6,327 research outputs found
How should fracking research be funded?
The use of hydraulic fracturing (‘fracking’) to extract oil or gas from shales is a subject of controversy. There are many scientific questions about the risks associated with the technique, and much research remains to be done. ReFINE (Researching Fracking In Europe) is a research consortium led by Newcastle University and Durham University in the UK, focusing on the environmental impacts of shale gas and oil exploitation using fracking methods. The project was established to answer questions raised by members of the public across Europe on the risks of fracking. It aims to inform the debate surrounding fracking by undertaking scientific research, which will be peer-reviewed and openly accessible. This case study discusses the structure of ReFINE and the issues associated with using funding from oil and gas companies to support the research
Star Formation in the Circumnuclear Environment of NGC1068
We present near-infrared emission line images of the circumnuclear ring in
NGC1068. We have measured the Br_gamma fluxes in a number of star forming
complexes and derived extinctions for each of these by comparison with H_alpha.
We investigate the star forming histories of these regions and find that a
short burst of star formation occured co-evally throughout the ring within the
last 30-40 Myr, and perhaps as recently as 4-7 Myr ago. The 1-0 S(1) flux and
S(1)/Br_gamma ratios indicate that as well as fluorescence, shock excited H_2
emission contributes to the total flux. There is excess H_2 flux to the
North-West where the ionisation cone crosses the ring, and we have shown it is
possible that the non-stellar continuum from the Seyfert nucleus which produces
the high excitation lines could also be causing fluorescence at the edges of
molecular clouds in the ring. The nuclear 1-0 S(1) is more extended than
previously realised but only along the bar's major axis, and we consider
mechanisms for its excitation.Comment: 10 pages, 4 figures, LaTeX (mn.sty & psfig.sty). Accepted for
publication in MNRA
Rapid Detection of Leishmania infantum Infection in Dogs: Comparative Study Using an Immunochromatographic Dipstick Test, Enzyme-Linked Immunosorbent Assay, and PCR
Current zoonotic visceral leishmaniasis (ZVL) control programs in Brazil include the culling of Leishmania infantum-infected reservoir dogs, a strategy that has failed to prevent a rise of canine and human ZVL cases over the past decade. One of the main reasons this strategy has failed is because of a long delay between sample collection, sample analysis, and control implementation. A rapid, sensitive, and specific diagnostic tool would be highly desirable, because it would allow control interventions to be implemented in situ. We compared an immunochromatographic dipstick test to enzyme-linked immunosorbent assay (ELISA) and PCR for detecting L. infantum infections in dogs from an area of ZVL endemicity in Brazil. The dipstick test was shown to have 61 to 75% specificity and 72 to 77% sensitivity, compared to 100% specificity for both ELISA and PCR and 71 to 88% and 51 to 64% sensitivity for ELISA and PCR, respectively. Of the field samples tested, 92 of 175 (53%), 65 of 175 (37%), and 47 of 175 (27%) were positive by dipstick, ELISA, and PCR, respectively. The positive and negative predictive values for the tested dipstick were 58 to 77% and 75%, respectively. Efforts should be made to develop a more specific dipstick test for diagnosis of leishmaniasis, because they may ultimately prove more cost-effective than currently used diagnostic tests when used in mass-screening surveys
The flow generated in a continuously stratified rotating fluid by the differential rotation of a plane horizontal disc
Results are presented from a modelling investigation into the response of a rotating, linearly stratified fluid to local forcing induced by a differentially rotating smooth, horizontal disc. Attention was directed at cases in which the disc forcing is relatively strong, with Rossby number ε = ω/2Ω of order 1 or greater; here ω and Ω are the disc and background rotation frequencies, respectively. The principal flow dynamics resulting in the mixing and deformation of the initially stable density distribution were identified as (i) shear-induced mixing due to the local increase in fluid vorticity above the disc and (ii) meridional circulations produced by Ekman processes and the constraint of the container sidewall. Laboratory experiments revealed the growth of a mixed layer adjacent to the disc and the subsequent development of layers within the mixed region. Furthermore, the experiments showed that, even at relatively large ε, Ekman processes associated with background rotation constituted the dominant mechanism controlling development and evolution of the primary interface between mixed and unmixed fluid regions. Theoretical, energy-based scalings are derived to describe the growth rate of the interfacial region for εgsimScript O(1) which are consistent with the ε → ∞ limit corresponding to the Ω = 0 case. These scalings are shown to describe well the development of the density field within the forced flow
Supernova enrichment and dynamical histories of solar-type stars in clusters
We use N-body simulations of star cluster evolution to explore the hypothesis
that short-lived radioactive isotopes found in meteorites, such as 26-Al, were
delivered to the Sun's protoplanetary disc from a supernova at the epoch of
Solar System formation. We cover a range of star cluster formation parameter
space and model both clusters with primordial substructure, and those with
smooth profiles. We also adopt different initial virial ratios - from cool,
collapsing clusters to warm, expanding associations. In each cluster we place
the same stellar population; the clusters each have 2100 stars, and contain one
massive 25M_Sun star which is expected to explode as a supernova at about
6.6Myr. We determine the number of Solar (G)-type stars that are within 0.1 -
0.3pc of the 25M_Sun star at the time of the supernova, which is the distance
required to enrich the protoplanetary disc with the 26-Al abundances found in
meteorites. We then determine how many of these G-dwarfs are unperturbed
`singletons'; stars which are never in close binaries, nor suffer sub-100au
encounters, and which also do not suffer strong dynamical perturbations.
