Showing papers by "University of Hamburg published in 1976"

Integrable Hamiltonian systems and interactions through quadratic constraints

Abstract: O n -invariant classical relativistic field theories in one time and one space dimension with interactions that are entirely due to quadratic constraints are shown to be closely related to integrable Hamiltonian systems.

A parametric wave prediction model

Abstract: Measurements of fetch-limited wave spectra from various sources indicate an approximate invariance of the normalized spectral shape with fetch. It has been suggested from investigations of the spectral energy balance that this can be explained by the shape-stabilizing influence of nonlinear resonant wave-wave interactions, which are also responsible for the migration of the spectral peak to lower frequencies. Analyses of a series of further data sets obtained under non-uniform, non-stationary wind conditions show that the invariance of the spectral shape is not restricted to uniform-wind, fetch-limited situations, but applies generally for a growing wind sea. The observed shape invariance is exploited in a wave prediction model by projecting the full transport equation for the two-dimensional spectral continuum onto two variables characterizing the energy and frequency scales of the spectrum. Inspection of the resultant equations reveals further simplifications, enabling the system to be reduced ...

Lymphoblastic lymphoma of convoluted or acid phosphatase type-a tumor of T precursor cells.

Abstract: Five lymphatic neoplasms with strong focal acid phosphatase reactivity were selected from a group of acute lymphocytic leukemias and lymphoblastic lymphomas. All five cases showed an anterior mediastinal mass and exhibited identical morphology. This type of lymphoma has been described by Lukes under the term "malignant lymphoma of convoluted lymphocytes". Analysis of surface membrane receptors revealed that the tumor cells lacked surface immunoglobulin and receptors for Fc-fragment, but possessed receptors for complement (C3), untreated SRBC (ES) and SRBC treated with neuraminidase (ESN). By applying a mixed rosette assay using nucleated chicken erythrocytes coated with antibodies and C3, and denucleated ESN, it was found that a considerable number of tumor cells in all five cases formed mixed rosettes, i.e. that they bore the C3 receptor characteristic of B cells and simultaneously the E receptor characteristic of T cells. Thus the tumor cells resembled immature thymocytes of 10-15 weeks' gestation, which also show focal acid phosphatase reactivity and simultaneous expression of C3 and E receptors.

Stratified waters as a key to the past

Abstract: Density stratification in lakes and oceans generate anoxic conditions below the pycnocline, and sediment facies mirror this development. A comparison of modern sediments deposited in stratified and non-stratified waters with sediments formed since the Cambrian reveals that the ancient sea has been stratified a number of times.

Nonlinear energy transfer and the energy balance of the internal wave field in the deep ocean

Abstract: The source function describing the energy transfer between the components of the internal wave spectrum due to nonlinear interactions is derived from the Lagrangian of the fluid motion and evaluated numerically for the spectral models of Garrett & Munk (1972a, 1975). The characteristic time scales of the transfer are found to be typically of the order of some days, so that nonlinear interactions will play an important role in the energy balance of the wave field. Thus implications of the nonlinear transfer within the spectrum for generation and dissipation processes are considered.

Growth of Nitrobacter in the presence of organic matter. I. Mixotrophic growth.

Abstract: 1. Culture filtrates of heterotrophic bacteria were tested for their stimulatory effect on nitrification of three strains of Nitrobacter. 2. Yeast extract-peptone solution, in which Pseudomonas fluorescens had grown, after removal of the cells was added to autotrophically growing cultures of Nitrobacter agilis; it caused a stimulated nitrite oxidation and growth of Nitrobacter agilis. 3. The degree of stimulation depended on: a) the proportion of the culture filtrate to the autotrophic medium; b) the composition of the complex medium in which Pseudomonas fluorescens had been grown; c) the time the heterotrophic bacterium had been grown in the complex medium. 4. The stimulatory effect was highest with Nitrobacter agilis, less with Nitrobacter winogradskyi and negligible with Nitrobacter K4. 5. It was possible to adapt nitrifying cells of Nitrobacter agilis to higher concentrations of yeast extract and peptone. After the nitrite had been completely oxidized the cell-N still increased up to 30% before growth stopped.

Lymphatic absorption and metabolism of orally administered testosterone undecanoate in man.

