272 research outputs found
Groundwater : meltwater interaction in a proglacial aquifer
Groundwater plays a significant role in the hydrology of active glacial catchments, with evidence that it may buffer changes in meltwater river flow and partially compensate for glacial loss. However, to date there has been little direct research into the hydrogeology and groundwater dynamics of proglacial aquifers. Here we directly investigate the three dimensional nature of a proglacial sandur (floodplain) aquifer in SE Iceland, using hydrogeological, geophysical, hydrological and stable isotopic techniques, and provide evidence of groundwater-melt water dynamics over three years.
We show that the proglacial sandur forms a thick (at least 50-100 m), high permeability (transmissivity up to 2500 m2/day) aquifer, extending over an area of approximately 6 km2. At least 35 million m3 of groundwater is stored in the aquifer, equivalent to ~23-28% of total annual river flow through the catchment. The volume of mean annual groundwater flow through the aquifer is at least 0.1-1 m3/sec, equivalent to ~10-20% of mean annual river flow. Groundwater across the aquifer is actively recharged from local precipitation and strongly influenced by individual rainfall events and seasonal precipitation. Glacial meltwater influence on groundwater also occurs in a zone extending from 20-500 m away from the meltwater river, for at least 3km down-sandur, and to at least 15 m deep. Within this zone summer recharge from the river to groundwater occurs when meltwater river flows are high, maintaining high summer groundwater levels compared to winter levels; and groundwater temperature and chemistry are strongly influenced by meltwater. Beyond this zone there is no substantial meltwater influence on groundwater.
From ~2 km down-sandur there is extensive groundwater discharge via springs, supporting semi-perennial streams that form distinct local ecosystems, and providing baseflow to the main meltwater river.
This research indicates that predicted continued climate change-related reductions in glacier coverage and increases in precipitation are likely to increase the significance of groundwater storage as a water resource, and of groundwater discharges in maintaining environmental river flows in glacier catchments
Novel imaging tools for investigating the role of immune signalling in the brain
Abstract not availableJonathan Henry W. Jacobsen, Lindsay M. Parker, Arun V. Everest-Dass, Erik P. Schartner, Georgios Tsiminis, Vasiliki Staikopoulos, Mark R. Hutchinson, Sanam Mustaf
On the Isomorphic Description of Chiral Symmetry Breaking by Non-Unitary Lie Groups
It is well-known that chiral symmetry breaking (SB) in QCD with
light quark flavours can be described by orthogonal groups as , due to local isomorphisms. Here we discuss the question how specific
this property is. We consider generalised forms of SB involving an
arbitrary number of light flavours of continuum or lattice fermions, in various
representations. We search systematically for isomorphic descriptions by
non-unitary, compact Lie groups. It turns out that there are a few alternative
options in terms of orthogonal groups, while we did not find any description
entirely based on symplectic or exceptional Lie groups. If we adapt such an
alternative as the symmetry breaking pattern for a generalised Higgs mechanism,
we may consider a Higgs particle composed of bound fermions and trace back the
mass generation to SB. In fact, some of the patterns that we encounter
appear in technicolour models. In particular if one observes a Higgs mechanism
that can be expressed in terms of orthogonal groups, we specify in which cases
it could also represent some kind of SB of techniquarks.Comment: 18 pages, to appear in Int. J. Mod. Phys.
