A. A. Markov's work on probability

Communicated by H. Freudenthal     

A non-linear combination of experts' forecasts: A Bayesian approach

A general Bayesian approach to combining n expert forecasts is developed. Under some moderate assumptions on the distributions of the expert errors, it leads to a consistent, monotonic, quasi-linear average formula. This generalizes Bordley's results.     

Isolation and structure of amplexoside A. A new glycoside fromAsclepias amplexicaulis

Résumé A partir de la racine d'Asclepias amplexicaulis on a isolé un nouveau glycoside de la série prégnane, avec une potentialité d'action anti-cancer. Il possède l'aglycone: 12-cinnamoyl-20-O-acétylsarcostine. Les sucres asclépobiose et digitoxose se trouvent á C-3.

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Part V of Plant Investigations. Part IV, seeD. M. Piatak andK. A. Reimann, Tetrahedron Lett.,1972, 4525; b) This work was supported by grants from the American Cancer Society (IC-26) and its Illinois Division (Seiffert Trust Fund).

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We gratefully acknowledge samples of asclepobiose and sarcostin from Prof.T. Reichstein and his workers.     

A propos d'antibiotiques insolubles

Summary The authors show the antibiotic activity of water-insoluble salts of hydrosoluble antibiotics in the case of penicillin G (salts of iron, copper, silver, gold, and uranium) and streptomycin (oleate).     

A cholinergic modulator.

Soluble proteins obtained from presynaptic cholinergic vesicles have been tested regarding their effects to modify postsynaptic spike generation. The results suggest that these proteins (or derivatives, incl. glycopeptides) may act as modulators in increasing the effectiveness and duration of postsynaptic spike generation. They may partake in generation of homosynaptic (posttetanic) potentiation.     

A new quinoline-carbamate aphicide

Summary We found that it was nearly impossible to apply the quinoline-carbamate aphicide per os by means of synthetic diets, owing to its high feeding-deterrent-effect. After application via the roots of the host plant, this systemic compound is deposited on the leaf surface. The results suggest that the toxic effect is not the result of the oral uptake of phloem sap, but of the tarsal contact with the toxicant. Sensitivity of aphids to this compound and LD₅₀-values were determined after topical applicationsWe are grateful to the Deutsche Forschungsgemeinschaft for offering a grant.Israel Institute for Biological Research, Ness-Ziona, visiting professor (Oct. 1974–Sep. 1975), Institut für Angewandte Zoologie der Universität Bonn (BRD).     

A microvolume molecular filter

A microvolume polymer membrane filter based on Amicon hollow fibers in described which permits separation of low molecular weight compounds from proteins, and can be used for desalting volumes of 100 microliter or less, or to separate cellular protein debris from perfusates during release studies. The filter has the advantage of being reusable and having almost no void volume.     

A synthetic cyclol tripeptide

Zusammenfassung Das dem-Methylalanyl--methylalanyl--methylalanin entsprechende Oxazolon (III) isomerisiert leicht zum kristallisierten Cyclol (IV), dessen Struktur sich aus dem Übergang in das Imidazolon (V) unter Wasserabspaltung ergibt.