3,069 research outputs found
The hyperon mean free paths in the relativistic mean field
The - and -hyperon mean free paths in nuclei are firstly
calculated in the relativistic mean field (RMF) theory. The real parts of the
optical potential are derived from the RMF approach, while the imaginary parts
are obtained from those of nucleons with the relations:
and . With the
assumption, the depth of the imaginary potential for is
3.5 MeV, and for is 7 MeV at
low incident energy. We find that, the hyperon mean free path decreases with
the increase of the hyperon incident energies, from 200 MeV to 800 MeV; and in
the interior of the nuclei, the mean free path is about fm for
, and about fm for , depending on the hyperon
incident energy.Comment: 5 figures, 6 page
From the factory to the field: considerations of product characteristics for insecticide-treated net (ITN) bioefficacy testing
BACKGROUND: Insecticide-treated nets (ITNs) undergo a series of tests to obtain listing by World Health Organization (WHO) Prequalification. These tests characterize the bioefficacy, physical and chemical properties of the ITN. ITN procurers assume that product specifications relate to product performance. Here, ITN test methods and their underlying assumptions are discussed from the perspective of the ITN manufacturing process and product characteristics. METHODS: Data were extracted from WHO Pesticide Evaluation Scheme (WHOPES) meeting reports from 2003 to 2017, supplemented with additional chemical analysis to critically evaluate ITNs bioassays with a focus on sampling, washing and wash resistance, and bioefficacy testing. Production methods for ITNs and their impact on testing outcomes are described. RESULTS AND RECOMMENDATIONS: ITNs are not homogenous products. They vary within panels and between the sides and the roof. Running tests of wash resistance using a before/after tests on the same sample or band within a net reduces test variability. As mosquitoes frequently interact with ITN roofs, additional sampling of the roof when evaluating ITNs is advisable because in nets where roof and sides are of the same material, the contribution of roof sample (20-25%) to the average is less than the tolerance for the specification (25%). Mosquito mortality data cannot be reliably used to evaluate net surface concentration to determine regeneration time (RT) and resistance to washing as nets may regenerate beyond the insecticide concentrations needed to kill 100% of susceptible mosquitoes. Chemical assays to quantify surface concentration are needed. The Wash Resistance Index (WRI) averaged over the first four washes is only informative if the product has a log linear loss rate of insecticide. Using a WRI that excludes the first wash off gives more reliable results. Storage conditions used for product specifications are lower than those encountered under product shipping and storage that may exceed 50 degrees C, and should be reconsidered. Operational monitoring of new ITNs and linking observed product performance, such as bioefficacy after 2 or 3 years of use, with product characteristics, such as WRI, will aid the development of more robust test methods and product specifications for new products coming to market
Unconventional anomalous Hall effect in 3d/5d multilayers mediated by the nonlocal spin-conductivity
We evidenced unconventionnal Anomalous Hall Effects (AHE) in 3d/5d
(Co0.2nm/Ni0.6nm)N multilayers grown on a thin Pt layer or thin Au:W alloy. The
inversion observed on AHE originates from the opposite sign of the spin-orbit
coupling of Pt compared to Ni. Via advanced simulations methods for the
description of the spin-current profiles based on the spin-dependent Boltzmann
formalism, we extracted the spin Hall angle (SHA) of Pt and (Co/Ni) as well as
the relevant transport parameters. The extracted SHA for Pt, +20%, is opposite
to the one of (Co/Ni), giving rise to an effective AHE inversion for thin
(Co/Ni) multilayers (N < 17). The spin Hall angle in Pt is found to be larger
than the one previously measured in combined spin-pumping inverse spin-Hall
effect experiments in a geometry of current perpendicular to plane. Whereas
magnetic proximity effects cannot explain the effect, spin-current leakage and
anisotropic electron scattering at Pt/(Co,Ni) interfaces fit the experiments.Comment: 7 pages, 2 figure
Effect of Wine Closures on the Aroma Properties of Chardonnay Wines after Four Years of Storage
The effects of wine closures on the sensory properties and aroma profiles of fresh Chardonnay wines wereevaluated after four years of bottle storage. Natural cork closure, technical cork closure, Nomacorc light,Nomacorc classic and Nomacorc premium were investigated. Among these wines sealing with differentclosures, the physicochemical parameters of the wine samples showed no significant differences, exceptthat of the free and total sulphur dioxide. Nomacorc light with the highest OTR (oxygen transition rate)had the least residual free sulphur dioxide. Most of volatiles were generally stable, and seven compounds(acetoin, 1-butanol, 2-phenylethanol, 1-pentanol, (Z)-3-hexen-1-ol, 2-nonanol and ethyl decanoate) weresignificantly affected by the wine closures. The sensory analysis revealed that cork closures preserved morefruity/flowery characters of the fresh wines after four years’ storage, as well as cork-tainted off-flavour.Two synthetic closures (Nomacorc light, Nomacorc classic) imparted some grilled attributes to the wines.Nomacorc premium highly reserved the fruity/flowery flavour without cork contamination or oxidisedtoasted characters
Preparation and Foliar Application of Oligochitosan - Nanosilica on the Enhancement of Soybean Seed Yield
