Deeply Virtual Compton Scattering Cross Section at High Bjorken x_{B}

We report high-precision measurements of the deeply virtual Compton scattering (DVCS) cross section at high values of the Bjorken variable x_{B}. DVCS is sensitive to the generalized parton distributions of the nucleon, which provide a three-dimensional description of its internal constituents. Using the exact analytic expression of the DVCS cross section for all possible polarization states of the initial and final electron and nucleon, and final state photon, we present the first experimental extraction of all four helicity-conserving Compton form factors (CFFs) of the nucleon as a function of x_{B}, while systematically including helicity flip amplitudes. In particular, the high accuracy of the present data demonstrates sensitivity to some very poorly known CFFs.

Form Factors and Two-Photon Exchange in High-Energy Elastic Electron-Proton Scattering

We present new precision measurements of the elastic electron-proton scattering cross section for momentum transfer (Q^{2}) up to 15.75  (GeV/c)^{2}. Combined with existing data, these provide an improved extraction of the proton magnetic form factor at high Q^{2} and double the range over which a longitudinal or transverse separation of the cross section can be performed. The difference between our results and polarization data agrees with that observed at lower Q^{2} and attributed to hard two-photon exchange (TPE) effects, extending to 8  (GeV/c)^{2} the range of Q^{2} for which a discrepancy is established at >95% confidence. We use the discrepancy to quantify the size of TPE contributions needed to explain the cross section at high Q^{2}.

TB testing in HIV-positive patients prior to antiretroviral treatment

BACKGROUND: TB diagnosis in patients with HIV is challenging due to the lower sensitivities across tests. Molecular tests are preferred and the Xpert^® MTB/RIF assay has limitations in lower-income settings. We evaluated the performance of loop-mediated isothermal amplification (LAMP) and the lipoarabinomannan (LAM) test in HIV-positive, ART-naïve clinic patients.METHODS: A total of 783 eligible patients were enrolled; three spot sputum samples of 646 patients were tested using TB-LAMP, Xpert, smear microscopy and culture, while 649 patients had TB-LAM testing. Sensitivity, specificity, and negative and positive predictive values were estimated with 95% confidence intervals.RESULTS: Sensitivities for smear microscopy, TB-LAMP and Xpert were respectively 50%, 63% and 74% compared to culture, with specificities of respectively 99.2%, 98.5% and 97.5%. An additional eight were positive on TB-LAM alone. Seventy TB patients (9%) were detected using standard-of-care testing, an additional 27 (3%) were detected using study testing. Treatment was initiated in 57/70 (81%) clinic patients, but only in 56% (57/97) of all those with positive TB tests; 4/8 multidrug-resistant samples were detected using Xpert.CONCLUSION: TB diagnostics continue to miss cases in this high-burden setting. TB-LAMP was more sensitive than smear microscopy, and if followed by culture and drug susceptibility testing as required, can diagnose TB in HIV-positive patients. TB-LAM is a useful add-in test and both tests at the point-of-care would maximise yield.

Girl Champ in eSwatini: A Strategic Marketing Campaign to Promote Demand for Sexual and Reproductive Health Services Among Young Women

Efforts to engage adolescent girls and young women (AGYW) in HIV services have struggled, in part, due to limited awareness of services and stigma. Strategic marketing is a promising approach, but the impact on youth behavior change is unclear. We report findings from a mixed methods evaluation of the Girl Champ campaign, designed to generate demand for sexual and reproductive services among AGYW, and piloted in three clinics in the Manzini region of eSwatini. We analyzed and integrated data from longitudinal, clinic-level databases on health service utilization among AGYW before and after the pilot, qualitative interviews with stakeholders responsible for the implementation of the pilot, and participant feedback surveys from attendees of Girl Champ events. Girl Champ was well received by most stakeholders based on event attendance and participant feedback, and associated with longitudinal improvements in demand for HIV services. Findings can inform future HIV demand creation interventions for youth.

Deep Exclusive Electroproduction of π^{0} at High Q^{2} in the Quark Valence Regime

We report measurements of the exclusive neutral pion electroproduction cross section off protons at large values of x_{B} (0.36, 0.48, and 0.60) and Q^{2} (3.1 to 8.4  GeV^{2}) obtained from Jefferson Lab Hall A experiment E12-06-014. The corresponding structure functions dσ_{T}/dt+εdσ_{L}/dt, dσ_{TT}/dt, dσ_{LT}/dt, and dσ_{LT^{'}}/dt are extracted as a function of the proton momentum transfer t-t_{min}. The results suggest the amplitude for transversely polarized virtual photons continues to dominate the cross section throughout this kinematic range. The data are well described by calculations based on transversity generalized parton distributions coupled to a helicity flip distribution amplitude of the pion, thus providing a unique way to probe the structure of the nucleon.

