Contribution of individual to collective brands

Traditionally, literature estimates the equity of a brand or its extension but it pays little attention to collective brand equity even though collective branding is increasingly used to differentiate the homogenous products of different firms or organizations. We propose an approach that estimates the incremental effect of individual brands (or the contribution of individual brands) on collective brand equity through the various stages of a consumer hierarchical buying choice process in which decisions are nested: “whether to buy”, “what collective brand to buy” and “what individual brand to buy”. This proposal follows the approach of the Random Utility Theory, and it is theoretically argued through the Associative Networks Theory and the cybernetic model of decision making. The empirical analysis carried out in the area of collective brands in Spanish tourism finds a three-stage hierarchical sequence, and estimates the contribution of individual brands to the equity of the collective brands of “Sun, Sea and Sand” and of “World Heritage Cities”.

Fermi-edge singularities in linear and nonlinear ultrafast spectroscopy

We discuss Fermi-edge singularity effects on the linear and nonlinear transient response of an electron gas in a doped semiconductor. We use a bosonization scheme to describe the low-energy excitations, which allows us to compute the time and temperature dependence of the response functions. Coherent control of the energy absorption at resonance is analyzed in the linear regime. It is shown that a phase shift appears in the coherent control oscillations, which is not present in the excitonic case. The nonlinear response is calculated analytically and used to predict that four wave-mixing experiments would present a Fermi-edge singularity when the exciting energy is varied. A new dephasing mechanism is predicted in doped samples that depends linearly on temperature and is produced by the low-energy bosonic excitations in the conduction band.

Valor de marca colectiva: aproximación desde el enfoque de la eficiencia

El objetivo del trabajo consiste en analizar la eficiencia de las empresas que integran una marca colectiva en una industria productora de bienes de experiencia. El supuesto básico es que la marca colectiva tiene un impacto positivo en la eficiencia de las empresas acogidas a la misma, el cual viene explicado porque la reputación colectiva fomenta una inversión eficiente en calidad. Sin embargo, la marca colectiva también puede tener un efecto opuesto sobre los incentivos de una empresa a una inversión en calidad ya que dicha marca puede crear un incentivo a “free ride”. Nuestra propuesta defiende que la interacción entre estos factores opuestos, reputación colectiva y “free ride”, viene moderada por las características de la marca colectiva y de la propia empresa. La metodología aplicada en el contraste de estas hipótesis se apoya en el Análisis Envolvente de Datos para estimar la eficiencia, así como en modelos econométricos para explicar la eficiencia empresarial mediante características de la marca colectiva y de la empresa. Los resultados obtenidos en el ámbito de las bodegas españolas evidencian que las marcas colectivas tienen un impacto positivo sobre la eficiencia, el cual viene moderado por el tamaño de la marca colectiva generando una relación curvilínea en forma de U invertida. Adicionalmente, el volumen de producción de la marca colectiva y el tamaño de las bodegas ejercen un efecto moderador en el impacto del tamaño de la marca colectiva sobre la eficiencia. En general, los resultados ponen de manifiesto la importancia de las marcas colectivas cuando se investigan industrias donde la calidad no es solamente señalizada por una marca típica individual.

Rentabilidad de las empresas vinculadas a las marcas colectivas en el sector vinícola

El objetivo del trabajo consiste en analizar la rentabilidad de las empresas que integran una marca colectiva en el sector vinícola español. El supuesto básico es que la marca colectiva puede explicar la rentabilidad de las bodegas, porque la reputación colectiva es una señal de calidad que reduce las percepciones de riesgo del consumidor. Los resultados obtenidos evidencian que sólo algunas marcas colectivas tienen un efecto positivo en la rentabilidad de las bodegas en relación con las no acogidas a dichas marcas colectivas. Asimismo, la rentabilidad viene asociada positivamente a la diversificación de la bodega en dos o más marcas colectivas.

Electronic properties of transition metal atoms on Cu2N/Cu(100)

We study the nature of spin excitations of individual transition metal atoms (Ti, V, Cr, Mn, Fe, Co, and Ni) deposited on a Cu2N/Cu(100) surface using both spin-polarized density functional theory (DFT) and exact diagonalization of an Anderson model derived from DFT. We use DFT to compare the structural, electronic, and magnetic properties of different transition metal adatoms on the surface. We find that the average occupation of the transition metal d shell, main contributor to the magnetic moment, is not quantized, in contrast with the quantized spin in the model Hamiltonians that successfully describe spin excitations in this system. In order to reconcile these two pictures, we build a zero bandwidth multi-orbital Anderson Hamiltonian for the d shell of the transition metal hybridized with the p orbitals of the adjacent nitrogen atoms, by means of maximally localized Wannier function representation of the DFT Hamiltonian. The exact solutions of this model have quantized total spin, without quantized charge at the d shell. We propose that the quantized spin of the models actually belongs to many-body states with two different charge configurations in the d shell, hybridized with the p orbital of the adjacent nitrogen atoms. This scenario implies that the measured spin excitations are not fully localized at the transition metal.

