Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

Discipline
Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 66571 - 66600 of 294596

Full-Text Articles in Physical Sciences and Mathematics

Towards An Instant Structure-Property Prediction Quality Control Tool For Additive Manufactured Steel Using A Crystal Plasticity Trained Deep Learning Surrogate, Yuhui Tu, Zhongzhou Liu, Luiz Carneiro, Caitriona M. Ryan, Andrew C. Parnell, Sean B. Leen Jan 2022

Towards An Instant Structure-Property Prediction Quality Control Tool For Additive Manufactured Steel Using A Crystal Plasticity Trained Deep Learning Surrogate, Yuhui Tu, Zhongzhou Liu, Luiz Carneiro, Caitriona M. Ryan, Andrew C. Parnell, Sean B. Leen

Research Collection School Of Computing and Information Systems

The ability to conduct in-situ real-time process-structure-property checks has the potential to overcome process and material uncertainties, which are key obstacles to improved uptake of metal powder bed fusion in industry. Efforts are underway for live process monitoring such as thermal and image-based data gathering for every layer printed. Current crystal plasticity finite element (CPFE) modelling is capable of predicting the associated strength based on a microstructural image and material data but is computationally expensive. This work utilizes a large database of input–output samples from CPFE modelling to develop a trained deep neural network (DNN) model which instantly estimates the …

Go to article

A Drone-Based Application For Scouting Halyomorpha Halys Bugs In Orchards With Multifunctional Nets, Francesco Betti Sorbelli, Federico Coro, Sajal K. Das, Emanuele Di Bella, Lara Maistrello, Lorenzo Palazzetti, Cristina M. Pinotti Jan 2022

A Drone-Based Application For Scouting Halyomorpha Halys Bugs In Orchards With Multifunctional Nets, Francesco Betti Sorbelli, Federico Coro, Sajal K. Das, Emanuele Di Bella, Lara Maistrello, Lorenzo Palazzetti, Cristina M. Pinotti

Computer Science Faculty Research & Creative Works

In this work, we consider the problem of using a drone to collect information within orchards in order to scout insect pests, i.e., the stink bug Halyomorpha halys. An orchard can be modeled as an aisle-graph, which is a regular and constrained data structure formed by consecutive aisles where trees are arranged in a straight line. For monitoring the presence of bugs, a drone flies close to the trees and takes videos and/or pictures that will be analyzed offline. As the drone's energy is limited, only a subset of locations in the orchard can be visited with a fully charged …

Go to article

Graph Neural Networks For Improved Interpretability And Efficiency, Patrick Pho Jan 2022

Graph Neural Networks For Improved Interpretability And Efficiency, Patrick Pho

Electronic Theses and Dissertations, 2020-2023

Attributed graph is a powerful tool to model real-life systems which exist in many domains such as social science, biology, e-commerce, etc. The behaviors of those systems are mostly defined by or dependent on their corresponding network structures. Graph analysis has become an important line of research due to the rapid integration of such systems into every aspect of human life and the profound impact they have on human behaviors. Graph structured data contains a rich amount of information from the network connectivity and the supplementary input features of nodes. Machine learning algorithms or traditional network science tools have limitation …

Go to article

First And Third Order Susceptibility Of Organic Molecules, Hao-Jung Chang Jan 2022

First And Third Order Susceptibility Of Organic Molecules, Hao-Jung Chang

Electronic Theses and Dissertations, 2020-2023

Illuminating a material with intense laser excitation may change its properties and result in nonlinear absorption (NLA) and nonlinear refraction (NLR). In this dissertation we study the nonlinear absorption of organic compounds, the effect of extremely nondegenerate NLR in semiconductors, and the linear refractive index of organic solvents. In liquids, the refractive index has been studied for decades and different kinds of refractometers have been proposed. However, most of the reported values are in the visible region and only for commonly used solvents. We proposed a new interferometer-based refractometer that allows us to measure the refractive index from the visible …

Go to article

Synergistic Impacts Of Climate Change And Human Induced Stressors On The Apalachicola Bay Food Web, Kira Allen Jan 2022

