3,726 research outputs found

    Forecasting and Intercepting the 28 May 2013 Bennington, KS Tornadic Supercell: A Student Perspective

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    This project examines the 28 May 2013 mesoscale case over north-central Kansas and focuses on the step-by-step process from a student perspective. The project describes the tools, models, parameters, and observations used to determine the focus for the day, including a classic loaded-gun sounding measured and observed by the field team. The decisions made by the team on this day placed them in position to observe an EF-3 tornado near Bennington, Kansas. The main goal of the project is to educate students about how to forecast and safely observe severe weather events through a how-to-guide compiled from experiences in the Valparaiso University Meteorology Department program, Severe Convective Storms Field Study. The project will demonstrate how to apply the knowledge from the course to a real-time, in the field, forecast. Although forecasting is not an exact science just yet, the guide will help educate future students and others on how to utilize various tools and techniques in order to accurately forecast for convective weather

    On the Mass Function, Multiplicity, and Origins of Wide-Orbit Giant Planets

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    A major outstanding question regarding the formation of planetary systems is whether wide-orbit giant planets form differently than close-in giant planets. We aim to establish constraints on two key parameters that are relevant for understanding the formation of wide-orbit planets: 1) the relative mass function and 2) the fraction of systems hosting multiple companions. In this study, we focus on systems with directly imaged substellar companions, and the detection limits on lower-mass bodies within these systems. First, we uniformly derive the mass probability distributions of known companions. We then combine the information contained within the detections and detection limits into a survival analysis statistical framework to estimate the underlying mass function of the parent distribution. Finally, we calculate the probability that each system may host multiple substellar companions. We find that 1) the companion mass distribution is rising steeply toward smaller masses, with a functional form of NM1.3±0.3N\propto M^{-1.3\pm0.3}, and consequently, 2) many of these systems likely host additional undetected sub-stellar companions. Combined, these results strongly support the notion that wide-orbit giant planets are formed predominantly via core accretion, similar to the better studied close-in giant planets. Finally, given the steep rise in the relative mass function with decreasing mass, these results suggest that future deep observations should unveil a greater number of directly imaged planets.Comment: 19 pages, 10 figures, accepted to Ap

    Forecasting and Intercepting the 28 May 2013 Bennington, KS Tornadic Supercell: A Student Perspective

    Get PDF
    This project examines the 28 May 2013 mesoscale case over north-central Kansas and focuses on the step-by-step process from a student perspective. The project describes the tools, models, parameters, and observations used to determine the focus for the day, including a classic loaded-gun sounding measured and observed by the field team. The decisions made by the team on this day placed them in position to observe an EF-3 tornado near Bennington, Kansas. The main goal of the project is to educate students about how to forecast and safely observe severe weather events through a how-to-guide compiled from experiences in the Valparaiso University Meteorology Department program, Severe Convective Storms Field Study. The project will demonstrate how to apply the knowledge from the course to a real-time, in the field, forecast. Although forecasting is not an exact science just yet, the guide will help educate future students and others on how to utilize various tools and techniques in order to accurately forecast for convective weather

