931 research outputs found

    Opening the Rome-Southampton window for operator mixing matrices

    Full text link
    We show that the running of operators which mix under renormalization can be computed fully non-perturbatively as a product of continuum step scaling matrices. These step scaling matrices are obtained by taking the "ratio" of Z matrices computed at different energies in an RI-MOM type scheme for which twisted boundary conditions are an essential ingredient. Our method allows us to relax the bounds of the Rome-Southampton window. We also explain why such a method is important in view of the light quark physics program of the RBC-UKQCD collaborations. To illustrate our method, using n_f=2+1 domain-wall fermions, we compute the non-perturbative running matrix of four-quark operators needed in K->pipi decay and neutral kaon mixing. Our results are then compared to perturbation theory.Comment: 8 pages, 7 figures. v2: PRD version, minor changes and few references adde

    Evaluating the integrity of forested riparian buffers over a large area using LiDAR data and Google Earth Engine

    Get PDF
    Spatial and temporal changes in the land cover affect water quality in the streams and other water bodies. Stream riparian areas are increasingly relevant as the human modification of the landscape continue unabated. The objectives of this study were to: (1) determine the classes and the distribution of land cover in stream riparian areas; (2) examine the accuracy of the existing land cover data National Land Cover Database (NLCD) using high-resolution imagery NAIIP and LiDAR data; and (3) evaluate the integrity of forested riparian buffers areas in the Lower Savannah River basin. The land cover map was produced using a Support Vector Machine (SVM) algorithm supervised classification through the cloud-based Google Earth Engine platform with an overall accuracy assessment of 83.66%. LiDAR data analysis were implemented using ArcGIS 10.6. The result of this study demonstrates that LiDAR data can be used to accurately map the vegetation width, height and canopy cover within the riparian buffer over wide areas to support ecological-based management. It is also highlighted that the open-access imagery and the efficient geospatial analysis GEE provides a reliable methodology to remotely monitor forest cover and land use in the riparian buffer areas

    The K(ππ)I=2K\to(\pi\pi)_{I=2} Decay Amplitude from Lattice QCD

    Full text link
    We report on the first realistic \emph{ab initio} calculation of a hadronic weak decay, that of the amplitude A2A_2 for a kaon to decay into two \pi-mesons with isospin 2. We find ReA2=(1.436±0.063stat±0.258syst)108GeVA_2=(1.436\pm 0.063_{\textrm{stat}}\pm 0.258_{\textrm{syst}})\,10^{-8}\,\textrm{GeV} in good agreement with the experimental result and for the hitherto unknown imaginary part we find {Im}A2=(6.83±0.51stat±1.30syst)1013GeV\,A_2=-(6.83 \pm 0.51_{\textrm{stat}} \pm 1.30_{\textrm{syst}})\,10^{-13}\,{\rm GeV}. Moreover combining our result for Im\,A2A_2 with experimental values of Re\,A2A_2, Re\,A0A_0 and ϵ/ϵ\epsilon^\prime/\epsilon, we obtain the following value for the unknown ratio Im\,A0A_0/Re\,A0A_0 within the Standard Model: ImA0/ReA0=1.63(19)stat(20)syst×104\mathrm{Im}\,A_0/\mathrm{Re}\,A_0=-1.63(19)_{\mathrm{stat}}(20)_{\mathrm{syst}}\times10^{-4}. One consequence of these results is that the contribution from Im\,A2A_2 to the direct CP violation parameter ϵ\epsilon^{\prime} (the so-called Electroweak Penguin, EWP, contribution) is Re(ϵ/ϵ)EWP=(6.52±0.49stat±1.24syst)×104(\epsilon^\prime/\epsilon)_{\mathrm{EWP}} = -(6.52 \pm 0.49_{\textrm{stat}} \pm 1.24_{\textrm{syst}}) \times 10^{-4}. We explain why this calculation of A2A_2 represents a major milestone for lattice QCD and discuss the exciting prospects for a full quantitative understanding of CP-violation in kaon decays.Comment: 5 pages, 1 figur

    Lattice determination of the K(ππ)I=2K \to (\pi\pi)_{I=2} Decay Amplitude A2A_2

    Full text link
    We describe the computation of the amplitude A_2 for a kaon to decay into two pions with isospin I=2. The results presented in the letter Phys.Rev.Lett. 108 (2012) 141601 from an analysis of 63 gluon configurations are updated to 146 configurations giving ReA2=1.381(46)stat(258)syst108A_2=1.381(46)_{\textrm{stat}}(258)_{\textrm{syst}} 10^{-8} GeV and ImA2=6.54(46)stat(120)syst1013A_2=-6.54(46)_{\textrm{stat}}(120)_{\textrm{syst}}10^{-13} GeV. ReA2A_2 is in good agreement with the experimental result, whereas the value of ImA2A_2 was hitherto unknown. We are also working towards a direct computation of the K(ππ)I=0K\to(\pi\pi)_{I=0} amplitude A0A_0 but, within the standard model, our result for ImA2A_2 can be combined with the experimental results for ReA0A_0, ReA2A_2 and ϵ/ϵ\epsilon^\prime/\epsilon to give ImA0/A_0/ReA0=1.61(28)×104A_0= -1.61(28)\times 10^{-4} . Our result for Im\,A2A_2 implies that the electroweak penguin (EWP) contribution to ϵ/ϵ\epsilon^\prime/\epsilon is Re(ϵ/ϵ)EWP=(6.25±0.44stat±1.19syst)×104(\epsilon^\prime/\epsilon)_{\mathrm{EWP}} = -(6.25 \pm 0.44_{\textrm{stat}} \pm 1.19_{\textrm{syst}}) \times 10^{-4}.Comment: 59 pages, 11 figure

