An upper limit on the stochastic gravitational-wave background of cosmological origin.

A stochastic background of gravitational waves is expected to arise from a superposition of a large number of unresolved gravitational-wave sources of astrophysical and cosmological origin. It should carry unique signatures from the earliest epochs in the evolution of the Universe, inaccessible to standard astrophysical observations. Direct measurements of the amplitude of this background are therefore of fundamental importance for understanding the evolution of the Universe when it was younger than one minute.

[The proximal open-wedge osteotomy with interlocking plate for correction of splayfoot deformities with hallux valgus].

Objective: Correction of splayfoot deformity through reduction of the increased first intermetatarsal angle by a proximal open-wedge osteotomy.

Indications: Splayfoot deformity with a first intermetatarsal angle > 14 degrees and hallux valgus deformity in younger patients. Splayfoot deformities with a short first metatarsal.

In-vacuum optical isolation changes by heating in a Faraday isolator.

We describe a model evaluating changes in the optical isolation of a Faraday isolator when passing from air to vacuum in terms of different thermal effects in the crystal. The changes are particularly significant in the crystal thermal lensing (refraction index and thermal expansion) and in its Verdet constant and can be ascribed to the less efficient convection cooling of the magneto-optic crystal of the Faraday isolator. An isolation decrease by a factor of 10 is experimentally observed in a Faraday isolator that is used in a gravitational wave experiment (Virgo) with a 10 W input laser when going from air to vacuum.

Measurement of the optical parameters of the Virgo interferometer.

The Virgo interferometer, aimed at detecting gravitational waves, is now in a commissioning phase. Measurements of its optical properties are needed for the understanding of the instrument. We present the techniques developed for the measurement of the optical parameters of Virgo.

Analysis of N-acyl-L-homoserine lactones produced by Burkholderia cepacia with partial filling micellar electrokinetic chromatography--electrospray ionization-ion trap mass spectrometry.

A method for the analysis of N-acyl-L-homoserine lactones (AHLs) with micellar electrokinetic chromatography coupled to electrospray ionization-ion trap mass spectrometry, combining the flexibility of capillary electrophoresis with the unmatched structural information provided by mass spectrometry is presented. Different surfactants were evaluated, with sodium dodecyl sulfate (SDS) yielding the best results considering sensitivity and flexibility. We examined the interaction of AHLs with the SDS micelles at different analysis conditions and applied the optimized method to the analysis of a real bacterial sample.