315 research outputs found
Automatic Gaze Classification for Aviators: Using Multi-task Convolutional Networks as a Proxy for Flight Instructor Observation
In this work, we investigate how flight instructors observe aviator scan patterns and assign quality to an aviator\u27s gaze. We first establish the reliability of instructors to assign similar quality to an aviator\u27s scan patterns, and then investigate methods to automate this quality using machine learning. In particular, we focus on the classification of gaze for aviators in a mixed-reality flight simulation. We create and evaluate two machine learning models for classifying gaze quality of aviators: a task-agnostic model and a multi-task model. Both models use deep convolutional neural networks to classify the quality of pilot gaze patterns for 40 pilots, operators, and novices, as compared to visual inspection by three experienced flight instructors. Our multi-task model can automate the process of gaze inspection with an average accuracy of over 93.0% for three separate flight tasks. Our approach could assist existing flight instructors to provide feedback to learners, or it could open the door to more automated feedback for pilots learning to carry out different maneuvers
Calculation of energy levels and transition amplitudes for barium and radium
The radium atom is a promising system for studying parity and time invariance
violating weak interactions. However, available experimental spectroscopic data
for radium is insufficient for designing an optimal experimental setup. We
calculate the energy levels and transition amplitudes for radium states of
significant interest. Forty states corresponding to all possible configurations
consisting of the , and single-electron states as well as the
states of the , and configurations have been calculated.
The energies of ten of these states corresponding to the , ,
, and configurations are not known from experiment. Calculations
for barium are used to control the accuracy.Comment: 12 pages, 4 table
Monte Carlo evaluation of the external gamma, neutron and muon induced background sources in the CUORE experiment
CUORE is a 1 ton scale cryogenic experiment aiming at the measurement of the
Majorana mass of the electron neutrino. The detector is an array of 988 TeO2
bolometers used for a calorimetric detection of the two electrons emitted in
the BB0n of 130Te. The sensitivity of the experiment to the lowest Majorana
mass is determined by the rate of background events that can mimic a BB0n. In
this paper we investigate the contribution of external sources i.e.
environmental gammas, neutrons and cosmic ray muons to the CUORE background and
show that the shielding setup designed for CUORE guarantees a reduction of this
external background down to a level <1.0E-02 c/keV/kg/y at the Q-value, as
required by the physical goal of the experiment.Comment: 14 pages, 7 figure
Double-beta decay Q values of 130Te, 128Te, and 120Te
The double-beta decay Q values of 130Te, 128Te, and 120Te have been
determined from parent-daughter mass differences measured with the Canadian
Penning Trap mass spectrometer. The 132Xe-129Xe mass difference, which is
precisely known, was also determined to confirm the accuracy of these results.
The 130Te Q value was found to be 2527.01(32) keV which is 3.3 keV lower than
the 2003 Atomic Mass Evaluation recommended value, but in agreement with the
most precise previous measurement. The uncertainty has been reduced by a factor
of 6 and is now significantly smaller than the resolution achieved or foreseen
in experimental searches for neutrinoless double-beta decay. The 128Te and
120Te Q values were found to be 865.87(131) keV and 1714.81(125) keV,
respectively. For 120Te, this reduction in uncertainty of nearly a factor of 8
opens up the possibility of using this isotope for sensitive searches for
neutrinoless double-electron capture and electron capture with positron
emission.Comment: 5 pages, 2 figures, submitted to Physical Review Letter
Wnt5a induces ROR1 to complex with HS1 to enhance migration of chronic lymphocytic leukemia cells.
