4,899 research outputs found
Isolation by Distance Explains Genetic Structure of Buggy Creek Virus, a Bird-Associated Arbovirus
Many of the arthropod-borne viruses (arboviruses) show extensive genetic variability and are widely distributed over large geographic areas. Understanding how virus genetic structure varies in space may yield insight into how these pathogens are adapted to and dispersed by different hosts or vectors, the relative importance of mutation, drift, or selection in generating genetic variability, and where and when epidemics or epizootics are most likely to occur. However, because most arboviruses tend to be sampled opportunistically and often cannot be isolated in large numbers at a given locale, surprisingly little is known about their spatial genetic structure on the local scale at which host/vector/virus interactions typically occur. Here, we examine fine-scale spatial structure of two sympatric lineages of Buggy Creek virus (BCRV, Togaviridae), an alphavirus transmitted by the ectoparasitic swallow bug (Oeciacus vicarius) to colonially nesting cliff swallows (Petrochelidon pyrrhonota) and invasive house sparrows (Passer domesticus) in North America. Data from 377 BCRV isolates at cliff swallow colony sites in western Nebraska showed that both virus lineages were geographically structured. Most haplotypes were detected at a single colony or were shared among nearby colonies, and pair-wise genetic distance increased significantly with geographic distance between colony sites. Genetic structure of both lineages is consistent with isolation by distance. Sites with the most genetically distinct BCRV isolates were occupied by large numbers of house sparrows, suggesting that concentrations of invasive sparrows may represent foci for evolutionary change in BCRV. Our results show that bird-associated arboviruses can show genetic substructure over short geographic distances
Isolation by Distance Explains Genetic Structure of Buggy Creek Virus, a Bird-Associated Arbovirus
Many of the arthropod-borne viruses (arboviruses) show extensive genetic variability and are widely distributed over large geographic areas. Understanding how virus genetic structure varies in space may yield insight into how these pathogens are adapted to and dispersed by different hosts or vectors, the relative importance of mutation, drift, or selection in generating genetic variability, and where and when epidemics or epizootics are most likely to occur. However, because most arboviruses tend to be sampled opportunistically and often cannot be isolated in large numbers at a given locale, surprisingly little is known about their spatial genetic structure on the local scale at which host/vector/virus interactions typically occur. Here, we examine fine-scale spatial structure of two sympatric lineages of Buggy Creek virus (BCRV, Togaviridae), an alphavirus transmitted by the ectoparasitic swallow bug (Oeciacus vicarius) to colonially nesting cliff swallows (Petrochelidon pyrrhonota) and invasive house sparrows (Passer domesticus) in North America. Data from 377 BCRV isolates at cliff swallow colony sites in western Nebraska showed that both virus lineages were geographically structured. Most haplotypes were detected at a single colony or were shared among nearby colonies, and pair-wise genetic distance increased significantly with geographic distance between colony sites. Genetic structure of both lineages is consistent with isolation by distance. Sites with the most genetically distinct BCRV isolates were occupied by large numbers of house sparrows, suggesting that concentrations of invasive sparrows may represent foci for evolutionary change in BCRV. Our results show that bird-associated arboviruses can show genetic substructure over short geographic distances
SIMULATING MULTI-COMPONENT PARTICLES BEHAVIOUR DURING THE CLASSIFICATION PROCESS IN A HYDROCYCLONE USING MULTIPHASE CFD MODEL
Numerical simulation of the hydrocyclone is known for its complexity and non-trivial solving strategies. The flow inside the hydrocyclone is highly turbulent and intricate in nature. Most of the mathematical model reflects the single average mineral density for the hydrocyclone multiphase classification performance. The behaviour of multicomponent particles in a hydrocyclone is superficially understood and the component interactions are unaccounted for most of the available mathematical models .In this work, multi size and density simulation of hydrocyclone are carried out using CFD approach. The turbulence is solved using the large eddy simulation (LES) model. The multiphase is modelled using the volume of fluid (VOF) and algebraic slip mixture (ASM) model. The multi-phase numerical simulation contains 10 phases at an instant i.e. water, air, 4 phases of magnetite and silica each, having different sizes and volume fractions. The mixture of magnetite and silica ratios i.e. 1:9, 2:8, 1:1 is considered for the understanding of interaction between components and sizes in complex flow system at optimized hydrocyclone conditions. The CFD model is able to predict the salient features of the cyclone flow fields in great detail, thus providing a better understanding of the solid recovery to the underflow, where authors have observed high Rs for the heavier particle i.e. magnetite. Separation characteristics of the silica and magnetite particles are explained using locus of zero vertical velocities (LZVV) and equilibrium radius
Ecological divergence of two sympatric lineages of Buggy Creek virus, an arbovirus associated with birds
