Physical Sciences and Mathematics Commons^™

Landscape Limnology: Nutrient Fluxes & Biotic Stability In Complex Mountain Watersheds, Wayne A. Wurtsbaugh, Michelle Kang, Dave M. Epstein

Watershed Sciences Faculty Publications

No abstract provided.

Subunit-Selective Interrogation Of Co Recombination In Carbonmonoxy Hemoglobin By Isotope-Edited Time-Resolved Resonance Raman Spectroscopy, Gurusamy Balakrishnan, Xiaojie Zhao, Edyta Podstawska, Leonard M. Proniewicz, James R. Kincaid, Thomas G. Spiro

Chemistry Faculty Research and Publications

Hemoglobin (Hb) is an allosteric tetrameric protein made up of αβ heterodimers. The α and β chains are similar, but are chemically and structurally distinct. To investigate dynamical differences between the chains, we have prepared tetramers in which the chains are isotopically distinguishable, via reconstitution with ¹⁵N-heme. Ligand recombination and heme structural evolution, following HbCO dissociation, was monitored with chain selectivity by resonance Raman (RR) spectroscopy. For α but not for β chains, the frequency of the ν₄ porphyrin breathing mode increased on the microsecond time scale. This increase is a manifestation of proximal tension in the Hb …

The Nasa-Uc Eta-Earth Program. I. A Super-Earth Orbiting Hd 7924, Andrew W. Howard, John Asher Johnson, Geoffrey W. Marcy, Debra A. Fischer, Jason T. Wright, Gregory W. Henry, Matthew J. Giguere, Howard Isaacson, Jeff A. Valenti, Jay Anderson, Nikolai Piskunov

Information Systems and Engineering Management Research Publications

We report the discovery of the first low-mass planet to emerge from the NASA-UC Eta-Earth Program, a super-Earth orbiting the K0 dwarf HD 7924. Keplerian modeling of precise Doppler radial velocities reveals a planet with minimum mass MPsin i = 9.26 M⊕ in a P = 5.398 d orbit. Based on Keck-HIRES measurements from 2001 to 2008, the planet is robustly detected with an estimated false alarm probability of less than 0.001. Photometric observations using the Automated Photometric Telescopes at Fairborn Observatory show that HD 7924 is photometrically constant over the radial velocity period to 0.19 mmag, supporting the existence …

On The Modification Of An Eigenvalue Problem That Preserves An Eigenspace, Maxim Maumov

Department of Computer Science Technical Reports

No abstract provided.

Nano-Imprinted Thin Films Of Reactive, Azlactone-Containing Polymers: Combining Methods For The Topographic Patterning Of Cell Substrates With Opportunities For Facile Post-Fabrication Chemical Functionalization, Nathaniel J. Fredin, Adam H. Broderick, Maren E. Buck, David M. Lvnn

Chemistry: Faculty Publications

Approaches to the fabrication of surfaces that combine methods for the topographic patterning of soft materials with opportunities for facile, post-fabrication chemical functionalization could contribute significantly to advances in biotechnology and a broad range of other areas. Here, we report methods that can be used to introduce well defined nano- and microscale topographic features to thin films of reactive polymers containing azlactone functionality using nanoimprint lithography (NIL). We demonstrate that NIL can be used to imprint topographic patterns into thin films of poly(2-vinyl-4,4- dimethylazlactone) and a copolymer of methyl methacrylate and 2-vinyl- 4,4-dimethylazlactone using silicon masters having patterns of grooves …

2009 - The Fourteenth Annual Symposium Of Student Scholars

Symposium of Student Scholars Program Books

The full program book from the Fourteenth Annual Symposium of Student Scholars, held on April 13, 2009. Includes abstracts from the presentations and posters.

Mind Map, William Osei-Poku

William Osei-Poku

No abstract provided.

Making An Xbox360 Video Game, Daniel Frandsen

Honors Theses

In the area of computer science, game design pushes the limits on what is possible in real time graphics. The game must process the entire scene up to sixty times a second, so code techniques that normally work must be adapted to be as efficient as possible. Some challenges cannot be overcome by traditional methods and must be adapted to work in a high-demand environment. In addition to these obstacles, students have limited opportunities to develop games for console platforms due to the cost required for development kits. This paper will explore the process behind developing a game for the …

Encoded Archival Description, William Osei-Poku

William Osei-Poku

No abstract provided.

