337 research outputs found

    Brilliance of a fire: innocence, experience and the theory of childhood

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    This essay offers an extensive rehabilitation and reappraisal of the concept of childhood innocence as a means of testing the boundaries of some prevailing constructions of childhood. It excavates in detail some of the lost histories of innocence in order to show that these are more diverse and more complex than established and pejorative assessments of them conventionally suggest. Recovering, in particular, the forgotten pedigree of the Romantic account of the innocence of childhood underlines its depth and furnishes an enriched understanding of its critical role in the coming of mass education - both as a catalyst of social change and as an alternative measure of the child-centeredness of the institutions of public education. Now largely and residually confined to the inheritance of nursery education, the concept of childhood innocence, and the wider Romantic project of which it is an element, can help question the assumptions underpinning modern, competence-centred philosophies of childhood

    Pure Framed Braids and 3-Manifolds.

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    This dissertation looks at representations of framed pure braids and compact orientable three manifolds. A representation, \Phi:Z\sp{n}\oplus P\sb{n}\to \Gamma\sb{n}, is constructed from the framed pure braid group on n strands to the mapping class group on a surface of genus n. The representation is used to obtain a presentation of the fundamental group. The representation, like that of (M-P), is compatible with Heegaard and Surgery descriptions. An algorithm is presented for transforming mapping class group elements to a stably equivalent pure framed braid, under the correspondence given by the representation. A geometric description, using the representation, is given for multiplication in a subgroup of a central extension to the mapping class group coming from (A). A question of providing a group representation development for Witten\u27s three manifold invariant is explored. The result is negative, except for a restricted case of pure framed braids

    Double Bark Thickness Estimation Models of Common European Broadleaved Species for Harvester Timber Volume Estimation in Czechia

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    The share of the annual volume of harvester-produced timber in Czech forest bioeconomy has increased in the last decades. To estimate under-bark timber volume, harvester systems allow choosing between two different bark deduction models – diameter band (DBM) and linear model. However, linear models were not calibrated for the conditions of Czech forestry. Therefore, the objective of this research was to develop, for local conditions in Czechia, linear functions for estimating the double bark thickness of two groups of broadleaved species (beech and oak) and to test their viability based on real harvest data. To create the linear functions, official Czech cubing tables were used. Data from real harvests were gathered from fifteen harvesters. A sample containing 4995 logs belonging to the beech group was analyzed using descriptive statistics and the Paired Wilcoxon tests. The mean double bark thickness for beech group was 15.1 mm (polynomial and linear model). For oak group, it was 15.48 mm (polynomial) or 15.49 mm (linear). The results of real harvests for beech group revealed that the mean double bark thickness estimated by the polynomial function was 7.08 mm. The linear function estimates were closer to the value estimated by the polynomial (6.84 mm) than DBM estimates (6.68 mm). Therefore, we can state that the newly developed linear models can be used in fully mechanized harvesting instead of manual bark deduction methods in Czechia

    Evaluation of stress loading for logging truck drivers by monitoring changes in muscle tension during a work shift

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    Our research aimed to quantify and evaluate the stress loading of drivers by monitoring the loading of the radial extensor muscle at the wrist joint (musculus extensor carpi radialis) when they drove different types of timber trucks. We monitored changes in the electric potential of skeletal muscles with electromyographic measurements and measurements of changes of heart rate using the Biofeedback 2000 x-pert device. The drivers were observed throughout their work shifts during normal operation of logging trucks and logging trucks with trailers. As a reference, muscle load was measured when driving a passenger car. We evaluated the normality of the measured data and obtained descriptive statistics from the individual measurements. The differences in stress load associated with driving the different types of vehicles increased whilst driving on lower-class roads. Results showed a high stress load for drivers of loaded vehicles when driving on narrow roads. It was more challenging to control a loaded logging truck with a trailer than driving a logging truck, with the difference in muscular loading reaching 22.5%. Driving a logging truck with a trailer produced 46.5% more muscle loading compared to driving a loaded passenger car. For preventive health and safety reasons, it would be reasonable to alternate between drivers when operating various vehicles, thus minimizing the development of possible health issues

    Quantitative Proteomics Reveals that the OGT Interactome is Remodeled in Response to Oxidative Stress

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    The dynamic modification of specific serine and threonine residues of intracellular proteins by O-linked N-acetylβ-D-glucosamine (O-GlcNAc) mitigates injury and promotes cytoprotection in a variety of stress models. The O-GlcNAc transferase (OGT) and the O-GlcNAcase are the sole enzymes that add and remove O-GlcNAc, respectively, from thousands of substrates. It remains unclear how just two enzymes can be specifically controlled to affect glycosylation of target proteins and signaling pathways both basally and in response to stress. Several lines of evidence suggest that protein interactors regulate these responses by affecting OGT and O-GlcNAcase activity, localization, and substrate specificity. To provide insight into the mechanisms by which OGT function is controlled, we have used quantitative proteomics to define OGT's basal and stress-induced interactomes. OGT and its interaction partners were immunoprecipitated from OGT WT, null, and hydrogen peroxide-treated cell lysates that had been isotopically labeled with light, medium, and heavy lysine and arginine (stable isotopic labeling of amino acids in cell culture). In total, more than 130 proteins were found to interact with OGT, many of which change their association upon hydrogen peroxide stress. These proteins include the major OGT cleavage and glycosylation substrate, host cell factor 1, which demonstrated a time-dependent dissociation after stress. To validate less well-characterized interactors, such as glyceraldehyde 3-phosphate dehydrogenase and histone deacetylase 1, we turned to parallel reaction monitoring, which recapitulated our discovery-based stable isotopic labeling of amino acids in cell culture approach. Although the majority of proteins identified are novel OGT interactors, 64% of them are previously characterized glycosylation targets that contain varied domain architecture and function. Together these data demonstrate that OGT interacts with unique and specific interactors in a stress-responsive manner.</p

    Stress-induced O-GlcNAcylation: an adaptive process of injured cells

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    In the 30 years, since the discovery of nucleocytoplasmic glycosylation, O-GlcNAc has been implicated in regulating cellular processes as diverse as protein folding, localization, degradation, activity, post-translational modifications, and interactions. The cell co-ordinates these molecular events, on thousands of cellular proteins, in concert with environmental and physiological cues to fine-tune epigenetics, transcription, translation, signal transduction, cell cycle, and metabolism. The cellular stress response is no exception: diverse forms of injury result in dynamic changes to the O-GlcNAc subproteome that promote survival. In this review, we discuss the biosynthesis of O-GlcNAc, the mechanisms by which O-GlcNAc promotes cytoprotection, and the clinical significance of these data
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