Mode Of Branching Research Articles

Computer simulations of early land plant branching morphologies: canalization of patterns during evolution?

Using computer simulations and a quantitative method for describing bifurcating structures, the morphology of branching patterns seen in early land plants is analyzed. Four types or models of random branching (regular, geometric, binomial, and poisson) are shown to adequately describe the range of observed branching in most early land plants. Approximately 57% of all randomly generated computer patterns show reiterative branching events (=three successive identical modes of branching). Artificial canalization of reiterative events results in branching patterns structurally analogous with that of ancient fossil plants. Simulated phylogenetic changes among early land plant lineages, based on parsimonious transitions in branching patterns, indicate that most observed trends can be related directly to those seen in randomly generating branching patterns in which “size” is increased. The trimerophyte to progymnosperm trend in changing branching patterns is an exception, since the binomial model describing the progymnosperms has not been simulated by random processes.While the apparent phylogenetic changes among early land plant groups do not require deterministic explanations, the transition from regular to geometric branching and the “canalization” of reiterative branching patterns may represent a grade level response to selective pressures related to mechanical design and vegetative reproduction.

Stability and branching of normal oscillation forms of nonlinear systems

Essentially nonlinear conservative systems that admit single-frequency modes, i.e. normal oscillations with rectilinear trajectories are considered. In many cases the passage to consideration of trajectories in the configuration space makes possible a simplification of investigation of normal oscillation orbital stability, a problem which reduces to four Sturm-Liouville problems with equations in variations. All points of stability change of normal oscillations, which are also branching points, are determined for homogeneous systems. Various types of periodic modes of branching from normal form solutions (whether affecting or not affecting normal oscillations stability) are analyzed. The effect of mechanical characteristics of a nonlinear chain system with two degrees of freedom on the number of normal oscillation forms and their stability is studied. The obtained results are applied to nearly-homogeneous systems.

Bathymetric Zonation and Paleoecological Significance of Microborings in Puerto Rican Shelf and Slope Sediments

Sediments collected from 63 sites on the Puerto Rican shelf and slope at depths ranging from intertidal to 530 m were analyzed for associated microborings. Scanning electron microscope examination of three dimensional plastic casts of microboring networks form the primary basis for this study. In all, 27 microboring forms are distinguished on the basis of size and shape of boring casts, mode of branching, overall boring pattern and associated accessory structures. Although most of the microborings exhibit wide bathymetric ranges, many of the forms tend to occur more abundantly within restricted depth zones, suggesting a three-fold subdivision. The upper photic zone assemblage (intertidal to 20 m) is characterized by the endolithic blue-green algae Hyella gigas, Hyella caespitosa, Hyella tenuoir, Hormathonema sp., and an unidentified endolith likely of algal origin (form D). The lower photic zone assemblage (20 m - 85 m) is characterized by the green algae Ostreobium quekettii and Codiolum polyrhizum , the Conchocelis -stage of an endolithic red alga, and a problematic algal form (A). The aphotic zone is characterized by the absence of algal borings and the presence of fungal form Il and a tubular form of uncertain affinity. Microborings in the upper photic zone are typically oriented perpendicular to substrate surfaces; those of the lower photic and aphotic zones parallel substrate surfaces and penetrate only slightly into substrate interiors. Microborings as trace fossils appear to have high paleoecologic potential inasmuch as they are believed to be biologically specific and often are morphologically distinctive. Microborings have been reported in sediments ranging in age form Cambrian to Holocene with many ancient endoliths resembling extant forms. Differences in direction of penetration between photic and aphotic endolithic organisms may be sufficient criteria for differentiating paleophotic zones in ancient carbonate sequences. A Pleistocene example is presented from the Fort Thompson Formation of south Florida which indicates that impregnation techniques utilized in endolithic analysis of modern sediments may find application in studies of ancient microboring assemblages.

Plant mucilages. XXIV. The structural features of althaea-mucilage O, a representative mucous polysaccharide from the roots of Althaea officinalis.