Synergistic Impacts Of Climate Change And Human Induced Stressors On The Apalachicola Bay Food Web, Kira Allen

Electronic Theses and Dissertations, 2020-2023

Apalachicola Bay, an estuary located in northwest Florida, is likely to experience an increase in climate change and human-induced stressors, such as sea level rise and changes in freshwater inflow, in the future. A coupled hydrodynamic and food web modeling approach was used to simulate future scenarios of low and high river flow and sea level rise in Apalachicola Bay from 2020 to 2049 and demonstrate the range of temporal and spatial changes in water temperature, salinity, fisheries species populations and the broader food web. Concurrent with model development, a survey of Apalachicola Bay stakeholders was conducted to assess stakeholder …

Go to article

Third Order Nonlinear Optics In Solids, Nicholas Cox Jan 2022

Third Order Nonlinear Optics In Solids, Nicholas Cox

Electronic Theses and Dissertations, 2020-2023

Nonlinear optical effects occur when strong electromagnetic waves induce changes in a medium that affect its own propagation or that of another wave. Third order optical nonlinearities scale linearly with irradiance and lead to effects like two-photon absorption and nonlinear refraction. This work focuses on the experimental and theoretical study of two-photon absorption in crystalline solids. We begin by detailing the quantum mechanical states of electrons in solids along with the computational approaches to calculate their band structure. Next, a theoretical model for the linear and nonlinear optical interaction of light with matter is presented in a many-body formalism. This …

Go to article

Bayesian Spatiotemporal Modeling With Gaussian Processes, Qing He Jan 2022

Bayesian Spatiotemporal Modeling With Gaussian Processes, Qing He

Electronic Theses and Dissertations, 2020-2023

Bayesian spatiotemporal models have been successfully applied to various fields of science, such as ecology and epidemiology. The complicated nature of spatiotemporal patterns can be well represented through priors such as Gaussian processes. This dissertation is focused on two applications of Bayesian spatiotemporal models: a) anomaly detection for spatiotemporal data with missingness and b) zero-inflated spatiotemporal count data analysis. Missingness in spatiotemporal data prohibits anomaly detection algorithms from learning characteristic rules and patterns due to the lack of most data. This project is motivated by a challenge provided by the National Science Foundation (NSF) and the National Geospatial-Intelligence Agency (NGA). …

Go to article

Improved Reptile Search Optimization Algorithm Using Chaotic Map And Simulated Annealing For Feature Selection In Medical Filed, Zenab Elgamal, Aznul Qalid Md Sabri, Mohammad Tubishat, Dina Tbaishat, Sharif Naser Makhadmeh, Osama Ahmad Alomari Jan 2022

Improved Reptile Search Optimization Algorithm Using Chaotic Map And Simulated Annealing For Feature Selection In Medical Filed, Zenab Elgamal, Aznul Qalid Md Sabri, Mohammad Tubishat, Dina Tbaishat, Sharif Naser Makhadmeh, Osama Ahmad Alomari

All Works

The increased volume of medical datasets has produced high dimensional features, negatively affecting machine learning (ML) classifiers. In ML, the feature selection process is fundamental for selecting the most relevant features and reducing redundant and irrelevant ones. The optimization algorithms demonstrate its capability to solve feature selection problems. Reptile Search Algorithm (RSA) is a new nature-inspired optimization algorithm that stimulates Crocodiles’ encircling and hunting behavior. The unique search of the RSA algorithm obtains promising results compared to other optimization algorithms. However, when applied to high-dimensional feature selection problems, RSA suffers from population diversity and local optima limitations. An improved metaheuristic …

Go to article

Leveraging Natural Language Processing To Analyse The Temporal Behavior Of Extremists On Social Media, May El Barachi, Sujith Samuel Mathew, Farhad Oroumchian, Imene Ajala, Saad Lutfi, Rand Yasin Jan 2022

