Two trials were conducted to test the hypothesis that broilers classified as good rather than poor feed converters (low vs. high feed-to-gain ratios, respectively) would show decreased activity (increased lethargy) and reduced fear of human caretakers. In both trials birds were reared to juvenile selection age when the 192 males with the "best" breast and leg conformation were placed into indiv...

PURPOSE To report a case of beta-hemolytic streptococcal endophthalmitis following crane-pecking injury. CASE REPORT A twelve-year-old boy was brought to us by his father with history of crane beak injury in his right eye. On examination, his vision was 6/24 Snellen's acuity. Anterior segment examination showed a full thickness two mm corneo-limbal tear at 1 o'clock with iris prolapse. Pupil ...

The standard approach in accounting for hierarchical differentiation in biology and the social sciences considers a hierarchy as a static distribution of individuals possessing differing amounts of some valued commodity, assumes that the hierarchy is generated by micro-level processes involving individuals, and attempts to reverse engineer the processes that produced the hierarchy. However, suf...

Newly hatched chicks will spontaneously peck at conspicuous objects in their field of view, and soon learn to distinguish between edible food particles and unpleasant tasting objects. To examine whether the selective pecking is based on the ability to memorize shapes, we analyzed pecking behavior of 1- to 2-days-old quail chicks (Coturnix japonica) by using ball- and triangle-shaped beads both ...

7 Chapter I A general introduction 13 Learning and memory 14 Classical conditioning 15 The context as a CS 16 Drug action as a US 16 Discrimination learning 17 Dopamine in learning 18 The Wickens' learning model 20 The hypothesis 22 Chapter II The glutamatergic and dopaminergic systems. The glutamatergic system Glutamate based transmission 25 Glutamate synthesis 26 Glutamate receptors 26 Glutam...