Ruling out Color Transparency in Quasielastic ^{12}C(e,e^{'}p) up to Q^{2} of 14.2 (GeV/c)^{2}

Quasielastic ^{12}C(e,e^{'}p) scattering was measured at spacelike 4-momentum transfer squared Q^{2}=8, 9.4, 11.4, and 14.2  (GeV/c)^{2}, the highest ever achieved to date. Nuclear transparency for this reaction was extracted by comparing the measured yield to that expected from a plane-wave impulse approximation calculation without any final state interactions. The measured transparency was consistent with no Q^{2} dependence, up to proton momenta of 8.5  GeV/c, ruling out the quantum chromodynamics effect of color transparency at the measured Q^{2} scales in exclusive (e,e^{'}p) reactions. These results impose strict constraints on models of color transparency for protons.

Probing the Deuteron at Very Large Internal Momenta

We measure ^{2}H(e,e^{'}p)n cross sections at 4-momentum transfers of Q^{2}=4.5±0.5  (GeV/c)^{2} over a range of neutron recoil momenta p_{r}, reaching up to ∼1.0  GeV/c. We obtain data at fixed neutron recoil angles θ_{nq}=35°, 45°, and 75° with respect to the 3-momentum transfer q[over →]. The new data agree well with previous data, which reached p_{r}∼500  MeV/c. At θ_{nq}=35° and 45°, final state interactions, meson exchange currents, and isobar currents are suppressed and the plane wave impulse approximation provides the dominant cross section contribution. We compare the new data to recent theoretical calculations, where we observe a significant discrepancy for recoil momenta p_{r}>700  MeV/c.

Neuromonitoring

Neuromonitoring is used during surgery to assess the functional integrity of the brain, brain stem, spinal cord, or peripheral nerves. The aim of monitoring is to prevent permanent damage by early intervention when changes are detected in the monitor. Neuromonitoring is also used to map areas of the nervous system in order to guide management in some cases. The best neuromonitor remains the awake patient. In the conscious state, the function of individual parts of the nervous system and the complex interactions of its different parts can be assessed more accurately. However, most surgical procedures involving the nervous system require general anaesthesia. Procedures that require neuromonitoring can have changes in their monitored parameters corrected by modifying the surgical approach or by having the anaesthesiologist manipulate the parameters under their control. An ideal neuromonitor would be one that is specific for the parameter of interest, and gives reliable, reproducible, or continuous results.

Spinal cord pathways

The spinal cord is the primary pathway of communication between the brain and peripheral nervous system. Knowledge of the spinal cord anatomy and recognition of typical common spinal cord syndromes are important as many of these diseases have a predilection for targeting specific areas or tracts within the spinal cord.

Who are the male partners of adolescent girls and young women in Swaziland? Analysis of survey data from community venues across 19 DREAMS districts

BACKGROUND

Adolescent girls and young women (AGYW, ages 15-24) are at high risk of HIV in Swaziland. Understanding more about their male sexual partners can inform HIV prevention efforts for both.

METHODS

Using the PLACE methodology across all 19 DREAMS implementation districts, 843 men ages 20-34 were surveyed between December 2016-February 2017. Surveys were conducted at 182 venues identified by community informants as places where AGYW and men meet/socialize. Descriptive and multivariate analyses examined characteristics and risk behaviors of male partners of AGYW.

RESULTS

Men's average age was 25.7. Sixty-three percent reported female partners ages 15-19, and 70% reported partners ages 20-24 in the last year; of those, 12% and 11% respectively had five or more such partners. Among the 568 male partners of AGYW, 36% reported consistent condom use with their current/last partner. Forty-two percent reported testing for HIV in the last year; 6% were HIV-positive, and of those, 97% were currently on treatment. One-third (37%) reported being circumcised; among uncircumcised, 81% were not considering it. In multivariate analyses, men who reported three or more AGYW partners in the last year were more likely to be HIV-positive (aOR 3.2, 95% CI 1.1,8.8). Men were also less likely to disclose their HIV status to adolescent versus older partners (aOR 0.6, 95% CI 0.4,0.9) and partners more than 5 years younger than themselves (aOR 0.6, 95% CI 0.4,0.9). Results also revealed relatively high unemployment and mobility, substantial financial responsibilities, and periodic homelessness.

CONCLUSIONS

Most men identified through community venues reported relationships with AGYW, and these relationships demonstrated substantial HIV risk. Challenging life circumstances suggest structural factors may underlie some risk behaviors. Engaging men in HIV prevention and targeted health services is critical, and informant-identified community venues are promising intervention sites to reach high-risk male partners of AGYW.