Leveraging Natural Language Processing To Analyse The Temporal Behavior Of Extremists On Social Media, May El Barachi, Sujith Samuel Mathew, Farhad Oroumchian, Imene Ajala, Saad Lutfi, Rand Yasin

All Works

Aiming at achieving sustainability and quality of life for citizens, future smart cities adopt a data-centric approach to decision making in which assets, people, and events are constantly monitored to inform decisions. Public opinion monitoring is of particular importance to governments and intelligence agencies, who seek to monitor extreme views and attempts of radicalizing individuals in society. While social media platforms provide increased visibility and a platform to express public views freely, such platforms can also be used to manipulate public opinion, spread hate speech, and radicalize others. Natural language processing and data mining techniques have gained popularity for the …

Go to article

Trajectory Design For Uav-Based Data Collection Using Clustering Model In Smart Farming, Tariq Qayyum, Zouheir Trabelsi, Asad Malik, Kadhim Hayawi Jan 2022

Trajectory Design For Uav-Based Data Collection Using Clustering Model In Smart Farming, Tariq Qayyum, Zouheir Trabelsi, Asad Malik, Kadhim Hayawi

All Works

Unmanned aerial vehicles (UAVs) play an important role in facilitating data collection in remote areas due to their remote mobility. The collected data require processing close to the end-user to support delay-sensitive applications. In this paper, we proposed a data collection scheme and scheduling framework for smart farms. We categorized the proposed model into two phases: data collection and data scheduling. In the data collection phase, the IoT sensors are deployed randomly to form a cluster based on their RSSI. The UAV calculates an optimum trajectory in order to gather data from all clusters. The UAV offloads the data to …

Go to article

Haptic Feedback To Assist Blind People In Indoor Environment Using Vibration Patterns, Shah Khusro, Babar Shah, Inayat Khan, Sumayya Rahman Jan 2022

Haptic Feedback To Assist Blind People In Indoor Environment Using Vibration Patterns, Shah Khusro, Babar Shah, Inayat Khan, Sumayya Rahman

All Works

Feedback is one of the significant factors for the mental mapping of an environment. It is the communication of spatial information to blind people to perceive the surroundings. The assistive smartphone technologies deliver feedback for different activities using several feedback mediums, including voice, sonification and vibration. Researchers 0have proposed various solutions for conveying feedback messages to blind people using these mediums. Voice and sonification feedback are effective solutions to convey information. However, these solutions are not applicable in a noisy environment and may occupy the most important auditory sense. The privacy of a blind user can also be compromised with …

Go to article

Explicating Consumer Adoption Of Wearable Technologies: A Case Of Smartwatches From The Asean Perspective, Veerisa Chotiyaputta, Donghee Shin Jan 2022

Explicating Consumer Adoption Of Wearable Technologies: A Case Of Smartwatches From The Asean Perspective, Veerisa Chotiyaputta, Donghee Shin

All Works

This research aims to determine the key antecedent factors in consumers' adoption of and their intention to recommend smartwatch wearable technology. The proposed research model combines the current technology acceptance and innovation diffusion theories with perceived aesthetic and perceived privacy risk to explain individuals' smartwatch adoption and subsequent recommendation to other people. Based on a sample of 299 completed individual online surveys, the research employed partial least squares (a variance-based analysis method) for the model and hypotheses testing. The results showed some similarities as well as differences from the previous literature. The study found that performance expectancy, habit, and perceived …

Go to article

Interacting With Educational Chatbots: A Systematic Review, Mohammad Amin Kuhail, Nazik Alturki, Salwa Alramlawi, Kholood Alhejori Jan 2022

Interacting With Educational Chatbots: A Systematic Review, Mohammad Amin Kuhail, Nazik Alturki, Salwa Alramlawi, Kholood Alhejori

All Works

Chatbots hold the promise of revolutionizing education by engaging learners, personalizing learning activities, supporting educators, and developing deep insight into learners’ behavior. However, there is a lack of studies that analyze the recent evidence-based chatbot-learner interaction design techniques applied in education. This study presents a systematic review of 36 papers to understand, compare, and reflect on recent attempts to utilize chatbots in education using seven dimensions: educational field, platform, design principles, the role of chatbots, interaction styles, evidence, and limitations. The results show that the chatbots were mainly designed on a web platform to teach computer science, language, general education, …

