Physical Sciences and Mathematics Commons^™

The Standardized Fish Bioassay Procedure For Detecting And Culturing Actively Toxic Pfiesteria, Used By Two Reference Laboratories For Atlantic And Gulf Coast States, Joann M. Burkholder, Harold G. Marshall, David W. Seaborn, Nora J. Deamer-Melia

Biological Sciences Faculty Publications

In the absence of purified standards of toxins from Pfiesteria species, appropriately conducted fish bioassays are the "gold standard" that must be used to detect toxic strains of Pfiesteria slop. from natural estuarine water or sediment samples and to culture actively toxic Pfiesteria. In this article, we describe the standardized steps of our fish bioassay as an abbreviated term for a procedure that includes two sets of trials with fish, following the Henle-Koch postulates modified for toxic rather than infectious agents. This procedure was developed in 1991, and has been refined over more than 12 years of experience in …

Jointly Coordinating Ecn And Tcp For Rapid Adaptation To Varying Bandwidth, Archan Misra, Teunis Ott

Research Collection School Of Computing and Information Systems

The introduction of service differentiation in the Internet implies that the residual bandwidth available to best-effort traffic becomes highly variable. We explore the design of a rapidly-reactive congestion control framework, where the ECN-aware best-effort flows aggressively go after any unused capacity. By making routers mark packets in a much more aggressive manner, we are able to achieve fast backoff in the network without resorting to the TCP's current drastic step of halving the congestion window. Simulations indicate that our ECN-mod protocol is better than ECN-NewReno in exploiting rapid variations in the available bandwidth. Moreover, the milder backoff policy of ECN-mod …

Mining Multi-Level Rules With Recurrent Items Using Fp'-Tree, Kok-Leong Ong, Wee-Keong Ng, Ee Peng Lim

Research Collection School Of Computing and Information Systems

Association rule mining has received broad research in the academic and wide application in the real world. As a result, many variations exist and one such variant is the mining of multi-level rules. The mining of multi-level rules has proved to be useful in discovering important knowledge that conventional algorithms such as Apriori, SETM, DIC etc., miss. However, existing techniques for mining multi-level rules have failed to take into account the recurrence relationship that can occur in a transaction during the translation of an atomic item to a higher level representation. As a result, rules containing recurrent items go unnoticed. …

A Review Of Data Mining Techniques, Sang Jun Lee, Keng Siau

Research Collection School Of Computing and Information Systems

Terabytes of data are generated everyday in many organizations. To extract hidden predictive information from large volumes of data, data mining (DM) techniques are needed. Organizations are starting to realize the importance of data mining in their strategic planning and successful application of DM techniques can be an enormous payoff for the organizations. This paper discusses the requirements and challenges of DM, and describes major DM techniques such as statistics, artificial intelligence, decision tree approach, genetic algorithm, and visualization.

Integrating Color And Spatial Features For Content-Based Video Retrieval, Tong Lin, Chong-Wah Ngo, Hong-Jiang Zhang, Qing-Yun Shi

Research Collection School Of Computing and Information Systems

In this paper, we present a novel and efficient scheme for extracting, indexing and retrieving color images. Our motivation was to reduce the space overhead of partition-based approaches taking advantage of the fact that only a relatively low number of distinct values of a particular visual feature is present in most images. To extract color feature and build indices into our image database we take into consideration factors such as human color perception and perceptual range, and the image is partitioned into a set of regions by using a simple classifying scheme. The compact color feature vector and the spatial …

Hierarchical Mobility Management For Voip Traffic, Archan Misra, Subir Das, Anthony J. Mcauley

Research Collection School Of Computing and Information Systems

A hierarchical IP-based mobility management mechanism is proposed for VoIP applications. The suggested mechanism uses the DMA (dynamic mobility agent) architecture, based on IDMP (intra-domain mobility management protocol), for managing intra-domain mobility and the dynamic binding mechanism of SIP (session initiation protocol) for managing global mobility. This combination of network and application layer mobility management reduces the global signaling load, provides fast handoff for ongoing conversations, enables efficient global transport and supports IP-layer paging.