Política pública en el desarrollo de la juventud rural

La política pública es fundamental para cumplir con el propósito de atender los problemas colectivos a través de la negociación colectiva. En el medio rural se expresa en toda su amplitud, como agenda de formulación, de ejecución y de evaluación ajena a los actores municipales. De esta forma, este artículo tiene como objetivo comprobar los procesos, condiciones y efectos que genera en la población que las recibe, las acepta y se adapta a ellas. Desde el enfoque territorial, se encontró que la política pública y algunos programas dirigidos a los jóvenes, se centran en la juventud urbana; mientras que los jóvenes rurales desconocen las políticas públicas y los programas que son creados o aplicados a ellos. Las instancias de gobierno municipal, registran una falta de atención a los jóvenes, por la escases de estructura administrativa y de recursos económicos, que profundizan la ausencia de coordinación y comunicación entre los tres niveles de gobierno y la sociedad civil; causando que la duplicidad de programas con recursos limitados e insuficientes se sumen a los demás factores que limitan la atención de los jóvenes de la Sierra Norte de Puebla.

Influence of a uniform current on collective magnetization dynamics in a ferromagnetic metal

We discuss the influence of a uniform current j⃗ on the magnetization dynamics of a ferromagnetic metal. We find that the magnon energy ε(q⃗) has a current-induced contribution proportional to q⃗⋅J→, where J→ is the spin current, and predict that collective dynamics will be more strongly damped at finite j⃗. We obtain similar results for models with and without local moment participation in the magnetic order. For transition metal ferromagnets, we estimate that the uniform magnetic state will be destabilized for j≳109A cm-2. We discuss the relationship of this effect to the spin-torque effects that alter magnetization dynamics in inhomogeneous magnetic systems.

Exciton beats in GaAs quantum wells: bosonic representation and collective effects

We discuss light–heavy hole beats observed in transient optical experiments in GaAs quantum wells in terms of a free-boson coherent state model. This approach is compared with descriptions based on few-level representations. Results lead to an interpretation of the beats as due to classical electromagnetic interference. The boson picture correctly describes photon excitation of extended states and accounts for experiments involving coherent control of the exciton density and Rayleigh scattering beating.

Imaging of spin waves in atomically designed nanomagnets

The spin dynamics of all ferromagnetic materials are governed by two types of collective phenomenon: spin waves and domain walls. The fundamental processes underlying these collective modes, such as exchange interactions and magnetic anisotropy, all originate at the atomic scale. However, conventional probing techniques based on neutron1 and photon scattering2 provide high resolution in reciprocal space, and thereby poor spatial resolution. Here we present direct imaging of standing spin waves in individual chains of ferromagnetically coupled S = 2 Fe atoms, assembled one by one on a Cu2N surface using a scanning tunnelling microscope. We are able to map the spin dynamics of these designer nanomagnets with atomic resolution in two complementary ways. First, atom-to-atom variations of the amplitude of the quantized spin-wave excitations are probed using inelastic electron tunnelling spectroscopy. Second, we observe slow stochastic switching between two opposite magnetization states3, 4, whose rate varies strongly depending on the location of the tip along the chain. Our observations, combined with model calculations, reveal that switches of the chain are initiated by a spin-wave excited state that has its antinodes at the edges of the chain, followed by a domain wall shifting through the chain from one end to the other. This approach opens the way towards atomic-scale imaging of other types of spin excitation, such as spinon pairs and fractional end-states5, 6, in engineered spin chains.

Detecting Free Riders in Collective Brands through a Hierarchical Choice Process

Free-riding behaviors exist in tourism and they should be analyzed from a comprehensive perspective; while the literature has mainly focused on free riders operating in a destination, the destinations themselves might also free ride when they are under the umbrella of a collective brand. The objective of this article is to detect potential free-riding destinations by estimating the contribution of the different individual destinations to their collective brands, from the point of view of consumer perception. We argue that these individual contributions can be better understood by reflecting the various stages that tourists follow to reach their final decision. A hierarchical choice process is proposed in which the following choices are nested (not independent): “whether to buy,” “what collective brand to buy,” and “what individual brand to buy.” A Mixed Logit model confirms this sequence, which permits estimation of individual contributions and detection of free riders.