931 research outputs found
Opening the Rome-Southampton window for operator mixing matrices
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
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Evaluating the integrity of forested riparian buffers over a large area using LiDAR data and Google Earth Engine
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 Decay Amplitude from Lattice QCD
We report on the first realistic \emph{ab initio} calculation of a hadronic
weak decay, that of the amplitude for a kaon to decay into two \pi-mesons
with isospin 2. We find Re in good agreement with the
experimental result and for the hitherto unknown imaginary part we find
{Im}. Moreover combining our result for
Im\, with experimental values of Re\,, Re\, and
, we obtain the following value for the unknown ratio
Im\,/Re\, within the Standard Model:
.
One consequence of these results is that the contribution from Im\, to the
direct CP violation parameter (the so-called Electroweak
Penguin, EWP, contribution) is Re. We
explain why this calculation of 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 Decay Amplitude
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 Re GeV and Im
GeV. Re is in good agreement with the experimental result, whereas the
value of Im was hitherto unknown. We are also working towards a direct
computation of the amplitude but, within the
standard model, our result for Im can be combined with the experimental
results for Re, Re and to give
ImRe . Our result for Im\, implies
that the electroweak penguin (EWP) contribution to
is Re.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)
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
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Targeting LIF-mediated paracrine interaction for pancreatic cancer therapy and monitoring.
Pancreatic ductal adenocarcinoma (PDAC) has a dismal prognosis largely owing to inefficient diagnosis and tenacious drug resistance. Activation of pancreatic stellate cells (PSCs) and consequent development of dense stroma are prominent features accounting for this aggressive biology1,2. The reciprocal interplay between PSCs and pancreatic cancer cells (PCCs) not only enhances tumour progression and metastasis but also sustains their own activation, facilitating a vicious cycle to exacerbate tumorigenesis and drug resistance3-7. Furthermore, PSC activation occurs very early during PDAC tumorigenesis8-10, and activated PSCs comprise a substantial fraction of the tumour mass, providing a rich source of readily detectable factors. Therefore, we hypothesized that the communication between PSCs and PCCs could be an exploitable target to develop effective strategies for PDAC therapy and diagnosis. Here, starting with a systematic proteomic investigation of secreted disease mediators and underlying molecular mechanisms, we reveal that leukaemia inhibitory factor (LIF) is a key paracrine factor from activated PSCs acting on cancer cells. Both pharmacologic LIF blockade and genetic Lifr deletion markedly slow tumour progression and augment the efficacy of chemotherapy to prolong survival of PDAC mouse models, mainly by modulating cancer cell differentiation and epithelial-mesenchymal transition status. Moreover, in both mouse models and human PDAC, aberrant production of LIF in the pancreas is restricted to pathological conditions and correlates with PDAC pathogenesis, and changes in the levels of circulating LIF correlate well with tumour response to therapy. Collectively, these findings reveal a function of LIF in PDAC tumorigenesis, and suggest its translational potential as an attractive therapeutic target and circulating marker. Our studies underscore how a better understanding of cell-cell communication within the tumour microenvironment can suggest novel strategies for cancer therapy
Phosphorylation and Transport in the Na-K-2Cl Cotransporters, NKCC1 and NKCC2A, Compared in HEK-293 Cells
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
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
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.
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
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