Kepler-18b,c, and d: A System of Three Planets Confirmed by Transit Timing Variations, Light Curve Validation, Warm-Spitzer Photometry, and Radial Velocity Measurements

We report the detection of three transiting planets around a Sun-like star, which we designate Kepler-18. The transit signals were detected in photometric data from the Kepler satellite, and were confirmed to arise from planets using a combination of large transit-timing variations (TTVs), radial velocity variations, Warm-Spitzer observations, and statistical analysis of false-positive probabilities. The Kepler-18 star has a mass of 0.97 M_☉, a radius of 1.1 R_☉, an effective temperature of 5345 K, and an iron abundance of [Fe/H] = +0.19. The planets have orbital periods of approximately 3.5, 7.6, and 14.9 days. The innermost planet "b" is a "super-Earth" with a mass of 6.9 ± 3.4 M_⊕, a radius of 2.00 ± 0.10 R_⊕, and a mean density of 4.9 ± 2.4 g cm^3. The two outer planets "c" and "d" are both low-density Neptune-mass planets. Kepler-18c has a mass of 17.3 ± 1.9 M_⊕, a radius of 5.49 ± 0.26 R_⊕, and a mean density of 0.59 ± 0.07 g cm^3, while Kepler-18d has a mass of 16.4 ± 1.4 M_⊕, a radius of 6.98 ± 0.33 R_⊕ and a mean density of 0.27 ± 0.03 g cm^3. Kepler-18c and Kepler-18d have orbital periods near a 2:1 mean-motion resonance, leading to large and readily detected TTVs

NGC 7789: An Open Cluster Case Study

We have obtained high-resolution spectra of 32 giants in the open cluster NGC 7789 using the Wisconsin-Indiana-Yale-NOAO Hydra spectrograph. We explore differences in atmospheric parameters and elemental abundances caused by the use of the linelist developed for the Gaia-ESO Survey (GES) compared to one based on Arcturus used in our previous work. [Fe/H] values decrease when using the GES linelist instead of the Arcturus-based linelist; these differences are probably driven by systematically lower (~ -0.1 dex) GES surface gravities. Using the GES linelist we determine abundances for 10 elements - Fe, Mg, Si, Ca, Ti, Na, Ni, Zr, Ba, and La. We find the cluster's average metallicity [Fe/H] = 0.03 +/- 0.07 dex, in good agreement with literature values, and a lower [Mg/Fe] abundance than has been reported before for this cluster (0.11 +/- 0.05 dex). We also find the neutron-capture element barium to be highly enhanced - [Ba/Fe] = +0.48 +/- 0.08 - and disparate from cluster measurements of neutron-capture elements La and Zr (-0.08 +/- 0.05 and 0.08 +/- 0.08, respectively). This is in accordance with recent discoveries of supersolar Ba enhancement in young clusters along with more modest enhancement of other neutron-capture elements formed in similar environments.Comment: 15 pages, 9 figures, Table 1 typo fixe

Teachers, Tasks, and Tensions: Lessons From a Research-Practice Partnership

How teachers make sense of new academic standards significantly shapes the implementation of those standards. Professional development organized around the analysis of mathematical tasks has potential to prepare teachers for standards implementation by helping them develop common understandings of standards and how to help students meet ambitious new learning goals. In practice, however, designers and participants bring different goals to the professional development context, which becomes evident when teachers engage in task analysis. In this article, we use the design tensions framework (Tatar, 2007) to analyze these tensions within a research-practice partnership comprised of five university researchers, three district curriculum leaders from a large urban school district, 12 high school Algebra 1 teachers from nine schools in the district, and a small team of Web engineers. Primary data for the study consist of participant observation and field notes of meetings in which project stakeholders negotiated the design of the professional development, as well as interview and survey data. An analysis based on the design tensions framework helped our partnership surface, both in the moment and retrospectively, the need for designers of professional development focused on standards implementation to be adaptive and willing to evolve activities to satisfy multiple stakeholders\u27 goals for participation

Population-Specific Vital Rate Contributions Influence Management of an Endangered Ungulate

