Physical Sciences and Mathematics Commons^™

Canonical Thurston Obstructions, Kevin M. Pilgrim

Mathematics and Statistics Faculty Research & Creative Works

We refine Douady and Hubbard's proof of Thurston's topological characterization of rational functions by proving the following theorem. Let f: S2→S2 be a branched covering with finite postcritical set Pf and hyperbolic orbifold. Let Γc denote the set of all homotopy classes γ of nonperipheral, simple closed curves in S2-Pf such that the length of the unique geodesic homotopic to γ tends to zero under iteration of the Thurston map induced by f on Teichmüller space. Then either Γc is empty, and f is equivalent to a rational function, or else Γc is a Thurston obstruction. © 2001 Academic Press.

Lake Whatcom Monitoring Project 1999/2000 Report, Robin A. Matthews, Michael Hilles, Joan Vandersypen, Robert J. Mitchell, Geoffrey B. Matthews

Lake Whatcom Annual Reports

This report is part of an on-going series of annual reports and special project reports that document the Lake Whatcom monitoring program.

This work is conducted by the Institute for Watershed Studies and other departments at Western Washington University. The major objective of this program is to provide long-term baseline water quality monitoring in Lake Whatcom and selected tributaries. Each section contains brief explanations about the water quality data, along with discussions of patterns observed in Lake Whatcom.

Burning And Burying In Connecticut: Are Regional Solutions To Solid Waste Disposal Equitable?, Timothy Black, John A. Stewart

New England Journal of Public Policy

To comply with federal legislation, states throughout the country are replacing old town dumps with a regional system for municipal solid waste disposal.This system includes trash-to-energy incinerators and ash landfills as well as recycling and reduction facilities. While these new types of facilities are expected to be environmentally safer, they have concentrated the disposal process of waste generated throughout the state in fewer locations. State leaders champion the use of newer, cleaner disposal methods, while local community groups complain that they have become the dumping grounds for the state. This is the first environmental equity study to examine whether these …

Nitrogen And Phosphorus Use Efficiency In Stands Of Loblolly And Slash Pine, Christopher Dicus, Thomas J. Dean

Natural Resources Management and Environmental Sciences

Nitrogen and phosphorus use efficiency (NUE and PUE, respectively), the annual amount of stemwood produced per unit net N or P used in total aboveground production, were examined in 17-year-old pure stands of unthinned loblolly pine (Pinus taeda L.) and slash pine (Pinus elliottii Englem.) planted at two spacings. Slash pine stands had a greater NUE and PUE than loblolly pine, which was attributed to greater relative allocation of aboveground production to stemwood, lower foliar N and P concentrations, and greater foliar retranslocation of N and P by slash pine. Compared to 2.4 x 2.4 meter spaced stands, …

Experimental Observation Of Rainbow Scattering By A Coated Cylinder: Twin Primary Rainbows And Thin-Film Interference, Charles L. Adler, James A. Lock, Justin K. Nash, Kirk W. Saunders

Physics Faculty Publications

We experimentally examine the primary rainbow created by the illumination of a coated cylinder. We present a simple technique for varying the coating thickness over a wide range of values, and we see evidence for two different scattering regimes. In one, where the coating thickness is large, twin rainbows are produced. In the second, where the coating is thin enough to act as a thin film, a single rainbow is produced whose intensity varies periodically as the coating thickness varies. We find good agreement with previous theoretical predictions. (C) 2001 Optical Society of America.

Hidden Markov Models For Visual Speech Synthesis In Limited Data, Harold A. Arb

Theses and Dissertations

This work presents a new approach for estimating control points (facial locations that control movement) to allow the artificial generation of video with apparent mouth movement (visual speech) time-synced with recorded audio. First, Hidden Markov Models (HMMs) are estimated for each visual speech category (viseme) present in stored video data, where a category is defined as the mouth movement corresponding to a given sound and where the visemes are further categorized as trisemes (a viseme in the context of previous and following visemes). Next, a decision tree is used to cluster and relate states in the HMMs that are similar …

Rocky Mountain Wolf Recovery 2001 Annual Report

Rocky Mountain Wolf Recovery: Annual Reports

Wolves in the Northern Rocky Mountains (Idaho, Montana and Wyoming) continue to increase in distribution and numbers (Figures 1,5). Estimates of wolf numbers at the end of 2001 were 261 wolves in the Central Idaho Recovery Area, 218 in the Greater Yellowstone Recovery Area, and 84 in the Northwest Montana Recovery Area (Figure 1, Tables 1,2,3,4). By state boundaries, there were an estimated 251 wolves in the state of Idaho, 189 in Wyoming and 123 in Montana. Of the 63 groups of 2 or more wolves, at least 34 wolf packs met the definition of “breeding pair,” an adult male …

