321 research outputs found

    On Waylen's regular axisymmetric similarity solutions

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    We review the similarity solutions proposed by Waylen for a regular time-dependent axisymmetric vacuum space-time, and show that the key equation introduced to solve the invariant surface conditions is related by a Baecklund transform to a restriction on the similarity variables. We further show that the vacuum space-times produced via this path automatically possess a (possibly homothetic) Killing vector, which may be time-like.Comment: 8 pages, LaTeX2

    Supply-Chain Synchronization: Lessons from Hyundai Motor Company

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    One of the challenges of supply-chain management is developing ways to effectively integrate activities across organizations on the supply chain. Hyundai Motor Company developed mechanisms to coordinate production planning and scheduling activities among supply-chain members. Hyundai Motor\u27s production-and-sales-control (P/SC) department uses regularly scheduled cross-functional meetings and scheduling policies to coordinate supply-chain activities. When implementing this process, the P/SC department overcame structural, environ mental, and behavioral problems. Although Hyundai manage ment concedes that the process is not perfect, communication among supply-chain members has improved, and the P/SC group has successfully promoted mutual understanding and respect among functional areas. The primary benefit, ultimately, is improved customer satisfaction through better integration of functional activities

    bAIoimage analysis: elevating the rate of scientific discovery -- as a community

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    The future of bioimage analysis is increasingly defined by the development and use of tools that rely on deep learning and artificial intelligence (AI). For this trend to continue in a way most useful for stimulating scientific progress, it will require our multidisciplinary community to work together, establish FAIR data sharing and deliver usable, reproducible analytical tools.Comment: 5 pages, 1 figure, opinio

    Age Differences in Behavior and PET Activation Reveal Differences in Interference Resolution in Verbal Working Memory

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    Older adults were tested on a verbal working memory task that used the item-recognition paradigm. On some trials of this task, response-conflict was created by presenting test-items that were familiar but were not members of a current set of items stored in memory. These items required a negative response, but their familiarity biased subjects toward a positive response. Younger subjects show an interference effect on such trials, and this interference is accompanied by activation of a region of left lateral prefrontal cortex. However, there has been no evidence that the activation in this region is causally related to the interference that the subjects exhibit. In the present study, we demonstrate that older adults show more behavioral interference than younger subjects on this task, and they also show no reliable activation at the same lateral prefrontal site. This leads to the conclusion that this prefrontal site is functionally involved in mediating resolution among conflicting responses or among conflicting representations in working memory

    Age Differences in the Frontal Lateralization of Verbal and Spatial Working Memory Revealed by PET

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    Age-related decline in working memory figures prominently in theories of cognitive aging. However, the effects of aging on the neural substrate of working memory are largely unknown. Positron emission tomography (PET) was used to investigate verbal and spatial short-term storage (3 sec) in older and younger adults. Previous investigations with younger subjects performing these same tasks have revealed asymmetries in the lateral organization of verbal and spatial working memory. Using volume of interest (VOI) analyses that specifically compared activation at sites identified with working memory to their homologous twin in the opposite hemisphere, we show pronounced age differences in this organization, particularly in the frontal lobes: In younger adults, activation is predominantly left lateralized for verbal working memory, and right lateralized for spatial working memory, whereas older adults show a global pattern of anterior bilateral activation for both types of memory. Analyses of frontal subregions indicate that several underlying patterns contribute to global bilaterality in older adults: most notably, bilateral activation in areas associated with rehearsal, and paradoxical laterality in dorsolateral prefrontal sites (DLPFC; greater left activation for spatial and greater right activation for verbal). We consider several mechanisms that could account for these age differences including the possibility that bilateral activation reflects recruitment to compensate for neural decline

    Using exomarkers to assess mitochondrial reactive species in vivo

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    Background: The ability to measure the concentrations of small damaging and signalling molecules such as reactive oxygen species (ROS) in vivo is essential to understanding their biological roles. While a range of methods can be applied to in vitro systems, measuring the levels and relative changes in reactive species in vivo is challenging. Scope of review: One approach towards achieving this goal is the use of exomarkers. In this, exogenous probe compounds are administered to the intact organism and are then transformed by the reactive molecules in vivo to produce a diagnostic exomarker. The exomarker and the precursor probe can be analysed ex vivo to infer the identity and amounts of the reactive species present in vivo. This is akin to the measurement of biomarkers produced by the interaction of reactive species with endogenous biomolecules. Major conclusions and general significance: Our laboratories have developed mitochondria-targeted probes that generate exomarkers that can be analysed ex vivo by mass spectrometry to assess levels of reactive species within mitochondria in vivo. We have used one of these compounds, MitoB, to infer the levels of mitochondrial hydrogen peroxide within flies and mice. Here we describe the development of MitoB and expand on this example to discuss how better probes and exomarkers can be developed. This article is part of a Special Issue entitled Current methods to study reactive oxygen species - pros and cons and biophysics of membrane proteins. Guest Editor: Christine Winterbourn. Abbreviations: EPR, electron paramagnetic resonance; GFP, green fluorescent protein; 4-HNE, 4-hydroxynonenal; MitoB, 3-(dihydroxyboronyl)benzyltriphenylphosphonium bromide; MitoP, (3-hydroxybenzyl)triphenylphosphonium bromide; ROS, reactive oxygen species; SOD, superoxide dismutase; TPMP, methyltriphenylphosphonium; TPP, triphenylphosphonium catio

    The Nebraska State Capitol

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    A High Peak of Architectural Progress Some little while ago there appeared on this page a saying to the effect that progress is a blind succession of events fully exposed only through the agency of a capable interpreter. This issue of American Architect is proof of that contention. The Nebraska State Capitol—to which the issue is entirely devoted—is much more than an excellent example of unusual monumental design or even a symbol of democratic government. It marks an important period in the history of building progress. In many ways the architectural genius of Bertram Grosvenor Goodhue dramatized in this design a peak in the history of building accomplishment. As a break from the precedent of tradition the Nebraska State Capitol did much to advance a new and more virile architectural philosophy. From the engineering standpoint the building embodies the cumulative results of American energy, inventive skill and organizing ability; and from all combined points of view it stands as a remarkable interpretation of innumerable events that have shaped the progress of American art. industry and democratic government. For any one of these reasons American Archltect might be proud to publish the Nebraska State Capitol. In combination they make an entire issue necessary to present exclusively a most outstanding example of architectural progress. The Nebraska State Capitol — By Charles Harris Whitaker Highlights of The Capitol\u27s History — By John Edwards A Record of Successful Experiments — By Harry F. Cunningham, A.I.A Symbolism and Inscriptions — By Hartley B. Alexander, Hon. A.I.A. Color in the N ehraska StateCapitol Not in the Specifications — By Oscar H. Murray, A.I.A. An Outline of Mechanical Service Equipment — Meyer, Strong & Jones, Engineers The Story of the Capitol\u27s Construction — By Emile H. Praeger Bertram Grosvenor Goodhue • Exterior Views and Details of North Facade • Exterior Views and Details of South Facade • Plans, Elevations and Details • The Foyer • The Rotunda • The Senate Chamber • The House Chamber • Supreme Court Rooms • Memorial Hall • Governor\u27s Reception Room • Senate Lounge Cover Design by Ernest Born Acknowledgements • As It Looks to the Editors • Trends and Topics of the Times • The Readers Have a Word to Say • New Materials • Book
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