University of Southern Mississippi
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Filling Conservation Gaps For Gulf Sturgeon (Acipenser desotoi) Using Specialized Acoustic Transmitters
No full textGulf Sturgeon (GS; Acipenser desotoi) are a federally threatened, anadromous fish found in seven river systems along the northern Gulf of Mexico. While not managed as distinct population segments, GS are divided into western (WPU) and eastern (EPU) populations based on the location of their natal river in relation to the Mobile Bay. Acoustic telemetry has been a common method of monitoring GS; however, due to data from this methodology being presence-absence, inferences must be made on why GS are where they are and what they are experiencing there. Recent innovations in acoustic transmitters, such as InnovaSeaTM V16AT temperature and accelerometer transmitters (AT-Tags), have allowed for an increased ability to understand GS movement and behavior. Through supplementing water monitoring equipment with AT-Tags, study is the first to describe the thermal regimes GS experience within the WPU systems and found that conditions within the Pearl and Pascagoula rivers’ spawning and summer holding reaches are warmer comparatively to far eastern river counterparts. Additionally, this study attempted to relate activity of GS from AT-Tags to presumed behaviors in overwintering habitat. Although specific behaviors could not be parsed out, observed zonal residency events were consistent with trends in recent studies, showing potential for accelerometer transmitters in future studies. This thesis demonstrates how advancements in acoustic telemetry can support inferences on GS behavior by providing more fine-scale data and can provide a foundation for future research aimed at more targeted conservation management of GS
Describing and Characterizing Potential Lemon Shark (Negaprion brevirostris) Nursery Habitat in Mississippi Coastal Waters
No full textThe Lemon Shark (Negaprion brevirostris) is a member of the large coastal shark complex found throughout North and South American coastal waters in the Atlantic Ocean, Gulf of Mexico (GoM), and Pacific. The species is currently known to use Louisiana waters as their northernmost nursery habitat within the GoM, but recent juvenile captures in Mississippi (MS) waters prompted further exploration of the species. Data from long-term gillnet monitoring in conjunction with a focused gillnet study predominantly around Cat Island, MS was used to identify depth as the main factor influencing capture. Lemon Sharks were acoustically tagged to monitor movements throughout the system and individuals were observed around Cat Island as well as other MS barrier islands. This study used different spatial and community metrics to evaluate association of Lemon Sharks with different habitats and regions across the study area. Kernel utilization distribution demonstrated a reduced use area during colder temperatures with movements restricted to the southern region of Cat Island. Through network analyses and community detection algorithms (CDA), younger individuals were observed utilizing a more restricted region than older individuals and were more frequently associated with their location of capture. An evaluation of habitat demonstrated a preference for sandy-bottom, open habitats as well as seagrass. This study is the first to understand the extent of Lemon Shark use of MS coastal waters as potential nursery habitat and to identify key habitat characteristics associated with the species within this area where they previously have rarely been found
Polarized Without the Other Side: Measurements from Congress on Bluesky
No full textPolitical polarization seems to be rising at an alarming rate in the United States. Those on opposite sides of the political spectrum are increasingly viewing each other more negatively, with this effect amplified in the rhetoric of elected officials. In this research, I examine social media posts from Democratic representatives on Bluesky, a growing social media platform with a mostly liberal user base. I collect a novel dataset directly from Bluesky and construct several independent variables. These include 4 distinct measures of polarization (positivity, affective polarization, issue polarization, and cross-party mentions), an indicator for house membership, and 4 indicators for salient policy-related content (science, economic, healthcare, and governance). I model the predicted effect of each variable on like-count and reply-count while controlling for the number of account followers. Results indicate that 3 of the 4 polarization variables significantly predict an increase in engagement. House membership significantly predicts less engagement. Finally, I find mixed results for the policy-related variables, leading to a discussion about future research on user engagement. These results show that the engaging effect of polarizing speech, found in previous literature, is robust even on a partisan platform without users from the other side of the aisle
Morphology to Thermal-Mechanical Property Relationships of Dispersed Carbon Nanoparticle Epoxy Composites
No full textNanoparticle-reinforced polymer composites have attracted growing interest for both kinetic and non-kinetic applications due to their ability to improve mechanical performance at low filler contents. Among these, graphene nanoplatelets (GNPs) have been widely studied for their high aspect ratio, stiffness, and energy dissipation potential. However, cost and processing challenges have led to interest in graphite as a potential alternative, given its similar chemical structure and lower cost. This study investigates the use of graphite flakes compared to GNPs and characterizes the impact on mechanical performance and strain rate dependent behavior under various compressive loadings.
