Physical Sciences and Mathematics Commons^™

Social Learning Of Avoidance Behaviors: Trap Aversion In Captive Coyotes, Julie Young, Jeffrey T. Schultz, Buck Jolley, Nekol Basili, John P. Draper

United States Department of Agriculture Wildlife Services: Staff Publications

Social learning can help animals gain knowledge rapidly and may enhance survival. In species that are subjected to capture in foothold traps and then lethally removed, such as the coyote (Canis latrans), learning to avoid traps is critical to survival. Here, we tested social learning of trap avoidance behavior in three experimental scenarios with captive coyotes. In the first experiment, coyotes observed an unfamiliar coyote get captured in a foothold trap (i.e., demonstrator) or did not observe a demonstrator and were therefore naïve to traps. The coyotes that observed a demonstrator showed similar latencies to approach the trap …

Predicting Consistent Foraging Ecologies Of Migrating Waterbirds: Using Stable Isotope And Parasite Measurements As Indicators Of Landscape Use, Kate L. Sheehan, Brian S. Dorr, Stephen A. Clements, Terrel W. Christie, Katie Hanson-Dorr, Scott A. Rush, J. Brian Davis

United States Department of Agriculture Wildlife Services: Staff Publications

The emergence of novel human pathogens is frequently linked with zoonotic events and human-wildlife interactions that promote disease transmission. Consequently, surveillance of wildlife populations for candidate diseases that could spread to humans is beneficial, but requires widespread collections of numerous samples. A legitimate means to acquire large sample sizes of waterfowl is through cooperation between researchers and hunters, who also work in concert with natural resource managers, landowners, and agricultural entities -e.g., aquaculture facilities. In addition to understanding the occurrence and spread of parasites and pathogens by birds, these samples can be used to answer questions about the ecology of …

Adaptive Risk-Based Targeted Surveillance For Foreign Animal Diseases At The Wildlife-Livestock Interface, Ryan S. Miller, Sarah N. Bevins, Gericke Cook, Ross Free, Kim M. Pepin, Thomas Gidlewski, Vienna Brown

United States Department of Agriculture Wildlife Services: Staff Publications

Animal disease surveillance is an important component of the national veterinary infrastructure to protect animal agriculture and facilitates identification of foreign animal disease (FAD) introduction. Once introduced, pathogens shared among domestic and wild animals are especially challenging to manage due to the complex ecology of spillover and spillback. Thus, early identification of FAD in wildlife is critical to minimize outbreak severity and potential impacts on animal agriculture as well as potential impacts on wildlife and biodiversity. As a result, national surveillance and monitoring programs that include wildlife are becoming increasingly common. Designing surveillance systems in wildlife or, more importantly, at …

No Panacea Attractant For Wild Pigs (Sus Scrofa), But Season And Location Matter, Nathan P. Snow, Caitlin A. Kupferman, Michael J. Lavelle, Kim M. Pepin, Madeline H. Melton, Whitney J. Gann, Kurt C. Vercauteren, James C. Beasley

United States Department of Agriculture Wildlife Services: Staff Publications

Wild pigs (Sus scrofa) are a prolific invasive species throughout many regions of the world that cause extensive economic and environmental damage. Trapping is a common strategy for reducing their populations with baits (i.e., food) and attractants (e.g., scents) used to lure wild pigs into traps. However, there is little information on which scent attractants may attract wild pigs more readily and rapidly across regions and seasons. We examined 60 scent attractants for wild pigs that could be used to increase trapping success across three seasons (winter, spring, and fall) and in two geographic regions, including a warm …

