scholarly journals The Belgian Repository of Fundamental Atomic Data and Stellar Spectra (BRASS) Identifying Fruitful Methods for Producing Atomic Data

Galaxies ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 78 ◽  
Author(s):  
Mike Laverick ◽  
Alex Lobel ◽  
Pierre Royer ◽  
Christophe Martayan ◽  
Thibault Merle ◽  
...  

The Belgian repository of fundamental atomic data and stellar spectra (BRASS) aims to provide the largest systematic and homogeneous quality assessment to-date of input atomic data required for stellar spectral synthesis. In addition to quality-assessed atomic data, BRASS shall also provide of a range of extremely high-quality benchmark stellar spectra spanning late B-type stars to early K-type stars. In this paper, we summarise the project’s progress and available results to-date. We provide a brief comparison between our results and the BRASS project’s compiled and cross-matched atomic literature, with the goal of providing useful feedback to the atomic community on which methods may produce more reliable and accurate atomic data. We hope that the examples presented here stimulate further investigation by the atomic physics community.

2019 ◽  
Vol 15 (S350) ◽  
pp. 386-387
Author(s):  
M. Laverick ◽  
A. Lobel ◽  
P. Royer ◽  
T. Merle ◽  
C. Martayan ◽  
...  

AbstractThe Belgian Repository of fundamental Atomic data and Stellar Spectra (BRASS) aims to provide one of the largest systematic and homogeneous quality assessment to date of literature atomic data required for stellar spectroscopy. By comparing state-of-the-art synthetic spectrum calculations with extremely high-quality observed benchmark spectra, we have critically evaluated fundamental atomic data, such as line wavelengths and oscillator strengths, for thousands of astrophysically-relevant transitions found in the literature and across several major atomic data repositories. These proceedings provide a short overview of the BRASS project to date, highlighting our recent efforts to investigate and quality-assess the atomic literature data pertaining to over a thousand atomic transitions present in FGK-type stellar spectra. BRASS provides all quality assessed data, theoretical spectra, and observed spectra in a new interactive database under development at brass.sdf.org.


2017 ◽  
Vol 95 (9) ◽  
pp. 843-846 ◽  
Author(s):  
M. Laverick ◽  
A. Lobel ◽  
P. Royer ◽  
C. Martayan ◽  
T. Merle

The Belgian repository of fundamental atomic data and stellar spectra (BRASS) aims to critically evaluate atomic data, from publicly available repositories, by comparing state-of-the-art synthetic spectra against high-quality benchmark stellar spectra. In preparation for our assessment we have cross-matched atomic line transitions from several different databases. Our investigation revealed significant updates in log(gf) values, sometimes as large as 2–4 dex, that fully justify the need for systematic quality assessments of the atomic data. We have also investigated the spectral line blending of an initial subset of 2647 atomic lines using spectral synthesis calculations, for the spectral types BAFGK.


2019 ◽  
Vol 624 ◽  
pp. A60 ◽  
Author(s):  
M. Laverick ◽  
A. Lobel ◽  
P. Royer ◽  
T. Merle ◽  
C. Martayan ◽  
...  

Context. Fundamental atomic transition parameters, such as oscillator strengths and rest wavelengths, play a key role in modelling and understanding the chemical composition of stars in the universe. Despite the significant work under way to produce these parameters for many astrophysically important ions, uncertainties in these parameters remain large and can limit the accuracy of chemical abundance determinations.Aims. The Belgian repository of fundamental atomic data and stellar spectra (BRASS) aims to provide a large systematic and homogeneous quality assessment of the atomic data available for quantitative spectroscopy. BRASS shall compare synthetic spectra against extremely high-quality observed spectra, at a resolution of ∼85 000 and signal-noise ratios of ∼1000, for approximately 20 bright BAFGK spectral-type stars, in order to critically evaluate the atomic data available for over a thousand potentially useful spectral lines.Methods. A large-scale homogeneous selection of atomic lines is performed by synthesising theoretical spectra of literature atomic lines for FGK-type stars including the Sun, resulting in a selection of 1091 theoretically deep and unblended lines in the wavelength range 4200–6800 Å, which may be suitable for quality assessment. Astrophysical log(g f) values are determined for the 1091 transitions using two commonly employed methods. The agreement of these log(g f) values are used to select well-behaved lines for quality assessment.Results. We found 845 atomic lines to be suitable for quality assessment, of which 408 were found to be robust against systematic differences between analysis methods. Around 53% of the quality-assessed lines were found to have at least one literature log(g f) value in agreement with our derived values, though the remaining values can disagree by as much as 0.5 dex. Only ∼38% of Fe Ilines were found to have sufficiently accurate log(g f) values, increasing to ∼70–75% for the remaining Fe-group lines.


