Anomalous conductivity tensor in the Dirac semimetal Na_3Bi

Na3Bi is a Dirac semimetal with protected nodes that may be sensitive to the breaking of time-reversal invariance in a magnetic field B. We report experiments which reveal that both the conductivity and resistivity tensors exhibit robust anomalies in B. The resistivity $\rho_{xx}$ is B-linear up to 35 T, while the Hall angle exhibits an unusual profile approaching a step-function. The conductivities $\sigma_{xx}$ and $\sigma_{xy}$ share identical power-law dependences at large B. We propose that these significant deviations from conventional transport result from an unusual sensitivity of the transport lifetime to B. Comparison with Cd3As2 is made.Comment: 8 pages, 5 figure

Caring for transgender people: looking beyond the hype.

This special issue of Sexual Health presents a collection of articles that addresses issues facing transgender individuals that are particularly challenging. Issues covered range from sexual health education in schools, the need for accurate epidemiological measurements, the perils of inaccurate diagnostic labels of transgender children, legal issues, the disproportionately high prevalence of HIV and sexually transmissible infections (STIs), and the role of primary care. We need to think critically, constructively and compassionately about transgender people. Particularly, we must look beyond the hype and objectively consider the evidence, without forgetting the people who are trying to cope with feelings that may be causing them great distress

Gonorrhoea: tackling the global epidemic in the era of rising antimicrobial resistance.

This Special Issue of Sexual Health aims to collate the latest evidence base focussed on understanding the current epidemic and transmission of gonorrhoea, choice of treatment, molecular epidemiology application, concerns about antimicrobial resistance and alternative prevention and control for gonorrhoea

Exploring anal self-examination as a means of screening for anal cancer in HIV positive men who have sex with men: a qualitative study

Background: Anal cancer is relatively common in HIV-positive men who have sex with men(MSM). However there are no clear guidelines on how to effectively screen for anal cancer. As earlier diagnosis of anal cancer is associated with increased survival, innovative ways such as utilizing anal self-examination to identify anal cancer should be explored. Method: Semi-structured interviews were conducted with 20 HIV-positive MSM from a range of ages (35 to 78 years). This study explored acceptability and barriers to implementing ASE as a method of anal cancer screening. Framework analysis was used to identify themes. Results: Seventeen out of 20 men had conducted an ASE before - six (35%) were for medical reasons, six (35%) for sexual reasons, three (18%) for both medical and sexual reasons, and two (12%) for cleaning purposes. Only 5 men were currently confident in detecting an abnormality. Whilst men were generally comfortable with the idea of utilizing ASE as a means for detecting anal cancer, potential barriers identified operated at three levels: attitudinal (discomfort with any anal examinations, anxiety about finding an abnormality, preference for health professional examination), knowledge (lack of awareness of anal cancer risk and ignorance of anal cancer symptoms) and practical (inadequate physical flexibility, importance of hygiene). Conclusion: ASE may be an acceptable means for anal cancer detection in HIV-positive MSM but training in detecting abnormalities is needed. The preference for health professional examination and inadequate physical flexibility may preclude its use for some men. Future trials to confirm its wider acceptability will be needed before undertaking an effectiveness trial for detecting anal cancer

Sustaining sexual and reproductive health through COVID-19 pandemic restrictions: qualitative interviews with Australian clinicians

Background. The sexual and reproductive health care of people with HIV and those at risk of HIV has largely been delivered face-to-face in Australia. These services adapted to the coronavirus disease 2019 (COVID-19) pandemic with a commitment to continued care despite major impacts on existing models and processes. Limited attention has been paid to understanding the perspectives of the sexual and reproductive health care workforce in the research on COVID-19 adaptations. Methods. Semi-structured interviews were conducted between June and September 2021 with 15 key informants representing a diverse range of service settings and professional roles in the Australian sexual and reproductive health sector. Inductive themes were generated through a process of reflexive thematic analysis, informed by our deductive interest in clinical adaptations. Results. The major adaptations were: triage (rapidly adapting service models to protect the most essential forms of care); teamwork (working together to overcome ongoing threats to service quality and staff wellbeing), and the intwined themes of telehealth and trust (remaining connected to marginalised communities through remote care). Despite impacts on care models and client relationships, there were sustained benefits from the scaleup of remote care, and attention to service safety, teamwork and communication. Conclusions. Attending to the experiences of those who worked at the frontline of the COVID-19 response provides essential insights to inform sustained, meaningful system reform over time. The coming years will provide important evidence of longer-term impacts of COVID-19 interruptions on both the users and providers of sexual and reproductive health services

Crowdsourcing to Improve HIV and Sexual Health Outcomes: a Scoping Review.

