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Prey Size Mediates Interference Competition and Predation Dynamics in a Large Carnivore Community
No full textDirect competition for resources is especially fierce among predators, leading to disproportionately strong effects on fitness and functional roles. These competitive effects are exacerbated in complex predator guilds with dominance hierarchies that have clear winners and losers. The direct costs of losing these competitions are well understood, but the drivers of such interactions, and their indirect effects on prey, are not. We evaluate the drivers of interference competition for cougars, and how such competition affects cougar-prey dynamics, by leveraging 23 years of cougar predation data from Yellowstone National Park, USA. We show that the effect of prey size is context-dependent, negatively affecting how often cougars kill ungulate prey but positively affecting how often wolves/bears find and steal cougar kills. Further, cougars increasingly kill smaller prey as larger, primary prey density decreases. Handling time is shorter for smaller prey, leading to less kleptoparasitism by wolves and bears when primary prey density is lower. Our study counters the theory suggesting that interference competition should increase at kills when prey density declines, interspecific competitor density increases, or kill rates increase. We demonstrate that predator, competitor, and prey traits drive the strength of and even dampen interference competition, possibly increasing coexistence in complex communities
Lipoprotein(a) Response to Dietary Saturated Fat Reduction: Relationship to Apolipoprotein(a) Size Polymorphism in African Americans
No full textBackground/Objectives: An elevated lipoprotein(a) [Lp(a)] level, which is a prevalent cardiovascular risk factor, is genetically determined by a size polymorphism of its apolipoprotein(a) [apo(a)] component. Despite its genetic control, Lp(a) level increases in response to dietary saturated fat (SFA) reduction. We tested the roles of apo(a) size and characteristics in modulating Lp(a) response to SFA reduction. Methods: We assessed apo(a) characteristics in 165 African Americans experiencing a 24% Lp(a) increase resulting from SFA reduction [16% at an average American Diet diet (AAD) to 6% at a DASH-type diet]. Apo(a) effects were tested based on the following factors: (1) the presence of a small atherogenic size (≤22 kringles), (2) phenotype (single or two isoforms), (3) isoform dominance, and (4) tertiles of combined kringle sizes. Results: There were no significant differences in Lp(a) increases between carriers vs. non-carriers of a small apo(a), between those with a single vs. two expressed isoforms, or in those with differing isoform dominance patterns (p \u3e 0.05 for all). The extent of Lp(a) increase differed across increasing tertiles of combined kringle sizes (p = 0.006 for trend). In a multivariate model, the AAD Lp(a) level was a significant predictor of Lp(a) changes (p \u3c 0.05). Relative increases in the allele-specific apo(a) level—an Lp(a) level associated with a defined apo(a) size—were similar across the apo(a) size spectrum. Conclusions: Reducing dietary SFA intake results in a 24% increase in Lp(a) level in African Americans across apo(a) sizes. Individuals with smaller apo(a) sizes reached an elevated Lp(a) level post-intervention compared to those with larger sizes, in some cases resulting in cardiovascular risk reclassification
Spatiotemporal Synchrony of Climate and Fire Occurrence Across North American Forests (1750–1880)
No full textAim: Increasing aridity has driven widespread synchronous fire occurrence in recent decades across North America. The lack of historical (pre-1880) fire records limits our ability to understand long-term continental fire-climate dynamics. The goal of this study is to use tree-ring reconstructions to determine the relationships between spatiotemporal patterns in historical climate and widespread fire occurrence in North American forests, and whether they are stable through time. This information will address a major knowledge gap required to inform projections of future fire. Location: North American Forests. Time Period: 1750–1880 CE. Major Taxa Studied: Trees. Methods: We applied regionalisation methods to tree-ring reconstructions of historical summer soil moisture and annual fire occurrence to independently identify broad- and fine-scale climate and fire regions based on common inter-annual variability
Academic Standards Subcommittee Minutes November 20, 2025
No full textWelcome and approval of October 16, 2025 minutes Topic 1: Continued discussion on the Academic Grievance Policy process Topic 2: Catalog year policy proposa
Effect of Space Radiation on the Mechanical Properties of High-Strength Polyethylene Nanocomposite Films
No full textThis study experimentally investigates the effects of prolonged radiation exposure on mechanical properties of high-strength, highly crystalline polyethylene (PE)/thermally reduced graphene oxide (TrGO) nanocomposite films for space applications. Prior to irradiation, PE/TrGO films were found to have tensile strengths up to ~4 GPa, more than 40 times that of conventional space-deployed membrane films (e.g., those used in solar sails) and over 59× the specific tensile strength. The PE/TrGO films were subjected to three radiation conditions to simulate space environmental conditions: 90Sr beta radiation (0.2 to 2.5 MeV), 80 keV electron beam irradiation, and 4.9 eV ultraviolet (254 nm) exposure. Under exposure to similar total ionizing doses (TID ~2.5 kGy, corresponding to ~3% of the unshielded annual electron dose in GEO) in a vacuum environment, the tensile strength showed little change after high-energy Sr-90 beta irradiation, but decreased by up to ~34.8% following intermediate-energy electron irradiation. Mechanical and Raman spectroscopic analyses were conducted to elucidate the radiation-induced structural and chemical changes before and after exposure, as well as to assess the protective effects of incorporated antioxidants on the stability of the PE films
