In a study of the benthic polychaete fauna of the southern Gulf of Mexico and the Caribbean Sea, several specimens of the terebellid polychaete Scionides reticulata (Ehlers) were found to host endoparasitic copepods that represent an undescribed species of the rare cyclopoid genus Entobius Dogiel, 1948. The new species, E. scionides sp. n., can be distinguished from its congeners by a combination of characters including a genital region without constrictions, three-segmented antennules, a reduced antenna with a blunt terminal process, reduced ornamentation of endopods of legs 1-4 and its relatively small size (2.3-2.7 mm). It is the smallest species of the genus. Comments on immature females are also provided, but males of this species remain unknown. It has a high prevalence (53%) in populations of the terebellid S. reticulata in the southern Gulf of Mexico, but it is absent from the Caribbean. This is the first occurrence of this copepod genus in the Americas. The finding of the new species of Entobius in S. reticulata confirms the strict specificity of most members of the genus and expands the host range of this copepod genus. A key for the identification of the species of Entobius is provided.
Comparative scanning electron microscopical studies were carried out on Chonopeltis australis Boxshall, 1976 collected from different localities in the Orange-Vaal River System in South Africa and on material of Chonopeltis minutus Fryer, 1977 and Chonopeltis australissimus Fryer, 1977 on loan from the Albany Museum, Grahamstown. This elucidates the fine structure of morphological features, which are of taxonomic importance and illustrates the significance of the copulatory structures on the legs as a taxonomic tool. It was also concluded that C. australissimus is the same as C. minutus, with C. australissimus the junior synonym.
The morphology, physiology, behaviour and ecology of spiralling whitefly, Aleurodicus dispersus Russell (Hemiptera: Aleyrodidae) on different host plants differ greatly. The genetic differences between the A. dispersus populations on 17 host plants were evaluated in the current study. Microsatellite markers were used to identify the presence of host-related genetic variation among A. dispersus populations. Our research clearly shows that there is a significant amount of genetic divergence among the A. dispersus populations on 17 host plants in India. The spiralling whitefly on acalypha and calotropis were genetically more distinct than whiteflies on other host plants. Various population genetic parameters, like heterozygosity, Nei's genetic distance, fixation indices (FST), source of genetic variation in AMOVA, etc. indicate that populations of spiralling whiteflies differ greatly genetically, probably because the spiralling whitefly populations on the Indian sub-continent came from multiple sources. The results of this study have implications for the quarantine protection strategy against this invasive pest.
Let f(t, x) be a vector valued function almost periodic in t uniformly for x, and let mod(f) = L1 ⊕ L2 be its frequency module. We say that an almost periodic solution x(t) of the system x˙ = f(t, x), t ∈ , x ∈ D ⊂ Rn is irregular with respect to L2 (or partially irregular) if (mod(x) + L1) ∩ L2 = {0}. Suppose that f(t, x) = A(t)x + X(t, x), where A(t) is an almost periodic (n × n)-matrix and mod(A) ∩ mod(X) = {0}. We consider the existence problem for almost periodic irregular with respect to mod(A) solutions of such system. This problem is reduced to a similar problem for a system of smaller dimension, and sufficient conditions for existence of such solutions are obtained.
The article describes fundamental and application results obtained in the Department of Quantum Electronics of the Institute of Radio-Engineering and Electronics (IRE) of Czechoslovak Academy of Sciences in Prague. The early success in detection of the Doppler effect of radiation reflected from the first satellite orbiting the Earth - Sputnik (1957) was in the Department followed by systematic work in the area of ammonia masers, both 14NH3 and 15NH3 (1963-72). Short information is given on the first graduate courses in quantum electronics (1963-64) organized by the Department. Department's program of laser development and applications is discussed in details. The results of four key research projects are reported in the article, i.e., (a) ruby laser and its application in ophthalmology (including the first laser surgery of retina carried out in our laboratory), (b) carbon dioxide IR lasers, (c) UV-Vis gas lasers (blue He-Cd laser, near-ultraviolet nitrogen laser), and (d) tunable dye lasers. Unfortunately, the politically motivated dissolution of the Department in early seventies ended all the promising programs., Jan Blabla, Viktor Trkal., Obsahuje bibliografii, and V anglickém názvu uvedeno chybně Quatum - správně = Quantum