49 research outputs found
Modeling of the subgrid-scale term of the filtered magnetic field transport equation
Accurate subgrid-scale turbulence models are needed to perform realistic
numerical magnetohydrodynamic (MHD) simulations of the subsurface flows of the
Sun. To perform large-eddy simulations (LES) of turbulent MHD flows, three
unknown terms have to be modeled. As a first step, this work proposes to use a
priori tests to measure the accuracy of various models proposed to predict the
SGS term appearing in the transport equation of the filtered magnetic field. It
is proposed to evaluate the SGS model accuracy in term of "structural" and
"functional" performance, i.e. the model capacity to locally approximate the
unknown term and to reproduce its energetic action, respectively. From our
tests, it appears that a mixed model based on the scale-similarity model has
better performance.Comment: 10 pages, 5 figures; Center for Turbulence Research, Proceedings of
the Summer Program 2010, Stanford Universit
Measurement of the atmospheric muon charge ratio with the OPERA detector
The OPERA detector at the Gran Sasso underground laboratory (LNGS) was used
to measure the atmospheric muon charge ratio in the TeV energy region. We
analyzed 403069 atmospheric muons corresponding to 113.4 days of livetime
during the 2008 CNGS run. We computed separately the muon charge ratio for
single and for multiple muon events in order to select different energy regions
of the primary cosmic ray spectrum and to test the charge ratio dependence on
the primary composition. The measured charge ratio values were corrected taking
into account the charge-misidentification errors. Data have also been grouped
in five bins of the "vertical surface energy". A fit to a simplified model of
muon production in the atmosphere allowed the determination of the pion and
kaon charge ratios weighted by the cosmic ray energy spectrum.Comment: 14 pages, 10 figure
The detection of neutrino interactions in the emulsion/lead target of the OPERA experiment
The OPERA neutrino detector in the underground Gran Sasso Laboratory (LNGS)
was designed to perform the first detection of neutrino oscillations in
appearance mode through the study of oscillations. The
apparatus consists of an emulsion/lead target complemented by electronic
detectors and it is placed in the high energy long-baseline CERN to LNGS beam
(CNGS) 730 km away from the neutrino source. Runs with CNGS neutrinos were
successfully carried out in 2007 and 2008 with the detector fully operational
with its related facilities for the emulsion handling and analysis. After a
brief description of the beam and of the experimental setup we report on the
collection, reconstruction and analysis procedures of first samples of neutrino
interaction events
JUNO Conceptual Design Report
The Jiangmen Underground Neutrino Observatory (JUNO) is proposed to determine
the neutrino mass hierarchy using an underground liquid scintillator detector.
It is located 53 km away from both Yangjiang and Taishan Nuclear Power Plants
in Guangdong, China. The experimental hall, spanning more than 50 meters, is
under a granite mountain of over 700 m overburden. Within six years of running,
the detection of reactor antineutrinos can resolve the neutrino mass hierarchy
at a confidence level of 3-4, and determine neutrino oscillation
parameters , , and to
an accuracy of better than 1%. The JUNO detector can be also used to study
terrestrial and extra-terrestrial neutrinos and new physics beyond the Standard
Model. The central detector contains 20,000 tons liquid scintillator with an
acrylic sphere of 35 m in diameter. 17,000 508-mm diameter PMTs with high
quantum efficiency provide 75% optical coverage. The current choice of
the liquid scintillator is: linear alkyl benzene (LAB) as the solvent, plus PPO
as the scintillation fluor and a wavelength-shifter (Bis-MSB). The number of
detected photoelectrons per MeV is larger than 1,100 and the energy resolution
is expected to be 3% at 1 MeV. The calibration system is designed to deploy
multiple sources to cover the entire energy range of reactor antineutrinos, and
to achieve a full-volume position coverage inside the detector. The veto system
is used for muon detection, muon induced background study and reduction. It
consists of a Water Cherenkov detector and a Top Tracker system. The readout
system, the detector control system and the offline system insure efficient and
stable data acquisition and processing.Comment: 328 pages, 211 figure
THE TREATMENT OF COCCIDIOIDOMYCOSIS
SUMMARYTherapy of coccidioidomycosis continues to evolve. For primary pulmonary disease, antifungal therapy is frequently not required while prolonged courses of antifungals are generally needed for those in whom extrathoracic disseminated has occurred. Intravenous amphotericin B should be reserved for those with severe disease. Oral triazole antifungals have had a great impact on the management of coccidioidomycosis. Both fluconazole and itraconazole at 400 mg daily have been effective for various forms of coccidioidomycosis, including meningitis, although relapse after therapy is discontinued is a problem. Individuals with suppressed cellular immunity are at increased risk for symptomatic coccidioidomycosis and they include those with HIV infection, those on immunosuppressive medications, and those who have received a solid organ transplant. Pregnant women and African-American men have been identified as two other groups who are at an increased risk for symptomatic and severe infection
A review of bronchiolitis obliterans syndrome and therapeutic strategies
