155 research outputs found
Agroforestry systems of high natural and cultural value in Europe: structure, management, goods and services
info:eu-repo/semantics/publishedVersio
Measurement of the Multi-Neutron Charged Current Differential Cross Section at Low Available Energy on Hydrocarbon
Neutron production in antineutrino interactions can lead to bias in energy
reconstruction in neutrino oscillation experiments, but these interactions have
rarely been studied. MINERvA previously studied neutron production at an
average antineutrino energy of ~3 GeV in 2016 and found deficiencies in leading
models. In this paper, the MINERvA 6 GeV average antineutrino energy data set
is shown to have similar disagreements. A measurement of the cross section for
an antineutrino to produce two or more neutrons and have low visible energy is
presented as an experiment-independent way to explore neutron production
modeling. This cross section disagrees with several leading models'
predictions. Neutron modeling techniques from nuclear physics are used to
quantify neutron detection uncertainties on this result.Comment: 25 pages, 11 figures; Added ancillary files with cross section values
as .csv Matches preprint accepted by publishe
Simultaneous measurement of muon neutrino quasielastic-like cross sections on CH, C, water, Fe, and Pb as a function of muon kinematics at MINERvA
This paper presents the first simultaneous measurement of the
quasielastic-like neutrino-nucleus cross sections on C, water, Fe, Pb and
scintillator (hydrocarbon or CH) as a function of longitudinal and transverse
muon momentum. The ratio of cross sections per nucleon between Pb and CH is
always above unity and has a characteristic shape as a function of transverse
muon momentum that evolves slowly as a function of longitudinal muon momentum.
The ratio is constant versus longitudinal momentum within uncertainties above a
longitudinal momentum of 4.5GeV/c. The cross section ratios to CH for C, water,
and Fe remain roughly constant with increasing longitudinal momentum, and the
ratios between water or C to CH do not have any significant deviation from
unity. Both the overall cross section level and the shape for Pb and Fe as a
function of transverse muon momentum are not reproduced by current neutrino
event generators. These measurements provide a direct test of nuclear effects
in quasielastic-like interactions, which are major contributors to
long-baseline neutrino oscillation data samples.Comment: 9 pages, 8 flgures, including supplemental materia
Neutrino-induced coherent production in C, CH, Fe and Pb at GeV
MINERvA has measured the -induced coherent cross section
simultaneously in hydrocarbon (CH), graphite (C), iron (Fe) and lead (Pb)
targets using neutrinos from 2 to 20 GeV. The measurements exceed the
predictions of the Rein-Sehgal and Berger-Sehgal PCAC based models at multi-GeV
energies and at produced energies and angles,
GeV and . Measurements of the cross-section ratios of
Fe and Pb relative to CH reveal the effective -scaling to increase from an
approximate scaling at few GeV to an scaling for
GeV
Simultaneous measurement of muon neutrino charged-current single production in CH, C, HO, Fe, and Pb targets in MINERvA
Neutrino-induced charged-current single production in the
resonance region is of considerable interest to
accelerator-based neutrino oscillation experiments. In this work, high
statistics differential cross sections are reported for the semi-exclusive
reaction nucleon(s) on scintillator, carbon,
water, iron, and lead targets recorded by MINERvA using a wide-band
beam with \left \approx 6~GeV. Suppression of the cross
section at low and enhancement of low are observed in both light
and heavy nuclear targets compared to phenomenological models used in current
neutrino interaction generators. The cross-section ratios for iron and lead
compared to CH across the kinematic variables probed are 0.8 and 0.5
respectively, a scaling which is also not predicted by current generators.Comment: 6 pages, 6 figures, 117 pages of supplementary material; submitted to
Physical Review Letter
The Atacama Rover Astrobiology Drilling Studies (ARADS) Project