Partial acid hydrolysis of Althaea-mucilage O, a representative mucous polysaccharide isolated from the roots of Althaea officinalis L., led to the isolation of five oligosaccharides. Analysis of their components, as well as reduction and methylation, and partial degradation studies showed that these oligosaccharides are O-α-(D-galactopyranosyluronic acid)-(1→2)-L-rhamnopyranose, O-β-(D-glucopyranosyluronic acid)-(1→3)-O-α-(D-galactopyranosyluronic acid)-(1→2)-L-rhamnopyranose, and the hexasaccharide, the nonasaccharide, and the dodecasaccharide composed of a repeating unit having the structure of the trisaccharide through position 4 of the D-galacturonic acid residue. The polysaccharide was also subjected to chromium trioxide oxidation, and to controlled Smith degradation. The configuration and the mode of branching were determined. The structural features of the mucilage are discussed.

Anatomy of the coronary arteries in transposition of the great arteries and methods for their transfer in anatomical correction.

For the success of anatomical correction of transposition of the great arteries (TGA) it is essential to transfer the coronary ostia to the posterior vessel without undue tension, torsion, or kinking of the proximal coronary arteries or their early branches. This requires thorough understanding of the different modes of origin and early branching of the coronary arteries in TGA. Based on observations made during anatomical correction, a classification of the coronary arteries in TGA is suggested. In type A the right and left coronary ostia arise from the middle of the right and left posterior aortic sinuses and curve forwards to reach the right atrioventricular groove or anterior interventricular groove respectively. In type B both coronary arteries arise by a single ostium, while in type C the two coronary ostia are situated posteriorly, very close to each other, in a position similar to that in type B. The origin of the coronary arteries in type D is similar to that of type A. However, the right coronary artery gives origin to the circumflex coronary artery that curves round the posterior (pulmonary) vessel to reach the atrioventricular groove. In type E the right coronary artery arises in common with the left anterior descending artery from the left posterior sinus, while the circumflex artery arises separately from the right posterior sinus. Three techniques for the transfer of the different types of coronary arteries during anatomical correction are described.

Axonal trajectory of single group Ia and Ib fibers in the cat spinal cord

Intracellular staining with HRP of physiologically identified group Ia and Ib afferent fibers in the adult cat lumbosacral cord revealed that group Ia and Ib fibers take a similar course in the dorsal funiculus, but the collaterals emerging from them show a different topographical distribution and a different mode of branching in the gray matter. Ia collaterals terminate in laminae VI, VII, IX, and sometimes VIII, whereas Ib collaterals terminate only in lamina VI, or both VI and IX. In lamina IX, two large motor-type neurons received terminations of both Ia and Ib fibers at the same time.

Secondary flows in a plane channel: PMM vol. 42, n≗2, 1978, pp. 361–367

Formation of the secondary self-oscillating modes of flow branching away from the Poiseuille flow in a plane channel, is investigated. Conditions of appearance of the secondary self-oscillating modes at nearly critical values of the Reynolds number were obtained earlier in [1, 2]. It was shown, in particular, that the existence of the secondary flows can be established by analyzing the linearized equations only. In the present paper the formation of secondary flows in a plane channel, periodic in x and t, is studied with help of the asymptotic solutions of the Orr — Sommerfeld equations. It is proved that in the sufficiently small neighborhood of almost every value of the Reynolds number R lying on the neutral curve of the linear theory of stability, values of R exist such that the Navier — Stokes equations have solutions periodic in x and t.

