3,548 research outputs found

    D<sub>s</sub> to φ and other transitions from lattice QCD

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    We have studied transitions between vector and pseudoscalar mesons using the HISQ action for the valence quarks. We have calculated all of the axial and vector form factors that appear in the decay rate for D_s -&gt; phi l nu over the full q^2 range and compared them to the shape of the experimental decay distributions. We use nonperturbatively normalised currents for the vector and axial vector currents. The same set up for the three point correlations functions also allow us to study radiative decays and we have calculated the decay rate for J/Psi -&gt; eta_c gamma

    Liposomes encapsulating polymeric chitosan based vesicles - a vesicle in vesicle system for drug delivery

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    Drug delivery systems comprising vesicles prepared from one amphiphile encapsulating vesicles prepared from a second amphiphile have not been prepared previously due to a tendency of the bilayer components of the different vesicles to mix during preparation. Recently we have developed polymeric vesicles using the new polymer-palmitoyl glycol chitosan and cholesterol in a 2:1 weight ratio. These polymeric vesicles have now been encapsulated within egg phosphatidylcholine (egg PC), cholesterol (2:1 weight ratio) liposomes yielding a vesicle in vesicle system. The vesicle in vesicle system was visualised by freeze fracture electron microscopy. The mixing of the different bilayer components was studied by monitoring the excimer fluorescence of pyrene-labelled polymeric vesicles after their encapsulation within egg PC liposomes or hexadecyl diglycerol ether niosomes. A minimum degree of lipid mixing was observed with the polymeric vesicle-egg PC liposome system when compared to the polymeric vesicle-hexadecyl diglycerol ether niosome system. The polymeric vesicle-egg PC vesicle in vesicle system was shown to retard the release of encapsulated solutes. 28% of 5(6)-carboxyfluorescein (CF) encapsulated in the polymeric vesicle compartment of the vesicle in vesicle system was released after 4 h compared to the release of 62% of encapsulated CF from plain polymeric vesicles within the same time period

    Pion electromagnetic form factor from full lattice QCD

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    We present preliminary results from the first calculation of the pion electromagnetic form factor at physical light quark masses. This form factor parameterises the deviations from the behaviour of a point-like particle when a photon hits the pion. These deviations result from the internal structure of the pion and can thus be calculated in QCD. We use three sets (different lattice spacings) of n_f=2+1+1 lattice configurations generated by the MILC collaboration. The Highly Improved Staggered Quark formalism (HISQ) is used for all of the sea and valence quarks. Using lattice configurations with u/d quark masses very close to the physical value is an advantage, as we avoid the chiral extrapolation. We study the shape of the vector (f_+) form factor in the q^2 range from 0 to -0.12 GeV^2 and extract the mean square radius, &#60;r^2_v&#62;. The shape of the vector form factor and the resulting radius is compared with experiment

    Slip inversion along inner fore-arc faults, eastern Tohoku, Japan

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    The kinematics of deformation in the overriding plate of convergent margins may vary across timescales ranging from a single seismic cycle to many millions of years. In Northeast Japan, a network of active faults has accommodated contraction across the arc since the Pliocene, but several faults located along the inner fore arc experienced extensional aftershocks following the 2011 Tohoku-oki earthquake, opposite that predicted from the geologic record. This observation suggests that fore-arc faults may be favorable for stress triggering and slip inversion, but the geometry and deformation history of these fault systems are poorly constrained. Here we document the Neogene kinematics and subsurface geometry of three prominent fore-arc faults in Tohoku, Japan. Geologic mapping and dating of growth strata provide evidence for a 5.6–2.2 Ma initiation of Plio-Quaternary contraction along the Oritsume, Noheji, and Futaba Faults and an earlier phase of Miocene extension from 25 to 15 Ma along the Oritsume and Futaba Faults associated with the opening of the Sea of Japan. Kinematic modeling indicates that these faults have listric geometries, with ramps that dip ~40–65°W and sole into subhorizontal detachments at 6–10 km depth. These fault systems can experience both normal and thrust sense slip if they are mechanically weak relative to the surrounding crust. We suggest that the inversion history of Northeast Japan primed the fore arc with a network of weak faults mechanically and geometrically favorable for slip inversion over geologic timescales and in response to secular variations in stress state associated with the megathrust seismic cycle.Funding was provided by a grant from the National Science Foundation Tectonics Program grant EAR-0809939 to D.M.F. and E.K., Geologic Society of America Graduate Research Grants, and the P.D. Krynine Memorial Fund. The authors thank Gaku Kimura, Kyoko Tonegawa, Hiroko Watanabe, Jun Kameda, and Asuka Yamaguchi for scientific and logistical support, and Kristin Morell for comments on early versions of the manuscript. We also thank Yuzuru Yamamoto and Kohtaro Ujiie for their detailed reviews and suggestions for improvement to the manuscript. The authors acknowledge the use of the Move Software Suite granted by Midland Valley's Academic Software Initiative. Geologic, structural, stratigraphic, and chronologic data used herein are accessible in manuscript figures, and in the citations therein. Input geologic data for trishear kinematic modeling can be accessed in Table 1 and in the supporting information. (EAR-0809939 - National Science Foundation Tectonics Program grant; Geologic Society of America Graduate Research Grants; P.D. Krynine Memorial Fund

