Long-term outcome after anterior cervical discectomy without fusion

To retrospectively study the long-term outcome of patients after anterior cervical discectomy without fusion (ACD) compared to results published on the long-term outcome after ACD with fusion (ACDF). We reviewed the charts of all patients receiving ACD surgery between 1985 and 2000 to analyze the direct post-operative results as well as complications of the surgery. Moreover, 102 patients, randomly selected, were interviewed with the neck disability index to study possible persisting complaints up to 18 years after ACD surgery. A total of 551 Patients were identified. Two months post-operative follow up at the outpatient clinic revealed that 90.1% of patients were satisfied with the result of ACD surgery. At the time of the survey, this percentage had dropped to 67.6%. In addition, 20.6% and 11.8% had obtained moderate to severe complaints, respectively, in daily-life activities. Complaints were mainly localized in the neck region and occasionally provoked radiating pain in the arm. On the short term, ACD leads to a satisfied outcome. Over the longer term, patients report increasing complaints. The increase in complaints at the time of the survey may be the result of ongoing degenerative effects. Compared to published data on ACDF, there is no superiority of any fusion technique compared to ACD alone

Cavity-enhanced multiplexed comb spectroscopy down to the photon shot noise

International audienceWe demonstrate quantum-noise-limited frequency-comb cavity-enhanced absorption spectroscopy with spectrally multiplexed detection for acquisition times ranging from 10 ms up to 10 min, where a record absorption sensitivity of 7×10-13 cm-1 per spectral element is attained with nW power levels. For this, a widely tuneable frequency-doubled free-running fs Ti:sapphire laser oscillator is coupled to a cavity of extreme finesse (32 000) whose length is modulated and whose output is spectrally dispersed over a linear charge coupled device array. This scheme is robust, as it does not require tight frequency locking or controlling the comb frequency offset, and works with spectrally broad combs, as it is not limited by cavity dispersion

Trace measurement of BrO at the ppt level by a transportable mode-locked frequency-doubled cavity-enhanced spectrometer

International audiencePptv levels of BrO radical have been detected around 338.5-nm wavelength probing a rotationally structured A←X (7,0) electronic transition using mode-locked cavity-enhanced spectroscopy (ML-CEAS). The spectrometer is composed by a widely tunable, broadband frequency-doubled Ti:Sa mode-locked frequency comb laser injected into a high-finesse optical cavity and a high-resolution spectrometer based on a high-order diffraction grating and a high-sensitivity back-thinned CCD camera. A typical minimum detectable absorption coefficient of 1×10-9 cm-1 in 30 s of acquisition has been achieved, leading to a detection limit of 1.7 parts per trillion of BrO at atmospheric pressure. The compact and robust ultrasensitive broadband UV spectrometer is intended to be employed for in situ long-term direct measurements of BrO and other halogenated radicals, thus responding to the lack of analytical techniques to monitor the concentrations of such highly chemically reactive species

Testing for Coordination Fidelity

Operation control in modern distributed systems must rely on decentralised coordination among system participants. In particular when the operation control involves critical infrastructures such as power grids, it is vital to ensure correctness properties of such coordination mechanisms. In this paper, we present a verification technique that addresses coordination protocols for power grid operation control. Given a global protocol specification, we show how we can rely on testing semantics for the purpose of ensuring protocol fidelity, i.e., to certify that the interaction among the grid nodes follows the protocol specification

A Formal Approach to the Engineering of Domain-Specific Distributed Systems

International audienceWe review some results regarding specification, programming and verification of different classes of distributed systems which stemmed from the research of the Concurrency and Mobility Group at University of Firenze. More specifically, we review distinguishing features of network-aware programming, service-oriented computing, autonomic computing, and collective adaptive systems programming. We then present an overview of four different languages,namely KLAIM, COWS, SCEL and AbC. For each language, we discuss design choices, present syntax and informal semantics, show some illustrative examples,and describe programming environments and verification techniques