Physical Sciences and Mathematics Commons^™

Tolerance And Accumulation Of Copper, Lead And Zinc By Ceratopteris Richardii, Dorothy Jelagat Cheruiyot

Theses and Dissertations

Environmental contamination has increased rapidly in recent years. There is a need to develop cheap and environmentally friendly remediation methods. Numerous studies have evaluated the ability plants to remove contaminants from the environment. The present study evaluated the ability of Ceratopteris richardii gametophytes and sporophytes to tolerate copper, lead and zinc and for the sporophytes to accumulate the three metals in their shoots. Spores were sown in plant medium treated with varying concentrations of Cu, Pb and Zn. Fifteen-day- old sporophytes were transferred into medium mixed with varying concentrations of the three metals. Ceratopteris richardii tolerated and accumulated each of …

The Origin Of The 511 Kev Positron Annihilation Emission Morphology, Bethany Johns

All Theses

The 511 keV positron annhilation emission from the Galactic bulge has yet to solely be attributed to any astrophysical source of positrons. The 511 keV line, characteristic of electron-positron annihilation, was discovered in 1970 by Johnson and Haymes [1973] almost 40 years ago. Most recently the INTERnational Gamma-Ray Astrophysical Laboratory (INTEGRAL) [Knodlseder 1997] has measured the annihilation rates of both components of the Galaxy. The bulge and disk annihilation rates are (1.5 ± 0.1) x 10^43 e+ s^-1 and(0.3 ± 0.2) x 10^43 e+ s^-1, respectively. The ratio of the bulge rate to that of the disk ranges from 3-9. …

Explaining Inferences In Bayesian Networks, Ghim-Eng Yap, Ah-Hwee Tan, Hwee Hwa Pang

Research Collection School Of Computing and Information Systems

While Bayesian network (BN) can achieve accurate predictions even with erroneous or incomplete evidence, explaining the inferences remains a challenge. Existing approaches fall short because they do not exploit variable interactions and cannot account for compensations during inferences. This paper proposes the Explaining BN Inferences (EBI) procedure for explaining how variables interact to reach conclusions. EBI explains the value of a target node in terms of the influential nodes in the target's Markov blanket under specific contexts, where the Markov nodes include the target's parents, children, and the children's other parents. Working back from the target node, EBI shows the …

Innovation In The Programmable Web: Characterizing The Mashup Ecosystem, C. Jason Woodard, Shuli Yu

Research Collection School Of Computing and Information Systems

This paper investigates the structure and dynamics of the Web 2.0 software ecosystem by analyzing empirical data on web service APIs and mashups. Using network analysis tools to visualize the growth of the ecosystem from December 2005 to 2007, we find that the APIs are organized into three tiers, and that mashups are often formed by combining APIs across tiers. Plotting the cumulative distribution of mashups to APIs reveals a power-law relationship, although the tail is short compared to previously reported distributions of book and movie sales. While this finding highlights the dominant role played by the most popular APIs …

Robust Regularized Kernel Regression, Jianke Zhu, Steven C. H. Hoi, Michael R. Lyu

Research Collection School Of Computing and Information Systems

Robust regression techniques are critical to fitting data with noise in real-world applications. Most previous work of robust kernel regression is usually formulated into a dual form, which is then solved by some quadratic program solver consequently. In this correspondence, we propose a new formulation for robust regularized kernel regression under the theoretical framework of regularization networks and then tackle the optimization problem directly in the primal. We show that the primal and dual approaches are equivalent to achieving similar regression performance, but the primal formulation is more efficient and easier to be implemented than the dual one. Different from …

Scaling Up Multi-Agent Reinforcement Learning In Complex Domains, Dan Xiao, Ah-Hwee Tan

Research Collection School Of Computing and Information Systems

TD-FALCON (Temporal Difference - Fusion Architecture for Learning, COgnition, and Navigation) is a class of self-organizing neural networks that incorporates Temporal Difference (TD) methods for real-time reinforcement learning. In this paper, we present two strategies, i.e. policy sharing and neighboring-agent mechanism, to further improve the learning efficiency of TD-FALCON in complex multi-agent domains. Through experiments on a traffic control problem domain and the herding task, we demonstrate that those strategies enable TD-FALCON to remain functional and adaptable in complex multi-agent domains

Heats Of Solvation Of Organic Liquids In Room Temperature Ionic Liquids, Paula Jeanette Beach

Masters Theses

Ionic liquids are of potential use in industry as reusable, non-polluting solvents. Their thermochemical properties need to be known to facilitate planning of processes and experiments using these solvents. Two ionic liquids: 1-Butyl-3-methylimidazolium hexafluorophosphate ([C4mim]PF6 or [bmim]PF6) and 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([hmim]NTf2) were studied using a calorimeter. Various organic liquids were introduced into the solvents and their heats of solution were measured and tabulated. Potential effects of certain functional groups such as alcohol, amine, carboxylic acid, ketone, and aldehyde were examined as well as aromatics versus chains and saturated rings.

