Physical Sciences and Mathematics Commons^™

Mixed-Metal Cluster Synthesis: [Re(Co)3(Μ-S2Nc7H4)]2 As A Precursor For Tri- And Tetranuclear 2-Mercaptobenzothiolato Capped Clusters, Shishir Ghosh, Kamrun N. Khanam, Md. Kamal Hossain, G. M. Golzar Hossain, Daniel T. Haworth, Sergey V. Lindeman, Graeme Hogarth, Shariff E. Kabir

Chemistry Faculty Research and Publications

The readily prepared [Re₂(CO)₆(μ-S₂NC₇H₄)₂] (1) reacts with Group 8 trimetallic carbonyl clusters to yield new mixed-metal tri- and tetranuclear clusters. With [Os₃(CO)₁₀(NCMe)₂] at 80 °C the tetranuclear mixed-metal cluster [Os₃Re(CO)₁₃(μ₃-C₇H₄NS₂)] (2) is the only isolated product. With Ru₃(CO)₁₂ products are dependent upon the reaction temperature. At 80 °C, a mixture of tetranuclear mixed-metal [Ru₃Re(CO)₁₃(μ₃-C₇H₄NS₂)] (5) …

Coherence Between The Great Salt Lake Level And The Pacific Quasi-Decadal Oscillation, Shih-Yu (Simon) Wang, Robert R. Gillies, Jiming Jin, Lawrence E. Hipps

Plants, Soils, and Climate Faculty Publications

The lake level elevation of the Great Salt Lake (GSL), a large closed basin lake in the arid western United States, is characterized by a pronounced quasi-decadal oscillation (QDO).The variation of the GSL elevation is very coherent with the QDO of sea surface temperature anomalies in the tropical central Pacific (also known as the Pacific QDO). However, such coherence denies any direct association between the precipitation in the GSL watershed and the Pacific QDO because, in a given frequency, the precipitation variation always leads the GSL elevation variation. Therefore, the precipitation variation is phase shifted from the Pacific QDO. This …

The Gravitational-Wave Memory Effect, Marc Favata

Department of Physics and Astronomy Faculty Scholarship and Creative Works

The nonlinear memory effect is a slowly growing, non-oscillatory contribution to the gravitational-wave amplitude. It originates from gravitational waves that are sourced by the previously emitted waves. In an ideal gravitational-wave interferometer a gravitational wave with memory causes a permanent displacement of the test masses that persists after the wave has passed. Surprisingly, the nonlinear memory affects the signal amplitude starting at leading (Newtonian-quadrupole) order. Despite this fact, the nonlinear memory is not easily extracted from current numerical relativity simulations. After reviewing the linear and nonlinear memory I summarize some recent work, including (1) computations of the memory contribution to …

Source Parameters And Time‐Dependent Slip Distributions Of Slow Slip Events On The Cascadia Subduction Zone From 1998 To 2008, D. A. Schmidt, Haiying Gao

Haiying Gao

We invert for the time‐dependent slip history of slow slip events on the Cascadia subduction zone using GPS data from 1998 to 2008. The 16 slip transients have sufficient station coverage to solve for the slip distribution on the plate interface. GPS time series are inverted for fault slip using the Extended Network Inversion Filter. Limited station coverage south of Portland (45.5°N latitude) restricts our analysis to events on the northern half of the subduction zone. Slip is resolved at the base of the seismogenic zone and the slip distributions suggest a potential segment boundary near Seattle (47.6°N) that correlates …

On Theconsistency Of Model, Ground-Based And Satellite Observations Of Tidal Signatures: Initial Results From Thecawses Tidal Campaigns, W. E. Ward, J. Oberheide, L. P. Goncharenko, T. Nakamura, P. Hoffmann, W. Singer, L. C. Chang, J. Du, D. Y. Wang, P. Batista, B. Clemesha, A. H. Manson, D. M. Riggin, C. Y. She, T. Tsuda, Tao Yuan

All Physics Faculty Publications

Comparisons between tidal wind signatures diagnosed from satellite and ground-based observations and a general circulations model for two (September–October 2005, March–April 2007) of the four Climate and Weather of the Sun-Earth System (CAWSES) Global Tidal Campaign observation periods are presented (CAWSES is an international program sponsored by Scientific Committee on Solar-Terrestrial Physics). Specific comparisons are made between model (extended Canadian Middle Atmosphere Model), satellite (Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED)), meteor, MF and incoherent scatter radar (ISR), and lidar tidal signatures in the mesosphere and lower thermosphere. The satellite and ground-based signatures are in good agreement and demonstrate for …

Information Security Among Small Organizations: A Survey, Jason Carter

Regis University Student Publications (comprehensive collection)

Small businesses are at extreme risk from network based attacks. A lack of security budget for hardware such as firewalls, intrusion detection systems, proxy servers, and web 2.0 gateway filters, plus a lack of technical expertise in network security, put small businesses at higher risk than larger companies. This paper researches the current state of small business network security and the types of threats they are seeing. It also looks at the factors that determine when and why security is implemented or modified.

