Feeding Competition and Play: Exploring the Role of Play in Managing Social Tension in Captive Hamadryas Baboons (Papio hamadryas)

Chimpanzees and bonobos show increased social play prior to competitive feeding periods, suggesting that play may have an important role in mitigating conflict during periods of high social tension. In the present study, we investigated whether captive hamadryas baboons showed increased play behavior or showed selectivity in play partner choice in periods of high social tension. A high-value scattered feeding was provided at a fixed time each day, creating social tension leading up to the competitive feeding period. Using scan and focal observations, we recorded play, co-feeding, aggression, submission, affiliation, and partnerships during four distinct periods: control, early pre-feeding, late pre-feeding, and feeding. Contrary to predictions, the frequency of play behavior did not differ significantly across the observation periods. Play partner choice had no influence on co-feeding partner selection. However, during the control period, partner choice was influenced by kinship, age difference, and sex, while during the pre-feeding and the feeding period, partner choice was primarily influenced by kinship. These findings suggest that while play may not function as a general tension-reduction mechanism in hamadryas baboons, kinship remains a crucial factor in social interactions during periods of heightened tension

Same Dynamics, Different Graph: Exploring Correlations, Similarities, and Renormalization of Dynamics on Networks Using Temporal Distance Theory

Analyzing dynamics that take place on graphs (networks) is fundamental to modern network theory, with applications spanning biology, social networks, and engineering systems. A significant body of research exists that considers the similarity and scaling of network topologies. However, understanding how dynamic behavior varies across different graph topologies - particularly how signals propagate and dynamic behaviors scale between small and large networks - remains a significant challenge. To address this challenge, this thesis presents a comprehensive framework to analyze how dynamic signals propagate and scale on network topologies using temporal distance theory. Three research goals were accomplished. First, a statistical analysis of dynamic signal propagation patterns on the complete set of non-isomorphic graphs with 9 or less vertices (nodes) was performed. Using temporal distance theory to generate the data eliminated the need for over a hundred million simulations across 273,191 network topologies and three distinct dynamic models. Second, a novel algorithm was developed to quantitatively measure the similarity between dynamics taking place on different networks called TD-Match. TD-Match is robust to graph isomorphs and can be used as a look-up function for dynamically similar networks in complete sets of network topologies. By comparing the similarity of the dynamics on graphs, this methodology can reveal graph sets that contain same dynamics, different graphs. Finally, this work developed a novel methodology for dimensionally scaling, or renormalizing, a network that focuses on the characteristics of the dynamics propagating on that network, independent of topology. As far as the author is aware, this is the first renormalization method that prioritizes dynamic signals on the network instead of network topology. A new tool called TD-MORPH was developed to explore TD-Match and dynamic renormalization. The statistical analyses, TD-Match algorithm, and dynamic renormalization method offer a new framework for network analysis. This work provides a computationally efficient foundation for future studies seeking insight into the interplay between graph structures and network dynamics

Synthesis of Dimeric Pyridinium Phenolate Dyes and Investigation of their Photophysical Properties

Solvatochromic dyes have advanced the field of organic materials chemistry with their intriguing photophysical properties. They have applications as solvent polarity sensors as well as probes for studying solvent effects in supramolecular chemistry, chemical sensing, and examining biological processes. This study focuses on synthesising a range of bridged pyridinium based chromophores and investigating their photophysical behavior. This work aims to explore how solvatochromism and exciton coupling enhances the optical and electronic properties of these dyes. To do this, dimer 4,4\u27-((1,3-phenylenebis(methylene))bis(pyridine-1-ium-1,4-diyl))diphenolate (19), 4,4\u27-((1,2-phenylenebis(methylene))bis(pyridine-1-ium-1,4-diyl))diphenolate (21) and reference compound, 4-(1-benzylpyridin-1-ium-4-yl)phenolate (23) were synthesised in good yields using simple SN2 reaction. UV-vis spectroscopic analysis of these dyes was performed and compared against each other. The absorption spectrum profiles revealed that dimer 19 and 21 exhibited an enhanced negative solvatochromism compared to monomer 23. It was also observed that bichromophoric 19 and 21 exhibited intense absorption with two peaks as a result of exciton coupling. The two chromophores interact intramolecularly, resulting in the splitting and an intense absorption band. This new findings will expand the applications of these dimeric phenolate dyes in the field of material organic chemistry

