8,375 research outputs found

    MARVEL analysis of the measured high-resolution rovibronic spectra of the calcium monohydroxide radical (CaOH)

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    The calcium monohydroxide radical (CaOH) is an important astrophysical molecule relevant to cool stars and rocky exoplanets, amongst other astronomical environments. Here, we present a consistent set of highly accurate rovibronic (rotation-vibration-electronic) energy levels for the five lowest electronic states (\tilde{X}\,^2\Sigma^+, \tilde{A}\,^2\Pi, \tilde{B}\,^2\Sigma^+, \tilde{C}\,^2\Delta, \tilde{D}\,^2\Sigma^+) of CaOH. A comprehensive analysis of the published spectroscopic literature on this system has allowed 1955 energy levels to be determined from 3204 rovibronic experimental transitions, all with unique quantum number labelling and measurement uncertainties. The dataset covers rotational excitation up to J=62.5J=62.5 for molecular states below 29\,000~cm−1^{-1}. The analysis was performed using the MARVEL algorithm, which is a robust procedure based on the theory of spectroscopic networks. The dataset provided will significantly aid future interstellar, circumstellar and atmospheric detections of CaOH, as well as assisting in the design of efficient laser cooling schemes in ultracold molecule research and precision tests of fundamental physics

    Accurate Prediction of the Ammonia Probes of a Variable Proton-to-Electron Mass Ratio

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    A comprehensive study of the mass sensitivity of the vibration-rotation-inversion transitions of 14^{14}NH3_3, 15^{15}NH3_3, 14^{14}ND3_3, and 15^{15}ND3_3 is carried out variationally using the TROVE approach. Variational calculations are robust and accurate, offering a new way to compute sensitivity coefficients. Particular attention is paid to the Δk=±3\Delta k=\pm 3 transitions between the accidentally coinciding rotation-inversion energy levels of the ν2=0+,0−,1+\nu_2=0^+,0^-,1^+ and 1−1^- states, and the inversion transitions in the ν4=1\nu_4=1 state affected by the "giant" ll-type doubling effect. These transitions exhibit highly anomalous sensitivities, thus appearing as promising probes of a possible cosmological variation of the proton-to-electron mass ratio μ\mu. Moreover, a simultaneous comparison of the calculated sensitivities reveals a sizeable isotopic dependence which could aid an exclusive ammonia detection.Comment: 18 pages, 2 figures, 10 table

    Acer saccharinum L.

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    https://thekeep.eiu.edu/herbarium_specimens_byname/11945/thumbnail.jp

    Estimating Alfalfa Quality in the Field

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    Knowledge of alfalfa nutritive value is essential for making informed forage management decisions in alfalfa-based livestock production systems. However, most harvest management and storage decisions are made with no chemical composition information because obtaining analytical data is time consuming and expensive. The quality of forage needed for a particular operation is influenced by the intended use of the forage and by the dietary requirements of a given class of livestock. The detergent fiber system of forage analysis (neutral detergent fiber, NDF; and acid detergent fiber, ADF) coupled with a measure of crude protein (CP) provide vital information for balancing rations of lactating dairy cows (Van Soest, 1994; Mertens, 1983). Therefore, knowledge of the preharvest concentration of NDF, ADF, and CP in alfalfa would allow producers to harvest, store, and inventory this feed resource based on its potential value in a ration

    The Price Premium for Organic Babyfood: A Hedonic Analysis

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    The price premium associated with organic babyfood is estimated by applying a hedonic model to price and characteristic data for babyfood products collected in two cities: Raleigh, North Carolina, and San Jose, California. The price per ounce of babyfood is modeled as a function of a number of babyfood and store characteristics. The estimated organic price premium is generally equal to 3 cents to 4 cents per ounce. To the extent this premium reflects consumer willingness to pay to reduce pesticide exposures, it could be used to infer values for reduced dietary exposures to pesticide residues for babies.babyfood, hedonic analysis, organic foods, Demand and Price Analysis,
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