The evolution of a suite of twenty initially identical clusters is highly
stochastic, with the supernova enriching over 10 G-dwarfs in some clusters, and
none at all in others. Typically only ~25 per cent of clusters contain
enriched, unperturbed singletons, and usually only 1 - 2 per cluster (from a
total of 96 G-dwarfs in each cluster). The initial conditions for star
formation do not strongly affect the results, although a higher fraction of
supervirial (expanding) clusters would contain enriched G-dwarfs if the
supernova occurred earlier than 6.6Myr. If we sum together simulations with
identical initial conditions, then ~1 per cent of all G-dwarfs in our
simulations are enriched, unperturbed singletons.Comment: 14 pages, 5 figures, accepted for publication in MNRA
Making asset investment decisions for wastewater systems that include sustainability
Effective integrated water management is a key component of the World Water Vision and the way in which aspirations for water equity may be realized. Part of the vision includes the promotion of sustainability of water systems and full accountability for their interaction with other urban systems. One major problem is that “sustainability” remains an elusive concept, although those involved with the provision of urban wastewater systems now recognize that decisions involving asset investment should use the “triple bottom line” approach to society, the economy, and the environment. The Sustainable Water Industry Asset Resource Decisions project has devised a flexible and adaptable framework of decision support processes that can be used to include the principles of sustainability more effectively. Decision mapping conducted at the outset of the project has shown that only a narrow range of criteria currently influence the outcome of asset investment decisions. This paper addresses the concepts of sustainability assessment and presents two case studies that illustrate how multicriteria decision support systems can enhance the assessment of the relative sustainability of a range of options when decisions are being made about wastewater asset investment
A national scale inventory of resource provision for biodiversity within domestic gardens
The human population is increasingly disconnected from nature due to urbanisation. To counteract this phenomenon, the UK government has been actively promoting wildlife gardening. However, the extent to which such activities are conducted and the level of resource provision for biodiversity (e.g., food and nesting sites) within domestic gardens remains poorly documented. Here we generate estimates for a selection of key resources provided within gardens at a national scale, using 12 survey datasets gathered across the UK. We estimate that 22.7 million households (87% of homes) have access to a garden. Average garden SiZe is 190 m(2), extrapolating to a total area of 432,924 ha. Although substantial, this coverage is still an order of magnitude less than that of statutory protected areas. Approximately 12.6 million (48%) households provide supplementary food for birds, 7.4 million of which specifically use bird feeders. Similarly, there are a minimum of 4.7 million nest boxes within gardens. These figures equate to one bird feeder for every nine potentially feeder-using birds in the UK, and at least one nest box for every six breeding pairs of cavity nesting birds. Gardens also contain 2.5-3.5 million ponds and 28.7 million trees, which is just under a quarter of all trees occurring outside woodlands. Ongoing urbanisation, characterised by increased housing densities, is inevitable throughout the UK and elsewhere. The important contribution domestic gardens make to the green space infrastructure in residential areas must be acknowledged, as their reduction will impact biodiversity conservation, ecosystem services, and the well-being of the human population
Methane hydrate recycling offshore of Mauritania probably after the last glacial maximum
To what extent methane liberated from marine hydrate will enter the ocean during a warmer world is unknown. Although methane release due to hydrate dissociation has been modelled, it is unclear whether or not methane will reach the seafloor during a warmer world and therefore contribute to oceanic and atmospheric budgets. Here we show, using a new three-dimensional (3-D) seismic dataset, that some hydrate deposits surround the gas chimneys passing through the HSZ. Bottom water warming since the last glacial maximum (LGM) is interpreted to cause hydrate dissociation but critically some of the released methane was not vented to the ocean. The released gas caused seal failure and free gas entered the hydrate stability zone (HSZ) through vertical gas chimneys to where new hydrate accumulations formed. This process is a new evidence for methane recycling and could account in part for the lack of methane in ice core records that cover warming events during the late Quaternary. This research provides new insight into how methane could be recycled rather than vented during a warmer world
Yersinia ruckeri isolates recovered from diseased Atlantic Salmon (Salmo salar) in Scotland are more diverse than those from Rainbow Trout (Oncorhynchus mykiss) and represent distinct subpopulations
Yersinia ruckeri is the etiological agent of enteric redmouth (ERM) disease of farmed salmonids. Enteric redmouth disease is traditionally associated with rainbow trout (Oncorhynchus mykiss, Walbaum), but its incidence in Atlantic salmon (Salmo salar) is increasing. Yersinia ruckeri isolates recovered from diseased Atlantic salmon have been poorly characterized, and very little is known about the relationship of the isolates associated with these two species. Phenotypic approaches were used to characterize 109 Y. ruckeri isolates recovered over a 14-year period from infected Atlantic salmon in Scotland; 26 isolates from infected rainbow trout were also characterized. Biotyping, serotyping, and comparison of outer membrane protein profiles identified 19 Y. ruckeri clones associated with Atlantic salmon but only five associated with rainbow trout; none of the Atlantic salmon clones occurred in rainbow trout and vice versa. These findings suggest that distinct subpopulations of Y. ruckeri are associated with each species. A new O serotype (designated O8) was identified in 56 biotype 1 Atlantic salmon isolates and was the most common serotype identified from 2006 to 2011 and in 2014, suggesting an increased prevalence during the time period sampled. Rainbow trout isolates were represented almost exclusively by the same biotype 2, serotype O1 clone that has been responsible for the majority of ERM outbreaks in this species within the United Kingdom since the 1980s. However, the identification of two biotype 2, serotype O8 isolates in rainbow trout suggests that vaccines containing serotypes O1 and O8 should be evaluated in both rainbow trout and Atlantic salmon for application in Scotland
- …