Science with an ngVLA: Observing the Effects of Chemistry on Exoplanets and Planet Formation

One of the primary mechanisms for inferring the dynamical history of planets in our Solar System and in exoplanetary systems is through observation of elemental ratios (i.e. C/O). The ability to effectively use these observations relies critically on a robust understanding of the chemistry and evolutionary history of the observed abundances. Significant efforts have been devoted to this area from within astrochemistry circles, and these efforts should be supported going forward by the larger exoplanetary science community. In addition, the construction of a next-generation radio interferometer will be required to test many of these predictive models in situ, while simultaneously providing the resolution necessary to pinpoint the location of planets in formation.Comment: To be published in the ASP Monograph Series, "Science with a Next-Generation VLA", ed. E. J. Murphy (ASP, San Francisco, CA

Survey of Cold Water Lines in Protoplanetary Disks: Indications of Systematic Volatile Depletion

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Detecting a Young 2 Jupiter Mass Planet Embedded in the Disk of HD 163296

To directly confront planet formation mechanisms, a sample of objects in the earliest stages of their lives, i.e, when they are still embedded in their natal protoplanetary disks, need to be observed and studied. Here we propose to demonstrate a synergistic approach between the Atacama Large Millimeter/submillimeter Array (ALMA) and the James Webb Space Telescope (JWST). ALMA observations can reveal the location of an embedded planet by its influence on the dynamical structure of the protoplanetary disk, while the strength of these perturbations allow for a tight constraint on the mass of the planet. Here we propose to image for the first time an embedded planet in the disk around HD 163296 using the MIRI instrument onboard JWST. The 2 MJup planet has been detected in several, independent studies and lies 2" north of the host star. JWST/MIRI in coronagraphic mode at 11.4 $\mu$m is the only available option to detect such embedded objects for decades to come, as no other instrument has the mid-infrared high-contrast capabilities necessary to overcome the obstacle of disk absorption prevalent at shorter, NIR wavelengths. Given its mass and separation, the planet around HD163296 offers the highest chances of detection and would pave the path for a new and highly efficient exoplanet detection method. Detecting emission from the planet and its surrounding is going to reshape our understanding of planet formation, allowing for direct comparison between formation scenarios

Detecting a Young 2 Jupiter Mass Planet Embedded in the Disk of HD 163296

To directly confront planet formation mechanisms, a sample of objects in the earliest stages of their lives, i.e, when they are still embedded in their natal protoplanetary disks, need to be observed and studied. Here we propose to demonstrate a synergistic approach between the Atacama Large Millimeter/submillimeter Array (ALMA) and the James Webb Space Telescope (JWST). ALMA observations can reveal the location of an embedded planet by its influence on the dynamical structure of the protoplanetary disk, while the strength of these perturbations allow for a tight constraint on the mass of the planet. Here we propose to image for the first time an embedded planet in the disk around HD 163296 using the MIRI instrument onboard JWST. The 2 MJup planet has been detected in several, independent studies and lies 2" north of the host star. JWST/MIRI in coronagraphic mode at 11.4 $\mu$m is the only available option to detect such embedded objects for decades to come, as no other instrument has the mid-infrared high-contrast capabilities necessary to overcome the obstacle of disk absorption prevalent at shorter, NIR wavelengths. Given its mass and separation, the planet around HD163296 offers the highest chances of detection and would pave the path for a new and highly efficient exoplanet detection method. Detecting emission from the planet and its surrounding is going to reshape our understanding of planet formation, allowing for direct comparison between formation scenarios

Long-term safety and efficacy of emtricitabine and tenofovir alafenamide vs emtricitabine and tenofovir disoproxil fumarate for HIV-1 pre-exposure prophylaxis: week 96 results from a randomised, double-blind, placebo-controlled, phase 3 trial

