The X-ray eclipse of OY Car resolved with XMM-Newton: X-ray emission from the polar regions of the white dwarf

We present the XMM-Newton X-ray eclipse lightcurve of the dwarf nova OY Car. The eclipse ingress and egress are well resolved for the first time in any dwarf nova placing strong constraints on the size and location of the X-ray emitting region. We find good fits to a simple linear eclipse model, giving ingress/egress durations of 30+/-3 sec. Remarkably this is shorter than the ingress/egress duration of the sharp eclipse in the optical as measured by Wood et al. (1989) and ascribed to the white dwarf (43+/-2 sec). We also find that the X-ray eclipse is narrower than the optical eclipse by 14+/-2 sec, which is precisely the difference required to align the second and third contact points of the X-ray and optical eclipses. We discuss these results and conclude that X-ray emission in OY Car most likely arises from the polar regions of the white dwarf. Our data were originally reported by Ramsay et al (2001), but they did not make a quantitative measurement of eclipse parameters. We have also corrected important timing anomalies present in the data available at that time.Comment: 6 pages, 5 figures; accepted for publication in MNRA

NGTS-4b: A sub-Neptune transiting in the desert

We report the discovery of NGTS-4b, a sub-Neptune-sized planet transiting a 13th magnitude K-dwarf in a 1.34 d orbit. NGTS-4b has a mass M = 20.6 ± 3.0 M⊕ and radius R = 3.18 ± 0.26 R⊕, which places it well within the so-called ‘Neptunian Desert’. The mean density of the planet (3.45 ± 0.95 g cm−3) is consistent with a composition of 100  per cent H2O or a rocky core with a volatile envelope. NGTS-4b is likely to suffer significant mass loss due to relatively strong EUV/X-ray irradiation. Its survival in the Neptunian desert may be due to an unusually high-core mass, or it may have avoided the most intense X-ray irradiation by migrating after the initial activity of its host star had subsided. With a transit depth of 0.13 ± 0.02 per cent, NGTS-4b represents the shallowest transiting system ever discovered from the ground, and is the smallest planet discovered in a wide-field ground-based photometric survey

Reducing SARS-CoV-2 transmission in the UK: A behavioural science approach to identifying options for increasing adherence to social distancing and shielding vulnerable people.

PURPOSE: To describe and discuss a systematic method for producing a very rapid response (3 days) to a UK government policy question in the context of reducing SARS-CoV-2 transmission. METHODS: A group of behavioural and social scientists advising the UK government on COVID-19 contributed to the analysis and writing of advice through the Government Office for Science. The question was as follows: What are the options for increasing adherence to social distancing (staying at home except for essential journeys and work) and shielding vulnerable people (keeping them at home and away from others)? This was prior to social distancing legislation being implemented. The first two authors produced a draft, based on analysis of the current government guidance and the application of the Behaviour Change Wheel (BCW) framework to identify and evaluate the options. RESULTS: For promoting social distancing, 10 options were identified for improving adherence. They covered improvements in ways of achieving the BCW intervention types of education, persuasion, incentivization, and coercion. For promoting shielding of vulnerable people, four options were identified covering the BCW intervention types of incentivization, coercion, and enablement. CONCLUSIONS: Responding to policymakers very rapidly as has been necessary during the COVID-19 pandemic can be facilitated by using a framework to structure the thinking and reporting of multidisciplinary academics and policymakers

Adaptive optics imaging of a stellar occultation by Titan

We present resolved images of the occultation of a binary star by Titan, recorded with the Palomar Observatory adaptive optics system on 20 December 2001 UT. These constitute the first resolved observations of a stellar occultation by a small body, and demonstrate several unique capabilities of diffraction-limited imaging systems for the study of planetary atmospheres. Two refracted stellar images are visible on Titan's limb throughout both events, displaying scintillations due to local density variations. Precise relative astrometry of the refracted stellar images with respect to the unnocculted component of the binary allows us to directly measure their altitude in Titan's atmosphere. Their changing positions also lead to simple demonstration of the finite oblateness of surfaces of constant pressure in Titan's mid-latitude stratosphere, consistent with the only previous measurement of Titan's zonal wind field

Factors associated with wearing a facemask in shops in England following removal of a legal requirement to do so during the COVID-19 pandemic

