972 research outputs found
Hybrid XML Retrieval: Combining Information Retrieval and a Native XML Database
This paper investigates the impact of three approaches to XML retrieval:
using Zettair, a full-text information retrieval system; using eXist, a native
XML database; and using a hybrid system that takes full article answers from
Zettair and uses eXist to extract elements from those articles. For the
content-only topics, we undertake a preliminary analysis of the INEX 2003
relevance assessments in order to identify the types of highly relevant
document components. Further analysis identifies two complementary sub-cases of
relevance assessments ("General" and "Specific") and two categories of topics
("Broad" and "Narrow"). We develop a novel retrieval module that for a
content-only topic utilises the information from the resulting answer list of a
native XML database and dynamically determines the preferable units of
retrieval, which we call "Coherent Retrieval Elements". The results of our
experiments show that -- when each of the three systems is evaluated against
different retrieval scenarios (such as different cases of relevance
assessments, different topic categories and different choices of evaluation
metrics) -- the XML retrieval systems exhibit varying behaviour and the best
performance can be reached for different values of the retrieval parameters. In
the case of INEX 2003 relevance assessments for the content-only topics, our
newly developed hybrid XML retrieval system is substantially more effective
than either Zettair or eXist, and yields a robust and a very effective XML
retrieval.Comment: Postprint version. The editor version can be accessed through the DO
Using Proximity and Tag Weights for Focused Retrieval in Structured Documents
International audienceFocused information retrieval is concerned with the retrieval of small units of information. In this context, the structure of the documents as well as the proximity among query terms have been found useful for improving retrieval effectiveness. In this article, we propose an approach combining the proximity of the terms and the tags which mark these terms. Our approach is based on a Fetch and Browse method where the fetch step is performed with BM25 and the browse step with a structure enhanced proximity model. In this way, the ranking of a document depends not only upon the existence of the query terms within the document but also upon the tags which mark these terms. Thus, the document tends to be highly relevant when query terms are close together and are emphasized by tags. The evaluation of this model on a large XML structured collection provided by the INEX 2010 XML IR evaluation campaign shows that the use of term proximity and structure improves the retrieval effectiveness of BM25 in the context of focused information retrieval
PTEN Regulation of Local and Long-Range Connections in Mouse Auditory Cortex
Autism spectrum disorders (ASDs) are highly heritable developmental disorders caused by a heterogeneous collection of genetic lesions. Here we use a mouse model to study the effect on cortical connectivity of disrupting the ASD candidate gene PTEN (phosphatase and tensin homolog deleted on chromosome 10). Through Cre-mediated recombination, we conditionally knocked out PTEN expression in a subset of auditory cortical neurons. Analysis of long-range connectivity using channelrhodopsin-2 revealed that the strength of synaptic inputs from both the contralateral auditory cortex and from the thalamus onto PTEN-cko neurons was enhanced compared with nearby neurons with normal PTEN expression. Laser-scanning photostimulation showed that local inputs onto PTEN-cko neurons in the auditory cortex were similarly enhanced. The hyperconnectivity caused by PTEN-cko could be blocked by rapamycin, a specific inhibitor of the PTEN downstream molecule mammalian target of rapamycin complex 1. Together, our results suggest that local and long-range hyperconnectivity may constitute a physiological basis for the effects of mutations in PTEN and possibly other ASD candidate genes
Focal dermal hypoplasia (Goltz-Gorlin) syndrome with taurodontism
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74895/1/j.1754-4505.1996.tb01539.x.pd
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