Integrating Data Types To Estimate Spatial Patterns Of Avian Migration Across The Western Hemisphere, Timothy D. Meehan, Sarah P. Saunders, William V. Deluca, Nicole L. Michel, Joanna Grand, Jill L. Deppe, Miguel F. Jimenez, Erika J. Knight, Nathaniel E. Seavy, Melanie A. Smith, Lotem Taylor, Chad Witko, Michael E. Akresh, David R. Barber, Erin M. Bayne, James C. Beasley, Jerrold L. Belant, Richard O. Bierregaard, Keith L. Bildstein, Than J. Boves, John N. Brzorad, Steven P. Campbell, Antonio Celis-Murillo, Hilary A. Cooke, Robert Domenech, Laurie Goodrich, Elizabeth A. Gow, Aaron Haines, Michael T. Hallworth, Jason M. Hill, Amanda E. Holland, Scott Jennings, Roland Kays, Tommy King, Stuart A. Mackenzie, Peter P. Marra, Rebecca A. Mccabe, Kent P. Mcfarland, Michael J. Mcgrady, Ron Melcer, D. Ryan Norris, Russell E. Norvell, Olin E. Rhodes, Christopher C. Rimmer, Amy L. Scarpignato, Adam Shreading, Jesse L. Watson, Chad R. Wilsey

United States Department of Agriculture Wildlife Services: Staff Publications

For many avian species, spatial migration patterns remain largely undescribed, especially across hemispheric extents. Recent advancements in tracking technologies and high-resolution species distribution models (i.e., eBird Status and Trends products) provide new insights into migratory bird movements and offer a promising opportunity for integrating independent data sources to describe avian migration. Here, we present a three-stage modeling framework for estimating spatial patterns of avian migration. First, we integrate tracking and band re-encounter data to quantify migratory connectivity, defined as the relative proportions of individuals migrating between breeding and nonbreeding regions. Next, we use estimated connectivity proportions along with eBird occurrence …

Summer Habitat Use And Movements Of Invasive Wild Pigs (Sus Scrofa) In Canadian Agro-Ecosystems, Corey J. Kramer, Melanie R. Boudreau, Ryan S. Miller, Ryan Powers, Kurt C. Vercauteren, Ryan K. Brook

United States Department of Agriculture Wildlife Services: Staff Publications

Resource selection informs understanding of a species’ ecology and is especially pertinent for invasive species. Since introduced to Canada, wild pigs (Sus scrofa Linnaeus, 1978) remain understudied despite recognized negative impacts on native and agricultural systems globally. Elsewhere in North America, pigs typically use forests and forage in agricultural crops. We hypothesized Canadian wild pigs would behave similarly, and using GPS locations from 15 individuals, we examined diel and seasonal resource selection and movement in the Canadian prairie region. Forests were predominately selected during the day, while corn (Zea mays L.), oilseeds, and wheat (Triticum aestivum L.) …

Ontario’S Double-Crested Cormorant Hunting Season May Be Ineffective But That Doesn’T Mean There Are No Conflict Issues, Brian S. Dorr, David G. Fielder, James R. Jackson, James F. Farquhar, Douglas W. Schultz, Randall M. Claramunt

United States Department of Agriculture Wildlife Services: Staff Publications

No abstract provided.

Influence Of Landscape Attributes On Virginia Opossum Density, David A. Bernasconi, Wesley C. Dixon, Matthew T. Hamilton, James L. Helton, Richard B. Chipman, Amy T. Gilbert, James C. Beasley, Olin E. Rhodes Jr., Guha Dharmarajan

United States Department of Agriculture Wildlife Services: Staff Publications

TheVirginia opossum (Didelphis virginiana), North America's only marsupial, has a range extending from southern Ontario, Canada, to the Yucatan Peninsula, Mexico, and from the Atlantic seaboard to the Pacific. Despite the Virginia opossum's taxonomic uniqueness in relation to other mammals in North America and rapidly expanding distribution, its ecology remains relatively understudied. Our poor understanding of the ecology of this important mesopredator is especially pronounced in the rural southeastern United States. Our goal was to estimate effects of habitat on opossum density within an extensive multiyear spatial capture‐recapture study. Additionally, we compared the results of this spatial capture‐recapture …

