Thermal Performance Expectations of the Advanced Stirling Convertor Over a Range of Operating Scenarios

The Advanced Stirling Radioisotope Generator (ASRG) will enable various missions such as small body sample return, atmospheric missions around Venus, as well as long - duration deep space missions. Analysis of the temperature distributions are performed on an Advanced Stirling Convertor, and the results are compared with available experimental measurements. This analysis includes applied environmental conditions that are similar to those that will be experienced while the convertor is in operation. The applied conditions represent a potential mission profile including pre-takeoff sterilization, launch, transit, and return. The results focus on the anticipated peak temperatures of the magnets in the linear alternator. These results confirm that the ASC can support future missions to deep space targets, extreme environment landers, as well as more conventional goals

Preferences for HIV testing services among men who have sex with men in the UK: A discrete choice experiment.

BACKGROUND: In the UK, approximately 4,200 men who have sex with men (MSM) are living with HIV but remain undiagnosed. Maximising the number of high-risk people testing for HIV is key to ensuring prompt treatment and preventing onward infection. This study assessed how different HIV test characteristics affect the choice of testing option, including remote testing (HIV self-testing or HIV self-sampling), in the UK, a country with universal access to healthcare. METHODS AND FINDINGS: Between 3 April and 11 May 2017, a cross-sectional online-questionnaire-based discrete choice experiment (DCE) was conducted in which respondents who expressed an interest in online material used by MSM were asked to imagine that they were at risk of HIV infection and to choose between different hypothetical HIV testing options, including the option not to test. A variety of different testing options with different defining characteristics were described so that the independent preference for each characteristic could be valued. The characteristics included where each test is taken, the sampling method, how the test is obtained, whether infections other than HIV are tested for, test accuracy, the cost of the test, the infection window period, and how long it takes to receive the test result. Participants were recruited and completed the instrument online, in order to include those not currently engaged with healthcare services. The main analysis was conducted using a latent class model (LCM), with results displayed as odds ratios (ORs) and probabilities. The ORs indicate the strength of preference for one characteristic relative to another (base) characteristic. In total, 620 respondents answered the DCE questions. Most respondents reported that they were white (93%) and were either gay or bisexual (99%). The LCM showed that there were 2 classes within the respondent sample that appeared to have different preferences for the testing options. The first group, which was likely to contain 86% of respondents, had a strong preference for face-to-face tests by healthcare professionals (HCPs) compared to remote testing (OR 6.4; 95% CI 5.6, 7.4) and viewed not testing as less preferable than remote testing (OR 0.10; 95% CI 0.09, 0.11). In the second group, which was likely to include 14% of participants, not testing was viewed as less desirable than remote testing (OR 0.56; 95% CI 0.53, 0.59) as were tests by HCPs compared to remote testing (OR 0.23; 95% CI 0.15, 0.36). In both classes, free remote tests instead of each test costing £30 was the test characteristic with the largest impact on the choice of testing option. Participants in the second group were more likely to have never previously tested and to be non-white than participants in the first group. The main study limitations were that the sample was recruited solely via social media, the study advert was viewed only by people expressing an interest in online material used by MSM, and the choices in the experiment were hypothetical rather than observed in the real world. CONCLUSIONS: Our results suggest that preferences in the context we examined are broadly dichotomous. One group, containing the majority of MSM, appears comfortable testing for HIV but prefers face-to-face testing by HCPs rather than remote testing. The other group is much smaller, but contains MSM who are more likely to be at high infection risk. For these people, the availability of remote testing has the potential to significantly increase net testing rates, particularly if provided for free

Editorial honoring the 2018 reviewers for JGR Space Physics

The Editors of the Journal of Geophysical Research Space Physics would like to honor and thank the 2018 manuscript reviewers for the journal. This is a large‐scale, community‐wide effort for which 1,358 scientists submitted 3,027 reviews in 2018. We understand that this is a volunteer task and we greatly appreciate your time and effort to fulfill this service role back to the research community

The Raploch: A history, people's perceptions and the likely future of a problem housing estate

This article explores the experience of belonging and identity, and the social distance and separateness which has long characterised aspects of Stirling’s Raploch housing estate. Detailed historical archive work uncovered the limited social planning and architectural ambitions set for this housing estate, when compared to the earlier Riverside development. The consequences of such decision making and subsequent poor management of the estate is then articulated through a series of qualitative interviews which explore attitudes to the construction and sustaining of neighbourhood and community identities. Achieving a physical solution to Raploch's social problems has eluded a series of recent regeneration initiatives and this paper suggests that the core problem is not primarily architectural but rather one of class related discrimination and stigma which has been core to Raploch's identity since the 16th Century

