27,110 research outputs found
Stocking, Enhancement, and Mariculture of Penaeus orientalis and Other Species in Shanghai and Zhejiang Provinces, China
China's marine aquaculture landings provide only 18% of its combined freshwater and amrine capture and culture landings, at a per-capita consumption of only 3.2 kg/yr out of a total of 18.1 kg/yr. We described development and some of the results of long-term mariculture and stocking/enhancement projects that have been underway for up to 20 years in the Hangzhou Bay area. Penaeus orientalis (also referred to as P. chinensis) stocking provided up to 400 t/yr, at a total cost-benefit ratio of up to 8 Yuan of landed shrimp per Yuan invested in shrimp stocking. Over 40 t of Penaeus orientalis were produced commercially in 1993, with proceeds being used to fund mariculture and fisheries research. Large scale edible jellyfish restocking is also underway, while semicommercial culture of abalone, Haliotis diversicolor, has been successful. Technical problems limitig mariculture have been solved successfully for some species
Multivariate adaptive regression splines for estimating riverine constituent concentrations
Regression-based methods are commonly used for riverine constituent concentration/flux estimation, which is essential for guiding water quality protection practices and environmental decision making. This paper developed a multivariate adaptive regression splines model for estimating riverine constituent concentrations (MARS-EC). The process, interpretability and flexibility of the MARS-EC modelling approach, was demonstrated for total nitrogen in the Patuxent River, a major river input to Chesapeake Bay. Model accuracy and uncertainty of the MARS-EC approach was further analysed using nitrate plus nitrite datasets from eight tributary rivers to Chesapeake Bay. Results showed that the MARS-EC approach integrated the advantages of both parametric and nonparametric regression methods, and model accuracy was demonstrated to be superior to the traditionally used ESTIMATOR model. MARS-EC is flexible and allows consideration of auxiliary variables; the variables and interactions can be selected automatically. MARS-EC does not constrain concentration-predictor curves to be constant but rather is able to identify shifts in these curves from mathematical expressions and visual graphics. The MARS-EC approach provides an effective and complementary tool along with existing approaches for estimating riverine constituent concentrations
The Physical Connections Among IR QSOs, PG QSOs and Narrow-Line Seyfert 1 Galaxies
We study the properties of infrared-selected QSOs (IR QSOs),
optically-selected QSOs (PG QSOs) and Narrow Line Seyfert 1 galaxies (NLS1s).
We compare their properties from the infrared to the optical and examine
various correlations among the black hole mass, accretion rate, star formation
rate and optical and infrared luminosities. We find that the infrared excess in
IR QSOs is mostly in the far infrared, and their infrared spectral indices
suggest that the excess emission is from low temperature dust heated by
starbursts rather than AGNs. The infrared excess is therefore a useful
criterion to separate the relative contributions of starbursts and AGNs. We
further find a tight correlation between the star formation rate and the
accretion rate of central AGNs for IR QSOs. The ratio of the star formation
rate and the accretion rate is about several hundred for IR QSOs, but decreases
with the central black hole mass. This shows that the tight correlation between
the stellar mass and the central black hole mass is preserved in massive
starbursts during violent mergers. We suggest that the higher Eddington ratios
of NLS1s and IR QSOs imply that they are in the early stage of evolution toward
classical Seyfert 1's and QSOs, respectively.Comment: 32 pages, 6 figures, accepted by Ap
Equation of motion for multiqubit entanglement in multiple independent noisy channels
We investigate the possibility and conditions to factorize the entanglement
evolution of a multiqubit system passing through multi-sided noisy channels. By
means of a lower bound of concurrence (LBC) as entanglement measure, we derive
an explicit formula of LBC evolution of the N-qubit generalized
Greenberger-Horne-Zeilinger (GGHZ) state under some typical noisy channels,
based on which two kinds of factorizing conditions for the LBC evolution are
presented. In this case, the time-dependent LBC can be determined by a product
of initial LBC of the system and the LBC evolution of a maximally entangled
GGHZ state under the same multi-sided noisy channels. We analyze the realistic
situations where these two kinds of factorizing conditions can be satisfied. In
addition, we also discuss the dependence of entanglement robustness on the
number of the qubits and that of the noisy channels.Comment: 14 page
Isospin effect on nuclear stopping in intermediate energy Heavy Ion Collisions
By using the Isospin Dependent Quantum Molecular Dynamics Model (IQMD), we
study the dependence of nuclear stopping Q_{ZZ}/A and R in intermediate energy
heavy ion collisions on system size, initial N/Z, isospin symmetry potential
and the medium correction of two-body cross sections. We find the effect of
initial N/Z ratio, isospin symmetry potential on stopping is weak. The
excitation function of Q_{ZZ}/A and R depends on the form of medium correction
of two-body cross sections, the equation of state of nuclear matter (EOS). Our
results show the behavior of the excitation function of Q_{ZZ}/A and R can
provide clearer information of the isospin dependence of the medium correction
of two-body cross sections.Comment: 3 pages including 4 figure
Hybrid exciton-polaritons in a bad microcavity containing the organic and inorganic quantum wells
We study the hybrid exciton-polaritons in a bad microcavity containing the
organic and inorganic quantum wells. The corresponding polariton states are
given. The analytical solution and the numerical result of the stationary
spectrum for the cavity field are finishedComment: 3 pages, 1 figure. appear in Communications in Theoretical Physic
Spectroscopic Properties of QSOs Selected from Ultraluminous Infrared Galaxy Samples
We performed spectroscopic observations for a large infrared QSO sample with
a total of 25 objects. The sample was compiled from the QDOT redshift survey,
the 1 Jy ULIRGs survey and a sample obtained by a cross-correlation study of
the IRAS Point Source Catalogue with the ROSAT All Sky Survey Catalogue.
Statistical analyses of the optical spectra show that the vast majority of
infrared QSOs have narrow permitted emission lines (with FWHM of Hbeta less
than 4000 km/s) and more than 60% of them are luminous narrow line Seyfert 1
galaxies. Two of the infrared QSOs are also classified as low ionization BAL
QSOs. More than 70% of infrared QSOs are moderately or extremely strong Fe II
emitters. This is the highest percentage of strong Fe II emitters in all
subclasses of QSO/Seyfert 1 samples. We found that the Fe II to Hbeta, line
ratio is significantly correlated with the [OIII]5007 peak and Hbeta blueshift.
Soft X-ray weak infrared QSOs tend to have large blueshifts in permitted
emission lines and significant Fe II48,49 (5100--5400 A) residuals relative to
the Boroson & Green Fe II template. If the blueshifts in permitted lines are
caused by outflows, then they appear to be common in infrared QSOs. As the
infrared-selected QSO sample includes both luminous narrow line Seyfert 1
galaxies and low ionization BAL QSOs, it could be a useful laboratory to
investigate the evolutionary connection among these objects.Comment: 35 pages,14 figures, 4 tables, accepted for publication in A
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