Managing Roof Rats In Citrus Orchards: Initial Efforts Toward Building An Integrated Pest Management Program, Roger A. Baldwin, Justine A. Smith, Ryan Meinerz, Aaron B. Shiels

United States Department of Agriculture Wildlife Services: Staff Publications

Roof rats cause extensive damage in orchards throughout the world. Integrated Pest Management (IPM) systems are the best option for managing rodents, yet few management systems have been developed and tested to control roof rats in agricultural settings. We initiated a study in 2020 to provide the foundation for an IPM program to manage roof rats in California citrus orchards. Our initial efforts centered on developing effective monitoring strategies for roof rats to determine when management actions are needed, assessing rat movement patterns to determine proper placement of management tools, and conducting initial tests of Goodnature A24 self-resetting traps and …

Development Of A Novel Vertebrate Pesticide For The Invasive Small Indian Mongoose, Carmen Antaky, Steven C. Hess, Israel Leinbach, Robert T. T. Sugihara, Emily W. Ruell, Shane Siers

United States Department of Agriculture Wildlife Services: Staff Publications

Small Indian mongooses are detrimental introduced predators in the United States, where they depredate native species, serve as vector of disease, and threaten public safety. Due to the risk of accidental introduction to mongoose-free islands, high cost and limitations to trapping, and no national (Section 3) Environmental Protection Agency (EPA)-registered toxicants for mongoose control, there is a need for an efficacious toxic bait for mongooses for use in conservation areas and at points of entry in the United States. Over the last five years, the National Wildlife Research Center (NWRC) worked to develop a toxic bait for mongooses for registration …

Evidence For Irruptive Fluctuation In Axis Deer Of Hawai‘I, Steven C. Hess, Jonathan Sprague, Jacob Muise

United States Department of Agriculture Wildlife Services: Staff Publications

Axis deer on the Hawaiian Islands of Maui, Lāna‘i, and Moloka‘i simultaneously experienced one of the most dramatic population crashes on record in 2020-2021, which coincided with extended drought conditions and prompted an emergency declaration for these islands. This phenomenon has been anecdotally documented during previous drought events in 2011-2012, but never formally studied. Newspaper articles document abundant deer becoming a nuisance to agriculture and natural resources, and then experiencing high mortality during droughts. This phenomenon fits Caughley’s (1970) operational definition of eruptive (sic) fluctuation “…as an increase in numbers over at least two generations, followed by a marked decline.” …

Abert’S Squirrel Management In Support Of Endangered Mount Graham Red Squirrel Recovery In Arizona, Aaron R. Morehead, Christopher Carillo, Holly Hicks, Wade Sanders, David L. Bergman

United States Department of Agriculture Wildlife Services: Staff Publications

Recovery of the endangered Mount Graham red squirrel (MGRS) will likely be long and challenging. Its limited habitat, isolation to Pinaleño Mountain range, and demographic characteristics restrict its ability to rebound quickly from threats that impact both the squirrel and its habitat. Currently, threats to the MGRS include habitat degradation and loss through high-severity wildfire, fire suppression activities, insect outbreaks, climate change, and human development, and predation, as well as competition with Abert’s squirrels. The most recent wildfire in 2017 impacted over 48,000 acres of already reduced habitat. A critical first step is to protect and manage the remaining population …

Predation Thresholds For Reintroduction Of Native Avifauna Following Suppression Of Invasive Brown Treesnakes On Guam, Robert M. Mcelderry, Eben H. Paxton, Andre V. Nguyen, Shane R. Siers

United States Department of Agriculture Wildlife Services: Staff Publications

The brown treesnake (BTS) (Boiga irregularis) invasion on Guåhan (in English, Guam) led to the extirpation of nearly all native forest birds. In recent years, methods have been developed to reduce BTS abundance on a landscape scale. To help assess the prospects for the successful reintroduction of native birds to Guåhan following BTS suppression, we modeled bird population persistence based on their life history characteristics and relative sensitivity to BTS predation. We constructed individual-based models and simulated BTS predation in hypothetical founding populations for each of seven candidate bird species. We represented BTS predation risk in two steps: …

