390 research outputs found
Accounting for preemption and migration costs in the calculation of hard real-time cyclic executives for MPSoCs
This work introduces a methodology to consider preemption and migration overhead in hard real-time cyclic executives on multicore architectures. The approach performs two iterative stages. The first stage takes a cyclic executive, from which the number and timing of all preemptions and migrations for every task is known. Then, it includes this overhead by updating the worst-case execution time (WCET) of the tasks. The second stage calculates a new cyclic executive considering the new WCET of tasks. The stages iterate until the preemption and migration overhead keeps constant. © 2016 IEEE
Systematic trends in beta-delayed particle emitting nuclei: The case of beta-p-alpha emission from 21Mg
We have observed beta+-delayed alpha and p-alpha emission from the
proton-rich nucleus 21Mg produced at the ISOLDE facility at CERN. The
assignments were cross-checked with a time distribution analysis. This is the
third identified case of beta-p-alpha emission. We discuss the systematic of
beta-delayed particle emission decays, show that our observed decays fit
naturally into the existing pattern, and argue that the patterns are to a large
extent caused by odd-even effects.Comment: 6 pages, 5 figure
Shapes of the Pb ground states from beta decay studies using the total absorption technique
The beta decay of Pb has been studied using the total absorption
technique at the ISOLDE(CERN) facility. The beta-decay strength deduced from
the measurements, combined with QRPA theoretical calculations, allow us to
infer that the ground states of the Pb isotopes are spherical.
These results represent the first application of the shape determination method
using the total absorption technique for heavy nuclei and in a region where
there is considerable interest in nuclear shapes and shape effects
Evaluation of saliency tracking as an alternative for health monitoring in PMSM-drives under nonstationary conditions
This paper evaluates the capability of saliency tracking to assess the health condition of permanent magnet synchronous motor (PMSM) drives operating under nonstationary conditions. The evaluated scheme is based on saliency tracking methods, which are associated to the accurate sensorless control of AC drives without zero speed limitations. In this work two representative saliency tracking architectures are evaluated: High Frequency (HF) injection, and PWM transient excitation. Although a monitoring approach based on HF injection was previously reported, a comparative study to evaluate the most representative saliency tracking schemes to assess health condition in drives was still missing. The aim of this work is to fill out this gap by evaluating and comparing two saliency-based monitoring schemes (one based on HF-injection and the other based on PWM transient excitation) to evaluate their performance in the presence of inter-turn winding faults.
Simulation and experimental results are presented which confirm that both schemes offer excellent detection capabilities and that are suitable for drives operating under nonstationary conditions including standstill operation. Significant differences are also found for instance, PWM transient excitation offers improved accuracy since the approach is not affected by the inverter nonlinearities and is suitable for full-speed range applications. The main drawback here is complexity and the hardware requirements. Schemes based on HF-injection proved to be very simple and provide comparable results; however a good performance is only guaranteed for the zero-to-medium speed range applications which limit their applicability
Proton radiographs using position-sensitive silicon detectors and high-resolution scintillators
Proton therapy is a cancer treatment technique currently in growth worldwide.
It offers advantages with respect to conventional X-ray and -ray
radiotherapy, in particular, a better control of the dose deposition allowing
to reach a higher conformity in the treatments. Therefore, it causes less
damage to the surrounding healthy tissue and less secondary effects. However,
in order to take full advantage of its potential, improvements in treatment
planning and dose verification are required. A new prototype of proton Computed
Tomography scanner is proposed to design more accurate and precise treatment
plans for proton therapy. Here, results obtained from an experiment performed
using a 100-MeV proton beam at the CCB facility in Krakow (Poland) are
presented. Proton radiographs of PMMA samples of 50-mm thickness with spatial
patterns in aluminum were taken. Their properties were studied, including
reproduction of the dimensions, spatial resolution and sensitivity to different
materials. They demonstrate the capabilities of the system to produce images
with protons. Structures of up to 2 mm are nicely resolved and the sensitivity
of the system was enough to distinguish thicknesses of 10 mm of aluminum or
PMMA. This constitutes a first step to validate the device as a proton
radiography scanner previous to the future tests as a proton CT scanner.Comment: 7 pages, 11 figures, submitted to IEEE TNS ANIMMA 2021 Conference
Proceeding
Beta-decay of Mn-65 to Fe-65
The low energy structure of Fe-65 has been studied by means of gamma- and
fast-timing spectroscopy. A level scheme of Fe-65 populated following the
beta-decay of Mn-65 was established for the first time. It includes 41 levels
and 85 transitions. The excitation energy of the beta-decaying isomer in Fe-65
has been precisely determined at 393.7(2) keV. The beta delayed neutron
emission branch was measured as Pn = 7.9(12)%, which cannot be reconciled with
the previously reported value of 21.0(5)%. Four gamma-rays and four excited
states in Fe-64 were identified as being populated following the beta-n decay.