Go to article

A Brief Comparison Of K-Means And Agglomerative Hierarchical Clustering Algorithms On Small Datasets, Hassan I. Abdalla Jan 2022

A Brief Comparison Of K-Means And Agglomerative Hierarchical Clustering Algorithms On Small Datasets, Hassan I. Abdalla

All Works

In this work, the agglomerative hierarchical clustering and K-means clustering algorithms are implemented on small datasets. Considering that the selection of the similarity measure is a vital factor in data clustering, two measures are used in this study - cosine similarity measure and Euclidean distance - along with two evaluation metrics - entropy and purity - to assess the clustering quality. The datasets used in this work are taken from UCI machine learning depository. The experimental results indicate that k-means clustering outperformed hierarchical clustering in terms of entropy and purity using cosine similarity measure. However, hierarchical clustering outperformed k-means clustering …

Go to article

Analysis Of Blockchain Solutions For E-Voting: A Systematic Literature Review, Ali Benabdallah, Antoine Audras, Louis Coudert, Nour El Madhoun, Mohamad Badra Jan 2022

Analysis Of Blockchain Solutions For E-Voting: A Systematic Literature Review, Ali Benabdallah, Antoine Audras, Louis Coudert, Nour El Madhoun, Mohamad Badra

All Works

To this day, abstention rates continue to rise, largely due to the need to travel to vote. This is why remote e-voting will increase the turnout by allowing everyone to vote without the need to travel. It will also minimize the risks and obtain results in a faster way compared to a traditional vote with paper ballots. In fact, given the high stakes of an election, a remote e-voting solution must meet the highest standards of security, reliability, and transparency to gain the trust of citizens. In literature, several remote e-voting solutions based on blockchain technology have been proposed. Indeed, …

Go to article

Multi-Party Contract Management For Microservices, Zakaria Maamar, Noura Faci, Joyce El Haddad, Fadwa Yahya, Mohammad Askar Jan 2022

Multi-Party Contract Management For Microservices, Zakaria Maamar, Noura Faci, Joyce El Haddad, Fadwa Yahya, Mohammad Askar

All Works

This paper discusses the necessary steps and means for ensuring the successful deployment and execution of software components referred to as microservices on top of platforms referred to as Internet of Things (IoT) devices, clouds, and edges. These steps and means are packaged into formal documents known in the literature as contracts. Because of the multi-dimensional nature of deploying and executing microservices, contracts are specialized into discovery, deployment, and collaboration types, capturing each specific aspect of the completion of these contracts. This completion is associated with a set of Quality-of-Service (QoS) parameters that are monitored allowing to identify potential deviations …

Go to article

On The Design And Implementation Of An On-Board Test Bed System For V2v Road Hazard Signaling, Fatma Outay, Faouzi Kamoun, Anouar Chemek, Hichem Bargaoui, Ansar Yasar Jan 2022

On The Design And Implementation Of An On-Board Test Bed System For V2v Road Hazard Signaling, Fatma Outay, Faouzi Kamoun, Anouar Chemek, Hichem Bargaoui, Ansar Yasar

All Works

This paper describes the design, implementation, and testing of an ITS-G5 prototype Road hazard Signaling (RHS) system that is inspired by the concept of crowdsourcing. Our approach enables drivers to interact with a touchscreen onboard interface to send ITS-G5 decentralized environmental notification messages (DENM) in order to warn nearby vehicles against the presence of a hazardous situation. These messages are analyzed, filtered for relevance, and presented to concerned drivers via the Onboard Units (OBUs) so that precautionary measures can be taken. We describe the design and implementation aspects of the proposed system and update the open source cargeo6 implementation of …

