Beiträge zur geographischen Pathologie von Suriname

Zusammenfassung Bei einer Reihe von S?ugetieren in Suriname fanden sich in der Milz bei der Untersuchung von Tupfpr?paraten intracellul?r und gelegentlich auch extracellul?r gelagerte Gebilde, die von Histoplasma nicht zu unterscheiden waren. In einer Reihe von F?llen liessen sich die Parasiten auf weisse M?use verimpfen und bei diesen gleichfalls in der Milz zurückfinden. Mitt.:W. A. Collier, A. E. Wolff undA. E. G. Zaal, Documenta Med. Geogr. et Trop.4, 92, 1952; 2. Mitt.:W. A. Collier undW. E. F. Winckel, Z. f. Hyg. [im Druck; 3. Mitt.:C. F. A. Bruyning, Documenta Med. Geogr. et Trop.4, 171, 1952; 4. Mitt.:W. A. Collier undD. A. de la Parra, Documenta Med. Geogr. et Trop. im Druck; 5. Mitt.:W. E. F. Winckel, W. A. Collier undA. E. G. Treurniet, Documenta Med. Geogr. et Trop. im Druck.     

Neue Taxa vonTillandsia subgenusDiaphoranthema (Bromeliaceae) aus Bolivien und Argentinien

5 new taxa are described and illustrated; their position within the subgenus is discussed:T. hirta W. Till & L. Hromadnik,T. cotagaitensis L. Hromadnik,T. caliginosa W. Till, andT. gilliesii Baker subsp.polysticha W. Till & L. Hromadnik are members of a group includingT. myosura Grisebach exBaker,T. mandonii E. Morren exMez in DC.,T. retorta Grisebach exBaker em.Grisebach andT. andicola Gillies exBaker. T. brealitoensis L. Hromadnik is related toT. angulosa Mez in DC. but distinct and possibly of hybrid origin.

     

Untersuchungen über die Funktion des Zentralnervensystems und insbesondere des Gehirnes bei der Fortbewegung und der Lauterzeugung der Grillen

Ohne ZusammenfassungHerrn Prof. Dr. W. R. Hess in Verehrung und Dankbarkeit gewidmet.Der Deutschen Forschungsgemeinschaft danke ich herzlich für die Förderung dieser Arbeit. Mein Dank gilt ferner den Herren Prof. Dr. O. A. M. Wyss und Dr. R. J. H. Oberholzer, Physiologisches Institut der Universität Zürich, und Herrn Dr. D. Burkhardt, Zoologisches Institut der Universität München, für Beratung in methodischen Fragen.     

Taxonomic notes on<Emphasis Type="Italic">Linaria</Emphasis> mill. (<Emphasis Type="Italic">Scrophulariaceae</Emphasis>) for Flora Iberica

Taxonomic considerations and nomenclatural adjustments as a part of a revision ofLinaria Mill. undertaken within the “Flora iberica” project are presented. Data on morphology, seed coat surface, chorology, ecology, synonymy and variability of 11 accepted taxa are reported. The following new combinations are proposed:Linaria aeruginea subsp. cardonica (Font Quer)L. Sáez etM. Sainz,Linaria depauperata subsp.ilergabona (M.B. Crespo etV.J. Arán)L. Sáez, andLinaria saturejoides subsp.angustealata (Willmott)L. Sáez etM.B. Crespo.     

The organization of the substantia gelatinosa rolandi in the cat lumbosacral spinal cord

Summary The organization of the substantia gelatinosa and adjacent lamina III in cat lumbo-sacral spinal cord has been studied by light and electron microscopical techniques in normal cord and following dorsal root section.The substantia gelatinosa (lamina II of Rexed) is characterized by bundles of small, non-myelinated axons, principally oriented longitudinally. The substantia gelatinosa cells are small, spindle shaped, with a cytoplasm generally devoid of Nissl substance. There are extensive axo-dendritic and axo-axonal contacts within the substantia gelatinosa and less frequent axo-somatic contacts.Larger marginal cells oriented horizontally on the surface of the substantia gelatinosa and containing Nissl substance are also seen.Lamina III is somewhat similar to the substantia gelatinosa, but lacks the complex bundles of non-myelinated axons.Following dorsal root section, heavy degeneration is seen by light and electron microscopy in lamina III, but is rarely seen in the substantia gelatinosa. It is concluded that the substantia gelatinosa and lamina III are distinct anatomically and therefore may differ functionally.The possible physiological role of the substantia gelatinosa is discussed.This work was supported by a Special Fellowship 2F11 NB 1140 02 NSRB from the National Institute of Neurological Diseases and Blindness, United States Public Health Service.The author is indebted to Dr. E. G.Gray for his excellent advice. I thank Dr. R. W. Guillery, Dr. L. E. Westeum and Dr. B. G. Cragg for their assistance, and Prof. J. Z. Young, F. R. S. for his kind suggestions. I also wish to thank Mr. S. Waterman for the photography.     

