Carbon and Oxygen Isotopic Ratios. II. Semiregular Variable M Giants

Carbon and oxygen isotopic ratios are reported for a sample of 51 SRb- and Lb-type variable asymptotic giant branch stars. Vibration-rotation first- and second-overtone CO lines in 1.5-2.5 mum spectra were measured to derive isotopic ratios for 12C/13C, 16O/17O, and 16O/18O. Comparisons with previous measurements for individual stars and with various samples of evolved stars, as available in the extant literature, are discussed. Using the oxygen isotopic ratios, the masses of the SRb stars can be derived. Combining the masses with Gaia luminosities, the SRb stars are shown to be antecedents of the Mira variables. The limiting parameters where plane-parallel, hydrostatic equilibrium model atmospheres can be used for abundance analysis of M giants are explored

Infrared High-Resolution Spectroscopy of Post-AGB Circumstellar Disks. I. HR 4049 - The Winnowing Flow Observed?

High-resolution infrared spectroscopy in the 2.3-4.6 micron region is reported for the peculiar A supergiant, single-lined spectroscopic binary HR 4049. Lines from the CO fundamental and first overtone, OH fundamental, and several H2O vibration-rotation transitions have been observed in the near-infrared spectrum. The spectrum of HR 4049 appears principally in emission through the 3 and 4.6 micron region and in absorption in the 2 micron region. The 4.6 micron spectrum shows a rich 'forest' of emission lines. All the spectral lines observed in the 2.3-4.6 micron spectrum are shown to be circumbinary in origin. The presence of OH and H2O lines confirm the oxygen-rich nature of the circumbinary gas which is in contrast to the previously detected carbon-rich material. The emission and absorption line profiles show that the circumbinary gas is located in a thin, rotating layer near the dust disk. The properties of the dust and gas circumbinary disk and the spectroscopic orbit yield masses for the individual stars, M_AI~0.58 Msolar and M_MV~0.34 Msolar. Gas in the disk also has an outward flow with a velocity of $\gtrsim$ 1 km/s. The severe depletion of refractory elements but near-solar abundances of volatile elements observed in HR 4049 results from abundance winnowing. The separation of the volatiles from the grains in the disk and the subsequent accretion by the star are discussed. Contrary to prior reports, the HR 4049 carbon and oxygen isotopic abundances are typical AGB values: 12C/13C=6^{+9}_{-4} and 16O/17O>200.Comment: 42 pages, 14 figures, Accepted by Ap

Adoption and Abandonment of Precision Soil Sampling in Cotton Production

Technology adoption in precision agriculture has received considerable attention, while abandonment has received little. Our objective was to identify factors motivating adoption and abandonment of precision soil sampling in cotton. Results indicate younger producers who farmed more cotton area, owned more of their cropland, planted more non-cotton area, used a computer, or used a Personal Digital Assistant (PDA) were more likely to adopt precision soil sampling. Those with more cotton area or who owned livestock were more likely to abandon, while those who used precision soil sampling longer, used a PDA, or used variable-rate fertilizer application were less likely to abandon.Crop Production/Industries,

Precision Agriculture Technology Adoption for Cotton Production

Many studies on the adoption of precision technologies have generally used logit models to explain the adoption behavior of individuals. This study investigates factors affecting the number of specific types of precision agriculture technologies adopted by cotton farmers. Particular attention is given to the influence of spatial yield variability on the number of precision farming technologies adopted, using a Count data estimation procedure and farm-level data. Results indicate that farmers with more within-field yield variability adopted a larger number of precision agriculture technologies. Younger and better educated producers and the number of precision agriculture technologies were significantly correlated. Finally, farmers using computers for management decisions also adopted a larger number of precision agriculture technologies.precision technologies, Poisson, Negative Binomial, count-data method, GIS, education, cotton, Agricultural and Food Policy, Farm Management, Labor and Human Capital, Land Economics/Use, Productivity Analysis, Resource /Energy Economics and Policy,

Intensity of Precision Agriculture Technology Adoption by Cotton Producers

Many studies on the adoption of precision technologies have generally used logit models to explain the adoption behavior of individuals. This study investigates factors affecting the intensity of precision agriculture technologies adopted by cotton farmers. Particular attention is given to the role of spatial yield variability on the number of precision farming technologies adopted, using a count data estimation procedure and farm-level data. Results indicate that farmers with more within-field yield variability adopted a higher number of precision agriculture technologies. Younger and better educated producers and the number of precision agriculture technologies used were significantly correlated. Finally, farmers using computers for management decisions also adopted a higher number of precision agriculture technologies.precision technologies, Poisson, negative binomial count data method, GPS, education, cotton, Crop Production/Industries, Farm Management, Production Economics, Research and Development/Tech Change/Emerging Technologies,

Fluorine Abundances in the Large Magellanic Cloud and Omega Centauri: Evidence for Neutrino Nucleosynthesis?

