Showing papers by "University of Amsterdam published in 1968"
Book•
01 Jan 1968TL;DR: A history of economic thought from Adam Smith to John Maynard Keynes is presented in the fifth edition of the Reader's Guide to Economics as discussed by the authors, which includes new Reader's Guides to Walras's Elements of Pure Economics and Keynes' General Theory.
Abstract: This is a history of economic thought from Adam Smith to John Maynard Keynes - but it is a history with a difference. Firstly, it is a history of economic theory, not of economic doctrines, that is, it is consistently focused on theoretical analysis, undiluted by entertaining historical digressions or biological colouring. Secondly, it includes detailed Reader's Guides to nine of the major texts of economics, namely the works of Smith, Ricardo, Mill, Marx, Marshall, Wickstead, Wicksell, Walras and Keynes, in the effort to encourage students to become acquainted at first hand with the writings of all the great economists. This fifth edition, first published in 1997, adds new Reader's Guides to Walras's Elements of Pure Economics (1871–74) and Keynes' General Theory to the previous seven Reader's Guides of other great books in economics. There are significant and major additions to six chapters.
1,031 citations
Journal Article•
TL;DR: To what extent an average-response computer can be utilized for computing a cross-correlation function is shown, and two methods are described, both with respect to the results and to the accuracy obtainable.
Abstract: This paper shows to what extent an average-response computer can be utilized for computing a cross-correlation function. This type of computer needs synchronization pulses, and the simplest methods of computation are those in which these pulses are directly derived from one of the signals (triggered correlation). The first method is to generate a synchronization pulse whenever the signal crosses a pre-set threshold in any direction. In this case, the computer output function is shown to be proportional to the true correlation function, for Gaussian signals. In a second method, synchronization pulses are produced when the signal crosses the threshold in a specified (e.g., positive) direction. Then the computer output is found to be contaminated by a systematic error, which, in turn, depends on the derivative of the correlation function. These two methods are described in detail, both with respect to the results and to the accuracy obtainable. Several other, less important, methods are only briefly described.
435 citations
TL;DR: It was shown that bifidobacteria convert mannitol to fructose-6-phosphate by an inducible polyol dehydrogenase and fructokinase and the phosphoroclastic enzyme could not be demonstrated in cell-free extracts.
Abstract: For six strains of Bifidobacterium bifidum (Lactobacillus bifidus), fermentation balances of glucose, lactose, galactose, mannitol, and xylose were determined Products formed were acetate, l(+)-lactate, ethyl alcohol, and formate l(+)-Lactate dehydrogenase of all strains studied was found to have an absolute requirement for fructose-1,6-diphosphate The phosphoroclastic enzyme could not be demonstrated in cell-free extracts Cell suspensions fermented pyruvate to equimolar amounts of acetate and formate Alcohol dehydrogenase was shown in cell-free extracts Possible explanations have been suggested for the differences in fermentation balances found for different strains and carbon sources By enzyme determinations, it was shown that bifidobacteria convert mannitol to fructose-6-phosphate by an inducible polyol dehydrogenase and fructokinase For one strain of B bifidum, molar growth yields of glucose, lactose, galactose, and mannitol were determined The mean value of Y (ATP), calculated from molar growth yields and fermentation balances, was 113
174 citations
TL;DR: An experimental equipment permitting the study of freshwater snails under regulated conditions, continuous water change included, is described and Lymnaea stagnalis can be bred in large densities under these conditions, without growth and reproduction being interfered with.
Abstract: 1 An experimental equipment permitting the study of freshwater snails under regulated conditions, continuous water change included, is described 2 Lymnaea stagnalis can be bred in large densities under these conditions, without growth and reproduction being interfered with 3 Attention is called to the methodical import of continuous water change in experimental work
122 citations
TL;DR: For the muscle enzyme under experimental conditions, a model in which the binding of 1 NAD + molecule to one protomer affects the conformation of a second protomer, either before or after binding with NAD + , appear more appropriate than the allosteric model, which requires that thebinding of any one ligand molecule is intrinsically independent of the Binding of any other.
