Factors Influencing Pediatric Dental Program Directorsâ Selection of Residents and Demographics of Current Directors

The primary goal of this study was to examine the criteria that influence rankings of candidates by advanced education program directors in pediatric dentistry. Secondary objectives were to obtain information on the resident selection process and to explore demographics of current program directors. A survey was sent in 2005 to all sixtyâ three program directors of pediatric dentistry residency programs accredited within the United States for the graduating class of 2007. The survey had a response rate of almost 78 percent (49/63). Respondents were requested to rank the importance of eleven factors that are typically included in the selection criteria for pediatric dentistry residents. Factors were rated on a scale of critical, very important, fairly important, somewhat important, and not important. The four highest ranked criteria by program directors were the following, in order: National Board scores, dental school clinical grades, class rank, and grade point average (GPA). Other factors ranked in descending order of perceived importance were the following: dental school basic science grades, experience in pediatric dentistry, extracurricular activities, completion of a general practice residency or advanced education in general dentistry program, the application essay, a publication or professional presentation, and private practice experience. All directors ranked personal interviews as very important to critical. Letters of recommendation from a pediatric dentistry department chairperson or faculty member were viewed more favorably than letters from dental school deans and nonâ pediatric dentistry faculty. Fiftyâ seven percent of the directors responding (28/49) were male, and 81 percent (40/49) were white, nonâ Hispanic. Fiftyâ nine percent of the directors (29/49) graduated from a residency program over twenty years ago, with 39 percent (19/49) having been a director for less than five years.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/153594/1/jddj002203372009733tb04706x.pd

Elemental Abundances of Kepler Objects of Interest in APOGEE. I. Two Distinct Orbital Period Regimes Inferred from Host Star Iron Abundances

The Apache Point Observatory Galactic Evolution Experiment (APOGEE) has observed $\sim$600 transiting exoplanets and exoplanet candidates from \textit{Kepler} (Kepler Objects of Interest, KOIs), most with $\geq$18 epochs. The combined multi-epoch spectra are of high signal-to-noise (typically $\geq$100) and yield precise stellar parameters and chemical abundances. We first confirm the ability of the APOGEE abundance pipeline, ASPCAP, to derive reliable [Fe/H] and effective temperatures for FGK dwarf stars -- the primary \textit{Kepler} host stellar type -- by comparing the ASPCAP-derived stellar parameters to those from independent high-resolution spectroscopic characterizations for 221 dwarf stars in the literature. With a sample of 282 close-in ($P<100$ days) KOIs observed in the APOGEE KOI goal program, we find a correlation between orbital period and host star [Fe/H] characterized by a critical period, $P_\mathrm{crit}$= $8.3^{+0.1}_{-4.1}$ days, below which small exoplanets orbit statistically more metal-enriched host stars. This effect may trace a metallicity dependence of the protoplanetary disk inner-radius at the time of planet formation or may be a result of rocky planet ingestion driven by inward planetary migration. We also consider that this may trace a metallicity dependence of the dust sublimation radius, but find no statistically significant correlation with host $T_\mathrm{eff}$ and orbital period to support such a claim.Comment: 18 Pages, Accepted to A

TOI-150: A transiting hot Jupiter in the TESS southern CVZ

We report the detection of a hot Jupiter ($M_{p}=1.75_{-0.17}^{+0.14}\ M_{J}$,$R_{p}=1.38\pm0.04\ R_{J}$) orbiting a middle-aged star ($\log g=4.152^{+0.030}_{-0.043}$) in the Transiting Exoplanet Survey Satellite (TESS) southern continuous viewing zone ($\beta=-79.59^{\circ}$). We confirm the planetary nature of the candidate TOI-150.01 using radial velocity observations from the APOGEE-2 South spectrograph and the Carnegie Planet Finder Spectrograph, ground-based photometric observations from the robotic Three-hundred MilliMeter Telescope at Las Campanas Observatory, and Gaia distance estimates. Large-scale spectroscopic surveys, such as APOGEE/APOGEE-2, now have sufficient radial velocity precision to directly confirm the signature of giant exoplanets, making such data sets valuable tools in the TESS era. Continual monitoring of TOI-150 by TESS can reveal additional planets and subsequent observations can provide insights into planetary system architectures involving a hot Jupiter around a star about halfway through its main-sequence life.Comment: 13 pages, 3 figures, 2 tables, accepted to ApJ

