1,647 research outputs found

    New Wave of Component Reuse with Spring Framework - AP Case Study

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    The myth of component reuse has always been the “holy grail” of software engineering. The motivation var-ies from less time, effort and money expenditure to higher system quality and reliability which is especially impor-tant in the domain of high energy physics and accelerator controls. Identified as an issue by D. McIlroy in 1968 [1], it has been generally addressed in many ways with vari-ous success rates. But only recently with the advent of fresh ideas like the Spring Framework with its powerful yet simple “Inversion of Control” paradigm the solution to the problem has started to be surprisingly uncompli-cated. Gathered over years of experience this document explains best practices and lessons learned applied at CERN for the design of the operational software used to control the accelerator complex and focuses on features of the Spring Framework that render the component reuse achievable in practice. It also provides real life use cases of mission-critical control systems developed by the Ap-plication Section like the LHC Software Architecture (LSA), the Injector Control Architecture (InCA) or the Software Interlock System (SIS) that have built their own success mostly upon a stack of reusable software components

    Household decision-making about delivery in health facilities: evidence from Tanzania.

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    This study investigated how partners' perceptions of the healthcare system influence decisions about delivery-location in low-resource settings. A multistage population-representative sample was used in Kasulu district, Tanzania, to identify women who had given birth in the last five years and their partners. Of 826 couples in analysis, 506 (61.3%) of the women delivered in the home. In multivariate analysis, factors associated with delivery in a health facility were agreement of partners on the importance of delivering in a health facility and agreement that skills of doctors are better than those of traditional birth attendants. When partners disagreed, the opinion of the woman was more influential in determining delivery-location. Agreement of partners regarding perceptions about the healthcare system appeared to be an important driver of decisions about delivery-location. These findings suggest that both partners should be included in the decision-making process regarding delivery to raise rates of delivery at facility

    Metal abundances in PG1159 stars from Chandra and FUSE spectroscopy

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    We investigate FUSE spectra of three PG1159 stars and do not find any evidence for iron lines. From a comparison with NLTE models we conclude a deficiency of 1-1.5 dex. We speculate that iron was transformed into heavier elements. A soft X-ray Chandra spectrum of the unique H- and He-deficient star H1504+65 is analyzed. We find high neon and magnesium abundances and confirm that H1504+65 is the bare core of either a C-O or a O-Ne-Mg white dwarf.Comment: To be published in: Proceedings 13th European Workshop on White Dwarfs, NATO Science Series, 4 pages, 1 figur

    The virtual observatory service TheoSSA: Establishing a database of synthetic stellar flux standards. II. NLTE spectral analysis of the OB-type subdwarf Feige 110

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    In the framework of the Virtual Observatory (VO), the German Astrophysical Virtual Observatory (GAVO) developed the registered service TheoSSA (Theoretical Stellar Spectra Access). It provides easy access to stellar spectral energy distributions (SEDs) and is intended to ingest SEDs calculated by any model-atmosphere code, generally for all effective temperature, surface gravities, and elemental compositions. We will establish a database of SEDs of flux standards that are easily accessible via TheoSSA's web interface. The OB-type subdwarf Feige 110 is a standard star for flux calibration. State-of-the-art non-local thermodynamic equilibrium (NLTE) stellar-atmosphere models that consider opacities of species up to trans-iron elements will be used to provide a reliable synthetic spectrum to compare with observations. In case of Feige 110, we demonstrate that the model reproduces not only its overall continuum shape from the far-ultraviolet (FUV) to the optical wavelength range but also the numerous metal lines exhibited in its FUV spectrum. We present a state-of-the-art spectral analysis of Feige 110. We determined Teff=47 250±2000 KT_\mathrm{eff} = 47\,250 \pm 2000\,\mathrm{K}, log⁥g=6.00±0.20\log g = 6.00 \pm 0.20 and the abundances of He, N, P, S, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, and Ge. Ti, V, Mn, Co, Zn, and Ge were identified for the first time in this star. Upper abundance limits were derived for C, O, Si, Ca, and Sc. The TheoSSA database of theoretical SEDs of stellar flux standards guarantees that the flux calibration of astronomical data and cross-calibration between different instruments can be based on models and SEDs calculated with state-of-the-art model-atmosphere codes.Comment: 19 pages, 7 figure

    Energy Flow in Acoustic Black Holes

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    We present the results of an analysis of superradiant energy flow due to scalar fields incident on an acoustic black hole. In addition to providing independent confirmation of the recent results in [5], we determine in detail the profile of energy flow everywhere outside the horizon. We confirm explicitly that in a suitable frame the energy flow is inward at the horizon and outward at infinity, as expected on physical grounds.Comment: 8 pages, 9 figures, Comments added to discussion of energy flow and introductory section abbreviate

    FUSE Spectroscopy of the Two Prototype White Dwarfs With Signatures of a Super-hot Wind

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    The O VIII phenomenon describes the occurrence of ultra-high ionization absorption lines of the CNO elements (e.g. O VIII, N VII, C VI, and even Ne X) in the optical spectra hot of DO WDs

    CalFUSE v3: A Data-Reduction Pipeline for the Far Ultraviolet Spectroscopic Explorer

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    Since its launch in 1999, the Far Ultraviolet Spectroscopic Explorer (FUSE) has made over 4600 observations of some 2500 individual targets. The data are reduced by the Principal Investigator team at the Johns Hopkins University and archived at the Multimission Archive at Space Telescope (MAST). The data-reduction software package, called CalFUSE, has evolved considerably over the lifetime of the mission. The entire FUSE data set has recently been reprocessed with CalFUSE v3.2, the latest version of this software. This paper describes CalFUSE v3.2, the instrument calibrations upon which it is based, and the format of the resulting calibrated data files.Comment: To appear in PASP; 29 pages, 13 figures, uses aastex, emulateap
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