4,198 research outputs found
Sensitivity Studies with the SPS Rest Gas Profile Monitor
During the SPS run in the year 2000 further test measurements were performed with the rest gas monitor. First, profiles of single circulating proton bunches were measured and the bunch charge progressively reduced, in order to determine the smallest bunch intensity which can be scanned under the present operating conditions. The image detector in this case was a CMOS camera. Using a multi-anode strip photo-multiplier with fast read-out electronics, the possibility to record profiles on a single beam passage and on consecutive turns was also investigated. This paper presents the results of these tests and discusses the expected improvements for the operation in 2001. Moreover, the issue of micro channel plate ageing effects was tackled and a calibration system based on electron emission from a heating wire is proposed. The gained experience will be used for the specification of a new monitor with optimised design, to be operated both in the SPS and in the LHC
Preliminary test of a luminescence profile monitor in the CERN SPS
In order to satisfy the tight emittance requirements of LHC, a non-intercepting beam profile monitor is needed in the SPS to follow the beam emittance evolution during the acceleration cycle from 26 to 450 GeV. Beyond 300 GeV, the synchrotron light monitor can be used. To cover the energy range from injection at 26 GeV to 300 GeV, a monitor based on the luminescence of gas injected in the vacuum chamber has been tested and has given interesting results. This monitor could also be used in LHC, where the same problem arises. Design and results are presented for the SPS monitor
Cosmic rays studied with a hybrid high school detector array
The LORUN/NAHSA system is a pathfinder for hybrid cosmic ray research
combined with education and outreach in the field of astro-particle physics.
Particle detectors and radio antennae were mainly setup by students and placed
on public buildings. After fully digital data acquisition, coincidence
detections were selected. Three candidate events confirmed a working prototype,
which can be multiplied to extend further particle detector arrays on high
schools.Comment: 10 pages, 6 figures. Nigl, A., Timmermans, C., Schellart, P.,
Kuijpers, J., Falcke, H., Horneffer, A., de Vos, C. M., Koopman, Y., Pepping,
H. J., Schoonderbeek, G., Cosmic rays studied with a hybrid high school
detector array, Europhysics News (EPN), Vol. 38, No. 5, accepted on
22/08/200
Consistency of the Shannon entropy in quantum experiments
The consistency of the Shannon entropy, when applied to outcomes of quantum
experiments, is analysed. It is shown that the Shannon entropy is fully
consistent and its properties are never violated in quantum settings, but
attention must be paid to logical and experimental contexts. This last remark
is shown to apply regardless of the quantum or classical nature of the
experiments.Comment: 12 pages, LaTeX2e/REVTeX4. V5: slightly different than the published
versio
The Luminescence Profile Monitor of the CERN SPS
The SPS luminescence monitor is the first device of this type to be used in a high energy accelerator, from 14 to 450 GeV, where up till now the light production was considered to be insufficient. It uses Nitrogen at pressures as low as 4 10-6 Pa as the scintillation medium. Light production, spectrum and decay times have been measured and compared with theory and existing low energy data. They are important factors for the design of such monitors for other machines, for example LHC
The Dipole Moments and Molar Refractions of Several Trans-Beta-Nitrostyrenes
The dipole moments and molar refractions are reported for p-nitrostyrene (4.24 D, 44.3 ml.), trans-betanitrostyrene (4.50 D, 45.7 ml.), the p-methoxy (5.45 D, 56.3 ml.), p-methyl (4.97 D, 52.0 ml.), p-fluoro (3-12 D, 45.5ml), p-chloro (2.90 D, 51.8 ml.), p-bromo (3.02 D, 54.4 ml.), p-iodo (3.26 D, 58.0 ml.), p-nitro (0.83 D, 52.0 ml.), and p-cyano 0.96 D, 47.9 ml.) derivatives of trans-beta-nitrostyrene. It is suggested that the large dipole moments obtained for the p-nitro and p-cyano-beta-nitrostyrenes may be due to unusually large atomic polarizations which would not be taken into consideration by the present method of measurement and calculation
Additional work of breathing from trigger errors in mechanically ventilated children
