The approach to criticality in sandpiles

A popular theory of self-organized criticality relates the critical behavior of driven dissipative systems to that of systems with conservation. In particular, this theory predicts that the stationary density of the abelian sandpile model should be equal to the threshold density of the corresponding fixed-energy sandpile. This "density conjecture" has been proved for the underlying graph Z. We show (by simulation or by proof) that the density conjecture is false when the underlying graph is any of Z^2, the complete graph K_n, the Cayley tree, the ladder graph, the bracelet graph, or the flower graph. Driven dissipative sandpiles continue to evolve even after a constant fraction of the sand has been lost at the sink. These results cast doubt on the validity of using fixed-energy sandpiles to explore the critical behavior of the abelian sandpile model at stationarity.Comment: 30 pages, 8 figures, long version of arXiv:0912.320

Courage and Political Resistance

We celebrate courageous acts, but the conventional selection of acts to honor may sanction the slaughter of innocent persons. Most of those who are cited by governments for bravery are military personnel (I shall refer to them, generically, as “soldiers”). We can understand why governments routinely honor soldiers for bravery. Courage is required in warfare. To act as they are told that duty requires, soldiers must overcome reasonable fear of the gruesome dangers that they face. And we can expect governments to claim that their soldiers did not die in vain, but served nobly in a just cause

Ganesh Sitaraman’s Idealized American History

A popular theme among patriots is to celebrate America’s special virtues, which distinguish it radically from European models. Ganesh Sitaraman tells us that political constitutions have generally been designed to prevent socially destabilizing class warfare between the rich, who seek greater domination, and the poor, who would like to redistribute the former’s wealth. America’s Constitution is distinctive because it was consciously designed for a society in which the middle class is large enough to preserve social stability. That is why Sitaraman calls it a “middle-class constitution.

Response

How can one reply to the presentations and discussion of this conference? I think in the same spirit. The paper that took issue most substantially with some writing of mine was Aaron Garrett’s, Courage, Political Resistance, and Self-Deceit. What I have called political resistance has proved difficult for philosophers to theorize about. Aaron helps us to understand it much better. I am truly grateful for that and I am delighted to have provided the occasion for his paper. The same goes for the other contributions to this conference, which address issues more deeply than I have found it possible to do. But that is to be expected; we build on each other’s work. It seems fitting for me to respond in kind. So I will offer some thoughts that are inspired by these discussions. They can be placed under three headings: utility, justice, and law

Violence and Political Incivility

The charge to our panel refers to the deterioration of the political conversation, to deep ... divisions in society, and to recent violence- especially the tragic events in Tuscon. It asks us to identify the virtues required.for our common life as citizens in a democracy and for civil democratic conversation. I shall offer observations and conjectures on each issue, stressing the historical background. Let me suggest, first,. that the nonconstructive and increasingly abusive character of our political discourse may be relatively mild manifestations of an even more troubling malaise of our society- commonplace unlawful violence. I wish to draw your attention to a neglected aspect of that problem. When violence is addressed, we usually focus on practices that are condemned and targeted by public officials and fail to consider the illicit role that officials themselves have often played. A central feature of our civilization since the earliest colonial times has been unlawful violence that is tolerated, encouraged, or engaged in by public officials. Let us go back in time. Land and labor were the two great needs of early English colonists in mainland North America. Land was needed to accommodate increasing numbers of immigrants. Labor was mainly sought by those colonies, such as Virginia, that developed economies, and ultimately social systems, built upon the production and export of cash crops such as tobacco and cotton. The latter also created a demand for agricultural land

The Nature of the Contract Argument

As truth is the first virtue of belief, so justice is of social institutions. That is John Rawls\u27s view, and it seems true, at any rate, of the law. Official acts, laws, and legal arrangements generally are characterized as just or unjust, while other moral categories are much less frequently invoked. Justice seems inseparable from good law. It is therefore striking and important that justice has recently been regarded by prominent legal theorists as rationally disreputable--as, in Kelsen\u27s words, an irrational idea. Many divergent conceptions of social justice have been propounded, and it is held that there is no rational basis for selecting among them. At the extreme, it is said that the principles of justice express basic moral convictions which are merely conventional or subjective, a matter of arbitrary commitment or irrational sentiment

The Importance of Religion for Parents Coping with a Chronically Ill Child

This study examines differences in the stability and consequences of religious coping among parents (N = 102) of chronically ill children. Analyses revealed that changes in religious patterns due to a child\u27s illness were reflected in changes in other, non-religious coping resources. Specifically, parents whose pre-illness religious patterns were satisfactory did not alter their use of other coping resources, whereas parents who reported changes in their religious patterns also made changes in their use of familial financial and social support systems

Heterochromatin-Mediated Gene Silencing Facilitates the Diversification of Olfactory Neurons

An astounding property of the nervous system is its cellular diversity. This diversity, which was initially realized by morphological and electrophysiological differences, is ultimately produced by variations in gene-expression programs. In most cases, these variations are determined by external cues. However, a growing number of neuronal types have been identified in which inductive signals cannot explain the few but decisive transcriptional differences that cause cell diversification. Here, we show that heterochromatic silencing, which we find is governed by histone methyltransferases G9a (KMT1C) and GLP (KMT1D), is essential for stochastic and singular olfactory receptor (OR) expression. Deletion of G9a and GLP dramatically reduces the complexity of the OR transcriptome, resulting in transcriptional domination by a few ORs and loss of singularity in OR expression. Thus, our data suggest that, in addition to its previously known functions, heterochromatin creates an epigenetic platform that affords stochastic, mutually exclusive gene choices and promotes cellular diversity

31064 The Detroit Keloid Scale: A validated tool for rating keloids

Background: No keloid-specific outcome measures exist. Objective: To develop and validate the Detroit Keloid Scale (DKS), a standardized method of keloid assessment to better compare treatments. Methods: Forty-seven physicians were polled to develop the DKS. The scale was validated in 52 patients with keloids against the Vancouver Scar Scale (VSS), Patient and Observer Scar Assessment Scale (POSAS), and Dermatology Life Quality Index (DLQI) by 3 physicians. Results: The interrater reliability was “substantial” for observer component of the DKS and only “moderate” for the VSS and observer POSAS (ICC were 0.80, 0.60, and 0.47, respectively). Pearson’s correlation indicated a “moderate” association between the observer component of DKS with observer component of POSAS (ρ = 0.56, P \u3c.001) and a “substantial” relationship between the observer component of DKS and VSS (ρ = 0.63, P \u3c.001). Pearson’s correlation indicated a “moderate” association between the patient portion of DKS and patient portion of POSAS and the patient portion of the DKS and DLQI (0.61 and 0.60, respectively, P \u3c.05). The DKS total score consistently showed “substantial” relationship with POSAS total score (ρ = 0.65, P \u3c.001). Limitations: Single center study, no intrarater reliability analysis. Conclusions: The substantial interrater reliability of the DKS will allow for improved standardization in future keloid research