4,641 research outputs found
Extended Peer Communities: Appraising the contributions of tacit knowledges in climate change decision-making
This paper explores the implications of assessing tacit knowledges of climatic change in extended peer communities, as applied in two European research projects on climate action. Post-normal science (PNS) proposes the extension of the peer community to co-produce better quality knowledge for decision-making on issues like climate change, where facts are uncertain, values in dispute, stakes high and decisions urgent. The paper has two aims. The first, more practical, is to explore methods for critically appraising tacit knowledges for climate action, using the example of two ongoing research projects. The second, more conceptual, is to improve practices and discourses surrounding tacit knowledge in current PNS praxis, with close consideration to the implications and challenges involved in including these forms of knowledge in decision making processes. By exploring theoretical perspectives on the topic of tacit knowledge, four challenges facing extended peer communities in engaging with tacit forms of knowledge have been identified: communication, representation, appropriation, and assessment.publishedVersio
Factors and Outcomes Contributing to Pelvic Lymph Node Dissection in Non-Muscle Invasive Bladder Cancer
Bladder cancer represents the 6th most common for men and is classified into muscle-invasive bladder cancer (MIBC) and non-muscle-invasive bladder cancer (NMIBC). NMIBC (T1, Ta, Tis), accounting for approximately 75% of new bladder cancer diagnoses, is limited to the mucosa, submucosa, and lamina propria. Studies have approximated the rate of recurrence in NMIBC between 50 - 70%, which sometimes progresses to muscle invasive disease. Management of NMIBC ranges from surveillance, intravesical chemotherapy to radical cystectomy (RC) and is dependent upon the TNM staging and grading of the tumor. Clinically, staging is determined via imaging, physical exam, and histology on transurethral resection of bladder tumor (TURBT), while pathologic grading is determined via radical cystectomy and pelvic lymph node dissection (PLND).
PLND has been shown to have a therapeutic benefit in localized bladder cancer when done in conjunction with RC, in addition to diagnostic and therapeutic elements. While the relationship between PLND and MIBC has been studied extensively, the role of lymph node (LN) dissection during RC for NMIBC remains unclear, with few studies and conflicting results. Furthermore, although lymph node metastasis has been found to occur in up to 16.2% of NMIBC patients, its reported that nearly half have insufficient PLND during RC and 16.6% have no PLND done at all. The aim of this data analysis is to determine the predictive factors and outcomes for LN positive patients undergoing PLND with RC in NMIBC
Mediastinal Pancreatic Pseudocyst With Hemorrhage and Left Gastric Artery Pseudoaneurysm, Managed With Left Gastric Artery Embolization and Placement of Percutaneous Trans-Hepatic Pseudocyst Drainage
Mediastinal pancreatic pseudocyst (MPP) is a rare, but known, complication of both acute and chronic pancreatitis. Most pseudocysts are associated with alcoholic pancreatitis. Recent advances in endoscopic techniques have shown promising results, with reduced chances of infection and recurrence than with percutaneous drainage, but limited availability restricts widespread use. Left gastric artery pseudoaneurysm with mediastinal pseudocyst has not been described in the literature to date. We report a successful resolution of hemorrhagic MPP with embolization of pseudoaneurysm and percutaneous trans-hepatic pseudocyst drainage
High Thrust-to-Power Annular Engine Technology
Gridded ion engines have the highest efficiency and total impulse of any mature electric propulsion technology, and have been successfully implemented for primary propulsion in both geocentric and heliocentric environments with excellent ground/in-space correlation of performance. However, they have not been optimized to maximize thrust-to-power, an important parameter for Earth orbit transfer applications. This publication discusses technology development work intended to maximize this parameter. These activities include investigating the capabilities of a non-conventional design approach, the annular engine, which has the potential of exceeding the thrust-to-power of other EP technologies. This publication discusses the status of this work, including the fabrication and initial tests of a large-area annular engine. This work is being conducted in collaboration among NASA Glenn Research Center, The Aerospace Corporation, and the University of Michigan
Research collaboration
AbstractThe complexity and cost of cardiovascular medical care dictate research to deliver high quality and cost-conscious cardiovascular care. This goal is aided by modeling medical decision making. To be useful, the modeling must be based on real data so that the results can serve as a guide to actual practice. It is suggested that a registry of randomized clinical trials and larger data bases in cardiovascular disease and health care delivery be established. The registry would be a resource for those desiring to model decision making. The registry would contain key words allowing retrieval by modelers accessing the registry and would contain contact information for consideration of possible collaborative work. The initiation of such a registry should contain plans for its evaluation to determine whether the registry itself is a cost-effective tool to encourage the needed research
Development Status of High-Thrust Density Electrostatic Engines
Ion thruster technology offers the highest performance and efficiency of any mature electric propulsion thruster. It has by far the highest demonstrated total impulse of any technology option, demonstrated at input power levels appropriate for primary propulsion. It has also been successfully implemented for primary propulsion in both geocentric and heliocentric environments, with excellent ground/in-space correlation of both its performance and life. Based on these attributes there is compelling reasoning to continue the development of this technology: it is a leading candidate for high power applications; and it provides risk reduction for as-yet unproven alternatives. As such it is important that the operational limitations of ion thruster technology be critically examined and in particular for its application to primary propulsion its capabilities relative to thrust the density and thrust-to-power ratio be understood. This publication briefly addresses some of the considerations relative to achieving high thrust density and maximizing thrust-to-power ratio with ion thruster technology, and discusses the status of development work in this area being executed under a collaborative effort among NASA Glenn Research Center, the Aerospace Corporation, and the University of Michigan
Syntheses and structure of 8-, 7-, and 6-membered silacycloallenes
Decreasing the ring size of a cyclic allene to rings of fewer than 10 carbons results in deviation of both the normal C=C=C linearity and the orthogonality of the dihedral angle.' To date, the smallest isolable cycloallene is 1-tert-butyl-1,2-cyclooctadiene,2 and the smallest for which structural information is available is the phenylurethane derivative of cyclonona-2,3-dien-1-oJ,l which is bent to 168° and twisted to a dihedral angle of 79.8°. Encouraged by our recent success in the synthesis and structure determination of a tetrasilacyclohexyne,4 we have pursued the syntheses of strained silacycloallenes and report herein the first examples of isolable 6- and ?-membered rings containing 1,2-diene units.Reprinted (adapted) with permission from Journal of the American Chemical Society 115 (1993): 2534, doi:10.1021/ja00059a073. Copyright 1993 American Chemical Society.</p
Exploiting powder X-ray diffraction for direct structure determination in structural biology: the P2X4 receptor trafficking motif YEQGL
We report the crystal structure of the 5-residue peptide acetyl-YEQGL-amide, determined directly from powder X-ray diffraction data recorded on a conventional laboratory X-ray powder diffractometer. The YEQGL motif has a known biological role, as a trafficking motif in the C-terminus of mammalian P2X4 receptors. Comparison of the crystal structure of acetyl-YEQGL-amide determined here and that of a complex formed with the μ2 subunit of the clathrin adaptor protein complex AP2 reported previously, reveals differences in conformational properties, although there are nevertheless similarities concerning aspects of the hydrogen-bonding arrangement and the hydrophobic environment of the leucine sidechain. Our results demonstrate the potential for exploiting modern powder X-ray diffraction methodology to achieve complete structure determination of materials of biological interest that do not crystallize as single crystals of suitable size and quality for single-crystal X-ray diffraction
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