Physical Sciences and Mathematics Commons^™

A Stimulated Emission Study Of The Ground State Bending Levels Of Bh2 Through The Barrier To Linearity And Ab Initio Calculations Of Near-Spectroscopic Accuracy, Bing Jin, Dennis J. Clouthier, Riccardo Tarroni

Chemistry Faculty Publications

The ground state bending levels of ¹¹BH₂ have been studied experimentally using a combination of low-resolution emission spectroscopy and high-resolution stimulated emission pumping (SEP) measurements. The data encompass the energy range below, through, and above the calculated position of the barrier to linearity. For the bending levels (0,3,0) and above, the data show substantial K-reordering, with the K"_a = 1 levels falling well below those with K"_a = 0. A comparison of the high-resolution rotationally resolved SEP data to our own very high level ab initio calculations of the rovibronic energy levels shows agreement approaching …

The Influence Of Recurrent Modes Of Climate Variability On The Occurrence Of Monthly Temperature Extremes Over South America, Paul C. Loikith, Judah Detzer, Carlos R. Mechoso, Huikyo Lee, Armineh Barkhordarian

Geography Faculty Publications and Presentations

The associations between extreme temperature months and four prominent modes of recurrent climate variability are examined over South America. Associations are computed as the percent of extreme temperature months concurrent with the upper and lower quartiles of the El Niño–Southern Oscillation (ENSO), the Atlantic Niño, the Pacific Decadal Oscillation (PDO), and the Southern Annular Mode (SAM) index distributions, stratified by season. The relationship is strongest for ENSO, with nearly every extreme temperature month concurrent with the upper or lower quartiles of its distribution in portions of northwestern South America during some seasons. The likelihood of extreme warm temperatures is enhanced …

Vetcompass Australia: A National Big Data Collection System For Veterinary Science, Paul Mcgreevy, Peter Thomson, Navneet K. Dhand, David Raubenheimer, Sophie Masters, Caroline S. Mansfield, Timothy Baldwin, Ricardo J. Soares Magalhaes, Jacquie Rand, Peter Hill, Anne Peaston, James Gilkerson, Martin Combs, Shane Raidal, Peter Irwin, Peter Irons, Richard Squires, David Brodbelt, Jeremy Hammond

Paul McGreevy, PhD

Non-Hermitian Engineering Of Single Mode Two Dimensional Laser Arrays, M. H. Teimourpour, Li Ge, Demetrios N. Christodoulides, Ramy El-Ganainy

Ramy El-Ganainy

A new scheme for building two dimensional laser arrays that operate in the single supermode regime is proposed. This is done by introducing an optical coupling between the laser array and lossy pseudo-isospectral chains of photonic resonators. The spectrum of this discrete reservoir is tailored to suppress all the supermodes of the main array except the fundamental one. This spectral engineering is facilitated by employing the Householder transformation in conjunction with discrete supersymmetry. The proposed scheme is general and can in principle be used in different platforms such as VCSEL arrays and photonic crystal laser arrays.

Non-Hermitian Engineering Of Synthetic Saturable Absorbers For Applications In Photonics, M. H. Teimourpour, A. Rahman, K. Srinivasan, Ramy El-Ganainy

Ramy El-Ganainy

We explore a type of synthetic saturable absorber based on quantum-inspired photonic arrays. We demonstrate that the interplay between optical Kerr nonlinearity, interference effects, and non-Hermiticity through radiation loss leads to a nonlinear optical filtering response with two distinct regimes of small and large optical transmissions. More interestingly, we show that the boundary between these two regimes can be very sharp. The threshold optical intensity that marks this abrupt “phase transition” and its steepness can be engineered by varying the number of the guiding elements. The practical feasibility of these structures as well as their potential applications in laser systems …

Supersymetric Laser Arrays, Ramy El-Ganainy, Li Ge, M. Khajavikhan, Demetrios N. Christodoulides

Ramy El-Ganainy

We introduce the concept of supersymmetric laser arrays that consist of a main optical lattice and its superpartner structure, and we investigate the onset of their lasing oscillations. Due to the coupling of the two constituent lattices, their degenerate optical modes form doublets, while the extra mode associated with unbroken supersymmetry forms a singlet state. Singlet lasing can be achieved for a wide range of design parameters, either by introducing stronger loss in the partner lattice or by pumping only the main array. Our findings suggest the possibility of building single-mode, high-power laser arrays and are also important for understanding …

Topological Tight-Binding Models From Nontrivial Square Roots, J. Arkinstall, M. H. Teimourpour, L. Feng, Ramy El-Ganainy, H. Schomerus

