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Partners in Patterning? Characterizing the Relationship between Bioelectricity and Morphogen Signaling during Zebrafish Axis Formation
No full textThe role of morphogens during embryonic development has been well defined in regulating cell guidance and cell fates through differential concentration gradients. It is also known that differentiated cell types can exhibit different and specific states of membrane potentials (Vmem) known as bioelectric signaling. However, it is less known whether bioelectrics and morphogen signaling intersect in their regulation of cell fate determination during embryogenesis. Using Fluorescent Voltage Reporter (FVR) dyes, patterns of bioelectricity have been characterized across the zebrafish gastrula. These patterns predictably change when embryos are treated with depolarizing (4-aminopyridine) or hyperpolarizing compounds (NMDG-Chloride + Ivermectin). By looking at gene expression patterns using Hybridization Chain Reaction experiments on embryos treated with these compounds, the question of whether morphogen gradients across the zebrafish embryo are influenced by manipulating bioelectric patterns has been investigated. The focus is on the morphogen families most relevant to gastrulation: Fibroblast Growth Factor (FGF), Bone Morphogenetic Protein (BMP), Nodal, Wnt and Sonic Hedgehog (shh). Establishing a connection between bioelectric signaling and morphogen pattern formation will demonstrate how membrane potential differences may be able to influence patterns of these key morphogen families
Temperature and Density Effects on Interactions Between Native Brown Algal Species Fucus vesiculosus and Introduced Red Algal Species Gracilaria vermiculophylla
No full textTemperature plays a significant role in shaping marine ecosystems. Recent rises in the frequency and intensity of marine heatwave (MHW) events and warming oceans associated with climate change necessitate a better understanding of the effects of climatic events on marine organisms. The Gulf of Maine is one of the world\u27s most rapidly warming bodies of water. Interactions among native and introduced macroalgae will be affected by current and future warming; thus, their importance as food and habitat may shift with rising temperatures. Native Fucus vesiculosus has been under threat of displacement by an introduced red alga, Gracilaria vermiculophylla, in some locations. In this study, I investigated inter- and intraspecific interactions of F. vesiculosus and G. vermiculophylla at 15°C and 25°C and two biomass densities. I measured growth rates under various enrichment conditions (ambient, + nutrient enrichment (+N), and + nutrients/+ dissolved inorganic carbon enrichment (+N/+DIC)). Both species showed higher growth rates under 25°C and lower densities, and G. vermiculophylla grew faster than F. vesiculosus across all treatments. Growth did not vary between the ambient and +N treatments; only +N/+DIC resulted in consistently enhanced growth. F. vesiculosus demonstrated an apparent density effect under both intra- and interspecific conditions. In contrast, G. vermiculophylla showed significantly lower growth rates under interspecific pairings, suggesting adverse effects of F. vesiculosus. Grazing preference experiments using dominant gastropods (Littorina littorea and L. obstusata) showed 2X higher combined grazing rates on F. vesiculosus. Thus, while both species may survive under warming water temperatures, higher growth rates by G. vermiculophylla and lower grazing pressure may result in greater success of this introduced species, particularly in dense mats. This may result in a shift in species dominance across the intertidal region, with significant trophic implications
Functionalized PPFPA Films for Tunable Surface Wettability
No full textSurface wettability and surface topography are both known to influence the adhesion of organisms such as bacteria to surfaces. In pursuit of simultaneous control over these two properties, this work seeks to develop surfaces with tunable, reproducible wettability over a continuous range in such a way that preserves nanoscale surface topography. Our approach is to use thin bilayer polymer films. The first layer is poly(allylamine hydrochloride) (PAH), which adheres to both hydrophilic and hydrophobic substrates. The second layer is poly(pentafluorophenyl acrylate) (PPFPA), which bonds covalently to PAH through formation of amide bonds, and is functionalized either before or after deposition with glucamine. We explore how wettability is impacted by the degree of functionalization and whether the PPFPA is functionalized before or after film deposition. The wettability of the polymer films is assessed with dynamic contact angle. Additionally, we explore the feasibility of using pH-dependent contact angle to evaluate the surface functional groups of polymer films
Probing Spatial Reasoning Ability of LLM with Python-Composed Dialogs by SHRDLU
No full textThis thesis assesses GPT-4’s reasoning capabilities by probing it with SHRDLU, a computer program known for its reasoning capabilities that understands and interacts with objects in a virtual “blocks” environment. This project developed a comprehensive dataset comprised of numerous SHRDLU dialogs, which allows for a detailed and quantifiable assessment of GPT-4 capabilities, specifically in spatial reasoning involving containment relationships. The project sets up experiments with different prompting in levels of difficulty to test GPT-4’s understanding of spatial concepts, containment relationships, and its ability to reason through complex scenarios involving object manipulation. The findings reveal that GPT-4 performs well with basic tasks but struggles with complex spatial relationships in a long series of manipulations
Stochastic Processes and their Application in Bayesian Statistics
