scholarly journals Transient prophylaxis and multiple epidemic waves

2022 ◽  
Vol 7 (4) ◽  
pp. 5616-5633
Author(s):  
Rebecca C. Tyson ◽  
◽  
Noah D. Marshall ◽  
Bert O. Baumgaertner ◽  
◽  
...  

<abstract><p>Public opinion and opinion dynamics can have a strong effect on the transmission rate of an infectious disease for which there is no vaccine. The coupling of disease and opinion dynamics however, creates a dynamical system that is complex and poorly understood. We present a simple model in which susceptible groups adopt or give up prophylactic behaviour in accordance with the influence related to pro- and con-prophylactic communication. This influence varies with disease prevalence. We observe how the speed of the opinion dynamics affects the total size and peak size of the epidemic. We find that more reactive populations will experience a lower peak epidemic size, but possibly a larger final size and more epidemic waves, and that an increase in polarization results in a larger epidemic.</p></abstract>

2009 ◽  
Vol 2009 ◽  
pp. 1-7 ◽  
Author(s):  
Dejun Fan ◽  
Ke Wang ◽  
Ling Hong

A simple model of the dynamics of an infectious disease, taking into account environmental variability in the form of Gaussian white noise in the disease transmission rate and the increase in mortality rate due to disease, has been investigated. The probability distribution for the proportion of infected animals, plus its mean, mode, and variance, is found explicitly.


2012 ◽  
Vol 54 (1-2) ◽  
pp. 23-36 ◽  
Author(s):  
E. K. WATERS ◽  
H. S. SIDHU ◽  
G. N. MERCER

AbstractPatchy or divided populations can be important to infectious disease transmission. We first show that Lloyd’s mean crowding index, an index of patchiness from ecology, appears as a term in simple deterministic epidemic models of the SIR type. Using these models, we demonstrate that the rate of movement between patches is crucial for epidemic dynamics. In particular, there is a relationship between epidemic final size and epidemic duration in patchy habitats: controlling inter-patch movement will reduce epidemic duration, but also final size. This suggests that a strategy of quarantining infected areas during the initial phases of a virulent epidemic might reduce epidemic duration, but leave the population vulnerable to future epidemics by inhibiting the development of herd immunity.


2021 ◽  
Vol 9 ◽  
Author(s):  
Longzhao Liu ◽  
Xin Wang ◽  
Xuyang Chen ◽  
Shaoting Tang ◽  
Zhiming Zheng

Confirmation bias and peer pressure are regarded as the main psychology origins of personal opinion adjustment. Each show substantial impacts on the formation of collective decisions. Nevertheless, few attempts have been made to study how the interplay between these two mechanisms affects public opinion evolution on large-scale social networks. In this paper, we propose an agent-based model of opinion dynamics which incorporates the conjugate effect of confirmation bias (characterized by the population identity scope and initiative adaptation speed) and peer pressure (described by a susceptibility threshold and passive adaptation speed). First, a counterintuitive non-monotonous phenomenon arises in the homogeneous population: the number of opinion clusters first increases and then decreases to one as the population identity scope becomes larger. We then consider heterogeneous populations where “impressionable” individuals with large susceptibility to peer pressure and “confident” individuals with small susceptibility coexist. We find that even a small fraction of impressionable individuals could help eliminate public polarization when population identity scope is relatively large. In particular, the impact of impressionable agents would be greater if these agents are hubs. More intriguingly, while impressionable individuals have randomly distributed initial opinions, most of them would finally evolve to moderates. We highlight the emergence of these “impressionable moderates” who are easily influenced, yet are important in public opinion competition, which may inspire efficient strategies in winning competitive campaigns.


