From Anecdote to Evidence: Assessing the Status and Condition of Arts Education at the State Level

Without solid evidence about the status and condition of arts education in the nation's public schools, it is difficult to make a convincing case for the arts. This research and policy brief draws on the experiences of five states -- Illinois, Kentucky, New Jersey, Rhode Island, and Washington -- as the basis for a discussion of various approaches and methodologies for conducting statewide arts education research

Production Ecology and Stand Dynamics of Young Acadian Forest Stands in Response to Silvicultural Intensity and Compositional Objectives

Early successional stands are common across the Acadian forests of eastern Canada and the Northeastern US. However, productivity and dynamics of these stands, as well as the underlying mechanisms influencing these processes, under different management scenarios are poorly understood. To address this need, I used a factorial experiment that controlled silvicultural intensity and species composition to quantify the effects of varying treatments on early stand dynamics, and the physiological and morphological factors influencing tree performance . Specifically, I studied: 1) species differences in aboveground allometrics, 2) light capture, light-use efficiency (LUE; growth/light capture), and foliar carbon isotope composition (δ13C) of white spruce across a range of growing conditions, and 3) stand growth and yield in response to combinations of silvicultural intensity and compositional objectives. In Chapter 1, a new set of aboveground component biomass equations were developed for sapling-sized trees. In addition, I found that the Forest Inventory and Analysis (FIA) sapling biomass equations underestimated biomass between 10% and 36%, which corresponded to the loss of forest biomass in Maine when FIA switched to new equations. In Chapter 2, I found that aboveground productivity of white spruce seedlings was negatively correlated to competition and positively correlated to light capture. LUE was not correlated with inter-tree competition, suggesting the stands had not reached a density-dependent sorting stage, where use-efficiency tends to increase for dominant trees. δ13C was negatively correlated with competition suggesting that assimilation declined as trees became more light-limited. In Chapter 3, I found that a Populus nigra × P. maximowiczii clone outperformed three P. deltoides × P. nigra clones at the rocky, somewhat poorly drained site, while white spruce yield was negatively correlated with hybrid poplar yield in mixed plantations. Compositional objectives strongly influenced the productivity of naturally regenerated stands over a seven-year period after treatment in Chapter 4, indicating that stands can be directed into distinctly different trajectories depending on the silvicultural treatment. The approach used to study forest productivity in this experiment revealed that hierarchical responses (physiological, tree, and stand) to silviculture-induced growing conditions may influence the long-term trajectories of young Acadian forest stands in the region

Prestigious Houses or Provisional Homes? The ghar as a Symbol of Kathmandu Valley Peri-Urbanism

This article considers an alternative formulation of urban planning generated by three-plus decades of economic and governmental liberalization

Dynamical Arrest in Attractive Colloids: The Effect of Long-Range Repulsion

We study gelation in suspensions of model colloidal particles with short-ranged attractive and long-ranged repulsive interactions by means of three-dimensional fluorescence confocal microscopy. At low packing fractions, particles form stable equilibrium clusters. Upon increasing the packing fraction the clusters grow in size and become increasingly anisotropic until finally associating into a fully connected network at gelation. We find a surprising order in the gel structure. Analysis of spatial and orientational correlations reveals that the gel is composed of dense chains of particles constructed from face-sharing tetrahedral clusters. Our findings imply that dynamical arrest occurs via cluster growth and association.Comment: Final version: Phys. Rev. Lett. 94, 208301 (2005

An HST/WFPC2 Snapshot Survey of 2MASS-Selected Red QSOs

Using simple infrared color selection, 2MASS has found a large number of red, previously unidentified, radio-quiet QSOs. Although missed by UV/optical surveys, the 2MASS QSOs have K-band luminosities that are comparable to "classical" QSOs. This suggests the possible discovery of a previously predicted large population of dust-obscured radio-quiet QSOs. We present the results of an imaging survey of 29 2MASS QSOs observed with WFPC2 onboard the Hubble Space Telescope. I-band images, which benefit from the relative faintness of the nuclei at optical wavelengths, are used to characterize the host galaxies, measure the nuclear contribution to the total observed I-band emission, and to survey the surrounding environments. The 2MASS QSOs are found to lie in galaxies with a variety of morphologies, luminosities, and dynamical states, not unlike those hosting radio-quiet PG QSOs. Our analysis suggests that the extraordinary red colors of the 2MASS QSOs are caused by extinction of an otherwise typical QSO spectrum due to dust near the nucleus.Comment: 23 pages including 9 figures and 7 tables, accepted for publication in ApJ, higher resolution HST images at: http://shapley.as.arizona.edu/~amarble/papers/twomq

Vortex lattice stability and phase coherence in three-dimensional rapidly rotating Bose condensates

We establish the general equations of motion for the modes of a vortex lattice in a rapidly rotating Bose-Einstein condensate in three dimensions, taking into account the elastic energy of the lattice and the vortex line bending energy. As in two dimensions, the vortex lattice supports Tkachenko and gapped sound modes. In contrast, in three dimensions the Tkachenko mode frequency at long wavelengths becomes linear in the wavevector for any propagation direction out of the transverse plane. We compute the correlation functions of the vortex displacements and the superfluid order parameter for a homogeneous Bose gas of bounded extent in the axial direction. At zero temperature the vortex displacement correlations are convergent at large separation, but at finite temperatures, they grow with separation. The growth of the vortex displacements should lead to observable melting of vortex lattices at higher temperatures and somewhat lower particle number and faster rotation than in current experiments. At zero temperature a system of large extent in the axial direction maintains long range order-parameter correlations for large separation, but at finite temperatures the correlations decay with separation.Comment: 10 pages, 2 figures, Changes include the addition of the particle density - vortex density coupling and the correct value of the shear modulu

Selective Sweeps in Growing Microbial Colonies

Evolutionary experiments with microbes are a powerful tool to study mutations and natural selection. These experiments, however, are often limited to the well-mixed environments of a test tube or a chemostat. Since spatial organization can significantly affect evolutionary dynamics, the need is growing for evolutionary experiments in spatially structured environments. The surface of a Petri dish provides such an environment, but a more detailed understanding of microbial growth on Petri dishes is necessary to interpret such experiments. We formulate a simple deterministic reaction-diffusion model, which successfully predicts the spatial patterns created by two competing species during colony expansion. We also derive the shape of these patterns analytically without relying on microscopic details of the model. In particular, we find that the relative fitness of two microbial strains can be estimated from the logarithmic spirals created by selective sweeps. The theory is tested with strains of the budding yeast Saccharomyces cerevisiae, for spatial competitions with different initial conditions and for a range of relative fitnesses. The reaction-diffusion model also connects the microscopic parameters like growth rates and diffusion constants with macroscopic spatial patterns and predicts the relationship between fitness in liquid cultures and on Petri dishes, which we confirmed experimentally. Spatial sector patterns therefore provide an alternative fitness assay to the commonly used liquid culture fitness assays.Molecular and Cellular Biolog