Physical Sciences and Mathematics Commons^™

Resilience In Quaking Aspen: Recent Advances And Future Needs, Paul C. Rogers, C. Eisenberg, S. Clair

Wildland Resources Faculty Publications

Quaking Aspen (Populus tremuloides) sustainability is a topic of intense interest in forest ecology. Reports range from declines to persisting or increasing coverage in some areas. Moreover, there is little agreement on ultimate factors driving changes. Low aspen recruitment has been attributed to climate patterns, past management, herbivore increases, competitive interactions with conifers, predator and beaver extirpation, and livestock grazing. Several of these potential causes result from direct or indirect actions of human agency. On June 27–28, 2012 a group of leading aspen ecologists from diverse backgrounds convened at the High Lonesome Ranch in western Colorado to address the state …

The Magnitude And Mechanism Of Charge Enhancement Of Ch∙∙O H-Bonds, U. Adhikari, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Quantum calculations find that neutral methylamines and thioethers form complexes, with N-methylacetamide (NMA) as proton acceptor, with binding energies of 2–5 kcal/mol. This interaction is magnified by a factor of 4–9, bringing the binding energy up to as much as 20 kcal/mol, when a CH3+ group is added to the proton donor. Complexes prefer trifurcated arrangements, wherein three separate methyl groups donate a proton to the O acceptor. Binding energies lessen when the systems are immersed in solvents of increasing polarity, but the ionic complexes retain their favored status even in water. The binding energy is reduced when the methyl …

Gravitational Gauge Theory And The Existence Of Time, James Thomas Wheeler

All Physics Faculty Publications

General relativity may be formulated as a gauge theory more than one way using the quotient manifold approach. We contrast the structures that arise in four gravitational gauge theories, three of which give satisfactory gauge theoris of general relativity. Of particular interest is the quotient of the conformal group of a flat space by its Weyl subgroup, which always has natural symplectic and metric structures in addition to the requisite manifold. This quotient space admits canonically conjugate, orthogonal, metric submanifolds distinct from the original space if and only if the original flat space has signature n, -n or 0. In …

Freestores: What, Why, And How, T. Durr, Roslynn Brain

Environment and Society Faculty Publications

Everyone seems to generate some sort of unwanted possession over the years, whether it be clothes they no longer wear, appliances they no longer use, or books they no longer read. While throwing unwanted items like this away in the trash is convenient and simple, it adds to the amount of solid waste found in landfills and the natural environment. Furthermore, it wastes potentially valuable resources that could be used by others.

A viable alternative to disposing of unwanted possessions in the trash is to donate them to a freestore to be used by others, or if one does not …

Designing Your Home For Maximum Natural Lighting, P. Bytheway, Roslynn Brain

Environment and Society Faculty Publications

There are many benefits to having more natural light in your home. The most obvious of these are the savings you can achieve with a reduced utility bill. According to the U.S. Department of Energy (2012), about 10% of household electricity usage comes from lighting. The more natural light you have in your house, the less lights you have to turn on, and the less electricity you use. Another benefit, also related to energy use, is natural light can help heat homes. One of the best reasons to design your home for natural light involves the health benefits gained through …

Response Of A Small Population Of Greater Sage-Grouse To Tree Removal: Implications Of Limiting Factors, S. Nicole Frey, Rachel Curtis, Kevin Heaton

Human–Wildlife Interactions

In Utah, greater sage-grouse (Centrocercus urophasianus; hereafter, sage-grouse) range has been reduced to 50% of what is considered historical availability due to habitat degradation and loss. In an effort to improve sage-grouse habitat in southern Utah, the U.S. Bureau of Land Management (BLM) conducted a tree-removal treatment in 2005. We conducted a study to determine if (a) the tree-removal treatment was effective at creating new sage-grouse habitat, and (b) if characteristics of used habitat were similar to those reported in previous literature. The treatment resulted in increased abundance of grasses and forbs. Additionally, shrub percentage cover and height …

Response To Perryman Comment On Siemer Et Al. (2013), William F. Siemer, Daniel J. Decker, Sandra A. Jonker

Human–Wildlife Interactions

No abstract provided.

