5 research outputs found

    Calibration of the CMS Drift Tube Chambers and Measurement of the Drift Velocity with Cosmic Rays

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    Diagnosis and characteristics of syncope in older patients referred to geriatric departments.

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    OBJECTIVES: To test the applicability and safety of a standardized diagnostic algorithm in geriatric departments and to define the prevalence of different causes of syncope in older patients. DESIGN: Multicenter cross-sectional observational study. SETTING: In-hospital geriatric acute care departments and outpatient clinics. PARTICIPANTS: Two hundred forty-two patients(aged>or=65, mean+/-standard deviation=79+/-7, range 65-98) consecutively referred for evaluation of transient loss of consciousness to any of six clinical centers participating in the study. Of these, 11 had a syncope-like condition (5 transient ischemic attack; 6 seizures), and 231 had syncope (aged 65-74, n=71; aged>or=75, n=160). MEASUREMENTS: Protocol designed to define etiology and clinical characteristics of syncope derived from European Society of Cardiology Guidelines on syncope. RESULTS: No major complication occurred with use of the protocol. Neurally mediated was the more prevalent form of syncope in this population (66.6%). Cardiac causes accounted for 14.7% of all cases. The neuroreflex form of syncope (vasovagal, situational, and carotid sinus syndrome) was more common in younger than in older patients (62.3% vs 36.2%; P=.001), whereas orthostatic syncope was more frequent in the older than in the younger group (30.5% vs 4.2%; P<.001). In only 10.4% of cases, syncope remained of unexplained origin. After initial evaluation, a definite diagnosis was possible in 40.1% of the cases, and a suspected diagnosis was obtained in 57.9%. Syncope of suspected cardiac origin after initial evaluation was confirmed in 43.7% of cases, and neuromediated causes were confirmed in 83.5% of the cases. CONCLUSION: The protocol is applicable even beyond the age of 90 in geriatric departments. The standardized protocol is associated with a reduction in the frequency of unexplained syncope to about 10%

    Calibration of the CMS drift tube chambers and measurement of the drift velocity with cosmic rays

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    This paper describes the calibration procedure for the drift tubes of the CMS barrel muon system and reports the main results obtained with data collected during a high statistics cosmic ray data-taking period. The main goal of the calibration is to determine, for each drift cell, the minimum time delay for signals relative to the trigger, accounting for the drift velocity within the cell. The accuracy of the calibration procedure is influenced by the random arrival time of the cosmic muons relative to the LHC clock cycle. A more refined analysis of the drift velocity was performed during the offline reconstruction phase, which takes into account this feature of cosmic ray events
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