583 research outputs found

    Three essays on the performance of earnings forecasts, bankruptcy predictions and textual analysis

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    In summary, Chapter 2 of my thesis finds that quantitative information from interim financial earnings disclosures fundamentally improves the earnings forecast accuracy of mechanical models and levels the playing field when comparing model forecasts to analyst forecasts. Similarly, quantitative financial disclosure information is a key input in most bankruptcy prediction models. Using web crawling techniques to aggregate bankruptcy information of German companies, Chapter 3 shows that the reliability of widely used bankruptcy prediction models is determined by the quality of the underlying bankruptcy data. Accordingly, bankruptcy prediction models can be improved by collecting accurate bankruptcy data and discarding incorrect information. Complementary, Chapter 4 applies a new perspective to information provided in corporate disclosures by examining qualitative or textual content. This section introduces a novel framework focusing on analysis of the textual content of annual reports. Using the immediacy of market reactions and investor responses to textual information enables quantifying the qualitative content of financial disclosures

    Correlation of X-Ray CT Measurements to Shear Strength in Pultruded Composite Materials

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    Pultrusion is an emerging, economical manufacturing process for composite structures. In a pultrusion system, the composite tapes and fabrics are loaded onto a creel, and the materials are fed into a preform (or shaper), along with any fillers that may be needed. If the fiber is not yet preimpregnated with resin, it is run through a resin bath or resin is injected into the die the material is about to enter. The composite is pulled through the heated die and then cut from the system to produce either a fully or partially cured product. This handleable part is then placed in an autoclave for final cure. A number of variables go into the pultrusion process, including the type of fibers, the resin matrix material, pull rate and cure temperature. Destructive testing, such as shear testing of small sections, is the normal method for assessing the quality of the pultrusion manufacturing product. During manufacture, this cannot be performed on the actual product to be used but only on near neighbor test coupons. This can be time consuming, costly, and part of the product is destroyed

    Sensitive enzymatic quantification of 5-hydroxymethylcytosine in genomic DNA

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    The recent discovery of genomic 5-hydroxymethylcytosine (hmC) and mutations affecting the respective Tet hydroxylases in leukemia raises fundamental questions about this epigenetic modification. We present a sensitive method for fast quantification of genomic hmC based on specific transfer of radiolabeled glucose to hmC by a purified glucosyltransferase. We determined hmC levels in various adult tissues and differentiating embryonic stem cells and show a correlation with differential expression of tet genes

    Inflammation-induced reactive nitrogen species cause proteasomal degradation of dimeric peroxiredoxin-1 in a mouse macrophage cell line

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    Peroxiredoxin 1 (PRDX1) is an antioxidant enzyme that, when secreted, can act as a proinflammatory signal. Here we studied the regulation of intracellular PRDX1 by lipopolysaccharide (LPS) and interferon-gamma (IFN-γ) in the RAW 264.7 mouse macrophage cell line. While LPS or IFN-γ alone did not affect PRDX1 protein levels, their combination led to an almost complete loss of the PRDX1 dimer. This was likely mediated by the increased production of nitric oxide (NO) as it was reversed by the NO synthase inhibitor L-N-methylarginine (L-NMMA), while a NO-releasing agent decreased PRDX1 levels. Inhibition of the proteasome with MG132 also prevented the loss of the PRDX1 dimer, suggesting that the decrease is due to a NO-activated proteasomal degradation pathway. By contrast with the decrease in protein levels, LPS increased PRDX1 mRNA and this effect was amplified by IFN-γ. Two other Nrf2 target genes, thioredoxin reductase (TXNRD1) and haem oxygenase (HMOX1), were also induced by LPS but IFN-γ did not increase their expression further. This study shows that inflammation differentially regulates PRDX1 at the levels of protein stability and gene expression, and that NO plays a key role in this mechanism.By contrast with the decrease in protein levels, LPS increased PRDX1 mRNA and this effect was amplified by IFNγ. Two other Nrf2 target genes, thioredoxin reductase (TXNRD1) and heme oxygenase (HMOX1), were also induced by LPS but IFNγ did not increase their expression further. This study shows that inflammation differentially regulates PRDX1 at the levels of protein stability and gene expression, and that NO plays a key role in this mechanism. For illustration see published version

    Stimulated stromal cells induce gamma-globin gene expression in erythroid cells via nitric oxide production

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    Objective. We have previously shown that nitric oxide (NO) is involved in the hydroxyurea-induced increase of gamma-globin gene expression in cultured human erythroid progenitor cells and that hydroxyurea increases NO production in endothelial cells via endothelial NO synthase (NOS). We have now expanded those studies to demonstrate that stimulation of gamma-globin gene expression is also mediated by NOS induction in stromal cells within the bone marrow microenvironment. Materials and Methods. Using NO analyzer, we measured NO production in endothelial and macrophage cell cultures. In coculture studies of erythroid and stromal cells, we measured globin gene expression during stimulation by NO induers. Results. Hydroxyurea (30 - 100 mu M) induced NOS-dependent production of NO in human macrophages (up to 1.2 mu M). Coculture studies of human macrophages with erythroid progenitor cells also resulted in induction of gamma-globin mRNA expression (up to threefold) in the presence of hydroxyurea. NOS-dependent stimulation of NO by lipopolysaccharide (up to 0.6 mu M) has been observed in human macrophages. We found that lipopolysaccharide and interferon-gamma together increased gamma-globin gene expression (up to twofold) in human macrophage/erythroid cell cocultures. Coculture of human bone marrow endothelial cells with erythroid progenitor cells also induced gamma-globin mRNA expression (2.4-fold) in the presence of hydroxyurea (40 mu M). Conclusion. These results demonstrate an arrangement by which NO and fetal hemoglobin inducers may stimulate globin genes in erythroid cells via the common paracrine effect of bone marrow stromal cells

    Impaired psychological recovery in the elderly after the Niigata-Chuetsu Earthquake in Japan:a population-based study

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    BACKGROUND: An earthquake measuring 6.8 on the Richter scale struck the Niigata-Chuetsu region of Japan at 5.56 P.M. on the 23rd of October, 2004. The earthquake was followed by sustained occurrence of numerous aftershocks, which delayed reconstruction of community lifelines. Even one year after the earthquake, 9,160 people were living in temporary housing. Such a devastating earthquake and life after the earthquake in an unfamiliar environment should cause psychological distress, especially among the elderly. METHODS: Psychological distress was measured using the 12-item General Health Questionnaire (GHQ-12) in 2,083 subjects (69% response rate) who were living in transient housing five months after the earthquake. GHQ-12 was scored using the original method, Likert scoring and corrected method. The subjects were asked to assess their psychological status before the earthquake, their psychological status at the most stressful time after the earthquake and their psychological status at five months after the earthquake. Exploratory and confirmatory factor analysis was used to reveal the factor structure of GHQ12. Multiple regression analysis was performed to analyze the relationship between various background factors and GHQ-12 score and its subscale. RESULTS: GHQ-12 scores were significantly elevated at the most stressful time and they were significantly high even at five months after the earthquake. Factor analysis revealed that a model consisting of two factors (social dysfunction and dysphoria) using corrected GHQ scoring showed a high level of goodness-of-fit. Multiple regression analysis revealed that age of subjects affected GHQ-12 scores. GHQ-12 score as well as its factor 'social dysfunction' scale were increased with increasing age of subjects at five months after the earthquake. CONCLUSION: Impaired psychological recovery was observed even at five months after the Niigata-Chuetsu Earthquake in the elderly. The elderly were more affected by matters relating to coping with daily problems
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