Epidemic processes in complex networks

In recent years the research community has accumulated overwhelming evidence for the emergence of complex and heterogeneous connectivity patterns in a wide range of biological and sociotechnical systems. The complex properties of real-world networks have a profound impact on the behavior of equilibrium and nonequilibrium phenomena occurring in various systems, and the study of epidemic spreading is central to our understanding of the unfolding of dynamical processes in complex networks. The theoretical analysis of epidemic spreading in heterogeneous networks requires the development of novel analytical frameworks, and it has produced results of conceptual and practical relevance. A coherent and comprehensive review of the vast research activity concerning epidemic processes is presented, detailing the successful theoretical approaches as well as making their limits and assumptions clear. Physicists, mathematicians, epidemiologists, computer, and social scientists share a common interest in studying epidemic spreading and rely on similar models for the description of the diffusion of pathogens, knowledge, and innovation. For this reason, while focusing on the main results and the paradigmatic models in infectious disease modeling, the major results concerning generalized social contagion processes are also presented. Finally, the research activity at the forefront in the study of epidemic spreading in coevolving, coupled, and time-varying networks is reported.Comment: 62 pages, 15 figures, final versio

Effects of Artichoke (Cynara scolymus L.) Leaf Meal and Vitamin E on Productive Performance, Intestinal Microflora and Morphology in Japanese Quail

A total of 240, one-day-old quail chicks (Coturnix coturnix japonica) were used to study the effects of Artichoke leaf meal (ALM) and vitamin E in diet on growth performance, ileal microbial populations and intestinal morphology in a 42-d trial. This experiment was performed as a completely randomized design with 4 replicates of 15 quails each, using a 4 × 2 factorial arrangement with diet and gender as the main effects. Four dietary treatments were formulated by addition of 2 levels (1.5 and 3 percent) of ALM and 300 mg/Kg vitamin E to the basal diet. Supplementing basal diet with ALM did not improve growth performance at different rearing periods, whereas dietary vitamin E increased feed intake and body weight gain at day 21 of age (P). The ileal populations of lactobacillus and coliforms was not affected by dietary ALM treatments, whereas vitamin E increased the population of total aerobic bacteria (P≤0.04). The ileal villus height (P≤0.01) and crypt depth (P≤0.008) were reduced in quails fed on diets with ALM and vitamin E. The quails fed diets containing 3 percent ALM and 300 mg/Kg vitamin E had higher villus height:crypt depth ratio. The thickness of muscularies (P≤0.04) and mucosa (P≤0.0007) layers were decreased in birds fed diets containing ALM than control birds. Birds treated with ALM and vitamin E showed a shorter intestinal length (P≤0.02) and a lower pancereas relative weight. The results of this study showed that supplementing diet by ALM (1.5 and 3%) and 300 mg/Kg vitamin E did not improve growth performance, ileal microbiota pupolations and intestinal morphometric indices in Japanese quail

Fauna and larval habitats characteristics of mosquitoes (diptera: Culicidae) in Golestan Province, Northeast of Iran, 2014-2015

Background: Mosquitoes (Diptera: Culicidae) is one of the most medically important families of Diptera. The aims of this study were to determine fauna and larval habitat characteristics of mosquitoes in Golestan Province, during 2014-15. Methods: This study was conducted in larval habitats of mosquitoes and installed ovitraps in 14 districts of Golestan Province, Northern Iran in 2015. Samples were collected with a scoop by ladle handling for entomology. The collected larvae were transferred to Laboratory of Medical Entomology in lactophenol solution. Then microscopic slides were prepared using de Faure's formula. Species of each sample was recognized using diagnostic criteria to identify the Culicidae species. Characteristics of larval breeding places were studied based on the habitat type (Permanent or temporary), water conditions (Clear or turbid, stagnant or running), vegetation (out, in, underwater vegetation or without vegetation), sunlight exposure (Full or partial sunlight) and so on. Data were analyzed using SPSS. Results: Overall, 5661 third-and fourth-instars larvae of mosquitoes were collected and 5 genera and 14 species were identified: Anopheles hyrcanus, An. maculipennis, An. pseudopictus, An. superpictus, Culex hortensis, Cx. mimiticus, Cx. perexiguus, Cx. pipiens, Cx. pusillus, Cx. theileri, Cx. tritaeniohynchus, Culiseta longiareolata, Ochlerotatus caspius, Uranotaenia unguiculata. Culex pipiens was recognized as predominant species of the family. Among the detected species, Cx. pusillus reported for the first time from Golestan Province. Conclusion: Due to the high species diversity of Culicidae, ecology of medical important species such as Cx. pipiens and Cx. tritaeniorhynchus needs more investigations. © 2018 Tehran University of Medical Sciences. All rights reserved

Effect of the interconnected network structure on the epidemic threshold

Most real-world networks are not isolated. In order to function fully, they are interconnected with other networks, and this interconnection influences their dynamic processes. For example, when the spread of a disease involves two species, the dynamics of the spread within each species (the contact network) differs from that of the spread between the two species (the interconnected network). We model two generic interconnected networks using two adjacency matrices, A and B, in which A is a 2N×2N matrix that depicts the connectivity within each of two networks of size N, and B a 2N×2N matrix that depicts the interconnections between the two. Using an N-intertwined mean-field approximation, we determine that a critical susceptible-infected-susceptible (SIS) epidemic threshold in two interconnected networks is 1/?1(A+?B), where the infection rate is ? within each of the two individual networks and ?? in the interconnected links between the two networks and ?1(A+?B) is the largest eigenvalue of the matrix A+?B. In order to determine how the epidemic threshold is dependent upon the structure of interconnected networks, we analytically derive ?1(A+?B) using a perturbation approximation for small and large ?, the lower and upper bound for any ? as a function of the adjacency matrix of the two individual networks, and the interconnections between the two and their largest eigenvalues and eigenvectors. We verify these approximation and boundary values for ?1(A+?B) using numerical simulations, and determine how component network features affect ?1(A+?B). We note that, given two isolated networks G1 and G2 with principal eigenvectors x and y, respectively, ?1(A+?B) tends to be higher when nodes i and j with a higher eigenvector component product xiyj are interconnected. This finding suggests essential insights into ways of designing interconnected networks to be robust against epidemics.Intelligent SystemsElectrical Engineering, Mathematics and Computer Scienc