Physical Sciences and Mathematics Commons^™

Discovery Of Photospheric Calcium Line-Strength Variations In The Dazd White Dwarf G29-38, Ted Von Hippel, Susan E. Thompson

Publications

Metals in the photospheres of white dwarfs with T_eff between 12,000 and 25,000 K should gravitationally settle out of these atmospheres in 1 ̶ 2 weeks. Temporal variations in the line strengths of these metals could provide a direct measurement of episodic metal accretion. Using archival VLT and Keck spectroscopy, we find evidence that the DAZd white dwarf G29-38 shows significant changes in its Ca _П K line strength. At the two best-observed epochs, we find that the Ca line equivalent width (EW) = 165 ̶ 4 mǺ (in 1996.885) and 280 ± 8 mǺ (in 1999.653), which is …

Depleted Carbon Monoxide In Fragment C Of The Jupiter-Family Comet 73p/Schwassmann-Wachmann 3, M. A. Disanti, W. M. Anderson, G. L. Villanueva, B. P. Bonev, K. Magee-Sauer, E. L. Gibb, M. J. Mumma

Erika Gibb

Sea Surface Pco2‐Sst Relationships Across A Cold‐Core Cyclonic Eddy: Implications For Understanding Regional Variability And Air‐Sea Gas Exchange, Feizhou Chen, Wei‐Jun Cai, Claudia R. Benitez-Nelson, Yongchen Wang

Faculty Publications

[1] This study is designed to improve the understanding of how biologically productive, cold‐core cyclonic eddies affect sea surface pCO2 in the lee of the main Hawaiian Islands in the subtropical North Pacific Gyre. We identified three unique relationships between pCO2 and sea surface temperature (SST). A positive correlation between pCO2 and SST was observed in the waters surrounding the eddy suggesting surface CO2 is controlled primarily by thermodynamics. In contrast, a negative relationship was observed within the eddy core as a result of the upwelling of CO2‐enriched subsurface waters. A third relationship existed throughout the rest …

Bayesian Bivariate Image Analysis With Application To Dual Autoradiography, Timothy D. Johnson, Morand Piert

The University of Michigan Department of Biostatistics Working Paper Series

We present a Bayesian bivariate image model and apply it to a study that was designed to investigate the relationship between hypoxia and angiogenesis in an animal tumor model. Two radiolabeled tracers (one measuring angio- genesis, the other measuring hypoxia) were simultaneously injected into the animals, the tumors removed and autoradiographic images of the tracer concentrations were obtained. We model correlation between tracers with a mixture of bivariate normal distributions and the spatial correlation inherent in the images by means of the celebrated Potts model. Although the Potts model is typically used for image segmentation, we use it solely as …

Superoxide Does React With Peroxides: Direct Observation Of The Haber-Weiss Reaction In The Gas Phase, Stephen J. Blanksby, G. B. Ellison, V. M. Bierbaum, S. Kato

Faculty of Science - Papers (Archive)

Reactions of superoxide with hydrogen peroxide and organic hydroperoxides are observed as efficient processes in the gas phase and yield products – including the ozonide anion – that are consistent with the one-electron reduction of the peroxide.

On The Accuracy Of Decentralized Virtual Coordinate Systems In Adversarial Networks, David Zage, Cristina Nita-Rotaru

Department of Computer Science Technical Reports

No abstract provided.

A Hierarchical Analysis Of Habitat Selection By Raccoons In Northern Indiana, James C. Beasley, Travis L. Devault, Monica I. Retamosa, Olin E. Rhodes Jr.

United States Department of Agriculture Wildlife Services: Staff Publications

Although numerous studies have examined habitat use by raccoons (Procyon lotor), information regarding seasonal habitat selection related to resource availability in agricultural landscapes is lacking for this species. Additionally, few studies using radiotelemetry have investigated habitat selection at multiple spatial scales or core-use areas by raccoons. We examined seasonal habitat selection of 55 (31 M, 24 F) adult raccoons at 3 hierarchical orders defined by the movement behavior of this species (second-order home range, second-order core-use area, and third-order home range) in northern Indiana, USA, from May 2003 to June 2005. Using compositional analysis, we assessed whether habitat …

Comparative Patterns Of Predation By Cougars And Recolonizing Wolves In Montana’S Madison Range, Todd C. Atwood, Eric M. Gese, Kyran E. Kunkel

