Physical Sciences and Mathematics Commons^™

Scattering Of Low- To Intermediate-Energy Positrons From Molecular Hydrogen, David D. Reid, William B. Klann, J. M. Wadehra

Physics and Astronomy Faculty Research Publications

Using a complex model potential, we have calculated the total, integrated elastic, momentum transfer, absorption, and differential cross sections for positrons scattered from molecular hydrogen. The widely available software package GAUSSIAN is used to generate the radial electronic charge density of the molecule which is used to produce the interaction potentials. The quasifree absorption potential, previously developed and used for positron-atom scattering, is extended to positron scattering from molecular targets. It is shown that this model potential approach produces accurate results even into the low-energy regime.

Signature Of Electron Capture In Iron‐Rich Ejecta Of Sn 2003du, Peter Hoflich, Christopher L. Gerardy, Ken-Ichi Nomoto, Kentaro Motohara, Robert A. Fesen

Dartmouth Scholarship

Late-time near-infrared and optical spectra of the normal-bright Type Ia supernova 2003du about 300 days after the explosion are presented. At this late epoch, the emission profiles of well-isolated [Fe II] lines (in particular that of the strong 1.644 μm feature) trace out the global kinematic distribution of radioactive material in the expanding supernova ejecta. In SN 2003du, the 1.644 μm [Fe II] line seems to show a flat-topped profile, indicative of a thick but hollow-centered expanding shell, rather than a strongly peaked profile that would be expected from a "center-filled" distribution. Based on detailed models for exploding Chandrasekhar-mass white …

A Study Of Umts Turbo Codes Across Space Time Spreading Channel With The Case Of M = 1 And M = 2, I. S. Raad, Peter James Vial, Tadeusz A. Wysocki

Faculty of Informatics - Papers (Archive)

The study presented in this paper is that of Universal Mobile Telecommunications Systems (UMTS) Turbo Codes across Space Time Spreading channel with one transmitter antenna, one receiver (m = 1) and two transmitter antennas and one receiver (m = 2) to see to what extent the bit error rate (BER) can be improved. Using the Max-log decoding algorithm and 12 iterations it is shown in the simulation results that an extra 5 dB is achievable.

Extending Asterism Decoding To Qam And Its Complexity In Rician Fading Mimo Systems, P. Conder, Tadeusz A. Wysocki

Faculty of Informatics - Papers (Archive)

The area of Multiple Input Multiple Output (MIMO) communications systems has received enormous attention recently as they can provide a roughly linear increase in data rate by using Multiple Transmit and Receive antennas. The optimal detection strategy for a MIMO receiver is to perform a Maximum-Likelihood (ML) search over all possible transmitted symbol combinations has an exponential complexity when the constellation size of number of transmit antennas increase. A number of sub-optimal decoders, such as VBLAST, provide linear decoding only where the number of receive antennas is at least equal to the number of transmit antennas . Asterism decoding proposed …

Load-Balanced Route Discovery For Mobile Ad Hoc Networks, Mehran Abolhasan, Justin Lipman, Tadeusz A. Wysocki

Faculty of Informatics - Papers (Archive)

This paper presents Flow-Aware Routing Protocol (FARP), a new routing strategy designed to improve load balancing and scalability in mobile ad hoc networks. FARP is a hop-by-hop routing protocol, which introduces a flow-aware route discovery strategy to reduce the number of control overheads propagating through the network and distributes the flow of data through least congested nodes to balance the network traffic. FARP was implemented in Glomosim and compared with AODV. To investigate the load distribution capability of FARP new performance metrics were introduced to measure the data packet flow distribution capability of the each routing protocol. The simulation results …

Observations On The Message Integrity Code In Ieee802.11wireless Lans, Jianyong Huang, Willy Susilo, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

This paper surveys the security of the message integrity code used in the IEEE802.11 Wireless LANs. To address the security flaws of Wired Equivalent Privacy (WEP), the IEEE802.11i draft defines two data confidentiality and integrity protocols, Temporal Key Integrity Protocol (TKIP) and Counter-Mode-CBC-MAC Protocol (CCMP). TKIP is based on RC4, andCCMP is based on the AES cipher. TKIP includes a keyed hash functions, called Michael, as the messag integrity code. The aim of this paper is to summarise the recent research results of Michael and analyse the practicability of two attacks against Michael.

