9,868 research outputs found

    A Chemical Composition Survey of the Iron-Complex Globular Cluster NGC 6273 (M 19)

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    Recent observations have shown that a growing number of the most massive Galactic globular clusters contain multiple populations of stars with different [Fe/H] and neutron-capture element abundances. NGC 6273 has only recently been recognized as a member of this "iron-complex" cluster class, and we provide here a chemical and kinematic analysis of > 300 red giant branch (RGB) and asymptotic giant branch (AGB) member stars using high resolution spectra obtained with the Magellan-M2FS and VLT-FLAMES instruments. Multiple lines of evidence indicate that NGC 6273 possesses an intrinsic metallicity spread that ranges from about [Fe/H] = -2 to -1 dex, and may include at least three populations with different [Fe/H] values. The three populations identified here contain separate first (Na/Al-poor) and second (Na/Al-rich) generation stars, but a Mg-Al anti-correlation may only be present in stars with [Fe/H] > -1.65. The strong correlation between [La/Eu] and [Fe/H] suggests that the s-process must have dominated the heavy element enrichment at higher metallicities. A small group of stars with low [alpha/Fe] is identified and may have been accreted from a former surrounding field star population. The cluster's large abundance variations are coupled with a complex, extended, and multimodal blue horizontal branch (HB). The HB morphology and chemical abundances suggest that NGC 6273 may have an origin that is similar to omega Cen and M 54.Comment: Accepted for Publication in The Astrophysical Journal; 50 pages; 18 figures; 8 tables; higher resolution figures are available upon request or in the published journal articl

    One Health in food safety and security education: Subject matter outline for a curricular framework.

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    Educating students in the range of subjects encompassing food safety and security as approached from a One Health perspective requires consideration of a variety of different disciplines and the interrelationships among disciplines. The Western Institute for Food Safety and Security developed a subject matter outline to accompany a previously published One Health in food safety and security curricular framework. The subject matter covered in this outline encompasses a variety of topics and disciplines related to food safety and security including effects of food production on the environment. This subject matter outline should help guide curriculum development and education in One Health in food safety and security and provides useful information for educators, researchers, students, and public policy-makers facing the inherent challenges of maintaining and/or developing safe and secure food supplies without destroying Earth's natural resources

    Exploring the Chemical Composition and Double Horizontal Branch of the Bulge Globular Cluster NGC 6569

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    Photometric and spectroscopic analyses have shown that the Galactic bulge cluster Terzan 5 hosts several populations with different metallicities and ages that manifest as a double red horizontal branch (HB). A recent investigation of the massive bulge cluster NGC 6569 revealed a similar, though less extended, HB luminosity split, but little is known about the cluster's detailed chemical composition. Therefore, we have used high-resolution spectra from the Magellan-M2FS and VLT-FLAMES spectrographs to investigate the chemical compositions and radial velocity distributions of red giant branch and HB stars in NGC 6569. We found the cluster to have a mean heliocentric radial velocity of -48.8 km/s (sigma = 5.3 km/s; 148 stars) and a mean [Fe/H] =-0.87 dex (19 stars), but the cluster's 0.05 dex [Fe/H] dispersion precludes a significant metallicity spread. NGC 6569 exhibits light- and heavy-element distributions that are common among old bulge/inner Galaxy globular clusters, including clear (anti)correlations between [O/Fe], [Na/Fe], and [Al/Fe]. The light-element data suggest that NGC 6569 may be composed of at least two distinct populations, and the cluster's low mean [La/Eu] = -0.11 dex indicates significant pollution with r-process material. We confirm that both HBs contain cluster members, but metallicity and light-element variations are largely ruled out as sources for the luminosity difference. However, He mass fraction differences as small as delta Y ~ 0.02 cannot be ruled out and may be sufficient to reproduce the double HB.Comment: 72 pages, 14 figures, 8 tables; published in The Astronomical Journal; electronic versions of all tables are available in the published versio