Composite Likelihood Bayesian Information Criteria For Model Selection In High Dimensional Data, X Gao, Peter Xuekun Song

The University of Michigan Department of Biostatistics Working Paper Series

For high-dimensional data set with complicated dependency structures, the full likelihood approach often renders to intractable computational complexity. This imposes di±culty on model selection as most of the traditionally used information criteria require the evaluation of the full likelihood. We propose a composite likelihood version of the Bayesian information criterion (BIC) and establish its consistency property for the selection of the true underlying model. Under some mild regularity conditions, the proposed BIC is shown to be selection consistent, where the number of potential model parameters is allowed to increase to in¯nity at a certain rate of the sample size. Simulation …

The True Durations Of Starbursts: Hubble Space Telescope Observations Of Three Nearby Dwarf Starburst Galaxies, Kristen B.W. Mcquinn, Evan D. Skillman, John Cannon, Julianne J. Dalcanton, Andrew Dolphin, David Stark, Daniel Weisz

John Cannon

No abstract provided.

A Search For H2O Megamasers In High-Z Type-2 Active Galactic Nuclei, Vardha N. Bennert, Richard Barvainis, Christian Henkel, Robert Antonucci

Physics

We report a search for H₂O megamasers in 274 SDSS type-2 active galactic nuclei (AGNs; 0.3 <z< 0.83), half of which can be classified as type-2 quasi-stellar objects (QSOs) from their [O III] 5007 luminosity, using the Robert C. Byrd Green Bank Telescope (GBT) and the Effelsberg 100 m radio telescope. Apart from the detection of the extremely luminous water vapor megamaser SDSS J080430.99+360718.1, already reported by Barvainis & Antonucci, we do not find any additional line emission. This high rate of nondetections is compared to the water maser luminosity function created from the 78 water maser galaxies known to date and its extrapolation toward the higher luminosities of "gigamasers" that we would have been able to detect given the sensitivity of our survey. The properties of the known water masers are summarized and discussed with respect to the nature of high-z type-2 AGNs and megamasers in general. In the Appendix, we list 173 additional objects (mainly radio galaxies, but also QSOs and galaxies) that were observed with the GBT, the Effelsberg 100 m radio telescope, or Arecibo Observatory without leading to the detection of water maser emission.

The Scope And Limitations Of Intramolecular Nicholas And Pauson-Khand Reactions For The Synthesis Of Tricyclic Oxygen- And Nitrogen-Containing Heterocycles, Kristina D. Closser, Miriam M. Quintal, Kevin M. Shea

Chemistry: Faculty Publications

We studied the scope and limitations of a tandem intramolecular Nicholas/Pauson−Khand strategy for the synthesis of tricyclic oxygen- and nitrogen-containing heterocycles. This methodology enables conversion of simple acyclic starting materials into a series of previously unknown heterocyclic architectures. For the preparation of cyclic ethers (Z = O), tricyclic [5,6,5]- through [5,9,5]-systems (m = 1, n = 1−4) are available with the [5,7,5]- and [5,8,5]-systems amenable to quick and efficient synthesis. Tricyclic [5,7,5]- and [5,8,5]-amine-containing (Z = NTs) heterocycles can be successfully prepared. Attempts to make larger ring systems (Z = O, m = 2; Z = O, n = …

A Generalization Of Auc To An Ordered Multi-Class Diagnosis And Application To Longitudinal Data Analysis On Intellectual Outcome In Pediatric Brain-Tumor Patients, Yi Li

Mathematics Dissertations

Receiver operating characteristic (ROC) curves have been widely used in evaluation of the goodness of the diagnostic method in many study fields, such as disease diagnosis in medicine. The area under the ROC curve (AUC) naturally became one of the most used variables in gauging the goodness of the diagnosis (Mossman, Somoza 1991). Since medical diagnosis often is not dichotomous, the ROC curve and AUC need to be generalized to a multi-dimensional case. The generalization of AUC to multi-class case has been studied by many researchers in the past decade. Most recently, Nakas & Yiannoutsos (2004) considered the ordered d …

Theoretical And Computational Studies Of Interstellar C2nH And Sic2m+1H, Ryan C. Fortenberry

Ryan C. Fortenberry

This work focuses on computation of simulated spectra the C_2nH family (n = f1, 2, : : :g) of carbon chain rad- ical molecules and their silicon analogues, SiC_2m+1H (m = f0, ng), that are potential carriers of the Di_use Interstellar Bands (DIBs). High-level quantum chem- ical computations for the ground- and excited-states of these radicals indicate agreement with experimen- tal data that the ground-state of C₂H is ²Ʃ⁺ while that of C₆H, SiCH, SiC₃H, and SiC₅H is ²π. On the other hand, most of …

Universal Scaling Of Nonequilibrium Transport In The Kondo Regime Of Single Molecule Devices, G D. Scott, Z K. Keane, Jacob W. Ciszek, J M. Tour, D Natelson

Chemistry: Faculty Publications and Other Works

Scaling laws and universality are often associated with systems exhibiting emergent phenomena possessing a characteristic energy scale. We report nonequilibrium transport measurements on two different types of single molecule transistor devices in the Kondo regime. The conductance at low bias and temperature adheres to a scaling function characterized by two parameters. This result, analogous to that reported recently in semiconductor dots with Kondo temperatures two orders of magnitude lower, demonstrates the universality of this scaling form. We compare the extracted values of the scaling coefficients to previous experimental and theoretical results.

