Life Sciences Commons^™

Effects Of Melatonin On Heartbeat And Possible Identification Of A Melatonin Receptor In Drosophila Melanogaster, Tricia L. Vankirk

Electronic Theses and Dissertations

Chapter 1 of this manuscript is a literature review that serves as an introduction to the entire dissertation. Chapter 2 examines the effects of the melatonin injection on heart rate and rhythmicity in Drosophila melanogaster Canton-S (wild-type) pupae and pupae bearing a variety of heart mutations. Chapter 3 investigates further the possible mechanisms of melatonin’s ability to increase heart rhythmicity without significantly affecting heart rate. A melatonin antagonist, luzindole; a high-affinity melatonin agonist, 2-iodomelatonin and RNAi techniques are used to identify a possible melatonin receptor in Drosophila melanogaster.

An appendix contains a previously published manuscript detailing experiments performed at the …

Thinking Beyond The Fried Egg Model: How Accurately Do Students Perceive Cells In A Living Context?, Milissa Knox

Electronic Theses and Dissertations

This exploratory study investigated three aspects of introductory undergraduate biology students’ understanding about cells. The study, which took place at the University of Maine with voluntary students in Basic Biology (“BIO100”) in the summer and fall of 2009, examined (1) students’ pre-course perceptions of cells as they exist in a living context and (2) gains in students’ perception and knowledge about cells after completing the one-semester course (BIO100). Results are based on lecture exam scores, pre-post surveys developed as a part of this thesis, and interviews with two groups of biology students. A total of 498 students participated in the …

The Temporal Nature Of The Acute Stress Response And Its Impact On Explicit Learning, Steven B. Hutchinson

Electronic Theses and Dissertations

Acute stress is commonly experienced by many throughout their lives. Given the demanding lifestyle of many career paths, it's important to gauge the influence of these stressors upon cognitive performance. The present dissertation focus' upon explicit learning in attempts to explore one avenue of the stress-cognition relationship. The Trier Social Stress Test (TSST) was used as a lab stressor for Experiments 1 and 2, in which participants are asked to give a speech and complete a difficult math task in front of 2 evaluators trained to monitor non-verbal behavior. Experiment 1 investigates the dynamic stress response during the minutes following …

Explaining Migratory Behaviors Using Optimal Migration Theory, Jennifer D. Mccabe

Electronic Theses and Dissertations

Bird migration is the regular seasonal movements between breeding and nonbreeding grounds. In general, birds that breed in the Northern Hemisphere tend to migrate northward in the spring to take advantage of increasing insect populations and lower predation pressures and fly south when food availability and weather conditions decline. Embarking on a journey that can stretch a thousand miles round trip is a dangerous and arduous undertaking. While en route migrants must stop and feed to replenish their depleted energy reserves, often in unfamiliar locations with unknown predation pressures. They also must react to weather conditions during flight and while …

Development Of Cerceis Fumipennis For Biosurveillance Of The Emerald Ash Borer In The Northeast, Jennifer Lund

Electronic Theses and Dissertations

One method being utilized for detection of the invasive emerald ash borer, Agrilus planipennis (EAB) involves monitoring aggregations of the wasp Cerceris fumipennis for the presence of EAB in their collected prey. Currently there is little information published on its nest structure, phenology, and prey fidelity. The objectives of this research were to: i) monitor C. fumipennis male and female emergence, female prey collection, and number of colonies relative to the accumulation of degree-days (DD) throughout the summer; ii) better understand nest structure, phenology, and prey requirements of C. fumipennis; and iii) investigate C. fumipennis prey selection and fidelity. …

Biogeography And Conservation Of Tidal Marsh Bird Communities Across A Changing Landscape, Maureen D. Correll

Electronic Theses and Dissertations

Given the current mass extinction crisis and continued fragmentation of resources worldwide, the outlook is dire for global biodiversity. Rising global temperature, sea levels, and storm frequency all create environmental conditions that can drive change in species abundance and distribution across a landscape. Those species reliant upon a single type of habitat and resource for survival, termed “specialists”, are particularly vulnerable to change due to their inability to utilize a variety of resources well. As a result, specialism is now considered one of the dominant factors determining extinction of species. In this dissertation I explore the effects of disturbance on …

Development Of A 3-Pronged Approach To Evaluation For The Icook-4h Project, Douglas R. Mathews

