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Showing papers by "University of Bremen published in 1988"


Book
01 Aug 1988
TL;DR: Fractal Modelling of Real World Images and a Unified Approach to Fractal Curves and Plants are studied.
Abstract: Contents: Foreword: People and Events Behind the "Science of Fractal Images".- Fractals in Nature: From Characterization to Simulation.- Algorithms for Random Fractals.- Color Plates and Captions.- Fractal Patterns Arising in Chaotic Dynamical Systems.- Fantastic Deterministic Fractals.- Fractal Modelling of Real World Images.- Fractal Landscapes Without Creases and with Rivers.- An Eye for Fractals.- A Unified Approach to Fractal Curves and Plants.- Exploring the Mandelbrot Set.- Bibliography.- Index.

1,752 citations


Journal ArticleDOI
01 Jan 1988-Nature
TL;DR: In this article, a multi-year sediment trap was deployed in the Weddell Sea, where the annual particle flux measured was the smallest yet observed in the world ocean, and showed extreme variability.
Abstract: In the Weddell Sea, primary production varies seasonally as a result of the solar cycle and the large-scale oscillation of the ice edge across much of its area. The annual ice transgression is the largest of any region on Earth1 and has a profound influence on the production and transportation of particulate matter. In order to clarify the flux, origin and mode of vertical transport of oceanic particles in the pelagic Weddell Sea, we deployed a multi-year sediment trap. The annual particle flux measured was the smallest yet observed in the world ocean, and showed extreme variability. Phytoplankton production is at least partly seeded by diatoms released from the melting of sea ice which had formed in the coastal area of the Antarctic continent. Phytoplankton production under the winter pack ice appears to be minimal.

251 citations


Journal ArticleDOI
TL;DR: In this article, time-series sediment traps were deployed at 494 and 1588 m water depth in Bransfield Strait from 1 December, 1983 to 25 November, 1984.

237 citations


Journal ArticleDOI
TL;DR: In this article, the interaction of two vortex pairs is investigated analytically and by numerical experiments from the vantage point of dynamical-systems theory, and a formal reduction to two degrees of freedom by canonical transformations and an identification and discussion of integrable cases of which one is apparently new are given.
Abstract: The interaction of two vortex pairs is investigated analytically and by numerical experiments from the vantage point of dynamical-systems theory. Vortex pairs can escape to infinity, so the phase space of this system is unbounded in contrast to that of four identical vortices investigated previously. Chaotic motion is nevertheless possible both for ‘bound states’ of the system and for ‘scattering states’. For the bound states standard Poincare section techniques suffice. For scattering states chaos appears as complex structure in the numerically generated plot of scattering angle against impact parameter. Interpretations of physical space mechanisms leading to chaos are given. Analytical characterizations of the system include a formal reduction to two degrees of freedom by canonical transformations and an identification and discussion of integrable cases of which one is apparently new.

140 citations


Journal ArticleDOI
TL;DR: The results of cell morphology and physiology studies indicated that all eight characterized communities were very different from one another and very diversely structured.
Abstract: Bacterial cell numbers obtained from 103 water and sediment samples from a Pleistocene sandy aquifer in the Lower Rhine region (Bocholt, FRG) were determinated on P-agar and by direct count. Below 5 m under the surface, colony-forming unit (cfu) numbers in water samples were less than 100/ml, and in many cases less than 50/ml. In sediment samples, they were 10- to 100-fold higher (10(2)-10(4) cfu/g dry wt), but changing markedly between different depths. Direct cell counts yielded numbers two to three orders of magnitude higher.About 2,700 strains of bacteria from 60 samples were isolated randomly and characterized by morphological and physiological properties. Of all the isolates, 71.6% were gram-negative, and 52.2% were gram-negative straight rods. Water communities, with one exception, had low proportions of gram-positive bacteria (<11%), whereas in all but one of the sediment communities percentages of gram-positive isolates were three- to sevenfold higher (35-43%). Water and sediment communities, as well as communities from different sampling sites and communities from different depths of the same sampling site, differed in their qualitative and quantitative morphotype composition and physiological capabilities.The in vitro activities of strains within a single community were quite different, indicating that each community is composed of many diverse bacteria, several having extremely different capabilities. Thus, each community has its own specific activity pattern. Gram-positive bacteria showed on an average lower total activities than did gram-negative bacteria. Grampositive bacteria as well as gram-negative bacteria from sediment had higher values of in vitro activities than the corresponding groups isolated from water. Many water and sediment bacteria preferred the same substrates which were utilized at high rates. However, there were differences in the degradation of the various other substrates present, and each community showed preferences for particular substrates, which they degraded best.The results of cell morphology and physiology studies indicated that all eight characterized communities were very different from one another and very diversely structured.