Author(s):  
Tatiana Ryabchikova ◽  
Yury Pakhomov ◽  
Nikolai Piskunov

Vienna Atomic Line Database (VALD) contains data on atomic and molecular energy levels and parameters of spectral lines required for stellar spectra analysis. Hundreds of millions lines for fine spectral synthesis and for opacity calculations are collected in present version of VALD (VALD3). Critical evaluation of the data and the diversity of extraction tools support high popularity of VALD among users. The data model of VALD3 incorporates obligatory links to the bibliography making our database more attractive as publishing platform for data producers. The VALD data quality and completeness are constantly improving allowing better reproduction of stellar spectra. To illustrate continuous evolution of the data content we present a comparative analysis of the recent experimental and theoretical atomic data for Fe-group elements, which will be included in the next VALD release. This release will also include a possibility for extracting the line data with full isotopic and hyperfine structures.


2018 ◽  
Vol 14 (A30) ◽  
pp. 458-462
Author(s):  
Ulrike Heiter

AbstractHigh-precision spectroscopy of large stellar samples plays a crucial role for several topical issues in astrophysics, such as studying the chemical evolution of the Milky Way Galaxy. Data are accumulating from instruments that obtain high-quality spectra of stars in the ultraviolet, optical and infrared wavelength regions on a routine basis. The interpretation of these spectra is often based on synthetic stellar spectra, either calculated on the fly or taken from a spectral library. One of the most important ingredients of these spectra is a set of high-quality transition data for numerous species, in particular neutral and singly ionized atoms. We rely heavily on the continuous activities of laboratory astrophysics groups that produce and improve the relevant experimental and theoretical atomic data. As an example, we briefly describe the efforts done in the context of the Gaia-ESO Public Spectroscopic Survey to compile and assess the best available data in a standard way, providing a list of recommended lines for analysis of optical spectra of FGK stars. The line data, together with specialised analysis methods, allow different surveys to obtain abundances with typical precisions of ∼0.1 dex on an industrial scale for ∼10 chemical elements. Several elements with urgent need for better atomic data have been identified.


1966 ◽  
Vol 24 ◽  
pp. 51-52
Author(s):  
E. K. Kharadze ◽  
R. A. Bartaya

The unique 70-cm meniscus-type telescope of the Abastumani Astrophysical Observatory supplied with two objective prisms and the seeing conditions characteristic at Mount Kanobili (Abastumani) permit us to obtain stellar spectra of a high quality. No additional design to improve the “climate” immediately around the telescope itself is being applied. The dispersions and photographic magnitude limits are 160 and 660Å/mm, and 12–13, respectively. The short-wave end of spectra reaches 3500–3400Å.


Author(s):  
Анна Юрьевна Белякова ◽  
Алена Алексеевна Самохвалова

В статье рассматривается определение остаточных знаний студентов. Для более эффективной и качественной оценки знаний по дисциплинам профессионального блока у студентов направления 09.03.03 - Прикладная информатика предлагается автоматизировать данный процесс. The article discusses the definition of residual knowledge of students. For a more efficient and high-quality assessment of knowledge in the disciplines of the professional block among students of the direction 09.03.03 - Applied Informatics, it is proposed to automate this process.


2018 ◽  
Vol 7 (4) ◽  
pp. e000353 ◽  
Author(s):  
Luke A Turcotte ◽  
Jake Tran ◽  
Joshua Moralejo ◽  
Nancy Curtin-Telegdi ◽  
Leslie Eckel ◽  
...  

