Transit Timing Observations from Kepler: VI. Transit Timing Variation Candidates in the First Seventeen Months from Polynomial Models

Transit timing variations provide a powerful tool for confirming and characterizing transiting planets, as well as detecting non-transiting planets. We report the results an updated TTV analysis for 1481 planet candidates (Borucki et al. 2011; Batalha et al. 2012) based on transit times measured during the first sixteen months of Kepler observations. We present 39 strong TTV candidates based on long-term trends (2.8% of suitable data sets). We present another 136 weaker TTV candidates (9.8% of suitable data sets) based on excess scatter of TTV measurements about a linear ephemeris. We anticipate that several of these planet candidates could be confirmed and perhaps characterized with more detailed TTV analyses using publicly available Kepler observations. For many others, Kepler has observed a long-term TTV trend, but an extended Kepler mission will be required to characterize the system via TTVs. We find that the occurrence rate of planet candidates that show TTVs is significantly increased (~68%) for planet candidates transiting stars with multiple transiting planet candidate when compared to planet candidates transiting stars with a single transiting planet candidate.Comment: Accepted to ApJ; 9 pages, incl. 3 B&W figures, 1 table, 2 electronic datasets available as ancillary files; Includes analyses of more planet candidates; Transit times and additional figures at http://www.astro.ufl.edu/~eford/data/kepler

Architecture and Dynamics of Kepler's Candidate Multiple Transiting Planet Systems

About one-third of the ~1200 transiting planet candidates detected in the first four months of \ik data are members of multiple candidate systems. There are 115 target stars with two candidate transiting planets, 45 with three, 8 with four, and one each with five and six. We characterize the dynamical properties of these candidate multi-planet systems. The distribution of observed period ratios shows that the vast majority of candidate pairs are neither in nor near low-order mean motion resonances. Nonetheless, there are small but statistically significant excesses of candidate pairs both in resonance and spaced slightly too far apart to be in resonance, particularly near the 2:1 resonance. We find that virtually all candidate systems are stable, as tested by numerical integrations that assume a nominal mass-radius relationship. Several considerations strongly suggest that the vast majority of these multi-candidate systems are true planetary systems. Using the observed multiplicity frequencies, we find that a single population of planetary systems that matches the higher multiplicities underpredicts the number of singly-transiting systems. We provide constraints on the true multiplicity and mutual inclination distribution of the multi-candidate systems, revealing a population of systems with multiple super-Earth-size and Neptune-size planets with low to moderate mutual inclinations.Comment: 27 pages, 19 figures, 8 tables, emulateapj style. Accepted to ApJ. This version includes several minor changes to the tex

Management of internal fistulas in Crohn's disease

Internal fistulas occur in 5-10% of patients with Crohn's disease. The clinical presentation of each of the three main types of internal fistulas--enteroenteric, enterovaginal, and enterovesical fistulas--is important in determining the best management. Asymptomatic fistulas usually require no treatment, but fistulas that cause severe or persistent symptoms necessitate intervention. Previously regarded as a surgical condition requiring resection, some internal fistulas are amenable to a more conservative approach involving medical therapy, surgical repair, or both. So far, there have not been any prospective studies designed specifically to assess the efficacy of a medical treatment of internal fistulas, and information about treatment results is gleaned from trials in which patients with internal fistulas have been included and from retrospective reports. Drugs that have been reported to close internal fistulas partially or completely include azathioprine, 6-mercaptopurine, mycophenolate mofetil, cyclosporine A, tacrolimus, and infliximab. Reparative surgical techniques include transrectal and transvaginal mucosal advancement flaps, cutaneous advancement flap, and anal stricturectomy in combination with a rectal mucosal advancement sleeve. Prospective trials of medical therapy and combination medical and surgical therapy for internal fistulas are needed to provide evidence to support the use of these new therapeutic approaches