Prevalence and clinical presentation of HIV positive female psychiatric inpatients

Objective: Literature on the prevalence and clinical presentation of South African psychiatric HIV positive patients as well as their management is lacking. This study was performed to investigate these parameters. Method: A prospective study to investigate the prevalence and clinical presentation of HIV positive psychiatric female patients admitted to an acute ward (female psychiatric ward Cecilia Makiwane Hospital, East London Hospital Complex) was undertaken for a one year period from June 2009to May 2010. Additional factors such as demographic profile, associated substance abuse, pre-existing psychiatric disorders and management were also studied.Results: During this one year period 158 female patients were admitted to the acute female psychiatric ward for assessment and treatment. Of these 158 admissions 21 (13%) were HIV positive, but only 19 (12%) consentedto the study. Ten of the 19 HIV positive patients (53%) had an Axis I diagnosis of a psychiatric disorder secondary to HIV, most commonly mood disorder (mania) with psychotic symptoms. Nine of the 19 HIV positive patients (47%) had a pre-existing primary psychiatric diagnosis, most commonly Bipolar Disorder, recent episode mania with psychotic  symptoms. The most common psychotic symptoms were grandiose delusions followed by auditory hallucinations, paranoid delusions and visual hallucinations. The most common mood symptom was euphoria. Substance abuse was uncommon amongst the patients in the study group.Sixteen of the 19 patients (84%) were on antipsychotics, 14 of these 16 patients were on haloperidol. The most commonly used mood stabilizer was sodium valproate. Conclusion: In this study mania with psychotic symptoms was the most common presentation in both the group with a pre-existing primary psychiatric disorder and in the group without a primary psychiatric disorder. The prevalence of HIV positive admitted psychiatric females in this study was 12%. Co-morbid substance abuse was uncommon. Most patients tolerated low doses of typical antipsychotics in combination with a mood stabilizer (valproate being the most common).Keywords: HIV; Female; Psychiatric diagnosis; Hospitalization; South Afric

Maintaining Quantum Coherence in the Presence of Noise through State Monitoring

Unsharp POVM measurements allow the estimation and tracking of quantum wavefunctions in real-time with minimal disruption of the dynamics. Here we demonstrate that high fidelity state monitoring, and hence quantum control, is possible even in the presence of classical dephasing and amplitude noise, by simulating such measurements on a two-level system undergoing Rabi oscillations. Finite estimation fidelity is found to persist indefinitely long after the decoherence times set by the noise fields in the absence of measurement.Comment: 5 pages, 4 figure

High-order noise filtering in nontrivial quantum logic gates

Treating the effects of a time-dependent classical dephasing environment during quantum logic operations poses a theoretical challenge, as the application of non-commuting control operations gives rise to both dephasing and depolarization errors that must be accounted for in order to understand total average error rates. We develop a treatment based on effective Hamiltonian theory that allows us to efficiently model the effect of classical noise on nontrivial single-bit quantum logic operations composed of arbitrary control sequences. We present a general method to calculate the ensemble-averaged entanglement fidelity to arbitrary order in terms of noise filter functions, and provide explicit expressions to fourth order in the noise strength. In the weak noise limit we derive explicit filter functions for a broad class of piecewise-constant control sequences, and use them to study the performance of dynamically corrected gates, yielding good agreement with brute-force numerics.Comment: Revised and expanded to include filter function terms beyond first order in the Magnus expansion. Related manuscripts available from http://www.physics.usyd.edu.au/~mbiercu

Optomechanical trapping and cooling of partially transparent mirrors

We consider the radiative trapping and cooling of a partially transmitting mirror suspended inside an optical cavity, generalizing the case of a perfectly reflecting mirror previously considered [M. Bhattacharya and P. Meystre, Phys. Rev. Lett. \textbf{99}, 073601 (2007)]. This configuration was recently used in an experiment to cool a nanometers-thick membrane [Thompson \textit{et al.}, arXiv:0707.1724v2, 2007]. The self-consistent cavity field modes of this system depend strongly on the position of the middle mirror, leading to important qualitative differences in the radiation pressure effects: in one case, the situation is similar that of a perfectly reflecting middle mirror, with only minor quantitative modifications. In addition, we also identify a range of mirror positions for which the radiation-mirror coupling becomes purely dispersive and the back-action effects that usually lead to cooling are absent, although the mirror can still be optically trapped. The existence of these two regimes leads us to propose a bichromatic scheme that optimizes the cooling and trapping of partially transmissive mirrors.Comment: Submitted to Phys.Rev.

Fluctuations in the formation time of ultracold dimers from fermionic atoms

We investigate the temporal fluctuations characteristic of the formation of molecular dimers from ultracold fermionic atoms via Raman photoassociation. The quantum fluctuations inherent to the initial atomic state result in large fluctuations in the passage time from atoms to molecules. Assuming degeneracy of kinetic energies of atoms in the strong coupling limit we find that a heuristic classical stochastic model yields qualitative agreement with the full quantum treatment in the initial stages of the dynamics. We also show that in contrast to the association of atoms into dimers, the reverse process of dissociation from a condensate of bosonic dimers exhibits little passage time fluctuations. Finally we explore effects due to the non-degeneracy of atomic kinetic energies.Comment: 7 pages, 6 figure