The paper analyzes Everett's interpretation of quantum mechanics in which every quantum measurement process results in a splitting of the actual world into a family of possible worlds. These worlds differ depending on the results of the measurement - in each of the worlds one of the possible particular outcomes takes place. The authors pose and discuss two problems: (i) to what extent can the measurement-created worlds be identified with the possible worlds of Lewis', and (ii) which system of modal logic is modeled by Everett's worlds. In contrast with Lewis' worlds, whose existence is limited only by consistency, Everett's universes are conditioned by past measurements. Moreover, they are 'genetically' interconnected by the fact that new worlds stem from their predecessors in which a particular measurement was performed. The type of modal logic that can describe the modalities in Everett's interpretation depends on the way in which we implement our intuitions concerning 'possibility' - as something that concerns the totality of possible situations in which we could have been now, if a particular sequence of measurements had taken place in the past - or, in a more temporal spirit, as a question about possible worlds in which we can find ourselves in the future.
The aim of this study was to optimize storage conditions of a microbial community used for degradation of petroleum-derived environmental contaminants. Microorganisms were either freeze-dried or directly frozen (-20°C) in the presence of four stabilizers: trehalose, sucrose, glycerol and DMSO. It was found that preincubation with trehalose and sucrose had a positive impact on cell viability for both tested storage techniques. Disaccharide-stabilized consortia were more biodiverse than control samples (untreated with any protectants) and they retained high xenobiotic biodegradation capabilities. The effect of glycerol and DMSO was unexpectedly poor, contradicting other findings on the protective action of these compounds on monocultures. Higher cell survival was achieved only upon short-term (7 days) freezing, whereas DMSO proved to be lethal in the case of freeze-dried communities. Taking into account practical and economic reasons, the use of sucrose rather than the more expensive trehalose appears as the most efficient method for microbial consortia biostabilization during long-term storage. The experimental work provides some important data concerning the problem of elaboration of improved methods for preserving robust microbial communities to be used in environmental biotechnology practice.