Chern-Weil theory for line bundles with the family Arakelov metric

We prove a result of Chern-Weil type for canonically metrized line bundles on one-parameter families of smooth complex curves. Our result generalizes a result due to J.I. Burgos Gil, J. Kramer and U. K\"uhn that deals with a line bundle of Jacobi forms on the universal elliptic curve over the modular curve with full level structure, equipped with the Petersson metric. Our main tool, as in the work by Burgos Gil, Kramer and K\"uhn, is the notion of a b-divisor.Comment: 34 page

Fiscal policy in the European Economic and Monetary Union

At the heart of fiscal rules in the EU is the (in)famous 3%-threshold: countries should avoid deficits exceeding 3% of GDP. If deficits exceed 3% of GDP, countries are to undertake consolidation ef-forts. This rule has been hotly debated since its introduction. Many argue that it is inherently procy-clical, by forcing countries with ‘excessive’ deficits to consolidate during recessions. Others stress the poor compliance with European fiscal rules.Two chapters investigate the effectiveness of European fiscal rules. On the plus side, if recom-mended to consolidate, member states do impose fiscal measures aimed at reducing excessive budget deficits. At the same time, and less desirable, the 3%-rule seems to elicit strategic behavior. Fiscal forecasts for euro area countries by the European Commission, which are used to judge com-pliance with the fiscal rules, are biased upwards when the budget deficit threatens to exceed the 3%-threshold.The next two chapters look into the economic consequences of consolidation efforts during the crisis. Although significant consolidation measures, implemented by the Dutch government, might have come at the expense of economic growth – at least in the short term – they do seem to have improved investors’ perception of the government’s solvency. More generally, public investments were severely reduced in many developed economies. However, results show that in general the decline of public capital has not diminished potential growth, suggesting that the current level of public investments does not pose an immediate threat to potential output in most countries

Ultrasound-induced Gas Release from Contrast Agent Microbubbles

We investigated gas release from two hard-shelled ultrasound contrast agents by subjecting them to high-mechanical index (MI) ultrasound and simultaneously capturing high-speed photographs. At an insonifying frequency of 1.7 MHz, a larger percentage of contrast bubbles is seen to crack than at 0.5 MHz. Most of the released gas bubbles have equilibrium diameters between 1.25 and 1.75 /spl mu/m. Their disappearance was observed optically. Free gas bubbles have equilibrium diameters smaller than the bubbles from which they have been released. Coalescence may account for the long dissolution times acoustically observed and published in previous studies. After sonic cracking, the cracked bubbles stay acoustically active

Noninvasive microbubble-based pressure measurements: a simulation study

This paper describes a noninvasive method to measure local hydrostatic pressures in fluid filled cavities. The method is based on the disappearance time of a gas bubble, as the disappearance time is related to the hydrostatic pressure. When a bubble shrinks, its response to ultrasound changes. From this response, the disappearance time, and with it the hydrostatic pressure, can be determined. We investigated the applicability of the gases Ar, C3F8, Kr, N2, Ne, and SF6, based on their diffusive properties. For pressure measurements with a limited duration, e.g. 150 ms, Kr and Ar bubbles are most suitable, since they are most sensitive to pressure change. If there is also a limitation to bubble size, e.g. a maximum diameter of 6 lm, SF6 is most suitable. We present improvements of a method that correlates the duration of the decay of the fundamental ultrasound response to the hydrostatic overpressure. We propose to correlate the duration until subharmonic occurrence in combination with its decay, to hydrostatic overpressure, since the subharmonic decays more rapidly than the fundamental response. For a dissolving Ar gas bubble with an initial diameter of 14 lm, the overpressure can be determined 4 times as precise from the decay of the subharmonic response as from the decay of the fundamental response. Overpressures as small as 11 mmHg may be discriminated with this method