Life Sciences Commons^™

Reviewing Research On Down Syndrome To Then Inform And Create A Children’S Book With A Child Protagonist Who Has Down Syndrome, Trey Williams

Honors Projects

Children's literature continually evolves, requiring a steadfast commitment to align with new insights into various disabilities for genuine and accurate portrayal. This project delves into leveraging research to craft a children's book featuring Bonnie Lynn, a protagonist with Down Syndrome, recognizing the growing presence of individuals with Down Syndrome in today's society and the imperative for empathetic understanding within this community.

Visual Cortical Traveling Waves: From Spontaneous Spiking Populations To Stimulus-Evoked Models Of Short-Term Prediction, Gabriel B. Benigno

Electronic Thesis and Dissertation Repository

Thanks to recent advances in neurotechnology, waves of activity sweeping across entire cortical regions are now routinely observed. Moreover, these waves have been found to impact neural responses as well as perception, and the responses themselves are found to be structured as traveling waves. How exactly do these waves arise? Do they confer any computational advantages? These traveling waves represent an opportunity for an expanded theory of neural computation, in which their dynamic local network activity may complement the moment-to-moment variability of our sensory experience.

This thesis aims to help uncover the origin and role of traveling waves in the …

Assessing Threats To Plant Populations: Linking Pollinator Differences To Patterns Of Plant Fitness And Population Genetics, Rieka Yu

Dissertations

Land use change is a major driver of biodiversity loss and consequently has led to the loss of genetic diversity in many plant populations due to declines in population sizes and an increase in spatial isolation. However, not all plant populations respond similarly to land-use change, suggesting there are additional mechanisms mediating plant population genetic patterns. Here, I examine the role of pollinators as this mediating factor. In Chapter 1 I conducted a meta-analysis to investigate how different types of pollinators drive changes in gene flow for plant populations in disturbed habitats, finding that different types of pollinators mediate different …

Changes In Peatland Soil Fauna Biomass Alter Food Web Structure And Function Under Warming And Hydrological Changes, Trevor L. Pettit

Electronic Thesis and Dissertation Repository

Short-term climate perturbations affect both predator and prey species that comprise soil communities, and alter carbon flux. I used a mesocosm experiment to model the effects of experimentally-imposed temperature and moisture conditions that simulate potential future conditions during climate perturbations, on peatland soil food web flux and soil carbon sequestration after three-weeks of experimentally imposed conditions, and then again after an additional three-week recovery under control conditions. I compared system resistance and resilience, and modelled carbon (C) and nitrogen (N) fluxes throughout the mesocosm experiment. There was a lack of resistance of the soil food web to perturbation shown by …

The Role Of The Mek1/2-Erk-Rsk Signalling Axis In Innate Immune Memory, Rachel Low

Electronic Thesis and Dissertation Repository

Macrophages are innate immune cells that change their cellular states in response to different stimuli. This process is referred to as “innate immune memory” which can render two polarizing states: hyporesponsive (tolerated) or hyperresponsive (trained) states. To date, epigenetic modifications were shown to play a key role in innate immune memory. However, the signalling that induces memory is poorly understood. In this study, I examined the effects of various inhibitors targeting key signalling molecules involved in the activation of macrophages by the Gram-negative cell wall component lipopolysaccharide. I found that prolonged inhibition of the MEK1/2-ERK-RSK signalling axis prevented tolerance and …

Impact Of Retinoic Acid Receptor Alpha Conditional Knockout On Ovarian Follicle Development In The Mouse, Zlata Bogin

College of Science and Health Theses and Dissertations

When there is abnormal endocrine signaling in the follicles, infertility, and ovarian diseases such as polycystic ovarian syndrome (PCOS), premature ovarian failure (POF), and different types of ovarian cancers may occur. Retinoic acid (RA), a biologically active derivative of vitamin A, is a critical signaling molecule that plays a vital role in various physiological processes, including embryonic development, tissue differentiation, and reproductive function. RA has been observed to influence granulosa cell proliferation through a cell signaling cascade involving Retinoic Acid Receptors (RARs), which have three isoforms alpha, beta, and gamma. We characterized a new retinoic acid receptor alpha (RARA) conditional …

Investigating The Salinity Tolerance Of The Swordtail (Xiphophorus Hellerii), Alexandra Megan Krak

