User - Thesaurus Interaction in a Web-Based Database: An Evaluation of Users' Term Selection Behaviour

A major challenge faced by users during the information search and retrieval process is the selection of search terms for query formulation and expansion. Thesauri are recognised as one source of search terms which can assist users in query construction and expansion. As the number of electronic thesauri attached to information retrieval systems has grown, a range of interface facilities and features have been developed to aid users in formulating their queries. The pilot study reported here aimed to explore and evaluate how a thesaurus-enhanced search interface assisted end-users in selecting search terms. Specifically, it focused on the evaluation of users' attitudes toward both the thesaurus and its interface as tools for facilitating search term selection for query expansion. Thesaurusbased searching and browsing behaviours adopted by users while interacting with a thesaurus-enhanced search interface were also examined

Thesauri on the Web: current developments and trends

This article provides an overview of recent developments relating to the application of thesauri in information organisation and retrieval on the World Wide Web. It describes some recent thesaurus projects undertaken to facilitate resource description and discovery and access to wide-ranging information resources on the Internet. Types of thesauri available on the Web, thesauri integrated in databases and information retrieval systems, and multiple-thesaurus systems for cross-database searching are also discussed. Collective efforts and events in addressing the standardisation and novel applications of thesauri are briefly reviewed

Thesaurus-assisted search term selection and query expansion: a review of user-centred studies

This paper provides a review of the literature related to the application of domain-specific thesauri in the search and retrieval process. Focusing on studies which adopt a user-centred approach, the review presents a survey of the methodologies and results from empirical studies undertaken on the use of thesauri as sources of term selection for query formulation and expansion during the search process. It summaries the ways in which domain-specific thesauri from different disciplines have been used by various types of users and how these tools aid users in the selection of search terms. The review consists of two main sections covering, firstly studies on thesaurus-aided search term selection and secondly those dealing with query expansion using thesauri. Both sections are illustrated with case studies that have adopted a user-centred approach

Monitoring parasitic abundance in cage-based aquaculture : the effects of clustering

Most discussions of sampling protocols within the literature on monitoring aquatic parasites are based on the assumptions of simple random sampling. There has been a growing recognition within the fields of human and terrestrial veterinary epidemiology that data are often collected from individuals within clusters where such assumptions are not valid. These circumstances arise when monitoring ectoparasitic sea lice on Scottish salmon farms. In previous work the authors have demonstrated that significant intraclass correlation coefficients (ICC) values are associated with cage-level abundance of sea lice, particularly when the parasite reaches its adult stage of development. In this paper two sets of data from Scottish farms with ICC values for adult L. salmonis of 0.35 [0.08-0.72, 95%CI] and for adult C. elongatus of 0.42 [0.14-0.66, 95%CI] are used to investigate the implications of clustering. A Monte Carlo simulation approach is used to illustrate the effect of various sampling approaches. The protocols simulated reflect those typically used across a range of countries and production environments in which salmon are currently reared. By illustrating clearly from empirical data sets what is known by theoretical argument it is hoped that guidelines for sampling parasites, and disease monitoring more generally, within aquaculture will in future incorporate appropriate consideration of issues related to the clustering that is typically present in cage-based production systems

Assessing the impact of user interaction with thesaural knowledge structures: a quantitative analysis framework

Thesauri have been important information and knowledge organisation tools for more than three decades. The recent emergence and phenomenal growth of the World Wide Web has created new opportunities to introduce thesauri as information search and retrieval aids to end user communities. While the number of web-based and hypertextual thesauri continues to grow, few investigations have yet been carried out to evaluate how end-users, for whom all these efforts are ostensibly made, interact with and make use of thesauri for query building and expansion. The present paper reports a pilot study carried out to determine the extent to which a thesaurus-enhanced search interface to a web-based database aided end-users in their selection of search terms. The study also investigated the ways in which users interacted with the thesaurus structure, terms, and interface. Thesaurus-based searching and browsing behaviours adopted by users while interacting with the thesaurus-enhanced search interface were also examined

The use of prevalence as a measure of lice burden: a case study of Lepeophtheirus salmonis on Scottish Atlantic salmon, Salmo salar L., farms

This study investigates the benefits of using prevalence as a summary measure of sea lice infestation on farmed Atlantic salmon, Salmo salar L. Aspects such as sampling effort, the relationship between abundance and prevalence arising from the negative binomial distribution, and how this relationship can be used to indicate the degree of aggregation of lice on a site at a given time point are discussed. As a case study, data were drawn from over 50 commercial Atlantic salmon farms on the west coast of Scotland between 2002 and 2006. Descriptive statistics and formal analysis using a linear modelling technique identified significant variations in sea lice prevalence across year class, region and season. Supporting evidence of a functional relationship between prevalence and abundance of sea lice is provided, which is explained through the negative binomial distribution

The use of a general linear model to identify epidemiological factors affecting the abundance of chalimus stages of the sea louse (Lepeophtheirus salmonis) on Scottish salmon farms