Squirrelpox in a red squirrel in Fife
SQUIRRELPOX has been identified as a key factor in red squirrel (Sciurus vulgaris) decline in the UK.1 Grey squirrels (Sciurus carolinensis) are thought to act as reservoir hosts for squirrelpox virus (SQPV), the causative agent of squirrelpox, with a reported asymptomatic seroprevalence of 61 per cent.2SQPV is implicated in the complete replacement of red squirrels by grey squirrels throughout mainland England and Wales,1 and poses a major threat to Scottish red squirrel populations since being first detected in 2007.3 To combat this threat, an mortality surveillance programme has been established at the Royal (Dick) School of Veterinary Studies, University of Edinburgh, using opportunistic sampling of red squirrel carcases. This has been ongoing for several years, including a summary publication covering 262 cases submitted from 2005 to 2009.4As part of this monitoring programme, an adult female red squirrel carcase was submitted by a member of the public, after having been found in Townhall Wood (NT110894), on the outskirts of Dunfermline, Fife, in March 2024. Postmortem examination identified multiple lesions typically associated with squirrelpox, including ulcerative and exudative dermatitis of the periocular and perioral skin (Fig 1). Histopathology of the affected skin identified extensive ulceration alongside remnant areas of epithelium with marked ballooning degeneration and eosinophilic intracytoplasmic inclusion bodies. Transmission electron microscopy of the affected tissue also identified numerous pox virions within the affected tissue, which through their size, shape and available surface morphology (Fig 2), were consistent with those of SQPV. In Britain there have been no additional identified diseases in red squirrels that present with periocular or perioral, ulcerative to exudative dermatitis due to a poxvirus,5indicating this case is highly likely due to SQPV.This finding represents the first identification of squirrelpox north of the central belt and is consistent with the predictions of previous modelling, which identified a high risk of northern SQPV spread from 2023 onwards.6 This modelling also suggests a rapid increase and spread of squirrelpox into more northerly and naive red squirrel populations is likely following establishment north of the central belt in central Scotland.6This case and modelling supports an increased requirement for targeted investigations, ongoing monitoring and grey squirrel interventions both around Dunfermline itself and within adjacent areas to establish the disease burden in this locality and limit further northerly squirrelpox spread.LA Wilson, veterinary pathology lecturer, M Marr, postdoctoral research fellow, C Logie, postmortem room technician, K Beckmann, conservation medicine lecturer, PWW Lurz, squirrel ecologist, R Ogden, director of conservation science, E Milne, professor emerita of veterinary clinical pathology Royal (Dick) School of Veterinary Studies and Roslin Institute, University of Edinburgh, Easter Bush Campus, Roslin, Midlothian EH25 9RG email: [email protected] DJ Everest, pathology scientist APHA Weybridge, Addlestone, Surrey KT15 3NBReferences1 Tompkins DM, White AR, Boots M. Ecological replacement of native red squirrels by invasive greys driven by disease. Ecol Lett2003;6:189â962 Sainsbury AW, Nettleton P, Gilray J, et al. Grey squirrels have high seroprevalence to a parapoxvirus associated with deaths in red squirrels. Anim Conserv2000;3:229â33 3 Mclnnes CJ, Coulter L, Dagleish MP, et al. First cases of squirrelpox in red squirrels (Sciurus vulgaris) in Scotland. Vet Rec2009;164:528â314 LaRose JP, Meredith AL, Everest DJ, et al. Epidemiological and postmortem findings in 262 red squirrels (Sciurus vulgaris) in Scotland, 2005 to 2009. Vet Rec2010;167:297â3025 Everest DJ, Tolhurst-Cherriman DAR, Davies H, et al. Assessing a potential non-invasive method for viral diagnostic purposes in European squirrels. Hystrix 2019;30:44â506 White A, Lurz PWW. A modelling assessment of control strategies to prevent/reduce squirrelpox spread. 2014. Scottish Natural Heritage Commissioned Report No 627. https://bit.ly/441TOgM (accessed 8 April 2024)PROFESSIONHistory of the veterinary professionI WRITE in response to the debate article by Bruce Vivash Jones (VR, 16/23 March 2024, vol 194, p 236). As a PhD researcher on the history of the RCVS and veterinary regulation, and a veterinary nurse, I would like to raise some issues with Vivash Jonesâ historical evidence. He states that changes to the council structure would create an oligarchy. From his interpretation of an oligarchy I can assure him and our profession that the first RCVS council did work as This finding represents the first identification of squirrelpox north of the central belt20/27 April 2024 | VET RECORD312Fig 2: Squirrelpox virus virions detected in the affected tissue. Bar = 200 nmFig 1: Macroscopic lesions of ulcerative and exudative dermatitis surrounding the eye in a red squirrel (Sciurus vulgaris)Letters 20 April.indd 312Letters 20 April.indd 31216/04/2024 12:4816/04/2024 12:4
Emergent kinetic constraints, ergodicity breaking, and cooperative dynamics in noisy quantum systems
Kinetically constrained spin systems play an important role in understanding key properties of the dynamics of slowly relaxing materials, such as glasses. Recent experimental studies have revealed that manifest kinetic constraints govern the evolution of strongly interacting gases of highly excited atoms in a noisy environment. Motivated by this development we explore which types of kinetically constrained dynamics can generally emerge in quantum spin systems subject to strong noise and show how, in this framework, constraints are accompanied by conservation laws. We discuss an experimentally realizable case of a lattice gas, where the interplay between those and the geometry of the lattice leads to collective behavior and time-scale separation even at infinite temperature. This is in contrast to models of glass-forming substances which typically rely on low temperatures and the consequent suppression of thermal activation
