Physical Sciences and Mathematics Commons^™

Evaluating Spatial Variability In Sediment And Phosphorus Concentration-Discharge Relationships Using Bayesian Inference And Self-Organizing Maps, Kristen L. Underwood, Donna M. Rizzo, Andrew W. Schroth, Mandar M. Dewoolkar

College of Engineering and Mathematical Sciences Faculty Publications

Given the variable biogeochemical, physical, and hydrological processes driving fluvial sediment and nutrient export, the water science and management communities need data-driven methods to identify regions prone to production and transport under variable hydrometeorological conditions. We use Bayesian analysis to segment concentration-discharge linear regression models for total suspended solids (TSS) and particulate and dissolved phosphorus (PP, DP) using 22 years of monitoring data from 18 Lake Champlain watersheds. Bayesian inference was leveraged to estimate segmented regression model parameters and identify threshold position. The identified threshold positions demonstrated a considerable range below and above the median discharge—which has been used previously …

Climate Change And Food Systems: Assessing Impacts And Opportunities, Meredith T. Niles, Richie Ahuja, Jimena M. Esquivel, Nelson Mango, Mil Duncan, Martin Heller, Cristina Tirado

College of Agriculture and Life Sciences Faculty Publications

No abstract provided.

Nutrient Leaching From Compost: Implications For Bioretention And Other Green Stormwater Infrastructure, Stephanie Hurley, Paliza Shrestha, Amanda Cording

College of Agriculture and Life Sciences Faculty Publications

This work is made available under the terms of the Creative Commons Attribution 4.0 International license,. Compost is often used as a soil amendment in gardens, agricultural fields, and other landscaped systems to alter soil biophysical characteristics and increase availability of valuable nutrients including nitrogen (N), phosphorus (P), and carbon (C). However, leaching of soluble nutrients from compost is of concern, particularly in wet settings, such as within green stormwater infrastructure, riparian areas, and floodplains. This research highlights the importance of saturation as an influencing factor on the nutrient leaching potential of different composts and compost-amended bioretention soils. Nutrient leaching …

Addressing Climate Change Impacts On Agriculture And Natural Resources: Barriers And Priorities For Land-Grant Universities In The Northeastern United States, Daniel Tobin, Rama Radhakrishna, Allison Chatrchyan, Shorna B. Allred

College of Agriculture and Life Sciences Faculty Publications

Climate change has serious implications for agricultural production, natural resource management, and food security. In the United States, land-grant universities and the U.S. Cooperative Extension System have a critical role to play in conducting basic and applied research related to climate change and translating findings into meaningful programming. However, land-grant universities and Extension have had difficulty maintaining their roles as the preeminent source of trusted information on complex topics like climate change. To help guide research and programming agendas of land-grant universities, the authors explored the barriers and priorities that researchers and Extension personnel at 16 northeastern land-grant universities perceive …

An Automated Approach To Map Winter Cropped Area Of Smallholder Farms Across Large Scales Using Modis Imagery, Meha Jain, Pinki Mondal, Gillian L. Galford, Greg Fiske, Ruth S. Defries

Rubenstein School of Environment and Natural Resources Faculty Publications

Fine-scale agricultural statistics are an important tool for understanding trends in food production and their associated drivers, yet these data are rarely collected in smallholder systems. These statistics are particularly important for smallholder systems given the large amount of fine-scale heterogeneity in production that occurs in these regions. To overcome the lack of ground data, satellite data are often used to map fine-scale agricultural statistics. However, doing so is challenging for smallholder systems because of (1) complex sub-pixel heterogeneity; (2) little to no available calibration data; and (3) high amounts of cloud cover as most smallholder systems occur in the …

Effect Of Drive Row Ground Covers On Hop (Rosales: Cannabaceae) Yard Arthropod Pests In Vermont, Usa, L. Calderwood, J. Cubins, D. Vesty, H. Darby

College of Agriculture and Life Sciences Faculty Publications

Alternatives to pesticides are necessary for the management of hop (Humulus lupulus L.) arthropod pests. The three major arthropod pests in northeastern US hop production include two-spotted spider mite, Tetranychus urticae Koch, hop aphid Phorodon humuli (Schrank), and potato leafhopper, Empoasca fabae Harris. This 3-yr study (2012-2014) in Vermont investigated the effect of flowering ground covers on arthropod pest abundance. Hop cultivars 'Nugget' and 'Cascade' were evaluated under a strip-split plot experimental design. Ground cover treatments included 1) Control: mowed red clover (Trifolium pratense) and resident weeds, 2) Clover: red clover, and 3) Diverse: common yarrow (Achillea millefolium), beebalm (Monarda …

The Use Of Extrafloral Nectar In Pest Management: Overcoming Context Dependence, Ian Matthew Jones, Suzanne Koptur, Eric J. Von Wettberg

College of Agriculture and Life Sciences Faculty Publications

Extrafloral nectar (EFN) provides plants with indirect defence against herbivores by attracting predatory insects, predominantly ants. Decades of research have supported the role of EFN as an effective plant defence, dating back to Thomas Belt's description of ants on acacia in 1874. Despite this extensive body of literature, knowledge of the ecological role of EFN has rarely been applied in the field of pest management. We review the existing literature on the use of EFN in agriculture and consider the obstacles that have hindered this transition. Chief among these obstacles is the influence of ecological context on the outcome of …