Ramy El-Ganainy

We describe a versatile mechanism that provides tight-binding models with an enriched, topologically nontrivial band structure. The mechanism is algebraic in nature, and leads to tight-binding models that can be interpreted as a nontrivial square root of a parent lattice Hamiltonian—in analogy to the passage from a Klein-Gordon equation to a Dirac equation. In the tight-binding setting, the square-root operation admits to induce spectral symmetries at the expense of broken crystal symmetries. As we illustrate in detail for a simple one-dimensional example, the emergent and inherited spectral symmetries equip the energy gaps with independent topological quantum numbers that control the …

Food Habits And Anthropogenic Supplementation In Coyote Diets Along An Urban-Rural Gradient, Erica Santana, Jim Armstrong

Human–Wildlife Interactions

Coyotes are recent colonists of the Southeast and have broadened their niche to include exploitation of urban areas. The aim of this study was to examine diet of coyotes inhabiting areas of differential development by humans and assess prevalence of anthropogenic feeding, to detect a possible shift in dietary trends. In urban, exurban, and rural areas of east-central Alabama, 159 fecal samples were collected and examined to reconstruct the diet. Consumption of anthropogenic food did not vary significantly along an urban-rural gradient and foods consumed were similar among habitats. While results of this study can provide insight to guide decisions …

Sma Observations Of The Hot Molecular Core Iras 18566+0408, Andrea Silva, Qizhou Zhang, Patricio Sanhueza, Xing Lu, Maria T. Beltran, Cassandra Fallscheer, Henrik Beuther, T. K. Sridharan, Riccardo Cesaroni

All Faculty Scholarship for the College of the Sciences

We present Submillimeter Array (SMA) observations toward the high-mass star-forming region IRAS 18566+0408. Observations at the 1.3 mm continuum and in several molecular line transitions were performed in the compact (2ʺ4 angular resolution) and very-extended (~0ʺ4 angular resolution) configurations. The continuum emission from the compact configuration shows a dust core of 150 M _⊙, while the very-extended configuration reveals a dense (2.6 × 10⁷ cm⁻³) and compact (~4000 au) condensation of 8 M _⊙. We detect 31 molecular transitions from 14 species including CO isotopologues, SO, CH₃OH, OCS, and CH₃CN. Using …

Copper(Ii)- And Gold(Iii)-Mediated Cyclization Of A Thiourea To A Substituted 2-Aminobenzothiazole, Zachary W. Schroeder, L. K. Hiscock, Louise N. Dawe

Chemistry Faculty Publications

Benzothiazole derivatives are a class of privileged molecules due to their biological activity and pharmaceutical applications. One route to these molecules is via intramolecular cyclization of thioureas to form substituted 2-aminobenzothiazoles, but this often requires harsh conditions or employs expensive metal catalysts. Herein, the copper(II)- and gold(III)-mediated cyclizations of thioureas to substituted 2-aminobenzothiazoles are reported. The single-crystal X-ray structures of the thiourea N-(3-methoxyphenyl)-N'- (pyridin-2-yl)thiourea, C₁₃H₁₃N₃OS, and the intermediate metal complexes aquabis[5-methoxy-N-(pyridin-2-yl-κN)-1,3-benzothiazol-2-amine-κN³]copper(II) dinitrate, [Cu(C₁₃H₁₁N₃OS)₂(H₂O)](NO₃) …

Phase Behavior Of Binary And Polydisperse Suspensions Of Compressible Microgels Controlled By Selective Particle Deswelling, A. Scotti, U. Gasser, E. S. Herman, Jun Han, A. Menzel, L. Andrew Lyon, A. Fernandez-Nieves

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

We investigate the phase behavior of suspensions of poly(N-isopropylacrylamide) (pNIPAM) microgels with either bimodal or polydisperse size distribution. We observe a shift of the fluid-crystal transition to higher concentrations depending on the polydispersity or the fraction of large particles in suspension. Crystallization is observed up to polydispersities as high as 18.5%, and up to a number fraction of large particles of 29% in bidisperse suspensions. The crystal structure is random hexagonal close-packed as in monodisperse pNIPAM microgel suspensions.We explain our experimental results by considering the effect of bound counterions. Above a critical particle concentration, these cause deswelling of the largest …

