Small-amplitude normal modes of a vortex in a trapped Bose-Einstein condensate

We consider a cylindrically symmetric trap containing a small Bose-Einstein condensate with a singly quantized vortex on the axis of symmetry. A time-dependent variational Lagrangian analysis yields the small-amplitude dynamics of the vortex and the condensate, directly determining the equations of motion of the coupled normal modes. As found previously from the Bogoliubov equations, there are two rigid dipole modes and one anomalous mode with a negative frequency when seen in the laboratory frame.Comment: 4 pages, no figures, Revte

From planning to performance: the adaptation process as a determinant of outcomes

Currently, teams require adaptation to deal with work demands successfully. However, research concerning team adaptation should necessarily involve a greater empirical effort in defining under which conditions teams prove more adaptable. This article seeks to contribute to the literature by linking plan formulation, plan execution, and team learning behaviors with team outcomes (i.e., team-adaptation perception and objective performance). Participants formed 142 teams, which were involved in structured-problem solving task (i.e. a simulated management competition). Conditional process analysis was used to test a double-mediated relationship. Results show that, although not all parts of the model are directly associated, there is an indirect link from plan formulation to team outcomes through plan execution and team learning behaviors. Our results support the idea of adaptation as a process, providing four ways in which organizations can elicit changes in teams: increasing plan execution, promoting team learning, improving team adaptive behaviors themselves, and building teams composed of members who demonstrate individual adaptability

Developing biodata for public manager selection purposes: A comparison between fuzzy logic and traditional methods

Biodata have been widely used in personnel selection for a long time, mainly due to their predictive validity in different contexts, low faking, and positive applicant reactions. At the same time, some disadvantages need to be highlighted, with discriminatory content representing a major concern. In order to shed light on these issues, the objectives of the present research are twofold: firstly, we aim to develop biodata items for personnel selection for the provision of managerial positions in Public Administration and, secondly, we aim to test the fuzzy logic method as a valid approach for the development of biodata scales, with a view to choosing the best biodata items in terms of job performance, fairness, and privacy, according with manager and applicant perspectives. Participants assessed 26 items according to traditional and fuzzy rules, resulting in 8 highly effective items. Then, both approaches were compared: fuzzy logic turned out to have similar results as the traditional approach. Finnally, future developments in research an practical implications in the field are suggested. Los datos biográficos (biodata) se han utilizado en la selección de personal durante mucho tiempo debido, principalmente, a su buena validez predictiva en diferentes contextos, a su bajo falseamiento y a las reacciones positivas de los solicitantes de empleo. No obstante, podemos destacar el posible contenido discriminatorio como su principal desventaja. Por tanto, los objetivos de la presente investigación son, en primer lugar, desarrollar empíricamente ítems válidos y justos para la selección de puestos directivos en la Administración Pública y, en segundo lugar, comprobar la utilidad de la lógica difusa en el desarrollo de escalas con biodata para elegir los mejores ítems en términos de desempeño laboral, equidad y privacidad, de acuerdo con las perspectivas de directivos y de solicitantes de empleo. Los participantes en el estudio evaluaron 26 ítems según reglas tradicionales y difusas, y se obtuvieron 8 ítems altamente efectivos. Posteriormente se compararon ambos enfoques: aunque la lógica difusa demostró cierta eficacia, logró resultados similares a los del enfoque tradicional. Finalmente, se proponen futuros desarrollos de investigación e implicaciones prácticas en esta materia

Oscillations of a rapidly rotating annular Bose-Einstein condensate

A time-dependent variational Lagrangian analysis based on the Gross-Pitaevskii energy functional serves to study the dynamics of a metastable giant vortex in a rapidly rotating Bose-Einstein condensate. The resulting oscillation frequencies of the core radius reproduce the trends seen in recent experiments [Engels et al., Phys. Rev. Lett. 90, 170405 (2003)], but the theoretical values are smaller by a factor approximately 0.6-0.8.Comment: 7 pages, revtex

