244 research outputs found
New Working Conditions for the SPS from 2000
After the long shutdown (December 2000 to May 2001), the SPS complex will work with the main water-cooling loop in closed circuit. This will affect the working conditions because of the higher temperature of the supplied water (24 ° C, i.e. 15 K higher) and therefore of the air in the tunnel. The cooling installations will consequently be upgraded or replaced to meet the new needs, and several new chilled-water stations will be installed to supply the present users. The author will thoroughly explain the main aspects of all these modifications and report the results of the preliminary tests carried out in September 1996. Finally, an overview of the global costs (operational and linked to the project) will be given, taking into account the different consumption of water, electricity and the effects on the magnet components
Construction Progress of the Cooling and Ventilation in the LHC Project
The Cooling and Ventilation Group has started the LHC construction work in September 1999 and will get into full activity when LEP will be stopped and dismantled: in total 12 major contracts for an amount of about 120 MCHF will be established to build the needed installations for the LHC. The author will report on the current works that are in progress on the different LEP Points distinguishing between the Ventilation and the Water Cooling installations. The Ventilation work, completed in the new surface buildings in Points 18, is currently held in Points 4 and 5. Point 1 will follow in the near future. The work for the Cooling plants comprehend the pumping stations, the cooling towers and the chilled water production stations in Points 1 and 5, the buried pipes in Points 1 and 4. For all of these activities, an updated report of the progress of the work, of the planning and of the expenses is given. Finally, a short overview of the future activities is presented
Simulated natural lighting and constant 14-hour photoperiods for broiler breeders during the rearing period, and interactions of lighting with body weight
No Abstract. South African Journal of Animal Science Vol. 35 (1) 2005: pp.1-1
Consolidation on civil engineering and technical infrastructure
The use and age of the civil engineering structure (office buildings, halls, tunnels) and of tertiary technical equipment (mainly HVAC and electricity) at CERN is such that their renovation must be considered in the near future. Due to the large number of buildings and equipment in these conditions, and the restricted budget available it is extremely important to define priorities. The aim of this paper is to give an overview of the current conditions and the related problems, based on data analysis of CERN database and confronting it with the inventory made at CERN by an external company. After having identified the most frequent problems and repairs to carry out, a planning for intervention is therefore presented optimizing the safety aspects, maintenance costs and comfort for the users. The timescale of this intervention is related to the money that will be available in the coming years
Variability of serum markers of erythropoiesis during 6 days of racing in highly trained cyclists
The athlete biological passport for the fight against doping is currently based on longitudinal monitoring for abnormal changes in cellular blood parameters. Serum parameters related to altered erythropoiesis could be considered for inclusion in the passport. The aim of this study was to quantify the changes in such parameters in athletes during a period of intense exercise.
12 highly trained cyclists tapered for 3 days before 6 days of simulated intense stage racing. Morning and afternoon blood samples were taken on most days and analysed for total protein, albumin, soluble transferrin receptor and ferritin concentrations. Plasma volume was determined via total haemoglobin mass measured by carbon-monoxide rebreathing. Percent changes in means from baseline and percent standard errors of measurement (analytical error plus intra-athlete variation) on each measurement occasion were estimated with mixed linear modelling of log-transformed measures.
Means of all variables changed substantially in the days following the onset of racing, ranging from â13% (haemoglobin concentration) to +27% (ferritin). After the second day, errors of measurement were generally twice those at baseline.