Experimental Determination Of Emissivity And Resistivity Of Yttria Stabilized Zirconia At High Temperatures, Howard Mosley Frederick

Masters Theses

The emissivity and resistivity of yttria stabilized zirconia (YsZ), Y₂O₃-ZrO₂, a ceramic material that has been specially fabricated for use as an electrically powered high temperature air heater are determined for temperatures above 2000 K. Published results of measurements of emissivity and resistivity of yttria, zirconia, and their alloys at temperatures above 2000 K are rare in the technical literature. A survey of literature describing the properties of YsZ, particularly literature concerning the ionic conduction process at high temperatures, is assembled to provide a theoretical basis for the formulation of a temperature and resistivity …

The Use Of Lanthanide Triflates As A Method For Reducing Ytterbium(Iii) To Ytterbium(Ii), Latasha Michelle Garrett

Masters Theses

High purity lutetium (99.999%) is employed in the manufacture of cerium-doped lutetium oxyorthosilicate. Such lutetium is in high demand because the cerium-doped lutetium oxyorthosilicate is the best gamma-detecting scintillator known. Solvent extraction is the most widely used method for separating the rare earths on an industrial scale at 99.999% purity. However, this process is time consuming and requires 80-100 separation stages. The major difficulty in pure lutetium production is the separation from the adjacent element, ytterbium. If ytterbium(III) could be reduced to ytterbium(II), this would permit a different chemistry between ytterbium(II) and the trivalent state elements, allowing a more facile …

A Note On Hamel Bases, Jeremy S. Higdon

Masters Theses

The purpose of this paper is to discuss certain properties of Hamel bases. In particular, we reprove and generalize a theorem of R. Mabry (Aequations Mathematicae 71 (2006) p. 294-299) on the non-existence of nontrivial Hamel bases closed under multiplication.

The Evaluation Of A Chemical Fingerprinting Technique For Identifying The Sources Of In-Stream Sediments, Robert Alexander Hull

Masters Theses

Sediment is often listed as one of the main contributors to the impairment of surface waters throughout the United States. Sediment source identification is difficult in watersheds with complex combinations of land-uses and non-point sources because of the complexities involved in correlating water quality data, which are relatively easy to collect, to the source of a degrading component. The elemental properties of a particular soil on the landscape may be viewed as a “fingerprint”. A comparison of the elemental fingerprints of potential sources and in-stream sediment may be used to establish sediment source. The objectives of this investigation were to …

Environmental Analysis And White Cell Applications Ftir Spectroscopy, Maria Gabriela Oliveros

Masters Theses

The research is concerned with atmospheric chemistry & physics, and analyzing the environment with respect to the quantity of molecules is in the air we breathe. Fourier Transform Infrared Spectroscopy is used to identify the IR active molecules in our atmosphere. FTIR Spectrometer determines the intensity loss for molecules that have absorbed IR light. The FTIR spectroscopy is performed using the light from the sun or a carbon rod light source in the lab. A Sun-tracking device was employed to direct the sunlight into the spectrometer. Open-path measurements were made using multiple mirror reflections of the carbon rod light source …

The Adsorption Of 2-Ketogluconate By Goethite, Jessica Suzanne Journey

Masters Theses

The low-molecular-mass-organic acid, 2-ketogluconate (kG), has been found to exist in significant concentrations in the rhizosphere of agricultural soils. Adsorption of kG by constant potential mineral surfaces may influence soil chemical processes. This study examines influence of temperature, pH, and ionic environment on the adsorption of kG by goethite. When kG was present on the surface of goethite, the pH_pzc decreased by approximately 0.4 pH units, from pH 7.6 to pH 7.2, suggesting that kG is chemisorbed to the goethite surface via ligand exchange mechanisms. The adsorption of kG by goethite is a function of pH and ionic strength. …

Optimal Control Of Epidemic Models Involving Rabies And West Nile Viruses, Timothy Joseph Clayton

Doctoral Dissertations

This research considers the application of Optimal Control theory to minimize the spread of viral infections in disease models. The population models under consideration are systems of ordinary differential equations and represent epidemics arising due to either rabies or West Nile virus. Optimal control strategies are analyzed using Pontryagin’s Maximum Principle and illustrated based upon computer simulations.