On the inertia of heat

Does heat have inertia? This question is at the core of a long-standing controversy on Eckart's dissipative relativistic hydrodynamics. Here I show that the troublesome inertial term in Eckart's heat flux arises only if one insists on defining thermal diffusivity as a spacetime constant. I argue that this is the most natural definition, and that all confusion disappears if one considers instead the space-dependent comoving diffusivity, in line with the fact that, in the presence of gravity, space is an inhomogeneous medium.Comment: 3 page

Genotypic variation for carotenoids content and chemometric model development for seed quality parameters in wheat

Published online: 19 August 2015Among the groups of naturally occurring pigments, carotenoids serve numerous purposes in plants, including antioxidant activity and protection of the photosynthetic apparatus from the excess of light. Alongside with essential mineral elements, these pigments are well known to have high impact on human health. Therefore, accumulation of carotenoids in wheat grain is an important trait in view to improving nutritional value of cereals. Wheat is one of the major staple foods in Portugal because of its agronomical adaptability and the usage of its flour into various traditional products. In the present investigation, the seeds of ninety-four Old Portuguese wheat cultivars grown over two years were analysed. Significant genetic variability for content of carotenoids was observed in the studied lines. Within the 47 bread wheat genotypes the Yellow Pigment Content (YPC) values varied from 2.7 - 5.8 μg/g and 3.0 - 8.0 μg/g for 2004/2005 and 2009/2010, respectively. On the other hand, during 2004/2005 and 2009/2010, the 47 durum wheat cultivars exhibited the YPC values from 1.1 - 8.0 μg/g and 3.4 - 8.3 μg/g, respectively. In addition, multivariate methods were also explored to assess the wheat grains quality, resorting to FTIR spectroscopy (Figure 1). Preliminary analyses of FTIR spectra clearly revealed differences among the distinct studied genotypes. Thus, in order to find spectroscopical patterns related to carotenoids accumulation and antioxidant activity, efforts are being made to develop a model that will allow the assessment of these parameters through FTIR, in the near-future

Split-merge cycle, fragmented collapse, and vortex disintegration in rotating Bose-Einstein condensates with attractive interactions

The dynamical instabilities and ensuing dynamics of singly- and doubly-quantized vortex states of Bose-Einstein condensates with attractive interactions are investigated using full 3D numerical simulations of the Gross-Pitaevskii equation. With increasing the strength of attractive interactions, a series of dynamical instabilities such as quadrupole, dipole, octupole, and monopole instabilities emerge. The most prominent instability depends on the strength of interactions, the geometry of the trapping potential, and deviations from the axisymmetry due to external perturbations. Singly-quantized vortices split into two clusters and subsequently undergo split-merge cycles in a pancake-shaped trap, whereas the split fragments immediately collapse in a spherical trap. Doubly-quantized vortices are always unstable to disintegration of the vortex core. If we suddenly change the strength of interaction to within a certain range, the vortex splits into three clusters, and one of the clusters collapses after a few split-merge cycles. The vortex split can be observed using a current experimental setup of the MIT group.Comment: 11 pages, 10 figure

Anomalous rotational properties of Bose-Einstein condensates in asymmetric traps

We study the rotational properties of a Bose-Einstein condensate confined in a rotating harmonic trap for different trap anisotropies. Using simple arguments, we derive expressions for the velocity field of the quantum fluid for condensates with or without vortices. While the condensed gas describes open spiraling trajectories, on the frame of reference of the rotating trap the motion of the fluid is against the trap rotation. We also find explicit formulae for the angular momentum and a linear and Thomas-Fermi solutions for the state without vortices. In these two limits we also find an analytic relation between the shape of the cloud and the rotation speed. The predictions are supported by numerical simulations of the mean field Gross-Pitaevskii model.Comment: 4 RevTeX pages, 2 EPS figures; typos fixed, reference adde