Go to article

Comparison Of Reaction Time-Based Collaborative Velocity Control And Intelligent Driver Model For Agent-Based Simulation Of Autonomous Car, Fatma Outay, Abdeljalil Abbas-Turki, Stéphane Galland, Alexandre Lombard, Nicolas Gaud Jan 2022

Comparison Of Reaction Time-Based Collaborative Velocity Control And Intelligent Driver Model For Agent-Based Simulation Of Autonomous Car, Fatma Outay, Abdeljalil Abbas-Turki, Stéphane Galland, Alexandre Lombard, Nicolas Gaud

All Works

Based on historical records, driving in hazardous weather conditions is one of the most serious causes that lead to fatal accidents on roads in general and in United Arab Emirates (UAE) highways in particular. One solution to improve road safety is to equip vehicles and infrastructure with connected and smart devices and convert them into autonomous vehicles. Before deploying a concrete solution to the field, it must be validated by simulation, and more specifically by agent-based simulation. In this paper, we propose to implement the Reaction Time-Based Collaborative Velocity Control (RT-CVC) model that was implemented in autonomous cars into an …

Go to article

On Complete, Horizontal And Vertical Lifts From A Manifold With Fλ (6, 4) Structure To Its Cotangent Bundle, Manisha M. Kankarej, Jai Pratap Singh Jan 2022

On Complete, Horizontal And Vertical Lifts From A Manifold With Fλ (6, 4) Structure To Its Cotangent Bundle, Manisha M. Kankarej, Jai Pratap Singh

All Works

Manifolds with fλ(6, 4) structure was defined and studied in the past. Later the geometry of tangent and cotangent bundles in a differentiable manifold with fλ(6, 4) structure was studied. The aim of the present paper is to study complete, horizontal and vertical lifts from a manifold with fλ (6, 4)-structure to its cotangent bundle.

Go to article

A Novel Tunicate Swarm Algorithm With Hybrid Deep Learning Enabled Attack Detection For Secure Iot Environment, Fatma Taher, Mohamed Elhoseny, Mohammed K. Hassan, Ibrahim M. El-Hasnony Jan 2022

A Novel Tunicate Swarm Algorithm With Hybrid Deep Learning Enabled Attack Detection For Secure Iot Environment, Fatma Taher, Mohamed Elhoseny, Mohammed K. Hassan, Ibrahim M. El-Hasnony

All Works

No abstract provided.

Go to article

Conceptualising The Role Of The Uae Innovation Strategy In University-Industry Knowledge Diffusion Process, Mousa Al-Kfairy, Munir Majdalawieh, Saed Alrabaee Jan 2022

Conceptualising The Role Of The Uae Innovation Strategy In University-Industry Knowledge Diffusion Process, Mousa Al-Kfairy, Munir Majdalawieh, Saed Alrabaee

All Works

Universities are considered one of the primary sources of knowledge and an essential component of the triple helix theory. They fuel the industries with the required expertise and pool of resources to operate efficiently. Moreover, entrepreneurial universities successfully contributed to regional development and employment growth by supporting entrepreneurial activities and incubation programmes. Thus, university-industry collaboration is vital for enhancing knowledge-based industries' knowledge diffusion as well as the regional innovation atmospheres. On the other hand, countries and regional authorities strive to stimulate their regional development by encouraging innovation and entrepreneurship activities. For example, the UAE announced its 2015 innovation strategy that …

Go to article

Classification Of Parkinson Disease Based On Patient’S Voice Signal Using Machine Learning, Imran Ahmed, Sultan Aljahdali, Muhammad Shakeel Khan, Sanaa Kaddoura Jan 2022

Classification Of Parkinson Disease Based On Patient’S Voice Signal Using Machine Learning, Imran Ahmed, Sultan Aljahdali, Muhammad Shakeel Khan, Sanaa Kaddoura

