10,622 research outputs found
News from the Federations...
Last November marked the CHAâs first
formail participation in the administrative
council of the CFH since we joined the
organization last summer. At this meeting,
the CHAâs representative, Jean-Claude
Robert was invited to take part in a new
rite known as âAnnual Lobby Dayâ
Interaction of two systems with saddle-node bifurcations on invariant circles. I. Foundations and the mutualistic case
The saddle-node bifurcation on an invariant circle (SNIC) is one of the
codimension-one routes to creation or destruction of a periodic orbit in a
continuous-time dynamical system. It governs the transition from resting
behaviour to periodic spiking in many class I neurons, for example. Here, as a
first step towards theory of networks of such units the effect of weak coupling
between two systems with a SNIC is analysed. Two crucial parameters of the
coupling are identified, which we call \delta_1 and \delta_2. Global
bifurcation diagrams are obtained here for the "mutualistic" case \delta_1
\delta_2 > 0. According to the parameter regime, there may coexist resting and
periodic attractors, and there can be quasiperiodic attractors of torus or
cantorus type, making the behaviour of even such a simple system quite
non-trivial. In a second paper we will analyse the mixed case \delta_1 \delta_2
< 0 and summarise the conclusions of this study.Comment: 37 pages, 27 figure
THE IMPACT OF CLIMATE CHANGE ON THE PROFITABILITY OF SITE SPECIFIC TECHNOLOGIES
Site Specific Technologies (SST) can reduce environmental pollution caused by common agricultural practice. Using a case study for corn yields, we investigate the impact of climate change (CC) on profitability of SSTs. We find CC to increase spatial variability of soils with respect to optimal input application and yield variability. This leads, ceteris paribus, to higher incentives for SST adoption in the future.Climate Change, Site Specific Technologies, Adaptation, Crop Production Function., Environmental Economics and Policy,
The Impact of Climate Change on the Profitability of Site Specific Technologies
Site Specific Technologies (SST) can reduce environmental pollution caused by common agricultural practice. Using a case study for corn yields, we investigate the impact of climate change (CC) on profitability of SSTs. We find CC to increase spatial variability of soils with respect to optimal input application and yield variability. This leads, ceteris paribus, to higher incentives for SST adoption in the future.Climate Change; Site Specific Technologies; Adaptation; Crop Production Function
Paradoxes in Physical Health
This chapter reviews the evidence from social science and medical research that sheds light on this potential immigrant paradox in health -- when, where, and for whom it holds or does not apply. In doing so, two important points need to be kept in mind. First, the existence of the paradox does not necessarily mean that immigrants are doing than everyone else. Rather, it means that they are doing better than social and economic positions suggest that they should be. Second, paradox may apply in general but not hold in specific domains of health for certain subgroups or at certain life stages. The health literature is so voluminous that it cannot be reviewed in its entirety. Instead, this chapter is more selective in its coverage. In line with the developmental and ecological spirit of this book, a particular health topic has been chosen to highlight what is occurring in major periods of the early life course and to demonstrate how physical, social, and cultural forces and contexts intersect to strengthen or weaken the immigrant paradox around this topic. Specifically, the chapter focuses on infant mortality, childhood illness and disease, and adolescent health behavior, giving additional attention to a topic that cuts across life stages: obesity
Abrupt bifurcations in chaotic scattering : view from the anti-integrable limit
Bleher, Ott and Grebogi found numerically an interesting chaotic phenomenon in 1989 for the scattering of a particle in a plane from a potential field with several peaks of equal height. They claimed that when the energy E of the particle is slightly less than the peak height Ec there is a hyperbolic suspension of a topological Markov chain from which chaotic scattering occurs, whereas for E > Ec there are no bounded orbits. They called the bifurcation at E = Ec an abrupt bifurcation to chaotic scattering.
The aim of this paper is to establish a rigorous mathematical explanation for how chaotic orbits occur via the bifurcation, from the viewpoint of the anti-integrable limit, and to do so for a general range of chaotic scattering problems
Permutations preserving divisibility
We give a proof of a theorem on the common divisibility of polynomials and permuted polynomials (over GF(2)) by a polynomial g(x)
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