Witten's cubic vertex in the comma theory (I)

It is shown that Witten's interaction 3-vertex is a solution to the comma overlap equations; hence establishing the equivalence between the conventional and the 'comma' formulation of interacting string theory at the level of vertices

Bottom quark mass and QCD duality

The mass of the bottom quark is analyzed in the context of QCD finite energy sum rules. In contrast to the conventional approach, we use a large momentum expansion of the QCD correlator including terms to order alpha(S)(2)(m(b)(2)/q(2))(6) with the upsilon resonances from e(+)c(-) annihilation data as main input. A stable result m(b)(m(b)) = (4.19 +/- 0.05) GeV for the bottom quark mass is obtained. This result agrees with the independent calculations based on the inverse moment analysis

Prevalence of post-traumatic stress disorder (PTSD) in university students during the COVID-19 pandemic: a meta-analysis attending SDG 3 and 4 of the 2030 agenda

Background: Most universities around the world have been heavily affected by the COVID-19 pandemic, as declared by the World Health Organization (WHO) in March 2020. Many students were isolated at home and underwent a forced transition from face-to-face learning to e-learning, at least in the first few months. The subsequent months and years were typically characterised by a slow return to normal learning under COVID-19 protocols and restrictions. A potential consequence of the lockdowns, social restrictions and changes to learning is the development of PTSD (post-traumatic stress disorder) in university students, affecting their health and well-being (SDG3) and quality of education (SDG4). Materials and Methods: Medline was searched through PubMed for studies on the prevalence of PTSD in university students from 1 December 2019 to 31 December 2021. The pooled prevalence of PTSD was calculated with random-effects models. Results: A total of six studies were included, across which the prevalence of PTSD among university students was 23%. Meta-regression showed that the prevalence of PTSD was significantly higher with older age, but independent of the percentage of women in a study or its methodological quality. Conclusions: Our results suggest that students suffer from PTSD at a moderate rate. Measures are needed to address the mental health issues of university students that have arisen during COVID-19 all around the world. © 2022 by the authors. Licensee MDPI, Basel, Switzerland

The Geant4-DNA project

The Geant4-DNA project proposes to develop an open-source simulation software based and fully included in the general-purpose Geant4 Monte Carlo simulation toolkit. The main objective of this software is to simulate biological damages induced by ionising radiation at the cellular and sub-cellular scale. This project was originally initiated by the European Space Agency for the prediction of deleterious effects of radiation that may affect astronauts during future long duration space exploration missions. In this paper, the Geant4-DNA collaboration presents an overview of the whole ongoing project, including its most recent developments already available in the last Geant4 public release (9.3 BETA), as well as an illustration example simulating the direct irradiation of a chromatin fibre. Expected extensions involving several research domains, such as particle physics, chemistry and cellular and molecular biology, within a fully interdiciplinary activity of the Geant4 collaboration are also discussed.Comment: presented by S. Incerti at the ASIA SIMULATION CONFERENCE 2009, October 7-9, 2009, Ritsumeikan University, Shiga, Japa

QCD sum rule determination of the charm-quark mass

QCD sum rules involving mixed inverse moment integration kernels are used in order to determine the running charm-quark mass in the MS¯ scheme. Both the high and the low energy expansion of the vector current correlator are involved in this determination. The optimal integration kernel turns out to be of the form p(s)=1−(s0/s)2, where s0 is the onset of perturbative QCD. This kernel enhances the contribution of the well known narrow resonances, and reduces the impact of the data in the range s≃20−25GeV2. This feature leads to a substantial reduction in the sensitivity of the results to changes in s0, as well as to a much reduced impact of the experimental uncertainties in the higher resonance region. The value obtained for the charm-quark mass in the MS¯ scheme at a scale of 3 GeV is m¯c(3GeV)=987±9MeV, where the error includes all sources of uncertainties added in quadrature

Cloning and Characterization of Canine \u3cem\u3ePAX6\u3c/em\u3e and Evaluation as a Candidate Gene in a Canine Model of Aniridia

Purpose: Mutations in PAX6 cause human aniridia. The small eye (sey) mouse represents an animal model for aniridia. However, no large animal model currently exists. We cloned and characterized canine PAX6, and evaluated PAX6 for causal associations with inherited aniridia in dogs. Methods: Canine PAX6 was cloned from a canine retinal cDNA library using primers designed from human and mouse PAX6 consensus sequences. An RH3000 radiation hybrid panel was used to localize PAX6 within the canine genome. Genomic DNA was extracted from whole blood of dogs with inherited aniridia, and association testing was performed using markers on CFA18. Fourteen PAX6 exons were sequenced and scanned for mutations, and a Southern blot was used to test for large deletions. Results: Like the human gene, canine PAX6 has 13 exons and 12 introns, plus an alternatively spliced exon (5a). PAX6 nucleotide and amino acid sequences were highly conserved between dog, human, and mouse. The canine PAX6 cDNA sequence determined in this study spans 2 large gaps present in the current canine genomic sequence. Radiation hybrid mapping placed canine PAX6 on CFA18 in a region with synteny to HSA11p13. Exon-scanning revealed single nucleotide polymorphisms, but no pathological mutations, and Southern blot analysis revealed no differences between normal and affected animals. Conclusions: Canine PAX6 was cloned and characterized, and results provide sequence information for gaps in the current canine genome sequence. Canine PAX6 nucleotide and amino acid sequences, as well as gene organization and map location, were highly homologous with that of the human gene. PAX6 was evaluated in dogs with an inherited form of aniridia, and sequence analysis indicated no pathological mutations in the coding regions or splice sites of aniridia-affected dogs, and Southern blot analysis showed no large deletions