Effectiveness of Silvicultural Options in Renewal of Trembling Aspen–Jack Pine Mixedwood Stands, 21 Years After Treatment
No full textRegenerating conifers after harvest through planting and postharvest broadcast application of herbicide is effective in ensuring the survival and growth of seedlings, but faces challenges in meeting broad social and ecological objectives of forest management. This study reports the effectiveness of alternative options in regenerating jack pine (Pinus banksiana Lamb.), 21 years after harvest of trembling aspen (Populus tremuloides Michx.)-dominated boreal mixedwood stands. The treatment options included (i) preharvest spray—aerial broadcast spray prior to harvest, (ii) postharvest partial spray—ground herbicide application in strips, (iii) partial harvest in strips, (iv) postharvest aerial broadcast, and (v) uncut reference. Twenty-one years after treatments, the four harvest treatments were similar in overstory density (4000 stems/ha) and basal area (BA, 20 m2/ha), but differed in composition and structure. The preharvest spray had an intimate mixture of aspen and jack pine (22% and 57% by BA, respectively), compared to spatial mosaics of aspen and pine corridors in the partial spray (36% and 41%), and aspen and maple corridors in the partial cut (21% and 31%). While the postharvest broadcast was pine-dominated (74% by BA) as expected, uncut and partial cut were similar in pine composition (10% by BA), which is inadequate for aspen and pine mixedwood stands. The early positive effects of preharvest spray and partial harvest on understory species abundance and diversity became neutral 21 years postharvest. The implications of these findings are discussed with respect to stand conditions before harvest, postharvest regeneration dynamics, and treatment objectives for the renewal of trembling aspen and jack pine mixedwood stands after harvest
Do the Theoretical Frameworks Surrounding Union Wage Negotiations Align With Empirical Data?
Get PDFThis paper investigates whether the strategic bargaining models developed in game theory align with outcomes observed in laboratory and field settings. We aim to synthesize theoretical literature with experimental and field data to assess the predictive power of game-theoretic models in labor-union wage negotiation contexts. We analyze Rubinstein\u27s bargaining model and its extensions, focusing on how relaxed assumptions affect equilibrium behavior, gains from trade, and dispute occurrence. The theoretical analysis reveals that many bargaining failures stem from asymmetric information between both parties, where delay, transaction costs, deadlines, and reputational effects lead to distinct equilibrium predictions. To test these theoretical predictions, we examine a broad array of ultimatum-style and structured bargaining experiments to identify alignment with the theoretical framework. Our experimental analysis shows that while simple ultimatum games often deviate from theoretical predictions due to fairness concerns, modified experiments with appropriate controls (such as discount factors, anonymity, and learning mechanisms) align closely with theory. Laboratory studies on disagreement payoffs and reputational concerns consistently support theoretical frameworks, though behavioral biases can still persist. Field data alignment proves more challenging. Most empirical union-firm studies focus on wage premiums rather than bargaining dynamics, making direct theoretical mapping difficult. However, structural estimation approaches and emerging real-time data analysis using natural language processing show promise
Roles of Organic Agriculture for Water Optimization in Arid and Semi-Arid Regions
Get PDFWater scarcity is a critical challenge in arid and semi-arid regions, where agricultural water consumption accounts for a significant portion of freshwater use. Conventional agriculture (CA) methods with high reliance on chemical and mechanical inputs often exacerbate this issue through soil degradation and water loss. This review aims to examine how different organic practices, such as mulching, cover cropping, composting, crop rotation, and no-till (NT) in combination with precision technologies, can contribute to water optimization, and it discusses the opportunities and challenges for the adoption and implementation of those practices. Previous findings show that organic agriculture (OA) may outperform CA in drought conditions. However, the problems of weed management in organic NT, trade-offs in cover crop biomass and moisture conservation, limited access to irrigation technologies, lack of awareness, and certification barriers challenge agricultural resilience and sustainability. Since the outcomes of OA practices depend on the crop type, local environment, and accessibility of knowledge and inputs, further context-specific research is needed to refine a scalable solution that maintains both productivity and resilience
The Climate Adaptation Intern Program: Training a Next-Generation Workforce While Bolstering Utah’s Capacity to Respond to Climate Change
Get PDFLaunched in Spring 2024, the Climate Adaptation Intern Program is a semester-long, cohort-style training program that pays undergraduates to work with experts and program leadership on developing fact sheets and other resources tailored to climate adaptation needs in Utah
USU Luminescence Lab Project 356: Durango Colorado Glacial and Fluvial Deposit Luminescence Age Results
No full textLuminescence dating of outwash terraces and glacial moraines. Project investigated the age of older (Bull Lake?) glacial advance sequences near Durango Colorado. Project was supervised by Dr. Jon Harvey at Fort Lewis College. Research was part of an undergraduate research project conducted by Josh Lingbloom