99 citations
TL;DR: A rather gradual curvature was found for the In D versus 1/T plot for tracer-self-diffusion in nickel single crystals at temperatures from 980 to 1400 °C.
Abstract: A rather gradual curvature was found for the In D versus 1/T plot for tracer-self-diffusion in nickel single crystals at temperatures from 980 to 1400 °C. The activation energies and frequency factors at the highest and lowest temperatures were in agreement with values measured by other investigators in a similar temperature region. It proved to be possible to analyse the curve in terms of contributions of single and multiple vacancies. Especially accurate values of the characteristic quantities for the diffusion via single vacancies were obtained. Other possible explanations of the curvature were investigated, but rejected.
Eine ziemlich gleichmasig verlaufende Krummung wurde in der graphischen Darstellung von In D gegen 1/T fur Tracerselbstdiffusion in einkristallinem Nickel bei Temperaturen von 980 bis 1400 °C gefunden. Die Aktivierungsenergien und Frequenzfaktoren bei den hochsten und niedrigsten Temperaturen waren in Ubereinstimmung mit den Werten anderer Experimentatoren im gleichen Temperaturgebiet. Es erwies sich als moglich, die Kurve in Beitrage von einfachen und mehrfachen Leerstellen zu zerlegen. Insbesondere wurden genaue Werte fur die charakteristischen Grosen der Diffusion uber einfache Leerstellen gefunden. Andere mogliche Erklarungen fur die Krummung wurden untersucht, aber verworfen.
97 citations
TL;DR: The action of the vagal nerves on the transmembrane potentials of fibres in the S-A node was studied in the isolated right atrium of rabbit hearts, where the maximal diastolic potential increases, the amount of hyperpolarization being maximally 25 mV.
Abstract: The action of the vagal nerves on the transmembrane potentials of fibres in the S-A node was studied in the isolated right atrium of rabbit hearts. During vagal stimulation the transmembrane potential shows several changes:
96 citations
TL;DR: Some osmium tetroxide-fixed preparations showed a differentiation in cytoplasm and nucleoplasm, which made it possible to observe the close association of the mesosome with the latter.
Abstract: Freeze-etched cells of Bacillus subtilis have been studied with the electron microscope. The outer surface of the plasma membrane, i.e. the side facing the cell wall, is covered with numerous granules and short strands, each measuring approximately 50 A in diameter. These strands are occasionally seen to enter the cell wall. The inner surface of the plasma membrane, i.e. the side facing the cytoplasm, appears to be sparsely dotted with small particles measuring about 50 A. The envelope of mesosomes differs from the plasma membrane. Blunt protrusions arise from its outer surface; the inner surface appears smooth. Stalked particles, as described by other investigators after negative staining with phosphotungstic acid, were not observed on any membrane surface in our material. Preparations were also made of specimens prefixed in osmium tetroxide prior to freeze-etching. Under these conditions the bacterial membranes appeared to be surprisingly well preserved. In contrast to directly frozen, unfixed cells, some osmium tetroxide-fixed preparations showed a differentiation in cytoplasm and nucleoplasm, which made it possible to observe the close association of the mesosome with the latter.
71 citations
TL;DR: A scheme is proposed by which various forms of intraventricular conduction disturbance can be defined in terms of block of one or more divisions of a three-pronged system of rapid ventricular excitation.
Abstract: Interruption of anterior fibers of the left bundle branch system together with right bundle branch block was accomplished experimentally in canine and primate hearts. In both species the electrocardiographic effects included a major alteration of the mean electrical axis to a superior and anterior direction. Epicardial excitation was markedly delayed anteriorly, causing widening of the QRS complex in standard electrocardiographic leads. Normal outward intramural spread of excitation in anterior regions of the left ventricle was reversed after left anterior arborization block alone. After addition of right bundle branch block, intramural spread of excitation was again directed outwardly but was markedly delayed in endocardial onset. Electrical effects of these blocks could be "corrected" individually or in combination by introducing synchronized electrical stimuli distal to each lesion. A scheme is proposed by which various forms of intraventricular conduction disturbance can be defined in terms of block of one or more divisions of a three-pronged system of rapid ventricular excitation.