With advances in commercial space launch capabilities and reduced costs to orbit, humans may arrive on Mars within a decade. Both to preserve any signs of past (and extant) martian life and to protect the health of human crews (and Earth's biosphere), it will be necessary to assess the risk of cross-contamination on the surface, in blown dust, and into the near-subsurface (where exploration and resource-harvesting can be reasonably anticipated). Thus, evaluating for the presence of life and biosignatures may become a critical-path Mars exploration precursor in the not-so-far future, circa 2030. This Special Collection of papers from the Atacama Rover Astrobiology Drilling Studies (ARADS) project describes many of the scientific, technological, and operational issues associated with searching for and identifying biosignatures in an extreme hyperarid region in Chile's Atacama Desert, a well-studied terrestrial Mars analog environment. This paper provides an overview of the ARADS project and discusses in context the five other papers in the ARADS Special Collection, as well as prior ARADS project results.ARADS was a project under the auspices of the NASA Planetary Science and Technology Through Analog Research (NNH14ZDA001N-PSTAR) Program led by Dr. Mary Voytek. Support of the SOLID/LDChip instruments came from Grant No. RTI2018-094368-B-I00 (SOLID) and MDM-2017-0737 under the Unidad de Excelencia âMaria de Maeztuâ Centro de AstrobiologĂa (CSIC-INTA) program by the Spanish Ministry of Science and Innovation/State Agency of Research (MCIN/AEI/5 10.13039/501100011033) and also with support from âERDF: A way of making Europeâ. We are grateful for the support of Prof. Luis Caceres and students, and the kind use of the former research station facility at Estacion Yungay, supported with institutional resources of the University of Antofagasta.Peer reviewe
Assessment of plasma chitotriosidase activity, CCL18/PARC concentration and NP-C suspicion index in the diagnosis of Niemann-Pick disease type C: A prospective observational study
Background: Niemann-Pick disease type C (NP-C) is a rare, autosomal recessive neurodegenerative disease caused by mutations in either the NPC1 or NPC2 genes. The diagnosis of NP-C remains challenging due to the non-specific, heterogeneous nature of signs/symptoms. This study assessed the utility of plasma chitotriosidase (ChT) and Chemokine (C-C motif) ligand 18 (CCL18)/pulmonary and activation-regulated chemokine (PARC) in conjunction with the NP-C suspicion index (NP-C SI) for guiding confirmatory laboratory testing in patients with suspected NP-C. Methods: In a prospective observational cohort study, incorporating a retrospective determination of NP-C SI scores, two different diagnostic approaches were applied in two separate groups of unrelated patients from 51 Spanish medical centers (n = 118 in both groups). From Jan 2010 to Apr 2012 (Period 1), patients with =2 clinical signs/symptoms of NP-C were considered ''suspected NP-C'' cases, and NPC1/NPC2 sequencing, plasma chitotriosidase (ChT), CCL18/PARC and sphingomyelinase levels were assessed. Based on findings in Period 1, plasma ChT and CCL18/PARC, and NP-C SI prediction scores were determined in a second group of patients between May 2012 and Apr 2014 (Period 2), and NPC1 and NPC2 were sequenced only in those with elevated ChT and/or elevated CCL18/PARC and/or NP-C SI =70. Filipin staining and 7-ketocholesterol (7-KC) measurements were performed in all patients with NP-C gene mutations, where possible. Results: In total across Periods 1 and 2, 10/236 (4%) patients had a confirmed diagnosis o NP-C based on gene sequencing (5/118 4.2%] in each Period): all of these patients had two causal NPC1 mutations. Single mutant NPC1 alleles were detected in 8/236 (3%) patients, overall. Positive filipin staining results comprised three classical and five variant biochemical phenotypes. No NPC2 mutations were detected. All patients with NPC1 mutations had high ChT activity, high CCL18/PARC concentrations and/or NP-C SI scores =70. Plasma 7-KC was higher than control cut-off values in all patients with two NPC1 mutations, and in the majority of patients with single mutations. Family studies identified three further NP-C patients. Conclusion: This approach may be very useful for laboratories that do not have mass spectrometry facilities and therefore, they cannot use other NP-C biomarkers for diagnosis
Postoperative outcomes in oesophagectomy with trainee involvement
