Systematic variation of the stellar initial mass function in early-type galaxies

Much of our knowledge of galaxies comes from analysing the radiation emitted by their stars, which depends on the present number of each type of star in the galaxy. The present number depends on the stellar initial mass function (IMF), which describes the distribution of stellar masses when the population formed, and knowledge of it is critical to almost every aspect of galaxy evolution. More than 50 years after the first IMF determination, no consensus has emerged on whether it is universal among different types of galaxies. Previous studies indicated that the IMF and the dark matter fraction in galaxy centres cannot both be universal, but they could not convincingly discriminate between the two possibilities. Only recently were indications found that massive elliptical galaxies may not have the same IMF as the Milky Way. Here we report a study of the two-dimensional stellar kinematics for the large representative ATLAS(3D) sample of nearby early-type galaxies spanning two orders of magnitude in stellar mass, using detailed dynamical models. We find a strong systematic variation in IMF in early-type galaxies as a function of their stellar mass-to-light ratios, producing differences of a factor of up to three in galactic stellar mass. This implies that a galaxy's IMF depends intimately on the galaxy's formation history.     

Binding of indole-acetic acid to cytosol proteins of embryonic chicken liver

Summary ³H-Indole acetic acid bound to cytosol proteins of embryonic chicken liver in vitro to an average capacity of at least 20 pmoles/mg binding protein. The auxin-binding protein complexes could be resolved into 4 major zones by anion exchange chromatography; they sedimented at 3–7 S in sucrose density gradients, and were also heterogenous in agarose gel electrophoresis.     

Immunological unresponsiveness in chickens induced by human γ-globulin

Zusammenfassung Wiederholte Injektionen von menschlichem -Globulin in der ersten Nachgeburtsperiode, führte bei Kücken zu immunologischer Toleranz gegenüber diesem Antigen.     

Potassium-stimulated respiration of cerebral cortex of rats poisoned with phosphamidone

Résumé Chez le rat intoxiqué par des doses léthales de phosphamidone, la consommation in vitro d'oxygène des tranches du cortex cérébral stimulées par KCl est plus élevée que celles des témoins ou des rats intoxiqués au paraoxon ou au TEPP.     

The effect of γ-irradiation on the amount of 5-hydroxytryptamine in the gut and spleen in the early phase after irradiation

Résumé 24 et 48 h après irradiation- (900 r) la quantité de 5-hydroxytryptamine dans l'intestin du rat n'a pas changé de manière significative. La quantité de 5-hydroxytryptamine dans la rate du rat, exprimée par g de tissu frais a augmenté. Le prétraitement avec de la cystéamine abaisse nettement la quantité de 5-hydroxytryptamine dans la rate, après l'irradiation.     

Distribution of DNA and RNA in different regions of cat's brain

Résumé Chez le chat normal, la concentration d'ADN est à peu près la même dans les diverses régions examinées du système nerveux central. Par contre, la concentration d'ARN varie considérablement d'une région à l'autre. Ces résultats suggèrent que la distribution de l'ARN correspond à la différentiation morphologique et fonctionnelle des parties du cerveau.     

On the glutamine and γ-aminobutyric acid contents of various regions of the cat brain

Résumé Les auteurs ont déterminé par la méthode de la chromatographie à deux dimensions, la teneur en glutamine et en acide -aminobutyrique des différentes parties du cerveau du chat. La concentration la plus élevée de l'acide -aminobutyrique a été trouvé dans l'hypothalamus, tandis que celle de la glutamine a été constatée dans le noyau caudé. Les concentrations les plus basses de ces deux protéines apparaissent dans la substance blanche du cerveau.     

The effect of some anticholinesterase agents and of hemicholinium on the amount of substance P in rabbit brain and gut

Résumé Les substances anticholinestérasiques s'avèrent capables de réduire la concentration en substance P du cerveau et de l'intestin du lapin. Cependant l'hémicholinium No 3 augmente la concentration de la substance P de l'intestin et diminue celle du cerveau.     

Antigenic correlation between rat brain synaptic vesicles and rat bone marrow B lymphocytes

Summary Rabbit anti-rat brain synaptic vesicle serum reacted with thymocytes and B lymphocytes in cytotoxicity and immunofluorescence assays. Quantitative absorption analysis revealed that this antiserum contained antibodies specific for antigenic determinants on the surface membrane of a subpopulation of rat bone marrow B lymphocytes.This work was supported by the Republic of Serbia Research Fund, Belgrade.     

Diminution de radiosensibilité du rat adulte en hypothermie profonde

Summary Using an appropriate technique, we put adults rats of both sexes under deep hypothermy (rectal temperature of 14–15°C). Under these conditions, the respiration and the cardiac rhythm are definitely slowed down.(1) Rats irradiated in a state of deep hypothermy with lethal doses of 800 and 900 r of X-rays, are partially protected. 50% of these animals survived more than 30 days, whereas all control animals died after 17 days.(2) The same degree of protection is obtained if the cooling is made in the presence of oxygen or under an air pressure of 1.25 atmosphere.