Physical Sciences and Mathematics Commons^™

Dynamics Of Electron Wave Propagation In Photoionization Microscopy: I. Semiclassical Open-Orbit Theory, L. B. Zhao, John B. Delos

Arts & Sciences Articles

This is the first of two papers that develop theories and numerical methods for photoionization microscopy of hydrogen atoms in strong electric fields, in semiclassical and quantum-mechanical frameworks, respectively. In this paper, semiclassical open-orbit theory is presented to describe the propagation of outgoing electron waves to macroscopic distances. Spatial distributions of electron probability densities and current densities are predicted. The open-orbit theory, based on an assumption that electron waves propagate along classical paths from a pointlike source to a detector, provides a clear and intuitive physical picture to interpret structures of observed geometrical interference patterns in photoionization microscopy. We calculate …

Draft Management Plan For The Gascoyne Demersal Scalefish Managed Fishery, Department Of Fisheries Western Australia

Fisheries management papers

As part of the Outcomes of the Wetline Review released in 2007 (Fisheries Management Paper 224) the then Minister for Fisheries approved the drafting of the Gascoyne Demersal Scalefish Fishery Management Plan (the Plan). The Hon Norman Moore MLC, Minister for Fisheries re-approved those decisions in 2009. The draft Plan will supersede the Shark Bay Snapper Management Plan 1994.

The Department intends to introduce the first phase of the Plan by 1 September 2010, at which time the Shark Bay Snapper Management Plan 1994 would be revoked and replaced by the new Plan. The (non pink snapper) demersal scalefish effort …

Ground Surface Deformation Patterns, Magma Supply, And Magma Storage At Okmok Volcano, Alaska, From Insar Analysis: 1. Inter-Eruption Deformation, 1997-2008, Zhong Lu, Daniel Dzurisin, Juliet Biggs, Charles Wicks Jr., Stephen R. Mcnutt

School of Geosciences Faculty and Staff Publications

Starting soon after the 1997 eruption at Okmok volcano and continuing until the start of the 2008 eruption, magma accumulated in a storage zone centered ∼3.5 km beneath the caldera floor at a rate that varied with time. A Mogi-type point pressure source or finite sphere with a radius of 1 km provides an adequate fit to the deformation field portrayed in time-sequential interferometric synthetic aperture radar images. From the end of the 1997 eruption through summer 2004, magma storage increased by 3.2–4.5 × 10⁷ m³, which corresponds to 75–85% of the magma volume erupted in 1997. …

Tuning Quantum Dots Optical Properties By Temperature And Concentration Modulation, Amber Sexton

Renée Crown University Honors Thesis Projects - All

Quantum dots have recently been awarded attention due to their tunable optical and spectroscopic properties. The optical and spectroscopic behavior of quantum dots was investigated as a function of mean particle size. Manipulation of the reaction conditions and constituents impact the controllability of size and surface conditions. Therefore, synthesis of CdSe and CdS semiconductor nanoparticles with tunable particle size were created using temperature, time, and composition as variables. Analytical techniques used to characterize the nanoparticles included fluorescence and electronic absorption. The effect of temperature, aside from changing the size of the particle, also eliminated defects on the surface and caused …

A Discriminative Model Approach For Accurate Duplicate Bug Report Retrieval, Chengnian Sun, David Lo, Xiaoyin Wang, Siau-Cheng Khoo

Research Collection School Of Computing and Information Systems

Bug repositories are usually maintained in software projects. Testers or users submit bug reports to identify various issues with systems. Sometimes two or more bug reports correspond to the same defect. To address the problem with duplicate bug reports, a person called a triager needs to manually label these bug reports as duplicates, and link them to their "master" reports for subsequent maintenance work. However, in practice there are considerable duplicate bug reports sent daily; requesting triagers to manually label these bugs could be highly time consuming. To address this issue, recently, several techniques have be proposed using various similarity …

Efficient Unidirectional Proxy Re-Encryption, Sherman Chow, Weng Jian, Yanjiang Yang, Robert H. Deng

Research Collection School Of Computing and Information Systems

Proxy re-encryption (PRE) allows a semi-trusted proxy to convert a ciphertext originally intended for Alice into one encrypting the same plaintext for Bob. The proxy only needs a re-encryption key given by Alice, and cannot learn anything about the plaintext encrypted. This adds flexibility in various applications, such as confidential email, digital right management and distributed storage. In this paper, we study unidirectional PRE, which the re-encryption key only enables delegation in one direction but not the opposite. In PKC 2009, Shao and Cao proposed a unidirectional PRE assuming the random oracle. However, we show that it is vulnerable to …

Global Project Management: Pedagogy For Distributed Teams, Benjamin Kok Siew Gan, Randy Weinberg, Selma Limam Mansar

Research Collection School Of Computing and Information Systems

This paper reflects on pedagogy for teaching collaborative global projects across universities in different countries. Over a period of four years, students at three universities - one in the United States, one in Singapore and one in the Middle East - enrolled in a course called "Global Project Management". In this course, coordinated across locations, students experience a global project with distant team members. We describe the course experience and student perceptions of the requisite skills, collaboration tools and challenges bearing on effective global project work.

