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| Registros recuperados: 192 | |
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| Bruyn, Willemina M. de. |
| Previous investigations (see Literature) by means of tissue culture methods have shown that the malignant lymphoblasts of mouse lymphosarcoma MB (T 86157) can be cultivated indefinitely when in the presence of actively growing mesenchyme cells. Under the cultural conditions provided, which included the use of low concentrations of embryo extract, a symbiotic relationship appeared to be established between the malignant lymphoblasts and the normal mesenchyme. It was also shown that media rich in embryo extract allowed only fibroblasts to proliferate. In the present article we wish to report some results of observations on the cultivation of the malignant lymphoblasts without the supporting mesenchyme. |
| Tipo: Article / Letter to the editor |
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| Ano: 1949 |
URL: http://www.repository.naturalis.nl/record/504405 |
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| Voous, K.H.; Marle, J.G. van. |
| Recently RIPLEY (1941) has prepared a systematic revision of the Indo-Australian members of the genus Coracina (Cuckoo-Shrike), which for a considerable time had been in a state of great confusion. RYPLEY’s new arrangement represents a noteworthy step in the appreciation of the systematics of this difficult genus. Since only taxonomy and representative distribution have been taken into account by RIPLEY, resulting in the arrangement of 12 species into 3 superspecies and 7 isolated forms, certain problems still remain unsettled. It is the purpose of this paper to deal with some of these problems and to propose an arrangement of the Indo-Australian forms of Coracina not only in accordance with their taxonomy, but also with the history of their distribution.... |
| Tipo: Article / Letter to the editor |
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| Ano: 1949 |
URL: http://www.repository.naturalis.nl/record/504280 |
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| Vorstman, A.G.. |
| Tijdens het directoraat van Prof. Dr. J. E. W. IHLE is mij op het Zoölogisch Laboratorium steeds vrijheid gelaten om bij de studenten belangstelling te wekken voor hydrobiologisch onderzoek. Hoewel de Hoogleraar IHLE dit onderdeel der biologie zelf niet beoefende, verleende hij hiervoor met grote bereidwilligheid alle materiële steun, waartoe de bescheiden middelen van het laboratorium hem in staat stelden. Wij beschikken thans dan ook over een kern van literatuur op hydrobiologisch gebied, waartoe niet weinig heeft bijgedragen de aankoop van de gehele separatencollectie van wijlen Dr. H. C. REDEKE, waarvoor de steun van de Vereeniging „Het Natuur- en Geneeskundig Congres” werd verkregen. Onder auspiciën van het Zoölogisch Laboratorium werden in de jaren... |
| Tipo: Article / Letter to the editor |
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| Ano: 1949 |
URL: http://www.repository.naturalis.nl/record/504641 |
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| Engel, H.. |
| 1 specimen, Inhaca Island, Delagoa Bay near Lorenço Marques, coll. Prof. Dr. C. J. van der Horst. This animal closely resembles Ophioteresis elegans Bell, 1892 (Proc. Zool. Soc. London, p. 178, Pl. XI, Fig. 1—5) and Ophiothela tigris (Lyman, 1871, III. Catal. Mus. Comp. Zool. VI, p. 10 in Mem. Mus. Comp. Zool. Harvard Coll. II), both described more in detail by MORTENSEN, 1913 (Mindeskrift for Japetus Steenstrup, X, København). See also SOLLAS, 1914, in Phil. Trans. R. Soc. London, ser. B, vol. 204, Pl. 9, Fig. 2. It differs, however, in having the skin of the upper side of the arms covered by rough thorny nodules, while the smooth grains on the upper side of the disc occur here only between the large radial shields. |
| Tipo: Article / Letter to the editor |
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| Ano: 1949 |
URL: http://www.repository.naturalis.nl/record/504334 |
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| Vonk, H.J.. |
| Steeds meer wordt in de biologische en medische wetenschappen gebruik gemaakt van isotopen als hulpmiddel bij het wetenschappelijk onderzoek. In het hier volgend artikel wordt getracht, aan de hand van enige voorbeelden, een inzicht te geven in hetgeen met deze methode te bereiken is in de dierphysiologie. Beginnen wij met een definitie te geven van het begrip isotoop. De chemische eigenschappen van een element worden bepaald door het aantal positieve ladingseenheden van de kern (overeenkomend met het aantal electronen dat om de kern wentelt). Dit aantal ladingseenheden is gelijk aan het aantal deeltjes met lading 1 en massa 1 (protonen), dat in de kern aanwezig is. De eenvoudigste kern, die van waterstof, bestaat uit slechts één proton. Behalve protonen... |
| Tipo: Article / Letter to the editor |
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| Ano: 1949 |
URL: http://www.repository.naturalis.nl/record/504511 |
