8,582 research outputs found

    Intersectionality, Resistance, and History-Making: A Conversation Between Carolyn D'Cruz, Ruth DeSouza, Samia Khatun, and Crystal McKinnon, Facilitated by Jordana Silverstein

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    A good, solid, history-writing practice is one which, I think, shakes people's ideas of the world and their place in it, compelling them to imagine new social, cultural and political formations which can provide an account of life. Kimberle Crenshaw's development of the term 'intersectionality', and the ways it has been taken up by people of colour within the academy internationally, as well as by activists, provides one example of such imaginative work. Because when you spend some time in the Australian History academic scene, at conferences, in departments, talking to other academics, it's quickly noticeable that one of its key features is its hegemonic whiteness. Even in those spaces that aspire to avoid whiteness, it's inescapable, visible daily, as well as in the themes at conferences, the keynote speakers chosen, the food served, the knowledge shared. When it came time for the Australian Women's History Network conference in 2016, which carried the theme of 'Intersections in History', it felt like this could provide a way of modelling a different kind of Australian academic History space. What would a conversation look like that skipped over the presence of white Anglo Australians, I wondered? What if we just left them to the side? What if we gathered together some of the smartest, sharpest thinkers in Melbourne academia, and spoke amongst ourselves, coming up with new formations of knowledge? And so we did: Crystal, Samia, Ruth and Carolyn gathered together, I asked them some questions, and we had a conversation that, in numerous ways, challenged white hegemonies. We've recreated some of that conversation below, as a way of continuing to think together, and to find new ways of making this thinking public

    Colour Text Segmentation in Web Images Based on Human Perception

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    There is a significant need to extract and analyse the text in images on Web documents, for effective indexing, semantic analysis and even presentation by non-visual means (e.g., audio). This paper argues that the challenging segmentation stage for such images benefits from a human perspective of colour perception in preference to RGB colour space analysis. The proposed approach enables the segmentation of text in complex situations such as in the presence of varying colour and texture (characters and background). More precisely, characters are segmented as distinct regions with separate chromaticity and/or lightness by performing a layer decomposition of the image. The method described here is a result of the authors’ systematic approach to approximate the human colour perception characteristics for the identification of character regions. In this instance, the image is decomposed by performing histogram analysis of Hue and Lightness in the HLS colour space and merging using information on human discrimination of wavelength and luminance

    Caring for grandchildren and intergenerational support in rural China: a gendered extended family perspective

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    This investigation examines how support from adult children is affected by their parents’ involvement in grandchild care. Instead of focusing on dyadic interactions, we adopt a gendered extended family perspective to examine how financial and emotional support from children was influenced when their siblings received help with child care from their elder parents. The data were from a two-wave (2001, 2003) longitudinal study of 4,791 parent–child dyads with 1,162 parents, aged 60 and older, living in rural areas of Anhui Province, China. Random effects regression showed that emotional support from both sons and daughters was strengthened when parents provided more child care for their other adult children; in addition, daughters were more emotionally responsive than sons under this situation. Concerning dyadic parent–child relationships, daughter and sons increased their financial support, and sons increased their emotional support when they themselves received help with child care from parents. We suggest taking a gendered extended family perspective when studying intergenerational relationships in rural China

    Localization of Bulk Form Fields on Dilatonic Domain Walls

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    We study the localization properties of bulk form potentials on dilatonic domain walls. We find that bulk form potentials of any ranks can be localized as form potentials of the same ranks or one lower ranks, for any values of the dilaton coupling parameter. For large enough values of the dilaton coupling parameter, bulk form potentials of any ranks can be localized as form potentials of both the same ranks and one lower ranks.Comment: 9 pages, LaTeX, reference adde

    Receptors for C3b and C3bi promote phagocytosis but not the release of toxic oxygen from human phagocytes

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    We have measured the release of H2O2 from granulocytes, monocytes, and macrophages during spreading on ligand-coated culture surfaces. While IgG-coated surfaces stimulate vigorous release of H2O2, neither C3b- nor C3bi-coated surfaces promoted appreciable release of H2O2 despite full ligation of C3b and C3bi receptors. We also measured release of H2O2 from cultured monocytes spreading on surfaces coated with both fibronectin and C3. Under such circumstances, the C3 receptors elicit a strong phagocytic response, but no H2O2 release was recorded. We conclude that the C3b and C3bi receptors of monocytes and granulocytes do not signal the generation of toxic oxygen intermediates from these cells

    Tumor-promoting phorbol esters stimulate C3b and C3b' receptor-mediated phagocytosis in cultured human monocytes

