Showing papers by "Kyungpook National University published in 1975"

Unconformity-bounded stratigraphic units

Abstract: Unconformities have been used commonly as boundaries of stratigraphic units; such unconformity-bounded units have played an important role in the development of stratigraphy and will continue to do so. However, their value has been impaired by failure to understand that they constitute an independent category of stratigraphic units — that of unconformity-bounded units — with a distinctive significance of its own, and that they should not be confused with other commonly accepted kinds of stratigraphic units. Many unconformity-bounded units have been regarded as lithostratigraphic units, even though they may be characterized by being bounded by unconformities. In order to maintain the original concept of lithostratigraphic units, this usage should be avoided. Similarly, many unconformity-bounded units are considered to be chronostratigraphic units in spite of the fact that unconformity surfaces inevitably cut across isochronous horizons and hence cannot be true chronostratigraphic boundaries. If unconformity-bounded units are to be the basis for chronostratigraphic units, their boundaries should be redefined elsewhere in continuously deposited sections. Otherwise, they should be regarded not as chronostratigraphic units but as belonging to the here-proposed independent category of unconformity-bounded units . Probably the most widely used unconformity-bounded units are those bounded by unconformities of regional or interregional magnitude and comparable in thickness to supergroups and in time span to one or more stratigraphic systems. The formal term “synthem” is recommended for these units when they are of major rank. Synthems are useful in cratonic areas where stratigraphic schemes consisting of units of this kind provide a basis for tectonic correlation and best reveal geologic (particularly tectonic) history. The use of synthems also promotes the recognition of natural geologic provinces and aids in the establishment of natural stratigraphic classifications. The term “interthem” is proposed for minor disconformity-bounded units comparable in thickness with a formation or in time span with a stage. The prefixes “sub” and “super” may be used if further ranks of classification are needed.

Clonorchis sinensis in Kyungpook Province, Korea: 1. Distribution and demonstration of the cercaria of Clonorchis sinensis from snail, Parafossarulus manchouricus Bourgigant.

Abstract: Studies were conducted in rivers in Kyungpook Province, Korea from July 1970 to September 1974 to determine the stations where Parafossarulus manchouricus, the intermediate snail host of Clonorchis sinensis, are abundant, and the infection rates of these snails with the cercaria of Clonorchis sinensis. Snail collections were made during four consecutive summers(July to September in each year). Ten snail habitats were found. The population density of the snails per square meter of the river bottom ranged from 25 to 250. The highest population of snails was encountered at the Dong-chon station. Cercaria studies by means of the immersing and crushing technics indicated surprisingly low rate of Clonorchis sinensis infection among the snails examined. The proportion of infected snails in Kyungpook Province was 0.8 per thousand of all snails examined. Results indicated that the Parafossarulus manchouricus exists in limited areas within the rivers under study and the infection of the snail with the cercaria of Clonorchis sinensis is very low.

Incorporation of exogenous D-glucose-1-(14)C and D-manose-1-(14)C into glycogen and lactate excreted by Angiostrongylus cantonensis in vitro.

Abstract: The amount of labelled glucose incorporated into glycogen is 6 times as much as that of labelled mannose by the female worms. They excreted lactate of labelled glucose-origin 3-4 times as much as that of labelled mannose-origin. The amount of labelled glucose incorprated in worm bodies is about 3 times as much as that of labelled mannose. Male worms absorbed a half amount of glucose by female worms. Paralelled with radioactivity studies mentioned above, chemical determinations of sugars, lactate, and glycogen were performed on the media prior and posterior to incubation and the worms. The results obtained from chemical determinations fairly agreed with those on lactate production and sugar consumption from radioactivity studies, but not on glycogen content of worms after incubation. Chemical determination shows no glycogen synthesis in worms incubated in mannose media while the radioactivity of labelled mannose was detected, though it is very low in activity, from glycogen of worms in the media. Coupled with previously reported findings, results from the present study show mannose to be far less significant in the carbohydrate metabolism of Angiostrongylus cantonensis as compared with glucose.