A METAPOPULATION MODEL FOR FERAL HOGS IN GREAT SMOKY MOUNTAINS NATIONAL PARK

Feral Hogs (Sus scrofa) are an invasive species that have occupied the Great Smoky Mountains National Park since the early 1900s. Recent studies on vegetation, mast, and harvest history were important for our work. Using these data, a model with discrete time and space was formulated to represent the feral hog dynamics in the Park. Management strategies and key characteristics of the population were investigated. The model uses observed mast variation to help govern population dynamics and results indicate that Park control efforts have limited the growth of the population.     

The 4d auger,coster-kronig,and recombination spectra of the lanthanides

A complete set of electron-excited 4d-basedAuger spectra of the lanthanide metals from lanthanum to lutetium (except the unstable promethium) is presented, in both differential and integral forms. It is believed that the set is more representative of clean surfaces of the lanthanides than any published hitherto. With the help of binding energy and electron loss measurements made in this laboratory and elsewhere, values of the various possible Auger, Coster—Kronig, and direct recombination transition energies are calculated, and for each transition a “centre of gravity” is derived based on relative intensities of final state multiplets, electron occupation of core levels, etc. By using arguments based on trends in the spectra across the series, on theoretically and experimentally derived values of U_eff for the difference 4fⁿ⁺¹→4f^n?1, and on plausibility, values of U_eff for 4fⁿ→ 4f^n?2 as well as for the other final state hole pair configurations are allocated. The relaxed transition energies so calculated are then compared with the experimental energies, from which it is possible in most cases to make assignment of the spectral features to the various transitions. As a result it is found that there are some significant disagreements with the theoretical rates of McGuire for lanthanide free atoms. The reasons for these disagreements are discussed, and an empirical model based on effective 4f and 5d populations and on the restrictions imposed by spin alignment is used to resolve the differences qualitatively.     

Sorption of trace metals (Cu, Pb, Zn) by suspended lake particles in artificial (0.005 M NaNO3) and natural (Esthwaite Water) freshwaters

The sorption of Cu, Pb, and Zn onto natural lake particles, suspended in 0.005 M NaNO₃ solution and in a natural lake water (Esthwaite Water, Cumbria, UK), was studied as a function of pH and time in a series of laboratory experiments, under environmentally realistic conditions. The sorption of all three metals increased with increasing pH and reaction time (2 h and 7 days). In 0.005 M NaNO₃ solution, the well-defined sorption edges spanned 2–2.5 pH units for Cu and Pb, and ≈ 4 pH units for Zn. In the natural lake water, the Cu sorption edge was broader and both Cu and Zn were less strongly sorbed. The binding stability decreased in the order Pb>Cu>Zn. Competitive adsorption onto surface sites appeared to be the main factor determining the observed sorption behaviour. Application of a macroscopic metal exchange model to the 7 day NaNO₃ results enabled the surface site concentration to be estimated as 0.79 ± 0.07 mmol g⁻¹. The modelling exercise suggested that an observed shift in the sorption edge of Zn, in the presence of Pb and Cu, was due to competition for surface sites. The experimental data are in good general agreement with field observations of trace metal behaviour in Cumbrian lakes. The almost total sorption of Pb by lake particles throughout the in-situ pH range is compatible with previous field measurements including trace metal budgets and residence times. Dissolved Zn concentrations in the lake are lower than predicted by the sorption experiments, but the lower lake concentrations are consistent with the previously observed scavenging of Zn by planktonic algae. Both the decreased sorption of Cu in the experiments with natural lake water, compared to that in NaNO₃ solution, and the relatively small-scale removal of dissolved Cu by particles in the lake itself can partially be explained by humic complexation.     

模糊随机变量的大数定律

给出模糊随机变量的Chebyshev不等式,在此基础上证明模糊随机变量的Chebyshev大数定律,并将经典的XИHЧИH大数定律推广到模糊随机变量。     

Direct observation of Fermi—Dirac distribution of conduction electrons in ruthenium: a photoemission study

Photoemission spectra of Ru(001) have been measured at high resolution (16meV) over the temperature range 130K? T ? 770 K. It is found that the bandshape close to threshold corresponds closely to that calculated from the Fermi-Dirac distribution function at the appropriate temperature.