Regular Bodies Research Articles

Changes in the surface properties of chloroplast membranes from dark-grown Pinus silvestris following illumination

The etiochloroplasts of dark-grown seedlings of Pinus silvestris contain regular prolamellar bodies, grana and stroma thylakoids, chlorophylls a and b but no protochlorophyllide or chlorophyllide. The behaviour of etioplast membranes from Pinus silvestris in polymer two-phase counter-current distribution before and after illumination is however similar to that of etioplast membranes from Pisum sativum and Avena sativum indicating that they share common properties with regard to surface activity although their pigment content varies.

Research Notes on the Changing Loci of Decision in the Chinese Communist Party

In the course of the Cultural Revolution, both Chinese official and Red Guard sources have revealed that the so-called Chung-yang kung-tso hui-i (Central Work Conference)—an institution hitherto not well known to outside observers—had met frequently during 1960–66 and that these meetings were connected with decisions on important policy issues. While its existence and jurisdiction have never been formally stipulated by the Chinese Communist Party (CCP) Constitution of 1956 or 1945, the Central Work Conference appears to have become an important locus of decision in the Party during the 1960s. There are indications that it functioned alongside of the Party's regular decision-making bodies, the Central Committee (CC) and the Politburo, and that it replaced, and possibly pre-empted, the functions of other institutional devices which Mao Tse-tung has utilized during the second half of the 1950s. This article examines briefly the participants in, and functions of, the Central Work Conference and other types of Party meetings, attempting to shed some light on the loci of decision in the CCP. Appended to the article is a list of known Party meetings from 1949–66, compiled from official and Red Guard publications, which may be of some use to students of Chinese Communist affairs.

Lamellate bodies in the nuclei of dragonfly (Odonata) oocytes.

Concentrically lamellate spherical bodies have been observed in the oocyte nuclei of the anisopterous dragonflyCordulia aenea. In their ultrastructure, these bodies resemble the “cortical granules” reported from the cytoplasm of the sea urchin oocytes. The lamellate bodies ofCordulia are compared with other lamellate systems known to exist in nuclei. It is suggested that the nuclear lamellate spheres ofCordulia may be homologous with the somewhat less regular lamellate bodies described from maize microspores.

Syncytes in Meiosis of Polyploid Sorghum1

Syncytes occurred in a triploid and tetraploid progeny of an interspecific hybrid between Sorghum bicolor and S. halepense. That they originated by the fusion of two or more microsporocytes as a result of environmental conditions of high temperature and moisture stress is suggested. Meiosis was relatively regular in material collected from the same plants during favorable growing conditions. Coalescence of pollen mother‐cells varied from complete fusion into one polyploid cell to merely peripheral connection. Although meiosis was very irregular in these fusion bodies, sufficiently regular and functional fusion bodies, sufficiently regular and functional polyploid polyploid spores could be formed which may subsequently give rise to a polyploid series within a species.

Lateral Force and Moment on Ships in Oblique Waves

A method for evaluating the exciting force and moment on surface ships as well as on fully submerged bodies in oblique waves is developed, based on the assumptions of long regular waves and slender bodies. The differential equation, together with the boundary conditions, for each component of the velocity potential is studied. Momentum theorems for slender-body sections are derived and applied to the evaluation of stripwise force and moment on bodies in the presence of a free surface. The result is found to be directly related to the added masses of the body sections. Lateral added masses of body sections in the presence of a free surface are investigated in detail and numerical values are presented for Lewis sections.

The origin and structure of brochosomes

Minute regular bodies found associated with insects and called brochosomes by previous investigators have been shown to be identical with bodies that originate in the malpighian tubules of leafhoppers. The bodies, which are regular dodecahedra with projections from each corner, are formed within the cytoplasm of the malpighian tubule cells, but their composition and their function are obscure.

