13,432 research outputs found
Process and Progress: Reviewing the Criminal Justice Act
Prado describes the results of a comprehensive study of the federal defender program and concludes that as the federal criminal justice system evolves, the Criminal Justice Act program must adapt to ever-changing conditions
Mozambique and natural disasters: human capital under threat
This paper assesses the effect of a sequence of natural disasters on childrenâs health that hit Mozambique at the start of the 21st Century. The disasters in question were the floods of 2000 and the droughts of the years 2002 and 2003. Height-for-age z-scores of children between 1 and 3 years old is used to capture the cumulative effects of this sequence of natural disasters. It was found that the effect of the disasters on these childrenâs height was, on average, -0.4236 standard deviations, which corresponds to the affected children being more than 1.5 cm shorter by the time of the survey. The findings in this paper are important because of the long term economic cost associated with the disasters, and urge the need for further public intervention to mitigate the damage caused by the shocks. This paper also contributes to the existing literature on the subject of the impact of shocks on child health in the developing world by focusing on measurement errors, differences in physical stature among ethnic groups and migratory movements.Mozambique; Health; Natural Disaster; Human Capital; Developing Country
Connections between the Sznajd Model with General Confidence Rules and graph theory
The Sznajd model is a sociophysics model, that is used to model opinion
propagation and consensus formation in societies. Its main feature is that its
rules favour bigger groups of agreeing people. In a previous work, we
generalized the bounded confidence rule in order to model biases and prejudices
in discrete opinion models. In that work, we applied this modification to the
Sznajd model and presented some preliminary results. The present work extends
what we did in that paper. We present results linking many of the properties of
the mean-field fixed points, with only a few qualitative aspects of the
confidence rule (the biases and prejudices modelled), finding an interesting
connection with graph theory problems. More precisely, we link the existence of
fixed points with the notion of strongly connected graphs and the stability of
fixed points with the problem of finding the maximal independent sets of a
graph. We present some graph theory concepts, together with examples, and
comparisons between the mean-field and simulations in Barab\'asi-Albert
networks, followed by the main mathematical ideas and appendices with the
rigorous proofs of our claims. We also show that there is no qualitative
difference in the mean-field results if we require that a group of size q>2,
instead of a pair, of agreeing agents be formed before they attempt to convince
other sites (for the mean-field, this would coincide with the q-voter model).Comment: 15 pages, 18 figures. To be submitted to Physical Revie
A Generalized Sznajd Model
In the last decade the Sznajd Model has been successfully employed in
modeling some properties and scale features of both proportional and majority
elections. We propose a new version of the Sznajd model with a generalized
bounded confidence rule - a rule that limits the convincing capability of
agents and that is essential to allow coexistence of opinions in the stationary
state. With an appropriate choice of parameters it can be reduced to previous
models. We solved this new model both in a mean-field approach (for an
arbitrary number of opinions) and numerically in a Barabasi-Albert network (for
three and four opinions), studying the transient and the possible stationary
states. We built the phase portrait for the special cases of three and four
opinions, defining the attractors and their basins of attraction. Through this
analysis, we were able to understand and explain discrepancies between
mean-field and simulation results obtained in previous works for the usual
Sznajd Model with bounded confidence and three opinions. Both the dynamical
system approach and our generalized bounded confidence rule are quite general
and we think it can be useful to the understanding of other similar models.Comment: 19 pages with 8 figures. Submitted to Physical Review
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