BACKGROUND: Patient-ventilator asynchrony is associated with increased morbidity and mortality. A direct causative relationship between Patient-ventilator asynchrony and adverse clinical outcome have yet to be demonstrated. It is hypothesized that during trigger errors excessive pleural pressure swings are generated, contributing to increased work-of-breathing and self-inflicted lung injury. The objective of this study was to determine the additional work-of-breathing and pleural pressure swings caused by trigger errors in mechanically ventilated children. METHODS: Prospective observational study in a tertiary paediatric intensive care unit in an university hospital. Patients ventilated > 24 h and < 18 years old were studied. Patients underwent a 5-min recording of the ventilator flow-time, pressure-time and oesophageal pressure-time scalar. Pressure-time-product calculations were made as a proxy for work-of-breathing. Oesophageal pressure swings, as a surrogate for pleural pressure swings, during trigger errors were determined. RESULTS: Nine-hundred-and-fifty-nine trigger errors in 28 patients were identified. The additional work-of-breathing caused by trigger errors showed great variability among patients. The more asynchronous breaths were present the higher the work-of-breathing of these breaths. A higher spontaneous breath rate led to a lower amount of trigger errors. Patient-ventilator asynchrony was not associated with prolonged duration of mechanical ventilation or paediatric intensive care stay. CONCLUSIONS: The additional work-of-breathing caused by trigger errors in ventilated children can take up to 30-40% of the total work-of-breathing. Trigger errors were less common in patients breathing spontaneously and those able to generate higher pressure-time-product and pressure swings. TRIAL REGISTRATION: Not applicable
Mechanical similarity as a generalization of scale symmetry
In this paper we study the symmetry known as mechanical similarity (LMS) and
present for any monomial potential. We analyze it in the framework of the
Koopman-von Neumann formulation of classical mechanics and prove that in this
framework the LMS can be given a canonical implementation. We also show that
the LMS is a generalization of the scale symmetry which is present only for the
inverse square potential. Finally we study the main obstructions which one
encounters in implementing the LMS at the quantum mechanical level.Comment: 9 pages, Latex, a new section adde
Clinicopathological features and outcome in advanced colorectal cancer patients with synchronous vs metachronous metastases
Contains fulltext :
88999.pdf (publisher's version ) (Open Access)BACKGROUND: Synchronous metastases of colorectal cancer (CRC) are considered to be of worse prognostic value compared with metachronous metastases, but only few and conflicting data have been reported on this issue. METHODS: We retrospectively investigated patient demographics, primary tumour characteristics and overall survival (OS) in 550 advanced CRC patients with metachronous vs synchronous metastases, who participated in the phase III CAIRO study. For this purpose only patients with a prior resection of the primary tumour were considered. RESULTS: The clinical and pathological characteristics associated with poor prognosis that we observed more often in patients with synchronous metastases (n=280) concerned an abnormal serum lactate dehydrogenase (LDH) concentration (P=0.01), a worse WHO performance status (P=0.02), primary tumour localisation in the colon (P=0.002) and a higher T stage (P=0.0006). No significant difference in median OS was observed between patients with synchronous metastases and metachronous metastases (17.6 vs 18.5 months, respectively, P=0.24). CONCLUSION: Despite unfavourable clinicopathological features in patients with synchronous metastases with a resected primary tumour compared to patients with metachronous metastases, no difference in the median OS was observed. Possible explanations include a (partial) chemoresistance in patients with metachronous disease because of previous adjuvant treatment, whereas differences between the two groups in screening procedures resulting in a lead time bias to diagnosis or in prognostic molecular markers remain speculative
Exploring physiological signals on people with Duchenne muscular dystrophy for an active trunk support: a case study
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