Weak gauge principle and electric charge quantization

Starting from a weak gauge principle we give a new and critical revision of the argument leading to charge quantization on arbitrary spacetimes. The main differences of our approach with respect to previous works appear on spacetimes with non trivial torsion elements on its second integral cohomology group. We show that in these spacetimes there can be topologically non-trivial configurations of charged fields which do not imply charge quantization. However, the existence of a non-exact electromagnetic field always implies the quantization of charges. Another consequence of the theory for spacetimes with torsion is the fact that it gives rise to two natural quantization units that could be identified with the electric quantization unit (realized inside the quarks) and with the electron charge. In this framework the color charge can have a topological origin, with the number of colors being related to the order of the torsion subgroup. Finally, we discuss the possibility that the quantization of charge may be due to a weak non-exact component of the electromagnetic field extended over cosmological scales.Comment: Latex2e, 24 pages, no figure

Magnetic vortex filament flows

We exhibit a variational approach to study the magnetic flow associated with a Killing magnetic field in dimension 3. In this context, the solutions of the Lorentz force equation are viewed as Kirchhoff elastic rods and conversely. This provides an amazing connection between two apparently unrelated physical models and, in particular, it ties the classical elastic theory with the Hall effect. Then, these magnetic flows can be regarded as vortex filament flows within the localized induction approximation. The Hasimoto transformation can be used to see the magnetic trajectories as solutions of the cubic nonlinear Schrödinger equation showing the solitonic nature of those.Ministerio de Educación y CienciaFondo Europeo de Desarrollo RegionalJunta de Andalucí

Decomposing socio-economic inequalities in leisure-time physical inactivity: the case of Spanish children

BACKGROUND: Physical inactivity is associated with an increased risk of all-cause mortality and entails a substantial economic burden for health systems. Also, the analysis of inequality in lifestyles for young populations may contribute to reduce health inequalities during adulthood. This paper examines the income-related inequality regarding leisure-time physical inactivity in Spanish children. METHODS: In this cross-sectional study based on the Spanish National Health Survey for 2011-12, concentration indices are estimated to measure socioeconomic inequalities in leisure-time physical inactivity. A decomposition analysis is performed to determine the factors that explain income-related inequalities. RESULTS: There is a significant socioeconomic gradient favouring the better-off associated with leisure-time physical inactivity amongst Spanish children, which is more pronounced in the case of girls. Income shows the highest contribution to total inequality, followed by education of the head of the household. The contribution of several factors (education, place of residence, age) significantly differs by gender. CONCLUSIONS: There is an important inequity in the distribution of leisure-time physical inactivity. Public policies aimed at promoting physical activity for children should prioritize the action into the most disadvantaged subgroups of the population. As the influence of determinants of health styles significantly differ by gender, this study points out the need of addressing the research on income-related inequalities in health habits from a gender perspective

Outcome of infection with omicron SARS‐CoV‐2 variant in patients with hematological malignancies : an EPICOVIDEHA survey report

International audienceSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has caused high mortality in patients with hematological malignancies (HM). 1 The newly emerged omicron variants of SARS-CoV-2 harbor multiple novel spike protein mutations that raise concerns about vaccine efficiency and antiviral efficacy of the available therapeutic monoclonal antibodies. 2 The first published clinical data in immunocompetent patients have found that infection with omicron variants is associated with reduced vaccine efficiency compared to the delta variants, but decreased hospital admission and mortality. 3,4 Preliminary, prepublished, data from a large case-control study have shown that the vaccine effect against omicron in immunocompromised patients, including HM patients, is even more reduced, but data regarding clinical outcomes are lacking. 5 The aim of this study was to describe risk factors, antiviral treatment and outcomes of SARS-CoV-2 omicron variant infection in 593 HM patients included in the EPICOVIDEHA registry. EPICOVIDEHA is an international open web-based registry for patients with HM infected with SARS-CoV-2. 1,6 Both hospitalized and nonhospitalized patients are eligible for inclusion. The questionnaire includes data on the HM, SARS-CoV-2 vaccination status, risk factors for severe COVID-19 infection, SARS-CoV-2 virus variant, antiviral treatment, and outcomes including mortality (eFigure 1 and eTable 4)