Automatischer Aufbau eines multilingualen Thesaurus durch Extraktion semantischer und lexikalischer Relationen aus der Wikipedia

Die vorliegende Diplomarbeit beschreibt und analysiert Methoden, um aus den Datenbeständen der Wikipedia in verschiedenen Sprachen einen multilingualen Thesaurus zu erstellen. Dabei sollen insbesondere die Beziehungen zwischen Termen (Wörtern, Wortformen, Phrasen) zu sprachunabhängigen Konzepten extrahiert werden sowie die Beziehungen zwischen solchen Konzepten, speziell Beziehungen der Über- bzw. Unterordnung (Subsumtion) sowie der semantischen Verwandtheit und Ähnlichkeit. Zu diesem Zweck werden die Anforderungen sowie die verfügbaren Rohdaten analysiert, ein Prototyp zur Extraktion der gewünschten Daten entwickelt und die mit dem Prototyp gewonnenen Daten in Bezug auf die zuvor formulierten Anforderungen evaluiert

MYOD-1 in normal colonic mucosa : role as a putative biomarker?

Background DNA methylation of promoter-associated CpG islands of certain genes may play a role in the development of colorectal cancer. The MYOD-1 gene which is a muscle differentiation gene has been showed to be significantly methylated in colorectal cancer which, is an age related event. However the role of this gene in the colonic mucosa is not understood and whether methylation occurs in subjects without colon cancer. In this study, we have determined the frequency of methylation of the MYOD-1 gene in normal colonic mucosa and investigated to see if this is associated with established colorectal cancer risk factors primarily ageing. Results We analysed colonic mucosal biopsies in 218 normal individuals and demonstrated that in most individuals promoter hypermethylation was not quantified for MYOD-1. However, promoter hypermethylation increased significantly with age (p < 0.001 using regression analysis) and this was gender independent. We also showed that gene promoter methylation increased positively with an increase in waist to hip (WHR) ratio – the latter is also a known risk factor for colon cancer development. Conclusions Our study suggests that promoter gene hypermethylation of the MYOD-1 gene increases significantly with age in normal individuals and thus may offer potential as a putative biomarker for colorectal cancer

Magmatic processes in developing oceanic crust revealed in a cumulate xenolith collected at the East Pacific Rise, 9°50′N

Author Posting. © American Geophysical Union, 2006. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 7 (2006): Q12O04, doi:10.1029/2006GC001316.The petrology and geochemistry of a xenolith, a fragment of a melt-bearing cumulate, within a recently erupted mid-ocean ridge (MOR) lava flow provide information on petrogenetic processes occurring within the newly forming oceanic crust beneath the northern East Pacific Rise (NEPR). The xenolith reveals important petrologic information about MOR magmatic systems concerning (1) melt distribution in a crystal-dominated mush; (2) melt-crystal reactions within the mush; (3) the chemistry of melts that have contributed to the cumulate lithology; and (4) the chemistry of axial melts that enter the axial magma system. The xenolith was enclosed within a moderately primitive, normal mid-ocean ridge basalt (NMORB) erupted in 1991 within the neovolcanic zone of the NEPR, at approximately 9°50′N. The sample is a matrix-dominated, cumulate olivine anorthosite, composed of anorthite (An94-90) and bytownite (An89-70), intergranular olivine (Fo86±0.3), minor sulfide and spinel, and intergranular glass. Marginal corrosion of plagioclase, and possibly olivine, and internal remelting of plagioclase indicate syntexis. It is surmised that the pore volume was eviscerated several times with moderately primitive basaltic melts and reduced by intergranular crystallization of forsteritic olivine. The presence of anorthite as a cumulate phase in the xenolith and the observation of anorthite xenocrysts in NMORB lavas, and as a cumulate phase in ophiolite gabbros, indicate that Ca-rich melts that are not a part of the NMORB lineage play an important role in the construction of the oceanic crust.The Mineral Resources Program, USGS, provided support to W.I.R. for this research. Field and laboratory research was supported by NSF grants OCE-9402360, 9403773, and 0138088 to M.R.P. and NSF grants OCE-9819261 and OCE-0525863 to D.J.F