127 citations


Journal ArticleDOI
TL;DR: A strong correlation was found between cell uptake and distribution into octanol, and none of the other factors could be correlated with cell uptake.
Abstract: — For a variety of chemically defined, synthetic and natural porphyrins, the tendency for self aggregation, binding to serum albumin, distribution coefficient betweenoctanol–1 and water and uptake in V79 Chinese hamster cells have been determined. A strong correlation was found between cell uptake and distribution into octanol. None of the other factors could be correlated with cell uptake. These observations might have an impact on the use of porphyrins in photodynamic and boron neutron capture therapy of tumors.

96 citations


Journal ArticleDOI
01 Aug 1988
TL;DR: In this paper, a sediment trap deployed for one year at 473 m above the sea floor in water 2123 m deep at a station located at 75°N, 11°E, southwest of Spitsbergen.
Abstract: Monthly samples were collected by a sediment trap deployed for one year at 473 m above the sea floor in water 2123 m deep at a station located at 75°N, 11°E, southwest of Spitsbergen. This station was positioned at the northernmost extension of the Norwegian Current and was not covered by sea ice throughout the year of the experiment. The annual particle flux was 28.3 g m−2, of which 49% was biogenic and 51% was lithogenic particles. The annual fluxes of organic carbon, calcium carbonate, and biogenic opal were 2.9, 6.6 and 2.0 g m−2, respectively. Biogenic particles settling in the northern Norwegian Sea are dominated by carbonate, not opal. There were three distinct seasonality phases in sedimentation: phase 1, May to July was a period of relatively small flux, reflecting the spring bloom material in the surface layer; phase 2, August to November, showed the largest flux of carbon and other biogenic particles; and phase 3, December to May, was a period of outburst of lithogenic particle sedimentation which peaked during mid-January to mid-February. We assume that this outburst is related to cold deep water generated on the Barents Sea shelf and flowing southwestward through the Storfjord Trough into the Norwegian Sea.

92 citations


Journal ArticleDOI
TL;DR: By means of a singular perturbation scheme and large deviation estimates, this article expanded the Lyapunov exponent and rotation number in terms of the noise intensity for all systems for which A is complex diagonalizable.
Abstract: By means of a singular perturbation scheme and large deviation estimates we expand the Lyapunov exponent and rotation number in terms of the (small) noise intensity $\varepsilon $ for all $2 \times 2$ systems $dX_t^\varepsilon = AX_t^\varepsilon dt + \sqrt \varepsilon \sum olimits_{k = 1}^r {B_k } X_t^\varepsilon \circ dW_t^k $ for which A is complex diagonalizable. Examples are given.

87 citations


Book ChapterDOI
01 Jan 1988
TL;DR: In this paper, a review describes the methods used to prepare polymer coatings on a carrier electrode and discusses various ways of controlling electron processes, including electron transport through the polymer layer, catalysis at the interface, charge storage for polymer batteries, display devices and polymer-based electronics.
Abstract: Polymer modified electrodes form a new field that combines polymer chemistry with electrochemistry and which aims at developing new materials for electrocatalysis, electronics, photoelectrochemistry and photoelectronics. This review describes the methods used to prepare polymer coatings on a carrier electrode and discusses various ways of controlling electron processes. The subjects treated include electron transport through the polymer layer, catalysis at the interface, charge storage for polymer batteries, display devices and polymer-based electronics. A central topic is electron pumping in the polymer layer by photophysical and photochemical processes activated by visible light. Several prospective applications are mentioned.

83 citations


Journal ArticleDOI
TL;DR: This paper presents a method of isolation and morphological and physiological characterization of groundwater bacteria based on numerical taxonomy and cluster analysis, and using a miniaturized test system (microtiter plates).
Abstract: In this paper we present a method of isolation and morphological and physiological characterization of groundwater bacteria based on numerical taxonomy and cluster analysis, and using a miniaturized test system (microtiter plates). Bacteria were isolated randomly on P-agar, and each strain was characterized in regard to 155 features. The media for biochemical differentiation are listed as well as methods of morphological discrimination. 246 strains of heterotrophic and oligotrophic bacteria, isolated from five water samples from different depths of the saturated groundwater area, were used for optimizing media and test reactions.

