Evaluation of Nigerian animal feeds by particle-induced X-ray emission

There is need to evaluate the locally available animal feeds in Nigeria so as to be able to combine them in acceptable proportions to the animals to achieve the desired growth rate. The technique of particle-induced X-ray emission (PIXE) was employed for the evaluation of these locally available animal feeds, which include Panicum maximum (Guinea grass), Cynodon plectostachyum (grass), Leucaena leucephala (legume), Calopogonium mucunoides (legume), Gliricidia sepium (legume), Euphorbia polychrome (legume), Pueraria phaseloides (legume), and Centrosema pubescens (legume). The proton beam delivered by the 2.5-MV AN 2,000 Van de Graaff accelerator at the International Centre for Theoretical Physics Laboratori Nazionali di Legnaro (LNL), Padova, Italy was used for the PIXE measurements. Twenty-one different elements were detected at various concentrations and their nutritional effects on different animals are discussed.

Coulomb energy differences in t = 1 mirror rotational bands in (50)Fe and (50)Cr

Gamma rays from the N = Z-2 nucleus (50)Fe have been observed, establishing the rotational ground state band up to the state J(pi) = 11+ at 6.994 MeV excitation energy. The experimental Coulomb energy differences, obtained by comparison with the isobaric analog states in its mirror (50)Cr, confirm the qualitative interpretation of the backbending patterns in terms of successive alignments of proton and neutron pairs. A quantitative agreement with experiment has been achieved by exact shell model calculations, incorporating the differences in radii along the yrast bands, and properly renormalizing the Coulomb matrix elements in the pf model space.

Social status in mice: behavioral, endocrine and immune changes are context dependent

The aim of the present study was to investigate the effect of social status on the endocrine, immune and behavior response of male mice. We found that in mice reared in a group of siblings since weaning, no difference exists between dominants and subordinates in basal corticosterone level, in behavior in the open-field test (OFT) and in a series of immune parameters. These results suggest that living with siblings is not a stressful condition for either dominant or subordinate mice. Therefore, group-housed siblings can be regarded as a valid control group in social stress studies. When mice were subjected to chronic psychosocial stress for 21 days, four types of social outcome occurred: residents becoming dominants, intruders becoming subordinates, residents becoming subordinates and intruders becoming dominants. Interestingly, the behavioral profile in the OFT revealed a status-dependent effect, with resident dominants (RD) and intruder dominants (InD) showing the highest locomotor and exploratory activity, whereas the corticosterone level was higher than control for all four categories. In addition, a context-dependent effect emerged at the immune level: resident subordinates (RS) had a reduced splenocyte proliferation and IL-4 and IL-10 production. Mice in all the other three social ranks showed no immune alterations. Therefore, the loss of an individual's social rank position seems a promising field of study to investigate the psychological impact of stressful events.

Methodology of motor skill and laterality: new test of hand preference in Macaca nemestrina

Ten female pig-tailed macaques (Macaca nemestrina) were tested for hand preference and hand skill (i.e., speed of performance and error rate). The experimental task was naturalistic, calling for adaptive manual skills and fine manipulation: the monkeys had to remove small food rewards embedded in a vertical array, and precision opposition of thumb and forefinger was needed to extract each pellet. Each monkey was tested 10 times on 10 different days. The results indicated individual hand preference rather than population-level handedness; however, a tendency toward right predominance was found. The results on hand skill showed a relation between error rate and hand preference, as the preferred hand made fewer errors. A different and unexpected finding was obtained when skill was evaluated in terms of speed of performance: in adult subjects the left hand was quicker than the right. Therefore, different kinds of skill showed different patterns in relation to hand preference.

Social learning in the golden hamster (Mesocricetus auratus)

This study investigates whether golden hamster (Mesocricetus auratus) pups can acquire a new behavior by interacting with an experienced adult conspecific. The behavior consisted of using teeth and forepaws to retrieve a piece of food dangling from a small chain. Instrumental learning techniques were used to train the demonstrators. Four groups of pups were exposed to different kinds of social experience. In the first group, the pups interacted with their skilled mother; in the second group, they did the same with their inexperienced mother; in the third group, they interacted with inexperienced littermates; and in the fourth group, the pups were tested individually. At the end of an acquisition period, the pups were tested individually to assess their performance. The results demonstrate that interacting with a skilled mother has a remarkable effect on the acquisition of a new feeding behavior by hamster pups.