Abstract: [3H]-testosterone undecanoate ([3H]TU) was administered orally to 4 patients with a thoracic duct catheter after neck dissection surgery. Appearance of radioactivity in lymph, plasma and urine was measured at different times. Metabolites of TU in these fluids were investigated. Peak levels of radioactivity appeared simultaneously in lymph and plasma (2.5-5 h after administration) while the excretion in urine was highest approximately 2 h after the plasma and lymph peak. The main compounds appearing in the lymph were TU and 5alpha-dihydrotestosterone undecanoate (5alpha-DHTU), but 5beta-DHTU could not be detected. In plasma almost all metabolites were probably conjugated. During the first 24 h approximately 40% of the administered radioactivity was excreted in the urine. The total amount of radioactivity excreted in the urine during the first week was 45-48%. The predominant urinary metabolites were testosterone- and androsterone-glucuronide. The results indicate that TU is metabolized partly in the intestinal wall. The remaining TU and newly-formed 5alpha-DHTU, at least partly, are absorbed via the lymphatic system.

Selective removal of hypersecreting pituitary adenomas

Abstract: The aim of this study of 101 pre- and postoperatively controlled hypersecreting pituitary adenomas (80 acromegalies, 15 Cushing's diseases, 6 Nelson's syndromes) was to establish in what cases a selective adenoma extirpation by the transnasal route is possible and advisable. In primary operations on acromegalics with small and medium size tumours 92% were postoperatively GH normal. Eighty five per cent of these had intact pituitary function. The results with larger tumours were worse (72%). During a control period of 1.5–5.5 years a renewed elevation of GH levels was observed in three cases, all in the first year, but never after clearly selective adenomectomy. These results, and the anterior lobe biopsies, which showed no GH cell hyperplasia, favour selective adenoma extirpation. In contrast to acromegaly, nodular ACTH cell hyperplasia in the anterior lobe was found in most cases of Cushing's disease, and therefore complete hypophysectomy was performed. The cortisol levels became either normal or, in most cases, lower than normal. A selective operation was performed on 6 Nelson tumours. The ACTH values became normal in about 50% of the patients but there was a tendency towards recurrence. Our experiences with Cushing's disease and Nelson's syndrome lead us to recommend total hypophysectomy.

On the diffusion of momentum and mass by internal gravity waves

Abstract: The interaction between short internal gravity waves and a larger-scale mean flow in the ocean is analysed in the Wkbj approximation. The wave field determines the radiation-stress term in the momentum equation of the mean flow and a similar term in the buoyancy equation. The mean flow affects the propagation characteristics of the wave field. This cross-coupling is treated as a small perturbation. When relaxation effects within the wave field are considered, the mean flow induces a modulation of the wave field which is a linear functional of the spatial gradients of the mean current velocity. The effect that this modulation itself has on the mean flow can be reduced to the addition of diffusion terms to the equations for the mass and momentum balance of the mean flow. However, there is no vertical diffusion of mass and other passive properties. The diffusion coefficients depend on the frequency spectrum and the relaxation time of the internal-wave field and can be evaluated analytically. The vertical viscosity coefficient is found to be vv [ape ] 4 x 103cm2/s and exceeds values typically used in models of the general circulation by at least two orders of magnitude.

