1,206 research outputs found
Schedule Synchronisation in public Transport by Tabu Search and Genetic Method
This paper concerns schedule synchronization problems in public transit networks. In particular, it consists of three main parts. In the first the subject area is introduced, the terms are defined and framework for optimal synchronization in the form of problem representation and formulation is proposed. The second part is devoted to transfer synchronization problem when passengers changing transit lines at transfer points. The intergrated Tabu Search and Genetic solution method is developed with respect to this specific problem. The third part deals with headways harmonization problem i.e. synchronization of different transit lines schedules on a common segments of routes. For the solution of this problem a new bilevel optimization method is proposed with zones harmonization at the bottom level and co-ordination of zones, by time buffers assigned to timing points, at the upper level. Finally, the synchronization problems are numerically illustrated by real-life examples of the public transport lines in Cracow
Entrapment of Bacteria in Fluid Inclusions in Laboratory-Grown Halite
This is the publisher's version, also available electronically from "http://online.liebertpub.com".Cells of the bacterium Pseudomonas aeruginosa, which were genetically modified to produce green fluorescent protein, were entrapped in fluid inclusions in laboratory-grown halite. The bacteria were used to inoculate NaCl-saturated aqueous solutions, which were allowed to evaporate and precipitate halite. The number, size, and distribution of fluid inclusions were highly variable, but did not appear to be affected by the presence of the bacteria. Many of the inclusions in crystals from inoculated solutions contained cells in populations ranging from two to 20. Microbial attachment to crystal surfaces was neither evident nor necessary for entrapment. Cells occurred exclusively within fluid inclusions and were not present in the crystal matrix. In both the inclusions and the hypersaline solution, the cells fluoresced and twitched, which indicates that the bacteria might have remained viable after entrapment. The fluorescence continued up to 13 months after entrapment, which indicates that little degradation of the bacteria occurred over that time interval. The entrapment, fluorescence, and preservation of cells were independent of the volume of hypersaline solution used or whether the solutions were completely evaporated prior to crystal extraction. The results of this study have a wide range of implications for the long-term survival of microorganisms in fluid inclusions and their detection through petrography. The results also demonstrate the preservation potential for microbes in hypersaline fluid inclusions, which could allow cells to survive harsh conditions of space, the deep geologic past, or burial in sedimentary basins
Biological activities of alkaloids: From toxicology to pharmacology
Plants produce many secondary metabolites, which reveal biological activity [...]
Diversifying selection and host adaptation in two endosymbiont genomes
Background: The endosymbiont Wolbachia pipientis infects a broad range of arthropod and filarial nematode hosts. These diverse associations form an attractive model for understanding host: symbiont coevolution. Wolbachia's ubiquity and ability to dramatically alter host reproductive biology also form the foundation of research strategies aimed at controlling insect pests and vector-borne disease. The Wolbachia strains that infect nematodes are phylogenetically distinct, strictly vertically transmitted, and required by their hosts for growth and reproduction. Insects in contrast form more fluid associations with Wolbachia. In these taxa, host populations are most often polymorphic for infection, horizontal transmission occurs between distantly related hosts, and direct fitness effects on hosts are mild. Despite extensive interest in the Wolbachia system for many years, relatively little is known about the molecular mechanisms that mediate its varied interactions with different hosts. We have compared the genomes of the Wolbachia that infect Drosophila melanogaster, wMel and the nematode Brugia malayi, wBm to that of an outgroup Anaplasma marginale to identify genes that have experienced diversifying selection in the Wolbachia lineages. The goal of the study was to identify likely molecular mechanisms of the symbiosis and to understand the nature of the diverse association across different hosts. Results: The prevalence of selection was far greater in wMel than wBm. Genes contributing to DNA metabolism, cofactor biosynthesis, and secretion were positively selected in both lineages. In wMel there was a greater emphasis on DNA repair, cell division, protein stability, and cell envelope synthesis. Conclusion: Secretion pathways and outer surface protein encoding genes are highly affected by selection in keeping with host: parasite theory. If evidence of selection on various cofactor molecules reflects possible provisioning, then both insect as well as nematode Wolbachia may be providing substances to hosts. Selection on cell envelope synthesis, DNA replication and repair machinery, heat shock, and two component switching suggest strategies insect Wolbachia may employ to cope with diverse host and intra-host environments