70 citations
TL;DR: From spectroscopic analysis of purified samples, it appears that the hormones are identical with trisporic acids B and C, evidence for the hypothesis that the sex hormones are produced by B. trispora-plus only.
Abstract: When stimulated by equivalent amounts of progametangia-inducing hormones, cultures of the minus mating type of Blakeslea trispora produce about the same quantities of carotenoids as mated cultures of the fungus, which suggests that the stimulation of carotene synthesis during the sexual activity of mated cultures is the result of hormonal action. These hormones were isolated and purified. From spectroscopic analysis of purified samples, it appears that the hormones are identical with trisporic acids B and C. When both mating types of B. trispora were cultivated in one vessel but were kept apart by membrane filters, the formation of sex hormones was not inhibited. Physical contact between the mating types is obviously not required for the induction of sexual activity. The sex hormones also formed in combined cultures of B. trispora-plus and Zygorhynchus moelleri (a homothallic species), but not in combined cultures of B. trispora-minus and Z. moelleri. This is evidence for the hypothesis that the hormones are produced by B. trispora-plus only.
68 citations
TL;DR: It is suggested that a specific carrier for α-oxoglutarate may exist, analogous to those proposed by Chappell and Haarhoff for other anions, and that malonate increases the permeability of the mitochondria for this oxo-acid.
TL;DR: In this paper, a description of the anisotropy energy with cubic harmonics is given and the first six constants in this description have been calculated at 296, 195, 77, 20 and 4.2 K.
TL;DR: In this article, a series of rare-earth intermetall intermetallic compounds have been measured and the exchange integral Γ = 2 J(0) and the Fermi wave vector kF is found to be a continuous function of kF with a sign reversal at kF ≈ 1.4 A−1.
Abstract: Measurements of the Knight shifts and susceptibilities of rare-earth intermetallic compounds have been extended to YCu, GdCu, TbCu, DyCu, HoCu, and ErCu. The phenomenological exchange constants sf between 4f-electron spins and conduction-electron spins are derived to be −0.21 eV. Also the paramagnetic Curie temperatures of the compounds GdCu1−xGax have been measured. The Knight shifts and Curie temperatures are discussed in terms of the Ruderman-Kittel-Kasuya-Yosida theory. For the various series of rare-earth intermetallic compounds the s-f exchange integral Γ = 2 J(0) and the Fermi wave vector kF have been determined. Γ is found to be a continuous function of kF, with a sign reversal at kF ≈ 1.4 A−1. This observed behavior is consistent with the calculations of Watson, Koide, Peter, and Freeman on the effect of interband mixing on the exchange interactions.
Messungen der Knight-shifts und der Suszeptibilitaten der intermetallischen Verbindungen der Seltenen Erden wurden auf YCu, GdCu, TbCu, DyCu, HoCu und ErCu ausgedehnt. Die phanomenologischen Austauschkonstanten sf zwischen den Spins der 4f-Elektronen und den Spins der Leitungselektronen wurden zu −0,21 eV bestimmt. Die paramagnetischen Curietemperaturen der Verbindungen GdCu1−xGax wurden ebenfalls gemessen. Die Knight-shifts und die Curie-Temperaturen werden mit der Ruderman-Kittel-Kasuya-Yosida-Theorie diskutiert. Fur die verschiedenen Serien der intermetallischen Verbindungen der Seltenen Erden wurden das s–f-Austauschintegral Γ = 2 J(0) und der Fermi-Wellenvektor kF bestimmt. Es wurde gefunden, das Γ eine stetige Funktion von kF ist, mit einem Vorzeichenwechsel bei kF ≈ 1,4 A−1. Dieses Verhalten stimmt mit den Berechnungen der Wirkung der Interbandmischung auf die Austauschwechselwirkung von Watson, Koide, Peter und Freeman uberein.
