Lunar Lander Structural Design Studies at NASA Langley

The National Aeronautics and Space Administration is currently developing mission architectures, vehicle concepts and flight hardware to support the planned human return to the Moon. During Phase II of the 2006 Lunar Lander Preparatory Study, a team from the Langley Research Center was tasked with developing and refining two proposed Lander concepts. The Descent-Assisted, Split Habitat Lander concept uses a disposable braking stage to perform the lunar orbit insertion maneuver and most of the descent from lunar orbit to the surface. The second concept, the Cargo Star Horizontal Lander, carries ascent loads along its longitudinal axis, and is then rotated in flight so that its main engines (mounted perpendicular to the vehicle longitudinal axis) are correctly oriented for lunar orbit insertion and a horizontal landing. Both Landers have separate crew transport volumes and habitats for surface operations, and allow placement of large cargo elements very close to the lunar surface. As part of this study, lightweight, efficient structural configurations for these spacecraft were proposed and evaluated. Vehicle structural configurations were first developed, and preliminary structural sizing was then performed using finite element-based methods. Results of selected structural design and trade studies performed during this activity are presented and discussed

Pre-exposure prophylaxis initiation and adherence among Black men who have sex with men (MSM) in three US cities: results from the HPTN 073 study

Abstract : Introduction: Randomized clinical trials have demonstrated the efficacy of antiretroviral pre-exposure prophylaxis (PrEP) in preventing HIV acquisition among men who have sex with men (MSM). However, limited research has examined initiation and adherence to PrEP among Black MSM (BMSM) in the United States (US) who are disproportionately represented among newly HIV infected and late to care individuals. This research reports on the HIV Prevention Trials Network 073 (HPTN 073) study aimed to examine PrEP initiation, utilization and adherence among Black MSM utilizing the theoretically principled, cul- turally informed and client-centered care coordination (C4) model. Methods: The HPTN 073 study enrolled and followed 226 HIV-uninfected Black MSM in three US cities (Los Angeles, CA; Washington DC; and Chapel Hill, NC) from February 2013 through September 2015. Study participants were offered once daily oral emtricitabine/tenofovir (FTC/TDF) PrEP combined with C4 and followed up for 52 weeks. Participants received HIV testing, risk reduction education and clinical monitoring. Results: Of the 226 men enrolled, 178 participants initiated PrEP (79%), and of these 64% demonstrated PrEP utilization at week 26 (mid-point of the study) based on pharmacokinetic testing. Condomless anal sex with an HIV-infected or unknown status casual male partner was statistically significantly associated with a greater likelihood of PrEP initiation (adjusted odds ratio (OR) 4.4, 95% confidence interval (CI) 1.7, 11.7). Greater age (≥25 vs. <25, OR 2.95, 95% CI 1.37 –6.37), perception of having enough money (OR 3.6, 95% CI 1.7 to 7.7) and knowledge of male partner taking PrEP before sex (OR 2.22, 95% CI 1.03 to 4.79) were statistically significantly associated with increased likelihood of PrEP adherence at week 26. Annualized HIV incidence was 2.9 (95% CI 1.2 to 7.9) among those who initiated PrEP, compared to 7.7 (95% CI 2.5 to 24.1) among those who did not initiate PrEP (p = 0.18). Conclusions: Results suggest a high level of PrEP initiation among at-risk Black MSM, a group historically characterized as hard to reach. The data support the importance of addressing contextual factors that affect PrEP initiation and adherence, and of additional research on the ultimate benefit of PrEP in HIV prevention among Black MSM

Retention Strategies and Factors Associated with Missed Visits Among Low Income Women at Increased Risk of HIV Acquisition in the US (HPTN 064)

Women at high-risk for HIV acquisition often face challenges that hinder their retention in HIV prevention trials. These same challenges may contribute to missed clinical care visits among HIV-infected women. This article, informed by the Gelberg-Andersen Behavioral Model for Vulnerable Populations, identifies factors associated with missed study visits and describes the multifaceted retention strategies used by study sites. HPTN 064 was a multisite, longitudinal HIV seroincidence study in 10 US communities. Eligible women were aged 18–44 years, resided in a census tract/zipcode with high poverty and HIV prevalence, and self-reported ≥1 personal or sex partner behavior related to HIV acquisition. Multivariate analyses of predisposing (e.g., substance use) and enabling (e.g., unmet health care needs) characteristics, and study attributes (i.e., recruitment venue, time of enrollment) identified factors associated with missed study visits. Retention strategies included: community engagement; interpersonal relationship building; reduction of external barriers; staff capacity building; and external tracing. Visit completion was 93% and 94% at 6 and 12 months. Unstable housing and later date of enrollment were associated with increased likelihood of missed study visits. Black race, recruitment from an outdoor venue, and financial responsibility for children were associated with greater likelihood of attendance. Multifaceted retention strategies may reduce missed study visits. Knowledge of factors associated with missed visits may help to focus efforts

Sexual Behavior and Network Characteristics and Their Association with Bacterial Sexually Transmitted Infections among Black Men Who Have Sex with Men in the United States

Black men who have sex with men (MSM) have a high prevalence of bacterial sexually transmitted infections (STIs), and individual risk behavior does not fully explain the higher prevalence when compared with other MSM. Using the social-ecological framework, we evaluated individual, social and sexual network, and structural factors and their association with prevalent STIs among Black MSM

The Overseeing Mother: Revisiting the Frontal-Pose Lady in the Wu Family Shrines in Second Century China

