镇海棘螈繁殖群体生态和遗传结构研究

genetics, such as: population size, reproduction, mating system, growth, development,genetic structure and systematics status; The main results are presented below: The seasonal variation of the operational sexual ratio of this animal was found in the field and the ration always bias the female in the breeding season. Aiming at this character and considering the distance of time and space of both sexual habitat in breeding season, we census female population first by toe-clipping mark-recapture method, then estimated the population size with the definitive sexual ratio. Up to now, this species was found only at the Beilun district of the Ningbo City. The population size of the Ruiyan Temple Forest Park approximates to 369. The status of this population is extremely endangered, so besides protecting this population at the original locality, we also suggested to breed the salamander in fenced locality and to hatch embryos artificially, and send metamorphosed juveniles back to nature. We can transfer some individuals to other similar habitats or breed them under artificial conditions for saving this species from extinction. The early developmental stage of the Chinhai salamander is the same as its relative species, E. andersoni. Their balanceres are poorly developed and disappear very early. Temperature and moisture significantly influence the embryonic development of the Chinhai salamander. The embryonic stage is approx. 29 days under room temperature. The hatchling grows in a logarithmic curve. The larvae stage in water is approx. 58- 88 days. Many factors influence the nomal development, including two aspects of internal and external. Due to these factors, the effective protected measures were presented in detail. The breeding migration of E. chinhaiensis takes place at late March～late April every year. This salamander's hatching rate is high, but the rate of hatchling migrating into water is low. The average effectiveness of all the nest sites is 36.7%. The maternal self-conservation was contrary to the reproductive success of the egg-laying strategy. In the strategy of egg-laying behavior, the first factor selected by the female was its self-conservation, the second is embryonic survival rate, and the last is rate of hatchling survival rate. The oviposition selection is significant for the survival of the larvae. Based on the analysis of the evolutionary process of reproductive behaviors nad egg-laying site selections of all genera of the family Salamandridae, we deduced that perhaps Echinotriton is a transitional type in the evolutionary process from water to land. Due to its location in the adaptive stage in the terrestrial evolution, Echinotriton chinhaiensis's terrestrial nest may be one of important reason that causes this species to be endangered. The genetic deversity analysis shows that although the population size of the Chinhai salamander is quite small compared to other Chinese salamandrid species, the genetic diversity of this population is not reduce remarkably. We explain this phenomena with the polygamy mating system of this species. The result of 4 families' parenthood determinations shows that the parenhood determination can be taken without any paternal information. The "children" of every female include rich genetic information from at least two "fathers". It implies that female Chinhai salamander mates more than once with different males in a breeding season. The molecular evidence, the behavioral observation evidences and the sperm evidence in the female cloaca proved that this species has a polygamy mating system. The kin recognition in the mating of adult salamander was first discussed. The taxonomic status and phylogenetic relationships of 12 species representing 6 genera in the family Salamandridae were studied using DNA fingerprinting. The results showed that the DNA fingerprinting. The results showed that the DNA fingerprinting patterns demonstrated rich genetic diversity and species diversity, and also revealed the taxonomic status and phylogenetic relationshipes of higher taxa to a certain extent. The results are highly consistent with those obtained from the studies based on the morphology, ecology, cytology and molecular biology. The compreshensive analysis indicate that Tylototrition hainanensis and T. wenxianensis should be valid species; Echinotriton should be a valid genus;Tylotortriton is a natural cluster; Tylotortriton asperrimus should be put in Tylototrition rather than in Echinotriton, Hypselotriton and Allomestriton are synonyms of Cynops and Paramesotriton, respectively. There are three main groups in Chinese salamandride: Cynops, Paramesotriton and Pachytrition from the first group, the species of the Tylototriton from the second, and E. chinhaiensis composes the third.

Behavior of crystalline silicon under huge electronic excitations: A transient thermal spike description

Recent experimental works devoted to the phenomena of mixing observed at metallic multilayers Ni/Si irradiated by swift heavy ions irradiations make it necessary to revisit the insensibility of crystalline Si under huge electronic excitations. Knowing that Ni is an insensitive material, such observed mixing would exist only if Si is a sensitive material. In order to extend the study of swift heavy ion effects to semiconductor materials, the experimental results obtained in bulk silicon have been analyzed within the framework of the inelastic thermal spike model. Provided the quenching of a boiling ( or vapor) phase is taken as the criterion of amorphization, the calculations with an electron-phonon coupling constant g(300 K) = 1.8 x 10(12) W/cm(3)/K and an electronic diffusivity D-e(300 K) = 80 cm(2)/s nicely reproduce the size of observed amorphous tracks as well as the electronic energy loss threshold value for their creation, assuming that they result from the quenching of the appearance of a boiling phase along the ion path. Using these parameters for Si in the case of a Ni/Si multilayer, the mixing observed experimentally can be well simulated by the inelastic thermal spike model extended to multilayers, assuming that this occurs in the molten phase created at the Ni interface by energy transfer from Si. (C) 2009 Elsevier B. V. All rights reserved.

