From prices to incomes: agricultural subsidization without protection?

Drawing on experience with direct income-support programs recently introduced in the European Union, Mexico, and the United States, the authors highlight problems that may arise when a developing economy's agricultural sector moves from price-based subsidies to income support programs. They conclude that income-support programs, despite their theoretical appeal, have many shortcomings and that developing countries may lack the support mechanisms needed to make them effective. The consequences of delinking support from current production decisions, even though fully expected, may be perceived as negative. Producers will undoubtedly face greater variation in prices, and as the ratio of output to input prices will be lower, a negative supply response for the crops affected may in turn reduce demand for agricultural labor. Finally, as with many types of support, the lion's share of support may go not to the target group most in need of support but to large producers. It is important to remember what a direct income-support mechanism does and does not do. Although it increases the income of subsistence landholders, it is not supposed to be a poverty reduction program. Nor is it supposed to be an investment program (as there is no provision for where and how the money will be spent). And because of its association with lower producer prices, it is not expected to induce sectoral growth. Instead, it is a transitional income-redistribution mechanism that could eventually transform agriculture into a fully liberalized sector that helps allocate resources more efficiently. And because it is linked to an asset -land- the lion's share of the payments will inevitably go to large farmers, subject to an upper limit (if such is in place).Economic Theory&Research,Environmental Economics&Policies,Payment Systems&Infrastructure,Agricultural Knowledge&Information Systems,Labor Policies,Economic Theory&Research,Agricultural Knowledge&Information Systems,Agricultural Research,Agribusiness&Markets,Environmental Economics&Policies

Primer for the algebraic geometry of sandpiles

The Abelian Sandpile Model (ASM) is a game played on a graph realizing the dynamics implicit in the discrete Laplacian matrix of the graph. The purpose of this primer is to apply the theory of lattice ideals from algebraic geometry to the Laplacian matrix, drawing out connections with the ASM. An extended summary of the ASM and of the required algebraic geometry is provided. New results include a characterization of graphs whose Laplacian lattice ideals are complete intersection ideals; a new construction of arithmetically Gorenstein ideals; a generalization to directed multigraphs of a duality theorem between elements of the sandpile group of a graph and the graph's superstable configurations (parking functions); and a characterization of the top Betti number of the minimal free resolution of the Laplacian lattice ideal as the number of elements of the sandpile group of least degree. A characterization of all the Betti numbers is conjectured.Comment: 45 pages, 14 figures. v2: corrected typo

The Relative Lie Algebra Cohomology of the Weil Representation of SO(n,1)

In Part 1 of this paper we construct a spectral sequence converging to the relative Lie algebra cohomology associated to the action of any subgroup $G$ of the symplectic group on the polynomial Fock model of the Weil representation, see Section 7. These relative Lie algebra cohomology groups are of interest because they map to the cohomology of suitable arithmetic quotients of the symmetric space $G/K$ of $G$. We apply this spectral sequence to the case $G = \mathrm{SO}_0(n,1)$ in Sections 8, 9, and 10 to compute the relative Lie algebra cohomology groups $H^{\bullet} \big(\mathfrak{so}(n,1), \mathrm{SO}(n); \mathcal{P}(V^k) \big)$. Here $V = \mathbb{R}^{n,1}$ is Minkowski space and $\mathcal{P}(V^k)$ is the subspace of $L^2(V^k)$ consisting of all products of polynomials with the Gaussian. In Part 2 of this paper we compute the cohomology groups $H^{\bullet}\big(\mathfrak{so}(n,1), \mathrm{SO}(n); L^2(V^k) \big)$ using spectral theory and representation theory. In Part 3 of this paper we compute the maps between the polynomial Fock and $L^2$ cohomology groups induced by the inclusions $\mathcal{P}(V^k) \subset L^2(V^k)$.Comment: 64 pages, 5 figure

Causes and Consequences of Collective Turnover: A Meta-Analytic Review

Given growing interest in collective turnover (i.e., employee turnover at unit and organizational levels), the authors propose an organizing framework for its antecedents and consequences and test it using meta-analysis. Based on analysis of 694 effect sizes drawn from 82 studies, results generally support expected relationships across the 6 categories of collective turnover antecedents, with somewhat stronger and more consistent results for 2 categories: human resource management inducements/investments and job embeddedness signals. Turnover was negatively related to numerous performance outcomes, more strongly so for proximal rather than distal outcomes. Several theoretically grounded moderators help to explain average effect-size heterogeneity for both antecedents and consequences of turnover. Relationships generally did not vary according to turnover type (e.g., total or voluntary), although the relative absence of collective-level involuntary turnover studies is noted and remains an important avenue for future research