United States Department of Agriculture Wildlife Services: Staff Publications

Numerous studies have documented how prey may use antipredator strategies to reduce the risk of predation from a single predator. However, when a recolonizing predator enters an already complex predator–prey system, specific antipredator behaviors may conflict and avoidance of one predator may enhance vulnerability to another. We studied the patterns of prey selection by recolonizing wolves (Canis lupus) and cougars (Puma concolor) in response to prey resource selection in the northern Madison Range, Montana, USA. Elk (Cervus elaphus) were the primary prey for wolves, and mule deer (Odocoileus hemionus) were the primary …

Stress Response Of Working African Elephants To Transportation And Safari Adventures, Joshua J. Millspaugh, Tarryne Burke, Gus Van Dyk, Rob Slotow, Brian E. Washburn, Rami J. Woods

United States Department of Agriculture Wildlife Services: Staff Publications

African elephants (Loxodonta africana) are intensively managed in southern Africa and are routinely translocated between reserves. Domesticated elephants are used for elephant-back safaris and interactions with guests. Understanding how elephants respond to such activities is critical because of welfare issues associated with both humans and elephants. We investigated the stress response (i.e., fecal glucocorticoid metabolite secretion [FGM]) of working elephants in Letsatsing Game Reserve, South Africa, over 1 year to evaluate their response to transportation and ecotourism activities. We used free-ranging elephants in adjacent Pilanesburg National Park as controls. Fecal glucocorticoid metabolites were greatest prior to and during …

Interview With Emil Slowinski, Dewitt Wallace Professor Of Chemistry, Emil Slowinski

Chemistry Department Oral Histories

No abstract provided.

Dynamical Control Of Electron Spin Coherence In A Quantum Dot: A Theoretical Study, Wenxian Zhang, V. V. Dobrovitski, Lea F. Santos, Lorenza Viola, B. N. Harmon

Dartmouth Scholarship

We investigate the performance of dynamical decoupling methods at suppressing electron spin decoherence from a low-temperature nuclear spin reservoir in a quantum dot. The controlled dynamics is studied through exact numerical simulation, with emphasis on realistic pulse delays and the long-time limit. Our results show that optimal performance for this system is attained by a periodic protocol exploiting concatenated design, with control rates substantially slower than expected from the upper spectral cutoff of the bath. For a known initial electron spin state, coherence can saturate at long times, signaling the creation of a stable “spin-locked” decoherence-free subspace. Analytical insight into …

Seasonal Variations Of The Vertical Fluxes Of Heat And Horizontal Momentum In The Mesopause Region At Starfire Optical Range, New Mexico, Chester S. Gardner, Alan Z. Liu

Physical Sciences - Daytona Beach

Lidar observations of wind and temperature profiles between 85 and 100 km, conducted at the Starfire Optical Range (SOR), New Mexico, are used to characterize the seasonal variations of the vertical fluxes of heat and horizontal momentum and their relationships to gravity wave activity in this region. The wind and temperature variances exhibit strong 6-month oscillations with maxima during the summer and winter that are about 3 times larger than the spring and fall minima. The vertical heat flux also exhibits strong 6-month oscillations with maximum downward flux during winter and summer. The downward heat flux peaks near 88 km …

The Non-Timber Forest Products Sector In Nepal : Policy Issues In Plant Conservation And Utilization, Ranju Shresthal Acharya

FIU Electronic Theses and Dissertations

The non-timber forest products (NTFPs) sector in Nepal is being promoted with the concept of sustainable management as articulated by the Convention on Biological Diversity. To promote and regulate this sector, Nepal adopted the Herbs and NTFP Development Policy in 2004. The goal of this thesis was to assess the effectiveness of this policy along with other forestry and natural resource policies in Nepal concerning the conservation and sustainable use of NTFPs. I conducted open-ended semi-structured interviews with 28 key informants in summer 2006 in Nepal where I also collected relevant documents and publications. I did qualitative analysis of data …

A Qualitative Analysis Of Hybrid Control Systems, Anca Georgeta Williams

Dissertations and Theses

Hybrid Control Systems are increasingly investigated as models for control systems where the interaction between continuous and discrete processes is tightly integrated. As yet, there is no general agreement as to what constitutes a canonical hybrid system. Rather various subclasses of systems combining continuous evolution and discrete event characteristics are analyzed for each application. In this dissertation we first unify the presentation of hybrid systems with a rich model which encompasses most examples of interest. We classify the available results and show how they fit together within the different subcategories. In the main part of the dissertation we prove that …

Utilizing Thermal Testing For Recovering, James Preciado, Thomas Werne

Mathematical Sciences Technical Reports (MSTR)

Given a two-dimensional region that contains one or more circular voids, we develop mathematical methods to locate the center and radius of the voids based on thermal boundary data. These methods can be readily applied in the field of non-destructive evaluation.