Most arthropod-borne viruses (arboviruses) show distinct serological subtypes or evolutionary lineages, with the evolution of different strains often assumed to reflect differences in ecological selection pressures. Buggy Creek virus (BCRV) is an unusual RNA virus (Togaviridae, Alphavirus) that is associated primarily with a cimicid swallow bug (Oeciacus vicarius) as its vector and the Cliff Swallow (Petrochelidon pyrrhonota) and the introduced House Sparrow (Passer domesticus) as its amplifying hosts. There are two sympatric lineages of BCRV (lineages A and B) that differ from each other by .6% at the nucleotide level. Analysis of 385 BCRV isolates all collected from bug vectors at a study site in southwestern Nebraska, USA, showed that the lineages differed in their peak times of seasonal occurrence within a summer. Lineage A was more likely to be found at recently established colonies, at those in culverts (rather than on highway bridges), and at those with invasive House Sparrows, and in bugs on the outsides of nests. Genetic diversity of lineage A increased with bird colony size and at sites with House Sparrows, while that of lineage B decreased with colony size and was unaffected by House Sparrows. Lineage A was more cytopathic on mammalian cells than was lineage B. These two lineages have apparently diverged in their transmission dynamics, with lineage A possibly more dependent on birds and lineage B perhaps more a bug virus. The long-standing association between Cliff Swallows and BCRV may have selected for immunological resistance to the virus by swallows and thus promoted the evolution of the more bug-adapted lineage B. In contrast, the recent arrival of the introduced House Sparrow and its high competence as a BCRV amplifying host may be favoring the more bird-dependent lineage A
Supersymmetry discovery potential of the LHC at 10 and 14 TeV without and with missing
We examine the supersymmetry (SUSY) reach of the CERN LHC operating at
and 14 TeV within the framework of the minimal supergravity
model. We improve upon previous reach projections by incorporating updated
background calculations including a variety of Standard Model (SM)
processes. We show that SUSY discovery is possible even before the detectors
are understood well enough to utilize either or electrons in
the signal. We evaluate the early SUSY reach of the LHC at TeV by
examining multi-muon plus jets and also dijet events with {\it no}
missing cuts and show that the greatest reach in terms of
occurs in the dijet channel. The reach in multi-muons is slightly smaller in
, but extends to higher values of . We find that an observable
multi-muon signal will first appear in the opposite-sign dimuon channel, but as
the integrated luminosity increases the relatively background-free but
rate-limited same-sign dimuon, and ultimately the trimuon channel yield the
highest reach. We show characteristic distributions in these channels that
serve to distinguish the signal from the SM background, and also help to
corroborate its SUSY origin. We then evaluate the LHC reach in various
no-lepton and multi-lepton plus jets channels {\it including} missing
cuts for and 14 TeV, and plot the reach for integrated
luminosities ranging up to 3000 fb at the SLHC. For TeV,
the LHC reach extends to and 2.9 TeV for
and integrated luminosities of 10, 100, 1000 and
3000 fb, respectively. For TeV, the LHC reach for the same
integrated luminosities is to m_{gluino}=2.4,\3.1, 3.7 and 4.0 TeV.Comment: 34 pages, 25 figures. Revised projections for the SUSY reach for
ab^-1 integrated luminosities, with minor corrections of references and text.
2 figures added. To appear in JHE
New Particles Working Group Report of the Snowmass 2013 Community Summer Study
This report summarizes the work of the Energy Frontier New Physics working
group of the 2013 Community Summer Study (Snowmass)
Winter Ecology of Buggy Creek Virus (Togaviridae, \u3ci\u3eAlphavirus\u3c/i\u3e) in the Central Great Plains
A largely unanswered question in the study of arboviruses is the extent to which virus can overwinter in adult vectors during the cold winter months and resume the transmission cycle in summer. Buggy Creek virus (BCRV; Togaviridae, Alphavirus) is an unusual arbovirus that is vectored primarily by the swallow bug (Hemiptera: Cimicidae: Oeciacus vicarius) and amplified by the ectoparasitic bug’s main avian hosts, the migratory cliff swallow (Petrochelidon pyrrhonota) and resident house sparrow (Passer domesticus). Bugs are sedentary and overwinter in the swallows’ mud nests. We evaluated the prevalence of BCRV and extent of infection in swallow bugs collected at different times in winter (October–early April) in Nebraska and explored other ecological aspects of this virus’s overwintering. BCRV was detected in 17% of bug pools sampled in winter. Virus prevalence in bugs in winter at a site was significantly correlated with virus prevalence at that site the previous summer, but winter prevalence did not predict BCRV prevalence there the following summer. Prevalence was higher in bugs taken from house sparrow nests in winter and (in April) at colony sites where sparrows had been present all winter. Virus detected by reverse transcription (RT)-polymerase chain reaction in winter was less cytopathic than in summer, but viral RNA concentrations of samples in winter were not significantly different from those in summer. Both of the BCRV lineages (A, B) overwintered successfully, with lineage A more common at sites with house sparrows and (in contrast to summer) generally more prevalent in winter than lineage B. BCRV’s ability to overwinter in its adult vector probably reflects its adaptation to the sedentary, long-lived bug and the ecology of the cliff swallow and swallow bug host–parasite system. Its overwintering mechanisms may provide insight into those of other alphaviruses of public health significance for which such mechanisms are poorly known
Trunk girdling increased stomatal conductance in Cabernet Sauvignon Grapevines, reduced glutamine, and increased malvidin-3-glucoside and quercetin-3-glucoside concentrations in skins and pulp at harvest.