Migratory Movements And Home Ranges Of Geographically Distinct Wintering Populations Of A Soaring Bird, Ryo Ogawa, J. Brian Davis, D. Tommy King, L. Wes Burger, Bronson K. Strickland, Marsha A. Sovada, Guiming Wang, Fred L. Cunningham

United States Department of Agriculture Wildlife Services: Staff Publications

Migratory soaring birds exhibit spatiotemporal variation in their circannual movements. Nevertheless, it remains uncertain how different winter environments affect the circannual movement patterns of migratory soaring birds. Here, we investigated annual movement strategies of American white pelicans Pelecanus erythrorhynchos (hereafter, pelican) from two geographically distinct wintering grounds in the Southern and Northern Gulf of Mexico (GOM).We hypothesized that hourly movement distance and home range size of a soaring bird would differ between different geographic regions because of different thermals and wind conditions and resource availability. We calculated average and maximum hourly movement distances and seasonal home ranges of GPS-tracking pelicans. …

Global In Time Self-Interacting Dirac Fields In The De Sitter Space, Karen Yagdjian

School of Mathematical & Statistical Sciences Faculty Publications

In this paper the semilinear equation of the spin-12 fields in the de Sitter space is investigated. We prove the existence of the global in time small data solution in the expanding de Sitter universe. Then, under the Lochak–Majorana condition, we prove the existence of the global in time solution with large data. The sufficient conditions for the solutions to blow up in finite time are given for large data in the expanding and contracting de Sitter spacetimes. The influence of the Hubble constant on the lifespan is estimated.

Online List Coloring For Signed Graphs, Melissa Tupper, Jacob A. White

School of Mathematical & Statistical Sciences Faculty Publications

We generalize the notion of online list coloring to signed graphs. We define the online list chromatic number of a signed graph, and prove a generalization of Brooks’ Theorem. We also give necessary and sufficient conditions for a signed graph to be degree paintable, or degree choosable. Finally, we classify the 2-list-colorable and 2-list-paintable signed graphs.

Game Between The Third Party Payment Service Provider And Bank In Mobile Payment Market, Hui Jiang, Junhai Ma, Zhaosheng Feng

School of Mathematical & Statistical Sciences Faculty Publications

With the innovation and integration of the Internet and the financial industry, the third-party payment market has developed greatly and has great potential. This paper discusses the duopoly game between third-party payment service providers and banks, which are the main participants in the mobile payment market. By constructing Nash game model, the conditions of equilibrium point, stability and bifurcation are analyzed. The effects of adjusting parameters and cooperation coefficient on business volume and profit are discussed. The conclusions are as follows: excessive investment will lead to unpredictable fluctuations in the market and fall into chaos; By strengthening cooperation, all participants …

Susceptibility Of Wild Canids To Sars-Cov-2, Stephanie M. Porter, Aim E. Hartwig, Helle Bielefeldt-Ohmann, Angela M. Bosco-Lauth, J. Jeffrey Root

United States Department of Agriculture Wildlife Services: Staff Publications

We assessed 2 wild canid species, red foxes (Vulpes vulpes) and coyotes (Canis latrans), for susceptibility to SARS-CoV-2. After experimental inoculation, red foxes became infected and shed infectious virus. Conversely, experimentally challenged coyotes did not become infected; therefore, coyotes are unlikely to be competent hosts for SARS-CoV-2.

Throughout the COVID-19 pandemic, multiple instances of natural infections with SARS-CoV-2 have been reported in pet dogs, likely after exposure to an infected human (1–3). Domestic dogs appear to be minimally susceptible to SARS-CoV-2, as indicated by experimental inoculations resulting in reverse transcription PCR–positive samples and low titer antibody responses but no clinical …

Exploring The Value Of A Global Gene Drive Project Registry, Riley I. Taitingfong, Antoinette J. Piaggio, Cinnamon S. Bloss, Et Al.

