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Development of a MATLAB-COMSOL Integrated GUI for Designing Multimode THz Fibers
No full textThe THz region, which spans from 0.1 to 10 THz, holds significant potential for applications intelecommunications, medical imaging, and spectroscopy due to its unique properties, such as low photon energy and high penetration depth. The overall goal of this research project is to design optical fibers for use in the terahertz region, run them through electromagnetic Multiphysics COMSOL simulations, and to fabricate the fibers using a 3D resin printer. COMSOL is powerful in computing intricate Multiphysics equations, however it is difficult and tedious to manually set up a simulation within the software. Thus, this project focuses on creating a graphical user interface (GUI) to integrate MATLAB and COMSOL, using COMSOL’s live link server. This GUI allows the user to input a series of parameters for the geometry and material of the fiber, and the instructions for a simulation, then the GUI can then output data from the simulation; both numerically and graphically. With the developed GUI, a unique multimode THz negative curvature fiber design based on UV-cured photosensitive resin is proposed and analyzed in detail to reach over 100 modes below the figure of merit loss of 1 dB/m for potential 6G communication protocols
Bacteriophage-host interactions are influenced by genetic variation in genomic islands
No full textT7-like bacteriophages that infect coastal cyanobacteria are ubiquitous in marine environments, where they impact the composition, evolution, and mortality of their hosts. Often these phages are very host-specific using tail-fibers, known as receptor binding proteins, to recognize and attach to lipopolysaccharide (LPS) features on the host\u27s surface. Previous studies have described the T7-like phage genome as having three genomic islands where an abundance of horizontal gene transfer occurs. In particular, tail-fibers genes are observed to have the highest rate of transfer. We have isolated and sequenced 24 Synechococcus-infecting T7-like phages from Narragansett Bay, Rhode Island to identify genes that may be important in phage-host interactions. In this study we aimed to characterize a gene in the second genomic island that was extremely divergent among the sequenced isolates with only 14% to 47% predicted amino acid sequence identity. To explore possible functions of the gene, we utilized AlphaFold2 to make 3D models of single polypeptides and their corresponding homotrimers. Despite the amino acid variation, the predicted protein structures were all very similar, with the predicted shape suggesting that these proteins might serve as receptor binding proteins. Host range analysis was performed by setting up pairwise cross-infection assays using 6 Synechococcus cell types. A distinct infection pattern was seen; all the phages could infect a Synechococcus in clade I (MV1320), but only some could infect a Synechococcus in clade VI (WH8018). An infection kinetics experiment was then conducted to assess how the different gene variants may influence phage infection dynamics, such as attachment to cells and replication in host cells. For this assay, four T7-like phages were added to host cells (MV1320) and multiple samples were collected over a 48-hour period. At each time point the cells were removed via filtration and the extracellular DNA was quantified using a qPCR assay. We found the four phages showed different levels of both attachment to the cells and replication within the host cells. Further analysis of the function and content of genes located in the other islands will aid in the understanding of how the exchange of genetic material between phages impacts interactions with host cells
Implementing the International Law on Ship Recycling: Is Inddia on Target or off Target?
No full textSensorized Autonomous Manipulation Platform for Underwater
Get PDFResearchers from Brown University, University of Massachusetts Lowell (UML), and the Office of Naval Research (ONR) are developing autonomous underwater robots for naval applications. The robots must be able to autonomously complete the tasks it encounters. Roger Williams University developed a submersible instrumented back plane and four interchangeable task modules. The sensorized task platform quantitatively measures task performance for researcher evaluation
Four-Dimensional Ecology Education (4DEE) for Everyone: Teaching Ecology to Non-majors
Get PDFOriginally developed for application to ecology courses for undergraduate majors, the Four-Dimensional Ecology Education (4DEE) Framework offers possibilities for adaptation to courses with ecology content for many other audiences. Recognizing the extraordinary range of classroom contexts and constraints, we developed some general, flexible recommendations and approaches to guide instructors in adapting the 4DEE Framework for an array of non-major audiences and classroom context needs. Our hope is that 4DEE-aligned courses for non-majors will provide these students with greater appreciation of ecology and inspire them to use their knowledge to address many critical environmental issues in their personal and professional lives. Many of our recommendations likely apply to natural science, engineering, and math majors as well. We encourage more ecologists to embrace teaching non-majors courses as a response to the urgent need to improve ecological literacy for everyone
A second look at active shooter events: Expanding our understanding of key factors
Get PDFIn the current study, we investigate active shooter events (ASEs) with emphasis on expanding our understanding of key factors involved in these events. The impetus for this study is a 2015 exploration (Gamache et al., 2015) that highlighted common perpetrator and event characteristics in ASEs occurring in the US prior to 2014. Since the 2015 study, mass-shooting events have moved from tragic, isolated incidents, to a phenomenon that is widely discussed in the media and highly politicized. Our goal was to investigate continued trends, if any exist, and to compare our current sample of ASEs to the sample utilized in 2015. Differences were observed on two factors: events occurring after 2015 were significantly less likely to occur at a school compared to the early sample; and the presence of other stressors were present in the early sample but not in the recent sample. Recent data continues to show that active shooter events are deadly events resulting in significant loss of life and shared trauma. With the increasing frequency,these events are becoming a public health concern with major political and societal ramifications, and continued research must investigate this evolving form of public violence
Differences in aquatic respiration in two contrasting streams: forested vs. agricultural
No full textLand cover changes alter hydrologic (e.g., infiltration-runoff), biochemical (e.g., nutrient loads), and ecological processes (e.g., stream metabolism). We quantified differences in aquatic ecosystem respiration in two contrasting stream reaches from a forested watershed in Colorado (1st-order reach) and an agricultural watershed in Iowa (3rd-order reach). We conducted two rounds of experiments in each of these reaches, featuring four sets of continuous injections of Cl− as a conservative tracer, resazurin as a proxy for aerobic respiration, and one of the following nutrient treatments: (a) N, (b) N + C, (c) N + P, and (d) C + N + P. With those methods providing consistent information about solute transport, stream respiration, and nutrient processing at the same spatiotemporal scales, we sought to address: (1) Are respiration rates correlated with conservative transport metrics in forested or agricultural streams? and (2) Can short-term modifications of stoichiometric conditions (C:N:P ratios) override respiration patterns, or do long-term physicochemical conditions control those patterns? We found greater respiration in the reach located in the forested watershed but no correlations between respiration, discharge, and advective or transient storage timescales. All the experiments conducted in the agricultural stream featured a reaction-limited transformation of resazurin, suggesting the existence of nutrient or carbon limitations on respiration that our short-term nutrient treatments did not remove. In contrast, the forested stream was characterized by nearly balanced transformation and transient storage timescales. We also found that our short-lived nutrient treatments had minimal influence on the significantly different respiration patterns observed between reaches, which are most likely driven by the longer-term and highly contrasting ambient nutrient concentrations at each site. Our experimental results agree with large-scale analyses suggesting greater microbial respiration in headwater streams in the U.S. Western Mountains region than in second-to-third-order streams in the U.S. Temperate Plains region
Samson House: Drawing of Rebuilt House
No full textDrawing of the plan for the rebuild house showing the Portsmouth and Tiverton Sides.https://docs.rwu.edu/baker_plans/1181/thumbnail.jp