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 …

Current Status And Long-Term Trends In Water Quality And Living Resources In The Virginia Tributaries And Chesapeake Bay Mainstem From 1985 Through 2007, Daniel M. Dauer, Harold G. Marshal, John R. Donat, Michael F. Lane, Suzanne C. Doughten, Frederick A. Hoffman

Status and Trends for Virginia Chesapeake Bay

The period prior to the implementation of the Chesapeake Bay Monitoring Program was characterized by a marked decline in the water quality of the Chesapeake Bay. The disappearance of submerged aquatic vegetation in certain regions of the Bay, declines in the abundance of some commercially and recreationally important species, increases in the incidence of low dissolved oxygen events, changes in the Bay's food web, and other ecological problems were related to deteriorating water quality (e.g. USEPA, 1982,1983;Officer et al.,1984; Orth and Moore, 1984). The results of concentrated research efforts in the late 1970s and early 1980s stimulated the establishment of …

The Equivariant Chow Rings Of Quot Schemes, T. Braden, Linda Chen, F. Sottile

Mathematics & Statistics Faculty Works

We give a presentation for the (integral) torus-equivariant Chow ring of the quot scheme, a smooth compactification of the space of rational curves of degree d in the Grassmannian. For this presentation, we refine Evain's extension of the method of Goresky, Kottwitz, and MacPherson to express the torus-equivariant Chow ring in terms of the torus-fixed points and explicit relations coming from the geometry of families of torus-invariant curves. As part of this calculation, we give a complete description of the torus-invariant curves on the quot scheme and show that each family is a product of projective spaces.

Calculations Of K-Shell Fluorescence Yields And Photoabsorption Cross Sections For Carbon Ions At The K-Edge, Muhammet Fatih Hasoglu

Dissertations

The advent of new space missions providing high-precision observations has engendered the need for reliable and precise K-shell atomic data in order to interpret these X-ray spectra. In response to this need, we focused on the calculation of K-shell fluorescence yields for 2 nd -row ions. A secondary project was undertaken in order to treat theoretically the K-shell X-ray absorption processes in carbon ions. These calculated fluorescence yields of 2nd -row ions and theX-ray photoabsorption cross sections of carbon are astrophysically important in determining (1) charge-changing probabilities, such as Auger vs. radiative decay, and (2) chemical abundances of the interstellar …

Evaluation Of Electron Donor Materials Used To Create Subsurface Permeable Reactive Barriers For Enhanced Reductive Dechlorination Of Chlorinated Ethenes, Elizabeth S. Semkiw

Dissertations

Chlorinated ethenes (CEs) are widespread ground water contaminants, apparently due to their extensive migration from numerous contamination source points. In this study, a long-term field investigation and aquifer microcosm experiments were combined to evaluate the effectiveness of electron donor materials used to create and maintain subsurface permeable reactive barriers (PRBs) for the enhanced in-situ biodegradation of CEs. The laboratory component includes the first side-by-side comparison of electron donor materials dairy whey, lactate syrup, and Hydrogen Release Compound® (HRC), in which dechlorination rates, fermentation product distributions, and H₂ production were monitored as measures of substrate efficiency. Field study allowed the …

Switch On And Switch Off Nanosensors For The Detection Of Nerve Gas Agents, Shankar Varaganti

Dissertations

The central hypothesis of this research is the development of novel nanosensors by a bottom-up approach for the detection of nerve gas agents. The nanosensor assembly consists of four main parts; nanoparticles (N), Monomer (M), Complex (C) and Receptor (R). Two novel Ru (II)-bipyridyl and zinc complexes with tryptophan receptors either in 4,4' or 5,5' position of the bipyridyl ring have been synthesized and characterized by using ¹H NMR, ¹³C NMR, mass spectrometry and absorption spectroscopy. Silica nanoparticles or quantum dots are used as a platform for the nanosensors. Highly conjugated stilbene type compounds are used as monomers. …

Remarks On The Stability Of Some Size-Structured Population Models Iii: The Case Of Constant Inflow Of Newborns, Mohammed El-Doma

Applications and Applied Mathematics: An International Journal (AAM)

The stability of some size-structured population dynamics models are investigated. We determine the steady states and study their stability. We also give examples that illustrate the stability results. The results in this paper generalize previous results, for example, see Calsina, et al. (2003), El- Doma (2006) and El-Doma (2008).

