Mimulus gemmiparus populations: current status and extended search

A research report submitted to: Steve J. Popovich, Botanist, USDA - Forest Service, Arapaho-Roosevelt National Forests.September 30, 2005, revised September 5, 2006.Includes bibliographical references.To more accurately assess the current conservation status of the rare plant Mimulus gemmiparus (Phrymaceae), we visited all previously known sites of occurrence and documented the location, size, and condition of populations, and we searched for additional populations in nearby areas. Our search results indicate that more occurrences of M. gemmiparus are likely. Details regarding the populations and our searches are presented here. Includes a 2006 addendum and update by David A. Steingraeber

Tennessee\u27s National Impact on Teacher Evaluation Law & Policy: An Assessment of Value-Added Model Litigation

Over the last decade or so, federal and state education policymakers embraced the use of value added models (VAMs) to evaluate teachers’ performance and make high-stakes employment decisions (e.g., tenure, merit pay, termination of employment). VAMs are complicated statistical models that attempt to estimate a teacher’s contribution to student test scores, particularly those in mathematics and reading. Educational researchers, as well as many teachers and unions, however, have objected to the use of VAMs noting that these models fail to adequately account for variables outside of teachers’ control that contribute to a student’s education performance. Subsequently, many teachers challenged the use of VAMs through the courts. This article assesses those challenges

Testing the Universality of Entropic Segregation at Polymer Surfaces

This study addresses entropic segregation effects at the surfaces of monodisperse and bidisperse melts. For the monodisperse melts, we focus on the segregation of chain ends to the surface, and for the bidisperse melts, we examine the segregation of short polymers to the surface. Universal shapes have been predicted for their concentration profiles, but the derivations rely on the mean-field approximation, which only treats the excluded-volume interactions in an approximate manner. To test whether or not the predictions hold up when the polymers are rigorously prevented from overlapping, we compare mean-field calculations with Monte Carlo simulations performed on the exact same model. Apart from a significant increase in the statistical segment length, the rigorous enforcement of excluded-volume interactions has a relatively small effect on the mean-field predictions. In particular, the universal profiles predicted by mean-field theory are found to be accurate.NSER

Variability in the freshwater balance of northern Marguerite Bay, Antarctic Peninsula: results from δ18O

We investigate the seasonal variability in freshwater inputs to the Marguerite Bay region (Western Antarctic Peninsula) using a time series of oxygen isotopes in seawater from samples collected in the upper mixed layer of the ocean during 2002 and 2003. We find that meteoric water, mostly in the form of glacial ice melt, is the dominant freshwater source, accounting for up to 5% of the near-surface ocean during the austral summer. Sea ice melt accounts for a much smaller percentage, even during the summer (maximum around 1%). The seasonality in meteoric water input to the ocean (around 2% of the near-surface ocean) is not dissimilar to that of sea ice melt (around 2% in 2002 and 1% in 2003), contradicting the assumption that sea ice processes dominate the seasonal evolution of the physical ocean environment close to the Antarctic continent. Three full-depth profiles of oxygen isotopes collected in successive Decembers (2001, 2002 and 2003) indicate that around 4 m of meteoric water is present in the water column at this time of year, and around 1 m of sea ice formed from this same water column. The predominance of glacial melt is significant, since it is known to be an important factor in the operation of the ecosystem, for example by providing a source of nutrients and modifying the physical environment to control the spatial extent and magnitude of phytoplankton blooms. The Western Antarctic Peninsula is undergoing a very rapid change in climate, with increasing ocean and air temperatures, retreating glaciers and increases in precipitation associated with changes in atmospheric circulation. As climate change continues, we expect meteoric water inputs to the adjacent ocean to rise further. Sea ice in this sector of the Antarctic has shown a climatic decrease, thus we expect a reduction in oceanic sea ice melt fractions if this change continues. Continued monitoring of the oceanic freshwater budget at the western Peninsula is needed to track these changes as they occur, and to better understand their ecological consequences