Entanglement Entropy in Jammed CFTs

We construct solutions to the Einstein equations for asymptotically locally Anti-de Sitter spacetimes with four, five, and six dimensional Reissner-Nordstr\"om boundary metrics. These spacetimes are gravitational duals to "jammed" CFTs on those backgrounds at infinite N and strong coupling. For these spacetimes, we calculate the boundary stress tensor as well as compute entanglement entropies for ball shaped regions as functions of the boundary black hole temperature $T_{BH}$. From this, we see how the CFT prevents heat flow from the black hole to the vacuum at spatial infinity. We also compute entanglement entropies for a three dimensional boundary black hole using the AdS C-metric. We compare our results to previous work done in similar spacetimes.Comment: 42 pages, 11 figures, version to appear in JHE

Enumerating the gene sets in breast cancer, a "direct" alternative to hierarchical clustering

<p>Abstract</p> <p>Background</p> <p>Two-way hierarchical clustering, with results visualized as heatmaps, has served as the method of choice for exploring structure in large matrices of expression data since the advent of microarrays. While it has delivered important insights, including a typology of breast cancer subtypes, it suffers from instability in the face of gene or sample selection, and an inability to detect small sets that may be dominated by larger sets such as the estrogen-related genes in breast cancer. The rank-based partitioning algorithm introduced in this paper addresses several of these limitations. It delivers results comparable to two-way hierarchical clustering, and much more. Applied systematically across a range of parameter settings, it enumerates all the partition-inducing gene sets in a matrix of expression values.</p> <p>Results</p> <p>Applied to four large breast cancer datasets, this alternative exploratory method detects more than thirty sets of co-regulated genes, many of which are conserved across experiments and across platforms. Many of these sets are readily identified in biological terms, e.g., "estrogen", "erbb2", and 8p11-12, and several are clinically significant as prognostic of either increased survival ("adipose", "stromal"...) or diminished survival ("proliferation", "immune/interferon", "histone",...). Of special interest are the sets that effectively factor "immune response" and "stromal signalling".</p> <p>Conclusion</p> <p>The gene sets induced by the enumeration include many of the sets reported in the literature. In this regard these inventories confirm and consolidate findings from microarray-based work on breast cancer over the last decade. But, the enumerations also identify gene sets that have not been studied as of yet, some of which are prognostic of survival. The sets induced are robust, biologically meaningful, and serve to reveal a finer structure in existing breast cancer microarrays.</p

Lean Production and the Internet

In this paper the implications for lean production systems of the Internet are explored. Does the World Wide Web facilitate the implementation of Just-in-Time production systems, or alternatively, can it serve as a substitute for JIT? The possible effects on supply chains, production scheduling, inventory control, procurement, quality improvement, and the workforce are some of the issues addressed. Some case examples of use of the Internet for these purposes are presented. Constraints on the use of the Web to foster leanness are discussed and recommendations for integrating the Internet into production systems offered

The Financial Crisis and Global Supply Chains

The financial crisis which erupted in 2007 has already had profound effects on the global supply chains of multinational firms and will likely permanently alter some fundamental supply relationships. This essay explores what some of the consequences have been to date and speculates about future effects. Of course, the length, scope, and severity of the financial and economic crisis will determine how significant and permanent these impacts are, and it is impossible at this point in time to forecast this accurately. But in any case there have already been major developments in global supply chains that are likely to persist after the crisis ends