Intranasal Vaccination With Streptococcal Fibronectin Binding Protein Sfb1 Fails To Prevent Growth And Dissemination Of Streptococcus Pyogenes In A Murine Skin Infection Model, Jason D. Mcarthur, E. Medina, J. Chin, B. J. Currie, K. S. Sriprakash, S. R. Talay, G. S. Chhatwal, Mark J. Walker

Faculty of Science - Papers (Archive)

Fibronectin binding protein F1 (Sfb1) of Streptococcus pyogenes (group A streptococcus [GAS]) is a well-characterized adhesin that has been shown to induce protection in mice against a lethal intranasal GAS challenge after intranasal immunization with cholera toxin B subunit (CTB) as adjuvant. With a murine skin infection model, we have shown that Sfb1/CTB vaccination neither elicits opsonizing antibodies nor prevents systemic bacterial growth and dissemination to internal organs after a subcutaneous GAS challenge. These results indicate that an Sfb1-based vaccine should be complemented with additional protective antigens in order to be used in areas such as the tropical north of …

Magnetoelectronics With Magnetoelectrics, Christian Binek, Bernard Doudin

Christian Binek Publications

Magnetoelectric films are proposed as key components for spintronic applications. The net magnetic moment created by an electric field in a magnetoelectric thin film influences the magnetization state of a neighbouring ferromagnetic layer through exchange coupling. Pure electrical control of magnetic confi gurations of giant magnetoresistance spin valves and tunnelling magnetoresistance elements is therefore achievable. Estimates based on documented magnetoelectric tensor values show that exchange fields reaching 100 mT can be obtained. We propose a mechanism alternative to current-induced magnetization switching, providing access to a wide range of device impedance values and opening the possibility of simple logic functions.

Inelastic Electron Tunneling Via Molecular Vibrations In Single-Molecule Transistors, L H. Yu, Z K. Keane, Jacob W. Ciszek, L Cheng, M P. Stewart, J M. Tour, D Natelson

Chemistry: Faculty Publications and Other Works

In single-molecule transistors, we observe inelastic cotunneling features that correspond energetically to vibrational excitations of the molecule, as determined by Raman and infrared spectroscopy. This is a form of inelastic electron tunneling spectroscopy of single molecules, with the transistor geometry allowing in situ tuning of the electronic states via a gate electrode. The vibrational features shift and change shape as the electronic levels are tuned near resonance, indicating significant modification of the vibrational states. When the molecule contains an unpaired electron, we also observe vibrational satellite features around the Kondo resonance.

Minimum Power Configuration In Wireless Sensor Networks, Guoliang Xing, Chenyang Lu, Ying Zhang, Qingfeng Huang, Robert Pless

All Computer Science and Engineering Research

This paper proposes the minimum power configuration (MPC) approach to energy conservation in wireless sensor networks. In sharp contrast to earlier research that treats topology control, power-aware routing, and sleep management in isolation, MPC integrates them as a joint optimization prob-lem in which the power configurationof a network consists of a set of active nodes and the transmission powers of the nodes. We show through analysis that the minimum power configu-ration of a network is inherently dependent on the data rates of sources. We propose several approximation algorithms with provable performance bounds compared to the optimal solu-tion, and a practical …

Coordinating Heterogeneous Web Services Through Handhelds Using Syd?S Wrapper Framework, Mohini Padhye

Computer Science Theses

Tying web services together to build large, distributed, collaborative applications has gathered noticeable momentum and a lot of research is being put in it. Along with composition of the web services, coordination is one key aspect that has been considered keenly. Many frameworks, languages and protocols have been proposed for web service composition and coordination. With the advancement in wireless technology and rapid deployment of mobile services, collaborative application development for small devices using such composed web services finds a new research area. Much less work has been done in the area of web service coordination for mobile environment. In …

Requirement Elicitation Of Large Web Projects., David E. Frazier

Electronic Theses and Dissertations

One of the most important aspects of developing a large Web-based project is getting the correct requirements from the client. Time and money can be lost if the requirements are incomplete or inaccurate. Traditional Web design sources tend to gloss over this important activity.