VARIABLE STARS in the FIELD of the HYDRA II ULTRA-FAINT DWARF GALAXY

We report the discovery of one RR Lyrae star in the ultra-faint satellite galaxy Hydra II based on time series photometry in the g, r and i bands obtained with the Dark Energy Camera at Cerro Tololo Inter-American Observatory, Chile. The association of the RR Lyrae star discovered here with Hydra II is clear because is located at 42″ from the center of the dwarf, well within its half-light radius of 102″. The RR Lyrae star has a mean magnitude of i= 21.30 ± 0.04 which is too faint to be a field halo star. This magnitude translates to a heliocentric distance of 151 ± 8 kpc for Hydra II; this value is ∼13%larger than the estimate from the discovery paper based on the average magnitude of several blue horizontal branch star candidates. The new distance implies a slightly larger half-light radius of 76+12 -10pc and a brighter absolute magnitude of Mv = -5.1 ± 0.3, which keeps this object within the realm of the dwarf galaxies. A comparison with other RR Lyrae stars in ultra-faint systems indicates similar pulsational properties among them, which are different to those found among halo field stars and those in the largest of the Milky Way satellites. We also report the discovery of 31 additional short period variables in the field of view (RR Lyrae, SX Phe, eclipsing binaries, and a likely anomalous cepheid) which are likely not related with Hydra I

Kepler-503b: An Object at the Hydrogen Burning Mass Limit Orbiting a Subgiant Star

Using spectroscopic radial velocities with the APOGEE instrument and Gaia distance estimates, we demonstrate that Kepler-503b, currently considered a validated Kepler planet, is in fact a brown-dwarf/low-mass star in a nearly circular 7.2-day orbit around a subgiant star. Using a mass estimate for the primary star derived from stellar models, we derive a companion mass and radius of $0.075\pm0.003 \ M_{\odot}$ ($78.6\pm3.1 \ M_{Jup}$) and $0.099^{+0.006}_{-0.004}\ R_{\odot}$ ($0.96^{+0.06}_{-0.04}\ R_{Jup}$), respectively. Assuming the system is coeval, the evolutionary state of the primary indicates the age is $\sim6.7$ Gyr. Kepler-503b sits right at the hydrogen burning mass limit, straddling the boundary between brown dwarfs and very low-mass stars. More precise radial velocities and secondary eclipse spectroscopy with James Webb Space Telescope will provide improved measurements of the physical parameters and age of this important system to better constrain and understand the physics of these objects and their spectra. This system emphasizes the value of radial velocity observations to distinguish a genuine planet from astrophysical false positives, and is the first result from the SDSS-IV monitoring of Kepler planet candidates with the multi-object APOGEE instrument.Comment: Accepted for publication in ApJL, 12 pages, 3 figures, 2 table