Oligochitosan with weight average molecu-lar weight (Mw) of 5000 g/mol was prepared by gamma Co-60 radiation degradation of 4% chitosan solution containing 0.5% H2O2 at 21 kGy. Nanosilica with size of 10 – 30 nm was synthesized by calcination of acid treated rice husk at 700o C for 2 h. The mixture of 2% oligo-chitosan-2% nanosilica was prepared by dispersion of nanosilica in oligochitosan solution. Oligochitosan, nanosilica and their mixture were characterized by gel permeation chromatography (GPC), transmission electr-on microscopy (TEM), X-ray diffraction (XRD), energy dispersive x-ray spectroscopy (EDX), Ultraviolet-visible spectroscopy (UV-Vis), and Furrier transform infrared spectroscopy (FT-IR). Effect of foliar application of oli-gochitosan and oligochitosan-nanosilica on soybean seed yield was conducted in experimental field. Results indi-cated that soybean seed yield increased 10.5 and 17.0% for oligochitosan and oligochitosan-nanosilica, respect-tively for the control. Radiation degraded oligo-chitosan and its mixture with nanosilica can be potentially used for cultivation of soybean with enhanced seed yield
Competing magnetic fluctuations in Sr3Ru2O7 probed by Ti doping
We report the effect of nonmagnetic Ti4+ impurities on the electronic and
magnetic properties of Sr3Ru2O7. Small amounts of Ti suppress the
characteristic peak in magnetic susceptibility near 16 K and result in a sharp
upturn in specific heat. The metamagnetic quantum phase transition and related
anomalous features are quickly smeared out by small amounts of Ti. These
results provide strong evidence for the existence of competing magnetic
fluctuations in the ground state of Sr3Ru2O7. Ti doping suppresses the low
temperature antiferromagnetic interactions that arise from Fermi surface
nesting, leaving the system in a state dominated by ferromagnetic fluctuations.Comment: 5 pages, 4 figures, 1 tabl
Class based Influence Functions for Error Detection
Influence functions (IFs) are a powerful tool for detecting anomalous
examples in large scale datasets. However, they are unstable when applied to
deep networks. In this paper, we provide an explanation for the instability of
IFs and develop a solution to this problem. We show that IFs are unreliable
when the two data points belong to two different classes. Our solution
leverages class information to improve the stability of IFs. Extensive
experiments show that our modification significantly improves the performance
and stability of IFs while incurring no additional computational cost.Comment: Thang Nguyen-Duc, Hoang Thanh-Tung, and Quan Hung Tran are co-first
authors of this paper. 12 pages, 12 figures. Accepted to ACL 202
Recommended from our members
Reaction, process, and cost engineering for the flash hydropyrolysis (FHP) of coal
The latest experimental data on the Flash Hydropyrolysis of North Dakota lignite in the 2 lb/hr entrained tubular reactor experimental facility are summarized. The range of conditions investigated covers reactor pressures from 500 psi to 4000 psi, temperatures from 500/sup 0/ to 900/sup 0/C, and coal particle residence times in the reactor from 1 to 10 seconds. The major effects of the process variables on the yields of liquid hydrocarbons consisting mainly of BTX and heavy oils (>= C/sub 9/) and hydrocarbon gases consisting mainly of methane and ethane and small amounts of carbon oxides are summarized. The product yield for maximum carbon conversion to liquid was obtained at 725/sup 0/C and 2000 psi and amounts to 10% BTX, 10% oils, 25% methane, 10% ethane, and 6% CO. A maximum gaseous yield was obtained at 875/sup 0/C and 2500 psi and amounts to 88% methane, 0.5% ethane, 1.3% CO and < 1% BTX. The FHP process has the advantage of allowing effective gas-solid and gas-liquid separation operations for producing hydrocarbon products from the unconverted char, oils, and process gas. The FHP system also has the distinct advantage of versatility and process flexibility for varying the product slate and the production rate of gaseous and liquid hydrocarbon fuel products in the same reactor depending on reactor operating conditions
Scalar ground-state observables in the random phase approximation
We calculate the ground-state expectation value of scalar observables in the
matrix formulation of the random phase approximation (RPA). Our expression,
derived using the quasiboson approximation, is a straightforward generalization
of the RPA correlation energy. We test the reliability of our expression by
comparing against full diagonalization in 0 h-bar omega shell-model spaces. In
general the RPA values are an improvement over mean-field (Hartree-Fock)
results, but are not always consistent with shell-model results. We also
consider exact symmetries broken in the mean-field state and whether or not
they are restored in RPA.Comment: 7 pages, 3 figure
Detection of strong scattering close to the eclipse region of PSR B1957+20
We present the first measurement of pulse scattering close to the eclipse
region of PSR B1957+20, which is in a compact binary system with a low-mass
star. We measured pulse scattering time-scales up to 0.2 ms close to the
eclipse and showed that it scales with the dispersion measure (DM) excess
roughly as . Our observations provide the first
evidence of strong scattering due to multi-path propagation effects in the
eclipsing material. We show that Kolmogorov turbulence in the eclipsing
material with an inner scale of m and an outer scale of the size of
the eclipse region can naturally explain the observation. Our results show that
the eclipsing material in such systems can be highly turbulent and suggest that
scattering is one of the main eclipsing mechanisms at around 1.4 GHz.Comment: 8 pages, 4 figures, MNRAS accepte
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