Electronic Theses and Dissertations

Most nutrition education programs are created without adequate forethought to planning evaluation strategies. The goal of this study was to develop and implement a comprehensive 3-pronged approach to evaluate iCook 4-H, a six- session, biweekly program for 9-10 year old youth and their adult main food preparer. It was used to evaluate the curriculum for the intervention of a 2-year childhood obesity prevention study. Forty iCook 4-H classes were implemented for 150 dyads by 16 leaders between September and December, 2013, in Maine, Nebraska, South Dakota, Tennessee, and West Virginia. The evaluation included measures of fidelity of implementation, process evaluation, …

Improving Extraction Of Allergenic Soy Proteins From Soy Products, Amma Konadu Amponsah

Electronic Theses and Dissertations

With recent increase in the utilization of soy proteins, there are mounting concerns of the escalation of soy allergies. It is, therefore, important to improve current methods of allergen detection to ensure accurate labeling of foods, produce more reliable and representative results in studies to create hypoallergenic food and establish allergen thresholds. The conditions used to extract proteins from foods are important determinants for appropriate detection and interpretation of the allergenicity of food materials. The extraction of soy proteins for soy allergen detections is conventionally performed with phosphate buffered saline (PBS) buffer for an extraction period of at least 2 …

Reproductive Ecology Of Black Bears In Maine: Maternal Effect, Philopatry, And Primiparity, Alyssa A. Vitale

Electronic Theses and Dissertations

The American black bear (Ursus americanus) relies upon dens in order to successfully reproduce and protect their offspring. Black bears utilize a variety of den types, each providing a different degree of protection. Black bears also exhibit an extended maternal care period in which offspring stay with their mother for 18 months. Maine’s black bear population is one of the largest in the U.S. (>30,000 bears) and since 1975, the Maine Department of Inland Fisheries and Wildlife has conducted research and monitoring to manage the population. This unique dataset allowed for examination of several generations of multiple …

Implementing Complex Partial Harvests In Central Maine: Is Tree Marking Necessary?, Sam Grimm

Electronic Theses and Dissertations

Recent trends in forest management regimes seek to strike a balance between a multitude of ecologic and economic values at multiple scales. Whether the objectives are traditional (timber production), or contemporary (ecological sustainability), the fundamental, practical question of “how” the forester implements a silvicultural prescription remains relatively unaddressed by research. Forest managers must consider: what good are carefully designed landscape plans and stand-level prescriptions if the treatments are not executed accurately? In northeastern North America, tree marking -- the simple designation of cut or leave trees to implement a given silvicultural prescription -- has declined, in favor of reliance on …

Method Development For Vitamin C Quantification In Two Complex Matrices, Hannah D. Hutt

Electronic Theses and Dissertations

The following liquid chromatographic (LC) method developments and applied research studies were done using two complex food matrices, potatoes and elderberries, which are common to the state of Maine. Potatoes are Maine’s largest agricultural crop, a staple food in most U.S. households, and are, from an analytical standpoint, considered a complex matrix due to the high starch content that can be difficult to remove without degrading or removing nutrients in the process. Elderberries are an emerging crop in the U.S. because of their antioxidant and anti-viral properties and are found growing wild, throughout Maine. Elderberries are also considered a complex …

Intra- And Interspecific Variation In Demographic Rates And Niche Across The Range Of A Species, The Saltmarsh Sparrow (Ammodramus Caudacutus), Katharine J. Ruskin

Electronic Theses and Dissertations

In this project, we examined various hypotheses that address one of the fundamental questions in ecology and evolution: what determines the range of a species? We used demographic data for saltmarsh sparrows (Ammodramus caudacutus) collected over the majority of the global breeding range. Saltmarsh sparrows are considered threatened by climate change, specifically sea level rise, which is predicted to result in loss of the tidal marsh habitat where saltmarsh sparrows live across their entire life cycle. For my dissertation, I investigated the reproductive biology of saltmarsh sparrows both to provide vital information for wildlife managers and to explore …

Forest Harvesting Productivity And Cost In Maine: New Tools And Processes, Patrick Hiesl

Electronic Theses and Dissertations

Computer simulations have been used in forestry and forest operations since around 1960. In many cases such simulations can be used to answer questions that would be time consuming and expensive to investigate in a real-life environment. This dissertation focuses on the use of computer simulation in forest operations to answer questions regarding the profitability of technological advancements, investments in precommercial thinning (PCT), and the use of different harvesting systems. To explore the benefits of decoupling a harvesting system, a new simulation method, called agent based modeling was used. Agent based modeling is primarily used in social sciences but now …

Survival And Growth Of Reserve Trees In An Expanding-Gap Silvicultural System 20 Years After Establishment, David R. Carter

Electronic Theses and Dissertations

Land managers today are increasingly called upon to retain and restore late-successional features on harvested landscapes in order to reverse the current global decline of large, old trees and their associated elevated levels of biodiversity and ecosystem function. Such retention practices are commonly thought to result in increased rates of mortality as a result of exposure to wind, thus compromising management objectives. This study investigated the survival and growth dynamics of the reserve trees retained in harvested gaps (n=787) established 20 years prior in the Acadian Forest Ecosystem Research Project (AFERP) in east-central Maine.

