Project Apollo - The effect of the selection of the cabin pressure on the environmental control system

Effect of cabin pressure on environmental control syste

Integrated control system for a gas turbine engine

A control system for a turbofan engine receives signals from a number of engine sensors and from the engine operator, and generates control signals. One control signal regulates the fan exhaust nozzle area in order to control inlet throat Mach number to maintain a low level of engine noise. Additional control signals regulate fuel flow to control engine thrust and fan pitch to control fan speed. A number of schedules are utilized to maintain a predetermined relationship between the controlled parameters and a number of fixed and calculated limits can override the control signals to prevent unsatisfactory engine performance

Changes in STI and HIV testing and testing need among men who have sex with men during the UK's COVID-19 pandemic response.

OBJECTIVES: We examined the impact of COVID-19-related restrictions on sexual behaviours, STI and HIV testing and testing need among men who have sex with men (MSM) in the UK. METHODS: We used social media and dating applications to recruit to three cross-sectional surveys (S1-S3) during the UK's pandemic response (S1: 23 June-14 July 2020; S2: 23 November-12 December 2020; S3: 23 March-14 April 2021). Surveys included lookback periods of around 3-4 months (P1-P3, respectively). Eligible participants were UK resident men (cisgender/transgender) and gender-diverse people assigned male at birth (low numbers of trans and gender-diverse participants meant restricting these analyses to cisgender men), aged ≥16 years who reported sex with men (cisgender/transgender) in the last year (S1: N=1950; S2: N=1463; S3: N=1487). Outcomes were: recent STI/HIV testing and unmet testing need (new male and/or multiple condomless anal sex partners without a recent STI/HIV test). Crude and adjusted associations with each outcome were assessed using logistic regression. RESULTS: Participants' sociodemographic characteristics were similar across surveys. The proportion reporting a recent STI and/or HIV test increased between P1 and P2 (25.0% to 37.2% (p<0.001) and 29.7% to 39.4% (p<0.001), respectively), then stabilised in P3 (40.5% reporting HIV testing). Unmet STI testing need increased across P1 and P2 (26.0% to 32.4%; p<0.001), but trends differed between groups, for example, unmet STI testing need was higher in bisexually-identifying (vs gay-identifying) MSM across periods (adjusted OR (aOR): P1=1.64; P2=1.42), but declined in HIV-positive (vs HIV-negative/unknown) MSM (aOR: P1=2.06; P2=0.68). Unmet HIV testing need increased across P1 and P2 (22.9% to 31.0%; p<0.001) and declined in P3 (25.1%; p=0.001). During P3, MSM reporting a low life-satisfaction level (vs medium-very high) had greater unmet need (aOR: 1.44), while from P2 onwards HIV pre-exposure prophylaxis users (vs non-users) had lower unmet need (aOR: P2=0.32; P3=0.50). CONCLUSION: Considerable unmet STI/HIV testing need occurred among MSM during COVID-19-related restrictions, especially in bisexually-identifying men and those reporting low life satisfaction. Improving access to STI/HIV testing in MSM is essential to prevent inequalities being exacerbated

Sexual behaviour, STI and HIV testing and testing need among gay, bisexual and other men who have sex with men recruited for online surveys pre/post-COVID-19 restrictions in the UK.