Sodium acetate tri-hydrate whiskers

A new kind of whisker, which has not been previously reported in the literature, was grown on membranes which were in contact with a saturated aqueous solution of sodium acetate, using several techniques. Cellulose acetate membranes were used in all the cases and growth was successful at 25 ± 2°C and 45–55% relative humidity. A dense colony of whiskers, sometimes stuck together in bundles, usually up to 5 cm in length and ranging in width from 0.3–100 μm, developed within 72 h of growth. The whiskers were identified as sodium acetate tri-hydrate by means of Debye-Scherrer X-ray powder method. Laue transmission photographs indicated the existence of twin crystals within the individual single crystal whiskers as proved by electron diffraction in TEM. Some whiskers included internal and external channels, and there were several secondary effects, such as thickening in the middle of a whisker, formation of arrow-heads or spirals at the tips and various modes of branching. The whisker morphology and the various growth phenomena may be explained as a whisker growth process from their bases, when we consider a continuous crystallization from material which is supplied through and over the membrane.

Studies in Geraniale: 1. The nodal organization

A study of the nodal organization of 29 members of this order revealed four nodal types: I. Trilacunar three-traced, II. Bilacunar three-traced, III. Bilacunar two-traced and IV. Unilacunar one-traced. Trilacunar three-traced condition has been observed in 25 out of 29 species investigated. Whereas bilacunar two-traced condition is represnted by some half a dozen species, bilacunar three-traced condition and unilacunar one-traced conditions have been observed only inGeranium robertianum andLinum usitatissimum respectively. It is significant to note thatGeranium robertianum in addition shows a trilacunar three-traced and bilacunar two-traced conditions. Trilacunar three-traced condition is considered to be basic for this group and it is believed that the unilacunar one-traced condition is derived by approximation and coalescence of the laterals with the median, followed by the obliteration of their gaps. Such a tendency has been observed in some members of this group and a reduction series has been traced. The mode of branching in Geraniaceae is referred to as sympodial. This has been confirmed by the behaviour of the vascular cylinder at the node.

Ultrastructural observations on branching patterns of central axons

The mode of branching of preterminal axons in the cat oculomotor nucleus was studied by electron microscopy. At many nodes of Ranvier, branching does not occur. At those nodes where branching does occur, trifurcations as well as bifurcations are present. Nodal synapses are common, and, in some cases, both pre- and postsynaptic processes are sorrounded by the myelin sheath. The data indicate that divergence of neural information may occur at trifurcations and higher-order branchings, as well as at bifurcations, and further demonstrate that divergence of neural information may occur at sites, i.e. nodal synapses, that are not discernible at the light microscopic level.

SYMMETRY AND DEVELOPMENT OF PISTILLATE VALLISNERIA AMERICANA (HYDROCHARITACEAE)

Pistillate Vallisneria americana produces upright vegetative axes and prostrate stolons and develops in a manner fundamentally similar to that of Limnobium spongia (Hydrocharitaceae) and certain other taxa of Alismatidae. The cauline portions of pistillate V. americana branch solely by the bifurcation of apical meristems, and their mode of branching offers clues concerning the nature of the plant body. The upright axes are interpreted to have sympodial growth, whereas at least certain stolons appear to be entirely monopodial. The upright axes are either typical vegetative axes or turions; and of these, only turions appear to survive the winter in at least one locality. Pistillate V. americana produces intravaginal squamules (multi‐seriate trichomes) although they appear reduced in number relative to those in certain other hydrocharitaceous and alismatid taxa. Vallisneria americana exhibits a notable degree of mirror image symmetry which differs somewhat from that of Limnobium spongia.

Floral morphology of the Amaryllidaceae. I. Subfamily Amaryllidioideae

The flowers of the subfamily Amaryllidioideae are similar to one another in that they are fragrant, showy, bisexual, and epigynous with two trimerous whorls of perianth and stamens each, and a compound gynoecium. A single vascular strand supplies the vascular system of both a perianth member and a stamen. It splits into three bundles, one median and two laterals. The former constitutes the vascular supply of a perianth member, while the latter, facing one another right and left, fuse to supply a stamen. This peculiar mode of branching of the vascular strand is considered to be associated with superposition of a stamen upon a perianth member. The corona of Narcissus which is supplied by inversely oriented vascular bundles, is regarded as an outgrowth from the perianth tube and those of Eucharis and Pancratium, which are non-vascular, to represent the stamen cup. Two series of vascular strands differentiate in all members investigated. While the inner series constitutes the placental supply, the strands of the outer series which vary in number in different genera, show various degrees of adnation among the traces occurring on the same radius. The nature of the inferior ovary has been discussed. The nectaries are considered to be of quite advanced type.

