618 research outputs found

    Quantifying the effects of extreme events and oceanographic variability on the spatiotemporal biomass and distribution of two key euphausiid prey species

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    Euphausiids form a critical component of oceanic food chains and individual species vary in their responses to perturbation events. We aimed to establish if patterns of fine scale oceanographic variability and larger-scale climate events such as marine heatwaves (MHWs) could be linked with spring variability in the biomass of two key forage species in the northeast Pacific Ocean, Euphausia pacifica and Thysanoessa spinifera. To achieve this, we used long-term datasets from the west coast of Vancouver Island Canada, an important commercial fishing area, to first quantify interannual signals of variability in fine-scale oceanographic conditions using multivariate analysis. We then used geostatistical spatiotemporal modelling to quantify the effects on species-specific euphausiid biomass. Oceanographic data showed that the effects of warm events are not always observable, and effects vary across small spatial scales. Warming due to the 2014-2016 MHW was relatively mild on the continental shelf during spring (<1°C above climatology). Spring biomass of euphausiids, particularly E. pacifica, peaked in 2015, and all euphausiid groups analysed (E. pacifica, T. spinifera and total euphausiids) exhibited significant correlations with positive phases of the Pacific Decadal Oscillation. These results have implications for marine predators as euphausiids may act as system stabilisers in the northeast Pacific, thereby potentially increasing ecosystem resilience during extreme events

    Protocol for the ORION trial (RadiO fRequency ablatION for haemorrhoids): a randomised controlled trial

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    Background Haemorrhoids are common and can significantly impact the personal and working lives of individuals. Those with more severe symptoms and those not responding to conservative management may require surgery. Current surgical techniques are associated with a degree of postoperative discomfort which may delay return to normal activity. Recurrence is lower in more radical procedures but resulting pain is higher. Radiofrequency ablation (RFA) is a new technique that is gaining popularity and has several hypothesised benefits, including reduced pain and recurrence. However, available evidence is limited. A recent overview from the National Institute for Health and Clinical Excellence recommended more research, in the form of randomised controlled trials, be carried out before further investment is made by national health services. Our aim is to assess whether RFA is at least as good in terms of recurrence as existing surgical interventions, but superior in terms of pain, for patients with symptomatic grade II and III haemorrhoids. Methods The RadiO fRequency ablatION for haemorrhoids (ORION) trial will be a pragmatic multicentre patient/assessorblind parallel group-controlled trial with economic evaluation. The target sample size is 376 participants (188 per arm) and is based on two co-primary endpoints: (i) a non-inferiority design for recurrence and (ii) superiority design for pain at seven days. Participants with grade II or III haemorrhoids will be recruited in 16 National Health Service hospitals and randomised (1:1) to either RFA or surgeon’s choice of surgery. Conclusions Results will inform future practice for the treatment of grade II–III haemorrhoids and provide evidence for national health services on future investments in RFA

    Thermal and photochemical control of nitro-nitrito linkage isomerism in single-crystals of [Ni(medpt)(NO<sub>2</sub>)(η<sup>2</sup>-ONO)]

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    The known complex [Ni(medpt)(η1-NO2)(η2-ONO)] 1 (medpt = 3,3â€Č-diamino-N-methyldipropylamine) crystallises in the monoclinic space group P21/m with 1.5 molecules in the asymmetric unit with two different η1-NO2 ligand environments in the crystal structure. At 298 K the molecule (A) sitting in a general crystallographic site displays a mixture of isomers, 78% of the η1-NO2 isomer and 22% of an endo-nitrito–(η1-ONO) form. The molecule (B) sitting on a crystallographic mirror plane adopts the η1-NO2 isomeric form exclusively. However, a variable temperature crystallographic study showed that the two isomers were in equilibrium and upon cooling to 150 K the η1-ONO isomer converted completely to the η1-NO2 isomer, so that both independent molecules in the asymmetric unit were 100% in the η1-NO2 form. A kinetic analysis of the equilibrium afforded values of ΔH = −9.6 (±0.4) kJ mol−1, ΔS = −21.5 (±1.8) J K−1 mol−1 and EA = −1.6 (±0.05) kJ mol−1. Photoirradiation of single crystals of 1 with 400 nm light, at 100 K, resulted in partial isomerisation of the η1-NO2 isomer to the metastable η1-ONO isomer, with 89% for molecule (A), and 32% for molecule (B). The crystallographic space group also reduced in symmetry to P21 with Zâ€Č = 3. The metastable state existed up to a temperature of 150 K above which temperature it reverted to the ground state. An analysis of the crystal packing in the ground and metastable states suggests that hydrogen bonding is responsible for the difference in the conversion between molecules (A) and (B)

    CRAGE-Duet Facilitates Modular Assembly of Biological Systems for Studying Plant-Microbe Interactions