ROR1 (receptor tyrosine kinase-like orphan receptor 1) is a conserved, oncoembryonic surface antigen expressed in chronic lymphocytic leukemia (CLL). We found that ROR1 associates with hematopoietic-lineage-cell-specific protein 1 (HS1) in freshly isolated CLL cells or in CLL cells cultured with exogenous Wnt5a. Wnt5a also induced HS1 tyrosine phosphorylation, recruitment of ARHGEF1, activation of RhoA and enhanced chemokine-directed migration; such effects could be inhibited by cirmtuzumab, a humanized anti-ROR1 mAb. We generated truncated forms of ROR1 and found its extracellular cysteine-rich domain or kringle domain was necessary for Wnt5a-induced HS1 phosphorylation. Moreover, the cytoplamic, and more specifically the proline-rich domain (PRD), of ROR1 was required for it to associate with HS1 and allow for F-actin polymerization in response to Wnt5a. Accordingly, we introduced single amino acid substitutions of proline (P) to alanine (A) in the ROR1 PRD at positions 784, 808, 826, 841 or 850 in potential SH3-binding motifs. In contrast to wild-type ROR1, or other ROR1P→︀A mutants, ROR1P(841)A had impaired capacity to recruit HS1 and ARHGEF1 to ROR1 in response to Wnt5a. Moreover, Wnt5a could not induce cells expressing ROR1P(841)A to phosphorylate HS1 or activate ARHGEF1, and was unable to enhance CLL-cell motility. Collectively, these studies indicate HS1 plays an important role in ROR1-dependent Wnt5a-enhanced chemokine-directed leukemia-cell migration
Beta-delayed-neutron studies of Sb and I performed with trapped ions
Beta-delayed-neutron (n) spectroscopy was performed using the
Beta-decay Paul Trap and an array of radiation detectors. The n
branching ratios and energy spectra for Sb and I were
obtained by measuring the time of flight of recoil ions emerging from the
trapped ion cloud. These nuclei are located at the edge of an isotopic region
identified as having n branching ratios that impact the r-process
abundance pattern around the A~130 peak. For Sb and I,
n branching ratios of 14.6(11)%, 17.6(28)%, and 7.6(28)% were
determined, respectively. The n energy spectra obtained for Sb
and I are compared with results from direct neutron measurements, and
the n energy spectrum for Sb has been measured for the first
time
To the Continuum and Beyond: Structure of U Nuclei
An experiment was performed at the 88-inch cyclotron at LBNL to investigate the structure of uranium isotopes and concurrently test the so-called surrogate ratio method. A 28 MeV proton beam was used to bombard 236U and 238U targets and the outgoing light ions were detected using the STARS silicon telescope allowing isotopic assignments and the excitation energy of the compound nucleus to be measured. A fission detector was placed at backward angles to give particle-fission coincidences, while the six clover germanium detectors of the LIBERACE array were used for particle-γ coincidences. The (p,d) reaction channels on 236U and 238U targets were used as a surrogate to measure the σ(234U(n,f))/σ(236U(n,f)) cross section ratio. The results give reasonable agreement with literature values over an equivalent neutron energy range between 0 MeV and 6 MeV. Structure results in 235U include a new (3/2−) level at 1035 keV, that is tentatively assigned as the 3/2−[501] Nilsson state. The analogue 3/2−[501] state in 237U may be associated with a previously observed level at 1201 keV, whose spin/parity is restricted to Jπ = 3/2− on the basis of newly observed decays to the ground band
Double-beta decay of Te to the first 0 excited state of Xe with CUORICINO
The CUORICINO experiment was an array of 62 TeO single-crystal
bolometers with a total Te mass of kg. The experiment finished
in 2008 after more than 3 years of active operating time. Searches for both
and double-beta decay to the first excited state in
Xe were performed by studying different coincidence scenarios. The
analysis was based on data representing a total exposure of
N(Te)t=y. No evidence for a signal was
found. The resulting lower limits on the half lives are y (90% C.L.), and
y (90%
C.L.).Comment: 6 pages, 4 figure
Utilizing (\u3cem\u3ep,d\u3c/em\u3e) and (\u3cem\u3ep,t\u3c/em\u3e) Reactions to Obtain (\u3cem\u3en,f\u3c/em\u3e) Cross Sections in Uranium Nuclei Via the Surrogate-Ratio Method
The surrogate ratio method has been tested for (p,d) and (p,t) reactions on uranium nuclei. 236U and 238U targets were bombarded with 28-MeV protons and the light ion recoils and fission fragments were detected using the Silicon Telescope Array for Reaction Studies detector array at the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory. The (p,df) reaction channels on 236U and 238U targets were used as a surrogate to determine the σ[236U(n,f)]/σ[234U(n,f)] cross-section ratio. The (p,tf) reaction channels were also measured with the same targets as a surrogate for the σ[235U(n,f)]/σ[(233U(n,f)] ratio. For the (p,df) and (p,tf) surrogate measurements, there is good agreement with accepted (n,f) values over equivalent neutron energy ranges of En=0–7 MeV and En=0–5.5 MeV, respectively. An internal surrogate ratio method comparing the (p,d) and (p,t) reaction channels on a single target is also discussed. The σ[234U(n,f)]/σ[233U(n,f)] and σ[236U(n,f)]/σ[235U(n,f)] cross-section ratios are extracted using this method for the 236U and 238U targets, respectively. The resulting fission cross-section ratios show relatively good agreement with accepted values up to En∼5 MeV
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