Very Metal-poor Stars in the Outer Galactic Bulge Found by the Apogee Survey

Despite its importance for understanding the nature of early stellar generations and for constraining Galactic bulge formation models, at present little is known about the metal-poor stellar content of the central Milky Way. This is a consequence of the great distances involved and intervening dust obscuration, which challenge optical studies. However, the Apache Point Observatory Galactic Evolution Experiment (APOGEE), a wide-area, multifiber, high-resolution spectroscopic survey within Sloan Digital Sky Survey III (SDSS-III), is exploring the chemistry of all Galactic stellar populations at infrared wavelengths, with particular emphasis on the disk and the bulge. An automated spectral analysis of data on 2,403 giant stars in twelve fields in the bulge obtained during APOGEE commissioning yielded five stars with low metallicity([Fe/H]$\le-1.7$), including two that are very metal-poor [Fe/H]$\sim-2.1$ by bulge standards. Luminosity-based distance estimates place the five stars within the outer bulge, where other 1,246 of the analyzed stars may reside. A manual reanalysis of the spectra verifies the low metallicities, and finds these stars to be enhanced in the $\alpha$-elements O, Mg, and Si without significant $\alpha$-pattern differences with other local halo or metal-weak thick-disk stars of similar metallicity, or even with other more metal-rich bulge stars. While neither the kinematics nor chemistry of these stars can yet definitively determine which, if any, are truly bulge members, rather than denizens of other populations co-located with the bulge, the newly-identified stars reveal that the chemistry of metal-poor stars in the central Galaxy resembles that of metal-weak thick-disk stars at similar metallicity.Comment: 6 pages, 3 figures, 2 table

Discovery of a Dynamical Cold Point in the Heart of the Sagittarius dSph Galaxy with Observations from the APOGEE Project

The dynamics of the core of the Sagittarius (Sgr) dwarf spheroidal (dSph) galaxy are explored using high-resolution (R~22,500), H-band, near-infrared spectra of over 1,000 giant stars in the central 3 deg^2 of the system, of which 328 are identified as Sgr members. These data, among some of the earliest observations from the SDSS-III/Apache Point Observatory Galactic Evolution Experiment (APOGEE) and the largest published sample of high resolution Sgr dSph spectra to date, reveal a distinct gradient in the velocity dispersion of Sgr from 11-14 km/s for radii >0.8 degrees from center to a dynamical cold point of 8 km/s in the Sgr center --- a trend differing from that found in previous kinematical analyses of Sgr over larger scales that suggest a more or less flat dispersion profile at these radii. Well-fitting mass models with either cored and cusped dark matter distributions can be found to match the kinematical results, although the cored profile succeeds with significantly more isotropic stellar orbits than required for a cusped profile. It is unlikely that the cold point reflects an unusual mass distribution. The dispersion gradient may arise from variations in the mixture of populations with distinct kinematics within the dSph; this explanation is suggested (e.g., by detection of a metallicity gradient across similar radii), but not confirmed, by the present data. Despite these remaining uncertainties about their interpretation, these early test data (including some from instrument commissioning) demonstrate APOGEE's usefulness for precision dynamical studies, even for fields observed at extreme airmasses.Comment: 15 pages, 3 figure

The Apache Point Observatory Galactic Evolution Experiment: First Detection of High Velocity Milky Way Bar Stars

Commissioning observations with the Apache Point Observatory Galactic Evolution Experiment (APOGEE), part of the Sloan Digital Sky Survey III, have produced radial velocities (RVs) for ~4700 K/M-giant stars in the Milky Way bulge. These high-resolution (R \sim 22,500), high-S/N (>100 per resolution element), near-infrared (1.51-1.70 um; NIR) spectra provide accurate RVs (epsilon_v~0.2 km/s) for the sample of stars in 18 Galactic bulge fields spanning -1-32 deg. This represents the largest NIR high-resolution spectroscopic sample of giant stars ever assembled in this region of the Galaxy. A cold (sigma_v~30 km/s), high-velocity peak (V_GSR \sim +200 km/s) is found to comprise a significant fraction (~10%) of stars in many of these fields. These high RVs have not been detected in previous MW surveys and are not expected for a simple, circularly rotating disk. Preliminary distance estimates rule out an origin from the background Sagittarius tidal stream or a new stream in the MW disk. Comparison to various Galactic models suggests that these high RVs are best explained by stars in orbits of the Galactic bar potential, although some observational features remain unexplained.Comment: 7 pages, 4 figures, accepted for publication in ApJ Letter