United States Department of Agriculture Wildlife Services: Staff Publications

Recent calls to establish a global project registry before releasing any gene-drive-modified organisms (GDOs) have suggested a registry could be valuable to coordinate research, collect data to monitor and evaluate potential ecological impacts, and facilitate transparent communication with community stakeholders and the general public. Here, we report the results of a multidisciplinary expert workshop on GDO registries convened on 8–9 December 2020 involving 70 participants from 14 countries. Participants had expertise in gene drive design, conservation and population modeling, social science, stakeholder engagement, governance and regulation, international policy, and vector control; they represented 45 organizations, spanning national and local governmental …

Lake Huron Shoreline Analysis, Shubham Satish Nandanwar

Theses and Dissertations (Comprehensive)

Lake Huron is a popular tourist destination and is home to several businesses and residents. Since the shoreline is dynamic and is subject to change over the years due to several factors such as a change in water level, soil type, human encroachment, etc., these locations tend to encounter floods due to increased water levels and wind speed. This causes erosion and loss to the properties along the shoreline.

This study is based on two areas of interest named Pinery Provincial Park and Sauble Beach which are located on the shoreline of Lake Huron where Pinery Provincial Park is a …

Alpine Shrub Tundra Water Storage And Runoff Dynamics In The Mackenzie Mountains, Sahtú Territory, Nt, Geoffrey Kershaw

Theses and Dissertations (Comprehensive)

Alpine regions receive large volumes of precipitation and are important to local and regional water balances, particularly during baseflow periods of winter cold and summer drought when the larger basin area is frozen and/or water limited. Alpine headwaters in western Canada are expected to warm and receive more precipitation during the coming decades, with implications for groundwater recharge and streamflow generation within these systems and the regional river networks to which they contribute. Throughout the North, thawing peat plateaus and other ice-rich permafrost features are resulting in an increased extent of thermokarst and wetland land cover. This transition places infrastructure …

Coastal Landform Change Influences On Endangered Five-Lined Skink Distribution At Northwest Beach, Point Pelee National Park, Canada, Evan Fortushniok

Theses and Dissertations (Comprehensive)

As park visitation increased to Point Pelee National Park up until its peak in 1963, the installation of infrastructure for the purpose of supporting the recreational interest grew with it. At Northwest Beach, large parking lots were built into the coastal landscape and by the 1970s large areas of sand dunes continued to be heavily impacted by the installation of visitor associated infrastructure. The infrastructure resulted in the stabilization of sand on the beach side of the parking lot, resulting in an artificially stabilized and heavily vegetated dune. Over the last few decades, the park slowly reduced the size and …

Air Quality: Assessment Of Pollutant Levels And Chemistry In Kitchener, On Using Multisensor Pods, Wisam Mohammed

Theses and Dissertations (Comprehensive)

Air quality is a growing concern amongst governmental bodies worldwide. A large number of scientific studies accumulated over the past 25 years suggest that poor ambient air quality is attributed to adverse health effects, especially in vulnerable communities that exhibit pre-existing conditions. The United Nations Children’s Fund (UNICEF) reported around 600 000 deaths globally in children under the age of 5 as a result of acute lower respiratory infections caused by poor air quality. With the current statistics on air quality impacts, it is clear that more needs to be done. This MSc work aims to put into perspective the …

Development Of A New Spe Uplc–Ms/Ms Method For Extraction And Quantitation Of Toluene Diamine On Gloves Following Toluene Diisocyanate Exposure, Asma Daoud, Pierre-Luc Cloutier, Sébastien Gagné, Livain Breau, Jacques Lesage

Études primaires

Rationale

Toluene diisocyanate (TDI) is a highly reactive isocyanate commonly used as a mixture of 2,4- and 2,6- isomers in the production of flexible foams. Exposure to TDI occurs primarily through vapour inhalation in workplaces where TDI is produced or used, but dermal exposure is also possible during some tasks. To ensure workplace safety, accurate monitoring of TDI and toluene diamine (TDA) levels is required. Methods of quantifying field effectiveness of gloves in preventing dermal exposure have not been established. Therefore, there is a need to develop a new practical method for assessing glove effectiveness for TDI/TDA.