OBJECTIVES: We examined sexual behaviour, sexually transmitted infection (STI) and HIV testing and testing need, and identified associated factors, among gay, bisexual and other men who have sex with men (GBMSM) in the UK after COVID-19 restrictions ended, and compared these with 'pre-pandemic' estimates. METHODS: We analysed survey data from GBMSM (N=1039) recruited via social media and Grindr in November-December 2021. We then compared Grindr-recruited 2021 participants (N=437) with those from an equivalent survey fielded in March-May 2017 (N=1902). Questions on sexual behaviour and service use had lookback periods of 3-4 months in both surveys. Unmet testing need was defined as reporting any new male and/or multiple condomless anal sex (CAS) partners without recent STI/HIV testing. Participants were UK residents, GBMSM, aged ≥16 years who reported sex with men in the last year. Multivariable logistic regression identified associated sociodemographic and health-related factors with unmet STI/HIV testing need in 2021, and then for 2017/2021 comparative analyses, adjusting for demographic differences. RESULTS: In 2021, unmet STI and HIV testing need were greater among older GBMSM (aged ≥45 years vs 16-29 years; adjusted OR (aOR): 1.45 and aOR: 1.77, respectively), and lower for pre-exposure prophylaxis (PrEP) users (vs non-PrEP users; aOR: 0.32 and aOR: 0.23, respectively). Less unmet STI testing need was observed among HIV-positive participants (vs HIV-negative/unknown; aOR: 0.63), and trans and non-binary participants (vs cisgender male; aOR: 0.34). Between 2017 (reference) and 2021, reported sexual risk behaviours increased: ≥1 recent new male sex partner (72.1%-81.1%, aOR: 1.71) and ≥2 recent CAS partners (30.2%-48.5%, aOR: 2.22). Reporting recent STI testing was greater in 2021 (37.5%-42.6%, aOR: 1.34) but not recent HIV testing, and there was no significant change over time in unmet STI (39.2% vs 43.7%) and HIV (32.9% vs 39.0%) testing need. DISCUSSION: Comparable community surveys suggest that UK resident GBMSM may have engaged in more sexual risk behaviours in late 2021 than pre-pandemic. While there was no evidence of reduced STI/HIV service access during this time, there remained considerable unmet STI/HIV testing need

Difficulty accessing condoms because of the COVID-19 pandemic reported by gay, bisexual and other men who have sex with men in the UK: findings from a large, cross-sectional, online survey.

BACKGROUND: COVID-19 restrictions severely reduced face-to-face sexual health services, an important access point for condoms. We examine whether gay, bisexual and other men who have sex with men (GBMSM) in the UK had difficulty accessing condoms during the first year of the pandemic, and if so, which groups were most affected. METHODS: Questions about difficulty accessing condoms were asked as part of a short, online cross-sectional survey of GBMSM undertaken November/December 2021, recruited via social media and Grindr. Eligible participants were UK-resident GBMSM (cis/trans/gender-diverse person assigned male at birth [AMAB]), aged ≥16 years who were sexually active (reported sex with men in the last year). Multivariable logistic regression was used to examine if and how reporting this outcome varied by key sociodemographic, health and behavioural factors independent of the potential confounding effect of numbers of new male sex partners. RESULTS: Of all participants (N = 1039), 7.4% (n = 77) reported difficulty accessing condoms due to the pandemic. This was higher among younger GBMSM (aged 16-29 years vs. ≥45; 12.8% vs. 4.9%; aOR: 2.78); trans/gender-diverse AMAB participants (vs. cis gender males; 24.4% vs. 6.6%; aOR = 4.86); bisexually-identifying participants (vs. gay-identifying; 11.1% vs. 6.5%; aOR = 1.78); and those without degree level education (vs. having a degree; 9.8% vs. 5.6%; aOR = 2.01). CONCLUSIONS: A minority of sexually active GBMSM reported difficulty accessing condoms because of the pandemic, however, this was more common amongst those who already experience a disproportionate burden of poor sexual health. Interventions are needed to address these inequalities in accessing this important primary STI/HIV prevention measure

Illuminating subduction zone rheological properties in the wake of a giant earthquake

Deformation associated with plate convergence at subduction zones is accommodated by a complex system involving fault slip and viscoelastic flow. These processes have proven difficult to disentangle. The 2010 Mw 8.8 Maule earthquake occurred close to the Chilean coast within a dense network of continuously recording Global Positioning System stations, which provide a comprehensive history of surface strain. We use these data to assemble a detailed picture of a structurally controlled megathrust fault frictional patchwork and the three-dimensional rheological and time-dependent viscosity structure of the lower crust and upper mantle, all of which control the relative importance of afterslip and viscoelastic relaxation during postseismic deformation. These results enhance our understanding of subduction dynamics including the interplay of localized and distributed deformation during the subduction zone earthquake cycle

Search for the Neutron Decay n→\rightarrow X+γ\gamma where X is a dark matter particle

In a recent paper submitted to Physical Review Letters, Fornal and Grinstein have suggested that the discrepancy between two different methods of neutron lifetime measurements, the beam and bottle methods can be explained by a previously unobserved dark matter decay mode, n$\rightarrow$ X+$\gamma$ where X is a dark matter particle. We have performed a search for this decay mode over the allowed range of energies of the monoenergetic gamma ray for X to be a dark matter particle. We exclude the possibility of a sufficiently strong branch to explain the lifetime discrepancy with greater than 4 sigma confidence.Comment: 6 pages 3 figure