4,841 research outputs found
Nuclear incompressibility using the density dependent M3Y effective interaction
A density dependent M3Y effective nucleon-nucleon (NN) interaction which was
based on the G-matrix elements of the Reid-Elliott NN potential has been used
to determine the incompressibity of infinite nuclear matter. The nuclear
interaction potential obtained by folding in the density distribution functions
of two interacting nuclei with this density dependent M3Y effective interaction
had been shown earlier to provide excellent descriptions for medium and high
energy and heavy ion elastic scatterings as well as and heavy
cluster radioactivities. The density dependent parameters have been chosen to
reproduce the saturation energy per nucleon and the saturation density of spin
and isospin symmetric cold infinite nuclear matter. The result of such
calculations for nuclear incompressibility using the density dependent M3Y
effective interaction based on the G-matrix elements of Reid-Elliott NN
potential predicts a value of about 300 MeV for nuclear incompressibility.Comment: 4 Page
Neutron transition strengths of states in the neutron rich Oxygen isotopes determined from inelastic proton scattering
A coupled-channel analysis of the O data has been
performed to determine the neutron transition strengths of 2 states in
Oxygen targets, using the microscopic optical potential and inelastic form
factor calculated in the folding model. A complex density- and \emph{isospin}
dependent version of the CDM3Y6 interaction was constructed, based on the
Brueckner-Hatree-Fock calculation of nuclear matter, for the folding model
input. Given an accurate isovector density dependence of the CDM3Y6
interaction, the isoscalar () and isovector () deformation
lengths of 2 states in O have been extracted from the
folding model analysis of the data. A specific -dependence of
and has been established which can be linked to the
neutron shell closure occurring at approaching 16. The strongest isovector
deformation was found for 2 state in O, with about 2.5
times larger than , which indicates a strong core polarization by the
valence neutrons in O. The ratios of the neutron/proton transition
matrix elements () determined for 2 states in O have
been compared to those deduced from the mirror symmetry, using the measured
values of 2 states in the proton rich Ne and Mg
nuclei, to discuss the isospin impurity in the excitation of the
and isobars.Comment: Version accepted for publication in Physical Review
Pair formation and collapse in imbalanced Fermion populations with unequal masses
We present an exact Quantum Monte Carlo study of the effect of unequal masses
on pair formation in Fermionic systems with population imbalance loaded into
optical lattices. We have considered three forms of the attractive interaction
and find in all cases that the system is unstable and collapses as the mass
difference increases and that the ground state becomes an inhomogeneous
collapsed state. We also address the question of canonical vs grand canonical
ensemble and its role, if any, in stabilizing certain phases
Efficiency assessment of trypanocidal treatments in the research station of Avetonou in Togo
In Togo as elsewhere, among the animal trypanosomosis control strategies, the chemotherapy constitutes the most used method. In order to assess the efficiency of two trypanocidal drugs (isometamidium chloride and diminazene) on cattle, a longitudinal study was conducted from September to November 2011 in the research station of Avetonou located in the Prefecture of Agou in Togo. A parasitological survey was carried out on two groups of 90 cattle each (for a total of 180 cattle) using the buffy coat technique at regular intervals of two weeks over a total period of 56 days. The animals of the first group were treated with isometamidium chloride (0.5 mg/kg) and the second group (untreated animals) was used as a control group. The comparison of the incidence of trypanosomosis between the two groups was performed using three statistical tests: the Chisquared test, the test of risk Reduction, and the “Eisler ratio test”. These analyses revealed an inefficiency of the preventive treatment with isometamidium chloride at the dose of 0.5 mg/kg bodyweight contrarily to the curative treatment that was effective. For diminazene, used at a dose of 3.5 mg/kg bodyweight, strains of Trypanosoma vivax and Trypanosoma congolense were not eliminated in 14.29% of cases.Keyswords: Trypanocidal treatment, isometamidium, diminazene, Avétonou, Togo
Semi-supervised Convolutional Neural Networks for Flood Mapping using Multi-modal Remote Sensing Data
