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Hillslope Position Influences Variations in Tree Growth Over Time
No full textTree growth depends on interactions between adjacent vegetation, local climate, and landscape properties. In arid, semi-arid, and Mediterranean climatic regions, hillslope position has been recognized as an important mediator of annual tree growth and its resilience to hydroclimatic variation, such as periods of drought. This relationship has garnered less research in humid, temperate regions such as Rhode Island, despite the fact that post-glacial landscapes can exhibit large variability in subsurface properties over small spatial scales. To begin addressing this gap, we cored 42 oak trees along a hillslope in Tiverton, Rhode Island, during the summer of 2024. We used image analysis software to measure annual growth for each tree. Our preliminary analyses identified greater maximum and median annual ring widths for trees lower on the hillslope compared to their similarly aged, but smaller diameter, counterparts higher on the hillslope. We also found that the minimum annual ring width was approximately the same regardless of hillslope position, and despite systematic differences in tree size. Broadly, all trees exhibited reductions in annual ring width at older ages, but the magnitude of these signals varied among hillslope positions, with trees at lower positions displaying the largest age-related changes in growth. The greater median and maximum ring widths of lower trees may indicate that conditions were more favorable for rapid growth at the bottom of the hillslope, especially in the early stages of their lives. In trees located on the upper part of the hillslope, the smaller absolute range of ring widths could suggest that these trees grew more consistently, regardless of climatic conditions. Overall, these results reveal that hillslope position is an important control on interannual growth patterns of oaks in this area. This provides a basis from which we will extract and analyze other growth signals that are indicative of sensitivity to hydroclimatic variability over the past century. Ultimately this work will provide further insight into the relative importance of stand age, topography, and climate as controls on the resilience of local forests
Maternal mercury transfer from pregnant spiny (Squalus acanthias) and smooth (Mustelus canis) dogfish to their pups through differing reproductive strategies
Get PDFMercury (Hg) is a bioaccumulative contaminant that can be transferred from pregnant females to developing embryos (i.e., intrauterine maternal Hg transfer); thus, leading to health deficits in offspring. This study examined Hg transfer in the ovoviviparous spiny dogfish (Squalus acanthias) and viviparous smooth dogfish (Mustelus canis). Female dogfish were collected from Narragansett Bay, Rhode Island Sound, and Block Island Sound via rod & reel, gillnet, and trawling. In the laboratory, intrauterine pups were excised from pregnant dogfish, after which samples of mother and pup muscle tissue were analyzed for total Hg concentrations ([Hg] in ppm dry weight) using automated atomic-absorption spectroscopy. Maternal muscle [Hg] was positively related to TL within both species, indicating bioaccumulation of the contaminant in mature females. Muscle [Hg] as a function of age followed similar trends between both species, however, Hg bioaccumulation was much higher in males than females for both species indicating the offloading of Hg to pups in females. Smooth dogfish pups exhibited higher muscle [Hg] than spiny dogfish pups, indicating a viviparous reproductive strategy results in higher amounts of Hg offloading than ovoviviparity. There existed a significant positive relationship between maternal and pup muscle [Hg] within smooth dogfish however no such relationship was exhibited in spiny dogfish. These results suggest that maternal Hg transfer occurs in both spiny and smooth dogfish, and the viviparous reproductive strategy of smooth dogfish results in higher amounts of Hg offloading to pups than the ovoviviparous strategy of spiny dogfish
Treatment of wet marine diesel exhaust with catalytic material based on perovskite photovoltaic incorporating mixed-valent vanadium oxide (V3O7)