OBJECTIVES: We aimed to identify psychological factors associated with the use of facemasks in shops in England following removal of legal requirements to do so, and to compare associations with and without legal restrictions. DESIGN: Repeated cross-sectional online surveys (n ≈ 2000 adults) between August 2020 and April 2022 (68,716 responses from 45,682 participants) using quota sampling. METHODS: The outcome measure was whether those who had visited a shop for essentials in the previous seven days reported always having worn a facemask versus sometimes or not at all. Psychological predictor variables included worry, perceived risk and severity of COVID-19 and the perceived effectiveness of facemasks. Socio-demographic variables and measures of clinical vulnerability were also measured. For the period following removal of legal restrictions, multivariable regression was used to assess associations between the primary outcome variable and predictors adjusting for socio-demographic and clinical vulnerability measures. The analysis was repeated including interactions between psychological predictors and presence versus absence of legal restrictions. RESULTS: Worry about COVID-19, beliefs about risks and severity of COVID-19 and effectiveness of facemasks were substantially and independently associated with the use of facemasks. Removal of legal obligations to wear facemasks was associated with a 25% decrease in wearing facemasks and stronger associations between psychological predictors and wearing facemasks. CONCLUSIONS: Legal obligations increase rates of wearing a facemask. Psychological factors associated with wearing a facemask could be targets for interventions aiming to alter rates of wearing a facemask. These interventions may be more effective when there are no legal obligations to wear a face covering in place

Knowledge of Self-Isolation Rules in the UK for Those Who Have Symptoms of COVID-19: A Repeated Cross-Sectional Survey Study

Objectives: To investigate knowledge of self-isolation rules and factors associated with knowledge. Methods: Repeated cross-sectional online surveys (n ≈ 2000 UK adults) between 9 November 2020 and 16 February 2022 (78,573 responses from 51,881 participants). We computed a composite measure of knowledge of self-isolation rules and investigated associations between knowledge and survey wave, socio-demographic characteristics (age, gender, UK nation, index of multiple deprivation), trust in government, and participants’ belief that they had received enough information about self-isolation. Results: In total, 87.9% (95% CI 87.7% to 88.1%, n = 67,288/76,562) of participants knew that if they had symptoms of COVID-19 they should ‘self-isolate’. However, only 62.8% (n = 48,058/76,562, 95% CI 62.4% to 63.1%) knew the main rules regarding what that meant. Younger people had less knowledge than older people, and men had less knowledge than women. Knowledge was lower in people living in England versus in Scotland, Wales, and Northern Ireland. The pattern of association between knowledge and trust in government was unclear. Knowledge was lower in people living in a more deprived area and those who did not believe they had enough information about self-isolation. Knowledge was lower in December 2020 to January 2021, compared with before and after this period. Conclusions: Approximately 63% of UK adults between November 2020 and February 2022 appeared to know the main rules regarding self-isolation if symptomatic with COVID-19. Knowledge was lower in younger than older people, men than women, those living in England compared with Scotland, Wales or Northern Ireland, and those living in more deprived areas

Titan Science with the James Webb Space Telescope (JWST)

The James Webb Space Telescope (JWST), scheduled for launch in 2018, is the successor to the Hubble Space Telescope (HST) but with a significantly larger aperture (6.5 m) and advanced instrumentation focusing on infrared science (0.6-28.0 $\mu$m ). In this paper we examine the potential for scientific investigation of Titan using JWST, primarily with three of the four instruments: NIRSpec, NIRCam and MIRI, noting that science with NIRISS will be complementary. Five core scientific themes are identified: (i) surface (ii) tropospheric clouds (iii) tropospheric gases (iv) stratospheric composition and (v) stratospheric hazes. We discuss each theme in depth, including the scientific purpose, capabilities and limitations of the instrument suite, and suggested observing schemes. We pay particular attention to saturation, which is a problem for all three instruments, but may be alleviated for NIRCam through use of selecting small sub-arrays of the detectors - sufficient to encompass Titan, but with significantly faster read-out times. We find that JWST has very significant potential for advancing Titan science, with a spectral resolution exceeding the Cassini instrument suite at near-infrared wavelengths, and a spatial resolution exceeding HST at the same wavelengths. In particular, JWST will be valuable for time-domain monitoring of Titan, given a five to ten year expected lifetime for the observatory, for example monitoring the seasonal appearance of clouds. JWST observations in the post-Cassini period will complement those of other large facilities such as HST, ALMA, SOFIA and next-generation ground-based telescopes (TMT, GMT, EELT).Comment: 50 pages, including 22 figures and 2 table

Harnessing behavioural science in public health campaigns to maintain 'social distancing' in response to the COVID-19 pandemic: key principles.