Antihydrogen Accumulation For Fundamental Symmetry Tests, Timothy Tharp, M. Ahmadi, P. Nolan, P. Pusa, B. X. R. Alves, T. Friesen, C. O. Rasmussen, G. Stutter, C. J. Baker, M. Charlton, S. Eriksson, C. A. Isaac, S. A. Jones, N. Madsen, D. Maxwell, M. Sameed, D. P. Van Der Werf, W. Bertsche, M. A. Johnson, E. Butler, A. Capra, R. Collister, M. C. Fujiwara, L. Kurchaninov, J. T. K. Mckenna, J. M. Michan, K. Olchanski, A. Olin, C. Carruth, J. Fajans, J. S. Wurtele, C. L. Cesar, R. L. Sacramento, D. M. Silveira, S. Cohen, A. Evans, C. So, R. I. Thompson, N. Evetts, W. N. Hardy, T. Momose, A. Gutierrez, M. E. Hayden, J. J. Munich, A. Ishida, S. Jonsell, M. Mathers, S. Menary, J. E. Thompson, J.M. Michan, F. Robicheaux, E. Sarid, S. Stracha

Physics Faculty Research and Publications

Antihydrogen, a positron bound to an antiproton, is the simplest anti-atom. Its structure and properties are expected to mirror those of the hydrogen atom. Prospects for precision comparisons of the two, as tests of fundamental symmetries, are driving a vibrant programme of research. In this regard, a limiting factor in most experiments is the availability of large numbers of cold ground state antihydrogen atoms. Here, we describe how an improved synthesis process results in a maximum rate of 10.5 ± 0.6 atoms trapped and detected per cycle, corresponding to more than an order of magnitude improvement over previous work. Additionally, …

Distinct Ice Patterns On Solid Surfaces With Various Wettabilities, Jie Liu, Chongqin Zhu, Kai Liu, Ying Jiang, Yanlin Song, Joseph S. Francisco, Xiao Cheng Zeng, Jianjun Wang

Xiao Cheng Zeng Publications

No relationship has been established between surface wettability and ice growth patterns, although ice often forms on top of solid surfaces. Here, we report experimental observations obtained using a process specially designed to avoid the influence of nucleation and describe the wettability-dependent ice morphology on solid surfaces under atmospheric conditions and the discovery of two growth modes of ice crystals: along-surface and off-surface growth modes. Using atomistic molecular dynamics simulation analysis, we show that these distinct ice growth phenomena are attributable to the presence (or absence) of bilayer ice on solid surfaces with different wettability; that is, the formation of …

In Place: September 24, 2017, Place

PLACE Historical Documents

In PLACE is a newsletter designed to keep the Linfield College community apprised of information related to PLACE activities, as well as ways to bring the program into classes. Included in this issue:

• PLACE: What's In It for Faculty?
• PLACE: What's In It for Students?
• PLACE in the News
• Last Week in PLACE

The Double Pivot Simplex Method, Fabio Vitor, Todd Easton

Mathematics Faculty Publications

The simplex method, created by George Dantzig, optimally solves a linear program by pivoting. Dantzig’s pivots move from a basic feasible solution to a different basic feasible solution by exchanging exactly one basic variable with a nonbasic variable. This paper introduces the double pivot simplex method, which can transition between basic feasible solutions using two variables instead of one. Double pivots are performed by identifying the optimal basis in a two variable linear program using a new method called the slope algorithm. The slope algorithm is fast and allows an iteration of DPSM to have the same theoretical running time …

Statistical Analysis And Modeling Of Ovarian And Breast Cancer, Muditha V. Devamitta Perera

USF Tampa Graduate Theses and Dissertations

The objective of the present study is to investigate key aspects of ovarian and breast cancers, which are two main causes of mortality among women. Identification of the true behavior of survivorship and influential risk factors is essential in designing treatment protocols, increasing disease awareness and preventing possible causes of disease. There is a commonly held belief that African Americans have a higher risk of cancer mortality. We studied racial disparities of women diagnosed with ovarian cancer on overall and disease-free survival and found out that there is no significant difference in the survival experience among the three races: Whites, …

Short Communication: Multi-Scale Topographic Anisotropy Patterns On A Barrier Island, Chris Houser, Michael Bishop, Phil Wernette

Earth & Environmental Sciences Publications

Barrier islands exhibit a range of landforms that reflect the complex and varied combination of coastal and aeolian processes realized over the evolution of the island. A detailed analysis of the topography can be used to describe the evolution of a barrier island and provide insight on how it may be affected by a change in sea level, storm activity and wind exposure patterns. Topographic anisotropy, or the directional dependence of relief of landforms, can be used to determine the relative importance of different processes to island evolution at a range of scales. This short communication describes the use of …

The Firece Green Fire: Vol. 8 Issue 3, Wofford College Environmental Studies Program

The Fierce Green Fire

No abstract provided.

