Constraining Orbital Periods from Nonconsecutive Observations: Period Estimates for Long-Period Planets in Six Systems Observed by K2 During Multiple Campaigns

Most planetary discoveries with the K2 and TESS missions are restricted to short periods because of the limited duration of observation. However, the re-observation of sky area allows for the detection of longer period planets. We describe new transits detected in six candidate planetary systems which were observed by multiple K2 mission campaigns. One of these systems is a multiplanet system with four candidate planets; we present new period constraints for two planets in this system. In the other five systems, only one transit is observed in each campaign, and we derive period constraints from this new data. The period distributions are highly multimodal resulting from missed potential transits in the gap between observations. Each peak in the distribution corresponds to transits at an integer harmonic of the two observed transits. We further detail a generalized procedure to constrain the period for planets with multiple observations with intervening gaps. Because long period photometrically discovered planets are rare, these systems are interesting targets for follow-up observations and confirmation. Specifically, all six systems are bright enough (V = 10.4-12.7) to be amenable to radial velocity follow-up. This work serves as a template for period constraints in a host of similar yet-to-be-discovered planets in long baseline, temporally gapped observations conducted by the TESS mission.Comment: 10 pages, 5 figures; accepted for publication in A

The microbiota-gut-brain axis:An emerging therapeutic target in chemotherapy-induced cognitive impairment

Chemotherapy-induced cognitive impairment (CICI) is an ill-defined complication of chemotherapy treatment that places a significant psychosocial burden on survivors of cancer and has a considerable impact on the activities of daily living. CICI pathophysiology has not been clearly defined, with candidate mechanisms relating to both the direct cytotoxicity of chemotherapy drugs on the central nervous system (CNS) and more global, indirect mechanisms such as neuroinflammation and blood brain barrier (BBB) damage. A growing body of research demonstrates that changes to the composition of the gastrointestinal microbiota is an initiating factor in numerous neurocognitive conditions, profoundly influencing both CNS immunity and BBB integrity. Importantly, chemotherapy causes significant disruption to the gastrointestinal microbiota. While microbial disruption is a well-established factor in the development of chemotherapy-induced gastrointestinal toxicities (largely diarrhoea), its role in CICI remains unknown, limiting microbial-based therapeutics or risk prediction strategies. Therefore, this review aims to synthesise and critically evaluate the evidence addressing the microbiota-gut-brain axis as a critical factor influencing the development of CICI

Size Gap for Zero Temperature Black Holes in Semiclassical Gravity

We show that a gap exists in the allowed sizes of all zero temperature static spherically symmetric black holes in semiclassical gravity when only conformally invariant fields are present. The result holds for both charged and uncharged black holes. By size we mean the proper area of the event horizon. The range of sizes that do not occur depends on the numbers and types of quantized fields that are present. We also derive some general properties that both zero and nonzero temperature black holes have in all classical and semiclassical metric theories of gravity.Comment: 4 pages, ReVTeX, no figure

A Closer Look at Exoplanet Occurrence Rates: Considering the Multiplicity of Stars without Detected Planets

One core goal of the Kepler mission was to determine the frequency of Earth-like planets that orbit Sun-like stars. Accurately estimating this planet occurrence rate requires both a well-vetted list of planets and a clear understanding of the stars searched for planets. Previous ground-based follow-up observations have, through a variety of methods, sought to improve our knowledge of stars that are known to host planets. Kepler targets without detected planets, however, have not been subjected to the same intensity of follow-up observations. In this paper, we constrain better the stellar multiplicity for stars around which Kepler could have theoretically detected a transiting Earth-sized planet in the habitable zone. We subsequently aim to improve estimates of the exoplanet search completeness—the fraction of exoplanets that were detected by Kepler—with our analysis. By obtaining adaptive optics observations of 71 Kepler target stars from the Shane 3 m telescope at Lick Observatory, we detected 14 candidate stellar companions within 4'' of 13 target stars. Of these 14 candidate stellar companions, we determine through multiple independent methods that 3 are likely to be bound to their corresponding target star. We then assess the impact of our observations on exoplanet occurrence rate calculations, finding an increase in occurrence of 6% (0.9σ) for various estimates of the frequency of Earth-like planets and an increase of 26% (4.5σ) for super-Earths and sub-Neptunes. These occurrence increases are not entirely commensurate with theoretical predictions, though this discrepancy may be due to differences in the treatment of stellar binarity

Federal Research, Additional Actions Needed to Improve Public Access to Research Results: Report to Congressional Requesters [with Responses from Federal Agencies]

Why GAO Did This Study Research and development helps catalyze breakthroughs that improve the overall health and wellbeing of our society. Federal research and development expenditures averaged about $135 billion annually for fiscal years 2015 to 2017. According to OSTP, providing free public access to federally funded research results can improve both the impact and accountability of this important federal investment. In February 2013, OSTP directed federal agencies with more than$100 million in annual research and development expenditures to develop a plan to support increased public access to the results of federally funded research. GAO was asked to examine public access to federally funded research results. This report examines the extent of agencies’ (1) progress implementing plans to increase public access to federally funded research results and (2) coordination on public access plan implementation. GAO administered a questionnaire to 19 federal agencies selected based on annual research and development expenditure amounts, among other criteria; reviewed agency documents; and interviewed officials from 11 agencies, OSTP, and 21 stakeholder organizations. What GAO Found The 19 agencies that GAO reviewed have made progress implementing their plans to increase public access to federally funded research results (publications and data), as called for in a 2013 Office of Science and Technology Policy (OSTP) memorandum. However, some agencies have not fully implemented some aspects of their plans, in particular those related to data access and mechanisms to ensure researchers comply with public access requirements. Agencies are coordinating with each other and with nonfederal stakeholders to implement public access plans, including through an interagency group led by OSTP and five other agencies. However, the group has not fully implemented selected leading practices identified by GAO that can enhance and sustain interagency collaboration, such as defining and articulating common outcomes. For example, according to OSTP staff, key outcomes have not yet been decided upon. Agency officials and stakeholders identified several challenges to implementing public access plans that interagency coordination might help them address, such as • Absence of common standards in several areas; • Measuring effectiveness of public access plan implementation; and • Balancing providing public access with safeguarding sensitive information. By taking steps to fully implement relevant leading collaboration practices, the interagency group could help agencies better marshal their collective efforts to address common challenges to public access plan implementation. What GAO Recommends GAO is making 37 recommendations to 16 agencies to promote full and effective implementation of agency public access plans. For example, GAO recommends that OSTP and 5 agencies leading a public access interagency group take steps to fully implement selected leading collaboration practices. Of the 16 agencies, 15 agreed with GAO’s recommendations while 1 (OSTP) disagreed. GAO continues to believe the recommendation to OSTP is warranted