920 research outputs found
Situating organizational action: the relational sociology of organizations
This paper advances a relational sociology of organization that seeks to address concerns over how organizational action is understood and situated. The approach outlined here is one which takes ontology seriously and requires transparency and consistency of position. It aims at causal explanation over description and/or prediction and seeks to avoid pure voluntarism or structural determinism in such explanation. We advocate relational analysis that recognizes and engages with connections within and across organization and with wider contexts. We develop this argument by briefly reviewing three promising approaches: relational pragmatism, the social theorizing of Bourdieu and critical realism, highlighting their ontological foundations, some similarities and differences and surfacing some methodological issues. Our purpose is to encourage analysis that explores the connections within and between perspectives and theoretical positions. We conclude that the development of the field of organization theory will benefit from self conscious and reflexive engagement and debate both within and across our various research positions and traditions only if such debates are conducted on the basis of holistic evaluations and interpretations that recognize (and value) difference
Guide to the use of Mariner images
Planetary imaging from unmanned spacecraft, almost exclusively done by digital systems, is examined. The Mars Mariner 9 television camera, representative of such systems, is considered. Each image consists of 700 lines, each containing 832 picture elements, or pixels. Each pixel contains nine binary bits of information capable of displaying 512 discrete brightness levels. Several problems inherent in television systems are discussed. These include nonuniform target response, residual images, noise, and blemishes. These defects can be removed to some extent by decalibration of the image. The final product is geometrically corrected for camera distortion and photometrically corrected. Several versions of the decalibrated images are available. The most generally useful are the geometrically corrected images with enhanced contrast. The Mariner 10 imaging of Mercury is briefly discussed
The limits of process: On (re)reading Henri Bergson
This article offers a reading of the work of Henri Bergson as it pertains to organizations through the lens of ideas drawn from critical realism. It suggests an alternative to interpretations based on a stark division between process and realist perspectives. Much of the existing literature presents a rather partial view of Bergson’s work. A review suggests some interesting parallels with themes in critical realism, notably the emergence of mind. Critical realism has a focus on process at its heart, but is also concerned with how the products of such processes become stabilized and form the conditions for action. This suggests that attention might usefully be paid to the relationship between organizational action and the sedimented practices grouped under the heading of ‘routines’. More attention to Bergson’s account of the relationship between instinct, intuition and intelligence provides a link to the social character of thought, something which can be mapped on to Archer’s work on reflexivity and the ‘internal conversation’. This suggests that our analyses need to pay attention to both memory and history, to building and dwelling, rather than the one-sided focus found in some process theory accounts
Health utilities and costs for neuromyelitis optica spectrum disorder
Neuromyelitis optica spectrum disorder (NMOSD) is a rare, neurological disease that places a significant burden on patients, their carers, and healthcare systems
Single-chain factor XII exhibits activity when complexed to polyphosphate
© 2014 The Authors. Journal of Thrombosis and Haemostasis published by Wiley Periodicals, Inc. on behalf of International Society on Thrombosis and Haemostasis.Peer reviewedPublisher PD
Interleukin-4 deficiency enhances Th1 responses and crescentic glomerulonephritis in mice
Interleukin-4 deficiency enhances Th1 responses and crescentic glomerulonephritis in mice. Evidence suggests that crescentic glomerulonephritis (GN) is due to T helper cell 1 (Th1) directed delayed-type hypersensitivity (DTH)-like injury. As endogenous interleukin (IL)-4, (the pivotal cytokine in Th2 responses) may attenuate Th1 responses in this disease, we compared the development of crescentic GN, induced by a planted antigen, in mice genetically deficient in IL-4 (IL-4−/−) with disease in normal mice (IL-4+/+). IL-4−/− mice developed more severe GN with increased renal impairment (CCr 35 ± 7 μl/min vs. 133 ± 14 μl/min, P < 0.002) and crescent formation (55.7 ± 8.4% vs. 4.9 ± 1.2%, P < 0.002). This was associated with increased glomerular fibrin deposition, glomerular CD4+ T cell infiltration and macrophage recruitment. Systemically, IL-4−/− mice showed an increased antigen specific Th1 response indicated by increased skin DTH, and increased IgG3 and IgG2b. Decreased IgG1 levels indicated a reduced Th2 response. These results demonstrate a protective role for endogenous IL-4 in crescentic GN. They show that IL-4 deficiency promotes crescentic glomerular injury and amplifies local and systemic Th1 responses. They support the hypothesis that crescent formation results from Th1 immune responses to antigens in the glomerulus
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Imaging glutathione depletion in the rat brain using ascorbate-derived hyperpolarized MR and PET probes.
Oxidative stress is a critical feature of several common neurologic disorders. The brain is well adapted to neutralize oxidative injury by maintaining a high steady-state concentration of small-molecule intracellular antioxidants including glutathione in astrocytes and ascorbic acid in neurons. Ascorbate-derived imaging probes for hyperpolarized 13C magnetic resonance spectroscopy and positron emission tomography have been used to study redox changes (antioxidant depletion and reactive oxygen species accumulation) in vivo. In this study, we applied these imaging probes to the normal rat brain and a rat model of glutathione depletion. We first studied hyperpolarized [1-13C]dehydroascorbate in the normal rat brain, demonstrating its robust conversion to [1-13C]vitamin C, consistent with rapid transport of the oxidized form across the blood-brain barrier. We next showed that the kinetic rate of this conversion decreased by nearly 50% after glutathione depletion by diethyl maleate treatment. Finally, we showed that dehydroascorbate labeled for positron emission tomography, namely [1-11C]dehydroascorbate, showed no change in brain signal accumulation after diethyl maleate treatment. These results suggest that hyperpolarized [1-13C]dehydroascorbate may be used to non-invasively detect oxidative stress in common disorders of the brain
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Imaging Active Infection in vivo Using D-Amino Acid Derived PET Radiotracers.
Occult bacterial infections represent a worldwide health problem. Differentiating active bacterial infection from sterile inflammation can be difficult using current imaging tools. Present clinically viable methodologies either detect morphologic changes (CT/ MR), recruitment of immune cells (111In-WBC SPECT), or enhanced glycolytic flux seen in inflammatory cells (18F-FDG PET). However, these strategies are often inadequate to detect bacterial infection and are not specific for living bacteria. Recent approaches have taken advantage of key metabolic differences between prokaryotic and eukaryotic organisms, allowing easier distinction between bacteria and their host. In this report, we exploited one key difference, bacterial cell wall biosynthesis, to detect living bacteria using a positron-labeled D-amino acid. After screening several 14C D-amino acids for their incorporation into E. coli in culture, we identified D-methionine as a probe with outstanding radiopharmaceutical potential. Based on an analogous procedure to that used for L-[methyl-11C]methionine ([11C] L-Met), we developed an enhanced asymmetric synthesis of D-[methyl-11C]methionine ([11C] D-Met), and showed that it can rapidly and selectively differentiate both E. coli and S. aureus infections from sterile inflammation in vivo. We believe that the ease of [11C] D-Met radiosynthesis, coupled with its rapid and specific in vivo bacterial accumulation, make it an attractive radiotracer for infection imaging in clinical practice
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