374 research outputs found

    Lynx X-Ray Observatory: An Overview

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    Lynx, one of the four strategic mission concepts under study for the 2020 Astrophysics Decadal Survey, provides leaps in capability over previous and planned x-ray missions and provides synergistic observations in the 2030s to a multitude of space- and ground-based observatories across all wavelengths. Lynx provides orders of magnitude improvement in sensitivity, on-axis subarcsecond imaging with arcsecond angular resolution over a large field of view, and high-resolution spectroscopy for point-like and extended sources in the 0.2- to 10-keV range. The Lynx architecture enables a broad range of unique and compelling science to be carried out mainly through a General Observer Program. This program is envisioned to include detecting the very first seed black holes, revealing the high-energy drivers of galaxy formation and evolution, and characterizing the mechanisms that govern stellar evolution and stellar ecosystems. The Lynx optics and science instruments are carefully designed to optimize the science capability and, when combined, form an exciting architecture that utilizes relatively mature technologies for a cost that is compatible with the projected NASA Astrophysics budget

    A Long-Term Vision for Space-Based Interferometry

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    The processes leading to the formation of planets; the extreme physics occurring near the event horizon of black holes; detailed studies of exoplanets through spectral-spatial mapping: new and unique insights into the physical processes involved across nearly the whole gamut of astrophysics await discovery at small angular scales. The fine spatial resolution needed to explore these processes, however, lies beyond the capabilities of current astronomical facilities and nearly all proposed future facilities. Interferometers can crack this angular resolution problem, and space-based interferometry missions promise to explore entirely new regions of scientific phase space, providing unique new insights into the physical processes lurking at small angular scales

    Visual memory predicts Alzheimer’s disease more than a decade before diagnosis

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    BackgroundRecent studies have suggested that AD may reflect a chronic process that begins many years before the clinical expression of dementia. The current study examines premorbid Benton Visual Retention Test (BVRT) and Wechsler Adult Intelligence Scale-vocabulary (WAIS-voc) test scores in order to determine whether long-term deficits in these tests can predict the development of AD decades later in the Baltimore Longitudinal Study of Aging (BLSA).MethodParticipants are volunteers from the BLSA, a multidisciplinary study of normal aging conducted by the National Institute on Aging. A total of 1,425 BLSA participants who were older than 60 years were included in the analyses. Cox proportional hazards models were used to estimate the relative risk of developing AD associated with BVRT and WAIS-voc scores at different time periods up to 20 years before the diagnosis of AD.ResultsThe relative risks for 6 or more BVRT errors vs less than 6 errors at 1 to 3, 3 to 5, 5 to 10, and 10 to 15 years before the diagnosis of AD were 5.69, 2.11, 1.76, and 1.83 (p < 0.05). The relative risk for 15 or more years before diagnosis was not significant (p > 0.10). WAIS-voc scores were not significantly associated with the risk of AD in any time period.ConclusionsA greater number of errors on the BVRT is associated with an increased risk of AD up to 15 years later. Poor visual memory performance may represent an early expression of AD years before diagnosis. This result suggests the need to continue to revise views on the natural history of AD and the possibility of an increased window of opportunity for preventive treatment before definitive diagnosis

    A Thousand Earths: A Very Large Aperture, Ultralight Space Telescope Array for Atmospheric Biosignature Surveys

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    An outstanding, multidisciplinary goal of modern science is the study of the diversity of potentially Earth-like planets and the search for life in them. This goal requires a bold new generation of space telescopes, but even the most ambitious designs yet hope to characterize several dozen potentially habitable planets. Such a sample may be too small to truly understand the complexity of exo-earths. We describe here a notional concept for a novel space observatory designed to characterize 1000 transiting exo-earth candidates. The Nautilus concept is based on an array of inflatable spacecraft carrying very large diameter (8.5 m), very low weight, multiorder diffractive optical elements (MODE lenses) as light-collecting elements. The mirrors typical to current space telescopes are replaced by MODE lenses with a 10 times lighter areal density that are 100 times less sensitive to misalignments, enabling lightweight structure. MODE lenses can be cost-effectively replicated through molding. The Nautilus mission concept has a potential to greatly reduce fabrication and launch costs and mission risks compared to the current space telescope paradigm through replicated components and identical, lightweight unit telescopes. Nautilus is designed to survey transiting exo-earths for biosignatures up to a distance of 300 pc, enabling a rigorous statistical exploration of the frequency and properties of life-bearing planets and the diversity of exo-earths.Gordon and Betty Moore Foundation; NASA's Science Mission DirectorateThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