Probing the high density behavior of the symmetry energy by using the free neutron-proton ratio

Based on the isospin- and momentum-dependent transport model IBUU04, the transverse momentum distributions of the free neutron-proton ratio in the Sn-132+(124) Sn reaction system at mid-central collisions with beam energies of 400/A MeV, 600/A MeV and 800/A MeV are studied by using two different symmetry energies. It is found that the free neutron-proton ratio as a function of the transverse momentum at the mid-rapidity is very sensitive to the density dependency of the symmetry energy especially at incident energies around 400/AMeV.

Probing the high density behavior of the symmetry energy by using proton elliptic flow

Based on the isospin- and momentum-dependent transport model IBUU04, we calculated the reaction of the Sn-132+Sn-124 systems in semi-central collisions at beam energies of 400/A MeV, 600/A MeV and 800/A MeV by adopting two different density dependent symmetry energies. It was found that the proton differential elliptic flow as a function of transverse momentum is quite sensitive to the density dependence of symmetry energy, especially for the considered beam energy range. Therefore the proton differential elliptic flow may be considered as a robust probe for investigating the high density behavior of symmetry energy in intermediate energy heavy ion collisions.

The neutron/proton ratio of squeezed-out nucleons and the high density behavior of the nuclear symmetry energy

Within a transport model it is shown that the neutron/proton ratio of squeezed-out nucleons perpendicular to the reaction plane, especially at high transverse momenta, in heavy-ion reactions induced by high energy neutron-rich nuclei can be a useful tool for studying the high density behavior of the nuclear symmetry energy.

Double neutron-proton differential transverse flow as a probe for the high density behavior of the nuclear symmetry energy

The double neutron-proton differential transverse flow taken from two reaction systems using different isotopes of the same element is studied at incident beam energies of 400 and 800 MeV/nucleon within the framework of an isospin- and momentum-dependent hadronic transport model IBUU04. The double differential flow is found to retain about the same sensitivity to the density dependence of the nuclear symmetry energy as the single differential flow in the more neutron-rich reaction. Because the double differential flow reduces significantly both the systematic errors and the influence of the Coulomb force, it is thus more effective probe for the high-density behavior of the nuclear symmetry energy.

Probing the high density behavior of the symmetry energy by using the neutron-proton differential flow

Based on the isospin- and momentum-dependent transport model IBUU04, we investigated the neutron-proton differential flow in the (132) Sn + (124) Sn mid-central collisions at beam energies of 400MeV/A, 600MeV/A and 800MeV/A by adopting two different symmetry energies. It was found that the neutron-proton differential flow as a function of rapidity is very sensitive to the density dependence of symmetry energy, especially at incident energies around 400MeV/A

Exotic behavior of elastic scattering differential cross-sections of weakly bound nucleus F-17 at small angles

The differential cross-sections for elastic scattering of F-17 and O-17 on Pb-208 have been measured at Radioactive Ion Beam Line at Lanzhou (RIBLL). The variation of the logarithms of differential cross-sections with the square of scattering angles shows clearly that there exists a turning point in the range of small scattering angles (6 degrees-20 degrees) for F-17 having exotic structure, while no turning point was observed in the O-17 elastic scattering. The experimental results have been compared with previous data. Systematical analysis on the available data seems to conclude that there is an exotic behavior of elastic scattering differential cross-sections of weakly bound nuclei with halo or skin structure as compared with that of the ordinary nuclei near stable line. Therefore the fact that the turning point of the logarithms of differential cross-sections appears at small angle for weakly bound nuclei could be used as a new probe to investigate the halo and skin phenomenon.

Single and double pi(-)/pi(+) ratios in heavy-ion reactions as probes of the high-density behavior of the nuclear symmetry energy

Based on the isospin- and momentum-dependent hadronic transport model IBUU04, effects of the nuclear symmetry energy on the single and double pi(-)/pi(+) ratios in central reactions of Sn-132+Sn-124 and Sn-112+Sn-112 at a beam energy of 400 MeV/nucleon are studied. It is found that around the Coulomb peak of the single pi(-)/pi(+) ratio the double pi(-)/pi(+) ratio taken from the two isotopic reactions retains about the same sensitivity to the density dependence of nuclear symmetry energy. Because the double pi(-)/pi(+) ratio can significantly reduce the systematic errors, it is thus a more effective probe for the high-density behavior of the nuclear symmetry energy.