Software engineering is a mature field that can help in the quest for more complete and accurate requirement gathering. This paper explores the ways that traditional software engineering techniques can be applied to Web projects. A methodology is presented based on both existing and new techniques. Several experiments are conducted to determine the usefulness of each …

Image Quality Assessment Using A Neural Network Approach, Abdesselam Bouzerdoum, A. Havstad, A. Beghdadi

Faculty of Informatics - Papers (Archive)

In this paper, we propose a neural network approach to image quality assessment. In particular, the neural network measures the quality of an image by predicting the mean opinion score (MOS) of human observers, using a set of key features extracted from the original and test images. Experimental results, using 352 JPEG/JPEG2000 compressed images, show that the neural network outputs correlate highly with the MOS scores, and therefore, the neural network can easily serve as a correlate to subjective image quality assessment. Using 10-fold cross-validation, the predicted MOS values have a linear correlation coefficient of 0.9744, a Spearman ranked correlation …

Timing And Nature Of The Deepening Of The Tasmanian Gateway, Catherine E. Stickley, Henk Brinkhuis, Stephen A. Schellenberg, Appy Sluijs, Ursula Röhl, Michael Fuller, Marianne Grauert, Matthew Huber, Jeroen Warnaar, Graham L. Williams

Department of Earth, Atmospheric, and Planetary Sciences Faculty Publications

Tectonic changes that produced a deep Tasmanian Gateway between Australia and Antarctica are widely invoked as the major mechanism for Antarctic cryosphere growth and Antarctic Circumpolar Current (ACC) development during the Eocene/Oligocene (E/O) transition (∼34–33 Ma). Ocean Drilling Program (ODP) Leg 189 recovered near-continuous marine sedimentary records across the E/O transition interval at four sites around Tasmania. These records are largely barren of calcareous microfossils but contain a rich record of siliceous- and organic-walled marine microfossils. In this study we integrate micropaleontological, sedimentological, geochemical, and paleomagnetic data from Site 1172 (East Tasman Plateau) to identify four distinct phases (A–D) in …

Eocene Circulation Of The Southern Ocean: Was Antarctica Kept Warm By Subtropical Waters?, Matthew Huber, Henk Brinkhuis, Catherine E. Stickley, Kristofer Döös, Appy Sluijs

Department of Earth, Atmospheric, and Planetary Sciences Faculty Publications

Near the Eocene's close (∼34 million years ago), the climate system underwent one of the largest shifts in Earth's history: Antarctic terrestrial ice sheets suddenly grew and ocean productivity patterns changed. Previous studies conjectured that poleward penetration of warm, subtropical currents, the East Australian Current (EAC) in particular, caused Eocene Antarctic warmth. Late Eocene opening of an ocean gateway between Australia and Antarctica was conjectured to have disrupted the EAC, cooled Antarctica, and allowed ice sheets to develop. Here we reconstruct Eocene paleoceanographic circulation in the Tasmanian region, using (1) biogeographical distributions of phytoplankton, including data from recently drilled Ocean …

Variable Resolution Discretization In The Joint Space, Christopher K. Monson, Kevin Seppi, David Wingate, Todd S. Peterson

Faculty Publications

We present JoSTLe, an algorithm that performs value iteration on control problems with continuous actions, allowing this useful reinforcement learning technique to be applied to problems where a priori action discretization is inadequate. The algorithm is an extension of a variable resolution technique that works for problems with continuous states and discrete actions. Results are given that indicate that JoSTLe is a promising step toward reinforcement learning in a fully continuous domain.

