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

Association between anxiety and vascular dementia risk: new evidence and an updated meta-analysis

The association between anxiety and vascular dementia (VaD) is unclear. We aimed to reliably estimate the association between anxiety and VaD risk using meta-analysis to pool new results from a large community-based cohort (Zaragoza Dementia and Depression (ZARADEMP) study) and results from previous studies. ZARADEMP participants (n = 4057) free of dementia were followed up on for up to 12 years. Cases and subcases of anxiety were determined at baseline. A panel of four psychiatrists diagnosed incident cases of VaD by consensus. We searched for similar studies published up to October 2019 using PubMed and Web of Science. Observational studies reporting associations between anxiety and VaD risk, and adjusting at least for age, were selected. Odds ratios (ORs) from each study were combined using fixed-effects models. In the ZARADEMP study, the risk of VaD was 1.41 times higher among individuals with anxiety (95% CI: 0.75-2.68) compared with non-cases (p = 0.288). Pooling this result with results from two previous studies yielded an OR of 1.65 (95% CI: 1.07-2.53; p = 0.022). These findings indicate that anxiety is associated with an increased risk of VaD. Taking into account that anxiety is commonly observed in the elderly, treating and preventing it might reduce the prevalence and incidence of VaD. However, whether anxiety is a cause of a prodrome of VaD is still unknown, and future research is needed to clarify this