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Pt-Symmetric Acoustics, Xuefeng Zhu, Hamidreza Ramezani, Chengzhi Shi, Jie Zhu, Xiang Zhang

Physics & Astronomy Faculty Publications

We introduce here the concept of acoustic parity-time (PT) symmetry and demonstrate the extraordinary scattering characteristics of the acoustic PT medium. On the basis of exact calculations, we show how an acoustic PT -symmetric medium can become unidirectionally transparent at given frequencies. Combining such a PT -symmetric medium with transformation acoustics, we design two-dimensional symmetric acoustic cloaks that are unidirectionally invisible in a prescribed direction. Our results open new possibilities for designing functional acoustic devices with directional responses.

Unidirectional Lasing Emerging From Frozen Light In Nonreciprocal Cavities, Hamidreza Ramezani, S. Kalish, I. Vitebskiy, T. Kottos

Physics & Astronomy Faculty Publications

We introduce a class of unidirectional lasing modes associated with the frozen mode regime of nonreciprocal slow-wave structures. Such asymmetric modes can only exist in cavities with broken timereversal and space inversion symmetries. Their lasing frequency coincides with a spectral stationary inflection point of the underlying passive structure and is virtually independent of its size. These unidirectional lasers can be indispensable components of photonic integrated circuitry.

Search For Gravitational Radiation From Intermediate Mass Black Hole Binaries In Data From The Second Ligo-Virgo Joint Science Run, J. Aasi, B. P. Abbott, H. Daveloza, S. R. Morriss, Soma Mukherjee, M. E. Normandin, O. Puncken, Volker Quetschke, Malik Rakhmanov, K. E. Ramirez, Robert Stone, Cristina V. Torres, G. Valdes

Physics & Astronomy Faculty Publications

This paper reports on an unmodeled, all-sky search for gravitational waves from merging intermediate mass black hole binaries (IMBHB). The search was performed on data from the second joint science run of the LIGO and Virgo detectors (July 2009–October 2010) and was sensitive to IMBHBs with a range up to ∼200 Mpc, averaged over the possible sky positions and inclinations of the binaries with respect to the line of sight. No significant candidate was found. Upper limits on the coalescence-rate density of nonspinning IMBHBs with total masses between 100 and 450 M⊙ and mass ratios between 0.25 and 1 were …

Vanishing Power Lines And Emerging Distributed Generation, Gina S. Warren

Faculty Scholarship

Experts predict that distributed energy will contribute as much as twenty percent of the U.S. power supply by 2020. While no one will wake up tomorrow morning to an entirely new energy distribution system — complete with solar panels on the roof and a wind turbine in the back yard — distributed generation is receiving significant attention as the disruptive technology that will ultimately revolutionize the way energy is delivered in the United States. The reason for this shift is, in part, due to new technology that allows for more flexible localized generation of energy, and in part due to …

A Study Of Self-Concept In At-Risk Middle School Children Related To Behavior And Academic Performance, Tara Wade Franklin

Electronic Theses and Dissertations

The purpose of this study was to explore the factors that are associated with the development of self-concept and how self-concept influences or interacts with academic performance and behavior. This research study asked two questions: (1) what assists in the development of self-concept, and (2) how does self-concept impact academic performance and behavior in at-risk middle school students? Using evidence-based research, parental involvement, gender, and ethnicity were selected as key factors associated with the development of self-concept in adolescence. This study proposed that students with high self-concept would have positive academic and behavioral performance. Consequently, students with low self-concept would …

Collision And Diffusion In Microwave Breakdown Of Nitrogen Gas In And Around Microgaps, J. D. Campbell, A. Bowman Iii, G. T. Lenters, Stephen K. Remillard

Faculty Publications

The microwave induced breakdown of N-2 gas in microgaps was modeled using the collision frequency between electrons and neutral molecules and the effective electric field concept. Low pressure breakdown at the threshold electric field occurs outside the gap, but at high pressures it is found to occur inside the microgap with a large threshold breakdown electric field corresponding to a very large electron oscillation amplitude. Three distinct pressure regimes are apparent in the microgap breakdown: a low pressure multipactor branch, a mid-pressure Paschen branch, both of which occur in the space outside the microgap, and a high pressure diffusion-drift branch, …