Maldi-Tof Ms Data Processing Using Wavelets, Splines And Clustering Techniques., Shuo Chen

Electronic Theses and Dissertations

Mass Spectrometry, especially matrix assisted laser desorption/ionization (MALDI) time of flight (TOF), is emerging as a leading technique in the proteomics revolution. It can be used to find disease-related protein patterns in mixtures of proteins derived from easily obtained samples. In this paper, a novel algorithm for MALDI-TOF MS data processing is developed. The software design includes the application of splines for data smoothing and baseline correction, wavelets for adaptive denoising, multivariable statistics techniques such as clustering analysis, and signal processing techniques to evaluate the complicated biological signals. A MatLab implementation shows the processing steps consecutively including step-interval unification, adaptive …

Kinetics And Mechanism Of The Catalysis Of The Decomposition Of Hydrogen Peroxide By Schiff Base Complexes Of Copper(Ii)., Timothy Kum Beng

Electronic Theses and Dissertations

Spectroscopic studies have been used to describe the mechanism of the decomposition of hydrogen peroxide by solutions of a dimeric Cu(II) complex of a dissymetric Schiff base, [CuSALAD]₂.H₂O, and imidazole or methyl substituted imidazoles, B, which form monomeric CuSALAD.B₂ complexes, in aqueous ethanol solvent. Freezing point depression and vapor pressure lowering studies were carried out to confirm the dimeric nature of the [CuSALAD]₂.H₂O complex that had been previously reported. The stoichiometry of the [CuSALAD]₂.H₂O-imidazole equilibrium was extensively studied pointing to a 1:4 stoichiometry. The CuSALAD.B₂ adducts …

A Bayesian Technique For Task Localization In Multiple Goal Markov Decision Processes, James Carroll, Kevin Seppi

Faculty Publications

In a reinforcement learning task library system for Multiple Goal Markov Decision Process (MGMDP), localization in the task space allows the agent to determine whether a given task is already in its library in order to exploit previously learned experience. Task localization in MGMDPs can be accomplished through a Bayesian approach, however a trivial approach fails when the rewards are not distributed normally. This can be overcome through our Bayesian Task Localization Technique (BTLT).

Dietary Carbohydrates And Breast Cancer Risk: A Prospective Study Of The Roles Of Overall Glycemic Index And Glycemic Load, Stephanie A. Navarro Silvera, Meera Jain, Geoffrey R. Howe, Anthony B. Miller, Thomas E. Rohan

Department of Public Health Scholarship and Creative Works

We examined breast cancer risk in association with an overall glycemic index (GI), glycemic load (GL), and dietary carbohydrate and sugar intake in a prospective cohort of 49,613 Canadian women enrolled in the National Breast Screening Study who completed a self-administered food frequency questionnaire between 1980 and 1985. Linkages to national mortality and cancer databases yielded data on deaths and cancer incidence, with follow-up ending between 1998 and 2000. During a mean follow-up of 16.6 years, we observed 1,461 incident breast cancer cases. GI, GL, total carbohydrate, and total sugar intake were not associated with breast cancer risk in the …

Estimating Percentile-Specific Causal Effects: A Case Study Of Micronutrient Supplementation, Birth Weight, And Infant Mortality, Francesca Dominici, Scott L. Zeger, Giovanni Parmigiani, Joanne Katz, Parul Christian

Johns Hopkins University, Dept. of Biostatistics Working Papers

In developing countries, higher infant mortality is partially caused by poor maternal and fetal nutrition. Clinical trials of micronutrient supplementation are aimed at reducing the risk of infant mortality by increasing birth weight. Because infant mortality is greatest among the low birth weight infants (LBW) (• 2500 grams), an effective intervention may need to increase the birth weight among the smallest babies. Although it has been demonstrated that supplementation increases the birth weight in a trial conducted in Nepal, there is inconclusive evidence that the supplementation improves their survival. It has been hypothesized that a potential benefit of the treatment …

A Hybrid Newton-Type Method For The Linear Regression In Case-Cohort Studies, Menggang Yu, Bin Nan

The University of Michigan Department of Biostatistics Working Paper Series

Case-cohort designs are increasingly commonly used in large epidemiological cohort studies. Nan, Yu, and Kalbeisch (2004) provided the asymptotic results for censored linear regression models in case-cohort studies. In this article, we consider computational aspects of their proposed rank based estimating methods. We show that the rank based discontinuous estimating functions for case-cohort studies are monotone, a property established for cohort data in the literature, when generalized Gehan type of weights are used. Though the estimating problem can be formulated to a linear programming problem as that for cohort data, due to its easily uncontrollable large scale even for a …

