3,313 research outputs found
Photoinduced Surface Relief Grating Formation for a Single Crystal of 4-Aminoazobenzene
Photoinduced surface relief grating (SRG) formation for a single crystal of 4-aminoazobenzene was investigated. It was found that SRG could be inscribed on the (001) surface of the crystal, which might suggest that the photoinduced SRG formation is a general phenomenon observed for single crystals of azobenzene-based molecules as well as for azobenzene-based amorphous systems. In addition, the dependences of the SRG formation upon the orientation of the sample crystal and upon the polarization of the writing beams were found to be different from those observed for previously reported crystalline systems
Pre- and post-initiation modulating effects of green tea ingestion on rat hepatocarcinogenesis
The purpose of this study was to investigate the effects of green tea ingestion on hepatocarcinogenesis before and after its initiation. Male Sprague-Dawley rats were fed an AIN76A diet with or without green tea. Initiation was induced by a single dose (200 mg/kg) of diethylnitrosamine at week 4 and 0.02% (w/w) 2-acetylaminofluorene was supplied in the diets. The control group had free access to water for 13 weeks (CTR13). Tea infusion was provided from the beginning of the experiment for 13 weeks (PRE13) or from the post-initiation stage until week 13 (POST13). Three other groups (CTR24, PRE24 and POST24) were added to examine the longer-term effects (24 weeks) with the same experimental design. The percentage area of liver sections that were positive for hepatic placental glutathione S-transferase (GST-P), which was used as a marker of preneoplastic lesions, was smaller in PRE13 (20.2 ± 5.0%, mean ± SD) and POST13 (26.0 ± 4.8%) than in CTR13 (33.2 ± 5.8%, p<0.05). Over the longer period, the GST-P lesions were significantly smaller for both PRE24 and POST24 (21.6 ± 8.5% and 22.2 ± 4.0%, respectively) than for CTR24 (28.6 ± 5.1%, p<0.05), but there was no significant difference between PRE24 and POST24. The liver content of thiobarbituric acid reactive substances was significantly lower in the tea groups than in the controls (p<0.05). However, no significant differences were observed among groups of GST activity. The results show that tea consumption exhibits a stronger short-term initiation-inhibiting ability in liver carcinogenesis, but over a longer period, the preventive effects of green tea ingestion do not differ in post- and pre-initiation
First analysis of anisotropic flow with Lee--Yang zeroes
We report on the first analysis of directed and elliptic flow with the new
method of Lee--Yang zeroes. Experimental data are presented for Ru+Ru reactions
at 1.69 AGeV measured with the FOPI detector at SIS/GSI. The results obtained
with several methods, based on the event-plane reconstruction, on Lee--Yang
zeroes, and on multi-particle cumulants (up to 5th order) applied for the first
time at SIS energies, are compared. They show conclusive evidence that
azimuthal correlations between nucleons and composite particles at this energy
are largely dominated by anisotropic flow.Comment: 5 pages, 3 figures, submitted to Phys. Rev. C Rapid Co
Isospin dependence of relative yields of and mesons at 1.528 AGeV
Results on and meson production in Ru +
Ru and Zr + Zr collisions at a beam kinetic
energy of 1.528 GeV, measured with the FOPI detector at GSI-Darmstadt, are
investigated as a possible probe of isospin effects in high density nuclear
matter. The measured double ratio ()/() is
compared to the predictions of a thermal model and a Relativistic Mean Field
transport model using two different collision scenarios and under different
assumptions on the stiffness of the symmetry energy. We find a good agreement
with the thermal model prediction and the assumption of a soft symmetry energy
for infinite nuclear matter while more realistic transport simulations of the
collisions show a similar agreement with the data but also exhibit a reduced
sensitivity to the symmetry term.Comment: 5 pages, 3 figures. accepted for publication in Phys. Rev.
Two-proton small-angle correlations in central heavy-ion collisions: a beam-energy and system-size dependent study
Small-angle correlations of pairs of protons emitted in central collisions of
Ca + Ca, Ru + Ru and Au + Au at beam energies from 400 to 1500 MeV per nucleon
are investigated with the FOPI detector system at SIS/GSI Darmstadt.