The Detection Of An Invasive Pathogen Through Chemical And Biological Means For The Protection Of Commercial Crops, Alison G. Simon

FIU Electronic Theses and Dissertations

Standoff detection of targets using volatiles is essential when considering substances that are hazardous or dangerous, or for which the presence or location is unknown. For many invasive biological threats, their presence is often not realized until they have begun visibly affecting and spreading through crops or forests. The fungus Raffaelea lauricola is a biothreat vectored by the invasive beetle Xyleborus glabratus, or redbay ambrosia beetle (RAB), whose presence in avocado groves is currently detectable by visual inspection. Once visually identified, the affected trees must be removed and destroyed to protect those remaining trees. However, if the fungus is …

On A Frobenius Problem For Polynomials, Ricardo Conceição, R. Gondim, M. Rodriguez

Math Faculty Publications

We extend the famous diophantine Frobenius problem to a ring of polynomials over a field~k. Similar to the classical problem we show that the n = 2 case of the Frobenius problem for polynomials is easy to solve. In addition, we translate a few results from the Frobenius problem over ℤ to k[t] and give an algorithm to solve the Frobenius problem for polynomials over a field k of sufficiently large size.

Modeling And Reasoning With Changing Intentions: An Experiment, Alicia M. Grubb, Marsha Chechik

Computer Science: Faculty Publications

Existing modeling approaches in requirements engineering assume that stakeholder goals are static: Once set, they remain the same throughout the lifecycle of the project. Of course, such goals, like anything else, may change over time. In earlier work, we introduced Evolving Intentions: An approach that allows stakeholders to specify how evaluations of goal model elements change over time. Simulation over Evolving Intentions enables stakeholders to ask a variety of 'what if' questions, and evaluate possible evolutions of a goal model. GrowingLeaf is a web-based tool that implements both the modeling and analysis components of this approach. In this paper, we …

Aligning Technology, Policy And Culture To Enhance Nuclear Security: A Comparative Analysis Of Nigeria And The U.S., Stephen Olumuyiwa Ariyo Dahunsi, John D. Auxier Ii, Joseph Ruric Stainback Iv, Howard Lewis Hall

International Journal of Nuclear Security

Around the world, current energy and climate change concerns have led to more nations adopting nuclear technology as an option for electricity generation. However, one of the challenges to the peaceful application of this technology is the possibility that it will be misused, or that terrorists with global reach may acquire nuclear materials. Nigeria is one country that has embraced the technology to solve its energy challenges, but the country is now faced with an upsurge in terrorism and uprisings staged by various ethnic groups. In addition, corruption is continually becoming a hindrance to national development. These challenges are critical …

Toxicant Formation In Dabbing: The Terpene Story, Jiries Meehan-Attrash, Wentai Luo, Robert M. Strongin

Chemistry Faculty Publications and Presentations

Inhalable, noncombustible cannabis products are playing a central role in the expansion of the medical and recreational use of cannabis. In particular, the practice of “dabbing” with butane hash oil has emerged with great popularity in states that have legalized cannabis. Despite their growing popularity, the degradation product profiles of these new products have not been extensively investigated. The study herein focuses on the chemistry of myrcene and other common terpenes found in cannabis extracts. Methacrolein, benzene, and several other products of concern to human health were formed under the conditions that simulated realworld dabbing. The terpene degradation products observed …

The First Earthquake Site Assessments In Alberta, Canada, Joseph J. Farrugia

Electronic Thesis and Dissertation Repository

A thorough characterization of the site conditions at Alberta seismic stations is a vital component in assessing seismic hazard in the province. This thesis provides the first earthquake site characterizations in Alberta, including shear-wave velocity (V_S) depth profiles, estimates of the average shear-wave velocity in the upper 30 m (V_S30) and peak frequency (f_peak), and their validation for prediction of earthquake site amplification. National Building Code of Canada site classes are limited to C and D based on V_S30 estimates, with D being the predominant site class. Three …

Turbidity Dynamics During High-Flow Storm Events In The Clackamas River, Oregon 2006-2012, Micelis Clyde Doyle

Dissertations and Theses

Turbidity is a useful parameter that can be utilized to help understand the water quality in a river and is an expression of the optical properties of a liquid that cause light rays to be scattered and absorbed rather than transmitted in straight lines. A total of 41 storm events occurring during water years 2006-2012 were analyzed for this study. A hysteresis index (HI) was used to assess the difference in turbidity on the rising and falling limbs of a storm-hydrograph. The upstream Carter Bridge site exhibited a clockwise (C) hysteresis in 38 of 41 storm events and counter-clockwise (CC) …