All Works

Parkinson’s disease (PD) is a nervous system disorder first described as a neurological condition in 1817. It is one of the more prevalent diseases in the elderly, and Alzheimer’s is the second most common neurodegenerative illness. It impacts the patient’s movement. Symptoms start gradually with tremors, stiffness in movement, and speech and voice disorders. Researches proved that 89% of patients with Parkinson’s has speech disorder including uncertain articulation, hoarse and breathy voice and monotone pitch. The cause behind this voice change is the reduction of dopamine due to damage of neurons in the substantia nigra responsible for dopamine production. In …

Go to article

Brain Image Fusion Approach Based On Side Window Filtering, Ahmad Al Smadi, Ahed Abugabah, Atif Mehmood, Shuyuan Yang Jan 2022

Brain Image Fusion Approach Based On Side Window Filtering, Ahmad Al Smadi, Ahed Abugabah, Atif Mehmood, Shuyuan Yang

All Works

Brain medical image fusion plays an important role in framing a contemporary image to enhance the reciprocal and repetitive information for diagnosis purposes. A novel approach using kernel-based image filtering on brain images is presented. Firstly, the Bilateral filter is used to generate a high-frequency component of a source image. Secondly, an intensity component is estimated for the first image. Thirdly, side window filtering is employed on several filters, including the guided filter, gradient guided filter, and weighted guided filter. Thereby minimizing the difference between the intensity component of the first image and the low pass filter of the second …

Go to article

Smart Application For Every Car (Saec). (Ar Mobile Application), Murad Al-Rajab, Samia Loucif, Ossama Kousi, Mohamad Bassem Irani Jan 2022

Smart Application For Every Car (Saec). (Ar Mobile Application), Murad Al-Rajab, Samia Loucif, Ossama Kousi, Mohamad Bassem Irani

All Works

Technology is continuously evolving at an exponential rate. Fast technological advances are being made, especially in the field of smart phones, that facilitate the conduct of our daily activities in many areas such as driving. The ever-increasing number of vehicles on roads increases the likelihood of traffic accidents, resulting in higher number of deaths and serious injuries to drivers, passengers, and pedestrians. Among the main causes of road accidents are over speeding, unsafe lane jumping, and failure to keep a safe distance between vehicles, to name a few. In an attempt to contribute to the improvement of road traffic safety, …

Go to article

A Two-Tier Framework Based On Googlenet And Yolov3 Models For Tumor Detection In Mri, Farman Ali, Sadia Khan, Arbab Waseem Abbas, Babar Shah, Tariq Hussain, Dongho Song, Shaker Ei-Sappagh, Jaiteg Singh Jan 2022

A Two-Tier Framework Based On Googlenet And Yolov3 Models For Tumor Detection In Mri, Farman Ali, Sadia Khan, Arbab Waseem Abbas, Babar Shah, Tariq Hussain, Dongho Song, Shaker Ei-Sappagh, Jaiteg Singh

All Works

Medical Image Analysis (MIA) is one of the active research areas in computer vision, where brain tumor detection is the most investigated domain among researchers due to its deadly nature. Brain tumor detection in magnetic resonance imaging (MRI) assists radiologists for better analysis about the exact size and location of the tumor. However, the existing systems may not efficiently classify the human brain tumors with significantly higher accuracies. In addition, smart and easily implementable approaches are unavailable in 2D and 3D medical images, which is the main problem in detecting the tumor. In this paper, we investigate various deep learning …

Go to article

Crowdsensing Application On Coalition Game Using Gps And Iot Parking In Smart Cities, Hasan Abu Hilal, Narmeen Abu Hilal, Ala’ Abu Hilal, Tariq Abu Hilal Jan 2022

Crowdsensing Application On Coalition Game Using Gps And Iot Parking In Smart Cities, Hasan Abu Hilal, Narmeen Abu Hilal, Ala’ Abu Hilal, Tariq Abu Hilal

All Works

This paper provides an overview of crowdsensing and some of its applications. Crowdsensing is a part of the collecting data situations also; it’s built on a data system on multiple customer interactions. Moreover, writing the general information of the smart cities can be used to boost to received number frequency to send messages. This work mentioned the Crowdsensing layers that describe Mobile crowdsensing. The article focuses on crowdsensing layers, developed an application in Coalition Game using crowdsensing in terms of GPS. In addition, this paper discussed the Mobile crowdsensing system and how important the cloud is in serving the wireless …

