Showing papers by "University of Geneva published in 1975"
TL;DR: In this article, two children, working together, can successfully perform a task involving spatial coordinations; children of the same age, working alone, are not capable of performing the task.
Abstract: This paper presents two experiments to support the general hypothesis that the coordination of actions between individuals promotes the acquisition of cognitive coordinations. The first experiment shows that two children, working together, can successfully perform a task involving spatial coordinations; children of the same age, working alone, are not capable of performing the task. The second experiment shows that subjects who did not possess certain cognitive operations involved in Piaget's conservation of liquids task acquire these operations after having actualized them in a social coordination task.
367 citations
TL;DR: The development of severe diabetic hyperglycemia requires the presence of glucagon, whether secreted by pancreatic or newly identified gastrointestinal A cells, as well as a lack of insulin, so glucagon suppression could improve therapeutic glucoregulation in diabetes.
Abstract: Glucagon suppression by somatostatin reduces or abolishes hyperglycemia in dogs made insulin-deficient by somatostatin, alloxan, or total pancreatectomy. This suggests that the development of severe diabetic hyperglycemia requires the presence of glucagon, whether secreted by pancreatic or newly identified gastrointestinal A cells, as well as a lack of insulin. Glucagon suppression could improve therapeutic glucoregulation in diabetes.
233 citations
TL;DR: The elevation of DHEA prior to the first signs of puberty suggests thatDHEA may play a role in the maturation of the hypothalamic-hypophysealgonadal axis, however, the mechanism that triggers the secretion of D HEA is not known.
Abstract: In 104 normal boys, ages 7 to 14 years (bone ages 5 to 15 years), plasma dehydroepiandrosterone (DHEA) rose from 52.7 at 7 years, to 112.0 ng/100 ml at 10 years. A further rise occurred at 12 years (188 ng/100 ml). In relation to the bone age, DHEA increased from a mean plasma level of 31.1 at a bone age of 5 years to 77.1 ng/100 ml at one of 7 years. Further increases were observed with mean values of 163.2 at a bone age of 11 years, and of 221.2 at a bone age of 12 years, with a maximum of 333.4 ng/100 ml at bone ages of 14-15 years. The first significant increase of plasma testosterone (T) was noted at a bone age of 12 years (54.8 ng/100 ml). The major rise of T was preceded by the rise of plasma LH and was accompanied by the rise of plasma FSH. Plasma DHEA and T were also measured in 123 normal girls, ages 6 to 13 years (bone ages 5 to 15 years). DHEA rose significantly from a mean level of 44.7 at 6 years, to 80.9 ng/100 ml at 8 years, with further increases between 9 and 10 years and between 10 and ...
197 citations
TL;DR: For the truncated Schwinger functions of the P(Φ)2 field theories, the authors showed strong decrease in the separation of points, and they also extended the domain of analyticity in the coupling constant.
Abstract: For the truncated Schwinger functions of theP(Φ)2 field theories, we show strong decrease in the separation of points. This shows uniqueness of theories withP of degree four. We also extend the domain of analyticity in the coupling constant. For theories withP of degree four, the combination of these two results gives Borel summability.
185 citations
164 citations
TL;DR: Double stranded DNA has been synthesized in vitro from rabbit globin messenger RNA and elongated with homopolymeric dG tails, which yielded a clone which harbours a recombinant plasmid (pCR1-betaG1), as demonstrated by hybridization experiments with radioactive globin cDNA.
Abstract: Double stranded DNA has been synthesized in vitro from rabbit globin messenger RNA and elongated with homopolymeric dG tails. An E. coli plasmid was cleaved by EcoRI. The cohesive ends were repaired and dC tails added, to permit reconstitution of the EcoRI sites upon annealing with the dG elongated globin DNA. Transformation of E. coli with the globin-plasmid DNA hybrid has yielded a clone which harbours a recombinant plasmid (pCR1-betaG1), as demonstrated by hybridization experiments with radioactive globin cDNA. The sequence carried by the recombinant plasmid corresponds to part of the gene sequence coding for the beta chain of rabbit globin. Circular DNA of the purified recombinant plasmid exhibits sensitivity to EcoRI.