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| Sitter, L.U. de; Sitter-Koomans, C.M. de. |
| In the Bergamasc Alps we have observed one major unconformity between the Basement rock and the overlying Permian. The total absence of any recognisable Palaeozoic sedimentary rocks accentuates this unconformity, and moreover this enormous hiatus makes the dating of any Palaeozoic event impossible. However, by comparison with the Central Alps and Kärnten, we learned that the Asturian orogenitic phase precedes the deposition of the first volcanic sediments. In analogy with the Aar and Gotthard masses we presumed the intrusion of the less metamorphic ortho rocks of the Basement, the granodiorite and the gneiss chiaro, to be of Upper Carboniferous age. The close resemblance of the chemical composition and differentiation of the Permian volcanic rocks and the... |
| Tipo: Article / Letter to the editor |
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| Ano: 1949 |
URL: http://www.repository.naturalis.nl/record/505987 |
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| Bierens de Haan, J.A.. |
| For certain reasons I wished to train a young chimpanzee to choose from two similar boxes the one characterised by the ticking of a metronome inside it. My subject was a young male chimpanzee (Pan leucoprymnus Lesson), approximately three years old, Tommy by name. He was a good-natured chap, quite tame, and already for some years in captivity. When we knew each other a little better, he would welcome me every morning with a hearty “uhuh”, as soon as he heard my steps, and after the experiments of the day we would take leave by shaking hands as old friends. Tommy was rather lazy and not so playful as most young chimpanzees, but this quality made working with him easier and more regular. With a few exceptions it did not give much trouble to make 50—60 trials... |
| Tipo: Article / Letter to the editor |
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| Ano: 1949 |
URL: http://www.repository.naturalis.nl/record/504669 |
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| Delsman, H.C.. |
| After having collected the plankton samples in the Java Sea on which I have reported in Treubia XVII, 1939, I thought it desirable to gather similar samples from a more oceanic area of the East Indian seas, in order to be able to make a comparison between the two collections and to try to find out the characteristic differences between the two regions. It seemed to me interesting to choose in the first place Sunda Strait for this purpose, as it connects the shallow Java Sea with the deep Indian Ocean and, therefore, might offer all degrees of transition from the plankton of the former to that of the latter. The next year, then, in 1933, I made a cruise in Sunda Strait in the months of April-May, the transition months between the (wet) west monsoon and the... |
| Tipo: Article / Letter to the editor |
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| Ano: 1949 |
URL: http://www.repository.naturalis.nl/record/504054 |
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| Portielje, A.F.J.. |
| As far as I know, little has been published and no thorough investigation has ever been made of the courting, mating, nesting, brooding and rearing of the Condor, though in some of the zoological gardens this largest and in many respects peculiar bird of prey sometimes most succesfully bred. In 1939, 1940 and 1942, a pair of Condors hatched in the gardens of the Royal Zoological Society “Natura Artis Magistra” in Amsterdam. They sat each time on one egg for 58 days alternately. In this way they brought up three young ones, the third of which, however, unfortunately lived only 12 days. It died 9 days after its mother’s death. Besides my preliminary notes in former years, annotations and protocolls were collected in 343 daily reports on this couple and its... |
| Tipo: Article / Letter to the editor |
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| Ano: 1949 |
URL: http://www.repository.naturalis.nl/record/503884 |
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| Raven, Chr.P.. |
| 1. The maturation divisions of the egg of Limnaea stagnalis L. have been studied. 2. The haploid number of chromosomes is 18. 3. At the telophase of the first maturation division, the central group of dyads reaches the surface of the inner central body of the first maturation amphiaster. 4. This central body directly transforms into the second maturation spindle. 5. The aster surrounding this central body gradually disappears. New astral radiations are formed in the cytoplasm near the outer end of the newly formed second maturation spindle. 6. The spermaster, which appears during the telophase of the first maturation division, fuses secondarily with the inner end of the second maturation spindle and forms the inner aster of the second maturation... |
| Tipo: Article / Letter to the editor |
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| Ano: 1949 |
URL: http://www.repository.naturalis.nl/record/504345 |
