Physical Sciences and Mathematics Commons^™

Policy Sustainability Issues: Case Study Of Cassava Farmers In Ikorodu. Lagos, Nigeria, Medinat Oluwatoyin Adetunji

Walden Dissertations and Doctoral Studies

The inconsistency and lack of continuity of Nigeria's agricultural policies impact the cassava sector. Despite being the world's biggest producer, the country is yet to benefit from the advantage due to a lack of sustainable growth. The situation manifests in terms of low productivity, low production level, and poor income to the farmers. The purpose of this qualitative study was to investigate the experiences and perceptions of the cassava farmers on cassava policies and the effect on their income and livelihoods in the Ikorodu local government of Lagos State. This qualitative study adopted a case study research design using participatory …

Exceptional Point Generated Robust Asymmetric High-Order Harmonics, Hamidreza Ramezani, Amir Targholizadeh, Gui-Lei Zhu, Xin-You Lü, Cem Yuce

Physics & Astronomy Faculty Publications

Using exceptional point dynamics in time and space modulated lattices we propose a new mechanism for generation of asymmetric robust higher harmonics. Specifically we design a metallic-silicon system with a complex optical potential spatiotemporally modulated along the length of the waveguide for this robust higher harmonic generation. In our system the dynamical equations associated with modal field amplitudes are described by a Jordan form Hamiltonian. This ultimately will allow for a unidirectional higher frequency generation which always has a maximum value for a specific length of the waveguide irrespective of the geometrical imperfections in the design of the waveguide. Furthermore, …

Molybdenum Oxide/Antimony Nanobelts Embedded In Asymmetric Membranes For Use As High-Capacity Lithium/Sodium-Ion Battery Anodes, Logan Williams

College of Graduate Studies: Theses & Dissertations

Lithium-ion batteries (LIB) are a key aspect of our daily lives, from smartphones to electric vehicles. Commercially available LIB use graphite anodes due to their reliability and safety. Graphite anodes present one key disadvantage: a relatively low theoretical capacity of 372 mAh g-1. It is of great importance that new research focuses on high-capacity anode materials to further our sustainability and usage of LIB. While increasing the performance of LIB is of great interest, developing alternative energy storage devices is gaining attention in academia and industry R&D. Sodium has become a topic of interest in recent years due to sodium’s …

Characterization Of Functionalized Carbon Nanotubes And Polystyrene/Cnt Composites Prepared With Microwave-Induced Polymerization, Allen Hulette

College of Graduate Studies: Theses & Dissertations

The use of carbon nanotubes in polymer composites can increase the mechanical properties of the resulting product. Carbon nanotubes are known to have chemical interactions that make them attracted to one another and fall out of solution. To reduce this agglomeration and disperse the mechanical properties throughout the composite, functional groups are covalently added to the carbon nanotubes. Another known property of carbon nanotubes is their ability to absorb microwaves and convert it into other forms of energy. This research investigates the effects of carbon nanotube absorption of microwaves and initiation of styrene monomer polymerization. Grignard reactions are used to …

The Synthesis And Biocatalytic Reduction Of Beta-Keto Alkynes, Rhema M. Francis

College of Graduate Studies: Theses & Dissertations

The preparation of enantiopure homopropargyl alcohols (but-3-yn-ols) is of high importance to the scientific community. They are employed as valuable pharmaceutical intermediates and are opportune to generate antiviral nucleoside analogues. Chiral inducement of these molecules thus far has been poor (low ee) and has constituted a key challenge for asymmetric synthesis in the last few decades. Enzyme-catalyzed enantioselective reductions of ketones have become popular to produce thus-prepared synthons on an industrial scale. Among them, biocatalysts (dehydrogenases, reductases) emerge as a biodegradable option for chemical transformations, in comparison to chiral catalysts that employ highly toxic metals. This research investigates the catalytic …

Non-Inferiority Testing: Kernel Estimation And Overlap Measure, Larie C. Ward

College of Graduate Studies: Theses & Dissertations

In non-inferiority testing, the decision of whether a proposed treatment is non-inferior to a reference treatment depends on model assumptions and choices of acceptable tolerance limits. Here, we consider a method that employs kernels to estimate the probability density functions of both the experimental and reference populations from two independent samples. Based on these densities, we introduce a quantity called the overlap coefficient or overlap measure. A bootstrap technique is helpful in exploring the distribution and variance empirically. We derive the distribution of this measure and define a hypothesis test that can be applied to the non-inferiority setting under some …

