1,702 research outputs found

    Obliquities of Kepler Stars: Comparison of Single- and Multiple-Transit Systems

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    The stellar obliquity of a transiting planetary system can be constrained by combining measurements of the star's rotation period, radius, and projected rotational velocity. Here we present a hierarchical Bayesian technique for recovering the obliquity distribution of a population of transiting planetary systems, and apply it to a sample of 70 Kepler Objects of Interest. With ~95% confidence we find that the obliquities of stars with only a single detected transiting planet are systematically larger than those with multiple detected transiting planets. This suggests that a substantial fraction of Kepler's single-transiting systems represent dynamically hotter, less orderly systems than the "pancake-flat" multiple-transiting systems.Comment: 8 pages, 7 figures, accepted to Ap

    Epidural Analgesia Decreases Narcotic Requirements in Low Level Spina Bifida Patients Undergoing Urologic Laparotomy for Neurogenic Bladder and Bowel

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    Purpose Concern of anatomical anomalies and worsening neurologic symptoms has prevented widespread use of epidural catheters in patients with low level spina bifida (LLSB). We hypothesize that thoracic epidural placement in the T9-T10 interspace is safe and decreases narcotic requirements in LLSB patients following major open lower urinary tract reconstruction (LUTR). Materials and Methods We reviewed consecutive LLSB patients who had LUTR and epidurals for post-operative pain control. Controls were LLSB patients who received single shot transversus abdominis plane (TAP) blocks with similar procedures. Complications from epidural placement, including changes in motor and sensory status were recorded. Opioid consumption was calculated utilizing equivalent IV morphine doses. Mean and maximum pain scores on post-operative day (POD) 0-3 were calculated. Results 10 LLSB patients who had lower urinary tract reconstruction and epidurals were matched to 10 LLSB patients who had lower urinary tract reconstruction and transverse abdominis plane blocks. Groups were demographically similar. All had full abdominal sensation and functional levels at or below L3. No epidural complications or changes in neurological status were noted. The epidural group had decreased opioid consumption on POD 0-3 (0.75 mg/kg vs. 1.29 mg/kg, p=0.04). Pain scores were similar or improved in the epidural group. Conclusions Thoracic epidural analgesia appears to be a safe and effective opioid sparing option to assist with post-operative pain management following lower urinary tract reconstruction in LLSB patients

    The California-Kepler Survey. IV. Metal-rich Stars Host a Greater Diversity of Planets

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    Probing the connection between a star's metallicity and the presence and properties of any associated planets offers an observational link between conditions during the epoch of planet formation and mature planetary systems. We explore this connection by analyzing the metallicities of Kepler target stars and the subset of stars found to host transiting planets. After correcting for survey incompleteness, we measure planet occurrence: the number of planets per 100 stars with a given metallicity MM. Planet occurrence correlates with metallicity for some, but not all, planet sizes and orbital periods. For warm super-Earths having P=10100P = 10-100 days and RP=1.01.7 RER_P = 1.0-1.7~R_E, planet occurrence is nearly constant over metallicities spanning -0.4 dex to +0.4 dex. We find 20 warm super-Earths per 100 stars, regardless of metallicity. In contrast, the occurrence of warm sub-Neptunes (RP=1.74.0 RER_P = 1.7-4.0~R_E) doubles over that same metallicity interval, from 20 to 40 planets per 100 stars. We model the distribution of planets as df10βMdMd f \propto 10^{\beta M} d M, where β\beta characterizes the strength of any metallicity correlation. This correlation steepens with decreasing orbital period and increasing planet size. For warm super-Earths β=0.30.2+0.2\beta = -0.3^{+0.2}_{-0.2}, while for hot Jupiters β=+3.40.8+0.9\beta = +3.4^{+0.9}_{-0.8}. High metallicities in protoplanetary disks may increase the mass of the largest rocky cores or the speed at which they are assembled, enhancing the production of planets larger than 1.7 RER_E. The association between high metallicity and short-period planets may reflect disk density profiles that facilitate the inward migration of solids or higher rates of planet-planet scattering.Comment: 32 pages, 15 figures, 9 tables, accepted for publication in The Astronomical Journa

    Orbital Orientations of Exoplanets: HAT-P-4b is Prograde and HAT-14b is Retrograde

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    We present observations of the Rossiter-McLaughlin effect for two exoplanetary systems, revealing the orientations of their orbits relative to the rotation axes of their parent stars. HAT-P-4b is prograde, with a sky-projected spin-orbit angle of λ = –4.9 ± 11.9 deg. In contrast, HAT-P-14b is retrograde, with λ = 189.1 ± 5.1 deg. These results conform with a previously noted pattern among the stellar hosts of close-in giant planets: hotter stars have a wide range of obliquities and cooler stars have low obliquities. This, in turn, suggests that three-body dynamics and tidal dissipation are responsible for the short-period orbits of many exoplanets. In addition, our data revealed a third body in the HAT-P-4 system, which could be a second planet or a companion star

    The California-Kepler Survey. II. Precise Physical Properties of 2025 Kepler Planets and Their Host Stars

