786 research outputs found
Professional Development Needs for Educators Working with Children with Autism Spectrum Disorders in Inclusive School Environments
The primary objective of this mixed methods study was to identify educators’ professional development needs to determine how best to support them in providing quality programming for children with Autism Spectrum Disorders (ASD) within an inclusive educational system. Information was collected through focus groups with key school board informants (n = 33) and a survey of educators (n = 225). The results indicate that educators have found it difficult to meet the wide-ranging and varying needs of children with ASD within a strictly defined model of inclusive education. Educators consistently emphasized the need for multileveled and multipronged professional development that is accessible in a timely fashion and available as needs arise. The need for educational programs that work for children with ASD being taught within inclusive education settings is highlighted
Measuring Transit Signal Recovery in the Kepler Pipeline. III. Completeness of the Q1-Q17 DR24 Planet Candidate Catalogue, with Important Caveats for Occurrence Rate Calculations
With each new version of the Kepler pipeline and resulting planet candidate
catalogue, an updated measurement of the underlying planet population can only
be recovered with an corresponding measurement of the Kepler pipeline detection
efficiency. Here, we present measurements of the sensitivity of the pipeline
(version 9.2) used to generate the Q1-Q17 DR24 planet candidate catalog
(Coughlin et al. 2016). We measure this by injecting simulated transiting
planets into the pixel-level data of 159,013 targets across the entire Kepler
focal plane, and examining the recovery rate. Unlike previous versions of the
Kepler pipeline, we find a strong period dependence in the measured detection
efficiency, with longer (>40 day) periods having a significantly lower
detectability than shorter periods, introduced in part by an incorrectly
implemented veto. Consequently, the sensitivity of the 9.2 pipeline cannot be
cast as a simple one-dimensional function of the signal strength of the
candidate planet signal as was possible for previous versions of the pipeline.
We report on the implications for occurrence rate calculations based on the
Q1-Q17 DR24 planet candidate catalog and offer important caveats and
recommendations for performing such calculations. As before, we make available
the entire table of injected planet parameters and whether they were recovered
by the pipeline, enabling readers to derive the pipeline detection sensitivity
in the planet and/or stellar parameter space of their choice.Comment: 8 pages, 5 figures, full electronic version of Table 1 available at
the NASA Exoplanet Archive; accepted by ApJ May 2nd, 201
Sensitivity Analyses of Exoplanet Occurrence Rates from Kepler and Gaia
We infer the number of planets per star as a function of orbital period and planet size using Kepler archival data products with updated stellar properties from the Gaia Data Release 2. Using hierarchical Bayesian modeling and Hamiltonian Monte Carlo, we incorporate planet radius uncertainties into an inhomogeneous Poisson point process model. We demonstrate that this model captures the general features of the outcome of the planet formation and evolution around GK stars and provides an infrastructure to use the Kepler results to constrain analytic planet distribution models. We report an increased mean and variance in the marginal posterior distributions for the number of planets per GK star when including planet radius measurement uncertainties. We estimate the number of planets per GK star between 0.75 and 2.5 R⊕ and with orbital periods of 50–300 days to have a 68% credible interval of 0.49–0.77 and a posterior mean of 0.63. This posterior has a smaller mean and a larger variance than the occurrence rate calculated in this work and in Burke et al. for the same parameter space using the Q1−Q16 (previous Kepler planet candidate and stellar catalog). We attribute the smaller mean to many of the instrumental false positives at longer orbital periods being removed from the DR25 catalog. We find that the accuracy and precision of our hierarchical Bayesian model posterior distributions are less sensitive to the total number of planets in the sample, and more so for the characteristics of the catalog completeness and reliability and the span of the planet parameter space
Terrestrial Planet Occurrence Rates for the Kepler GK Dwarf Sample
We measure planet occurrence rates using the planet candidates discovered by
the Q1-Q16 Kepler pipeline search. This study examines planet occurrence rates
for the Kepler GK dwarf target sample for planet radii, 0.75<Rp<2.5 Rearth, and
orbital periods, 50<Porb<300 days, with an emphasis on a thorough exploration
and identification of the most important sources of systematic uncertainties.
Integrating over this parameter space, we measure an occurrence rate of F=0.77
planets per star, with an allowed range of 0.3<F<1.9. The allowed range takes
into account both statistical and systematic uncertainties, and values of F
beyond the allowed range are significantly in disagreement with our analysis.
We generally find higher planet occurrence rates and a steeper increase in
planet occurrence rates towards small planets than previous studies of the
Kepler GK dwarf sample. Through extrapolation, we find that the one year
orbital period terrestrial planet occurrence rate, zeta_1=0.1, with an allowed
range of 0.01<zeta_1<2, where zeta_1 is defined as the number of planets per
star within 20% of the Rp and Porb of Earth. For G dwarf hosts, the zeta_1
parameter space is a subset of the larger eta_earth parameter space, thus
zeta_1 places a lower limit on eta_earth for G dwarf hosts. From our analysis,
we identify the leading sources of systematics impacting Kepler occurrence rate
determinations as: reliability of the planet candidate sample, planet radii,
pipeline completeness, and stellar parameters.Comment: 19 Pages, 17 Figures, Submitted ApJ. Python source to support Kepler
pipeline completeness estimates available at
http://github.com/christopherburke/KeplerPORTs
A Habitable-zone Earth-sized Planet Rescued from False Positive Status
We report the discovery of an Earth-sized planet in the habitable zone of a
low-mass star called Kepler-1649. The planet, Kepler-1649 c, is
1.06 times the size of Earth and transits its 0.1977 +/-
0.0051 Msun mid M-dwarf host star every 19.5 days. It receives 74 +/- 3 % the
incident flux of Earth, giving it an equilibrium temperature of 234 +/- 20K and
placing it firmly inside the circumstellar habitable zone. Kepler-1649 also
hosts a previously-known inner planet that orbits every 8.7 days and is roughly
equivalent to Venus in size and incident flux. Kepler-1649 c was originally
classified as a false positive by the Kepler pipeline, but was rescued as part
of a systematic visual inspection of all automatically dispositioned Kepler
false positives. This discovery highlights the value of human inspection of
planet candidates even as automated techniques improve, and hints that
terrestrial planets around mid to late M-dwarfs may be more common than those
around more massive stars.Comment: 11 pages, 3 figures, 1 table. Accepted for publication in ApJ
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