Synthesis And Characterization Of Multimetallic Clusters Featuring Iron, Cobalt, And 2,6-Bis(Trialkylsilylamino)Pyridines, Lynn Nguyen

College of Graduate Studies: Theses & Dissertations

Extended metal atom chain (EMAC) complexes are multimetallic complexes of three or more metals, often containing M-M bonds, with the metal ions arranged linearly. These complexes have significant potential as molecular wires. They can elicit unique physical properties and reactivities, sometimes a result of direct magnetic exchange between metal centers, especially when incorporating first row transition metals. The synthesis of the first linear, triiron (II) complex with 2,6-bis[(trimethylsilyl)amino]pyridine (H₂L^Me) featuring Fe-Fe bonding from our group, Fe₃L^Me₃, motivated the expansion of linear multimetallic EMAC complexes with Fe and Co, incorporating M-M bonds. …

Cryptography Through The Lens Of Group Theory, Dawson M. Shores

College of Graduate Studies: Theses & Dissertations

Cryptography has been around for many years, and mathematics has been around even longer. When the two subjects were combined, however, both the improvements and attacks on cryptography were prevalent. This paper introduces and performs a comparative analysis of two versions of the ElGamal cryptosystem, both of which use the specific field of mathematics known as group theory.

Modelling Muscle Activation Using Emg Signal, Mercy U. Okonna

College of Graduate Studies: Theses & Dissertations

(EMG) is a method for measuring muscle activity by an electrical signal, and is useful in studying motor control, postural control, and in physical therapy. A current research topic is creating an algorithm that can use the EMG signal to reliably classify a muscle as active or inactive. This thesis presents a classification algorithm for leg muscles with a single activation spike while walking. Time is rescaled into steps, which are identified using data from cameras measuring joint angles while walking. The algorithm is based on moving averages and a convex combination of mean signal strength in active and inactive …

Electrically Driven Reprogrammable Phase-Change Metasurface Reaching 80% Efficiency, Sajjad Abdollahramezani, Omid Hemmatyar, Mohammad Taghinejad, Hossein Taghinejad, Alex Krasnok, Ali A. Eftekhar, Christian Teichrib, Sanchit Deshmukh, Mostafa A. El-Sayed, Eric Pop, Matthias Wuttig, Andrea Alù, Wenshan Cai, Ali Adibi

Advanced Science Research Center

Phase-change materials (PCMs) offer a compelling platform for active metaoptics, owing to their large index contrast and fast yet stable phase transition attributes. Despite recent advances in phase-change metasurfaces, a fully integrable solution that combines pronounced tuning measures, i.e., efficiency, dynamic range, speed, and power consumption, is still elusive. Here, we demonstrate an in situ electrically driven tunable metasurface by harnessing the full potential of a PCM alloy, Ge₂Sb₂Te₅ (GST), to realize non-volatile, reversible, multilevel, fast, and remarkable optical modulation in the near-infrared spectral range. Such a reprogrammable platform presents a record eleven-fold change in …

Fish And Invertebrate Use Of Restored Vs. Natural Oyster Reefs In A Shallow Temperate Latitude Estuary, Jonathan H. Grabowski, Christopher J. Baillie, Adam Baukus, Rachael Carlyle, F. Joel Fodrie, Rachel K. Gittman, A. Randall Hughes, David L. Kimbro, Juhyung Lee, Hunter S. Lenihan, Sean P. Powers, Kevin Sullivan

University Faculty and Staff Publications

Coastal marine habitats continue to be degraded, thereby compelling largescale restoration in many parts of the world. Whether restored habitats function similarly to natural habitats and fully recover lost ecosystem services is unclear. In estuaries, oyster reefs have been degraded by multiple anthropogenic activities including destructive fishing practices and reduced water quality, motivating restoration to maintain oyster fisheries and other ecosystem services, often at relatively high cost. We compared fish and invertebrate communities on recently restored (0–1 year post-restoration), older restored (3–4 years post-restoration), and natural oyster reefs to determine if and when restored reefs support functionally similar faunal communities. …

Investigaion Of The Gamma Hurdle Model For A Single Population Mean, Alissa Jacobs

Electronic Theses and Dissertations

A common issue in some statistical inference problems is dealing with a high frequency of zeroes in a sample of data. For many distributions such as the gamma, optimal inference procedures do not allow for zeroes to be present. In practice, however, it is natural to observe real data sets where nonnegative distributions would make sense to model but naturally zeroes will occur. One example of this is in the analysis of cost in insurance claim studies. One common approach to deal with the presence of zeroes is using a hurdle model. Most literary work on hurdle models will focus …

On-Road Vehicle Emission Measurements And Their Use In Evaluating Emission Control Effectiveness {Presentation}, Gary A. Bishop

Fuel Efficiency Automobile Test Publications

No abstract provided.