Observing And Modeling The Nocturnal Park Cool Island Of An Arid City: Horizontal And Vertical Impacts, Winston T. L. Chow, Ronald L. Pope, Anthony J. Brazel

Research Collection School of Social Sciences

We examined the horizontal and vertical nocturnal cooling influence of a small park with irrigated lawn and xeric surfaces (∼3 ha) within a university campus of a hot arid city. Temperature data from 0.01- to 3-m heights observed during a bicycle traverse of the campus were combined with modeled spatial temperature data simulated from a three-dimensional microclimate model (ENVI-met 3.1). A distinct park cool island, with mean observed magnitudes of 0.7–3.6°C, was documented for both traverse and model data with larger cooling intensities measured closer to surface level. Modeled results possessed varying but generally reasonable accuracy in simulating both spatial …

Petrogenesis Of The Greenwater Range: Comparison To The Crater Flat Volcanic Field And Implications For Hazard Assessment, Ashley Kaye Tibbetts

UNLV Theses, Dissertations, Professional Papers, and Capstones

Pliocene basalts of the Greenwater Range, California erupted from 24 volcanic vents now represented by volcanic plugs, craters and scoria mounds. Basaltic magmas originated in the asthenospheric mantle, but show evidence of a lithospheric component. Depths and temperatures of melting calculated using a silica activity geobarometer are 54.3–89.6 km and 1367-1435oC, placing melting in the asthenosphere. The preferred petrogenetic model involves melting of lithospheric mantle thermally and mechanically, but not chemically, converted to asthenospheric mantle. Melting depths correspond to low velocity zones in the mantle as revealed in seismic profiles. Chemical and lithologic similarities between basalt in the Greenwater Range …

An Experimental Investigation Of Chemical Mass Transfer Processes In Crystallizing, Hydrous Silicate Magmas: The Genesis Of Ore Deposits And Metasomatic Fluids, Aaron S. Bell

UNLV Theses, Dissertations, Professional Papers, and Capstones

This dissertation is comprised of three broadly related experimental petrology projects on phase equilibria and noble metal solubility in hydrous silicate melts. Chapters two and three combine experimental petrology with high precision laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis of experimental run products in order to quantitatively constrain the behavior of the investigated metals. Chapter four presents experimental evidence detailing a novel oxidation mechanism for degassing silicate liquids as well as exploring the geochemical consequences of the proposed mechanism.

Chapter two presents the results of an experimental study on Au, Pt, and Pd behavior in coexisting silicate melt-sulfide-oxide …

Phyllosilicate Mineralogy, 40ar/39ar Geochronology, And Genesis Of Petrocalcic Soils In The Southwest U.S.A., Colin R. Robins

UNLV Theses, Dissertations, Professional Papers, and Capstones

Obtaining isotope ages for arid soils and paleosols, including carbonate-cemented (calcic and petrocalcic) horizons, constitutes a significant challenge for soil scientists, geomorphologists, and stratigraphers. Carbonate-cemented soils foster diverse suites of authigenic minerals with exciting potential for geochronology, however, this potential has not been realized. This dissertation describes the timing of pedogenic palygorskite and sepiolite crystallization in extremely old, extant petrocalcic soils of the southwest U.S.A., and assumes that these fibrous, high-magnesium phyllosilicates contain sufficient lattice-bound K to warrant vacuum-encapsulated 40Ar/39Ar geochronology. This three-part study evaluated the (1) selective extraction, (2) 40Ar/39Ar analysis, and (3) pedogenesis of palygorskite and sepiolite.