    Breaking the Cost Curve: Applying Lessons Learned from the James Webb Space Telescope Development

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    This paper looks at the key programmatic and technical drivers of the James Webb Space Telescope and assesses ways to building more cost-effective telescopes in the future. The paper evaluates the top level programmatics for JWST along with the key technical drivers from design through integration and testing. Actual data and metrics from JWST are studied to identify what ultimately drove cost on JWST. Finally, the paper assesses areas where applying lessons learned can reduce costs on future observatories and will provide better insights into critical areas to optimize for cost

    JWST Lessons Learned

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    While there is a lot of focus on how a few key parameters like aperture size and pixel count drive costs of large space telescopes, the JWST experience suggests that a lot more insight is needed to understand and control costs

    CXC chemokines in angiogenesis

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141036/1/jlb0001.pd

    Chemokine receptor expression in tumour islets and stroma in non-small cell lung cancer

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    <p>Abstract</p> <p>Background</p> <p>We have previously demonstrated that tumour islet infiltration by macrophages is associated with extended survival (ES) in NSCLC. We therefore hypothesised that patients with improved survival would have high tumour islet expression of chemokine receptors known to be associated with favourable prognosis in cancer. This study investigated chemokine receptor expression in the tumour islets and stroma in NSCLC.</p> <p>Methods</p> <p>We used immunohistochemistry to identify cells expressing CXCR1, CXCR2, CXCR3, CXCR4, CXCR5 and CCR1 in the tumour islets and stroma in 20 patients with surgically resected NSCLC. Correlations were made with macrophage and mast cell expression.</p> <p>Results</p> <p>There was increased expression of CXCR2, CXCR3, and CCR1 in the tumour islets of ES compared with poor survival (PS) patients (p = 0.007, 0.01, and 0.002, respectively). There was an association between 5 year survival and tumour islet CXCR2, CXCR3 and CCR1 density (p = 0.02, 0.003 and <0.001, respectively) as well as stromal CXCR3 density (p = 0.003). There was a positive correlation between macrophage density and CXCR3 expression (r<sub>s </sub>= 0.520, p = 0.02) and between mast cell density and CXCR3 expression (r<sub>s </sub>= 0.499, p = 0.03) in the tumour islets.</p> <p>Conclusion</p> <p>Above median expression of CXCR2, CXCR3 and CCR1 in the tumour islets is associated with increased survival in NSCLC, and expression of CXCR3 correlates with increased macrophage and mast cell infiltration in the tumour islets.</p

    Assessing Cognitive Abilities in High-Performing Cochlear Implant Users

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    Despite being considered one of the most successful neural prostheses, cochlear implants (CIs) provide recipients with a wide range of speech perception performance. While some CI users can understand speech in the absence of visual cues, other recipients exhibit more limited speech perception. Cognitive skills have been documented as a contributor to complex auditory processing, such as language understanding; however, there are no normative data for existing standardized clinical tests assessing cognitive abilities in CI users. Here, we assess the impact of modality of presentation (i.e., auditory-visual versus visual) for the administration of working memory tests in high-performing CI users in addition to measuring processing speed, cognitive efficiency and intelligence quotient (IQ). Second, we relate performance on these cognitive measures to clinical CI speech perception outcomes.Methods: Twenty one post-lingually deafened, high-performing, adult CI users [age range: 52–88 years; 3 unilateral CI, 13 bimodal (i.e., CI with contralateral hearing aid), 5 bilateral CI] with clinical speech perception scores (i.e., AzBio sentences in quiet for the first-ear CI) of ≥60% were recruited. A cognitive test battery assessing auditory-visual working memory (AVWM), visual working memory (VWM), processing speed, cognitive efficiency and IQ was administered, in addition to clinical measures of speech perception in quiet (i.e., AzBio sentences in quiet). AzBio sentences were assessed in two conditions: first-ear CI only, and best-aided everyday wearing condition. Subjects also provided self-reported measures of performance and benefit from their CI using standardized materials, including the Glasgow Benefit Inventory (GBI) and the Nijmegen Cochlear Implant questionnaire (NCIQ).Results: High-performing CI users demonstrated greater VWM than AVWM recall. VWM was positively related to AzBio scores when measured in the first-ear CI only. AVWM, processing speed, cognitive efficiency, and IQ did not relate to either measure of speech perception (i.e., first-ear CI or best-aided conditions). Subjects’ self-reported benefit as measured by the GBI predicted best-aided CI speech perception performance.Conclusion: In high-performing CI recipients, visual presentation of working memory tests may improve our assessment of cognitive function
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