Abstract Development of semantic Web has significantly influenced changes in Web based e-learning systems. Semantic e-learning environment is setting new requirements for storing learning objects. In order to enable interpretation of learning objects by applications and computers as well as interoperability of machines and applications, it is necessary to store not only the learning content but also its description (metadata). This is achieved thanks to homogenous semantic annotation in accordance with predefined metadata schemes. Important aspect is integration of the learning content into previously mentioned metadata schemes. This article presents certain facts that need to be considered in the process of generating consistent metadata that will be useful for manipulation of learning objects.

In this study we investigated the influence of low dosage X - ray irradiation on the incidence of chromosomal damage and changes in mitotic index (MI) in cultured peripheral lymphocytes of the Bosnian and Herzegovinian mountain horse following in vitro irradiation. X-ray irradiation induced a dose-dependent decrease in MI but only the dose of 0.5 Gy induced a significant decrease (p<0.05) in comparison with the control and other dose groups. The analysis of chromosomal damage revealed a clear dose-dependent increase in the incidence of chromosomal damage per metaphase. Significant differences (p<0.05) were detected by analysis of variance and the LSD test confirmed significant differences between cells that received 0.2 Gy and 0.5 Gy when compared to the control cells and cells that received 0.1 Gy. However, Scheeffes' test assigned significance only to the differences established between the cells that received 0.5 Gy and the other groups of lymphocytes. .