4,597 research outputs found

    Photometric identification of the periods of the first candidate extragalactic magnetic massive stars

    Full text link
    Galactic stars belonging to the Of?p category are all strongly magnetic objects exhibiting rotationally modulated spectral and photometric changes on timescales of weeks to years. Five candidate Of?p stars in the Magellanic Clouds have been discovered, notably in the context of ongoing surveys of their massive star populations. Here we describe an investigation of their photometric behaviour, revealing significant variability in all studied objects on timescales of one week to more than four years, including clearly periodic variations for three of them. Their spectral characteristics along with these photometric changes provide further support for the hypothesis that these are strongly magnetized O stars, analogous to the Of?p stars in the Galaxy.Comment: 9pages, accepted by A&

    Catabolism and Deactivation of the Lipid-Derived Hormone Jasmonoyl-Isoleucine

    Get PDF
    The oxylipin hormone jasmonate controls myriad processes involved in plant growth, development, and immune function. The discovery of jasmonoyl-l-isoleucine (JA-Ile) as the major bioactive form of the hormone highlights the need to understand biochemical and cell biological processes underlying JA-Ile homeostasis. Among the major metabolic control points governing the accumulation of JA-Ile in plant tissues are the availability of jasmonic acid, the immediate precursor of JA-Ile, and oxidative enzymes involved in catabolism and deactivation of the hormone. Recent studies indicate that JA-Ile turnover is mediated by a ω-oxidation pathway involving members of the CYP94 family of cytochromes P450. This discovery opens new opportunities to genetically manipulate JA-Ile levels for enhanced resistance to environmental stress, and further highlights ω-oxidation as a conserved pathway for catabolism of lipid-derived signals in plants and animals. Functional characterization of the full complement of CYP94 P450s promises to reveal new pathways for jasmonate metabolism and provide insight into the evolution of oxylipin signaling in land plants

    Geologic Mapping in the Hesperia Planum Region of Mars

    Get PDF
    Hesperia Planum, characterized by a high concentration of mare-type wrinkle ridges and ridge rings, encompasses > 2 million square km in the southern highlands of Mars. The most common interpretation is that the plains were emplaced as "flood" lavas with total thicknesses of <3 km [4-10]. The wrinkle ridges on its surface make Hesperia Planum the type locale for "Hesperian-aged ridged plains" on Mars, and wrinkle-ridge formation occurred in more than one episode. Hesperia Planum s stratigraphic position and crater-retention age define the base of the Hesperian System. However, preliminary results of geologic mapping reveal that the whole of Hesperia Planum is unlikely to be composed of the same materials, emplaced at the same geologic time. To unravel these complexities, we are generating a 1:1.5M-scale geologic map of Hesperia Planum and its surroundings. To date, we have identified 4 distinct plains units within Hesperia Planum and are attempting to determine the nature and relative ages of these materials

    Comparison of Cultivation Methods Impact on Playability of \u3cem\u3eAgrostis stolonifera\u3c/em\u3e Greens

    Get PDF
    Creeping bentrgrass putting greens require intense management due to stoloniferous growth (thatch accumulation) and excessive wear and traffic by equipment and golfers. Increases in thatch and soil compaction are often managed with cultivation practices, which lead to downtime for golfers. Field research was conducted in Knoxville, TN, and Elizabethtown, KY, to compare new and traditional cultivation methods for their impact on playability on creeping bentgrass putting greens. Treatments included air injection, dry sand injection, solid tine cultivation topdressed with sand, hollow tine cultivation topdressed with sand, and non-treated control. Treatments were arranged in a randomized complete block design replicated three times at two locations. As determined 15 minutes after treatments, air injection resulted in the least reduction of green turfgrass cover, no ball roll reduction from the control, and lower reductions in surface firmness compared to other methods tested. Hollow tine had the greatest reduction in green turfgrass cover, lowest ball roll distance, and greatest reductions in surface firmness. Air injection had a lower impact on surface characteristics than hollow or solid cultivation. Because turf cover, ball roll, and firmness can all affect putting green playability, these findings indicate that air injection cultivation has the smallest impact on golfers immediately after a cultivation event

    Lunar Geologic Mapping: A Preliminary Map of a Portion of the LQ-10 ("Marius") Quadrangle