144 citations
TL;DR: The presence of gap junctions offers indirect evidence that these cells are coupled with one another; coupling may influence the secretory behavior of alpha- and beta-cells maintaining glucose homeostasis within tightly constricted limits.
Abstract: By degranulating beta-cells in the islets of Langerhans of the rat with sulfonylurea, it has been possible to distinguish unambiguously alpha-cells from beta-cells in freeze-fracture replicas. In such preparations, we found morphologically typical tight and gap junctions occurring between alpha- and beta-cells. The presence of gap junctions offers indirect evidence that these cells are coupled with one another; coupling may influence the secretory behavior of alpha- and beta-cells maintaining glucose homeostasis within tightly constricted limits.
135 citations
TL;DR: Two mechanisms responsible for the increase in Qs/Qt are suggested: 1) redistribution of blood flow to nonventilated areas, resulting from the vasodilating effect of an increased oxygen tension in the vessels of hypoxic lung segments; 2) resorption atelectasis.
Abstract: Twenty patients requiring ventilation for acute respiratory failure were studied to determine whether intrapulmonary shunt fraction (Qs/Qt) measured at an inspired oxygen concentration (FIo2) of 1.0 differs from Qs/Qt measured at the clinically indicated FIo2 and, if so, the mechanism by which this
112 citations
TL;DR: In this paper, the products of three phage genes (N, cII, and cIII ) promote λ repressor synthesis during the infectious cycle of phage λ.
109 citations
TL;DR: In this article, the Butcher-type results for Nystrom-methods have been derived for the first order differential equations of thesecond order and systems of the second order, and a theory for numerical methods for thesecond-order differential equations has been developed.
Abstract: For the numerical solution of differential equations of thesecond order (and systems of ...) there are two possibilities: 1. To transform it into a system of the first order (of doubled dimension) and to integrate by a standard routine. 2. To apply a "direct" method as those invented by Nystrom. The benefit of these direct methods is not generally accepted, a historical reason for them was surely the fact that at that time the theories did not consider systems, but single equations only. In any case the second approach is more general, since the class of methods defined in this paper contains the first approach as a special case. So there is more freedom for extending stability or accuracy.
This paper begins with the development of a theory, which extends our theory for first order equations [1] to equations of the second order, and which is applicable to the study of possibly all numerical methods for problems of this type. As an application, we obtain Butcher-type results for Nystrom-methods, we characterize numerical methods as applications of a certain set of trees, give formulas for a group-structure (expressing the composition of methods) etc.
Recently in [2] the equations of conditions for Nystrom methods have been tabulated up to order 7 (containing errors). Our approach yields not only the correct equations of conditions in a straight-forward way, but also an insight in the structure of methods that is useful for example in choosing good formulas.
105 citations
TL;DR: Freeze-fracture data and biochemical studies demonstrate that hormones and carrier proteins are secreted concomitantly in a great variety of experimental or clinical conditions, without an associated release of granule membrane constituents or of enzymes of cytoplasmic origin.