Investigation Of The Seasonal Variations Of Aerosol Physicochemical Properties And Their Impact On Cloud Condensation Nuclei Number Concentration, Timothy Logan

Theses and Dissertations

Aerosols are among the most complex yet widely studied components of the atmosphere not only due to the seasonal variability of their physical and chemical properties but also their effects on climate change. The three main aerosol types that are known to affect the physics and chemistry of the atmosphere are: mineral dust, anthropogenic pollution, and biomass burning aerosols. In order to understand how these aerosols affect the atmosphere, this dissertation addresses the following three scientific questions through a combination of surface and satellite observations:

SQ1: What are the seasonal and regional variations of aerosol physico-chemical properties at four selected …

Embedded Star Formation In S4g Galaxy Dust Lanes., Debra M. Elmegreen, Bruce G. Elmegreen, Santiago Erroz-Ferrer, Johan H. Knapen, Yaron Teich, Mark Popinchalk, E. Athanassoula, Albert Bosma, Sebastien Comeron, Yuri N. Efremov, Dimitri A. Gadotti, Armando Gil De Paz, Joannah L. Hinz, Luis C. Ho, Benne W. Holwerda, Taehyun Kim, Jarkko Laine, Eija Laurikainen, Karin Menendez-Delmestre, Trisha Mizusawa, Juan Carlos Munoz-Mateos, Michael W. Regan, Heikki Salo, Mark Seibert, Kartik Sheth

Faculty and Staff Scholarship

Star-forming regions that are visible at 3.6 μm and Hα but not in the u, g, r, i, z bands of the Sloan Digital Sky Survey are measured in five nearby spiral galaxies to find extinctions averaging ∼3.8 mag and stellar masses averaging ∼5 × 104 M. These regions are apparently young star complexes embedded in dark filamentary shock fronts connected with spiral arms. The associated cloud masses are ∼107 M. The conditions required to make such complexes are explored, including gravitational instabilities in spiral-shocked gas and compression of incident clouds. We find that instabilities are too slow for a …

Constraining The Age Of The Ngc 4565 Hi Disk Warp : Determining The Origin Of Gas Warps., David J. Radburn-Smith, Roelof S. De Jong, David Streich, Eric F. Bell, Julianne J. Dalcanton, Andrew E. Dolphin, Adrienne M. Stilp, Antonela Monachesi, Benne W. Holwerda, Jeremy Bailin

Faculty and Staff Scholarship

We have mapped the distribution of young and old stars in the gaseous H i warp of NGC 4565. We find a clear correlation of young stars (< 600 Myr) with the warp but no coincident old stars (> 1 Gyr), which places an upper limit on the age of the structure. The formation rate of the young stars, which increased ∼ 300 Myr ago relative to the surrounding regions, is (6.3+2.5 −1.5) × 10−5 M yr−1 kpc−2. This implies a ∼ 60 ± 20 Gyr depletion time of the H i warp, similar to the timescales calculated for the outer H i disks of nearby spiral galaxies. While some stars …

Ghosts I : A New Faint Very Isolated Dwarf Galaxy At D = 12 ± 2 Mpc., Antonela Monachesi, Eric F. Bell, David J. Radburn-Smith, Roelof S. De Jong, Jeremy Bailin, Julianne J. Dalcanton, Benne W. Holwerda, H. Alyson Ford, David Streich, Marija Vlajic, Daniel B. Zucker

Faculty and Staff Scholarship

We report the discovery of a new faint dwarf galaxy, GHOSTS I, using HST/ACS data from one of our GHOSTS (Galaxy Halos, Outer disks, Substructure, Thick disk, and Star clusters) fields. Its detected individual stars populate an approximately 1 mag range of its luminosity function (LF). Using synthetic color–magnitude diagrams (CMDs) to compare with the galaxy’s CMD, we find that the colors and magnitudes of GHOSTS I’s individual stars are most consistent with being young helium-burning and asymptotic giant branch stars at a distance of ∼12±2 Mpc. Morphologically, GHOSTS I appears to be actively forming stars, so we tentatively classify …