Lung transplantation is an important treatment option for patients with advanced lung disease. Survival rates for lung transplant recipients have improved; however, the major obstacle limiting better survival is bronchiolitis obliterans syndrome (BOS). In the last decade, survival after lung retransplantation has improved for transplant recipients with BOS. This manuscript reviews BOS along with the current therapeutic strategies, including recent outcomes for lung retransplantation
Heterologous Expression of Membrane Proteins: Choosing the Appropriate Host
International audienceBACKGROUND: Membrane proteins are the targets of 50% of drugs, although they only represent 1% of total cellular proteins. The first major bottleneck on the route to their functional and structural characterisation is their overexpression; and simply choosing the right system can involve many months of trial and error. This work is intended as a guide to where to start when faced with heterologous expression of a membrane protein. METHODOLOGY/PRINCIPAL FINDINGS: The expression of 20 membrane proteins, both peripheral and integral, in three prokaryotic (E. coli, L. lactis, R. sphaeroides) and three eukaryotic (A. thaliana, N. benthamiana, Sf9 insect cells) hosts was tested. The proteins tested were of various origins (bacteria, plants and mammals), functions (transporters, receptors, enzymes) and topologies (between 0 and 13 transmembrane segments). The Gateway system was used to clone all 20 genes into appropriate vectors for the hosts to be tested. Culture conditions were optimised for each host, and specific strategies were tested, such as the use of Mistic fusions in E. coli. 17 of the 20 proteins were produced at adequate yields for functional and, in some cases, structural studies. We have formulated general recommendations to assist with choosing an appropriate system based on our observations of protein behaviour in the different hosts. CONCLUSIONS/SIGNIFICANCE: Most of the methods presented here can be quite easily implemented in other laboratories. The results highlight certain factors that should be considered when selecting an expression host. The decision aide provided should help both newcomers and old-hands to select the best system for their favourite membrane protein
Observation of a first candidate in the OPERA experiment in the CNGS beam
The OPERA neutrino detector in the underground Gran Sasso Laboratory (LNGS)
has been designed to perform the first detection of neutrino oscillations in
direct appearance mode through the study of the
channel. The hybrid apparatus consists of an emulsion/lead target complemented
by electronic detectors and it is placed in the high energy long-baseline CERN
to LNGS beam (CNGS) 730 km away from the neutrino source. Runs with CNGS
neutrinos were successfully carried out in 2008 and 2009. After a brief
description of the beam, the experimental setup and the procedures used for the
analysis of the neutrino events, we describe the topology and kinematics of a
first candidate charged-current event satisfying the kinematical
selection criteria. The background calculations and their cross-check are
explained in detail and the significance of the event is assessed.Comment: 19 pages, 3 figure
Search for signatures of sterile neutrinos with Double Chooz
We present a search for signatures of neutrino mixing of electron
anti-neutrinos with additional hypothetical sterile neutrino flavors using the
Double Chooz experiment. The search is based on data from 5 years of operation
of Double Chooz, including 2 years in the two-detector configuration. The
analysis is based on a profile likelihood, i.e.\ comparing the data to the
model prediction of disappearance in a data-to-data comparison of the two
respective detectors. The analysis is optimized for a model of three active and
one sterile neutrino. It is sensitive in the typical mass range eV eV for
mixing angles down to . No significant
disappearance additionally to the conventional disappearance related to
is observed and correspondingly exclusion bounds on the sterile
mixing parameter as function of are
obtained.Comment: accepted for publication by EPJ
Reactor rate modulation oscillation analysis with two detectors in Double Chooz
A θ13 oscillation analysis based on the observed antineutrino rates at the Double Chooz far and near detectors for different reactor power conditions is presented. This approach provides a so far unique simultaneous determination of θ13 and the total background rates without relying on any assumptions on the specific background contributions. The analysis comprises 865 days of data collected in both detectors with at least one reactor in operation. The oscillation results are enhanced by the use of 24.06 days (12.74 days) of reactor-off data in the far (near) detector. The analysis considers the ν¯ e interactions up to a visible energy of 8.5 MeV, using the events at higher energies to build a cosmogenic background model considering fast-neutrons interactions and 9Li decays. The background-model-independent determination of the mixing angle yields sin2(2θ13) = 0.094 ± 0.017, being the best-fit total background rates fully consistent with the cosmogenic background model. A second oscillation analysis is also performed constraining the total background rates to the cosmogenic background estimates. While the central value is not significantly modified due to the consistency between the reactor-off data and the background estimates, the addition of the background model reduces the uncertainty on θ13 to 0.015. Along with the oscillation results, the normalization of the anti-neutrino rate is measured with a precision of 0.86%, reducing the 1.43% uncertainty associated to the expectation. [Figure not available: see fulltext.