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    Developing sustainable agricultural practices will require increasing our understanding of plant-microbe interactions. To study these interactions, new genetic tools for manipulating nonmodel microbes will be needed. To help meet this need, we recently reported development of chassis-independent recombinase-assisted genome engineering (CRAGE). CRAGE relies on cassette exchange between two pairs of mutually exclusive lox sites and allows direct, single-step chromosomal integration of large, complex gene constructs into diverse bacterial species. We then extended CRAGE by introducing a third mutually exclusive lox site, creating CRAGE-Duet, which allows modular integration of two constructs. CRAGE-Duet offers advantages over CRAGE, especially when a cumbersome recloning step is required to build single-integration constructs. To demonstrate the utility of CRAGE-Duet, we created a set of strains from the plant-growth-promoting rhizobacterium Pseudomonas simiae WCS417r that expressed various fluorescence marker genes. We visualized these strains simultaneously under a confocal microscope, demonstrating the usefulness of CRAGE-Duet for creating biological systems to study plant-microbe interactions

    Discovery of distinct immune phenotypes using machine learning in pulmonary arterial hypertension

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    RATIONALE: Accumulating evidence implicates inflammation in pulmonary arterial hypertension (PAH) and therapies targeting immunity are under investigation, though it remains unknown if distinct immune phenotypes exist. OBJECTIVE: Identify PAH immune phenotypes based on unsupervised analysis of blood proteomic profiles. METHODS AND RESULTS: In a prospective observational study of Group 1 PAH patients evaluated at Stanford University (discovery cohort, n=281) and University of Sheffield (validation cohort, n=104) between 2008-2014, we measured a circulating proteomic panel of 48 cytokines, chemokines, and factors using multiplex immunoassay. Unsupervised machine learning (consensus clustering) was applied in both cohorts independently to classify patients into proteomic immune clusters, without guidance from clinical features. To identify central proteins in each cluster, we performed partial correlation network analysis. Clinical characteristics and outcomes were subsequently compared across clusters. Four PAH clusters with distinct proteomic immune profiles were identified in the discovery cohort. Cluster 2 (n=109) had low cytokine levels similar to controls. Other clusters had unique sets of upregulated proteins central to immune networks- cluster 1 (n=58)(TRAIL, CCL5, CCL7, CCL4, MIF), cluster 3 (n=77)(IL-12, IL-17, IL-10, IL-7, VEGF), and cluster 4 (n=37)(IL-8, IL-4, PDGF-ÎČ, IL-6, CCL11). Demographics, PAH etiologies, comorbidities, and medications were similar across clusters. Non-invasive and hemodynamic surrogates of clinical risk identified cluster 1 as high-risk and cluster 3 as low-risk groups. Five-year transplant-free survival rates were unfavorable for cluster 1 (47.6%, CI 35.4-64.1%) and favorable for cluster 3 (82.4%, CI 72.0-94.3%)(across-cluster p<0.001). Findings were replicated in the validation cohort, where machine learning classified four immune clusters with comparable proteomic, clinical, and prognostic features. CONCLUSIONS: Blood cytokine profiles distinguish PAH immune phenotypes with differing clinical risk that are independent of World Health Organization Group 1 subtypes. These phenotypes could inform mechanistic studies of disease pathobiology and provide a framework to examine patient responses to emerging therapies targeting immunity

    Photoproduction of D∗±D^{*\pm} mesons associated with a leading neutron

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    The photoproduction of D∗±(2010)D^{*\pm} (2010) mesons associated with a leading neutron has been observed with the ZEUS detector in epep collisions at HERA using an integrated luminosity of 80 pb−1^{-1}. The neutron carries a large fraction, {xL>0.2x_L>0.2}, of the incoming proton beam energy and is detected at very small production angles, {Ξn<0.8\theta_n<0.8 mrad}, an indication of peripheral scattering. The D∗D^* meson is centrally produced with pseudorapidity {∣η∣1.9|\eta| 1.9 GeV}, which is large compared to the average transverse momentum of the neutron of 0.22 GeV. The ratio of neutron-tagged to inclusive D∗D^* production is 8.85±0.93(stat.)−0.61+0.48(syst.)%8.85\pm 0.93({\rm stat.})^{+0.48}_{-0.61}({\rm syst.})\% in the photon-proton center-of-mass energy range {130<W<280130 <W<280 GeV}. The data suggest that the presence of a hard scale enhances the fraction of events with a leading neutron in the final state.Comment: 28 pages, 4 figures, 2 table

    Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

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    The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter

    Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS

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    We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutralino lifetime. Limits are presented for different squark and neutralino masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final version to appear in Physics Letters

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

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    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

    Reducing heterotic M-theory to five dimensional supergravity on a manifold with boundary

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    This paper constructs the reduction of heterotic MM-theory in eleven dimensions to a supergravity model on a manifold with boundary in five dimensions using a Calabi-Yau three-fold. New results are presented for the boundary terms in the action and for the boundary conditions on the bulk fields. Some general features of dualisation on a manifold with boundary are used to explain the origin of some topological terms in the action. The effect of gaugino condensation on the fermion boundary conditions leads to a `twist' in the chirality of the gravitino which can provide an uplifting mechanism in the vacuum energy to cancel the cosmological constant after moduli stabilisation.Comment: 16 pages, RevTe
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