The aggregation pheromones of bark beetles: Progress and problems

Abstract: Bark beetles (Coleoptera: Scolytidae) are insect pests inhabiting the subcortical tissues of trees. They account for much of the timber losses in coniferous forests throughout the Northern Hemisphere. Destructive outbreaks have been recorded in the past and present alike as soon as windstorms, drought, flood, root competition, or defoliation impair tree health and provide suitable host material for exploding beetle populations. Attacking en masse, aggressive populations overcome their host trees regardless of health or vigor. What appears to be attack by brute force, however, is actually the outcome of an intriguing system of chemical communication which in many respects resembles that of social insects more closely than the sex pheromones of lepidoptera. The elements of scolytid communication are host-produced volatiles as well as insect-produced pheromones; the response is not truly sex-specific, with both male and female beetles aggregating [1]. This ensures the utilization of temporary habitats [2] such as broken limbs or lightning-struck trees, providing an obvious mechanism for survival of endemic populations. But the same mechanism may mark resistant trees for simultaneous mass attack when and where epidemic populations prevail. Consequently, the term \"population aggregating pheromones\" or briefly \"aggregation pheromones\" (Populationslockstoffe) was introduced to emphasize the pheromonal function in host colonization. This is not to overlook the fact that aggregation of both sexes leads to the encounter of a mate. Nevertheless, the target marked by bark-beetle pheromones is the host, in contrast to the sex pheromones, where it is the mate. The fact that bark beetles are attracted to, and aggregate on, suitable host material has been commonly known for centuries and was used empirically in Europe to combat the pest with \"trap trees\". Gmelin [3] described such procedures in his remarkable essay \"Abhandlung fiber die Wurmtrocknis\" as early as 1787. However, Anderson [4] was first to prove the existence of attractants experimentally in 1948 and another decade passed before research investigated this phenomenon systematically [5]. The experimental proof that beetle-produced volatiles are involved in bark-beetle attraction was followed by the first successful identification of three terpene alcohols [6] in 1966. Since then, considerable progress has been made in the identification of aggregation pheromones and related structures, as well as in the biosynthesis of such compounds and the insect's response behavior. Aggregation pheromones are thought to occur throughout the family of Scolytidae with a few possible exceptions [7]; but there are many bark-beetle species which respond most readily to resinous materials exuding from damaged or infested timber as, for example, Blastophagus piniperda [8]. In general, the beetles emerge from a brood tree or overwintering site and disperse in search of new breeding places. Random dispersal and close-range host recognition, which may include olfactory response to host odors (primary attraction), are considered instrumental. Invariably, the beetle initiating gallery construction selects the host. In monogamous bark-beetle species, this is the female; among polygamous beetles, the male. As they enter the bark, pheromones are released usually by defecation, and/or host volatiles are activated. Colonization starts in response to this strong and specific secondary attraction, which increases as more beetles enter the same host and generate more of the attractive principle (Fig. 1). During this stage of attack, the focus of attraction may extend from a part of a tree to the whole, and from several trees into an attractive area in which beetles aggregate for mutual attack of additional hosts. Many Dendroctonus and some Ips spp. are capable of marking new host trees in spite of copious resin flow which prevents the beetles from feeding. Such \"contact pheromones\" are appar-

Kristallstruktur des Kupfer(I)‐tert‐butoxids, [CH3)3 COCu]4

Abstract: Die aus Wasserfreiem CuCl und (CH3)3COLi in THF dargestellte Titelverbindung Kristallisiert triklin (Raumgruppe P1). Die Struktur wurde rontgenographisch bestimmt und bis R = 0.071 verfeinert. Vier Formeleinheiten bilden einen planaren Ring, in dem alternierend vier Kupfer- und vier Sauerstoff-Atome miteinander verbunden sind. Auch im Gaszustand liegen nach dem Massenspektrum tetramere Einheiten vor. Crystal Structure of Copper(I) tert-Butoxide, [CH3)3COCu]4 The title compound, prepared form anhydrous CuCl and (CH3)3COLi in THF, forms triclinic crystals (space group P1). The structure has been determined by X-ray analysis and refined to R = 0.071. Four formula units form a planar ring containing four copper atoms and four oxygen atoms. According to the mass spectrum the compound forms tetrameric units also in the vapour phase.

Chromatid exchanges in ataxia telangiectasia, Bloom syndrome, Werner syndrome, and xeroderrna pigmentosum

Abstract: The frequency of BrdU-induced sister chromatid exchanges (SCE) in cultured lymphocytes from patients with ataxia telangiectasia, Werner syndrome, and xeroderma pigmentosum was normal. The rate was increased in xeroderma pigmentosum following exposure to ultraviolet light and spontaneously raised in the Bloom syndrome. Quadriradial exchanges between homologous chromosomes in Bloom syndrome not only involve sister chromatids but also homologous (non-sister) chromatids. This could result in the formation of recombinant chromosomes and is viewed as a genetically determined form of increased somatic recombination in man. Endoreduplicated metaphases showed 'twin' and 'single' exchanges in a 1:2 ratio. This suggests a comparable frequency of exchanges at both divisions and provides evidence for the polarity of the chromatid subunits and the presence of a single chain of DNA.

