Euler characteristics of moduli spaces of curves

Let Mgn be the moduli space of n-pointed Riemann surfaces of genus g. Denote by Mgn the Deligne-Mumford compactification of Mgn. In the present paper, we calculate the orbifold and the ordinary Euler characteristic of Mgn for any g and n such that n > 2-2g

An Economic Analysis of No-Till Rotations and Effects on Carbon Sequestration and Long Term Sustainability of Agriculture

This study summarizes key economic results from 100 different no-till (NT) crop rotations and a conventional (CT) corn-soybean rotation based on agronomic data from Brookings County, South Dakota for 2001 -2008. A 1200 acre model crop farm was constructed to conduct the farm management budget and simulation analyses. Results indicate: (1) the CT rotation had the highest average net returns, (2) Several four-crop no-till rotations were preferred as producer risk aversion increased, and (3) carbon credit payments would need to be $14 to$36 per acre for the top four NT rotations to be as profitable as the CT rotation.No-till crop systems, Stochastic simulation, Carbon Credit Payments, Farm Management, Production Economics, Q12,

The rational cohomology of the mapping class group vanishes in its virtual cohomological dimension

Let Mod_g be the mapping class group of a genus g >= 2 surface. The group Mod_g has virtual cohomological dimension 4g-5. In this note we use a theorem of Broaddus and the combinatorics of chord diagrams to prove that H^{4g-5}(Mod_g; Q) = 0.Comment: 4 pages. Final version, to appear in IMR

On diffeomorphisms over surfaces trivially embedded in the 4-sphere

A surface in the 4-sphere is trivially embedded, if it bounds a 3-dimensional handle body in the 4-sphere. For a surface trivially embedded in the 4-sphere, a diffeomorphism over this surface is extensible if and only if this preserves the Rokhlin quadratic form of this embedded surface.Comment: Published by Algebraic and Geometric Topology at http://www.maths.warwick.ac.uk/agt/AGTVol2/agt-2-33.abs.htm

Musical Venues in Vienna, Seventeenth Century to the Present

RILM abstract: Consideration of musical venues is often neglected in research on historical performance practice. Many musical works are directly linked to a particular location. The characteristic features (type, size, Acoustics) of the room or building for which the music was written influenced the composer in the creation of his work. A number of venues have had a special place in the musical life of Vienna over the past four centuries. A list of principal Viennese musical buildings (theaters, opera houses, music rooms, concert halls) is included, along with the circumstances surrounding their construction, and the more important musical works--especially premieres--presented in them

The second rational homology group of the moduli space of curves with level structures

Let $\Gamma$ be a finite-index subgroup of the mapping class group of a closed genus $g$ surface that contains the Torelli group. For instance, $\Gamma$ can be the level $L$ subgroup or the spin mapping class group. We show that H_2(\Gamma;\Q) \cong \Q for $g \geq 5$. A corollary of this is that the rational Picard groups of the associated finite covers of the moduli space of curves are equal to \Q. We also prove analogous results for surface with punctures and boundary components.Comment: 27 pages, 4 figures, mild revision. To appear in Adv. Mat