General quasi-non-spreading linear three-dimensional wave-packets

We introduce a general approach for generation of sets of three-dimensional quasi-non-spreading wavepackets propagating in linear media, also referred to as linear light bullets. The spectrum of rigorously non-spreading wavepackets in media with anomalous group velocity dispersion is localized on the surface of a sphere, thus drastically restricting the possible wavepacket shapes. However, broadening slightly the spectrum affords the generation of a large variety of quasi-non-spreading distributions featuring complex topologies and shapes in space and time that are of interest in different areas, such as biophysics or nanosurgery. Here we discuss the method and show several illustrative examples of its potential.Comment: 3 pages, 4 figures, to appear in Optics Letter

Making a “malherbario” as an input for the development of competencies for the “Weed control” course.

La falta de insumos para desarrollar el proceso de enseñanza- aprendizaje en la asignatura de Control de malezas, así como el contar con un solo texto guía desactualizado y ciertas restricciones para salidas de campo, motivaron la elaboración de material didáctico de apoyo con materia prima del sector. El proceso innovador se generó con la participación de los estudiantes para la construcción de un herbario propio, al cual se le denominó “malherbario”. Este sirvió para la consolidación de los contenidos y de la información teórica recibida en clase, a través del desarrollo de los tres saberes, y en especial del saber hacer. La acción educativa permitió la generación de competencias específicas que permiten al estudiante ser capaz de producir una respuesta propia que no había sido previamente memorizada.Lack of inputs to carry out the teaching-learning process in the Weed control course as well as having a single outdated guidebook and certain restrictions for field trips led to the creation of teaching support material using raw material of the surrounding areas. The innovative process was fostered with the participation of students for making their own herbarium, called “malherbario”. This served to strengthen the contents and the theoretical information received in class, through the development of three types of knowledge, in particular the know-how. The educational action allowed the development of specific competencies that enable students to be capable of producing their own response that had not been previously memorized

Matter--wave emission in optical lattices: Single particle and collective effects

We introduce a simple set--up corresponding to the matter-wave analogue of impurity atoms embedded in an infinite photonic crystal and interacting with the radiation field. Atoms in a given internal level are trapped in an optical lattice, and play the role of the impurities. Atoms in an untrapped level play the role of the radiation field. The interaction is mediated by means of lasers that couple those levels. By tuning the lasers parameters, it is possible to drive the system through different regimes, and observe phenomena like matter wave superradiance, non-Markovian atom emission, and the appearance of bound atomic states.Comment: 5 pages, 3 figure

Joint characteristic timescales and entropy production analyses for model reduction of combustion systems

The reduction of chemical kinetics describing combustion processes remains one of the major topics in the combustion theory and its applications. Problems concerning the estimation of reaction mechanisms real dimension remain unsolved, this being a critical point in the development of reduction models. In this study, we suggest a combination of local timescale and entropy production analyses to cope with this problem. In particular, the framework of skeletal mechanism is in the focus of the study as a practical and most straightforward implementation strategy for reduced mechanisms. Hydrogen and methane/dimethyl ether reaction mechanisms are considered for illustration and validation purposes. Two skeletal mechanism versions were obtained for methane/dimethyl ether combustion system by varying the tolerance used to identify important reactions in the characteristic timescale analysis of the system. Comparisons of ignition delay times and species profiles calculated with the detailed and the reduced models are presented. The results of the application show transparently the potential of the suggested approach to be automatically implemented for the reduction of large chemical kinetic models

Customer orientation of service employees in family businesses in the hotel sector

The business interactions between front-line employees and customers are crucial to evaluating service quality and for business performance. A gap has been identified in the literature on both customer orientation of service employees (COSE) and family businesses (FBs). These two concepts have never been studied together before. This study presents a concept that develops a theoretical model based on Hennig-Thurau (2004). This model drives research about the COSE and FBs in the hotel sector. The two main contributions are: (1) electronic word-of-mouth (eWOM) is proposed as a consequence of COSE within FBs and (2) a questionnaire has been developed from relevant subscales to measure COSE and the two possible consequences derived from it (Customer Satisfaction and eWOM). A database from Iberic Balance Analysis System (SABI) has been selected to study these variables in the hotel sector, and it will be used in a future empirical study that is expected to provide support for the theory

The influence of digital capabilities on customer orientation of service employees (COSE) and its consequences on customer satisfaction and e-WOM within Family Businesses

Customer relations have become a key matter in services businesses daily activities. Due to the intangibility of services, the employee service performance is what customers perceive as the reflection of the service quality. Due to this fact, the customer orientation of front-line employees, primarily in services industry, plays a crucial role in getting positives/negatives results with regards to customer satisfaction. Customer orientation of service employees (COSE) is a key concept within marketing literature. It has been demonstrated by previous authors the positives effects that has in customer satisfaction and customer retention (Hennig-Thurau. 2004: Morales and Ruiz-Alba, 2018)

Quantum sensors assisted by spontaneous symmetry breaking for detecting very small forces

We propose a quantum-sensing scheme for measuring weak forces based on a symmetry-breaking adiabatic transition in the quantum Rabi model. We show that the system described by the Rabi Hamiltonian can serve as a sensor for extremely weak forces with sensitivity beyond the yoctonewton (yN) per sqrt (Hz) range. We propose an implementation of this sensing protocol using a single trapped ion. A major advantage of our scheme is that the force detection is performed by projective measurement of the population of the spin states at the end of the transition, instead of the far slower phonon number measurement used hitherto

International Management of Customer Orientation

This study investigates the role of customer orientation of service employees (COSE) and its influence on customer satisfaction and on electronic word of mouth (e-WOM), with a focus on international management. An empirical study was conducted amongst hotel customers with a final valid sample of 265 respondents. Digital capabilities have been included in the COSE model for the first time. Findings indicate that digital capabilities have a positive influence on customer satisfaction that is mediated by COSE. This study has also compared differences between international and national firms and also considered family businesses and non-family businesses. Results show that international hotels have a higher level of COSE than national hotels, mainly due to the technical skills of the employees, and the presence of a higher level of COSE in family businesses (FBs) rather than in non-family businesses (NFBs). Some contributions to academia and to international management have been discussed