Honors Projects
Showing 461 - 470 of 662 Items
Examining the role of GRP and LIK1 in Wall Associated Kinase (WAK) perception of pectin in the plant cell wall
Date: 2017-01-01
Creator: Jack Ryan Mitchell
Access: Open access
- Wall associated kinases (WAKs) are cell membrane bound receptor kinases that bind pectin and pectin fragments (OGs).The binding of WAKs to pectin sends a growth signal required for cell elongation and plant development. WAKs bind OGs with higher affinity than native pectin and instead activate a stress response. Glycine rich proteins (GRPs) are secreted cell wall proteins of unknown function. Seven GRPs with 65% sequence similarity are coded on a 90kb locus of Arabidopsis chromosome 2. GRP3 and WAK1 have been shown to bind in vitro, but single null mutations have no discernible phenotype, suggesting that the GRPs are redundant. Low recombination frequency has made multiple mutations difficult to achieve, but in this thesis, CRISPR/Cas9 technology was used to induce deletions of the GRP locus. The promoters pYAO and pICU2 drove Cas9 expression in transformed Arabidopsis plants. The presence of a deletion and Cas9 were detected by PCR. While somatic mutations were induced, there was no inheritance of the GRP deletion, indicating that pYAO and pICU2 do not drive Cas9 to induce deletions in progenitor cells. LIK1 is a CERK1 interacting kinase implicated in mediating response to various microbe associated molecular patterns (MAMP) such as chitin, flagellin, and peptidoglycans. LIK1 exhibits a drastic increase in phosphorylation in response to OG treatment, making it a candidate for a co-receptor to WAK. T-DNA insertions to the 5’UTR of LIK1 were used to examine the effect of a lik1 mutation on the OG induced stress response. lik1/lik1 mutant seedlings were grown in the presence and absence of OGs, and RNA was isolated. qPCR was used on cDNA to examine FADLOX expression, a reporter for the transcriptional response to OGs. The lik1/lik1 mutant caused a reduction in the OG induced transcriptional response. However, increased LIK1 expression was associated with the T-DNA insertion indicating that LIK1 inhibits the WAK stress response pathway. Understanding the roles of GRP and LIK1 in moderating WAK mediated pathogenic response in Arabidopsis will enable a better understanding of plant resistance to pathogen invasion in the greater plant kingdom.
The Ethiopian Student Movement and the Dilemma of Eritrean Sovereignty
Date: 2024-01-01
Creator: Liat G. Tesfazgi
Access: Open access
- From the perspective of Ethiopian royalists, Pan-Africanists, Marxist internationalists, supports of union, and the broader international community, Eritrean nationalism revealed distressing fissures in many different arguments for preserving Ethiopian territorial unity– arguments not necessarily or explicitly problematic, but nevertheless in opposition to Eritrean demands for the right to national self-determination. For the Ethiopian Student Movement (ESM) specifically, Eritrean sovereignty demanded a reconfiguration of Pan-African unity that conflicted with Ethiopian exceptionalist historiography. Through an analysis of student politics at Haile Selassie University, from 1960-1974, this thesis seeks to complicate existing historiography on the ESM by examining the periodically divergent experiences of Eritrean student activists.
Self-Censorsh** in the Classroom This record is embargoed.
