Nocturnal saturation and respiratory muscle function in patients with chronic obstructive pulmonary disease.

BACKGROUND--Nocturnal desaturations, mainly caused by hypoventilation, occur frequently in patients with chronic obstructive pulmonary disease (COPD). Daytime arterial oxygen and carbon dioxide tensions (PaO2 and PaCO2) appear to predict which patients will desaturate at night. It is unknown if respiratory muscle strength, which may be decreased in these patients, plays an additional part. METHODS--Polysomnography, maximal respiratory pressures, lung function, and arterial blood gas tensions were measured in 34 patients with COPD (mean (SD) forced expiratory volume in one second (FEV1) 41.7 (19.9)% pred). RESULTS--Significant correlations were found between the mean nocturnal arterial oxygen saturation and maximal inspiratory mouth pressure (r = 0.65), maximal inspiratory transdiaphragmatic pressure (r = 0.53), FEV1 (r = 0.61), transfer coefficient (KCO) (r = 0.38), arterial oxygen saturation (SaO2) (r = 0.75), and PaCO2 (r = -0.44). Multiple regression analysis showed that 75% of the variance in nocturnal SaO2 (70%) and FEV1 (5%). CONCLUSION--Inspiratory muscle strength and nocturnal saturation data are correlated, but daytime SaO2 and FEV1 remain the most important predictors of nocturnal saturation

A Fermi gamma-ray burst monitor search for electromagnetic signals coincident with gravitational-wave candidates in Advanced LIGO's first observing run

We present a search for prompt gamma-ray counterparts to compact binary coalescence gravitational wave (GW) candidates from Advanced LIGO's first observing run (O1). As demonstrated by the multimessenger observations of GW170817/GRB 170817A, electromagnetic and GW observations provide complementary information about the astrophysical source, and in the case of weaker candidates, may strengthen the case for an astrophysical origin. Here we investigate low-significance GW candidates from the O1 compact binary coalescence searches using the Fermi Gamma-Ray Burst Monitor (GBM), leveraging its all sky and broad energy coverage. Candidates are ranked and compared to background to measure the significance. Those with false alarm rates (FARs) of less than 10−5 Hz (about one per day, yielding a total of 81 candidates) are used as the search sample for gamma-ray follow-up. No GW candidates were found to be coincident with gamma-ray transients independently identified by blind searches of the GBM data. In addition, GW candidate event times were followed up by a separate targeted search of GBM data. Among the resulting GBM events, the two with the lowest FARs were the gamma-ray transient GW150914-GBM presented in Connaughton et al. and a solar flare in chance coincidence with a GW candidate

Introducing the CTA concept

The Cherenkov Telescope Array (CTA) is a new observatory for very high-energy (VHE) gamma rays. CTA has ambitions science goals, for which it is necessary to achieve full-sky coverage, to improve the sensitivity by about an order of magnitude, to span about four decades of energy, from a few tens of GeV to above 100 TeV with enhanced angular and energy resolutions over existing VHE gamma-ray observatories. An international collaboration has formed with more than 1000 members from 27 countries in Europe, Asia, Africa and North and South America. In 2010 the CTA Consortium completed a Design Study and started a three-year Preparatory Phase which leads to production readiness of CTA in 2014. In this paper we introduce the science goals and the concept of CTA, and provide an overview of the project. © 2013 Elsevier B.V. All rights reserved