The behavior of fluorine with metallicity has not yet been probed in any stellar population. In this work, we present the first fluorine abundances measured outside of the Milky Way from a sample of red giants in the Large Magellanic Cloud (LMC), as well the Galactic globular cluster Omega Centauri. The fluorine abundances are derived from vibration-rotation transitions of HF using infrared spectra obtained with the Phoenix spectrograph on the Gemini South 8.1m telescope. It is found that the abundance ratio of F/O declines as the oxygen abundance decreases. The values of F/O are especially low in the two Omega Cen giants; this very low value of F/O probably indicates that 19F synthesis in asymptotic giant branch (AGB) stars is not the dominant source of fluorine in stellar populations. The observed decline in F/O with lower O abundances is in qualitative agreement with what is expected if 19F is produced via H- and He-burning sequences in very massive stars, with this fluorine then ejected in high mass-loss rate Wolf-Rayet winds. A quantitative comparison of observations with this process awaits results from more detailed chemical evolution models incorporating the yields from Wolf-Rayet winds. Perhaps of more significance is the quantitative agreement between the Galactic and LMC results with predictions from models in which 19F is produced from neutrino nucleosynthesis during core collpase in supernovae of Type II. The very low values of F/O in Omega Cen are also in agreement with neutrino nucleosynthesis models if the ``peculiar'' star formation history of Omega Cen, with 2-4 distinct episodes of star formation, is considered.Comment: 19 pages, 2 tables, 4 figures. In press to the Astronomical Journa

The Vehicle, 1963, Vol. 5

Vol. 5 Table of Contents Milepostspage 3 Rhyme Conceived At DawnDaun Alan Leggpage 4 NightRoss Kokospage 4 UncrownedOra Blanche T. Kingpage 4 SunfishingL.J.G.page 5 The Man Who Went To New YorkEric Crookspage 7 The DreamPauline B. Smithpage 18 Open WindowsDavid Helmpage 19 SalvationChristine McCollpage 19 The Chess GamePierre Hooverpage 20 CataclysmRaymond Kapraunpage 20 A Microscopic ViewKenneth L. Vadovskypage 21 See How Love ComesLiz Puckettpage 21 A Can Of Beer For AndyKenneth L. Vadovskypage 22 A MonsterDixie Lee Motleypage 28 InconstancyJanice Brookspage 29 DreamerDaun Alan Leggpage 29 The Third WishGlenda Vursellpage 30 The MiracleJanice Brookspage 32 What Lives Where Love Once Dwelt?Vernell Vyvialpage 33 The Most Unforgettable Person I Have Ever KnownJames Flingpage 34 Winter ThoughtsPauline B. Smithpage 35 A Winter NightPeggy Lambertpage 35 The Silver WhaleL.J.G.page 36 RaindropsDixie Lee Motleypage 40 Conflict Of Soul IJean Konzelmanpage 40 JudyChristine McCollpage 41 Sadness No. 3 (Vergessen)Sherry Sue Frypage 41 Lost GoldLarry Pricepage 42 EchoesCharles Cooleypage 48 TruthDaun Alan Leggpage 48 SunsetCarol Bennettpage 48 Cover designTom Windsor Illustration for winning storyJoel E. Hendrickshttps://thekeep.eiu.edu/vehicle/1011/thumbnail.jp

LSST: from Science Drivers to Reference Design and Anticipated Data Products

(Abridged) We describe here the most ambitious survey currently planned in the optical, the Large Synoptic Survey Telescope (LSST). A vast array of science will be enabled by a single wide-deep-fast sky survey, and LSST will have unique survey capability in the faint time domain. The LSST design is driven by four main science themes: probing dark energy and dark matter, taking an inventory of the Solar System, exploring the transient optical sky, and mapping the Milky Way. LSST will be a wide-field ground-based system sited at Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m effective) primary mirror, a 9.6 deg$^2$ field of view, and a 3.2 Gigapixel camera. The standard observing sequence will consist of pairs of 15-second exposures in a given field, with two such visits in each pointing in a given night. With these repeats, the LSST system is capable of imaging about 10,000 square degrees of sky in a single filter in three nights. The typical 5$\sigma$ point-source depth in a single visit in $r$ will be $\sim 24.5$ (AB). The project is in the construction phase and will begin regular survey operations by 2022. The survey area will be contained within 30,000 deg$^2$ with $\delta<+34.5^\circ$, and will be imaged multiple times in six bands, $ugrizy$, covering the wavelength range 320--1050 nm. About 90\% of the observing time will be devoted to a deep-wide-fast survey mode which will uniformly observe a 18,000 deg$^2$ region about 800 times (summed over all six bands) during the anticipated 10 years of operations, and yield a coadded map to $r\sim27.5$. The remaining 10\% of the observing time will be allocated to projects such as a Very Deep and Fast time domain survey. The goal is to make LSST data products, including a relational database of about 32 trillion observations of 40 billion objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures available from https://www.lsst.org/overvie

Employee stock options: much more valuable than you thought

Previous papers have argued that trading restrictions can result in a typical employee stock option having a subjective value (certainty equivalent value) that is substantially less than its Black-Scholes value. However, these analyses ignore the manager's ability to (at least partially) control the risk level within the firm. In this paper, we show how managerial control can lead to such options having much larger certainty equivalent values for employees who can exercise control. We also show that the potential for early exercise is substantially less valuable with managerial control. The certainty equivalent value for a European option with managerial control can easily exceed the Black-Scholes value for a comparable option without control. However, it is questionable whether Black-Scholes is an appropriate benchmark for an option where the underlying process exhibits controlled volatility. We show how to obtain a risk-neutral valuation for such an option. That risk-neutral value can be substantially greater or less than the Black- Scholes value. Furthermore, the option's certainty equivalent value can also be greater or less than its risk-neutral value