624 research outputs found

    Primary Intraocular Lymphoma

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    What do we know about knowledge integration : fusing micro- and macro-organizational perspectives

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    Knowledge integration is the raison d’etre for the existence of the firm (Grant, 1996a; Kogut & Zander, 1992) and has been widely studied across many subfields in management and organizational studies. However, few constructs have received as much scholarly attention as knowledge integration while remaining so equivocally defined and measured, leading to a confusing array of conceptualizations, undermining its theoretical, empirical, and practical usefulness. As a theoretical construct, knowledge integration also cuts across the macro- and microlevels, gaining attention from scholars interested in explaining the microfoundations of strategy and capabilities (e.g., Felin & Hesterly, 2007; Lewin, Massini, & Peeters, 2011). However, the interplay among these micro and macro factors is often overlooked, and its implications for theory building are ignored. To address these issues, we examine and integrate micro- and macro-organizational perspectives on knowledge integration. We provide a review of its definitions and offer our definition based on key dimensions identified. We discuss and analyze the micro and macro perspectives, presenting key assertions, propositions, limitations, and conclusions from representative studies. Finally, we integrate the diverse perspectives we discuss, showing how their interplay can enrich future scholarship and our understanding of knowledge integration as a key organizational construct

    Single shot cathode transverse momentum imaging in high brightness photoinjectors

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    In state of the art photoinjector electron sources, thermal emittance from photoemission dominates the final injector emittance. Therefore, low thermal emittance cathode developments and diagnostics are very important. Conventional thermal emittance measurements for the high gradient gun are time-consuming and thus thermal emittance is not measured as frequently as quantum efficiency during the lifetime of photocathodes, although both are important properties for the photoinjector optimizations. In this paper, a single shot measurement of photoemission transverse momentum, i.e., thermal emittance per rms laser spot size, is proposed for photocathode rf guns. By tuning the gun solenoid focusing, the electrons' transverse momenta at the cathode are imaged to a downstream screen, which enables a single shot measurement of both the rms value and the detailed spectra of the photoelectrons' transverse momenta. Both simulations and proof of principle experiments are reported

    Comparison of Oral, Tympanic and Fresh Urine Temperature in Healthy Young Adult Males in Kingdom Suadi Arabia

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    Background: Core body temperature (CBT) is commonly evaluated by measuring oral (OT) and tympanic membrane (TT) temperatures; however, there are considerable debates on which of these methods is the most appropriate.Objective: To evaluate concordance of OT and TT with CBT.Material and Methods: OT, TT and fresh urine temperature (FUT) were measuredsimultaneously in 45 apparently healthy young adult males from Buraydah, Qassim, KSA during July 2015. All readings were obtained between 7:00 and 10:00 pm according to the standard methods. FUT was used as indicator of CBT.Results: OT (36.35Β±0.41Β° C) was significantly higher compared with TT (35.99Β±0.81Β° C, P = 0.013) as well as FUT (35.55Β±0.76Β° C, P < 0.001). TT was significantly higher compared with FUT (P = 0.003). Using one sample t-test, the difference between OT and TT (0.36Β±0.92Β° C, P = 0.011), OT and FUT (0.80Β±0.90Β° C, P < 0.001) and TT and FUT (0.44Β±0.80Β° C, P = 0.001) were significantly above zero. Disconcordance of the OT, TT and FUT measurements are further illustrated by Bland-Altman plots. There were no significant correlations between OT and TT as well as between OT and FUT. However, TT correlated positively with FUT (r = 0.48, P = 0.001).Conclusions: OT and TT are inappropriate measures for CBT. CBT has influence on TT, but not OT.Key words: Core body temperature, oral, tympanic, urine