Nonlinear Photoacoustics For Measuring The Nonlinear Optical Absorption Coefficient, Chandra S. Yelleswarapu, Sri-Rajasekhar Kothapalli

Physics Faculty Publications

We report a novel photoacoustic Z-scan (PAZ-scan) technique that combines the advantages offered by the conventional Z-scan method and the sensitivity of the photoacoustic detection. The sample is scanned through the focused laser beam and the generated photoacoustic signal is recorded using a 10 MHz focused ultrasound transducer. Since the signal strength is directly proportional to the optical absorption, PAZ-scan displays nonlinear behavior depicting the nonlinear optical absorption of the material. Among many advantages, our experiments on mouse blood show that PAZ-scan can potentially be used as a standard technique to calibrate contrast agents used in theranostics in general and …

Baseline Rockfall Rates And Rockfall Protection In Virginia, Brian Bruckno

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Current approaches to rockfall hazard and risk mitigation have been dominated by a model in which rockfall is treated as a global slope stability phenomenon which is mainly triggered by precipitation, freeze-thaw, or root wedging. The methods implemented by many public agencies and private entities developed from this conceptualization. These methods, such as the Rockfall Hazard Rating System, Key Block and Key Group Analysis, and remote sensing using LIDAR or digital images, are best applied to the end-members of slopes, such as pure engineered soil or structurally simple and consistent rock slopes. Slopes exhibiting complex structure, slopes that cross formations …

Utilizing The Integrated Difference Of Two Survival Functions To Quantify The Treatment Contrast For Designing, Monitoring And Analyzing A Comparative Clinical Study, Lihui Zhao, Lu Tian, Hajime Uno, Scott D. Solomon, Marc A. Pfeffer, J. S. Schindler, L. J. Wei

Harvard University Biostatistics Working Paper Series

No abstract provided.

Mathematical Modeling Of Optimal Seasonal Reproductive Strategies And A Comparison Of Long-Term Viabilities Of Annuals And Perennials, Anthony Delegge

Department of Mathematics: Dissertations, Theses, and Student Research

In 1954, Lamont Cole posed a question which has motivated much ecological work in the past 50 years: When is the life history strategy of semelparity (organisms reproduce once, then die) favored, via evolution, over iteroparity (organisms may reproduce multiple times in their lifetime)? Although common sense should dictate that iteroparity would always be favored, we can observe that this is not always the case, since annual plants are not only prevalent, but can dominate an area. Also, certain plant species may be perennial in one region, but annual in another. Thus, in these areas, certain characteristics must be present …

Ribosomal Rna Mutations That Inhibit The Activity Of Transfer-Messenger Rna Of Stalled Ribosomes, Jacob N. Crandall

Theses and Dissertations

In eubacteria, stalled ribosomes are rescued by a conserved quality-control mechanism involving transfer-messenger RNA (tmRNA) and its protein partner SmpB. Mimicking a tRNA, tmRNA enters stalled ribosomes, adds Ala to the nascent polypeptide, and serves as a template to encode a short peptide that tags the nascent protein for destruction. To further characterize the tagging process, we developed two genetic selections that link tmRNA activity to cell death. These negative selections can be used to identify inhibitors of tagging or to identify mutations in key residues essential for ribosome rescue. Little is known about which ribosomal elements are specifically required …

Big Macs And Eigenfactor Scores: Don't Let The Correlation Coefficients Fool You, Jevin D. West, Carl T. Bergstrom, Theodore C. Bergstrom

Ted C Bergstrom

A recent article by Phil Davis suggested that the Eigenvalue metric does adds little useful information to the more simply calculated measure of total citations published by the ISI. This paper argues that Davis's claim is an instance of a classic statistical fallacy of spurious correlation. Based on an analysis of the entire 2006 ISI Journal Citation Reports, we show that there are statistically and economically significant differences between the Eigenfactor metrics and the ISI's impact factor and total citations.

Remote Plasma Assisted Growth Of Graphene Films, Gopichand Nandamuri, Sergei Rouvimov, Raj Solanki

Physics Faculty Publications and Presentations

Single and multiple layers of graphene films were grown on 111 oriented single crystals of nickel and polycrystalline nickel films using remote plasma assisted chemical vapor deposition. Remote plasma was employed to eliminate the effect of the plasma electrical field on the orientation of the grown graphene films, as well as to reduce the growth temperature compared to conventional chemical vapor deposition. The electrical and optical properties, including high resolution transmission electron microscopy of these films, suggest that this approach is both versatile and scalable for potential large area optoelectronic applications.

