Model-independent approach to eta -> pi+ pi- gamma and eta' -> pi+ pi- gamma

We present a new, model-independent method to analyze radiative decays of mesons to a vector, isovector pair of pions of invariant mass square below the first significant pion-pion threshold in the vector channel. It is based on a combination of chiral perturbation theory and dispersion theory. This allows for a controlled inclusion of resonance physics without the necessity to involve vector meson dominance explicitly. As an example, the method is applied to an analysis of the reactions eta -> pi+ pi- gamma and eta'->pi+ pi- gamma.Comment: 16 pages, 4 figure

Optimal vaccine allocation for the control of sexually transmitted infections

The burden of sexually transmitted infections (STIs) poses a challenge due to its large negative impact on sexual and reproductive health worldwide. Besides simple prevention measures and available treatment efforts, prophylactic vaccination is a powerful tool for controlling some viral STIs and their associated diseases. Here, we investigate how prophylactic vaccines are best distributed to prevent and control STIs. We consider sex-specific differences in susceptibility to infection, as well as disease severity outcomes. Different vaccination strategies are compared assuming distinct budget constraints that mimic a scarce vaccine stockpile. Vaccination strategies are obtained as solutions to an optimal control problem subject to a two-sex Kermack– McKendrick-type model, where the control variables are the daily vaccination rates for females and males. One important aspect of our approach relies on conceptualizing a limited but specific vaccine stockpile via an isoperimetric constraint. We solve the optimal control problem via Pontryagin’sMaximum Principle and obtain a numerical approximation for the solution using a modified version of the forward–backward sweep method that handles the isoperimetric budget constraint in our formulation. The results suggest that for a limited vaccine supply (20%–30%vaccination coverage), onesex vaccination, prioritizing females, appears to be more beneficial than the inclusion of both sexes into the vaccination program.Whereas, if the vaccine supply is relatively large (enough to reach at least 40% coverage), vaccinating both sexes, with a slightly higher rate for females, is optimal and provides an effective and faster approach to reducing the prevalence of the infection

Modeling spillover dynamics: understanding emerging pathogens of public health concern

The emergence of infectious diseases with pandemic potential is a major public health threat worldwide. The World Health Organization reports that about 60% of emerging infectious diseases are zoonoses, originating from spillover events. Although the mechanisms behind spillover events remain unclear, mathematical modeling offers a way to understand the intricate interactions among pathogens, wildlife, humans, and their shared environment. Aiming at gaining insights into the dynamics of spillover events and the outcome of an eventual disease outbreak in a population, we propose a continuous time stochastic modeling framework. This framework links the dynamics of animal reservoirs and human hosts to simulate cross-species disease transmission. We conduct a thorough analysis of the model followed by numerical experiments that explore various spillover scenarios. The results suggest that although most epidemic outbreaks caused by novel zoonotic pathogens do not persist in the human population, the rising number of spillover events can avoid long-lasting extinction and lead to unexpected large outbreaks. Hence, global efforts to reduce the impacts of emerging diseases should not only address post-emergence outbreak control but also need to prevent pandemics before they are established

Dispersive analysis for η→γγ∗\eta\to \gamma\gamma^*

A dispersion integral is derived that connects data on $\eta\to \pi^+\pi^-\gamma$ to the $\eta\to \gamma\gamma^*$ transition form factor. A detailed analysis of the uncertainties is provided. We find for the slope of the $\eta$ transition form factor at the origin $b_\eta = (2.05 {}^{+0.22}_{-0.10})\, {\rm GeV}^{-2}$. Using an additional, plausible assumption, one finds for the corresponding slope of the $\eta'$ transition form factor, $b_{\eta'} = (1.58 {}^{+0.15}_{-0.08})\, {\rm GeV}^{-2}$. Both values are consistent with all recent data, but differ from some previous theoretical analyses.Comment: 11 pages, 3 figures, 2 tables (with extended discussion of the isoscalar contribution to the transition form factor

Разработка метода темплатного синтеза наноструктур в алюмооксидных матрицах

Объектом исследования является разработка метода темплатного синтеза наноструктур в алюмооксидных матрицах. Цель работы являются синтез матрицы АОА методом двухступенчатого анодирования и разработка методики темплатного синтеза металлических наноструктур в матрице АОА. Область применения: мембранные технологии, оптика, микроэлектронные устройства, матрицы для темплатного синтеза. В будущем планируется проведение исследования нанокомпозитов на основе кобальта, полученных в матрице АОА, изучение режима формирования наноструктуры и применения таких материалов.The object of research is the development of a template synthesis method for nanostructures in alumina matrices. The aim of the work is the synthesis of the AOA matrix by the method of two-stage anodization and the development of a template synthesis technique for metal nanostructures in the AOA matrix. Scope: membrane technologies, optics, microelectronic devices, matrices for template synthesis. In the future, it is planned to conduct research on cobalt-based nanocomposites obtained in the AOA matrix, to study the regime of nanostructure formation and the use of such materials.In the future, it is planned to conduct research on cobalt-base

Complex Network Approaches for Epidemic Modeling: A Case Study of COVID-19

Since the SARS-CoV-2 outbreak, the importance of mathematical modeling as a tool for comprehending disease dynamics has been highlighted, with several mathematical modeling techniques being applied and developed to simulate and measure the impact of interventions aimed at controlling the spread of the disease and minimizing its burden. In this work, we applied complex network techniques to analyze a Susceptible-Exposed-Asymptomatic-Hospitalized-Recovered (SEAHR) model to describe COVID-19 transmission dynamics, using the Basque Country region of Spain as a case study. We compared two network modeling approaches: the Watts-Strogatz network and the Barabasi-Albert scale-free network. By applying immunization strategies on both networks, we demonstrate that targeted immunization yields superior results within a scale-free network due to its increased heterogeneity. Moreover, the basic reproduction number of the model is calculated, and sensitivity analysis is performed to determine the influence of the model parameters on the disease dynamics.Juan de la Cierva Formación grant FJC2021-046826-I

Quasi-Neutral theory of epidemic outbreaks

Some epidemics have been empirically observed to exhibit outbreaks of all possible sizes, i.e., to be scalefree or scale-invariant. Different explanations for this finding have been put forward; among them there is a model for "accidental pathogens" which leads to power-law distributed outbreaks without apparent need of parameter fine tuning. This model has been claimed to be related to self-organized criticality, and its critical properties have been conjectured to be related to directed percolation. Instead, we show that this is a (quasi) neutral model, analogous to those used in Population Genetics and Ecology, with the same critical behavior as the voter-model, i.e. the theory of accidental pathogens is a (quasi)-neutral theory. This analogy allows us to explain all the system phenomenology, including generic scale invariance and the associated scaling exponents, in a parsimonious and simple way.Comment: 13 pages, 6 figures Accepted for publication in PLoS ONE the text have been modified in orden to improve the figure's resolutio