    Prioritization of fish communities with a view to conservation and restoration on a large scale European basin, the Loire (France)

    Get PDF
    The hierarchical organization of important sites for the conservation or the restoration of fish communities is a great challenge for managers, especially because of financial or time constraints. In this perspective, we developed a methodology, which is easy to implement in different locations. Based on the fish assemblage characteristics of the Loire basin (France), we created a synthetic conservation value index including the rarity, the conservation status and the species origin. The relationship between this new synthetic index and the Fish-Based Index allowed us to establish a classification protocol of the sites along the Loire including fish assemblages to be restored or conserved. Sites presenting disturbed fish assemblages, a low rarity index, few threatened species, and a high proportion of non-native species were considered as important for the restoration of fish biodiversity. These sites were found mainly in areas where the assemblages are typical of the bream zone, e.g. with a higher number of eurytopic and limnophilic species. On the contrary, important sites for conservation were defined as having an important conservation potential (high RI, a lot of threatened species, and few nonnatives fish species) and an undisturbed fish assemblage similar to the expected community if habitats are undisturbed. Important sites for conservation were found in the Loire basin’s medium reaches which host assemblages typical for the grayling and the barbell zones, e.g. with a higher number of rheophilic species. The synthetic conservation value index could be adapted and completed with other criteria according to management priorities and capacities

    Phosphorylation and Transport in the Na-K-2Cl Cotransporters, NKCC1 and NKCC2A, Compared in HEK-293 Cells

    Get PDF
    Na-K-2Cl cotransporters help determine cell composition and volume. NKCC1 is widely distributed whilst NKCC2 is only found in the kidney where it plays a vital role reabsorbing 20% of filtered NaCl. NKCC2 regulation is poorly understood because of its restricted distribution and difficulties with its expression in mammalian cell cultures. Here we compare phosphorylation of the N-termini of the cotransporters, measured with phospho-specific antibodies, with bumetanide-sensitive transport of K+ (86Rb+) (activity) in HEK-293 cells stably expressing fNKCC1 or fNKCC2A which were cloned from ferret kidney. Activities of transfected transporters were distinguished from those of endogenous ones by working at 37°C. fNKCC1 and fNKCC2A activities were highest after pre-incubation of cells in hypotonic low-[Cl−] media to reduce cell [Cl−] and volume during flux measurement. Phosphorylation of both transporters more than doubled. Pre-incubation with ouabain also strongly stimulated fNKCC1 and fNKCC2A and substantially increased phosphorylation, whereas pre-incubation in Na+-free media maximally stimulated fNKCC1 and doubled its phosphorylation, but inhibited fNKCC2A, with a small increase in its phosphorylation. Kinase inhibitors halved phosphorylation and activity of both transporters whereas inhibition of phosphatases with calyculin A strongly increased phosphorylation of both transporters but only slightly stimulated fNKCC1 and inhibited fNCCC2A. Thus kinase inhibition reduced phosphorylation and transport, and transport stimulation was only seen when phosphorylation increased, but transport did not always increase with phosphorylation. This suggests phosphorylation of the N-termini determines the transporters' potential capacity to move ions, but final activity also depends on other factors. Transport cannot be reliably inferred solely using phospho-specific antibodies on whole-cell lysates

    A Transdisciplinary Approach to Determining the Provenience of a Distorted, Pre-Columbian Skull Recovered in Rural Idaho

    Get PDF
    Transdisciplinary research involves cooperation, exchange of information, sharing of resources and integration of disciplines to achieve a common scientific goal. In this study, collaborators utilized tools and knowledge of materials science, anthropology, archaeology, geosciences and biology in an attempt to determine the provenience of skeletal remains of unknown origin. The exchange of ideas and skills along with the crossing of disciplines in this study sucessfully allowed the incorporation of expertise from many team members. This transdisciplinary approach to research provided a more comprehensive and detailed analysis than any one field alone could provide. An archaeological assessment of a human skull recovered in rural Idaho recognized cranial deformation and post-mortem application of a red pigment. A combination of scanning electron microscopy (SEM), x-ray fluorescence (XRF) and energy-dispersive x-ray spectroscopy (EDS) identified the major and trace elements present in the red post-mortem pigment as cinnabar and rare earth metals. Analysis via carbon and oxygen stable isotopes from teeth and bone to provided insight into the diet and habitat for distinct segments of the individual’s life, indicating a regional separation in early life versus late adulthood. Radiocarbon dating determined the approximate age of the skull to be between 600-700 years old and a forensic mtDNA assessmentcategorized a mitochondrial haplogroup for the remains as originating from the East African or Arabian Peninsula

    Multilevel Interventions Targeting Obesity: Research Recommendations for Vulnerable Populations

    Get PDF
    The origins of obesity are complex and multifaceted. To be successful, an intervention aiming to prevent or treat obesity may need to address multiple layers of biological, social, and environmental influences

    HCV IRES manipulates the ribosome to promote the switch from translation initiation to elongation.

    Get PDF
    The internal ribosome entry site (IRES) of the hepatitis C virus (HCV) drives noncanonical initiation of protein synthesis necessary for viral replication. Functional studies of the HCV IRES have focused on 80S ribosome formation but have not explored its role after the 80S ribosome is poised at the start codon. Here, we report that mutations of an IRES domain that docks in the 40S subunit's decoding groove cause only a local perturbation in IRES structure and result in conformational changes in the IRES-rabbit 40S subunit complex. Functionally, the mutations decrease IRES activity by inhibiting the first ribosomal translocation event, and modeling results suggest that this effect occurs through an interaction with a single ribosomal protein. The ability of the HCV IRES to manipulate the ribosome provides insight into how the ribosome's structure and function can be altered by bound RNAs, including those derived from cellular invaders
    corecore