TL;DR: Specimens of the lung taken for biopsy at operation on 80 patients with complete transposition of the great vessels were histologically studied in correlation with the clinical and hemodynamic data in these cases, and intimal fibrosis was suggestive of organized thrombi.
Abstract: Specimens of the lung taken for biopsy at operation on 80 patients with complete transposition of the great vessels were histologically studied in correlation with the clinical and hemodynamic data in these cases. In a group of 31 cases of intact ventricular septum and patent foramen ovale, the media of the pulmonary arteries was generally thinner than normal, and to a lesser extent that of the pulmonary veins was also, while the lumina of the vessels were wide. This was especially observed in cases in which the hematocrit was high. Possibly, this phenomenon is based on dilatation of the arteries and is related to the increased total blood volume. Intimal fibrosis, when observed, was suggestive of organized thrombi. In a group of 28 patients with ventricular septal defect and equal pressures in the left and right ventricles, there was generally marked medial hypertrophy and concentric intimal proliferation in the pulmonary arteries. In cases of pulmonic stenosis, on the other hand, the media of the pulmon...
TL;DR: Functional left bundle-branch block by retrograde invasion into the left bundle branch is thought to be responsible for left aberrant conduction changing into nonaberrants conduction after a ventricular premature beat.
Abstract: A description is given of a patient with an atrioventricular nodal tachycardia with left aberrant conduction changing into nonaberrant conduction after a ventricular premature beat. Functional left bundle-branch block by retrograde invasion into the left bundle branch is thought to be responsible for this phenomenon.
TL;DR: In this paper, the authors measured the phosphoresence spectra of phenanthrene and naphthalene in liquid ethanol solutions and ascribed the structured component to the triplet monomer, the structureless one to triplet excimer phosphorescence emission. Decay constants for the two emissions have been measured as a function of the temperature.
TL;DR: Substrates inhibit competitively the uptake of other substrates and the maximal uptake (at infinite external substrate concentration) is finite and approximately equivalent to the intramitochondrial K + concentration.
TL;DR: A fifth patient is presented, a sib of the patient described by Holleman et al. (1966), who had the diagnosis made during life, by the assay of the branching enzyme activity in leucocytes, and an attempt was made to treat the child with oc-glucosidase, and with zinc- glucagon, both administered parenterally.
Abstract: Type IV glycogen storage disease is caused by a deficiency of the branching enzyme, oc-1,4-glucan: ox-1,4-glucan 6-glucosyltransferase, EC 2.4.1.18 (Brown and Brown, 1966); and is characterized by the accumulation in liver, spleen, and other organs of glycogen with an abnormal structure. This glycogen has long outer chains, relatively few branch points, and gives a blue colour with iodine. It thus resembles amylopectin, and the disease is sometimes called amylopectinosis. The disease is rare, and only 4 patients have been described (Andersen, 1956; Sidbury et al., 1962; Brown and Brown, 1966; Holleman, van der Haar, and de Vaan, 1966). We present a fifth patient, a sib of the patient described by Holleman et al. (1966). The diagnosis was made during life, by the assay of the branching enzyme activity in leucocytes. An attempt was made to treat the child with oc-glucosidase, and with zinc-glucagon, both administered parenterally.
TL;DR: Enterobacter cloacae (strain DF13) was found to produce a bacteriocin which could be induced by mitomycin C, and it was shown that these two factors are two separate genetic entities.