71 citations


Journal ArticleDOI
TL;DR: In this article, the authors used the phase-Doppler-difference method for absolute measurements of the particle sizes and velocities from these data also predictions of the local particle fluxes and the particles' kinetic energy fluxes.
Abstract: In the wide field of fluid mechanics and multiphase flows, particle characterization plays an important role for massmomentum- and energy-balances. Using the phase-Doppler-difference method for absolute measurements of the particle sizes and velocities from these data also predictions of the local particle fluxes and the particles' kinetic energy fluxes are possible. A description of the method will be given and the required optical and electronical equipment for these measurements and for the appropriate data presentation, will be discussed.

Journal ArticleDOI
TL;DR: A reciprocal balanced translocation t(11;19)(q21;p13.1) as the sole clonal abnormality was found in the majority of metaphases, and the proliferation of epithelial cells was observed in the cultures, which should stimulate further efforts for cytogenetic investigations of the epithelial part.

Journal ArticleDOI
TL;DR: Descending projections to the medulla oblongata and rostral medulla spinalis have been examined in the urodele Salamandra salamandra with retrograde horseradish peroxidase tracing.
Abstract: Descending projections to the medulla oblongata and rostral medulla spinalis have been examined in the urodele Salamandra salamandra with retrograde horseradish peroxidase tracing. Ipsilateral projections originate from the striatum and the nucleus ventrolateralis thalami and reach the medulla oblongata. The ipsilateral nucleus praeopticus magnocellularis reaches the medulla spinalis. The rostral part of the nucleus tuberculi posterioris projects to the ipsilateral medulla oblongata; its caudal part projects further caudally. Tectal efferents and the efferents of the nucleus praetectalis profundus project bilaterally, the nucleus praetectalis superficialis, nucleus mesencephalicus nervi trigemini, torus semicircularis, nucleus Darkschewitsch, and nucleus fasciculi longitudinalis medialis project ipsilaterally to the medulla oblongata. The nucleus mesencephalicus nervi trigemini, nucleus fasciculi longitudinalis medialis, and tectal efferents reach the rostral medulla spinalis. The nucleus ruber projects mainly via the contralateral dorsolateral funiculus to the medulla spinalis. A largely crossed medullary projection arises in the nucleus dorsalis tegmenti pars anterior, a bilateral projection arises in the nucleus dorsalis tegmenti pars posterior, and an ipsilateral projection arises in the nucleus ventralis tegmenti pars anterior. Cerebellar and statoacoustic efferents descend to the medulla spinalis. The nucleus reticularis isthmi, superior, medius and inferior as well as the nucleus raphes exhibit spinal trajectories. The nucleus vestibularis magnocellularis projects bilaterally, the nucleus vestibularis medialis projects ipsilaterally spinalward. The supposed nucleus descendens nervi trigemini descends mainly contralaterally. A small spinal projection arises in the nucleus tractus solitarii. The results indicate that salamander brains display elaborate descending connections which are similar to those in other vertebrates despite their scarcely differentiated neuronal cytoarchitecture.

Journal ArticleDOI
TL;DR: In this paper, a low-insertion-loss E-plane stub-loaded rectangular waveguide phase shifters are designed with the method of field expansion into normalized eigenmodes, which includes higher-order mode interaction between the step discontinuities.
Abstract: Broadband low-insertion-loss E-plane stub-loaded rectangular waveguide phase shifters are designed with the method of field expansion into normalized eigenmodes, which includes higher-order mode interaction between the step discontinuities. Computer-optimized three-stub prototypes of 90 degrees differential phase shift with reference to an empty waveguide of appropriate length, designed for R140-band (12.4-18 GHz) and R320-band (26.5-40 GHz) waveguides, achieve typically +or-0.5 degrees phase shift deviation within about 20% bandwidth. For two-stub designs, the corresponding values are about +2.5 degrees /-1 degrees and 17%. Both designs achieve minimum return loss of 30 dB. The theory is verified by measurements of a compact R120-band (10-15 GHz) waveguide phase shifter design example milled from a solid block, showing measured insertion loss of about 0.1 dB and about +2.5 degrees /-0.5 degrees phase error between 10.7 and 12.7 GHz. >

