Transmission and Reflection of Bose-Einstein Condensates Incident on a Gaussian Potential Barrier

We investigate how Bose-Einstein condensates, whose initial state is either irrotational or contains a single vortex, scatter off a one-dimensional Gaussian potential barrier. We find that for low atom densities the vortex structure within the condensate is maintained during scattering, whereas at medium and high densities, multiple additional vortices can be created by the scattering process, resulting in complex dynamics and disruption of the atom cloud. This disruption originates from two different mechanisms associated respectively with the initial rotation of the atom cloud and the interference between the incident and reflected matter waves. We investigate how the reflection probability depends on the vorticity of the initial state and on the incident velocity of the Bose-Einstein condensate. To interpret our results, we derive a general analytical expression for the reflection coefficient of a rotating Bose-Einstein condensate that scatters off a spatially-varying one-dimensional potential.Comment: 9 pages, 9 figure

Cognitive improvement following repair of a basal encephalocele.

We report the case of a 55-year-old woman presenting with progressive memory impairment secondary to a transsphenoidal encephalocele involving her dominant medial temporal lobe. Her clinical deterioration was accompanied by radiological progression in the encephalocele's size and associated encephalomalacia. Through a temporal craniotomy, her encephalocele was resected and the defect closed. Baseline neuropsychological assessment indicated global cognitive impairment, but post-operatively, she reported improved memory and concentration. Standardized assessment reflected an improvement in perceptual skills and an associated improved recall of a complex figure. This is the first case report to date of a patient's memory improving following treatment of a basal encephalocele

Dynamics of two-component Bose-Einstein condensates in rotating traps

The dynamics of two-component Bose-Einstein condensates in rotating traps is investigated. In the Thomas-Fermi limit, equations of motion are derived showing multiple static solutions for a vortex free condensate. Dynamic stability analysis of these solutions and comparison with Truncated Wigner simulations enables us to identify the regimes for which vortex states will occur. In addition, our analysis predicts centre-of-mass oscillations that are induced by interspecies interactions and affect each component separately. For attractive interspecies interactions, these oscillations lead to a stable symmetry broken state.Comment: v4: more material added. 9 pages, 6 figures v5: figures fixed v6:some rewording v7:fixed figure

Dynamics of two-component Bose-Einstein condensates in rotating traps

The dynamics of two-component Bose-Einstein condensates in rotating traps is investigated. In the Thomas-Fermi limit, equations of motion are derived showing multiple static solutions for a vortex free condensate. Dynamic stability analysis of these solutions and comparison with Truncated Wigner simulations enables us to identify the regimes for which vortex states will occur. In addition, our analysis predicts centre-of-mass oscillations that are induced by interspecies interactions and affect each component separately. For attractive interspecies interactions, these oscillations lead to a stable symmetry broken state.Comment: v4: more material added. 9 pages, 6 figures v5: figures fixed v6:some rewording v7:fixed figure

Collecting Data To Assess SARS Interventions

With cases of severe acute respiratory syndrome (SARS) occurring across geographic regions, data collection on the effectiveness of intervention strategies should be standardized to facilitate analysis. We propose a minimum dataset to capture data needed to examine the basic reproduction rate, case status and criteria, symptoms, and outcomes of SARS

The Effect of Early vs. Normal Calf Weaning on Feedlot Performance and Herd Management: A Cross-Discipline Case Study

A study of early vs. normal weaning of calves concludes that early weaning improves feedlot production efficiency, reducing per day and per pound feedlot production costs. Early weaned steers finished higher thus feedlot profitability was not affected. Early weaning has a positive affect on cow health and pasture utilization rates.Livestock Production/Industries,

Effect of heat treatment on mechanical dissipation in Ta2_2O5_5 coatings

Thermal noise arising from mechanical dissipation in dielectric reflective coatings is expected to critically limit the sensitivity of precision measurement systems such as high-resolution optical spectroscopy, optical frequency standards and future generations of interferometric gravitational wave detectors. We present measurements of the effect of post-deposition heat treatment on the temperature dependence of the mechanical dissipation in ion-beam sputtered tantalum pentoxide between 11\,K and 300\,K. We find the temperature dependence of the dissipation is strongly dependent on the temperature at which the heat treatment was carried out, and we have identified three dissipation peaks occurring at different heat treatment temperatures. At temperatures below 200\,K, the magnitude of the loss was found to increase with higher heat treatment temperatures, indicating that heat treatment is a significant factor in determining the level of coating thermal noise.Comment: accepted Classical and Quantum Gravity 201

Pattern of Reaction Diffusion Front in Laminar Flows

Autocatalytic reaction between reacted and unreacted species may propagate as solitary waves, namely at a constant front velocity and with a stationary concentration profile, resulting from a balance between molecular diffusion and chemical reaction. The effect of advective flow on the autocatalytic reaction between iodate and arsenous acid in cylindrical tubes and Hele-Shaw cells is analyzed experimentally and numerically using lattice BGK simulations. We do observe the existence of solitary waves with concentration profiles exhibiting a cusp and we delineate the eikonal and mixing regimes recently predicted.Comment: 4 pages, 3 figures. This paper report on experiments and simulations in different geometries which test the theory of Boyd Edwards on flow advection of chemical reaction front which just appears in PRL (PRL Vol 89,104501, sept2002