Single Amino Acid Changes Impact the Ability of Drosophila melanogaster Cecropins to Inhibit Growth of Providencia Pathogens

As antibiotic-resistant bacteria spread worldwide, the need to develop novel antimicrobial agents is urgent. One rich source of potential antimicrobials is the insect immune system, as insects produce a wide range of antimicrobial peptides (AMPs) with diverse sequences and structures. Insects also encounter many bacterial pathogens, some of which are closely related to pathogens of clinical relevance. However, despite interest in AMPs as therapeutics, the relationships between the amino acid sequence, biophysical properties, antimicrobial activity, and specificity are still not generalizable. To improve our understanding of these relationships, we assessed how single amino acid changes in cecropin AMPs produced by the fruit fly, Drosophila melanogaster, impact both their structure and their ability to inhibit the growth of Providencia species isolated from wild-caught D. melanogaster. These pathogens are of particular interest as they have a range of virulence in fruit flies, and work in vivo suggests that differences in virulence could be partially attributable to differential susceptibility to AMPs. D. melanogaster cecropins are 40 amino acids long but vary at only 5 residues with largely conservative changes. We found that these changes could impact inhibitory concentrations by up to 8-fold against Providencia species. Our investigation focused on a single amino acid position due to the importance of a flexible “hinge” in cecropin function. We found that altering the identity of this amino acid alone greatly impacted antimicrobial activity, changing bacterial susceptibility up to 16-fold. Generally, Providencia species that are less virulent in vivo are more susceptible to cecropin AMPs in vitro. We also observed differences in the kinetics of permeabilization and bacterial killing between species, suggesting that peptide-membrane interactions were differently affected by single amino acid changes and that bacteria in this genus may vary in their membrane composition

Flexible Manufacturing to Fabricate Patient-Specific Implants

https://digitalcommons.bucknell.edu/fac_coll/1064/thumbnail.jp

Assessing Genetic Diversity and Population Structure in the Imperiled Aconitum reclinatum (white monkshood), an Endemic Wildflower of Central Appalachia

Aconitum reclinatum, white monkshood (Ranunculaceae), is a Pennsylvania critically imperiled plant species found in five states of the Appalachian region of the United States: Pennsylvania, West Virginia, Virginia, North Carolina, and Tennessee. This plant is adapted to cool, moist environments but faces threats from increasing habitat loss, deer browse, logging, and changes in rainfall and temperature associated with climate change. Comprehensive knowledge of A. reclinatum genetic population structure remains limited. To address this, we collaborated with Natural Heritage programs within the range of A. reclinatum to sample populations across the species distribution and generate a genotyping-by-sequencing data set of single-nucleotide polymorphisms (SNPs). This dataset was used to calculate population statistics (heterozygosity, inbreeding coefficient, fixation index) and infer population health and structure by conducting a Principal Component Analysis (PCA), spare non-negative matrix factorization (sNMF) analysis, and testing for a correlation between geographic and genetic distance. Our findings suggest strong genetic structure among populations of A. reclinatum and genetic isolation between populations. Natural Heritage programs should continue efforts to maintain populations and initiate further efforts for some populations that are experiencing lower genetic health. Additionally, genetic rescue may be required for some populations, although compatibility should be tested before it is implemented

Computationally Modeling Standard Space Frames and Origami Inspired Frames: A Comparative Analysis

Space structures, including space frames or space trusses depending on the type of connections, are a three-dimensional structure made of interconnected members that are often used for roof supporting systems. These structures can distribute loads in three dimensions and support wide spans without the need for many intermediate supports. Deployable structures are systems that can be folded for easy disassembly and transportation, and then can be simply “deployed” for their desired purpose. A space structure inspired by the geometry of the Miura-Ori origami fold, referred to as the origami frame or truss, was computationally modeled. This was done to create a space structure system that has inherent folding ability, allowing for a wide range of future applications as a deployable structure. This study aimed to compare a standard space truss with the origami truss by evaluating the structural performance of both trusses in terms of geometrical properties, load capacity, and deflection. The goal of this study was to conclude if the origami truss was feasible as compared to the standard space truss, in order to allow for future studies into its fabrication, specifically noting its advantage of deployability. The origami truss was found to have both advantages and disadvantages as compared to the space truss. Advantages include requiring fewer members to cover a given span, correlating to the self-weight of the structure, and a decrease in complexity of the connections. Additionally, it was found that the total load capacities of the structures are essentially equal. Disadvantages of the origami truss include a greater deflection and number of required connections for a given span. Despite the drawbacks, the origami truss is concluded to be a viable structure that needs further investigations to understand the limitations that would need to be placed on it for use in practice