Effects …

Fire On The Mountain: Growth And Conflict In Colorado Ski Country, Michael W. Childers

UNLV Theses, Dissertations, Professional Papers, and Capstones

This dissertation examines the environmental, economic, and cultural conflicts over the private development of ski resorts in Colorado's National Forests between 1910 and 2000. Downhill skiing emerged as an increasingly popular winter activity during the first half of the twentieth century, particularly in western state such as Colorado. A part of the a larger outdoor recreational boom throughout the United States' during the interwar years, downhill skiing challenged the Forest Service's ability to meeting the public's growing appetite for year-round recreational opportunities. These challenges increased following World War II as the nation's growing population and affluence drew millions to their …

A Comparative Study On Text Categorization, Aditya Chainulu Karamcheti

UNLV Theses, Dissertations, Professional Papers, and Capstones

Automated text categorization is a supervised learning task, defined as assigning category labels to new documents based on likelihood suggested by a training set of labeled documents. Two examples of methodology for text categorizations are Naive Bayes and K-Nearest Neighbor.

In this thesis, we implement two categorization engines based on Naive Bayes and K-Nearest Neighbor methodology. We then compare the effectiveness of these two engines by calculating standard precision and recall for a collection of documents. We will further report on time efficiency of these two engines.

A Visualization Approach For Message Passing In Parallel Computing Systems, Arunkumar Sadasivan

UNLV Theses, Dissertations, Professional Papers, and Capstones

Information Visualization has been used as an effective method in transforming textual information into a visual form that enables users to effectively communicate and understand the information. MPI (Message Passing Interface) usually involves a large amount of data, which necessitates exploring innovative ideas to visualize such data effectively.

In this thesis, we implement a graph visualization tool called MPROV to effectively visualize communication patterns of message passing using log files from MPI applications. The tool provides several interaction techniques to effectively reduce the amount of data displayed on the screen. We have also developed protocol conformance checking, which verifies the …

Antimicrobial Activity Of D-Lenolate®, Andy Phui

UNLV Theses, Dissertations, Professional Papers, and Capstones

Olive trees are one of the most important fruit trees in the Mediterranean. Although not validated by research, olive leaves are traditionally believed to fight off fever and infections. It has been shown that olive leaf extracts possess antimicrobial activity. Olive leaf extracts contain polyphenols. One of the major phenolic compounds is oleuropein. Oleuropein and other polyphenols have been shown to exhibit antimicrobial activity. East Park Research (EPR) developed an extraction process that they claim does not alter the chemical composition of the olive leaves. The extract is known by the commercial name d-lenolate®. Studies have provided evidence that d-lenolate®, …

Characterization Of Plutonium Particles Originating From The Bomarc Accident -1960, Richard Charles Gostic

UNLV Theses, Dissertations, Professional Papers, and Capstones

Within the U.S. arsenal, 32 accidents with nuclear weapons were reported between 1950 and 1980. One of these accidents occurred at McGuire AFB in 1960. A BOMARC missile armed with a nuclear warhead caught on fire and as a result the warhead was destroyed. Sub-millimeter particles consisting of weapons grade plutonium (WGPu) produced by this accident were distributed around the site and remained in the environment for 47 years. Soil cores known to contain WGPu particles produced by this accident were obtained. The particles were localized and removed from the soil with the aid of high resolution computed tomography. The …

An Exploratory Study On Energy Consumption Of Energy Star And Non-Energy Star Homes, Prajakta Kulkarni

UNLV Theses, Dissertations, Professional Papers, and Capstones

The reduction of energy consumption is one of the economic necessities in the United States due to depleting energy sources in the world. The construction industry is stepping forward to reduce the energy consumption of buildings by efficient designs or by constructing buildings with energy efficient materials and features. In 1992, the U.S. Environmental Protection Agency (EPA) and Department of Energy (DOE) introduced the Energy Star Program to promote energy efficient products with the same or improved services. According to the EPA, Energy Star homes, which use these products, will consume 20 to 30 percent less energy than non-Energy Star …

Partial Phonon Density Of States Of 57-Iron And 161-Dysprosium In Dyfe3 By Nuclear Resonant Inelastic X-Ray Scattering Under High Pressure, Elizabeth Anne Tanis

UNLV Theses, Dissertations, Professional Papers, and Capstones

The dual partial phonon density of states (DOS) from two different Mossbauer isotopes (161Dy and 57Fe) in the same material (DyFe3) was successfully measured using the nuclear resonant inelastic x-ray scattering (NRIXS) technique at high pressure. Nuclear inelastic scattering measurements yield an in-depth understanding of the element-specific dynamic properties. The Debye temperatures , the Lamb-Mossbauer factor, and the vibrational contributions to the Helmholtz free energy, specific heat , entropy and internal energy are calculated directly from the phonon density of states.

