1,252 research outputs found

    Globular Cluster Abundances from High-Resolution, Integrated-Light Spectroscopy. II. Expanding the Metallicity Range for Old Clusters and Updated Analysis Techniques

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    We present abundances of globular clusters in the Milky Way and Fornax from integrated light spectra. Our goal is to evaluate the consistency of the integrated light analysis relative to standard abundance analysis for individual stars in those same clusters. This sample includes an updated analysis of 7 clusters from our previous publications and results for 5 new clusters that expand the metallicity range over which our technique has been tested. We find that the [Fe/H] measured from integrated light spectra agrees to ∼\sim0.1 dex for globular clusters with metallicities as high as [Fe/H]=−0.3-0.3, but the abundances measured for more metal rich clusters may be underestimated. In addition we systematically evaluate the accuracy of abundance ratios, [X/Fe], for Na I, Mg I, Al I, Si I, Ca I, Ti I, Ti II, Sc II, V I, Cr I, Mn I, Co I, Ni I, Cu I, Y II, Zr I, Ba II, La II, Nd II, and Eu II. The elements for which the integrated light analysis gives results that are most similar to analysis of individual stellar spectra are Fe I, Ca I, Si I, Ni I, and Ba II. The elements that show the greatest differences include Mg I and Zr I. Some elements show good agreement only over a limited range in metallicity. More stellar abundance data in these clusters would enable more complete evaluation of the integrated light results for other important elements.Comment: Accepted for publication in ApJ, 37 pages, 13 tables, 29 figure

    Potential Uses of Embedded RFID in Appliance Identification

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    Radio Frequency Identification (RFID) has become a pervasive technology for the purpose of tracking goods through the supply chain. It is possible to adapt this radio technology such that remote identification is possible using the electrical power cable as a communication channel in place of the inductive coils used by most RFID tags. Furthermore, passive transponders which do not require a local power source may be used. This opens up several interesting possibilities for automatic appliance identification during manufacture, test and in general use

    The Evolution of Oxygen and Magnesium in the Bulge and Disk of the Milky Way

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    We show that the Galactic bulge and disk share a similar, strong, decline in [O/Mg] ratio with [Mg/H]. The similarity of the [O/Mg] trend in these two, markedly different, populations suggests a metallicity-dependent modulation of the stellar yields from massive stars, by mass loss from winds, and related to the Wolf-Rayet phenomenon, as proposed by McWilliam & Rich (2004). We have modified existing models for the chemical evolution of the Galactic bulge and the solar neighborhood with the inclusion of metallicity-dependent oxygen yields from theoretical predictions for massive stars that include mass loss by stellar winds. Our results significantly improve the agreement between predicted and observed [O/Mg] ratios in the bulge and disk above solar metallicity; however, a small zero-point normalization problem remains to be resolved. The zero-point shift indicates that either the semi-empirical yields of Francois et al. (2004) need adjustment, or that the bulge IMF is not quite as flat as found by Ballero et al. (2007); the former explanation is preferred. Our result removes a previous inconsistency between the interpretation of [O/Fe] and [Mg/Fe] ratios in the bulge, and confirms the conclusion that the bulge formed more rapidly than the disk, based on the over-abundances of elements produced by massive stars. We also provide an explanation for the long-standing difference between [Mg/Fe] and [O/Fe] trends among disk stars more metal-rich than the sun.Comment: 22 pages including 5 figures. Submitted to the Astronomical Journa

    Modelling Electronic Circuit Failures using a Xilinx FPGA System

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    FPGAs are a ubiquitous electronic component utilised in a wide range of electronic systems across many industries. Almost all modern FPGAs employ SRAM based configuration memory elements which are susceptible to radiation induced soft errors. In high altitude and space applications, as well as in the nuclear and defence industries, such circuits must operate reliably in radiation-rich environments. A range of soft error mitigation techniques have been proposed but testing and qualification of new fault tolerant circuits can be an expensive and time consuming process. A novel method for simulating radiation-induced soft errors is presented that operates entirely within a laboratory environment and requires no hazardous exposure to radiation or expensive airborne test rigs. A system utilising modular redundancy is then implemented and tested under the new method. The test system is further demonstrated in conjunction with a software flight simulator to test single electronic modules in the context of active service on board a passenger aircraft and the effects of failure under radiation induced soft errors are observed. Our research proposes a test regime in which design strategies for self-healing circuits can be compared and demonstrated to work

    A Training Program to Improve IFSP/IEP Goals and Objectives Through the Routines-Based Interview

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    WOS:000329323800001 (Nº de Acesso Web of Science)The authors describe a training program designed to improve the knowledge and skills of early childhood interventionists. Within the context of using the Routines-Based Early Intervention approach, this training focused on improving the quality of goals and objectives on individualized plans, through the Routines-Based Interview. We structured the training around five face-to-face sessions and a follow-up 3 months later. Here, we describe the development of the program, its content and methods, and the results on improvement of the goals and objectives with 80 professionals. These participants had completed the training, provided pretraining data, and provided posttraining data. Results showed that the training described here had the desired very large effect: Quality ratings of goals and objectives increased by over three standard deviations

    Coordinates and 2MASS and OGLE identifications for all stars in Arp's 1965 finding chart for Baade's Window

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    Aims: We seek to provide 2MASS and OGLE identifications and coordinates for all stars in the finding chart published by Arp\,(1965). This chart covers the low extinction area around NGC 6522, also known as Baade's window, at coordinates (l,b)=(1.02,-3.92). Methods: A cross correlation, using numerical techniques, was performed between a scan of the original finding chart from Arp (1965) and 2MASS and OGLE-II images and stellar coordinates. Results: We provide coordinates for all stars in Arp's finding chart and 2MASS and OGLE identifications wherever possible. Two identifications in quadrant II do not appear in the original finding chart.Comment: 30 pages, accepted by A&A as a Research Not
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