1,258 research outputs found
Globular Cluster Abundances from High-Resolution, Integrated-Light Spectroscopy. II. Expanding the Metallicity Range for Old Clusters and Updated Analysis Techniques
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 0.1 dex for globular clusters with metallicities as high as
[Fe/H]=, 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
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
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
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
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
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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