Human Frataxin: Iron And Ferrochelatase Binding Surface, Krisztina Z. Bencze, Taejin Yoon, CéSar MilláN-Pacheco, Patrick B. Bradley, Nina Pastor, J. A. Cowan, Timothy L. Stemmler

Biochemistry and Molecular Biology Faculty Publications

The coordinated iron structure and ferrochelatase binding surface of human frataxin have been characterized to provide insight into the protein’s ability to serve as the iron chaperone during heme biosynthesis.

Organosilicas With Chiral Bridges And Self-Generating Mesoporosity, Andreas Ide, Rebecca Voss, Gudrun Scholz, Geoffrey A. Ozin, Markus Antonietti, Arne Thomas

Rebecca Cademartiri

Amine-functionalized, chiral mesoporous organosilicas were prepared from a rationally designed precursor, which combines the functions of a network builder, a chiral latent functional group, and a porogen in one molecule. The precursors are formed by a convenient enantioselective hydroboration using (S)-monoisopinocampheylborane on an ethylene-bridged silica precursor. These precursors do self-organize when hydrolysis of their inorganic moiety takes place via an aggregation of their organic moiety into hydrophobic domains. After a condensation−ammonolysis sequence mesoporous organosilicas functionalized with chiral amine groups are obtained, with the complete chiral functionalities located at the pore wall surface and therefore accessible to chemical processes. The pore …

1,4-Di-9-Anthrylbutane, Mustafa Arslan, Erol Asker, John Masnovi, Ronald J. Baker

Chemistry Faculty Publications

In the title compound, C₃₂H₂₆, the molecule has an inversion centre at the mid-point of the central C—C bond. Weak intermolecular C—H...π interactions help to stabilize the crystal structure.

Mountain Beaver: A Primitive Fossorial Rodent, Wendy M. Arjo

United States Department of Agriculture Wildlife Services: Staff Publications

As the largest mammalian order, rodents are nearly cosmopolitan in distribution, can exploit a broad spectrum of foods, and can often reach high population densities. One sole representative of the most primitive family of rodents, Aplodontidae, does not share some of these common rodent characteristics. The aplodontoid rodents in the family Aplodontidae and Mylagsulidae radiated during the Miocene from the Allomyinae family (Carraway and Verts 1993). The extinct Mylagaulidae represents the earlier radiation of these rodents who exhibited great specialization (Carraway and Verts 1993). Unlike the other members of the rodent order, mountain beavers are not prolific breeders; nor are …

Subterranean Rodents As Pests: The Case Of The Pocket Gopher, Gary W. Witmer, Richard M. Engeman

United States Department of Agriculture Wildlife Services: Staff Publications

With over 2000 species, the order Rodentia has more members than any other order of mammals (Nowak 1999). The distribution of rodents is nearly worldwide; their use of habitats is extensive and varied. Most rodent species are relatively small, secretive, prolific, and all have continuously growing incisors. Many rodent species have ecological, scientific, cultural, and/or economic importance.

A variety of economic and health problems result from rodent interactions with humans. These include damage to growing crops, trees, seeds, pastures; damage and contamination of stored foods; damage to structures and property; and disease transmission (Witmer et al. 1995a). Singleton et al. …

Spin Blockade At Semiconductor/Ferromagnet Junctions, Yuriy V. Pershin Dr, Massimiliano Di Ventra

Faculty Publications

We study theoretically extraction of spin-polarized electrons at nonmagnetic semiconductor/ferromagnet junctions. The outflow of majority-spin electrons from the semiconductor into the ferromagnet leaves a cloud of minority-spin electrons in the semiconductor region near the junction, forming a local spin-dipole configuration at the semiconductor/ferromagnet interface. This minority-spin cloud can limit the majority-spin current through the junction, creating a pronounced spin blockade at a critical current. We calculate the critical spin-blockade current in both planar and cylindrical geometries and discuss possible experimental tests of our predictions.

