Sinuous Trajectory Research Articles

Estudo morfológico do funículo espermático em ovinos da raça Corriedale (Ovis aries, L. 1758)

We have been studied histological aspect of 40 pairs of spermatic cord in adults Corriedale sheep. It was observed that structures were wrapped up a thin layer of dense fibroelastic connective tissue with variable thickness and folding, recovered by mesotelium, which involves all the neurovascular cord, and forms the mesoductus deferents. Under this arrangement there was a layer of loose fibroelastic tissue involving partially the cord and insulating in the deferential and abdeferential regions the vessels and nerves of the epididimus. Around the mesoductus deferents the subcapsular tissue forms with the internal layer of the meso, which protects vessels and nerves. In the abdeferential region we can see a little fatty tissue between vessels and nerves. A dense connective tissue with elastic fibers occurs between vessels and nerves of the testis and vessels of the deferential an abdeferential regions. The vascular arrangement shows in the cord the sinuous trajectory of the testicular artery recovered by the plexus pampiniformis, whose veins shows connections and have no valves. The veins of the epididimus and ductus deferents are subcapsular. The length of the intra spermatic cord segment of the testicular artery has a medium, maximum and minimal ranges, respectively 150.4 cm, 198.0 cm and 73.3 cm, on the right, and 149.6 cm, 189.2 cm and 90.0 cm, on the left. There were no statistical differences between the right and left medium ranges.

Functional types of diving beetle (Coleoptera: Hygrobiidae and Dytiscidae), as identified by comparative swimming behaviour

The swimming behaviour of ten species of diving beetles was studied with a video image analysing system, with the aim of testing the interpretation of their size and shape as functional characters reflecting adaptations to different swimming strategies. Velocity, sinuosity of the trajectory, and the relation between the two were studied in an unobstructed aquarium and, for the four largest species, in an aquarium with vertical sticks. Species predicted to be poor swimmers had the lowest average and maximum velocities. A globular species considered to have high manoeuvrability swam in highly sinuous trajectories, and could maintain this sinuosity at a wide range of velocities. One of the larger species, considered to be adapted to high speed swimming, also swam in highly sinuous trajectories, but only at slow velocities; its swimming pattern was considered to be the product of behavioural rather than morphological constraints. For two of the largest species, there was a significant decrease in sinuosity at higher velocities, whilst another was found to have a good compromise between velocity and manoeuvrability. In the aquarium with obstacles all the species reduced their maximum velocity, while the effect on sinuosity varied between species. Although the space limitation of the aquarium and the lack of motivation could have prevented some species from reaching their maximal velocities, a good agreement was found between the predicted and the actual swimming characteristics.

Functional types of diving beetle (Coleoptera: Hygrobiidae and Dytiscidae), as identified by comparative swimming behaviour

The swimming behaviour of ten species of diving beetles was studied with a video image analysing system, with the aim of testing the interpretation of their size and shape as functional characters reflecting adaptations to different swimming strategies. Velocity, sinuosity of the trajectory, and the relation between the two were studied in an unobstructed aquarium and, for the four largest species, in an aquarium with vertical sticks. Species predicted to be poor swimmers had the lowest average and maximum velocities. A globular species considered to have high manoeuvrability swam in highly sinuous trajectories, and could maintain this sinuosity at a wide range of velocities. One of the larger species, considered to be adapted to high speed swimming, also swam in highly sinuous trajectories, but only at slow velocities; its swimming pattern was considered to be the product of behavioural rather than morphological constraints. For two of the largest species, there was a significant decrease in sinuosity at higher velocities, whilst another was found to have a good compromise between velocity and manoeuvrability. In the aquarium with obstacles all the species reduced their maximum velocity, while the effect on sinuosity varied between species. Although the space limitation of the aquarium and the lack of motivation could have prevented some species from reaching their maximal velocities, a good agreement was found between the predicted and the actual swimming characteristics.