Epistemic trust: modeling children's reasoning about others' knowledge and intent

A core assumption of many theories of development is that children can learn indirectly from other people. However, indirect experience (or testimony) is not constrained to provide veridical information. As a result, if children are to capitalize on this source of knowledge, they must be able to infer who is trustworthy and who is not. How might a learner make such inferences while at the same time learning about the world? What biases, if any, might children bring to this problem? We address these questions with a computational model of epistemic trust in which learners reason about the helpfulness and knowledgeability of an informant. We show that the model captures the competencies shown by young children in four areas: (1) using informants’ accuracy to infer how much to trust them; (2) using informants’ recent accuracy to overcome effects of familiarity; (3) inferring trust based on consensus among informants; and (4) using information about mal-intent to decide not to trust. The model also explains developmental changes in performance between 3 and 4 years of age as a result of changing default assumptions about the helpfulness of other people.Patrick Shafto, Baxter Eaves, Daniel J. Navarro and Amy Perfor

Identification of β-catenin binding regions in colon cancer cells using ChIP-Seq

Deregulation of the Wnt/β-catenin signaling pathway is a hallmark of colon cancer. Mutations in the adenomatous polyposis coli (APC) gene occur in the vast majority of colorectal cancers and are an initiating event in cellular transformation. Cells harboring mutant APC contain elevated levels of the β-catenin transcription coactivator in the nucleus which leads to abnormal expression of genes controlled by β-catenin/T-cell factor 4 (TCF4) complexes. Here, we use chromatin immunoprecipitation coupled with massively parallel sequencing (ChIP-Seq) to identify β-catenin binding regions in HCT116 human colon cancer cells. We localized 2168 β-catenin enriched regions using a concordance approach for integrating the output from multiple peak alignment algorithms. Motif discovery algorithms found a core TCF4 motif (T/A–T/A–C–A–A–A–G), an extended TCF4 motif (A/T/G–C/G–T/A–T/A–C–A–A–A–G) and an AP-1 motif (T–G–A–C/T–T–C–A) to be significantly represented in β-catenin enriched regions. Furthermore, 417 regions contained both TCF4 and AP-1 motifs. Genes associated with TCF4 and AP-1 motifs bound β-catenin, TCF4 and c-Jun in vivo and were activated by Wnt signaling and serum growth factors. Our work provides evidence that Wnt/β-catenin and mitogen signaling pathways intersect directly to regulate a defined set of target genes

Thrombospondin-4 is a putative tumour-suppressor gene in colorectal cancer that exhibits age-related methylation

<p>Abstract</p> <p>Background</p> <p><it>Thrombospondin-4 </it>(<it>THBS4</it>) is a member of the extracellular calcium-binding protein family and is involved in cell adhesion and migration. The aim of this study was to evaluate the potential role of deregulation of <it>THBS4 </it>expression in colorectal carcinogenesis. Of particular interest was the possible silencing of expression by methylation of the CpG island in the gene promoter.</p> <p>Methods</p> <p>Fifty-five sporadic colorectal tumours stratified for the CpG Island Methylator Phenotype (CIMP) were studied. Immunohistochemical staining of THBS4 protein was assessed in normal and tumour specimens. Relative levels of <it>THBS4 </it>transcript expression in matched tumours and normal mucosa were also determined by quantitative RT-PCR. Colony forming ability was examined in 8 cell lines made to overexpress THBS4. Aberrant promoter hypermethylation was investigated as a possible mechanism of gene disruption using MethyLight. Methylation was also assessed in the normal colonic tissue of 99 patients, with samples biopsied from four regions along the length of the colon.</p> <p>Results</p> <p><it>THBS4 </it>expression was significantly lower in tumour tissue than in matched normal tissue. Immunohistochemical examination demonstrated that THBS4 protein was generally absent from normal epithelial cells and tumours, but was occasionally expressed at low levels in the cytoplasm towards the luminal surface in vesicular structures. Forced THBS4 over-expression caused a 50-60% repression of tumour colony growth in all eight cell lines examined compared to control cell lines. Tumours exhibited significantly higher levels of methylation than matched normal mucosa, and <it>THBS4 </it>methylation correlated with the CpG island methylator phenotype. There was a trend towards decreased gene expression in tumours exhibiting high <it>THBS4 </it>methylation, but the correlation was not significant. <it>THBS4 </it>methylation was detectable in normal mucosal biopsies where it correlated with increasing patient age and negatively with the occurrence of adenomas elsewhere in the colon.</p> <p>Conclusions</p> <p><it>THBS4 </it>shows increased methylation in colorectal cancer, but this is not strongly associated with altered gene expression, either because methylation has not always reached a critical level or because other factors influence <it>THBS4 </it>expression. <it>THBS4 </it>may act as a tumour suppressor gene, demonstrated by its suppression of tumour colony formation <it>in vitro</it>. <it>THBS4 </it>methylation is detectable in normal colonic mucosa and its level may be a biomarker for the occurrence of adenomas and carcinoma.</p

