Neisseria gonorrhoeae positivity in contacts presenting to a sexual health centre.

BACKGROUND: Concerns regarding antimicrobial resistance and the appropriate use of antibiotics have resulted in many sexual health clinics moving away from the epidemiological treatment of contacts of gonorrhoea. The aim of this study was to inform decision-making regarding patients who are contacts who should be given epidemiological treatment. METHODS: This is a retrospective study of positivity rates of symptomatic and asymptomatic contacts of gonorrhoea who attended the Adelaide Sexual Health Centre from 1 January 2018 to 31 December 2019. Relevant demographic and behavioural characteristics were examined. Non-parametric continuous data were examined as medians and interquartile ranges, and categorical variables were examined as proportions and percentages. Chi-squared tests were used to determine any statistically significant differences in the proportions of participants testing positive to gonorrhoea based on the categorical variables. RESULTS: A total of 402 clients were identified as contacts, of which 124 (30.8%) tested positive for gonorrhoea. Women were statistically more likely to test positive than men (27/56 (48.2%) of women vs 96/345 (27.8%) of men (P =0.002), 0/1 transgender female). From a total of 76 heterosexual men, 14 (18.4%) tested positive as contacts, compared to 82/269 (30.5%) of bisexual/MSM (P =0.038). Of the 214 asymptomatic bisexual/MSM, 55 (25.7%) were positive, 2/56 (3.6%) asymptomatic heterosexual men were positive and 10/29 (34.5%) asymptomatic females were positive for gonorrhoea. CONCLUSION: This study identifies some demographic and behavioural characteristics that may be associated with a higher rate of gonorrhoea positivity as a contact, particularly females and MSM. Careful consideration may be required as to who should be given epidemiological treatment to ensure appropriate and judicious use of antibiotics.

Quantum circuits with many photons on a programmable nanophotonic chip.

Growing interest in quantum computing for practical applications has led to a surge in the availability of programmable machines for executing quantum algorithms1,2. Present-day photonic quantum computers3-7 have been limited either to non-deterministic operation, low photon numbers and rates, or fixed random gate sequences. Here we introduce a full-stack hardware-software system for executing many-photon quantum circuit operations using integrated nanophotonics: a programmable chip, operating at room temperature and interfaced with a fully automated control system. The system enables remote users to execute quantum algorithms that require up to eight modes of strongly squeezed vacuum initialized as two-mode squeezed states in single temporal modes, a fully general and programmable four-mode interferometer, and photon number-resolving readout on all outputs. Detection of multi-photon events with photon numbers and rates exceeding any previous programmable quantum optical demonstration is made possible by strong squeezing and high sampling rates. We verify the non-classicality of the device output, and use the platform to carry out proof-of-principle demonstrations of three quantum algorithms: Gaussian boson sampling, molecular vibronic spectra and graph similarity8. These demonstrations validate the platform as a launchpad for scaling photonic technologies for quantum information processing.

Preindustrial 14CH4 indicates greater anthropogenic fossil CH4 emissions.

Atmospheric methane (CH4) is a potent greenhouse gas, and its mole fraction has more than doubled since the preindustrial era1. Fossil fuel extraction and use are among the largest anthropogenic sources of CH4 emissions, but the precise magnitude of these contributions is a subject of debate2,3. Carbon-14 in CH4 (14CH4) can be used to distinguish between fossil (14C-free) CH4 emissions and contemporaneous biogenic sources; however, poorly constrained direct 14CH4 emissions from nuclear reactors have complicated this approach since the middle of the 20th century4,5. Moreover, the partitioning of total fossil CH4 emissions (presently 172 to 195 teragrams CH4 per year)2,3 between anthropogenic and natural geological sources (such as seeps and mud volcanoes) is under debate; emission inventories suggest that the latter account for about 40 to 60 teragrams CH4 per year6,7. Geological emissions were less than 15.4 teragrams CH4 per year at the end of the Pleistocene, about 11,600 years ago8, but that period is an imperfect analogue for present-day emissions owing to the large terrestrial ice sheet cover, lower sea level and extensive permafrost. Here we use preindustrial-era ice core 14CH4 measurements to show that natural geological CH4 emissions to the atmosphere were about 1.6 teragrams CH4 per year, with a maximum of 5.4 teragrams CH4 per year (95 per cent confidence limit)-an order of magnitude lower than the currently used estimates. This result indicates that anthropogenic fossil CH4 emissions are underestimated by about 38 to 58 teragrams CH4 per year, or about 25 to 40 per cent of recent estimates. Our record highlights the human impact on the atmosphere and climate, provides a firm target for inventories of the global CH4 budget, and will help to inform strategies for targeted emission reductions9,10.