Morphological Parameters Of A Spitzer Survey Of Stellar Structure In Galaxies., Benne W. Holwerda, J. C. Munoz-Mateos, S. Comeron, S. Meidt, K. Sheth, S. Laine, J. L. Hinz, M. W. Regan, A. Gil De Paz, K. Menendez-Delmestre, M. Seibert, T. Kim, T. Mizusawa, E. Laurikainen, H. Salo, J. Laine, D. A. Gadotti, D. Zaritsky, S. Erroz-Ferrer, L. C. Ho, J. H. Knapen, E. Athanassoula, A. Bosma, N. Pirzkal

Faculty and Staff Scholarship

The morphology of galaxies can be quantified to some degree using a set of scale-invariant parameters. Concentration (C), asymmetry (A), smoothness (S), the Gini index (G), the relative contribution of the brightest pixels to the secondorder moment of the flux (M20), ellipticity (E), and the Gini index of the second-order moment (GM) have all been applied to morphologically classify galaxies at various wavelengths. Here, we present a catalog of these parameters for the Spitzer Survey of stellar structure in Galaxies, a volume-limited, near-infrared (NIR) imaging survey of nearby galaxies using the 3.6 and 4.5μm channels of the Infrared Array Camera …

A Program For Optical Observations Of Advanced Ligo Early Triggers In The Southern Hemisphere, Matthew Benacquista, Chris Belczynski, Martin Beroiz, Maria Branchesi, Carlos Colazo, Mario C. Diaz, Mancheno Dominguez, Diego Garcia Lambas, Shengnan Liang, Lucas M. Macri, Tania Peñuela

Physics & Astronomy Faculty Publications

In this poster we present a plan to follow-up optically early triggers from the Advanced LIGO gravitational wave detectors, which will start operating in scientific mode in the northern summer of 2015.

Gravity Effect On Electrical Field Generation And Charge Carriers Transfer During Combustion Synthesis Of Sulfides, A. A. Markov, I. A. Filimonov, Karen S. Martirosyan

Physics & Astronomy Faculty Publications

The effect of gravity on the electric potential generated by the combustion synthesis of zinc sulfide is analyzed using the numerical simulation. Recent experimental studies on generation of electric voltage during combustion synthesis of zinc sulfide (ZnS) have revealed high voltage signals (4 V) with duration about 1 s, which are much higher than those produced by the gas–solid and solid–solid combustion reactions studied previously. These data have raised the question about mechanism of such a phenomenon. In our previous work we developed a novel (distributed) model describing the electric potential generation during combustion synthesis of sulfides (CSS) that didn't …

Fabrication Of Yttrium Ferrite Nanoparticles By Solution Combustion Synthesis, A. A. Saukhimov, Mkhitar A. Hobosyan, Gamage C. Dannangoda, N. N. Zhumabekova, S. E. Kumekov

Physics & Astronomy Faculty Publications

The ternary oxide system Y-Fe-O presents fascinating magnetic properties that are sensitive to the crystalline size of particles. There is a major challenge to fabricate these materials in nano-crystalline forms due to particle conglomeration during nucleation and synthesis. In this paper we report the fabrication of nano sized crystalline yttrium ferrite by solution combustion synthesis (SCS) where yttrium and iron nitrates were used as metal precursors with glycine as a fuel. The magnetic properties of the product can be selectively controlled by adjusting the ratio of glycine to metal nitrates. Yttrium ferrite nano-powder was obtained by using three concentration of …

Free-Energy Calculations For Semi-Flexible Macromolecules: Applications To Dna Knotting And Looping, Stefan M. Giovan, Robert G. Scharein, Andreas Hanke, Stephen D. Levene

Physics & Astronomy Faculty Publications

We present a method to obtain numerically accurate values of configurational free energies of semiflexible macromolecular systems, based on the technique of thermodynamic integration combined with normal-mode analysis of a reference system subject to harmonic constraints. Compared with previous free-energy calculations that depend on a reference state, our approach introduces two innovations, namely, the use of internal coordinates to constrain the reference states and the ability to freely select these reference states. As a consequence, it is possible to explore systems that undergo substantially larger fluctuations than those considered in previous calculations, including semiflexible biopolymers having arbitrary ratios of contour …

Report To The Chicago Park District On Conflicts With Ring-Billed Gulls And The 2014 Integrated Ring-Billed Gull Damage Management Project, M. L. Bloomquist, J.W. Hartmann, T.G. Guerrant, S. F. Beckerman, R. M. Engeman

United States Department of Agriculture Wildlife Services: Staff Publications

The large ring-billed gull (Larus delawarensis) population in the City of Chicago has caused various conflicts including general nuisance, property damage, economic losses, and threats to human health and safety. Several studies have shown a relationship between ring-billed gulls and increased levels of fecal indicator bacteria (FIB) such as Escherichia coli (E. coli) in nearshore waters. Results of tests for E. coli have led to the issuance of swim advisories at Chicago beaches.

