits. On the other hand, for LNV top quark decays, the most optimistic branching ratios for $t \to b\ell^{+}\ell^{+}W^{-}$ turn out to be at the level of $\sim 10^{-7} - 10^{-8}$. The observation of these rare top quark decays would be a clear signal of LNV processes, and their non-observation would allow us to constraint the parameters of the Higgs triplet model.Comment: 11 pages, 4 figures, V2: references added, discussion extended, version accepted in Phys. Rev.

McKay correspondence for Landau-Ginzburg models

In this paper we prove an analogue of the McKay correspondence for Landau-Ginzburg models. Our proof is based on the ideas introduced by T. Bridgeland, A. King and M. Reid, which reformulate and generalize the McKay correspondence in the language of derived categories, along with the techniques introduced by J.-C. Chen

What do education students think about their ability to write essays ?

The present study reflects the results obtained from a diagnosis carried out with Education students concerning the writing of academic essays. The objective was to identify the perceptions that Comprehensive Education students have about their ability to write academic essays. A descriptive cross-sectional research study was conducted at a single point in time, and in this case, in a single period or academic cycle, on the subject of written expression. In order to analyze the results from a mathematical-statistical perspective, descriptive statistics were used, in particular the calculation of the mean and the percentage analysis. The results showed that, of the 26 students, 50% rated themselves to have a fair level of essay writing ability. These self-assessment results do not correspond to the quality of the essays written by the students, who demonstrated a low level of essay writing ability. The practice of writing essays is a fundamental activity for the development of written communication at the university level; however, the teaching-learning process must be planned, since this type of writing is one of the most complex skills and has the greatest potential for explaining one’s position and writing creatively. In no way can it be left in the hands of the students; it is necessary to formulate a different learning process that helps the students write essays of better qualityPeer Reviewe

Boundary coupling of Lie algebroid Poisson sigma models and representations up to homotopy

A general form for the boundary coupling of a Lie algebroid Poisson sigma model is proposed. The approach involves using the Batalin-Vilkovisky formalism in the AKSZ geometrical version, to write a BRST-invariant coupling for a representation up to homotopy of the target Lie algebroid or its subalgebroids. These considerations lead to a conjectural description of topological D-branes on generalized complex manifolds, which includes A-branes and B-branes as special cases.Comment: 24 pages, no figures; v2: published versio

Alexander Payne's Nebraska and the return of the grand narratives

This article analyses Alexander Payne’s film Nebraska from the perspective of the paradigm shift produced after the much-debated passing of postmodernism, announced by theorists such as Ihab Hassan or Linda Hutcheon. We shall examine how the lack of grand narratives makes it almost impossible to give structured meanings to the concept of reality. Payne’s project can be viewed as both an allegorical and a physical journey that takes the character to no specific destination in his search to make amends with the harsh reality that, ultimately, spells the end of the American Dream

Obtaining Au thin films in atmosphere of reactive nitrogen through magnetron sputtering

4d and 5d series of the transition metals are used to the obtaining nitrides metallic, due to the synthesis of PtN, AgN and AuN in the last years. Different nitrides are obtained in the Plasma Assisted Physics Vapour Deposition system, due to its ionization energy which is necessary for their formation. In this paper a Magnetron Sputtering system was used to obtain Au thin films on Si wafers in Nitrogen atmosphere. The substrate temperature was varied between 500 to 950°C. The samples obtained at high temperatures (>500°C) show Au, Si and N elements, as it is corroborated in the narrow spectrum obtained for X-Ray Photoelectron Spectroscopy; besides the competition of orientation crystallographic texture between (111) and (311) directions was present in the X-Ray Diffraction analysis to the sample heated at 950°C