638 research outputs found
The CERN Detector Safety System for the LHC Experiments
The Detector Safety System (DSS), currently being developed at CERN under the
auspices of the Joint Controls Project (JCOP), will be responsible for assuring
the protection of equipment for the four LHC experiments. Thus, the DSS will
require a high degree of both availability and reliability. After evaluation of
various possible solutions, a prototype is being built based on a redundant
Siemens PLC front-end, to which the safety-critical part of the DSS task is
delegated. This is then supervised by a PVSS SCADA system via an OPC server.
The PLC front-end is capable of running autonomously and of automatically
taking predefined protective actions whenever required. The supervisory layer
provides the operator with a status display and with limited online
reconfiguration capabilities. Configuration of the code running in the PLCs
will be completely data driven via the contents of a "Configuration Database".
Thus, the DSS can easily adapt to the different and constantly evolving
requirements of the LHC experiments during their construction, commissioning
and exploitation phases.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics
(CHEP03), La Jolla, Ca, USA, March 2003, 5 pages, PDF. PSN THGT00
Localization and superconducting proximity effect in sandwiched potassium films
Thin films of alkali metals when sandwiched at both surfaces by thin metal
films loose their conductance. The superconducting proximity effect is used to
investigate the change in the alkali film. On the length scale of the film
thickness the electronic properties of the alkali film do not change noticeably
although its conductance is dramatically reduced, corresponding to localized
electrons.Comment: 13 pages, 5 figure
Complex magnetism of lanthanide intermetallics unravelled
We explain a profound complexity of magnetic interactions of some
technologically relevant gadolinium intermetallics using an ab-initio
electronic structure theory which includes disordered local moments and strong
-electron correlations. The theory correctly finds GdZn and GdCd to be
simple ferromagnets and predicts a remarkably large increase of Curie
temperature with pressure of +1.5 K kbar for GdCd confirmed by our
experimental measurements of +1.6 K kbar. Moreover we find the origin of
a ferromagnetic-antiferromagnetic competition in GdMg manifested by
non-collinear, canted magnetic order at low temperatures. Replacing 35\% of the
Mg atoms with Zn removes this transition in excellent agreement with
longstanding experimental data.Comment: 11 pages, 4 figure
Minimally Invasive UltrasoundâGuided Carpal Tunnel Release: Preliminary Clinical Results
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146278/1/jum14618.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146278/2/jum14618_am.pd
The Superconducting Proximity Effect as a Tool to Investigate Metal Films and Interfaces
052The superconducting
proximity effect is measured in sandwiches of thin Pb films and the alkali
metals Cs, Rb, K and Na. The -dependence provides information about the
interface barriers between Pb and the alkalis. Such a barrier is particularly
large in Pb/Cs sandwiches. It is not due to impurities or oxydation. In the
presence of a sufficiently strong barrier a special form of the Cooper limit
can be applied to calculate the transition temperature of the sandwich
Transcriptome-Stable Isotope Probing Provides Targeted Functional and Taxonomic Insights Into Microaerobic Pollutant-Degrading Aquifer Microbiota
While most studies using RNA-stable isotope probing (SIP) to date have focused on ribosomal RNA, the detection of 13C-labeled mRNA has rarely been demonstrated. This approach could alleviate some of the major caveats of current non-target environmental âomics.â Here, we demonstrate the feasibility of total RNA-SIP in an experiment where hydrocarbon-degrading microbes from a BTEX-contaminated aquifer were studied in microcosms with 13C-labeled toluene under microoxic conditions. From the total sequencing reads (âź30 mio. reads per density-resolved RNA fraction), an average of 1.2% of reads per sample were identified as non-rRNA, including mRNA. Members of the Rhodocyclaceae (including those related to Quatrionicoccus spp.) were most abundant and enriched in 13C-rRNA, while well-known aerobic degraders such as Pseudomonas spp. remained unlabeled. Transcripts related to cell motility, secondary metabolite formation and xenobiotics degradation were highly labeled with 13C. mRNA of phenol hydroxylase genes were highly labeled and abundant, while other transcripts of toluene-activation were not detected. Clear labeling of catechol 2,3-dioxygenase transcripts supported previous findings that some of these extradiol dioxygenases were adapted to low oxygen concentrations. We introduce a novel combination of total RNA-SIP with calculation of transcript-specific enrichment factors (EFs) in 13C-RNA, enabling a targeted approach to process-relevant gene expression in complex microbiomes
