Ground-State Cooling of a Trapped Ion Using Long-Wavelength Radiation.

We demonstrate ground-state cooling of a trapped ion using radio-frequency (rf) radiation. This is a powerful tool for the implementation of quantum operations, where rf or microwave radiation instead of lasers is used for motional quantum state engineering. We measure a mean phonon number of n[over ¯]=0.13(4) after sideband cooling, corresponding to a ground-state occupation probability of 88(7)%. After preparing in the vibrational ground state, we demonstrate motional state engineering by driving Rabi oscillations between the |n=0⟩ and |n=1⟩ Fock states. We also use the ability to ground-state cool to accurately measure the motional heating rate and report a reduction by almost 2 orders of magnitude compared with our previously measured result, which we attribute to carefully eliminating sources of electrical noise in the system.

Should we take a history of prior treatment, and check sputum status at 2-3 months when treating patients for tuberculosis?

SETTING: Pinetown, South Africa (1975-1983). OBJECTIVE: To determine the value of previous treatment history and sputum smear examination at 2-3 months in predicting treatment failure and relapse in tuberculosis patients treated with four drugs given twice weekly for six months under direct observation. DESIGN: Four cohort studies among 562 ambulant adults with culture positive pulmonary tuberculosis, designed to test the effectiveness of isoniazid 600-900 mg, rifampicin 600 mg, pyrazinamide 2-3 g, and streptomycin 1-2 g, given twice weekly. The same drug regimen was given to all patients irrespective of previous treatment history. Therapy was not changed if smears remained positive at 2-3 months. RESULTS: Positive predictive values of a history of previous treatment for a positive smear at 2-3 months (18.3%), treatment failure (5.2%), and relapse (9.4%) were poor. Although patients with positive smears at 2-3 months were more likely to fail therapy than patients with negative smears (relative risk=4.5, 95% Confidence Interval [CI]: 1.6-12.8), positive predictive value for treatment failure was only 12.5%. Although relapse was more frequent in patients with positive smears than those with negative smears (9.7% vs 6.2%; P=0.4), most patients who relapsed had been smear negative at 2-3 months (18/21). CONCLUSION: A four-drug rifampicin-containing regimen can safely be given twice weekly under direct observation to both new and retreatment cases, and the 2-3 month smear examination can safely be omitted.

Directly observed therapy for tuberculosis given twice weekly in the workplace in urban South Africa.

Effective models of delivery of directly observed therapy (DOT) for tuberculosis in resource-poor settings are needed. Intermittent chemotherapy may be an important component of DOT delivered in the community as it means fewer visits to supervisors. There is no published evidence on the efficacy of twice weekly therapy given from the start of treatment without an intensive daily phase. We analysed data from 3 large cohort studies in a migrant, urban workforce in South Africa between 1975 and 1983. All patients received 4 drugs (isoniazid, rifampicin, pyrazinamide and streptomycin) twice weekly under direct observation by a nurse in the workplace. Of 444 patients, 378 (85.1%) completed treatment. Cure could be assessed in 362, and 348 (96.1%, 95% confidence interval 93.7-97.8%) were bacteriologically cured. Sputum status was assessed at 2-3 months in 343 patients and 309 (90.1%) were sputum negative. Eighteen patients relapsed (5.7%; 2.9/100 patient-years of observation). DOT can be effectively delivered to a migrant, urban workforce, and 4-drug therapy given twice weekly under direct observation is efficacious.

An old-style public health perspective of present-day health problems in a black peri-urban area of South Africa.

The public health philosophy of the earliest Medical Officers of Health is as relevant today as it was in the middle of the last century. The social, economic and environmental conditions, together with the historical and cultural background of a community are all worthy of study when assessing health care needs. This paper describes the high-density peri-urban black communities in Natal and KwaZulu that surround the City of Durban, South Africa, and outlines an 'alternative health strategy' that has been developed to meet their specific needs.