The Integration Of Biomimicry Into A Built Environment Design Process Model: An Alternative Approach Towards Hydro-Infrastructure, Timothy Lee Albertson

UNLV Theses, Dissertations, Professional Papers, and Capstones

Current methods and processes that support the planning, design and construction of a sustainable built environment include ambiguous principles (Roseland 2000), lack feedback loops (Van Bueren and Jong 2007) and lack a common language between disciplines (Brandon et al 1997). As a result of 3.8 billion years of "research and development" (evolution), nature provides a set of design blueprints that may be used to guide us to create elegant, sustainable, and innovative designs for human technologies (Benyus 1997). The field of biomimicry analyzes nature's best ideas and adapts them for human use (Benyus 1997). The built environment could benefit from …

Ion-Exchange (Ix): Arsenic And Chromium Removal From Brines And Removal Of Inorganic Contaminants By Specialty Resins, Behrang Pakzadeh

UNLV Theses, Dissertations, Professional Papers, and Capstones

Although ion exchange is highly efficient in removing inorganic contaminants, similar to other water treatment technologies, ion exchange has some drawbacks that need to be studied further. Three issues related to drawbacks of ion-exchange resins in water treatment were addressed in this research. The first issue was the influence of anionic inorganic co-contaminants including nitrate, Cr(VI), Se(VI), and As(V) on the performances of nitrate and perchlorate specialty (selective) resins in water treatment. It was found that nitrate can be removed from waters using perchlorate specialty resins, but the resin is poorly regenerated. Perchlorate was not easily removed from either nitrate …

General Coupon Collecting Models And Multinomial Games, James Y. Lee

UNLV Theses, Dissertations, Professional Papers, and Capstones

The coupon collection problem is one of the most studied problems in statistics. It is the problem of collecting r (r<∞) distinct coupons one by one from k different kinds (k<∞) of coupons. We note that this is equivalent to the classical occupancy problem which involves the random allocation of r distinct balls into k distinct cells. Although the problem was first introduced centuries ago, it is still actively investigated today. Perhaps its greatest feature is its versatility, numerous approaches, and countless variations. For this reason, we are particularly interested in creating a classification system for the many generalizations of the coupon collection problem. In this thesis, we will introduce models that will be able to categorize these generalizations. In addition, we calculate the waiting time for the models under consideration. Our approach is to use the Dirichlet Type II integral. We compare our calculations to the ones obtained through Monte Carlo simulation. Our results will show that our models and the method used to find the waiting times are ideal for solving problems of this type.

Assessment Of Impacts To Hydroclimatology And River Operations Due To Climate Change Over The Colorado River Basin, William Paul Miller

UNLV Theses, Dissertations, Professional Papers, and Capstones

This dissertation investigated the impacts of climate change to the hydroclimatology and river and reservoir management operations within the Colorado River Basin. Preliminary research indicated observed warming trends throughout the Colorado River Basin and corresponding seasonal trends to the magnitude and timing of runoff in the Colorado River Basin. Subsequent research investigated the changing character of precipitation and corresponding impacts to streamflow over the Colorado River Basin. Analysis of snowpack telemetry (SNOTEL) stations over the American West and Colorado River Basin indicated decreasing trends in annual snowpack, often at least at the 95% confidence interval. A shorter snowpack season was …

Bacillus Cereus And Bacillus Anthracis Germination Kinetics: A Michaelis-Menten Approach, Helen Luu

UNLV Theses, Dissertations, Professional Papers, and Capstones

Bacillus species are rod-shaped, gram-positive bacteria that are capable of producing endospores. In this dormant stage, the endospores can persist in hostile physical and chemical environments. Once conditions become favorable, the spores germinate into actively dividing cells, vegetative cells. Germination is a crucial step for the pathogenicity of the Bacilli in affecting a host organism.

Our study applies mathematical approaches to spore germination to determine whether the binding of one germinant will affect the binding of another germinant. We pursued this approach with two different species, B. cereus and B. anthracis, both pathogenic organisms. B. cereus is a widely known …

Transforming Space Into Place: Development, Rock Climbing, And Interpretation In Red Rock Canyon National Conservation Area, 1960-2010, Megan Sharp Weatherly

UNLV Theses, Dissertations, Professional Papers, and Capstones

Though Americans tend to view wilderness as separate from nature, environmental historians have argued that wilderness is a cultural construct more than a quantifiable geographic category. Red Rock Canyon National Conservation Area (NCA), a 195,000-acre tract located west of Las Vegas, Nevada, is one such cultural construction. Since 1960, this BLM-managed parcel has served as a local and regional expression of broader, national trends in outdoor recreation, interpretation, and development and thereby forced visitors to engage (often unknowingly) in a cultural dialogue about consumerism, technology, and identity. With information from newspapers, archival collections, oral histories, and government documents, this thesis …