When floods hit populated areas, quick detection of flooded areas is crucial for initial response by local government, residents, and volunteers. Space-borne polarimetric synthetic aperture radar (PolSAR) is an authoritative data sources for flood mapping since it can be acquired immediately after a disaster even at night time or cloudy weather. Conventionally, a lot of domain-specific heuristic knowledge has been applied for PolSAR flood mapping, but their performance still suffers from confusing pixels caused by irregular reflections of radar waves. Optical images are another data source that can be used to detect flooded areas due to their high spectral correlation with the open water surface. However, they are often affected by day, night, or severe weather conditions (i.e., cloud). This paper presents a convolution neural network (CNN) based multimodal approach utilizing the advantages of both PolSAR and optical images for flood mapping. First, reference training data is retrieved from optical images by manual annotation. Since clouds may appear in the optical image, only areas with a clear view of flooded or non-flooded are annotated. Then, a semisupervised polarimetric-features-aided CNN is utilized for flood mapping using PolSAR data. The proposed model not only can handle the issue of learning with incomplete ground truth but also can leverage a large portion of unlabelled pixels for learning. Moreover, our model takes the advantages of expert knowledge on scattering interpretation to incorporate polarimetric-features as the input. Experiments results are given for the flood event that occurred in Sendai, Japan, on 12th March 2011. The experiments show that our framework can map flooded area with high accuracy (F1 = 96:12) and outperform conventional flood mapping methods
Optothermotronic effect as an ultrasensitive thermal sensing technology for solid-state electronics
The thermal excitation, regulation, and detection of charge carriers in solid-state electronics have attracted great attention toward high-performance sensing applications but still face major challenges. Manipulating thermal excitation and transport of charge carriers in nanoheterostructures, we report a giant temperature sensing effect in semiconductor nanofilms via optoelectronic coupling, termed optothermotronics. A gradient of charge carriers in the nanofilms under nonuniform light illumination is coupled with an electric tuning current to enhance the performance of the thermal sensing effect. As a proof of concept, we used silicon carbide (SiC) nanofilms that form nanoheterostructures on silicon (Si). The sensing performance based on the thermal excitation of charge carriers in SiC is enhanced by at least 100 times through photon excitation, with a giant temperature coefficient of resistance (TCR) of up to −50%/K. Our findings could be used to substantially enhance the thermal sensing performance of solid-state electronics beyond the present sensing technologies
Studies of chain substitution caused sub-fibril level differences in stiffness and ultrastructure of wildtype and oim/oim collagen fibers using multifrequency-AFM and molecular modeling.
Molecular alteration in type I collagen, i.e., substituting the α2 chain with α1 chain in tropocollagen molecule, can cause osteogenesis imperfecta (OI), a brittle bone disease, which can be represented by a mouse model (oim/oim). In this work, we use dual-frequency Atomic Force Microscopy (AFM) and incorporated with molecular modeling to quantify the ultrastructure and stiffness of the individual native collagen fibers from wildtype (+/+) and oim/oim diseased mice humeri. Our work presents direct experimental evidences that the +/+ fibers have highly organized and compact ultrastructure and corresponding ordered stiffness distribution. In contrast, oim/oim fibers have ordered but loosely packed ultrastructure with uncorrelated stiffness distribution, as well as local defects. The molecular model also demonstrates the structural and molecular packing differences between +/+ and oim/oim collagens. The molecular mutation significantly altered sub-fibril structure and mechanical property of collagen fibers. This study can give the new insight for the mechanisms and treatment of the brittle bone disease
Alpha-nucleus potential for alpha-decay and sub-barrier fusion
The set of parameters for alpha-nucleus potential is derived by using the
data for both the alpha-decay half-lives and the fusion cross-sections around
the barrier for reactions alpha+40Ca, alpha+59Co, alpha+208Pb. The alpha-decay
half-lives are obtained in the framework of a cluster model using the WKB
approximation. The evaluated alpha-decay half-lives and the fusion
cross-sections agreed well with the data. Fusion reactions between
alpha-particle and heavy nuclei can be used for both the formation of very
heavy nuclei and spectroscopic studies of the formed compound nuclei.Comment: 10 pages, 5 figure
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