Spin(7)-manifolds with three-torus symmetry

Metrics of exceptional holonomy are vacuum solutions to the Einstein equation. In this paper we describe manifolds with holonomy contained in Spin(7) preserved by a three-torus symmetry in terms of tri-symplectic geometry of four-manifolds. These complement examples that have appeared in the context of domain wall problems in supergravity

Homogeneous spaces, multi-moment maps and (2,3)-trivial algebras

For geometries with a closed three-form we briefly overview the notion of multi-moment maps. We then give concrete examples of multi-moment maps for homogeneous hypercomplex and nearly Kaehler manifolds. A special role in the theory is played by Lie algebras with second and third Betti numbers equal to zero. These we call (2,3)-trivial. We provide a number of examples of such algebras including a complete list in dimensions up to and including five

Half-flat structures on S^3xS^3

We describe left-invariant half-flat SU(3)-structures on S^3xS^3 using the representation theory of SO(4) and matrix algebra. This leads to a systematic study of the associated cohomogeneity one Ricci-flat metrics with holonomy G_2 obtained on 7-manifolds with equidistant S^3xS^3 hypersurfaces. The generic case is analysed numerically.Comment: 23 pages, 6 figures. To appear in Annals of Global Analysis and Geometr

Seasonal Biomass and Carbohydrate Allocation Patterns in Southern Minnesota Curlyleaf Pondweed Populations

Four southern Minnesota populations of curlyleaf pondweed ( Potamogeton crispus L.) were sampled monthly from January 2001 to November 2002 to determine seasonal phenological, biomass, and carbohydrate allocation patterns. Low periods of carbohydrate storage in the seasonal phenological cycle indicate potentially vulnerable periods in the plant’s life cycle and may be the ideal time to initiate management and control efforts

Thomas-Fermi Statistical Models of Finite Quark Matter

I introduce and discuss models of finite quark matter using the formalism of the Thomas-Fermi statistical model. Similar to bag models, a vacuum energy term is introduced to model long distance confinement, but the model produces bound states from the residual color Coulomb attraction even in the absence of such a term. I discuss three baryonic applications: an equal mass nonrelativistic model with and without volume pressure, the ultra-relativistic limit confined by volume pressure, and a color-flavor locking massless model. These model may be extended to multi-meson and other mixed hadronic states. Hopefully, it can help lead to a better understanding of the phenomenology of high multi-quark states in preparation for more detailed lattice QCD calculations.Comment: 29 pages, 14 figures; final journal version (Nucl. Phys. A

Effect of social and psychological pressures on siblings of mentally retarded individuals

The researcher surveyed fifty families within the Shawano County, Wisconsin, area who have a mentally retarded member and at least one sibling whose age is between 7 years and 20 years or 30 years and 45 years. The purpose of this project was to ascertain what stress, both sociological and psychological, was felt by the siblings of a mentally retarded individual. The second purpose of the project was to ascertain what inference mainstreaming may have had on the generational age groups. The researcher attempted to identify the problems the sibling of a mentally retarded person felt in regard to social pressures, misconceptions, understanding the disability, and other ramifications which may have affected the sibling\u27s attitude toward the mentally retarded individual. The researcher also surveyed and interviewed area professionals to determine what problems were encountered when dealing with the siblings of the mentally retarded. The researcher found, through surveys and selected interviews, that there are, indeed, pressures felt by the sibling