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Searching for Transit Timing Variations and Fitting a New Ephemeris to Transits of TrES-1 b
Paige Yeung,Quinn Perian,Peyton Robertson,Michael Fitzgerald,Martin Fowler,Frank Sienkiewicz,Kalee Tock 한국천문학회 2022 Journal of The Korean Astronomical Society Vol.55 No.4
Based on the light an exoplanet blocks from its host star as it passes in front of it during a transit, the mid-transit time can be determined. Periodic variations in mid-transit times can indicate another planet's gravitational influence. We investigate 83 transits of TrES-1 b as observed from 6-inch telescopes in the MicroObservatory robotic telescope network. The EXOTIC data reduction pipeline is used to process these transits, fit transit models to light curves, and calculate transit midpoints. This paper details the methodology for analyzing transit timing variations (TTVs) and using transit measurements to maintain ephemerides. The application of Lomb-Scargle period analysis for studying the plausibility of TTVs is explained. The analysis of the resultant TTVs from 46 transits from MicroObservatory and 47 transits from archival data in the Exoplanet Transit Database indicated the possible existence of other planets affecting the orbit of TrES-1 and improved the precision of the ephemeris by one order of magnitude. We now estimate the ephemeris to be 2455489.66026 BJD_{TDB} ± 0.00044 d + (3.0300689 ± 0.0000007) d × epoch. This analysis also demonstrates the role of small telescopes in making precise mid-transit time measurements, which can be used to help maintain ephemerides and perform TTV analysis. The maintenance of ephemerides allows for an increased ability to optimize telescope time on large ground-based telescopes and space telescope missions.
McGovern, David A.,Doorley, Gerard W.,Whelan, Aine M.,Parker, Anthony W.,Towrie, Michael,Kelly, John M.,Quinn, Susan J. Korean Society of Photoscience 2009 Photochemical & photobiological sciences Vol.8 No.4
The photophysical properties of 5'-guanosine monophosphate (5'-GMP) and polyguanylic acid {poly(G)} in $D_2O$ solutions of varying pH have been studied using picosecond transient infrared absorption spectroscopy. Whereas in neutral or weakly alkaline solution only the vibrationally excited electronic ground state of 5'-GMP is observed, in acidic solution the relatively long-lived ($229{\pm}20\;ps$) electronic excited state of protonated 5'-GMP, which possesses strong absorptions at 1517 and $1634\;cm^{-1}$, could be detected. The picosecond transient behaviour of polyguanylic acid in acidic solution is also very different from that of the polynucleotide in neutral solution due not only to the protonation of guanine moieties yielding the protonated excited state but because of the disruption of the guanine stacks which are present in the species in neutral solution.
Endometrial cancer risk and survival by tumor MMR status
Christina M. Nagle,Christina M. Nagle,Tracy A. O'Mara,Yen Tan,Daniel D. Buchanan,Andreas Obermair,Penny Blomfield,Michael A. Quinn,Penelope M. Webb,Amanda B. Spurdle,Australian Endometrial Cancer Stud 대한부인종양학회 2018 Journal of Gynecologic Oncology Vol.29 No.3
Objective: The risk of developing endometrial cancer (EC) and/or survival following a diagnosis of EC might differ by tumor DNA mismatch repair (MMR) status. We assessed the association between tumor MMR status (classified as MMR-proficient, somatic MMR-deficient, germline MMR-deficient) and the risk of developing EC and survival following a diagnosis of EC. Methods: We analyzed data from women who participated in the Australian National Endometrial Cancer Study (ANECS) conducted between 2005 and 2007. Risk analyses (698 cases/691 population controls) utilized sociodemographic and lifestyle information obtained from telephone interviews at recruitment. For survival analyses (728 cases), patients' clinical data was abstracted from medical records, and survival data were obtained via linkage with the Australian National Death Index. We used logistic regression analysis to evaluate the associations between tumor MMR status and EC risk, and proportional hazards models to perform survival analyses with adjustment of known prognostic factors. Results: Established risk factors for EC did not differ significantly by tumor MMR status. In analyses including all EC subtypes, overall and EC-specific survival did not differ by tumor MMR status. Among women with the most common endometrioid subtype, EC-specific survival was worse for women with somatic MMR-deficient EC compared to women with MMR-proficient EC (hazard ratio [HR]=2.18; 95% confidence interval [CI]=1.19–4.01). Conclusion: The risk of EC is not associated with MMR status. Accurate separation of germline from somatic causes of MMR deficiency suggests that patients with endometrioid subtype somatic MMR-deficient tumors have poorer EC-specific survival than those with MMR-proficient tumors, after accounting for other prognostic factors.