On April 10 economist John R. Lott, Jr., formerly of the American Enterprise Institute, filed a defamation lawsuit against economist Steven D. Levitt of the University of Chicago and HarperCollins, the publisher of Levitt's 2005 book, Freakonomics. At issue is what Levitt meant when he wrote that scholars could not "replicate" Lott's results, referring to Lott's 1998 book, More Guns, Less Crime...

The role of grass tussocks in supporting soil microbial biomass (SMB) in grazed ecosystems is not fully understood, nor is the spatial distribution of SMB in response to different grass species. We undertook a study in 1997 that examined ®ne-scale distributions of SMB in grazed experimental paddocks located in the eucalypt woodlands of northern Queensland, Australia. Levels of SMB were determin...

Rho GTPases regulate the assembly of cellular actin structures and are activated by GEFs (guanine-nucleotide-exchange factors) and rendered inactive by GAPs (GTPase-activating proteins). Using the Rho GTPases Cdc42, Rac1 and RhoA, and the GTPase-binding portions of the effector proteins p21-activated kinase and Rhophilin1, we have developed split luciferase assays for detecting both GEF and GAP...

Split cuts are among the most important and well-understood cuts for general mixed-integer programs. In this paper we consider some recent generalizations of split cuts and compare their relative strength. More precisely, we compare the elementary closures of split, cross, crooked cross and general multi-branch split cuts as well as cuts obtained from multi-row and basic relaxations. We present...

ells that passively swell and contract with changes in osmolarity are the key to detecting those changes, say Most cells have at least two mechanisms for maintaining homeostasis in response to changes in salt concentrations. Without these mechanisms, osmotic forces take over: more water and thus less salt outside cells leads water to flood into a cell. But this swelling doesn't occur in most ce...