Abstract: Enterobacter cloacae (strain DF13) was found to produce a bacteriocin which could be induced by mitomycin C. In the supernatant fluid of the induced culture phagelike particles were found. The bacteriocin was partially purified from induced cultures by ammonium sulfate precipitation and gel-filtration on Sephadex G-150. Ultraviolet-absorbing material was eluted from the Sephadex column in three fractions. The biological activity was mainly present in the second fraction and is associated with a protein with a molecular weight of about 61,000. The phagelike particles were found in the first fraction and show no biological activity. Upon conjugation of E. cloacae strain DF13 with another strain of the same species and with Escherichia coli K-12S, the ability to produce bacteriocin was transferred. The new bacteriocinogenic strain produced bacteriocin, which could not be distinguished from that produced by E. cloacae strain DF13. Although transfer of the bacteriocinogenic factor often occurred together with transfer of the ability to produce phagelike particles, it was shown that these two factors are two separate genetic entities. In addition to a bacteriocinogenic factor, E. cloacae strain DF13 was found to carry two other transferable plasmids: one determining resistance against streptomycin and sulfanilamide and another determining resistance against penicillin.
TL;DR: It could be concluded that migration did not occur in the surface dwelling Collembola Tomocerus minor, made possible by its adaptation to lower temperature conditions, and Lepidocyrtus cyaneus, Orchesella cincta, Entomobrya nivalis and Isotoma viridis appeared to have two generations per year.
Abstract: 1 The population structure of the surface dwelling Collembola Tomocerus minor (Lubbock), Lepidocyrtus cyaneus Tullberg, Orchesella cincta (Linne), Entomobrya nivalis (Linne), Isotomurus palustris (Muller) and Isotoma viridis Bourlet was studied between May 1963 and September 1964 2 Temperature appeared to be an important cause in starting growth and reproduction in spring in all species 3 Reproduction took place throughout spring, summer and autumn, the details being slightly different in the various species In winter no reproduction occurred 4 Lepidocyrtus cyaneus, Orchesella cincta, Entomobrya nivalis and Isotoma viridis appeared to have two generations per year Tomocerus minor has three generations per year, made possible by its adaptation to lower temperature conditions 5 After each egg-laying period a high adult mortality was obvious 6 The species hibernated as half-grown individuals The hibernating populations consisted of two generations 7 During winter about half the populations of the six species died This must be due to weathers factors, as predators were hardly active anymore 8 On the basis of activity observations, it could be concluded that migration did not occur
TL;DR: It is proposed that dinitrophenol may enter the mitochondria via a number of carrier systems specific for different types of anion, including acetate, malonate, l -aspartate, pyruvate and, especially, by tricarballylate, which can be explained by competition with dinitrosthenol for penetration of the mitochondrial matrix.
TL;DR: The conclusion is drawn that the intact mitochondrial DNA of yeast is substantially larger than 5 μ, compared with standard purification procedures and by osmotic shock.
TL;DR: Results of Michaelis-Menten constant measurements for the linear essentially unbranched dextran fractions used, indicate that the affinity of the enzyme for the non-reducing end group of thedextran molecule increases with increasing molecular weight of the acceptor.
Abstract: A modified method for the histochemical demonstration of the activity of α-glucan phosphorylase is described. In the histochemical system the enzyme catalyses the synthesis of glycogen by transglucosylation from α-d-glucosylphosphate. The incubation medium contains dextran as glucosyl acceptor. Therefore, in contrast with the unmodified method, the new technique is able to demonstrate the activity of phosphorylase in ischaemic glycogen-depleted tissues.
TL;DR: During a random rhythm the contractile parameters of an isolated heart are strongly related to the preceding RR interval, and it is conceivable that this relation contributes to the variability of hemodynamic parameters during atrial fibrillation in man.
Abstract: Hemodynamic variability in patients with atrial fibrillation may originate from a direct influence of the variations in RR intervals on myocardial contractility. With the aid of a computer the serial autocorrelation function and the histogram of the RR intervals of patients with atrial fibrillation receiving no medication were produced. The RR intervals were randomly distributed and the histograms rather skew. Next, random rhythms with histograms matching those of the patients were produced with a radioactive source and a Geiger-Muller counter. These rhythms were used to stimulate isolated perfused rat hearts to study the relationship between the RR interval and a number of contractile parameters. The ECG and the isotonic contractions were digitized and processed by the computer. Serial crosscorrelation coefficients were computed between the RR interval on the one hand, and contraction height, contraction area, and maximum of the first derivative of the contraction on the other hand. The zero order cross...
