Stability of Transonic Characteristic Discontinuities in Two-Dimensional Steady Compressible Euler Flows

For a two-dimensional steady supersonic Euler flow past a convex cornered wall with right angle, a characteristic discontinuity (vortex sheet and/or entropy wave) is generated, which separates the supersonic flow from the gas at rest (hence subsonic). We proved that such a transonic characteristic discontinuity is structurally stable under small perturbations of the upstream supersonic flow in $BV$. The existence of a weak entropy solution and Lipschitz continuous free boundary (i.e. characteristic discontinuity) is established. To achieve this, the problem is formulated as a free boundary problem for a nonstrictly hyperbolic system of conservation laws; and the free boundary problem is then solved by analyzing nonlinear wave interactions and employing the front tracking method.Comment: 26 pages, 3 figure

Direct Observation of Large Amplitude Spin Excitations Localized in a Spin-Transfer Nanocontact

We report the direct observation of large amplitude spin-excitations localized in a spin-transfer nanocontact using scanning transmission x-ray microscopy. Experiments were conducted using a nanocontact to an ultrathin ferromagnetic multilayer with perpendicular magnetic anisotropy. Element resolved x-ray magnetic circular dichroism images show an abrupt onset of spin excitations at a threshold current that are localized beneath the nanocontact, with average spin precession cone angles of 25{\deg} at the contact center. The results strongly suggest that we have observed a localized magnetic soliton.Comment: 5 pages, 3 figure

Use of bioresorbable vascular scaffold : a meta-analysis of patients with coronary artery disease

BACKGROUND: Differences in outcomes between bioresorbable vascular scaffold (BVS) systems and drug-eluting metal stents (DES) have not been fully evaluated. We aimed to compare clinical and angiographic outcomes in randomised studies of patients with coronary artery disease (CAD), with a secondary analysis performed among registry studies. METHODS: A meta-analysis comparing outcomes between BVS and DES in patients with CAD. Overall estimates of treatment effect were calculated with random-effects model and fixed-effects model. RESULTS: In 6 randomised trials (3818 patients), BVS increased the risk of subacute stent thrombosis (ST) over and above DES (OR 2.14; CI 1.01 to 4.53; p=0.05), with a trend towards an increase in the risk of myocardial infarction (MI) (125 events in those assigned to BVS and 50 to DES; OR 1.36; CI 0.97 to 1.91; p=0.07). The risk of in-device late lumen loss (LLL) was higher with BVS than DES (mean difference 0.08 mm; CI 0.03 to 0.13; p=0.004). There was no difference in the risk of death or target vessel revascularisation (TVR) between the two devices. In 6 registry studies (1845 patients), there was no difference in the risk of death, MI, TVR or subacute ST between the two stents. Final BVS dilation pressures were higher in registry than in randomised studies (18.7±4.6 vs 15.2±3.3 atm; p<0.001). CONCLUSIONS: Patients treated with BVS had an increased risk of subacute ST and slightly higher LLL compared with those with DES, but this might be related to inadequate implantation techniques, in particular device underexpansion.Peer reviewedFinal Published versio

X-Ray Detection of Transient Magnetic Moments Induced by a Spin Current in Cu

We have used a MHz lock-in x-ray spectro-microscopy technique to directly detect changes of magnetic moments in Cu due to spin injection from an adjacent Co layer. The elemental and chemical specificity of x-rays allows us to distinguish two spin current induced effects. We detect the creation of transient magnetic moments of $3\times 10^{-5}$ $\mu_\mathrm{B}$ on Cu atoms within the bulk of the 28 nm thick Cu film due to spin-accumulation. The moment value is compared to predictions by Mott's two current model. We also observe that the hybridization induced existing magnetic moments on Cu interface atoms are transiently increased by about 10% or $4\times 10^{-3}$ $\mu_\mathrm{B}$. This reveals the dominance of spin-torque alignment over Joule heat induced disorder of the interfacial Cu moments during current flow

In vitro propagation oflemon balm (Melissa officinalis L.) through nodal bud culture of adult plant

A simple and efficient two step procedure for in vitro high frequency plant regeneration was developed for clonal propagation oflemon balm (Melissa officinalis) using nodal explants. Nitsch and Murashige and Skoog's medium supplemented with a-naphthalene acetic acid (1.0 mgl-1) supported axillary shoot growth and induction of roots in cultured explants. Nitsch medium showed better morphogenetic response than Murashige and Skoog's medium. Murashige and Skoog's medium fortified .with 2 mgP of either 6,benzyl aminopurine or 6-methyl aminopurine induced rapid proliferation of shoots. Rooting of the differentiated shoots was readily achieved with auxins fortified to Nitsch medium. The plantlets exhibited 80-90% success in establishment under glasshouse conditions. &nbsp

In vitro propagation oflemon balm (Melissa officinalis L.) through nodal bud culture of adult plant

A simple and efficient two step procedure for in vitro high frequency plant regeneration was developed for clonal propagation oflemon balm (Melissa officinalis) using nodal explants. Nitsch and Murashige and Skoog's medium supplemented with a-naphthalene acetic acid (1.0 mgl-1) supported axillary shoot growth and induction of roots in cultured explants. Nitsch medium showed better morphogenetic response than Murashige and Skoog's medium. Murashige and Skoog's medium fortified .with 2 mgP of either 6,benzyl aminopurine or 6-methyl aminopurine induced rapid proliferation of shoots. Rooting of the differentiated shoots was readily achieved with auxins fortified to Nitsch medium. The plantlets exhibited 80-90% success in establishment under glasshouse conditions. &nbsp