Local Cohomology and non commutative Gorenstein algebras

In this paper we continue the study of non connected graded Gorenstein algebras initiated in a previous paper, the main result is the proof of a version of the Local Cohomology formula

Top and bottom tensor couplings from a color octet scalar

We compute the one-loop contributions from a color octet scalar to the tensor anomalous couplings of top and bottom quarks to gluons, photons and W bosons. We use known constraints on the parameters of the model to compare the predicted size of these couplings with existing phenomenological constraints.Comment: References added, matches accepted version for publicatio

Adopt a hypothetical pup: A count data approach to the valuation of wildlife.

The willingness to pay for a coyote conservation program is estimated using a novel payment-vehicle, based on how many coyotes respondents would be willing to sponsor. This hypothetical scenario mimics an increasingly popular type of actual market. Data from a phone survey conducted in Prince Edward Island are analyzed using count data models that consider different processes explaining zero responses and the level of positive responses. This is particularly important in the case of coyotes, often regarded as a bad. Estimates of willingness to pay per coyote around $18-$20 and annual consumer surplus per respondent of about $35-$42 are obtained.coyotes, wildlife, contingent valuation, count data, zero- inflation

An Estimation of Residential Water Demand Using Co-Integration and Error Correction Techniques

In this paper short- and long-run price elasticities of residential water demand are estimated using co-integration and error-correction methods. Unit root tests reveal that water use series and series of other variables affecting use are non-stationary. However, a long-run co-integrating relationship is found in the water demand model, which makes it possible to obtain a partial correction term and to estimate an error correction model. The empirical application uses monthly time-series observations from Seville (Spain). The price-elasticity of demand is estimated as around -0.1 in the short run and -0.5 in the long run. These results are robust to the use of different specifications.seasonal unit roots; residential water demand; price elasticity; time-series; co-integration; Error Correction Model

A Box-Cox double-hurdle model of wildlife valuation: the citizen’s perspective.

A stated-preference approach is used to elicit the attitudes of the general public towards coyotes conservation. The payment vehicle is presented in a way that explicitly prompts individuals to adopt a citizen perspective, rather than a consumer perspective, when responding to the survey. To deal with the large numbers of zero responses, a Box- Cox Double Hurdle specification is used to model separately individuals’ choices about whether to support conservation or not and their choice about the degree of support. The results show that simpler analyses that do not account explicitly for this two different decisions would lead to misleading conclusions in the study of nuisance wildlife. The study uses a survey conducted in Prince Edward Island (Canada).Coyotes; wildlife valuation, citizen versus consumer preferences; paymentvehicle; Box-Cox, double hurdle time-series, co- integration, Error Correction Model.

Skew group algebras, invariants and Weyl Algebras

The aim of this paper is two fold: First to study finite groups $G$ of automorphisms of the homogenized Weyl algebra $B_{n}$, the skew group algebra $B_{n}\ast G$, the ring of invariants $B_{n}^{G}$, and the relations of these algebras with the Weyl algebra $A_{n}$, with the skew group algebra $A_{n}\ast G$, and with the ring of invariants $A_{n}^{G}$. Of particular interest is the case $n=1$. In the on the other hand, we consider the invariant ring \QTR{sl}{C}[X]^{G} of the polynomial ring $K[X]$ in $n$ generators, where $G$ is a finite subgroup of Gl(n,\QTR{sl}{C}) such that any element in $G$ different from the identity does not have one as an eigenvalue. We study the relations between the category of finitely generated modules over \QTR{sl}{C}[X]^{G} and the corresponding category over the skew group algebra \QTR{sl}{C}% [X]\ast G. We obtain a generalization of known results for $n=2$ and $G$ a finite subgroup of $Sl(2,C)$. In the last part of the paper we extend the results for the polynomial algebra $C[X]$ to the homogenized Weyl algebra $B_{n}$