    Longtime behavior of nonlocal Cahn-Hilliard equations

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    Here we consider the nonlocal Cahn-Hilliard equation with constant mobility in a bounded domain. We prove that the associated dynamical system has an exponential attractor, provided that the potential is regular. In order to do that a crucial step is showing the eventual boundedness of the order parameter uniformly with respect to the initial datum. This is obtained through an Alikakos-Moser type argument. We establish a similar result for the viscous nonlocal Cahn-Hilliard equation with singular (e.g., logarithmic) potential. In this case the validity of the so-called separation property is crucial. We also discuss the convergence of a solution to a single stationary state. The separation property in the nonviscous case is known to hold when the mobility degenerates at the pure phases in a proper way and the potential is of logarithmic type. Thus, the existence of an exponential attractor can be proven in this case as well

    Flexural behaviour of RC one-way slabs reinforced using PAN based carbon textile grid

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    Textile reinforced mortar (TRM) is mainly used for strengthening of existing structural members whereas, on the other hand Textile reinforced concrete (TRC) is a technology implied in construction of new members for enhancing the structural behaviour. Application of TRM on the tension zone of the reinforced concrete (RC) slabs to improve the flexural capacity has been investigated by many researchers in the past. However, the effectiveness of textile fabrics, used as internal reinforcement in the RC slab (TRC technology) needs to be studied. The paper, therefore, presents the experimental research conducted on three one-way RC slabs specimens reinforced using textile grid. An innovative Polyacrylonitrile (PAN) based carbon textile grid was used as internal reinforcement in combination with the steel bars. Two textile-reinforced RC slabs having one and two layers of textile grid (SRC + 1T and SRC + 2T respectively) and one reference slab (SRC) was fabricated to investigate the flexural behaviour under a four-point loading system. The internal textile reinforcement layer(s) was confirmed to be effective, particularly in terms of improving the cracking load, ductility, deformability and toughness. The material ductility of SRC + 1T and SRC + 2T slabs were increased by 41% and 44% compared to SRC slab. Also, the deformability ratio was found to be greater than 4, indicating a ductile failure of textile-reinforced slabs. Further, based on the load-deflection relation, moment-curvature curves were derived. Moreover, these curves were also developed using Eurocode two prediction model. The experimental and the predicted moment-curvature curves showed good agreement

    Cell-Type Specific Roles for PTEN in Establishing a Functional Retinal Architecture

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    BACKGROUND: The retina has a unique three-dimensional architecture, the precise organization of which allows for complete sampling of the visual field. Along the radial or apicobasal axis, retinal neurons and their dendritic and axonal arbors are segregated into layers, while perpendicular to this axis, in the tangential plane, four of the six neuronal types form patterned cellular arrays, or mosaics. Currently, the molecular cues that control retinal cell positioning are not well-understood, especially those that operate in the tangential plane. Here we investigated the role of the PTEN phosphatase in establishing a functional retinal architecture. METHODOLOGY/PRINCIPAL FINDINGS: In the developing retina, PTEN was localized preferentially to ganglion, amacrine and horizontal cells, whose somata are distributed in mosaic patterns in the tangential plane. Generation of a retina-specific Pten knock-out resulted in retinal ganglion, amacrine and horizontal cell hypertrophy, and expansion of the inner plexiform layer. The spacing of Pten mutant mosaic populations was also aberrant, as were the arborization and fasciculation patterns of their processes, displaying cell type-specific defects in the radial and tangential dimensions. Irregular oscillatory potentials were also observed in Pten mutant electroretinograms, indicative of asynchronous amacrine cell firing. Furthermore, while Pten mutant RGC axons targeted appropriate brain regions, optokinetic spatial acuity was reduced in Pten mutant animals. Finally, while some features of the Pten mutant retina appeared similar to those reported in Dscam-mutant mice, PTEN expression and activity were normal in the absence of Dscam. CONCLUSIONS/SIGNIFICANCE: We conclude that Pten regulates somal positioning and neurite arborization patterns of a subset of retinal cells that form mosaics, likely functioning independently of Dscam, at least during the embryonic period. Our findings thus reveal an unexpected level of cellular specificity for the multi-purpose phosphatase, and identify Pten as an integral component of a novel cell positioning pathway in the retina
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