A high (relative to similar treatments …

The Enhancement Of Wild Bees (Hymenoptera: Apoidea) For Pollination Security, Eric M. Venturini

Electronic Theses and Dissertations

The acreage of pollinator-dependent crops continues to expand across the globe. Simultaneously, honey bee hives – an annually rented commodity that growers rely on – are more expensive every year and in some cases, scarce. In response, pollinator-dependent growers seek alternative pollinators. One approach is installing bee pasture on farms, a strategy that enables systems-based farmers to become in-situ farm-scale habitat managers. This thesis first presents a review of the literature on bee pasture plantings and provides a brief overview of some methods for assessing their impacts on the pollinator community. There are three major gaps in current bee pasture …

Individual Tree Measurements From Three-Dimensional Point Clouds, Elias Ayrey

Electronic Theses and Dissertations

This study develops and tests novel methodologies for measuring the attributes of individual trees from three-dimensional point clouds generated from an aerial platform. Recently, advancements in technology have allowed for the acquisition of very high resolution three-dimensional point clouds that can be used to map the forest in a virtual environment. These point clouds can be interpreted to produce valuable forest attributes across entire landscapes with minimal field labor, which can then aid forest managers in their planning and decision making.

Biometrics derived from point clouds are often generated on a plot level, with estimates spanning many meters (rather than …

Microengineering The Neural Tube, Christopher Demers

Electronic Theses and Dissertations

Early embryonic development is a complex and highly regulated orchestra of instructive cues that collectively guide naïve stem cells towards progressively more specialized fates. In the neural tube, the precursor structure to the brain and spinal cord, these signals emanate from ‘organizing centers’ surrounding the neural tube. These organizing centers send out soluble cues or morphogens that diffuse tens to hundreds of microns to recipient cells residing in the neural tube. Re-creating this dynamic landscape of cues in vitro is impossible using standard cell culture tools and techniques. However, microfluidics is perfectly suited to fill this gap, allowing precise control …

The Relationship Between The Winter Moth (Operophtera Brumata) And Its Host Plants In Coastal Maine, Kaitlyn M. O'Donnell

Electronic Theses and Dissertations

This project examines the recent outbreak of the invasive winter moth (Operophtera brumata) in mid-coast Maine. The winter moth was introduced into New England in the late 1990’s and low densities of winter moth were detected with pheromone traps throughout the Maine coast in 2006. Severe defoliation occurred for the first time in Maine in the spring of 2012 in Harpswell and Vinalhaven, ME. This pest attacks an extremely broad range of host plants, including forest hardwood trees and agricultural crops such as highbush blueberry and apple. The objectives of this study are to examine the differential development …

Investigating The Effects Of Particulate Hexavalent Chromium On The Centriole Linkers, Julieta Martino

Electronic Theses and Dissertations

Particulate hexavalent chromium (Cr(VI)) compounds are human lung carcinogens. However, their carcinogenicity is poorly understood. The best model for Cr(VI)-induced carcinogenesis involves the acquisition of structural and numerical chromosome instability (CIN). Many mechanisms contribute to CIN. Among these, centrosomes play a pivotal role because they dictate proper segregation of chromosomes during cell division. Cr(VI) causes centrosome amplification, a phenotype where cells have extra centrosomes and hence can undergo unequal distribution of chromosomes resulting in CIN. How Cr(VI) induces these abnormalities is unknown. Moreover, whether Cr(VI)-induced centrosome amplification is a permanent phenotypic change is also unknown. This work investigates the permanence …

Seasonal Influences On Habitat Use By Snowshoe Hares: Implications For Canada Lynx In Northern Maine, Sheryn J. Olson

Electronic Theses and Dissertations

Snowshoe hares (Lepus americanus) respond to seasonal changes in vegetation in the northern and western portions of their range. During winter, hares use dense conifer stands that may provide thermal and predatory refugia, then during summer move to areas with more herbaceous food and cover. These movements influence hare demographics, with greater survival rates corresponding to seasonal use of dense, primarily coniferous stands. Different harvesting practices in commercial forests produce vegetative communities that may support differing hare densities among forest stand- types between seasons, but seasonal use of habitat had not been documented in northern Maine on a large spatial …