Graphene and graphite were incorporated at 0.1 wt% and 0.3 wt% loadings via direct addition into a diglycidyl ether of bisphenol F (DGEBF) epoxy matrix, and fiber-reinforced composites were fabricated using basalt or E-glass through Vacuum Assisted Resin Transfer Molding (VARTM). Mechanical characterization included quasi-static tension and flexure, high-rate compression via Split Hopkinson Pressure Bar (SHPB), and viscoelastic property evaluation using dynamic mechanical analysis (DMA). Thermal performance was assessed through thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC).
Results showed that 0.1 wt% GNP provided the highest stiffness increase without compromising strain capacity, while graphite loadings led to significant performance losses under high-rate compression. Thermal analysis revealed no significant shifts in glass transition temperature or degradation onset. While graphite offers potential reinforcement in low-rate regimes, graphene was more effective under high rate conditions, suggesting it remains the more suitable additive for high-performance applications where both stiffness and toughness are required
Macroinvertebrate Community Dynamics in a Recovering, Hypersaline Estuary
No full textThe Bahia Grande is a 6,500—acre tidal basin located at the southernmost tip of Texas. Tidal flow into this coastal estuary was cut off in the 1930s, causing the basin to dry up for ~70 y. A pilot channel connecting the Bahia Grande to tidal waters was constructed in 2005, allowing flooding of the basin to occur. Throughout the period reported herein (2005–2019), the system remained characterized by persistent spatial and temporal episodes of extreme hypersalinity (\u3e70)—a critical factor influencing estuarine community composition and driving key ecological processes. With additional rehabilitation actions forthcoming, characterization of the estuary is essential to evaluate the effectiveness of future restoration efforts. In this study, we analyzed macroinvertebrate data collected from 2005–2019 to evaluate community turnover as well as spatial variation driven by salinity gradients (ranging from 36 to 178). We found 5 distinct ecological groups throughout the study period: 1) early colonizers, 2) high salinity, 3) early stabilization, 4) middle stabilization, and 5) late stabilization. In addition, we found that less saline areas of the basin support different macroinvertebrate assemblages than more saline areas, suggesting that full ecological recovery of the Bahia Grande has yet to be achieved. These findings provide unique insight into the ecological progression of a reflooded, hypersaline estuary (sequence of community turnover, persistence of salinity—driven assemblages, limited recovery of sensitive taxa) while also offering an assessment of the estuary’s current rehabilitation status and critical baseline data to inform and evaluate the outcomes of future restoration efforts
Reducing Transactional Distance in A Hybrid-Flexible Learning Environment in Higher Education: Interaction and Engagement Despite Asynchronous Communication
Get PDFThis study explores the implementation of an asynchronous video-based guest lecture in an undergraduate teacher education program in Switzerland. It describes how the guest lecture was delivered to foster an interactive and engaging environment for learners and to mimic two-way communication. The study applies the tenets of the Theory of Transactional Distance in examining the student-teacher interaction in a hybrid-flexible learning environment to promote quality dialogue, participation, critical reflection, and to foster a caring relationship. It describes the instructional process and the use of video splicing to mimic interaction between the students, who were physically present on campus, and the guest lecturer ‘joining’ them asynchronously from a university overseas. A survey and a written reflection captured students’ perceptions of how close or distant they felt to the guest lecturer and how this sense of closeness or distance impacted their engagement and learning. A debriefing grounded in the pedagogy of care captured the guest lecturer’s experience. All students (n = 10) expressed appreciation for the opportunity to be part of a video-based interactive lecture. They were grateful that the guest lecturer had taken the time to interact with them, listen to their questions, and to respond to their specific questions. All respondents enjoyed the innovative approach approximating interaction in an asynchronous setting. Ways to minimize transactional distance between the geographically distant guest lecturer and the students are discussed along with strategies to increase responsiveness to students’ individual questions and to demonstrate care for their learning. This article may be of interest to educators who strive to increase engagement and interaction in online or hybrid learning environments and are looking for ways to decrease the distance between themselves and their students. The study contributes to a better understanding of the use of video-based teaching approaches in hybrid education
Common Snook in Mississippi
No full texta Common Snook captured in Mississippi waters. For more information on the range expansion of this species, see Weidner et al. 2025, Gulf and Caribbean Research volume 36, pages SC1-SC4.https://aquila.usm.edu/gcrgallery/1006/thumbnail.jp