Link Rate Allocation Under Bandwidth And Energy Constraints In Sensor Networks, Maggie Cheng, Xuan Gong, Lin Cai

Computer Science Faculty Research & Creative Works

In sensor networks, both energy and band width are scarce resources. in the past, the energy efficient routing problem has been vastly studied in order to maximize network lifetime, but link bandwidth has been optimistically assumed to be abundant. as energy con straint affects how data should be routed, link bandwidth also affects not just the routing topology but also the allowed data rate on each link, which in turn affects lifetime. Previous works that focus on energy efficient operations in sensor networks with the sole objective of maximizing network lifetime only consider the energy constraint and ignore the bandwidth …

Pas: Predicate-Based Authentication Services Against Powerful Passive Adversaries, Sriram Chellappan, Xiaole Bai, Wenjun Gu, Xun Wang, Dong Xuan, Bin Ma

Computer Science Faculty Research & Creative Works

Securely authenticating a human user without assistance from any auxiliary device in the presence of powerful passive adversaries is an important and challenging problem. Passive adversaries are those that can passively monitor, intercept, and analyze every part of the authentication procedure, except for an initial secret shared between the user and the server. In this paper, we propose a new secure authentication scheme called predicate-based authentication service (PAS). In this scheme, for the first time, the concept of a predicate is introduced for authentication. We conduct analysis on the proposed scheme and implement its prototype system. Our analytical data and …

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 …

Planning With Ifalcon: Towards A Neural-Network-Based Bdi Agent Architecture, Budhitama Subagdja, Ah-Hwee Tan

Research Collection School Of Computing and Information Systems

This paper presents iFALCON, a model of BDI (beliefdesire-intention) agents that is fully realized as a selforganizing neural network architecture. Based on multichannel network model called fusion ART, iFALCON is developed to bridge the gap between a self-organizing neural network that autonomously adapts its knowledge and the BDI agent model that follows explicit descriptions. Novel techniques called gradient encoding are introduced for representing sequences and hierarchical structures to realize plans and the intention structure. This paper shows that a simplified plan representation can be encoded as weighted connections in the neural network through a process of supervised learning. A case …

Solving Higher Dimensional Initial Boundary Value Problems By Variational Iteration Decomposition Method, Muhammad A. Noor, Syed T. Mohyud-Din

Applications and Applied Mathematics: An International Journal (AAM)

In this paper, we apply a relatively new technique which is called the variational iteration decomposition method (VIDM) by combining the traditional variational iteration and the decomposition methods for solving higher dimensional initial boundary value problems. The proposed method is an elegant combination of variational iteration and the decomposition methods. The analytical results of the problems have been obtained in terms of convergent series with easily computable components. The method is quite efficient and is practically well suited for use in these problems. Several examples are given to verify the accuracy and efficiency of the proposed technique.

Alagnak Wild River Visitor Use Project: Alagnak Wild River Resident User Study, Douglas Deur

Anthropology Faculty Publications and Presentations

This report represents a thematic summary of findings from the Alagnak Wild River Resident Users Study, the final project in a larger series of studies conducted for the National Park Service (NPS) as part of the Alagnak Wild River Visitor Use Project. The National Park service administers the 56 miles of designated Wild River along the Alagnak in collaboration with the Alaska Department of Fish and Game, which manages fish and wildlife populations along the river. The NPS is charged with managing the river’s natural and cultural resources, as well as preserving the river’s lands and resources for current and …

The Effect Of The Amide Substituent On The Biodistribution And Tolerance Of Lanthanide(Iii) Dota-Tetraamide Derivatives, Mark Woods, Peter Caravan, Carlos F.G.C. Geraldes, Matthew T. Greenfield, Garry Kiefer, Mai Lin, Kenneth Mcmillan, M. Isabel M. Prata, Ana C. Santos, Xiankai Sun, Jufeng Wang, Shanrong Zhang, Piyu Zhao, A. Dean Sherry

Chemistry Faculty Publications and Presentations

Objectives—Recent advances in the design of MRI contrast agents have rendered the lanthanide complexes of DOTA-tetraamide ligands of considerable interest, both as responsive MR agents and paramagnetic chemical exchange saturation transfer agents. The potential utility of these complexes for in vivo applications is contingent upon them being well tolerated by the body. The purpose of this study was to examine how the nature of the amide substituent, and in particular its charge, affected the fate of these chelates postinjection.