Classification of the pathohistology of diseases of the salivary glands - review of 2,600 cases in the Salivary Gland Register.

Abstract: Three major disease groups emerge from a classification of the pathohistology of 2,600 salivary gland preparations in the salivary gland register (from 1965 to 1974): salivary gland tumors (41%), salivary gland inflammations (26%), and sialadenosis (6%). Mucoceles (2%) and salivary gland cysts (1.5%) are seen less often. It is diagnostically important that lymph node changes in the area of the salivary glands (lymphadenitis, lymphomas, etc.) are worked up under suspicion of a primary salivary gland disease. Sialadenosis involves a primary, vegetative neuropathy, which is accompanied by enlargement of acinar cells. Under the heading of chronic sialdenitis, we fine 50% socalled Kuttner tumors of the submandibular gland, 21% chronic relapsing parotitis, 14% chronic inflammations of the minor salivary glands and the sublingual gland, and 12% immune sialadenitis (myoepithelial sialadenitis in Sjogren's syndrome and epitheloid cell sialadenitis in Heerfordts syndrome). A more than average number of immune sialadenitis cases develop into malignant lymphomas (4 cases in the salivary gland register). The 1,067 tumor cases containing of 929 epithelial tumors (87%), 89 mesenchymal tumors (hemangiomas, lymphangiomas, lipomas, neurofibromas, sarcomas) and 49 metastases or periglandular tumors. Epithelial tumors were grouped on the basis of the World Health Organization (WHO) classification. Benign tumors (71.5%) consisted of pleomorphic adenomas (51.5%) and monomorphic adenomas (50%). After the pleomorphic adenomas, cystadenolymphomas (over 10%) represented the most frequent benign salivary gland tumor. On the basis of epithelial and stromal differentiation, pleomorphic adenomas were subdividied into four subtypes (stroma-rich and stroma-poor adenomas). The malignant tumors consisted of acinar cell tumors (2.5%), mucoepidermoid tumors (6%), and carcinomas at various levels of differentiation (adenoid-cystic carcinomas, 6.5%; adenocarcinomas, 2%; squamous cell carcinomas, 2%; carcinomas in pleomorphic adenomas, 4%; miscellaneous carcinomas - salivary duct carcinomas, clear-cell carcinomas, undifferentiated carcinomas, 5.5%). Differences in age and sex distribution, localization, malignity metastases, recidivism, et

Observation of Surface Excitons in Rare-Gas Solids

Abstract: Evidence is obtained for the excitation of surface excitons in solid Ar, Kr, and Xe in optical transmission and reflection experiments using synchrotron radiation. They are located at photon energies ranging from 0.6 eV for Ar to 0.1 eV for Xe below the corresponding bulk excitons excited from the valence bands. Their halfwidths (20-50 MeV) are less than half the values found for the bulk excitons. Some are split by an amount considerably smaller than the spin-orbit splitting of the valence bands.

Isolation of a moderate halophilic ammonia-oxidizing bacterium, Nitrosococcus mobilis nov. sp.

Abstract: An ammonia-oxidizing bacterium was isolated from a sample of brackish water (North Sea, Harbour of Husum). It is a motile large coccus 1.5-1.7 mum in diameter. The extensive cytomembrane system occurring as flattened vesicles in the peripheral region of the cytoplasm and as intrusions into the center of the cytoplasm is to be emphasized as a characteristic mark of identification. The lithoautotrophically growing bacterium turned out to be an obligate halophile. Because of its physiological and morphological properties, we assigned it to the genus Nitrosococcus and propose the name Nitrosococcus mobilis.

Surface Plasmon and Polariton Dispersion at Rough Boundaries

Abstract: The influence of surface roughness on electromagnetic surface modes is investigated theoretically. A frequency or wave vector shift is found and a damping of the modes depending on the autocorrelation of the surface roughness. This could be described by an explicit analytic expression. There is good agreement with experimental results on sinus-odially modulated silver surfaces. Der Einflus von Oberflachenrauhigkeit auf elektromagnetische Oberflachenanregungen wird theoretisch untersucht. Eine von der Autokorrelation der Oberflachenrauhigkeit ab-hangige Wellenvektor- oder Frequenzverschiebung sowie eine Dampfung der Anregungen wird gefunden. Diese Effekte lassen sich durch cinen expliziten analytischen Ausdruck beschreiben. Es besteht gute Ubereinstimmung mit experimentellen Ergebnissen an sinus-formig modulierten Silberoberflachen.