Plasma variables were affected by heavy exercise, either because of changes in plasma volume (total protein, albumin, haemoglobin), acute phase/inflammatory reactions (ferritin) or both (soluble transferrin receptor). These effects need to be taken into consideration when integrating a plasma parameter into the biological passport model for athletes
The BTZ black hole with a time-dependent boundary
The non-rotating BTZ solution is expressed in terms of coordinates that allow
for an arbitrary time-dependent scale factor in the boundary metric. We provide
explicit expressions for the coordinate transformation that generates this form
of the metric, and determine the regions of the complete Penrose diagram that
are convered by our parametrization. This construction is utilized in order to
compute the stress-energy tensor of the dual CFT on a time-dependent
background. We study in detail the expansion of radial null geodesic
congruences in the BTZ background for various forms of the scale factor of the
boundary metric. We also discuss the relevance of our construction for the
holographic calculation of the entanglement entropy of the dual CFT on
time-dependent backgrounds.Comment: 14 pages, 13 figures, title changed in journal, conformal diagrams
added, references added, final version to appear in Classical and Quantum
Gravit
Entanglement Entropy from a Holographic Viewpoint
The entanglement entropy has been historically studied by many authors in
order to obtain quantum mechanical interpretations of the gravitational
entropy. The discovery of AdS/CFT correspondence leads to the idea of
holographic entanglement entropy, which is a clear solution to this important
problem in gravity. In this article, we would like to give a quick survey of
recent progresses on the holographic entanglement entropy. We focus on its
gravitational aspects, so that it is comprehensible to those who are familiar
with general relativity and basics of quantum field theory.Comment: Latex, 30 pages, invited review for Classical and Quantum Gravity,
minor correction
A primary electron beam facility at CERN -- eSPS Conceptual design report
The design of a primary electron beam facility at CERN is described. The
study has been carried out within the framework of the wider Physics Beyond
Colliders study. It re-enables the Super Proton Synchrotron (SPS) as an
electron accelerator, and leverages the development invested in Compact Linear
Collider (CLIC) technology for its injector and as an accelerator research and
development infrastructure. The facility would be relevant for several of the
key priorities in the 2020 update of the European Strategy for Particle
Physics, such as an electron-positron Higgs factory, accelerator R\&D, dark
sector physics, and neutrino physics. In addition, it could serve experiments
in nuclear physics. The electron beam delivered by this facility would provide
access to light dark matter production significantly beyond the targets
predicted by a thermal dark matter origin, and for natures of dark matter
particles that are not accessible by direct detection experiments. It would
also enable electro-nuclear measurements crucial for precise modelling the
energy dependence of neutrino-nucleus interactions, which is needed to
precisely measure neutrino oscillations as a function of energy. The
implementation of the facility is the natural next step in the development of
X-band high-gradient acceleration technology, a key technology for compact and
cost-effective electron/positron linacs. It would also become the only facility
with multi-GeV drive bunches and truly independent electron witness bunches for
plasma wakefield acceleration. A second phase capable to deliver positron
witness bunches would make it a complete facility for plasma wakefield collider
studies. [...
Team climate, intention to leave and turnover among hospital employees: Prospective cohort study
<p>Abstract</p> <p>Background</p> <p>In hospitals, the costs of employee turnover are substantial and intentions to leave among staff may manifest as lowered performance. We examined whether team climate, as indicated by clear and shared goals, participation, task orientation and support for innovation, predicts intention to leave the job and actual turnover among hospital employees.</p> <p>Methods</p> <p>Prospective study with baseline and follow-up surveys (2â4 years apart). The participants were 6,441 (785 men, 5,656 women) hospital employees under the age of 55 at the time of follow-up survey. Logistic regression with generalized estimating equations was used as an analysis method to include both individual and work unit level predictors in the models.</p> <p>Results</p> <p>Among stayers with no intention to leave at baseline, lower self-reported team climate predicted higher likelihood of having intentions to leave at follow-up (odds ratio per 1 standard deviation decrease in team climate was 1.6, 95% confidence interval 1.4â1.8). Lower co-worker assessed team climate at follow-up was also association with such intentions (odds ratio 1.8, 95% confidence interval 1.4â2.4). Among all participants, the likelihood of actually quitting the job was higher for those with poor self-reported team climate at baseline. This association disappeared after adjustment for intention to leave at baseline suggesting that such intentions may explain the greater turnover rate among employees with low team climate.</p> <p>Conclusion</p> <p>Improving team climate may reduce intentions to leave and turnover among hospital employees.</p
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