Dual Confinement of Grand Unified Monopoles?

A simple formal computation, and a variation on an old thought experiment, both indicate that QCD with light quarks may confine fundamental color magnetic charges, giving an explicit as well as elegant resolution to the `global color' paradox, strengthening Vachaspati's SU(5) electric-magnetic duality, opening new lines of inquiry for monopoles in cosmology, and suggesting a class of geometrically large QCD excitations -- loops of Z(3) color magnetic flux entwined with light-quark current. The proposal may be directly testable in lattice gauge theory or supersymmetric Yang-Mills theory. Recent results in deeply-inelastic electron scattering, and future experiments both there and in high-energy collisions of nuclei, could give evidence on the existence of Z(3) loops. If confirmed, they would represent a consistent realization of the bold concept underlying the Slansky-Goldman-Shaw `glow' model -- phenomena besides standard meson-baryon physics manifest at long distance scales -- but without that model's isolable fractional electric charges.Comment: 17 pages, standard LaTex, to appear in Physics Reports commemorating Richard Slansk

Sulfur diagenesis in marine sediments

Bacterial sulfate reduction occurs in all marine sediments that contain organic matter. Aqueous sulfide (HS-, H2S), one of the initial products of bacterial sulfide reduction, is extremely reactive with iron bearing minerals: sulfur is fixed into sediments as iron sulfide (first FeS and then Fe2S2). A working definition is given of sulfur diagenesis in marine sediments. Controls and consequences of sulfate reduction rates in marine sediments are examined

Assessing the Determinants and Implications of Teacher Layoffs

Analyzes the factors that predict which teachers are likely to be laid off in Washington state in the current seniority-based system and which would likely be laid off in an effectiveness-based system. Considers implications for student achievement

National Board Certification and Teacher Effectiveness: Evidence from Washington

We study the effectiveness of teachers certified by the National Board for Professional Teaching Standards (NBPTS) in Washington State, which has one of the largest populations of National Board Certified Teachers (NBCTs) in the nation. Based on value-added models in math and reading, we find that NBPTS certified teachers are about 0.01-0.05 student standard deviations more effective than non-NBCTS with similar levels of experience. Certification effects vary by subject, grade level, and certification type, with greater effects for middle school math certificates. We find mixed evidence that teachers who pass the assessment are more effective than those who fail, but that the underlying NBPTS assessment score predicts student achievement. Finally, we use the individual assessment exercise scores to estimate optimal weights for value-added prediction