26 research outputs found
Neuroscience, Ethics, and National Security: The State of the Art
Military involvement and research in neuroscience generates unique ethical, legal, and social issues that require careful elucidation and consideration in order to align the potentially conflicting needs of national defense, public interest, and scientific progress
First results of the novel photon beam position monitor for undulator beamlines of Elettra RID G-7348-2011
The latest generation SR sources have severe constraints for the stability of the delivered radiation. The high brightness beamlines using undulator radiation are most sensitive to electron beam oscillations. Therefore, photon beam position monitors for undulator radiation are being built as detectors of beam movement and as references for feedback systems. A significant part of the radiation coming from the upstream and downstream dipoles is superimposed on the undulator radiation. A novel detector, incorporating photoelectron analysers, has been developed at Elettra. It can be tuned to the working energy of the undulator from few eV to some keV, the active elements intercepting the tails of the photon distribution. A prototype has been developed for the vertical photon beam position monitoring, and a complete set of characterisation measurements has been performed down to the lowest photon energies of the undulator peak. A description of the detector and its features are presented along with the commissioning results. (C) 2001 Elsevier Science B.V. All rights reserved
A new detector for photon beam position monitoring designed for synchrotron radiation beamlines RID G-7348-2011
For the latest generation of SR sources, local bump orbit feedback systems are being developed for the improvement of the stability of the delivered radiation. The high brightness beamlines using undulator radiation are the most sensitive to electron beam oscillations. Therefore, Photon Beam Position Monitors (PBPM) are being built as detectors of beam movement and as references for feedback systems. The PBPM must not be destructive and has to be suitable for continuous usage. Usual storage ring configurations permit a significant part of the radiation coming from the upstream and downstream dipoles to be superimposed with the undulator radiation. A novel detector, based on spectroscopic techniques, has been developed at ELETTRA. It can be tuned on the working energy of the undulator from a few eV to some keV. A detailed description of the detector layout and its working principle is presented. Its performance with respect to the stability requirements of the beam of synchrotron radiation is also analysed. (C) 2002 Published by Elsevier Science B.V
Recommended from our members
Selective Facial Muscle Activation with Acute and Chronic Multichannel Cuff Electrode Implantation in a Feline Model.
ObjectivesFacial paralysis is a debilitating condition with substantial functional and psychological consequences. This feline-model study evaluates whether facial muscles can be selectively activated in acute and chronic implantation of 16-channel multichannel cuff electrodes (MCE).MethodsTwo cats underwent acute terminal MCE implantation experiments, 2 underwent chronic MCE implantation in uninjured facial nerves (FN) and tested for 6 months, and 2 underwent chronic MCE implantation experiments after FN transection injury and tested for 3 months. The MCE were wrapped around the main trunk of the skeletonized FN, and data collection consisted of EMG thresholds, amplitudes, and selectivity of muscle activation.ResultsIn acute experimentation, activation of specific channels (ie, channels 1-3 and 6-8) resulted in selective activation of orbicularis oculi, whereas activation of other channels (ie, channels 4, 5, or 8) led to selective activation of levator auris longus with higher EMG amplitudes. MCE implantation yielded stable and selective facial muscle activation EMG thresholds and amplitudes up to a 5-month period. Modest selective muscle activation was furthermore obtained after a complete transection-reapproximating nerve injury after a 3-month recovery period and implantation reoperation. Chronic implantation of MCE did not lead to fibrosis on histology. Field steering was achieved to activate distinct facial muscles by sending simultaneous subthreshold currents to multiple channels, thus theoretically protecting against nerve damage from chronic electrical stimulation.ConclusionOur proof-of-concept results show the ability of an MCE, supplemented with field steering, to provide a degree of selective facial muscle stimulation in a feline model, even following nerve regeneration after FN injury.Level of evidenceN/A