When Learning Counts: Rethinking Licenses for School Leaders

Recommends restructuring state licensing systems to focus on the skills and knowledge leaders need to improve learning, and better aligning licenses with the current job demands on principals

The Effect of Treatment of Acidosis on Calcium Balance in Patients with Chronic Azotemic Renal Disease

Small but statistically significant negative calcium balances were found in each of eight studies in seven patients with chronic azotemic renal disease when stable metabolic acidosis was present. Only small quantities of calcium were excreted in the urine, but fecal calcium excretion equaled or exceeded dietary intake. Complete and continuous correction of acidosis by NaHCO3 therapy reduced both urinary and fecal calcium excretion and produced a daily calcium balance indistinguishable from zero. Apparent acid retention was found throughout the studies during acidosis, despite no further reduction of the serum bicarbonate concentration. The negative calcium balances that accompanied acid retention support the suggestion that slow titration of alkaline bone salts provides an additional buffer reservoir in chronic metabolic acidosis. The treatment of metabolic acidosis prevented further calcium losses but did not induce net calcium retention. It is suggested that the normal homeostatic responses of the body to the alterations in ionized calcium and calcium distribution produced by raising the serum bicarbonate might paradoxically retard the repair of skeletal calcium deficits

Performance Pressure and Resource Allocation in Washington

Based on interviews with state, district, and school officials, explores how performance pressures have changed resource allocation decisions. Examines reform goals and how Washington's finance system impedes efforts to link resources to student learning

Density-Dependent Response of an Ultracold Plasma to Few-Cycle Radio-Frequency Pulses

Ultracold neutral plasmas exhibit a density-dependent resonant response to applied radio-frequency (RF) fields in the frequency range of several MHz to hundreds of MHz for achievable densities. We have conducted measurements where short bursts of RF were applied to these plasmas, with pulse durations as short as two cycles. We still observed a density-dependent resonant response to these short pulses. However, the too rapid timescale of the response, the dependence of the response on the sign of the driving field, the response as the number of pulses was increased, and the difference in plasma response to radial and axially applied RF fields are inconsistent with the plasma response being due to local resonant heating of electrons in the plasma. Instead, our results are consistent with rapid energy transfer from collective motion of the entire electron cloud to electrons in high-energy orbits. In addition to providing a potentially more robust way to measure ultracold neutral plasma densities, these measurements demonstrate the importance of collective motion in the energy transport in these systems.Comment: 5 pages, 4 figure

A major advance in powder metallurgy

Ultramet has developed a process which promises to significantly increase the mechanical properties of powder metallurgy (PM) parts. Current PM technology uses mixed powders of various constituents prior to compaction. The homogeneity and flaw distribution in PM parts depends on the uniformity of mixing and the maintenance of uniformity during compaction. Conventional PM fabrication processes typically result in non-uniform distribution of the matrix, flaw generation due to particle-particle contact when one of the constituents is a brittle material, and grain growth caused by high temperature, long duration compaction processes. Additionally, a significant amount of matrix material is usually necessary to fill voids and create 100 percent dense parts. In Ultramet's process, each individual particle is coated with the matrix material, and compaction is performed by solid state processing. In this program, Ultramet coated 12-micron tungsten particles with approximately 5 wt percent nickel/iron. After compaction, flexure strengths were measured 50 percent higher than those achieved in conventional liquid phase sintered parts (10 wt percent Ni/Fe). Further results and other material combinations are discussed

Manifold learning of COPD

Analysis of CT scans for studying Chronic Obstructive Pulmonary Disease (COPD) is generally limited to mean scores of disease extent. However, the evolution of local pulmonary damage may vary between patients with discordant effects on lung physiology. This limits the explanatory power of mean values in clinical studies. We present local disease and deformation distributions to address this limitation. The disease distribution aims to quantify two aspects of parenchymal damage: locally diffuse/dense disease and global homogeneity/heterogeneity. The deformation distribution links parenchymal damage to local volume change. These distributions are exploited to quantify inter-patient differences. We used manifold learning to model variations of these distributions in 743 patients from the COPDGene study. We applied manifold fusion to combine distinct aspects of COPD into a single model. We demonstrated the utility of the distributions by comparing associations between learned embeddings and measures of severity. We also illustrated the potential to identify trajectories of disease progression in a manifold space of COPD