4,357 research outputs found

    Change That Abides: A Retrospective Look at Five Community and Family Stengthening Projects and Their Enduring Results

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    Examines the interactions among funders, grantees, and community groups, and outlines the results of three different types of foundation grants for projects in Savannah, Little Rock, Dayton, Alameda County, and Boston. Includes recommendations

    Engaging a New Generation of Philanthropists: Findings from the Pay IT Forward Student Philanthropy Initiative

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    This report focuses on an emerging trend in higher education called student philanthropy, an experiential learning approach where students study social issues in the community and make decisions about distributing funds to nonprofit organizations. Previous research in the field of student philanthropy has revealed promising results: those enrolled in student philanthropy courses have shown a greater awareness of social problems and nonprofits, a heightened sense of responsibility to help others in need, and a greater likelihood to give their time and money in the future to support their community. However, little is known about the ways previous philanthropy experiences of students and components of student philanthropy courses may explain these outcomes.This report examines students enrolled in student philanthropy courses through Pay it Forward, an initiative of the Kentucky, Michigan, and Ohio Campus Compacts that seeks to develop a new generation of philanthropists through infusing the practice of philanthropy as a core component of college coursework. This report asks three key questions about the Pay it Forward course:What are the prior philanthropic experiences of Pay it Forward participants?What features of a Pay it Forward course predict student confidence in their philanthropic skills, abilities, and knowledge?What aspects of a Pay it Forward course predict changes in students' plans to donate money to, volunteer in, and otherwise support their communities

    Star Formation Quenching Timescale of Central Galaxies in a Hierarchical Universe

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    Central galaxies make up the majority of the galaxy population, including the majority of the quiescent population at M>1010M\mathcal{M}_* > 10^{10}\mathrm{M}_\odot. Thus, the mechanism(s) responsible for quenching central galaxies plays a crucial role in galaxy evolution as whole. We combine a high resolution cosmological NN-body simulation with observed evolutionary trends of the "star formation main sequence," quiescent fraction, and stellar mass function at z<1z < 1 to construct a model that statistically tracks the star formation histories and quenching of central galaxies. Comparing this model to the distribution of central galaxy star formation rates in a group catalog of the SDSS Data Release 7, we constrain the timescales over which physical processes cease star formation in central galaxies. Over the stellar mass range 109.510^{9.5} to 1011M10^{11} \mathrm{M}_\odot we infer quenching e-folding times that span 1.51.5 to 0.5  Gyr0.5\; \mathrm{Gyr} with more massive central galaxies quenching faster. For M=1010.5M\mathcal{M}_* = 10^{10.5}\mathrm{M}_\odot, this implies a total migration time of 4 Gyrs\sim 4~\mathrm{Gyrs} from the star formation main sequence to quiescence. Compared to satellites, central galaxies take 2 Gyrs\sim 2~\mathrm{Gyrs} longer to quench their star formation, suggesting that different mechanisms are responsible for quenching centrals versus satellites. Finally, the central galaxy quenching timescale we infer provides key constraints for proposed star formation quenching mechanisms. Our timescale is generally consistent with gas depletion timescales predicted by quenching through strangulation. However, the exact physical mechanism(s) responsible for this still remain unclear.Comment: 16 pages, 11 figure

    A Conceptual Design of a Short Takeoff and Landing Regional Jet Airliner

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    Most jet airliner conceptual designs adhere to conventional takeoff and landing performance. Given this predominance, takeoff and landing performance has not been critical, since it has not been an active constraint in the design. Given that the demand for air travel is projected to increase dramatically, there is interest in operational concepts, such as Metroplex operations that seek to unload the major hub airports by using underutilized surrounding regional airports, as well as using underutilized runways at the major hub airports. Both of these operations require shorter takeoff and landing performance than is currently available for airliners of approximately 100-passenger capacity. This study examines the issues of modeling performance in this now critical flight regime as well as the impact of progressively reducing takeoff and landing field length requirements on the aircraft s characteristics

