1,624 research outputs found
Commissioning of the Beam Interlock System for the TT40 and TT41 Transfer Lines of the SPS
The extraction area of LSS4 in the SPS and the TT40 and TT41 transfer lines have been equipped with a new interlock system to protect the machine elements against beam induced failure during operation with the high intensity CNGS beams. The system commissioning that was performed during the 2006 SPS run followed pre-defined commissioning procedures. An extensive WEB based documentation of the tests has been established to track the state of the interlock system, in particular of interlock references. This document presents a short summary of the commissioning as well as the complete documentation of the interlock tests
Cosmological Consequences of String Axions
Axion fluctuations generated during inflation lead to isocurvature and
non-Gaussian temperature fluctuations in the cosmic microwave background
radiation. Following a previous analysis for the model independent string axion
we consider the consequences of a measurement of these fluctuations for two
additional string axions. We do so independent of any cosmological assumptions
except for the axions being massless during inflation. The first axion has been
shown to solve the strong CP problem for most compactifications of the
heterotic string while the second axion, which does not solve the strong CP
problem, obeys a mass formula which is independent of the axion scale. We find
that if gravitational waves interpreted as arising from inflation are observed
by the PLANCK polarimetry experiment with a Hubble constant during inflation of
H_inf \apprge 10^13 GeV the existence of the first axion is ruled out and the
second axion cannot obey the scale independent mass formula. In an appendix we
quantitatively justify the often held assumption that temperature corrections
to the zero temperature QCD axion mass may be ignored for temperatures T
\apprle \Lambda_QCD.Comment: 27 pages, 4 figures; v2: References corrected; v3: Assumptions
simplified, minor corrections, conclusions unchange
Cosmological Inhomogeneities with Bose-Einstein Condensate Dark Matter
We consider the growth of cosmological perturbations to the energy density of
dark matter during matter domination when dark matter is a scalar field that
has undergone Bose-Einstein condensation. We study these inhomogeneities within
the framework of both Newtonian gravity, where the calculation and results are
more transparent, and General Relativity. The direction we take is to derive
analytical expressions, which can be obtained in the small pressure limit.
Throughout we compare our results to those of the standard cosmology, where
dark matter is assumed pressureless, using our analytical expressions to
showcase precise differences. We find, compared to the standard cosmology, that
Bose-Einstein condensate dark matter leads to a scale factor, gravitational
potential and density contrast that increase at faster rates.Comment: 17 pages, 2 figures; typos corrected, references adde
Superconductor-insulator transition in granular Pb films near a superconducting ground plane
We report observations of the zero-field superconductor-insulator transition in granular quench-condensed Pb for samples within 10-15 nm of relatively thick superconducting ground planes. Resistance vs temperature measurements of sufficiently thick Pb samples exhibit broadened superconductor transitions consistent with previous results on clean dielectric substrates. The lack of any measurable influence by the superconducting planes on the Pb film resistance is discussed within the context of zero-field vortex-antivortex unbinding explanations for the transition broadening
Determination of the Chromaticity of the TI 8 Transfer Line Based on Kick Response Measurements
The 3 km long TI 8 transfer line is used to transfer 450 GeV proton and ion beams from the SPS to LHC collider. As part of a detailed optics investigation program the chromaticity of the transfer line was measured. Kick response data of the transfer line was recorded for various extraction energy offsets in the SPS. The quadrupolar and sextupolar field errors (b2 and b3, respectively) over the whole transfer line dipoles, a systematic error of the main quadrupole strengths and the initial momentum error were estimated by a fit. Using the updated model, the chromaticity of the line was then calculated
The LHC Sector Test
The proposal to inject beam into a sector of the partially completed LHC is presented. The test will provide an important milestone, force preparation of a number of key systems, and allow a number of critical measurements with beam. The motivation for the test is discussed, along with the proposed beam studies, the radiation issues and the potential impact on ongoing installation. The demands on the various accelerator systems implicated are presented along with the scheduling of the preparatory steps, the test itself and the recovery phase
(For all launch dates) Apollo 16 preliminary lunar surface procedures
This Preliminary Apollo 16 Lunar Surface Procedures document is used to document the planning for lunar surface EVA operations on Mission J-2, to describe the crew equipment interface, and to document the manner in which the lunar surface mission requirements are to be implemented.Prepared by: R. R. Kain, Lunar Surface Procedures Section, R. J. Koppa, General Electric Co., J. G. Olmsted, General Electric Co., T. O. Montgomery, General Electric Co.Prepared by Lunar Surface Procedures Section, EVA/IVA Procedures Branch, Crew Procedures DivisionIntroduction -- Mission description -- Nominal lunar surface EVA -- Contingent plans – Appendix
Adhesion of Escherichia coli under flow conditions reveals potential novel effects of FimH mutations
FimH-mediated adhesion of Escherichia coli to bladder epithelium is a prerequisite for urinary tract infections. FimH is also essential for blood-borne bacterial dissemination, but the mechanisms are poorly understood. The purpose of this study was to assess the influence of different FimH mutations on bacterial adhesion using a novel adhesion assay, which models the physiological flow conditions bacteria are exposed to. We introduced 12 different point mutations in the mannose binding pocket of FimH in an E. coli strain expressing type 1 fimbriae only (MSC95-FimH). We compared the bacterial adhesion of each mutant across several commonly used adhesion assays, including agglutination of yeast, adhesion to mono- and tri-mannosylated substrates, and static adhesion to bladder epithelial and endothelial cells. We performed a comparison of these assays to a novel method that we developed to study bacterial adhesion to mammalian cells under flow conditions. We showed that E. coli MSC95-FimH adheres more efficiently to microvascular endothelium than to bladder epithelium, and that only endothelium supports adhesion at physiological shear stress. The results confirmed that mannose binding pocket mutations abrogated adhesion. We demonstrated that FimH residues E50 and T53 are crucial for adhesion under flow conditions. The coating of endothelial cells on biochips and modelling of physiological flow conditions enabled us to identify FimH residues crucial for adhesion. These results provide novel insights into screening methods to determine the effect of FimH mutants and potentially FimH antagonists. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s10096-016-2820-8) contains supplementary material, which is available to authorized users
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