Preparation of Perspective Diagrams

CONTOURED maps, serial sections, or plans and elevations, are capable of providing much detailed information about the form of regular or irregular bodies and surfaces. It is, however, not always possible, from an examination of such diagrams alone, readily to visualize the real shape of the surface and the relationships of the various parts, as the process of mental integration of the series of basic diagrams can often only be carried out after a prolonged study. Moreover, the formation of a complete mental picture, which can be easily used, may not always be possible. To overcome this difficulty, models of the surface may be constructed from the basic diagrams, and in most respects these constitute the ideal solution of the problem, since they can be viewed from many angles with ease. Unfortunately, such models are generally expensive and tedious to make1,2,3,4, besides being fragile and not easily duplicated, and, when large, not portable. As a consequence, resort is frequently made to diagrams in which it is attempted, with varying degrees of success, to convey an impression of the third dimension. These diagrams have some of the virtues of models, and at the same time they are readily reproduced and stored.

The Golgi Apparatus of Copromonas subtilis, and Euglena sp

ABSTRACT In Copromonas subtilis, Dobell, and Euglena sp. there is a Golgi apparatus consisting of osmiophil material in the form of granules, which are associated with the osmoregulatory mechanism of the cell. Inside the granules, water collects, so that they become spherical vacuoles, identical with what have in the past been called contractile vacuoles (Copromonas) or accessory contractile vacuoles (Euglena viridis). In Euglena viridis, the Golgi apparatus is closely applied to the so-called contractile vacuole, and consists of numerous loaf-shaped osmiophil bodies which undergo a regular series of changes from systole to diastole, and vice versa. In Copr omonas, the osmiophil material may form a thick cortex surrounding what has been called the reservoir, it may be attached to the reservoir in fairly regular loafshaped bodies as in Euglena, or it may be completely detached from the reservoir. The so-called contractile vacuoles of Copromonas are vesicles containing water, which are formed on the site of the osmiophil granules. As far as we are able to say at present, the reservoir of Copromonas is indistinguishable from an enlarged contractile vacuole, and new reservoirs probably arise from swollen contractile vacuoles. It is difficult to believe that the reservoir divides into two, as has been claimed by Dobell. During division of Copromonas, two reservoirs can nearly always be found in the early stages before the nucleus becomes dumb-bell shaped. These seem to have originated from the osmiophil vacuoles. The remaining osmiophil material, when present, moves slightly down the cell, occupying a place in the mid-line. When the new cell-wall between the two organisms has passed down, about one-third the length of the dividing monad, the osmiophil material splits into two sub-equal groups and is so divided between the two organisms. There is therefore a definite dictyokinesis to be found in Copromonas. Just at or after this period, the osmiophil material may become scattered about the upper middle and upper region of the dividing monads, but finally becomes situated in the region of the reservoir. The osmiophil material (Golgi apparatus) persists throughout conjugation and encystment, even when a reservoir cannot be found. There is a rhizoplast joining the basal granule of the flagellum with the intra-nuclear nucleolo-centrosome, and an axostyle is present, passing from the basal granule to the posterior end of the organism. During cell division, the basal granule divides into two and appears to lose its connexion with the two nucleolo-centro-somes of the dividing nucleus. The axostyle appears to be absorbed in the early stages of division and cannot be stained at this epoch, but reappears in each moiety of the dividing organism, when the nucleus is dumb-bell shaped. It appears to reform when the two basal granules have taken their definitive position at the anterior end of the cells. We agree with Wenyon that one flagellum passes over intact to one of the daughter cells at division, the other flagellum arises from the other basal granule. Numerous fat granules are found throughout the organism ; what have been called volutin granules in other Protozoa are present in Copro monas, and stain in neutral red. Mitochondria are present mainly in the posterior region of the organism.

