41 research outputs found

    Natural cassava drying systems

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    Artificial cassava drying systems

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    Sensing Art and Artifacts: Explorations in Sensory Museology

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    This article proposes a sensory studies methodology for the interpretation of museum objects. The proposed method unfolds in two phases: virtual encounter via an on-line catalog and actual exposure in the context of a handling workshop. In addition to exploring the Ă©cart between image and object, the “Sensing Art and Artifacts” exercise articulates a framework for arriving at a multisensory, cross-cultural, interactive understanding of aesthetic value. The case studies presented here involve four objects from the collection of the Hunterian Museum as sensed and interpreted by scholars of psychology, philosophy, sociology, and anthropology. It is proposed that aesthetic judgment in the expanded (cross-cultural) sense contemplated here involves apprehending the museum object through multiple sensory modalities in place of the conventional Western ïŹxation on visible form

    The genome-defence gene Tex19.1 suppresses LINE-1 retrotransposons in the placenta and prevents intra-uterine growth retardation in mice

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    DNA methylation plays an important role in suppressing retrotransposon activity in mammalian genomes, yet there are stages of mammalian development where global hypomethylation puts the genome at risk of retrotransposition-mediated genetic instability. Hypomethylated primordial germ cells appear to limit this risk by expressing a cohort of retrotransposon-suppressing genome-defence genes whose silencing depends on promoter DNA methylation. Here, we investigate whether similar mechanisms operate in hypomethylated trophectoderm-derived components of the mammalian placenta to couple expression of genome-defence genes to the potential for retrotransposon activity. We show that the hypomethylated state of the mouse placenta results in activation of only one of the hypomethylation-sensitive germline genome-defence genes: Tex19.1. Tex19.1 appears to play an important role in placenta function as Tex19.1(−/−) mouse embryos exhibit intra-uterine growth retardation and have small placentas due to a reduction in the number of spongiotrophoblast, glycogen trophoblast and sinusoidal trophoblast giant cells. Furthermore, we show that retrotransposon mRNAs are derepressed in Tex19.1(−/−) placentas and that protein encoded by the LINE-1 retrotransposon is upregulated in hypomethylated trophectoderm-derived cells that normally express Tex19.1. This study suggests that post-transcriptional genome-defence mechanisms are operating in the placenta to protect the hypomethylated cells in this tissue from retrotransposons and suggests that imbalances between retrotransposon activity and genome-defence mechanisms could contribute to placenta dysfunction and disease

    Deletion of the Pluripotency-Associated Tex19.1 Gene Causes Activation of Endogenous Retroviruses and Defective Spermatogenesis in Mice

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    As genetic information is transmitted through successive generations, it passes between pluripotent cells in the early embryo and germ cells in the developing foetus and adult animal. Tex19.1 encodes a protein of unknown function, whose expression is restricted to germ cells and pluripotent cells. During male spermatogenesis, Tex19.1 expression is highest in mitotic spermatogonia and diminishes as these cells differentiate and progress through meiosis. In pluripotent stem cells, Tex19.1 expression is also downregulated upon differentiation. However, it is not clear whether Tex19.1 has an essential function in germ cells or pluripotent stem cells, or what that function might be. To analyse the potential role of Tex19.1 in pluripotency or germ cell function we have generated Tex19.1−/− knockout mice and analysed the Tex19.1−/− mutant phenotype. Adult Tex19.1−/− knockout males exhibit impaired spermatogenesis. Immunostaining and histological analysis revealed defects in meiotic chromosome synapsis, the persistence of DNA double-strand breaks during meiosis, and a loss of post-meiotic germ cells in the testis. Furthermore, expression of a class of endogenous retroviruses is upregulated during meiosis in the Tex19.1−/− testes. Increased transposition of endogenous retroviruses in the germline of Tex19.1−/− mutant mice, and the concomitant increase in DNA damage, may be sufficient to disrupt the normal processes of recombination and chromosome synapsis during meiosis and cause defects in spermatogenesis. Our results suggest that Tex19.1 is part of a specialised mechanism that operates in the germline to repress transposable genetic elements and maintain genomic stability through successive generations

    Nature of plant viruses

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    ReprintsLacks table of contents and abstractIncludes bibliographical references.7 v. (30 parts) :Title page, preface and list of publs submitted only. The complete thesis in print form is available from the University Library.Thesis (D.Sc.)--University of Adelaide, 194

    A rapid electrometric method for determining the chloride content of soils

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