    Nonperturbative tests of the renormalization of mixed clover-staggered currents in lattice QCD

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    The Fermilab Lattice and MILC collaborations have shown in one-loop lattice QCD perturbation theory that the renormalization constants of vector and axial-vector mixed clover-asqtad currents are closely related to the product of those for clover-clover and asqtad-asqtad (local) vector currents. To be useful for future higher precision calculations this relationship must be valid beyond one-loop and very general. We test its validity nonperturbatively using clover and Highly Improved Staggered (HISQ) strange quarks, utilising the absolute normalization of the HISQ temporal axial current. We find that the renormalization of the mixed current differs from the square root of the product of the pure HISQ and pure clover currents by 2−3%. We also compare discretization errors between the clover and HISQ formalisms

    Cautionary note on the use of omega squared to evaluate the effectiveness of behavioral treatments

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    Journal ArticleEstimating the magnitude of treatment effects has been recommended as a solution to the problems associated with conventional hypothesis testing. In comparison to tradition statistical tests of treatment effectiveness, omega squared (ω2) and related magnitude of effect statistics provide a graduated rather than a dichotomous judgmental aid, index the strength of the relationship between treatment and outcome, and are unaffected by aspects of statistical power related to sample size. Unfortunately, these correlational statistics also have characteristics that limit their interpretative value

    Characterization of the phosphotyrosyl protein phosphatase activity of calmodulin-dependent protein phosphatase.

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    Journal ArticleCalmodulin-dependent protein phosphatase from bovine brain and heart was assayed for phosphotyrosine and phosphoserine phosphatase activity using several substrates: 1) smooth muscle myosin light chain (LC20) phosphorylated on tyrosine or serine residues, 2) angiotensin I phosphorylated on tyrosine, and 3) synthetic phosphotyrosine- or phosphoserine-containing peptides with amino acid sequences patterned after the autophosphorylation site in Type II regulatory subunit of the cAMP-dependent protein kinase. The phosphatase was activated by Ni2+ and Mn2+, and stimulated further by calmodulin. In the presence of Ni2+ and calmodulin, it exhibited similar kinetic constants for the dephosphorylation of phosphotyrosyl LC20 (Km = 0.9 microM, and Vmax = 350 nmol/min/mg) and phosphoseryl LC20 (Km = 2.6 microM, Vmax = 690 nmol/min/mg). Dephosphorylation of phosphotyrosyl LC20 was inhibited by phosphoseryl LC20 with an apparent Ki of 2 microM. Compared to the reactions with phosphotyrosyl LC20 as the substrate, reactions with phosphotyrosine-containing oligopeptides exhibited slightly higher Km and lower Vmax values. The reaction with the phosphoseryl peptide based on the Type II regulatory subunit sequence exhibited a slightly higher Km (23 microM), but a much higher Vmax (4400 nmol/min/mg) than that with its phosphotyrosine-containing counterpart. Micromolar concentrations of Zn2+ inhibited the phosphatase activity; vanadate was less potent, and 25 mM NaF was ineffective. The study provides quantitative data to serve as a basis for comparing the ability of the calmodulin-dependent protein phosphatase to act on phosphotyrosine- and phosphoserine-containing substrates
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