Theoretical Study of Phase-Ordering Kinetics with an Anisotropic Surface Tension

Coarsening describes the phase-separation dynamics that follows after a temperature quench from a stable to unstable region of the phase diagram in binary systems. Whereas binary systems with an isotropic surface tension have been thoroughly examined and modeled, the case of an anisotropic surface tension lacks the same degree of analysis and development. In this thesis, we demonstrate the self-consistency of the scaling hypothesis with an anisotropic surface tension in the dilute limit. We begin by assuming weak anisotropy in the surface tension and working only to first order in perturbation theory. Following a similar approach laid out in the isotropic theory, we derive an equation of motion in terms of a scaled parameter x ≡ R0/L(t) , where R0 is the isotropic radius of the droplet and L(t) is the characteristic length scale of the system, and t is time. We then solve this equation of motion to observe how the anisotropy in the surface tension influences the drop shape and drop size distribution. We find that the drop size distribution, though different from the isotropic case, may be consistently expressed in terms of the scaled parameter x, thus achieving a self-consistent theory of scaling in the anisotropic case. Furthermore, we find that the characteristic length scale of the system remains the same as the isotropic theory L ∼ t^{1/3}, but we also find that the domain structures are governed by the scaled parameter x rather than assuming their equilibrium shapes (Wulff shapes), in direct opposition to previous expectations

Chromosome segregation dynamics during Meiosis I, Meiosis II, and Mitosis cell divisions in Acheta domesticus (House crickets)

Chromosomes exhibit diverse types of organization and movement during the cell division process. Meiosis is essential for sexual reproduction, producing haploid cells from diploid precursors. In meiosis I, homologous chromosomes pair up, and separate in anaphase I, with two chromatids moving toward each pole. In meiosis II, the sister chromatids move to opposite poles during anaphase II and produce haploid cells. In contrast, in mitosis, the chromosomes are copied and distributed to produce genetically identical diploid somatic cells. Understanding the behavior of chromosomes during mitosis and meiosis is significant for accurate chromosome segregation to prevent birth defects and diseases like cancer. Currently, there is a notable gap in the literature—the absence of comparative assessments of chromosome dynamics across mitosis, meiosis I, and meiosis II within a single species. In this project, we used live-cell imaging of house cricket (Acheta domesticus) spermatocytes to characterize chromosome movement in mitosis, meiosis I, and meiosis II, providing insights into their unique dynamics. Through this analysis, we have determined how chromosome position changes from metaphase to anaphase in all three division types. We have also determined that chromosomes move to the spindle poles at the same rates in anaphase I and anaphase II but move at double the meiotic rate of movement in mitotic anaphase

The Lives of Bats: A Natural History

Bats are the second-largest order of mammals and inhabit almost every corner of the globe, but these secretive creatures are often maligned and misunderstood. With more than 1,400 species worldwide, they are crucial contributors to ecosystems, controlling insect populations and fulfilling an essential role as pollinators. This one-of-a-kind guide showcases the unique characteristics and extraordinary diversity of our planet’s bat life, providing an inviting introduction to these marvelous creatures. Written by a leading expert and packed with the latest scientific findings, The Lives of Bats blends diagrams and stunning photographs with in-depth coverage of profiled species to offer an incomparable look at these unsung heroes of the natural world. Includes a wealth of stunning color photos Features dozens of representative species profiles that demonstrate the remarkable diversity and adaptability of the only mammals on Earth capable of powered flight Covers key topics such as anatomy, echolocation, diet, thermoregulation, mating, diseases, and immunity Discusses human relationships with bats Essential reading for wildlife lovers everywherehttps://digitalcommons.bucknell.edu/books/1313/thumbnail.jp