Rancho West Estates Water Distribution System Replacement Funding Project, Sherry Evans-Carmichael

Water Resources Professional Project Reports

The Rancho West Mobile Home Association (RWMHA or Association) needed funding to replace the aging Rancho West Estates (RWE) water distribution system to ensure a dependable future water supply, in terms of quality and quantity, for association members and residents of the RWE. The RWMHA did not qualify for commercial loans and did not have enough money to pay for the project. Association Board members stated working to obtain finding to replace the water distribution system in 1996. RWMHA Board members were very concerned about the health and welfare of all members and residents of the RWE. Concerns that were …

Microbially Mediated Reduction And Immobilization Of U(Vi) In Groundwater At A Site In Konigstein, Germany, Danielle D. Diehl

Water Resources Professional Project Reports

Groundwater supplies are increasingly threatened by organic, inorganic and radioactive contaminants introduced to the environment by improper disposal or accidental release. WISMUT, a German government owned company conducted in situ acid leach mining for decades to extract uranium from a mine at Konigstein. The uranium mine is currently undergoing remediation. The first objective of this research is to determine whether dissolved U(VI) can be precipitated via microbially mediated reduction to its insoluble form.

An Object-Oriented Resource Pool Model In Support Of Discrete Event Simulations, Srinivas Gullapalli

Electrical & Computer Engineering Theses & Dissertations

The proper distribution of resources is a key factor in simulation. Resources provide the supporting facilities, equipment, and personnel for carrying out activities. The number of resources has a direct impact on the overall effectiveness of the simulation as it does in real life. If the number is insufficient, it generally takes more time for the process to complete. On the other hand, if the number is too high, the cost incurred on the resources will be unnecessarily large. Therefore, the count should be a compromise between the two extremes.

In this thesis, an attempt is made to generalize the …

Effects Of Trapping And Subsequent Short-Term Confinement Stress On Plasma Corticosterone In The Brown Treesnake (Boiga Irregularis) On Guam, Tom Mathies, Todd A. Felix, Valentine A. Lance

United States Department of Agriculture Wildlife Services: Staff Publications

The effects of capture in a live trap and subsequent handling stress on plasma concentrations of corticosterone and other sex steroids were examined in wild male and female brown treesnakes (Boiga irregularis), an introduced species on Guam that has been implicated in the extirpation or decline of many of that island's vertebrate species. Males and females that spent 1 night in a trap had plasma levels of corticosterone about four and two times higher, respectively, than those of the respective free-ranging controls. Mean plasma levels of corticosterone of snakes that had spent 3 nights in a trap were …

Decline Of The Red-Winged Blackbird Population In Ohio Correlated To Changes In Agriculture (1965-1996), Bradley F. Blackwell, Richard A. Dolbeer

United States Department of Agriculture Wildlife Services: Staff Publications

Based on North American Breeding Bird Survey (BBS) data since 1966, Ohio has traditionally hosted 1 of the highest breeding season densities of red-winged blackbirds (Agelaius phoeniceus) of any U.S. state or Canadian province. However, from 1966 through 1996, breeding populations of red-winged blackbirds in Ohio showed a marked decline (x̅ % change/yr in birds per route = -3.9), with breeding population indices decreasing by over 53%. Because the red-winged blackbird successfully adapted to habitats created by agricultural expansion over the last century and became a recognized pest of crops such as corn (Zea mays), …

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 …

Domain State Susceptibility In Fecl2/Copt-Heterostructures, Christian Binek

Christian Binek Publications

Magnetic heterostructures with perpendicular anisotropy consisting of antiferromagnetic (111)-oriented FeCl2 single crystals and thin ferromagnetic CoPt-multilayers are investigated by ac-susceptometry after cooling in various axial magnetic fields to below the Néel temperature. The freezing process drives the system into a metastable antiferromagnetic domain state which gives rise to a huge excess contribution to the complex parallel susceptibility on heating in zero magnetic field. Its glow curve-like temperature dependence is modeled within the framework of a simple analytical approach. It involves the susceptibility of thermally activated clusters originating from antiferromagnetic stacking faults as well as the contribution of pairs of antiparallel …