Über ein weiteres Versetzungsexperiment zur Analyse des Zeitsinnes und der Sonnenorientierung der Honigbiene

Ohne ZusammenfassungMit Unterstützung der Deutschen Forschungsgemeinschaft.Für wertvolle Mitarbeit bei der Durchführung des Versuches danke ich ganz besonders den Herren Dr. Kahl Daumer (München) und grad. stud. Bill Hamilton (Berkeley). Außerdem gilt mein Dank den Herren Prof. Dr. K. v. Frisch (der für das Experiment Mittel aus einer Bewilligung der Rockefeller Foundation zur Verfügung stellte), Prof. Dr. J. E. Eckert, Prof. Dr. H. H. Laidlaw (beide Davis, Kal.), Dr. W. Jahn (München), Prof. Dr. P. Marler (Berkeley), Prof. Dr. T. C. Schneirla (New York) und H. D. Wells (Riverhead, L. I.). Schließlich danke ich der Fa. Siemens und Halske, die mir einen Teil der apparativen Ausrüstung kostenlos überlassen hat.     

Pollen morphology ofSonchus and related genera,and a general discussion

The pollen morphology of the taxa belonging to the generaAetheorhiza Cass.,Launaea Cass.,Reichardia Roth andSonchus L. in the Iberian Peninsula has been studied with light and electron microscopy. The pollen is 3(-4)-zonocolporate and echinolophate (without polar lacunae, but in general with prelacunae), with equatorial ridges and 15–20 lacunae: 3–4 poral, 6–8 abporal and 6–8 paraporal. Small to medium size, P × E = 19–36 × 23–42 µm; sometimes two different sizes have been found. Exine 3–9 µm thick and ornamentation microreticulate and echinate. The results clearly show the relationships between genera. Moreno-Socías, E., Mejías, J. A., Díez, M. J., 1994: Morfología polínica deLactuceae (Asteraceae) en la Península Ibérica, I.Lactuca y géneros relacionados. — Acta Bot. Malacitana.19: 103–113.     

Molecular domain structure of porcine vinculin and metavinculin

Summary Metavinculin is a higher molecular weight variant of vinculin expressed only in cardiac and smooth muscle. Using microsequencing methods on the intact molecules and their proteolytic subfragments we have been able to map the common and different parts of these closely related proteins. Both vinculin and metavinculin, from mammals and birds exhibit a relatively protease resistant 90 kD core fragment. N-terminal sequencing analysis of the avian and mammalian core fragments as well as of major core subfragments obtained by extended proteolysis placed the core domain at the N-terminus of the intact molecules and revealed identity between metavinculin and vinculin as well as between species. Limited chymotryptic digestion of porcine vinculin and metavinculin yielded a common 16 kD fragment which could be placed at the C-terminus of the cDNA sequence derived from chick fibroblast vinculin (G. J.Price, P.Jones, M. D.Davison, R.Bendori, S.Griffiths, B.Patel, B.Geiger and D. R.Critchley 1988, in press). From additional sequence data the metavinculin specific fragment could be placed at the metavinculin C-terminus. Using a polyclonal antibody specific for porcine metavinculin a peptide unique to metavinculin could be identified. Direct sequencing of this, as well as of related, overlapping fragments, purified by reversed phase HPLC revealed a 68 amino acid insert in procine metavinculin, between the core fragment and the C-terminal piece, common to vinculin and metavinculin. The domain organizazions of vinculin and metavinculin and their possible functional implications are discussed.Abbreviations SDS sodium dodecyl sulfate - EDTA ethylendinitrilotetra acetic acid - HPLC high pressure liquid chromatography     

Comparative immunochemical studies with antisera to sheep prolactin and bovine growth hormone on anterior pituitaries of ox,sheep, rats and mice

