Octet-baryon masses in finite space

We report on a recent study of finite-volume effects on the lowest-lying octet baryon masses using the covariant baryon chiral perturbation theory up to next-to-leading order by analysing the latest $n_f = 2 + 1$ lattice QCD results from the NPLQCD Collaboration.Comment: 4 pages, 1 figure; parallel talk delivered by XLR at the 14th national conference on nuclear structure, April 12nd - 16th, 2012, Huzhou, Chin

Innovation Driven by Human and Organizational Factors (HOF) in Risk Assessment Methodologies and Standards: ATEX (Explosive Atmosphere) Risk Assessment Application

ATEX (explosive atmosphere) risk assessment is required when any equipment or system potentially causes explosive atmospheres. Despite many operations on plant and equipment containing dangerous substances are performed by operators, influences of human and organizational factor (HOF) are mostly neglected. This research work, according to the overview of the general risk assessment and human factor integration techniques, focuses on the HOF influence on a specific application domain: the ATEX (explosive atmosphere) risk assessment domain. The integrated ATEX risk assessment methodology with HOF is proposed. The ATEX-HOF methodology provides a quantitative risk analysis approach with taking into account of HOF. Inside each phase, clearly assessment goals are identified which are enable to conduct the ATEX risk assessment with simplified ‘step-by-step’. An event tree based probabilistic assessment has been introduced, which is taking into account both the technical barrier failure (Prtbf) and the human intervention (e.g. operational failure, and/or operational barrier failure) in terms of Human Error Probability (HEP). Hence, the ATEX-HOF risk assessment becomes more complete than the traditional approach. Two on-site applications shown how taking into account HOFs is particular important in companies where the safety culture is lower and consequently the usual hypothesis of the correctness of operator intervention (in maintenance, normal operations, and emergency) could bring to not conservative results. The applied operational (HOF) barriers explicated in the analysis can be used to support for defining a more detailed set of operational procedures, which is able to maintain the risk level evaluated. In addition, since several accident investigations have found that 80% correspond to human error, in nowadays, the change in safety has focused on developing good safety cultures that positively influence human behaviour at work to reduce errors and violations. HOF as the major consideration within the safety culture plays an important role in the Safety Management System (SMS). Safety culture is not a difficult idea, but it is generally considered as “trust”, “values” and “attitudes”, which is difficult to clarify the meaning in practise. The Event tree based probabilistic assessment method has been introduced to quantify the HOF influence. This research, hence, can be concerned as an attempt to handle safety cultures in practice via the integration of the risk assessment

Scalar strangeness content of the nucleon and baryon sigma terms

The scalar strangeness content of the nucleon, characterized by the so-called strangeness-nucleon sigma term, is of fundamental importance in understanding its sea-quark flavor structure. We report a determination of the octet baryon sigma terms via the Feynman-Hellmann theorem by analyzing the latest high-statistics $n_f=2+1$ lattice QCD simulations with covariant baryon chiral perturbation theory up to next-to-next-to-next-to-leading order. In particular, we predict $\sigma_{\pi N}=55(1)(4)$ MeV and $\sigma_{sN}=27(27)(4)$ MeV, while the first error is statistical and the second systematic due to different lattice scales. The predicted $\sigma_{sN}$ is consistent with the latest LQCD results and the results based on the next-to-next-to-leading order chiral perturbation theory. Several key factors in determining the sigma terms are systematically taken into account and clarified for the first time, including the effects of lattice scale setting, systematic uncertainties originating from chiral expansion truncations, and constraint of strong-interaction isospin breaking effects.Comment: 6 pages, 2 figures; version to appear in Physical Review

Octet baryon masses and sigma terms in covariant baryon chiral perturbation theory

We report an analysis of the octet baryon masses using the covariant baryon chiral perturbation theory up to next-to-next-to-next-to-leading order with and without the virtual decuplet contributions. Particular attention is paid to the finite-volume corrections and the finite lattice spacing effects on the baryon masses. A reasonable description of all the publicly available $n_f=2+1$ lattice QCD data is achieved.Utilyzing the Feynman-Hellmann theorem, we determine the nucleon sigma terms as $\sigma_{\pi N}=55(1)(4)$ MeV and $\sigma_{sN}=27(27)(4)$ MeV.Comment: 4 pages; presented by Xiu-Lei Ren at The Seventh International Symposium on Chiral Symmetry in Hadrons and Nuclei (Chiral 2013), October 27-30, 2013, Beijing, Chin

A Taxonomy of Hyperlink Hiding Techniques

Hidden links are designed solely for search engines rather than visitors. To get high search engine rankings, link hiding techniques are usually used for the profitability of black industries, such as illicit game servers, false medical services, illegal gambling, and less attractive high-profit industry, etc. This paper investigates hyperlink hiding techniques on the Web, and gives a detailed taxonomy. We believe the taxonomy can help develop appropriate countermeasures. Study on 5,583,451 Chinese sites' home pages indicate that link hidden techniques are very prevalent on the Web. We also tried to explore the attitude of Google towards link hiding spam by analyzing the PageRank values of relative links. The results show that more should be done to punish the hidden link spam.Comment: 12 pages, 2 figure