Approximately 100 strains derived from natural populations of Drosophila melanogaster were tested for the presence or absence of P-element sequences by using two molecular probes derived from internal regions of a full-sized P element. Strains that had been collected from several continents at varying times during the past 60 years were examined. The oldest available strains, representing most ...

national identity is a main factor of stability of social and political systems. therefore one of the aims and scopes of poiltical socialization in all political systems is strengthening and reproduction of national identity. but this problem is required to exact recognition and evaluation, it is necessary to identify, dimensions, elements and indicators of national identity in order to dot sci...

Different types of sediment trap have been introduced so far to be used in erosion measuring stations, each with its own advantages and disadvantages in trapping aeolian particles. These traps have different collection and retention efficiency due to aerodynamic conditions. Some characteristics such as isokinetic feature of the trap, collection efficiency, time needed to download sediment, capa...