Summary Rabbit antisera to sheep prolactin and bovine growth hormone were used in the indirect fluorescent antibody technique on cryostat sections of anterior pituitaries of sheep, ox, rats and mice. It is demonstrated that in sheep and ox prolactin and growth hormone are manufactured by different acidophilic pituitary cells. Though the antisera do not precipitate the analogous hormones of rats and mice in gel diffusion tests, evidence is given for the specificity of the cross-reaction of the antisera with the analogous murine hormones in situ as found with the fluorescent antibody technique.We are grateful to Dr. J. D. H. Homan of Organon, Oss (The Netherlands) for the supply of bovine growth hormone and for kindly giving us the information concerning this preparation.We should like to thank Dr. F. J. A. Prop for the prolactin assays, Dr. H. G. Kwa for providing the mouse pituitary tumours and Dr. L. M. Boot for the mouse pituitary isograft in the kidney, Mrs. J. J. Geiger-Koedijk for the conventional staining of pituitary sections, and Mr. J. van der Kamp for the photography.     

Statistical Analysis of Environmental Space-Time Processes edited by N. D. Le and J. V. Zidek

Statistical Analysis of Environmental Space‐Time Processes (N. D. Le and J. V. Zidek) Jon Wakefield Computer‐Intensive Methods of Data Analysis in Biology (D. A. Roff) A. W. Kemp Randomization, Bootstrap, and Monte Carlo Methods in Biology (3rd Edition) (B. F. J. Manly) A. W. Kemp Applied Mixed Models in Medicine, 2nd edition (H. Brown and R. Prescott) Matthew J. Gurka Stochastic Modeling for Systems Biology (D. J. Wilkinson) Olaf Wolkenhauer Knowledge Discovery in Proteomics (I. Jurisica and D. Wigle) Zhen Zhang Computational Genome Analysis: An Introduction (R. C. Deonier, S. Tavaré, and M. S. Waterman) Marc Suling Stochastic Orders (M. Shaked and J. G. Shantikumar) Subhash Kochar Brief Reports by the Editor Measurement Error in Nonlinear Models: A Modern Perspective, 2nd edition (R. J. Carroll, D. Ruppert, L. A. Stefansky, and C. M. Crainiceanu) Basic Statistics and Pharmaceutical Statistical Applications, 2nd edition (J. E. De Muth) A Handbook of Statistical Analyses Using Stata, 4th edition (S. Rabe‐Hesketh and B. S. Everitt) Introduction to Randomized Controlled Clinical Trials, 2nd edition (J. N. S. Matthews) Survival and Event History Analysis (P. K. Andersen and N. Keiding, editors) A Pocket Guide to Epidemiology (D. G. Kleinbaum, K. M. Sullivan, and N. D. Barker)     

On lipid droplets in renal interstitial cells

Summary By examining Epon sections of the renal papilla, it is demonstrated that a brief period of salt repletion in salt-depleted rats induces a considerable increase in the number of lipid droplets in the renal interstitial cells. It is supposed that this difference indicates that the lipid droplets contain substances which are physiologically important for the kidneys. Possibly, these substances are prostaglandins, which have been demonstrated previously by other authors in extracts from the renal medulla.This work was supported by a grant from the Danish State Research Foundation.The author wishes to acknowledge the support and inspiration given by E. Bojesen, M.D., and P. Leyssac, M.D., the Institute of Experimental Medicine.     

Plasmabau und Determination bei dem Ei von Paracentrotus lividus Lk

Ohne ZusammenfassungEs ist mir eine angenehme Pflicht, den Herren bei der Zoologischen Station in Neapel, den Professoren R.Dohrn, M.Fedele, E.Sereni, J.Gross und S.Ranzi sowie den Herren Dr. J.Richard und M.Oxner, Musée océanograph. in Monaco, für erwiesenes Wohlwollen meinen ergebensten Dank zu sagen. Herr K.Vrieslander hat einige der Aquarelle ausgeführt, wofür ich ihm danke.Die Reisen und die Anschaffung der nötigen Apparate wurde durch eine Zuwendung aus der Stiftung, Th. und J.Anderssons minne möglich gemacht.     

Veronica allahuekberensis (Scrophulariaceae), eine neue Art aus der Türkei

Veronica allahuekberensis A. Öztürk, spec. nova, probably endemic to the Allahuekber mountain in N.E. Anatolia, belongs toV. orientalis group of sectionVeronica and resemblesV. cuneifolia D. Don subsp.cuneifolia, endemic to S.W. Anatolia.

