Real-time observation of fluctuations at the driven-dissipative Dicke phase transition

We experimentally study the influence of dissipation on the driven Dicke quantum phase transition, realized by coupling external degrees of freedom of a Bose–Einstein condensate to the light field of a high-finesse optical cavity. The cavity provides a natural dissipation channel, which gives rise to vacuum-induced fluctuations and allows us to observe density fluctuations of the gas in real-time. We monitor the divergence of these fluctuations over two orders of magnitude while approaching the phase transition, and observe a behavior that deviates significantly from that expected for a closed system. A correlation analysis of the fluctuations reveals the diverging time scale of the atomic dynamics and allows us to extract a damping rate for the external degree of freedom of the atoms. We find good agreement with our theoretical model including dissipation via both the cavity field and the atomic field. Using a dissipation channel to nondestructively gain information about a quantum many-body system provides a unique path to study the physics of driven-dissipative systems.     

Anxiety and depression in incident stroke survivors and their carers in rural Tanzania: A case-control follow-up study over five years

AimsTo quantify the extent and nature of anxiety and depression in a representative cohort of stroke survivors and their carers in rural Tanzania.DesignA cross-sectional design was used and stroke cases were followed up at 6–60 months post-stroke. Levels of anxiety and depression in stroke survivors, their carers (for physically dependent stroke survivors) and age- and sex-matched controls were assessed using the hospital anxiety and depression (HAD) scale. Other data collected included age, sex, time elapsed since stroke, quality of life, cognitive function, level of disability and socioeconomic status.ResultsLevels of depression seen in our cohort of stroke survivors (53.0%) are high compared to data from the developed and developing world. Anxiety levels (21.6%) are similar to published data. Stroke survivors (n = 58, full data set n = 51) and carers (n = 27) were significantly more anxious than controls (n = 58), whereas levels of depression were similar across all three groups. High stroke survivor HAD scores correlated with lower scores in physical health, psychological health and environment sections of the WHOQOL-Bref. Increased carer anxiety and depression were associated with reduced informant-reported levels of cognitive function in stroke survivors.ConclusionsTo our knowledge this is the first long term study of incident stroke cases in sub-Saharan Africa which has investigated the psychological health of stroke survivors and their carers. Our study highlights the growing need to develop community rehabilitation services in the developing world, which address both physical and psychological morbidity.     

Late presentation with whole limb gangrene following open traumatic hemipelvectomy

Traumatic hemipelvectomy is a rare type of devastating injury with a very high mortality rate and often the result of high energy transfer trauma. Most patients, who survive this injury, do so on the basis of prompt and immediate advanced medical care. Abdominal and pelvic visceral injuries are frequently seen in those cases that survive. We present an unusual case of a 17-year-old patient who survived this injury after presenting 4 days following a motor cycle crash with whole limb gangrene and clinical evidence of septicaemia and without associated abdominal and pelvic visceral injury. She had successful management of her wound and was rehabilitated with axillary crutches and without a prosthetic limb due to financial constraints. The possible mechanism of injury was reviewed and peculiarities of management of this case in our environment were highlighted.