2,587 research outputs found

    Automated, objective texture segmentation of multibeam echosounder data - Seafloor survey and substrate maps from James Island to Ozette Lake, Washington Outer Coast

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    Without knowledge of basic seafloor characteristics, the ability to address any number of critical marine and/or coastal management issues is diminished. For example, management and conservation of essential fish habitat (EFH), a requirement mandated by federally guided fishery management plans (FMPs), requires among other things a description of habitats for federally managed species. Although the list of attributes important to habitat are numerous, the ability to efficiently and effectively describe many, and especially at the scales required, does not exist with the tools currently available. However, several characteristics of seafloor morphology are readily obtainable at multiple scales and can serve as useful descriptors of habitat. Recent advancements in acoustic technology, such as multibeam echosounding (MBES), can provide remote indication of surficial sediment properties such as texture, hardness, or roughness, and further permit highly detailed renderings of seafloor morphology. With acoustic-based surveys providing a relatively efficient method for data acquisition, there exists a need for efficient and reproducible automated segmentation routines to process the data. Using MBES data collected by the Olympic Coast National Marine Sanctuary (OCNMS), and through a contracted seafloor survey, we expanded on the techniques of Cutter et al. (2003) to describe an objective repeatable process that uses parameterized local Fourier histogram (LFH) texture features to automate segmentation of surficial sediments from acoustic imagery using a maximum likelihood decision rule. Sonar signatures and classification performance were evaluated using video imagery obtained from a towed camera sled. Segmented raster images were converted to polygon features and attributed using a hierarchical deep-water marine benthic classification scheme (Greene et al. 1999) for use in a geographical information system (GIS). (PDF contains 41 pages.

    Microwave Characterization of Polymeric Microparticle Morphology

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    Biological cell function and overall health are highly defined by the cell’s morphology. Sorting cells based on their shape is recently a major interest to the biomedical field for the future of medical treatments and health diagnostics. This work presents a new shape-based particle sorting technique using a novel microwave sensing system as a step toward biological cell sorting. The new sensing system consists of a grounded coplanar waveguide (GCPW) transmission line that simultaneously serves as a single-particle microfluidic channel and a microwave sensor, which is paired with a microwave interferometer to boost signal-to-noise ratio (SNR). Polystyrene microspheres, a common organic polymer, are differentiated into different aspect ratios (ARs) using a custom stretching technique to simulate non-spherical biological cells, ideal for isolating volume-effects on the microwave signal due to the low coefficient of variation (CV \u3c 2%) of particle size. Although some microwave measurement data suggests the signal is dependent on microparticle shape, more data points and a machine learning algorithm is needed. The GCPW sensor demonstrates a previously-unattainable level of sensitivity. An early investigation into the effects of orientation of elongated particles on the microwave signal is also explored, as well as the design of an improved GCPW sensor

    Mothers of Soldiers in Wartime: A National News Narrative

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    National news media represent mothers of US combat soldiers in the Iraq War as archetypal good mothers, that is, mothers who continue their maternal work even after their children are deployed. However, not all mothers are depicted as the archetypal patriotic mother, i.e., a good mother who is also stoic and silent about the war and her child\u27s role in it. Mothers of soldiers are portrayed as good mothers who sometimes also voice their attitudes about the war effort. The maternal attitudes ranged from complete support for the war to opposition to the war but support for the soldiers. The findings suggest a picture of wartime motherhood that is more nuanced than the historical image of the patriotic mother suggests

    Trust, morality and altruism in the donation of biological material : the case of Portugal

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    This paper examines a number of social, ethical and cultural issues related to the application of biotechnology. The focus of the paper relies on two different cases of governing biotechnology in Portugal, referring to donation of biological material: the act of donation of eggs and sperm; and volunteers for donation of DNA material for the forensic national DNA database. We analyze the discourses on donation of biological material framing them in rhetorical devices of gift, altruism, informed consent and social responsibility. This comes blended with still unclear and emergent regulation and policies of access, retention, preservation and governing of biological material and of donors’ identification. The risks are mitigated by narratives of science and technology as social progress and providers of public good and health benefits, as well as by underlining the individual responsibility in this domain and by reinforcing the rhetoric of gene quality, based on socio-cultural and bio-genetic criteria

    Signal yields, energy resolution, and recombination fluctuations in liquid xenon

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    This work presents an analysis of monoenergetic electronic recoil peaks in the dark-matter-search and calibration data from the first underground science run of the Large Underground Xenon (LUX) detector. Liquid xenon charge and light yields for electronic recoil energies between 5.2 and 661.7 keV are measured, as well as the energy resolution for the LUX detector at those same energies. Additionally, there is an interpretation of existing measurements and descriptions of electron-ion recombination fluctuations in liquid xenon as limiting cases of a more general liquid xenon re- combination fluctuation model. Measurements of the standard deviation of these fluctuations at monoenergetic electronic recoil peaks exhibit a linear dependence on the number of ions for energy deposits up to 661.7 keV, consistent with previous LUX measurements between 2-16 keV with 3^3H. We highlight similarities in liquid xenon recombination for electronic and nuclear recoils with a comparison of recombination fluctuations measured with low-energy calibration data.Comment: 11 pages, 12 figures, 3 table
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