Assessing noise sources at synchrotron infrared ports.

Today, the vast majority of electron storage rings delivering synchrotron radiation for general user operation offer a dedicated infrared port. There is growing interest expressed by various scientific communities to exploit the mid-IR emission in microspectroscopy, as well as the far infrared (also called THz) range for spectroscopy. Compared with a thermal (laboratory-based source), IR synchrotron radiation sources offer enhanced brilliance of about two to three orders of magnitude in the mid-IR energy range, and enhanced flux and brilliance in the far-IR energy range. Synchrotron radiation also has a unique combination of a broad wavelength band together with a well defined time structure. Thermal sources (globar, mercury filament) have excellent stability. Because the sampling rate of a typical IR Fourier-transform spectroscopy experiment is in the kHz range (depending on the bandwidth of the detector), instabilities of various origins present in synchrotron radiation sources play a crucial role. Noise recordings at two different IR ports located at the Swiss Light Source and SOLEIL (France), under conditions relevant to real experiments, are discussed. The lowest electron beam fluctuations detectable in IR spectra have been quantified and are shown to be much smaller than what is routinely recorded by beam-position monitors.

[Risk assessment before non-cardiac surgery: what do anesthesiologists expect from cardiologists?]. / Evaluation du risque cardiologique en vue d'une anesthésie pour une chirurgie non cardiaque: qu'attend le médecin anesthésiste-réanimateur de la consultation spécialisée auprès d'un cardiologue?

Patients with a cardiac pathology are at high risk of perioperative cardiac complications. Therefore, an evaluation of the cardiac risk before a non-cardiac surgery has to be performed. The importance of the risk depends on the type of surgery, the patient's clinical symptoms and his adaptation to a physical effort. Exams are chosen according to the pathology, the information searched for and should be non invasive. After the evaluation, a specific preparation of the patient and the institution or an adaptation of cardioprotective medications should be discussed. The cardiologic consultation also allows a better management of antithrombotic or antiplatelet therapy. Preoperative evaluation of the cardiac risk is based on the collaboration between cardiologist and anesthesiologist to select the patients to evaluate, optimize their management, and decrease the risk of complications.