Siltation Related to Beaver Dam Decomposition in the Little Kankakee River

The Little Kankakee River (LKR) in LaPorte County, Indiana is an uncommon example of a good, cold-water fishery in northwest Indiana. However, the river has variable sedimentation levels; deep silt often covers gravel and sand, smothering invertebrates, a key food source for higher trophic organisms. The LKR contains a naturally-decomposing, abandoned beaver dam. The purpose of this study is to monitor its impact upon upstream and downstream silt levels. This research intends to identify possible sources of variability in silt levels, benefiting restoration teams in determining effects of dam removals. Furthermore, understanding the impact and pattern of silt levels could aid the monitoring of river health. Water depth, silt depth, flow rate, and a description of the river bed are measured and recorded. Flow rate fluctuations will be charted against monthly precipitation, noting changes in flow. It is predicted that the beaver dam causes fluctuating siltation by collecting silt upstream and then releasing variable amounts during dam decomposition. Preliminary results indicate the narrow sections of the river have faster water flow and less silt. The beaver dam impedes flow, widens the river, and reduces velocity, allowing fine sediment to accumulate. It is predicted that if the beaver dam decomposes rapidly, then trapped silt above the dam will percolate rapidly through the system stopping at wide sections of the river. If the beaver dam deteriorates slowly, then silt accumulations may not be measureable and leave silt in the system much longer

Exact results for a tunnel-coupled pair of trapped Bose-Einstein condensates

A model describing coherent quantum tunneling between two trapped Bose-Einstein condensates is shown to admit an exact solution. The spectrum is obtained by the algebraic Bethe ansatz. An asymptotic analysis of the Bethe ansatz equations leads us to explicit expressions for the energies of the ground and first excited states in the limit of {\it weak} tunneling and all energies for {\it strong} tunneling. The results are used to extract the asymptotic limits of the quantum fluctuations of the boson number difference between the two Bose-Einstein condensates and to characterize the degree of coherence in the system.Comment: 5 pages, RevTex, No figure

Exact solution at integrable coupling of a model for the Josephson effect between small metallic grains

A model is introduced for two reduced BCS systems which are coupled through the transfer of Cooper pairs between the systems. The model may thus be used in the analysis of the Josephson effect arising from pair tunneling between two strongly coupled small metallic grains. At a particular coupling strength the model is integrable and explicit results are derived for the energy spectrum, conserved operators, integrals of motion, and wave function scalar products. It is also shown that form factors can be obtained for the calculation of correlation functions. Further, a connection with perturbed conformal field theory is made.Comment: 12 pages, latex, no figure

Local Norms and Gifted and Talented Identification in Arkansas: Can it Help Improve Student Diversity?

In the past decades, the gifted and talented (G/T) community has wrestled with an important question about improving equity: How can we best use research to increase student diversity in G/T education? There are many suggestions for answering this question but using local norms, where students are selected based on comparisons with others from a similar school context using traditional measures, has attracted much attention. In some districts, using local norms and universal screening has greatly improved student diversity, whereas, in other districts, the findings have been unclear. Thus it seems useful to study local contexts. In this study, we leveraged Arkansas’ administrative data to answer a similar question: “Would using district/school assessment norms improve student diversity in G/T identification in Arkansas?” We found no consistent evidence that using district/school norms would improve racial and programmatic diversity (i.e., special education students, English language learners, and students from low-come and minority backgrounds). We still urge school districts, however, to consider employing local norms in identifying G/T students as it would limit human errors in identification and increase the alignment between students’ academic aptitude and G/T services, especially for students of racial and demographic groups that the current system has identified successfully

The Art of Refusal: The Experience of Grant Makers and Grant Seekers

This paper examines communications between grantmakers and grantseeking nonprofits at the point of grant refusal. It provides survey results from both types of organizations, and aims to increase understanding in this area, identify areas of organizational learning, and provide suggestions for future practices

Investigations at the Vollrath Blacksmith Shop (41BX786), San Antonio, Bexar County, Texas

In May 1988, archival research was initiated to evaluate the archaeological potential of New City Block 102, Lots 10 through 15, in downtown San Antonio, Texas, proposed site of the new Bexar County Justice Center parking garage. The research indicated that the southern portion of Lots 10 and 11 would required further investigation at the 1874 site of Vollrath\u27s blacksmith shop. Field excavations were conducted in August 1988. This report discusses the archival research and the results of the field excavations

R₀ Analysis of a Spatiotemporal Model for a Stream Population

Water resources worldwide require management to meet industrial, agricultural, and urban consumption needs. Management actions change the natural flow regime, which impacts the river ecosystem. Water managers are tasked with meeting water needs while mitigating ecosystem impacts. We develop process-oriented advection-diffusion-reaction equations that couple hydraulic flow to population growth, and we analyze them to assess the effect of water flow on population persistence. We present a new mathematical framework, based on the net reproductive rate R0 for advection-diffusion-reaction equations and on related measures. We apply the measures to population persistence in rivers under various flow regimes. This work lays the groundwork for connecting R0 to more complex models of spatially structured and interacting populations, as well as more detailed habitat and hydrological data

Exact solution, scaling behaviour and quantum dynamics of a model of an atom-molecule Bose-Einstein condensate

We study the exact solution for a two-mode model describing coherent coupling between atomic and molecular Bose-Einstein condensates (BEC), in the context of the Bethe ansatz. By combining an asymptotic and numerical analysis, we identify the scaling behaviour of the model and determine the zero temperature expectation value for the coherence and average atomic occupation. The threshold coupling for production of the molecular BEC is identified as the point at which the energy gap is minimum. Our numerical results indicate a parity effect for the energy gap between ground and first excited state depending on whether the total atomic number is odd or even. The numerical calculations for the quantum dynamics reveals a smooth transition from the atomic to the molecular BEC.Comment: 5 pages, 4 figure

Solvable models of Bose-Einstein condensates: a new algebraic Bethe ansatz scheme

A new algebraic Bethe ansatz scheme is proposed to diagonalise classes of integrable models relevant to the description of Bose-Einstein condensates in dilute alkali gases. This is achieved by introducing the notion of Z-graded representations of the Yang-Baxter algebra.Comment: 14 pages, latex, no figure

2017 Scientific Consensus Statement: land use impacts on the Great Barrier Reef water quality and ecosystem condition, Chapter 1: the condition of coastal and marine ecosystems of the Great Barrioer Reef and their responses to water quality and disturbances

The condition of coastal and marine ecosystems on the Great Barrier Reef and their responses to water quality and disturbances. The Great Barrier Reef marine ecosystems and their associated catchments are part of a dynamic, interconnected system. This chapter provides an up-to-date review of the state of knowledge relating to the conditions and trends of key Great Barrier Reef coastal and marine ecosystems, including current knowledge on key drivers of change and activities leading to pressures and impacts on these ecosystems. Drivers include the impacts of land run-off, coastal development activities and other disturbances such as extreme weather events that influence Great Barrier Reef water quality and the health of marine and coastal ecosystems