257 research outputs found
An OLG model of growth with longevity : when grandparents take care of grandchildren
By assuming that grandparents take care of grandchildren, this paper aims at studying the effects of longevity on long-term economic growth in a model with overlapping generations and endogenous fertility. We show that an increase in longevity may: (i) reduce the long-term economic growth; (ii) increase the supply of labour, and (iii) cause fertility either to increase of decrease depending on the size of time spent by grandparents to rise grandchildren. These findings also hold in an endogenous growth setting a` la Romer (J Polit Econ 94:1002–1037, 1986).info:eu-repo/semantics/publishedVersio
Boolean Dynamics with Random Couplings
This paper reviews a class of generic dissipative dynamical systems called
N-K models. In these models, the dynamics of N elements, defined as Boolean
variables, develop step by step, clocked by a discrete time variable. Each of
the N Boolean elements at a given time is given a value which depends upon K
elements in the previous time step.
We review the work of many authors on the behavior of the models, looking
particularly at the structure and lengths of their cycles, the sizes of their
basins of attraction, and the flow of information through the systems. In the
limit of infinite N, there is a phase transition between a chaotic and an
ordered phase, with a critical phase in between.
We argue that the behavior of this system depends significantly on the
topology of the network connections. If the elements are placed upon a lattice
with dimension d, the system shows correlations related to the standard
percolation or directed percolation phase transition on such a lattice. On the
other hand, a very different behavior is seen in the Kauffman net in which all
spins are equally likely to be coupled to a given spin. In this situation,
coupling loops are mostly suppressed, and the behavior of the system is much
more like that of a mean field theory.
We also describe possible applications of the models to, for example, genetic
networks, cell differentiation, evolution, democracy in social systems and
neural networks.Comment: 69 pages, 16 figures, Submitted to Springer Applied Mathematical
Sciences Serie
Towards an optimal therapy strategy for myogenous TMD, physiotherapy compared with occlusal splint therapy in an RCT with therapy-and-patient-specific treatment durations
Appendix. Threshold of signs and symptoms. Post-hoc power analysis on measures of effectiveness. Two-way ANOVA statistical analysis for pain intensity. Rules for progressing and ending splint therapy. Rules for progressing and ending physiotherapy. A stepped-care model including two possible therapies. (PDF 86Â kb
The impacts of Information and Communications Technology (ICT) and E-commerce on bilateral trade flows
This study examines the impact of Internet and e-commerce adoption on bilateral trade flows using a panel of 21 developing- and least-developed countries and 30 OECD countries. Given the commitment of East African Community (EAC) to become the frontrunner in export-led economy across the African continent, special attention is dedicated to analyse the role of ICT and e-commerce on EAC’s export performance. The empirical results indicate that better access to the modern ICT and adoption of e-commerce applications stimulate bilateral trade flows at various levels. The study notes that the efficient use of ICT equipped with high speed internet and secured servers is a crucial milestone for unlocking the e-trade potentials for developing- and least-developed counties
Respiração bucal e anteriorização da cabeça: efeitos na biomecânica respiratĂłria e na capacidade de exercĂcio em crianças
Long-Term Climate Forcing in Loggerhead Sea Turtle Nesting
The long-term variability of marine turtle populations remains poorly understood,
limiting science and management. Here we use basin-scale climate indices and
regional surface temperatures to estimate loggerhead sea turtle (Caretta
caretta) nesting at a variety of spatial and temporal scales.
Borrowing from fisheries research, our models investigate how oceanographic
processes influence juvenile recruitment and regulate population dynamics. This
novel approach finds local populations in the North Pacific and Northwest
Atlantic are regionally synchronized and strongly correlated to ocean
conditions—such that climate models alone explain up to 88% of the
observed changes over the past several decades. In addition to its performance,
climate-based modeling also provides mechanistic forecasts of historical and
future population changes. Hindcasts in both regions indicate climatic
conditions may have been a factor in recent declines, but future forecasts are
mixed. Available climatic data suggests the Pacific population will be
significantly reduced by 2040, but indicates the Atlantic population may
increase substantially. These results do not exonerate anthropogenic impacts,
but highlight the significance of bottom-up oceanographic processes to marine
organisms. Future studies should consider environmental baselines in assessments
of marine turtle population variability and persistence
Agriculture, transportation and the timing of urbanization: Global analysis at the grid cell level
The human capital transition and the role of policy
Along with information and communication technology, infrastructure, and the innovation system, human capital is a key pillar of the knowledge economy with its scope for increasing returns. With this in mind, the purpose of this chapter is to investigate how industrialized economies managed to achieve the transition from low to high levels of human capital. The first phase of the human capital transition was the result of the interaction of supply and demand, triggered by technological change and boosted by the demands for (immaterial) services. The second phase of the human capital transition (i.e., mass education) resulted from enforced legislation and major public investment. The state’s aim to influence children’s beliefs appears to have been a key driver in public investment. Nevertheless, the roles governments played differed according to the developmental status and inherent socioeconomic and political characteristics of their countries. These features of the human capital transition highlight the importance of understanding governments’ incentives and roles in transitions
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