Critical behavior of multifragmentation in finite nuclei and extraction of critical exponents

Using a phenomenological asymmetric nuclear equation of state, we obtained pressure-density isotherms of the finite nucleus Sn-112 simulated in r-space and in p-space and constructed the nuclear fragments by using the coalescence model. After correlatively analysing the fragments, the signal of critical behavior has been found and critical exponents were also extracted.

The annealing behavior of Cu nanoparticles in Ar-ion implanted spinel

Magnesium aluminate spinel crystals (MgAl2O4 (1 1 0)) deposited with 30 nm Cu film on surface were implanted with 110 key Ar-ions to a fluence of 1.0 x 10(17) ions/cm(2) at 350 degrees C, and then annealed in vacuum condition at the temperature of 500, 600, 700, 800 and 900 degrees C for 1 h, respectively. Ultraviolet-visible spectrometry (UV-VIS), scanning electron microscopy (SEM), Rutherford backscattering (RBS) and transmission electron microscopy (TEM) were adopted to analyze the specimens. After implantation, the appearance of surface plasmon resonance (SPR) absorbance peak in the UV-VIS spectrum indicated the formation of Cu nanoparticles, and the TEM results for 500 degrees C also confirmed the formation of Cu nanoparticles at near-surface region. In annealing process, The SPR absorbance intensity increased at 500 and 700 degrees C, decreased with a blue shift of the peak position at 600 and 800 degrees C, and the peak disappeared at 900 degrees C. The SPR absorbance intensity evolution with temperature was discussed combined with other measurement results (RBS, SEM and TEM). (C) 2010 Elsevier B.V. All rights reserved.

System size and beam energy effects on probing the high-density behavior of nuclear symmetry energy with pion ratio

Based on the isospin-and momentum-dependent hadronic transport model IBUU04, we have investigated the pi(-)/pi(+) ratio in the following three reactions: Ca-48+Ca-48, Sn-124 +Sn-124 and Au-197+Au-197 with nearly the same isospin asymmetry but different masses, at the bombarding energies from 0.25 to 0.6 A GeV. It is shown that the sensitivity of probing the E-sym (rho) with pi(-)/pi(+) increases with increasing the system size or decreasing the beam energy, showing a correlation to the degree of isospin fractionation. Therefore, with a given isospin asymmetry, heavier system at energies near the pion threshold is preferential to study the behavior Of nuclear symmetry energy at supra-saturation densities.

Probing high-density behavior of symmetry energy from pion emission in heavy-ion collisions

Within the framework of the improved isospin dependent quantum molecular dynamics (ImIQMD) model, the emission of pion in heavy-ion collisions in the region 1 A GeV as a probe of nuclear symmetry energy at supra-saturation densities is investigated systematically, in which the pion is considered to be mainly produced by the decay of resonances Delta(1232) and N*(1440). The total pion multiplicities and the pi(-)/pi(+) yields are calculated for selected Skyrme parameters SkP, SLy6. Ska and SIB, and also for the cases of different stiffness of symmetry energy with the parameter SLy6. Preliminary results compared with the measured data by the FOPI Collaboration favor a hard symmetry energy of the potential term proportional to (rho/rho(0))(gamma s) with gamma(s) = 2. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.

Power law behavior of the isotope yield distributions in the multifragmentation regime of heavy ion reactions

Isotope yield distributions in the multifragmentation regime were studied with high-quality isotope identification, focusing on the intermediate mass fragments (IMFs) produced in semiviolent collisions. The yields were analyzed within the framework of a modified Fisher model. Using the ratio of the mass-dependent symmetry energy coefficient relative to the temperature, a(sym)/T, extracted in previous work and that of the pairing term, a(p)/T, extracted from this work, and assuming that both reflect secondary decay processes, the experimentally observed isotope yields were corrected for these effects. For a given I = N - Z value, the corrected yields of isotopes relative to the yield of C-12 show a power law distribution Y (N, Z)/Y(C-12) similar to A(-tau) in the mass range 1 <= A <= 30, and the distributions are almost identical for the different reactions studied. The observed power law distributions change systematically when I of the isotopes changes and the extracted tau value decreases from 3.9 to 1.0 as I increases from -1 to 3. These observations are well reproduced by a simple deexcitation model, with which the power law distribution of the primary isotopes is determined to be tau(prim) = 2.4 +/- 0.2, suggesting that the disassembling system at the time of the fragment formation is indeed at, or very near, the critical point.