Gyrodactylus salaris Malmberg, 1957 is a major pathogen of wild Salmo salar L. parr populations in Norway, and its delimitation from non-pathogenic species is important. The present study was undertaken to test the power of chaetotaxy to differentiate between three populations belonging to both the same and different clades (as stated by mtDNA) of G. salaris, in addition to three different species of gyrodactylids (G. salaris, G. thymalli and G. caledoniensis). The gyrodactylids were processed for chaetotaxy in situ and a maximum of 50 specimens per collection site were used to construct a generalised map over the sensilla. The sensilla were found in all populations to be symmetrically distributed around the median longitudinal axis, according to a formula of 7 dorsal (34 sensilla) and 8 ventral (44 sensilla) clusters on each side of the median line. The three Norwegian populations of G. salaris were found identical, as were the population of G. thymalli. The specimens of G. caledoniensis from Scotland, however, were found to differ from the Norwegian species G. salaris and G. thymalli by the position of one sensillum in two of the clusters. A comparison of the sensillum pattern of laboratory maintained G. salaris (River Lierelva) with results obtained ten years earlier, questions the temporal stability of the chaetotaxy pattern. The present results indicate that chaetotaxy can be used to discriminate between certain Gyrodactylus spp. but not generally.
a1_The photosynthetic and chlorophyll fluorescence parameters were studied in Ziziphus jujuba var. spinosus under different soil water gradients obtained by irrigation and natural water consumption. We used the rectangular hyperbola model, the nonrectangular hyperbola model, the exponential model, and the modified rectangular hyperbola model to fit our data and evaluate them quantitatively. Based on the relationship among the parameters, the effects of the availability of soil water on photosynthesis were elucidated. The results showed that: (1) The relationship between water content and photosynthetic parameters were fitted best by the modified rectangular hyperbola model, followed by the nonrectangular hyperbola model, the exponential model, and the rectangular hyperbola model. The modified rectangular hyperbola model fitted best the maximum net photosynthetic rate (PNmax) and the light-saturation point (LSP), while the nonrectangular hyperbola model fitted best the dark respiration rate (RD), the apparent quantum yield (AQY), and the light-compensation point (LCP)., a2_(2) The main reason for the net photosynthetic rate (PN) decline was that it reached a stomatal limit when the soil relative water content (RWC) was greater than 25% and it reached a nonstomatal limit when the RWC was lesser than 25%. Under these conditions, the photosynthetic apparatus of Z. jujuba was irreversibly damaged. (3) Pmax, RD, AQY, and LSP increased first and then decreased, while LCP increased contrary to the RWC. The P N light-response parameters reached optimum when the RWC was 56-73%. (4) The quantum yield of PSII photochemistry reached a maximum when RWC was 80%. Nonphotochemical quenching decreased rapidly, and the minimum fluorescence in the dark-adapted state increased rapidly when RWC was lesser than 25%. Under these conditions, PSII was irreversibly damaged. (5) The RWC range of 11-25% resulted in low productivity and low water use efficiency (WUE). The RWC range of 25-56% resulted in moderate productivity and moderate WUE, and the RWC range of 56-80% resulted in high productivity and high WUE. The RWC range of 80-95% resulted in moderate productivity and low WUE. In summary, photosynthesis of Z. jujuba was physiologically adaptable in response to water stress in sand formed from seashells. The photosynthetic and physiological activity was maintained relatively high when the RWC was between 56 and 80%; Z. jujuba seedlings grew well under these conditions., J. B. Xia, G. C. Zhang, R. R. Wang, S. Y. Zhang., and Obsahuje bibliografii
Vesmír již dávno není pro fyziky jen doménou gravitační interakce. Elektromagnetické jevy ovlivňují chování vesmírných objektů neméně výrazně jako gravitace [1, 4] a hrají klíčovou roli při vzniku hvězd, sluneční a hvězdné aktivitě, v akrečních discích nebo při vytváření výtrysků. Magnetická pole tvoří obří pavoučí síť prolínající se vesmírem, na jejíž vlákna se napojují magnetické silokřivky z nejrůznějších zdrojů. Každý zdroj magnetického pole má uzavřené silokřivky, které se do zdroje vracejí, a otevřené silokřivky, které se napojují na silokřivky z jiných zdrojů. Nejinak je tomu například u střelky kompasu. Silokřivky v oblasti pólů se do magnetky již nevracejí a napojují se na magnetické silokřivky zemského pole. Právě proto míří magnetka severojižním směrem., Petr Kulhánek., and Obsahuje seznam literatury
The aim of this contribution is to describe the removal efficiency of individual fractions of natural organic matter (NOM) during water treatment. Two types of surface water with an increased concentration of NOM of various origins were analysed. It was shown that the NOM removal efficiency depends on the NOM character and reaction conditions. The optimised doses of destabilisation reagents influence especially the removal of hydrophilic charged (CHA) and very hydrophobic acids (VHA) fractions during treatment of both types of raw water (φCHA = 0.78-0.86, φVHA = 0.51-0.88). In contrast, removal of hydrophilic neutral (NEU) fraction was very low (φNEU = 0.13-0.22). and Příspěvek se zabývá odstranitelností jednotlivých frakcí přírodních organických látek (NOM) při úpravě povrchových vod se zvýšeným obsahem NOM různého typu. Výsledky ukazují, že účinnost odstranění NOM závisí na charakteru NOM a na reakčních podmínkách. Při optimalizovaných dávkách destabilizačního činidla byla, při úpravě obou typů vod, nejlépe odstraněna frakce VHA (silně hydrofobní kyseliny) a frakce hydrofilní nabitá (CHA) (φCHA = 0.78-0.86, φVHA = 0.51-0.88). Naopak odstranění hydrofilní nenabité frakce (NEU) bylo minimální (φ = 0.13-0.22).