Relationships Between Synoptic-Scale Transport And Interannual Variability Of Inorganic Cations In Surface Snow At Summit, Greenland: 1992-1996, J F. Slater, Jack E. Dibb, Barry D. Keim, D W. Kahl

Earth Sciences

To fully utilize the long-term chemical records retrieved from central Greenland ice cores, specific relationships between atmospheric circulation and the variability of chemical species in the records need to be better understood. This research examines associations between the variability of surface snow inorganic cation chemistry at Summit, Greenland (collected during 1992–1996 summer field seasons) and changes in air mass transport pathways and source regions, as well as variations in aerosol source strength. Transport patterns and source regions are determined through 10-day isentropic backward air mass trajectories during a 1 month (late May to late June) common season over the 5 …

Chemical Bonding, Elasticity, And Valence Force Field Models: A Case Study For Α-Pt2si And Ptsi, Gus L. W. Hart, J. E. Klepeis, O. Beckstein, O. Pankratov

Faculty Publications

We have carried out a detailed study of the chemical bonding for two room-temperature stable platinum silicide phases, tetragonal α-Pt2Si. These elements of the bonding are further analyzed by constructing valence force field models using the results from recent first principles calculations of the six (nine) independent, nonzero elastic constants of α-Pt2Si (PtSi). The resulting volume-, radial-, and angular-dependent force constants provide insight into the relative strength of various bonding elements as well as the trends observed in the elastic constants themselves. The valence force field analysis yields quantitative information about the nature of the chemical bonding that is not …

Poynting's Theorem And Luminal Total Energy Transport In Passive Dielectric Media, Scott Glasgow, Michael Ware, Justin Peatross

Faculty Publications

Without approximation the energy density in Poynting's theorem for the generally dispersive and passive dielectric medium is demonstrated to be a system total dynamical energy density. Thus the density in Poynting's theorem is a conserved form that by virtue of its positive definiteness prescribes important qualitative and quantitative features of the medium-field dynamics by rendering the system dynamically closed. This fully three-dimensional result, applicable to anisotropic and inhomogeneous media, is model independent, relying solely on the complex-analytic consequences of causality and passivity. As direct applications of this result, we show 1 that a causal medium responds to a virtual, instantaneous …

Threshold Effects On Angular Distributions For Multiphoton Detachment By Intense Elliptically Polarized Light, Bogdan Borca, M.V. Frolov, N. L. Manakov, Anthony F. Starace

Anthony F. Starace Publications

Unusual threshold effects are found theoretically in the frequency and intensity dependence of angular distributions produced by an elliptically polarized laser as well as in the elliptic dichroism parameter, which measures the asymmetry of the angular distribution.

The Role Of Predation In Wildlife Population Dynamics, Eric M. Gese, Frederick F. Knowlton

United States Department of Agriculture Wildlife Services: Staff Publications

The role predation plays in the dynamics of prey populations is controversial. Our understandings of predator-prey relationships is complicated by a multitude of factors in the environment and a general lack of knowledge of most ecological systems. Various other factors, besides predation, may regulate or limit prey populations, and various factors influence the degree to which predation affects prey populations. Furthermore, some factors may create time lags, or even cause generational effects, that go unnoticed. Herein, we review the role of predation in wildlife population dynamics, some of the factors influencing predator-prey interactions, and attempt to indicate where the professional …

Interpreting Remote Sensing Nox Measurements (Presentation), Robert Slott, Donald H. Stedman, Sajal S. Pokharel

Fuel Efficiency Automobile Test Publications

No abstract provided.