No full textDiesel exhaust gases such as NOx and SOx are significant contributors to pollution in today’s atmosphere. The International Convention for the Prevention of Pollution from Ships (MARPOL) Annex VI has a tiered system for regulating these gases from marine diesel engines. The current standard, Tier III, limits the NOx emissions based on a vessel’s horsepower. Our approach is based on perovskite photovoltaic architecture using fluorine-doped tin oxide (FTO) glass substrates coated with four layers applied by doctor blading. The first two being a TiO2 layer and a mesoporous TiO2 layer, then aperovskite layer and V3O7 layer respectively. The perovskite layer solution was formed from 0.3481g FAI, 1.0125g PbI2, 0.1465g PbBr2, and 0.0449g methylammonium bromide (MABr) in 2mL (4DMF:1DMSO) and 105.2 μL cesium iodide (CsI) solution (9.7430 g CsI in 25mL DMSO) to activate in a conical vial. The mixed-valent vanadium oxide layer was formed by hydrothermal synthesis of 0.2275g vanadium oxide (V2O5) and 0.005g 4-aminophenol (H2NC6H4OH) at 180°C for 48 hours. This poster highlights the substrates and materials formed and tested via XRD, XRF, and artificial exhaust seawater NO3- and NO2- Hach spectrometry
An Electrochemical Biosensor to Screen Oysters for Perkinsus marinus
No full textMollusk disease-causing protists affect the ecology and economy of Narragansett Bay marine communities and their habitats. Perkinsus marinus is the causative agent of Dermo disease in oysters. The detection of this pathogenic protist informs aquaculturists about the distribution and abundance of Dermo disease but current methods are time-consuming and costly. Electrochemical biosensing is an emerging, cost-effective technique that could provide real-time detection in the field. A P. marinus DNA-coated electrode and a redox indicator were used with a custom-built potentiostat to measure the current response under applied potential for various targets. The constructed biosensor was able to specifically distinguish complementary and non-complementary oligonucleotides at pM detection levels. Future tests will include the identification of P. marinus in treated and non-treated oysters which will confirm the potential of the device as a practical screening tool for real-time detection
From Andy Warhol to Barbie: Copyright’s Fair Use Doctrine After Andy Warhol Foundation v. Goldsmith
Get PDFEvaluating Fourth-Grader’s Perception of Engineering Through a Community-Engaged Project (Evaluation)
Get PDFTo meet the complex challenges of the future, there needs to be an increase in the number of students pursuing , STEM and engineering. To grow those numbers, students must have an understanding and interest in engineering in order to pursue it as a career option. However, literature has shown that children hold misconceptions about the engineering profession, which can deter potential future engineers from the field. This underscores the importance of introducing engineering concepts at a young age. Over the past ten years, the Next Generation Science Standards (NGSS) have been integrated into state school curricula, increasing the emphasis on engineering in K-12. Although the NGSS helps introduce engineering at a young age, it can be difficult for teachers to incorporate engineering into their lessons without the required background knowledge. To help mitigate this challenge, a community engagement project was created, bridging a university with a local school district to help fourth-grade teachers incorporate engineering lessons into their classrooms. Engineering and education majors co-taught lessons to fourth-grade students about engineering, wind energy, and the engineering design process. The fourth-grade students applied the engineering design process to build model wind turbines showcased at a celebration event. This study seeks to understand fourth-grade students’ perceptions of an engineer before and after participating in this project. Students completed a pre- and post-intervention assessment where they needed to answer the question, “What is an engineer?” Utilizing a constructivist approach, we examined students\u27 knowledge development based on their lived experiences. Our analysis compares pre- and post-intervention responses, considering their experiences within the context of the community-engaged project. We found that students described engineering differently between the pre- and post-intervention responses, and they described engineers with more words related to the engineering design process. This helps us understand the impacts of the community-engaged project on students’ perceptions of engineering, which can help inform future educational initiatives that may enhance engineering literacy among K-12 students
Samson House: East Elevation
No full textArchitect blueprint of the east elevation of the Samson House.https://docs.rwu.edu/baker_plans/1184/thumbnail.jp
Samson House 028: Dismantling the Brownell House
No full textDismantling the Brownell House in Portsmouth, RI to be re-erected in Little Compton, RI.https://docs.rwu.edu/baker_images/1934/thumbnail.jp
Samson House 042: Chimney Dig at Brownell House
No full textChimney Dig at Brownell Househttps://docs.rwu.edu/baker_images/1941/thumbnail.jp