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    We present stellar and planetary properties for 1305 Kepler Objects of Interest (KOIs) hosting 2025 planet candidates observed as part of the California-Kepler Survey. We combine spectroscopic constraints, presented in Paper I, with stellar interior modeling to estimate stellar masses, radii, and ages. Stellar radii are typically constrained to 11%, compared to 40% when only photometric constraints are used. Stellar masses are constrained to 4%, and ages are constrained to 30%. We verify the integrity of the stellar parameters through comparisons with asteroseismic studies and Gaia parallaxes. We also recompute planetary radii for 2025 planet candidates. Because knowledge of planetary radii is often limited by uncertainties in stellar size, we improve the uncertainties in planet radii from typically 42% to 12%. We also leverage improved knowledge of stellar effective temperature to recompute incident stellar fluxes for the planets, now precise to 21%, compared to a factor of two when derived from photometry.Comment: 13 pages, 4 figures, 4 tables, accepted for publication in AJ; full versions of tables 3 and 4 are include

    Constraints on the Obliquities of Kepler Planet-Hosting Stars

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    Stars with hot Jupiters have obliquities ranging from 0-180 degrees, but relatively little is known about the obliquities of stars with smaller planets. Using data from the California-Kepler Survey, we investigate the obliquities of stars with planets spanning a wide range of sizes, most of which are smaller than Neptune. First, we identify 156 planet hosts for which measurements of the projected rotation velocity (vsini) and rotation period are both available. By combining estimates of v and vsini, we find nearly all the stars to be compatible with high inclination, and hence, low obliquity (less than about 20 degrees). Second, we focus on a sample of 159 hot stars (> 6000K) for which vsini is available but not necessarily the rotation period. We find 6 stars for which vsini is anomalously low, an indicator of high obliquity. Half of these have hot Jupiters, even though only 3% of the stars that were searched have hot Jupiters. We also compare the vsini distribution of the hot stars with planets to that of 83 control stars selected without prior knowledge of planets. The mean vsini of the control stars is lower than that of the planet hosts by a factor of approximately pi/4, as one would expect if the planet hosts have low obliquities. All these findings suggest that the Kepler planet-hosting stars generally have low obliquities, with the exception of hot stars with hot Jupiters.Comment: AJ, in pres

    Methods and Motivations of Multigenerational Churches In Selecting a Worship Music Identity

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    Churches in the twenty-first century come in all types, shapes, and sizes. The church plant movement is bringing many new churches into existence. With many of these church plants, the assumption is that a contemporary worship style comes with it. This could be viewed this way, because of the high population of younger people that attend these churches. Churches like Elevation Church, North Point Church, Passion City Church, and Saddleback Community Church are all church plants. These churches are magnets for newly established Christians and those seeking to answer questions about God for the first time. They are magnets for individuals who have been “dechurched.” Caleb Davis, from acts29.com defines dechurched as “They were once part of the church but now are not…” These church plants attract very specific types of people. These individuals are typically seeking something that looks very different from what they have traditionally viewed as church. Thus, they choose the new, contemporary church plant model. But what about the thousands of churches born in the 1900s or before? What about churches that have more than just one or two generations attending? These churches have people of all ages. Some have families with multiple generations living and dying within that church. What does worship look like for these churches? What happens when worship music styles shift? How do their leaders navigate these waters? This thesis will seek to answer the question, How do churches that are multigenerational find their worship music identity

    The California-Kepler Survey V. Peas in a Pod: Planets in a Kepler Multi-planet System are Similar in Size and Regularly Spaced

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    We have established precise planet radii, semimajor axes, incident stellar fluxes, and stellar masses for 909 planets in 355 multi-planet systems discovered by Kepler. In this sample, we find that planets within a single multi-planet system have correlated sizes: each planet is more likely to be the size of its neighbor than a size drawn at random from the distribution of observed planet sizes. In systems with three or more planets, the planets tend to have a regular spacing: the orbital period ratios of adjacent pairs of planets are correlated. Furthermore, the orbital period ratios are smaller in systems with smaller planets, suggesting that the patterns in planet sizes and spacing are linked through formation and/or subsequent orbital dynamics. Yet, we find that essentially no planets have orbital period ratios smaller than 1.21.2, regardless of planet size. Using empirical mass-radius relationships, we estimate the mutual Hill separations of planet pairs. We find that 93%93\% of the planet pairs are at least 10 mutual Hill radii apart, and that a spacing of 20\sim20 mutual Hill radii is most common. We also find that when comparing planet sizes, the outer planet is larger in 65±0.4%65 \pm 0.4\% of cases, and the typical ratio of the outer to inner planet size is positively correlated with the temperature difference between the planets. This could be the result of photo-evaporation.Comment: Published in The Astronomical Journal. 15 pages, 17 figure

    Alternate Phrase Suggestions from Voice Input

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    Techniques to improve the process of correcting text transcription of a voice input are described. Words or phrases of the voice input that are not recognized with sufficient confidence are identified and displayed in a manner that distinguishes such phrases from the rest of the transcribed text. Alternatives for the low confidence terms are determined and displayed as suggestions. The user can view and select one or more of the alternative suggestions to replace the low confidence terms
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