In DISCOVER, a multinational, randomised controlled trial, emtricitabine and tenofovir alafenamide compared with emtricitabine and tenofovir disoproxil fumarate showed non-inferior efficacy for HIV prevention and improved bone mineral density and renal safety biomarkers at week 48. We report outcomes analysed after all participants had completed 96 weeks of follow-up. This study is an ongoing, randomised, double-blind, multicentre, active-controlled, phase 3, non-inferiority trial done at 94 community, public health, and hospital-associated clinics located in Europe and North America. Adult cisgender men and transgender women who have sex with men, both with a high risk of acquiring HIV as determined by self-reported sexual behaviour or recent sexually transmitted infections, were randomly assigned (1:1) to receive either emtricitabine and tenofovir alafenamide (200/25 mg) tablets daily, with matched placebo tablets (emtricitabine and tenofovir alafenamide group), or emtricitabine and tenofovir disoproxil fumarate (200/300 mg) tablets daily, with matched placebo tablets (emtricitabine and tenofovir disoproxil fumarate group). The primary efficacy outcome was incident HIV infection. Incidence of HIV-1 infection per 100 person-years was assessed when the last participant had completed 96 weeks of follow-up. This trial is registered with ClinicalTrials.gov, number NCT02842086. Between Sept 13, 2016, and June 30, 2017, 5387 participants were randomly assigned to receive emtricitabine and tenofovir alafenamide (n=2694) or emtricitabine and tenofovir disoproxil fumarate (n=2693), contributing 10 081 person-years of follow-up. At 96 weeks of follow-up, there were eight HIV infections in participants who had received emtricitabine and tenofovir alafenamide (0·16 infections per 100 person-years [95% CI 0·07–0·31]) and 15 in participants who had received emtricitabine and tenofovir disoproxil fumarate (0·30 infections per 100 person-years [0·17–0·49]). Emtricitabine and tenofovir alafenamide maintained its non-inferiority to emtricitabine and tenofovir disoproxil fumarate for HIV prevention (IRR 0·54 [95% CI 0·23–1·26]). Approximately 78–82% of participants reported taking study medication more than 95% of the time across all study visits. Rates of sexually transmitted infections remained high and similar across groups (21 cases per 100 person-years for rectal gonorrhoea and 28 cases per 100 person-years for rectal chlamydia). Emtricitabine and tenofovir alafenamide continued to show superiority over emtricitabine and tenofovir disoproxil fumarate in all but one of the six prespecified bone mineral density and renal biomarkers. There was more weight gain among participants who had received emtricitabine and tenofovir alafenamide (median weight gain 1·7 kg vs 0·5 kg, p<0·0001). Emtricitabine and tenofovir alafenamide is safe and effective for longer-term pre-exposure prophylaxis in cisgender men and transgender women who have sex with men. Gilead Sciences

Implementing stakeholder engagement to explore alternative models of consent: An example from the PREP-IT trials

Introduction: Cluster randomized crossover trials are often faced with a dilemma when selecting an optimal model of consent, as the traditional model of obtaining informed consent from participant's before initiating any trial related activities may not be suitable. We describe our experience of engaging patient advisors to identify an optimal model of consent for the PREP-IT trials. This paper also examines surrogate measures of success for the selected model of consent. Methods: The PREP-IT program consists of two multi-center cluster randomized crossover trials that engaged patient advisors to determine an optimal model of consent. Patient advisors and stakeholders met regularly and reached consensus on decisions related to the trial design including the model for consent. Patient advisors provided valuable insight on how key decisions on trial design and conduct would be received by participants and the impact these decisions will have. Results: Patient advisors, together with stakeholders, reviewed the pros and cons and the requirements for the traditional model of consent, deferred consent, and waiver of consent. Collectively, they agreed upon a deferred consent model, in which patients may be approached for consent after their fracture surgery and prior to data collection. The consent rate in PREP-IT is 80.7%, and 0.67% of participants have withdrawn consent for participation. Discussion: Involvement of patient advisors in the development of an optimal model of consent has been successful. Engagement of patient advisors is recommended for other large trials where the traditional model of consent may not be optimal