Evaluating HIV treatment as prevention in the European context

Executive summary The goal of this project is to gather evidence regarding the population-level, and to some extent, individual-level effects of the use of antiretroviral treatment (ART) to prevent HIV infection, and to relate this to current HIV treatment guidelines. To inform the project, formal literature reviews were performed for the three main areas of interest: the effect of antiretroviral therapy in adults on preventing sexual transmission of HIV, prevention of mother-to-child transmission (pMTCT) and post exposure prophylaxis (PEP). The strongest evidence with regard to the effect of treatment of HIV positive individuals to prevent onwards sexual transmission comes from the recent randomised controlled trial (RCT), HPTN052. This study demonstrated that early versus delayed ART led to a 96% relative reduction in onwards linked transmission. Several observational studies of HIV sero-discordant heterosexual couples have also reported that transmission is rare in patients on ART, particularly in those with low HIV-RNA concentrations. However, the findings of HPTN052 and these observational studies are mainly applicable to vaginal heterosexual sex. No direct empirical evidence regarding the relationship between ART use and the risk of HIV transmission through anal intercourse is currently available. Whilst the major HIV treatment guidelines do not explicitly recommend prescribing antiretroviral treatment to prevent onwards transmission, they do not rule out individuals starting ART at a high CD4 count on a case-by-case basis. However, one must also consider the impact of earlier treatment on the HIV positive individual with regard to side effects, and development of drug resistance. Early studies showed that pMTCT regimens containing a single antiretroviral agent (short course zidovudine or single dose nevirapine) or two antiretroviral agents (zidovudine and lamivudine with or without single dose nevirapine) led to clinically important reductions in MTCT rates. However, the most substantial reductions in MTCT rates occurred when combination antiretroviral regimens (more than three antiretroviral drugs) were introduced. These regimens involve the receipt of ART before the third trimester of pregnancy, intrapartum treatment, maternal post-partum treatment and some form of neonatal treatment. There is some evidence from RCTs and extensive evidence from observational studies of the efficacy of these combination regimens, with very low rates of transmission of around 0% to 6%, in settings with no or very little breastfeeding, and 1%-9% when breastfeeding occurs. Furthermore, in settings where avoidance of breastfeeding is not possible, there are a number of studies demonstrating that receipt of maternal and/or neonatal ART during the six months after birth can reduce the risk of perinatal transmissions. All treatment guidelines recommend that HIV-positive pregnant women should receive ART to prevent MTCT, although the exact timing of when ART should begin is not always explicit. Furthermore, where mentioned, use of neonatal ART is also recommended, regardless of whether infants are breastfed. Much of the data supporting the use of PEP are based on animal models, which suggest that PEP is most efficacious if commenced as soon as possible after exposure. When considering occupational exposure to HIV, human studies are limited, as no RCTs exist for ethical reasons. Evidence for efficacy is based on one case control study which demonstrated an 81% reduction in transmission of HIV through the use of zidovudine. Other studies have demonstrated that PEP following occupational exposure is not always effective and there are cases of PEP failure. Similarly, there are also no RCTs assessing the efficacy of PEP for prevention of HIV transmission after sexual exposure, and limited evidence from observational data. Most treatment guidelines agree that PEP is not always effective and PEP policies need to emphasise the importance of risk prevention in the first place in all settings where there is a risk of HIV transmission. Side effects are not uncommon when using PEP, so it is important to consider carefully whether an individual should receive PEP and some studies have suggested that increase in availability of PEP may lead to an increase in risky sex behaviour. Antiretroviral treatment has well documented benefits in reducing transmission of HIV and, in particular, has had a major population level impact on HIV acquisition in children from HIV positive mothers. Further research is needed to help us understand how we can best use ART to prevent HIV infections through other transmission routes, and to develop evidence-based policy recommendations, particularly in the European context

NICMOS Imaging of a Damped Lyman-alpha Absorber at z=1.89 toward LBQS 1210+1731 : Constraints on Size and Star Formation Rate

We report results of a high-resolution imaging search (in rest frame H-$\alpha$ and optical continuum) for the galaxy associated with the damped Lyman-$\alpha$ (DLA) absorber at $z=1.892$ toward the $z_{em}=2.543$ quasar LBQS 1210+1731, using HST/NICMOS. After PSF subtraction, a feature is seen in both the broad-band and narrow-band images, at a projected separation of 0.25\arcsec from the quasar. If associated with the DLA, the object would be $\approx 2-3$ $h_{70}^{-1}$ kpc in size with a flux of $9.8 \pm 2.4$ $\mu$Jy in the F160W filter, implying a luminosity at $\lambda_{central}=5500$ {\AA} in the rest frame of $1.5 \times 10^{10}$ $h_{70}^{-2}$ L$_{\odot}$ at $z=1.89$, for $q_{0}=0.5$. However, no significant H-$\alpha$ emission is seen, suggesting a low star formation rate (SFR) (3 $\sigma$ upper limit of 4.0 $h_{70}^{-2}$ M$_{\odot}$ yr$^{-1}$), or very high dust obscuration. Alternatively, the object may be associated with the host galaxy of the quasar. H-band images obtained with the NICMOS camera 2 coronagraph show a much fainter structure $\approx 4-5$ $h_{70}^{-1}$ kpc in size and containing four knots of continuum emission, located 0.7\arcsec away from the quasar. We have probed regions far closer to the quasar sight-line than in most previous studies of high-redshift intervening DLAs. The two objects we report mark the closest detected high-redshift DLA candidates yet to any quasar sight line. If the features in our images are associated with the DLA, they suggest faint, compact, somewhat clumpy objects rather than large, well-formed proto-galactic disks or spheroids.Comment: 52 pages of text, 19 figures, To be published in Astrophysical Journal (accepted Dec. 8, 1999

The Risks of Downplaying Top-Down Control

Is top-down control necessarily scarce, slow, and hence unimportant in visual selection? Here we outline the risks of downplaying top-down control. Contrary to Theeuwes’ review, we suggest that not all sources of attention map onto a unitary attentional priority map. Goals and search habits may influence where and how people deploy attention, respectively. Because goals have modulatory effects on sensory processing, their impact on attention is broad and not always deliberate. In addition, when multiple sources influence attention, top-down control often dominates over less deliberate forms of attention. We agree with Theeuwes that selection history can drive attention independent of explicit goals. Nonetheless, top-down control remains a cornerstone of visual selection