An Informatics Search For The Low-Molecular Weight Chromium-Binding Peptide, Deendayal Dinakarpandian, Vincent Morrissette, Shveta Chaudhary, Kambiz Amini, Brian Bennett, J David Van Horn

Physics Faculty Research and Publications

Background

The amino acid composition of a low molecular weight chromium binding peptide (LMWCr), isolated from bovine liver, is reportedly E:G:C:D::4:2:2:2, though its sequence has not been discovered. There is some controversy surrounding the exact biochemical forms and the action of Cr(III) in biological systems; the topic has been the subject of many experimental reports and continues to be investigated. Clarification of Cr-protein interactions will further understanding Cr(III) biochemistry and provide a basis for novel therapies based on metallocomplexes or small molecules.

Results

A genomic search of the non-redundant database for all possible decapeptides of the reported composition yields three …

Gas-Phase Chemical Characteristics Of Asian Emission Plumes Observed During Itct 2k2 Over The Eastern North Pacific Ocean, J. B. Nowak, D. D. Parrish, J. A. Neuman, J. S. Holloway, O. R. Cooper, T. B. Ryerson, Jr K. Nicks, F. Flocke, J. M. Roberts, E. Atlas, J. A. De Gouw, Stephen G. Donnelly Ph.D., E. Dunlea, G. Hübler, L. G. Huey, S. Schauffler, D. J. Tanner, C. Warneke, F. C. Fehsenfeld

Chemistry Faculty Publications

The gas-phase chemical characteristics of emission plumes transported from Asia across the Pacific Ocean observed during the Intercontinental Transport and Chemical Transformation experiment in 2002 (ITCT 2K2) are described. Plumes measured in the troposphere from an aircraft were separated from the background air in data analysis using 1-s measurements of carbon monoxide (CO), total reactive nitrogen (NOy), and other gasphase species along with back trajectory analysis. On the basis of these measurements, Asian transport plumes with CO mixing ratios greater than 150 ppbv were observed on seven flights. Correlations between 1-s observations of CO, ozone (O3), and NOy are used …

Chemical Composition Of Air Masses Transported From Asia To The U.S. West Coast During Itct 2k2: Fossil Fuel Combustion Versus Biomass-Burning Signatures, J. A. De Gouw, O. R. Cooper, C. Warneke, P. K. Hudson, F. C. Fehsenfeld, J. S. Holloway, G. Hübler, Jr K. Nicks, J. B. Nowak, D. D. Parrish, T. B. Ryerson, E. L. Atlas, Stephen G. Donnelly Ph.D., S. M. Schauffler, V. Stroud, K. Johnson, G. R. Carmichael, D. G. Streets

Chemistry Faculty Publications

As part of the Intercontinental Transport and Chemical Transformation experiment in 2002 (ITCT 2K2), a National Oceanic and Atmospheric Administration (NOAA) WP-3D research aircraft was used to study the long-range transport of Asian air masses toward the west coast of North America. During research flights on 5 and 17 May, strong enhancements of carbon monoxide (CO) and other species were observed in air masses that had been transported from Asia. The hydrocarbon composition of the air masses indicated that the highest CO levels were related to fossil fuel use. During the flights on 5 and 17 May and other days, …

Changes In The Photochemical Environment Of The Temperate North Pacific Troposphere In Response To Increased Asian Emissions, D. D. Parrish, E. J. Dunlea, E. L. Atlas, S. Schauffler, Stephen G. Donnelly Ph.D., V. Stroud, A. H. Goldstein, D. B. Millet, M. Mckay, D. A. Jaffe, H. U. Price, P. G. Hess, F. Flocke, J. M. Roberts