Proceedings ArticleDOI
07 Dec 1988
TL;DR: Structured real perturbations of the system matrix A to A+ Delta A=BDC (with B, C given matrices) are considered and robustness measures with respect to arbitrary stability domains C/sub g/ contained in/implied by C are introduced and characterized.
Abstract: Structured real perturbations of the system matrix A to A+ Delta A=BDC (with B, C given matrices) are considered. Robustness measures with respect to arbitrary stability domains C/sub g/ contained in/implied by C are introduced and characterized. These general formulas provide insight but are difficult to evaluate. Computable formulas are obtained when B is a column or C a row vector. >

Book ChapterDOI
TL;DR: The theory of complex dynamical systems on the sphere was developed by G.Julia and P.Fatou at the beginning of this century, and continued by several mathematicians in recent years.
Abstract: This article is devoted to the discussion of Newton's method. Beginning with the old results of A.Cayley and E.Schroder we proceed to the theory of complex dynamical systems on the sphere, which was developed by G.Julia and P.Fatou at the beginning of this century, and continued by several mathematicians in recent years.

Journal ArticleDOI
TL;DR: The theoretical and methodological issues involved in the social shaping of technology and work, with particular reference to human centred computer integrated manufacturing (CIM) systems are decribed.
Abstract: This paper decribes the theoretical and methodological issues involved in the social shaping of technology and work, with particular reference to human centred computer integrated manufacturing (CIM) systems. Conventional approaches to the understanding and shaping of the relationship between technology, work and human development are criticised, and an alternative, human centred approach is outlined. The methods and processes whereby the design of human centred CIM systems may be shaped and evaluated are then described and appraised.

01 Aug 1988
TL;DR: Jungle evaluation turns out to be a compromise between term rewriting and graph rewriting displaying some favorable properties, and a good part of the existing graph grammar theory is applicable so that there is some hope that the rich theory of term rewriting is not lost forever without a substitute.
Abstract: Jungle evaluation is proposed as a new graph rewriting approach to the evaluation of functional expressions and, in particular, of algebraically specified operations. Jungles being intuitively forests of coalesced trees with shared substructures are certain acyclic hypergraphs (or equivalently, bipartite graphs) the nodes and edges of which are labeled with the sorts and operation symbols of a signature. Jungles are manipulated and evaluated by the application of jungle rewrite rules, which generalize equations or, more exactly, term rewrite rules. Indeed, jungle evaluation turns out to be a compromise between term rewriting and graph rewriting displaying some favorable properties: the inefficiency of term rewriting is partly avoided while the possibility of structural induction is maintained, and a good part of the existing graph grammar theory is applicable so that there is some hope that the rich theory of term rewriting is not lost forever without a substitute.

Journal ArticleDOI
TL;DR: Primary olfactory and vomeronasal projections as well as the pathway of the nervus terminalis were studied in 10 representative species of salamandrid and plethodontid salamanders by means of injections of horseradish peroxidase and examination of whole-mount preparations.
Abstract: Primary olfactory and vomeronasal projections as well as the pathway of the nervus terminalis were studied in 10 representative species of salamandrid and plethodontid salamanders by means of injections of horseradish peroxidase and examination of whole-mount preparations. Olfactory projections are very similar in the different urodeles, but vomeronasal projections differ in shape and number of termination fields. Whereas the direct-developing Plethodontini and Bolitoglossini reveal only one or two fields, the salamandrid species and the members of the plethodontid tribes Desmognathinae and Hemidactyliini, all possessing an aquatic larval stage, exhibit several vomeronasal projection fields. In all species examined centrifugal axons of the nervus terminalis leave the olfactory projection area ventrocaudally and terminate in the preoptic region and the hypothalamus.

Journal ArticleDOI
TL;DR: Plasma melatonin was determined in samples of patients with colorectal carcinoma and in controls using an iodinated radioimmunoassay and during the night, melatonin concentration in cancer patients was significantly lower than in controls.
Abstract: Plasma melatonin was determined in samples of patients with colorectal carcinoma and in controls using an iodinated radioimmunoassay Both groups showed large individual variability in absolute melatonin levels However, during the night, melatonin concentration in cancer patients was significantly lower than in controls

Book ChapterDOI
21 Mar 1988
TL;DR: A data structure, decomposition trees, is introduced, which enables graphs to be represented in a certain structured way, and which leads to simple, recursive algorithms for many difficult graph problems.
Abstract: A data structure, decomposition trees, is introduced, which enables graphs to be represented in a certain structured way, and which leads to simple, recursive algorithms for many difficult graph problems.

