Observation of Momentum Space Josephson Effects in Weakly Coupled Bose-Einstein Condensates.

The momentum space Josephson effect describes the supercurrent flow between weakly coupled Bose-Einstein condensates (BECs) at two discrete momentum states. Here, we experimentally observe this exotic phenomenon using a BEC with Raman-induced spin-orbit coupling, where the tunneling between two local band minima is implemented by the momentum kick of an additional optical lattice. A sudden quench of the Raman detuning induces coherent spin-momentum oscillations of the BEC, which is analogous to the ac Josephson effect. We observe both plasma and regular Josephson oscillations in different parameter regimes. The experimental results agree well with the theoretical model and numerical simulation and showcase the important role of nonlinear interactions. We also show that the measurement of the Josephson plasma frequency gives the Bogoliubov zero quasimomentum gap, which determines the mass of the corresponding pseudo-Goldstone mode, a long-sought phenomenon in particle physics. The observation of momentum space Josephson physics offers an exciting platform for quantum simulation and sensing utilizing momentum states as a synthetic degree.

Nonexponential Tunneling due to Mean-Field-Induced Swallowtails.

Typically, energy levels change without bifurcating in response to a change of a control parameter. Bifurcations can lead to loops or swallowtails in the energy spectrum. The simplest quantum Hamiltonian that supports swallowtails is a nonlinear 2×2 Hamiltonian with nonzero off-diagonal elements and diagonal elements that depend on the population difference of the two states. This work implements such a Hamiltonian experimentally using ultracold atoms in a moving one-dimensional optical lattice. Self-trapping and nonexponential tunneling probabilities, a hallmark signature of band structures that support swallowtails, are observed. The good agreement between theory and experiment validates the optical lattice system as a powerful platform to study, e.g., Josephson junction physics and superfluidity in ring-shaped geometries.

Prevalence and risk factors for Chlamydia trachomatis, Neisseria gonorrhoeae and Trichomonas vaginalis infection in pregnant women in Papua New Guinea.

OBJECTIVE: To determine the prevalence of, and risk factors associated with, Chlamydia trachomatis, Neisseria gonorrhoeae and Trichomonas vaginalis infection in pregnant women in Madang, Papua New Guinea (PNG). METHODS: A cross-sectional survey was conducted among 400 pregnant women presenting to antenatal clinics. Sociodemographic and behavioural data were collected and real-time PCR diagnostic methods were used to detect the presence of chlamydia, gonorrhoea and trichomonas in self-collected vaginal swabs. The relationships between symptoms, sociodemographic and behavioural factors and infection were assessed. RESULTS: The prevalence of C. trachomatis was 11.1%, N. gonorrhoeae was 9.7% and T. vaginalis was 21.3%. One-third of women (33.7%) had at least one infection. The most common symptom was abdominal pain (48.0%), but only abnormal vaginal discharge was consistently associated with infection (p<0.001). Women diagnosed with vaginal discharge syndrome were more likely to have at least one treatable infection (50.0% (47/94)  vs 26.8% (68/254), p<0.001), yet 59.1% of women with infection would have been missed by the current clinically-based syndromic diagnosis. Risk factors included having a partner at perceived risk of infection, maternal extramarital intercourse, early sexual debut, lack of formal education, urban residence and smoking. 78.8% of women reported never using condoms. CONCLUSIONS: The prevalences of T. vaginalis, C. trachomatis and N. gonorrhoeae were high among pregnant women in coastal PNG. The poor performance of clinically based syndromic diagnosis suggests that alternative strategies are urgently required to improve detection and reduce the burden of sexually transmitted infections and their associated adverse pregnancy outcomes in this population.

Dengue vector control and surveillance during a major outbreak in a coastal Red Sea area in Sudan

An unprecedented dengue outbreak occurred in 2010 in Port Sudan city, Sudan. Dengue incidence was 94 cases per 10 000 observed over 17 epidemiological weeks [total cases = 3 765]. We report here the impact of the vector control response plan to the outbreak, which mainly entailed house inspection and insecticide space spraying. In total 3 048 houses were inspected during vector surveillance and 19 794 larvae and 3 240 pupae of Aedes aegypti were collected. Entomological indices decreased during the period: house index declined from 100% to 16% [F= 57.8, P< 0.001] and pupal/person [P/P] index from 0.77 to 0.10 [F= 3.06, P< 0.01] in weeks 9 and 21 respectively. This decline was accompanied by a decrease in cases from a peak of 341 cases in week 13 to zero in week 29 and the end of the outbreak. There was a significant correlation between the entomological parameters and dengue incidence [R2 = 0.83, F= 23.9,P< 0.001]. Integrated epidemiological and vector surveillance is essential to an effective dengue control programme

Insecticide susceptibility status of the malaria vector Anopheles arabiensis in Khartoum city, Sudan: differences between urban and periurban areas

Vector resistance to insecticides is becoming a major obstacle to malaria prevention measures. A baseline survey was carried out in Khartoum city, Sudan, during September-November 2007, to map the insecticide susceptibility status of Anopheles arabiensis and to examine the correlation with insecticide usage in urban agriculture. Susceptibility tests were conducted in 6 sentinel sites representing urban and periurban strata of the city. Mortality rates and knockdown times were calculated for 8 insecticides on a total of 9820 specimens. An. arabiensis was susceptible to bendiocarb [98.1%], propoxur [100%], fenitrothion [100%], deltamethrin [99.8%] and lambda-cyhalothrin [99.2%]. Susceptibility rates were significantly different between urban and periurban sites for malathion [80.8% vs 56.0%], DDT [99.0% vs 95.0%] and permethrin [98.5% vs 96.3%]. The 50% knockdown times were significantly higher in periurban than urban populations of An. arabiensis for deltamethrin, lambda-cyhalothrin and malathion