Located in present-day Jiaxiang in Shandong province, the Wu family shrines built during the second century in the Eastern Han dynasty (25–220) were among the best-known works in Chinese art history. Although for centuries scholars have exhaustively studied the pictorial programs, the frontal-pose female image situated on the second floor of the central pavilion carved at the rear wall of the shrines has remained a question. Beginning with the woman’s eyes, this article demonstrates that the image is more than a generic portrait (“hard motif ”), but rather represents “feminine overseeing from above” (“soft motif ”). This synthetic motif combines three different earlier motifs – the frontal-pose hostess enjoying entertainment, the elevated spectator, and the Queen Mother of the West. By creatively fusing the three motifs into one unity, the Jiaxiang artists lent to the frontal-pose lady a unique power: she not only dominated the center of the composition, but also, like a divine being, commanded a unified view of the surroundings on the lofty building, hence echoing the political reality of the empress mother’s “overseeing the court” in the second century during Eastern Han dynasty

Sexual Behavior and Network Characteristics and Their Association with Bacterial Sexually Transmitted Infections among Black Men Who Have Sex with Men in the United States.

BACKGROUND: Black men who have sex with men (MSM) have a high prevalence of bacterial sexually transmitted infections (STIs), and individual risk behavior does not fully explain the higher prevalence when compared with other MSM. Using the social-ecological framework, we evaluated individual, social and sexual network, and structural factors and their association with prevalent STIs among Black MSM. METHODS: The HIV Prevention Trials Network 061 was a multi-site cohort study designed to determine the feasibility and acceptability of a multi-component intervention for Black MSM in six US cities. Baseline assessments included demographics, risk behavior, and social and sexual network questions collected information about the size, nature and connectedness of their sexual network. Logistic regression was used to estimate the odds of having any prevalent sexually transmitted infection (gonorrhea, chlamydia, or syphilis). RESULTS: A total of 1,553 Black MSM were enrolled in this study. In multivariate analysis, older age (aOR = 0.57; 95% CI 0.49-0.66, p\u3c0.001) was associated with a lower odds of having a prevalent STI. Compared with reporting one male sexual partner, having 2-3 partners (aOR = 1.74; 95% CI 1.08-2.81, p\u3c0.024) or more than 4 partners (aOR = 2.29; 95% CI 1.43-3.66, p\u3c0.001) was associated with prevalent STIs. Having both Black and non-Black sexual partners (aOR = 0.67; 95% CI 0.45-0.99, p = 0.042) was the only sexual network factor associated with prevalent STIs. CONCLUSIONS: Age and the number and racial composition of sexual partners were associated with prevalent STIs among Black MSM, while other sexual network factors were not. Further studies are needed to evaluate the effects of the individual, network, and structural factors on prevalent STIs among Black MSM to inform combination interventions to reduce STIs among these men

Acceptability of a mobile smartphone application intervention to improve access to HIV prevention and care services for black men who have sex with men in the district of columbia.

Eliminating racial HIV disparities among men who have sex with men (MSM) will require a greater uptake of HIV prevention and care interventions among Black MSM (BMSM), yet such strategies generally require meaningful engagement in a health care system that often does not meet the unique needs of BMSM. This study assessed the acceptability of, and correlates of having favorable perceptions of, a mobile smartphone application (app) intervention for BMSM that aims to remove structural barriers and improve access to culturally relevant HIV prevention and care services. An Internet-based sample of 93 BMSM completed an online survey on their perceptions of the app using 14 items measured on a 100-point visual analogue scale that were validated in exploratory factor analysis (alpha=0.95). Among the sample, perceptions of two sample app modules were generally favorable and most BMSM agreed that they would use the modules (81.2% and 87.1%). Correlates of having favorable perceptions included trusting medical advice from social networks, lacking private health insurance, and not having accessed a primary care physician in the last year. Our findings warrant the further development of this app and point to subgroups of BMSM for which it may have the greatest impact

Receipt of HIV prevention interventions is more common in community-based clinics than in primary care or acute care settings for Black men who have sex with men in the District of Columbia.

Characterization of structural barriers that impede the use of HIV prevention and care services is critical to addressing the HIV epidemic among Black men who have sex with men (BMSM). This study investigated the utilization of HIV prevention services and general care services among a non-clinic-based sample of BMSM who reported at least one structural barrier to engagement in care. We recruited BMSM in the District of Columbia metropolitan area via incentivized peer referral to complete a computer-assisted self-interview on health care experiences. Proportions of participants who had received HIV prevention services and general care services in different settings were compared using Fisher’s exact test and correlates of service receipt were assessed using logistic regression. Among 75 BMSM with at least one barrier to care, 84% were <30 years old, 11% were HIV-positive, and 75% had health insurance. In the last six months, 60% had accessed a community-based clinic, 21% had accessed a primary care setting, and 36% had accessed an acute care setting. Greater proportions of participants who had accessed community-based clinics received HIV prevention services during these visits (90%) compared to those who had accessed primary care (53%) and acute care (44%) settings (p=0.005). Opportunities for BMSM to receive HIV prevention interventions differed by care setting. Having access to health care does not necessarily facilitate the uptake of HIV prevention interventions for BMSM. Further investigation of the structurally rooted reasons why BMSM are often unable to access HIV prevention services that would reduce racial disparities in HIV incidence is warranted

The magic of the market place: Sociality in a neglected public space

This study explores the potentiality of markets as public space where multiple forms of sociality are enacted. Research was conducted in eight UK markets. The research revealed that markets represented a significant public and social space for different groups in the locality as a site for vibrant social encounters, for social inclusion and the care of others, for `rubbing along' and for mediating differences. The article concludes by arguing that the social encounters and connections found in markets contradict pessimistic accounts of the decline of social association, offering a contrast to the shopping mall and providing the possibility for the inclusion of marginalised groups and for the co-mingling of differences where these are increasingly relegated to more private sphere