Memory for expectation-violating concepts:The effects of agents and cultural familiarity

Previous research has shown that ideas which violate our expectations, such as schema-inconsistent concepts, enjoy privileged status in terms of memorability. In our study, memory for concepts that violate cultural (cultural schema-level) expectations (e.g., "illiterate teacher", "wooden bottle", or "thorny grass") versus domain-level (ontological) expectations (e.g., "speaking cat", "jumping maple", or "melting teacher") was examined. Concepts that violate cultural expectations, or counter-schematic, were remembered to a greater extent compared with concepts that violate ontological expectations and with intuitive concepts (e.g., "galloping pony", "drying orchid", or "convertible car"), in both immediate recall, and delayed recognition tests. Importantly, concepts related to agents showed a memory advantage over concepts not pertaining to agents, but this was true only for expectation-violating concepts. Our results imply that intuitive, everyday concepts are equally attractive and memorable regardless of the presence or absence of agents. However, concepts that violate our expectations (cultural-schema or domain-level) are more memorable when pertaining to agents (humans and animals) than to non-agents (plants or objects/artifacts). We conclude that due to their evolutionary salience, cultural ideas which combine expectancy violations and the involvement of an agent are especially memorable and thus have an enhanced probability of being successfully propagated. © 2014 Porubanova et al

Treatment for Mild Chronic Hypertension during Pregnancy.

BACKGROUND: The benefits and safety of the treatment of mild chronic hypertension (blood pressure, \u3c160/100 mm Hg) during pregnancy are uncertain. Data are needed on whether a strategy of targeting a blood pressure of less than 140/90 mm Hg reduces the incidence of adverse pregnancy outcomes without compromising fetal growth. METHODS: In this open-label, multicenter, randomized trial, we assigned pregnant women with mild chronic hypertension and singleton fetuses at a gestational age of less than 23 weeks to receive antihypertensive medications recommended for use in pregnancy (active-treatment group) or to receive no such treatment unless severe hypertension (systolic pressure, ≥160 mm Hg; or diastolic pressure, ≥105 mm Hg) developed (control group). The primary outcome was a composite of preeclampsia with severe features, medically indicated preterm birth at less than 35 weeks\u27 gestation, placental abruption, or fetal or neonatal death. The safety outcome was small-for-gestational-age birth weight below the 10th percentile for gestational age. Secondary outcomes included composites of serious neonatal or maternal complications, preeclampsia, and preterm birth. RESULTS: A total of 2408 women were enrolled in the trial. The incidence of a primary-outcome event was lower in the active-treatment group than in the control group (30.2% vs. 37.0%), for an adjusted risk ratio of 0.82 (95% confidence interval [CI], 0.74 to 0.92; P CONCLUSIONS: In pregnant women with mild chronic hypertension, a strategy of targeting a blood pressure of less than 140/90 mm Hg was associated with better pregnancy outcomes than a strategy of reserving treatment only for severe hypertension, with no increase in the risk of small-for-gestational-age birth weight. (Funded by the National Heart, Lung, and Blood Institute; CHAP ClinicalTrials.gov number, NCT02299414.)