An imPRESsive mimic

Received for publication April 22, 2009; revision received June 18, 2009; and accepted June 19, 2009.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78628/1/j.1537-2995.2009.02362.x.pd

The Statistics of Natural Shapes in Modern Coral Reef Landscapes

Spatial heterogeneity is a fundamental characteristic of modern and ancient depositional settings, and the scaling of many carbonate environments has been shown to follow power function distributions. The difficulty in obtaining information on the horizontal persistence of sedimentary lithotopes at the basin scale has, however, hampered evaluation of this fact over larger geographic areas. In recent years, large‐scale maps of reef facies derived from remotely sensed data have become widely available, allowing for an analysis of reef‐scale map products from 26 sites spread through four reef provinces, covering \u3e7000 km2 of shallow‐water habitat in the U.S. territorial Pacific. For each site, facies maps were decomposed to polygons describing the perimeter of patches of differing sedimentologic/benthic character. A suite of geospatial metrics quantifying unit shape, fractal dimension, and frequency‐area relations was applied to investigate the intra‐ and intersite variability. The spatial architecture of these reef sites displays robust fractal properties over an extended range of scales with remarkable consistency between provinces. These results indicate the possibility of extrapolating information from large to small scales in various depositional environments

A spatial-temporal analysis of section 404 wetland permitting in Texas and Florida: Thirteen years of impact along the coast

Over the past 200 years, an estimated 53% (about 47 million ha) of the original wetlands in the conterminous United States have been lost, mainly as a result of various human activities. Despite the importance of wetlands (particularly along the coast), and a longstanding federal policy framework meant to protect their integrity, the cumulative impact on these natural systems over large areas is poorly understood. We address this lack of research by mapping and conducting descriptive spatial analyses of federal wetland alteration permits (pursuant to section 404 of the Clean Water Act) across 85 watersheds in Florida and coastal Texas from 1991 to 2003. Results show that more than half of the permits issued in both states (60%) fell under the Nationwide permitting category. Permits issued in Texas were typically located outside of urban areas (78%) and outside 100-year floodplains (61%). More than half of permits issued in Florida were within urban areas (57%) and outside of 100-year floodplains (51%). The most affected wetlands types were estuarine in Texas (47%) and palustrine in Florida (55%). We expect that an additional outcome of this work will be an increased awareness of the cumulative depletion of wetlands and loss of ecological services in these urbanized areas, perhaps leading to increased conservation efforts

NEPC Review: Florida Versus Kentucky: School Choice Improves Public School Performance, Too (Bluegrass Institute for Public Policy Solutions, May 2021)

As an increasing number of states adopt or expand choice programs in the form of charter schools, vouchers, tuition tax-credit scholarships, and education savings accounts, questions grow about their efficacy. This review analyzes a recent report from Kentucky&rsquo;s Bluegrass Institute for Public Policy Solutions claiming that NAEP score trends for Florida and Kentucky from the 1990s to 2019 exhibit sufficient evidence that choice programs catalyze significant educational improvement. This review rejects that determination for two reasons. First, the report overlooks the intensity of Florida&rsquo;s focus on preparing students for annual state exams in reading and math since the implementation of its A+ Accountability Plan in 1999, which appears to have had a substantial impact on the state&rsquo;s NAEP scores. Second, in focusing on Florida, the report fails to acknowledge that the majority of the top 10 states with choice programs (as measured by percentage of students enrolled in charter schools) fell short of Kentucky in posting gains on NAEP over this time period. </div

Computation in Classical Mechanics

There is a growing consensus that physics majors need to learn computational skills, but many departments are still devoid of computation in their physics curriculum. Some departments may lack the resources or commitment to create a dedicated course or program in computational physics. One way around this difficulty is to include computation in a standard upper-level physics course. An intermediate classical mechanics course is particularly well suited for including computation. We discuss the ways we have used computation in our classical mechanics courses, focusing on how computational work can improve students' understanding of physics as well as their computational skills. We present examples of computational problems that serve these two purposes. In addition, we provide information about resources for instructors who would like to include computation in their courses.Comment: 6 pages, 3 figures, submitted to American Journal of Physic

Conformational Flexibility in the Enterovirus RNA Replication Platform

A presumed RNA cloverleaf (5′CL), located at the 5′-most end of the noncoding region of the enterovirus genome, is the primary established site for initiation of genomic replication. Stem–loop B (SLB) and stem–loop D (SLD), the two largest stem–loops within the 5′CL, serve as recognition sites for protein interactions that are essential for replication. Here we present the solution structure of rhinovirus serotype 14 5′CL using a combination of nuclear magnetic resonance spectroscopy and small-angle X-ray scattering. In the absence of magnesium, the structure adopts an open, somewhat extended conformation. In the presence of magnesium, the structure compacts, bringing SLB and SLD into close contact, a geometry that creates an extensive accessible major groove surface, and permits interaction between the proteins that target each stem–loop

HTGR Technology Family Assessment for a Range of Fuel Cycle Missions

This report examines how the HTGR technology family can provide options for the once through, modified open cycle (MOC), or full recycle fuel cycle strategies. The HTGR can serve all the fuel cycle missions that an LWR can; both are thermal reactors. Additional analyses are warranted to determine if HTGR “full recycle” service could provide improved consumption of transuranic (TRU) material than LWRs (as expected), to analyze the unique proliferation resistance issues associated with the “pebble bed” approach, and to further test and analyze methods to separate TRISO-coated fuel particles from graphite and/or to separate used HTGR fuel meat from its TRISO coating. The feasibility of these two separation issues is not in doubt, but further R&D could clarify and reduce the cost and enable options not adequately explored at present. The analyses here and the now-demonstrated higher fuel burnup tests (after the illustrative designs studied here) should enable future MOC and full recycle HTGR concepts to more rapidly consume TRU, thereby offering waste management advantages. Interest in “limited separation” or “minimum fuel treatment” separation approaches motivates study of impurity-tolerant fuel fabrication. Several issues are outside the scope of this report, including the following: thorium fuel cycles, gas-cooled fast reactors, the reliability of TRISO-coated particles (billions in a reactor), and how soon any new reactor or fuel type could be licensed and then deployed and therefore impact fuel cycle performance measures

HTGR Technology Family Assessment for a Range of Fuel Cycle Missions

This report examines how the HTGR technology family can provide options for the once through, modified open cycle (MOC), or full recycle fuel cycle strategies. The HTGR can serve all the fuel cycle missions that an LWR can; both are thermal reactors. Additional analyses are warranted to determine if HTGR “full recycle” service could provide improved consumption of transuranic (TRU) material than LWRs (as expected), to analyze the unique proliferation resistance issues associated with the “pebble bed” approach, and to further test and analyze methods to separate TRISO-coated fuel particles from graphite and/or to separate used HTGR fuel meat from its TRISO coating. The feasibility of these two separation issues is not in doubt, but further R&D could clarify and reduce the cost and enable options not adequately explored at present. The analyses here and the now-demonstrated higher fuel burnup tests (after the illustrative designs studied here) should enable future MOC and full recycle HTGR concepts to more rapidly consume TRU, thereby offering waste management advantages. Interest in “limited separation” or “minimum fuel treatment” separation approaches motivates study of impurity-tolerant fuel fabrication. Several issues are outside the scope of this report, including the following: thorium fuel cycles, gas-cooled fast reactors, the reliability of TRISO-coated particles (billions in a reactor), and how soon any new reactor or fuel type could be licensed and then deployed and therefore impact fuel cycle performance measures