    Channel Characterisation and Link Budget of MIMO Configuration in Near Field Magnetic Communication

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    Traditional radio communication has gained significantly from using multiple input and multiple output (MIMO) architecture in the system. Many wireless applications, such as wireless LAN and cellular network, have adopted this technology to improve their system performance. However, the effect of MIMO systems has not been investigated in the case of inductive near field short range communications. The purpose of this paper is to explore a new method for increasing the magnetic communication range using MIMO. Three system models includingMISO, SIMO and MIMO are proposed to characterize the number of transmitters and receivers to the link. These models have helped to extend not only the range but also the communication channel in NFMIC

    In vitro propagation of Solidago virgaurea L. through nodal culture

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    A reliable in vitro propagation protocol has been established from nodal segmentsof a highly valuable medicinal plant Solidago virgaurea L. The explants were cultured onMurashige and Skoog’s medium augmented with different concentrations andcombinations of plant growth regulators for shoot bud initiation and multiplications.Highest frequency of shoot proliferation (91.8 ± 0.64) and maximum number (12.1 ± 0.20) pernode was observed in Murashige and Skoog’s medium augmented with4.5 mg/l of Kinetinin combination with 0.5 mg/l of Indole -3- Acetic acid. Highest frequency (91.7 ± 1.43) ofrooting and maximum number (3.8 ± 0.28) of rootlet per shoot let was achieved onMurashige and Skoog’s medium fortified with 4.5 mg/l of Indole -3- Acetic acid incombination with 0.5 mg/l of Benzyl -6- amino purine. Regenerated plants weresuccessfully transferred to field (78%)

    Effects of sweep on controls

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    An analysis of the principal results of recent control-surface research pertinent to transonic flight has been made. An indication of the nature of the changes in control-surface characteristics above the critical speed of the wing and a preliminary design procedure for estimating the effectiveness of flap-type controls on swept wings are presented

    Heralded state preparation in a superconducting qubit

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    We demonstrate high-fidelity, quantum nondemolition, single-shot readout of a superconducting flux qubit in which the pointer state distributions can be resolved to below one part in 1000. In the weak excitation regime, continuous measurement permits the use of heralding to ensure initialization to a fiducial state, such as the ground state. This procedure boosts readout fidelity to 93.9% by suppressing errors due to spurious thermal population. Furthermore, heralding potentially enables a simple, fast qubit reset protocol without changing the system parameters to induce Purcell relaxation.Comment: 5 pages, 5 figure

    The Photoeccentric Effect and Proto-hot Jupiters. III. A Paucity of Proto-hot Jupiters on Super-eccentric Orbits

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    Gas giant planets orbiting within 0.1 AU of their host stars are unlikely to have formed in situ and are evidence for planetary migration. It is debated whether the typical hot Jupiter smoothly migrated inward from its formation location through the proto-planetary disk, or was perturbed by another body onto a highly eccentric orbit, which tidal dissipation subsequently shrank and circularized during close stellar passages. Socrates and collaborators predicted that the latter model should produce a population of super-eccentric proto-hot Jupiters readily observable by Kepler. We find a paucity of such planets in the Kepler sample, which is inconsistent with the theoretical prediction with 96.9% confidence. Observational effects are unlikely to explain this discrepancy. We find that the fraction of hot Jupiters with an orbital period P > 3 days produced by the star-planet Kozai mechanism does not exceed (at two-sigma) 44%. Our results may indicate that disk migration is the dominant channel for producing hot Jupiters with P > 3 days. Alternatively, the typical hot Jupiter may have been perturbed to a high eccentricity by interactions with a planetary rather than stellar companion, and began tidal circularization much interior to 1 AU after multiple scatterings. A final alternative is that early in the tidal circularization process at high eccentricities tidal circularization occurs much more rapidly than later in the process at low eccentricities, although this is contrary to current tidal theories
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