Depositional And Environmental Controls On Oxygen And Carbon Isotope Compositions Of Late Pleistocene To Mid-Holocene Shelly Fauna From The Huron Basin, Ontario, Canada, Jane Wilson

Electronic Thesis and Dissertation Repository

The δ¹⁸O and δ¹³C of aragonitic mollusc shells were analyzed from nine sites in the Huron Basin, Ontario, Canada. These sites represent three lake phases spanning the Late Pleistocene to the mid-Holocene (Algonquin, Transitional, and Nipissing) and three depositional environments (fluvial, estuarine, and lacustrine). Depositional environment controls mollusc δ¹⁸O more strongly than climate. The source of carbon and climate control the δ¹³C of the shelly fauna. Shells from fluvial sites are most depleted of ¹⁸O and exhibit the greatest antipathetic δ¹³C-δ¹⁸O covariation. This reflects the dynamic nature of this system. Lacustrine sites have …

Assessing The Distribution Of Environmental Stewardship Organizations And Their Relationship To The Demographics Of Los Angeles County, Krystle M. Golly

LMU/LLS Theses and Dissertations

An equal distribution of environmental stewardship organizations across the urban landscape provides an environment that facilitates community empowerment. The systemic issues found in Los Angeles County play an important role in the social development of the area. Through the utilization of modern technology and geographical mapping software, spatial distribution of environmental stewardship organizations provided an understanding of social conditions within Los Angeles County. Environmental stewardship organizations provide the capability for communities to be more engaged in helping to eliminate environmental injustice. The comparison of minority populations at the census tract-level emphasizes the importance of connecting environmental stewardship organizations with their …

Investigations Into The Role Of Conformational Dynamics In Protein Function: Insights From Hydrogen/Deuterium Exchange-Mass Spectrometry, Courtney S. Fast

Electronic Thesis and Dissertation Repository

Deciphering protein structure and dynamics is a key prerequisite for understanding biological function. The current work aims to apply HDX-MS to improve the understanding of protein structure and dynamics for systems that remain challenging for other techniques. Following a general overview of the field (Chapter 1), Chapter 2 investigates the relationship between enzyme dynamics and catalysis. By conducting comparative HDX-MS measurements on rM1-PK during substrate turnover and in the resting state, catalytically active rM1-PK undergoes significant rigidification of the active site. However, virtually the same rigidification was seen upon exposing rM1-PK to substrate or product in the …

Thirty Years Of Research On Crown-Of-Thorns Starfish (1986–2016): Scientific Advances And Emerging Opportunities, Morgan S. Pratchett, Clemon F. Caballes, Jennifer C. Wilmes, Samuel Matthews, Camille Mellin, Hugh P. A. Sweatman, Lauren E. Nadler, Jon Brodie, Cassandra A. Thompson, Jessica Hoey, Arthur R. Bos, Maria Byrne, Vanessa Messmer, Sofia A. V. Fortunato, Carla C. M. Chen, Alexandra C. E. Buck, Russell C. Babcock, Sven Uthicke

Marine & Environmental Sciences Faculty Articles

Research on the coral-eating crown-of-thorns starfish (CoTS) has waxed and waned over the last few decades, mostly in response to population outbreaks at specific locations. This review considers advances in our understanding of the biology and ecology of CoTS based on the resurgence of research interest, which culminated in this current special issue on the Biology, Ecology and Management of Crown-of-Thorns Starfish. More specifically, this review considers progress in addressing 41 specific research questions posed in a seminal review by P. Moran 30 years ago, as well as exploring new directions for CoTS research. Despite the plethora of research on …

Altering The Coordination Of Iron Porphyrins By Ionic Liquid Nanodomains In Mixed Solvent Systems, Abderrahman Atifi, Michael D. Ryan

Chemistry Faculty Research and Publications

The solvent environment around iron porphyrin complexes was examined using mixed molecular/RTIL (room temperature ionic liquid) solutions. The formation of nanodomains in these solutions provides different solvation environments for substrates that could have significant impact on their chemical reactivity. Iron porphyrins (Fe(P)), whose properties are sensitive to solvent and ligation changes, were used to probe the molecular/RTIL environment. The addition of RTILs to molecular solvents shifted the redox potentials to more positive values. When there was no ligation change upon reduction, the shift in the E° values were correlated to the Gutmann acceptor number, as was observed for other …