The aim of this study was to assess the anisakid nematode distribution pattern in the fish collected from the South Shetland Islands . A total of 32 fish species were examined for the presence of nematodes in 1978, 1979, 1981 and 2007/2008. The fish were caught off the South Shetland Islands ( Elephant Island , Shishkov Island and in Admiralty Bay – King George Island ). Three genera of L3 larval nematodes were identified: Anisakis sp., Contracaecum spp. and Pseudoterranova decipiens. The infection level was higher on the shelf around the islands than in Admiralty Bay . This is explained by a higher abundance of the final hosts in the region. A comparison of the infection data from 1978/79 and 2007/2008 with data from 1994/96 (Palm et al. 1998, 2007) was done. The parameters of infection of Notothenia coriiceps and Lepidonotothen nudifrons by Pseudoterranova decipiens were decreasing within the 30 years period.
The paper deals with linear circuits synthesis with periodic parameters. It was proved that the time-varying voltages and currents of inner branches of such circuits can be calculated using linear recursive equations with periodic coefficients if signals on port are given. The stability theorem of periodic solution was formulated. Hereby described the synthesis problems appear when compensation of power supply systems is considered.