College of Science and Health Theses and Dissertations

The swordtail, Xiphophorus hellerii, is a freshwater fish species native to Mexico and Central America and is commonly used in the tropical aquarium trade. Swordtails have been shown to have limited survival in 6 ‰ salinity (Nanda et al., 2016), suggesting they may have a greater salinity tolerance than previously expected. Using a gradual acclimation method, we examined the salinity tolerance and swim performance of this species. Freshwater-reared female swordtails were housed in 29-gallon aquaria. A control group was held in freshwater throughout the experiment. For the experimental group, the salinity was increased by 2 ‰ every week until 30 …

Characterization Of The Immune Deficiency Pathway During Female Meiosis In Drosophila Melanogaster, Sarah Mashburn

College of Science and Health Theses and Dissertations

Organisms can defend against pathogens by significantly increasing the diversity of their progeny, so that some progeny are more likely to survive infection. This led to the prediction that infection should cause an increase in recombination rates which was seen in a previous study. However, the mechanism that regulates recombination rates in response to infection is not understood and in that study they did not provide a mechanism for how that can occur. In an RNAi screen, our lab found the gene mustard (mtd) is required for normal recombination rates. This gene was previously shown to be part of the …

Observations Of 25 Ghz Methanol Masers In W51a, Peter Wagstaff

College of Science and Health Theses and Dissertations

High mass stars are important because they alone are responsible for creating the heavy elements in the Universe. The observation of high mass star formation remains a challenging problem in astronomy because high mass stars form in densely clustered environments at large distances from us. Therefore, high angular resolution observations are required to unravel the action taking place in these dense environments. Masers can be used to observe distant regions with high angular resolution because masers are compact and bright sources. Class I methanol masers are believed to form in outflows from protostars where the shock generated by the outflowing …

Neural Dynamics Of Visual Processes In Challenging Visibility Conditions, Saba Charmi Motlagh

Electronic Thesis and Dissertation Repository

In our daily visual experience, our brain effortlessly categorizes countless objects, enabling us to perceive and interpret the world around us. This core object recognition process is vital for our survival and adaptive behavior, allowing us to recognize objects despite variations in appearance. The incredible speed at which we accomplish this task is a testament to the efficiency of our visual system and the significance of visual processing is evident in the allocation of nearly half of the neocortex in primates to this function. Unraveling the intricacies of how the human visual system tackles this complex challenge has long been …

Effects Of Wilting Extent On The Phytoestrogen Levels, Nutritional Value, Microbial Populations, And In Vitro Ruminal Methane Emissions Of Red Clover Hay And Silage Across Stages, Diego Zamudio Ayala

Electronic Theses and Dissertations

The main objective of this thesis is to improve the understanding and awareness of methodologies to decrease phytoestrogens in conserved legumes without sacrificing forage nutritive value. In chapter 1, we discussed the main factors influencing each stage of hay production and our current understanding of the hay microbiome dynamics. The primary objective of haymaking is to dry forage enough (80-85% DM) to inhibit the growth of undesirable microbes and halt residual plant enzymatic activity that causes nutrient losses. During the field and storage phases of haymaking, the environment, management practices, and other factors influence the extent of DM losses. This …

Scaled Ecology: A Framework For Evaluating Conservation Of Wildlife Ecological Processes, Johanna A. Hodge

Biology Theses, Dissertations, and Student Creative Activity

Ecological processes are scaled in time and space, including those associated with wildlife. Understanding the ecological processes of wildlife species and their contributions to ecosystems is crucial for effective conservation. This study focuses on American bison (Bison bison) as a case-study species to explore the holistic scaling of wildlife ecology. A PRISMA-style literature review was conducted to gather and map the scaled ecology of bison. An AIC best-fit analysis was conducted to assess the scaling of total bison ecology considering 7 different models. The results rejected the null model and identified the best-fit model as a combination between fencing and …

The Influence Of Framing And Recent Experience On Farmer Choices In Experimental Games Depicting Risk-Reducing Agricultural Technologies, Ana Maria Ospina Tobar

