Extreme ultra-trail race induces muscular damage, risk for acute kidney injury and hyponatremia: A case report

A case study involving a healthy trained male athlete who completed a 786 km multistage ultra-trail race. Several markers were analyzed in blood and urine samples: creatinine (SCR) for kidney damage, sodium ([Na+]) for hyponatremia, creatine kinase (CK) for exertional rhabdo-myolysis, as well as other hematological values. Samples were taken before and after the race and during the recovery period (days 2 and 9 after the race). Results showed: SCR = 1.13 mg/dL, [Na+] =139 mmol/L and CK = 1.099 UI/L. Criteria for the determination of acute kidney damage were not met, and [Na+] concentration was above 135 mEq/L, indicating the absence of hyponatremia. Exer-tional rhabdomyolysis was suffered by the athlete (baseline CK increased fivefold), though this situation was reverted after 9 days of recovery. Ultra-trail races cause biochemical changes in athletes, which should be known about by healthcare professionals. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

The variable finesse locking technique

Virgo is a power recycled Michelson interferometer, with 3 km long Fabry-Perot cavities in the arms. The locking of the interferometer has been obtained with an original lock acquisition technique. The main idea is to lock the instrument away from its working point. Lock is obtained by misaligning the power recycling mirror and detuning the Michelson from the dark fringe. In this way, a good fraction of light escapes through the antisymmetric port and the power build-up inside the recycling cavity is extremely low. The benefit is that all the degrees of freedom are controlled when they are almost decoupled, and the linewidth of the recycling cavity is large. The interferometer is then adiabatically brought on to the dark fringe. This technique is referred to as variable finesse, since the recycling cavity is considered as a variable finesse Fabry-Perot. This technique has been widely tested and allows us to reach the dark fringe in few minutes, in an essentially deterministic way

A Cross-correlation method to search for gravitational wave bursts with AURIGA and Virgo

We present a method to search for transient GWs using a network of detectors with different spectral and directional sensitivities: the interferometer Virgo and the bar detector AURIGA. The data analysis method is based on the measurements of the correlated energy in the network by means of a weighted cross-correlation. To limit the computational load, this coherent analysis step is performed around time-frequency coincident triggers selected by an excess power event trigger generator tuned at low thresholds. The final selection of GW candidates is performed by a combined cut on the correlated energy and on the significance as measured by the event trigger generator. The method has been tested on one day of data of AURIGA and Virgo during September 2005. The outcomes are compared to the results of a stand-alone time-frequency coincidence search. We discuss the advantages and the limits of this approach, in view of a possible future joint search between AURIGA and one interferometric detector.Comment: 11 pages, 6 figures, submitted to CQG special issue for Amaldi 7 Proceeding

Astrophysically Triggered Searches for Gravitational Waves: Status and Prospects

In gravitational-wave detection, special emphasis is put onto searches that focus on cosmic events detected by other types of astrophysical observatories. The astrophysical triggers, e.g. from gamma-ray and X-ray satellites, optical telescopes and neutrino observatories, provide a trigger time for analyzing gravitational wave data coincident with the event. In certain cases the expected frequency range, source energetics, directional and progenitor information is also available. Beyond allowing the recognition of gravitational waveforms with amplitudes closer to the noise floor of the detector, these triggered searches should also lead to rich science results even before the onset of Advanced LIGO. In this paper we provide a broad review of LIGO's astrophysically triggered searches and the sources they target

A simple line detection algorithm applied to Virgo data

International audienceWe propose a new method for the detection of spectral lines in random noise. It mimics the processing scheme of matching filtering, i.e., a whitening procedure combined with the measurement of the correlation between the data and a template. Thanks to the original noise spectrum estimate used in the whitening procedure, the algorithm can easily be tuned to various types of noise. It can thus be applied to the data taken from a wide class of sensors. This versatility and its small computational cost make this method particularly well suited for real-time monitoring in gravitational wave experiments. We show the results of its application to Virgo C4 commissioning data

A first test of a sine-Hough method for the detection of pulsars in binary systems using the E4 Virgo engineering run data

Most of the known pulsars with frequencies lying in the best sensitivity range of the Virgo/LIGO/TAMA interferometers belong to binary systems. Accordingly their frequencies are Doppler shifted in an unknown way. We investigate a new method to search for and extract the parameters of such pulsars. A first preliminary test of this method, performed on the Virgo data recorded during the E4 engineering run, is presented

A first study of environmental noise coupling to the Virgo interferometer

International audienceDuring the commissioning of the Virgo interferometer, a search for environmental noise contributions to the dark fringe signal was undertaken. Dedicated tests have been performed to identify major sources of disturbances and to understand the coupling mechanism with the interferometer. The major effect is due to seismic/acoustic noise coupling to the laser beam before the input mode cleaner, then propagating as beam power noise to the ITF dark fringe output signal. In this paper we illustrate the tests performed and preliminary results of our investigation

Interferometric detectors of gravitational waves on Earth: the next generations

International audienceThe interferometric detectors of gravitational waves of first generation are now taking data. A first detection might be possible with these instruments, but more sensitive detectors will be needed to start the gravitational wave astronomy. The interferometers of second generation will improve the sensitivity by a factor ten, allowing to explore a universe volume 1000 times larger. The technology is almost ready and the construction will start at the beginning of next decade. The community of the physicists involved in the field has also started to make plans for third generation detectors, for which a long term technology development will be required. The plans for the upgrades of the existing detectors and the scenario for the evolution of the field will be reviewed in this paper

Noise budget and noise hunting in VIRGO

International audienc