Evidence for behavioural thermoregulation by the world's largest fish

Many fishes make frequent ascents to surface waters and often show prolonged surface swimming following descents to deep water. This affinity for the surface is thought to be related to the recovery of body heat lost at depth. We tested this hypothesis using data from time–depth recorders deployed on four whale sharks (Rhincodon typus). We summarized vertical movements into bouts of dives and classified these into three main types, using cluster analysis. In addition to day and night ‘bounce’ dives where sharks rapidly descended and ascended, we found a third type: single deep (mean: 340 m), long (mean: 169 min) dives, occurring in daytime with extremely long post-dive surface durations (mean: 146 min). Only sharks that were not constrained by shallow bathymetry performed these dives. We found a negative relationship between the mean surface duration of dives in the bout and the mean minimum temperature of dives in the bout that is consistent with the hypothesis that thermoregulation was a major factor driving use of the surface. The relationship broke down when sharks were diving in mean minimum temperatures around 25°C, suggesting that warmer waters did not incur a large metabolic cost for diving and that other factors may also influence surface use.     

Local closed world reasoning:a personal view on current status and trends

1 Introduction In computer science and artificial intelligence,an ontology is a model of (some aspect of) the world that introduces the vocabulary of a particular domain,and specifies the meaning (semantics) of terms.     

A multi-objective model for seasonal personnel reassignment

The focus of this research was the development of a model to address the problem of reassigning summer construction workers to winter snow and ice removal teams in an efficient and cost-effective manner. The model is a multi-objective integer program that can generate the complete and precise trade-off curve between the objectives of minimizing total distance that the reassigned workforce must travel from their respective homes to one of many site locations, and minimizing the maximum distance that any one worker must travel. System constraints include demand requirements for workers at each site and the limited availability of state-owned vehicles that may be issued to workers assigned to remote sites. Details of the model structure and solution procedure are presented together with the results of an actual application.