Jan Zahálka

Learn More
The present overview covers various aspects of research going on in the Cannabis field in the Department of Natural Products at the Hebrew University. In the first part we discuss, and try to explain, the reason for the absence of the term Cannabis (and possibly also opium) in the Old Testament. In the second part we bring evidence that, contrary to widely(More)
The cannabimimetic activity of the two enantiomers of 11-hydroxy-delta-8-tetrahydrocannabinol (11-OH-delta-8-THC) was evaluated in pigeons trained to discriminate between the presence and absence of (-)-delta-9-tetrahydrocannabinol [(-)-delta-9-THC]. (-)-11-OH-Delta-8-THC exhibited cannabimimetic activity with a potency (ED50, 0.17 mg/kg) similar to that of(More)
The separation of six pairs of chiral cannabinoids was achieved using a dimethylphenylcarbamate derivative of amylose, immobilized on silica gel (ChiralPak AD, Daicel), using 2-propanol and ethanol as the modifiers of n-hexane in the mobile phase. Good separation was achieved for most of the solutes in both solvent systems under various conditions. The(More)
The size and importance of visual multimedia collections grew rapidly over the last years, creating a need for sophisticated multimedia analytics systems enabling large-scale, interactive, and insightful analysis. These systems need to integrate the human’s natural expertise in analyzing multimedia with the machine’s ability to process large-scale data. The(More)
The goal of our work is to integrate conventional mRNA expression profiles with miRNA expressions using the knowledge of their validated or predicted interactions in order to improve class prediction in genetically determined diseases. The raw mRNA and miRNA expression features become enriched or replaced by new aggregated features that model the mRNA-miRNA(More)
In this paper we propose <i>New Yorker Melange</i>, an interactive city explorer, which navigates New York venues through the eyes of New Yorkers having a similar taste to the interacting user. To gain insight into New Yorkers' preferences and properties of the venues, a dataset of more than a million venue images and associated annotations has been(More)
This paper presents Blackthorn, an efficient interactive multimodal learning approach facilitating analysis of multimedia collections of 100 million items on a single high-end workstation. This is achieved by efficient data compression and optimizations to the interactive learning process. The compressed i-I64 data representation costs tens of bytes per(More)
A widely persisting interpretation of Occam’s razor is that given two classifiers with the same training error, the simpler classifier is more likely to generalize better. Within a long-lasting debate in the machine learning community over Occam’s razor, Domingos (Data Min. Knowl. Discov. 3:409–425, 1999) rejects this interpretation and proposes that model(More)