- Embargo End Date: 2027-05-14
Date: 2024-01-01
Creator: Sarah Greenberg
Access: Embargoed
Neural compensation in response to salinity perturbation in the cardiac ganglion of the American lobster, Homarus americanus
Date: 2024-01-01
Creator: Josephine P. Tidmore
Access: Open access
- Central pattern generator (CPG) networks produce the rhythmic motor patterns that underlie critical behaviors such as breathing, walking, and heartbeat. The fidelity of these neural circuits in response to fluctuations in environmental conditions is essential for organismal survival. The specific ion channel profile of a neuron dictates its electrophysiological phenotype and is under homeostatic control, as channel proteins are constantly turning over in the membrane in response to internal and external stimuli. Neuronal function depends on ion channels and biophysical processes that are sensitive to external variables such as temperature, pH, and salinity. Nonetheless, the nervous system of the American lobster (Homarus americanus) is robust to global perturbations in these variables. The cardiac ganglion (CG), the CPG that controls the rhythmic activation of the heart in the lobster, has been shown to maintain function across a relatively wide, ecologically-relevant range of saline concentrations in the short-term. This study investigates whether individual neurons of the CG sense and compensate for long-term changes in extracellular ion concentration by controlling their ion channel mRNA abundances. To do this, I bathed the isolated CG in either 0.75x, 1.5x, or 1x (physiological) saline concentrations for 24 h. I then dissected out individual CG motor neurons, the pacemaker neurons, and sections of axonal projections and used single-cell RT-qPCR to measure relative mRNA abundances of several species of ion channels in these cells. I found that the CG maintained stable output with 24 h exposure to altered saline concentrations (0.75x and 1.5x), and that this stability may indeed be enabled by changes in mRNA abundances and correlated channel relationships.
Understanding the Truce of the Irish War of Independence Through Regional Newspaper Editorials
Date: 2025-01-01
Creator: Janet Elizabeth Briggs
Access: Open access
Characterizing the organizational/activational role of ovarian hormones in the mediation of
adversity-induced anxiety in female rats Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2025-01-01
Creator: Cassidy J. Scott
Access: Access restricted to the Bowdoin Community
Random Walks on Finite Groups: an
Application of Group Representations
Date: 2025-01-01
Creator: David Guan
Access: Open access
- Playing cards, a set of fifty-two cards with four suits and thirteen numbers, appear every- where in ourdaily lives. In particular, theyare commonly used ongambling tables in casinos. Before every game, the dealer needs to shuffle those cards to put them into a random order so that the game is fair. (Is it really the case in casinos?) One may wonder whether a shuffling technique is really efficient or not, i.e. whether it can turn the deck into a random configu- ration in a small number of rounds. Mathematically, this can be interpreted as a problem of random walks on the symmetric group of 52 elements S_{52} and we aim to determine how fast the random walk becomes (uniformly) random. This paper aims to explain an important application of group representations to this type of problems; in particular, techniques from group representations can provide a (roughly) accurate approximation. There will be six chapters in this paper. Chapter 1 is an introduction to problems of random walks. Chapter 2 and 3 discuss group representations in general, and a key lemma for application is discussed at the end of Chapter 3. Chapter 4 is an application to the easiest random walk one can encounter. Chapter 5 focuses on discussing properties distinctive to symmetric groups, and Chapter 6 discusses a card-shuffling example in details. Contents in Chapter 5 are mostly from the second chapter of [Sag01]; the key result in Chapter 6 along with the rest of the paper are mostly from [Dia88] with a few exceptions. This paper is written in a self-explanatory way, so anyone with necessary background of linear algebra, group theory, and probability will be able to follow the entirety of it.
Exploring the Effect of Core Tactics and Demographics on Squash
Gameplay Patterns Using Computer Vision
Date: 2025-01-01
Creator: Abhiroop Reddy Nagireddygari
Access: Open access
- This paper presents a computer vision system for analyzing common tactical and training pat- terns in squash using player locations and movement dynamics. Leveraging convolutional neural networks (CNNs) such as YOLO and TrackNet, we extract player coordinates on a squash court through a lightweight, single-camera framework. Match footage and detections are segmented by gender, skill level, and match phase to enable contextual comparisons. From 2D coordinates, we generate heatmaps of player locations, court coverage percentages, and distance-over-time graphs to visualize movement tendencies. Our results show that women demonstrate greater ball control and accuracy than men across all levels, while professional players exhibit more aggressive court usage than amateurs. We also identify that games 2 and 3 are the most physically demanding, highlighting a balance between slow starts and fatigue.
Tree Level Amplitudes for Yang-Mills and Complex Scalar Field Theory using Perturbiner Methods
Date: 2025-01-01
Creator: Abigail R. Chriss
Access: Open access
Associations between Autistic Camouflaging, Autistic Burnout, Authenticity, and Mental Health Challenges: Exploring A Mediation Model Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2025-01-01
Creator: Yaerin H. Wallenberger
Access: Access restricted to the Bowdoin Community