The objectives of the Chicago Ring-billed Gull Damage Management Project were to (1) reduce the local production of ring-billed gulls, (2) reduce the …

Predicted Wildlife Disease-Related Climate Change Impacts Of Specific Concern To Usda Aphis Wildlife Services, Timothy P. Algeo, Richard B. Chipman, Dennis Slate, Jerome E. Freier, Thomas J. Deliberto

United States Department of Agriculture Wildlife Services: Staff Publications

USDA APHISWildlife Services plans for and responds to a variety of exigencies such as wildlife hazards to aircraft, disease emergence from wildlife translocations, oral rabies vaccine barrier compromises, and extreme weather events. These are often collaborative efforts with state and federal agencies and others. Climate change based in part on fossil fuel use and methane gas emissions has predictable as well as unknown consequences. As a federal leader in wildlife disease research and management, it is incumbent upon Wildlife Services to be current with the scientific literature; assess potential impacts and wildlife disease management intervention needs from predicted climate change …

Managing California Ground Squirrels On Levees Using Habitat Modification, Dirk Van Vuren, Miguel A. Ordeñana, Michael C. Mcgrann, Are R. Berentsen

United States Department of Agriculture Wildlife Services: Staff Publications

Burrowing mammals such as ground squirrels are considered threats to levee integrity, and some authors have proposed that ground squirrel occurrence on levees might be reduced by habitat modification. We characterized the threat that California ground squirrels pose to levees by summarizing available information on burrow lengths and depths, and we reviewed available information about the efficacy of habitat modification to reduce squirrel occurrence on levees. Burrows of California ground squirrels averaged 8.2 m in length (range = 0.9-42.1 m) and 75 cm in greatest depth (range = 33-168 cm), indicating that most burrows are not long enough to transect …

Development Of Dietary-Based Toxicity Reference Values To Assess The Risk Of Chlorophacinone To Non-Target Raptorial Birds, Barnett A. Rattner, Rebecca S. Lazarus, Sandra L. Schultz, Katherine E. Horak, Benjamin G. Abbo, Steven F. Volker

United States Department of Agriculture Wildlife Services: Staff Publications

Regulatory changes in the use of some second-generation anticoagulant rodenticides in parts of North America may result in expanded use of first-generation anticoagulant rodenticides (FGARs). Recent toxicological studies with captive raptors have demonstrated that these species are considerably more sensitive to the FGAR diphacinone than traditional avian wildlife test species (mallard, bobwhite). We have now examined the toxicity of the FGAR chlorophacinone (CPN) to American kestrels fed rat tissue mechanically amended with CPN, or rat tissue containing biologically-incorporated CPN, for 7 days. Nominal CPN concentrations in these diets were 0.15, 0.75, and 1.5 μg/g food wet weight, and actual CPN …

Incorporating Cold-Air Pooling Into Downscaled Climate Models Increases Potential Refugia For Snow-Dependent Species Within The Sierra Nevada Ecoregion, Ca, Jennifer A. Curtis, Lorraine E. Flint, Alan L. Flint, Jessica D. Lundquist, Brian Hudgens, Erin E. Boydston, Julie K. Young

United States Department of Agriculture Wildlife Services: Staff Publications

We present a unique water-balance approach for modeling snowpack under historic, current and future climates throughout the Sierra Nevada Ecoregion. Our methodology uses a finer scale (270 m) than previous regional studies and incorporates cold-air pooling, an atmospheric process that sustains cooler temperatures in topographic depressions thereby mitigating snowmelt. Our results are intended to support management and conservation of snow-dependent species, which requires characterization of suitable habitat under current and future climates. We use the wolverine (Gulo gulo) as an example species and investigate potential habitat based on the depth and extent of spring snowpack within four National …

