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Full-Text Articles in Life Sciences

Computationally Modeling Dynamic Biological Systems, Katherine Jarvis Dec 2021

Computationally Modeling Dynamic Biological Systems, Katherine Jarvis

Electronic Theses and Dissertations

Modeling biological systems furthers our understanding of dynamic relationships and helps us make predictions of the unknown properties of the system. The simple interplay between individual species in a dynamic environment over time can be modeled by equation-based modeling or agent- based modeling (ABM). Equation based modeling describes the change in species quantity using ordinary differential equations (ODE) and is dependent on the quantity of other species in the system as well as a predetermined rates of change. Unfortunately, this method of modeling does not model each individual agent in each species over time so individual dynamics are assumed to …


Biotic Interactions At Species’ Range Limits In A Changing Climate, Isaac Shepard Dec 2021

Biotic Interactions At Species’ Range Limits In A Changing Climate, Isaac Shepard

Electronic Theses and Dissertations

As the global climate changes, many species are shifting their geographic ranges, often towards the poles or upslope in elevation. The ubiquity of these observation has renewed discussions about the mechanisms that determine species’ range margins. Leading hypotheses state abiotic variables should be the most important factor for setting range limits in environmentally stressful habitats. However, I propose an alternative hypothesis that biotic interactions may still be critically important for setting range limits, even in abiotically stressful habitats. Using a model system of ponds in the Rocky Mountains of Colorado, I developed several field experiments to empirically test the role …


Forest Disturbance And Occupancy Patterns Of Carnivores: Results Of A Large-Scale Field Study In Maine, Usa, Bryn E. Evans Dec 2021

Forest Disturbance And Occupancy Patterns Of Carnivores: Results Of A Large-Scale Field Study In Maine, Usa, Bryn E. Evans

Electronic Theses and Dissertations

Understanding trends in the abundance and distribution of carnivores is important at global, regional and local scales due to their ecological role, their aesthetic and economic value, and the numerous threats to their populations. Carnivores in Maine range from the American black bear (Ursus americanus), to numerous native mesocarnivore species, such as American marten (Martes americana), fisher (Pekania pennanti), coyote (Canis latrans), red fox (Vulpes vulpes), bobcat (Lynx rufus), Canada lynx (Lynx canadensis) and to two small weasel species (Mustela erminea and Neogale frenata). …


Gradient Generating Microfluidic Coculture System For Disease Modeling And Neural Development, Phaneendra Chennampally Dec 2021

Gradient Generating Microfluidic Coculture System For Disease Modeling And Neural Development, Phaneendra Chennampally

Electronic Theses and Dissertations

Cellular microenvironment or cell niche plays an important role in developmental biology and disease pathophysiology. Physical or chemical signals in microenvironment drive the cellular activity. These signaling molecules are generated from the surrounding cells/tissues as part of intercellular communication; a fundamental property of a cell. Dynamic profile of these signaling molecules in the microenvironment plays a pivotal role in transfer of molecular information from cell to cell in disease proliferation or fate determination. Recapitulating these signaling cues in an in vitro study is difficult to achieve using standard cell culture techniques. However microfluidic systems are capable of addressing these issues, …


Experimental Warming Effects On Growth, Yield, And Biotic Pressure Of Wild Blueberries In Maine, Yu-Ying Chen Dec 2021

Experimental Warming Effects On Growth, Yield, And Biotic Pressure Of Wild Blueberries In Maine, Yu-Ying Chen

Electronic Theses and Dissertations

As the global temperature rises, a need exists for understanding the potential impacts of warming on the wild blueberry industry in Maine. Warming can change the physiology, growth, and pest pressure of crops, and also accelerates the evapotranspiration rate, resulting in decreased soil moisture. The objectives of this study were: (1) To characterize the response of phenological, morphological, and physiological traits of the wild blueberries to warming; (2) To quantify the impacts of different temperature levels on yield and berry quality; (3) To determine the abiotic and biotic factors that may influence yield, such as winter damages, freezing temperatures, the …


To Know The Land With Hands And Minds: Negotiating Agricultural Knowledge In Late-Nineteenth-Century New England And Westphalia, Justus Hillebrand Aug 2021

To Know The Land With Hands And Minds: Negotiating Agricultural Knowledge In Late-Nineteenth-Century New England And Westphalia, Justus Hillebrand

Electronic Theses and Dissertations

Ever since the eighteenth century, experts have tried to tell farmers how to farm. The agricultural enlightenment in Europe marked the beginning of a long arc of new experts aiming to change agricultural knowledge and practice. This dissertation analyzes the pivotal period in the late nineteenth and early twentieth century in Germany and the United States when scientists, improvers, and market agents began to develop comprehensive ways to communicate agricultural innovation to farmers. In a functional approach to analyzing the negotiation of agricultural knowledge through its communication in things, words, and practices, this dissertation argues that the process of change …


Evaluating Methods For Research In Physical Weed Control And Farm Asset Tracking, Johnny J. Sanchez May 2021

Evaluating Methods For Research In Physical Weed Control And Farm Asset Tracking, Johnny J. Sanchez

Electronic Theses and Dissertations

Effective weed control has long been recognized as critical for agricultural production, yet weeds remain a major constraint to production and economic return in many agroecosystems. Moreover, improvements in physical weed control are necessary to address increasing problems of herbicide resistance in weeds of grain and fiber crops and the high cost of hand weeding in vegetables. From tractor-mounted cultivation tools to autonomous weeders, weeding implements are affected by weeds, crops, soil conditions, and actuator effectiveness. In order to address these complex and often interacting factors concerning weed control, new and innovative tools must be designed and evaluated. Chapter one …


Lexicographic Sensitivity Functions For Nonsmooth Models In Mathematical Biology, Matthew D. Ackley May 2021

Lexicographic Sensitivity Functions For Nonsmooth Models In Mathematical Biology, Matthew D. Ackley

Electronic Theses and Dissertations

Systems of ordinary differential equations (ODEs) may be used to model a wide variety of real-world phenomena in biology and engineering. Classical sensitivity theory is well-established and concerns itself with quantifying the responsiveness of such models to changes in parameter values. By performing a sensitivity analysis, a variety of insights can be gained into a model (and hence, the real-world system that it represents); in particular, the information gained can uncover a system's most important aspects, for use in design, control or optimization of the system. However, while the results of such analysis are desirable, the approach that classical theory …


Farmer Engagement Through Mental Modeling: Opportunities For Climate Change Outreach, Ruth S, Clements May 2021

Farmer Engagement Through Mental Modeling: Opportunities For Climate Change Outreach, Ruth S, Clements

Electronic Theses and Dissertations

Climate change poses a challenge to farming systems worldwide. Effective adaptation and mitigation may be facilitated by outreach that is locally tailored and framed in terms of farmers’ perceptions and values. However, existing research suggests that farmers and those providing outreach may have different climate change perspectives, and there is little understanding of how farmers consider and prioritize climate change in relation to other aspects of their farming system. Furthermore, the diverse agricultural, economic, social, and environmental challenges farmers face require agricultural research and engagement efforts that can identify and adapt to farmers’ dynamic priorities and perceptions. Mental modeling is …