The first model describes a population of raccoons and its interaction with the rabies virus, thus dividing the animals into four classes: susceptible, exposed, immune, and recovered (SEIR). The model includes a birth pulse during the spring of the year and …

Biochemical Reactions Instigating Vision – Parameter Sensitivity Analysis, Sophonie Ketcha Tchoua

Masters Theses

The purpose of this work is to investigate the sensitivity of parameters involved in a cascade of biochemical reactions occurring in photoreceptor cells in the retina of the eye. This cascade constitutes the first stage of the elaborate process of vision, by which light captured in a photoreceptor generates an electrical signal. It is this signal that travels to the brain enabling vision.

Sensitivity on parameters was performed on an ODE model of the biochemical cascade using two methods. One method used SimLab, a statistical sensitivity analysis program. We found that there are at most five important parameters out of …

Road To The Green Seal, Milos Cerovic

UNLV Theses, Dissertations, Professional Papers, and Capstones

Green Seal is one of the most recognized non profit organizations that work closely with companies from all over the country to provide certification of environmentally friendly products used by employees. There are many reasons for product certification process. The most obvious one is to preserve the environment and energy efficiency. Another important reason is to reduce the cost and increase the profit by using products with higher durability and less expensive packaging. Of equal importance is participation in green initiatives which allows hotels and other organizations to capture additional businesses, media exposure etc. InterContinental Chicago is the largest and …

Surface Water Interaction With The Flood Plain In The Lower Virgin River, Clark County, Nevada, Jeffrie L. Pompeo

UNLV Theses, Dissertations, Professional Papers, and Capstones

Development of existing surface water rights on the Virgin River would decrease Southern Nevada's dependency on the Colorado River. Three monitoring sites were established to examine the relationship between Virgin River surface water flows and the floodplain aquifer. Automated water level measuring devices were installed in piezometers and wells to continuously track water levels and flow direction. Pump tests were conducted to establish the hydraulic parameters of the floodplain aquifer. Water chemistry data was analyzed to help determine the correlation between the floodplain aquifer and Virgin River water. Precipitation, recharge, streamflow and ET estimates were used to discuss water budgets. …

Group-Aware Stream Filtering For Bandwidth-Efficient Data Dissemination, Ming Li, David Kotz

Dartmouth Scholarship

In this paper we are concerned with disseminating high-volume data streams to many simultaneous applications over a low-bandwidth wireless mesh network. For bandwidth efficiency, we propose a group-aware stream filtering approach, used in conjunction with multicasting, that exploits two overlooked, yet important, properties of these applications: 1) many applications can tolerate some degree of “slack” in their data quality requirements, and 2) there may exist multiple subsets of the source data satisfying the quality needs of an application. We can thus choose the “best alternative” subset for each application to maximize the data overlap within the group to best benefit …

Are Cattle Die-Offs Predictable On The Borana Plateau, D. Layne Coppock, Getachew Gebru, Solomon Desta, Sintayehu Mesele, Seyoum Tezerra

Environment and Society Faculty Publications

Drought regularly affects rangelands and contributes to high death rates for livestock and poverty for pastoralists. But do livestock losses occur randomly simply when rainfall is low, or are they cyclical and predictable? Previously, PARIMA researchers proposed that high stocking rates—combined with low rainfall—trigger livestock die-offs on the Borana Plateau. It takes about six years for animal numbers to recover, setting the stage for another die-off when a dry year occurs. This “boom-and-bust” cycle is based on observed herd crashes in 1983-5, 1991-3, and 1998-9. Researchers predicted in 2002 that the next major die-off would occur during 2004-06, and one …

What Are Consumers In Moyale, Kenya Willing To Pay For Improved Milk Quality?, D. Layne Coppock, Francis O. Wayua, Mohamed G. Shibia, Moses S. Mamo

Environment and Society Faculty Publications

Pastoralists in northern Kenya and southern Ethiopia may be able to diversify income by selling milk to urban residents. However, milk sold in open-air markets is often low in quality because it has been transported long distances without refrigeration and is subject to spoilage, or because milk is adulterated prior to sale to boost volume or enhance appearance. Open-air markets are characterized by low-income consumers who must make choices about milk quality with virtually no information other than their own sensory perceptions. PARIMA researchers used an experimental-auction approach to determine what residents in Moyale, Kenya, are willing to pay (WTP) …

The Möbius Geometry Of Hypersurfaces, Michael Bolt

University Faculty Publications and Creative Works

No abstract provided.

A Mobile Agent-Supported Web Services Testing Platform, Jia Zhang, Di Xu

Jia Zhang

No abstract provided.

