1,105 research outputs found

    Maryland Mechanics\u27 Lien Law - Its Scope and Effect

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    Redefining Europe’s economic sovereignty. Policy Contribution Issue n˚9 | June 2019. Bruegel

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    Executive summary Europeans like to believe the European Union has the collective economic size and capacity to determine its own economic destiny. But the behaviour of others global powers is increasingly calling this ability into question. China and the United States, especially, do not separate economic interests from geopolitical interests in the same way the EU does. They are increasingly using economic connections, from cyberspace to financial links, to gain geopolitical advantage or to serve geopolitical goals. Europe’s economic sovereignty is at stake. The problem for Europe is real but manageable. This Policy Contribution examines the specific problems that China and the US pose for European economic sovereignty, and considers how the EU and its member states can better protect European economic sovereignty in a range of areas, including state aid to domestic industries, competition policy, investment screening, export controls, the international role of the euro, the role of European development banks, the European payments infrastructure and the global governance system. In each area, we recommend ways to improve the EU’s capacity to wield economic power, without advocating increased protectionism or a retreat from globalisation. We make recommendations on how to adapt the EU and national policy systems to better integrate economic and geopolitical considerations. The next European Commission should develop an economic sovereignty strategy to boost Europe’s research and scientific base, protect assets critical to national security from foreign interference, enforce a level playing field in domestic and international competition, and strengthen European monetary and financial autonomy. To guide the implementation of this strategy, an economic sovereignty committee should be established that will seek to integrate economic and security considerations within the European Commission. But the answer to this problem does not lie only in Brussels. We recommend a flexible implementation strategy that connects with member-state policy debates and makes use of ‘mini-lateral’ groups of member states

    Supernovae, Landau Levels, and Pulsar Kicks

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    We derive the energy asymmetry given the proto-neutronstar during the time when the neutrino sphere is near the surface of the proto-neutron star, using the modified URCA process. The electrons produced with the anti-neutrinos are in Landau levels due to the strong magnetic field, and this leads to asymmetry in the neutrino momentum, and a pulsar kick. Our main prediction is that the large pulsar kicks start at about 10 s and last for about 10 s, with the corresponding neutrinos correlated in the direction of the magnetic field.Comment: 10 pages, seven figure

    Shape, shear and flexion II - Quantifying the flexion formalism for extended sources with the ray-bundle method

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    Flexion-based weak gravitational lensing analysis is proving to be a useful adjunct to traditional shear-based techniques. As flexion arises from gradients across an image, analytic and numerical techniques are required to investigate flexion predictions for extended image/source pairs. Using the Schwarzschild lens model, we demonstrate that the ray-bundle method for gravitational lensing can be used to accurately recover second flexion, and is consistent with recovery of zero first flexion. Using lens plane to source plane bundle propagation, we find that second flexion can be recovered with an error no worse than 1% for bundle radii smaller than {\Delta}{\theta} = 0.01 {\theta}_E and lens plane impact pararameters greater than {\theta}_E + {\Delta}{\theta}, where {\theta}_E is the angular Einstein radius. Using source plane to lens plane bundle propagation, we demonstrate the existence of a preferred flexion zone. For images at radii closer to the lens than the inner boundary of this zone, indicative of the true strong lensing regime, the flexion formalism should be used with caution (errors greater than 5% for extended image/source pairs). We also define a shear zone boundary, beyond which image shapes are essentially indistinguishable from ellipses (1% error in ellipticity). While suggestive that a traditional weak lensing analysis is satisfactory beyond this boundary, a potentially detectable non-zero flexion signal remains.Comment: 14 pages, 13 figures, accepted for publication in Monthly Notices of the Royal Astronomical Societ