Electronic Theses and Dissertations

Climate change is a major threat to food security, particularly in low and middle-income countries that are highly dependent on staple crops for subsistence. The vulnerability of staple crops, like maize, in the face of climate change, is increasing due to the increasing frequency of droughts. This thesis aims to evaluate two mechanisms through which farmers may be more willing to adopt new technologies that increase their resilience to climate change: First, I evaluate the effectiveness of a new virtual maize farming game as a learning tool to teach farmers about the outcomes they could obtain under different weather events …

Using Mesocosms To Model Optimal Levels Of Body Size Variation In Larval Spotted Salamanders (Ambystoma Maculatum), Ian Kratzer

Online Theses and Dissertations

Body size is a critical aspect of an organism’s biological identity mediated by various biotic and abiotic factors. Body size historically been approached through “single optima” approaches, but body size variation modifies both inter- and intraspecific interactions and impacts competition-driven fitness outcomes within populations. Understanding optimal levels of body size variation will help illuminate how variation influences competitive outcomes and reproductive fitness. Populations may be structured through resource partitioning or competitive hierarchies, yet these structures predict contradictory size variation optima. This study sought to determine optimal levels of intraspecific body size variation in populations of larval salamanders to evaluate these …

Collaborative And Engaged Research To Strengthen Equity And Adaptive Governance In Co-Managed Fisheries, Gabrielle V. Hillyer

Electronic Theses and Dissertations

Small-scale, co-managed fisheries are found throughout the world and often represent intertwining cultures, societies, communities, economies, institutions, and governments. They face complex issues, derived from ecological and social sources. Solving these issues requires diverse expertise, often developed through engaged methodologies which can facilitate collaborative solution creation between researchers, community members, and others. In this dissertation, I demonstrate the benefits of these engaged methodologies and review how they, when coupled with anticolonial approaches to research, can create more equitable solutions to complex issues. This dissertation focuses on multiple projects within the wild clam fishery in Maine including: (1) the creation of …

Exploring The Impact Of Pqn-75 And Glh-1/Vasa On Germline Development, Maintenance, And Gsc Reprogramming Using Caenorhabditis Elegans As A Model, Jesse D. Rochester

Electronic Theses and Dissertations

This thesis combines research on PQN-75 expression, functional motifs of GLH-1/Vasa, and germ granule components in Caenorhabditis elegans to provide a comprehensive understanding of germline development, maintenance, and reprogramming, while also examining the role of pharyngeal gland cells in stress resistance and thermotolerance. In C. elegans, pharyngeal gland cells secrete mucin-like proteins, such as PQN-75, with similarities to human PRB2. The expression of PQN-75 in gland cells confers stress resistance and thermotolerance but does not affect fertility, instead it plays a role in the organism's ability to adapt to varying environmental conditions. While, GLH-1/Vasa, an ATP-dependent DEAD-box helicase, plays …

Integrating Environmental Dna, Traditional Fisheries Techniques, And Species Distribution Modeling To Assess Bridle Shiner Status In Maine, Lara S. Katz

Electronic Theses and Dissertations

The bridle shiner (Notropis bifrenatus) is a small minnow species native to the eastern United States and southeastern Canada. The species is declining dramatically throughout most of its native range and has legal protection or concern status in thirteen states and two Canadian provinces. In Maine, the bridle shiner is listed as a Species of Special Concern and considered a Species of Greatest Conservation Need, partially because we lack a basic understanding of their status and distribution within the state. Bridle shiners have historically been found in southern and western Maine in densely vegetated, shallow habitats along the …

Climate Interactions Drive Tree Physiology And Growth In A Northeastern Forest Ecotone, Alexandra M. Barry

Electronic Theses and Dissertations

Climate change is a threat to global forest ecosystems. In the northeastern United States, forest trees are facing rising temperatures and increasingly inconsistent moisture regimes. In addition to long-term changes in climate conditions, there is concern about the potential for more frequent and intense climate extremes, which can have severe and rapid negative effects on tree physiology and growth. Further, climate extremes may co-occur to produce a greater magnitude of effect than the sum of their parts, with a prominent example being hot droughts, which are increasing in occurrence and severity. The impact of these and other extreme climate interactions …

A Quantitative Visualization Tool For The Assessment Of Mammographic Risky Dense Tissue Types, Margaret R. Mccarthy