Monitoring And Modelling The Dynamics Of The Cellular Glycolysis Pathway: A Review And Future Perspectives, Nitin Patil, Hugh Byrne, Orla L. Howe, Paul A. Cahill

Articles

Background

The dynamics of the cellular glycolysis pathway underpin cellular function and dysfunction, and therefore ultimately health, disease, diagnostic and therapeutic strategies. Evolving our understanding of this fundamental process and its dynamics remains critical.

Scope of review

This paper reviews the medical relevance of glycolytic pathway in depth and explores the current state of the art for monitoring and modelling the dynamics of the process. The future perspectives of label free, vibrational microspectroscopic techniques to overcome the limitations of the current approaches are considered.

Major conclusions

Vibrational microspectroscopic techniques can potentially operate in the niche area of limitations of other …

The Lick Agn Monitoring Project 2016: Velocity-Resolved Hβ Lags In Luminous Seyfert Galaxies, Vivian U, Aaron J. Barth, H. Alexander Vogler, Hengxiao Guo, Tommaso Treu, Vardha N. Bennert, Gabriela Canalizo, Alexei V. Filippenko, Elinor Gates, Frederick Hamann, Michael D. Joner, Matthew A. Malkan, Anna Pancoast, Peter R. Williams, Jong-Hak Woo, Bela Abolfathi, L. E. Abramson, Stephen F. Armen, Hyun-Jin Bae, Thomas Bohn, Benjamin D. Boizelle, Azalee Bostroem, Andrew Brandel, Thomas G. Brink, Sanyum Channa, M. C. Cooper, Maren Cosens, Edward Donohue, Sean P. Fillingham, Diego González-Buitrago, Goni Halevi, Andrew Halle, Carol E. Hood, Keith Horne, J. Chuck Horst, Maxime De Kouchkovsky, Benjamin Kuhn, Sahana Kumar, Douglas C. Leonard, Donald Loveland, Christina Manzano-King, Ian Mchardy, Raúl Michel, Melanie Kae B. Olaes, Daeseong Park, Songyoun Park, Liuyi Pei, Timothy W. Ross, Jordan N. Runco, Jenna Samuel, Javier Sánchez, Bryan Scott, Remington O. Sexton, Jaejin Shin, Isaac Shivvers, Chance L. Spencer, Benjamin E. Stahl, Samantha Stegman, Isak Stomberg, Stefano Valenti, L. Villafaña, Jonelle L. Walsh, Heechan Yuk, Weikang Zheng

Physics

We carried out spectroscopic monitoring of 21 low-redshift Seyfert 1 galaxies using the Kast double spectrograph on the 3 m Shane telescope at Lick Observatory from 2016 April to 2017 May. Targeting active galactic nuclei (AGNs) with luminosities of λLλ(5100 Å) ≈ 1044 erg s−1 and predicted Hβ lags of ∼20–30 days or black hole masses of 107–108.5 M⊙, our campaign probes luminosity-dependent trends in broad-line region (BLR) structure and dynamics as well as to improve calibrations for single-epoch estimates of quasar black hole masses. Here we present the first results from the campaign, including …

Bias Mitigation For Toxicity Detection Via Sequential Decisions, Lu Cheng, Ahmadreza Mosallanezhad, Yasin N. Silva, Deborah Hall, Huan Liu

Computer Science: Faculty Publications and Other Works

Increased social media use has contributed to the greater prevalence of abusive, rude, and offensive textual comments. Machine learning models have been developed to detect toxic comments online, yet these models tend to show biases against users with marginalized or minority identities (e.g., females and African Americans). Established research in debiasing toxicity classifiers often (1) takes a static or batch approach, assuming that all information is available and then making a one-time decision; and (2) uses a generic strategy to mitigate different biases (e.g., gender and racial biases) that assumes the biases are independent of one another. However, in real …

Biocatalytic Intramolecular C−H Aminations Via Engineered Heme Proteins: Full Reaction Pathways And Axial Ligand Effects, Yang Wei, Melissa Conklin, Yong Zhang