    Spectropolarimetry of the Type Ib/c SN 2005bf

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    We present spectropolarimetric observations of the peculiar Type Ib/c SN 2005bf, in MCG+00-27-005, from 3600-8550\AA. The SN was observed on 2005 April 30.9, 18 days after the first B-band light-curve maximum and 6 days before the second B-band light-curve maximum. The degree of the Interstellar Polarization, determined from depolarized emission lines in the spectrum, is found to be large with pmax(ISP)=1.6p_{max}(ISP)=1.6% and Ξ(ISP)=149\theta(ISP)=149\fdg7±4.07\pm4.0, but this may be an upper limit on the real value of the ISP. After ISP subtraction, significant polarization is observed over large wavelength regions, indicating a significant degree of global asymmetry, ≳10\gtrsim 10%. Polarizations of 3.5% and 4% are observed for absorption components of Ca II H&K and IR triplet, and 1.3% for He I 5876\AA and Fe II. On the Q−UQ-U plane clear velocity-dependent loop structure is observed for the He I 5876\AA line, suggestive of departures from an axial symmetry and possible clumping of the SN ejecta. Weak High Velocity components of Hα\mathrm{H\alpha}, HÎČ\mathrm{H\beta} and HÎł\mathrm{H\gamma} are observed, with velocities of -15 000\kms. The low degree of polarization observed at HÎČ\beta suggests that the polarization observed for the other Balmer lines (∌0.4\sim 0.4% above the background polarization) may rather be due to blending of Hα\mathrm{H\alpha} and HÎł\mathrm{H\gamma} with polarized Si II and Fe II lines, respectively. We suggest a model in which a jet of material, that is rich in 56Ni\mathrm{^{56}Ni}, has penetrated the C-O core, but not the He mantle. The jet axis is tilted with respect to the axis of the photosphere. This accounts for the lack of significant polarization of O I 7774\AA, the delayed excitation and, hence, observability of He I and, potentially, the varied geometries of He and Ca.Comment: 12 pages, 7 figures (3 colour), MNRAS accepte

    Influence of cardiac motion on Doppler measurements using in vitro and in vivo models

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    AbstractObjectives. Using both in vitro and in vivo techniques, we investigated the extent to which cardiac motion alters Doppler-measured blood flow velocity and thus potentially can alter the calculation of valve areas or pressure gradients.Background. Blood fiow velocity measured by Doppler ultrasound represents the net motion of the blood relative to the transducer. It is widely assumed that the measured velocity represents the actual flow. It has been demonstrated that cardiac motion generates regularly occurring low velocity Doppler signals that are commonly treated as artifact.Methods. We used an in vitro model that allowed us to measure and independently control the flow of a liquid through a chamber and the motion of the chamber relative to the Doppler beam. A cornstarch-water slurry was driven by a pulsatile pump through tubing to simulate the blood flow within the heart, and the tubing was cyclically moved by a piston to simulate the heart motion. We also measured cardiac motion using M-mode and two-dimensional echocardiography and compared the results with the Doppler signal derived from cardiac motion in subjects without cardiac disease.Results. In the in vitro model, alteration in the motion of the tubing resulted in apparent changes in the measured maximal velocity of the fluid. The Doppler spectrum of the combined motion of the tubing and the fluid was the algebraic sum of their Doppler signals. In human subjects, the maximal slope of the M-mode tracing of the aortic annular motion and the peak Doppler signal due to cardiac motion were compared and were highly correlated.Conclusions. Cardiac motion alters the Doppler signal derived from blood flow. This effect can be demonstrated in vitro and in vivo

    On the informational content of wage offers

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    This article investigates signaling and screening roles of wage offers in a single-play matching model with two-sided unobservable characteristics. It generates the following predictions as matching equilibrium outcomes: (i) “good” jobs offer premia if “high-quality” worker population is large; (ii) “bad” jobs pay compensating differentials if the proportion of “good” jobs to “low-quality” workers is large; (iii) all firms may offer a pooling wage in markets dominated by “high-quality” workers and firms; or (iv) Gresham’s Law prevails: “good” types withdraw if “bad” types dominate the population. The screening/signaling motive thus has the potential of explaining a variety of wage patterns
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