Complexity ◽  
2009 ◽  
Vol 15 (2) ◽  
pp. 54-63 ◽  
Author(s):  
Gani Aldashev ◽  
Timoteo Carletti

Author(s):  
Levi Njord ◽  
Ray Μ Merrill ◽  
Rebecca Njord ◽  
Jeanette DR Pachano ◽  
Austin Hackett

Author(s):  
Douglas Foyle

Dramatic changes in the way the public acquires information and formulates its attitudes have potentially altered the opinion and foreign policy relationship. While traditional approaches have treated public opinion on domestic and foreign matters as largely distinct, the culmination of a series of changes may eliminate the effective distinction between foreign and domestic policy, at least in terms of how the American political system operates. All the factors central to the opinion and foreign policy process, such as information acquisition, attitude formation, media effects, the effect of opinion on policy, and presidential leadership now appear to mirror the processes observed at the domestic level. This analysis reviews historical trends in the literature on public opinion and foreign policy that has focused on the rationality of the public’s opinions, the structure of its attitudes, and its influence on foreign policymaking. The traditional Almond-Lippmann consensus portrayed an emotional public with unstructured attitudes and little influence on foreign policy; however, revisionist views have described a reasonable public with largely structured views on foreign policy that can, at times, constrain and even drive those policies. More recently, the rise of “intermestic” issues, contain both domestic and international elements, such as globalization, inequality, terrorism, immigration, and climate change, have interacted to transform the domestic and international context. The bulk of this analysis highlights emerging new research directions that should be pursued in light of the changes. First, scholars should continue to evaluate the “who thinks what and why” questions with particular attention to differences between high- and low-information individuals, the effect of misinformation, and information sources. In doing so, research should build on research from non-American contexts that points to the important influences of societal and institutional factors. In addition to continued examination of traditional demographic factors such as partisanship and ideology, additional attention should turn to consider potential genetic and biological foundations of attitudes. Finally, researchers should continue to evaluate how the new media environment, including social media, affects how the public accesses information, how the media provides information, and how political elites attempt to shape both. Given these changes, scholars should consider whether it continues to make sense to treat public opinion dynamics regarding foreign policy as distinct from domestic policy and its implications.


2011 ◽  
Vol 48 (A) ◽  
pp. 235-247
Author(s):  
Daryl J. Daley ◽  
Randall J. Swift

Based on a simple model due to Dietz, it is shown that the size of a major epidemic of a vector-borne disease with basic reproduction ratio R 0&gt;1 is dominated by the size of a standard SIR (susceptible–infected–removed) epidemic with direct host-to-host transmission of disease and the same R 0. Further bounds and numerical illustrations are provided, broadly spanning situations where the size of the epidemic is short of infecting almost all those susceptible. The total size is moderately sensitive to changes in the population parameters that contribute to R 0, so that the fluctuating behaviour in ‘annual’ epidemics is not surprising.


1990 ◽  
Vol 68 (9) ◽  
pp. 1099-1104
Author(s):  
Mark F. Schumaker ◽  
Irving R. Epstein

We develop a simple model for the aggregation of telechelic ionomers by extending the well-known algorithm for particle diffusion-limited aggregation (DLA). The distribution of sticky and nonsticky regions of the polymer and specific rules for binding are incorporated. Thirteen aggregates are grown to a final size of 2441 polymers each. The distribution of accessible binding sites modifies the growth of these clusters as compared with DLA. The dynamical dimension estimated from the growth of the radius of gyration is found to have a value of 1.81 ± 0.04, significantly larger than values reported for particle DLA. However, a careful analysis of our data suggests that the dimension is nonstationary and decreasing at the largest cluster sizes attained. We have also investigated the scaling of the average mass of the cluster interface with the number of polymers and the radius of gyration. Our results suggest that the fractal dimension of the cluster interface is close to one, in agreement with previously reported findings for particle DLA.


2016 ◽  
Vol 57 (4) ◽  
pp. 429-444 ◽  
Author(s):  
K. MCCULLOCH ◽  
M. G. ROBERTS ◽  
C. R. LAING

We investigate the dynamics of a susceptible infected recovered (SIR) epidemic model on small networks with different topologies, as a stepping stone to determining how the structure of a contact network impacts the transmission of infection through a population. For an SIR model on a network of$N$nodes, there are$3^{N}$configurations that the network can be in. To simplify the analysis, we group the states together based on the number of nodes in each infection state and the symmetries of the network. We derive analytical expressions for the final epidemic size of an SIR model on small networks composed of three or four nodes with different topological structures. Differential equations which describe the transition of the network between states are also derived and solved numerically to confirm our analysis. A stochastic SIR model is numerically simulated on each of the small networks with the same initial conditions and infection parameters to confirm our results independently. We show that the structure of the network, degree of the initial infectious node, number of initial infectious nodes and the transmission rate all significantly impact the final epidemic size of an SIR model on small networks.


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