    Application of CART3D to Complex Propulsion-Airframe Integration with Vehicle Sketch Pad

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    Vehicle Sketch Pad (VSP) is an easy-to-use modeler used to generate aircraft geometries for use in conceptual design and analysis. It has been used in the past to generate metageometries for aerodynamic analyses ranging from handbook methods to Navier-Stokes computational fluid dynamics (CFD). As desirable as it is to bring high order analyses, such as CFD, into the conceptual design process, this has been difficult and time consuming in practice due to the manual nature of both surface and volume grid generation. Over the last couple of years, VSP has had a major upgrade of its surface triangulation and export capability. This has enhanced its ability to work with Cart3D, an inviscid, three dimensional fluid flow toolset. The combination of VSP and Cart3D allows performing inviscid CFD on complex geometries with relatively high productivity. This paper will illustrate the use of VSP with Cart3D through an example case of a complex propulsion-airframe integration (PAI) of an over-wing nacelle (OWN) airliner configuration

    Open Vehicle Sketch Pad Aircraft Modeling Strategies

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    Geometric modeling of aircraft during the Conceptual design phase is very different from that needed for the Preliminary or Detailed design phases. The Conceptual design phase is characterized by the rapid, multi-disciplinary analysis of many design variables by a small engineering team. The designer must walk a line between fidelity and productivity, picking tools and methods with the appropriate balance of characteristics to achieve the goals of the study, while staying within the available resources. Identifying geometric details that are important, and those that are not, is critical to making modeling and methodology choices. This is true for both the low-order analysis methods traditionally used in Conceptual design as well as the highest-order analyses available. This paper will highlight some of Conceptual design's characteristics that drive the designer s choices as well as modeling examples for several aircraft configurations using the open source version of the Vehicle Sketch Pad (Open VSP) aircraft Conceptual design geometry modeler

    The Impact of Domestic and Import Prices on U.S. Lamb Imports: A Production System Approach

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    As U.S. lamb imports increased relative to domestic production, and the relative share of chilled to frozen lamb imports increased, importers of chilled lamb have become less responsive to domestic and import prices, while the direct opposite is the case for frozen lamb imports. From 1990 to 2003, chilled lamb imports from Australia and New Zealand became less and less responsive to U.S. prices, and frozen imports became more responsive. Unconditional own-price elasticities also show that, over time, imports of chilled lamb became less responsive to import prices while frozen imports became more responsive to import prices.lamb, demand, imports, trade, import demand, production, International Relations/Trade,

    The effect of interval intensity on time to exhaustion during high intensity interval training (HIIT) running in recreational male runners

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    High Intensity Interval Training (HIIT) has become extremely popular in recent years, however, current HIIT prescriptions lack guidelines regarding interval intensities and associated margins. The purpose of this study is to investigate Run Time to Exhaustion (Te) and provide insight regarding HIIT intensities for future aerobic exercise programming. Ten healthy adult male recreational runners (Age=22.9 ± 2.5 yr., Ht=1.72 ± 0.1m, BM=74.1 ± 7.4 kg) measured maximal oxygen consumption (VO2max) (52.4 ± 6.1ml/kg/min) with a graded exercise test (GXT). Running speed was determined using ACSM running equation for exercise metabolism. Protocols 1-3 were HIIT running sessions, and Protocol 4 was a continuous running trial, all of the same average intensity (80% VO2max). All HIIT trials implemented aerobic style bout durations of 2 minutes each, with a 1:1 work to active rest/recovery ratio. A repeated measures ANOVA determined that mean Te differed statistically between the 4 protocols. Protocol 1 elicited a significant reduction in mean Te when compared to all other conditions. Based on the findings of this study, recreational runners can monitor variables and/or prescribe intensities to maximize economy and efficacy of aerobic HIIT program implementation
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