Persistence, extinction and spatio-temporal synchronization of SIRS cellular automata models

Spatially explicit models have been widely used in today's mathematical ecology and epidemiology to study persistence and extinction of populations as well as their spatial patterns. Here we extend the earlier work--static dispersal between neighbouring individuals to mobility of individuals as well as multi-patches environment. As is commonly found, the basic reproductive ratio is maximized for the evolutionary stable strategy (ESS) on diseases' persistence in mean-field theory. This has important implications, as it implies that for a wide range of parameters that infection rate will tend maximum. This is opposite with present results obtained in spatial explicit models that infection rate is limited by upper bound. We observe the emergence of trade-offs of extinction and persistence on the parameters of the infection period and infection rate and show the extinction time having a linear relationship with respect to system size. We further find that the higher mobility can pronouncedly promote the persistence of spread of epidemics, i.e., the phase transition occurs from extinction domain to persistence domain, and the spirals' wavelength increases as the mobility increasing and ultimately, it will saturate at a certain value. Furthermore, for multi-patches case, we find that the lower coupling strength leads to anti-phase oscillation of infected fraction, while higher coupling strength corresponds to in-phase oscillation.Comment: 12page

Intergenerational Wealth Mobility in Rural Bangladesh

Unique residential history data with retrospective information on parental assets are used to study household wealth mobility in 141 villages in rural Bangladesh. Regression estimates of father-son correlations and analyses of intergenerational transition matrices show substantial persistence in wealth even when we correct for measurement errors in parental wealth. We do not find wealth mobility to be higher between periods of a person's life than between generations. We find that the process of household division plays an important role: sons who splinter off from the father's household experience greater (albeit downward) mobility in wealth. Despite significant occupational mobility across generations, its contribution to wealth mobility, net of human capital attainment of individuals, appears insignificant. Low wealth mobility in our data is primarily explained by intergenerational persistence in educational attainment.intergenerational inequality, household wealth, occupational mobility, schooling mobility, transition matrix, Bangladesh

Accounting for Intergenerational Income Persistence: Noncognitive Skills, Ability and Education

We analyse in detail the factors that lead to intergenerational persistence among sons, where this is measured as the association between childhood family income and later adult earnings. We seek to account for the level of income persistence in the 1970 BCS cohort and also to explore the decline in mobility in the UK between the 1958 NCDS cohort and the 1970 cohort. The mediating factors considered are cognitive skills, noncognitive traits, educational attainment and labour market attachment. Changes in the relationships between these variables, parental income and earnings are able to explain over 80% of the rise in intergenerational persistence across the cohorts.intergenerational mobility, children, skills

Accounting for Intergenerational Income Persistence: Non-Cognitive Skills, Ability and Education

We analyse in detail the factors that lead to intergenerational persistence among sons, where this is measured as the association between childhood family income and later adult earnings. We seek to account for the level of income persistence in the 1970 BCS cohort and also to explore the decline in mobility in the UK between the 1958 NCDS cohort and the 1970 cohort. The mediating factors considered are cognitive skills, noncognitive traits, educational attainment and labour market attachment. Changes in the relationships between these variables, parental income and earnings are able to explain over 80% of the rise in intergenerational persistence across the cohorts.Intergenerational mobility, children, skills

American exceptionalism in a new light : a comparison of intergenerational earnings mobility in the Nordic countries, the United Kingdom and the United States

We develop methods and employ similar sample restrictions to analyse differences in intergenerational earnings mobility across the United States, the United Kingdom, Denmark, Finland, Norway and Sweden. We examine earnings mobility among pairs of fathers and sons as well as fathers and daughters using both mobility matrices and regression and correlation coefficients. Our results suggest that all countries exhibit substantial earnings persistence across generations, but with statistically significant differences across countries. Mobility is lower in the U.S. than in the U.K., where it is lower again compared to the Nordic countries. Persistence is greatest in the tails of the distributions and tends to be particularly high in the upper tails: though in the U.S. this is reversed with a particularly high likelihood that sons of the poorest fathers will remain in the lowest earnings quintile. This is a challenge to the popular notion of ’American exceptionalism’. The U.S. also differs from the Nordic countries in its very low likelihood that sons of the highest earners will show downward ’long-distance’ mobility into the lowest earnings quintile. In this, the U.K. is more similar to the U.S

Human mobility networks and persistence of rapidly mutating pathogens

Rapidly mutating pathogens may be able to persist in the population and reach an endemic equilibrium by escaping hosts' acquired immunity. For such diseases, multiple biological, environmental and population-level mechanisms determine the dynamics of the outbreak, including pathogen's epidemiological traits (e.g. transmissibility, infectious period and duration of immunity), seasonality, interaction with other circulating strains and hosts' mixing and spatial fragmentation. Here, we study a susceptible-infected-recovered-susceptible model on a metapopulation where individuals are distributed in subpopulations connected via a network of mobility flows. Through extensive numerical simulations, we explore the phase space of pathogen's persistence and map the dynamical regimes of the pathogen following emergence. Our results show that spatial fragmentation and mobility play a key role in the persistence of the disease whose maximum is reached at intermediate mobility values. We describe the occurrence of different phenomena including local extinction and emergence of epidemic waves, and assess the conditions for large scale spreading. Findings are highlighted in reference to previous works and to real scenarios. Our work uncovers the crucial role of hosts' mobility on the ecological dynamics of rapidly mutating pathogens, opening the path for further studies on disease ecology in the presence of a complex and heterogeneous environment.Comment: 29 pages, 7 figures. Submitted for publicatio

American exceptionalism in a new light : a comparison of intergenerational earnings mobility in the Nordic countries, the United Kingdom and the United States

We develop methods and employ similar sample restrictions to analyse differences in intergenerational earnings mobility across the United States, the United Kingdom, Denmark, Finland, Norway and Sweden. We examine earnings mobility among pairs of fathers and sons as well as fathers and daughters using both mobility matrices and regression and correlation coefficients. Our results suggest that all countries exhibit substantial earnings persistence across generations, but with statistically significant differences across countries. Mobility is lower in the U.S. than in the U.K., where it is lower again compared to the Nordic countries. Persistence is greatest in the tails of the distributions and tends to be particularly high in the upper tails: though in the U.S. this is reversed with a particularly high likelihood that sons of the poorest fathers will remain in the lowest earnings quintile. This is a challenge to the popular notion of ’American exceptionalism’. The U.S. also differs from the Nordic countries in its very low likelihood that sons of the highest earners will show downward ’long-distance’ mobility into the lowest earnings quintile. In this, the U.K. is more similar to the U.S..Intergenerational mobility ; earnings inequality ; long-run earnings

Re-examining inequality persistence

Although it is not a new phenomenon, in recent years inequality has moved to the top of the political agenda given the concern that will result in political instability and social resentment. Persistence in inequality can further undermine economic growth and development by hindering educational opportunities, human capital formation, and intergenerational mobility. The persistent nature of inequality stands as one of the most serious challenges for the global economy. This paper analyses inequality persistence for a sample of 60 countries from 1984 to 2015. The authors conclude that inequality is persistent and government redistribution polices through taxes and transfers did not significantly reduce inequality persistence