7,187 research outputs found
Evaluating the demand for aquaculture insurance: An investigation of fish farmers' willingness to pay in central coastal areas in China
Despite the remarkable development in its fishery sector, the penetration rate of fishery insurance in China is considerably low. This paper examines the key factors that contribute to the poor performance of fishery insurance, in particular aquaculture insurance, in China. The double-bounded dichotomous choice contingent valuation method (DB DCCVM) is used to investigate fish farmers’ willingness to pay (WTP) for an insurance program, based on a survey of 1280 fish farmers in three coastal cities in China. The results indicate that fish farmers’ decisions on adoption of an insurance scheme depend on various factors, among which magnitude of loss, fish farmers’ awareness toward insurance and their education all have a positive impact. However, income and farming years are more likely to have a negative effect. In addition, the mean WTP for aquaculture insurance is estimated to be CNY 579 (US$ 90.05) 2 per household, which is equivalent to 1.5% of fish farmers' mean annual income. These results provide several policy implications for not only the Chinese government but also researchers as well as insurance companies
Superconductivity in Ti-doped Iron-Arsenide Compound Sr4Cr0.8Ti1.2O6Fe2As2
Superconductivity was achieved in Ti-doped iron-arsenide compound
Sr4Cr0.8Ti1.2O6Fe2As2 (abbreviated as Cr-FeAs-42622). The x-ray diffraction
measurement shows that this material has a layered structure with the space
group of \emph{P4/nmm}, and with the lattice constants a = b = 3.9003 A and c =
15.8376 A. Clear diamagnetic signals in ac susceptibility data and
zero-resistance in resistivity data were detected at about 6 K, confirming the
occurrence of bulk superconductivity. Meanwhile we observed a superconducting
transition in the resistive data with the onset transition temperature at 29.2
K, which may be induced by the nonuniform distribution of the Cr/Ti content in
the FeAs-42622 phase, or due to some other minority phase.Comment: 3 pages, 3 figure
Pressure Effect on the superconducting properties of LaO_{1-x}F_{x}FeAs(x=0.11) superconductor
Diamagnetic susceptibility measurements under high hydrostatic pressure (up
to 1.03 GPa) were carried out on the newly discovered Fe-based superconductor
LaO_{1-x}F_{x}FeAs(x=0.11). The transition temperature T_c, defined as the
point at the maximum slope of superconducting transition, was enhanced almost
linearly by hydrostatic pressure, yielding a dT_c/dP of about 1.2 K/GPa.
Differential diamagnetic susceptibility curves indicate that the underlying
superconducting state is complicated. It is suggested that pressure plays an
important role on pushing low T_c superconducting phase toward the main
(optimal) superconducting phase.Comment: 7 pages, 4 figure
Data-Driven Dynamic Modeling of Coupled Thermal and Electric Outputs of Microturbines
Microturbines (MTs) are among the most successfully commercialized distributed energy resources, especially when they are used for combined heat and power generation. However, the interrelated thermal and electrical system dynamic behaviors have not been fully investigated. This is technically challenging due to the complex thermo-fluid-mechanical energy conversion processes, which introduce multiple time-scale dynamics and strong nonlinearity into the analysis. To tackle this problem, this paper proposes a simplified model which can predict the coupled thermal and electric output dynamics of MTs. Considering the time-scale difference of various dynamic processes occurring within MTs, the electromechanical subsystem is treated as a fast quasi-linear process, while the thermo-mechanical subsystem is treated as a slow process with high nonlinearity. A three-stage subspace identification method is utilized to capture the dominant dynamics and predict the electric power output. For the thermo-mechanical process, a radial basis function model trained by the particle swarm optimization method is employed to handle the strong nonlinear characteristics. Experimental tests on a Capstone C30 MT show that the proposed modeling method can well capture the system dynamics, and produce a good prediction of the coupled thermal and electric outputs in various operating modes
Advances in the functional study of glutamine synthetase in plant abiotic stress tolerance response
Plant glutamine synthetase (GS, EC6.3.1.2) catalyzes the synthesis of glutamine from glutamate and ammonium ions and acts as a key enzyme in the nitrogen metabolic pathway in organisms. Nitrogen is an essential element for plant growth and development and plays an important role in crop yield and quality formation. Therefore, GS is crucial in many physiological processes in plants. Currently, nitrogen regulation by GS in plants is well-studied in terms of its effect on plant growth and development. This article reviews the regulatory role of plant GS and its molecular mechanism in mitigating stress injury, such as low or high temperature, salinity, drought and oxidation. The function of plant GS in stress tolerance response is focused. The review aims to provide a reference for the utilization of plant GS in crop stress tolerance breeding
CP-violating asymmetry in in the Skyrme model
We study the CP-violating asymmetry in nonleptonic decay .
By employing the Skyrme model to calculate this decay amplitude contributed by
the gluonic diploe operator, we find a possible large CP-violating asymmetry
could be expected, which is consistent with the previous study.Comment: LaTeX file, To appear in J Phys G: Nucl Phys and Part Phy
Angular dependence of resistivity in the superconducting state of NdFeAsOF single crystals
We report the results of angle dependent resistivity of
NdFeAsOF single crystals in the superconducting state. By
doing the scaling of resistivity within the frame of the anisotropic
Ginzburg-Landau theory, it is found that the angle dependent resistivity
measured under different magnetic fields at a certain temperature can be
collapsed onto one curve. As a scaling parameter, the anisotropy can
be determined for different temperatures. It is found that
increases slowly with decreasing temperature, varying from 5.48
at T=50 K to 6.24 at T=44 K. This temperature dependence can be
understood within the picture of multi-band superconductivity.Comment: 7 pages, 4 figure
Optimal and Low Complexity Control of SOA-Based Optical Switching with Particle Swarm Optimisation
We propose a reliable, low-complexity particle swarm optimisation (PSO) approach to control semiconductor optical amplifier (SOA)-based s witches. We experimentally demonstrate less than 610 ps off-on switching (settling) time and less than 2.2% overshoot with 20x lower sampling rate and 8x reduced DAC resolution
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