Girdling is a traditional horticultural practice applied at fruit set or other phenological stages, and is used mostly as a vine management. In grapevines, it is used primarily for table grapes to improve berry weight, sugar content, color, and to promote early harvest. The objective of this study was to evaluate the effect of trunk girdling applied at veraison, in ?Cabernet Sauvignon? wine grapes (Vitis vinifera L.), on agronomical and physiological parameters during vine development from the onset of ripening (veraison) to harvest, and additionally to quantify the effect of girdling on primary and secondary metabolism. Girdling was applied 146 days after pruning (dap) at veraison, when berry sampling for metabolomics and agronomical evaluations commenced, with a further three sampling dates until harvest, at 156 dap (30% maturation, 10 days after girdling-dag), 181 dap (70% maturation, 35 dag), and 223 dap (commercial harvest, 77 dag). Skin/pulp and seed tissues were extracted separately and metabolomics was performed using one-dimensional proton nuclear magnetic resonance (1D 1H NMR) spectroscopy and high performance liquid chromatography (HPLC-DAD). At harvest, girdling significantly increased stomatal conductance (gs) in vines, decreased glutamine concentrations, and increased anthocyanin and flavonol concentrations in the skin/pulp tissues of grape berries. Berry weight was reduced by 27% from 181 dap to harvest, and was significantly higher in grapes from girdled vines at 181 dap. Sugars, organic acids, and other amino acids in skin/pulp or seeds were not significantly different, possibly due to extra-fascicular phloem vessels transporting metabolites from leaves to the roots. Using a metabolomics approach, differences between skin/pulp and seeds tissues were meaningful, and a greater number of secondary metabolites in skin/pulp was affected by girdling than in seeds. Girdling is a simple technique that could easily be applied commercially on vine management to improve berry color and other phenolics in ?Cabernet Sauvignon? grapes. Keywords: amino acids, biosynthesis, grape and wine, 1H NMR spectroscopy, metabolome, organic acids, phenolic compounds and sugars, Vitis vinifera L
Winter Ecology of Buggy Creek Virus (Togaviridae, \u3ci\u3eAlphavirus\u3c/i\u3e) in the Central Great Plains
A largely unanswered question in the study of arboviruses is the extent to which virus can overwinter in adult vectors during the cold winter months and resume the transmission cycle in summer. Buggy Creek virus (BCRV; Togaviridae, Alphavirus) is an unusual arbovirus that is vectored primarily by the swallow bug (Hemiptera: Cimicidae: Oeciacus vicarius) and amplified by the ectoparasitic bug’s main avian hosts, the migratory cliff swallow (Petrochelidon pyrrhonota) and resident house sparrow (Passer domesticus). Bugs are sedentary and overwinter in the swallows’ mud nests. We evaluated the prevalence of BCRV and extent of infection in swallow bugs collected at different times in winter (October–early April) in Nebraska and explored other ecological aspects of this virus’s overwintering. BCRV was detected in 17% of bug pools sampled in winter. Virus prevalence in bugs in winter at a site was significantly correlated with virus prevalence at that site the previous summer, but winter prevalence did not predict BCRV prevalence there the following summer. Prevalence was higher in bugs taken from house sparrow nests in winter and (in April) at colony sites where sparrows had been present all winter. Virus detected by reverse transcription (RT)-polymerase chain reaction in winter was less cytopathic than in summer, but viral RNA concentrations of samples in winter were not significantly different from those in summer. Both of the BCRV lineages (A, B) overwintered successfully, with lineage A more common at sites with house sparrows and (in contrast to summer) generally more prevalent in winter than lineage B. BCRV’s ability to overwinter in its adult vector probably reflects its adaptation to the sedentary, long-lived bug and the ecology of the cliff swallow and swallow bug host–parasite system. Its overwintering mechanisms may provide insight into those of other alphaviruses of public health significance for which such mechanisms are poorly known
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