Material Properties Of Nanoclay Pvc Composites, Walid Awad, Gunter Beyer, Daphne Benderly, Wouter L. Ijdo, Ponusa Songtipya, Maria Del Mar Jimenez-Gasco, Evangelos Manias, Charles A. Wilkie

Chemistry Faculty Research and Publications

Nanocomposites of poly(vinyl chloride) have been prepared using both hectorite- and bentonite-based organically-modified clays. The organic modification used is tallow-triethanol-ammonium ion. The morphology of the systems was investigated using X-ray diffraction and transmission electron microscopy and these systems show that true nanocomposites, both intercalated and exfoliated systems, are produced. The mechanical properties have been evaluated and the modulus increases upon nanocomposite formation without a significant decrease in tensile strength or elongation at break. Thermal analysis studies using thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis were conducted. Thermal stability of the PVC systems was assessed using a standard thermal …

Joint Ranking For Multilingual Web Search, Wei Gao, Cheng Niu, Ming Zhou, Kam-Fai Wong

Research Collection School Of Computing and Information Systems

Ranking for multilingual information retrieval (MLIR) is a task to rank documents of different languages solely based on their relevancy to the query regardless of query’s language. Existing approaches are focused on combining relevance scores of different retrieval settings, but do not learn the ranking function directly. We approach Web MLIR ranking within the learning-to-rank (L2R) framework. Besides adopting popular L2R algorithms to MLIR, a joint ranking model is created to exploit the correlations among documents, and induce the joint relevance probability for all the documents. Using this method, the relevant documents of one language can be leveraged to improve …

Language Modeling Approaches To Information Retrieval, Protima Banerjee, Hyoil Han

Computer Sciences and Electrical Engineering Faculty Research

This article surveys recent research in the area of language modeling (sometimes called statistical language modeling) approaches to information retrieval. Language modeling is a formal probabilistic retrieval framework with roots in speech recognition and natural language processing. The underlying assumption of language modeling is that human language generation is a random process; the goal is to model that process via a generative statistical model.

In this article, we discuss current research in the application of language modeling to information retrieval, the role of semantics in the language modeling framework, cluster-based language models, use of language modeling for XML retrieval and …

Spin-Polarization In Quantum Wires: Influence Of Dresselhaus Spin-Orbit Interaction And Cross-Section Effects, L. Villegas-Lelovsky, C. Trallero-Giner, Mariama Rebello Sousa Dias, V. Lopez-Richard, G. E. Marques

Physics Faculty Publications

We examine the effects of the full Dresselhaus spin-orbit coupling on laterally confined quantum wire states. An analysis of the relative contributions due to linear, quadratic, and cubic Dresselhaus spin-orbit terms on the energy levels, spin splitting, and spin polarization has been carried out. The effects of wire cross-sectional geometry shapes on the electronic structure are explored. In particular we compared the results of semicylindrical and cylindrical confinements and have found important differences between the spin degeneracy of the ground-state level and the spin-polarization dependence on sign inversion of the free linear momentum quantum number along the wire axis. Different …

Simultaneous Quantitation Of Multiple Classes Of Organohalogen Compounds In Fish Oils With Direct Sample Introduction Comprehensive Two-Dimensional Gas Chromatography And Time-Of-Flight Mass Spectrometry, Eunha Hoh, Steven J. Lehotay, Kristin C. Pangallo, Katerina Mastovska, Helen L. Ngo, Christopher M. Reddy, Walter Vetter

Kristin Pangallo

Nutrient Enrichment Drives Gulf Of Mexico Hypoxia, Donald F. Boesch, Walter R. Boyton, Larry B. Crowder, Robert J. Diaz, Robert W. Howarth, Laurence D. Mee, Scott W. Nixon, Nancy N. Rabalais, Rutger Rosenberg, James G. Sanders, Donald Scavia, R. Eugene Turner

Faculty Publications

No abstract provided.

Photoregulated Release Of Caged Anticancer Drugs From Gold Nanoparticles, Ss Agasti, A Chompoosor, Cc You, P Ghosh, Ck Kim, Vm Rotello

Vincent Rotello

An anticancer drug (5-fluorouracil) was conjugated to the surface of gold nanoparticles through a photocleavable o-nitrobenzyl linkage. In this system, the particle serves as both cage and carrier for the therapeutic, providing a nontoxic conjugate that effectively releases the payload upon long wavelength UV irradiation.

