AN INDIVIDUAL‐BASED MODEL FOR FERAL HOGS IN GREAT SMOKY MOUNTAINS NATIONAL PARK

The expansion of feral hog (Sus scrofa) populations in the United States has resulted in increased efforts to develop and implement control strategies designed to minimize the impacts done by this invasive species. We describe an individual‐based model for feral hogs in Great Smoky Mountains National Park (GSMNP). The objectives of the model are to provide an understanding of the population dynamics of this feral hog population and to determine the efficacy of the annual harvest as a population control method. Results suggest that the dynamics of the population are driven by fall hard mast production and the GSMNP harvests currently limit growth of the population, but these control efforts have not reduced the population.     

The thymine radicals and their respective anions: molecular structures and electron affinities

The adiabatic electron affinities (AEA), vertical electron affinities (VEA) and vertical detachment energies (VDE) are predicted for six different radicals derived from thymine by the removal of one hydrogen atom. Geometry optimizations were carried out utilizing the DFT functionals B3LYP, BLYP and BP86 with double-c quality basis sets plus polarization and diffuse functions (DZP++). These methods have been carefully calibrated for the prediction of electron affinities [RIENSTRA-KIRACOFE, J. C., TSCHUMPER, G. S., SCHAEFER, H. F., NANDI, S., and ELLISON, G. B., 2002, Chem. Rev., 102, 231]. All optimized structures were confirmed to be minima via vibrational frequency analyses. Both the neutrals and the anion radicals were observed to possess C_s, symmetry, conserving the parent molecule's qualitative conformation. The electron affinities ranged between 1.04 and 3.74eV for the different radicals, contrasting to the small electron affinities associated with the closed-shell thymine species. The radicals with a hydrogen atom removed from one of the nitrogens present the largest electron affinities of all six radicals investigated (3.22eV for NI and 3.74eV for N3).     

Report On ‘Planning And Implementing Curriculum Change in Chemistry: A Case Study in Creating a Blended General/Organic Course Sequence’

A new curriculum involving a blended general and organic chemistry course is being introduced at San Jose State University this fall by Stephen Branz and Maureen Scharberg. They shared their experiences in creating this new curriculum and described how they overcame resistance to this change from the university community to the workshop participants. The participants of the workshop then had the opportunity to examine the new curriculum and consider how they would approach problems in both the planning and implementation phase of such a project. The workshop participants created a final list of ‘pros and cons’ for the planning stage (content, pedagogy, and transportability) and a list of possible strategies for the implementation stage (marketing, resources, and logistics).     

Rotational statistics and thermodynamic functions of hydrogen peroxide

Partition functions for both the rotational modes (hindered internal rotation and overall rotation) of the hydrogen peroxide (H₂O₂) molecule in the ground electronic state are studied using quantum and classical Gibbsian statistical mechanics. The partition functions are used to calculate rotational thermodynamic functions (internal energy, enthalpy, Helmholtz free energy, Gibbs free energy and entropy) of a hydrogen peroxide gas of weakly interacting molecules at temperatures above 300 K.     

Laser-induced condensation in colloid—polymer mixtures

We study a mixture of hard sphere colloidal particles and non-adsorbing polymers exposed to a plane wave external potential which represents a three-dimensional standing laser field. With computer simulations and density functional theory we investigate the structure and phase behaviour using the simple Asakura-Oosawa model. For varying laser wavelength λ we monitor the emergence of structure in response to the external field, as measured by the amplitude of the oscillations in the one-body density distribution. Between the ideal gas limit for small λ and the bulk limit of large λ there is a non-monotonic crossover that is governed by commensurability of λ and the colloid diameter. The theoretical curves are in good agreement with simulation results. Furthermore, the effect of the periodic field on the liquid-vapour transition is studied, a situation that we refer to as laser-induced condensation. Above a threshold value for λ the theoretical phase diagram indicates the stability of a ‘stacked’ fluid phase, which is a periodic succession (in the beam direction) of liquid and vapour slabs. This partially condensed phase causes a splitting of the liquid-vapour binodal leading to two critical and a triple point. All our predictions should be experimentally observable for colloid-polymer mixtures in an optical resonator.     

A Fast,Matrix-free Implicit Method for Computing Low Mach Number Flows on Unstructured Grids

A fast, matrix-free implicit method has been developed to solve low Mach number flow problems on unstructured grids. The preconditioned compressible Euler and Navier-Stokes equations are integrated in time using a linearized implicit scheme. A newly developed fast, matrix-free implicit method, GMRES + LU?SGS, is then applied to solve the resultant system of linear equations. A variety of computations has been made for a wide range of flow conditions, for both in viscid and viscous flows, in both 2D and 3D to validate the developed method and to evaluate the effectiveness of the GMRES + LU?SGS method. The numerical results obtained indicate that the use of the GMRES + LU?SGS method leads to a significant increase in performance over the LU?SGS method, while maintaining memory requirements similar to its explicit counterpart. An overall speedup factor from one to more than two order of magnitude for all test cases in comparison with the explicit method is demonstrated.     

Calculation of excitation functions of the 5 4 , 5 6 , 5 7 , 5 8 Fe(p,n) reaction from threshold to 30 MeV

The cross-sections for the formation of ^54,56,57,58Co in the ^54,56,57,58Fe(p, n) reaction from threshold to 30 MeV protons have been theoretically calculated using the TALYS-1.4 nuclear model code, whereby we have studied major nuclear reaction mechanisms, including direct, pre-equilibrium and compound nuclear reaction. Subsequently, the level density and shell damping parameters have been adjusted and at the same time, the odd–even effects are well comprehended. The excitation functions have been compared with experimental nuclear data. It is observed that the theoretical cross-sections match fairly well. Proton-induced reaction cross-sections provide clues to understand the nuclear structure and offers a good testing ground for ideas about nuclear forces. In addition, complete information in this field is very much required for application in accelerator-driven subcritical system.     

The Determination of Rate Constants from Known Linear Combinations of Concentrations in a Chemical Reaction

The determination of rate constants from known linear combinationsof concentrations in a chemical reaction is studied. Continuousdependence of the rate constants upon the data is demonstrated.A nonlinear least-squares method of approximation of the rateconstants is formulated and utilized in some numerical studies.