Estimation of endgroups in poly(vinyl acetate) and the corresponding poly(vinyl alcohol) to study the hydrolysis reaction

AbstractThe mode of branching in poly(vinyl acetate) has been studied using reverse dye partition (RDP) technique developed in this laboratory. It has been observed that during hydrolysis of poly(vinyl acetate) the degree of polymerization of the polymer decreases in all cases. This degradation is found to be erratic. It may be caused by the separation of branches which were connected to the main chain through ester linkage. This idea has been confirmed by the detection of average one carboxyl endgroup in the resulting shorter polymer chains.The change in the number of endgroups in the parent and the corresponding hydrolysed polymer has been used as a tool for the estimation of number of branches in poly(vinyl acetate) molecules.

Topological Index. A Newly Proposed Quantity Characterizing the Topological Nature of Structural Isomers of Saturated Hydrocarbons

Abstract A topological index Z is proposed for a connected graph G representing the carbon skeleton of a saturated hydrocarbon. The integer Z is the sum of a set of the numbers p(G,k), which is the number of ways in which such k bonds are so chosen from G that no two of them are connected. For chain molecules Z is closely related to the characteristic polynomial derived from the topological matrix. It is found that Z is correlated well with the topological nature of the carbon skeleton, i.e., the mode of branching and ring closure. Some interesting relations are found, such as a graphical representation of the Fibonacci numbers and a composition principle for counting Z. Correlation of Z with boiling points of saturated hydrocarbons is pointed out.

The "receptor surface" of the olfactory organ (epithelium) of man and guinea pig. A descriptive and experimental study.

A superstructure for the olfactory epithelium is described. The interrelationship of its cellular constituents and their relationship to the free surface of the epithelium is demonstrated. The microvilli in the olfactory region of man are shown to contain an array of filaments, whose pattern of distribution is demonstrated; their mode of branching is discussed. A distinct receptor zone consisting of the terminal processes of the peripheral olfactory neurones forming the outer third of the superstructure of the olfactory epithelium in the experimental mammals is demonstrated. Experimentally induced damage results in swelling and ultimate disintegration of these processes and invariably leads to the disappearance of the receptor zone. There occurs hypertrophy and increase in the number of microvilli of the supporting cells; physio-pathological deformities of their free surfaces are occasionally seen. Later events are recorded and at a week the appearance of the receptor end of the olfactory epithelium is shown.

Revision of the Systematic Position of Saprochaete Saccharophila

SUMMARY Saprochaete saccharophila, described in 1939 and placed in the Chlorophyta, is validated and belongs in the Fungi Imperfecti based on fungal characteristics revealed by recent electron microscope, X-ray diffraction, and bio-assay studies. In 1939 Coker and Shanor described Saprochaete saccharophila Coker & Shanor as a saprophytic fungoid alga. On the basis of such morphological features as mode of branching (FIG. 1), rhizoidal holdfasts and cell wall composition, they placed it among the algae near the Chaetophoraceae. But the plant is devoid of chlorophyll and any trace of plastids (FIGS. 2-4). Smith (5) argued against placing Saprochaete in the Chlorophyta because of the presence of a glycogen-like substance which has been shown to be present by the positive reaction with I2KI (1, 7, 8). In 1955, Vischenevskaja (6) described a new species of the genus Saprochaete placing it in the Fungi Imperfecti. However, Lewin (3), in fact, suggested that Saprochaete should be examined biochemically before any definite assignment of its taxonomic position can be made. Dawes' (2) studies of S. saccharophila involved use of light and electron microscopes, X-ray diffraction, microchemical tests and biochemical assay with chitinase. He found the cell structure to be eucaryotic noting that mitochondria, nuclei, lipid bodies, endoplasmic reticulum, and micro

The capillary in the human cochlea.

