Pro výuku neoblíbené fyziky na středních školách je důležitá vhodná motivace, jejíž značný potenciál má historie astronomie. K jeho rozvinutí jsou v články shormážděny jednoduché kvantitativní astronomické úlohy, vycházející z historických postupů i původních hodnot v nich používaných. Interpretace úloh je přizpůsobena středoškolské úrovni, opírá se o matematická odvození, přičemž vždy je vyzdvihována především zjednodušená podstata sledovaného jevu. Úlohy mají poznávací charakter a mohou tak výrazně přispět k motivaci ve výuce fyziky., Vladimír Štefl., and Obsahuje seznam literatury
Gyrodactylus aff. mugili Zhukov, 1970 (Monogenoidea: Gyrodactylidae) is recorded and described from the gill lamellae of 11 of 35 greenback mullet, Chelon subviridis (Valenciennes) (minimum prevalence 31%), from the brackish waters of the Shatt Al-Arab Estuary in southern Iraq. The gyrodactylid was also found on the gill lamellae of one of eight Speigler's mullet, Valamugil speigleri (Bleeker), from the brackish waters of the Shatt Al-Basrah Canal (minimum prevalence 13%). Fifteen Klunzinger's mullet, Liza klunzingeri (Day), and 13 keeled mullet, Liza carinata (Valenciennes), collected and examined from southern Iraqi waters, were apparently uninfected. The gyrodactylids from the greenback mullet and Speigler's mullet were considered to have affinity to G. mugili Zhukov, 1970, and along with G. mugili may represent members of a species complex occurring on mullets in the Indo-Pacific Region. A single damaged gyrodactylid from the external surfaces of the abu mullet, Liza abu (Heckel), was insufficient for species identification. Previously identified species of Gyrodactylus recorded on L. abu in Iraq by various authors were considered possible misidentifications or accidental infections.
Charactenstícs of the pigment apparatus were studied in plants grown from tubers of the oř 3’’^ doně generation of two cultivars of potato (Solanum tuberosum L) transformed with Agrobacterium tumefaciens strains. The cv. Zvíkov carries pRiA4b T-DNA of A. rhizogenes and the vector plasmid pGA472 T-DNA carrying the gene for kanamycin resistance. The cv. Kamýk carries the vector plasmid pCB1339 which contains the kanamycin resistance gene and the cytokinin synthesis gene. In the field experiments, the plant dry matter, the relative water content, the chlorophyll (Chl) a and b contents, the Chl a/b ratio and the course of slow Chl fluorescence induction curves were not signifícantly different in transformed and control plants. The amoímt of the Chl-protein complexes of the reaction centres of both photosystems separated by electrophoresis was similar for both transformed and control plants. Howevér, the content of oligomeric light-harvesting complex was significantly higher in both the transformants.