An Aztec 1.1 Mm Survey Of The Goods-N Field – I. Maps, Catalogue And Source Statistics, Thushara Perera, E. Chapin, J. Austermann, K. Scott, G. Wilson, M. Halern, A. Pope, D. Scott, M. Yun, J. Lowenthal, G. Morrison, I. Aretxaga, J. Bock, K. Coppin, M. Crowe, L. Frey, D. Hughes, Y. Kang, S. Kim, P. Mauskopf

Thushara A. Perera

No abstract provided.

Towards Self-Organizing, Smart Business Networks: Let’S Create ‘Life’ From Inert Information, David Bray, Benn Konsynski

David A. Bray

We review three different theories that can inform how researchers can determine the performance of smart business networks, to include: (1) the Theory of Evolution, (2) the Knowledge-Based Theory of the Firm, and (3) research insights into computers and cognition. We suggest that each of these theories demonstrate that to be generally perceived as smart, an organism needs to be self-organizing, communicative, and tool-making. Consequentially, to determine the performance of a smart business network, we suggest that researchers need to determine the degree to which it is self-organizing, communicative, and tool-making. We then relate these findings to the Internet and …

Fluoranthene, But Not Benzo[A]Pyrene, Interacts With Hypoxia Resulting In Pericardial Effusion And Lordosis In Developing Zebrafish, Cole W. Matson, Alicia R. Timme-Laragy, Richard T. Di Giulio

Alicia R. Timme-Laragy

Previous research has documented several PAHs that interact synergistically, causing severe teratogenicity in developing fish embryos. The coexposure of CYP1A inhibitors (e.g. FL or ANF) with AHR agonists (e.g. BaP or BNF) results in a synergistic increase in toxicity. As with chemical CYP1A inhibitors, it has also been shown that CYP1A morpholinos exacerbate BNF-induced embryotoxicity. We hypothesized that a hypoxia-induced reduction in CYP1A activity in BNF or BaP-exposed zebrafish embryos would similarly enhance pericardial effusion and other developmental abnormalities. BaP, BNF, ANF, and FL exposures, both individually and as BaP+FL or BNF+ANF combinations, were performed under hypoxia and normoxia. CYP1A …

International Terrorism:Role ,Responsibility And Operation Of Media Channles, Ratnesh Dwivedi Mr

Ratnesh Dwivedi

"Terrorism" is a term that cannot be given a stable defintion. Or rather, it can, but to do so forstalls any attempt to examine the major feature of its relation to television in the contemporary world. As the central public arena for organising ways of picturing and talking about social and political life, TV plays a pivotal role in the contest between competing defintions, accounts and explanations of terrorism. Which term is used in any particular context is inextricably tied to judgemements about the legitimacy of the action in question and of the political system against which it is directed. …

Tuning Nonlinear Optical Properties In Π-Delocalizable Ruthenium Complexes, T. Christopher Corkery, Sanjay S. Chavan, Marie P. Cifuentes, Marek Samoc, Stijn Van Cleuvenbergen, Inge Asselberghs, Koen Clays, Mark G. Humphrey

Chris Corkery

No abstract provided.

The Star Formation Law In Nearby Galaxies On Sub-Kpc Scales, F. Bigiel, A. Leroy, F. Walter, E. Brinks, W.J.G. De Blok, B. F. Madore, Michele D. Thornley

Michele Thornley

Do The Coefficients Of A Modular Form Really "Encode Arithmetic Data"?, Ken Mcmurdy, Hari Ravindran

Mathematical Sciences Technical Reports (MSTR)

Language and terminology are so critical to the understanding of modern math- ematics that it is often difficult for even very good mathematicians from different fields to discuss their work in any detail. As a result, common phrases often evolve within each discipline which attempt to capture the avor of some impor- tant idea while avoiding technicality and jargon. For example, when algebraic number theorists are asked why they are so interested in modular forms, it has become common to say with enthusiasm that the coefficients of a modular form "encode arithmetic data". If pressed further, one might go on …

Real-Time Automatic Price Prediction For Ebay Online Trading, Ilya Igorevitch Raykhel

Theses and Dissertations

While Machine Learning is one of the most popular research areas in Computer Science, there are still only a few deployed applications intended for use by the general public. We have developed an exemplary application that can be directly applied to eBay trading. Our system predicts how much an item would sell for on eBay based on that item's attributes. We ran our experiments on the eBay laptop category, with prior trades used as training data. The system implements a feature-weighted k-Nearest Neighbor algorithm, using genetic algorithms to determine feature weights. Our results demonstrate an average prediction error of 16%; …