Abstract: The available evidence suggests that hormones and neurophysins are associated exclusively with the neurosecretory granules, each of which contains approximately 6 times 10-4 molecules of each. Hormones and carrier proteins are complexed within the granules and the complexes are densely packed. The processes that keep the intragranular space in osmotic equilibrium with the axoplasm require further study. Freeze-fracture data, as well as studies in which histochemical methods for the detection of glycoproteins were used, suggest that the intragranular aspect of the granule membrane mostly resembles the extracellular half of the plasma membrane; on the other hand, the cytoplasmic aspects of plasma and granule membrane have similar characteristics, which may be important in permitting membrane fusion to take place prior to secretion. Little is known about the molecular species involved in this interaction between granule and plasma membrane, except that calcium is a cofactor in this process. Release is triggered in vivo by propagated action potentials which cause an influx of calcium into the secretory endings. Newly formed granules, and other granules located at the periphery of the endings are preferentially released. Irrespective of the type of stimulation of secretion, release involves the diffusion into the extracellular space of granule core constituents. The best evidence so far in support of this view comes from ultrastructural studies showing images of exocytosis, as well as from biochemical studies demonstrating that hormones and carrier proteins are secreted concomitantly in a great variety of experimental or clinical conditions, without an associated release of granule membrane constituents or of enzymes of cytoplasmic origin. Recovery mechanisms following secretion require new synthesis of granule constituents and restoration of the resting internal concentrations of potassium, sodium, and calcium. Membrane surface area is restored following exocytosis by compensatory endocytosis which involves indiscriminate uptake of extracellular medium into the secretory axon terminals. While much progress has been made in research on the cellular and subcellular processes that take place in neurons which produce, store, and secrete neurohypophyseal hormones and their carrier proteins, neurophysins, many pressing questions remain to be answered. New developments, such as organ culture of supraoptic nuclei94-96 and the recent isolation of a clone of mouse hypothalamic cells capable of synthesizing vasopressin and neurophysin,97 will hopefully allow some of these problems to be solved in the future.
TL;DR: Elevated binding ratios for both T3 and T4 were found in sera obtained from 5 out of 43 cases of primary hypothyroidism and in 2 out of 34 cases of hyperthyroidism.
Abstract: Anti-thyroxine (T4) and anti-triiodothyronine (T3) antibodies have been demonstrated in man. It was assumed that antibodies were at least partially saturated in vivo by the hormones. The initial step of the method therefore consisted in a dissociation of the postulated antigen-antibody complex by a 45% ammonium sulfate precipitation. The second part of the method consisted in incubating the euglobulins with trace amounts of 125I-T3 and 131I-T4. The hormones bound to the gammaglobulins were then separated from the free hormones by a column of DEAE Sephadex A-50 in ammonium acetate 0.05 M pH 7.6. The amounts of 125I and 131I bound to the gammaglobulin fraction were then measured. The results in any unknown sample were compared to those obtained when an equal amount of standard serum was identically treated, and the results were expressed as unknown/standard ratios of bound 125I and bound 131I, respectively. The mean binding ratios for T3 and T4 found in sera obtained from 42 normal subjects were 0.7 +/- 0.4 SD and 0.8 +/- 0.5, respectively. Elevated binding ratios for both T3 and T4 were found in sera obtained from 5 out of 43 cases of primary hypothyroidism and in 2 out of 34 cases of hyperthyroidism. The binding ratios were elevated for only T3 in 10 cases of primary hypothyroidism and in 5 cases of hyperthyroidism. Antibodies against T4 were detected in one case of primary hypothyroidism. High binding ratios for T3 were also observed in one patient with secondary hypothyroidism who had received treatment with dessicated thyroid for several years. In most of the positive sera, anti-thyroglobulin antibodies, as measured by passive hemagglutination, could also be detected. For one serum containing anti-T3 antibody and another containing anti-T4 antibody, the binding affinity and capacity were estimated by Scatchard plot analysis; affinity constants were 5.4 x 10(8) L/mol and 1.3 x 10(9) L-mol, respectively; capacities 1.4 ng/ml and 1.2 ng/ml, respectively. The presence of anti-T3 and anti-T4 antibodies in serum may result in an apparent lowering of the serum T3 and T4 concentrations, respectively.
TL;DR: In this paper, a family of external potentials for the Dirac equation is exhibited for which there is an exact SU(2) symmetry leading to exact spin-orbit doublet degeneracy.
TL;DR: It is concluded that Ca2+, which plays an essential role in the stimulus-secretion coupling in several different cell types, may be involved in the stimulation of glucagon release from the A-cells of the pancreas.
TL;DR: The results indicate that the replication time of the chromosome is constant and independent of the doubling time of a strain of Escherichia coli K12.
TL;DR: Activation of p rm, the promoter at which cI transcription is initiated in immune bacteriophage lambda lysogens, requires no phage genes or sites outside the cI region, cro product, however, is able to reduce fivefold the efficiency of cI expression from this promoter.