Chemistry: Faculty Publications and Other Works

Engineered heme protein biocatalysts provide an efficient and sustainable approach to develop amine-containing compounds through C−H amination. A quantum chemical study to reveal the complete heme catalyzed intramolecular C−H amination pathway and protein axial ligand effect was reported, using reactions of an experimentally used arylsulfonylazide with hemes containing L=none, SH−, MeO−, and MeOH to simulate no axial ligand, negatively charged Cys and Ser ligands, and a neutral ligand for comparison. Nitrene formation was found as the overall rate-determining step (RDS) and the catalyst with Ser ligand has the best reactivity, consistent with experimental reports. Both RDS and non-RDS (nitrene transfer) …

Healing Earth In A Time Of Crisis: Curriculum For Integral Ecology, Caleb Steindam

Dissertations

This intrinsic multiple case study examined secondary- and university-level educators’ experiences teaching with Healing Earth, a curriculum developed by the International Jesuit Ecology Project at Loyola University Chicago, which merges scientific, social, spiritual, and ethical analyses of pressing ecological issues. Based on the conceptual framework of integral ecology, Healing Earth is a response to Pope Francis’s (2015a) call for “a new way of thinking about human beings, life, society and our relationship with nature” (§215).

This study primarily consisted of in-depth interviews with educators who have used Healing Earth in a variety of secondary and post-secondary Catholic educational contexts. A …

Chicago Community Area Data, 1930-2010, Nate Falling, Jacob Nelson, Miguel Torres, Richard T. Melstrom

School of Environmental Sustainability: Faculty Publications and Other Works

We are releasing a set of community area
statistics collected from fact book and census
profile data series. These statistics are in the file
Chicago_Community_Area_Data_1930-2010,
which is available from the attached dataset. The statistics do not reflect all of the
data contained in the historical sources.
Additional digitized data can be found at
https://robparal.com/chicago-data/.

Detection Of Overlapping Passive Manipulation Techniques In Image Forensics, Gianna S. Lint, Umit Karabiyik

Annual ADFSL Conference on Digital Forensics, Security and Law

With a growing number of images uploaded daily to social media sites, it is essential to understand if an image can be used to trace its origin. Forensic investigations are focusing on analyzing images that are uploaded to social media sites resulting in an emphasis on building and validating tools. There has been a strong focus on understanding active manipulation or tampering techniques and building tools for analysis. However, research on manipulation is often studied in a vacuum, involving only one technique at a time. Additionally, less focus has been placed on passive manipulation, which can occur by simply uploading …

Interaction With Augmented Reality Sandbox Does Not Produce Greater Gains In Topographic Map Skills For Undergraduate Students, Celeste Kenworthy

Honors Program: Senior Projects (Public)

The augmented reality (AR) sandbox allows students to interact with topographic maps in a 3D space. Being able to understand topographic maps is important to geologists and they are taught in many introductory geology courses. Recent research has focused on whether the AR sandbox can improve students’ topographic map skills. Previous studies have found that students who interact with the AR sandbox do not score significantly better on topographic map assessments (TMAs) than their peers. One proposed reason for this is the limited time students have to interact with the AR sandbox. This study sought to address this by creating …

Climate Adaptation For Tropical Island Land Stewardship: Adapting A Workshop Planning Process To Hawai'i, Ryan J. Longman, Courtney L. Peterson, Madeline Baroli, Abby G. Frazier, Zachary Cook, Elliott W. Parsons, Maude Dinan, Katie L. Kamelamela, Caitriana Steele, Reanna Burnett, Chris Swanston, Christian P. Giardina

Geography

No abstract provided.

The Resilience Adaptation Feasibility Tool (Raft) As An Approach For Incorporating Equity Into Coastal Resilience Planning And Project Implementation, Juita-Elena (Wie) Yusuf, Tanya Denckla Cobb, Elizabeth Andrews, Sierra Gladfelter, Gray Montrose

School of Public Service Faculty Publications

As coastal communities across the U.S. and worldwide undertake efforts to enhance their resilience to coastal hazards, they must do so while ensuring that all voices are heard, addressing and preventing disparate impacts, and, ultimately, increasing resilience in an equitable way. The Resilience Adaptation Feasibility Tool (RAFT) assists coastal communities in incorporating equity into resilience planning and implementation of projects to increase resilience. The RAFT includes social and economic dimensions in assessment of resilience and focuses on how localities can build resilience equitably. The RAFT process has three phases -- a scorecard assessment, development of a resilience action checklist that …

Evaluating Science Communication Efforts And Citizen Scientists' Knowledge Of, Attitude Toward, And Behavioral Intentions Related To The North American River Otter, Karlee D. Jewell

