ДОПОМОГА ООН У ПОДОЛАННІ НАСЛІДКІВ ЧОРНОБИЛЬСЬКОЇ КАТАСТРОФИ

The article has the analysis of problems threats faced after the Chernobyl accident; a lot of attention on the need to bring opportunities to the whole international organizations to use joint efforts to implement measures aimed at preventing the possibility of occurrence global consequence that their society has undergone as a result of that accident.

Four-valued modal logic: Kripke semantics and duality

Along the lines of recent investigations combining many-valued and modal systems, we address the problem of defining and axiomatizing the least modal logic over the four-element Belnap lattice. By this we mean the logic determined by the class of all Kripke frames where the accessibility relation as well as semantic valuations are four-valued. Our main result is the introduction of two Hilbert-style calculi that provide complete axiomatizations for, respectively, the local and the global consequence relations associated to the class of all four-valued Kripke models. Our completeness proofs make an extensive and profitable use of algebraic and topological techniques; in fact, our algebraic and topological analyses of the logic have, in our opinion, an independent interest and contribute to the appeal of our approach.

Overproduction of the MtrCDE Efflux Pump in Neisseria gonorrhoeae Produces Unexpected Changes in Cellular Transcription Patterns

ABSTRACTThe global consequence of drug efflux gene overexpression in bacteria has not been specifically analyzed because strains showing high-level expression typically have mutations in genes encoding regulatory proteins that control other genes. Results from a transcriptional profiling study performed with a strain ofNeisseria gonorrhoeaethat is capable of high-level transcription of themtrCDEefflux pump operon independently of control by cognate regulatory proteins revealed that its overexpression has ramifications for systems other than drug efflux.

Canonical rules

We develop canonical rules capable of axiomatizing all systems of multiple-conclusion rules over K4 or IPC, by extension of the method of canonical formulas by Zakharyaschev [37]. We use the framework to give an alternative proof of the known analysis of admissible rules in basic transitive logics, which additionally yields the following dichotomy: any canonical rule is either admissible in the logic, or it is equivalent to an assumption-free rule. Other applications of canonical rules include a generalization of the Blok–Esakia theorem and the theory of modal companions to systems of multiple-conclusion rules or (unitary structural global) consequence relations, and a characterization of splittings in the lattices of consequence relations over monomodal or superintuitionistic logics with the finite model property.

The Global Consequence of Disruption of the AcrAB-TolC Efflux Pump in Salmonella enterica Includes Reduced Expression of SPI-1 and Other Attributes Required To Infect the Host

ABSTRACT The mechanisms by which RND pumps contribute to pathogenicity are currently not understood. Using the AcrAB-TolC system as a paradigm multidrug-resistant efflux pump and Salmonella enterica serovar Typhimurium as a model pathogen, we have demonstrated that AcrA, AcrB, and TolC are each required for efficient adhesion to and invasion of epithelial cells and macrophages by Salmonella in vitro. In addition, AcrB and TolC are necessary for Salmonella to colonize poultry. Mutants lacking acrA, acrB, or tolC showed differential expression of major operons and proteins involved in pathogenesis. These included chemotaxis and motility genes, including cheWY and flgLMK and 14 Salmonella pathogenicity island (SPI)-1-encoded type III secretion system genes, including sopE, and associated effector proteins. Reverse transcription-PCR confirmed these data for identical mutants in two other S. Typhimurium backgrounds. Western blotting showed reduced production of SipA, SipB, and SipC. The absence of AcrB or TolC also caused widespread repression of chemotaxis and motility genes in these mutants, and for acrB::aph, this was associated with decreased motility. For mutants lacking a functional acrA or acrB gene, the nap and nir operons were repressed, and both mutants grew poorly in anaerobic conditions. All phenotypes were restored to that of the wild type by trans-complementation with the wild-type allele of the respective inactivated gene. These data explain how mutants lacking a component of AcrAB-TolC are attenuated and that this phenotype is a result of decreased expression of numerous genes encoding proteins involved in pathogenicity. The link between antibiotic resistance and pathogenicity establishes the AcrAB-TolC system as fundamental to the biology of Salmonella.

Foreign Capital, Local Interests and Railway Development in Argentina: French Investments in Railways, 1900–1914

Between 1900 and 1914, Argentina experienced the period of greatest growth of its railway network (see Fig. 1). During this time its total length was increased by about 12,000 miles, thus improving on the increase achieved during the railway boom of the 1880s. As before, the new peak was associated with a massive inflow of foreign capital which reached record levels: about 2,000 million gold pesos, against 800 millions during the 1880s. Furthermore, the new railway constructions were mainly made after 1907 and located in the pampas (see Tables 1 and 2). This rapid growth has been explained by many authors mainly as a global consequence of the so-called Mitre law (national law 5315), sanctioned in 1907, which standardised railway legislation in a way that favoured foreign investors, giving rise to an investment boom, especially among the British groups settled in the pampas.1