A Study Of Different Decoders For The New Rotation Spreading Matrix For Block Spread Ofdm In Uwb Channels, Ibrahim S. Raad, Xiaojing Huang, Darryn Lowe

Faculty of Informatics - Papers (Archive)

This paper presents a study into different decoders for the new Rotation Spreading Matrix proposed for Block Spread OFDM (BSOFDM). It presents simulation results for the Maximum Likelihood (ML), Minimum Mean Square Error (MMSE), Zero Forcing (ZF), Maximal Ratio Combining (MRC) and Equal Gain Combining (EGC) decoders across the four IEEE defined Ultra-Wideband (UWB) channels CM1 to CM4. While it is well known that the ML decoder should theoretically outperform all the other decoders, practically due to its complexity it is not a viable option. It can be shown that MMSE, for BSOFDM with the proposed new Rotation Spreading Matrix, …

Higher Order Rotation Spreading Matrix For Block Spread Ofdm, Ibrahim S. Raad, Xiaojing Huang, Darryn Lowe

Faculty of Informatics - Papers (Archive)

This paper continues the work on the new Rotation matrix developed for BSOFDM which showed improvement in frequency selective channels such as the UWB IEEE defined CM1 to CM4 and overall system performance. This paper presents a method by which higher order Rotation matrix can be derived and simulation results are used to show that the higher order Rotation matrix outperforms the Hadamard matrix in frequency selective channels.

Computer Modeling And Visualization Of Luminescent Crystals: The Role Of Energy Transfer And Upconversion, Christopher S. Stuetzle

Computer Science Faculty Publications

No abstract provided.

A Tandem Enol Silane Formation-Mukaiyama Aldol Reaction Mediated By Tmsotf, C. Wade Downey, Miles W. Johnson

Chemistry Faculty Publications

A slight excess of silyl trifluoromethanesulfonate mediates a tandem enol silane formation-Mukaiyama aldol reaction in the presence of Hunig’s base. Preformation of the enol silane is unnecessary for efficient reactions, which proceed in 75–97% yield for the addition of aryl methyl ketones and acetate esters to non-enolizable aldehydes. Mechanistic data suggests that free amine is crucial for full conversion.

Presentation To Senior Leadership The Center For Academic Enrichment And Outreach, Public Lands Institute

Presentations (PLI)

• Strengthen the national fabric in support of public lands.
• Provide people of all ages with opportunities to participate in the enjoyment, protection, and responsible use of our public lands.
• Engage and inspire people to actively participate in the enjoyment, protection and responsible use of our public lands.
• Create high-quality, relevant, up-to-date knowledge to solve problems and make effective decisions about public lands.

Estimating The Effect Of Vigorous Physical Activity On Mortality In The Elderly Based On Realistic Individualized Treatment And Intention-To-Treat Rules, Oliver Bembom, Mark J. Van Der Laan

U.C. Berkeley Division of Biostatistics Working Paper Series

The effect of vigorous physical activity on mortality in the elderly is difficult to estimate using conventional approaches to causal inference that define this effect by comparing the mortality risks corresponding to hypothetical scenarios in which all subjects in the target population engage in a given level of vigorous physical activity. A causal effect defined on the basis of such a static treatment intervention can only be identified from observed data if all subjects in the target population have a positive probability of selecting each of the candidate treatment options, an assumption that is highly unrealistic in this case since …

This Message Will Self-Destruct: Self-Easing Covert Communication, Mikhail J. Atallah, Mercan Topkara, Umut Topkara

Department of Computer Science Technical Reports

No abstract provided.

Evaluating The Roc Performance Of Markers For Future Events, Margaret Pepe, Yingye Zheng, Yuying Jin

UW Biostatistics Working Paper Series

Receiver operating characteristic (ROC) curves play a central role in the evaluation of biomarkers and tests for disease diagnosis. Predictors for event time outcomes can also be evaluated with ROC curves, but the time lag between marker measurement and event time must be acknowledged. We discuss different definitions of time-dependent ROC curves in the context of real applications. Several approaches have been proposed for estimation. We contrast retrospective versus prospective methods in regards to assumptions and flexibility, including their capacities to incorporate censored data, competing risks and different sampling schemes. Applications to two datasets are presented.

The Shape Of Galaxy Cluster Dark Matter Haloes: Systematics Of Its Imprint On Cluster Gas And Comparison To Observations, Ricardo Flores, Brandon Allgood, Andrey Kravtsov, Joel Primack, David Buote, James Bullock

Physics Faculty Works

We study predictions for galaxy cluster observables that can test the statistics of dark matter halo shapes expected in a flat Λ cold dark matter (CDM) universe. We present a simple analytical model for the prediction of cluster-scale X-ray observations, approximating clusters as isothermal systems in hydrostatic equilibrium, and dark matter haloes as ellipsoids with uniform axial ratios (homeoidal ellipsoids). We test the model against high-resolution, hydrodynamic cluster simulations to gauge its reliability. We find that this simple prescription does a good job of predicting cluster X-ray ellipticities compared to the simulations as long as one focuses on cluster regions …