Method

A new …

Morphologic Clustering Of Earcanals Using Deep Learning Algorithm To Design Artificial Ears Dedicated To Earplugs Attenuation Measurement, Bastien Poissenot-Arrigoni, Chun Hong Law, Djamal Berbiche, Franck Sgard, Olivier Doutres

Études primaires

Designing earplugs adapted for the widest number of earcanals requires acoustical test fixtures (ATFs) geometrically representative of the population. Most existing ATFs are equipped with unique sized straight cylindrical earcanals, considered representative of average human morphology, and are therefore unable to assess how earplugs can fit different earcanal morphologies. In this study, a methodology to cluster earcanals as a function of their morphologies with the objective of designing artificial ears dedicated to sound attenuation measurement is developed and applied to a sample of Canadian workers’ earcanals. The earcanal morphologic indicators that correlate with the attenuations of six models of commercial …

การสังเคราะห์และการอบฟิล์มบาง Vo2 ที่ปลูกด้วยกระบวนการโซลเจลเพื่อนำไปใช้เป็นกระจกกันความร้อนอัจฉริยะ, พงศธรณ พันธ์บูรณะ

Chulalongkorn University Theses and Dissertations (Chula ETD)

ผู้ทดลองทำการทดลองเพื่อหาเงื่อนไขที่เหมาะสมสำหรับการปลูกฟิล์มบาง VO2 (M) ที่มีสมบัติ Semiconductor Metal transition (SMT) ซึ่งสามารถนำไปใช้ในการทดลองและใช้เป็นอุปกรณ์ต่างๆ เช่นกระจกกันความร้อนอัจฉริยะ (Smart Window) ผู้ทดลองปลูกฟิล์มบาง VO2 (M) ด้วยกระบวนการโซลเจลซึ่งเป็นวิธีที่มีความซับซ้อนไม่มากและค่าใช้จ่ายต่ำกว่าวิธีอื่น การทดลองนี้ศึกษาผลของตัวแปรทั้ง 5 ต่อการอบฟิล์มบาง VO2 ซึ่งตัวแปรทั้ง 5 ประกอบด้วย อุณหภูมิ เวลา บรรยากาศในขณะอบฟิล์ม ซับสเตรตและสารตั้งต้นที่ใช้ในการอบฟิล์ม ผู้ทดลองปลูกฟิล์มภายใต้อุณหภูมิต่างๆ (300, 400 และ 500 °C) และอบฟิล์มด้วยเวลาที่ต่างกัน (30, 60, 90 และ 120 นาที) ภายใต้บรรยากาศปกติและบรรยากาศที่มีออกซิเจนน้อย (ไนโตรเจนหรืออาร์กอน) การทดลองนี้ใช้ซับสเตรตสองชนิด (SiO2 และ Al2O3) และใช้สารตั้งต้นสองชนิด สารตั้งต้นชนิดแรกคือ VO(OC3H7)3 ที่มีอัตราส่วน V:O 1:4 และ เริ่มต้นด้วย V5+ สารตั้งต้นชนิดที่สองคือ VO(acac)2 ที่มีอัตราส่วน V:O 1:5 และ เริ่มต้นด้วย V4+ จากนั้นผู้ทดลองได้ตรวจสอบสมบัติและชนิดของฟิล์มด้วยการวัดความต้านทานที่อุณหภูมิต่างๆ ก่อนและหลังอบฟิล์ม ตรวจสอบโครงสร้างของฟิล์มโดยรามานสเปกโตรมิเตอร์และการวิเคราะห์การเลี้ยวเบนของรังสีเอกซ์ การทดลองให้ผลว่าอุณหภูมิที่สูงกว่าและเวลาที่นานกว่าในการอบทำให้ฟิล์มที่ได้มีสมบัติเข้าใกล้ VO2 (M) มากกว่าการใช้อุณหภูมิและเวลาในการอบที่น้อยกว่า นอกจากนั้นผู้ทดลองยังพบว่าเงื่อนไขที่เหมาะสมสำหรับการปลูกฟิล์มคือ การใช้ Al2O3 เป็นซับสเตรตโดยมี VO(OC3H7)3 เป็นสารตั้งต้นและทำการอบในบรรยากาศที่มีออกซิเจน น้อย ในการทดลองสุดท้ายผู้ทดลองปลูกฟิล์มบน Al2O3 โดยใช้ VO(OC3H7)3 เป็นสารตั้งต้นแล้วทำการอบที่อุณหภูมิ 500 °C นาน 120 นาที ภายใต้บรรยากาศที่มีออกซิเจนเป็นส่วนประกอบน้อย (อาร์กอน) ผลการวิเคราะห์การเลี้ยวเบนของรังสีเอกซ์และการใช้รามานสเปกโตรมิเตอร์ยืนยันว่าฟิล์มที่ได้เป็น VO2 (M) ที่ปนด้วย V6O13 ซึ่งมีสมบัติ SMT ที่ 79 °C และสามารถกั้นรังสีอินฟราเรดที่อุณหภูมิสูงได้เล็กน้อย …