BackgroundHealth information systems with applications in patient care planning and decision support depend on high-quality data. A postacute care hospital in Ontario, Canada, conducted data quality assessment and focus group interviews to guide the development of a cross-disciplinary training programme to reimplement the Resident Assessment Instrument–Minimum Data Set (RAI-MDS) 2.0 comprehensive health assessment into the hospital’s clinical workflows.MethodsA hospital-level data quality assessment framework based on time series comparisons against an aggregate of Ontario postacute care hospitals was used to identify areas of concern. Focus groups were used to evaluate assessment practices and the use of health information in care planning and clinical decision support. The data quality assessment and focus groups were repeated to evaluate the effectiveness of the training programme.ResultsInitial data quality assessment and focus group indicated that knowledge, practice and cultural barriers prevented both the collection and use of high-quality clinical data. Following the implementation of the training, there was an improvement in both data quality and the culture surrounding the RAI-MDS 2.0 assessment.ConclusionsIt is important for facilities to evaluate the quality of their health information to ensure that it is suitable for decision-making purposes. This study demonstrates the use of a data quality assessment framework that can be applied for quality improvement planning.


2021 ◽  
Vol 20 ◽  
pp. 153473542110660
Author(s):  
Megan E. Sansevere ◽  
Jeffrey D. White

Background: Complementary and alternative medicine (CAM) is often used by cancer patients and survivors in the US. Many people turn to the internet as their first source of information. Health information seeking through the internet can be useful for patients to gain a better understanding of specific CAM treatments to discuss with their healthcare team, but only if the information is comprehensive, high quality, and reliable. The aim of this article is to examine the content, writing/vetting processes, and visibility of cancer CAM online informational resources. Methods: Online CAM resources were identified by Google and PubMed searches, literature reviews, and through sources listed on various websites. The websites were analyzed through a modified online health information evaluation tool, DISCERN (score range = 1-5). The website’s features relevant to the quality assessment were described. Results: Eleven CAM websites were chosen for analysis. The DISCERN analysis showed a range of quality scores from 3.6 to 4.9. Lower DISCERN scores were generally due to deficiencies in describing the writing, editing, and updating processes. A lack of transparency with authorship and references was commonly present. Conclusion: Cancer patients interested in CAM need unbiased, evidence-based, reliable, high-quality, easily accessible educational materials. Individuals should use the guidelines followed in this analysis (including DISCERN and Medline Plus) to find reliable sources. Website developers can use CAM Cancer (NAFKAM), Beyond Conventional Cancer Therapies, Memorial Sloan Kettering Cancer Center, breastcancer.org , Office of Dietary Supplements, National Center for Complementary and Integrative Health, and Cancer.gov as models for trustworthy content.


2007 ◽  
Vol 53 (2) ◽  
pp. 164-172 ◽  
Author(s):  
Mariska Leeflang ◽  
Johannes Reitsma ◽  
Rob Scholten ◽  
Anne Rutjes ◽  
Marcello Di Nisio ◽  
...  

Abstract Background: We examined whether and to what extent different strategies of defining and incorporating quality of included studies affect the results of metaanalyses of diagnostic accuracy. Methods: We evaluated the methodological quality of 487 diagnostic-accuracy studies in 30 systematic reviews with the QUADAS (Quality Assessment of Diagnostic-Accuracy Studies) checklist. We applied 3 strategies that varied both in the definition of quality and in the statistical approach to incorporate the quality-assessment results into metaanalyses. We compared magnitudes of diagnostic odds ratios, widths of their confidence intervals, and changes in a hypothetical clinical decision between strategies. Results: Following 2 definitions of quality, we concluded that only 70 or 72 of 487 studies were of “high quality”. This small number was partly due to poor reporting of quality items. None of the strategies for accounting for differences in quality led systematically to accuracy estimates that were less optimistic than ignoring quality in metaanalyses. Limiting the review to high-quality studies considerably reduced the number of studies in all reviews, with wider confidence intervals as a result. In 18 reviews, the quality adjustment would have resulted in a different decision about the usefulness of the test. Conclusions: Although reporting the results of quality assessment of individual studies is necessary in systematic reviews, reader wariness is warranted regarding claims that differences in methodological quality have been accounted for. Obstacles for adjusting for quality in metaanalyses are poor reporting of design features and patient characteristics and the relatively low number of studies in most diagnostic reviews.


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