Ratio Of Jet Cross Sections At √S = 630 Gev And 1800 Gev, B. Abbott, Gregory R. Snow, D0 Collaboration

Gregory Snow Publications

The D0 Collaboration has measured the inclusive jet cross section in p̅p collisions at √s = 630 GeV. The results for pseudorapidities ∣η∣ < 0.5 are combined with our previous results at √s =1800 GeV to form a ratio of cross sections with smaller uncertainties than either individual measurement. Next-to-leading-order QCD predictions show excellent agreement with the measurement at 630 GeV; agreement is also satisfactory for the ratio. Specifically, despite a 10% to 15% difference in the absolute magnitude, the dependence of the ratio on jet transverse momentum is very similar for data and theory.

Little Venice Water Quality Monitoring Quarterly Reports #3 & 4, Ronald Jones, Joseph N. Boyer

SERC Research Reports

No abstract provided.

The Stable Manifold Theorem For Stochastic Differential Equations (Dynamical Systems And Probability Seminar, Loughborough University), Salah-Eldin A. Mohammed

Miscellaneous (presentations, translations, interviews, etc)

No abstract provided.

Little Languages And Their Programming Environments, John Clements, Paul Graunke, Shriram Krishnamurthi, Matthias Felleisen

Computer Science and Software Engineering

Programmers constantly design, implement, and program in little languages. Two different approaches to the implementation of little languages have evolved. One emphasizes the design of little languages from scratch, using conventional technology to implement interpreters and compilers. The other advances the idea of extending a general-purpose host language; that is, the little language shares the host language's features (variables, data, loops, functions) where possible; its interpreters and compilers; and even its type soundness theorem. The second approach is often called a language embedding.

This paper directs the attention of little language designers to a badly neglected area: the programming environments …

A New Cohomology Theory Of Orbifold, Weimin Chen Chen

Weimin Chen

No abstract provided.

The Stable Manifold Theorem For Stochastic Differential Equations (Analysis And Probability Seminar, University Of Hull), Salah-Eldin A. Mohammed

Miscellaneous (presentations, translations, interviews, etc)

No abstract provided.

An Approach To Parameterization Of The Oceanic Turbulent Boundary Layer In The Western Pacific Warm Pool, Alexander Soloviev, Roger Lukas, Peter Hacker

Marine & Environmental Sciences Faculty Articles

Vertical profiles of zonal velocity and the dissipation rate ε of the turbulent kinetic energy obtained during the Tropical Ocean-Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (COARE) are analyzed in the context of planetary boundary layer relationships previously derived from atmospheric measurements. The presence of a barrier layer and the striking effect of increased dimensionless shear and ε at the bottom of the surface mixed layer of the ocean, features often observed in the western Pacific warm pool area, are consistent with the boundary layer laws. The gradient Richardson number Ri is found to be a convenient parameter for scaling the …

First-Principles Elastic Constants And Electronic Structure Of Α-Pt2si And Ptsi, Gus L. W. Hart, O. Beckstein, J. E. Klepeis, O. Pankratov

Faculty Publications

We have carried out a first-principles study of the elastic properties and electronic structure for two room-temperature stable Pt silicide phases, tetragonal α-Pt2Si, and orthorhomic PtSi. We have calculated all of the equilibrium structural parameters for both phases; the a and c lattice constants for α-Pt2Si and the a, b, and c lattice constants and four internal structural parameters for PtSi. These results agree closely with experimental data. We have also calculated the zero-pressure elastic constants, confirming prior results for pure Pt and Si and predicting values for the six (nine) independent, nonzero elastic constants of α-Pt2Si (PtSi). These calculations …

The Geometrical Structure Of 2d Bond-Orientational Order, Mark Bowick, Alex Travesset

Physics - All Scholarship

We study the formulation of bond-orientational order in an arbitrary two dimensional geometry. We find that bond-orientational order is properly formulated within the framework of differential geometry with torsion. The torsion reflects the intrinsic frustration for two-dimensional crystals with arbitrary geometry. Within a Debye-Huckel approximation, torsion may be identified as the density of dislocations. Changes in the geometry of the system cause a reorganization of the torsion density that preserves bond-orientational order. As a byproduct, we are able to derive several identities involving the topology, defect density and geometric invariants such as Gaussian curvature. The formalism is used to derive …

Numerics Of Stochastic Systems With Memory (Applied Mathematics And Numerical Analysis Seminars, University Of Manchester), Salah-Eldin A. Mohammed

Miscellaneous (presentations, translations, interviews, etc)

No abstract provided.