    Get PDF
    Since the first lunar mapping program ended in the 1970s, new topographical, multispectral, elemental and albedo imaging datasets have become available (e.g., Clementine, Lunar Prospector, Galileo). Lunar science has also advanced within the intervening time period. A new systematic lunar geologic mapping effort endeavors to build on the success of earlier mapping programs by fully integrating the many disparate datasets using GIS software and bringing to bear the most current understanding of lunar geologic history. As part of this program, we report on a 1:2,500,000-scale preliminary map of a subset of Lunar Quadrangle 10 ("LQ-10" or the "Marius Quadrangle," see Figures 1 and 2), and discuss the first-order science results. By generating a geologic map of this region, we can constrain the stratigraphic and geologic relationships between features, revealing information about the Moon s chemical and thermal evolution

    Mapping Hesperia Planum, Mars

    Get PDF
    Hesperia Planum, characterized by a high concentration of mare-type wrinkle ridges and ridge rings [1-4], encompasses > 2 million km2 in the southern highlands of Mars (Fig. 1). The most common interpretation is that the plains were emplaced as flood lavas with total thicknesses of <3 km [4-10]. The wrinkle ridges on its surface make Hesperia Planum the type locale for Hesperian-aged ridged plains on Mars [e.g., 9], and recent investigations reveal that wrinkle-ridge formation occurred in more than one episode [4]. Hesperia Planum s stratigraphic position and crater-retention age [e.g., 9, 11-12] define the base of the Hesperian System. However, preliminary results of geologic mapping reveal that the whole of Hesperia Planum is unlikely to be composed of the same materials, emplaced at the same geologic time. To unravel these complexities, we are generating a 1:1.5M-scale geologic map of Hesperia Planum and its surroundings (Fig. 1). To date, we have identified 4 distinct plains units within Hesperia Planum and are attempting to determine the nature and relative ages of these materials (Fig. 2) [13-15]

    Public Interest Attorney Profiles

    Get PDF

    Reduced regional brain cortical thickness in patients with heart failure.

    Get PDF
    AimsAutonomic, cognitive, and neuropsychologic deficits appear in heart failure (HF) subjects, and these compromised functions depend on cerebral cortex integrity in addition to that of subcortical and brainstem sites. Impaired autoregulation, low cardiac output, sleep-disordered-breathing, hypertension, and diabetic conditions in HF offer considerable potential to affect cortical areas by loss of neurons and glia, which would be expressed as reduced cortical thicknesses. However, except for gross descriptions of cortical volume loss/injury, regional cortical thickness integrity in HF is unknown. Our goal was to assess regional cortical thicknesses across the brain in HF, compared to control subjects.Methods and resultsWe examined localized cortical thicknesses in 35 HF and 61 control subjects with high-resolution T1-weighted images (3.0-Tesla MRI) using FreeSurfer software, and assessed group differences with analysis-of-covariance (covariates; age, gender; p&lt;0.05; FDR). Significantly-reduced cortical thicknesses appeared in HF over controls in multiple areas, including the frontal, parietal, temporal, and occipital lobes, more markedly on the left side, within areas that control autonomic, cognitive, affective, language, and visual functions.ConclusionHeart failure subjects show reduced regional cortical thicknesses in sites that control autonomic, cognitive, affective, language, and visual functions that are deficient in the condition. The findings suggest chronic tissue alterations, with regional changes reflecting loss of neurons and glia, and presumably are related to earlier-described axonal changes. The pathological mechanisms contributing to reduced cortical thicknesses likely include hypoxia/ischemia, accompanying impaired cerebral perfusion from reduced cardiac output and sleep-disordered-breathing and other comorbidities in HF

    Biodigital publics: personal genomes as digital media artifacts

    Get PDF
    The recent proliferation of personal genomics and direct-to-consumer (DTC) genomics has attracted much attention and publicity. Concern around these developments has mainly focused on issues of biomedical regulation and hinged on questions of how people understand genomic information as biomedical and what meaning they make of it. However, this publicity amplifies genome sequences which are also made as internet texts and, as such, they generate new reading publics. The practices around the generation, circulation and reading of genome scans do not just raise questions about biomedical regulation, they also provide the focus for an exploration of how contemporary public participation in genomics works. These issues around the public features of DTC genomic testing can be pursued through a close examination of the modes of one of the best known providers—23andMe. In fact, genome sequences circulate as digital artefacts and, hence, people are addressed by them. They are read as texts, annotated and written about in browsers, blogs and wikis. This activity also yields content for media coverage which addresses an indefinite public in line with Michael Warner’s conceptualisation of publics. Digital genomic texts promise empowerment, personalisation and community, but this promise may obscure the compliance and proscription associated with these forms. The kinds of interaction here can be compared to those analysed by Andrew Barry. Direct-to-consumer genetics companies are part of a network providing an infrastructure for genomic reading publics and this network can be mapped and examined to demonstrate the ways in which this formation both exacerbates inequalities and offers possibilities for participation in biodigital culture
    corecore