10,513 research outputs found
Failure-recovery model with competition between failures in complex networks: a dynamical approach
Real systems are usually composed by units or nodes whose activity can be
interrupted and restored intermittently due to complex interactions not only
with the environment, but also with the same system. Majdand\v{z}i\'c
[Nature Physics 10, 34 (2014)] proposed a model to study systems in which
active nodes fail and recover spontaneously in a complex network and found that
in the steady state the density of active nodes can exhibit an abrupt
transition and hysteresis depending on the values of the parameters. Here we
investigate a model of recovery-failure from a dynamical point of view. Using
an effective degree approach we find that the systems can exhibit a temporal
sharp decrease in the fraction of active nodes. Moreover we show that,
depending on the values of the parameters, the fraction of active nodes has an
oscillatory regime which we explain as a competition between different failure
processes. We also find that in the non-oscillatory regime, the critical
fraction of active nodes presents a discontinuous drop which can be related to
a "targeted" k-core percolation process. Finally, using mean field equations we
analyze the space of parameters at which hysteresis and oscillatory regimes can
be found
Social distancing strategies against disease spreading
The recurrent infectious diseases and their increasing impact on the society
has promoted the study of strategies to slow down the epidemic spreading. In
this review we outline the applications of percolation theory to describe
strategies against epidemic spreading on complex networks. We give a general
outlook of the relation between link percolation and the
susceptible-infected-recovered model, and introduce the node void percolation
process to describe the dilution of the network composed by healthy individual,
, the network that sustain the functionality of a society. Then, we survey
two strategies: the quenched disorder strategy where an heterogeneous
distribution of contact intensities is induced in society, and the intermittent
social distancing strategy where health individuals are persuaded to avoid
contact with their neighbors for intermittent periods of time. Using
percolation tools, we show that both strategies may halt the epidemic
spreading. Finally, we discuss the role of the transmissibility, , the
effective probability to transmit a disease, on the performance of the
strategies to slow down the epidemic spreading.Comment: to be published in "Perspectives and Challenges in Statistical
Physics and Complex Systems for the Next Decade", Word Scientific Pres
Predicting the extinction of Ebola spreading in Liberia due to mitigation strategies
The Ebola virus is spreading throughout West Africa and is causing thousands
of deaths. In order to quantify the effectiveness of different strategies for
controlling the spread, we develop a mathematical model in which the
propagation of the Ebola virus through Liberia is caused by travel between
counties. For the initial months in which the Ebola virus spreads, we find that
the arrival times of the disease into the counties predicted by our model are
compatible with World Health Organization data, but we also find that reducing
mobility is insufficient to contain the epidemic because it delays the arrival
of Ebola virus in each county by only a few weeks. We study the effect of a
strategy in which safe burials are increased and effective hospitalisation
instituted under two scenarios: (i) one implemented in mid-July 2014 and (ii)
one in mid-August---which was the actual time that strong interventions began
in Liberia. We find that if scenario (i) had been pursued the lifetime of the
epidemic would have been three months shorter and the total number of infected
individuals 80\% less than in scenario (ii). Our projection under scenario (ii)
is that the spreading will stop by mid-spring 2015
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