Journal ArticleDOI
TL;DR: In this paper, a rigorous field-theory-based design of a class of rectangular waveguide slit-coupled H-plane T-junction diplexers utilizing E-plane metal-insert filters is described.
Abstract: The rigorous field-theory-based design of a class of rectangular waveguide slit-coupled H-plane T-junction diplexers utilizing E-plane metal-insert filters is described. The filter elements allow low-cost manufacturing by accurate and inexpensive metal-etching techniques. The design method is based on a field expansion in suitably normalized eigenmodes which yields the modal scattering matrices of the three key building blocks used: the E-plane metal-insert section, the H-plane iris discontinuity, and the H-plane T. The theory includes the finite thickness of the diaphragms as well as the higher order mode interaction of all discontinuities within the complete diplexer structure. Computer-optimized design data for diplexer examples in Ku-band (12-18 GHz) and E-band (60-90 GHz), designed for more than 23-dB common port return losses, are given. The theory is verified by measured results for a five-resonator Ku-band diplexer. >

Journal ArticleDOI
TL;DR: A comparative study on the in vivo measurement of the cytoplasmic pH of Dunaliella cells was carried out, using the so-called dimethyloxazolidine-2,4-dione (DMO) method (distribution of a weak acid between the cells and the medium) and 31P-NMR spectroscopy.
Abstract: In connection with investigations of the pH-stat mechanism of the unicellular, halotolerant green algae Dunaliella parva and the acid-resistant species D. acidophila, a comparative study on the in vivo measurement of the cytoplasmic pH of Dunaliella cells was carried out, using the so-called dimethyloxazolidine-2,4-dione (DMO) method (distribution of a weak acid between the cells and the medium) and 31P-NMR spectroscopy. As judged by the effects of the external pH, light, anaerobiosis, nitrogen nutrition, permeable weak acids and bases and of ATPase inhibitors, both methods yield reproducible and in principle similar results, although absolute pH values obtained by the NMR method were always slightly higher than those obtained by the DMO method: 1) D. parva is able to maintain a cytoplasmic pH close to 7.0 at external pH 5–8, whereas D. acidophila maintains a neutral pH even at an external pH of 1. 2) The pH-homeostasis requires ATP. 3) During illumination the cytoplasm and the stroma is alkalized. 4) Anaerobiosis induces reversible acidifications of the cells. The physiological importance of these effects is discussed. Advantages of the NMR method for the assessment of the cytoplasmic pH of D. parva are: 1) Better resolution of kinetic effects. 2) Independence of volume determinations. 3) Information about phosphate, phosphomonoester, nucleotide and polyphosphate contents of the cells. However, the ability of 31P-NMR spectroscopy to monitor pH values in different compartments of cells could not be exploited with Dunaliella cells: Although a light-induced alkalization of the cells was observed, differences in the pH of the cytoplasm and the stroma of illuminated cells could not be detected. The disadvantages of the 31P-NMR method are the low sensitivity in comparison to the DMO method and the requirement for an appropriate calibration matrix. Advantages of the DMO method are the high sensitivity and the possibility of measuring many samples in parallel. Disadvantages of the DMO method are the poor resolution of kinetic effects and the need to know the osmotic volume of the cells.

Journal ArticleDOI
TL;DR: The structure of the polymers was thoroughly discussed on the basis of their IR and UV/VIS spectra as mentioned in this paper, and it was shown that the structurally uniform polymers consist of phthalocyanine moieties.
Abstract: Phthalocyanine moieties containing polymers 3 a – e were prepared by the reaction of several oxy- and arylenedioxy-bridged diphthalonitriles 2 a – e in the absence or the presence of metal salts or metals. The structure of the polymers was thoroughly discussed on the basis of their IR and UV/VIS spectra. According to the nitrile end groups determined by IR spectroscopy, the structurally uniform polymers consist of phthalocyanine moieties. Saponification of the nitrile end groups of 3 a – e leads to polymeric phthalocyanines with carboxylic acid end groups with a lower degree of annulation than that of the polymers before saponification. The low-molecular-weight phthalocyanines 5a, b were prepared as model compounds for the polymers.

Journal ArticleDOI
TL;DR: Functional evidence that kinase activity involving protein phosphorylation is required in cAMP‐mediated gene expression in mammalian cells is provided.

