216 research outputs found

    Whitepaper on design and collaborative practices

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    Coming to a large state university, many students have not yet mastered how to effectively learn and study. Creating a freshman learning strategy website would be a step in the right direction to guide and inform students on topics such as time management, writing tips, and study strategies

    Fibrous dysplasia in a Monkey

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    Fibrous dysplasia is a syndrome characterized by dysplastic fibro-osseous skeletal changes. The syndrome has been described in the literature under a number of different terms including osteodystrophia fibrosa, polyostotic osteitis fibrosa, regional fibrocystic disease, osteitis fibrosa cystica, and fibrous dysplasia. The disease has been reported in dogs, horses, swine, monkeys and man

    Langmuir Turbulence under Hurricane Gustav (2008)

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    Extreme winds and complex wave fields drive upper-ocean turbulence in tropical cyclone conditions. Motivated by Lagrangian float observations of bulk vertical velocity variance (VVV) under Hurricane Gustav (2008), upper-ocean turbulence is investigated based on large-eddy simulation (LES) of the wave-averaged Navier–Stokes equations. To realistically capture wind- and wave-driven Langmuir turbulence (LT), the LES model imposes the Stokes drift vector from spectral wave simulations; both the LES and wave model are forced by the NOAA Hurricane Research Division (HRD) surface wind analysis product. Results strongly suggest that without LT effects simulated VVV underestimates the observed VVV. LT increases the VVV, indicating that it plays a significant role in upper-ocean turbulence dynamics. Consistent with observations, the LES predicts a suppression of VVV near the hurricane eye due to wind-wave misalignment. However, this decrease is weaker and of shorter duration than that observed, potentially due to large-scale horizontal advection not present in the LES. Both observations and simulations are consistent with a highly variable upper ocean turbulence field beneath tropical cyclone cores. Bulk VVV, a TKE budget analysis, and anisotropy coefficient (ratio of horizontal to vertical velocity variances) profiles all indicate that LT is suppressed to levels closer to that of shear turbulence (ST) due to misaligned wind and wave fields. VVV approximately scales with the directional surface layer Langmuir number. Such a scaling provides guidance for the development of an upper-ocean boundary layer parameterization that explicitly depends on sea state

    Evidence for a bi-partition of the Younger Dryas Stadial in East Asia associated with inversed climate characteristics compared to Europe

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    The Younger Dryas Stadial (YDS) was an episode of northern hemispheric cooling which occurred within the Last Glacial Interglacial Transition (LGIT). A major driver for the YDS climate was a weakening of the Atlantic Meridional Overturning Circulation (AMOC). It has been inferred that the AMOC began to strengthen mid-YDS, producing a bipartite structure of the YDS in records from continental Europe. These records imply that the polar front and westerlies shifted northward, producing a warmer second phase of the YDS in Europe. Here we present multi-proxy data from the sediments of Lake Suigetsu (Japan), as evidence that a related bi-partition of the YDS also occurred in East Asia. Besides showing for the first time that the bi-partition was not limited to the North Atlantic/European region, the data also imply a climatic dipole between Europe and East Asia since the cold-warm characteristics are reversed at Lake Suigetsu. We suggest that changes in eastward moisture transport from the North Atlantic are the primary mechanism by which the teleconnection can be explained

    Identification of the Changbaishan ‘Millennium’ (B-Tm) eruption deposit in the Lake Suigetsu (SG06) sedimentary archive, Japan: Synchronisation of hemispheric-wide palaeoclimate archives

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    The B-Tm tephra, dispersed during the highly explosive Changbaishan ‘Millennium’ eruption (ca. 940–950 CE) and a key marker layer within the Greenland ice cores, has now been identified in the Lake Suigetsu (SG06) sedimentary sequence, central Japan. The major element geochemistry of the volcanic glasses within this tephra layer are compared to a new glass dataset from the distal type-locality (Tomakomai Port, Hokkaido) and other published ‘Millennium’ eruption/B-Tm deposits, to verify this correlation. The discovery of the B-Tm tephra in the Lake Suigetsu record provides, to date, the most southerly identification of this ash and, crucially, the first direct tie-point between this high-resolution, mid-latitude palaeoclimate archive and the Greenland ice cores. These findings present significant encouragement for on-going research into the tephrostratigraphy of East Asia, focusing on the identification of widely-dispersed tephra layers which can facilitate the synchronisation of disparate palaeoclimate archives and thus enable the assessment of spatio-temporal variations in past climatic change

    Imaging X-Ray Polarimeter Explorer Systems Engineering Approach and Implementation

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    The Imaging X-ray Polarimetry Explorer (IXPE) is a NASA Small Explorer x-ray astrophysics mission being implemented by a geographically dispersed team. Each IXPE partner provides unique capabilities and experience which are utilized to design, build and launch the IXPE observator. A rigorous and iterative systems engineering approach is essential to ensuring the successful realization of reliable and cost effective IXPE mission system. The IXPE collaboration and observatory complexity provide both unique challenges and advantages for project systems engineering. The project uses established and tailored systems engineering (SE) methods and teaming approaches to achieve the IXPE mission goals. The IXPE systems engineering team spans all partner organizations. Currently, the project is in system integration and test working through structural environmental testing–vibration testing is just starting. Systems work is now focused on requirements management and maturity assessments, requirements verification and validation via sell-off packages (SOP) and interface control document (ICD) verification while supporting environmental test planning and execution. IXPE verification, validation and characterization (V&V) starts at the component/unit level and rolls up to appropriate higher levels where V&V compliance is assured by collaborative development by the cross-organizational V&V Team. This paper provides a technical summary of the IXPE concept of operations and mission-system (payload, spacecraft, observatory, ground system, launch vehicle), overviews the IXPE systems engineering approach (communications, project reviews, requirements analysis and management, baseline design and design trade studies, interfaces definition and documentation, resource management), describes the verification, validation and characterization activities (requirements validation, models and simulations validation, systems integration and test (I&T), system validation), discusses risk and opportunities philosophy and implementation, outlines COVID 19 accommodations, itemizes some key challenges and lessons-learned followed by the path to launch and conclusions
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