Dependences on system size and beam energy are presented which extend the
experimental data basis of pp correlations in the SIS energy range
substantially. The size of the proton-emitting source is estimated by comparing
the experimental data with the output of a final-state interaction model which
utilizes either static Gaussian sources or the one-body phase-space
distribution of protons provided by the BUU transport approach. The trends in
the experimental data, i.e. system-size and beam energy dependences, are well
reproduced by this hybrid model. However, the pp correlation function is found
rather insensitive to the stiffness of the equation of state entering the
transport model calculations.Comment: 9 pages, 8 figures, accepted at Eur. Phys. Journ.
Searching Toward Pareto-Optimal Device-Aware Neural Architectures
Recent breakthroughs in Neural Architectural Search (NAS) have achieved
state-of-the-art performance in many tasks such as image classification and
language understanding. However, most existing works only optimize for model
accuracy and largely ignore other important factors imposed by the underlying
hardware and devices, such as latency and energy, when making inference. In
this paper, we first introduce the problem of NAS and provide a survey on
recent works. Then we deep dive into two recent advancements on extending NAS
into multiple-objective frameworks: MONAS and DPP-Net. Both MONAS and DPP-Net
are capable of optimizing accuracy and other objectives imposed by devices,
searching for neural architectures that can be best deployed on a wide spectrum
of devices: from embedded systems and mobile devices to workstations.
Experimental results are poised to show that architectures found by MONAS and
DPP-Net achieves Pareto optimality w.r.t the given objectives for various
devices.Comment: ICCAD'18 Invited Pape
Direct comparison of phase-space distributions of K- and K+ mesons in heavy-ion collisions at SIS energies - evidence for in-medium modifications of kaons ?
The ratio of K- to K+ meson yields has been measured in the systems RuRu at
1.69 A GeV, Ru+Zr at 1.69 A GeV, and Ni+Ni at 1.93 A GeV incident beam kinetic
energy. The yield ratio is observed to vary across the measured phase space.
Relativistic transport-model calculations indicate that the data are best
understood if in-medium modifications of the kaons are taken into account.Comment: 14 pages including 3 figure
Charged pion production in Ru+Ru collisions at 400A and 1528A MeV
We present transverse momentum and rapidity spectra of charged pions in
central Ru + Ru collisions at 400 and 1528 MeV. The data exhibit enhanced
production at low transverse momenta compared to the expectations from the
thermal model that includes the decay of -resonances and thermal
pions. Modification of the -spectral function and the Coulomb
interaction are necessary to describe the detailed shape of the transverse
momentum spectra. Within the framework of the thermal model, the freeze-out
radii of pions are similar at both beam energies. The IQMD model reproduces the
shapes of the transverse momentum and rapidity spectra of pions, but the
predicted absolute yields are larger than in the measurements, especially at
lower beam energy.Comment: 12 pages, 11 figure
Strange meson production in Al+Al collisions at 1.9A GeV
The production of K, K and (1020) mesons is studied in Al+Al
collisions at a beam energy of 1.9A GeV which is close or below the production
threshold in NN reactions. Inverse slopes, anisotropy parameters, and total
emission yields of K mesons are obtained. A comparison of the ratio of
kinetic energy distributions of K and K mesons to the HSD transport
model calculations suggests that the inclusion of the in-medium modifications
of kaon properties is necessary to reproduce the ratio. The inverse slope and
total yield of mesons are deduced. The contribution to K production
from meson decays is found to be [17 3 (stat) (syst)]
%. The results are in line with previous K and data obtained for
different colliding systems at similar incident beam energies.Comment: 16 pages, 11 figure
Measurement of and mesons in Al+Al collisions at 1.9 GeV
New measurement of sub-threshold and production is
presented. The experimental data complete the measurement of strange particles
produced in Al+Al collisions at 1.9 GeV measured with the FOPI detector at
SIS/GSI. The / yield ratio is found to be and is in good agreement with the
UrQMD model prediction. These measurements provide information on in-medium
cross section of - fusion which is the dominant process on
sub-threshold production.Comment: 5 pages, 4 figures, accepted for publication in Phys. Rev.
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