During a study on parasites of fish from cenotes (= sinkholes) in the Yucatan Peninsula, the following cestodes and acanthocephalans were found in 581 freshwater fish of 15 species: the cestodes Bothriocephalus acheilognathi Yamaguti, 1934, Bothriocephalus sp. (Bothriocephalidae), Nomimascolex sp. (Monticellidae), Proteocephalidea gen. sp. larv., Dendrouterina pa-pillifera (Fuhrmann, 1908) larv. and D. pilherodiae Mahon, 1956 larv. (Dilepididae), and the acanthocephalans Octospinifer-oides chandleri Bullock, 1957, Neoechinorhynchus golvani Salgado-Maldonado, 1978 (Neoechinorhynchidae), Polymorphus (syn. Arhythmorhynchus) brevis (Van Cleave, 1916) larv. (Polymorphidae), and an echinorhynchid larva. With the exception of B. acheilognathi, all tapeworms are found in Mexico for the first time; second-stage larvae of D. papillifera and D. pilherodiae from fish are reported for the first time.
The history of lasers at the Institute of Scientific Instruments of the ASCR in Brno (ISI) has begun 1249 days after the worldwide premiere of laser. The first to be put into operation at ISI was the He-Ne laser (16 October 1963). Highest attention was then paid to its further development making possible a large number of its applications. The He-Ne laser was followed by a ruby laser (4 March 1964), He-Cd laser (1970), and Nd:YAG laser (1973). The article presents all achievements concerning lasers at ISI accompanied by historic photos, their applications and routes to production at national companies. Nowadays many of these instruments and techniques are in use and are further being perfected, such as interferometric distance measurements with sub-nanometer resolution, methods of comparison of metrological etalons by femtosecond lasers, utilization of laser light for manipulations with micro-object combined with laser micro-spectroscopy., P. Zemánek, J. Lazar, O. Číp, L. Oprchalová, J. Kršek, D. Vavrouch., and Obsahuje bibliografii
This work deals with the CFD analysis of flow in the middle stage of the radial-flow multistage pump operating in turbine regime. The pump specific speed nq is equal to 23. Two complete stages are analysed with fully unsteady simulation to avoid the influence of boundary conditions and the position of rotor and stator parts on the results. The ANSYS CFX commercial CFD package is used to solve the three-dimensional Reynolds-averaged Navier-Stokes equations using Menter's SST turbulence model. and Obsahuje seznam literatury
CFD simulation is aimed on the two-stage pump operation modeling in the pump and turbine regime. The flow analysis will be focused on the proper angle of wicket gates attack and on the separation localization. This investigation should bring the geometry modifications that will increase the hydraulic efficiency. The computational model was created in preprocessor GAMBIT and software Fluent will be used for the finite computation.
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.
A comparison has been made between the chaetotaxy of the gyrodactylid monogeneans Macrogyrodactylus clarii Gussev, 1961 and M. congolensis (Prudhoe, 1957) Yamaguti, 1963 from the gills and skin, respectively, of the catfish Clarias gariepinus (Burchell) from the river Nile in Egypt. Bilaterally arranged argentophilic structures on the surface of these parasites are presumed to be sensilla and are more abundant in M. clarii than in M. congolensis especially on the ventral surface (124 vs. 66). In both species these sensilla are concentrated on the head lobes and in the pharyngeal region, but there are features of the sensilla patterns that can be used to distinguish the two species. Comparison is made with sensilla patterns of other gyrodactylids. A system of cells and dendritic processes, most probably part of the nervous system, also has an affinity for silver in the two species. There are no previous records of extensive argentophilic elements in the nervous systems of monogeneans.