Central stability for the homology of congruence subgroups and the second homology of Torelli groups

We prove a representation stability result for the second homology groups of Torelli subgroups of mapping class groups and automorphism groups of free groups. This strengthens the results of Boldsen-Hauge Dollerup and Day-Putman. We also prove a new representation stability result for the homology of certain congruence subgroups, partially improving upon the work of Putman-Sam. These results follow from a general theorem on syzygies of certain modules with finite polynomial degree.Comment: Corrections and substantial revisions. 36 pages, 1 figure. To appear in Advances in Mathematic

Structure of the Canola and Biodiesel Industries

The biodiesel industry in the United States has grown significantly in recent years. Production increased from 25 million gallons in 2004 to an estimated 250 million gallons in 2006, and many new plants are being built. Most biodiesel in the United States is produced from soybean oil, but canola offers characteristics which make it a favorable feedstock for biodiesel production. Characteristics of canola oil also make it an increasingly popular choice for human consumption. This study examines the structure of the biodiesel and canola industries. Specifically, the study describes changes in the biodiesel industry, trends in canola production in the United States and Canada, profitability and production risk for canola, the characteristics of canola oil for both human consumption and biodiesel production, the profitability of biodiesel production, and the potential to meet the demand for biodiesel production in the United States.Canola, Biodiesel, Vegetable oil, Resource /Energy Economics and Policy,

Pseudodeterminants and perfect square spanning tree counts

The pseudodeterminant $\textrm{pdet}(M)$ of a square matrix is the last nonzero coefficient in its characteristic polynomial; for a nonsingular matrix, this is just the determinant. If $\partial$ is a symmetric or skew-symmetric matrix then $\textrm{pdet}(\partial\partial^t)=\textrm{pdet}(\partial)^2$. Whenever $\partial$ is the $k^{th}$ boundary map of a self-dual CW-complex $X$, this linear-algebraic identity implies that the torsion-weighted generating function for cellular $k$-trees in $X$ is a perfect square. In the case that $X$ is an \emph{antipodally} self-dual CW-sphere of odd dimension, the pseudodeterminant of its $k$th cellular boundary map can be interpreted directly as a torsion-weighted generating function both for $k$-trees and for $(k-1)$-trees, complementing the analogous result for even-dimensional spheres given by the second author. The argument relies on the topological fact that any self-dual even-dimensional CW-ball can be oriented so that its middle boundary map is skew-symmetric.Comment: Final version; minor revisions. To appear in Journal of Combinatoric

Non-integrality of some Steinberg modules

We prove that the Steinberg module of the special linear group of a quadratic imaginary number ring which is not Euclidean is not generated by integral apartments. Assuming the generalized Riemann hypothesis, this shows that the Steinberg module of a number ring is generated by integral apartments if and only if the ring is Euclidean. We also construct new cohomology classes in the top dimensional cohomology group of the special linear group of some quadratic imaginary number rings.Comment: 17 pages. To appear in Journal of Topolog

Conservation Pricing Of Household Water Use In Public Water Systems In Georgia's Coastal Communities: A Preliminary Exploration

The purpose of this study is to explore the effect of price on residential water use in public water supply systems in Georgia's Coastal region. Particular attention is focused on measures for the elasticity of demand for residential water use inasmuch as a showing of price inelasticity may make the wider adoption of conservation pricing more palatable to small communities with concerns that raising water prices will reduce much-needed revenues.To clarify the nature and importance of the elasticity measure, consider the following simplified example. A community sells 100 units of water for $1.00 per unit. Its' total revenues are$100. Suppose price is increased by 20% to $1.20, and that the units purchased falls by 30$84.00. In this case, we say that demand is "elastic;" the quantity of water used by folks "stretches" relative to the change in price. With elastic demand, rising prices mean lower total revenues. Suppose, however, that with the 20% price increase, demand fell to only 90 units -- a 10% decrease. Total revenues are now $108. In this case we say demand is inelastic -- quantity doesn't really "stretch" much when prices rise. If demand is inelastic, rising prices means higher revenues.From our limited, phase one efforts in these regards, we use aggregate water pricing data from 50 public water supply systems in 28 coastal counties that participated in a survey conducted during late the period 2003-2005. We find strong evidence that, at the margin, residential water use is indeed affected by prices charged for water in this region. We also find what we regard to be reasonably compelling evidence suggesting that residential water demand is inelastic over the range of marginal prices observed in our sample. This latter finding suggests that the use of conservation pricing as a tool for water conservation may not have an adverse effect on community revenues. Indeed, it may well be the case that increasing water prices will increase, not decrease, the community's revenues from the sale of water.In moving to phase two of this work, a great more will be accomplished in terms of refinements in the nature and quality of data used; greater efforts will be placed on attempts to identify functional forms that will yield best estimates for residential water demand in the state. Our ultimate goal is to be capable of responding to the needs of Georgia communities in the coastal region for information related to how one might improve the design of a community's water rate structure, and to conservation pricing policies that will best serve their interests and the interests of the state. Working Paper Number 2005-00

On the Cusp: A Study of Macro- & Microwear in Middle Woodland & Mississippian Skeletal Samples from the Lower Midwest

poster abstractStudies of dental macro- and microwear are emerging as complimentary lines of evidence to archaeological research, enabling scholars to track changes in the mode of subsistence over long and short periods. These tooth wear studies simultaneously allow for analyses within and between age and sex cohorts, providing surrogate measures of a population’s dietary diversity. The current study examines dental wear for two Pre-Columbian samples from the Midcontinental United States. The first (n = 10) is from the Middle Woodland period Mann (12Po2) site, which is located on the Ohio River in southwestern Indiana. Recent radiocarbon dating conducted as part of the current research indicates the site was utilized between AD 127 and 259. Paleoethnobotanical research demonstrates that Middle Woodland people engaged in hunting and gathering, as well as a form of low-level food production that relied on indigenous starchy and oily seeds. The second sample (n = 20) is from the Mississippian period Orendorf (11F107) site in the Central Illinois River Valley. Previous radiometric assays indicate that the site was occupied between AD 1175 and 1250 with the site’s inhabitants taking part in a broad-scale subsistence change to maize agriculture. While research is ongoing and data will be forthcoming for the Mann site, measures of microwear complexity (1.49 asfc) and anisotropy (0.0032 epLsar1.8) from Orendorf reveal a diet that was rough with a low level of orientation between features on the occlusal surfaces of molars. Contrary to previous studies, individuals from Orendorf are atypical among late prehistoric, Midcontinental agriculturalists with a rougher diet more characteristic of preceding foragers or horticulturalists. In a comparison to a worldwide database, dietary roughness for Orendorf is comparable to Early Bronze Age farmers from England; however, the anisotropy value for Orendorf clusters with the Mebrak buckwheat farmers of Nepal and Neolithic samples from Israel

Buy low, sell high, get in now: Low-stakes/low-investment information literacy initiatives pay off big

Become familiar with the concept of low stakes/low investment information literacy initiatives in order to communicate their potential value to faculty members, other librarians, and administrators. Recognize how collaboration between your library and other entities on campus can reinforce information literacy initiatives in order to draw upon the strengths and shared values of existing programs. Learn about successful initiatives in order to generate ideas that would be useful for your institution