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    Monocytes were isolated in high yield (approximately 80%) and purity (greater than 90%) by Percoll gradient centrifugation and incubated in Teflon culture vessels. Using this culture method, we routinely recovered 80% of the cells originally placed into culture. Studies of the C3b and C3b' receptors of these monocytes showed that the function of both receptors could be dramatically altered by treating the cells with tumor-promoting phorbol esters. Both C3b and C3b' receptors of human monocytes efficiently mediate attachment of erythrocytes coated with the corresponding ligands, but do not promote their ingestion. However, monocytes treated with phorbol myristate acetate (PMA) or phorbol didecanoate ingest C3b- and C3b'-coated erythrocytes. Phorbol esters that are inactive as tumor promoters do not stimulate C3 receptor-mediated phagocytosis. The ability of monocytes to respond to PMA by activation of C3 receptors is developmentally regulated. Freshly isolated monocytes do not take up C3b- or C3b'-coated erythrocytes in response to PMA, but after 3 d of culture they show strong PMA-stimulated uptake. The stimulatory effect of PMA on monocyte C3b and C3b' receptor function occurs within minutes, is stable for hours, is cycloheximide insensitive, and can be inhibited with colchicine. Several lines of evidence indicates that phagocytosis of C3b or C3b'-coated erythrocytes is specifically mediated by the monocytes' C3b and C3b' receptors. First, erythrocytes attached to monocytes with concanavalin A are not ingested when the monocytes are treated with PMA. Second, monocytes plated on IgG-bearing substrates lose Fc receptor activity on their nonadherent surfaces but retain the capacity to ingest C3b- or C3b'-coated erythrocytes after PMA treatment. Third, PMA-treated monocytes plated on C3b-coated surfaces lose C3b receptor activity on their nonadherent surfaces but retain the capacity to ingest C3b'-coated erythrocytes. Conversely, PMA-treated monocytes plated on C3b'-coated surfaces show reduced C3b' receptors activity on their nonadherent surfaces but retain the capacity to ingest C3b-coated erythrocytes

    Study of resonance light scattering for remote optical probing

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    Enhanced scattering and fluorescence processes in the visible and UV were investigated which will enable improved remote measurements of gas properties. The theoretical relationship between scattering and fluorescence from an isolated molecule in the approach to resonance is examined through analysis of the time dependence of re-emitted light following excitation of pulsed incident light. Quantitative estimates are developed for the relative and absolute intensities of fluorescence and resonance scattering. New results are obtained for depolarization of scattering excited by light at wavelengths within a dissociative continuum. The experimental work was performed in two separate facilities. One of these utilizes argon and krypton lasers, single moded by a tilted etalon, and a 3/4 meter double monochromator. This facility was used to determine properties of the re-emission from NO2, I2 and O3 excited by visible light. The second facility involves a narrow-line dye laser, and a 3/4 meter single monochromator. The dye laser produces pulsed light with 5 nsec pulse duration and 0.005 nm spectral width

    Simple de Sitter Solutions

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    We present a framework for de Sitter model building in type IIA string theory, illustrated with specific examples. We find metastable dS minima of the potential for moduli obtained from a compactification on a product of two Nil three-manifolds (which have negative scalar curvature) combined with orientifolds, branes, fractional Chern-Simons forms, and fluxes. As a discrete quantum number is taken large, the curvature, field strengths, inverse volume, and four dimensional string coupling become parametrically small, and the de Sitter Hubble scale can be tuned parametrically smaller than the scales of the moduli, KK, and winding mode masses. A subtle point in the construction is that although the curvature remains consistently weak, the circle fibers of the nilmanifolds become very small in this limit (though this is avoided in illustrative solutions at modest values of the parameters). In the simplest version of the construction, the heaviest moduli masses are parametrically of the same order as the lightest KK and winding masses. However, we provide a method for separating these marginally overlapping scales, and more generally the underlying supersymmetry of the model protects against large corrections to the low-energy moduli potential.Comment: 37 pages, harvmac big, 4 figures. v3: small correction

    A Phase Transition between Small and Large Field Models of Inflation

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    We show that models of inflection point inflation exhibit a phase transition from a region in parameter space where they are of large field type to a region where they are of small field type. The phase transition is between a universal behavior, with respect to the initial condition, at the large field region and non-universal behavior at the small field region. The order parameter is the number of e-foldings. We find integer critical exponents at the transition between the two phases.Comment: 21 pages, 8 figure

    Tyrosine phosphorylation is required for Fc receptor-mediated phagocytosis in mouse macrophages

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    Although Fc receptor-mediated phagocytosis is accompanied by a variety of transmembrane signaling events, not all signaling events are required for particle ingestion. For example, Fc receptor-mediated phagocytosis in mouse inflammatory macrophages (Di Virgilio, F., B. C. Meyer, S. Greenberg, and S. C. Silverstein. 1988. J. Cell Biol. 106:657; Greenberg, S., J. El Khoury, F. Di Virgilio, and S. C. Silverstein. 1991. J. Cell Biol. 113:757) and neutrophils (Della Bianca, V., M. Grzeskowiak, and F. Rossi. 1990. J. Immunol. 144:1411) occurs in the absence of cytosolic calcium transients. We sought to identify transmembrane signaling events that are essential for phagocytosis. Here we show that tyrosine phosphorylation is an early event after Fc receptor ligation in mouse inflammatory macrophages, and that the formation of tyrosine phosphoproteins coincides temporally with the appearance of F-actin beneath phagocytic cups. The distribution of tyrosine phosphoproteins that accumulated beneath phagocytic cups was punctate and corresponded to areas of high ligand density on the surface of the antibody-coated red blood cells, which provided the phagocytic stimulus. A tyrosine kinase inhibitor, genistein, but not several inhibitors of protein kinase C, blocked the appearance of tyrosine phosphoproteins as assessed by immunofluorescence, the focal accumulation of F-actin beneath immunoglobulin G-opsonized particles, and the ingestion of these particles as well. We suggest that tyrosine phosphorylation is a critical signaling event that underlies Fc receptor-mediated phagocytosis in mouse macrophages, and is necessary for the engulfment per se
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