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| NN. |
| Baas Becking, L.G.M.: Notes on jungle trees I (Chron. Nat. 104, 1948, 271-277). Calculation of the age of the stand in the mountain forest reserve Tjibodas on Mt Gedeh, W. Java, by means of new measurements on the trees numbered by S.H. Koorders in 1890. By means of the losses (0.77% annually) the average life span of a tree is estimated at ca 130 years. Backer, C.A. c.s.: Beknopte Flora van Java (nooduitgave) afl. VII. Fam. XCLVIII-CLXXII. Rijksherbarium, Leiden. Sept. 1948. This instalment of the mimeographed emergency edition (in Dutch) contains the treatments of Meliaceae, Sapindaceae, Aceraceae, Sabiaceae, Staphyleaceae, Anacardiaceae, Connaraceae, Juglandaceae, Cornaceae, Alangiaceae, Nyssaceae, Araliaceae, Umbelliferae, Clethraceae, Ericaceae,... |
| Tipo: Article / Letter to the editor |
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| Ano: 1949 |
URL: http://www.repository.naturalis.nl/record/532951 |
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| Oye, Paul van. |
| Quelques années avant la guerre mon collègue le Professeur R. KOLKWITZ de Berlin m’a confié une série de 20 échantillons de matériel qu’il avait récolté à Java en octobre 1931. Je remercie ici bien vivement M. KOLKWITZ pour l’envoi de ces échantillons. La collection a déjà fait l’objet d’un travail de R. KOLKWITZ lui-même en collaboration avec W. KRIEGER. Le professeur KOLKWITZ en me confiant ce matériel m’a fait savoir que pour les indications des lieux et les données écologiques les numéros des échantillons correspondaient avec ceux de ce travail. Le petite collection d’échantillons s’est montrée d’une très grande importance pour notre connaissance des Rhizopodes de Java, dont les données sont encore très fragmentaires. |
| Tipo: Article / Letter to the editor |
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| Ano: 1949 |
URL: http://www.repository.naturalis.nl/record/504380 |
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| Barendrecht, G.. |
| Wanneer iemand een periode van zijn leven afgesloten ziet, tracht hij voor zichzelf een balans op te maken van de vervlogen jaren. Wanneer hij in die tijd een openbare functie heeft bekleed, zullen ook anderen dat doen. Voor die anderen is dat een moeilijke opgave, want is het schrijven van een necrologie al een moeilijke zaak, het schrijven over een nog levend man van karakter, die het zeker niet zal waarderen in zijn gezicht geprezen te worden, is nog oneindig moeilijker. Toch maak ik dankbaar van de gelegenheid gebruik om de figuur van den scheidenden professor IHLE tenminste voor één maal voor het voetlicht te halen, dat hij altijd zo graag heeft willen ontlopen. Mijn eerste herinnering dateert van begin October 1925, toen de nieuwbenoemde professor,... |
| Tipo: Article / Letter to the editor |
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| Ano: 1949 |
URL: http://www.repository.naturalis.nl/record/504659 |
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| Boeseman, M.. |
| When, in the fall of 1947, my predecessor, Dr. F. P. Koumans, suddenly withdrew from ichthyological research, some of the fossil fish-remains from Trinil, collected and partly examined by Prof. Dr. E. Dubois (1907; 1908), still remained to be investigated or re-examined. I gladly accepted the opportunity to complete the research on this interesting material. A considerable part of these fossil remains, labelled by Dr. Koumans (but not mentioned in his paper, 1948, p. 80) as "16 fragments of skullbones", which "probably belong to Ophicephalus spec." (no. 11640), still proved to be in a sufficient state of preservation to permit an accurate identification of the bones these fragments must represent, as well as of the kind of fish to which the greater part... |
| Tipo: Article / Letter to the editor |
Palavras-chave: 38.22; 42.81. |
| Ano: 1949 |
URL: http://www.repository.naturalis.nl/record/319431 |
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| Lieftinck, M.A.. |
| Weinig onderzoekingen hebben in zo wijde kring bekendheid verworven als die van onze landgenoot JAN SWAMMERDAM, die in zijn ,Ephemeri vita’ (1675) en later in de ,Bybel der Natuur of Historie der insekten’ (1737) de ontwikkelingsgeschiedenis beschreef van het beroemd geworden Oever-aas, Palingenia longicauda (Oliv.), de grootste palaearctische Ephemeride. Dit allermerkwaardigst insect, dat — het zij terloops opgemerkt — reeds in 1634 door de Amsterdamse medicus AUGERIUS CLUTIUS was beschreven en afgebeeld ¹), moet destijds in ons land alom de aandacht hebben getrokken wegens zijn massaal optreden gedurende een aantal warme dagen omstreeks het midden van de maand Juni. In Nederland echter is dit grote haft vermoedelijk reeds tegen het eind van de vorige... |
| Tipo: Article / Letter to the editor |
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| Ano: 1949 |
URL: http://www.repository.naturalis.nl/record/504443 |
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| Dammerman, K.W.. |
