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The popularity of non-mechanically agitated flotation machines (flotation columns) has varied significantly over the last fifty years. There are various philosophies on the use of column flotation. These range from support of the concept of all column flotation plants, to the opposite extreme where the risks are considered to outweigh any potential gains of column flotation. The majority of mineral processing engineers support the installation of columns based on a logical appraisal. In the Australian coal industry, where flotation columns have almost total dominance, the use of anything other than a column would be questioned. Column flotation is also largely the dominant flotation technology in the coal industry in the USA and China, the phosphate industry in the USA and Brazil and the iron ore industry in Brazil. These areas of dominance represent a substantial installed column capacity, but even so are restricted to specific geographic areas and commodities. Within the base metals industry flotation columns are generally accepted in the smaller capacity cleaner roles worldwide. It should be noted that a number of flotation column installations have been dismal failures, but they represent only a fraction of total column installed capacity. This paper provides an analysis of over 4000 installed flotation columns, contained in the Amec Foster Wheeler flotation database. Changing trends in column flotation use by type, commodity and geographical region are reviewed. The reasons for the numerous rises and falls in column flotation use are also discussed.

The radiographic imaging of ancient Egyptian mummies has always been of great interest. Computed tomography is the method of choice to demonstrate bony pathologies with high quality. As digital volume tomography (DVT) is an extension of panoramic tomography with a very high resolution, its qualities were evaluated by examination of temporal bones of Egyptian mummy skulls. Ten Egyptian mummy skulls from the Zoological Collection Marburg, estimated 1,700-5,000 years of age, from Abydos, Philae, Theben-West and Sakkarah, were examined by DVT (3D Accuitomo, Morita, Japan). Through a rotation 360° of the X-ray source around the region of interest, a cylinder of 3 × 4 cm was captured as a three-dimensional volume. The gained data were analyzed with the help of special software on a PC. The angles of the axial, coronal and sagittal sections were arbitrarily changed to represent single structures with high resolution of 0.125 mm to analyze specific anatomical structures. In all skulls, conditions of the temporal bone and its anatomical structures were evaluated and normal as well as pathological findings evaluated in detail. The analysis of special landmarks such as the ossicular chain, cochlea, external, and internal auditory canal, facial nerve canal, and semicircular canals showed an intact ossicular chain in six temporal bones, while only isolated and dislocated ossicles were found in eight temporal bones. Besides one dehiscence of the superior semicircular canal in one temporal bone which might have led to vertigo and deafness at lifetime, all other findings were normal. Fragments of foreign bodies additionally found in the labyrinth, external ear canal and intracranially were attributed to postmortem damage. Digital volume tomography extends the imaging possibilities of CT for paleoradiological evaluation of temporal bones. With its high resolution, geometric accuracy, reconstruction capabilities, rapidness, and comparably low costs, even small bony pathologies are precisely demonstrated in a limited area. Investigations of larger numbers of specimen might reveal further details of ancient history for further interdisciplinary investigation of anthropologists, Egyptiologists, otolaryngologists, and radiologists.

International audience; Plants generate effective responses to infection by recognizing both conserved and variable pathogen-encoded molecules. Pathogens deploy virulence effector proteins into host cells, where they interact physically with host proteins to modulate defense. We generated an interaction network of plant-pathogen effectors from two pathogens spanning the eukaryote-eubacteria divergence, three classes of Arabidopsis immune system proteins, and similar to 8000 other Arabidopsis proteins. We noted convergence of effectors onto highly interconnected host proteins and indirect, rather than direct, connections between effectors and plant immune receptors. We demonstrated plant immune system functions for 15 of 17 tested host proteins that interact with effectors from both pathogens. Thus, pathogens from different kingdoms deploy independently evolved virulence proteins that interact with a limited set of highly connected cellular hubs to facilitate their diverse life-cycle strategies.

It has been observed in several Jameson cell installation where the source for flotation feed is deslime screens, that the recovery of coal particles greater than 0.5 mm is not as great as that of finer material. Consequently, a research project was undertaken at a CHPP in the Bowen Basin Queensland to assess the possibility of increasing the recovery of coarser particles (+0.5 mm) within the downcomer of the Jameson cell. The effect of decreasing turbulence and agitation in a commercial-scale downcomer was investigated to assess the effect on the recovery of both coarse and fine coal particles. This paper details the findings of the test work, summarising the results relating to differences in the operating parameters within the downcomer.

Since the invention of the Jameson cell in 1986 various mechanisms have been postulated for particle collection within the cell's downcomer. Possible mechanisms include thin film migration, instantaneous collection, mixing zone collection, residence time dependence and bubble surface area flux. The limited amount of investigation to date has not provided sufficient evidence to allow one mechanism to be supported over the others. A summary of the postulated mechanisms is presented along with the background to their formulation. They are assessed on the basis of available knowledge and categorized according to specific operating parameters within the Jameson cell downcomer. In addition, relationships between operating variables and various hydrodynamic zones within the downcomer are discussed. A review of how these mechanisms relate to flotation operations is conducted for coal flotation, base-metal ore flotation and the removal of organic matter from solution.

Soil-dwelling microbes are the principal inoculum for the root microbiota, but our understanding of microbe–microbe interactions in microbiota establishment remains fragmentary. We tested 39,204 binary interbacterial interactions for inhibitory activities in vitro, allowing us to identify taxonomic signatures in bacterial inhibition profiles. Using genetic and metabolomic approaches, we identified the antimicrobial 2,4-diacetylphloroglucinol (DAPG) and the iron chelator pyoverdine as exometabolites whose combined functions explain most of the inhibitory activity of the strongly antagonistic Pseudomonas brassicacearum R401. Microbiota reconstitution with a core of Arabidopsis thaliana root commensals in the presence of wild-type or mutant strains revealed a root niche-specific cofunction of these exometabolites as root competence determinants and drivers of predictable changes in the root-associated community. In natural environments, both the corresponding biosynthetic operons are enriched in roots, a pattern likely linked to their role as iron sinks, indicating that these cofunctioning exometabolites are adaptive traits contributing to pseudomonad pervasiveness throughout the root microbiota.