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In this paper we build a network-based model to evaluate and compare vaccination plans in order to find the optimal strategies. The age-structured model is designed to take into account the comorbidity status and vaccination hesitancy of the population. The network-based model is calibrated to reported infected cases and deaths in the USA in order to obtain an approximated realistic scenario to test the vaccination strategies. We adapt an algorithm that is based on Bayesian optimization over permutation spaces with heuristics in order to deal with the discrete space of the vaccination strategies. We also developed an ad-hoc randomized algorithm which has a higher computational cost. Both algorithms provide similar patterns of the best found vaccination strategies. We find that these best vaccination plans prioritize the age-groups 40–59 and 60–69 years old, both with comorbidities. This result shows the highly nonlinear complexity related to the problem and its dependence on social contacts and case fatality rates. The developed network-based model adapts well to the uncertainty and heterogeneity of the real world situation and allows us to assess the efficacy of many vaccination strategies. The stochastic nature of the simulations enables us to explore additional potential scenarios and the findings offer useful information for developing vaccination plans for other future potential pandemics.

[EN] Recently, the transmission dynamics of the Human Papillomavirus (HPV) has been studied. In previous works, we have designed and implemented a computational model (agent-based simulation model) where the contagion of the HPV is described on a network of lifetime sexual partners. The run of a single simulation of this computational model, composed of a network with 500 000 nodes, takes about one hour and a half. In addition to set an adequate model, finding out the model parameters that best fit the proposed model to the available data of prevalence is a crucial goal. Taking into account that the necessary number of simulations to perform the calibration of the model may be very high, the aforementioned goal may become unaffordable. In this paper, we present a procedure to fit the proposed HPV model to the available data and the design of an asynchronous version of the Particle Swarm Optimization (PSO) algorithm adapted to the distributed computing environment. In the process, the number of particles used in PSO should be set carefully looking for a compromise between quality of the solutions and computation time. Another feature of the procedure presented here is that we want to capture the intrinsic uncertainty in the data (data come from a survey) when calibrating the model. To do so, we also propose the design of an algorithm to select the model parameter sets obtained during the calibration that best capture the data uncertainty.

[EN] Working in large networks applied to epidemiological-type models has led us to design a simple but e↵ective computed distributed environment to perform a large amount of model simulations in a reasonable time in order to study the behavior of these models and to calibrate them. Finding the model parameters that best fit the available data in the designed distributed computing environment becomes a challenge and it is necessary to implement reliable algorithms for model calibration. In this paper, we have adapted the random PSO algorithm to our distributed computing environment to be applied to the calibration of a Papillomavirus transmission dynamics model on a lifetime sexual partners network. And we have obtained a good fitting saving time and calculations compared with the exhaustive searching strategy we have been using so far.

[EN] The Human papillomaviruses (HPV) vaccine induces a herd immunity effect in genital warts when a large number of the population is vaccinated. This aspect should be taken into account when devising new vaccine strategies, like vaccination at older ages or male vaccination. Therefore, it is important to develop mathematical models with good predictive capacities. We devised a sexual contact network that was calibrated to simulate the Spanish epidemiology of different HPV genotypes. Through this model, we simulated the scenario that occurred in Australia in 2007, where 12¿13 year-old girls were vaccinated with a three-dose schedule of a vaccine containing genotypes 6 and 11, which protect against genital warts, and also a catch-up program in women up to 26 years of age. Vaccine coverage were 73% in girls with three doses and with coverage rates decreasing with age until 52% for 20¿26 year-olds. A fast 59% reduction in the genital warts diagnoses occurred in the model in the first years after the start of the program, similar to what was described in the literature.

We present experimental and theoretical results on single- and multiple-electron capture, and fragmentation, in C6+ + C-60 collisions at velocities in the v(col) = 0.05 - 0.4 a.u. range. We use time-of-flight mass spectrometry and coincidence detection of charged fragments to separate pure target ionization from processes in which the C-60 target is both ionized and fragmented. The coincidence technique allows us to identify different types of fragmentation processes such as C-60(q+) -> C-58(q+) + C-2 and C-60(q+) -> C-58((q-1)+) + C-2(+). A quasimolecular approach is employed to calculate charge transfer and target excitation cross sections. First-order time-dependent perturbation and statistical methods are used to treat the postcollisional processes: the calculated rate constants for C-2 and C-2(+) emission from the excited and charged fullerene are then used to evaluate the fragmentation dynamics. We show that the target ionization cross section decreases with the induced target charge state and the impact energy. C-2 emission from C-60(q+) is found to dominate when q <= 2 while C-2(+) emission dominates when q >= 5, in agreement with the present and previous experimental results., AuthorCount:13

© 2014 Pérez-Breva et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated., Background: Meningococcal C (MenC) conjugate vaccines have controlled invasive diseases associated with this serogroup in countries where they are included in National Immunization Programs and also in an extensive catch-up program involving subjects up to 20 years of age. Catch-up was important, not only because it prevented disease in adolescents and young adults at risk, but also because it decreased transmission of the bacteria, since it was in this age group where the organism was circulating. Our objective is to develop a new vaccination schedule to achieve maximum seroprotection in these groups. Methods: A recent study has provided detailed age-structured information on the seroprotection levels against MenC in Valencia (Spain), where vaccination is routinely scheduled at 2 months and 6 months, with a booster dose at 18 months of age. A complementary catch-up campaign was also carried out in n for children from 12 months to 19 years of age. Statistical analyses of these data have provided an accurate picture on the evolution of seroprotection in the last few years. Results: An agent-based model has been developed to study the future evolution of the seroprotection histogram. We have shown that the optimum strategy for achieving high protection levels in all infants, toddlers and adolescents is a change to a 2 months, 12 months and 12 years of age vaccination pattern. If the new schedule were implemented in January 2014, high-risk subjects between 15-19 years of age would have very low seroprotection for the next 6 years, thereby threatening the program. Conclusions: High protection levels and a low incidence of meningococcal C disease can be achieved in the future by means of a cost-free change in vaccination program. However, we recommend a new catch-up program simultaneous to the change in regular vaccination program

A Sitges, pràcticament tot el tràfic intern es veu obligat a passar per la cruïlla del Pg. de Vilafranca, fet que es complica més si s’analitza l’efecte barrera que el Nucli Antic té en el viari. Els diferents accessos principals recullen viatges que poden ser de les mateixes zones exteriors i es fa difícil caracteritzar l’origen dels viatges externs a la població per accés ja que aquests depenen més aviat del seu destí. Cal dir també l’efecte barrera que suposa el pas de la via de tren al nord de la població i superat en quatre punts pel vial. Aquests dos fets afegits a la presència del mar caracteritzen la trama urbana de la població. La proposta que es formula és la d’una nova xarxa de transport urbà, passant, que comuniqui les diferentes zones d’una i altra banda de la població sense la necessitat de fer transbord. Aquesta nova xarxa constaria de tres línees i entre elles arribarien a totes les urbanitzacions perimetrals de Sitges. La principal proposta referent a transport interurbà és la d’execució d’una nova estació de Renfe al sector del Vinyet i Cases del Sord. Tenint en compte que el radi d’atracció d’una estació de tren és de 1.000 metres, al plànol nº 11 s’observa un abarcament semitotal de la trama urbana. Aquesta nova estació ferroviària estaria complementada amb un aparcament de vehicles tipus Park & Ride per fomentar el transport intermodal. Per últim, proposar també l’ordenació de l’actual Estació de Renfe al centre del poble donada la quantitat de motos i bicicletes que obstruexen el pas dels viatgers al surtir de l’Estació.