Go to article

On Modelling And Analyzing Composite Resources’ Consumption Cycles Using Time Petri-Nets, Amel Benna, Fatma Masmoudi, Mohamed Sellami, Zakaria Maamar, Rachid Hadjidj Jan 2022

On Modelling And Analyzing Composite Resources’ Consumption Cycles Using Time Petri-Nets, Amel Benna, Fatma Masmoudi, Mohamed Sellami, Zakaria Maamar, Rachid Hadjidj

All Works

ICT community cornerstones (IoT in particular) gain competitive advantage from using physical resources. This paper adopts Time Petri-Nets (TPNs) to model and analyze the consumption cycles of composite resources. These resources consist of primitive, and even other composite, resources that are associated with consumption properties and could be subject to disruptions. These properties are specialized into unlimited, shareable, limited, limited-but-renewable, and non-shareable, and could impact the availability of resources. This impact becomes a concern when disruptions suspend ongoing consumption cycles to make room for the unplanned consumptions. Resuming the suspended consumption cycles depends on the resources’ consumption properties. To ensure …

Go to article

Environmental Effects On Constructed Wetland Microbial Diversity And Function In The Context Of Wastewater Management, Sandrine Grandmont-Lemire Jan 2022

Environmental Effects On Constructed Wetland Microbial Diversity And Function In The Context Of Wastewater Management, Sandrine Grandmont-Lemire

Cal Poly Humboldt theses and projects

Microbial communities play a crucial role in ecosystems, yet we know little about how microbial diversity influences ecosystem functioning. An important gap in our understanding is how environmental change affects microbial Biodiversity-Ecosystem Function relationships (BEF). These complex interactions between microbial biodiversity and ecosystem function can influence major biogeochemical processes, such as the nitrogen cycle in wetland ecosystems, which play an important role in managing wastewater. To address the effect of biodiversity on function, my study investigates the BEF relationships between microbial diversity and the function in terms of ammonia removal from wastewater at the Arcata Wastewater Treatment Facility (AWTF) both …

Go to article

Tholins: A Gas Phase Computational Study Of Methanimine And Related Species, Bradley T. Chem Jan 2022

Tholins: A Gas Phase Computational Study Of Methanimine And Related Species, Bradley T. Chem

Online Theses and Dissertations

Titan has been referred to as the “gem of the Solar System.” This significance comes from its dense atmosphere, which is the only atmosphere in our Solar System other than Earth’s that is dense enough to produce a hydrological cycle (or methanological cycle, in the case of Titan). Scientists in the fields of astrobiology and astrochemistry believe that Titan’s current atmospheric conditions could resemble that of the primordial Earth, and as such is being studied to further our understanding of how life forms. While Titan’s atmosphere contains an abundance of organic molecules, methanimine (MA) and it’s related species the methyl …

Go to article

Phenotypic Plasticity Of Geographically Central And Peripheral Populations Of Jefferson Salamanders (Ambystoma Jeffersonianum) In Response To Simulated Climate Change, Aaron Devine Jan 2022

Phenotypic Plasticity Of Geographically Central And Peripheral Populations Of Jefferson Salamanders (Ambystoma Jeffersonianum) In Response To Simulated Climate Change, Aaron Devine

Online Theses and Dissertations

Climate change will elicit various species responses as it causes habitats to change. Species with limited dispersal must respond to these changes “in place”, yet some biogeographical hypotheses indicate isolated and less abundant populations experience reduced gene flow and genetic diversity that may limit phenotypic plasticity, contrasting with evidence suggesting more variable habitats select for increased plasticity in peripheral populations. To gain insight into associations between range position and intensity of plasticity, mesocosm experiments were done to assess plasticity in larval growth, size at, and time to, metamorphosis, and survivorship in larval Ambystoma jeffersonianum salamanders from geographically core and peripheral …

Go to article

First Prev Next Last