TL;DR: Experiments using cycloheximide suggest that MPF does not need protein synthesis for germinal vesicle breakdown (GVBD), but does require a translational step when serially transferred in order to sustain its renewal ("autocatalytic") capacity.
TL;DR: In this article, it is predicted that the rate of development of concrete operations may be partly determined by ecological and cultural factors, and the results of a study involving 190 children (aged six to fourteen from three cultural groups: Canadian Eskimos, Australian Aborigines, and Ebrie Africans).
Abstract: Berry's (1971) model of ecological functionalism is extended to Piagetian developmental psychology. It is predicted that the rate of development of concrete operations may be partly determined by ecological and cultural factors. In particular, if three subsistence-economy populations are placed on an ecocultural scale, with low food-accumulating, nomadic, hunting groups at one extreme, and high food-accumulating, sedentary, agricultur-alist groups at the other extreme, the former are expected to develop spatial concepts more rapidly than will the latter, whereas the sedentary group is expected to attain concepts of conservation of quantity, weight, and volume more rapidly than nomadic groups will. The model is largely supported by the results of a study involving 190 children (aged six to fourteen from three cultural groups: Canadian Eskimos, Australian Aborigines, and Ebrie Africans. The discussion centers on ambiguous results obtained in the age range eight to eleven years for the conservation tasks.
TL;DR: In this article, the title compounds have been examined by X-ray methods in the temperature range between -170 °C and 1000 °C, and they transform from an orthorhombic centrosymmetric (low-temperature, Ru2Ge3 type) to a tetragonal non-centrosymetric (hightemperature) crystal structure.
Abstract: The title compounds have been examined by X-ray methods in the temperature range between -170 °C and 1000 °C. They transform from an orthorhombic centrosymmetric (low-temperature, Ru2Ge3 type) to a tetragonal non-centrosymmetric (high-temperature, Ru2Sn3 type) crystal structure. These transformations are reversible, result from the displacement of Si, Ge, and Sn atoms, and occur gradually over a wide temperature range.
TL;DR: In this article, N-Acyl-N-(4-penten-1-yl)-1-amino-1, 3-butadiene isomerisieren sich bei 190-215° uber eine intramolekulare Diels-Alder-Reaktion stereoselektiv zu cis- verknupften Octahydro-chinolinen 2.
Abstract: N-Acyl-N-(4-penten-1-yl)-1-amino-1, 3-butadiene (1) isomerisieren sich bei 190-215° uber eine intramolekulare Diels-Alder-Reaktion stereoselektiv zu cis- verknupften Octahydro-chinolinen 2. Unter den gleichen Bedingungen erhalt man aus dem N(Pent-4-enoyl)-N-propyl-1-amino-1, 3-butadien (4) uberwiegend das trans-verknupfte Octahydrochinolin-2-on 5 neben dem cis-Isomeren 6. Diese Selektivitat wird auf eine bevorzugte koplanare Anordnung von Amid- und Dien-System im Ubergangszustand zuruckgefuhrt.
TL;DR: In this paper, the solid solutions PbyMo6X8−xX′x and Mo6X 8−x X′x (X, X′ = S, Se, Te) are studied and it is shown that there are correlations between Tc and certain structural parameters.
TL;DR: The freeze-fracturing technique was applied to fresh human islets of Langerhans, and the inside of cellular membranes was revealed, and specific membrane differentiations, hitherto unknown, were observed in the plasma membrane of the endocrine cells.
Abstract: The freeze-fracturing technique was applied to fresh human islets of Langerhans. With this technique, the inside of cellular membranes was revealed, and specific membrane differentiations, hitherto unknown, were observed in the plasma membrane of the endocrine cells. The specific membrane differentiations represent two types of intercellular junctions, namely the tight junction, which determines a closure of the extracellular space and the gap junction which allows molecules and ions to diffuse from one cell to another (sharing the gap junction) without leaking in the extracellular space (intercellular coupling). The presence of such junctions may be important for the secretory behavior of the cells within the islet.
01 Jan 1975
TL;DR: In this paper, it is shown that the atomicity and the covering law can be justified on the basis of a new and more satisfactory notion of state and the existence of ideal measurements of the first kind.