    Texas Watershed Planning Short Course Final Report

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    Proper training of watershed coordinators and water professionals is needed to ensure that watershed protection efforts are adequately planned, coordinated and implemented. To provide this training, the Texas Watershed Planning Short Course was developed through a coordinated effort led by the Texas Water Resources Institute and funded by the U.S. Environmental Protection Agency through the Texas Commission on Environmental Quality. The Texas Water Resources Institute partnered with the Texas AgriLife Extension Service, Texas AgriLife Research, Texas State Soil and Water Conservation Board, Texas Commission on Environmental Quality, U.S. Environmental Protection Agency, Texas State University-River Systems Institute and the Texas Institute for Applied Environmental Research to develop and conduct this short course. Since 2008, four week-long Watershed Planning Short Courses have been hosted, providing training to over 160 watershed professionals on sustainable proactive approaches to managing water quality throughout the state. The Watershed Planning Short Course provides guidance on stakeholder coordination, education, and outreach; meeting the U.S. Environmental Protection Agency’s nine key elements of a watershed protection plan; data collection and analysis; and the tools available for plan development. Along with the Watershed Planning Short Courses, water professionals were invited to attend Texas Watershed Coordinator Roundtables, held biannually, to (1) provide a forum for establishing and maintaining dialogue between watershed coordinators, (2) facilitate interactive solutions to common watershed issues faced throughout the state, and (3) add to the fundamental knowledge conveyed at the short courses. More than 250 water professionals attended the four Texas Watershed Coordinator Roundtables held in Temple, Georgetown and Dallas. Topics of discussion included sustainable organizational structure for long-term watershed protection plan implementation; the U.S. Environmental Protection Agency’s Region 6 review guide of watershed-based plans; strategies and expectations for demonstrating successful implementation and financing watershed protection plans. Additional workshops also offered to further familiarize watershed coordinators with watershed management tools provided by the U.S. Environmental Protection Agency included Getting In Step Workshops and Key EPA Internet Tools for Watershed Management courses. The Getting In Step Workshop aims to improve the effectiveness of nonpoint source outreach in Texas and the internet tools course familiarizes users with online watershed management tools provided by the U.S. Environmental Protection Agency. More than 90 watershed professionals participated in four Getting In Step Workshops offered in Houston, Austin, Dallas and Georgetown. Nearly 40 watershed professionals participated in the two Key EPA Internet Tools for Watershed Management courses offered in San Marcos and Dallas. Also, the Texas Water Resources Institute coordinated with Wildland Hydrology to provide an Applied Fluvial Geomorphology Short Course with 40 water resource professionals participating to better understand the fundamentals and general principles of river behavior. To assist watershed professionals in searching for funding programs, the Texas Water Resources Institute worked with the Environmental Finance Center at Boise State University to update the Directory of Watershed Resources to include Texas-specific funding programs. The Environmental Finance Center Network is an EPA-sponsored, university-based program providing financial outreach services. The Directory of Watershed Resources is an on-line, searchable database for watershed restoration funding. The database includes information on federal, state, private, and other funding sources and assistance and allows Texas users to query information in a variety of ways including by agency sponsor or keyword, or by a detailed search. In total, the combined courses, workshops and meetings have reached out to more than 350 watershed coordinators and water professionals and will continue to do so by hosting biannual Watershed Coordinator Roundtable meetings and training opportunities

    On the centroid of increasing trees

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    A centroid node in a tree is a node for which the sum of the distances to all other nodes attains its minimum, or equivalently a node with the property that none of its branches contains more than half of the other nodes. We generalise some known results regarding the behaviour of centroid nodes in random recursive trees (due to Moon) to the class of very simple increasing trees, which also includes the families of plane-oriented and dd-ary increasing trees. In particular, we derive limits of distributions and moments for the depth and label of the centroid node nearest to the root, as well as for the size of the subtree rooted at this node

    Effects of drinking-water filtration on Cryptosporidium Seroepidemiology, Scotland

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    Continuous exposure to low levels of Cryptosporidium oocysts is associated with production of protective antibodies. We investigated prevalence of antibodies against the 27-kDa Cryptosporidium oocyst antigen among blood donors in 2 areas of Scotland supplied by drinking water from different sources with different filtration standards: Glasgow (not filtered) and Dundee (filtered). During 2006–2009, seroprevalence and risk factor data were collected; this period includes 2007, when enhanced filtration was introduced to the Glasgow supply. A serologic response to the 27-kDa antigen was found for ≈75% of donors in the 2 cohorts combined. Mixed regression modeling indicated a 32% step-change reduction in seroprevalence of antibodies against Cryptosporidium among persons in the Glasgow area, which was associated with introduction of enhanced filtration treatment. Removal of Cryptosporidium oocysts from water reduces the risk for waterborne exposure, sporadic infections, and outbreaks. Paradoxically, however, oocyst removal might lower immunity and increase the risk for infection from other sources
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