456 research outputs found
Results of the EUROTeV Beam-Beam Simulation (BBSIM) Task
This paper is the deliverable of the EUROTeV Beam-Beam Simulation (BBSIM) task and gives an overview of the published results
Modeling of the shared magnets of the ATF Extraction Line
After extraction from the ATF Damping Ring, the linear beam optics is matched before injection into a section dedicated to beam diagnostics. Experimentally, vertical emittances in this section have since several years been observed to be larger than expected, byfactors of two to three, with a seemingly strong dependence on intensity. This has motivated studies of the possible sources of emittance growth. One of these is thought to be the non-linearity experienced by the beam during the extraction, as it is transported off-axis through several magnets which are shared with the Damping Ring. Such non-linearity can generate a sensitivity of the emittance to the orbit parameters in the extraction, which would be very undesirable in the newly built ATF2 final focus system, where the same extraction line is used. In this report, a detailed calculation of the modeling of these shared magnets is presented, in order to quantify the magnitudes of both the linear and non-linear fields to be used in the evaluation of the optics and in tracking simulations of the performance of the extraction line
Les effets du contexte local contraint sur lâĂ©volution du management public territorial : De lâexcellence Ă la performance
National audienc
Evidence of disturbed sleep and increased illness in overreached endurance athletes
PURPOSE: This study aimed to examine whether (i) objective markers of sleep quantity and quality are altered in endurance athletes experiencing overreaching in response to an overload training program and (ii) potential reduced sleep quality would be accompanied with a higher prevalence of upper respiratory tract infections in this population. METHODS: Twenty-seven trained male triathletes were randomly assigned to either overload (n = 18) or normal (CTL, n = 9) training groups. Respective training programs included a 1-wk moderate training phase followed by a 3-wk period of overload or normal training, respectively, and then a subsequent 2-wk taper. Maximal aerobic power and oxygen uptake (VÌO 2max) from incremental cycle ergometry were measured after each phase, whereas mood states and incidences of illness were determined from questionnaires. Sleep was monitored every night of the 6 wk using wristwatch actigraphy. RESULTS: Of the 18 overload training group subjects, 9 were diagnosed as functionally overreached (F-OR) after the overload period, as based on declines in performance and VÌO2max with concomitant high perceived fatigue (P 0.05). There was a significant time-group interaction for sleep duration (SD), sleep efficiency (SE), and immobile time (IT). Only the F-OR group demonstrated a decrease in these three parameters (-7.9% ± 6.7%,-1.6% ± 0.7%, and-7.6% ± 6.6% for SD, SE, and IT, respectively, P < 0.05), which was reversed during the subsequent taper phase. Higher prevalence of upper respiratory tract infections were also reported in F-OR (67%, 22%, and 11% incidence rate for F-OR, AF, and CTL, respectively). CONCLUSION: This study confirms sleep disturbances and increased illness in endurance athletes who present with symptoms of F-OR during periods of high volume training. © 2014 by the American college of Sports Medicine
About the connection between the power spectrum of the Cosmic Microwave Background and the Fourier spectrum of rings on the sky
In this article we present and study a scaling law of the CMB
Fourier spectrum on rings which allows us (i) to combine spectra corresponding
to different colatitude angles (e.g. several detectors at the focal plane of a
telescope), and (ii) to recover the power spectrum once the
coefficients have been measured. This recovery is performed numerically below
the 1% level for colatitudes degrees. In addition, taking
advantage of the smoothness of the and of the , we provide
analytical expressions which allow to recover one of the spectrum at the 1%
level, the other one being known.Comment: 8 pages, 8 figure
HFI L2 DPC destripping and mapmaking modules
PoS(CMB2006)049International audienceThe data processing of the data from the High Frequency Instrument (HFI) of the Planck mission will use several modules. Destriping is expected to play a central role in the mapmaking stage. This paper outlines two existing HFI l2 DPC destriping modules together with estimations of their performances. MOKAPIX is a temperature data destriping tool based on scanning redundancies on the sky. We have developped another modules, BOGOPIX , based on the same philosophy, to perform simultaneously destriping and relative intercalibration
The Intrinsic Fundamental Group of a Linear Category
We provide an intrinsic definition of the fundamental group of a linear
category over a ring as the automorphism group of the fibre functor on Galois
coverings. If the universal covering exists, we prove that this group is
isomorphic to the Galois group of the universal covering. The grading deduced
from a Galois covering enables us to describe the canonical monomorphism from
its automorphism group to the first Hochschild-Mitchell cohomology vector
space.Comment: Final version, to appear in Algebras and Representation Theor
The 2mrad crossing angle scheme for the international linear collider
http://cern.ch/AccelConf/e08/papers/mopp005.pdfInternational audienceThe present baseline conïŹguration of the ILC has a 14 mrad crossing angle between the beams at the interaction point. This allows easier extraction of the beams after col- lisions, but imposes on the other hand more constraints on the control of the beams prior to colliding them. More- over, some limitations to physics capabilities arise, in par- ticular because of the degraded very forward electromag- netic detector hermeticity and because calibration proce- dures for (gaseous) tracking detectors become more com- plex. To mitigate these problems, alternative conïŹgurations with very small crossing angles are studied. A new version of the 2 mrad layout was designed last year, based on sim- pler concepts and assumptions. The emphasis of this new scheme was to satisfy speciïŹcations with as few and feasi- ble magnets as possible, in order to reduce costs
Effect of the non-linear magnetic fields on the emittance growth in the ATF extraction line
WE6PFP075International audienceSince several years, the vertical beam emittance measured in the Extraction Line (EXT) of the Accelerator Test Facility (ATF) at KEK, has been signiïŹcantly larger than that measured in the damping ring (DR) itself. The EXT line that transports the beam to the ATF2 Final Focus beam line has been rebuilt, but the extraction itself remains in most part unchanged, with the extracted beam transported oïŹ- axis horizontally in two of the quadrupoles, beyond the linear region for one of them. A few other nearby magnets have also modelled or measured non-linearity. In case of a residual vertical beam displacement, this can result in increased vertical emittance through coupling between the two transverse planes. Tracking studies as well as measurements have been carried out to study this eïŹect and the induced sensitivity of beam optical parameters to the trajectory at injection, in view of deriving tolerances for reproducible and stable operation
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