Russian Olive (Elaeagnus Angustifolia) Dispersal By European Starlings (Sturnus Vulgaris), Ryan J. Edwards, Larry C. Clark, K. George Beck

United States Department of Agriculture Wildlife Services: Staff Publications

Studies were conducted to document that European starlings consume Russian olive fruits and determine subsequent effects on seed germination. In the first study, avian feeding patterns at Russian olive trees were monitored over a 1-yr period using motion activated digital photography. Starlings fed on Russian olive fruits with highest activity occurring in November and December. In a second study, 20 captive European starlings were fed Russian olive fruits and seed germination rates were determined for three categories: consumed by starlings, hulled fruits (pericarp removed), and whole fruits. Starlings readily consumed Russian olive fruits and most seeds were regurgitated 30 min …

The Influence Of Breeding Experience On Nest Success In Red-Winged Blackbird, George M. Linz, Richard S. Sawin, Mark W. Lutman

United States Department of Agriculture Wildlife Services: Staff Publications

The Red-winged Blackbird (Agelaius phoeniceus) is a polygynous species, and females are typically responsible for the majority of parental care. Despite their limited involvement, males can contribute to reproduction through nest defense and the feeding of nestlings. Some aspects of nest defense may be learned, and older males are more likely to feed young, suggesting that males with previous breeding experience may enjoy higher nest success than their naïve counterparts. We manipulated territory ownership on 10 wetlands in central North Dakota in order to examine the influence of breeding experience on reproductive success. We found no evidence that …

Responses To Canopy Loss And Debris Deposition In A Tropical Forest Ecosystem: Synthesis From An Experimental Manipulation Simulating Effects Of Hurricane Disturbance, Aaron B. Shiels, Grizelle González, Michael R. Willig

United States Department of Agriculture Wildlife Services: Staff Publications

Hurricanes, cyclones, or typhoons are intense and broad-scale disturbances that affect many island and coastal ecosystems throughout the world. We summarize the findings of the articles that compose this special issue of Forest Ecology and Management, which focuses on a manipulative experiment (the Canopy Trimming Experiment, CTE) that simulates two key aspects of hurricane effects in a wet tropical forest. Although previous studies of tropical and subtropical forests have documented changes resulting from hurricanes, it is not clear which of the two simultaneously occurring direct effects of hurricanes—canopy openness or debris deposition—most influence responses. In the Luquillo Experimental Forest …

Trait-Based Plant Mortality And Preference For Native Versus Non-Native Seedlings By Invasive Slug And Snail Herbivores In Hawaii, Aaron B. Shiels, Martin K. Ennis, Laura Shiels

United States Department of Agriculture Wildlife Services: Staff Publications

Non-native herbivores may alter plant communities through their preferential consumption of seedlings of different species. We assessed seedling herbivory by two invasive gastropod species in Hawaii, the giant African snail (Achatina fulica) and the Cuban brown slug (Veronicella cubensis). We hypothesized that six native species would suffer greater gastropod herbivory than four non-native species, and that species with short stature, thin leaves, and lacking physical defenses would suffer the greatest mortality from gastropods. Herbivory was measured during 13-day preference trials using enclosures that each contained four different woody species (two native, two non-native) and were assigned …

Understory Fern Community Structure, Growth And Spore Production Responses To A Large-Scale Hurricane Experiment In A Puerto Rico Rainforest, Joanne M. Sharpe, Aaron B. Shiels

United States Department of Agriculture Wildlife Services: Staff Publications

Ferns are abundant in most rainforest understories yet their responses to hurricanes have not been wellstudied. Fern community structure, growth and spore production were monitored for two years before and five years after a large-scale experiment that simulated two key components of severe hurricane disturbance: canopy openness and debris deposition. The canopy was opened by cutting branches above 3 m and the fallen leaf and woody debris was either added to or removed from the forest floor resulting in four treatments that were replicated three times in a factorial design. Of the 16 fern species observed during the experiment 12 …

Efficacy Of Plastic Mesh Tubes In Reducing Herbivory Damage By The Invasive Nutria (Myocastor Coypus) In An Urban Restoration Site, Trevor R. Sheffels, Mark D. Sytsma, Jacoby Carter, Jimmy D. Taylor Ii

