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We investigated the spatial and temporal distribution of foraging effort by lactating Antarctic fur seals Arctocephalus gazella at Heard Island using satellite telemetry and time-depth recorders. Two principal diving types were identified: 'deep' dives averaging 48.6 m, and 'shallow' dives averaging 8.6 m. Discriminant function analyses were used to assign dives based on their depth and duration. Generalised linear mixed-effects models of night dives (> 80% of all dives) indicated both spatial and temporal effects on the distribution of deep and shallow dives. Deep dives were more common in the deeper shelf waters of the Kerguelen Plateau, and these dives predominantly occurred after sunset and before sunrise. In contrast, shallow dives were more common in slope waters on the southeastern margin of the Kerguelen Plateau in the hours either side of local midnight. We suggest that these 2 distinct diving types reflect the targeting of channichthyid (deep dives) and myctophid (shallow dives) fish, and are indicative of spatial and temporal differences in the availability of these 2 important prey groups. We also identified 3 distinct behavioural dive groups (based on multidimensional scaling of 19 diving and foraging trip parameters) that also differed in their spatial distribution and in their relative importance of deep and shallow dives. The present study provides some of the first evidence that diving strategies are not only influenced by where foraging takes pace, but also when.

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The use of spark-ignited (SI) production-style vehicle engines in high-performance applications is a growing trend in the aftermarket performance industry. However, the use of economically designed components, specifically cylinder heads, presents challenges when used in this manner. The study of flow through a cylinder head is a topic of extensive research where complex flow patterns have made modelling and computer simulation challenging. A variety of approaches have been employed including simplifying model assumptions, different boundary conditions, different meshing strategies, and different turbulence models. The focus of this research is modification of the air intake port geometry of a VR38DETT engine in order to increase the volumetric flow rate past a current limit of 330.4 CFM at 0.700” valve lift, which has been achieved by porting methods alone. Using SolidWorks, a computational fluid dynamics model was developed, verified, validated, and analyzed. The modelling methodology was verified using a mesh convergence study of the pressure drop along a pipe with a bend. Also, the bend loss coefficient was compared to published values for different ratios of the centerline radius of the bend to the internal pipe diameter. The model was then validated using steady-state flow bench test data. Results of the analysis indicate that the cylinder head can achieve a flow rate 5.15% above the current limit when the port geometry is enlarged and the short-side radius is increased, only in support of a cooling passage geometry change.