Hr 8257: A Three-Dimensional Orbit And Basic Properties, Francis C. Fekel, Andrew F. Boden, Jocelyn Tomkin, Guillermo Torres

Information Systems and Engineering Management Research Publications

We have used interferometric and spectroscopic observations of HR 8257 to determine a three-dimensional orbit of the system. The orbit has a period of 12.21345 days and an eccentricity of 0.2895. The masses of the F0 and F2 dwarf components are 1.56 and 1.38 M☉, respectively, with fractional errors of 1.4%. Our orbital parallax of 13.632 ± 0.095 mas, corresponding to a distance of 73.4 ± 0.6 pc, differs from the Hipparcos result by just 2% and has a significantly smaller uncertainty. From our spectroscopic observations and spectral energy distribution modeling we determine the component effective temperatures and luminosities to …

Magnetocaloric Properties Of Co/Cr Superlattices, Tathagata Mukherjee, Sarbeswar Sahoo, David J. Sellmyer, Christian Binek

Christian Binek Publications

Nanostructured materials for refrigeration applications are experimentally realized by molecular beam epitaxial growth of Co/Cr superlattices using mean-field theoretical concepts as guiding principles. Magnetocaloric properties are deduced from measurements of the temperature and field dependence of the magnetization of our samples. More generally, the potential of artificial antiferromagnets for near room-temperature refrigeration is explored. The effects of intraplane and interplane exchange interactions on the magnetic phase diagram in Ising-type model systems are revisited in mean-field considerations with special emphasis on tailoring magnetocaloric properties. The experimental results are discussed in light of our theoretical findings, and extrapolations for future improved nanostructures …

Estimating The Effects Of Detection Heterogeneity And Overdispersion On Trends Estimated From Avian Point Counts, Matthew A. Etterson, Gerald J. Niemi, Nicholas P. Danz

United States Environmental Protection Agency: Publications

Point counts are a common method for sampling avian distribution and abundance. Although methods for estimating detection probabilities are available, many analyses use raw counts and do not correct for detectability. We use a removal model of detection within an N-mixture approach to estimate abundance trends corrected for imperfect detection. We compare the corrected trend estimates to those estimated from raw counts for 16 species using 15 years of monitoring data on three national forests in the western Great Lakes, USA. We also tested the effects of overdispersion by modeling both counts and removal mixtures under three statistical distributions: …

Comparing The Use Of Tangible And Graphical Programming Languages For Informal Science Education, Michael S. Horn, Erin T. Solovey, R. Jordan Crouser, Robert J.K. Jacob

Computer Science: Faculty Publications

Much of the work done in the field of tangible interaction has focused on creating tools for learning; however, in many cases, little evidence has been provided that tangible interfaces offer educational benefits compared to more conventional interaction techniques. In this paper, we present a study comparing the use of a tangible and a graphical interface as part of an interactive computer programming and robotics exhibit that we designed for the Boston Museum of Science. In this study, we have collected observations of 260 museum visitors and conducted interviews with 13 family groups. Our results show that visitors found the …

Distance To The Sagittarius Dwarf Galaxy Using Macho Project Rr Lyrae Stars, Andrea Kunder, Brian Chaboyer

Dartmouth Scholarship

We derive the distance to the northern extension of the Sagittarius (Sgr) dwarf spheroidal galaxy from 203 Sgr RR0 Lyrae stars found in the MACHO database. Their distances are determined differentially with respect to 288 Galactic bulge RR0 Lyrae stars also found in the MACHO data. We find a distance modulus difference of 2.41 mag at l = 5^◦ and b =− 8^◦ and that the extension of the Sgr galaxy toward the galactic plane is inclined toward us. Assuming R GC = 8 kpc, this implies the distance to these stars is (m − M) 0 = …

Probabilistic Analysis Of A Differential Equation For Linear Programming, Asa Ben-Hur, Joshua Feinberg, Shmuel Fishman, Hava Siegelmann

Hava Siegelmann

In this paper we address the complexity of solving linear programming problems with a set of differential equations that converge to a fixed point that represents the optimal solution. Assuming a probabilistic model, where the inputs are i.i.d. Gaussian variables, we compute the distribution of the convergence rate to the attracting fixed point. Using the framework of Random Matrix Theory, we derive a simple expression for this distribution in the asymptotic limit of large problem size. In this limit, we find the surprising result that the distribution of the convergence rate is a scaling function of a single variable. This …

Predicting The Socioethical Implications Of Implanting People With Microchips, K. Michael, M.G. Michael

Associate Professor Katina Michael

Privacy, security, trust, control and human rights are all concerns that need to be addressed before widespread diffusion of advanced identification technologies.