1,254 research outputs found

    Fostering Critical Thinking about Climate Change: Applying Community Psychology to an Environmental Education Project with Youth

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    This article argues for the participation of community psychology in issues of global climate change. The knowledge accumulated and experience gained in the discipline of community psychology have great relevance to many topics related to the environment. Practitioners of community psychology could therefore make significant contributions to climate change mitigation. To illustrate this assertion, we describe an education project conducted with youth engaged in a community-based environmental organization. This initiative was motivated by the idea that engaged and critically aware youth often become change agents for social movements. Towards this purpose, rather than using mass marketing strategies to motivate small behavior changes, this project focused intensively on a few youth with the vision that these youth would also influence those around them to rethink their environmental habits. This project was influenced by five community psychology concepts: stakeholder participation, ecological and systems thinking, social justice, praxis, and empirical grounding. In this article we discuss the influence of these concepts on the project’s outcomes, as measured through an evaluative study conducted to assess the impacts of the project on the participating youth in terms of their thinking and action. The contributions of community psychology were found to have greatly impacted the quality of the project and the outcomes experienced by the youth

    Optimum constrained image restoration filters

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    The filter was developed in Hilbert space by minimizing the radius of gyration of the overall or composite system point-spread function subject to constraints on the radius of gyration of the restoration filter point-spread function, the total noise power in the restored image, and the shape of the composite system frequency spectrum. An iterative technique is introduced which alters the shape of the optimum composite system point-spread function, producing a suboptimal restoration filter which suppresses undesirable secondary oscillations. Finally this technique is applied to multispectral scanner data obtained from the Earth Resources Technology Satellite to provide resolution enhancement. An experimental approach to the problems involving estimation of the effective scanner aperture and matching the ERTS data to available restoration functions is presented

    Constrained optimization of image restoration filters

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    A linear shift-invariant preprocessing technique is described which requires no specific knowledge of the image parameters and which is sufficiently general to allow the effective radius of the composite imaging system to be minimized while constraining other system parameters to remain within specified limits

    Conceptual Design of an In-Space Cryogenic Fluid Management Facility

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    The conceptual design of a Spacelab experiment to develop the technology associated with low gravity propellant management is presented. The proposed facility consisting of a supply tank, receiver tank, pressurization system, instrumentation, and supporting hardware, is described. The experimental objectives, the receiver tank to be modeled, and constraints imposed on the design by the space shuttle, Spacelab, and scaling requirements, are described. The conceptual design, including the general configurations, flow schematics, insulation systems, instrumentation requirements, and internal tank configurations for the supply tank and the receiver tank, is described. Thermal, structural, fluid, and safety and reliability aspects of the facility are analyzed. The facility development plan, including schedule and cost estimates for the facility, is presented. A program work breakdown structure and master program schedule for a seven year program are included

    Conceptual design of an in-space cryogenic fluid management facility, executive summary

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    The conceptual design of a Spacelab experiment to develop the technology associated with low gravity propellant management is summarized. The preliminary facility definition, conceptual design and design analysis, and facility development plan, including schedule and cost estimates for the facility, are presented

    Food habits of Steller sea lions (Eumetopias jubatus) off Oregon and northern California, 1986–2007

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    We described the diet of the eastern stock of Steller sea lions (Eumetopias jubatus) from 1416 scat samples collected from five sites in Oregon and northern California from 1986 through 2007. A total of 47 prey types from 30 families were identified. The most common prey was Pacific hake (Merluccius productus), followed by salmonids (Oncorhynchus spp.), skates (Rajidae), Pacific lamprey (Lampetra tridentata), herrings (Clupeidae), rockfish (Sebastes spp.), and northern anchovy (Engraulis mordax). Steller sea lion diet composition varied seasonally, annually, and spatially. Hake and salmonids were the most commonly identified prey in scats collected during the summer (breeding season), whereas hake and skate were most common in the nonbreeding season. Continued research on Steller sea lion diet and foraging behavior in the southern extent of their range is necessary to address issues such as climate change, interaction with competing California sea lions, and predation impacts on valuable or sensitive fish stocks

    WiggleZ Dark Energy Survey: Cosmological neutrino mass constraint from blue high-redshift galaxies

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    The absolute neutrino mass scale is currently unknown, but can be constrained by cosmology. The WiggleZ high redshift, star-forming, and blue galaxy sample offers a complementary data set to previous surveys for performing these measurements, with potentially different systematics from nonlinear structure formation, redshift-space distortions, and galaxy bias. We obtain a limit of ∑m_ν<0.60  eV (95% confidence) for WiggleZ+Wilkinson Microwave Anisotropy Probe. Combining with priors on the Hubble parameter and the baryon acoustic oscillation scale gives ∑m_ν<0.29  eV, which is the strongest neutrino mass constraint derived from spectroscopic galaxy redshift surveys

    PRSA hydrogen tank thermal acoustic oscillation study

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    The power reactant storage assembly (PRSA) hydrogen tank test data were reviewed. Two hundred and nineteen data points illustrating the effect of flow rate, temperature ratio and configuration were identified. The test data were reduced to produce the thermal acoustic oscillation parameters. Frequency and amplitude were determined for model correlation. A comparison of PRSA hydrogen tank test data with the analytical models indicated satisfactory agreement for the supply and poor agreement for the full line

    Sterile neutrinos in the Milky Way: Observational constraints

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    We consider the possibility of constraining decaying dark matter by looking out through the Milky Way halo. Specifically we use Chandra blank sky observations to constrain the parameter space of sterile neutrinos. We find that a broad band in parameter space is still open, leaving the sterile neutrino as an excellent dark matter candidate.Comment: Submitted to ApJL, 4 pages, 4 figure
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