Magnetic Phase Diagram Of The Diluted Metamagnet Fe0.95Mg0.05Br2, H. Aruga Katori, K. Katsumata, O. Petracic, Wolfgang Kleemann, T. Kato, Christian Binek

Christian Binek Publications

The axial magnetic phase diagram of the antiferromagnet Fe_0.95Mg_0.05Br₂ is studied by specific heat, superconducting quantum interference device, and Faraday rotation techniques. The diamagnetic impurities give rise to random-field criticality along the second-order phase line H_c(T) between T_N=13.1 K and a multicritical point at T_m≈5 K, and to a spin-flop line between T_m and the critical end-point temperature T_e≈3.5 K. The phase line H₁(T)c(T) ending at T_m is probably due to symmetric nondiagonal exchange.

Universality Classes Of Self-Avoiding Fixed-Connectivity Membranes, Mark Bowick, Angelo Cacciuto, Gudmar Thorleifsson, Alex Travesset

Physics - All Scholarship

We present an analysis of extensive large-scale Monte Carlo simulations of self-avoiding fixed-connectivity membranes for sizes (number of faces) ranging from 512 to 17672 (triangular) plaquettes. Self-avoidance is implemented via impenetrable plaquettes. We simulate the impenetrable plaquette model in both three and four bulk dimensions. In both cases we find the membrane to be flat for all temperatures: the size exponent in three dimensions is nu=0.95(5) (Hausdorff dimension d_H=2.1(1)). The single flat phase appears, furthermore, to be equivalent to the large bending rigidity phase of non-self-avoiding fixed-connectivity membranes - the roughness exponent in three dimensions is xi=0.63(4). This suggests that …

Spectroscopic Constants, Lifetimes And Predissociation Rates For Bi2A(0+U), Michael W. Dolezal

Theses and Dissertations

More than 100,000 spectral features from a Bi₂(X¹ Σ⁺_g → A(0⁺_u)) absorption spectrum, encompassing 0 ≤ v' ≤ 91, 0 ≤ v" ≤ 7 and J2(A). Ground state constants, reported by Barrow et al. [1], remain unchanged. The new constants are used to redefine the A-state potential using traditional RKR methods and to set the dissociation energy at De = 29,913 cm"1, which correlates A-state dissociation products to ⁴S + ²D atoms. A pulsed dye laser apparatus was used to obtain lifetime data for Bi₂A(0⁺_u) …

Interacting Ferromagnetic Nanoparticles In Discontinuous Co80Fe20/Al2O3 Multilayers: From Superspin Glass To Reentrant Superferromagnetism, W. Kleeman, O. Petracic, Christian Binek, G.N. Kakazei, Yu. G. Pogorelov, J.B. Sousa, Susana Cardoso De Freitas, P.P. Freitas

Christian Binek Publications

Dipolar superferromagnetism with reentrant low-temperature superspin glass behavior is observed on a randomly distributed ferromagnetic nanoparticle systems in discontinuous metal-insulator multilayers [Co₈₀Fe₂₀/Al₂O₃ (3 nm)] ₁₀ with nominal thickness 1.1<~t<~1.3 nm by use of ac susceptometry and dc magnetometry. At t=1.0 nm, superspin glass-like freezing is evidenced by the criticality of dynamic and nonlinear susceptibilities.

Icdm: An Architecture And Toolkit In Support Of Agent-Based, Decision-Support Applications, Kym J. Pohl, Jens G. Pohl

Collaborative Agent Design (CAD) Research Center

Agent-based, decision-support systems provide human decision-makers with a means of solving complex problems through collaboration with heterogeneous collections of both human and computer-based expert agents. Over the past decade the Collaborative Agent Design (CAD) Research Center has developed several proof-of-concept and production-oriented agent-based, decision-support systems for both commercial and Department of Defense applications. These applications range in domain from engineering design to tactical command and control. While diverse in application, each of these systems is predicated on the same set of fundamental principles derived from years of experience in this area. Primary among these principles are the notions of high-level …

Effect Of Primary And Secondary Repellents On European Starlings: An Initial Assessment, Roger W. Sayre, Larry Clark

United States Department of Agriculture Wildlife Services: Staff Publications

Wildlife managers need chemical repellents that are effective at deterring damage by birds, but these repellents must be environmentally and toxicologically safe. The number of commercially available bird repellents has been reduced because of concerns about environmental safety. Currently, there are 2 categories of avian repellents. Chemicals that are reflexively avoided by birds because they irritate the peripheral chemical senses are referred to as primary repellents. Chemicals that cause gastrointestinal illness and learned avoidance of ancillary sensory cues that are paired with the illness are known as secondary repellents. Secondary repellents most often identified as the most effective avian repellents …

