6,992 research outputs found
Founder's lecture of the ISS 2006: borderlands of normal and early pathological findings in MRI of the foot and ankle
The purpose of this article is to highlight the anatomical variants, technical pitfalls, and the prevalence of abnormal conditions in the asymptomatic population in magnetic resonance imaging of the foot and ankle. Special attention is drawn to the complex anatomy of the deltoid ligament (the superficial tibionavicular ligament, tibiospring ligament, the tibiocalcaneal ligament, and the deep anterior and posterior tibiotalar ligaments) and the posterior tibial tendon insertion including the magic angle artifact and the high prevalence of asymptomatic findings such as "hypertrophied” peroneal tubercle (abnormal only when larger than 5mm), peroneus quartus (prevalence 17%), and cysts (vascular remnants) just inferior to the angle of Gissan
The CMS High Level Trigger: Commissioning and First Operation with LHC Beams
The CMS experiment will collect data from the proton-proton collisions
delivered by the Large Hadron Collider (LHC) at a centre-of-mass energy up to
14 TeV. The CMS trigger system is designed to cope with unprecedented
luminosities and LHC bunch-crossing rates up to 40 MHz. The unique CMS trigger
architecture only employs two trigger levels. The Level-1 trigger is
implemented using custom electronics. The High Level Trigger is implemented on
a large cluster of commercial processors, the Filter Farm. Trigger menus have
been developed for detector calibration and for fulfilment of the CMS physics
program, at start-up of LHC operations, as well as for operations with higher
luminosities. A complete multipurpose trigger menu developed for an early
instantaneous luminosity of 10^{32}cm{-2}s{-1} has been tested in the HLT
system under realistic online running conditions. The required computing power
needed to process with no dead time a maximum HLT input rate of 50 kHz, as
expected at startup, has been measured, using the most recent commercially
available processors. The Filter Farm has been equipped with 720 such
processors, providing a computing power at least a factor two larger than
expected to be needed at startup. Results for the commissioning of the
full-scale trigger and data acquisition system with cosmic muon runs are
reported. The trigger performance during operations with LHC circulating proton
beams, delivered in September 2008, is outlined and first results are shown.Comment: Published in the Proceedings of the IEEE Nuclear Science
Symposium,October 18-25, 2008,Dresden,German
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