1,259 research outputs found

    Automated Annotation in the GEBCO Digital Atlas

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    The GEBCO series of bathymetric charts of the world's oceans has developed over a long time, with many changes in format, content and detail. A digital version, the GEBCO Digital Atlas, is currently under preparation using the present (fifth) edition as a starting point. One of the methods for distribution will be the CD-ROM optical disk. With the potential of this medium for handling considerably more information than can be portrayed on paper and the use of the electronic medium for mapping applications, a number of cartographic issues are raised, one of which is feature annotation. Research into techniques for carrying out this process automatically has focused almost exclusively on land-based applications. The application of these techniques to bathymetric mapping is discussed, with particular attention paid to the problems involved with viewing data at arbitrary scale factors, and a number of possible solutions are presented

    Synthesis and alkyne-coupling chemistry of cyclomanganated 1- and 3-acetylindoles, 3-formylindole and analogues

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    The syntheses are reported of new cyclomanganated indole derivatives (1-acetyl-ÎșO-indolyl-ÎșC2)dicarbonylbis(trimethylphosphite)manganese (2), (1-methyl-3-acetyl-ÎșO-indolyl-ÎșC2)tetracarbonylmanganese (4), (3-formyl-ÎșO-indolyl-ÎșC2)tetracarbonylmanganese (5a) and (1-methyl-3-formyl-ÎșO-indolyl-ÎșC2)tetracarbonylmanganese (5b). The unusually complicated crystal structure of 5b has been determined, the first for a cyclomanganated aryl aldehyde. The preparations of a mitomycin-related pyrrolo-indole and related products by thermally promoted and oxidatively (Me3NO) initiated alkyne-coupling reactions of the previously known complex (1-acetyl-ÎșO-indolyl-ÎșC2)tetracarbonylmanganese (1) are reported for different alkynes and solvents. X-ray crystal structures are reported for the dimethyl acetylenedicarboxylate coupling product of 1 (dimethyl 1-methyl-l-hydroxypyrrolo[1,2a]-indole-2,3-dicarboxylate; 6a), and an unusually-cyclised triple insertion product 8 from the coupling of acetylene with 4, in which a cyclopentadiene moiety is η3-allyl-coordinated to Mn through only one double bond and an exocyclic carbon, but which rearranges on heating to an η5-cyclopentadienyl complex

    Controlling and characterizing microstructure in lithium-ion battery electrodes

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    Lithium-ion battery electrodes consist of a functional composite containing electroactive solid particles where redox reactions occur, conductive additives, a polymeric binder to provide mechanical support, and void regions filled with electrolyte during cell fabrication. While much of the focus in the battery materials field is on the chemistry of the electroactive materials that dictate the fundamental limits on the energy density of the cell, the morphology of the electroactive materials and the microstructure of the electrode also have a significant influence on the resulting electrochemical properties. An example of an electrode microstructure is shown in Figure 1. For certain operating conditions and electrode architectures the transport of ions through the electrode microstructure can limit the performance of the cell, which means that controlling and understanding the microstructure can open up battery designs that improve the performance and energy density at the cell level. This strategy should be broadly applicable to multiple battery materials. In this paper, we will describe progress in our lab in synthesizing battery electroactive particles of controllable morphology and processing these particles into composite electrodes. The size, shape, and polydispersity of the particles results in different packing in the electrode and thus different electrode microstructures, while the active material composition is kept constant. Characterization of these electrodes to elucidate microstructure effects on electrochemical performance will also be described, in particular how different transport limitations become relevant for different electrode geometries. Measurements of the tortuosity of the electrodes will be detailed, and the conditions will be determined where transport is limited either within the electroactive particles or through the electrode microstructure. The electrodes described in this paper are functional composites for energy storage applications which is of relevance to the topical theme of this conference. Please click Additional Files below to see the full abstract

    A County-Based Northern Bobwhite Habitat Prioritization Model for Kentucky

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    Planning the management of northern bobwhite (Colinus virginianus) habitat at a statewide-scale is daunting. Native grassland restoration is difficult to manage in Kentucky because . 99% of the Commonwealth’s original grassland area has been lost to agriculture, succession, and development. We created a county prioritization model designed to target areas of grasslands and landowners likely to participate in conservation programs. Our goal was to identify 10% of the state as high priority for bobwhite habitat restoration. We created an east and west model divided by the Appalachian Mountains. The west model was designed to target production-oriented operators farming marginal lands, whereas the east model targeted reclaimed minelands. We used agricultural, landcover, and staff data to build county prioritization models in 2006 and 2011. The models targeted 16.6% and 17.6% of the state in 2006 and 2011, respectively. However, if areas of large, contiguous blocks of forests were excluded, the area total was much closer to 10%. Fifty percent of the high priority counties changed in the west model, and 33% of the counties in the east model changed over 5 years. Implementing a county prioritization model in conjunction with a finer-scale, biological targeted approach could focus conservation efforts with greater potential for success, but the models should be reconstructed at 5- to 10-year intervals to account for changes in conservation delivery potential. A modification of our technique may serve to validate or as an alternative to improve National Bobwhite Conservation Initiative 2.0

    A Study of Undercooling Behavior Of Immiscible Metal Alloys in the Absence of Crucible-Induced Nucleation