PURPOSE OF REVIEW: This review synthesizes evidence on the use of crowdsourcing to improve HIV/sexual health outcomes. RECENT FINDINGS: We identified 15 studies, including four completed randomized controlled trials (RCTs), one planned RCT, nine completed observational studies, and one planned observational study. Three of the four RCTs suggested that crowdsourcing is an effective, low-cost approach for improving HIV testing and condom use among key populations. Results from the observational studies revealed diverse applications of crowdsourcing to inform policy, research, and intervention development related to HIV/sexual health services. Crowdsourcing can be an effective tool for informing the design and implementation of HIV/sexual health interventions, spurring innovation in sexual health research, and increasing community engagement in sexual health campaigns. More research is needed to examine the feasibility, acceptability, and effectiveness of crowdsourcing interventions, particularly in low- and middle-income countries

Preferences for HIV testing services among young people in Nigeria.

BACKGROUND: Despite high HIV incidence rates among young people in Nigeria, less than 24% of this population have ever tested for HIV. These low HIV testing rates suggest that current testing services may not align with their testing preferences. To address this gap, the objective of this study was to assess preferences for HIV testing options among young people in Nigeria. METHODS: We conducted a cross-sectional study using survey to assess preferences for HIV testing options among 113 youth aged 14-24 years residing in Nigeria. The survey included a series of hypothetical HIV testing options, comprised of six characteristics centered around HIV testing service (i.e. location of testing, test administrator, mode of pre-test, mode of post-test counseling, type of HIV test, and cost of HIV test). For each characteristic, participants were asked to select one of the options that they prefer or indicate none of the above. A descriptive analysis of the preferences made by participants was conducted, summarizing proportions of participants who selected different options for HIV testing. RESULTS: The mean age of study participants was 19.5 years old (SD = 2.7). Most youth (73, 64.6%) had at least a secondary school degree. There was pronounced heterogeneity in HIV testing preferences among young people. Although most youth preferred free HIV testing, 14 (16.7%) reported preferring paying a small amount compared to free testing. More youth preferred blood-based HIV self-testing 39(48.8%) compared to facility-based HIV testing and oral HIV self-testing. CONCLUSIONS: Our finding suggest that young people have a range of HIV testing preferences in Nigeria. This suggests that a "one-size-fits-all" approach to delivering services to youth may be challenging in this context. HIV testing services can be optimized to reach young people if a variety options are provided to meet their unique preferences

Heterogeneity in individual preferences for HIV testing: A systematic literature review of discrete choice experiments.

BACKGROUND: Understanding variations in HIV testing preferences can help inform optimal combinations of testing services to maximize coverage. We conducted a systematic review of Discrete Choice Experiments (DCEs) eliciting HIV testing preference. METHODS: We searched the published literature for papers that conducted DCEs to assess user preferences for HIV testing. FINDINGS: We identified 237 publications; 14 studies conducted in 10 countries met inclusion criteria. Overall, test cost was one of the strongest drivers of preference, with participants preferring free or very low-cost testing. Confidentiality was a salient concern, particularly among key populations and persons who never tested. Participants in resource-limited settings preferred short travel distance and integration of HIV testing with other services. There was substantial heterogeneity across participant characteristics. For example, while women preferred home testing, high-risk groups (e.g. male porters, female bar workers) and men who had not tested in the last year preferred traveling a short distance for testing. HIV self-testing (HIVST) had high acceptability, particularly among those who had never HIV tested, although most users preferred blood-based sample collection over oral swabs. Participants highly valued post-test counselling availability after HIVST. INTERPRETATION: Overall, participants value low-cost, confidential testing with short travel distance. HIVST is a promising strategy to increase testing coverage but post-test counseling and support should be made available. Educational campaigns to increase familiarity and build confidence in results of oral testing can improve the success of HIVST. DCEs conducted within clinic settings likely have limited generalizability to those not seeking care, particularly for key populations

Bulk crystal growth and electronic characterization of the 3D Dirac Semimetal Na3Bi

High quality hexagon plate-like Na3Bi crystals with large (001) plane surfaces were grown from a molten Na flux. The freshly cleaved crystals were analyzed by low temperature scanning tunneling microscopy (STM) and angle-resolved photoemission spectroscopy (ARPES), allowing for the characterization of the three-dimensional (3D) Dirac semimetal (TDS) behavior and the observation of the topological surface states. Landau levels (LL) were observed, and the energy-momentum relations exhibited a linear dispersion relationship, characteristic of the 3D TDS nature of Na3Bi. In transport measurements on Na3Bi crystals the linear magnetoresistance and Shubnikov-de Haas (SdH) quantum oscillations are observed for the first time.Comment: To be published in a special issue of APL Material