Physical Sciences and Mathematics Commons^™

Lasting Legacies Of Hurricane, Harvesting, And Salvage Logging Disturbance On Succession And Structural Development In An Old-Growth Tsuga Canadensis-Pinus Strobus Forest, Emma Sass

Graduate College Dissertations and Theses

Disturbance events affect forest composition and structure across a range of spatial and temporal scales, and forest development may differ after natural, anthropogenic, or compound disturbances. Following large, natural disturbances, salvage logging is a common yet controversial management practice around the globe. While the short-term impacts of salvage logging have been studied in many systems, the long-term effects remain unclear. Further, while natural disturbances create many persistent and unique microsite conditions, little is known about the long-term influence of microsites on forest development. We capitalized on over eighty years of data on stand development following the 1938 hurricane in New …

Choices And Preferences Of Vermont Master Gardeners - Do Socio-Demographics Matter?, Grace Matiru

Graduate College Dissertations and Theses

ABSTRACT

This study was designed to characterize the choices, preferences and motivations of fruit and vegetable gardeners in Vermont, and to determine whether socio-demographic characteristics affect some of these choices, preferences and motivations. Using a survey of Vermont Extension Master Gardeners (EMGs), data were gathered over a 3-year period (2011-2013). The findings show most EMGs (>90%) garden in private home gardens, and the most popular vegetables grown were tomatoes, herbs, and salad greens. Beans, cucumbers and peppers sere also popular and among fruits, blueberries, apples, raspberries and strawberries were grown by over 40% of EMGs. Approximately 10% of EMG …

Silica Nanoparticles For The Delivery Of Dna And Rnai In Cancer Treatment, Michael Aaron Vrolijk

Graduate College Dissertations and Theses

DNA and interfering RNA (RNAi) – short interfering RNA (siRNA) and micro RNA (miRNA) – are promising new cancer therapies, especially for drug resistant lines. However, they require a delivery system in vivo to prevent degradation and off target effects. Silica based nanoparticles, both solid and mesoporous, are a promising option due to their biocompatibility, ease of preparation and morphology control, reproducibility, and facile addition of functional groups including targeting ligands.

After a brief introduction to cancer treatment and review of the current nanoparticle treatments undergoing clinical trials, this thesis details the many methods explored over the past ten years …

Using Multiple Methodologies To Understand Within Species Variability Of Adelges And Pineus (Hemiptera: Sternorrhyncha), Tav Aronowitz

Graduate College Dissertations and Theses

The species of two genera in Insecta: Hemiptera: Adelgidae were investigated through the lenses of genetics, morphology, life cycle and host species. The systematics are unclear due to complex life cycles, including multigenerational polymorphism, host switching and cyclical parthenogenesis. I studied the hemlock adelgids, including the nonnative invasive hemlock woolly adelgid on the east coast of the United States, that are currently viewed as a single species. I used multivariate morphometric analyses to identify morphological differences among hemlock adelgid lineages. With principal component analyses and MANOVA, the six lineages that were used in this study were found to be significantly …

Quantifying Tree Response To Alterations In Pollution Deposition And Climate Change In The Northeastern Us, Alexandra M. Kosiba

Graduate College Dissertations and Theses

Understanding tree physiological responses to climate change is critical for quantifying forest carbon, predicting species' range change, and forecasting growth trajectories. Continued increases in temperature could push trees into conditions to which they are ill adapted -- such as decreased depth of winter snow cover, altered water regimes, and a lengthened effective growing season. A complicating factor is that in the northeastern United States, climate change is occurring on a backdrop of acid deposition and land-use change. In this dissertation, I used three studies to investigate the spatiotemporal nuances of resultant tree and sapling physiology to environmental change.

First, I …

Role Of Community Social Capital For Acute Food Security Following An Extreme Weather Event, Alana N. Chriest

Graduate College Dissertations and Theses

Worsening climate changes effects are predicted to increase the severity and frequency of extreme weather events (EWE), which can disrupt food systems, from the local to global level, and compromise community food security. In the rural U.S., food insecurity, poverty, low economic growth, and population loss are prevalent, and rural communities often lack the physical capital to bolster community resiliency to climate change adaptation. In 2011, Tropical Storm Irene (TS Irene) in Vermont was the most damaging EWE the state’s history. Severely damaged roads, infrastructure, homes, and land, rendered many rural towns isolated for up to several days. The levels …

New Approaches To Heterocycle Synthesis: A Greener Route To Structurally Complex Protonated Azomethine Imines, And Their Use In 1,3-Dipolar Cycloadditions, Ram Chandra Dhakal

Graduate College Dissertations and Theses

1-Aza-2-azoniaallene salts are reactive intermediates that undergo [3+2] cycloaddition with many different types of multiple bonds. For the past several years, the Brewer group has studied the reactivity of these intermediates in intramolecular reactions, and have discovered that these cationic heteroallenes can react through a variety of other, mechanistically distinct, pathways to give different classes of nitrogen heterocycles. For example, prior work in the Brewer group revealed that 1-aza-2-azoniaallene salts could react in an intramolecular [4+2] cycloaddition reaction to give protonated azomethine imine salts containing a 1,2,3,4-tetrahydrocinnoline scaffold. Further study of the scope and limitations of this Diels-Alder-like reaction are …

Regeneration Responses To Management For Old-Growth Characteristics In Northern Hardwood-Conifer Forests, Aviva Joy Gottesman

Graduate College Dissertations and Theses

Silviculture practices interact with multiple sources of variability to influence regeneration trends in northern hardwood forests. There is uncertainty whether low-intensity selection harvesting techniques will result in desirable tree regeneration. Our research is part of a long-term study that tests the hypothesis that a silvicultural approach called "structural complexity enhancement" (SCE) can promote accelerated development of late-successional forest structure and functions. Our objective is to understand the regeneration dynamics following three uneven-aged forestry treatments modified to increase postharvest structural retention: single-tree selection, group selection, and SCE. In terms of regeneration densities and composition, how do light availability, competition, seedbad, and …

Early Feeding In Lake Trout Fry (Salvelinus Namaycush) As A Mechanism For Ameliorating Thiamine Deficiency Complex, Carrie L. Kozel

Graduate College Dissertations and Theses

Recruitment failure of lake trout (Salvelinus namaycush) in the Great Lakes has been attributed in part to the consumption of alewife (Alosa pseudoharengus) by adult lake trout, leading to Thiamine Deficiency Complex (TDC) and early mortality in fry. The current understanding of thiamine deficiency in lake trout fry is based on information from culture and hatchery settings, which do not represent conditions fry experience in the wild and may influence the occurrence of TDC. In the wild, lake trout fry have access to zooplankton immediately following hatching; previous studies found that wild fry begin feeding before complete yolk-sac absorption. However, …

Predictive Modeling Of Adolescent Cannabis Use From Multimodal Data, Philip Spechler

Graduate College Dissertations and Theses

Predicting teenage drug use is key to understanding the etiology of substance abuse. However, classic predictive modeling procedures are prone to overfitting and fail to generalize to independent observations. To mitigate these concerns, cross-validated logistic regression with elastic-net regularization was used to predict cannabis use by age 16 from a large sample of fourteen year olds (N=1,319). High-dimensional data (p = 2,413) including parent and child psychometric data, child structural and functional MRI data, and genetic data (candidate single-nucleotide polymorphisms, "SNPs") collected at age 14 were used to predict the initiation of cannabis use (minimum six occasions) by age 16. …