Measurement Of DΣ/Dm And Forward-Backward Charge Asymmetry For High-Mass Drell-Yan E+E- Pairs From Pp̅ Collisions At √S = 1.8 Tev, T. Affolder, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

We report on a measurement of the mass dependence of the forward-backward charge asymmetry, A_FB, and production cross section dσ /dM for e⁺e^- pairs with mass M_ee> 40 GeV/c². The data sample consists of 108 pb^-1 of pp̅ collisions at √s= 1.8 TeV taken by the Collider Detector at Fermilab during 1992–1995. The measured asymmetry and dσ/dM are compared with the predictions of the standard model and a model with an extra Z′ gauge boson.

Comparing The Sfi Peculiar Velocities With The Pscz Gravity Field: A Velmod Analysis, E. Branchini, W. Freudling, L. N. Da Costa, C. S. Frenk, R. Giovanelli, M. P. Haynes, J. J. Salzer, G. Wegner, I. Zehavi

Dartmouth Scholarship

We compare the peculiar velocities derived from the I-band Tully–Fisher (TF) relation for 989 field spiral galaxies in the SFI catalogue with the predicted velocity field derived from the IRAS PSCz galaxy redshift survey. We assume linear gravitational instability theory and apply the maximum likelihood technique, VELMOD to SFI galaxies within a redshift cz LG =6000 km s⁻¹. The resulting calibration of the TF relation is consistent with a previous, independent calibration for a similar sample of spirals residing in clusters. Our analysis provides an accurate estimate of the quantity β_I ≡ Ω_m^{0.6 …}

Fabrication Of Chromium Oxide Nanoparticles By Laser-Induced Deposition From Solution, Z.C. Zhong, R.H. Cheng, Jocelyn Bosley, Peter A. Dowben, David J. Sellmyer

David Sellmyer Publications

We have successfully deposited well-dispersed nanoscale chromium oxide particles by laser-induced solution deposition (LISD) from solution with CrCl₂ and organic solvents. The particles have narrow distributions about three sizes: 230, 350 and 400 nm and are uniform in composition and contain little contamination. We show that LISD is a new technique for producing nanoparticle chromium oxides with uniform composition, controllable size and high yield.

Three-Jet Production In Diffractive Deep Inelastic Scattering At Hera, S. Chekanov, M. Derrick, D. Krakauer, S. Magill, B. Musgrave, A. Pellegrino, J. Repond, R. Yoshida, Margarita C. K. Mattingly, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, G. Levi, A. Margotti, T. Massam, R. Nania, F. Palmonari, A. Pesci, G. Sartorelli

Faculty Publications

Three-jet production in the reaction ep → eXp has been studied with the ZEUS detector at HERA using an integrated luminosity of 42.74 pb-1.The data were measured in the kinematic region 5 < Q2 < 100 GeV2, 200 < W < 250 GeV and 23 < MX < 40 GeV. The diffractive signal was selected by requiring a large rapidity gap in the outgoing proton direction. Jets were reconstructed in the centre-of-mass system of X using the exclusive kT-algorithm. A sample of three-jet events in diffraction has been identified. Differential cross sections were measured as a function of the jet pseudorapidity and jet transverse momentum with respect to the virtual photon-pomeron axis. The jets going in the pomeron direction are broader than those going in the virtual-photon direction. This is consistent with models predicting that gluons are predominantly produced in the pomeron direction and quarks in the virtual-photon direction. © 2001 Elsevier Science B.V. All rights reserved.

Enhanced Double Ionization With Circularly Polarized Light, Glen D. Gillen, M. A. Walker, L. D. Van Woerkom

Physics

Using 120-fs, 800-nm Ti:sapphire laser pulses, ionic yields of singly and doubly charged magnesium ions were measured as a function of intensity and laser field ellipticity. A clear “nonsequential” enhancement of the doubly charged ion is observed for circularly polarized light in addition to linearly polarized light. Over the entire intensity range the double-ionization yield is considerably higher for linear polarization than it is for circular polarization.

