1,798 research outputs found
Spatial correlation as leading indicator of catastrophic shifts
Generic early-warning signals such as increased autocorrelation and variance have been demonstrated in time-series of systems with alternative stable states approaching a critical transition. However, lag times for the detection of such leading indicators are typically long. Here, we show that increased spatial correlation may serve as a more powerful early-warning signal in systems consisting of many coupled units. We first show why from the universal phenomenon of critical slowing down, spatial correlation should be expected to increase in the vicinity of bifurcations. Subsequently, we explore the applicability of this idea in spatially explicit ecosystem models that can have alternative attractors. The analysis reveals that as a control parameter slowly pushes the system towards the threshold, spatial correlation between neighboring cells tends to increase well before the transition. We show that such increase in spatial correlation represents a better early-warning signal than indicators derived from time-series provided that there is sufficient spatial heterogeneity and connectivity in the syste
Rotational isomerism about the 17(20)-bond of steroids and euphoids as shown by the crystal structures of euphol and tirucallol.
Barriers and opportunities to oral health in Dutch-Moroccan children in the Netherlands:a narrative report
Making connections: Using skill theory to recognize how students build and rebuild understanding
In this companion to Marc Schwartz and Kurt Fischer's article, Patricia King and JoNes VanHecke describe how student affairs educators can help students become sophisticated thinkers.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50666/1/155_ftp.pd
Barriers and opportunities to oral health in Dutch-Moroccan children in the Netherlands:a narrative report
The Clumping Transition in Niche Competition: a Robust Critical Phenomenon
We show analytically and numerically that the appearance of lumps and gaps in
the distribution of n competing species along a niche axis is a robust
phenomenon whenever the finiteness of the niche space is taken into account. In
this case depending if the niche width of the species is above or
below a threshold , which for large n coincides with 2/n, there are
two different regimes. For the lumpy pattern emerges
directly from the dominant eigenvector of the competition matrix because its
corresponding eigenvalue becomes negative. For the lumpy
pattern disappears. Furthermore, this clumping transition exhibits critical
slowing down as is approached from above. We also find that the number
of lumps of species vs. displays a stair-step structure. The positions
of these steps are distributed according to a power-law. It is thus
straightforward to predict the number of groups that can be packed along a
niche axis and it coincides with field measurements for a wide range of the
model parameters.Comment: 16 pages, 7 figures;
http://iopscience.iop.org/1742-5468/2010/05/P0500
Community Partnership Through Transformative Justice: the Healing Project at the Oregon State Penitentiary
In the Foreword to Gerard Robinson and Elizabeth English Smith’s Education for Liberation volume on educational initiatives in prison, Newt Gingrich and Van Jones note that educational programs “do something powerful: they give hope and dignity to the incarcerated.” The authors wholeheartedly agree and while they recognize the importance of higher education programs that confer degrees and therefore credentials out in the free world, they find that education can be broadly understood in prison in ways that greatly enhance the hope and dignity of the incarcerated. In this chapter, they explore the creation of a Japanese-style healing garden at the Oregon State Penitentiary (OSP), a maximum security, 2,000-person male prison in Salem, Oregon. This prisoner-led initiative was a resounding success, despite all the odds against it, because it was animated by a philosophy of transformative justice that both prison administration and prisoners could believe in, and it embraced the need for meaningful and inclusive community partnerships
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