TL;DR: Starting with a population of Tetranychus urticae, a number of lines were inbred by sibmating for seven generations and a diversity of response curves was obtained, indicating that great genetic variability of photoperiodic response existed in the original colony.
Abstract: Starting with a population of Tetranychus urticae, a number of lines were inbred by sibmating for seven generations. When these inbred lines were exposed to different photoperiodic regimens, a diversity of response curves was obtained. This indicated that great genetic variability of photoperiodic response existed in the original colony.
From reciprocal mass-crosses between one line, characterized by a low level response (LR), and several lines which showed a nearly saturated photoperiodic response (HR), it was concluded that HR was dominant over LR. From a study of the backcrosses to LR-males, it appeared that the transmission of the character was different in the two types of F1-hybrids. The difference could be explained by assuming a cytoplasmic determinant. The possibility that the difference in inheritance resulted from a peculiar haplo-diploid sex-determination was also considered.
Zusammenfassung
GENETISCHE VARIABILITAT DER PHOTOPERIODISCHEN REAKTION BEI EINER ARRHENOTOKEN MILBE (TETRANYCHUS URTICAE)
Von einer Wildpopulation der Spinnmilbe Tetranychus urticae von Sambucus ausgehend, wurden durch. Geschwisterpaarung uber 7 Generationen ***eine Anzahl Tnzucht-Linien gezuch***let. Wenn diese Inzucht-Linien verschiedenen Tageslangen ausgesetzt wurden, ergaben sich unterschiedliche photoperiodische Wirkungskurven bezuglich der Diapause-Reaktion. Diese weisen auf das Vorhandensein einer grosen genetischen Variabilitat in der photoperiodischen Reaktion der Ausgangspopulation hin.
Aus reziproken Massenkreuzungen zwischen einer durch einen niedrigen Reaktionsspiegel (LR) gekennzeichneten Linie mit verschiedenen Linien mit nahezu vollstandiger, photoperiodisch bedingter Diapause-Reaktion (HR) wird geschlossen, das HR (hohe Diapause-Auslosung) uber LR (schwache Diapause-Auslosung) dominant ist. Aus einer Untersuchung von Ru***ckkreuzungen der weiblichen Hybriden mit LR-Mannchen ergibt sich, das die Weitergabe der Reaktionseigenschaft bei den beiden Typen der F1-Bastarde (HR × LR bzw. LR × HR) anscheinend verschieden ist. Der Unterschied konnte mit der Annahme eines cytoplasmatischen Vererbungsfaktors erklart werden. Doch wird auch die Moglichkeit erwogen, das der Unterschied im Erbgang durch die Besonderheit einer geschlechtsgebundenen haplo-diploiden Vererbung bedingt sei.
01 Apr 1968
TL;DR: The probable identity of the fossil pollen of Oligocene to Miocene age described as Psilatricolporites crassus Hammen & Wijmstra and that of the recent Theacea Pelliciera rhizophorae Planch have been established and the occurrence in the past is compared with the recent distribution of Pellicira.
Abstract: The probable identity of the fossil pollen of Oligocene to Miocene age described as Psilatricolporites crassus Hammen & Wijmstra and that of the recent Theacea Pelliciera rhizophorae Planch. & Triana has been established. The occurrence in the past is compared with the recent distribution of Pelliciera.
TL;DR: Experiments with several groups of chemically related substances showed that differences in penetration into the vitreous body of the rabbit must be attributed to the existence of a Vitreous barrier.
TL;DR: It is concluded that the medulla of the MDB should not be regarded as a “neurosecretory neuropile”, and apparently theMDB-cerebral ganglion complex is no neuroendocrine association.
Abstract: In Basommatophora medio-dorsal bodies (MDB) are closely attached to the cerebral ganglia, in which, just underneath the bodies, groups of Gomori-positive neurosecretory cells (MDC) occur. It has been suggested that the MDB-cerebral ganglion complex should be regarded as a neuro-endocrine association.