Design and analysis of a fuel-efficient single-engine, turboprop-powered, business airplane
The speed, range, payload, and fuel efficiency of a general aviation airplane powered by one turboprop engine was determined and compared to a twin engine turboprop aircraft. An airplane configuration was developed which can carry six people for a noreserve range of 2,408 km at a cruise speed above 154 m/s, and a cruise altitude of about 9,144 m. The cruise speed is comparable to that of the fastest of the current twin turboprop powered airplanes. It is found that the airplane has a cruise specific range greater than all twin turboprop engine airplanes flying in its speed range and most twin piston engine airplanes flying at considerably slower cruise airspeeds
Comparative micro-epidemiology of pathogenic avian influenza virus outbreaks in a wild bird population
Understanding the epidemiological dynamics of highly pathogenic avian influenza virus (HPAIV) in wild birds is crucial for guiding effective surveillance and control measures. The spread of H5 HPAIV has been well characterized over large geographical and temporal scales. However, information about the detailed dynamics and demographics of individual outbreaks in wild birds is rare and important epidemiological parameters remain unknown. We present data from a wild population of long-lived birds (mute swans; Cygnus olor) that has experienced three outbreaks of related H5 HPAIVs in the past decade, specifically, H5N1 (2007), H5N8 (2016) and H5N6 (2017). Detailed demographic data were available and intense sampling was conducted before and after the outbreaks; hence the population is unusually suitable for exploring the natural epidemiology, evolution and ecology of HPAIV in wild birds. We show that key epidemiological features remain remarkably consistent across multiple outbreaks, including the timing of virus incursion and outbreak duration, and the presence of a strong age-structure in morbidity that likely arises from an equivalent age-structure in immunological responses. The predictability of these features across a series of outbreaks in a complex natural population is striking and contributes to our understanding of HPAIV in wild birds
Efficient Finite Groups Arising in the Study of Relative Asphericity
We study a class of two-generator two-relator groups, denoted Jn(m, k), that arise in the study of relative asphericity as groups satisfying a transitional curvature condition. Particular instances of these groups occur in the literature as finite groups of intriguing orders. Here we find infinite families of non-elementary virtually free groups and of finite metabelian non-nilpotent groups, for which we determine the orders. All Mersenne primes arise as factors of the orders of the non-metacyclic groups in the class, as do all primes from other conjecturally infinite families of primes. We classify the finite groups up to isomorphism and show that our class overlaps and extends a class of groups Fa,b,c with trivalent Cayley graphs that was introduced by C.M.Campbell, H.S.M.Coxeter, and E.F.Robertson. The theory of cyclically presented groups informs our methods and we extend part of this theory (namely, on connections with polynomial resultants) to ?bicyclically presented groups? that arise naturally in our analysis. As a corollary to our main results we obtain new infinite families of finite metacyclic generalized Fibonacci groups
Basic Atomic Physics
Contains reports on five research projects.Joint Services Electronics Program Contract DAAL03-92-C-0001Joint Services Electronics Program Grant DAAH04-95-1-0038National Science Foundation Grant PHY 92-21489U.S. Navy - Office of Naval Research Grant N00014-90-J-1322National Science Foundation Grant PHY 92-22768U.S. Army - Office of Scientific Research Grant DAAL03-92-G-0229U.S. Army - Office of Scientific Research Grant DAAL01-92-6-0197U.S. Navy - Office of Naval Research Grant N00014-89-J-1207Alfred P. Sloan FoundationU.S. Navy - Office of Naval Research Grant N00014-90-J-1642U.S. Navy - Office of Naval Research Grant N00014-94-1-080
Integrative omics identifies conserved and pathogen-specific responses of sepsis-causing bacteria
Even in the setting of optimal resuscitation in high-income countries severe sepsis and septic shock have a mortality of 20â40%, with antibiotic resistance dramatically increasing this mortality risk. To develop a reference dataset enabling the identification of common bacterial targets for therapeutic intervention, we applied a standardized genomic, transcriptomic, proteomic and metabolomic technological framework to multiple clinical isolates of four sepsis-causing pathogens: Escherichia coli, Klebsiella pneumoniae species complex, Staphylococcus aureus and Streptococcus pyogenes. Exposure to human serum generated a sepsis molecular signature containing global increases in fatty acid and lipid biosynthesis and metabolism, consistent with cell envelope remodelling and nutrient adaptation for osmoprotection. In addition, acquisition of cholesterol was identified across the bacterial species. This detailed reference dataset has been established as an open resource to support discovery and translational research
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