Chemistry Faculty Publications

Measurements during the Intercontinental Transport and Chemical Transformation 2002 (ITCT 2K2) field study characterized the springtime, eastern Pacific ozone distribution at two ground sites, from the National Oceanic and Atmospheric Administration WP-3D aircraft, and from a light aircraft operated by the University of Washington. D. Jaffe and colleagues compared the 2002 ozone distribution with measurements made in the region over the two previous decades and show that average ozone levels over the eastern midlatitude Pacific have systematically increased by ∼10 ppbv in the last two decades. Here we provide substantial evidence that a marked change in the photochemical environment in …

Multiscale Simulations Of Tropospheric Chemistry In The Eastern Pacific And On The U.S. West Coast During Spring 2002, Youhua Tang, Gregory R. Carmichael, Larry W. Horowitz, Itsushi Uno, Jung Hun Woo, David G. Streets, Donald Dabdub, Gakuji Kurata, Adrian Sandu, James Allan, Elliot Atlas, Frank Flocke, Lewis Gregory Huey, Roger O. Jakoubek, Dylan B. Millet, Patricia K. Quinn, James M. Roberts, Douglas R. Worsnop, Allen Goldstein, Stephen G. Donnelly Ph.D., Sue Schauffler, Verity Stroud, Kristen Johnson, Melody A. Avery, Hanwant B. Singh, Eric C. Apel

Chemistry Faculty Publications

Regional modeling analysis for the Intercontinental Transport and Chemical Transformation 2002 (ITCT 2K2) experiment over the eastern Pacific and U.S. West Coast is performed using a multiscale modeling system, including the regional tracer model Chemical Weather Forecasting System (CFORS), the Sulfur Transport and Emissions Model 2003 (STEM-2K3) regional chemical transport model, and an off-line coupling with the Model of Ozone and Related Chemical Tracers (MOZART) global chemical transport model. CO regional tracers calculated online in the CFORS model are used to identify aircraft measurement periods with Asian influences. Asian-influenced air masses measured by the National Oceanic and Atmospheric Administration (NOAA) …

Azimuthal Anisotropy And Correlations At Large Transverse Momenta In P+P And Au+Au Collisions At √SNn=200 Gev, Star Collaboration, T.D. Gutierrez

Physics

Results on high transverse momentum charged particle emission with respect to the reaction plane are presented for Au+Au collisions at √s_NN=200  GeV. Two- and four-particle correlations results are presented as well as a comparison of azimuthal correlations in Au+Au collisions to those in p+p at the same energy. The elliptic anisotropy v₂ is found to reach its maximum at pt∼3  GeV/c, then decrease slowly and remain significant up to p_t≈7–10  GeV/c. Stronger suppression is found in the back-to-back high-p_t particle correlations for particles emitted out of plane compared to those emitted in plane. The …

Multiple Testing Procedures For Controlling Tail Probability Error Rates, Sandrine Dudoit, Mark J. Van Der Laan, Merrill D. Birkner

U.C. Berkeley Division of Biostatistics Working Paper Series

The present article discusses and compares multiple testing procedures (MTP) for controlling Type I error rates defined as tail probabilities for the number (gFWER) and proportion (TPPFP) of false positives among the rejected hypotheses. Specifically, we consider the gFWER- and TPPFP-controlling MTPs proposed recently by Lehmann & Romano (2004) and in a series of four articles by Dudoit et al. (2004), van der Laan et al. (2004b,a), and Pollard & van der Laan (2004). The former Lehmann & Romano (2004) procedures are marginal, in the sense that they are based solely on the marginal distributions of the test statistics, i.e., …

Chemical Analyses In Support Of Yucca Mountain Studies, Jeanette Daniels, Klaus J. Stetzenbach, Drew Coleman, Amy J. Smiecinski, Raymond E. Keeler

Publications (YM)

The objective of this task “Chemical Analyses in Support of Yucca Mountain Studies” is to provide the Department of Energy (DOE) with data and reports from comprehensive chemical analyses of waters sampled from the wells of the Nye County Early Warning Drilling Program (NCEWDP), the Inyo County’s Drilling Program, and the Nye county Tracer Test. In addition, this task will be used to provide other laboratory support needs as they arise within the Yucca Mountain Project. This support is provided by the Harry Reid Center for Environmental Studies (HRC) at University of Nevada, Las Vegas (UNLV), which is part of …