Rational design of biosafe crop resistance to a range of nematodes using RNA interference

Double stranded RNA (dsRNA) molecules targeting two genes have been identified that suppress economically important parasitic nematode species of banana. Proteasomal Alpha Subunit 4 (pas-4) and Actin-4 (act-4) were identified from a survey of sequence databases and cloned sequences for genes conserved across four pests of banana, Radopholus similis, Pratylenchus coffeae, Meloidogyne incognita and Helicotylenchus multicinctus. These four species were targeted with dsRNAs containing exact 21 nucleotide matches to the conserved regions. Potential off-target effects were limited by comparison to Caenorhabditis, Drosophila, rat, rice and Arabidopsis genomes. In vitro act-4 dsRNA treatment of R. similis suppressed target gene expression by 2.3 fold, nematode locomotion by 66 ± 4% and nematode multiplication on carrot discs by 49 ± 5%. The best transgenic carrot hairy root lines expressing act-4 or pas-4 dsRNA reduced transcript message abundance of target genes in R. similis by 7.9 fold and 4 fold and nematode multiplication by 94 ± 2% and 69 ± 3%, respectively. The same act-4 and pas-4 lines reduced P. coffeae target transcripts by 1.7 and 2 fold and multiplication by 50 ± 6% and 73 ± 8%. Multiplication of M. incognita on the pas-4 lines was reduced by 97 ± 1% and 99 ± 1% while target transcript abundance was suppressed 4.9 and 5.6 fold. There was no detectable RNAi effect on non-target nematodes exposed to dsRNAs targeting parasitic nematodes. This work defines a framework for development of a range of non-protein defences to provide broad resistance to pests and pathogens of crops

Eureka and beyond: mining's impact on African urbanisation

This collection brings separate literatures on mining and urbanisation together at a time when both artisanal and large-scale mining are expanding in many African economies. While much has been written about contestation over land and mineral rights, the impact of mining on settlement, notably its catalytic and fluctuating effects on migration and urban growth, has been largely ignored. African nation-states’ urbanisation trends have shown considerable variation over the past half century. The current surge in ‘new’ mining countries and the slow-down in ‘old’ mining countries are generating some remarkable settlement patterns and welfare outcomes. Presently, the African continent is a laboratory of national mining experiences. This special issue on African mining and urbanisation encompasses a wide cross-section of country case studies: beginning with the historical experiences of mining in Southern Africa (South Africa, Zambia, Zimbabwe), followed by more recent mineralizing trends in comparatively new mineral-producing countries (Tanzania) and an established West African gold producer (Ghana), before turning to the influence of conflict minerals (Angola, the Democratic Republic of Congo and Sierra Leone)

The NuSTAR Extragalactic Survey: A First Sensitive Look at the High-energy Cosmic X-Ray Background Population

We report on the first 10 identifications of sources serendipitously detected by the Nuclear Spectroscopic Telescope Array (NuSTAR) to provide the first sensitive census of the cosmic X-ray background source population at gsim 10 keV. We find that these NuSTAR-detected sources are ≈100 times fainter than those previously detected at gsim 10 keV and have a broad range in redshift and luminosity (z = 0.020-2.923 and L 10-40 keV ≈ 4 × 1041-5 × 1045 erg s–1); the median redshift and luminosity are z ≈ 0.7 and L 10-40 keV ≈ 3 × 1044 erg s–1, respectively. We characterize these sources on the basis of broad-band ≈0.5-32 keV spectroscopy, optical spectroscopy, and broad-band ultraviolet-to-mid-infrared spectral energy distribution analyses. We find that the dominant source population is quasars with L 10-40 keV > 1044 erg s–1, of which ≈50% are obscured with N H gsim 1022 cm–2. However, none of the 10 NuSTAR sources are Compton thick (N H gsim 1024 cm–2) and we place a 90% confidence upper limit on the fraction of Compton-thick quasars (L 10-40 keV > 1044 erg s–1) selected at gsim 10 keV of lsim 33% over the redshift range z = 0.5-1.1. We jointly fitted the rest-frame ≈10-40 keV data for all of the non-beamed sources with L 10-40 keV > 1043 erg s–1 to constrain the average strength of reflection; we find R < 1.4 for Γ = 1.8, broadly consistent with that found for local active galactic nuclei (AGNs) observed at gsim 10 keV. We also constrain the host-galaxy masses and find a median stellar mass of ≈1011 M ☉, a factor ≈5 times higher than the median stellar mass of nearby high-energy selected AGNs, which may be at least partially driven by the order of magnitude higher X-ray luminosities of the NuSTAR sources. Within the low source-statistic limitations of our study, our results suggest that the overall properties of the NuSTAR sources are broadly similar to those of nearby high-energy selected AGNs but scaled up in luminosity and mass

