Heterogeneous delays making parents synchronized: A coupled maps on Cayley tree model

We study the phase synchronized clusters in the diffusively coupled maps on the Cayley tree networks for heterogeneous delay values. Cayley tree networks comprise of two parts: the inner nodes and the boundary nodes. We find that heterogeneous delays lead to various cluster states, such as; (a) cluster state consisting of inner nodes and boundary nodes, and (b) cluster state consisting of only boundary nodes. The former state may comprise of nodes from all the generations forming self-organized cluster or nodes from few generations yielding driven clusters depending upon on the parity of heterogeneous delay values. Furthermore, heterogeneity in delays leads to the lag synchronization between the siblings lying on the boundary by destroying the exact synchronization among them. The time lag being equal to the difference in the delay values. The Lyapunov function analysis sheds light on the destruction of the exact synchrony among the last generation nodes. To the end we discuss the relevance of our results with respect to their applications in the family business as well as in understanding the occurrence of genetic diseases.Comment: 9 pages, 11 figure

Transition from the self-organized to the driven dynamical clusters

We study the mechanism of formation of synchronized clusters in coupled maps on networks with various connection architectures. The nodes in a cluster are self- synchronized or driven-synchronized, based on the coupling strength and underlying network structures. A smaller coupling strength region shows driven clusters independent of the network rewiring strategies, whereas a larger coupling strength region shows the transition from the self-organized cluster to the driven cluster as network connections are rewired to the bi-partite type. Lyapunov function analysis is performed to understand the dynamical origin of cluster formation. The results provide insights into the relationship between the topological clusters which are based on the direct connections between the nodes, and the dynamical clusters which are based on the functional behavior of these nodes.Comment: 18 pages, 7 figure

Emergence of (bi)multi-partiteness in networks having inhibitory and excitatory couplings

(Bi)multi-partite interaction patterns are commonly observed in real world systems which have inhibitory and excitatory couplings. We hypothesize these structural interaction pattern to be stable and naturally arising in the course of evolution. We demonstrate that a random structure evolves to the (bi)multi-partite structure by imposing stability criterion through minimization of the largest eigenvalue in the genetic algorithm devised on the interacting units having inhibitory and excitatory couplings. The evolved interaction patterns are robust against changes in the initial network architecture as well as fluctuations in the interaction weights.Comment: 6 pages, 7 figure

Multiplexing induced explosive synchronization in Kuramoto oscillators with inertia

Explosive synchronization (ES) of coupled oscillators on networks is shown to be originated from existence of correlation between natural frequencies of oscillators and degrees of corresponding nodes. Here, we demonstrate that ES is a generic feature of multiplex network of second-order Kuramoto oscillators and can exist in absence of a frequency-degree correlation. A monoplex network of second-order Kuramoto oscillators bearing homogeneous (heterogeneous) degree-distribution is known to display the first-order (second-order) transition to synchronization. We report that multiplexing of two such networks having homogeneous degree-distribution support the first-order transition in both the layers thereby facilitating ES. More interesting is the multiplexing of a layer bearing heterogeneous degree-distribution with another layer bearing homogeneous degree-distribution, which induces a first-order (ES) transition in the heterogeneous layer which was incapable of showing the same in the isolation. Further, we report that such induced ES transition in the heterogeneous layer of multiplex networks can be controlled by varying inter and intra-layer coupling strengths. Our findings emphasize on importance of multiplexing or impact of one layer on dynamical evolution of other layers of systems having inherent multiplex or multilevel architecture.Comment: 7 pages, 10 figure

Spatial poverty traps?

Can place of residence make the difference between growth and contraction in living standards for otherwise identical households? The authors test for the existence of spatial poverty traps, using a micro model of consumption growth incorporating geographic externalities, whereby neighborhood endowments of physical and human capital influence the productivity of a household's own capital. By allowing for nonstationary but unobserved individual effects on growth rates, they are able to deal with latent heterogeneity (whereby hidden factors entail that seemingly identical households see different consumption gains over time), yet identify the effects of stationary geographic variables. They estimate the model using farm-household panel data from post-reform rural China. They find strong evidence of spatial poverty traps. Their results strengthen the case -- both for efficiency and equity -- for investing in the geographic capital of poor people.Environmental Economics&Policies,Economic Theory&Research,Public Health Promotion,Health Monitoring&Evaluation,Economic Conditions and Volatility,Achieving Shared Growth,Economic Theory&Research,Environmental Economics&Policies,Inequality,Health Monitoring&Evaluation

Estimating the Benefit Incidence of an Antipoverty Program by Propensity Score Matching

Income gains from participation in economic programs are estimated as the difference between income with the program and that without it. The "with" data can be collected without much difficulty. But the "without" data are fundamentally unobserved, since an individual cannot be both a participant and a non-participant of the same program. It is common practice to estimate the unobserved income without the program as income with the program minus wages received. However, there are opportunity costs of participating in the program. Ignoring these foregone incomes of participation will result in over-estimation of the gains from the program. We apply recent advances in propensity-score matching methods (PSM) to the problem of estimating the distribution of net income gains from an Argentinean workfare program. PSM allows us to draw a statistical comparison group to workfare participants from a larger contemporaneous and comparable survey of non-participants. The average incomes of the comparison group are compared with the average incomes of the participants to assess the direct income gains from the program. The average gain is found to be about half the gross wage. Over half of the beneficiaries are in the poorest decile nationally, and 80% are in the poorest quintile. Our PSM estimator is reasonably robust to a number of changes in methodology, including a instrumental variables test for selection bias after matching.

Transient poverty in rural China

The authors study transient poverty in a six-year panel dataset for a sample of 5,000 households in post-reform rural China. Half of the mean squared poverty gap is transient, in that it is directly attributable to fluctuations in consumption over time. There is enough transient poverty to treble the cost of eliminating chronic poverty when targeting solely according to current consumption - and to title the balance in favor of untargeted transfers. Transient poverty is low among the chronically poorest, and tends to be high among those near the poverty line. Using censored quantile regression techniques, the authors find that systemic factors determine transient poverty, although they are generally congruent with the determinants of chronic poverty. There is little to suggest that the two types of poverty are created by fundamentally different processes. It appears that the same things that would help reduce chronic poverty - higher and more secure farm yield and higher levels of physical and human capital - would also help reduce transient poverty.Health Economics&Finance,Environmental Economics&Policies,Poverty Reduction Strategies,Services&Transfers to Poor,Poverty Monitoring&Analysis,Safety Nets and Transfers,Services&Transfers to Poor,Poverty Assessment,Poverty Reduction Strategies,Rural Poverty Reduction