The article focuses on three main questions: (1) What are the legislative and structural conditions which either promote or hinder the integration of immigrants of different origin in the spheres of labour and housing market and in the area of political participation? (2) How does the integration of different immigrant groups develop? (3) What institutions aiming at the integration of foreigners are there in Vienna and what activities, eventually measures, do they bring about? The paper characterizes the theoretical approaches to the processes of migration and provides a specification of the very term of integration. In a voluminous chapter, the historical context of the immigration to Vienna during the 1980s and 1990s is outlined. In their conclusion the authors state, that integration represents a complex and demanding process, which is determined by a system of institutional, cultural and individual factors. In Vienna, many problems still continue to exist especially in the sphere of housing (marginalization of foreigners on the housing market) and on the labour market. The threat of unemployment, that might cause a loss of the residence permit, represents a heavy burden on the migrant population. The reality of the immigrants' problems reveals, that the common practice of granting permanent residence as well as full social and political equality only after having received Austrian citizenship is no longer sufficient and does not correspond to the contemporary needs. According to the authors' opinion, a change in legislature would be advisable. But even such a change will probably not eliminate all the problems of integration in the sphere of culture, where it would be necessary to find out other means to mitigate the heavy burden of integration resting on the shoulders of the immigrants.
Intense infections of a variant of Myxobolus procerus (Kudo, 1934) are described from trout-perch (Percopsis omiscomaycus (Walbaum)) collected in Duluth Harbor, Lake Superior, USA. This particular population of parasites has spores that are identical in shape (narrow pyriform) to those described for M. procerus except that they are significantly smaller (13-14.5 pm long versus 15-17 pm long). In contrast to what was originally described for M. procerus, the plasmodia develop primarily within red and white striated muscle fibres and only rarely among the subdermal connective tissue. Most plasmodia were at or near the same stage of development. Typical development involves growth within the fibre. The parasite eventually replaces the entire content of the host cell and appears to halt development before rupturing the outer cell membrane. The only obvious host response was an occasional cyst being invaded by a localized cellular infiltrate. Infected fish appeared of normal health and no grossly evident myoliquefaction was seen. The infections involved several hundred plasmodia per fish and the question of why such unusually high levels of infection would develop in hosts inhabiting a polluted habitat is raised. It is suggested that proliferation of a pollution tolerant oligochaete (the suspected alternate host) in the harbour and/or a compromised host immune system may have increased the probability of successful transmission and development in trout-perch living in the harbour.
An interference between a thermosensitive (ts) mutant and the wild-type (wt) of tick-borne encephalitis (TBE) virus in Ixodes ricinus L, and Rhipicephalus appendicuiatus (Neumann) ticks is reported. /. ricinus females were dually infected by a parenteral inoculation of ts and wt strains at 10-day interval. Interference was demonstrated by the lowered ability of wt virus to replicate in ticks previously infected by ts virus. The wt virus was demonstrated in only 30% of the ticks; the average virus titre was lowered by 2.1 log|0 compared with the control group, which was infected with the wt virus only. The oral infection of R. appendicuiatus ticks with the same viruses also revealed an interference with the growth of the superinfecting wt virus. While in the control group all the ticks became infected, in the dually infected group the wt virus was found in only 50% of the ticks. However, when the ticks were infected orally with is virus and superinfected parenterally with the wt virus, no interference was observed. In a R. appendicuiatus-derived cell line persistently infected with the ts virus (100% of the cells), a partial inhibition of the growth of the superinfecting wt virus was observed. The ts virus retained its thermosensitive phenotype throughout the persistent infection of both the ticks and the tick cell line.
The effect of CO2 increase on gas exchange and water-use effíciency (WUE) in three temperate deciduous species (Fagus crenata, Ginkgo biloba and Alnus firma) under gradually-developing drought-stress was assessed. Seedlings were grown within transparent open-top cabinets and maintained for 4 monťhs at mean CO2 concentrations of either 350 (ambient; C350) or 700 pmol moT’ (elevated; C700) and combined with five water regimes [leaf water potential, higher than -0.3 (well- watered), -0.5 and -0.8 (moderate drought), -1.0 and lower than -1.2 MPa (serious drought-stress)]. Increase in CO2 concentration induced a 60 % average increase in net photosynthetic rate (P^) under well-watered conditions. The effect of C700 became more pronounced with drought stress established, with an 80 % average increase in at as low as -0.8 MPa; leaf conductance to water vapour transfer (gs) and transpiration rate (£), however, were significantly decreased. Consequently, WUE increased under drought, through drought stress affected potential E sooner than potential P^. The interaction of CO2 x drought stress on WUE was significant in that Pn was stimulated while E in C700 enriched plants resembled that of C350 plants under drought. Hence if a doubling of atmospheric CO2 concentration occurs by the mid 2U* century, then greater P^ in F. crenata, G. biloba and^. firma may be expected and the drought susceptibility of these species will be substantially enhanced.
The interactive effects of NO3 fertilization and salinity levels on leaf CO2 fixation, the dry matter accumulation, the proline and sugar contents in tomato shoots were determined in a greenhouse experiment using a well-controlled aerohydroponic systém. Under high salinity levels, increasing N fertilization from 5 mM NO3 up to 20 mM NO3 was ineffective in countering adverse effects of growth. Photosynthesis was inhibited as a result of both osmotic and specific ion effects. The high šalině concentrations stimulated the sugar accumulation in leaves, whereas the proline accumulation was primarily induced by increased NO3 levels.