Galaxy Inclination And Surface Brightness, Jordan C. Rozum, Shane L. Larson

Student Showcase

The distribution of spiral and bar galaxy inclination angles is expected to be uniform. However, analysis of several major galaxy catalogs shows this is not the case; galaxies oriented near edge-on are significantly more common in these catalogs. In an attempt to explain this discrepancy, we have developed a galaxy simulation code to compute the appearance of a spiral type galaxy as a function of its morphological parameters. We examine the dependence of observed brightness upon inclination angle by using smooth luminous mass density and interstellar medium (ISM) density distributions. The luminous mass component is integrated along a particular line …

Curds And Whey: Little Miss Muffit's Contribution To Multivariate Linear Regression, John Cameron Kidd

Undergraduate Honors Capstone Projects

A common multivariate statistical problem is the prediction of two or more response variables using two or more predictor variables. The simplest model for this situation is the multivariate linear regression model. The standard least squares estimation for this model involves regressing each response variable separately on all the predictor variables. Breiman and Friedman [1] show how to take advantage of correlations among the response variables to increase the predictive accuracy for each of the response variable with an algorithm they call Curds and Whey. In this report, I describe an implementation of the Curds and Whey algorithm in …

Carrier Capture Dynamics Of Single Ingaas/Gaas Quantum-Dot Layers, K. N. Chauhan, D. Mark Riffe, E. A. Everett, D. J. Kim, H. Yang, F. K. Shen

All Physics Faculty Publications

Using 800 nm, 25-fs pulses from a mode locked Ti:Al₂O₃ laser, we have measured the ultrafast opticalreflectivity of MBE-grown, single-layer In_0.4Ga_0.6As/GaAs quantum-dot (QD) samples. The QDs are formed via two-stage Stranski-Krastanov growth: following initial InGaAs deposition at a relatively low temperature, self assembly of the QDs occurs during a subsequent higher temperature anneal. The capture times for free carriers excited in the surrounding GaAs (barrier layer) are as short as 140 fs, indicating capture efficiencies for the InGaAs quantum layer approaching 1. The capture rates are positively correlated with initial InGaAs thickness and …

Carrier Capture Dynamics Of Single Ingaas/Gaas Quantum-Dot Layers, Kripa N. Chauhaun, D. Mark Riffe, Addison E. Everett, D. J. Kim, H Yang, F. K. Shen

All Physics Faculty Publications

Using 800nm, 25-fs pulses from a mode locked Ti:Al2O3 laser, we have measured the ultrafast optical reflectivity of MBE-grown, single-layer In0.4Ga0.6As/GaAs quantum-dot (QD) samples. The QDs are formed via two-stage Stranski-Krastanov growth: following initial InGaAs deposition at a relatively low temperature, self assembly of the QDs occurs during a subsequent higher temperature anneal. The capture times for free carriers excited in the surrounding GaAs (barrier layer) are as short as 140fs, indicating capture efficiencies for the InGaAs quantum layer approaching 1. The capture rates are positively correlated with initial InGaAs thickness and annealing temperature. With increasing excited carrier density, the …

Occurrence And Success Of Greater Sage-Grouse Broods In Relation To Insect-Vegetation Community Gradients, Seth M. Harju, Chad V. Olson, Lisa Foy-Martin, Stephen L. Webb, Matthew R. Dzialak, Jeffrey B. Winstead, Larry D. Hayden-Wing

Human–Wildlife Interactions

A community-level approach to identify important brood habitats of greater sage-grouse (Centrocercus urophasianus) may prove useful in guiding management actions because it acknowledges that important habitat components are not ecologically independent from each other. We used principal components analysis to combine insect and vegetation variables into community gradients and used logistic regression to link these components with brood survival and occurrence. We found that brood success was higher when broods occurred in specific insect-vegetation community types. A relationship between brood occurrence and insect-vegetation gradients was not apparent. The high resolution of the data and the solid validation performance …

Stakeholder Contemporary Knowledge Needs Regarding The Potential Effects Of Tall Structures On Sage-Grouse, Terry A. Messmer, Robert Hasenyager, James Burruss, Sherry Liguori

Human–Wildlife Interactions

The U.S. Energy Policy Act of 2005 required all state and federal agencies to grant utilities access permits to promote reliable, renewable energy production and transmission. Contemporary transmission relies largely on above-ground electric transmission structures and lines. The construction, operation, and maintenance of tall structures, such as power lines, communication towers, wind turbines, and other installations and their associated activities in sage-grouse (Centrocercus spp.) habitats were identified as a conservation threat by the U.S. Fish and Wildlife Service in its decision to designate greater sage-grouse (C. urophasianus; hereafter, sage-grouse) as a candidate species for protection under the Endangered …

Livestock Predation By Common Leopard In Binsar Wildlife Sanctuary, India: Human-Wildlife Conflicts And Conservation Issues, Chandra Prakash Kala, Kishor Kumar Kothari

Human–Wildlife Interactions

We investigate livestock predation by the common leopard (Panthera pardus) and emerging conflicts between this species, local people, and wildlife authorities at the Binsar Wildlife Sanctuary in the Himalayan region of India. We scrutinized secondary data that were collected by wildlife authorities; we also conducted informal interviews of villagers living within sanctuary, and wildlife staff to understand various human–leopard conflicts. Leopard density was approximately 0.33/km2 in the sanctuary. Leopards killed 1,763 domestic animals, about 90% of which were cattle, during a 14-year period. Within the sanctuary, leopards killed 1 person and injured 9 others. This high depredation rate …