Finiteness of outer automorphism groups of random right-angled Artin groups

We consider the outer automorphism group Out(A_Gamma) of the right-angled Artin group A_Gamma of a random graph Gamma on n vertices in the Erdos--Renyi model. We show that the functions (log(n)+log(log(n)))/n and 1-(log(n)+log(log(n)))/n bound the range of edge probability functions for which Out(A_Gamma) is finite: if the probability of an edge in Gamma is strictly between these functions as n grows, then asymptotically Out(A_Gamma) is almost surely finite, and if the edge probability is strictly outside of both of these functions, then asymptotically Out(A_Gamma) is almost surely infinite. This sharpens results of Ruth Charney and Michael Farber from their preprint "Random groups arising as graph products", arXiv:1006.3378v1.Comment: 29 pages. Mostly rewritten, results tightened, statements corrected, gaps fille

Rugged pressed disk electrode has low contact potential

Pressed-disk electrode with low contact potential monitors physiological processes. It consists of silver and silver chloride combined with bentonitic clay. The clay affords a surface that permits use over extended periods without contact deterioration

On the second homology group of the Torelli subgroup of Aut(F_n)

Let IA_n be the Torelli subgroup of Aut(F_n). We give an explicit finite set of generators for H_2(IA_n) as a GL_n(Z)-module. Corollaries include a version of surjective representation stability for H_2(IA_n), the vanishing of the GL_n(Z)-coinvariants of H_2(IA_n), and the vanishing of the second rational homology group of the level l congruence subgroup of Aut(F_n). Our generating set is derived from a new group presentation for IA_n which is infinite but which has a simple recursive form.Comment: 39 pages; minor revision; to appear in Geom. Topo

Pressed disc type sensing electrodes with ion- screening means Patent

Characteristics of pressed disc electrode for biological measurement

A Birman exact sequence for the Torelli subgroup of Aut(F_n)

We develop an analogue of the Birman exact sequence for the Torelli subgroup of Aut(F_n). This builds on earlier work of the authors who studied an analogue of the Birman exact sequence for the entire group Aut(F_n). These results play an important role in the authors' recent work on the second homology group of the Torelli group.Comment: 31 pages, minor revision; to appear in Int. J. Algebr. Compu

CHORUSING PATTERNS OF A DIVERSE ANURAN COMMUNITY, WITH AN EMPHASIS ON SOUTHERN CRAWFISH FROGS (LITHOBATES AREOLATUS AREOLATUS)

Wildlife surveys have a critical role in conservation efforts and the collection of life history data. For anuran amphibians these surveys often focus on calling males. In order to further our understanding of anuran ecology, we used automated recording systems to monitor the calling activities of the anuran communities at two beaver-formed lakes and one cattle pond in southeastern Oklahoma. We documented 14 anuran species between 5 February and 28 April 2012. Temperature had a significant effect on the calling patterns of Eastern Narrow-mouthed Toads (Gastrophryne carolinensis), Green Treefrogs (Hyla cinerea), Gray Treefrogs (Hyla versicolor), Southern Crawfish Frogs (Lithobates areolatus areolatus), and Cajun Chorus Frogs (Pseudacris fouquettei). Temperature did not have a significant effect on the calling patterns of Dwarf American Toads (Anaxyrus americanus charlesmithi), American Bullfrogs (Lithobates catesbeianus), or Green Frogs (Lithobates clamitans). There was not a significant relationship between rainfall and calling for L. a. areolatus. The presence of several of these species, including L. a. areolatus and Hurter’s Spadefoots (Scaphiopus hurterii) was unusual because these anurans typically breed in ephemeral, fishless pools, but the beaver lakes are permanent and sustain populations of carnivorous fishes

An experimental investigation of the condensation of silicate grains

Amorphous magnesium silicate smoke particles were condensed from hydrogen and argon atmospheres containing Mg and Si0. A wide range of initial compositions were observed but all particles could be recrystallized into forsterite (Mg2Si04), by heating to 1000 C in vacuum. The amount of smoke formed decreased rapidly with temperatures between 300 and 800 K at reactant partial pressures of about 1 torr