Four lifetimes and five lifetime limits in the subnanosecond range have been
measured using the Advanced Time-Delayed Method. The level scheme is compared
with shell-model calculations. Tentative spin and parity assignments are
proposed based on the observed transition rates, the calculations and the
systematics of the region.Comment: Accepted in Physical Review
Estimation of the exposure for the air shower detection mode of EUSO-SPB1
EUSO-SPB1 was a balloon-borne pathfinder mission of the JEM-EUSO (Joint Experiment Missions for the Extreme Universe Space Observatory) program. A 12-day long flight started from New Zealand on April 25th, 2017 on-board the NASA's Super Pressure Balloon. With capability of detecting EeV energy air showers, the data acquisition was performed using a 1 m^2 two-Fresnel-lens UV-sensitive telescope with fast readout electronics in the air shower detection mode over ~30 hours at ~16--30 km above South Pacific. Using a variety of approaches, we searched for air shower events. Up to now, no air shower events have been identified. The effective exposure, regarding the role of the clouds in particular, was estimated based on the air shower and detector simulations together with a numerical weather forecast model. Compared with the case assuming the fully clear atmosphere conditions, more than ~60% of showers are detectable regardless the presence of the clouds. The studies in the present work will be applied in the follow-up pathfinders and in the future full-scale missions in the JEM-EUSO program
Impact of Liver Inflammation on Bile Acid Side Chain Shortening and Amidation
Bile acid (BA) synthesis from cholesterol by hepatocytes is inhibited by inflammatory cytokines. Whether liver inflammation also affects BA side chain shortening and conjugation was investigated. In human liver cell lines (IHH, HepG2, and HepaRG), agonists of nuclear receptors including the farnesoid X receptor (FXR), liver X receptor (LXR), and peroxisome proliferator-activated receptors (PPARs) did not affect the expression of BA-related peroxisomal enzymes. In contrast, hepatocyte nuclear factor 4? (HNF4?) inhibition down-regulated acyl-CoA oxidase 2 (ACOX2). ACOX2 was repressed by fibroblast growth factor 19 (FGF19), which was prevented by extracellular signal-regulated kinase (ERK) pathway inhibition. These changes were paralleled by altered BA synthesis (HPLC-MS/MS). Cytokines able to down-regulate cholesterol-7?-hydroxylase (CYP7A1) had little effect on peroxisomal enzymes involved in BA synthesis except for ACOX2 and bile acid-CoA:amino acid N-acyltransferase (BAAT), which were down-regulated, mainly by oncostatin M (OSM). This effect was prevented by Janus kinase (JAK) inhibition, which restored BA side chain shortening and conjugation. The binding of OSM to the extracellular matrix accounted for a persistent effect after culture medium replacement. In silico analysis of four databases (n = 201) and a validation cohort (n = 90) revealed an inverse relationship between liver inflammation and ACOX2/BAAT expression which was associated with changes in HNF4? levels. In conclusion, BA side chain shortening and conjugation are inhibited by inflammatory effectors. However, other mechanisms involved in BA homeostasis counterbalance any significant impact on the serum BA profile
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