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    The purpose of this study is to investigate the question: Would eliminating the crucible eliminate the wall-induced nucleation of one of the liquid phases in an immiscible alloy and result in undercooling of the liquid into the metastable region thereby producing significant differences in the separation process and the microstructure upon solidification. Another primary objective of this research is to study systems with a metastable miscibility gap and to directly determine the metastable liquid miscibility gap by undercooling experiments. Nucleation and growth of droplets in these undercooled metallic liquid-liquid mixtures is also being studied. Results of this investigation indicate that containerless processing of immiscibles may not promote the undercooling of the single-phase liquid into the metastable region. Although no recalescence event was observed for this liquid-liquid transition, undercooling did occur across the miscibility gap for the solidification of the Ti phase that eventually separated

    Results from Kentucky’s 10-year Bobwhite Recovery Plan

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    The northern bobwhite (Colinus virginianus; hereafter, bobwhite) has experienced a precipitous population decline through almost all its historical range over the last 6 decades. We initiated a 10-year restoration plan in Kentucky, USA in 2008 and reported on it through 3 published “Road to Recovery” reports along with 30 peer-reviewed articles and abstracts, 2 technical documents, 7 theses or dissertations, and 11 popular literature pieces. Seven Quail Focus Areas were selected across the state based on site personnel, geographic position (east to west), and land ownership (e.g., private, public, state, federal) for monitoring and habitat management. The focus areas averaged 11,895 acres and area managed for quail on an annual basis ranged from 9% to 42%. Management took the form of herbicide applications, disking, fire, planting, grazing, control of woody vegetation, and mowing. Hierarchical distance sampling models using time-of-removal information to inform detection processes were used to assess bobwhite density on each focus area. Models were based on spring breeding bird point counts in which a suite of grassland songbirds were recorded and fall covey counts in which only bobwhite were recorded. Roadside surveys (direct observation) and hunter harvest information were also used for statewide comparisons of focus areas and statewide trends. Across all years and focus areas a 40% increase in the quail population was observed in 20 years (38%) of the possible 53 years of survey data. Stable to increasing trends were also observed in focal area populations of dickcissel (Spiza americana), eastern meadowlark (Sturnella magna), eastern kingbird (Tyrannus tyrannus), field sparrow (Spizella pusilla), prairie warbler (Setophaga discolor), and Bell’s vireo (Vireo bellii). A focus on habitat management and associated monitoring on relatively small (\u3c20,000 acres) areas was shown to be successful on an individual area, as determined by increases in bird numbers across years and challenges completed in the Quail Plan but did not result in an observed increase in statewide quail indices. Future quail restoration plans in Kentucky should be directed more toward open production land, which is made up of 6 million acres of pastureland, hay land, row crop agriculture, reverting fields, reclaimed mineland, and grasslands. This work will be completed by utilizing working lands, such as field borders in row crop systems and grazing native warm-season grasses in pasture or hay systems, for wildlife activities. Monitoring systems on these production lands will be in the breeding season only and autonomous recording devices will be used in lieu of human observers to cover the greater area of open landscape

    Evidence for deficits in behavioural and physiological responses in aged mice relevant to the psychiatric symptom of apathy

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    Apathy is widely reported in patients with neurological disorders or post viral infection but is also seen in otherwise-healthy aged individuals. This study investigated whether aged male mice express behavioural and physiological changes relevant to an apathy phenotype. Using measures of motivation to work for reward, we found deficits in the progressive ratio task related to rate of responding. In an effort-related decision-making task, aged mice were less willing to exert effort for high value reward. Aged mice exhibited reduced reward sensitivity but also lower measures of anxiety in the novelty supressed feeding test and an attenuated response to restraint stress with lower corticosterone and reduced paraventricular nucleus c-fos activation. This profile of affective changes did not align with those observed in models of depression but suggested emotional blunting. In a test of cognition (novel object recognition), aged mice showed no impairments, but activity was lower in a measure of exploration in a novel environment. Together, these data suggest aged mice show changes across the domains of motivated behaviour, reward sensitivity and emotional reactivity and may be a suitable model for the pre-clinical study of the psychiatric symptom of apathy

    Redox stratification drives enhanced growth in a deposit-feeding invertebrate: Implications for aquaculture bioremediation

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    Effective and affordable treatment of waste solids is a key sustainability challenge for the aquaculture industry. Here, we investigated the potential for a deposit-feeding sea cucumber, Holothuria scabra, to provide a remediation service whilst concurrently yielding a high-value secondary product in a land-based recirculating aquaculture system (RAS). The effect of sediment depth, particle size and redox regime were examined in relation to changes in the behaviour, growth and biochemical composition of juvenile sea cucumbers cultured for 81 d in manipulated sediment systems, describing either fully oxic or stratified (oxic-anoxic) redox regimes. The redox regime was the principal factor affecting growth, biochemical composition and behaviour, while substrate depth and particle size did not significantly affect growth rate or biomass production. Animals cultured under fully oxic conditions exhibited negative growth and had higher lipid and carbohydrate contents, potentially due to compensatory feeding in response to higher micro - phyto benthic production. In contrast, animals in the stratified treatments spent more time feeding, generated faster growth and produced significantly higher biomass yields (626.89 ± 35.44 g m-2 versus 449.22 ± 14.24 g m-2; mean ± SE). Further, unlike in oxic treatments, growth in the stratified treatments did not reach maximum biomass carrying capacity, indicating that stratified sediment is more suitable for culturing sea cucumbers. However, the stratified sediments may exhibit reduced bioremediation ability relative to the oxic sediment, signifying a trade-off between remediation efficiency and exploitable biomass yiel
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