New Chiral Phosphoramidite Complexes Of Iron As Catalytic Precursors In The Oxidation Of Activated Methylene Groups, Pushkar Shejwalkar, Nigam Rath, Eike Bauer

Chemistry & Biochemistry Faculty Works

New phosphoramidite complexes of iron were synthesized and structurally characterized. Reaction of the known chiral phosphoramidites (RO)2PNR’2 (R = binaphthyl, R’ = CH3, 1a; R = binaphthyl, R’ = benzyl, 1b) with [FeBr(Cp)(CO)2] afforded the title compounds [FeBr(Cp)(CO)(1a,b)] (4a,b) in 34 and 65 % isolated yields as mixtures of diastereomers, since both the metal and the ligand are stereogenic. Similarly, reaction of 1b with [Fe(Cp)I(CO)2] in the presence of catalytic [Fe(Cp)(CO)2]2 afforded [Fe(Cp)I(CO)(1b)] (5b) in 81% yield as a mixture of diastereomers. The molecular structures of 4a, 4b and 5 were determined, revealing a pseudo octahedral coordination geometry about the …

New Chiral Phosphoramidite Complexes Of Iron As Catalytic Precursors In The Oxidation Of Activated Methylene Groups, Pushkar Shejwalkar, Nigam P. Rath, Eike B. Bauer

Nigam Rath

Macrocyclic Pendant Arm Extension: An Application Of The Husigen 1,3-Dipolar Cycloaddition Reaction, Cory Kline, Rebecca Roesner, Faculty Advisor

John Wesley Powell Student Research Conference

No abstract provided.

Synthesis Of Polyazamacrocycle Molecular Tweezers As A Host For Polyoxoanions, Marie Sutor, Ronald Grider, Rebecca Roesner, Faculty Advisor

John Wesley Powell Student Research Conference

No abstract provided.

The Happy Marriage Between Laser And Supersonic Expansion, Timothy Zwier, M. G. Mellon Distinguished Professor Of Chemistry

John Wesley Powell Student Research Conference

No abstract provided.

M-Refinable Extensions Of Real Valued Functions, John Meuser, Tian-Xiao He, Faculty Advisor

John Wesley Powell Student Research Conference

No abstract provided.

Cadmium, Copper, Iron, And Zinc Concentrations In The Kidneys Of Grey Wolves (Canis Lupus) From Alaska, Idaho, Montana, And The Northwest Territories, Susan Blunck, Emily Jones, Kelly Petersen, Given Harper, Facutly Advisor, Jeffrey Frick, Faculty Advisor

John Wesley Powell Student Research Conference

No abstract provided.

An Implementation Of A Path Planning Algorithm For A Robot, Maia Czwornog, Joshua Brown Kramer, Faculty Advisor

John Wesley Powell Student Research Conference

No abstract provided.

Improving Data Filtering With Aztec Group, Jesse Schaar, Thushara Perera, Faculty Advisor

John Wesley Powell Student Research Conference

No abstract provided.

Optimization And Analysis Of A Robotic Navigational Algorithm, Derek Carlson, Joshua Brown Kramer, Faculty Advisor

John Wesley Powell Student Research Conference

The problem of robot navigation involves planning a path to move a robot from a start point to a known target point within an obstacle course. The efficiency of such an algorithm can be measured in several ways. For instance, Lumelsky and Stepanov measure the length of the path taken in terms of obstacle perimeters. Gabriely and Rimon compare their two-dimensional algorithm's efficiency to that of the optimal algorithm. Brown Kramer and Sabalka expand upon the work of Gabriely and Rimon to produce an algorithm for dimensions greater than two. The primary objective of this research was to implement improvements …

Synthesis Of A Thirty Member Macrocycle For Use In Host-Guest Chemistry, Keith A. Lehuta, Rebecca Roesner, Faculty Advisor

John Wesley Powell Student Research Conference

No abstract provided.

Development Of A Discovery Laboratory To Observe And Quantify Protein Denaturation And Coagulation In Egg White Albumin, Elizabeth Ave Maria, Melinda Baur, Faculty Advisor

John Wesley Powell Student Research Conference

No abstract provided.

Electrochemical Etching Technique For Fabricating Tungsten Nanotips, Thomas Bersano, Bruno Deharak, Faculty Advisor

John Wesley Powell Student Research Conference

No abstract provided.

The Synthesis Of A Cyclic Peptide Library For The Discovery Of Sickle-Cell Hemoglobin Ligands, Jeremy Henle, Brian Brennnan, Faculty Advisor

John Wesley Powell Student Research Conference

No abstract provided.

Electrochemical Assay Of Specific Biological Compounds Using Scanning Electrochemical Microscopy, Thomas Marlow, Aaron Moore, Melinda Baur, Faculty Advisor

John Wesley Powell Student Research Conference

No abstract provided.

Imaging The Topography And Monitoring The Electrochemical Activity Of Biological Samples, Erica Woodall, Emma Dewalt, Faculty Advisor, Melinda Baur, Faculty Advisor

John Wesley Powell Student Research Conference

No abstract provided.

Complete 2010 Program

John Wesley Powell Student Research Conference

No abstract provided.