Cal Poly Humboldt theses and projects

Citizen Science (CS) and scientific visual, spatial, and graphic art projects have the potential to engage community members, provide opportunities for advances in scientific literacy, increase interest in science and local environmental knowledge, and elevate pro-environmental attitudes. CS depends upon public participation, and motivation for participation is varied, including participants’ desire to learn something new or contribute to science or scientific knowledge. An effective CS project will be rooted in an understanding of individuals’ motivations for participation, striving to meet those motivations, and effectively evaluating not only the scientific outputs of the project but also whether participants’ motivations are being …

Carnivore And Ungulate Responses To Cattle In A Grazed Forest Ecosystem, Rebecca Carniello

Cal Poly Humboldt theses and projects

Habitat disturbance, a leading threat to biological diversity, comes in many forms and can alter the behavior of wildlife and reduce the amount of suitable habitat. Livestock grazing, a form of habitat disturbance, is the most widespread influence on native ecosystems of western North America. Research on the impacts of introduced domestic herbivores on wild carnivores and ungulates varies, and the degree to which wildlife species are affected is often species-specific. I used remote trail cameras to compare the activity patterns of black bears (Ursus americanus), coyotes (Canis latrans), bobcats (Lynx rufus), mountain lions …

A Pantropical Assessment Of Deforestation Caused By Industrial Mining, Stefan Giljum, Victor Maus, Nikolas Kuschnig, Sebastian Luckeneder, Michael Tost, Laura J. Sonter, Anthony J. Bebbington

Geography

Growing demand for minerals continues to drive deforestation worldwide. Tropical forests are particularly vulnerable to the environmental impacts of mining and mineral processing. Many local- to regional-scale studies document extensive, long-lasting impacts of mining on biodiversity and ecosystem services. However, the full scope of deforestation induced by industrial mining across the tropics is yet unknown. Here, we present a biome-wide assessment to show where industrial mine expansion has caused the most deforestation from 2000 to 2019. We find that 3,264 km2 of forest was directly lost due to industrial mining, with 80% occurring in only four countries: Indonesia, Brazil, Ghana, …

Sidebar: Observations Of Declining Primary Productivity In The Western Bering Strait, Karen E. Frey, Jaclyn Clement Kinney, Larry V. Stock, Robert Osinski

Geography

No abstract provided.

Dbsnap 2: New Features To Construct Database Queries By Snapping Blocks, Yasin N. Silva, Alexis Loza, Humberto Razente

Computer Science: Faculty Publications and Other Works

Block-based environments for creating computer programs have become very useful learning tools in computer science as they enable focusing on the logic of a program rather than on its syntactical details. While most block-based environments support conventional (imperative) instructions, a few tools have been proposed to create database queries. One of these tools is DBSnap, a highly dynamic and open-source tool to create database query trees by dragging and connecting visual blocks representing datasets and database operators. In this paper, we introduce DBSnap 2, an extension of DBSnap that provides a set of improvements to facilitate the creation of simple …

Towards An Active Foveated Approach To Computer Vision, Dario Dematties, Silvio Rizzi, George K. Thiruvathukal, Alejandro Javier Wainselboim

Computer Science: Faculty Publications and Other Works

In this paper, a series of experimental methods are presented explaining a new approach towards active foveated Computer Vision (CV). This is a collaborative effort between researchers at CONICET Mendoza Technological Scientific Center from Argentina, Argonne National Laboratory (ANL), and Loyola University Chicago from the US. The aim is to advance new CV approaches more in line with those found in biological agents in order to bring novel solutions to the main problems faced by current CV applications. Basically this work enhance Self-supervised (SS) learning, incorporating foveated vision plus saccadic behavior in order to improve training and computational efficiency without …

Temporally Sliced Photon Primitives For Volumetric Time-Of-Flight Rendering, Yang Liu

Dartmouth College Master’s Theses

Traditional steady-state rendering assumes that the light transport has already reached equilibrium. In contrast, time-of-flight rendering removes this assumption and recovers the pattern of light at extremely high temporal resolutions. This novel rendering modality not only provides a way to visualize the propagation of light, but can also empower the advances in time-of-flight imaging and its corresponding applications.

Building on previous work in steady-state volumetric rendering, this thesis introduces a novel framework for deriving new Monte Carlo estimators for solving the time-of-flight rendering problem in participating media. Conceptually, our method starts with any steady-state photon primitive, like a photon plane …