Policies For Reintegrating Crop And Livestock Systems: A Comparative Analysis, Rachael D. Garrett, Meredith Niles, Juliana Gil, Philip Dy, Julio Reis, Judson Valentim

College of Agriculture and Life Sciences Faculty Publications

The reintegration of crop and livestock systems within the same land area has the potential to improve soil quality and reduce water and air pollution, while maintaining high yields and reducing risk. In this study, we characterize the degree to which federal policies in three major global food production regions that span a range of socioeconomic contexts, Brazil, New Zealand, and the United States, incentivize or disincentivize the use of integrated crop and livestock practices (ICLS). Our analysis indicates that Brazil and New Zealand have the most favorable policy environment for ICLS, while the United States provides the least favorable …

Integrating Fisheries And Agricultural Programs For Food Security, Brendan Fisher, Robin Naidoo, John Guernier, Kiersten Johnson, Daniel Mullins, Dorcas Robinson, Edward H. Allison

Rubenstein School of Environment and Natural Resources Faculty Publications

Background: Despite the connections between terrestrial and marine/freshwater livelihood strategies that we see in coastal regions across the world, the contribution of wild fisheries and fish farming is seldom considered in analyses of the global food system and is consequently underrepresented in major food security and nutrition policy initiatives. Understanding the degree to which farmers also consume fish, and how fishers also grow crops, would help to inform more resilient food security interventions. Results: By compiling a dataset for 123,730 households across 6781 sampling clusters in 12 highly food-insecure countries, we find that between 10 and 45% of the population …

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 …

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 …

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 …

Reducing Greenhouse Gas Emissions In Agriculture Without Compromising Food Security?, Stefan Frank, Petr Havlík, Jean François Soussana, Antoine Levesque, Hugo Valin, Eva Wollenberg, Ulrich Kleinwechter, Oliver Fricko, Mykola Gusti, Mario Herrero, Pete Smith, Tomoko Hasegawa, Florian Kraxner, Michael Obersteiner

Rubenstein School of Environment and Natural Resources Faculty Publications

To keep global warming possibly below 1.5◦C and mitigate adverse effects of climate change, agriculture, like all other sectors, will have to contribute to efforts in achieving net negative emissions by the end of the century. Cost-efficient distribution of mitigation across regions and economic sectors is typically calculated using a global uniform carbon price in climate stabilization scenarios. However, in reality such a carbon price would substantially affect food availability. Here, we assess the implications of climate change mitigation in the land use sector for agricultural production and food security using an integrated partial equilibrium modelling framework and explore ways …

Challenges Facing Gap-Based Silviculture And Possible Solutions For Mesic Northern Forests In North America, Christel C. Kern, Julia I. Burton, Patricia Raymond, Anthony W. D'Amato, William S. Keeton, Alejandro A. Royo, Michael B. Walters, Christopher R. Webster, John L. Willis

Rubenstein School of Environment and Natural Resources Faculty Publications

Gap-based silvicultural systems were developed under the assumption that richness, and diversity of tree species and other biota positively respond to variation in size of harvest-created canopy gaps. However, varying gap size alone often does not meet diversity objectives and broader goals to address contemporary forest conditions. Recent research highlights the need to consider site factors and history, natural disturbance models, within-gap structure and recruitment requirements in addition to light resources for desired tree diversity. This synthesis brings together silvicultural developments and ecological literature on gap-based management, highlighting interactions with other factors such as microsite conditions, non-tree vegetation and more. …

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 …

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 …

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 …

Harnessing Local Strength For Sustainable Coffee Value Chains In India And Nicaragua: Reevaluating Certification To Global Sustainability Standards, Dagmar Mithöfer, V. Ernesto Méndez, Arshiya Bose, Philippe Vaast

College of Agriculture and Life Sciences Faculty Publications

Coffee is generally grown in areas derived from forest, and both its expansion and management cause biodiversity loss. Sustainability standards in coffee are well established but have been criticized while social and environmental impact is elusive. This paper assesses the issue-attention cycle of coffee production in India and Nicaragua, including producer concerns and responses over time to concerns (sustainability standards, public regulations and development projects). Systematic comparison of the socioeconomic, environmental and policy context in both countries is then used to explore potential effects of sustainability standards. Results show limits, in local context, to relevance of global certification approaches: in …

Integrating Agroecology And Participatory Action Research (Par): Lessons From Central America, V. Ernesto Méndez, Martha Caswell, Stephen R. Gliessman, Roseann Cohen

College of Agriculture and Life Sciences Faculty Publications

The last decade has seen an increasing advancement and interest in the integration of agroecology and participatory action research (PAR). This article aims to: (1) analyze the key characteristics and principles of two case studies that integrated PAR and agroecology in Central America; and (2) learn from the lessons offered by these case studies, as well as others from the literature, on how to better integrate PAR and agroecology. Key principles identified for effective PAR agroecological processes include a shared interest in research by partners, a belief in collective power/action, a commitment to participation, practicing humility and establishing trust 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. …