     

TAXONOMIC, FAUNISTIC AND MISCELLANEOUS

Al -Dabagh , M. A. 1964. The incidence of blood parasites in wild and domestic birds of Columbus, Ohio. Amadon , D. 1966. The super:pecies concept. Bergstrand , J. L. & Klimstra , W. D. 1964. Ectoparasites of the Bobwhite Quail in Southern Illinois. Bernis , F. 1963. La invernada y migración de nuestros Ansares. Brinck , P., Svedmyr , A. & Zeipel , G. von . 1965. Migrating birds at Ottenby, Sweden, as carriers of ticks and possible transmitters of tick-borne encephalitis virus. Carrick , R. & Ingham , S. E. 1967. Antarctic sea-birds as subjects for ecological research. Carriker , M. A. 1966. New species and records of Mallophaga (Insectnt) from Neotropical owls (Strigiformes). Davis , P. 1963. Recent developments at Fair Isle. Diamond , A. W., Douthwaite , R. J. & Indge , W. J. E. 1965. Notes on the birds of Berneray, Mingulay and Pabbay. Dott , H. E. M. 1967. Numbers of Great Skuas and other seabirds of Hermaness, Unst. Evans , P. R. & Flower , W. U. 1967. The birds of the Small Isles. Grierson , J. 1962. A check-list of the birds of Tentsmuir, Fife. Gysels , H. 1964. Bijdrage tot de Systematiek van de Vogels, aan de hand van de elektroforese in agar van de oplosbare lens- en spierproteinen. Harris , M. P. 1964. Ring loss and wear of rings on marked Manx Shearwaters. Hytönen , 0. 1965. Fruhjahrsbeobachtungen uber die Vogelwelt der siidlichen Toskana. Jackson , E. E. 1966. The birds of Foula. Johnsgard , P. A. 1967. Sympatry changes and hybridisation incidence in Mallards and Black Ducks. Johnson , N. K. 1966. Bill size and the question of competition in allopatric and sympatric populations of Dusky and Gray Flycatchers. MOEPCKE, M. 1965. Zur Kenntnis einiger Furnariiden (Aves) der Küste und des westlichen Andenabhanges Perus. Lanyon , W. E. 1966. Hybridization in Meadowlarks. Maynard Smith , J. 1966. Sympatric speciation. Mayr , E. 1965. What is a fauna? Mc Clure , H. E. 1966. An Asian bird-bander's manual. Medway , Lord . 1966. Field characters as a guide to the specific relations of Swiftlets. Novobytov , A. 1968. [Bird strikes on aircraft in the Soviet Union.] Yuni Tekhnik [The Young Technician] Packard , G. C. 1967. House Sparrows: Evolution of populations from the Great Plains and Colorado Rockies. Pearson , J. M. & Scott , P. 1965. “Save the Flamingo”: was it a good idea? Pennie , I. D. 1962. A century of bird-watching in Sutherland. Pennie , I. D. 1966. Ornithology in Scotland: a historical review. Penny , R. L. & Sladen , W. J. L. 1966. The use of Teflon for banding Penguins. Prigogine , A. 1967. La faune ornithologique de l'ile Idjwi. Sandeman , P. W. 1965. Attempted reintroduction of White-tailed Eagle to Scotland. Sessions , P. H. B. 1966. Notes on the birds of Lengetia Farm, Mau Narok. Short , L. L. 1965. Variation in West Indian Flickers (Aves, Cokzptes). Sick , H. 1963. Hybridisation in certain Brazilian Fringillidae (Sporophila and Oryzoborus). Siaden , W. J. L. & Friedmann , H. 1961. Antarctic Ornithology. Sladen , W. J. L. 1965. Ornithological research in Antarctica. Slater , R. L. 1967. Helminths of the robin, Turdus nzigratorius Ridgway, from Northern Colorado. Smith , V. W. 1966. Birds seen on a trans-Saharan overland crossing in spring 1966. Strange , I. J. 1965. Beauchene Island. Voous , K. H. 1967. Man and predators. Vos , A. De . 1964. Range changes of birds in the Great Lakes region. Waters , W. E. 1962. The birds of St. Kilda—winter 1961–62. Weins , J. A. 1966. On group selection and Wynne-Edwards' hypothesis.     