To develop effective management strategies for the recovery of threatened and endangered species, it is critical to identify those vital rates (survival and reproductive parameters) responsible for poor population performance and those whose increase will most efficiently change a population\u27s trajectory. In actual application, however, approaches identifying key vital rates are often limited by inadequate demographic data, by unrealistic assumptions of asymptotic population dynamics, and of equal, infinitesimal changes in mean vital rates. We evaluated the consequences of these limitations in an analysis of vital rates most important in the dynamics of federally endangered Sierra Nevada bighorn sheep (Ovis canadensis sierrae). Based on data collected from 1980 to 2007, we estimated vital rates in three isolated populations, accounting for sampling error, variance, and covariance. We used analytical sensitivity analysis, life-stage simulation analysis, and a novel non-asymptotic simulation approach to (1) identify vital rates that should be targeted for subspecies recovery; (2) assess vital rate patterns of endangered bighorn sheep relative to other ungulate populations; (3) evaluate the performance of asymptotic vs. non-asymptotic models for meeting short-term management objectives; and (4) simulate management scenarios for boosting bighorn sheep population growth rates. We found wide spatial and temporal variation in bighorn sheep vital rates, causing rates to vary in their importance to different populations. As a result, Sierra Nevada bighorn sheep exhibited population-specific dynamics that did not follow theoretical expectations or those observed in other ungulates. Our study suggests that vital rate inferences from large, increasing, or healthy populations may not be applicable to those that are small, declining, or endangered. We also found that, while asymptotic approaches were generally applicable to bighorn sheep conservation planning, our non-asymptotic population models yielded unexpected results of importance to managers. Finally, extreme differences in the dynamics of individual bighorn sheep populations imply that effective management strategies for endangered species recovery may often need to be population-specific

Avocado and Flaxseed Oleogels: the prospect of a healthy saturated fat substitute

Oleogelation is a novel technique that represents the forming of liquid oils into a gel-like structure by entrapping the liquid phase into a thermo-reversible and three-dimensional gel network. There has been a great interest in Oleogelation in many areas like pharmaceutics, food, and cosmetics. Oleogels are used to reduce the saturated and trans fatty acids in foods, making them healthier. The consumption of saturated and trans fatty acids increases the risk of cardiovascular diseases (Pehlivanoglu, Demirci, Toker, 2017). Avocado oil is high in oleic monounsaturated fatty acids and substantial amounts of health beneficial phytochemicals, such as vitamins and phytosterols. Avocado oil is rich in omega fatty acids that are good for human health, especially in preventing cardiovascular diseases (Wang et al., 2018). Safflower oil (SFO) from the seeds of Carthamus tinctorius L (Yenice variety) is colorless and flavorless and rich in linoleic acid (about 76% of total fat, a polyunsaturated FA) (He M, Armentano LE. 2011). Waxes are the most efficient oleogelators because of their ability to start crystallization at lower concentrations, easy to find, and they are natural. According to the FDA, waxes have been proven to be a good oleogelator, are natural, and have been recognized to have GRAS (generally recognized as safe) status (FDA,2018). Many types of oils and waxes can be used. For a successful oleogel, it is essential to find the right oil binding capacity (Patel et al., 2014). Three types of waxes were utilized; rice bran wax (4 and 8%), and carnauba, and candelilla wax (3 and 6%). The wax can affect the taste and texture of the food. It is essential to find the right ratio of wax to oil because a higher amount of wax will result in a strong and brittle gel. Otherwise, a small amount of wax will not create a stable gel. The objective of this study was to find the minimum amount of waxes to add in avocado oil and flaxseed oil to produce a stable oleogels useful for the food industry. The stability of the oleogel was analyzed with Oil Binding Capacity (OBC) Method and the visualization method at two different conditions (room temperature and 35 ºC) during two different times (Day 1 and Day 7). The fatty acid composition of the oils was evaluated by gas chromatography (Florence et al., 2012). Candelilla wax has the most significant oil binding capacity, and it is also the most stable, even at higher temperatures. Carnauba wax is slightly stable but only with 8% wax. Rice bran wax was not stable at all with 3% wax at room and oven temperature. It had the lowest oil binding capacity out of all three waxes. Higher amounts of wax improve the oil binding capacity