Elementární odvození momentu setrvačnosti některých těles pravidelných

Elementární odvození momentu setrvačnosti některých těles pravidelných

Scientific Serials

American Journal of Mathematics, vol. xviii. No. 2, April.—The intermediary orbit, i.e. the Moon's periodic orbit relatively to the Sun obtained from the variation terms when all terms but those depending on the ratio of the mean motions only are omitted, has been considered in vol. i, by Dr. Hill, and subsequently in the Acta Manthematica (vol. viii.) the same writer obtained an expression for the motion of the Moon's perigee, so far as it depends on the ratio of the mean motions. These papers have been followed by others by Prof. E. W. Brown, in which the terms depending on the solar parallax and the lunar eccentricity are computed.—The object of the opening paper of the present number, on the inclinational terms in the Moon's coordinates, by P. H. Cowell, is to take into account, according to Dr. Hill's method, the inclination of the orbit, considering it as being the manifestation of a small oscillation about Dr. Hill's distorted circular orbit, which relatively to the Sun is a closed curve. The terms multiplied by the first power of the inclination have been calculated to the sixth order, and an expression for the part of the motion of the Moon's node, that depends upon the mean motions only, has been found as far as the eighth order, i.e. one term further than in Delaunay's series. The terms multiplied by the square of the inclination have been calculated to the fifth order, and the terms multiplied by the third power of the inclination to the fourth order in m. The notation adopted is that of the paper by Prof. Brown (Am. Journ. Math., vol. xvii.).—A short note by A. S. Chessin, on non-uniform convergence of infinite series, brings out more clearly a point in a previous note (vol. xviii. No. 1), which the writer says has been misunderstood.—On a certain class of equipotential surfaces, by B. O. Peirce, discusses the nature of such systems of plane curves as are at once the right sections of possible systems of equipotential cylindrical surfaces belonging to distributions of matter which attract, according to the law of nature, and the generating curves of possible systems of equipotential surfaces of revolution.—M. Petrovitch contributes “Remarques sur les équations de dynamique et sur le mouvement tautochrone.”—A note on C. S. Peirce's paper on a quincunclal projection of the sphere, by J. Pierpont, corrects an inaccuracy in that paper (vol. ii. p. 394). Mr. Pierpont, in a note on the invariance of the factors of composition of a substitution-group, gives a much simplified proof of this important theorem.—H. Maschke, in a long article (pp. 156-188) on the representation of finite groups, especially of the rotation—groups of the regular bodies of three-and four-dimensional space, by Cayley's colour diagrams, shows that Cayley's method (the theory of groups, graphical representation, Am. Journ., vol. i., and on the theory of groups, Am. Journ., vol xi.) can be readily applied to the construction and investigation of numerous groups of higher orders. In particular, the writer says, the colour diagrams for the rotation groups of the regular bodies can be arranged in such a way that they lend themselves much easier, at least in some respects, to a study of the groups concerned, than even the models of the regular bodies. Numerous diagrams of interest accompany the paper.

The Representation of Finite Groups, Especially of the Rotation Groups of the Regular Bodies of Three-and Four-Dimensional Space, by Cayley's Color Diagrams

The graphical representation of a group given by Cayley* leads to a diagram consisting of several lines of different colors, a so-called color-group, which affords a very clear insight into the structure of the group. Cayley himself applied his method only to groups of comparatively low orders, and it seems that the inethod has never been used for more complicated cases.t The purpose of the present paper is to show how readily Cayley's method can be applied to the construction and investigation of numerous groups of higher orders. In particular, the color diagrams for the rotation groups of the regular bodies can be arranged in such a way that they lend themselves miuch easier, at least in some respects, to a study of the groups concerned, than even the models of the regular bodies. The most prominent feature of these diagrams, to which their high degree of perspicuity is due, consists in the fact that their color lines do not intersect each other, so that the diagrams, when described on the sphere, constitute convex polyhedrons. I determine, in the first part of the paper, all the color-groups thus defined and show that, apart from two other cases, they are identical with the rotation groups of the regular bodies. In the second part I study in detail the connection between the rotation groups and the corresponding diagrams. The third part of the paper contains some extensions of the