Josephson effect in MgB_2 break junctions

We present the first observation of the DC and AC Josephson effect in MgB_2 break junctions. The junctions, obtained at 4.2 K in high-quality, high-density polycrystalline metallic MgB_2 samples, show a non-hysteretic DC Josephson effect. By irradiating the junctions with microwaves we observe clear Shapiro steps spaced by the ideal $\Delta V$ value. The temperature dependence of the DC Josephson current and the dependence of the height of the steps on the microwave power are obtained. These results are a direct prove for the existence of pairs with charge 2e in this new metallic superconductor and give evidence of the superconductor-normal metal-superconductor weak link character of these junctions.Comment: 4 RevTEX pages, 4 eps figure

Variance Reduction with Monte Carlo Estimates of Error Rates in Multivariate Classification

In this paper, control variates are proposed to speed up Monte Carlo Simulations to estimate expected error rates in multivariate classification

Evidence for pseudogap and phase-coherence gap separation by Andreev reflection experiments in Au/La_{2-x}Sr_{x}CuO_4 point-contact junctions

We present new Au/La_{2-x}Sr_{x}CuO_{4} (LSCO) point-contact conductance measures as a function of voltage and temperature in samples with 0.08 <= x <= 0.2. Andreev reflection features disappear at about the bulk Tc, giving no evidence of gap for T > Tc. The fit of the normalized conductance at any T < Tc supports a (s + d)-wave symmetry of the gap, whose dominant low-T s component follows the Tc(x) curve in contrast with recent angle-resolved photoemission spectroscopy and quasiparticle tunneling data. These results prove the separation between pseudogap and phase-coherence superconducting gap in LSCO at x <= 0.2.Comment: 4 pages, 4 eps figures, 1 table (RevTeX). Labels added to Fig. 1; Fig. 3 resized; references added; short discussion about ballistic contact regime adde

Few Large with Many Small : Banks Size Distribution and Cross-Border Financial Linkages

We estimate the effect of the distribution of banks by asset size on a country\u2019s propensity to engage in cross-border banking. Countries where the distribution of banks by asset size is more skewed to the right (with few large and many small banks) lend more abroad and are recipients of more funds from foreign banks. This is consistent with the fact that large banks, with easier access to the international financial markets, act as a hub for smaller banks and at the same time stand out as safer too-big-to fail counterparts for foreign partners

Development of a low profile laser Doppler probe for monitoring perfusion at the patient – mattress interface

The clinical importance of pressure ulcers is reviewed confirming the need for continuous monitoring of skin blood perfusion at the patient – mattress interface. The design of a low profile (H≈1mm) laser Doppler probe is then described together with the experimental setup used for evaluation. The results show that the performance of the new sensor does not vary significantly from that of currently available probes over a wide range of operating parameters. The authors conclude that the sensor design provides a low cost perfusion monitoring solution with potential to significantly reduce the risk of bed sores in hospital patients

Relational Contracts and Trust in a High-Tech Industry

We study how informal buyer-supplier relationships in the German automotive industry affect procurement. Using unique data from a survey focusing on these, we show that more trust, the belief that the trading partner acts to maintain the mutual relationship, is associated with both higher quality of the automotive parts and more competition among suppliers. Yet both effects hold only for parts involving unsophisticated technology, not when technology is sophisticated. We rationalize these findings within a relational contracting model that critically focuses on changes in the bargaining power, due to differences in the costs of switching suppliers