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Full-Text Articles in Physical Sciences and Mathematics

Source Of The Northeastern Idaho Batholith: Isotopic Evidence For A Paleoproterozoic Terrane In The Northwestern U.S., Paul A. Mueller, Robert Duncan Shuster, K. A. D'Arcy, A. L. Heatherington, A. P. Nutman, I. S. Williams Jan 1995

Source Of The Northeastern Idaho Batholith: Isotopic Evidence For A Paleoproterozoic Terrane In The Northwestern U.S., Paul A. Mueller, Robert Duncan Shuster, K. A. D'Arcy, A. L. Heatherington, A. P. Nutman, I. S. Williams

Geography and Geology Faculty Publications

The northeastern portion of the Idaho batholith (NIB) intruded Proterozoic rocks of the Belt-Purcell supergroup between SO and 90 Ma. Whole-rock Sm-Nd isotopic analyses of batholithic rocks yield depleted mantle model ages (T oM) between 1. 72 and 1.93 Ga and values of eNd between -17. 7 and - 21.2, similar to associated metamorphic rocks and within the range for Belt-Purcell sedimentary rocks. Premagmatic zircons from one sample of the NIB were analyzed individually using the SHRIMP ion microprobe and yielded a single age population at 1.74 Ga. This apparently single-aged source contrasts with the range of ages reported for …


Strontium Isotope Stratigraphy And Age Estimates For The Leisey Shell Pit Faunas, Hillsborough County, Florida, Douglas S. Jones, Paul A. Mueller, Teresa Acosta, Robert Duncan Shuster Jan 1995

Strontium Isotope Stratigraphy And Age Estimates For The Leisey Shell Pit Faunas, Hillsborough County, Florida, Douglas S. Jones, Paul A. Mueller, Teresa Acosta, Robert Duncan Shuster

Geography and Geology Faculty Publications

The vertebrate fauna of the Leisey Shell Pit near Tampa Bay, Florida, represents one of the more significant lrvingtonian mammalian faunas of North America. The fossil vertebrates occur in thin bone beds bounded above and below by massive shell beds containing a rich invertebrate ( chiefly molluscan) fauna. Debate has arisen concerning the precise age of the faunas at Leisey. Although generally agreed to be Pleistocene, estimates based upon vertebrate biostratigraphy suggest a somewhat older age than do estimates based upon molluscan biostratigraphy. To help resolve this controvefliy, 87Sr/86Sr ratios were determined on molluscan shells throughout the …


Quantitative Object Motion Prediction By An Art2 And Madaline Combined Neural Network: Concepts And Experiments, Qiuming Zhu, Ahmed Y. Tawfik Jan 1995

Quantitative Object Motion Prediction By An Art2 And Madaline Combined Neural Network: Concepts And Experiments, Qiuming Zhu, Ahmed Y. Tawfik

Computer Science Faculty Publications

An ART2 and a Madaline combined neural network is applied to predicting object motions in dynamic environments. The ART2 network extracts a set of coherent patterns of the object motion by its self-organizing and unsupervised learning features. The identified patterns are directed to the Madaline network to generate a quantitative prediction of the future motion states. The method does not require any presumption of the mathematical models, and is applicable to a variety of situations.


Cs2ga2o(Bo3)2, Robert W. Smith Jan 1995

Cs2ga2o(Bo3)2, Robert W. Smith

Chemistry Faculty Publications

The structure of dicaesium digallium diorthoborate oxide constitutes a new type of oxide borate. It consists of a three-dimensional gallium-oxide-orthoborate lattice with Cs atoms occupying large cavities in the lattice. This lattice is made from pairs of Ga atoms connected through a shared O atom along the [001] direction; these Ga dimers are interconnected through shared O vertices to trigonal BO3 groups along the [010], [110] and [i10] directions, completing the tetrahedral coordination environment of each Ga atom.


Galois Module Structure Of Ideals In Wildly Ramified Cyclic Extensions Of Degree P2, Gove Griffith Elder Jan 1995

Galois Module Structure Of Ideals In Wildly Ramified Cyclic Extensions Of Degree P2, Gove Griffith Elder

Mathematics Faculty Publications

For L/K, any totally ramified cyclic extension of degree p2 of local fields which are finite extensions of the field of p-adic numbers, we describe the Zp[Gal(L/K)]-module structure of each fractional ideal of L explicitly in terms of the 4p+1 indecomposable Zp[Gal(L/K)]-modules classified by Heller and Reiner. The exponents are determined only by the invariants of ramification.


Spectral Properties Of Operators Having Dense Orbits, Valentin Matache Jan 1995

Spectral Properties Of Operators Having Dense Orbits, Valentin Matache

Mathematics Faculty Publications

In the following H will denote a separable, infinite-dimensional, complex Hilbert space. The term operator will always mean linear, bounded operator on H. By invariant subspace we mean closed, invariant linear manifold. For a given operator T, the set of all invariant subspaces of T will be denoted LatT, since obviously it is a lattice. The set of all operators commuting with T is denoted {T}'. A subspace will be called hyperinvariant for T if it is invariant under any operator in {T}'.