REVIEWS

Books reviewed in this article:
Plant Anatomy: Experiment and Interpretation , Part II, Organs. By E lizabeth G. C utter .
Genetics. By D. J. C ove .
The Structure and Life of Bryophytes. By E. V. W atson .
Underwater Science. Ed. by J. D. W oods and J. J. L ythgoe .
8ème Symposium Européen sur les Maladies à Virus des Arbres Fruitiers.
Evolution and Plants of the Past. By H. P. B anks .
Project Aqua. A Source Book of Inland Waters Proposed for Conservation. IBP Handbook No. 21. By H. L uther and J. R zóska .
Variation and Adaptation in Plant Species. By D. A. J ones and D. A. W ilkins .
Flora of Lesotho (Basutoland). By A my J acot G uillarmod .
Introduction to Biogeography. By B rian S eddon .
Trees: Structure and Function. By M. H. Z immerman and C. L. B rown ;
Flora of New Zealand , Volume II. By L. B. M oore and E. E dgar .     

Evolutionary potential of (beta/alpha)8-barrels: stepwise evolution of a "new" reaction in the enolase superfamily

The molecular details of the processes involved in divergent evolution of "new" enzymatic functions are ill-defined. Likely starting points are either a progenitor promiscuous for the new reaction or a progenitor capable of catalyzing the new reaction following a single substitution that results from a single base change. However, the molecular (sequence) pathway by which the selective advantage provided by this protein can be improved and ultimately optimized is unclear. In the mechanistically diverse enolase superfamily, we discovered that a monofunctional progenitor could acquire the ability to catalyze a "new" reaction by a single base change: the D297G mutant of the monofunctional l-Ala-d/l-Glu epimerase (AEE) from Escherichia coli catalyzed a low level of the o-succinylbenzoate synthase (OSBS) reaction as well as a reduced level of the AEE reaction [Schmidt, D. M. Z., Mundorff, E. C., Dojka, M., Bermudez, E., Ness, J. E., Govindarajan, S., Babbitt, P. C., Minshull, J., and Gerlt, J. A. (2003) Biochemistry 42, 8387-8393]. We then discovered that the selective advantage and OSBS activity of the D297G mutant are both enhanced by the I19F substitution [Vick, J. E., Schmidt, D. M. Z., and Gerlt, J. A. (2005) Biochemistry 44, 11722-11729]. Both the D297G and I19F substitutions are positioned to alter the substrate specificity so that the substrate for the OSBS reaction is more productively positioned vis a vis the active site catalytic groups. We now report that both the selective advantage and OSBS activity of the D297G/I19F double mutant are enhanced by the R24C (one base change from the wild type Arg codon), R24W (two base changes from the wild type Arg codon and one base change from the R24C codon), and L277W (one base change from the wild type Leu codon) substitutions. The effects of the R24C and L277W mutants are "additive" in the D297G/I19F/R24C/L277W mutant. The greatest selective advantage and OSBS activity are associated with the D297G/I19F/R24W mutant. These "new" substitutions that enhance both the selective advantage and kinetic constants are positioned in the active site where they can alter the specificity, highlighting that the evolution of the "new" OSBS function can be accomplished by changes in substrate specificity.     

REVIEWS

Book reviewed in this article:
Plant Cells . By F. A. L. C lowes and B. E. J uniper .
The History of British Vegetation . By W inifred P ennington . Modern Biology: General Editor J. E. W ebb .
Flora Europaea , Vol. II. Rosaceae to Umbelliferae . Ed. by T. G. T utin , V. H. H eywood , N. A. B urges , D. M. M oore , D. H. V alentine , S. M. W alters and D. A. W ebb .
Desert Wild Flowers . By E dmund J aeger .
British Mosses and Liverworts . By E. V. W atson .
Anatomy of the Monocotyledons , Vol. III. Commelinales—Zingiberales . By P. B. T omlinson . General Editor C. R. M etcalfe .
Biological Science—The Web of Life . Supervising Editor, D. M organ .
Plant Chimeras . By W. N eilson -J ones .
The Potatoes of Argentine, Brazil, Paraguay and Uruguay, a Biosystematic Study . By J. G. H awkes and J. P. H jerting .
Towards an Understanding of the Mechanism of Heredity . By H. L. K. W hitehouse .
Viruses in Plant Hosts; Form, Distribution and Pathologic Effects . By K atherine E sau .
An Introduction to Industrial Mycology . By G eorge S mith .     