| Ofschoon een systematisch onderzoek naar het voorkomen en de verspreiding van zoogdieren in de Noordoostpolder niet heeft plaats gevonden, zijn de gegevens daarover, die in de afgelopen jaren bekend zijn geworden, toch wel van voldoende belang om in een publicatie vast te leggen. Over de zoogdierfauna van Urk en Schokland vóór de drooglegging staan ons maar zeer spaarzame opgaven ter beschikking. Schokland werd in 1933 door Utrechtse biologen bezocht en volgens mededeling van de heer M. F. MÖRZER BRUYNS werden toen in de omgeving van Middelbuurt huismuizen en bruine ratten aangetroffen. In 1940 is de heer MÖRZER BRUYNS begonnen met een hernieuwd onderzoek naar de zoogdierbevolking van Schokland en de N. O. polder, maar na het voorjaar 1941 kon hij zich... |
| Tipo: Article / Letter to the editor |
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| Ano: 1949 |
URL: http://www.repository.naturalis.nl/record/504497 |
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| Slijper, E.J.. |
| 1. A review is given of some phenomena concerning pregnancy and parturition of the Cetacea, depending on data in literature and on observations made in Antarctic Blue and Fin Whales on board the f.f. “Willem Barendsz” (1946—1947). 2. In Mystacoceti the frequency of twins appears to be less than in man and the big domestic animals. The majority of twins is born by females that are longer than the average female in the period of greatest sexual activity. This does not mean, however, that just as in man most twins are born at an elder age than that corresponding with the maximum of sexual activity. It may also be possible that, just as in the big domestic animals, the ages correspond, but that twins are mostly produced by the physically stronger developed... |
| Tipo: Article / Letter to the editor |
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| Ano: 1949 |
URL: http://www.repository.naturalis.nl/record/503926 |
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| Engel, H.. |
| Een feestnummer ter ere van het bereiken van de 70-jarige leeftijd, een mijlpaal, en wel een zeer belangrijke mijlpaal in verband met het daaraan onafwendbaar verbondene emeritaat, verlangt een korte terugblik op alles wat tot nu toe bereikt werd, een verantwoording tevens van de aard dezer publicatie, die een hulde wil zijn van allen, die met de geleerde in aanraking kwamen, als collega’s in binnen- en buitenland, als leerlingen, als vrienden allen. LIEVEN FERDINAND DE BEAUFORT werd geboren de 23e Maart 1879 te Leusden, als zoon van den staatsman en historicus Mr. W. H. DE BEAUFORT. Reeds vroeg trok hem de natuur, die hem door zijn opgroeien op het buiten „Den Treek” bij Amersfoort zo nabij was. Na de H.B.S. te Amersfoort en het z.g. Staatsexamen in 1899... |
| Tipo: Article / Letter to the editor |
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| Ano: 1949 |
URL: http://www.repository.naturalis.nl/record/504078 |
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| Brongersma-Sanders, Margaretha. |
| The number of fish remains occurring in fossil marine deposits varies within wide limits. In many deposits they are rather scarce, sometimes even wholly absent, whereas in some deposits they are common or abundant. According to DEECKE (1913, p. 90) they are scarce in many mesozoic marls, and they are wanting even completely in the devonian Helderberg and Oriskany beds and in the jurassic Opalinus and Renggeri clays. The deposits with a. great number of fish remains are divided by DEECKE into different groups. (The groups that refer to brackish and to supersaline water I shall leave out of consideration). The most important group is represented by certain finegrained sediments that probably were deposited near to the shore; very often these are shales... |
| Tipo: Article / Letter to the editor |
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| Ano: 1949 |
URL: http://www.repository.naturalis.nl/record/504435 |
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| Korringa, P.. |
| Modern oyster culture began its development in the second part of the nineteenth century. Beginning in Europe it gradually spread over all the world’s oyster regions. Locally oyster cultural methods acquired a high degree of technical specialisation, recently even including chemical control of oyster diseases. A steadily increasing stream of scientific and technical papers, dealing with oyster biology and oyster culture, accompanied this development, and already numbers several thousands of publications. If closely related industries, such as cattle-breeding, horticulture, and agriculture, are compared with it, it is clear that one of the basic problems of oyster culture must be the oyster’s nutrition. Without a detailed knowledge of this subject it seems... |
| Tipo: Article / Letter to the editor |
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| Ano: 1949 |
URL: http://www.repository.naturalis.nl/record/504315 |
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| Registros recuperados: 192 | |
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