Thermal Radiation from a Fluctuating Event Horizon

We consider a pointlike two-level system undergoing uniformly accelerated motion. We evaluate the transition probability for a finite time interval of this system coupled to a massless scalar field near a fluctuating event horizon. Horizon fluctuations are modeled using a random noise which generates light-cone fluctuations. We study the case of centered, stationary and Gaussian random processes. The transition probability of the system is obtained from the positive-frequency Wightman function calculated to one loop order in the noise averaging process. Our results show that the fluctuating horizon modifies the thermal radiation but leaves unchanged the temperature associated with the acceleration.Comment: 8 pages, 3 figure

Boundary effects on radiative processes of two entangled atoms

We analyze radiative processes of a quantum system composed by two identical two-level atoms interacting with a massless scalar field prepared in the vacuum state in the presence of perfect reflecting flat mirrors. We consider that the atoms are prepared in a stationary maximally entangled state. We investigate the spontaneous transitions rates from the entangled states to the collective ground state induced by vacuum fluctuations. In the empty-space case, the spontaneous decay rates can be enhanced or inhibited depending on the specific entangled state and changes with the distance between the atoms. Next, we consider the presence of perfect mirrors and impose Dirichlet boundary conditions on such surfaces. In the presence of a single mirror the transition rate for the symmetric state undergoes a slight reduction, whereas for the antisymmetric state our results indicate a slightly enhancement. Finally, we investigate the effect of multiple reflections by two perfect mirrors on the transition rates.Comment: submitted version to the journa

Short-range Correlations in a CBF description of closed-shell nuclei

The Correlated Basis Function theory (CBF) provides a theoretical framework to treat on the same ground mean-field and short-range correlations. We present, in this report, some recent results obtained using the CBF to describe the ground state properties of finite nuclear systems. Furthermore we show some results for the excited state obtained with a simplified model based on the CBF theory.Comment: 10 latex pages plus 6 uuencoded figure

The relationship of consumer ethnocentrism, purchase intention, and lifestyle in first-generation bicultural ethnic groups

The study analyzed consumer ethnocentrism’s relationship in the first generation Colombian-Canadian bicultural ethnic consumer with purchase intention and lifestyle. One hundred and fifty-eight personal surveys were conducted in Toronto, Canada. It found that ethnocentrism positively influenced the perceptions of Canadian products compared to Colombian products. However, lifestyle was not significantly related to purchase intention. These findings motivate companies to identify their bicultural consumers who may favor products of the host country over most foreign products. It is possible that individuals who incorporate dual ethnic identities can move away from one value system and adopt another; thus, more empirical evidence on the behavior of this type of consumer must be provided, mainly when multinationals compete among one another rather than with their national rivals, with the concept of country of origin being highlighted. Consequently, organizations should know how affiliation with the host country may positively affect on purchase intentions concerning the country of origin

Early Ontogenetic Responses of Six Commercial Chloris Gayana Cultivars to Salinity

Some physiological aspects relevant to pasture establishment under saline conditions were evaluated in six cultivars of Chloris gayana . Two tetraploid cultivars: Boma and Callide, and four diploid ones: Bell, Katambora, Pioneer and a local accession of Pioneer, were analyzed. The effect of salinity on seedling emergence, the number of stolons per plant and frost tolerance were evaluated in the field, while effects on germination, early vegetative growth, regrowth after clipping, ion accumulation and stolon rooting were assessed in the greenhouse. Salinity had a negative effect on seedling emergence. Saline solutions delayed or altogether inhibited germination, but seeds retained viability in 100 and 200 mM NaCl solutions. Growth of all the cultivars was reduced at high salinities, more markedly in cv. Boma, where stolon production was also affected. This cultivar was the most susceptible to frost and had lower Na and higher K accumulation in leaf tissues