Tides in colliding galaxies

Long tails and streams of stars are the most noticeable upshots of galaxy collisions. Their origin as gravitational, tidal, disturbances has however been recognized only less than fifty years ago and more than ten years after their first observations. This Review describes how the idea of galactic tides emerged, in particular thanks to the advances in numerical simulations, from the first ones that included tens of particles to the most sophisticated ones with tens of millions of them and state-of-the-art hydrodynamical prescriptions. Theoretical aspects pertaining to the formation of tidal tails are then presented. The third part of the review turns to observations and underlines the need for collecting deep multi-wavelength data to tackle the variety of physical processes exhibited by collisional debris. Tidal tails are not just stellar structures, but turn out to contain all the components usually found in galactic disks, in particular atomic / molecular gas and dust. They host star-forming complexes and are able to form star-clusters or even second-generation dwarf galaxies. The final part of the review discusses what tidal tails can tell us (or not) about the structure and content of present-day galaxies, including their dark components, and explains how tidal tails may be used to probe the past evolution of galaxies and their mass assembly history. On-going deep wide-field surveys disclose many new low-surface brightness structures in the nearby Universe, offering great opportunities for attempting galactic archeology with tidal tails.Comment: 46 pages, 13 figures, Review to be published in "Tidal effects in Astronomy and Astrophysics", Lecture Notes in Physics. Comments are most welcom

Ground conditions in central Manchester and Salford : the use of the 3D geoscientific model as a basis for decision support in the built environment

In the urban environment, site investigation studies provide a wealth of information about the ground conditions of the shallow subsurface. However, from the developers’ perspective, there is generally little incentive to integrate this information beyond the boundaries of the development site. By taking a more holistic view and combining knowledge of the near-surface geology with information on former land use and the groundwater regime across a wider area, it is possible to predict geological scenarios that may better inform ground investigation and reclamation strategies. As part of its urban research programme, the British Geological Survey has integrated its data holdings across 75 km2 of central Manchester and Salford. The information has been used to develop an integrated 3D model of the shallow subsurface. By exporting the elements of the model to a Geographical Information System (GIS), there is the capability to produce on demand bespoke maps, crosssections and other visualisation aids, relevant to regional planning and site appraisal. The value of such a system is illustrated by reference to five topic areas (geology, geotechnical engineering, hydrogeology, geochemistry and land use). A series of thematic maps illustrates the range of outputs. The approach provides a means of identifying potential problems and opportunities at an early stage in any proposed development and, if implemented over a wider area, it could assist in designing site investigation strategies and reduce costs by ensuring a more focused approach to development planning

Integrating modelling of geoscience information to support sustainable urban planning

The provision of reliable and up-to-date geoscientific information for the urban environment has assumed increasing importance in recent years as legislative changes have forced developers, planning authorities and regulators to consider more fully the implications and impact on the environment of large-scale development initiatives. To comply with the principles of sustainable development, developers are increasingly required to demonstrate that proposals are based on the best possible scientific information and analysis of risk. Nowhere is this more relevant than in the context of urban regeneration, where planning policy guidance gives priority to re-use of previously developed (brownfield) land. In England, brownfield sites, suitable for re-development, cover an area equivalent to half the size of London

Geology of the Pattingham area 1:10 000 sheet SO 89 NW; part of 1:50 000 sheet 153 (Wolverhampton) and 167 (Dudley)

SIGLEAvailable from British Library Document Supply Centre-DSC:8714.105(98/54) / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Geology of the Dudley district : a brief explanation of the geological map sheet 167 Dudley

This Sheet Explanation provides a summary of the geology of the district covered by the geological 1:50 000 Series Sheet 167 Dudley published as a bedrock and superficial edition in 2012. T he district lies in the counties of Shropshire, Worcestershire, Staffordshire and the metropolitan district of the West Midlands. The main population centres are in the east of the district, within the Black Country conurbation that includes Bilston, Wednesbury, Sedgley, Tipton, Dudley, Brierley Hill, Kingswinford, Halesowen and Stourbridge. Scattered villages and the town of Bridgnorth lie in the west. The western and central parts of the district comprise mainly farmland and woodland, including the northern part of the Wyre Forest. The elevation of the district is typically in excess of 75 m above OD, with the highest point within the district, at 315 m above OD, in the Clent Hills in the south-east. The district is drained by the rivers Severn and Stour, which flow from north to south across the western and central parts of the district, respectively

The limestone and dolomite resources of the country north and west of Ashbourne, Derbyshire Description of 1/25.000 sheet SK 51 and parts of 04, 05 and 14

15.25LD:5776.72(IGS-MAR--129) / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo