2,134 research outputs found

    Effects of Tillage and Grass Filter Strips on Surface Runoff of Water, Nitrate, Sediment, and Atrazine

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    The contamination of streams and other natural bodies of water through agricultural runoff has become a very important environmental issue. Surface water runoff can contain heavy loads of sediment and/or agricultural chemicals, such as nitrogen and atrazine. Conservation tillage methods with vegetative filter strips downslope from cropped fields help· to combat this problem. Conservation tillage has proven effective in decreasing erosion by decreasing exposure of the soil surface to rainfall. Vegetative filter strips provide an area where sediment and agricultural chemicals from cropland can be deposited before the runoff reaches a body of water

    TOBIAS CENTER FOR LEADERSHIP EXCELLENCE

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    poster abstractThe Randall L. Tobias Center for Leadership Excellence was established in 2004. The vision is for it to become one of the top 3 or 4 internationally recognized Centers on Leadership Excellence. The Tobias Center is explicitly cross-disciplinary in its study of leadership and was created as a collaboration of the Kelley School of Business, the School of Public and Environmental Affairs (SPEA) and the School of Education and the Center on Philanthropy. The Tobias Center is an Indiana University center and is housed in the Kelley School in Indianapolis. The programs of the Center fall into three major areas: research, community outreach and education, and teaching. The poster will highlight each of the Center’s programs in each of the three areas. For Research, it will describe the Center’s Faculty Fellows, Doctoral Fellows and Leadership Laboratories. The Center’s community outreach and education programs include the Hoosier Fellows Program, the three lecture programs, and its annual conference. Teaching initiatives of the Tobias Center include the Urban Leadership Education Institute, the Undergraduate Leadership Academy and School of Medicine Leadership course

    Manifestation of superfluidity in an evolving Bose-condensed gas

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    We study the generation of excitations due to an ''impurity''(static perturbation) placed into an oscillating Bose-condensed gas in the time-dependent trapping field. It is shown that there are two regions for the position of the local perturbation. In the first region the condensate flows around the ''impurity'' without generation of excitations demonstrating superfluid properties. In the second region the creation of excitations occurs, at least within a limited time interval, revealing destruction of superfluidity. The phenomenon can be studied by measuring the damping of condensate oscillations at different positions of the ''impurity''

    Dynamical instability of a condensate induced by a rotating thermal gas

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    We study surface modes of the condensate in the presence of a rotating thermal cloud in an axisymmetric trap. By considering collisions that transfer atoms between the condensate and noncondensate, we find that modes which rotate in the same sense as the thermal cloud damp less strongly than counter-rotating modes. We show that above a critical angular rotation frequency, equivalent to the Landau stability criterion, the co-rotating mode becomes dynamically unstable, leading to the possibility of vortex nucleation. This kind of mechanism is proposed as a natural explanation for the formation of vortices observed recently in the experiment of Haljan \emph{et al} {[}P. C. Haljan \emph{et al.}, cond-mat/0106362{]}. We also generalize our stability analysis to treat the case where the stationary state of the condensate already possesses a single vortex.Comment: 4 pages, no figure

    Katanin catalyzes microtubule depolymerization independently of tubulin C-terminal tails

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    Microtubule network remodeling is an essential process for cell development, maintenance, cell division, and motility. Microtubule‐severing enzymes are key players in the remodeling of the microtubule network; however, there are still open questions about their fundamental biochemical and biophysical mechanisms. Here, we explored the ability of the microtubule‐severing enzyme katanin to depolymerize stabilized microtubules. Interestingly, we found that the tubulin C‐terminal tail (CTT), which is required for severing, is not required for katanin‐catalyzed depolymerization. We also found that the depolymerization of microtubules lacking the CTT does not require ATP or katanin\u27s ATPase activity, although the ATP turnover enhanced depolymerization. We also observed that the depolymerization rate depended on the katanin concentration and was best described by a hyperbolic function. Finally, we demonstrate that katanin can bind to filaments that lack the CTT, contrary to previous reports. The results of our work indicate that microtubule depolymerization likely involves a mechanism in which binding, but not enzymatic activity, is required for tubulin dimer removal from the filament ends

    Building Bridges with Boats: Preserving Community History through Intra- and Inter-Institutional Collaboration

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    This chapter discusses Launching through the Surf: The Dory Fleet of Pacific City, a project which documents the historical and contemporary role of dory fishers in the life of the coastal village of Pacific City, Oregon, U.S. Linfield College’s Department of Theatre and Communication Arts, its Jereld R. Nicholson Library, the Pacific City Arts Association, the Pacific City Dorymen\u27s Association, and the Linfield Center for the Northwest joined forces to engage in a collaborative college and community venture to preserve this important facet of Oregon’s history. Using ethnography as a theoretical grounding and oral history as a method, the project utilized artifacts from the dory fleet to augment interview data, and faculty/student teams created a searchable digital archive available via open access. The chapter draws on the authors’ experiences to identify a philosophy of strategic collaboration. Topics include project development and management, assessment, and the role of serendipity. In an era of value-added services where libraries need to continue to prove their worth, partnering with internal and external entities to create content is one way for academic libraries to remain relevant to agencies that do not have direct connections to higher education. This project not only developed a positive “town and gown” relationship with a regional community, it also benefited partner organizations as they sought to fulfill their missions. The project also serves as a potential model for intra- and inter-agency collaboration for all types of libraries

    Vortex stabilization in a small rotating asymmetric Bose-Einstein condensate

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    We use a variational method to investigate the ground-state phase diagram of a small, asymmetric Bose-Einstein condensate with respect to the dimensionless interparticle interaction strength γ\gamma and the applied external rotation speed Ω\Omega. For a given γ\gamma, the transition lines between no-vortex and vortex states are shifted toward higher Ω\Omega relative to those for the symmetric case. We also find a re-entrant behavior, where the number of vortex cores can decrease for large Ω\Omega. In addition, stabilizing a vortex in a rotating asymmetric trap requires a minimum interaction strength. For a given asymmetry, the evolution of the variational parameters with increasing Ω\Omega shows two different types of transitions (sharp or continuous), depending on the strength of the interaction. We also investigate transitions to states with higher vorticity; the corresponding angular momentum increases continuously as a function of Ω\Omega
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