OPPORTUNITIES FOR AGRICULTURE TO MITIGATE GREENHOUSE GASES: A GRASS ROOTS APPROACH

Environmental Economics and Policy,

The educational effectiveness of bilingual education

Bilingual education is the use of the native tongue to instruct limited Englishspeaking children. The authors read studies of bilingual education from the earliest period of this literature to the most recent. Of the 300 program evaluations read, only 72 (25%) were methodologically acceptable - that is, they had a treatment and control group and a statistical control for pre-treatment differences where groups were not randomly assigned. Virtually all of the studies in the United States were of elementary or junior high school students and Spanish speakers; The few studies conducted outside the United States were almost all in Canada. The research evidence indicates that, on standardized achievement tests, transitional bilingual education (TBE) is better than regular classroom instruction in only 22% of the methodologically acceptable studies when the outcome is reading, 7% of the studies when the outcome is language, and 9% of the studies when the outcome is math. TBE is never better than structured immersion, a special program for limited English proficient children where the children are in a self-contained classroom composed solely of English learners, but the instruction is in English at a pace they can understand. Thus, the research evidence does not support transitional bilingual education as a superior form of instruction for limited English proficient children

Relics of Supersymmetry in Ordinary 1-flavor QCD: Hairpin Diagrams and Scalar-Pseudoscalar Degeneracy

The large-$N_c$ orientifold planar equivalence between $\mathcal{N}=1$ SUSY Yang-Mills theory and ordinary 1-flavor QCD suggests that low-energy quark-gluon dynamics in QCD should be constrained by the supersymmetry of the parent theory. One SUSY relic expected from orientifold equivalence is the approximate degeneracy of the scalar and pseudoscalar mesons in 1-flavor QCD. Here we study the role of the $q\bar{q}$ annihilation (hairpin) contributions to the meson correlators. These annihilation terms induce mass shifts of opposite sign in the scalar and pseudoscalar channels, making degeneracy plausible. Calculations of valence and hairpin correlators in quenched lattice QCD are consistent with approximate degeneracy, although the errors on the scalar hairpin are large. We also study the role of $q\bar{q}$ annihilation in the 1- and 2-flavor Nambu-Jona Lasinio model, where annihilation terms arise from the chiral field determinant representing the axial U(1) anomaly. Scalar-pseudoscalar degeneracy for the 1-flavor case reduces to a constraint on the relative size of the anomalous and non-anomalous 4-fermion couplings.Comment: 17 pages, 3 figure

Implications of the r-mode instability of rotating relativistic stars

Several recent surprises appear dramatically to have improved the likelihood that the spin of rapidly rotating, newly formed neutron stars (and, possibly, of old stars spun up by accretion) is limited by a nonaxisymmetric instability driven by gravitational waves. Except for the earliest part of the spin-down, the axial l=m=2 mode (an r-mode) dominates the instability, and the emitted waves may be observable by detectors with the sensitivity of LIGO II. A review of these hopeful results is followed by a discussion of constraints on the instability set by dissipative mechanisms, including viscosity, nonlinear saturation, and energy loss to a magnetic field driven by differential rotation.Comment: 20 pages LaTeX2e (stylefile included), 6 eps figures. Review to appear in the proceedings of the 9th Marcel Grossman Meeting, World Scientific, ed. V. Gurzadyan, R. Jantzen, R. Ruffin

Gravitational-wave driven instability of rotating relativistic stars

A brief review of the stability of rotating relativistic stars is followed by a more detailed discussion of recent work on an instability of r-modes, modes of rotating stars that have axial parity in the slow-rotation limit. These modes may dominate the spin-down of neutron stars that are rapidly rotating at birth, and the gravitational waves they emit may be detectable.Comment: 14 pages PTPTeX v.1.0. Contribution to proceedings of the 1999 Yukawa International Semina

A Cost Function Analysis of Crop Insurance Moral Hazard and Agricultural Chemical Use

This paper employs a cost function analysis method to investigate the existence of moral hazard in cotton buy-up insurance. The trans-log cost function estimates of the own-price elasticity of fertilizer, herbicide, and insecticide is -0.222, -0.143, and -0.121, respectively for Mississippi cotton production. Our results found statistically significant relationship between per acre direct cost and cotton buy-up insurance for year 2001 and 2005 in Mississippi. Our results also indicate that moral hazard can either decrease or increase agricultural input usage depending specific production condition in an individual year. But in general the results support effects smaller than anecdotal evidence would suggest.crop insurance, moral hazard, agricultural input use, cost function analysis, cotton, Agribusiness, Agricultural and Food Policy, Demand and Price Analysis, Production Economics, Risk and Uncertainty,

Multivariate Realized Stock Market Volatility

We present a new matrix-logarithm model of the realized covariance matrix of stock returns. The model uses latent factors which are functions of both lagged volatility and returns. The model has several advantages: it is parsimonious; it does not require imposing parameter restrictions; and, it results in a positive-definite covariance matrix. We apply the model to the covariance matrix of size-sorted stock returns and find that two factors are sufficient to capture most of the dynamics. We also introduce a new method to track an index using our model of the realized volatility covariance matrix.Econometric and statistical methods; Financial markets