12 research outputs found

    Planet Hunters. VIII. Characterization of 41 Long-Period Exoplanet Candidates from Kepler Archival Data

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    The census of exoplanets is incomplete for orbital distances larger than 1 AU. Here, we present 41 long-period planet candidates in 38 systems identified by Planet Hunters based on Kepler archival data (Q0-Q17). Among them, 17 exhibit only one transit, 14 have two visible transits and 10 have more than three visible transits. For planet candidates with only one visible transit, we estimate their orbital periods based on transit duration and host star properties. The majority of the planet candidates in this work (75%) have orbital periods that correspond to distances of 1-3 AU from their host stars. We conduct follow-up imaging and spectroscopic observations to validate and characterize planet host stars. In total, we obtain adaptive optics images for 33 stars to search for possible blending sources. Six stars have stellar companions within 4". We obtain high-resolution spectra for 6 stars to determine their physical properties. Stellar properties for other stars are obtained from the NASA Exoplanet Archive and the Kepler Stellar Catalog by Huber et al. (2014). We validate 7 planet candidates that have planet confidence over 0.997 (3-{\sigma} level). These validated planets include 3 single-transit planets (KIC-3558849b, KIC-5951458b, and KIC-8540376c), 3 planets with double transits (KIC-8540376b, KIC-9663113b, and KIC-10525077b), and 1 planet with 4 transits (KIC-5437945b). This work provides assessment regarding the existence of planets at wide separations and the associated false positive rate for transiting observation (17%-33%). More than half of the long-period planets with at least three transits in this paper exhibit transit timing variations up to 41 hours, which suggest additional components that dynamically interact with the transiting planet candidates. The nature of these components can be determined by follow-up radial velocity and transit observations.Comment: Published on ApJ, 815, 127 Notations of validated planets are changed in accordance with naming convention of NASA Exoplanet Archiv

    Making the American mouth: Dental professionalization, dental public health, and the construction of identity in the 20<super>th</super> century United States.

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    The professionalization of dentistry in the 20th century United States was linked to changing constructions of what standards of dentistry and dental appearance were American. In turn, debates about oral health care constituted an important site for the construction of national identity. This dissertation treats American dentists' professional writings as a body of cultural history source material, examining them for evidence of how dentists participated in the construction of professional, national, and other identities in the twentieth century. Where possible, I also elucidate patients' responses to dentists' concepts of appropriate patient and citizenship behaviors. In the early 20th century, American dentists used travel writing to represent American dentistry as entailing uniquely high levels of skill, intellect, and scientific savvy. However, in their discussions of the American diet, dentists debated with considerable anxiety what it meant to be American, and whether that was good or bad for oral health. Dentists' shifting professional and entrepreneurial interests also shaped their ideas about the delivery of dental care---particularly the provision of public funding for dental public health measures, including public school dental hygiene programs and the fluoridation of public water supplies. By the end of the twentieth century, pressures from within and outside the profession left dentists increasingly suspicious of public health programs they had previously supported. In response, they developed and expanded treatment measures (such as orthodonture) that required long-term time and financial commitments on the part of the individual patient. By the end of the twentieth century, good citizenship, to most dentists, came to mean the promotion of private practice, and opposition to publicly-funded health programs (and to most dental insurance). Increasingly, good citizenship was marked in patients' mouths by evidence that they had obtained costly esthetic dental interventions: absence of these markers was often attributed to lack of individual ambition, or to an inappropriately low valuation of personal appearance and its role in business and social life.Ph.D.American historyDentistryHealth and Environmental SciencesPublic healthScience historySocial SciencesUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/124160/2/3122024.pd

    Proximity to parental symptom onset and amyloid-β burden in sporadic Alzheimer disease

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    IMPORTANCE Alzheimer disease (AD) develops during several decades. Presymptomatic individuals might be the best candidates for clinical trials, but their identification is challenging because they have no symptoms. OBJECTIVE To assess whether a sporadic parental estimated years to symptom onset calculation could be used to identify information about amyloid-β (Aβ) levels in asymptomatic individuals with a parental history of AD dementia. DESIGN, SETTING, AND PARTICIPANTS This cohort study analyzed Aβ1-42 in cerebrospinal fluid (CSF) specimens from 101 cognitively normal individuals who had a lumbar puncture as part of the Presymptomatic Evaluation of Novel or Experimental Treatments for Alzheimer Disease (PREVENT-AD) cohort from September 1, 2011, through November 30, 2016 (374 participants were enrolled in the cohort during this period). The study estimated each participant's proximity to his/her parent's symptom onset by subtracting the index relative's onset age from his/her current age. The association between proximity to parental symptom onset and Aβ levels was then assessed using apolipoprotein E ϵ4 (APOE4) status and sex as interactive terms. These analyses were performed again in 2 independent cohorts using CSF and Pittsburgh compound B carbon 11-labeled positron emission tomography (PIB-PET) Aβ biomarkers: the Adult Children Study (ACS) and the Wisconsin Registry for Alzheimer Prevention (WRAP) cohorts. MAIN OUTCOMES AND MEASURES The association between proximity to parental symptom onset and Aβ burden in asymptomatic individuals with a parental history of sporadic AD. RESULTS The present analysis included a subset of 101 PREVENT-AD individuals (mean [SD] age, 61.8 [5.1] years; 30 [29.7%] male), 128 ACS participants (112 participants underwent CSF measurement: mean [SD] age, 63.4 [5.1] years; 31 [27.7%] male; and 107 underwent PIB-PET: mean [SD] age, 64.6 [5.3] years; 27 [25.2%] male), and 135 WRAP participants (85 participants underwent CSF measurement: mean [SD] age, 59.9 [6.0] years; 27 [31.8%] male; and 135 underwent PIB-PET: mean [SD] age, 59.6 [6.1] years; 43 [31.9%] male). In the PREVENT-AD cohort, individuals approaching their parent's onset age had lower CSF Aβ1-42 levels (range, 402-1597; B = -9.09, P = .04). This association was stronger in APOE4 carriers (B = -17.9, P = .03) and women (B = -19.8, P = .02). In the ACS cohort, the main association was replicated using PIB-PET data, and the sex interaction was replicated using CSF and PIB-PET data. In the WRAP cohort, the results were not replicated using cross-sectional data, but the main association and the APOE interaction were replicated using PIB-PET longitudinal data. CONCLUSIONS AND RELEVANCE These results suggest that proximity to parental symptom onsetmay help estimate Aβ biomarker changes in women or APOE4 carrier asymptomatic individuals with a parental history of sporadic AD
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