Monitoring Of Terrestrial Carnivore Populations, Eric M. Gese

United States Department of Agriculture Wildlife Services: Staff Publications

There is increasing concern about the status and distribution of terrestrial carnivore populations throughout the world (Schaller, 1996). Changes in land-use practices, habitat loss and fragmentation, sanctioned human persecution, declines in natural prey, disease, illegal poaching, and increased competition within carnivore guilds have brought about a general decline in several carnivore populations with some species now occupying a fragment of their former range. The continued loss of suitable habitat due to an ever expanding human population has placed the issue of conservation and protection of some carnivores as a top environmental priority and/or controversy for many agencies and organizations. Paramount …

Porcine Zona Pellucida Immunocontraception: Long-Term Health Effects On White-Tailed Deer, Lowell A. Miller, Ken Crane, Stan Gaddis, Gary J. Killian

United States Department of Agriculture Wildlife Services: Staff Publications

As part of a 9-year study on the contraceptive effects of Porcine Zona Pellucida (PZP) on white-tailed deer (Odocoileus virginianus), we analyzed serum chemistry panels during the first 4 years. This included the first 2 years when does were being actively immunized, and 2 years post-immunization. The chemistry panel was designed to detect pathologies that might result from the immunization of the deer. Blood chemistry results did not suggest any pathological changes resulting from the immunization. Seasonal differences in serum cholesterol were similar in both the control and PZP-treated groups. Seasonal changes in the mean body weights of …

Impacts Of Supplemental Feeding On The Nutritional Ecology Of Black Bears, Steven T. Partridge, Dale L. Nolte, Georg J. Ziegltrum, Charles T. Robbins

United States Department of Agriculture Wildlife Services: Staff Publications

Black bear (Ursus americanus) damage to managed conifer stands during the spring in the U.S. Pacific Northwest is a continuing management concern. Because bear damage to managed conifers may reflect the limited availability of nutritious foods, supplemental feeding has been used to decrease damage. Highly palatable, pelleted feed is provided ad libitum from April until late June when berries ripen and such damage stops. We examined black bear use of supplemental feed during the spring and summer of 1998 and 1999 in western Washington. Bears were captured in areas where supplemental feed was provided and in control areas …

Use Of Acetaminophen For Large-Scale Control Of Brown Treesnakes, Peter J. Savarie, John A. Shivik, Gary C. White, Jerome C. Hurley, Larry Clark

United States Department of Agriculture Wildlife Services: Staff Publications

Because the brown treesnake (Boiga irregularis) has virtually extirpated the avifauna on Guam and is a threat to other Pacific islands, the development of alternative and efficient control methods is required. Therefore, we performed a large-scale field experiment to determine whether the acetaminophen baits we developed could be used to reduce population levels of brown treesnakes on Guam. Toxic baits were made by inserting 80 mg of acetaminophen into dead neonatal mice, and these mouse baits were used to treat plots. Reference plots were baited with unadulterated baits. We used mark-recapture methods to estimate snake abundance on plots …

Black Bear Forest Damage In Washington State, Usa: Economic, Ecological, Social Aspects, Georg J. Ziegltrum, Dale L. Nolte

United States Department of Agriculture Wildlife Services: Staff Publications

Black bear (Ursus americanus) damage to coniferous forests can be detrimental to the forest products industry in Washington state. Value of timber damage, west of the Cascade Mountains is millions of dollars every year. The Washington Forest Protection Association’s (WFPA) Animal Damage Control Program (ADCP) manages bear damage in cooperation with the Washington Department of Fish and Wildlife (WDFW). Bears can significantly affect the viability of other wildlife, for example, elk (Cervus elaphus) calf predation on calving sites. Conversely, bear-damaged trees add to the snags and dead wood on the ground, which provide important habitat and …

Broken Supersymmetric Shape Invariant Systems And Their Potential Algebras, Asim Gangopadhyaya, Jeffrey Mallow, Uday P. Sukhatne

Physics: Faculty Publications and Other Works

Although eigenspectra of one dimensional shape invariant potentials with unbroken supersymmetry are easily obtained, this procedure is not applicable when the parameters in these potentials correspond to broken supersymmetry, since there is no zero energy eigenstate. We describe a novel two-step shape invariance approach as well as a group theoretic potential algebra approach for solving such broken supersymmetry problems.

Evolution Of River Dolphins, Healy Hamilton, Susana Caballero, Allen G. Collins, Robert L. Brownell Jr.

United States Department of Commerce: Staff Publications

The world's river dolphins (Inia, Pontoporia, Lipotes and Platanista) are among the least known and most endangered of all cetaceans. The four extant genera inhabit geographically disjunct river systems and exhibit highly modified morphologies, leading many cetologists to regard river dolphins as an unnatural group. Numerous arrangements have been proposed for their phylogenetic relationships to one another and to other odontocete cetaceans. These alternative views strongly affect the biogeographical and evolu- tionary implications raised by the important, although limited, fossil record of river dolphins. We present a hypothesis of river dolphin relationships based on phylogenetic analysis of three …