Journal ArticleDOI
TL;DR: During their evolution, many species of lungless salamanders have experienced a great increase in genome size and consequently in the size of their cells, including sensory receptors and neurons, and some have become extremely miniaturized.
Abstract: During their evolution, many species of lungless salamanders (fam. Plethodontidae) have experienced a great increase in genome size and consequently in the size of their cells, including sensory receptors and neurons. In addition, some have become extremely miniaturized. The consequences of these events and the morphological compensatory processes are studied in the visual system of juvenile and adult salamanders.

Book ChapterDOI
11 Jul 1988
TL;DR: In this article, it was shown that a large class of boundary node-label controlled (BNLC) and hyperedge replacement (HR) grammars are close to context-free string languages, which implies the existence of efficient sequential and parallel recognition algorithms for these languages.
Abstract: A number of different graph grammar types have been called ”context-free” in the literature We consider two recent such formalisms, boundary node-label controlled (BNLC) and hyperedge replacement (HR) grammars, from a complexity-theoretical point of view It is shown that all HR languages, the members of which satisfy a certain separability restriction, are contained in LOGCFL, the class of sets which are log-space reducible to context-free (string) languages In particular, this implies the existence of efficient sequential as well as parallel recognition algorithms for these languages Since HR grammars can simulate a large class of BNLC grammars, the same holds for an according class of BNLC languages Thus, in a sense, a large class of BNLC and HR languages are ”close” to context-free string languages

Journal ArticleDOI
TL;DR: In this paper, unprotected nucleosides were thiophosphorylated with thlophosphorousl chloride in trlalkyl phosphates and directly cycllzed by alkali hydroxide in aqueous acetonftrile to give the diaslereomers 3, 5'- cyclic cyclic phosphorothioates in good yields.

Journal ArticleDOI
TL;DR: The distribution and cytoarchitecture of motor nuclei of the cervical spinal cord were studied by using HRP techniques in 22 species of salamanders representing a wide variety of life histories and functional modes of feeding.
Abstract: The distribution and cytoarchitecture of motor nuclei of the cervical spinal cord were studied by using HRP techniques (whole mounts and sections) in 22 species of salamanders (families Hynobiidae, Dicamptodontidae, Ambystomatidae, Salamandridae, and Plethodontidae) representing a wide variety of life histories and functional modes of feeding. The nucleus of the first spinal nerve extends from the level of, or slightly caudad to, the root of the tenth cranial nerve, almost to the ventral root of the second spinal nerve. Approximately one-half of this nucleus is situated in the brainstem. This anterior extension is longest in bolitoglossine plethodontids. The nucleus of the second spinal nerve extends from the root of the first spinal nerve to the dorsal root of the second spinal nerve. The nuclei of the first and second spinal nerves in all species except bolitoglossines have motor neurons arranged in two columns: a lateral one containing large spindle-shaped cells and a medial one containing pear-shaped or polygonal smaller cells. The primary dendrites of these lateral and medial cells are parallel and their arborization is relatively narrow. In contrast, bolitoglossines lack the lateral motor column. The nucleus of the first spinal nerve consists only of a medial band of pear-shaped and sometimes polygonal cells, and the nucleus of the second spinal nerve is a wider band of pear-shaped and polygonal cells which are always situated inside the periventricular gray matter. The arrangement of the somata in bolitoglossines is less organized and the primary dendrites are less parallel and have a broader arborization than in other salamanders. In all species, cells in the second spinal nucleus are arranged in a less orderly manner than those in the first. All salamanders studied possess a spinal accessory nerve whose motor neurons are located in the cervical spinal cord; the axons leave the brainstem with fibers of the vagus nerve. The rostrocaudal extent of this nucleus differs markedly among species. In bolitoglossines the nucleus is more or less restricted to the region of the nucleus of the second spinal nerve. In all other species studied, the accessory nucleus extends from the obex to the caudal end of the nucleus of the third spinal nerve. In the tribe Plethodontini the cytoarchitecture of the accessory nucleus is similar to that of the second spinal. In desmognathine and hemidactyliine plethodontids as well as in all nonplethodontid species studied the nucleus consists of pear-shaped and cone-shaped cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Book ChapterDOI
14 Nov 1988
TL;DR: Jungles are acyclic hypergraphs that represent sets of terms over a signature so that equal subterms can be shared.
Abstract: Jungles are acyclic hypergraphs that represent sets of terms over a signature so that equal subterms can be shared.