No full textStochastic processes, one of the most important theories in probability, are the collection of random variables that represent the evolution of their values throughout time. Bayesian statistics is the unified framework for statistical inference that builds on the Bayesian interpretation of probability. Bayesian statistics believe that probability represents our current knowledge about an event of interest. In this paper, we introduce some basic ideas behind stochastic processes and Bayesian statistics and combine these two domains on a CMS hospitalization dataset that concerns the length of hospital stay for patients. Throughout this process, we want to show the usefulness of stochastic processes in Bayesian statistics when we have a non-conjugate prior distribution
Accumulation of Road Salt in a Calcareous Fen: Kampoosa Bog, Western Massachusetts
Get PDFRoad salt poses a threat to the quality of soils and water resources. Wetlands located in salt contaminated areas are at risk of experiencing lower plant and animal species diversity. Therefore, it is critical to understand how modifications to salt application rates and hydrological events impact wetland water quality. Here, we use chloride mass flux, discharge, groundwater chloride concentration, meteorological, and salt application data from 2012– 2020 to estimate chloride accumulation and outflux rates in the Kampoosa Bog subwatersheds, located in Stockbridge and Lee, Massachusetts, and bordered by major highways (Interstate-90 and U.S. Route 7). We also investigate the correlation between wetland size and chloride retention rate. During the 2018–2019 period, mean annual chloride application rates in the major watershed increased from 363000 kg/year (2012–2017) to 479000 kg/ year. This led to a net chloride accumulation (KB100 subwatershed: 339000 kg; KB150 subwatershed: 188000 kg) and increased groundwater chloride concentrations in the fen. Chloride outflux from these subwatersheds was primarily driven by discharge. We found that the relationship between wetland percent cover and chloride retention is complex. Although the percent wetland cover is greater in the KB100 main wetland region compared to the KB150 subwatershed, high precipitation in 2018 resulted in similar chloride retention efficiencies (~26%). During the drier year (2019), chloride retention was higher in the wetland region due to its gentle slopes which promote water accumulation and consequently higher evaporation rates which lowers discharge and chloride outfluxes. The chloride steady-state concentration analysis also suggests that there is potential for chloride accumulation to continue because the watershed has not yet reached steady-state chloride concentrations. Without major modifications to salting practices, chloride concentrations will continue increasing and potentially promote the re-growth of invasives (Phragmites) and continued growth of salt tolerant species (Typha angustifolia/xglauca) that diminish plant diversity
Mobilization
No full text“A diverse and glorious selection . . . a gift of imagination, wit, and wonder. The collection is filled with miniature masterpieces. . . . This must-have anthology is a treasure trove not to be missed.” —Library Journal (starred review)The prestigious annual story anthology, featuring prize-winning stories by Kate DiCamillo, Jess Walter, Dave Eggers, Allegra Goodman, Jai Chakrabarti, Francisco Gonzalez, and more.Continuing a century-long tradition of cutting-edge literary excellence, this year\u27s edition contains twenty prizewinning stories chosen from the thousands published in magazines over the previous year. Guest editor Amor Towles has brought his own refreshing perspective to the prize, selecting stories by an engaging mix of celebrated names and emerging voices. The winning stories are accompanied by an introduction by Towles, observations from the winning writers on what inspired them, and an extensive resource list of magazines that publish short fiction.https://scholarworks.smith.edu/eng_books/1024/thumbnail.jp
Determining Gastrointestinal Parasite Load in Diceros bicornis of the Southern Kalahari Using 18S rRNA Next Generation Amplicon Sequencing The Start of a Longitudinal Study of Nematode Prevalence, Diversity, and Load in a Critically Endangered Rhinoceros Species
No full textSummer Research Fellowship Project Descriptions 2024
Get PDFA summary of research done by Smith College’s 2024 Summer Research Fellowship (SURF) Program participants. Ever since its 1967 start, SURF has been a cornerstone of Smith’s science education. Supervised by faculty mentor-advisors drawn from the Clark Science Center and connected to its eighteen science, mathematics, and engineering departments and programs and associated centers and units. At summer’s end, SURF participants were asked to summarize their research experiences for this publication.https://scholarworks.smith.edu/clark_womeninscience/1014/thumbnail.jp
Electroporation- and Lipofectamine-Mediated Transfection of L3 Brugia malayi Parasites
No full textLymphatic filariasis is a neglected tropical disease that affects millions of people in countries throughout the tropics of Asia, Africa, and the Western Pacific. Caused by Brugia malayi, a mosquito-borne parasitic nematode that enters the human body upon a mosquito’s blood meal, lymphatic filariasis could lead to permanent morbidity with blockage of lymph drainage by the parasites. Current treatment strategies for lymphatic filariasis have limited effects, logistical challenges, and risks of drug resistance. The present study focuses on the biology of B. malayi at the L3 infective stage using reverse genetic techniques. Due to the irreproducibility of past transfection techniques on L3 B. malayi, we aimed to transfect the nematodes using an approach combining electroporation and lipofection to facilitate the delivery of genetic materials through the resistant cuticles of the nematodes. The expression of the transgene, green fluorescence protein (GFP), was assessed using fluorescence microscopy. The transcription of the transgene was further examined using reverse-transcription polymerase chain reaction (RT-PCR) on RNA isolated from transfected B. malayi. Both the fluorescence microscopy results and RT-PCR showed evidence of transient transfection. Green fluorescence was observed in body wall skeletal muscles, corresponding to where the plasmid promoter gene is expressed. RT-PCR results confirm intron splicing of GFP sequences in the transcript. Overall, we demonstrated that transfection of L3 B. malayi is possible with electroporation and lipofection