Hund's-Rule Coupling Effect in Itinerant Ferromagnetism

We present a general model which includes the ferromagnetic Kondo lattice and the Hubbard model as special cases. The stability of the ferromagnetic state is investigated variationally. We discuss the mechanism of ferromagnetism in metallic nickel, emphasizing the importance of orbital degeneracy and the effect of the Hund's-rule coupling.Comment: 19 pages, 10 figures, to appear in Prog.Theor.Phy

Magnetospheric electrostatic emissions and cold plasma densities

A synoptic study of electric wave, magnetometer, and plasma data from IMP-6 was carried out for times when banded electrostatic waves are observed between harmonics of the electron gyrofrequency in the earth's outer magnetosphere. Four separate classes of such waves were previously identified. The spatial and temporal occurrences of waves in each class are summarized here, as are correlations of occurrence with geomagnetic activity. Most importantly, associations between the observations of waves of different classes and the relative portions of cold and hot electrons present at the position of the spacecraft are established. Finally, evidence for the signature of the loss cone is sought in the plasma data

Comparative Evolution of Jupiter and Saturn

We present evolutionary sequences for Jupiter and Saturn, based on new nongray model atmospheres, which take into account the evolution of the solar luminosity and partitioning of dense components to deeper layers. The results are used to set limits on the extent to which possible interior phase separation of hydrogen and helium may have progressed in the two planets. When combined with static models constrained by the gravity field, our evolutionary calculations constrain the helium mass fraction in Jupiter to be between 0.20 and 0.27, relative to total hydrogen and helium. This is in agreement with the Galileo determination. The helium mass fraction in Saturn's atmosphere lies between 0.11 and 0.25, higher than the Voyager determination. Based on the discrepancy between the Galileo and Voyager results for Jupiter, and our models, we predict that Cassini measurements will yield a higher atmospheric helium mass fraction for Saturn relative to the Voyager value.Comment: 18 pages, LaTeX, 4 figures. submitted to ``Planetary and Space Science.'

Cumulant expansion of the periodic Anderson model in infinite dimension

The diagrammatic cumulant expansion for the periodic Anderson model with infinite Coulomb repulsion ($U=\infty$) is considered here for an hypercubic lattice of infinite dimension ($d=\infty$). The same type of simplifications obtained by Metzner for the cumulant expansion of the Hubbard model in the limit of $d=\infty$, are shown to be also valid for the periodic Anderson model.Comment: 13 pages, 7 figures.ps. To be published in J. Phys. A: Mathematical and General (1997

Scaling Relation for Excitation Energy Under Hyperbolic Deformation

We introduce a one-parameter deformation for one-dimensional (1D) quantum lattice models, the hyperbolic deformation, where the scale of the local energy is proportional to cosh lambda j at the j-th site. Corresponding to a 2D classical system, the deformation does not strongly modify the ground state. In this situation, the effective Hamiltonian of the quantum system shows that the quasi particle is weakly bounded around the center of the system. By analyzing this binding effect, we derive scaling relations for the mean-square width of confinement, the energy correction with respect to the excitation gap \Delta, and the deformation parameter $\lambda$. This finite-size scaling allows us to investigate excitation gap of 1D non-deformed bulk quantum systems.Comment: 9 pages, 5 figure

Using Raman Spectroscopy for Intraoperative Margin Analysis in Breast Conserving Surgery

Breast Conserving Surgery (BCS) in the treatment of breast cancer aims to provide optimal oncological results, with minimal tissue excision to optimise cosmetic outcome. Positive margins due to an inadequate resection occurs in 17% of UK patients undergoing BCS and prompts recommendation for further tissue re-excision to reduce recurrence risk. A second operation causes patient anxiety and significant healthcare costs. This issue could be resolved with accurate intra-operative margin analysis (IMA) to enable excision of all cancerous tissue at the index procedure. High wavenumber Raman Spectroscopy (HWN RS) is a vibrational spectroscopy highly sensitive to changes in protein/lipid environment and water content –biochemical differences found between tumour and normal breast tissue. We proposed that HWN RS could be used to differentiate between tumour and non-tumour breast tissue with a view to future IMA. This thesis presents the development of a Raman system to measure the HWN region capable of accurately detecting changes in protein, lipid and water content, in the presence of highly fluorescent surgical pigments such as blue dye that are present in surgically excised specimens. We investigate the relationship between changes in the HWN spectra with changes in water content in constructed breast phantoms to mimic protein and lipid rich environments and biological tissue. Human breast tissue of paired tumour and non-tumour samples were then measured and analysed. We found that breast tumour tissue is a protein rich, high water, low fat environment and that non-tumour is a low protein, fat rich environment with a low water content, and this can be used to identify breast cancer using HWN RS with excellent accuracy of over 90%. This thesis demonstrates a HWN RS Raman system capable of differentiating between tumour and non-tumour tissue in human breast tissue, and this has the potential to provide IMA in BCS

Discovering Constructivism: How A Project-Oriented Activity-Based Media Production Course Effectively Employed Constructivist Teaching Principles

The author uses his experience leading a project-oriented special-topics course as a case study in constructivist teaching methods. Citing relevant literature from the education field, this paper considers why students chosen to work for course credit on a promotional video for a university program considered the project their greatest academic learning experience. The author points out that communication media education has long championed activity and project-based learning and argues that educators could benefit from a deeper understanding of how and why such methods are effective

Insurgency in the Late Bronze Age Levant: A World-Systems Analysis of Three Egyptian Garrison Sites

The wide-ranging research focused on the turbulence of the Late Bronze Age in the Mediterranean and the Levant has not yet yielded a unified narrative of how this period was experienced across the region. While some sites exhibit no sign of the infamous collapse or ‘crisis,’ many others exhibit rapid abandonment or destruction layers. The narrative surrounding these destructions tends to be viewed as relating to foreign powers such as the imperial Egyptian invasion, Israel’s rising kingdom, or all manner of so-named ‘Sea Peoples.’ This macro-causal approach leaves fewer considerations of micro-scale incidents of local resistance/agency. Recent evidence from a New Kingdom outpost in Jaffa (Tel Yafo), excavated by the Jaffa Cultural Heritage Project (JCHP), sheds light on just such a possibility. Specifically, evidence suggests a local Canaanite resistance against Egyptian domination. In this thesis, I reconsider a number of Late Bronze Age, New Kingdom outposts to better gauge the intensity of Egyptian influence in the Levant and to posit the probability of local efforts to collectively resist

Low-energy excitations of the one-dimensional half-filled SU(4) Hubbard model with an attractive on-site interaction: Density-matrix renormalization-group calculations and perturbation theory

We investigate low-energy excitations of the one-dimensional half-filled SU(4) Hubbard model with an attractive on-site interaction U < 0 using the density matrix renormalization group method as well as a perturbation theory. We find that the ground state is a charge density wave state with a long range order. The ground state is completely incompressible since all the excitations are gapful. The charge gap which is the same as the four-particle excitation gap is a non-monotonic function of U, while the spin gap and others increase with increasing |U| and have linear asymptotic behaviors.Comment: 4 pages, 3 figures, submitte