An expressed sequence tag (EST) library for Drosophila serrata, a model system for sexual selection and climatic adaptation studies
The native Australian fly Drosophila serrata belongs to the highly speciose montium subgroup of the melanogaster species group. It has recently emerged as an excellent model system with which to address a number of important questions, including the evolution of traits under sexual selection and traits involved in climatic adaptation along latitudinal gradients. Understanding the molecular genetic basis of such traits has been limited by a lack of genomic resources for this species. Here, we present the first expressed sequence tag (EST) collection for D. serrata that will enable the identification of genes underlying sexually-selected phenotypes and physiological responses to environmental change and may help resolve controversial phylogenetic relationships within the montium subgroup
Identification of moisture transport mechanism in gypsum during convective drying
[EN] Gypsum is a popular building material. Drying and rewetting of gypsum is a process of practical importance. This work presents the experimental results of kinetic of drying, heating and internal pressure development in rewetted gypsum cylinders. Analysis of the observed changes is presented. Additionally sorption isotherms, permeability and dependence of Young’s modulus on moisture content were measured. These data will be used in the model of the process under development.Adamski, R.; Adamska, A.; Pakowski, Z. (2018). Identification of moisture transport mechanism in gypsum during convective drying. En IDS 2018. 21st International Drying Symposium Proceedings. Editorial Universitat Politècnica de València. 379-386. https://doi.org/10.4995/IDS2018.2018.7527OCS37938
Microbial identification for an effective biocleaning: the case study of the Santa Lucia alle Malve rupestrian church
Identifying the microbial community that lives on the lithic cultural heritage through phenotypic and genotypic approaches is fundamental for understanding the contribution of colonisers in biodeterioration and selecting the best cleaning solutions with environmentally-friendly products. This was done with the cultivable microbiota present on the internal walls of the Santa Lucia alle Malve (SLM) rock church, recognised by UNESCO as a World Heritage Site. The SLM church is in the Sasso Caveoso area (Matera, South Italy). It is fully excavated in the limestone rock. Numerous frescoes cover the internal surfaces, but the bacterial and fungal colonisation spoils its beauty. The results of this study clearly showed the predominance of bacteria of the phylum Firmicutes and precisely of the genus Bacillus, whose prevalence may be due to the specific environmental conditions, very similar in all sampling sites of the church, and to their ability to produce endospores. These dormant forms allow bacteria to survive in unfavourable conditions. The genotypic approach showed that the various Bacillus species isolated on the surfaces of the experimented church are closely related and similar but show a different phenotypic profile. This diversity of physiological and morphological traits reflects the potential complexity of the metabolomes present in the bacterial communities of the internal walls of the SLM and confirms the need to identify the colonisers correctly and proceed with a non-temporary bio-cleaning. The results of bio-cleaning using Solanum nigrum extracts were effective, but the durability of the treatment has yet to be verified
Microbial identification for an effective biocleaning: the case study of the Santa Lucia alle Malve rupestrian church
Identifying the microbial community that lives on the lithic cultural heritage through phenotypic and genotypic approaches is fundamental for understanding the contribution of colonisers in biodeterioration and selecting the best cleaning solutions with environmentally-friendly products. This was done with the cultivable microbiota present on the internal walls of the Santa Lucia alle Malve (SLM) rock church, recognised by UNESCO as a World Heritage Site. The SLM church is in the Sasso Caveoso area (Matera, South Italy). It is fully excavated in the limestone rock. Numerous frescoes cover the internal surfaces, but the bacterial and fungal colonisation spoils its beauty. The results of this study clearly showed the predominance of bacteria of the phylum Firmicutes and precisely of the genus Bacillus, whose prevalence may be due to the specific environmental conditions, very similar in all sampling sites of the church, and to their ability to produce endospores. These dormant forms allow bacteria to survive in unfavourable conditions. The genotypic approach showed that the various Bacillus species isolated on the surfaces of the experimented church are closely related and similar but show a different phenotypic profile. This diversity of physiological and morphological traits reflects the potential complexity of the metabolomes present in the bacterial communities of the internal walls of the SLM and confirms the need to identify the colonisers correctly and proceed with a non-temporary bio-cleaning. The results of bio-cleaning using Solanum nigrum extracts were effective, but the durability of the treatment has yet to be verified
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