Electronic Theses and Dissertations

Breast cancer is the second most occurring cancer type and is ranked fifth in terms of mortality. X-ray mammography is the most common methodology of breast imaging and can show radiographic signs of cancer, such as masses and calcifcations. From these mammograms, radiologists can also assess breast density, which is a known cancer risk factor. However, since not all dense tissue is cancer-prone, we hypothesize that dense tissue can be segregated into healthy vs. risky subtypes. We propose that risky dense tissue is associated with tissue microenvironment disorganization, which can be quantified via a computational characterization of the whole breast …

The Role Food Security, Financial Literacy, And Nutrition Literacy Play On The Diet Quality Of College Students, Amelia Sullivan

Electronic Theses and Dissertations

This research aimed to explore the roles of food security status (FSS), financial literacy (FL), and nutrition literacy (NL) on the diet quality (DQ) of college students at the University of Maine. This research additionally sought to understand mediational relationships among these factors that could impact DQ.

A cross-sectional convenience sample of college students completed an online questionnaire assessing sociodemographic factors, short healthy eating index (sHEI)-score, FSS, FL, and NL. Participants' continuous data were analyzed using a Pearson correlation. Differences between interactive NL and sHEI-score while controlling for gender and meal plan differences were analyzed using a MANCOVA. Additionally, differences …

Effects Of Large Wood Additions On Basal Resources, Macroinvertebrates, And Ecosystem Processes In The Narraguagus River, Maine, Val Watson

Electronic Theses and Dissertations

Ecological restoration is an increasingly common practice across ecosystems, and current practices aim to restore the biological and physical processes underlying ecosystem function, often for the sake of endangered higher-level consumers. Studies of restoration outcomes often report few or inconsistent ecological changes, and monitoring of restoration projects rarely measures ecological processes. Monitoring also usually measures outcomes at a single scale, despite the prevalence of scale- dependent phenomena across ecosystems. My thesis uses measurements of ecological processes to assess restoration response and evaluates responses across multiple scales. I focus here on a long-term large wood addition project on the Narraguagus River …

Muscle Defects Lead To Skeletal Deformities In A Zebrafish Model Of Distal Arthrogryposis, Emily A. Tomak

Electronic Theses and Dissertations

Distal Arthrogryposis Type 1 (DA1) involves mild muscle weakness and limb skeletal abnormalities thought to be caused by paralysis in utero. Why the limbs are particularly affected in DA1 and the degree of paralysis that leads to these skeletal deformities in utero remains unclear. Several muscle genes are known to cause DA1, including MYLPF (myosin light chain phosphorylatable), which encodes a myosin light chain protein that binds close to the force-generating head of myosin heavy chains. The zebrafish mylpfa^-/- mutant displays a phenotype consistent with DA1, including impaired myosin activity, reduced muscle force overall, and complete fin paralysis. I …

The Relationship Between Intuitive Eating And Body Mass Index And Diet Quality In College Students, Ashley A. Reynolds

Electronic Theses and Dissertations

Objective

The objective of this research was to explore the influence of intuitive eating (IE) on body mass index (BMI) and diet quality (DQ) among college students.

Methods

A cross-sectional convenience sample of college students completed an online survey consisting of the short-Healthy Eating Index (SHEI) and the Intuitive Eating Scale-2 (23 items). Body mass index was calculated using self-reported height and weight. Descriptive statistics were used to assess group characteristics. A linear regression was used to test if IE scores significantly predicted BMI. An independent t-test was used to compare BMIs of students with IE scores above and below …

Chef Sensory Perspectives And Consumer Acceptance Of Fermented Green Crab Sauce, Bryson J. Mcdonough

Electronic Theses and Dissertations

The European green crab (Carcinus maenas) is an invasive species responsible for immense ecological and economic damage along the Northeastern coast of the United States. Despite multiple population control methods explored, intensive indiscriminate trapping has been the only effective approach However, this type of trapping is currently not financially viable because of the low price and demand for hard-shell green crabs due to their small size and difficult-to-extract crabmeat.