Magnetic field dependence of the internal quality factor and noise performance of lumped-element kinetic inductance detectors

We present a technique for increasing the internal quality factor of kinetic inductance detectors (KIDs) by nulling ambient magnetic fields with a properly applied magnetic field. The KIDs used in this study are made from thin-film aluminum, they are mounted inside a light-tight package made from bulk aluminum, and they are operated near $150 \, \mathrm{mK}$. Since the thin-film aluminum has a slightly elevated critical temperature ($T_\mathrm{c} = 1.4 \, \mathrm{K}$), it therefore transitions before the package ($T_\mathrm{c} = 1.2 \, \mathrm{K}$), which also serves as a magnetic shield. On cooldown, ambient magnetic fields as small as approximately $30 \, \mathrm{\mu T}$ can produce vortices in the thin-film aluminum as it transitions because the bulk aluminum package has not yet transitioned and therefore is not yet shielding. These vortices become trapped inside the aluminum package below $1.2 \, \mathrm{K}$ and ultimately produce low internal quality factors in the thin-film superconducting resonators. We show that by controlling the strength of the magnetic field present when the thin film transitions, we can control the internal quality factor of the resonators. We also compare the noise performance with and without vortices present, and find no evidence for excess noise beyond the increase in amplifier noise, which is expected with increasing loss.Comment: 5 pages, 4 figure

Friends of Hot Jupiters II: No Correspondence Between Hot-Jupiter Spin-Orbit Misalignment and the Incidence of Directly Imaged Stellar Companions

Multi-star systems are common, yet little is known about a stellar companion's influence on the formation and evolution of planetary systems. For instance, stellar companions may have facilitated the inward migration of hot Jupiters towards to their present day positions. Many observed short period gas giant planets also have orbits that are misaligned with respect to their star's spin axis, which has also been attributed to the presence of a massive outer companion on a non-coplanar orbit. We present the results of a multi-band direct imaging survey using Keck NIRC2 to measure the fraction of short period gas giant planets found in multi-star systems. Over three years, we completed a survey of 50 targets ("Friends of Hot Jupiters") with 27 targets showing some signature of multi-body interaction (misaligned or eccentric orbits) and 23 targets in a control sample (well-aligned and circular orbits). We report the masses, projected separations, and confirmed common proper motion for the 19 stellar companions found around 17 stars. Correcting for survey incompleteness, we report companion fractions of $48\%\pm9\%$, $47\%\pm12\%$, and $51\%\pm13\%$ in our total, misaligned/eccentric, and control samples, respectively. This total stellar companion fraction is $2.8\,\sigma$ larger than the fraction of field stars with companions approximately $50-2000\,$AU. We observe no correlation between misaligned/eccentric hot Jupiter systems and the incidence of stellar companions. Combining this result with our previous radial velocity survey, we determine that $72\% \pm 16\%$ of hot Jupiters are part of multi-planet and/or multi-star systems.Comment: typos and references updated; 25 pages, 7 figures and 10 tables, accepted for publication in Ap

Ground- and Space-based Detection of the Thermal Emission Spectrum of the Transiting Hot Jupiter KELT-2Ab

We describe the detection of water vapor in the atmosphere of the transiting hot Jupiter KELT-2Ab by treating the star-planet system as a spectroscopic binary with high-resolution, ground-based spectroscopy. We resolve the signal of the planet's motion with deep combined flux observations of the star and the planet. In total, six epochs of Keck NIRSPEC $L$-band observations were obtained, and the full data set was subjected to a cross correlation analysis with a grid of self-consistent atmospheric models. We measure a radial projection of the Keplerian velocity, $K_P$, of 148 $\pm$ 7 km s$^{-1}$, consistent with transit measurements, and detect water vapor at 3.8$\sigma$. We combine NIRSPEC $L$-band data with $Spitzer$ IRAC secondary eclipse data to further probe the metallicity and carbon-to-oxygen ratio of KELT-2Ab's atmosphere. While the NIRSPEC analysis provides few extra constraints on the $Spitzer$ data, it does provide roughly the same constraints on metallicity and carbon-to-oxygen ratio. This bodes well for future investigations of the atmospheres of non-transiting hot Jupiters.Comment: accepted to A