Problems in the determination of freshwater dinoflagellates (Dinophyceae)     

Dr. Jiří Popovský 《Aquatic Sciences - Research Across Boundaries》1983,45(2):365-372

According to the most recent findings mainly from the life cycles and multiplication of dinoflagellates it is shown that using only the external morphology is not sufficient for the determination of many species nor for the key. Dinoflagellates are characterized by many transient features between protozoa and algae and they cannot be introduced without difficulties.  相似文献   

The chemical compositions and surface structures of two roAp stars with lithium spots (HD 83368 and HD 60435)     

A. V. Shavrina  N. S. Polosukhina  J. Zverko  V. Khalak  V. V. Tsymbal  J. Žižňovský 《Astronomy Reports》2001,45(10):784-796

The spectra of two roAp stars have been analyzed as part of a project to study lithium in magnetic Ap stars. Variability of the Li I 6708 Å resonance doublet and rare-earth lines was detected, which can be explained using an oblique rotator model with the lithium spots located at the magnetic poles. Synthetic spectra obtained at different rotational phases have yielded the first data on the atmospheric chemical compositions of these spotted stars. Using refined atomic data and the most complete line lists has enabled a detailed study of the spectra near the Li I 6708 Å line and computation of the Li I line profile taking into account the spotted distribution of the lithium over the stellar surfaces. The positions of two lithium spots and lithium abundances for each of the spots have been determined.  相似文献   

Lake Issyk-kul,Kirgizia     

K. Savvaitova  T. Petr 《International Journal of Salt Lake Research》1992,1(2):21-46

The main limnological features of Lake Issyk-kul are described. The lake is a large (6,236 km²), deep (z_m, 668 m), closed lake in eastern Kirgizia. It lies at ∼1,607 m above sea level, but water-levels have been dropping since the last century. It is slightly saline (salinity, ∼6g L⁻¹), with Na⁺, Mg²⁺, Cl⁻ and SO ₄ ²⁻ the dominant ions. Nutrient levels are low and the lake is considered ultra-oligotrophic. Characeae dominate the macrophytes. About 300 and 117 taxa of, respectively, phytoplankton and zooplankton have been identified, withArctodiaptomus salinus the most numerous in the zooplankton. Chironomids dominate the benthos. Several endemic taxa of fish occur, of whichLeuciscus bergi was dominant until the 1970s. The fish fauna has been supplemented by many introduced species. Three mysids were introduced in 1965–8 and are now a significant part of the ecosystem. The present annual fish catch permitted is 320 t. The most important value of the lake is as a recreational resource. To promote and sustain this value requires careful, ongoing management. The most significant threats to the lake are local pollution, visitor pressure, and declining water-levels.  相似文献   

A study of the electromagnetic field of a magnetic vertical dipole on the model of homogeneous half-space with a spherical cavity     

Karel Faldus  Václav Petr  Oldřich Praus  Marta Tobyášová 《Studia Geophysica et Geodaetica》1963,7(4):372-395

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Tilt observation before rockburst     

Lumír Skalský 《Studia Geophysica et Geodaetica》1963,7(4):396-403

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Le développement de la géodésie et cartographie tchécoslovaque de 1945 à 1960     

Josef Ryšavý 《Studia Geophysica et Geodaetica》1960,4(3):312-312

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On the reflection of spherical waves at a plane interface with refractive index near to one II     

Vlastislav Cervený 《Studia Geophysica et Geodaetica》1960,4(1):20-41

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Measurements of gradients of gravity in mines     

Petr Velkoborský  Reviewer M. Burša 《Studia Geophysica et Geodaetica》1972,16(1):96-100

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An attempt to determine long-periodic variations in the drift of horizontal pendulums     

Petr Vaníček  Reviewer L. Skalský 《Studia Geophysica et Geodaetica》1971,15(3-4):416-420

Résumé On donne les résultats de l'analyse de la dérive des pendules horizontaux de la station Píbram-Bezové Hory au cours des années 1927–1938. Différemment aux résultats publiés déjà antérieurement[2], on a tout d'abord séparé par la méthode des moindres carrés la dérive linéaire et le terme à période de durée d'un an exactement et ce n'est que le reste qu'on a analysé par la méthode de l'analyse spectrale spéciale[4, 6]. On a trouvé dans les deux éléments une période de 222, respectivement 223 jours, non considérée jusqu'alors et ne pouvant pas être interprétée jusqu'à présent du point de vue physique. Les autres résultats sont en bon accord avec ceux reçus à l'origine. On peut conclure de la comparaison des phases des composantes annuelles des pendules horizontaux et du mouvement du pôle[5] que les deux événements sont du même origine.  相似文献   

Refracted wave in a horizontally stratified medium with constant velocity gradients     

Jaromír Janský 《Studia Geophysica et Geodaetica》1969,13(4):423-443

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