Abstract: It is shown that the axiom of atomicity and the covering law can be justified on the basis of a new and more satisfactory notion of state and the existence of ideal measurements of the first kind. These two axioms are thereby given a satisfactory justification in terms of empirical facts known about micro-systems. Furthermore the new notion of state introduced here does not involve any probability statements and there is therefore no difficulty attributing it to individual systems, which was not possible with the notion heretoforth used in quantum mechanics.
TL;DR: Virus strain and host cell did affect the relative amounts of antigenomes in both mature virions and the infected cell, but in all cases more antigenomes were present in theinfected cell than would be expected from their function as intermediates in genome replication.
TL;DR: In this paper, a distinction is made between behavioral style (in the face of the majority norm) and the style of negotiation, which is the negotiation style the minority wants to influence.
Abstract: The new theoretical presuppositions used by Moscovici to explain social influence phenomena led him to show that the consistency of behavior can account for the influence of a minority. Experimental data confirm this idea. However, some counter-examples, showing that consistency sometimes induces subjects to refuse compromises, are problematical. To clear up this apparent contradiction, a distinction is made between behavioral style (in the face of the majority norm) and the style of negotiation (in the face of the population the minority wants to influence). A first experiment, then, shows that when two minorities are seen as equally consistent, the minority with a flexible style of negotiation has more influence than the more rigid minority. A second experiment deals with Ss' perception of the source of influence and clarifies the effects of minority negotiations; the links between opinions, opinion change and perception of others are also clarified.
TL;DR: Nuclear transplantation experiments show that differentiated cells, such as lymphocytes, from the adult frog can express the genes necessary for tadpole development.
Abstract: Nuclear transplantation experiments show that differentiated cells, such as lymphocytes, from the adult frog can express the genes necessary for tadpole development. The transplanted cells were proven to be lymphocytes by immunological methods. The origin of the tadpoles that developed after lymphocyte nuclei injections was ascertained by a karyotypic marker.
TL;DR: There is no mitochondrion in the two Onchobothriidae sperms studied and the body which appears on cross-sections as crest, lateral with respect to the axoneme, is present in both species.
Abstract: Les premiers stades de la spermatogenese, la differenciation et l'ultrastructure du spermatozoide de Acanthobothrium filicolle benedenii Loennberg, 1889 sont etudies en detail et compares a ceux de Onchobothrium uncinatum (Rud, 1819)
TL;DR: In this article, the erste Totalsynthese des racemischen Alkaloids Pumiliotoxin-C (9) ausgehend von trans-1-Brom-3-penten (1) wird beschrieben.
Abstract: Die erste Totalsynthese des racemischen Alkaloids Pumiliotoxin-C (9) ausgehend von trans-1-Brom-3-penten (1) wird beschrieben. Die Schlusselstufe 6 -> 7 verlauft uber eine intramolekulare Diels-Alder-Reaktion unter weitgehender sterischer Kontrolle von vier Chiralitatszentren. Die Struktur des synthetischen Produkte 9 wurde durch eine Rontgenstrukturanalyse des kristallinen Hydrogenmaleinates bestatigt.
TL;DR: In this article, the branching ratio assuming a uniform phase space distribution is found to be (2.6 ± 0.5) × 10 −7, where 10 − 7 is the number of particles in the phase space.
TL;DR: The two sulfonylureas were extensively metabolized and were excreted in the urine as hydroxylated or conjugated metabolites and the effects of both drugs on blood glucose and immunoreactive insulin were comparable.
Abstract: Four subjects received 5 mg14C-glipizide orally, 3 subjects 1 mg intravenously and 2 subjects 5 mg14C-glibenclamide orally. Plasma levels of radioactivity, and urinary and faecal excretion were measured. For both drugs the disappearance of radioactivity from plasma followed complex kinetics and the apparent half-lives increased steadily with time. The two sulfonylureas were extensively metabolized and were excreted in the urine as hydroxylated or conjugated metabolites. The effects of both drugs on blood glucose and immunoreactive insulin were comparable. The findings are compared with other published results.