Severe discrepancies between experiment and theory in the superconducting proximity effect
The superconducting proximity effect is investigated for SN double layers in
a regime where the resulting transition temperature T_{c} does not depend on
the mean free paths of the films and, within limits, not on the transparency of
the interface. This regime includes the thin film limit and the normalized
initial slope S_{sn}= (d_{s}/T_{s})|dT_{c}/dd_{n}|. The experimental results
for T_{c} are compared with a numerical simulation which was recently developed
in our group. The results for the SN double layers can be devided into three
groups: (i) When N = Cu, Ag, Au, Mg a disagreement between experiment and
theory by a factor of the order of three is observed, (ii) When N = Cd, Zn, Al
the disagreement between experiment and theory is reduced to a factor of about
1.5, (iii) When N = In, Sn a reasonably good agreement between experiment and
theory is observed
Quantum control of hybrid nuclear-electronic qubits
Pulsed magnetic resonance is a wide-reaching technology allowing the quantum
state of electronic and nuclear spins to be controlled on the timescale of
nanoseconds and microseconds respectively. The time required to flip either
dilute electronic or nuclear spins is orders of magnitude shorter than their
decoherence times, leading to several schemes for quantum information
processing with spin qubits. We investigate instead the novel regime where the
eigenstates approximate 50:50 superpositions of the electronic and nuclear spin
states forming "hybrid nuclear-electronic" qubits. Here we demonstrate quantum
control of these states for the first time, using bismuth-doped silicon, in
just 32 ns: this is orders of magnitude faster than previous experiments where
pure nuclear states were used. The coherence times of our states are five
orders of magnitude longer, reaching 4 ms, and are limited by the
naturally-occurring 29Si nuclear spin impurities. There is quantitative
agreement between our experiments and no-free-parameter analytical theory for
the resonance positions, as well as their relative intensities and relative
Rabi oscillation frequencies. In experiments where the slow manipulation of
some of the qubits is the rate limiting step, quantum computations would
benefit from faster operation in the hybrid regime.Comment: 20 pages, 8 figures, new data and simulation
Genome analysis provides insights into microaerobic toluene-degradation pathway of Zoogloea oleivorans BucT
Zoogloea oleivorans, capable of using toluene as a sole source of carbon and energy, was earlier found to be an active degrader under microaerobic conditions in aquifer samples. To uncover the genetic background of the ability of microaerobic toluene degradation in Z. oleivorans, the whole-genome sequence of the type strain Buc(T) was revealed. Metatranscriptomic sequence reads, originated from a previous SIP study on microaerobic toluene degradation, were mapped on the genome. The genome (5.68 Mb) had a mean G + C content of 62.5%, 5005 protein coding gene sequences and 80 RNA genes. Annotation predicted that 66 genes were involved in the metabolism of aromatic compounds. Genome analysis revealed the presence of a cluster with genes coding for a multicomponent phenol-hydroxylase system and a complete catechol meta-cleavage pathway. Another cluster flanked by mobile-element protein coding genes coded a partial catechol meta-cleavage pathway including a subfamily I.2.C-type extradiol dioxygenase. Analysis of metatranscriptomic data of a microaerobic toluene-degrading enrichment, containing Z . oleivorans as an active-toluene degrader revealed that a toluene dioxygenase-like enzyme was responsible for the ring-hydroxylation, while enzymes of the partial catechol meta-cleavage pathway coding cluster were responsible for further degradation of the aromatic ring under microaerobic conditions. This further advances our understanding of aromatic hydrocarbon degradation between fully oxic and strictly anoxic conditions
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