Synchronous collaborative information retrieval: techniques and evaluation

Synchronous Collaborative Information Retrieval refers to systems that support multiple users searching together at the same time in order to satisfy a shared information need. To date most SCIR systems have focussed on providing various awareness tools in order to enable collaborating users to coordinate the search task. However, requiring users to both search and coordinate the group activity may prove too demanding. On the other hand without effective coordination policies the group search may not be effective. In this paper we propose and evaluate novel system-mediated techniques for coordinating a group search. These techniques allow for an effective division of labour across the group whereby each group member can explore a subset of the search space.We also propose and evaluate techniques to support automated sharing of knowledge across searchers in SCIR, through novel collaborative and complementary relevance feedback techniques. In order to evaluate these techniques, we propose a framework for SCIR evaluation based on simulations. To populate these simulations we extract data from TREC interactive search logs. This work represent the first simulations of SCIR to date and the first such use of this TREC data

Opening the Woods: Towards a Quantification of Neolithic Clearance Around the Somerset Levels and Moors

Environmental reconstructions from pollen records collected within archaeological landscapes have traditionally taken a broadly narrative approach, with few attempts made at hypothesis testing or formal assessment of uncertainty. This disjuncture between the traditional interpretive approach to palynological data and the requirement for detailed, locally specific reconstructions of the landscapes in which people lived has arguably hindered closer integration of palaeoecological and archaeological datasets in recent decades. Here we implement a fundamentally different method for reconstructing past land cover from pollen records to the landscapes of and around the Somerset Levels and Moors — the Multiple Scenario Approach (MSA) — to reconstruct land cover for a series of 200-year timeslices covering the period 4200–2000 cal BC. Modelling of both archaeological and sediment chronologies enables integration of reconstructed changes in land cover with archaeological evidence of contemporary Neolithic human activity. The MSA reconstructions are presented as a series of land cover maps and as graphs of quantitative measures of woodland clearance tracked over time. Our reconstructions provide a more nuanced understanding of the scale and timing of Neolithic clearance than has previously been available from narrative based interpretations of pollen data. While the archaeological record tends to promote a view of long-term continuity in terms of the persistent building of wooden structures in the wetlands, our new interpretation of the palynological data contributes a more dynamic and varying narrative. Our case study demonstrates the potential for further integration of archaeological and palynological datasets, enabling us to get closer to the landscapes in which people lived

Callophycoic acids and callophycols from the Fijian red alga Callophycus serratus

Callophycoic acids A−H (1−8) and callophycols A and B (9 and 10) were isolated from extracts of the Fijian red alga Callophycus serratus, and identified by NMR, X-ray, and mass spectral analyses. These natural products represent four novel carbon skeletons, providing the first examples of diterpene−benzoic acids and diterpene−phenols in macroalgae. Compounds 1−10 exhibited antibacterial, antimalarial, and anticancer activity, although they are less bioactive than diterpene-benzoate macrolides previously isolated from this red alga