Utilizing scale-free networks to support the search for scientific publications

When searching for scientific publications, users today often rely on search engines such as Yahoo.com. Whereas searching for publications whose titles are known is considered to be an easy task, users who are looking for important publications in research fields they are unfamiliar with face greater diffiulties since few or no indications of a publication’s importance to the respective fields are given. In this paper we investigate the application of the theory of scale-free networks to derive importance indicators for a collection of publications. A tool was developed to support the user in his publication search by visualizing the publications’ importance indicators derived from the number of citations received and the publication’s age as well as visualizing part of the citation network structure. A preliminary user study indicates the utility of our approach and warrants further research in that direction

Enhancing Access To Classic Children’s Literature

Project Gutenberg is a digital library that contains mostly public domain books, including a large number of works that belong to children’s literature. Many of these classic books are offered in a text-only format, which does not make them appealing for children to read. Moreover, stories that were written for children one hundred or more years ago, might not be readily understandable by children today due to diverging vocabularies and experiences. In this poster, we describe ongoing work to enhance the access to this children’s literature repository. Firstly, we attempt to automatically illustrate the children’s literature. Secondly, we link the text to background information to increase understanding and ease of reading. The overall motivation of this work is to make such publicly available books more easily accessible to children by making them more entertaining and engaging

Learning by example : training users with high-quality query suggestions

The queries submitted by users to search engines often poorly describe their information needs and represent a potential bottleneck in the system. In this paper we investigate to what extent it is possible to aid users in learning how to formulate better queries by providing examples of high-quality queries interactively during a number of search sessions. By means of several controlled user studies we collect quantitative and qualitative evidence that shows: (1) study participants are able to identify and abstract qualities of queries that make them highly effective, (2) after seeing high-quality example queries participants are able to themselves create queries that are highly effective, and, (3) those queries look similar to expert queries as defined in the literature. We conclude by discussing what the findings mean in the context of the design of interactive search systems

Hydrothermal activity and magma genesis along a propagating back-arc basin: Valu Fa Ridge (southern Lau Basin)

Valu Fa Ridge is an intraoceanic back-arc spreading center located at the southern prolongation of the Lau basin. Bathymetric observations as well as detailed sampling have been carried out along the spreading axis in order to trace hydrothermal and volcanic activity and to study magma generation processes. The survey shows that widespread lava flows from recent volcanic eruptions covered most of the Vai Lili hydrothermal vent field; only diffuse low-temperature discharge and the formation of thin layers of siliceous precipitates have been observed. Evidence of present-day hydrothermal activity at the Hine Hina site is indicated by a thermal anomaly in the overlying water column. Our studies did not reveal any signs of hydrothermal activity either above the seismically imaged magma chamber at 22°25′S or across the southern rift fault zone (22°51′S). Lavas recovered along the Valu Fa Ridge range from basaltic andesites to rhyolites with SiO2 contents higher than reported from any other intraoceanic back-arc basin. On the basis of the highly variable degrees of crystal fractionation along axis, the development of small disconnected magma bodies is suggested. In addition, the geochemical character of the volcanic rocks shows that the transition zone from oceanic spreading to propagating rifting is located south of the Hine Hina vent field in the vicinity of 22°35′S

Along- and Across-Arc Variations in the Southern Volcanic Zone, Chile

Within Collaborative Research Center (SFB574), we are studying the changes in the chemistry of olivinebearing volcanic rocks along the volcanic front of the Southern Volcanic Zone (SVZ) in Chile and in the rear and backarc in Argentina. Samples from the volcanic front (VF) have typical trace element signatures of subduction zone volcanic rocks, characterized, for example, by negative Nb and Ta anomalies and positive Pb, Sr, Cs, Rb, Ba, Th and U anomalies on incompatible element (spider) diagrams. Samples from Longavi in the forearc are distinct in having lower abundances of the HREE's, high Sr/Y and geochemical signatures characteristic of adakitic rocks believed to be derived through melting of the subducting slab. The northern Southern Volcanic Zone (NSVZ) samples from Tupungatito and San José have the most enriched highly to moderately incompatible element ratios, high Rb/Ba and low La/Ta and Ba/La, suggesting involvement of lower crust in the petrogenesis of these rocks. We observe systematic variations in Sr and Nd isotopic compositions along the arc, with Sr isotopes showing a dramatic increase and Nd isotopes showing a dramatic decrease in the NSVZ, which is where the crust begins to thicken significantly. The increase in Sr and decrease in Nd in the VF is coupled with an increase in the degree of differentiation of the Tupungatito and San José (SiO2 > 58%, MgO = 2-4%) volcanoes. On the Pb isotope diagrams, the VF rocks trend from MORB-like compositions to the field for pelagic sediments, consistent with involvement of subducted sediments in generating the VF rocks. Interestingly, samples from the NSVZ form the lower end of the VF array (have the least radiogenic Pb isotopic compositions) on the uranogenic Pb isotope diagram, but extend to the left of the rest of the VF array on the thorogenic Pb isotope diagram, showing evidence of at least a second enriched component. The presence of the second enriched component could reflect assimilation of lower crust or addition of lower crust through subduction erosion into the manlte wedge. Quaternary backarc samples in Argentina also show subduction signatures in their incompatible elements but generally show lower fluid signatures than the VF samples. Although the Pb isotopic compositions of backarc rocks are similar to MORB, the low Nd isotopic compositions indicate the presence of enriched material within the backarc. Although no systematic variation is seen in Sr and Nd isotopic composition from north to souths, the Pb isotope ratios show systematic spatial variations with the northern samples having the most enriched Pb isotope ratios. The lower fluid signatures in the backarc volcanoes, coupled with less radiogenic Pb isotopic compositions are consistent with a decreasing influence of the subduction signature into the backarc. With the addition of Hf and O isotope data we should be able to better constrain the different reservoirs involved in generating the diverse geochemical compositions of the SVZ volcanic rocks