To address this issue, researchers have investigated green crab sauce, a fermented condiment inspired by fish sauce. This umami-enhancing condiment has the potential to raise hard-shell green crab value …

Cellulose Nanocrystals/Polydimethylsiloxane Composite Membranes For Air Dehydration With The Aim Of Energy-Use Reduction In Wood Kiln Drying, Nasim Alikhani

Electronic Theses and Dissertations

This dissertation project addressed the manufacture and evaluation of a small polydimethylsiloxane (PDMS) hollow fiber membrane system in the kiln drying of lumber in an attempt to explore air dehydration and reduced energy usage. Temperature and vacuum pressure exert the most pronounced influence on membrane efficiency. Under optimal conditions, the PDMS membrane module demonstrates a remarkable 66% efficiency in removing water vapor from a moist air stream. Based on the parameters of the lab system and its operational performance, a finite element model was developed to simulate its scaleup for a lab-scale lumber drying kiln to remove moisture from the …

A Small Molecule Screen On Zebrafish Embryos Identifies Pathways Vital To Hypaxial Muscle Precursor Migration, Teresa Easterbrooks

Electronic Theses and Dissertations

Hypaxial muscles form through long-range migration of muscle precursor cells (MMPs) from the somites. In zebrafish, the MMPs migrate in three compact streams to generate four muscles - the sternohyoideus muscle, homologous to mammalian neck and tongue; the posterior hypaxial muscle; and the two pectoral fin muscles, homologous to mammalian limbs. Several factors, such as Six1/4, are known to promote this migration; however, many aspects of guidance, pathing, and modulation of these streams are still unknown. To fill this gap, we conducted a small-molecule screen. This pharmacological approach allows us to identify molecules that cause pronounced changes in the normal …

"The Trees Act Not As Individuals"--Learning To See The Whole Picture In Biology Education And Remote Sensing Research, Rebeka A.F. Greenall

Theses and Dissertations

To increase equity and inclusion for underserved and excluded Indigenous students, we must make efforts to mitigate the unique barriers they face. As their knowledge systems have been historically excluded and erased in Western science, we begin by reviewing the literature on the inclusion of Traditional Ecological Knowledge (TEK) in biology education and describe best practices. Next, to better understand how Native Hawaiian and other Pacific Islander (NHPI) students integrate into the scientific community, we used Social Influence Theory as a framework to measure NHPI student science identity, self-efficacy, alignment with science values, and belonging. We also investigated how students …

Endothelial Interleukin-17 Receptor D (Il17rd) Promotes Western Diet-Induced Aortic Myeloid Cell Infiltration, Shivangi Pande

Electronic Theses and Dissertations

The Interleukin-17 (IL17) family is a group of cytokines implicated in the etiology of several inflammatory diseases. Interleukin-17 receptor D (IL17RD), also known as Sef (similar expression to fibroblast growth factor), belonging to the family of IL17 receptors, has been shown to modulate IL17A-associated inflammatory phenotypes. The objective of this study was to test the hypothesis that IL17RD promotes endothelial cell activation and consequent monocyte adhesion. We utilized primary human aortic endothelial cells and demonstrated that RNAi targeting of IL17RD suppressed transcript levels by 83% compared to non-targeted controls. Further, RNAi knockdown of IL17RD decreased the adhesion of THP-1 cells …

Predicting Marine Teleost Responses To Ocean Warming And Pollution, Akila Harishchandra

Electronic Theses and Dissertations

Ocean warming and pollution are two detrimental anthropogenic factors causing rapid marine ecosystem degradation recorded in the past decades. These factors alter the marine environment intolerable for many marine species, forcing them to either adapt or shift their contemporary habitat ranges to reduce the extinction risk embedded with environmental degradation. Estimating marine species’ habitat range shifts, and their potential for developing adaptive mechanisms are critical for ecosystem conservation and management, human health risk assessment, and climate change vulnerability assessments. Given that, for the first chapter of this thesis, we focused on developing a species distribution model (SDM) integrating marine species …

Genetic Effects Of Anthropogenic Disturbance On Native Charrs, Brad Erdman

Electronic Theses and Dissertations

Artificial propagation has been utilized for over a century to offset anthropogenic declines of abundance for many fishes. Complex and poorly documented histories of habitat degradation and stockings have resulted in considerable uncertainty regarding whether contemporary populations are of native, hatchery, or mixed origins. This uncertainty is problematic as it precludes prioritizing the conservation of native populations that are postulated to possess local adaptations and greater evolutionary potential. Population genetics can assess the relative reproductive contributions of previous stocking events and in this dissertation I apply these methods to four empirical studies of native charr (genus Salvelinus) that have …