Emergence of turbulence in an oscillating Bose-Einstein condensate

We report on the experimental observation of vortices tangle in an atomic BEC of Rb-87 atoms when an external oscillatory perturbation is introduced in the trap. The vortices tangle configuration is a signature of the presence of a turbulent regime in the cloud. We also show that this turbulent cloud has suppression of the aspect ratio inversion typically observed in quantum degenerate bosonic gases during free expansion. Instead, the cloud expands keeping the ratio between their axis constant. Turbulence in atomic superfluids may constitute an alternative system to investigate decay mechanisms as well as to test fundamental theoretical aspects in this field.Comment: accepted for Phys. Rev. Let

Collective excitation of a Bose-Einstein condensate by modulation of the atomic scattering length

We excite the lowest-lying quadrupole mode of a Bose-Einstein condensate by modulating the atomic scattering length via a Feshbach resonance. Excitation occurs at various modulation frequencies, and resonances located at the natural quadrupole frequency of the condensate and at the first harmonic are observed. We also investigate the amplitude of the excited mode as a function of modulation depth. Numerical simulations based on a variational calculation agree with our experimental results and provide insight into the observed behavior.Comment: Submitted to PR

Off-Duty and Under Arrest: An Exploratory Study of the Arrests of Off-Duty Police Officers, 2005-2017

Presentation at the Annual Meeting of the Academy of Criminal Justice Sciences in National Harbor, MD, on March 17, 2023

Management of anterior vaginal prolapse in South Africa : national survey

LetterThe original publication is available at http://www.samj.org.zaTo the Editor: A national survey was done on the management of anterior vaginal prolapse (AVP) by registered gynaecologists and urologists in South Africa. Of 822 questionnaires posted, 30.2% were returned completed (23.2% from gynaecologists and 7.0% from urologists). The information supplied was anonymous and is probably a true reflection of current practice. Of concern were the 36.3% of respondents who did not use a recognised staging system, a low rate of pre-operative urodynamic investigation by gynaecologists (8.4%) and a high rate of synthetic mesh use by urologists (75.9%), even for primary procedures. This first survey among South African prolapse surgeons provides valuable insight into clinical practice.Publishers’ versio