1,945 research outputs found
Metallicity dependence of HMXB populations
High-mass X-ray binaries (HMXBs) might have contributed a non-negligible
fraction of the energy feedback to the interstellar and intergalactic media at
high redshift, becoming important sources for the heating and ionization
history of the Universe. However, the importance of this contribution depends
on the hypothesized increase in the number of HMXBs formed in low-metallicity
galaxies and in their luminosities. In this work we test the aforementioned
hypothesis, and quantify the metallicity dependence of HMXB population
properties. We compile from the literature a large set of data on the sizes and
X-ray luminosities of HMXB populations in nearby galaxies with known
metallicities and star formation rates. We use Bayesian inference to fit simple
Monte Carlo models that describe the metallicity dependence of the size and
luminosity of the HMXB populations. We find that HMXBs are typically ten times
more numerous per unit star formation rate in low-metallicity galaxies (12 +
log(O/H) < 8, namely < 20% solar) than in solar-metallicity galaxies. The
metallicity dependence of the luminosity of HMXBs is small compared to that of
the population size. Our results support the hypothesis that HMXBs are more
numerous in low-metallicity galaxies, implying the need to investigate the
feedback in the form of X-rays and energetic mass outflows of these high-energy
sources during cosmic dawn.Comment: 9 pages, 5 figures, accepted for publication in Astronomy &
Astrophysic
Computer assisted audit tools and techniques in real world: CAATT's applications and approaches in context
Nowadays, Computer Aided Audit Tools (and Techniquesâ) support almost all audit processes concerning data extraction and analysis. These tools were firstly aimed to support financial auditing processes. However, their scope is beyond this, therefore, we present case studies and good practices in an academic context. Although in large auditing companies Audit Tools to do data extraction and analysis are very common and applied in several contexts, we realized that is not easy to find practical examples to teach this subject. Computer Science studentsâ and teachers usually use application manualsâ, which are adequate to explore the tools itself, but they are not enough to do real data analysis: a âhands-onâ approach is essential. Despite that, our students didnât belong to any Computer Science graduation. CAATTs are good examples of software aimed to help auditors to analyze data, to explore and study distinct data sets in auditing processes. CAATTs represent an innovative approach to do data analysis, mainly because they allow the manipulation of very large data records with no significant added costs. Frequently, users have another difficulty: they are not able to adequate their data sets or to prepare their data in order to create useful input data, to do their analysis. In this paper, we present a proposal of extraction and data analysis, based on data sets obtained from a LMS platform (Learning Management System), a real data set that can be used to support students learning about CAATTs topic. Fundamental procedures to reach specific answers using a CAATT as a main tool to do data extraction and analysis are also referred. The context for this case study was an Information Technologies applied to Auditing course in a Master Degree graduation
Determinants adoption of computer assisted auditing tools (CAATs)
During the last fifteen years, several studies on technology acceptance have been pursued, and several new models have been proposed. This paper presents a theoretical background on individual acceptance of Computer-assisted Audit Tools (CAATs) in the context of statutory auditors of a European country. The adoption of technologies in auditing is considered an important factor for efficiency increasing and effectiveness of auditing work. This study identifies the adoption determinants of CAATs; and develops a CAATs, adoption model. Quantitative research was carried out and operationalized by a survey to statutory auditors. Findings indicate that the perceived usefulness of CAATs, the effort expectancy, the facilitating conditions, and the number of auditors are the main drivers of the adoption and use of CAATs. This research presents significant contributions impacting the various stakeholders: Statutory Auditors, Statutory Auditors Firms, Institutes of Statutory Auditors, and Academy.info:eu-repo/semantics/acceptedVersio
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