THEMIS observations and riometry: A data comparison with a view to proxy and prediction

A comparison has been made between radio absorption events observed by riometer at selected times of day and bursts of electrons observed in the midnight sector by THEMIS satellites. The correlation is found to be good for absorption in the noon and midnight sectors but poor around dawn and dusk. For noon and midnight the absorption can be estimated from the THEMIS electron flux to better than a factor of 2 in most cases. In the noon sector the absorption follows the THEMIS event by about 30 min on average (though with considerable variation from case to case), but by night the absorption precedes the electron flux by about 8 min on average. Thus, the flux at THEMIS can be predicted from the absorption in the night sector, the accuracy being better than a factor of 3 in most cases. The flux observed also depends on the location of the satellite, reducing with increasing distance down the tail. It is estimated that the source of the tail events observed in this study was at about 6Re, and comparisons are made with the established general pattern of the substorm in auroral absorption

The dynamics of quasi-periodic ripples in the high-latitude F-region

This study extends the investigation of quasi-periodic ripples in the F-region electron content reported by Birch and Hargreaves (2020a) to determine their flow velocity and wavelength, using data from the EISCAT Svalbard radars (the 42m antenna being field-aligned and the 32m scanning in a circular pattern at a fixed angle from the field). The ripples were extracted from the 42m electron content between altitudes 213 and 389 km in the noon and midnight sectors using a bandpass filter which reduces the noise component while removing long-term trends. These ripples were found to have an average periodicity of about 21 min in the noon sector and 27 min at night. Using the 32m line-of-sight velocity data, they were also found to propagate in the noon sector at about 467 m/s in a westerly direction with a wavelength of 581 km, and in the night sector at about 283 m/s in a southerly direction with a wavelength of 454 km. The directions compare favourably with modelled plasma flows from the SuperDARN network of coherent scatter radars

Observations by incoherent scatter radar of related D- and F-region structuring at very high latitude

Properties and associations of F- and D-region ionospheric structures during weak electron precipitation at very high latitude are investigated using the Longyearbyen incoherent scatter radar. The radio absorption deduced from the electron density observations revealed evidence of a persistent low-altitude absorption layer peaking at 80-85 km. Inversion of the electron density profile to give an estimate of the incoming energetic electron spectrum suggests that its source may be the solar wind. Strong similarities are seen between variations in the F and D regions which suggest that the electron flux reaching the D-region is being modulated in energy by the variations of electron density in the F-region

Opportunities for enhanced strategic use of surveys, medical records, and program data for HIV surveillance of key populations: Scoping review

Background: Normative guidelines from the World Health Organization recommend tracking strategic information indicators among key populations. Monitoring progress in the global response to the HIV epidemic uses indicators put forward by the Joint United Nations Programme on HIV/AIDS. These include the 90-90-90 targets that require a realignment of surveillance data, routinely collected program data, and medical record data, which historically have developed separately. Objective: The aim of this study was to describe current challenges for monitoring HIV-related strategic information indicators among key populations ((men who have sex with men [MSM], people in prisons and other closed settings, people who inject drugs, sex workers, and transgender people) and identify future opportunities to enhance the use of surveillance data, programmatic data, and medical record data to describe the HIV epidemic among key populations and measure the coverage of HIV prevention, care, and treatment programs. Methods: To provide a historical perspective, we completed a scoping review of the expansion of HIV surveillance among key populations over the past three decades. To describe current efforts, we conducted a review of the literature to identify published examples of SI indicator estimates among key populations. To describe anticipated challenges and future opportunities to improve measurement of strategic information indicators, particularly from routine program and health data, we consulted participants of the Third Global HIV Surveillance Meeting in Bangkok, where the 2015 World Health Organization strategic information guidelines were launched. Results: There remains suboptimal alignment of surveillance and programmatic data, as well as routinely collected medical records to facilitate the reporting of the 90-90-90 indicators for HIV among key populations. Studies (n=3) with estimates of all three 90-90-90 indicators rely on cross-sectional survey data. Programmatic data and medical record data continue to be insufficiently robust to provide estimates of the 90-90-90 targets for key populations. Conclusions: Current reliance on more active data collection processes, including key population-specific surveys, remains warranted until the quality and validity of passively collected routine program and medical record data for key populations is optimized

Gender differentials in the impact of parental death: Adolescent's sexual behaviour and risk of HIV infection in rural South Africa

Using data from a longitudinal surveillance study from rural South Africa, we investigated the odds of sexual debut, pregnancy and HIV infection of 15- to 19-year-old adolescents by parental survival. Using descriptive statistics and logistic regressions, we examine the relative risk of orphans compared with non-orphans to have ever had sex, being pregnant and being HIV infected, adjusting for age, sex, socio-economic status, education, being employed and residency. Of 8274 adolescents, 42% were orphaned (one or both parents died). Over 80% of adolescents remained in school, but orphans were significantly more likely to lag behind in grade for age. Female adolescent maternal (aOR 1.32, 95% CI 1.071.62), paternal (aOR 1.26, 95% CI 1.061.49) and dual (aOR 1.37, 95% CI 1.051.78) orphans were significantly more likely than non-orphaned females to have ever had sex; among males it was only paternal (aOR 1.27, 95% CI 1.051.53) orphans. Maternal (aOR 1.49, 95% CI 1.032.15) and dual (aOR 1.74, 95% CI 1.112.73) female orphans relative to non-orphaned females were significantly more likely to be HIV infected; male paternal (aOR 3.41, 95% CI 1.378.46) and dual (aOR 3.54, 95% CI 1.0611.86) orphans had over three-fold the odds of being infected. There was strong evidence that death of mother for girls was associated with increased vulnerability to earlier sexual debut and HIV infection, while fathers appeared to play a significant role in both their son's and daughter's lives

Track D Social Science, Human Rights and Political Science

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138414/1/jia218442.pd