Magnetic Properties Of The Mnbi Intermetallic Compound, Jinbo Yang, Kishore Kamaraju, William B. Yelon, William Joseph James, Qingsheng Cai, A. Bollero

Physics Faculty Research & Creative Works

A MnBi alloy containing over 90 wt% low-temperature phase (LTP) has been obtained by high-temperature sintering and magnetic purification. The coercivity of the bonded MnBi magnet increases with increasing temperatures. A coercivity of 2.0 T has been achieved at 400 K. The maximum energy product (BH)_max; of the magnet is 7.7 MGOe (61 kJ/m³) and 4.6 MGOe (37 kJ/m³) at room temperature and 400 K, respectively. Neutron diffraction and magnetic data reveal a spin reorientation, which gives rise to low anisotropy fields and coercivity at lower temperatures for the LTP MnBi alloy.

Recoil Momentum Spectroscopy Of Highly Charged Ion Collisions On Magneto-Optically Trapped Na, J. W. Turkstra, R. Hoekstra, S. Knoop, D. Meyer, R. Morgenstern, Ronald E. Olson

Physics Faculty Research & Creative Works

An attempt was made to derive new generation of cold targets for cold target recoil oil momentum spectroscopy (COLTRIMS) experiments. The ultracold targets were obtained by laser cooling and trapping in a magneto-optical trap (MOT). Impact parameter sensitive information about multielectron capture processes was obtained.

Universal Negative Poisson Ratio Of Self Avoiding Fixed Connectivity Membranes, Mark Bowick, Angelo Cacciuto, G. Thorleifsson, A. Travesset

Physics - All Scholarship

We determine the Poisson ratio of self-avoiding fixed-connectivity membranes, modeled as impenetrable plaquettes, to be sigma=-0.37(6), in statistical agreement with the Poisson ratio of phantom fixed-connectivity membranes sigma=-0.32(4). Together with the equality of critical exponents, this result implies a unique universality class for fixed-connectivity membranes. Our findings thus establish that physical fixed-connectivity membranes provide a wide class of auxetic (negative Poisson ratio) materials with significant potential applications in materials science.

Validation Of Land Surface Models Using Satellite-Derived Surface Temperature, Joshua Rhoads, Ralph Dubayah, Dennis Lettenmaier, Greg O'Donnell, Venkataraman Lakshmi

Faculty Publications

This research examines the feasibility of using remotely sensed surface temperature for validation and updating of land surface hydrologic models. Surface temperature simulated by the Variable Infiltration Capacity (VIC) hydrologie model is compared over the Arkansas-Red River basin with surface temperature retrievals from TOVS and GOES. The results show that modeled and satellite-derived surface temperatures agree well when aggregated in space or time. In particular, monthly mean temperatures agree on the pixel scale, and basin mean temperatures agree instantaneously. At the pixel scale, however, surface temperatures from both satellites were found to have higher spatial and temporal variabilities than the …

Modelling The Trappability Of Tsetse, Glossina Fuscipes Fuscipes, In Relation To Distance From Their Natural Habitats, Adedapo Odulaja, Mohamed M. Mohamed-Ahmed

All Peer-Reviewed Publications

The log-logistic probability distribution function was employed to model trappability of Glossina fuscipes fuscipes, with respect to distance from the edge of two types of habitat. The parameters of the model were obtained using the nonlinear maximum likelihood approach. Asymptotic standard errors of the maximum likelihood estimates were computed for the parameters, and the X2 goodness-of-fit test used to assess the predicted trap catches. Simulation technique was used to estimate the radius of attraction of the unbaited biconical trap for the fly, taking the efficiency of the trap into consideration. The log-logistic model fitted well to a series of observed …

Plasma Transport At The Magnetospheric Boundary Due To Reconnection In Kelvin-Helmholtz Vortices, K. Nykyri, A. Otto

Publications

The Kelvin-Helmholtz( KH) mode has long been considered for viscous interaction at the magnetospheric boundary but it is not expected to produce significant mass transport. The presented results indicate that the Kelvin- Helmholtz instability can indeed cause a transfer of mass into the magnetotail during times of northward IMF. The vortex motion of KH waves can generate a strongly twisted magnetic field with multiple current layers. Magnetic reconnection in the strong current layers inside the vortices can detach high density plasma filaments from the magnetosheath. This may explain observed high density and low temperature filaments in the magnetosphere and the …