The capillary area of eighteen aged human cochleas was studied using an alkaline phosphatasc staining method. The technique is described in detail. Modes of capillary branching in the spiral lamina were different from turn to turn. The vas spirale, a loop capillary vessel beneath the tunnel of Corti, was long in the basal turn and short in the upper turn. The spiral lamina of the upper turn was more vascularized than that of the basal turn. A morphometric measurement showed that the ratio of capillary density at the areas of 25 mm and 5 mm was 1.5. The significance of the findings is discussed in connection with the vulnerability of the basal turn of the cochlea in sensori-neural deafness.

Comparative angiographic and corrosion cast studies of the cervicocerebral arteries in the dog.

Roentgen anatomy of the cervicocerebral circulation in the dog has been studied through arteriograms and methyl methacrylate corrosion specimens. Discrepancies from the classic description of the canine cervicocerebral circulation were observed in the present study. These involved the mode of branching of the vertebral arteries and the formation of the ventral spinal artery. The role of these vessels in the formation of the basilar artery is also noted. A more descriptive terminology is suggested for the arteries of this region. Such anatomic variations may play a vital role in the arterial supply to the dog's spinal cord, brain stem and cerebral cortex. These experiments rule out the presence of a carotid rete between the external carotid and internal carotid circulation before the formation of the arterial circle of the brain. Emphasis is on the importance of the internal carotid artery in the formation of the arterial circle of the brain in the dog.

オオハリガネゴケの胞子発芽と原糸体生長に関する形態学的および生理学的観察

(1) The physiological and morphological observations on the spore germination and the protonematal growth in Bryum pseudo-triquetrum were performed under controlled conditions.(2) The prostrate protonematal system as well as its erect aerial filaments showed a widely divergent morphology between typical chloronema and primary rhizoid. Some of the filaments grew plagiogeotropically and their physiological dorsiventrality was found by the mode of branching.(3) The sporeling could normally develop on media containing Ca(NO3)2, K2HPO4 and MgSO4. The optimal concentrations of each salt for both the germination and the growth, when examined by the system where other minerals besides the subjected one were fixed in a certain level, were determined to be 5×10-3, 1-5×10-3 and 1×10-3M, respectively (the standard medium). The additional applications of (NH4)2SO4, H3BO3 and FeCl3 to the standard medium had no effects.(4) IAA at 10-2-1ppm promoted the growth, whereas gibberellin was rather inhibitory at 10-3ppm or more.(5) The initial pH of the media favored the growth and the germination existed at the range between 5 and 9. The growth was better in alkaline range than acidic.(6) The optimal temperature for the germination and the growth existed between 21°and 25°.(7) The light needed for the germination and the growth were saturated at the range higher than 480Lux. The critical day length for the germination of the spores collected in 1965 laid in about four hours.(8) The spores maintained their germinating ability for nearly three years. Fig. 8. Depression of germinating ability of spores with time. Each circle shows the germinating rate of spores from one capsule.

Two multiramous graptoloids from the lower didymograptus shale of Scandinavia

Abstract A pyritized specimen of Goniograptus sp. is described from the Lower Didymograptus Shale of Jamtland, northern Sweden. This is the first record of an undoubted Goniograptus from northern Europe. The probable mode of branching of the stipes is described from observations on an internal mould preserved in full relief. The morphology and taxonomy of the Lower Ordovician graptoloids with prothecal folds is treated in some detail. This group, which possibly can be traced back into Upper Tremadocian strata, is included in the family Sinograptidae Mu, 1957. Evidence is summarized which indicates that the sinograptids are the probable ancestors of the Dicranograptidae and that the Leptograptidae are probably derived independently from some extensiform didymograptids of the family Dichograptidae. The new generic name Cymatograptus (type species: Didymograptus undulatus Tornquist) is proposed for bira‐mous sinograptids with simple thecae of the dichograptid type. A new quadriramous sinograptid genus Oslogr...