Altered expression of Autism-associated genes in the brain of Fragile X mouse model

Autism is a severe neurodevelopmental disorder, which typically emerges in early childhood. Most cases of autism have not been linked to mutations in a specific gene, and the etioloty of the disorder remains to be established [S.S. Moy, J.J. Nadler, T.R. Magnuson, J.N. Crawley, Mouse models of autism spectrum disorders: the challenge for behavioral genetics, Am. J. Med. Genet. 142 (2006) 40-51]. Fragile X syndrome is caused by mutation in the FMR1 gene and is characterized by mental retardation, physical abnormalities, and, in most case, autistic-like behavior [R.J. Hagerman, A.W. Jackson, A. Levitas, B. Rimland, M. Braden, An analysis of autism in fifty males with the Fragile X syndrome, Am. J. Med. Genet. 23 (1986) 359-374, C.E. Bakker, C. Verheij, R. Willemsen, R. van der Helm, F. Oerlemans, M. Vermeij, A. Bygrave, A.T. Hoogeveen, B.A. Oostra, E. Reyniers, K. De Boulle, R. D’Hooge, P. Cras, D. van Velzen, G. Nagels, J.J. Marti, P. De Deyn, J.K. Darby, P.J. Willems, Fmr1 knockout mice: a model to study Fragile X mental retardation, Cell 78 (1994) 23-33]. The FMR1 knockout (KO) mouse is one of the best characterized animal models for human disorders associated with autism [S.S. Moy, J.J. Nadler, T.R. Magnuson, J.N. Crawley, Mouse models of autism spectrum disorders: the challenge for behavioral genetics, Am. J. Med. Genet. 142 (2006) 40-51]. We have used real-time PCR to investigate changes in expression levels of three genes: WNT2, MECP2, and FMR1 in different brain regions of Fagile X mice and litter mate controls. We found major changes in the expression pattern for the three genes examined. FMR1, MECP2, and WNT2 expression were drastically down regulated in the Fragile X mouse brain.     

Purification and properties of D-gluconate dehydratase fromAchromobacter

d-Gluconate dehydratase fromAchromobacter, grown ond-gluconate, was purified 100-fold by a procedure involving ammonium sulfate fractionation and preparative acrylamide gel electrophoresis. The purified enzyme appeared to be homogeneous by disc gel electrophoresis. It is an inducible enzyme with an optimal activity in the pH region 8.4–8.8, a Km value of 2.08 × 10^–2 m ford-gluconate and a molecular weight of 270,000 ± 25,000. Only C₅ and C₆ aldonic acids possessing al-threo configuration at C₂ and C₃ are dehydrated. The dehydration products ofd-gluconate,d-xylonate,d-galactonate,d-fuconate andl-arabonate were identified as 2-keto-3-deoxy compounds by specific colour reactions and thin layer chromatography. Onemm Mg^{+ +} is a powerful activator, 0.1 mm Mn^{+ +} activates poorly and EDTA inhibits. Glutatione, dithiothreitol and mercaptoethanol had no effect, althoughp-chloromercuribenzoate (0.01 mm) decreased enzyme activity.We wish to thank Mr D. Dewettinck for skilful technical assistance. The senior author (J.D.L.) is indebted to the Fonds voor Kollektief en Fundamenteel Onderzoek (Belgium) for research and personnel grants. J.K.-M. is indebted to the Belgian government for a travel and study grant.     

Die Mittelung von Reaktionspotentialen

The evidence of averaged evoked potentials has been proved. The resulting possibilities for calculation and reduction of the standard deviation are discussed with special regard to computer application. Examples of acoustic evoked responses from the cortex of the cat and the scalp of man demonstrate the suggested processing of EEG data.

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Dissertation Erlangen 1968.

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Zu danken habe ich Herrn Professor Dr. W. D. Keidel für viele Anregungen und für die Schaffung ausgezeichneter Arbeitsbedingungen, Herrn Professor Dr. E. Mollwo für das gezeigte Interesse und für wertvolle Ratschläge bezüglich der Darstellung der Ergebnisse, Herrn Dr. E. David und Herrn Dipl.-Phys. S. Kallert für viele fördernde Diskussionen und für eine über den kollegialen Rahmen hinausgehende interdisziplinäre Zusammenarbeit, Herrn K. Burian für sorgfältigste Ausführung der photographischen Arbeiten und Frau M. Fumy für qualifizierte technische Unterstützung. — Die Arbeit wurde durch die Deutsche Forschungsgemeinschaft apparativ entscheidend gefördert.