105 research outputs found

    Abitare il pianeta. Futuro demografico, migrazioni e tensioni etniche. Volume secondo. USA, URSS e aree asiatiche e australe

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    Le ripercussioni e le conseguenze della pressione demografica esercitata dai Paesi in Via di Sviluppo non riguardano soltanto l'Europa; in altre zone del mondo i problemi dell'integrazione etnica e razziale, delle immigrazioni e dello squili-brio demografico sono altrettanto urgenti: in questo volume vengono ripercorse le linee evolutive ed analizzate le tendenze di alcune societĂ  extra europee, scelte per l'emblematicitĂ  dei casi che rappresentano.- Indice #7- Prima parte Immigrazioni e diversitĂ  etnico-razziali nell'evoluzione demografica degli Stati Uniti d'America #9- Il cambiamento demografico negli Stati Uniti: le tendenze recenti e le prospettive future, Thomas J. Espenshade #11- Immigrazione e diversitĂ  etnico-razziale: il caso degli Stati Uniti, S. Philip Morgan #47- Seconda parte Considerazioni sul mutamento etnico e demografico in Unione Sovietica #69- La popolazione complessiva e per repubbliche dell'Unione Sovietica, Guido Ortona #71- I gruppi etnici in Unione Sovietica, Marco Buttino #91- Terza parte L'evoluzione delle societĂ  multietniche nelle aree asiatica e australe #143- La popolazione indiana, 1951-2021, Enrica Collotti Pischel e Francesco Gallucci #145- DiversitĂ  etnica ed emigrazione: il caso delle migrazioni dal Sud-est asiatico all'Australia, Subbiah Gunasekaran e Gerard Sullivan #215- Il mutamento demografico e lo sviluppo di una societĂ  multiculturale in Australia, Stephen Castles #243- Stime e proiezioni sull'area asiatico-australe, Gian Carlo Blangiardo #289- Quarta parte Alcune considerazioni sui fenomeni complessivi #303- Le grandezze in campo: sulle conseguenze politiche degli scenari demografici mondiali, Piero Gastaldo #30

    Inferring transient dynamics of human populations from matrix non-normality

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    This is the final version of the article. Available from Springer Verlag via the DOI in this record.In our increasingly unstable and unpredictable world, population dynamics rarely settle uniformly to long-term behaviour. However, projecting period-by-period through the preceding fluctuations is more data-intensive and analytically involved than evaluating at equilibrium. To efficiently model populations and best inform policy, we require pragmatic suggestions as to when it is necessary to incorporate short-term transient dynamics and their effect on eventual projected population size. To estimate this need for matrix population modelling, we adopt a linear algebraic quantity known as non-normality. Matrix non-normality is distinct from normality in the Gaussian sense, and indicates the amplificatory potential of the population projection matrix given a particular population vector. In this paper, we compare and contrast three well-regarded metrics of non-normality, which were calculated for over 1000 age-structured human population projection matrices from 42 European countries in the period 1960 to 2014. Non-normality increased over time, mirroring the indices of transient dynamics that peaked around the millennium. By standardising the matrices to focus on transient dynamics and not changes in the asymptotic growth rate, we show that the damping ratio is an uninformative predictor of whether a population is prone to transient booms or busts in its size. These analyses suggest that population ecology approaches to inferring transient dynamics have too often relied on suboptimal analytical tools focussed on an initial population vector rather than the capacity of the life cycle to amplify or dampen transient fluctuations. Finally, we introduce the engineering technique of pseudospectra analysis to population ecology, which, like matrix non-normality, provides a more complete description of the transient fluctuations than the damping ratio. Pseudospectra analysis could further support non-normality assessment to enable a greater understanding of when we might expect transient phases to impact eventual population dynamics.This work was funded by Wellcome Trust New Investigator 103780 to TE, who is also funded by NERC Fellowship NE/J018163/1. JB gratefully acknowledges the ESRC Centre for Population Change ES/K007394/1

    Irregular Migration Theories

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