Coronavirus Disease 2019 (COVID-19), like Middle East respiratory syndrome (MERS) and severe acute respiratory syndrome (SARS), is an infection arising from a coronavirus. The COVID-19 pandemic is unprecedented in recent times in terms of the global spread of infection and the resultant morbidity, mortality and burden on health systems. In the absence of a vaccine, reducing transmission of the COVID-19 virus requires rapid and extensive behaviour change to enact protective behaviours and ‘social distancing’ across whole populations. Although ‘social distancing’ is the current most used term, it actually refers to maintaining physical separation by reducing the number of times people come into close contact with each other across whole populations. Social distancing applies regardless of infection status and is thus distinctive from quarantine or the isolation of those with suspected or diagnosed infection, which is also an important element of infection control. Governments across the world are implementing a diverse range of interventions to promote adherence to social distancing measures, which include elements of education, persuasion, incentivisation, coercion, environmental restructuring, restriction and enablement. Interventions have been developed rapidly and could not be informed directly by evidence, given the novelty of the virus and rapid spread of the pandemic. Despite this lack of direct evidence, a body of behavioural science exists which can usefully inform the current interventions and promote adherence to these restrictive measures. This body of science has been developed through the study of other infections (including other coronaviruses such as MERS and SARS), other areas of health and other areas of behaviour. This body of science suggests a number of principles which could ensure that interventions are more likely to achieve their intended outcomes and less likely to generate unintended harmful consequences. As a group of behavioural and social scientists who have shared their advice with government through the UK’s Government Office for Science, the researchers of this paper have collaborated to develop a series of principles to inform interventions to promote whole population adherence to social distancing measures. These were informed by members’ expertise and knowledge of existing theory and evidence, rather than by any formal review of the literature

The effectiveness, safety and cost-effectiveness of cytisine versus varenicline for smoking cessation in an Australian population: a study protocol for a randomized controlled non-inferiority trial

Smoking cessation medications are effective but often underutilised because of costs and side effects. Cytisine is a plant-based smoking cessation medication with over 50 years of use in Central and Eastern Europe. While cytisine has been found to be well-tolerated and more effective than nicotine replacement therapy, direct comparison with varenicline have not been conducted. This study evaluates the effectiveness, safety and cost-effectiveness of cytisine compared with varenicline.Two arm, parallel group, randomised, non-inferiority trial, with allocation concealment and blinded outcome assessment.Australian population-based study.Adult daily smokers (N=1266) interested in quitting will be recruited through advertisements and Quitline telephone-based cessation support services.Eligible participants will be randomised (1:1 ratio) to receive either cytisine capsules (25-day supply) or varenicline tablets (12-week supply), prescribed in accordance with the manufacturer's recommended dosing regimen. The medication will be mailed to each participant's nominated residential address. All participants will also be offered standard Quitline behavioural support (up to six 10-12 minute sessions).Assessments will be undertaken by telephone at baseline, 4- and 7-months post-randomisation. Participants will also be contacted twice (two and four weeks post-randomisation) to ascertain adverse events, treatment adherence and smoking status. The primary outcome will be self-reported 6-month continuous abstinence from smoking, verified by carbon monoxide at 7-month follow-up. We will also evaluate the relative safety and cost-effectiveness of cytisine compared with varenicline. Secondary outcomes will include self-reported continuous and 7-day point prevalence abstinence and cigarette consumption at each follow-up interview.If cytisine is as effective as varenicline, its lower cost and natural plant-based composition may make it an acceptable and affordable smoking cessation medication that could save millions of lives worldwide

Droplet actuator analyzer with cartridge

A droplet actuator with cartridge is provided. According to one embodiment, a sample analyzer is provided and includes an analyzer unit comprising electronic or optical receiving means, a cartridge comprising self-contained droplet handling capabilities, and a wherein the cartridge is coupled to the analyzer unit by a means which aligns electronic and/or optical outputs from the cartridge with electronic or optical receiving means on the analyzer unit. According to another embodiment, a sample analyzer is provided and includes a sample analyzer comprising a cartridge coupled thereto and a means of electrical interface and/or optical interface between the cartridge and the analyzer, whereby electrical signals and/or optical signals may be transmitted from the cartridge to the analyzer