A Radial Velocity Study of the Planetary System of Pi Mensae: Improved Planet Parameters for PI Mensae c and a Third Planet on a 125-d Orbit

Pi Men hosts a transiting planet detected by the TESS space mission and an outer planet in a 5.7-yr orbit discovered by RV surveys. We studied this system using new radial velocity (RV) measurements taken with the HARPS spectrograph on ESO's 3.6-m telescope as well as archival data. We constrain the stellar RV semi-amplitude due to the transiting planet, Pi Men c, as K_c = 1.21 +/- 0.12 m/s resulting in a planet mass of M_c = 3.63 +/- 0.38 M_Earth. A planet radius of R_c= 2.145 +/- 0.015 R_Earth yields a bulk density of rho = 2.03 +/- 0.22 g/cm^{-3}. The precisely determined density of this planet and the brightness of the host star make Pi Men c an excellent laboratory for internal structure and atmospheric characterization studies. Our HARPS RV measurements also reveal compelling evidence for a third body, PI Men d, with a minimum mass M sin i = 13.38 +/- 1.35 M_Earth orbiting with a period of P_d = 125 d on an eccentric orbit (e = 0.22). A simple dynamical analysis indicates that the orbit of Pi Men d is stable on timescales of at least 20 Myrs. Given the mutual inclination between the outer gaseous giant and the inner rocky planet and the presence of a third body at 125 d, Pi Men is an important planetary system for dynamical and formation studies.Comment: Accepted for publication in the Astronomical Journal. 40 pages, 16 figure

Evaluating the incidence of pathological complete response in current international rectal cancer practice: the barriers to widespread safe deferral of surgery

This is the peer reviewed version of the following article: , which has been published in final form at https://doi.org/10.1111/codi.14361. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions."Colorectal Disease © 2018 The Association of Coloproctology of Great Britain and Ireland Introduction: The mainstay of management for locally advanced rectal cancer is chemoradiotherapy followed by surgical resection. Following chemoradiotherapy, a complete response may be detected clinically and radiologically (cCR) prior to surgery or pathologically after surgery (pCR). We aim to report the overall complete pathological response (pCR) rate and the reliability of detecting a cCR by conventional pre-operative imaging. Methods: A pre-planned analysis of the European Society of Coloproctology (ESCP) 2017 audit was performed. Patients treated by elective rectal resection were included. A pCR was defined as a ypT0 N0 EMVI negative primary tumour; a partial response represented any regression from baseline staging following chemoradiotherapy. The primary endpoint was the pCR rate. The secondary endpoint was agreement between post-treatment MRI restaging (yMRI) and final pathological staging. Results: Of 2572 patients undergoing rectal cancer surgery in 277 participating centres across 44 countries, 673 (26.2%) underwent chemoradiotherapy and surgery. The pCR rate was 10.3% (67/649), with a partial response in 35.9% (233/649) patients. Comparison of AJCC stage determined by post-treatment yMRI with final pathology showed understaging in 13% (55/429) and overstaging in 34% (148/429). Agreement between yMRI and final pathology for T-stage, N-stage, or AJCC status were each graded as ‘fair’ only (n = 429, Kappa 0.25, 0.26 and 0.35 respectively). Conclusion: The reported pCR rate of 10% highlights the potential for non-operative management in selected cases. The limited strength of agreement between basic conventional post-chemoradiotherapy imaging assessment techniques and pathology suggest alternative markers of response should be considered, in the context of controlled clinical trials