BACKGROUND: The complexity of oesophageal surgery and the significant risk of morbidity necessitates that oesophagectomy is predominantly performed by a consultant surgeon, or a senior trainee under their supervision. The aim of this study was to determine the impact of trainee involvement in oesophagectomy on postoperative outcomes in an international multicentre setting. METHODS: Data from the multicentre Oesophago-Gastric Anastomosis Study Group (OGAA) cohort study were analysed, which comprised prospectively collected data from patients undergoing oesophagectomy for oesophageal cancer between April 2018 and December 2018. Procedures were grouped by the level of trainee involvement, and univariable and multivariable analyses were performed to compare patient outcomes across groups. RESULTS: Of 2232 oesophagectomies from 137 centres in 41 countries, trainees were involved in 29.1 per cent of them (n = 650), performing only the abdominal phase in 230, only the chest and/or neck phases in 130, and all phases in 315 procedures. For procedures with a chest anastomosis, those with trainee involvement had similar 90-day mortality, complication and reoperation rates to consultant-performed oesophagectomies (P = 0.451, P = 0.318, and P = 0.382, respectively), while anastomotic leak rates were significantly lower in the trainee groups (P = 0.030). Procedures with a neck anastomosis had equivalent complication, anastomotic leak, and reoperation rates (P = 0.150, P = 0.430, and P = 0.632, respectively) in trainee-involved versus consultant-performed oesophagectomies, with significantly lower 90-day mortality in the trainee groups (P = 0.005). CONCLUSION: Trainee involvement was not found to be associated with significantly inferior postoperative outcomes for selected patients undergoing oesophagectomy. The results support continued supervised trainee involvement in oesophageal cancer surgery
Identification and reconstruction of low-energy electrons in the ProtoDUNE-SP detector
Measurements of electrons from interactions are crucial for the Deep
Underground Neutrino Experiment (DUNE) neutrino oscillation program, as well as
searches for physics beyond the standard model, supernova neutrino detection,
and solar neutrino measurements. This article describes the selection and
reconstruction of low-energy (Michel) electrons in the ProtoDUNE-SP detector.
ProtoDUNE-SP is one of the prototypes for the DUNE far detector, built and
operated at CERN as a charged particle test beam experiment. A sample of
low-energy electrons produced by the decay of cosmic muons is selected with a
purity of 95%. This sample is used to calibrate the low-energy electron energy
scale with two techniques. An electron energy calibration based on a cosmic ray
muon sample uses calibration constants derived from measured and simulated
cosmic ray muon events. Another calibration technique makes use of the
theoretically well-understood Michel electron energy spectrum to convert
reconstructed charge to electron energy. In addition, the effects of detector
response to low-energy electron energy scale and its resolution including
readout electronics threshold effects are quantified. Finally, the relation
between the theoretical and reconstructed low-energy electron energy spectrum
is derived and the energy resolution is characterized. The low-energy electron
selection presented here accounts for about 75% of the total electron deposited
energy. After the addition of lost energy using a Monte Carlo simulation, the
energy resolution improves from about 40% to 25% at 50~MeV. These results are
used to validate the expected capabilities of the DUNE far detector to
reconstruct low-energy electrons.Comment: 19 pages, 10 figure
Impact of cross-section uncertainties on supernova neutrino spectral parameter fitting in the Deep Underground Neutrino Experiment
A primary goal of the upcoming Deep Underground Neutrino Experiment (DUNE) is
to measure the MeV neutrinos produced by a Galactic
core-collapse supernova if one should occur during the lifetime of the
experiment. The liquid-argon-based detectors planned for DUNE are expected to
be uniquely sensitive to the component of the supernova flux, enabling
a wide variety of physics and astrophysics measurements. A key requirement for
a correct interpretation of these measurements is a good understanding of the
energy-dependent total cross section for charged-current
absorption on argon. In the context of a simulated extraction of
supernova spectral parameters from a toy analysis, we investigate the
impact of modeling uncertainties on DUNE's supernova neutrino
physics sensitivity for the first time. We find that the currently large
theoretical uncertainties on must be substantially reduced
before the flux parameters can be extracted reliably: in the absence of
external constraints, a measurement of the integrated neutrino luminosity with
less than 10\% bias with DUNE requires to be known to about 5%.
The neutrino spectral shape parameters can be known to better than 10% for a
20% uncertainty on the cross-section scale, although they will be sensitive to
uncertainties on the shape of . A direct measurement of
low-energy -argon scattering would be invaluable for improving the
theoretical precision to the needed level.Comment: 25 pages, 21 figure
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