Preparation And Characterization Of Extraction Chromatography Resins Using N-Donor Extractants For Trivalent Actinide And Lanthanide Separations, Christopher L. Klug

UNLV Theses, Dissertations, Professional Papers, and Capstones

Actinide and lanthanide elements exist in the geosphere and biosphere due to both natural abundances and anthropogenic activities. The investigation of the presence and transport of actinides through the environment is of great scientific interest. In order to prepare environmental samples for precise measurements, the individual actinides must be separated from the chemically similar lanthanides, and from neighboring actinides. Existing extraction chromatography resins are either poorly suited for this separation, have bleeding problems, are not reusable, or fail the CHON principle. In an effort to resolve these issues, malonamides and N-donor extractants from the BTP and BTBP classes of solvent …

Adaptive Management Of Complex Environmental Problems – Comparison Of National Nuclear Waste Management Policies, Carmel Letourneau

UNLV Theses, Dissertations, Professional Papers, and Capstones

Many of today's challenging environmental problems, to the point of manifesting themselves on a scale that has global, political consequences, likely result from long-term evolutionary developmental processes. The degree to which humans can manage the evolution of these problems remains an open question. Faced with such challenges, since the mid 1980s, an increasing number of scholars have developed other forms of management, in particular, adaptive management. Scholars suggest that improving the performance of adaptive management requires that environmental problems be understood as 'complex', open, evolving systems of interacting social and environmental subsystems. To date, narrative has been the primary approach …

Filtration And Growth Rate Of Lake Mead Quagga Mussels (Dreissena Bugensis) In Laboratory Studies And Analyses Of Bioaccumulation, Carolyn Louise Link

UNLV Theses, Dissertations, Professional Papers, and Capstones

In January of 2007, Quagga Mussels (Dreissena bugensis) were identified in Lake Mead, Nevada. An aquatic invasive species, these mussels can significantly alter ecosystems. This study sought to quantify three ecological traits of the species through a series of laboratory experiments and analyses, providing information both for comparison with Dreissena in other locations, as well as for limnologic management decisions. Filtration rate of quagga mussels was quantified using algal strains and natural seston. Two strains of green algae, Nannochloris and Scenedesmus were used to determine mussel filtration rates with a spectrophotometer. Quagga filtration rates of collected Lake Mead seston were …

Two-View Transductive Support Vector Machines, Guangxia Li, Steven C. H. Hoi, Kuiyu Chang

Research Collection School Of Computing and Information Systems

Obtaining high-quality and up-to-date labeled data can be difficult in many real-world machine learning applications, especially for Internet classification tasks like review spam detection, which changes at a very brisk pace. For some problems, there may exist multiple perspectives, so called views, of each data sample. For example, in text classification, the typical view contains a large number of raw content features such as term frequency, while a second view may contain a small but highly-informative number of domain specific features. We thus propose a novel two-view transductive SVM that takes advantage of both the abundant amount of unlabeled data …

Using Fluid Inclusions To Trace Formative Fluid Evolution At The Verde And Pancho Porphyry Au Deposits Of The Refugio District, Chile, Brian Joshua Aillaud

UNLV Theses, Dissertations, Professional Papers, and Capstones

Evolution of magmatically-derived formative fluids, and the processes that control the ratio of ore metals in porphyry and high-sulfidation epithermal deposits remain enigmatic. The Refugio district in the Maricunga Belt of Northern Chile hosts the temporally and spatially related Pancho and Verde porphyry gold deposits. Vein types at Pancho include A-veins, transitional veins, banded veins, D-veins and quartz-alunite ledges that formed by replacement. Verde East and West lack A-veins, and show an earliest vein type with transitional characteristics of A- to banded veins, banded veins and D-veins. Fluid inclusions and quartz textures were characterized by using optical microscopy and cathodoluminesence …

Earthy Bride, Melissa S. Foerster

UNLV Theses, Dissertations, Professional Papers, and Capstones

There are nearly 2.5 million couples getting married in the United States each year (Harrison, 2008, pg. xi). That breaks down to more than 6,300 weddings in a single day. The average wedding in the United States “produces 63 tones of CO2 and 400-600 pounds of trash” and therefore, newlyweds are creating over 3,500,000 pounds of trash in a single at their weddings (Harrison, 2009, ¶ 2)! The green movement is on the rise and wedding industry needs to implement it to meet new demands. In order to do people need to be informed of the importance, benefits and savings …