On the 4D generalized Proca action for an Abelian vector field

We summarize previous results on the most general Proca theory in 4 dimensions containing only first-order derivatives in the vector field (second-order at most in the associated St\"uckelberg scalar) and having only three propagating degrees of freedom with dynamics controlled by second-order equations of motion. Discussing the Hessian condition used in previous works, we conjecture that, as in the scalar galileon case, the most complete action contains only a finite number of terms with second-order derivatives of the St\"uckelberg field describing the longitudinal mode, which is in agreement with the results of JCAP 1405, 015 (2014) and Phys. Lett. B 757, 405 (2016) and complements those of JCAP 1602, 004 (2016). We also correct and complete the parity violating sector, obtaining an extra term on top of the arbitrary function of the field $A_\mu$, the Faraday tensor $F_{\mu \nu}$ and its Hodge dual $\tilde{F}_{\mu \nu}$.Comment: LaTeX file in jcappub style, 11 pages, no figures. v2: Minor changes according to the referee requirements. A new parity-violating term in the Lagrangian has been uncovered and the text has been changed accordingly. The conclusions are, essentially, unchanged. v3: Miscellaneous changes. Version to be published in Journal of Cosmology and Astroparticle Physic

On the stability and causality of scalar-vector theories

Various extensions of standard inflationary models have been proposed recently by adding vector fields. Because they are generally motivated by large-scale anomalies, and the possibility of statistical anisotropy of primordial fluctuations, such models require to introduce non-standard couplings between vector fields on the one hand, and either gravity or scalar fields on the other hand. In this article, we study models involving a vector field coupled to a scalar field. We derive restrictive necessary conditions for these models to be both stable (Hamiltonian bounded by below) and causal (hyperbolic equations of motion).Comment: 20 pages, references added, v2 matches published version in JCA

Proyecto de cambio de la estructura organizativa y de gestión administrativa en la empresa "grupo 180"

This investigation was developed due to the need to adopt new tendencies and styles in the administration system of a company, because of the quick globalization in bars and restaurants in Quito and the Valley of Cumbayá, with the purpose of generating new touristic support and service in these territories. Furthermore, it was carried out to assess the need of improving a problem in the change of the organizational structure and management of the company “Grupo 180” to the new staff or any department that is not familiarized with the correct functioning of the company or the department itself. This happens because of previous experiences with other companies dedicated to the same activity, and the lack of interest of familiarizing with the new one. Along with this, the new staff that arrives from other companies does not possess an organizational structure or have experience with similar processes because they come with other mission, vision and philosophy. Every philosophy is different for any company, so the change in the organizational and administrative culture is highly important from every aspect. Each worker and every department must be familiar with this, and even more if there has been an internal change such as an administrative, managerial or technological one. The change of the organizational and administrative management structure is important because the worker will have continuous support and will feel backed by it. The change will be notorious and direct, since I am involved with the company. That way, I’ll be able to experience the accomplishment of the purpose; which is to provide more alternatives or recommendations that allow improving or eliminating the possible impacts that the change of these structures may have on the employability and the treatment of the staff of the company. One of the limitations that this study can have is the assumption that the surveyed staff profoundly knows how important the changes of the organizational and managerial structure in the company “Grupo 180” is. Although it is true that the surveys are directed to the staff of the company, some of them were barely collaborating when doing it, and others were afraid of their answers.El presente trabajo de investigación se realizó por la necesidad de adoptar nuevas tendencias y nuevos estilos de administración debido a la pronta globalización en bares y restaurantes de Quito y del valle de Cumbayá, con el objetivo de generar apoyo turístico y de servicio en los territorios de Quito y del valle de Cumbayá. Además de ver la necesidad de mejorar un problema de cambio de la estructura organizativa y de gestión administrativa en la empresa Grupo 180, para el personal que ingresa a la empresa o hacia algún departamento o no ciego por no conocer el funcionamiento de la empresa o departamento, ya que solo llegan con estudios universitarios previos o de otras empresas que se dedican a lo mismo. Sumado a esto el personal que llega de otras empresas no posee una estructura organizativa o procesos similares donde vienen con otras misiones, visiones y filosofía. Dicha filosofía es diferente en cada empresa, por lo tanto es de suma importancia el cambio en la estructura organizativa y de gestión administrativa de la empresa desde el personal o desde los departamentos donde está el personal recién ingresado, más aún si existe algún cambio interno, ya sea administrativo, gerencial o tecnológico. El cambio de la estructura organizativa y de gestión administrativa es muy importante porque así el trabajador tendrá un apoyo continuo y se sentirá muy respaldado. El cambio será notorio y directo ya que estoy inmerso en la empresa, así podré lograr con el cumplimiento del objetivo el cual es proporcionar más alternativas o recomendaciones que permitan mejorar o eliminar los impactos que puedan tener los cambios en la estructura organizativa y de gestión administrativa en la inserción laboral y un tratamiento laboral de todo el personal de la empresa Grupo 180. Una de las limitaciones que tiene este estudio es asumir que el personal encuestado conoce a profundidad lo importante de los cambios en la estructura organizativa y de gestión administrativa en la empresa Grupo 180, pero si bien es cierto que las encuestas están dirigidas al personal de la empresa, algunos estaban muy poco colaboradores al momento de contestar y otros con temor a sus respuestas