Inert Part Research Articles

Deposition of mimics of planktonic invertebrate larvae on simple and complex substrata in flume flows

The purpose of this study was to compare the distribution of inert part~cles on polyvinylchloride (PVC) panels with earlier results from field studies. The panels were prepared in order to test heterogeneity (crevices similar in shape, but differing in size) and complexity (combination of crevices of different sizes) effects. The experiments were carried out using PVC particles and preserved Placopecten magellanjcus larvae in a flume under controlled flow conditions (mean velocities of 3, 5 and 10 cm S-') and using silicon-coated panels. The heterogeneous panels had different comblnations of flat surfaces and 1, 10 and 100 mm crevices. The density of particles per unit surface area adhering to the panels was higher at 3 and 5 cm S-' than at 10 cm S ' for all experiments. The density of adhering particles decreased with increasing panel complexity. Within panels with only 1 mm crevices, the density of particles was significantly higher inside the crevices than on smooth surfaces. However the density of particles was significantly lower in 10 and 100 mm crevices than on adjacent flat surfaces within panels with only 10 and l00 mm crevices, respectively. Furthermore, the 1 and 10 mm crevices nested inside 100 mm crevices collected fewer particles than those outside 100 mm crevices within panels with many scales of crevices. The patterns of distribution for dead larvae on heterogeneous panels in the flume corresponded to those of the inert PVC particles. However, the distribution patterns of inert particles in the flume did not correspond to those of living bivalve spat observed in an earlier fleld study. This suggests that larval behaviour contributed to the selection of settlement location for these bivalve larvae, though flume hydrodynamical conditions may differ from those in the field The results also indicate that the hydrodynamic processes affecting settlement on heterogeneous substrates are scale-dependent and that processes occurring at scales of 10 and 100 mm influence processes occurring at smaller, 1 mm, scales.

The effect of the progesterone-releasing intrauterine device on uterine endometrium and fallopian tube epithelium.

A scanning and transmission electron microscopy study was undertaken of the effect of the progesterone releasing intrauterine device (Progestasert, Alza Corporation, USA) on the uterine endometrium and fallopian tube epithelium. Small erosions of surface epithelium and microthrombosis of stromal capillaries were found in the endometrium below the inert part of the device. A reduction of ciliated cells and shortened cilia were seen in the endometrium below the active part of the device and large dilated venules were present in the underlying stroma. Fallopian tubes from IUD patients contained fewer ciliated cells than those of the controls. The morphological changes described are likely to be major factors responsible for the irregular bleeding which occurs with Progestasert IUDs and the possible increase in tubal pregnancy.

The structure of the heterochromatic part of the Y-chromosome in Drosophila buscki.

In the salivary glands of D. buscki the Y-chromosome was at first shown to be a small euchromatic element whose length is about 1/24 of the Xchromosome, and consisting of some 14-15 bands.l1 2 In ganglial metaphases, this Y-chromosome has the form of a tapering rod, narrow at the proximal end which carries a small knob-like thickening; the length is about equal to the X-chromosome. This non-correspondence between the appearance of the Y-chromosome in the two types of cells was attributed to a heterochromatic or inert part, which is greatly reduced in relation to length, or apparently absent, in salivary glands. Until recently few attempts were made to identify such heterochromatic elements in salivary gland cells. It has been shown previously that the Y-chromosome in D. buscki is necessary for the life of males: XO-males die at an early stage of the development.3-5 As a result of a comprehensive cytogenetic investigation on the Y-chromosome in D. buscki, it has been possible to clarify the role of constituent parts in some detail, and to show their action on the development of males. In particular, it has been shown that the Y-chromosome is two-armed: the right, short arm, is the knob-like thickening at the proximal end, and is the euchromatic element in the salivaries; the left, long arm, is the inert heterochromatic part (unpublished). New information concerning the structure of this inert part has also been obtained in the course of this work, and is reported in the present paper. Experimental Data.-The material for this work was the mutant line CurledY(404) obtained in an F, from crossing X-rayed males to wild type females. The ends of the wings of the mutant flies are bent upwards. This mutant behaves genetically as Y-linked, that is, it is inherited from father to son. Among the offspring of mutant males, about 10-12% of non-mutant males appear. This last class of males have a slightly shortened body, and are completely sterile. Cytological analysis of the mutant males shows a break in region 7 of IIR. The proximal part of the broken IIR usually pairs fully with its

A case of intrachromosomal translocation of an active section into the inert part in Drosophila melanogaster

A case of intrachromosomal translocation of an active section into the inert part in Drosophila melanogaster

Correlation: Its Philosophy and Practice

HE whole progress of modern thought is in the direction of recognizing the essential connectedness of everything. In Philosophy this idea finds form in the thought that everything in the universe is inevitably related to everything else. In Political Science it is now recognized in theory if not in actual practice that the countries of the world all depend on one another, and that no one people can be independent of the rest in the sense that they can plan their own affairs in disregard of the rights, the conditions, and the states of mind of other countries. Physics, Chemistry, and Geology are not independent sciences, as we used to think, but constitute a closely knit texture of codified principles and formulae with regard to the inert part of the universe. Psychology is not merely mental science as it used to be called, but rather an organized group of facts about man's behavior, including physical, mental, and emotional reactions, recognizing the essential unity and inter-connectedness of these three and basing its findings quite as much upon Zoology and Physiology as upon what used to be called pure Psychology. In Education we have been slow to put into practice the principles now so universally recognized as applying in the rest of the world. So we have continued to teach isolated subjects, taking great care lest our pupils get these various subjects mixed up. Therefore we find boys and girls who, when they read a certain play called Julius Caesar, written by a gentleman named Shakespeare, never dream that its hero is the same Julius Caesar whose Commentaries caused them so much

Components of Air in Relation to Animal Life

OXYGEN, since the time of Lavoisier, has been considered the vital component of the air: the 79.19 per cent inert part has had little use assigned it. Popular opinion had stated that animal life would be more efficient if these inert gases were replaced by oxygen. Carefully conducted experiments covering a period of six years have shown the following facts in regard to animal life and the components of the air.