United States Department of Agriculture Wildlife Services: Staff Publications

The restoration of stream corridors is becoming an increasingly important component of urban landscape planning, and the high cost of these projects necessitates the need to understand and address potential ecological obstacles to project success. The nutria (Myocastor coypus) is an invasive, semi-aquatic rodent native to South America that causes detrimental ecological impacts in riparian and wetland habitats throughout its introduced range, and techniques are needed to reduce nutria herbivory damage to urban stream restoration projects. We assessed the efficacy of standard Vexar® plastic mesh tubes in reducing nutria herbivory damage to newly established woody plants. The study …

Prevalence And Diversity Of Babesia, Hepatozoon, Ehrlichia, And Bartonella In Wild And Domestic Carnivores From Zambia, Africa, Brianna M. Williams, Are Berentsen, Barbara C. Shock, Maria Teixiera, Michael R. Dunbar, Matthew S. Becker, Michael J. Yabsley

United States Department of Agriculture Wildlife Services: Staff Publications

A molecular survey was conducted for several hemoparasites of domestic dogs and three species of wild carnivores from two sites in Zambia. Three Babesia spp. were detected including Babesia felis and Babesia leo in lions (Panthera leo) and a Babesia sp. (similar to Babesia lengau) in spotted hyenas (Crocuta crocuta) and a single lion. All wild dogs (Lycaon pictus) and domestic dogs were negative for Babesia. High prevalences for Hepatozoon were noted in all three wild carnivores (38–61 %) and in domestic dogs (13 %). Significantly higher prevalences were noted in hyenas and …

Perceived Impacts Of Wild Turkeys And Management Techniques For Wisconsin Ginseng Production, Scott J. Werner, Stephanie A. Shwiff, Julie L. Elser, Katy N. Kirkpatrick, Susan E. Pettit, Jason Suckow, Robert C. Willging, Jim A. Tharman, Joe Heil

United States Department of Agriculture Wildlife Services: Staff Publications

The restoration of eastern wild turkeys (Meleagris gallopavo silvestris; Viellot) within Wisconsin has successfully populated the central counties which account for 95% of American ginseng (Panax quinquefolius L.) production. In response to perceived and emerging conflicts, the Ginseng Board of Wisconsin, Inc. conducted producer surveys in March 2006 and 2012 to determine the extent and timing of wild turkey damage experienced among all Wisconsin ginseng producers, and the methods used to minimize wild turkey damage. We summarized 47 and 63 completed surveys in 2006 and 2012, respectively. Most survey respondents reported that wild turkeys were present and …

Synergistic Effect Of An Ultraviolet Feeding Cue For An Avianrepellent And Protection Of Agricultural Crops, Scott J. Werner, Shelagh T. Deliberto, Susan E. Pettit, Anna M. Mangan

United States Department of Agriculture Wildlife Services: Staff Publications

Application strategies for avian repellents are needed to maintain efficacious repellentconcentrations throughout the period of needed crop protection. We investigated the repellency of an ultraviolet (UV) feeding cue in the absence of postingestive consequences, thecombination of the UV feeding cue and an UV-absorbent, postingestive repellent (i.e., arepellent that causes negative postingestive consequences), and a non-UV feeding cue com-bined with the UV-absorbent, postingestive repellent in red-winged blackbirds (Agelaiusphoeniceus). In the absence of negative postingestive consequences, 0.2% of the UV feed-ing cue (wt/wt) was not aversive relative to untreated food (i.e., baseline preference test; P = 0.1732). Relative to the …

Human–Osprey Conflicts: Industry, Utilities, Communication, And Transportation, Brian E. Washburn

United States Department of Agriculture Wildlife Services: Staff Publications

Although often perceived as a species of remote settings, Ospreys (Pandion haliaetus) are highly adaptable and currently are abundant in many urban and suburban landscapes. Living in close proximity to humans, Ospreys often come into conflict with people and several important issues require the attention of and management by natural resource professionals. These include effects on: (1) industry (e.g., foraging at aquaculture facilities), (2) utilities (e.g., nesting on electric utility power poles and transmission towers), (3) communication networks (e.g., nesting on cellular towers), and (4) transportation systems (e.g., risks posed to human health and safety due to Osprey–aircraft …