High resolution monochromator for the VUV radiation from the DORIS storage ring.

Abstract: The unique properties of the DORIS storage ring at DESY as a synchrotron radiation source are exploited for high resolution spectroscopy in the vacuum ultraviolet. We describe a new experimental set up with a 3-m normal incidence monochromator for wavelengths between 3000 A and 300 A (4 ≤ ħω ≤ 40 eV) using a vertical dispersion plane. The storage ring provides a light flux intense and stable enough for rapid photoelectrical scanning of the spectra with a resolution of 0.03 A in first order.

( n , 2 n ) Anregungsfunktionen für 54 Fe, 70 Ge, 74 Se, 85 Rb, 8688 Sr, 89 Y, 92 Mo, 204 Hg im Neutronenenergiebereich 13–18 MeV

Abstract: Using the activitation method (n,2n) excitation-functions were measured for54Fe,70Ge,74Se,85Rb,8688Sr,89Y,92Mo, and204Hg in the neutron-energy region 13–18 MeV. The results are checked for consistency by means of a systematic of (n, 2n) cross-sections as a function of the nuclear neutron excess (N-Z)/A. Furthermore the data are compared with results from the statistical nuclear reactions theory which were calculated using optical model absorption cross-sections and the Fermi-gas-model formula for the nuclear level density. In the case of204Hg the influence of preequilibrium nucleon emission was taken into account.

Measurement of Surface Plasmon Dispersion in Aluminum and Indium

Abstract: Energy-loss experiments with 50-keV electrons on thin polycrystalline films of Al and In yielded data for the surface plasmon dispersion up to ${k}_{\ensuremath{\parallel}}=0.47 \mathrm{and} 0.42$ ${\mathrm{\AA{}}}^{\ensuremath{-}1}$, respectively. The wave-vector dependence of the surface plasmon frequency of Al shows a significant increase for ${k}_{\ensuremath{\parallel}}g0.3$ ${\mathrm{\AA{}}}^{\ensuremath{-}1}$, while in the case of In there is only a weak increase for ${k}_{\ensuremath{\parallel}}g0.2$ ${\mathrm{\AA{}}}^{\ensuremath{-}1}$.

Ultrastructural studies on the epithelia of the olfactory organ of cyprinodonts (Teleostei, Cyprinodontoidea).

Abstract: The epithelia of the olfactory organ of two cyprinodontoid fish species were studied both by transmission and scanning electron microscopy. The relatively flat floor of the organ is covered by sensory and nonsensory epithelia. The latter is distributed in the form of bands or ridges separating distinct areas of sensory epithelium. Differences between the olfactory organs of the two species investigated related only to the topography and quantitative distribution of the epithelia. Their ultrastructural features are very similar. The nonsensory stratified squamous epithelium contains numerous goblet cells and surface cells provided with microridges. A hypothetical function of the microridges is discussed. The sensory epithelium consists mainly of basal, supporting, and two types of sensory cells, i.e., ciliated and microvillous receptor cells. The cilia exhibitapredominant 9+0 microtubule pattern. Both epithelia are covered by a mucus layer in which all surface structures seem to be embedded. The possible nature, origin, and movement mechanisms of the mucus are discussed.

An ammonia-oxidizing bacterium, Nitrosovibrio tenuis nov. gen. nov. sp.

Abstract: An ammonia-oxidizing, autotroph growing, slender, curved rod was isolated from the soil of Hawaii. It is well distinguishable from any other nitrifying bacteria thus far described by their morphology. The cells are 1.1–3.0 μm long and 0.3–0.4 μm wide. They are motile by means of 1–4 subpolar to lateral flagella. In contrast to most of the ammonia-oxidizing bacteria the isolated vibrio is void of an extensive cytomembrane system. To categorize this not yet described species we propose to create the new genus Nitrosovibrio and to classify the isolated strain as Nitrosovibrio tenuis.