In this communication chalimus lice numbers in the second, third and fourth quarters of the production cycle are examined in relation to a range of prevailing risk factors using an approach based on that already taken for mobile stages (Revie et al. in press). A total of 54 two-year production cycles from 29 farms on the West Coast of Scotland were analysed. Chalimus levels in the second six-month period of the first year of the production cycle were principally explained (adjusted R2 = 56% of the variation) by:the number of veterinary medicine treatments administered, the site hydrography and current speed characteristics. Sites with a high chalimus abundance attracted more treatments as did fish located in sites with low current speeds and an oscillatory hydrography. In contrast, chalimus levels in the third six-month period of the production cycle were principally explained (adjusted R2 = 65% of the variation) by: the abundance of mobile and chalimus stages in the preceding six-month period and treatment. It would appear that there are both management and environmental factors which affect the number of chalimus sea lice on fish in Scottish salmon farms and these have an impact on overall sea lice abundance

Sensitivity of salmon lice (Lepeophtheirus salmonis) in New Brunswick, Canada, to the organophosphate Salmosan® (w/w 50% azamethiphos) using bioassays

Bioassays have been used as a monitoring tool to determine changes in sensitivity of sea lice populations to various bath treatments during the Atlantic salmon production cycle. In this study we report on the results of bioassays conducted between 2009 and 2012 for L. salmonis with the objective of detecting changes in sea lice sensitivity to Salmosan® (w/w 50% azamethiphos), a delousing agent used in the Bay of Fundy region of New Brunswick, Canada. EC50 values ranged from 4.6 ppb to 402 ppb. Although sea lice stage was not a significant factor influencing observed EC50 values, there were significant differences among years, with 2009 being significantly lower than all other years, and 2011 being significantly higher than 2010 or 2012. Season was also found to be a significant predictor with EC50 values in the winter/spring being lower than those predicted in the summer/fall. While sea lice resistance to Salmosan® (w/w 50% azamethiphos) has not been reported from Eastern Canada, variable EC50 values indicate unmeasured influences on tolerance to Salmosan® (w/w 50% azamethiphos) in the populations of L. salmonis sampled from the Bay of Fundy during the 2009 to 2012 period. The possibility of more recent changes in sensitivity remains unknown due to the lack of a centralized repository of bioassay data or other measures that might reflect the emergence of resistant sea lice

Multivariate evaluation of the effectiveness of delousing treatment efficacy of azamethiphos (Salmosan®) against the salmon louse (Lepeophtheirus salmonis) in Atlantic salmon (Salmo salar) using wellboat, skirt and tarpaulin treatment modalities

Sea lice (Lepeophtheirus salmonis) are the most costly parasitic infestation in the culture of Atlantic salmon (Salmo salar) with control strategies relying heavily on the use of a limited number of chemotherapeutants and traditional univariate analytical tools to evaluate and optimize their delivery. Azamethiphos (Salmosan®) is a powerful delousing agent, which has been administered as a topical treatment using three different modalities: skirt-style enclosures, fully-enclosed tarpaulin enclosures and wellboats. In this study, we analyzed and evaluated the efficacy of azamethiphos treatments between these three modalities against PAAM (pre-adult males and females and, adult males) and adult female (AF) stages using a multivariate approach. The exploratory analysis revealed efficacy in the fully-enclosed tarpaulin modality to be 2.2 times greater compared to skirt-style and wellboat modalities; whereas efficacy against adult females in the wellboat modality was two times larger than in the other modalities. Using the multivariate analysis, treatment efficacy in the fully-enclosed tarpaulin modality was greater than the skirt-style modality, but no significant differences were observed between the wellboat and skirt modalities. These results should be interpreted with caution as differences existed in the abundances and proportions of sea lice stages before treatment that may affect the observed treatment efficacies. For an evaluation and comparison of treatment modalities, multivariate techniques offer added advantages over the more traditional univariate methods, in that simultaneous analysis of multiple sea lice stages and any dependencies or correlation between these stages can be effectively addressed. Statement of relevance: Control of sea lice infestation of Atlantic salmon

Examining the effect of intramammary infections with minor mastitis pathogens on the acquisition of new intramammary infections with major mastitis pathogens - a systematic review and meta-analysis

Major mastitis pathogens such as Staphylococcus aureus, Streptococcus agalactiae, Streptococcus uberis, Streptococcus dysgalactiae, and the coliforms are usually considered more virulent and damaging to the udder than minor mastitis pathogens such as Corynebacterium bovis and coagulase-negative staphylococci (CNS). The current literature contains several studies detailing analyses with conflicting results as to whether intramammary infection (IMI) with the minor pathogens decreases, increases, or has no effect on the risk of a quarter acquiring a new intramammary infection (NIMI) with a major pathogen. To investigate the available scientific evidence regarding the effect of IMI with minor pathogens on the acquisition of NIMI with major pathogens, a systematic review and meta-analysis were conducted. The total extant English- and French-language literature in electronic databases was searched and all publications cited by relevant papers were investigated. Results from 68 studies were extracted from 38 relevant papers. Random-effects models were used to investigate the effects of CNS and C. bovis on acquisition of new IMI with any of the major pathogens, as well as individually for the minor pathogens and Staph. aureus. Significant heterogeneity among studies exists, some of which could be accounted for by using meta-regression. Overall, observational studies showed no effect, whereas challenge studies showed strong and significant protective effects, specifically when major pathogens were introduced into the mammary gland via methods bypassing the teat end. Underlying risk can account for several unmeasured factors, and studies with higher underlying risk found more protective effects of minor pathogens. Larger doses of challenge organisms reduced the protective effect of minor pathogens, and studies with more stringent diagnostic criteria for pathogen IMI identified less protection. Smaller studies (those utilizing fewer than 40 cows) also showed a greater protective effect than larger studies