Improving Retrieval Results with discipline-specific Query Expansion

Choosing the right terms to describe an information need is becoming more difficult as the amount of available information increases. Search-Term-Recommendation (STR) systems can help to overcome these problems. This paper evaluates the benefits that may be gained from the use of STRs in Query Expansion (QE). We create 17 STRs, 16 based on specific disciplines and one giving general recommendations, and compare the retrieval performance of these STRs. The main findings are: (1) QE with specific STRs leads to significantly better results than QE with a general STR, (2) QE with specific STRs selected by a heuristic mechanism of topic classification leads to better results than the general STR, however (3) selecting the best matching specific STR in an automatic way is a major challenge of this process.Comment: 6 pages; to be published in Proceedings of Theory and Practice of Digital Libraries 2012 (TPDL 2012

Molecular ecology and biogeography of methanotrophic bacteria in wetland rice fields

Methanotrophic bacteria perform a central function in our climate system representing the only biogenic sink for the greenhouse gas methane. In wetland rice fields, they function as bio-filters preventing methane produced in anoxic layers escaping into the atmosphere, attenuating the potential methane emission by up to 90%. Despite intensive studies in the past, molecular approaches have barely started to explore the full diversity of methanotrophs. Furthermore, only little is known on their ecological niche differentiation and the factors influencing their community structure. This thesis focuses on the aerobic methanotrophic communities in the wetland rice ecosystem using the pmoA gene as a functional and phylogenetic marker to detect these bacteria in the environment. A high diversity could be recorded dominated by Methylocystis and Methylosinus species (type II) and yet uncultivated bacteria grouping within type Ib methanotrophs. The rice paddy cluster 1 (RPC-1) forms the largest cluster consisting entirely of sequences obtained from paddy fields located around the world. It is only distantly related to cultivated species and might form a new genus of methanotrophs specifically adapted to wetland rice fields. Methanotrophic communities showed no large scale horizontal distribution patterns within an Italian paddy field; thus, a reduced sampling effort is sufficient to extrapolate to the field scale. However, different methanotrophic communities were detected on the rice roots compared to the field soil and the communities in different fields differed significantly. The rice roots were characterized by a high abundance of type I methanotrophs and different rice cultivars were shown to have an effect on these communities. This effect could be correlated to the plant genotype and enables to select specific cultivars for in-depth studies. Re-evaluating the pmoA gene as a phylogenetic marker for methanotrophs revealed a good correlation of the pmoA to the 16S rRNA phylogeny. Nevertheless, some exceptions suggests that methanotrophy might be evolutionary more complicated having been even exchanged between species. Furthermore, a meta-analysis of pmoA sequences from various environments revealed distinct correlations of genotypes and habitats

Studien zur Mehrsprachigkeit: Beiträge der Dortmunder Arbeitsgruppe

An der TU Dortmund, Fachgebiet Sprache und Kommunikation, wurden in den letzten zwei Jahren eine Reihe von empirischen Studien zum Thema Mehrsprachigkeit in Kindheit und Jugend durchgeführt. Mit dem vorliegenden Beitrag geben wir einen Überblick über die wichtigsten Fragestellungen und Ergebnisse, die (auch) für die sprachtherapeutische Praxis relevant sind. Dabei werden zum einen Aspekte des Phänomens diskutiert und zum anderen konkrete Vorschläge zu Anamnese, Diagnostik und Intervention gemacht.Over the last two years researchers of the TU Dortmund University, Department of Language and Communication, have been conducting a number of empirical studies on bilingualism in childhood and adolescence. Special emphasis was placed on bilingualism in the context of speech and language pathology. The overview presented summarizes main research questions and results regarding aspects of the phenomena, trait differences, anamnesis, diagnosis, and intervention

Elterliche Schulzufriedenheit in integrativer und segregativer Beschulung sprachauffälliger Kinder: Ein Vergleich zwischen Förderschule und Gemeinsamem Unterricht

Seit dem Inkrafttreten der UN-Konvention über die Rechte behinderter Menschen wird zunehmend öffentlich über die Strukturen der sonderpädagogischen Förderung in Deutschland diskutiert. Anhand einer Befragungsstudie mit 542 Eltern sprachauffälliger GrundschülerInnen, bei der die Schulzufriedenheit im Gemeinsamen Unterricht und in der Förderschule vergleichend untersucht wird, soll ein empirischer Beitrag zu dieser Debatte geliefert werden. Die Befunde zeigen, dass die Zufriedenheit der Eltern in beiden schulischen Settings gleichermaßen sehr hoch ist. Weitere Analysen machen allerdings deutlich, dass die Stigmatisierung der Kinder im integrativen Setting geringer ausfällt als bei segregativer Beschulung. Darüber hinaus sind Eltern von integrativ beschulten Mädchen und Jungen zuversichtlicher, dass ihr Kind die Sprachprobleme überwinden wird, und optimistischer in Bezug auf dessen Bildungs- und Teilhabechancen. Weiterhin wurde festgestellt, dass einige Elterngruppen deutlich geringere Chancen haben, ihren Wunsch auf integrative Unterrichtung ihres Kindes durchzusetzen.Special need education in Germany is a highly controversial topic as many favor segregated schools despite the recent UN convention on the rights of persons with disabilities. A survey was conducted with 542 parents having a child with language impairment that is either enrolled in a special need school or in an integrative elementary school setting. Results indicate equally high parental satisfaction in both systems. Further analyses, however, demonstrate higher perceived stigmatization of children in the segregated compared to the integrative setting; more optimistic view in parents who are enrolled in integrative schools regarding language improvement, career options, and social participation. Further results reveal unexpected discrimination of some families in respecting their individual choices for a school setting they believe in. Results are discussed with respect to the importance of parental choice and the need for further empirical investigation on pedagogic strategies that really work for language impaired children