Stability Of A Discrete-Time Infected-Aged Epidemic Model, Patchara Ploypetch

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this thesis, we consider a discrete-time infected-aged SIS epidemic model. The model is obtained from a continuous-time SIS epidemic model by applying Micken’s nonstandard finite difference method. We derive some basic properties of solutions including the boundedness and positivity of solutions. Furthermore, we obtain two parameters R0 and R∞ so that if R0 < 1 then the infection becomes extinct whereas if R∞ > 1 the the infection becomes permanent.

Developing Test Statistics For Familial Dna Searches Through Classification Ideas, Chanagarn Laoiam

Chulalongkorn University Theses and Dissertations (Chula ETD)

In a familial DNA search, the test statistic used for concluding a relationship is the likelihood ratio. In the traditional way, it is assumed that all individuals have the same genetic background ; however, population substructure typically exists and allele frequencies differ among subpopulations. To address this issue, a number of modified likelihood ratio statistics have been proposed. One is to apply the likelihood ratio framework to the average available allele frequencies (LRLAF). Another well-known three statistics are taking the maximum, minimum and average of all available likelihood ratios (LRMAX, LRMIN or LRAVG, respectively). In this thesis, two new likelihood …

Classification Of Metal Hydride Superconductors Using Machine Learning, Vichayuth Imchitr

Chulalongkorn University Theses and Dissertations (Chula ETD)

Metal hydrides are currently the main approach in the quest for high-temperature superconductors, as they exhibit a wide range of superconducting critical temperatures (TC). The key ingredient for determining the superconducting critical temperature is the phonon in the material. However, calculating the phonon via the first-principle method requires high computational costs and is time-consuming. To expedite the search for new superconducting hydrides, machine learning has been applied to scan for potential high-TC materials before performing phonon calculations. However, this method has limitations due to the limited number of available training samples, and the selection of input features for the task …

Thermodynamic Stability Prediction Of Multi-Transition-Metal Mxenes, Chayanon Atthapak

Chulalongkorn University Theses and Dissertations (Chula ETD)

Over the past decade, the largest group of two-dimensional alloys like transition metal carbides/nitrides (MXenes), have attracted a lot of attention in the material science community due to their alloying behaviors and their wide range of applications. However, the phase stability of multi-transition-metal MXenes has so far barely been validated. For this reason, examinations of the stability of multi-transition-metal MXenes from the theoretical aspect are highly of importance for future experimental synthesis and characterization of the materials. In this work, the proponent aims at investigating the thermodynamic stability of (Mo-Ti-V)3C2 MXenes, by performing computational simulations based on density functional theory …