Hannes Marais

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In this paper we present an analysis of an AltaVista Search Engine query log consisting of approximately 1 billion entries for search requests over a period of six weeks. This represents almost 285 million user sessions, each an attempt to fill a single information need. We present an analysis of individual queries, query duplication, and query sessions. We(More)
We motivate the use of desktop assistants in the context of web surfing and show how such a too1 may be used to support activities in both cooperative and personal surfing. , By cooperative surfing we mean surfing by a community of users who choose to cooperatively and asynchronously build up knowledge structures relevant to their group. Specifically, we(More)
In the mouse 'behavioral despair' test the immobility time was shortened by [D-Ala2,Met5]enkephalin at doses which did not modify locomotor activity. Similarly, the inhibitors of the enzymes degrading enkephalins, thiorphan and/or bestatin were effective. Their effect was antagonized by naloxone. We conclude that endogenous enkephalins are implicated in the(More)
The climbing behaviour, a stereotyped motor behaviour, is elicited in mice by stimulation of striatal dopamine receptor by low doses of apomorphine. The action of apomorphine is unexpectedly enhanced in animals pretreated with a single dose of this agent (5 mg/kg). This enhancement occurs as early as 2 h following the first administration and persists for(More)
The sensitivity of dopamine receptors in Mouse striatum has been evaluated both behaviourally (responsiveness to apomorphine as regarviour) and biochemically (striatal level of homovanillic acid and its decrease induced by apomorphine) After a single administration of apomorphine (0.25 mg.kg-1 or 5 mg.kg-1) or piribedil, another dopamine agonist, a state of(More)
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