Materials and Methods—Complexes of 6 DOTA-tetraamide ligands were prepared in which the nature of the amide substituent was systematically …

The Distribution And Reproductive Success Of The Western Snowy Plover Along The Oregon Coast - 2008, David J. Lauten, Kathleen J. Castelein, David C. Bailey, Travis Lewis, Eleanor P. Gaines

Institute for Natural Resources Publications

From 1 April – 24 September 2008, we monitored the distribution, abundance and productivity of the federally Threatened Western Snowy Plover (Charadrius alexandrinus nivosus) along the Oregon coast. From north to south, we surveyed and monitored plover activity at Sutton Beach, Siltcoos River estuary, the Dunes Overlook, North Tahkenitch Creek, Tenmile Creek, Coos Bay North Spit, Bandon Beach, and New River. Our objectives for the Oregon coastal population in 2008 were to: 1) estimate the size of the adult Snowy Plover population, 2) locate plover nests, 3) continue selected use of miniexclosures (MEs) to protect nests from predators …

Anomalies In Electrostatic Calibrations For The Measurement Of The Casimir Force In A Sphere-Plane Geometry, W. J. Kim, M. Brown-Hayes, D. A.R. Dalvit, J. H. Brownell, R. Onofrio

Dartmouth Scholarship

We have performed precision electrostatic calibrations in the sphere-plane geometry, and observed anomalous behavior. Namely, the scaling exponent of the electrostatic signal with distance was found to be smaller than expected on the basis of the pure Coulombian contribution, and the residual potential found to be distance dependent. We argue that these findings affect the accuracy of the electrostatic calibrations and invite reanalysis of previous determinations of the Casimir force.

Metallicity Analysis Of Macho Galactic Bulge Rr0 Lyrae Stars From Their Light Curves, Andrea Kunder, Brian Chaboyer

Dartmouth Scholarship

We present metallicities of 2690 RR0 Lyrae stars observed toward the MACHO Survey fields in the Galactic bulge. These [Fe/H] values are based upon an empirically-calibrated relationship that uses the Fourier coefficients of the light curve and are accurate to ±0.2 dex. The majority of the RR0 Lyrae stars in our sample are located in the Galactic bulge, but 255 RR0 stars are associated with the Sagittarius (Sgr) dwarf galaxy. We find that the RR0 Lyrae stars that belong to the Galactic bulge have average metallicities [Fe/H] = -1.25, with a broad metallicity range from [Fe/H] = -2.26 to -0.15. …

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 …

Photopolymerization And Characterization Of Thiol-Enes And Thiourethanes, Qin Li

Dissertations

Compared to conventional acrylic monomer systems, thiol-ene photopolymerization, an efficient click process leading to the formation of dense and uniform molecular networks, has several distinct advantages including relative insensitivity to oxygen inhibition, high monomer conversion and low shrinkage. Although there has been a revival of interest in thiol-enes in the past 6 years, the structure-property relationship of these networks has not been explored in detail. For future applications, thiol-enes with higher shelf-life stability and glass transition temperatures need to be used. Sulfur containing urethanes, thiourethanes and dithiourethanes are a class of widely used materials due to their distinct properties such …

The Relationship Betweeen Dynamic And Chemical Factors On The Morphology In Aot-Water-Polymer Systems, Jolanta Elzbieta Marszalek

Dissertations

Photopolymerization of reverse microemulsion demonstrates strong influences from dynamical and chemical factors on morphology of formed polymer systems. Upon polymerization the clear microemulsion with nanoscale structures transforms into opaque films with larger aggregates that scatter light. Studied here were microemulsions based on acrylate and on thiol-ene chemistries. The difference in the two reaction mechanisms results in the phase separation occurring at different stages of the material formation. Consequently, the morphology of the material demonstrates distinct dissimilarities in the two systems. In addition, the chemical structure of the monomers promotes these morphological differences. When the microemulsion is composed of acrylate and …

From The Editor, Susan Fingerman

Sci-Tech News

No abstract provided.

Sla 2008 Session Report

Sci-Tech News

No abstract provided.

On The Cover

Sci-Tech News

No abstract provided.

Aerospace Section, Kathryn Breininger

Sci-Tech News

No abstract provided.

Beyond The Chemistry Web, Bob Buchanan

Sci-Tech News

No abstract provided.

Web Reviews, Lisa R. Johnston

Sci-Tech News

No abstract provided.

New Science And Technology Journals, Earl Mounts

Sci-Tech News

No abstract provided.

Science-Technology Division, Christine Whitaker

Sci-Tech News

No abstract provided.

Full Issue: Vol. 62, No. 4

Sci-Tech News

No abstract provided.

Ambiguous Optimistic Fair Exchange, Qiong Huang, Guomin Yang, Duncan S. Wong, Willy Susilo

Research Collection School Of Computing and Information Systems

Optimistic fair exchange (OFE) is a protocol for solving the problem of exchanging items or services in a fair manner between two parties, a signer and a verifier, with the help of an arbitrator which is called in only when a dispute happens between the two parties. In almost all the previous work on OFE, after obtaining a partial signature from the signer, the verifier can present it to others and show that the signer has indeed committed itself to something corresponding to the partial signature even prior to the completion of the transaction. In some scenarios, this capability given …