Detecting Mycobacterium tuberculosis using the loop-mediated isothermal amplification test in South Africa

SETTING

In South Africa, KwaZulu-Natal is the epicentre of the human immunodeficiency virus (HIV) epidemic, where approximately 70% of people with tuberculosis (TB) are co-infected with HIV. Undiagnosed TB contributes to high mortality in HIV-infected patients. Delays in diagnosing TB and treatment initiation result in prolonged transmission and increased infectiousness.

OBJECTIVE

To evaluate the LoopampTM MTBC Detection kit (TB-LAMP; based on the loop-mediated isothermal amplification assay), smear microscopy and Xpert test with the gold standard of mycobacterial culture.

METHODS

Sputum samples were collected from 705 patients with symptoms of pulmonary TB attending a primary health care clinic.

RESULTS

The TB-LAMP assay had significantly higher sensitivity than smear microscopy (72.6% vs. 45.4%, P < 0.001), whereas specificity was slightly lower (99% vs. 96.8%, P = 0.05), but significantly higher than Xpert (92.9%, P = 0.004). There was no significant difference in sensitivity of smear-positive, culture-positive and smear-negative, culture-positive sputum samples using TB-LAMP vs. Xpert (respectively 95.9%/55.9% vs. 97.6%/66.1%; P =0.65, P = 0.27). The positive predictive value of TB-LAMP was significantly higher than that of Xpert (87.5% vs. 77.0%; P = 0.02), but similar to that of smear microscopy (94.2%; P = 0.18). The negative predictive value was respectively 91.9%, 92.5% (P = 0.73) and 83.1% (P = 0.0001).

CONCLUSION

Given its ease of operability, the TB-LAMP assay could be implemented as a point-of-care test in primary health care settings, and contribute to reducing treatment waiting times and TB prevalence.

Nurse-managed care for health care workers in southern Africa

In Swaziland, the health care system is experiencing severe scarcity of health care workers (HCWs) due to difficult working conditions, migration and the human immunodeficiency virus (HIV) pandemic. Nurses and other HCWs in Swaziland are personally as affected by communicable diseases as the general population. High levels of HIV and TB co-infection bring added complexity to care. The loss of skilled staff in key positions has had a particularly negative impact on the quality of care and service delivery. The Swaziland Nurses Association (SNA) has established a Centre for Comprehensive Wellness for HCWs in the public and private sector and their immediate families to support the health workforce.

Syphilis in Swaziland: a serological survey

Sera from 536 adults and children in Swaziland were examined for their reactivity in the rapid plasma reagin (RPR) and Treponema pallidum haemagglutination (TPHA) tests. None of 130 sera from children was reactive in either test; 8.6% of sera from 185 healthy adults were reactive in the RPR test and 33% in the TPHA test; 24.5% of 220 sera from patients with genital ulcers were RPR-positive and 45.9% TPHA-positive. The RPR positivity rates were not related to age, but the percentage of RPR-negative, TPHA-positive sera increased with age in both the healthy adults and the patients with genital ulcers. Thus venereal syphilis appears to be responsible for these high positivity rates. Estimates of the yearly incidence of syphilis are identical for both groups--approximately 1.4%, an unusually high figure.

Epidemiology and aetiology of urethritis in Swaziland

The annual incidence of urethritis can be estimated to be at lest 3750 per 100,000 population in Swaziland. In a study of 109 males with symptomatic urethritis 80% had gonorrhoea, 6% non-gonococcal urethritis (ngu) and 14% were classified as having no 'objective' urethritis (less than 5 polymorphonuclear leucocytes per highpower field in the urethral smear). The relative frequency of gonorrhoea was 80 to 95% and of non-gonococcal urethritis 5 to 20 according to which criteria are used for patient selection and/or diagnosis of ngu. Chlamydia trachomatis was cultured in 3.4% of the cases with urethritis, comprising one positive culture in 70 patients with gonorrhoea, one in 5 with ngu, and one in 12 with no 'objective' urethritis. Seventy-one percent of patients, with a comparable percentage in each diagnostic group, had chlamydial antibodies when tested by the micro immunofluorescence test to pooled chlamydial antigens. Interpretation of the chlamydial serologic results indicates that lymphogranuloma venereum is probably endemic in the country, and that oculogenital chlamydial infections are not a problem; this corresponds with the low isolation rate of Chlamydia trachomatis in the urethritis cases. The study shows that the epidemiology and causes of urethritis are clearly of a different pattern to that seen in industrialised countries. This type of study is a sound basis for a simplified but effective urethritis control programme which can be implemented in the para-urban and rural health centres in developing countries.